WorldWideScience

Sample records for rapid chemical reduction

  1. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  2. Chemical model reduction under uncertainty

    KAUST Repository

    Najm, Habib

    2016-01-05

    We outline a strategy for chemical kinetic model reduction under uncertainty. We present highlights of our existing deterministic model reduction strategy, and describe the extension of the formulation to include parametric uncertainty in the detailed mechanism. We discuss the utility of this construction, as applied to hydrocarbon fuel-air kinetics, and the associated use of uncertainty-aware measures of error between predictions from detailed and simplified models.

  3. Rapid Chemical Exposure and Dose Research

    Science.gov (United States)

    EPA evaluates the potential risks of the manufacture and use of thousands of chemicals. To assist with this evaluation, EPA scientists developed a rapid, automated model using off the shelf technology that predicts exposures for thousands of chemicals.

  4. Chemical model reduction under uncertainty

    KAUST Repository

    Malpica Galassi, Riccardo

    2017-03-06

    A general strategy for analysis and reduction of uncertain chemical kinetic models is presented, and its utility is illustrated in the context of ignition of hydrocarbon fuel–air mixtures. The strategy is based on a deterministic analysis and reduction method which employs computational singular perturbation analysis to generate simplified kinetic mechanisms, starting from a detailed reference mechanism. We model uncertain quantities in the reference mechanism, namely the Arrhenius rate parameters, as random variables with prescribed uncertainty factors. We propagate this uncertainty to obtain the probability of inclusion of each reaction in the simplified mechanism. We propose probabilistic error measures to compare predictions from the uncertain reference and simplified models, based on the comparison of the uncertain dynamics of the state variables, where the mixture entropy is chosen as progress variable. We employ the construction for the simplification of an uncertain mechanism in an n-butane–air mixture homogeneous ignition case, where a 176-species, 1111-reactions detailed kinetic model for the oxidation of n-butane is used with uncertainty factors assigned to each Arrhenius rate pre-exponential coefficient. This illustration is employed to highlight the utility of the construction, and the performance of a family of simplified models produced depending on chosen thresholds on importance and marginal probabilities of the reactions.

  5. Chemical Stockpile Disposal Program rapid accident assessment

    Energy Technology Data Exchange (ETDEWEB)

    Chester, C.V.

    1990-08-01

    This report develops a scheme for the rapid assessment of a release of toxic chemicals resulting from an accident in one of the most chemical weapon demilitarization plants or storage areas. The system uses such inputs as chemical and pressure sensors monitoring the plant and reports of accidents radioed to the Emergency Operations Center by work parties or monitoring personnel. A size of release can be estimated from previous calculations done in the risk analysis, from back calculation from an open-air chemical sensor measurement, or from an estimated percentage of the inventory of agent at the location of the release. Potential consequences of the estimated release are calculated from real-time meteorological data, surrounding population data, and properties of the agent. In addition to the estimated casualties, area coverage and no-death contours vs time would be calculated. Accidents are assigned to one of four categories: community emergencies, which are involve a threat to off-site personnel; on-post emergencies, which involve a threat only to on-site personnel; advisory, which involves a potential for threat to on-site personnel; and chemical occurrence, which can produce an abnormal operating condition for the plant but no immediate threat to on-site personnel. 9 refs., 20 tabs.

  6. Methanogens rapidly transition from methane production to iron reduction.

    Science.gov (United States)

    Sivan, O; Shusta, S S; Valentine, D L

    2016-03-01

    Methanogenesis, the microbial methane (CH4 ) production, is traditionally thought to anchor the mineralization of organic matter as the ultimate respiratory process in deep sediments, despite the presence of oxidized mineral phases, such as iron oxides. This process is carried out by archaea that have also been shown to be capable of reducing iron in high levels of electron donors such as hydrogen. The current pure culture study demonstrates that methanogenic archaea (Methanosarcina barkeri) rapidly switch from methanogenesis to iron-oxide reduction close to natural conditions, with nitrogen atmosphere, even when faced with substrate limitations. Intensive, biotic iron reduction was observed following the addition of poorly crystalline ferrihydrite and complex organic matter and was accompanied by inhibition of methane production. The reaction rate of this process was of the first order and was dependent only on the initial iron concentrations. Ferrous iron production did not accelerate significantly with the addition of 9,10-anthraquinone-2,6-disulfonate (AQDS) but increased by 11-28% with the addition of phenazine-1-carboxylate (PCA), suggesting the possible role of methanophenazines in the electron transport. The coupling between ferrous iron and methane production has important global implications. The rapid transition from methanogenesis to reduction of iron-oxides close to the natural conditions in sediments may help to explain the globally-distributed phenomena of increasing ferrous concentrations below the traditional iron reduction zone in the deep 'methanogenic' sediment horizon, with implications for metabolic networking in these subsurface ecosystems and in past geological settings. © 2016 John Wiley & Sons Ltd.

  7. Hazardous Chemical Discharge Prevention and Reduction.

    Science.gov (United States)

    1984-05-01

    Agency. - Hazardous Mlaterials - Other chemicals, dangerous articles or coimodities regulated by the U.S. Coast Guard by such laws as the Tank Vessel...Act and the Dangerous Cargo Act. - Hazardous Chemicals - A generic term encompassing all of the above and any other hazardous chemicals not included in... Lait 4151.3.1 cae As -0mig L~een study Sub Week~ imit 4151.3.1.1 1~bWal Limi 411 3 1.31. fiVIediang Syst* Walk Lbit 4151.3.3 O1IS List Pumaebility

  8. Toxic chemicals: risk prevention through use reduction

    National Research Council Canada - National Science Library

    Higgins, Thomas E; Sachdev, Jayanti A; Engleman, Stephen A

    2011-01-01

    ... on the actual toxicity of chemicals currently in use, discusses variables that contribute to the relative toxicity of a substance, compares alternate emphases in existing programs for reducing environmental...

  9. Toxic chemicals: risk prevention through use reduction

    National Research Council Canada - National Science Library

    Higgins, Thomas E; Sachdev, Jayanti A; Engleman, Stephen A

    2011-01-01

    "Catastrophic events such as the Bhopal, India tragedy and rising incidences of cancer in areas neighboring industrial facilities have heightened concern over the use of toxic chemicals in manufacturing and industry...

  10. Order reduction of the chemical master equation via balanced realisation.

    Directory of Open Access Journals (Sweden)

    Fernando López-Caamal

    Full Text Available We consider a Markov process in continuous time with a finite number of discrete states. The time-dependent probabilities of being in any state of the Markov chain are governed by a set of ordinary differential equations, whose dimension might be large even for trivial systems. Here, we derive a reduced ODE set that accurately approximates the probabilities of subspaces of interest with a known error bound. Our methodology is based on model reduction by balanced truncation and can be considerably more computationally efficient than solving the chemical master equation directly. We show the applicability of our method by analysing stochastic chemical reactions. First, we obtain a reduced order model for the infinitesimal generator of a Markov chain that models a reversible, monomolecular reaction. Later, we obtain a reduced order model for a catalytic conversion of substrate to a product (a so-called Michaelis-Menten mechanism, and compare its dynamics with a rapid equilibrium approximation method. For this example, we highlight the savings on the computational load obtained by means of the reduced-order model. Furthermore, we revisit the substrate catalytic conversion by obtaining a lower-order model that approximates the probability of having predefined ranges of product molecules. In such an example, we obtain an approximation of the output of a model with 5151 states by a reduced model with 16 states. Finally, we obtain a reduced-order model of the Brusselator.

  11. Order reduction of the chemical master equation via balanced realisation.

    Science.gov (United States)

    López-Caamal, Fernando; Marquez-Lago, Tatiana T

    2014-01-01

    We consider a Markov process in continuous time with a finite number of discrete states. The time-dependent probabilities of being in any state of the Markov chain are governed by a set of ordinary differential equations, whose dimension might be large even for trivial systems. Here, we derive a reduced ODE set that accurately approximates the probabilities of subspaces of interest with a known error bound. Our methodology is based on model reduction by balanced truncation and can be considerably more computationally efficient than solving the chemical master equation directly. We show the applicability of our method by analysing stochastic chemical reactions. First, we obtain a reduced order model for the infinitesimal generator of a Markov chain that models a reversible, monomolecular reaction. Later, we obtain a reduced order model for a catalytic conversion of substrate to a product (a so-called Michaelis-Menten mechanism), and compare its dynamics with a rapid equilibrium approximation method. For this example, we highlight the savings on the computational load obtained by means of the reduced-order model. Furthermore, we revisit the substrate catalytic conversion by obtaining a lower-order model that approximates the probability of having predefined ranges of product molecules. In such an example, we obtain an approximation of the output of a model with 5151 states by a reduced model with 16 states. Finally, we obtain a reduced-order model of the Brusselator.

  12. A robustness screen for the rapid assessment of chemical reactions.

    Science.gov (United States)

    Collins, Karl D; Glorius, Frank

    2013-07-01

    In contrast to the rapidity with which scientific information is published, the application of new knowledge often remains slow, and we believe this to be particularly true of newly developed synthetic organic chemistry methodology. Consequently, methods to assess and identify robust chemical reactions are desirable, and would directly facilitate the application of newly reported synthetic methodology to complex synthetic problems. Here, we describe a simple process for assessing the likely scope and limitations of a chemical reaction beyond the idealized reaction conditions initially reported. Using simple methods and common analytical techniques we demonstrate a rapid assessment of an established chemical reaction, and also propose a simplified analysis that may be reported alongside new synthetic methodology.

  13. Contingency planning for rapid reduction of greenhouse gas emissions

    Directory of Open Access Journals (Sweden)

    Larsson, Nils K.

    2010-03-01

    Full Text Available The current and predicted levels of greenhouse gas (GHG emissions are, according to the best international scientific estimates, leading the world towards climate change that will have serious consequences for all countries. The problem is aggravated by the tendency of people and institutions not to take action until catastrophic consequences emerge. The history of crises in other sectors show us that reactions are likely to focus on ad-hoc reactions or using plans that are readily available, with negative results. However, the alternative of developing public plans for drastic and rapid reductions is not likely to gain support because of their radical nature. The author therefore proposes that large organizations with direct or indirect control over substantial GHG emissions should prepare private contingency plans for very rapid reductions in emissions, so that more rational and less destructive plans will be available when the appropriate moment comes for last-minute action. Examples of the type of specific plans that may be appropriate are suggested.

    Según las estimaciones científicas internacionales más optimistas, los niveles actuales y previstos de emisiones de gases de efecto invernadero (GEI están llevando al mundo hacia un cambio climático que tendrá graves consecuencias para todos los países. El problema se ve agravado por la tendencia de personas e instituciones a no tomar medidas hasta que no se perciben las catastróficas consecuencias. El historial de crisis ocurridas en otros sectores nos demuestra que las reacciones probablemente se centren en medidas ad hoc o en emplear planes que ya existían, pero sin resultados. Sin embargo, es poco probable que la alternativa al desarrollo de planes públicos para las reducciones drásticas y rápidas consiga el apoyo necesario, debido precisamente a su radicalidad. El autor recomienda por tanto que las grandes organizaciones que tengan control directo o indirecto sobre un

  14. Chemical reduction of CO2 facilitated by C-nucleophiles.

    Science.gov (United States)

    Janes, Trevor; Yang, Yanxin; Song, Datong

    2017-10-17

    The abundance of atmospheric CO2 presents both an opportunity and a challenge for synthetic chemists to transform CO2 into value-added products. A promising strategy involves CO2 reduction driven by the energy stored in chemical bonds and promoted by molecules containing nucleophilic carbon sites. This approach allows the synthesis of new C-C or C-H bonds from CO2-derived carbon. The first part of this Feature article deals with uncatalyzed reductions of CO2 such as insertion into metal-carbon bonds and reactivity towards multidentate actor ligands and metal-free compounds. The second part covers catalytic reduction of CO2 in which a nucleophilic C-site is involved. This review brings together two general approaches in the chemical CO2 reduction field, showing how the discovery of fundamental reactivity of CO2 leads to synthetic applications, and proposes directions for further development.

  15. Rapid and reliable protein structure determination via chemical shift threading.

    Science.gov (United States)

    Hafsa, Noor E; Berjanskii, Mark V; Arndt, David; Wishart, David S

    2017-12-01

    Protein structure determination using nuclear magnetic resonance (NMR) spectroscopy can be both time-consuming and labor intensive. Here we demonstrate how chemical shift threading can permit rapid, robust, and accurate protein structure determination using only chemical shift data. Threading is a relatively old bioinformatics technique that uses a combination of sequence information and predicted (or experimentally acquired) low-resolution structural data to generate high-resolution 3D protein structures. The key motivations behind using NMR chemical shifts for protein threading lie in the fact that they are easy to measure, they are available prior to 3D structure determination, and they contain vital structural information. The method we have developed uses not only sequence and chemical shift similarity but also chemical shift-derived secondary structure, shift-derived super-secondary structure, and shift-derived accessible surface area to generate a high quality protein structure regardless of the sequence similarity (or lack thereof) to a known structure already in the PDB. The method (called E-Thrifty) was found to be very fast (often structure) and to significantly outperform other shift-based or threading-based structure determination methods (in terms of top template model accuracy)-with an average TM-score performance of 0.68 (vs. 0.50-0.62 for other methods). Coupled with recent developments in chemical shift refinement, these results suggest that protein structure determination, using only NMR chemical shifts, is becoming increasingly practical and reliable. E-Thrifty is available as a web server at http://ethrifty.ca .

  16. Chemical reactions occurring during direct solar reduction of CO2.

    Science.gov (United States)

    Lyma, J L; Jensen, R J

    2001-09-28

    At high temperatures carbon dioxide may absorb solar radiation and react to form carbon monoxide and molecular oxygen. The CO, so produced, may be converted by well-established means to a combustible fuel, such as methanol. We intend to make a future demonstration of the solar reduction of CO2 based on these processes. This paper, however, addresses only the problem of preserving, or even enhancing, the initial photolytic CO by quenching the hot gas with colder H2O or CO2. We present model calculations with a reaction mechanism used extensively in other calculations. If a CO2 gas stream is heated and photolyzed by intense solar radiation and then allowed to cool slowly, it will react back to the initial CO2 by a series of elementary chemical reactions. The back reaction to CO2 can be terminated with the rapid addition of CO2, water, or a mixture. Calculations show that a three-fold quench with pure CO2 will stop the reactions and preserve over 90% of the initial photolytic CO. We find that water has one of two effects. It can either increase the CO level, or it can catalyze the recombination of O and CO to CO2. The gas temperature is the determining factor. If the quench gas is not sufficient to keep the temperature below approximately 1100 K, a chain-branching reaction dominates and the reaction to CO2 occurs. If the temperature stays below that level a chain terminating reaction dominates and the CO is increased. The former case occurs below approximately a fourfold quench with a water/CO2 mixture. The later case occurs when the quench is greater than fourfold. We conclude that CO2, H2O, or a mixture may quench the hot gas stream photolyzed by solar radiation and preserve the photolytic CO.

  17. Chemical state mapping of heterogeneous reduction of iron ore sinter

    Science.gov (United States)

    Kimura, M.; Takeichi, Y.; Murao, R.; Obayashi, I.; Hiraoka, Y.; Liu, Y.

    2017-06-01

    Iron ore sinter constitutes the major component of the iron-bearing burden in blast furnaces, and its reduction mechanism is one of the keys to improving the productivity of ironmaking. Iron ore sinter is composed of multiple iron oxide phases and calcium ferrites (CFs), and their heterogeneous reduction was investigated in terms of changes in iron chemical state: FeIII, FeII, and Fe0 were examined macroscopically by 2D X-ray absorption and microscopically by 3D transmission X-ray microscopy (TXM). It was shown that the reduction starts at iron oxide grains rather than at calcium ferrite (CF) grains, especially those located near micropores. The heterogeneous reduction causes crack formation and deteriorates the mechanical strength of the sinter. These results help us to understand the fundamental aspects of heterogeneous reduction schemes in iron ore sinter.

  18. Trapping succinimides in aged polypeptides by chemical reduction.

    Science.gov (United States)

    Carter, D A; McFadden, P N

    1994-01-01

    Cyclization of aspartic acid and asparagine to succinimides is thought to be a common spontaneous aging reaction in proteins, but the instability of the succinimide ring has made it difficult to directly measure this structure. Chemical reduction has now been tested as a means of trapping succinimides as stable derivatives, homoserine and isohomoserine. Two succinimide-containing compounds were tested in this manner. First, polysuccinimide was reduced by sodium borohydride to a derivative that contained homoserine and isohomoserine in amounts that were consistent with the content of succinimide determined independently by quantitative hydrolysis. The identity of isohomoserine was confirmed by its resistance to degradation by L-amino acid oxidase, and through its synthesis by an alternate route involving borane reduction of asparagine. Second, in a test of this approach on a peptide mixture with only a trace-content of succinimide, isohomoserine and homoserine were formed as reduction products in amounts equivalent to the trace content of succinimide in the mixture. Detection of the products of the chemical reduction of polypeptides is therefore diagnostic of succinimides, and can be successfully applied at the trace sensitivity necessary for studies of naturally aging proteins. A related study of the reduction of aspartyl and beta-aspartyl residues to, respectively, homoserine and isohomoserine, is described in the accompanying manuscript (Carter and McFadden, 1994).

  19. Bond-controlled configurational entropy reduction in chemical vitrification.

    Science.gov (United States)

    Corezzi, Silvia; Fioretto, Daniele; Rolla, Pierangelo

    2002-12-12

    Glass formation is usually viewed in terms of physical vitrification: a liquid in a metastable state is cooled or compressed so as to avoid crystallization. However, glasses may also be formed by chemical vitrification, a process involving progressive polymerization of the constituent molecules via the formation of irreversible chemical bonds. The formation of most of the materials used in engineering plastics and the hardening of natural and synthetic resins are based on chemical vitrification. Despite the differences in the molecular processes involved in chemical and physical vitrification, surprising similarities are observed in the slowing down of the dynamics and in the thermodynamical properties of the resulting glasses. Explaining such similarities would improve general understanding of the glass transition and may disclose its universal nature. Here we report dielectric and photon-correlation measurements that reveal the origin of the similarity in the dynamical behaviour of physical and chemical glass formers. We find that the evolution of their configurational restrictions proceeds in a similar manner. In particular, we make a connection between the reduction in configurational entropy and the number of chemical bonds, a quantity that can be controlled in experiments.

  20. Kinetics of cyanogen chloride destruction by chemical reduction methods.

    Science.gov (United States)

    Shang, Chii; Qi, Yinan; Xie, Li; Liu, Wei; Yang, Xin

    2005-05-01

    In this study, membrane introduction mass spectrometry (MIMS) was applied to evaluate the kinetics of cyanogen chloride (ClCN) destruction by chemical reduction methods, using thiosulfate, sulfite, metabisulfite, ferrous ions and zero-valent iron at various concentrations and pH. The ClCN destruction followed second-order reaction kinetics in all cases of using sulfur compounds, though the second-order rate constants varied substantially from approximately 0.3-25.7 M(-1)s(-1) under different experimental conditions. The destruction of ClCN was primarily attributable to the chemical reduction pathway. Hydroxide-assisted ClCN hydrolysis was only significant at pH 9 and also when the observed reduction rate was relatively slow. The second-order rate constants achieved by sulfur(IV) compounds in the form of sulfite were found to be higher than those obtained with thiosulfate and S(IV) compounds in the form of bisulfite. Ferrous ions and zero-valent iron demonstrated slow or no ClCN reduction up to dosages of 1000 mgL(-1) and 100 gL(-1), respectively. These findings suggest that applying moderately high dosages of S(IV) compounds under neutral or alkali conditions with sufficient contact time is required for wastewater ClCN destruction. In addition, ClCN losses during long-term preservation with excess reducing sulfur compounds prior to analysis can be substantial and should be avoided.

  1. Next generation chemical proteomic tools for rapid enzyme profiling.

    Science.gov (United States)

    Uttamchandani, Mahesh; Lu, Candy H S; Yao, Shao Q

    2009-08-18

    Sequencing of the human genome provided a wealth of information about the genomic blueprint of a cell. But genes do not tell the entire story of life and living processes; identifying the roles of enzymes and mapping out their interactions is also crucial. Enzymes catalyze virtually every cellular process and metabolic exchange. They not only are instrumental in sustaining life but also are required for its regulation and diversification. Diseases such as cancer can be caused by minor changes in enzyme activities. In addition, the unique enzymes of pathogenic organisms are ripe targets for combating infections. Consequently, nearly one-third of all current drug targets are enzymes. An estimated 18-29% of eukaryotic genes encode enzymes, but only a limited proportion of enzymes have thus far been characterized. Therefore, little is understood about the physiological roles, substrate specificity, and downstream targets of the vast majority of these important proteins. A key step toward the biological characterization of enzymes, as well as their adoption as drug targets, is the development of global solutions that bridge the gap in understanding these proteins and their interactions. We herein present technological advances that facilitate the study of enzymes and their properties in a high-throughput manner. Over the years, our group has introduced and developed a variety of such enabling platforms for many classes of enzymes, including kinases, phosphatases, and proteases. For each of these different types of enzymes, specific design considerations are required to develop the appropriate chemical tools to characterize each class. These tools include activity-based probes and chemical compound libraries, which are rapidly assembled using efficient combinatorial synthesis or "click chemistry" strategies. The resulting molecular assortments may then be screened against the target enzymes in high-throughput using microplates or microarrays. These techniques offer

  2. Drag reduction of a rapid vehicle in supercavitating flow

    Directory of Open Access Journals (Sweden)

    D. Yang

    2017-01-01

    Full Text Available Supercavitation is one of the most attractive technologies to achieve high speed for underwater vehicles. However, the multiphase flow with high-speed around the supercavitating vehicle (SCV is difficult to simulate accurately. In this paper, we use modified the turbulent viscosity formula in the Standard K-Epsilon (SKE turbulent model to simulate the supercavitating flow. The numerical results of flow over several typical cavitators are in agreement with the experimental data and theoretical prediction. In the last part, a flying SCV was studied by unsteady numerical simulation. The selected computation setup corresponds to an outdoor supercavitating experiment. Only very limited experimental data was recorded due to the difficulties under the circumstance of high-speed underwater condition. However, the numerical simulation recovers the whole scenario, the results are qualitatively reasonable by comparing to the experimental observations. The drag reduction capacity of supercavitation is evaluated by comparing with a moving vehicle launching at the same speed but without supercavitation. The results show that the supercavitation reduces the drag of the vehicle dramatically.

  3. Rapid determination of fumigant and industrial chemical residues in food.

    Science.gov (United States)

    Daft, J L

    1988-01-01

    A gas chromatographic (GC) method is described for the determination of 22 fumigant and industrial chemical residues in a variety of foods. The fumigants and industrial chemicals determined are methyl bromide, methylene chloride, carbon disulfide, chloroform, 1,1-dichloroethane, ethylene dichloride, methyl chloroform, carbon tetrachloride, methylene bromide, propylene dichloride, 2,3-dichloropropene, trichloroethylene, 1,3-dichloropropylene, 1,1,2-trichloroethane, chloropicrin, ethylene dibromide, tetrachloroethylene, propylene dibromide, 1,1,2,2-tetrachloroethane, p-dichlorobenzene, o-dichlorobenzene, and 1,2-dibromo-3-chloropropane. Except for the latter three, the fumigants are determined at 90 degrees C on 3.6 m 20% loaded OV-101 columns with electron-capture and Hall-electroconductivity detectors. The other 3 compounds (o-dichlorobenzene, p-dichlorobenzene, and 1,2-dibromo-3-chloropropane), which elute beyond 30 min on the above columns, are determined at 90 degrees C on 1.8 m 5% loaded OV-101 columns with the same detectors. The ng/g-level fortifications have an overall mean analyte recovery of 70% and a coefficient of variation of 40%. The variety of foods examined includes both fatty and nonfatty food types (e.g., off-the-shelf cooked and uncooked grain-based items, dairy products, fresh and canned fruits and vegetables, and meats). Samples are extracted and cleaned up according to fat content and food type. Samples containing less than 71% fat are extracted by using an aqueous: nonaqueous shakeout (20% acetone solution under isooctane). Most extracts (isooctanes) are analyzed directly. Extracts from samples containing from 21 to 70% fat (e.g., ground beef, pecans, and corn chips) are cleaned up further on micro-Florisil columns to remove excess fat. A few other samples containing more than 71% fat or oil (e.g., butter, salad dressing, and vegetable oil) are diluted directly in isooctane and, depending on the degree of dilution, can be cleaned up further on

  4. Modifier effects on chemical reduction synthesis of nanostructured copper

    Science.gov (United States)

    Cheng, Xiaonong; Zhang, Xifeng; Yin, Hengbo; Wang, Aili; Xu, Yiqing

    2006-12-01

    Size-controlled chemical reduction synthesis of nanostructured Cu was studied in the presence of a single modifier such as polyethylene glycols, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate or a mixture of two different types of modifiers. The Cu nanoparticles were characterized by powder X-ray diffraction, transmission electron microscopy, selected area electron diffraction and Fourier transform infrared spectroscopy. The average particle size and particle size distribution of the nanostructured Cu depend upon the type of modifiers and the modifier effect follows the order: PEG-2000 > SDBS > PEG-600 > SDS > PEG-6000. The experimental results indicate that due to the existence of a synergistic action, a mixture of two types of modifiers has a significant effect on the particle size and the size distribution of Cu nanoparticles.

  5. Modifier effects on chemical reduction synthesis of nanostructured copper

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Xiaonong [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhang Xifeng [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)]. E-mail: zhangxf_chzh@163.com; Yin Hengbo [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang Aili [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Xu Yiqing [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2006-12-30

    Size-controlled chemical reduction synthesis of nanostructured Cu was studied in the presence of a single modifier such as polyethylene glycols, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate or a mixture of two different types of modifiers. The Cu nanoparticles were characterized by powder X-ray diffraction, transmission electron microscopy, selected area electron diffraction and Fourier transform infrared spectroscopy. The average particle size and particle size distribution of the nanostructured Cu depend upon the type of modifiers and the modifier effect follows the order: PEG-2000 > SDBS > PEG-600 > SDS > PEG-6000. The experimental results indicate that due to the existence of a synergistic action, a mixture of two types of modifiers has a significant effect on the particle size and the size distribution of Cu nanoparticles.

  6. Sulfa Drugs Inhibit Sepiapterin Reduction and Chemical Redox Cycling by Sepiapterin Reductase

    Science.gov (United States)

    Yang, Shaojun; Jan, Yi-Hua; Mishin, Vladimir; Richardson, Jason R.; Hossain, Muhammad M.; Heindel, Ned D.; Heck, Diane E.; Laskin, Debra L.

    2015-01-01

    Sepiapterin reductase (SPR) catalyzes the reduction of sepiapterin to dihydrobiopterin (BH2), the precursor for tetrahydrobiopterin (BH4), a cofactor critical for nitric oxide biosynthesis and alkylglycerol and aromatic amino acid metabolism. SPR also mediates chemical redox cycling, catalyzing one-electron reduction of redox-active chemicals, including quinones and bipyridinium herbicides (e.g., menadione, 9,10-phenanthrenequinone, and diquat); rapid reaction of the reduced radicals with molecular oxygen generates reactive oxygen species (ROS). Using recombinant human SPR, sulfonamide- and sulfonylurea-based sulfa drugs were found to be potent noncompetitive inhibitors of both sepiapterin reduction and redox cycling. The most potent inhibitors of sepiapterin reduction (IC50s = 31–180 nM) were sulfasalazine, sulfathiazole, sulfapyridine, sulfamethoxazole, and chlorpropamide. Higher concentrations of the sulfa drugs (IC50s = 0.37–19.4 μM) were required to inhibit redox cycling, presumably because of distinct mechanisms of sepiapterin reduction and redox cycling. In PC12 cells, which generate catecholamine and monoamine neurotransmitters via BH4-dependent amino acid hydroxylases, sulfa drugs inhibited both BH2/BH4 biosynthesis and redox cycling mediated by SPR. Inhibition of BH2/BH4 resulted in decreased production of dopamine and dopamine metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, and 5-hydroxytryptamine. Sulfathiazole (200 μM) markedly suppressed neurotransmitter production, an effect reversed by BH4. These data suggest that SPR and BH4-dependent enzymes, are “off-targets” of sulfa drugs, which may underlie their untoward effects. The ability of the sulfa drugs to inhibit redox cycling may ameliorate ROS-mediated toxicity generated by redox active drugs and chemicals, contributing to their anti-inflammatory activity. PMID:25550200

  7. Rapid mixing chemical oxidative polymerization: an easy route to ...

    Indian Academy of Sciences (India)

    Administrator

    (catalyst)-coated silicon wafer was used as the substrate. After placing the substrate in the furnace of the .... monomer. This type of interaction is evident from Raman analysis (red shift in C=N Raman band corresponding to. PANI). Remaining aniline molecules get dispersed in the aq. HCl suspension. At the moment of rapid ...

  8. Rapid neutron capture process in supernovae and chemical element formation

    NARCIS (Netherlands)

    Baruah, Rulee; Duorah, Kalpana; Duorah, H. L.

    2009-01-01

    The rapid neutron capture process (r-process) is one of the major nucleosynthesis processes responsible for the synthesis of heavy nuclei beyond iron. Isotopes beyond Fe are most exclusively formed in neutron capture processes and more heavier ones are produced by the r-process. Approximately half

  9. Experimental setup for rapid crystallization using favoured chemical ...

    Indian Academy of Sciences (India)

    Unknown

    tors (3005 type), the output of which drives the d.c. motor. M3. The solution of ... to motor M1 prevents rapid temperature fluctuations and hence ensures very good temperature control. The thermostatic bath is heated with an infrared lamp I at the base of the unit and ... through chains of hydrogen bonds and these polymers.

  10. Experimental setup for rapid crystallization using favoured chemical ...

    Indian Academy of Sciences (India)

    The rapid crystallization of KH2PO4 (KDP) from solution is demonstrated at a rate up to ≈7.5 mm/day along [100] and 22 mm/day along [001] in a crystallizer of 5 l capacity, using accelerated crucible rotation technique (ACRT) and simulated platform geometry for controlling the hydrodynamic conditions. On an experimental ...

  11. A Rapid Compression Expansion Machine (RCEM) for studying chemical kinetics: Experimental principle and first applications

    CERN Document Server

    Werler, Marc; Maas, Ulrich

    2016-01-01

    A novel extension of a rapid compression machine (RCM), namely a Rapid Compression Expansion Machine (RCEM), is described and its use for studying chemical kinetics is demonstrated. Like conventional RCMs, the RCEM quickly compresses a fuel/air mixture by pushing a piston into a cylinder; the resulting high temperatures and pressures initiate chemical reactions. In addition, the machine can rapidly expand the compressed gas in a controlled way by pulling the piston outwards again. This freezes chemical activity after a pre-defined reaction duration, and therefore allows a convenient probe sampling and ex-situ gas analysis of stable species. The RCEM therefore is a promising instrument for studying chemical kinetics, including also partially reacted fuel/air mixtures. The setup of the RCEM, its experimental characteristics and its use for studying chemical reactions are outlined in detail. To allow comparisons of RCEM results with predictions of chemical reaction mechanisms, a simple numerical model of the RCE...

  12. Laccase-Assisted Rapid Synthesis of Colloidal Gold Nanoparticles for the Catalytic Reduction of 4-Nitrophenol

    OpenAIRE

    Li, Fang; Li, Zheng; Zeng, Chang; Hu, Yonggang

    2017-01-01

    A green method for the rapid preparation of uniform-sized colloidal gold nanoparticles under ambient conditions was presented and validated using laccase as a reduction agent in alkaline medium. UV-Vis spectrophotometry, field-emission high-resolution transmission electron microscopy, X-ray diffraction, selected area electron diffraction, energy dispersive X-ray analysis, zetasizer, and Fourier transform infrared spectroscopy were used to characterize the gold nanoparticles. The gold nanopart...

  13. Evaluation and Development of Chemical Kinetic Mechanism Reduction Scheme for Biodiesel and Diesel Fuel Surrogates

    DEFF Research Database (Denmark)

    Poon, Hiew Mun; Ng, Hoon Kiat; Gan, Suyin

    2013-01-01

    The aim of this study is to evaluate the existing chemical kinetic mechanism reduction techniques. From here, an appropriate reduction scheme was developed to create compact yet comprehensive surrogate models for both diesel and biodiesel fuels for diesel engine applications. The reduction techni...

  14. A modified MS2 bacteriophage plaque reduction assay for the rapid screening of antiviral plant extracts.

    Science.gov (United States)

    Cock, Ian; Kalt, F R

    2010-07-01

    Traditional methods of screening plant extracts and purified components for antiviral activity require up to a week to perform, prompting the need to develop more rapid quantitative methods to measure the ability of plant based preparations to block viral replication. We describe an adaption of an MS2 plaque reduction assay for use in S. aureus. MS2 bacteriophage was capable of infecting and replicating in B. cereus, S. aureus and F + E. coli but not F- E. coli. Indeed, both B. cereus and S. aureus were more sensitive to MS2 induced lysis than F+ E. coli. When MS2 bacteriophage was mixed with Camellia sinensis extract (1 mg/ml), Scaevola spinescens extract (1 mg/ml) or Aloe barbadensis juice and the mixtures inoculated into S. aureus, the formation of plaques was reduced to 8.9 ± 3.8%, 5.4 ± 2.4% and 72.7 ± 20.9% of the untreated MS2 control values respectively. The ability of the MS2 plaque reduction assay to detect antiviral activity in these known antiviral plant preparations indicates its suitability as an antiviral screening tool. An advantage of this assay compared with traditionally used cytopathic effect reduction assays and replicon based assays is the more rapid acquisition of results. Antiviral activity was detected within 24 h of the start of testing. The MS2 assay is also inexpensive and non-pathogenic to humans making it ideal for initial screening studies or as a simulant for pathogenic viruses.

  15. Development and Validation of Chemical Kinetic Mechanism Reduction Scheme for Large-Scale Mechanisms

    DEFF Research Database (Denmark)

    Poon, Hiew Mun; Ng, Hoon Kiat; Gan, Suyin

    2014-01-01

    This work is an extension to a previously reported work on chemical kinetic mechanism reduction scheme for large-scale mechanisms. Here, Perfectly Stirred Reactor (PSR) was added as a criterion of data source for mechanism reduction instead of using only auto-ignition condition. As a result, a re...

  16. Rapid chemical and topological ordering in supercooled liquid Cu46Zr54

    Science.gov (United States)

    Wessels, V.; Gangopadhyay, A. K.; Sahu, K. K.; Hyers, R. W.; Canepari, S. M.; Rogers, J. R.; Kramer, M. J.; Goldman, A. I.; Robinson, D.; Lee, J. W.; Morris, J. R.; Kelton, K. F.

    2011-03-01

    Evidence for rapid ordering in a supercooled Cu46Zr54 liquid, obtained from high-energy x-ray diffraction in a containerless processing environment, is presented. Relatively sudden changes were observed in the topological and chemical short-range order near 850 °C, a temperature that is 75 °C below the liquidus temperature and 465 °C above the glass transition temperature. A peak in the specific heat was observed with supercooling, with an onset near 850 °C (the same temperature as the onset of ordering) and a maximum near 700 °C, consistent with the prediction of a molecular-dynamics calculation using embedded atom potentials. The chemical and topological ordering measured here are in agreement with predictions of a rapid development of chemically ordered icosahedral clusters in the supercooled liquid.

  17. Preparation and characterization of silver nanoparticles by chemical reduction method.

    Science.gov (United States)

    Khan, Zaheer; Al-Thabaiti, Shaeel Ahmed; Obaid, Abdullah Yousif; Al-Youbi, A O

    2011-02-01

    Silver nanoparticles were prepared by the reduction of AgNO(3) with aniline in dilute aqueous solutions containing cetyltrimethlyammonium bromide, CTAB. Nanoparticles growth was assessed by UV-vis spectroscopy and the average particle size and the size distribution were determined from transmission electron microscopy, TEM. As the reaction proceeds, a typical plasmon absorption band at 390-450nm appears for the silver nanoparticles and the intensities increase with the time. Effects of [aniline], [CTAB] and [Ag(+)] on the particle formation rate were analyzed. The apparent rate constants for the formation of silver nanoparticles first increased until it reached a maximum then decreased with [aniline]. TEM photographs indicate that the silver sol consist of well dispersed agglomerates of spherical shape nanoparticles with particle size range from 10 to 30nm. Aniline concentrations have no significant effect on the shape, size and the size distribution of Ag-nanoparticles. Aniline acts as a reducing as well as adsorbing agent in the preparation of roughly spherical, agglomerated and face-centered-cubic silver nanoparticles. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Integrase inhibitors in late pregnancy and rapid HIV viral load reduction.

    Science.gov (United States)

    Rahangdale, Lisa; Cates, Jordan; Potter, JoNell; Badell, Martina L; Seidman, Dominika; Miller, Emilly S; Coleman, Jenell S; Lazenby, Gweneth B; Levison, Judy; Short, William R; Yawetz, Sigal; Ciaranello, Andrea; Livingston, Elizabeth; Duthely, Lunthita; Rimawi, Bassam H; Anderson, Jean R; Stringer, Elizabeth M

    2016-03-01

    Minimizing time to HIV viral suppression is critical in pregnancy. Integrase strand transfer inhibitors (INSTIs), like raltegravir, are known to rapidly suppress plasma HIV RNA in nonpregnant adults. There are limited data in pregnant women. We describe time to clinically relevant reduction in HIV RNA in pregnant women using INSTI-containing and non-INSTI-containing antiretroviral therapy (ART) options. We conducted a retrospective cohort study of pregnant HIV-infected women in the United States from 2009 through 2015. We included women who initiated ART, intensified their regimen, or switched to a new regimen due to detectable viremia (HIV RNA >40 copies/mL) at ≥20 weeks gestation. Among women with a baseline HIV RNA permitting 1-log reduction, we estimated time to 1-log RNA reduction using the Kaplan-Meier estimator comparing women starting/adding an INSTI in their regimen vs other ART. To compare groups with similar follow-up time, we also conducted a subgroup analysis limited to women with ≤14 days between baseline and follow-up RNA data. This study describes 101 HIV-infected pregnant women from 11 US clinics. In all, 75% (76/101) of women were not taking ART at baseline; 24 were taking non-INSTI containing ART, and 1 received zidovudine monotherapy. In all, 39% (39/101) of women started an INSTI-containing regimen or added an INSTI to their ART regimen. Among 90 women with a baseline HIV RNA permitting 1-log reduction, the median time to 1-log RNA reduction was 8 days (interquartile range [IQR], 7-14) in the INSTI group vs 35 days (IQR, 20-53) in the non-INSTI ART group (P pregnancy. Inclusion of an INSTI may play a role in optimal reduction of HIV RNA for HIV-infected pregnant women presenting late to care or failing initial therapy. Larger studies are urgently needed to assess the safety and effectiveness of this approach. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. RAPID EXPOSURE ASSESSMENT OF NATIONWIDE RIVER FLOOD FOR DISASTER RISK REDUCTION

    Directory of Open Access Journals (Sweden)

    Y. Kwak

    2016-06-01

    Full Text Available considerably increased. For flood disaster risk reduction, it is important to identify and characterize flood area, locations (particularly lowland along rivers, and durations. For this purpose, flood mapping and monitoring are an imperative process and the fundamental part of risk management as well as emergency response. Our ultimate goal is to detect flood inundation areas over a nationwide scale despite limitations of optical and multispectral images, and to estimate flood risk in terms of affected people. We propose a methodological possibility to be used as a standard approach for nationwide rapid flood exposure assessment with the use of the multi-temporal Moderate Resolution Imaging Spectrometer (MODIS, a big contributor to progress in near-real-time flood mapping. The preliminary results in Bangladesh show that a propensity of flood risk change strongly depends on the temporal and spatial dynamics of exposure such as distributed population.

  20. Rapid and Sensitive Reporter Gene Assays for Detection of Antiandrogenic and Estrogenic Effects of Environmental Chemicals

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Bonefeld-Jørgensen, Eva Cecilie; Larsen, John Christian

    1999-01-01

    Reports on increasing incidences in developmental abnormalities of the human male reproductive tract and the recent identifications of environmental chemicals with antiandrogenic activity necessitate the screening of a larger number of compounds in order to get an overview of potential...... antiandrogenic chemicals present in our environment. Thus, there is a great need for an effectivein vitroscreening method for (anti)androgenic chemicals. We have developed a rapid, sensitive, and reproducible reporter gene assay for detection of antiandrogenic chemicals. Chinese Hamster Ovary cells were......-on laboratory time. This assay is a powerful tool for the efficient and accurate determination and quantification of the effects of antiandrogens on reporter gene transcription. To extend the application of FuGene, the reagent was shown to be superior compared to Lipofectin for transfecting MCF7 human breast...

  1. Rapid Prototyping of Chemical Microsensors Based on Molecularly Imprinted Polymers Synthesized by Two-Photon Stereolithography.

    Science.gov (United States)

    Gomez, Laura Piedad Chia; Spangenberg, Arnaud; Ton, Xuan-Anh; Fuchs, Yannick; Bokeloh, Frank; Malval, Jean-Pierre; Tse Sum Bui, Bernadette; Thuau, Damien; Ayela, Cédric; Haupt, Karsten; Soppera, Olivier

    2016-07-01

    Two-photon stereolithography is used for rapid prototyping of submicrometre molecularly imprinted polymer-based 3D structures. The structures are evaluated as chemical sensing elements and their specific recognition properties for target molecules are confirmed. The 3D design capability is exploited and highlighted through the fabrication of an all-organic molecularly imprinted polymeric microelectromechanical sensor. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Rapid detection of chemical hazards (toxins, dioxins, and PCBs) in seafood.

    Science.gov (United States)

    Arvanitoyannis, Ioannis S; Kotsanopoulos, Konstantinos V; Papadopoulou, Anna

    2014-01-01

    Among the various hazards occurring in fish and seafood chemical hazards and in particular toxins (ciguatera, scombroid fish poisoning, paralytic shellfish poisoning, neurotoxic (brevetoxic) shellfish poisoning, puffer fish poisoning, diarrhetic shellfish poisoning) have an important place in food poisoning cases. On the other hand, some of the chemical hazards are often due to the pollution of the environment (heavy metals, dioxins, polychlorinated biphenyls, and halogenated aromatic hydrocarbons) and their detection is neither rapid nor facile. As a result there was a great need for developing new rapid and effective methods toward the chemical hazards determination mainly because of their high toxicity. The aim of this review is to provide the information about the new up-to-date detection techniques (Immunological, Chemical and Biochemical, and Molecular assays) in conjunction with detection limits. The latter is made possible by means of inclusion of seven comprehensive and, in most case cases, very extended tables. A reference is also made on the risk characterization of toxins as regards their importance to food contamination or poisoning.

  3. Development of a New Decision Tree to Rapidly Screen Chemical Estrogenic Activities of Xenopus laevis.

    Science.gov (United States)

    Wang, Ting; Li, Weiying; Zheng, Xiaofeng; Lin, Zhifen; Kong, Deyang

    2014-02-01

    During the last past decades, there is an increasing number of studies about estrogenic activities of the environmental pollutants on amphibians and many determination methods have been proposed. However, these determination methods are time-consuming and expensive, and a rapid and simple method to screen and test the chemicals for estrogenic activities to amphibians is therefore imperative. Herein is proposed a new decision tree formulated not only with physicochemical parameters but also a biological parameter that was successfully used to screen estrogenic activities of the chemicals on amphibians. The biological parameter, CDOCKER interaction energy (Ebinding ) between chemicals and the target proteins was calculated based on the method of molecular docking, and it was used to revise the decision tree formulated by Hong only with physicochemical parameters for screening estrogenic activity of chemicals in rat. According to the correlation between Ebinding of rat and Xenopus laevis, a new decision tree for estrogenic activities in Xenopus laevis is finally proposed. Then it was validated by using the randomly 8 chemicals which can be frequently exposed to Xenopus laevis, and the agreement between the results from the new decision tree and the ones from experiments is generally satisfactory. Consequently, the new decision tree can be used to screen the estrogenic activities of the chemicals, and combinational use of the Ebinding and classical physicochemical parameters can greatly improves Hong's decision tree. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Rapid and sensitive reporter gene assays for detection of antiandrogenic and estrogenic effects of environmental chemicals

    DEFF Research Database (Denmark)

    Vinggaard, Anne; Jørgensen, E.C.B.; Larsen, John Christian

    1999-01-01

    antiandrogenic chemicals present in our environment. Thus, there is a great need for an effective in vitro screening method for (anti)androgenic chemicals. We have developed a rapid, sensitive, and reproducible reporter gene assay for detection of antiandrogenic chemicals. Chinese Hamster Ovary cells were...... induction of luciferase activity. The classical antiandrogenic compounds hydroxy-flutamide, bicalutamide, spironolactone, and cyproterone acetate together with the pesticide(metabolite)s, vinclozolin, p,p'-DDE, and procymidone all potently inhibited the response to 0.1 nM R1881, Compared to the traditional...... cancer cells with an estrogen response element-luciferase vector. Thus, FuGene may prove to be valuable in diverse reporter gene assays involving transient transfections for screening of potential endocrine disrupters for (anti)androgenic and (anti)estrogenic properties....

  5. Reduction Kinetics of a CasO4 Based Oxygen Carrier for Chemical-Looping Combustion

    Science.gov (United States)

    Xiao, R.; Song, Q. L.; Zheng, W. G.; Deng, Z. Y.; Shen, L. H.; Zhang, M. Y.

    The CaSO4 based oxygen carrier has been proposed as an alternative low cost oxygen carrier for Chemical-looping combustion (CLC) of coal. The reduction of CaSO4 to CaS is an important step for the cyclic process of reduction/oxidation in CLC of coal with CaSO4 based oxygen carrier. Thermodynamic analysis of CaSO4 oxygen carrier with CO based on the principle of Gibbs free energy minimization show that the essentially high purity of CO2 can be obtained, while the solid product is CaS instead of CaO. The intrinsic reduction kinetics of a CaSO4 based oxygen carrier with CO was investigated in a differential fixed bed reactor. The effects of gas partial pressure (20%-70%) and temperature (880-950°C) on the reduction were investigated. The reduction was described with shrinking unreacted core model. Experimental results of CO partial pressure on the solid conversion show that the reduction of fresh oxygen carriers is of first order with respect to the CO partial pressure. Both chemical reaction control and product layer diffusion control determine the reduction rate. The dependences of reaction rate constant and effective diffusivity with temperature were both obtained. The kinetic equation well predicted the experimental data.

  6. Quantum chemical analysis of Со2+ aqua complexes electrochemical reduction

    Directory of Open Access Journals (Sweden)

    Viktor F. Vargalyuk

    2017-11-01

    Full Text Available Based on the analysis of quantum chemical calculations results (GAMESS, density functional theory, B3LYP method as to [Co(H2On]z(H2O6–n clusters for z = 0, 1, 2 and n=1÷6, it has been demonstrated that electrochemical reduction of [Co(H2O6]2+ aqua complexes runs stage-wise. At the first stage, an electron injected into the [Co(H2O6]2+ complex is entirely located in the orbital of the central atom, as z(Co herewith changes from +1.714 е to +0.777 е. The weakening of Со–ОН2 bonds leads to decomposition of resulting [Co(H2O6]+ particles into two energetically related forms – [Co(H2O4]+ and [Co(H2O3]+. Further reduction of these intermediates runs differently. Electron injection into the [Co(H2O3]+ intermediate terminatesthe transition of Со2+-ions to Со0 z(Co= –0.264 е. This process is accompanied by rapid decomposition of [Co(H2O3]0 product into monohydrate atom of cobalt Со(Н2О. On the contrary, electron injection into the [Co(H2O4]+ intermediate leads to emergence of a specific structure – [Co+(H2O–(Н2О3]¹0, whereby the electron is located in the atoms of cobalt only by 28%, and by 72% in cobalt-coordinated water molecules, clearly focusing on one of the. In this molecule, z(H2O changes from +0.148 е to –0.347 е. There is an assumption that a non-equilibrium [Co+(H2O–(Н2О3]0¹ form transits to [Co(ОH(Н2О3]0 hydroxo-form, which further disproportionates turning into Co(ОH2 hydroxide. In order to reduce the impact of this unfavorable reaction pathway on the overall reaction rate Со2+ + 2ē = Со0, we suggest raising the temperature to ensure complete dissociation of [Co(H2O4]+ to [Co(H2O3]+.

  7. Rapid chemical shift encoding with single-acquisition single-slab 3D GRASE.

    Science.gov (United States)

    Kim, Hahnsung; Kim, Dong-Hyun; Sohn, Chul-Ho; Park, Jaeseok

    2017-11-01

    To investigate the feasibility of chemical shift encoded, single-slab 3D GRASE for rapid fat-water separation within a single acquisition. The proposed method incorporates signal-to-noise-ratio-optimal chemical shift encoding into single-slab 3D GRASE with variable flip angles. Chemical shift induced phase information was encoded in succession to different positions in k-space by inserting phase encoding blips between adjacent lobes of the oscillating readout gradients. To enhance imaging efficiency, signal prescription-based variable flip angles were used in the long refocusing pulse train. After echo-independent phase correction, missing signals in k-echo space were interpolated using convolution kernels that span over all echoes. Fat-water separation in a single acquisition was performed using both multi-echo fast spin echo and GRASE as compared to conventional multiacquisition fast spin echo with echo shifts. The proposed single-slab 3D GRASE shows superior performance in accurately delineating cartilage structures compared to its counterpart, multi-echo 3D fast spin echo. Compared with multiacquisition fast spin echo with three echo shifts (63 min), the proposed method substantially speeds up imaging time (7 min), and achieves 0.6 mm isotropic resolution in knee imaging with reduced artifacts and noise. We successfully demonstrated the feasibility of rapid chemical shift encoding and separation using the proposed, single-acquisition single-slab 3D GRASE for high resolution isotropic imaging within clinically acceptable time. Magn Reson Med 78:1852-1861, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Large area super-resolution chemical imaging via rapid dithering of a nanoprobe

    Science.gov (United States)

    Languirand, Eric R.; Cullum, Brian M.

    2015-05-01

    Super-resolution chemical imaging via Raman spectroscopy provides a significant ability to simultaneously or pseudosimultaneously monitor numerous label-free analytes while elucidating their spatial distribution on the surface of the sample. However, spontaneous Raman is an inherently weak phenomenon making trace detection and thus superresolution imaging extremely difficult, if not impossible. To circumvent this and allow for trace detection of the few chemical species present in any sub-diffraction limited resolution element of an image, we have developed a surface enhanced Raman scattering (SERS) coherent fiber-optic imaging bundle probe consisting of 30,000 individual fiber elements. When the probes are tapered, etched and coated with metal, they provide circular Raman chemical images of a sample with a field of view of approximately 20μm (i.e. diameter) via the array of 30,000 individual 50 nm fiber elements. An acousto-optic tunable filter is used to rapidly scan or select discrete frequencies for multi- or hyperspectral analysis. Although the 50nm fiber element dimensions of this probe inherently provide spatial resolutions of approximately 100nm, further increases in the spatial resolution can be achieved by using a rapid dithering process. Using this process, additional images are obtained one-half fiber diameter translations in the x- and y- planes. A piezostage drives the movement, providing the accurate and reproducible shifts required for dithering. Optimal probability algorithms are then used to deconvolute the related images producing a final image with a three-fold increase in spatial resolution. This paper describes super-resolution chemical imaging using these probes and the dithering method as well as its potential applications in label-free imaging of lipid rafts and other applications within biology and forensics.

  9. Rapid Electrochemical Detection and Identification of Microbiological and Chemical Contaminants for Manned Spaceflight Project

    Science.gov (United States)

    Pierson, Duane; Botkin, Douglas; Gazda, Daniel

    2014-01-01

    Microbial control in the spacecraft environment is a daunting task, especially in the presence of human crew members. Currently, assessing the potential crew health risk associated with a microbial contamination event requires return of representative environmental samples that are analyzed in a ground-based laboratory. It is therefore not currently possible to quickly identify microbes during spaceflight. This project addresses the unmet need for spaceflight-compatible microbial identification technology. The electrochemical detection and identification platform is expected to provide a sensitive, specific, and rapid sample-to-answer capability for in-flight microbial monitoring that can distinguish between related microorganisms (pathogens and non-pathogens) as well as chemical contaminants. This will dramatically enhance our ability to monitor the spacecraft environment and the health risk to the crew. Further, the project is expected to eliminate the need for sample return while significantly reducing crew time required for detection of multiple targets. Initial work will focus on the optimization of bacterial detection and identification. The platform is designed to release nucleic acids (DNA and RNA) from microorganisms without the use of harmful chemicals. Bacterial DNA or RNA is captured by bacteria-specific probe molecules that are bound to a microelectrode, and that capture event can generate a small change in the electrical current (Lam, et al. 2012. Anal. Chem. 84(1): 21-5.). This current is measured, and a determination is made whether a given microbe is present in the sample analyzed. Chemical detection can be accomplished by directly applying a sample to the microelectrode and measuring the resulting current change. This rapid microbial and chemical detection device is designed to be a low-cost, low-power platform anticipated to be operated independently of an external power source, characteristics optimal for manned spaceflight and areas where power

  10. Bleach Plant Capital Reduction with Rapid DO Bleaching and Simplified (D/E/D) Stages

    Energy Technology Data Exchange (ETDEWEB)

    T. J. McDonough; C. E. Courchene; J-C. Baromes

    2000-08-01

    The objective of this work was to demonstrate the capabilities of a bleaching sequence that combined a short retention time initial chlorine dioxide stage, referred to as rapid D0, (D0R), with simplified bleaching stages, (D1/E/D2), that required only one final bleach washer. The test sequence DR(EPO)(D/E/D/) was compared to a control sequence, D(EPO)D, for both hardwood and softwood pulps. The capabilities of the DR(EPO)(D/E/D) sequence were successfully demonstrated. An existing three- or four-stage bleach plan can be converted to the more powerful DR(EPO)(D/E/D) sequence without the major capital cost of additional washers. The results from this study showed that the DR(EPO)(D/E/D) sequence can reach 85 brightness on SW with 2.8% total C1O2, while the control sequence, D(EPO)D, required 3.9% C1O2. There was a corresponding decrease in AOX for the test sequence. The strength of pulp bleached in the test sequence was similar to or slightly higher than the control. For the HW pu lp, the test sequence reached 88 brightness with 2.2% C1O2 compared to 3.3% C1O2 for the control. There was a corresponding decrease in AOX generation with the lower chemical requirements. The final viscosity and pulp strength for the test sequence on HW was significantly higher than the corresponding values for the control sequence.

  11. Chemical and enzymatic reductive activation of acylfulvene to isomeric cytotoxic reactive intermediates.

    Science.gov (United States)

    Pietsch, Kathryn E; Neels, James F; Yu, Xiang; Gong, Jiachang; Sturla, Shana J

    2011-11-21

    Acylfulvenes (AFs), a class of semisynthetic analogues of the sesquiterpene natural product illudin S, are cytotoxic toward cancer cells. The minor structural changes between illudin S and AFs translate to an improved therapeutic window in preclinical cell-based assays and xenograft models. AFs are, therefore, unique tools for addressing the chemical and biochemical basis of cytotoxic selectivity. AFs elicit cytotoxic responses by alkylation of biological targets, including DNA. While AFs are capable of direct alkylation, cytosolic reductive bioactivation to an electrophilic intermediate is correlated with enhanced cytotoxicity. Data obtained in this study illustrate chemical aspects of the process of AF activation. By tracking reaction mechanisms with stable isotope-labeled reagents, enzymatic versus chemical activation pathways for AF were compared for reactions involving the NADPH-dependent enzyme prostaglandin reductase 1 (PTGR1) or sodium borohydride, respectively. These two processes resulted in isomeric products that appear to give rise to similar patterns of DNA modification. The chemically activated isomer has been newly isolated and chemically characterized in this study, including an assessment of its relative stereochemistry and stability at varying pH and under bioassay conditions. In mammalian cancer cells, this chemically activated analogue was shown to not rely on further cellular activation to significantly enhance cytotoxic potency, in contrast to the requirements of AF. On the basis of this study, we anticipate that the chemically activated form of AF will serve as a useful chemical probe for evaluating biomolecular interactions independent of enzyme-mediated activation.

  12. Technology Roadmap: Energy and GHG reductions in the chemical industry via catalytic processes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-01

    The chemical industry is a large energy user; but chemical products and technologies also are used in a wide array of energy saving and/or renewable energy applications so the industry has also an energy saving role. The chemical and petrochemical sector is by far the largest industrial energy user, accounting for roughly 10% of total worldwide final energy demand and 7% of global GHG emissions. The International Council of Chemical Associations (ICCA) has partnered with the IEA and DECHEMA (Society for Chemical Engineering and Biotechnology) to describe the path toward further improvements in energy efficiency and GHG reductions in the chemical sector. The roadmap looks at measures needed from the chemical industry, policymakers, investors and academia to press on with catalysis technology and unleash its potential around the globe. The report uncovers findings and best practice opportunities that illustrate how continuous improvements and breakthrough technology options can cut energy use and bring down greenhouse gas (GHG) emission rates. Around 90% of chemical processes involve the use of catalysts – such as added substances that increase the rate of reaction without being consumed by it – and related processes to enhance production efficiency and reduce energy use, thereby curtailing GHG emission levels. This work shows an energy savings potential approaching 13 exajoules (EJ) by 2050 – equivalent to the current annual primary energy use of Germany.

  13. In-situ chemical reduction produced graphene paper for flexible supercapacitors with impressive capacitive performance

    Science.gov (United States)

    Ye, Xingke; Zhu, Yucan; Tang, Zhonghua; Wan, Zhongquan; Jia, Chunyang

    2017-08-01

    For practical applications of graphene-based materials in flexible supercapacitors, a technological breakthrough is currently required to fabricate high-performance graphene paper by a facile method. Herein, highly conductive (∼6900 S m-1) graphene paper with loose multilayered structure is produced by a high-efficiency in-situ chemical reduction process, which assembles graphite oxide suspensions into film and simultaneously conducts chemical reduction. Graphene papers with different parameters (including different types and doses of reductants, different thicknesses and areas of films) are successfully fabricated through this in-situ chemical reduction method. Meanwhile, the influences of the graphene papers with different parameters upon the supercapacitor performance are systematically investigated. Flexible supercapacitor based on the graphene paper exhibits high areal capacitance (152.4 mF cm-2 at current density of 2.0 mA cm-2 in aqueous electrolyte), and excellent rate performance (88.7% retention at 8.0 mA cm-2). Furthermore, bracelet-shaped all-solid supercapacitor with fascinating cycling stability (96.6% retention after 10 000 cycles) and electrochemical stability (an almost negligible capacity loss under different bending states and 99.6% retention after 4000 bending cycles) is established by employing the graphene paper electrode material and polymer electrolyte.

  14. Development Of Chemical Reduction And Air Stripping Processes To Remove Mercury From Wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Dennis G.; Looney, Brian B.; Craig, Robert R.; Thompson, Martha C.; Kmetz, Thomas F.

    2013-07-10

    This study evaluates the removal of mercury from wastewater using chemical reduction and air stripping using a full-scale treatment system at the Savannah River Site. The existing water treatment system utilizes air stripping as the unit operation to remove organic compounds from groundwater that also contains mercury (C ~ 250 ng/L). The baseline air stripping process was ineffective in removing mercury and the water exceeded a proposed limit of 51 ng/L. To test an enhancement to the existing treatment modality a continuous dose of reducing agent was injected for 6-hours at the inlet of the air stripper. This action resulted in the chemical reduction of mercury to Hg(0), a species that is removable with the existing unit operation. During the injection period a 94% decrease in concentration was observed and the effluent satisfied proposed limits. The process was optimized over a 2-day period by sequentially evaluating dose rates ranging from 0.64X to 297X stoichiometry. A minimum dose of 16X stoichiometry was necessary to initiate the reduction reaction that facilitated the mercury removal. Competing electron acceptors likely inhibited the reaction at the lower 1 doses, which prevented removal by air stripping. These results indicate that chemical reduction coupled with air stripping can effectively treat large-volumes of water to emerging part per trillion regulatory standards for mercury.

  15. Performance of two swine manure treatment systems on chemical composition and on the reduction of pathogens.

    Science.gov (United States)

    Viancelli, A; Kunz, A; Steinmetz, R L R; Kich, J D; Souza, C K; Canal, C W; Coldebella, A; Esteves, P A; Barardi, C R M

    2013-01-01

    Swine effluents must be correctly handled to avoid negative environmental impacts. In this study, the profiles of two swine manure treatment systems were evaluated: a solid-liquid separation step, followed by an anaerobic reactor, and an aerobic step (System 1); and a biodigester followed by serial lagoons (System 2). Both systems were described by the assessment of chemical, bacterial and viral parameters. The results showed that in System 1, there was reduction of chemicals (COD, phosphorus, total Kjeldhal nitrogen - TKN - and NH(3)), total coliforms and Escherichia coli; however, the same reduction was not observed for Salmonella sp. Viral particles were significantly reduced but not totally eliminated from the effluent. In System 2, there was a reduction of chemicals, bacteria and viruses with no detection of Salmonella sp., circovirus, parvovirus, and torque teno virus in the effluent. The chemical results indicate that the treated effluent can be reused for cleaning swine facilities. However, the microbiological results show a need of additional treatment to achieve a complete inactivation for cases when direct contact with animals is required. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Fundamental limits on gas-phase chemical reduction of NOx in a plasma

    Energy Technology Data Exchange (ETDEWEB)

    Penetrante, B.M.; Hsiao, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

    1997-12-31

    In the plasma, the electrons do not react directly with the NOx molecules. The electrons collide mainly with the background gas molecules like N{sub 2}, O{sub 2} and H{sub 2}O. Electron impact on these molecules result partly in dissociation reactions that produce reactive species like N, O and OH. The NOx in the engine exhaust gas initially consist mostly of NO. The ground state nitrogen atom, N, is the only species that could lead to the chemical reduction of NO to N{sub 2}. The O radical oxidizes NO to NO{sub 2} leaving the same amount of NOx. The OH radical converts NO{sub 2} to nitric acid. Acid products in the plasma can easily get adsorbed on surfaces in the plasma reactor and in the pipes. When undetected, the absence of these oxidation products can often be mistaken for chemical reduction of NOx. In this paper the authors will examine the gas-phase chemical reduction of NOx. They will show that under the best conditions, the plasma can chemically reduce 1.6 grams of NOx per brake-horsepower-hour [g(NOx)/bhp-hr] when 5% of the engine output energy is delivered to the plasma.

  17. Removal of PCBs in contaminated soils by means of chemical reduction and advanced oxidation processes.

    Science.gov (United States)

    Rybnikova, V; Usman, M; Hanna, K

    2016-09-01

    Although the chemical reduction and advanced oxidation processes have been widely used individually, very few studies have assessed the combined reduction/oxidation approach for soil remediation. In the present study, experiments were performed in spiked sand and historically contaminated soil by using four synthetic nanoparticles (Fe(0), Fe/Ni, Fe3O4, Fe3 - x Ni x O4). These nanoparticles were tested firstly for reductive transformation of polychlorinated biphenyls (PCBs) and then employed as catalysts to promote chemical oxidation reactions (H2O2 or persulfate). Obtained results indicated that bimetallic nanoparticles Fe/Ni showed the highest efficiency in reduction of PCB28 and PCB118 in spiked sand (97 and 79 %, respectively), whereas magnetite (Fe3O4) exhibited a high catalytic stability during the combined reduction/oxidation approach. In chemical oxidation, persulfate showed higher PCB degradation extent than hydrogen peroxide. As expected, the degradation efficiency was found to be limited in historically contaminated soil, where only Fe(0) and Fe/Ni particles exhibited reductive capability towards PCBs (13 and 18 %). In oxidation step, the highest degradation extents were obtained in presence of Fe(0) and Fe/Ni (18-19 %). The increase in particle and oxidant doses improved the efficiency of treatment, but overall degradation extents did not exceed 30 %, suggesting that only a small part of PCBs in soil was available for reaction with catalyst and/or oxidant. The use of organic solvent or cyclodextrin to improve the PCB availability in soil did not enhance degradation efficiency, underscoring the strong impact of soil matrix. Moreover, a better PCB degradation was observed in sand spiked with extractable organic matter separated from contaminated soil. In contrast to fractions with higher particle size (250-500 and oxidation reactions in soils and understand the impact of soil properties on remediation performance.

  18. Alloy composition dependence of formation of porous Ni prepared by rapid solidification and chemical dealloying

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhen [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Zhang Zhonghua [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)], E-mail: zh_zhang@sdu.edu.cn; Jia Haoling [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Qu Yingjie [Shandong Labor Occupational Technology College, Jingshi Road 388, Jinan 250022 (China); Liu Guodong; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)

    2009-03-20

    In this paper, the effect of alloy composition on the formation of porous Ni catalysts prepared by chemical dealloying of rapidly solidified Al-Ni alloys has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and N{sub 2} adsorption experiments. The experimental results show that rapid solidification and alloy composition have a significant effect on the phase constituent and microstructure of Al-Ni alloys. The melt spun Al-20 at.% Ni alloy consists of {alpha}-Al, NiAl{sub 3} and Ni{sub 2}Al{sub 3}, while the melt spun Al-25 and 31.5 at.% Ni alloys comprise NiAl{sub 3} and Ni{sub 2}Al{sub 3}. Moreover, the formation and microstructure of the porous Ni catalysts are dependent upon the composition of the melt spun Al-Ni alloys. The morphology and size of Ni particles in the Ni catalysts inherit from those of grains in the melt spun Al-Ni alloys. Rapid solidification can extend the alloy composition of Al-Ni alloys suitable for preparation of the Ni catalysts, and obviously accelerate the dealloying process of the Al-Ni alloys.

  19. Synthesis and Characterization of Graphene Thin Films by Chemical Reduction of Exfoliated and Intercalated Graphite Oxide

    Directory of Open Access Journals (Sweden)

    F. T. Thema

    2013-01-01

    Full Text Available Commercial flakes of graphite were prepared into functionalized graphene oxide (GO by chemical treatment. After the exfoliation and intercalation of graphene into functionalized graphene oxide that formed stable colloidal dispersion in polar aprotic solvent, the reduction process was undertaken by continuous stirring with hydrazine hydrate. The reduced material was characterized by X-ray diffraction (XRD, attenuated total reflectance (ATR FT-IR, ultraviolet visible (UV-vis, atomic force microscopy (AFM and Raman spectroscopy which confirm the oxidation of graphite and reduction of graphene oxide into graphene sheet.

  20. On the chemical and electrochemical one-electron reduction of peroxynitrous acid.

    Science.gov (United States)

    Kurz, Christophe; Zeng, Xiuqiong; Hannemann, Stefan; Kissner, Reinhard; Koppenol, Willem H

    2005-02-17

    Peroxynitrous acid was reduced by cathodic linear sweep voltammetry at a gold electrode and by iodide at pH 3.2 and 5.6. The cathodic reduction wave was identified by measuring its decay in time, which was the same as observed by optical spectroscopy. The iodide oxidation was followed by optical measurement of the triiodide formation. Both reductions show one-electron stoichiometry, with the product n(alpha)alpha = 0.23 +/- 0.04 from the electrochemical experiments, in which alpha is the transfer coefficient and n(alpha) the number of electrons transferred, and an diiodine yield of ca. 0.5 equiv per equivalent of peroxynitrous acid. The voltammetric reduction was irreversible up to scan rates of 80 V s(-1). Both reductions were pH independent in the range studied. The voltammetric reduction is most likely an irreversible elemental reaction followed by a chemical decay that cannot be observed directly. Because of the pH independence, we conclude that both reductions have a common short-lived intermediate, namely [HOONO]*-. We estimate the electrode potential of the likely ONOOH/ONOOH*- couple to be larger than 1 V. The commonly used electrode potential E degrees (ONOOH, H+/NO2*, H2O) does not describe the chemistry of peroxynitrous acid.

  1. Ultralow Level Mercury Treatment Using Chemical Reduction and Air Stripping: Scoping Report

    Energy Technology Data Exchange (ETDEWEB)

    Looney, B.B.

    2000-08-18

    Data collected during the first stage of a Savannah River Technology Center (SRTC) Strategic Research and Development Project confirmed the efficacy of chemical reduction and air stripping/sparging as an ultralow level mercury treatment concept for waters containing Hg(II). The process consists of dosing the water with low levels of stannous chloride to convert the mercury to Hg. This form of mercury can easily be removed from the water by air stripping or sparging. Samples of Savannah River Site (SRS) groundwater containing approximately 130 ng/L of total mercury (as Hg(II)) were used for the study. In undosed samples, sparging removed 0 percent of the initial mercury. In the dosed samples, all of the removals were greater than 94 percent, except in one water type at one dose. This sample, which was saturated with dissolved oxygen, showed a 63 percent reduction in mercury following treatment at the lowest dose. Following dosing at minimally effective levels and sparging, treated water contained less than 10 ng/L total mercury. In general, the data indicate that the reduction of mercury is highly favored and that stannous chloride reagent efficiently targets the Hg(II) contaminant in the presence of competing reactions. Based on the results, the authors estimated that the costs of implementing and operating an ultralow level mercury treatment process based on chemical reduction and stripping/sparging are 10 percent to 20 percent of traditional treatment technologies.

  2. A portable photoelectrochemical probe for rapid determination of chemical oxygen demand in wastewaters.

    Science.gov (United States)

    Zhang, Shanqing; Li, Lihong; Zhao, Huijun

    2009-10-15

    A photoelectrochemical probe for rapid determination of chemical oxygen demand (COD) is developed using a nanostructured mixed-phase TiO2 photoanode, namely PeCOD probe. A UV-LED light source and a USB mircroelectrochemical station are powered and controlled by a laptop computer, which makes the probe portable for onsite COD analyses. The photoelectrochemical measurement of COD was optimized in terms of light intensity, applied bias, and pH. Under the optimized conditions, the net steady state currents originated from the oxidation of organic compounds were found to be directly proportional to COD concentrations. A practical detection limit of 0.2 ppm COD and a linear range of 0-120 ppm COD were achieved. The analytical method using the portable PeCOD probe has the advantages of being rapid, low cost, robust, user-friendly, and environmental friendly. It has been successfully applied to determine the COD values of the synthetic samples consisting of potassium hydrogen phthalate, D-glucose, glutamic acid, glutaric acid, succinic acid, and malonic acid, and real samples from various industries, such as bakery, oil and grease manufacturer, poultry, hotel, fine food factory, and fresh food producer, commercial bread manufacturer. Excellent agreement between the proposed method and the conventional COD method (dichromate) was achieved.

  3. Learning to rapidly re-contact the lost plume in chemical plume tracing.

    Science.gov (United States)

    Cao, Meng-Li; Meng, Qing-Hao; Wang, Jia-Ying; Luo, Bing; Jing, Ya-Qi; Ma, Shu-Gen

    2015-03-27

    Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT). In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF). In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF) method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS) method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF.

  4. Learning to Rapidly Re-Contact the Lost Plume in Chemical Plume Tracing

    Directory of Open Access Journals (Sweden)

    Meng-Li Cao

    2015-03-01

    Full Text Available Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT. In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF. In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF.

  5. Learning to Rapidly Re-Contact the Lost Plume in Chemical Plume Tracing

    Science.gov (United States)

    Cao, Meng-Li; Meng, Qing-Hao; Wang, Jia-Ying; Luo, Bing; Jing, Ya-Qi; Ma, Shu-Gen

    2015-01-01

    Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT). In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF). In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF) method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS) method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF. PMID:25825974

  6. Stochastic reduction method for biological chemical kinetics using time-scale separation.

    Science.gov (United States)

    Pahlajani, Chetan D; Atzberger, Paul J; Khammash, Mustafa

    2011-03-07

    Many processes in cell biology encode and process information and enact responses by modulating the concentrations of biological molecules. Such modulations serve functions ranging from encoding and transmitting information about external stimuli to regulating internal metabolic states. To understand how such processes operate requires gaining insights into the basic mechanisms by which biochemical species interact and respond to internal and external perturbations. One approach is to model the biochemical species concentrations through the van Kampen Linear Noise Equations, which account for the change in biochemical concentrations from reactions and account for fluctuations in concentrations. For many systems, the Linear Noise Equations exhibit stiffness as a consequence of the chemical reactions occurring at significantly different rates. This presents challenges in the analysis of the kinetics and in performing efficient numerical simulations. To deal with this source of stiffness and to obtain reduced models more amenable to analysis, we present a systematic procedure for obtaining effective stochastic dynamics for the chemical species having relatively slow characteristic time scales while eliminating representations of the chemical species having relatively fast characteristic time scales. To demonstrate the applicability of this multiscale technique in the context of Linear Noise Equations, the reduction is applied to models of gene regulatory networks. Results are presented which compare numerical results for the full system to the reduced descriptions. The presented stochastic reduction procedure provides a potentially versatile tool for systematically obtaining reduced approximations of Linear Noise Equations. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. High-Quality Reduced Graphene Oxide by a Dual-Function Chemical Reduction and Healing Process

    Science.gov (United States)

    Some, Surajit; Kim, Youngmin; Yoon, Yeoheung; Yoo, HeeJoun; Lee, Saemi; Park, Younghun; Lee, Hyoyoung

    2013-01-01

    A new chemical dual-functional reducing agent, thiophene, was used to produce high-quality reduced graphene oxide (rGO) as a result of a chemical reduction of graphene oxide (GO) and the healing of rGO. Thiophene reduced GO by donation of electrons with acceptance of oxygen while it was converted into an intermediate oxidised polymerised thiophene that was eventually transformed into polyhydrocarbon by loss of sulphur atoms. Surprisingly, the polyhydrocarbon template helped to produce good-quality rGOC (chemically reduced) and high-quality rGOCT after thermal treatment. The resulting rGOCT nanosheets did not contain any nitrogen or sulphur impurities, were highly deoxygenated and showed a healing effect. Thus the electrical properties of the as-prepared rGOCT were superior to those of conventional hydrazine-produced rGO that require harsh reaction conditions. Our novel dual reduction and healing method with thiophene could potentially save energy and facilitate the commercial mass production of high-quality graphene. PMID:23722643

  8. Efficient parametric analysis of the chemical master equation through model order reduction

    Directory of Open Access Journals (Sweden)

    Waldherr Steffen

    2012-07-01

    Full Text Available Abstract Background Stochastic biochemical reaction networks are commonly modelled by the chemical master equation, and can be simulated as first order linear differential equations through a finite state projection. Due to the very high state space dimension of these equations, numerical simulations are computationally expensive. This is a particular problem for analysis tasks requiring repeated simulations for different parameter values. Such tasks are computationally expensive to the point of infeasibility with the chemical master equation. Results In this article, we apply parametric model order reduction techniques in order to construct accurate low-dimensional parametric models of the chemical master equation. These surrogate models can be used in various parametric analysis task such as identifiability analysis, parameter estimation, or sensitivity analysis. As biological examples, we consider two models for gene regulation networks, a bistable switch and a network displaying stochastic oscillations. Conclusions The results show that the parametric model reduction yields efficient models of stochastic biochemical reaction networks, and that these models can be useful for systems biology applications involving parametric analysis problems such as parameter exploration, optimization, estimation or sensitivity analysis.

  9. Evaluating the effectiveness of risk-reduction strategies for consumer chemical products.

    Science.gov (United States)

    Riley, D M; Fischhoff, B; Small, M J; Fischbeck, P

    2001-04-01

    Communication about risks offers a voluntary approach to reducing exposure to pollutants. Its adequacy depends on its impact on behavior. Estimating those impacts first requires characterizing current activities and their associated risk levels, and then predicting the effectiveness of risk-reduction strategies. Characterizing the risks from chemical consumer products requires knowledge of both the physical and the behavioral processes that influence exposures. This article presents an integrated approach that combines consumer interviews, users' beliefs and behaviors, and quantitative exposure modeling. This model was demonstrated in the context of consumer exposure to a methylene chloride-based paint stripper, showing how it could be used to evaluate current levels of risk and predict the effectiveness of proposed voluntary risk-reduction strategies.

  10. Graphite oxide platelets functionalized by poly(ionic liquid) brushes and their chemical reduction

    Energy Technology Data Exchange (ETDEWEB)

    Yang Jintao, E-mail: yangjt@zjut.edu.cn; Yan Xiaohui; Chen Feng; Fan Ping; Zhong Mingqiang [College of Chemical Engineering and Materials Science, Zhejiang University of Technology (China)

    2013-01-15

    In this paper, graphite oxide (GO) platelets functionalized by poly(ionic liquid) brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The chemical reduction of these functionalized platelets was also investigated. The functionalized platelets and their reduced products were characterized and confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, {zeta} potential measurements, four-probe electrical measurements, and high-resolution transmission electron microscopy. Results demonstrated that the poly(ionic liquid) brushes could be grafted from the GO surface by SI-ATRP. The surface charges of the GO platelets surface transformed from negative to positive. Upon reduction by hydrazine, the functionalized platelets were partially reduced, as suggested by the observation that reduced GO exhibits electrical conductivity three magnitudes higher than that of original GO. Although partially reduced GO platelets were not as conductive as reduced GO without functionalization, they can be homogenously dispersed in water due to the presence of poly(ionic liquids) brushes.

  11. Rapid Reduction in Breast Cancer Mortality With Inorganic Arsenic in Drinking Water

    Directory of Open Access Journals (Sweden)

    Allan H. Smith

    2014-11-01

    Interpretation: We found biologically plausible major reductions in breast cancer mortality during high exposure to inorganic arsenic in drinking water which could not be attributed to bias or confounding. We recommend clinical trial assessment of inorganic arsenic in the treatment of advanced breast cancer.

  12. Peripheral metabolic responses to prolonged weight reduction that promote rapid, efficient regain in obesity-prone rats.

    Science.gov (United States)

    MacLean, Paul S; Higgins, Janine A; Jackman, Matthew R; Johnson, Ginger C; Fleming-Elder, Brooke K; Wyatt, Holly R; Melanson, Edward L; Hill, James O

    2006-06-01

    Weight regain after weight loss is the most significant impediment to long-term weight reduction. We have developed a rodent paradigm that models the process of regain after weight loss, and we have employed both prospective and cross-sectional analyses to characterize the compensatory adaptations to weight reduction that may contribute to the propensity to regain lost weight. Obese rats were fed an energy-restricted (50-60% kcal) low-fat diet that reduced body weight by 14%. This reduced weight was maintained for up to 16 wk with limited provisions of the low-fat diet. Intake restriction was then removed, and the rats were followed for 56 days as they relapsed to the obese state. Prolonged weight reduction was accompanied by 1) a persistent energy gap resulting from an increased drive to eat and a reduced expenditure of energy, 2) a higher caloric efficiency of regain that may be linked with suppressed lipid utilization early in the relapse process, 3) preferential lipid accumulation in adipose tissue accompanied by adipocyte hyperplasia, and 4) humoral adiposity signals that underestimate the level of peripheral adiposity and likely influence the neural pathways controlling energy balance. Taken together, long-term weight reduction in this rodent paradigm is accompanied by a number of interrelated compensatory adjustments in the periphery that work together to promote rapid and efficient weight regain. These metabolic adjustments to weight reduction are discussed in the context of a homeostatic feedback system that controls body weight.

  13. Rapid thermal chemical vapor deposition growth of nanometer-thin SiC on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Steckl, A.J.; Li, J.P. (Univ. of Cincinnati, OH (United States))

    1992-08-28

    Rapid thermal chemical vapor deposition growth of [beta]-SiC ultrathin films on Si (100) was achieved using the carbonization reaction of the silicon substrate with C[sub 3]H[sub 8] gas. Growth rates of 0.5-2 nm s[sup -1] have been achieved at 1100-1300degC using C[sub 3]H[sub 8] flow rates of 7-9 standard cm[sup 3] min[sup -1]. X-ray and electron diffraction indicate single-crystal growth. Therefore nanometer-scale SiC films can be grown by controlling the reaction time to a few seconds. The activation energy at atmospheric pressure is 3.12 eV. The growth rate was found to decrease significantly at higher C[sub 3]H[sub 8] flow rates, leading to films of constant thickness beyond a certain critical reaction time. Using this regime of self-limiting growth, SiC films of 3-5 nm have been grown with relatively little sensitivity to the growth time. (orig.).

  14. Investigation of the reductive cleavage of BINAP and application to the rapid synthesis of phospholes.

    Science.gov (United States)

    Gallop, Chris W D; Bobin, Mariusz; Hourani, Petra; Dwyer, Jessica; Roe, S Mark; Viseux, Eddy M E

    2013-07-05

    A rapid and easy entry into λ(3)-phospholes and λ(4)-phosphole oxides derived from BINAP is reported herein featuring a variety of C and Si substituents and functional groups, as well the investigative work on the mechanistic pathway. DFT calculations using B3LYP functionals have been carried out to rationalize the mechanism. The observed experimental (31)P resonance shifts were compared with the calculated shifts of the proposed intermediates after calibration of the shielding tensors. The calculations included the use of polarizable continuum models to take into account solvent effects and were found to be in excellent agreement, providing further evidence for the proposed mechanism.

  15. The effect of rapid diagnostic testing for influenza on the reduction of antibiotic use in paediatric emergency department.

    Science.gov (United States)

    Ozkaya, E; Cambaz, N; Coşkun, Y; Mete, F; Geyik, M; Samanci, N

    2009-10-01

    To determine the influence of rapid diagnosis of influenza on antibiotic prescribing to children presenting with influenza-like illness in the emergency department in a inner city hospital in Istanbul, Turkey. Patients aged 3 to 14 years presenting to an urban children's teaching hospital emergency department were screened for fever and cough, coryza, myalgias and/or malaise. After obtaining informed consent, patients were allocated into two groups. Group 1: patients were prescribed antibiotics after only physical examination; or Group 2: patients were prescribed antibiotics after rapid influenza testing. Nasopharyngeal swabs obtained from all patients were immediately tested in a single-blind manner with Influenza A/B Rapid Test(R) for influenza A and B. A total of 97 patients were enrolled, and 33 (34%) of these tested positive for influenza. Although frequency of positive results for influenza between the groups was similar (36% vs 32%, respectively), patients in Group 2 were less likely to be prescribed antibiotics when compared to those in Group 1 (32% vs 100%, respectively, p < 0.0001). Rapid diagnosis of influenza in the paediatric emergency department may allow a significant reduction in the over-prescription of antibiotics.

  16. Moisture-induced solid state instabilities in α-chymotrypsin and their reduction through chemical glycosylation

    Directory of Open Access Journals (Sweden)

    Solá Ricardo J

    2010-08-01

    Full Text Available Abstract Background Protein instability remains the main factor limiting the development of protein therapeutics. The fragile nature (structurally and chemically of proteins makes them susceptible to detrimental events during processing, storage, and delivery. To overcome this, proteins are often formulated in the solid-state which combines superior stability properties with reduced operational costs. Nevertheless, solid protein pharmaceuticals can also suffer from instability problems due to moisture sorption. Chemical protein glycosylation has evolved into an important tool to overcome several instability issues associated with proteins. Herein, we employed chemical glycosylation to stabilize a solid-state protein formulation against moisture-induced deterioration in the lyophilized state. Results First, we investigated the consequences of moisture sorption on the stability and structural conformation of the model enzyme α-chymotrypsin (α-CT under controlled humidity conditions. Results showed that α-CT aggregates and inactivates as a function of increased relative humidity (RH. Furthermore, α-CT loses its native secondary and tertiary structure rapidly at increasing RH. In addition, H/D exchange studies revealed that α-CT structural dynamics increased at increasing RH. The magnitude of the structural changes in tendency parallels the solid-state instability data (i.e., formation of buffer-insoluble aggregates, inactivation, and loss of native conformation upon reconstitution. To determine if these moisture-induced instability issues could be ameliorated by chemical glycosylation we proceeded to modify our model protein with chemically activated glycans of differing lengths (lactose and dextran (10 kDa. The various glycoconjugates showed a marked decrease in aggregation and an increase in residual activity after incubation. These stabilization effects were found to be independent of the glycan size. Conclusion Water sorption leads to

  17. A novel green synthesis and characterization of Ag NPs with its ultra-rapid catalytic reduction of methyl green dye

    Energy Technology Data Exchange (ETDEWEB)

    Junejo, Y., E-mail: yasmeengul14@yahoo.com [National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Jamshoro 76080 (Pakistan); Department of Chemistry, Fatih University, Buyukcekmece, 34500 Istanbul (Turkey); Sirajuddin [National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Jamshoro 76080 (Pakistan); Baykal, A. [Department of Chemistry, Fatih University, Buyukcekmece, 34500 Istanbul (Turkey); Safdar, M. [Department of Genetics and Bioengineering, Faculty of Engineering, Fatih University, 34500, Büyükçekmece, İstanbul (Turkey); Balouch, A. [National Centre of Excellence in Analytical Chemistry, University of Sindh Jamshoro, Jamshoro 76080 (Pakistan)

    2014-01-30

    Ampicillin derived silver nanoparticles were synthesized in an aqueous medium. Particle size and shape were determined by Transmission electron microscopy which showed the monodispersed morphology. The Fourier transform infrared spectra were represented the interaction of Ampicillin with surface of Ampicillin derived silver nanoparticles. X-ray powder diffraction study gave crystalline nature of the Ampicillin derived silver nanoparticles which exhibited exceptional catalytic activity for the reduction of Methylene Green dye. However, complete reduction of dye was accomplished by Ampicillin derived silver nanoparticles within 4 min only. The catalytic performance of these nanoparticles was adsorbed on glass. They were recovered easily from reaction medium and reused with enhanced catalytic potential. Based upon these results it has been concluded that Ampicillin derived silver nanoparticles are novel, rapid and highly economical alternative for environmental safety against pollution by dyes and extendable for control of other reducible contaminants as well.

  18. Visible light Cr(VI) reduction and organic chemical oxidation by TiO2 photocatalysis.

    Science.gov (United States)

    Sun, Bo; Reddy, Ettireddy P; Smirniotis, Panagiotis G

    2005-08-15

    Here we report the simultaneous Cr(VI) reduction and 4-chlorophenol (4-CP) oxidation in water under visible light (wavelength > 400 nm) using commercial Degussa P25 TiO2. This remarkable observation was attributed to a synergistic effect among TiO2, Cr(VI), and 4-CP. It is well known that TiO2 alone cannot remove either 4-CP or Cr(VI) efficiently under visible light. Moreover, the interaction between Cr(VI) and 4-CP is minimal if not negligible. However, we found that the combination of TiO2, Cr(VI), and 4-CP together can enable efficient Cr(VI) reduction and 4-CP oxidation under visible light. The specific roles of the three ingredients in the synergistic system were studied parametrically. It was found that optimal concentrations of Cr(VI) and TiO2 exist for the Cr(VI) reduction and 4-CP oxidation. Cr(VI) was compared experimentally with other metals such as Cu(ll), Fe(lll), Mn(IV), Ce(IV), and V(V). Among all these metal ions, only Cr(VI) promotes the photocatalytic oxidation of 4-CP. The amount of 4-CP removed was directly related to the initial concentration of Cr(VI). The system was also tested with four other chemicals (aniline, salicylic acid, formic acid, and diethyl phosphoramidate). We found that the same phenomenon occurred for organics containing acid and/or phenolic groups. Cr(VI) was reduced at the same time as the organic chemicals being oxidized during photoreaction under visible light. The synergistic effect was also found with pure anatase TiO2 and rutile TiO2. This study demonstrates a possible economical way for environmental cleanup under visible light.

  19. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2018-03-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  20. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2017-12-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  1. Reduction kinetics of iron-based oxygen carriers using methane for chemical-looping combustion

    Science.gov (United States)

    Luo, Ming; Wang, Shuzhong; Wang, Longfei; Lv, Mingming

    2014-12-01

    The performance of three iron-based oxygen carriers (pure Fe2O3, synthetic Fe2O3/MgAl2O4 and iron ore) in reduction process using methane as fuel is investigated in thermo-gravimetric analyzer (TGA). The reaction rate and mechanism between three oxygen carriers and methane are investigated. On the basis of reactivity in reduction process, it may be concluded that Fe2O3/MgAl2O4 has the best reactivity with methane. The reaction rate constant is found to be in the following order: Fe2O3/MgAl2O4 > pure Fe2O3 > iron ore and the activation energy varies between 49 and 184 kJ mol-1. Reduction reactions for the pure Fe2O3 and synthetic Fe2O3/MgAl2O4 are well represented by the reaction controlling mechanism, and for the iron ore the phase-boundary controlled (contracting cylinder) model dominates. The particles of iron ore and synthetic Fe2O3/MgAl2O4 have better stability than that of pure Fe2O3 when the reaction temperature is limited to lower than 1223 K. These preliminary results suggest that iron-based mixed oxygen carrier particles are potential to be used in methane chemical looping process, but the reactivity of the iron ore needs to be increased.

  2. Rapid reduction versus abrupt quitting for smokers who want to stop soon: a randomised controlled non-inferiority trial

    Directory of Open Access Journals (Sweden)

    West Robert

    2009-08-01

    Full Text Available Abstract Background The standard way to stop smoking is to stop abruptly on a quit day with no prior reduction in consumption of cigarettes. Many smokers feel that reduction is natural and if reduction programmes were offered, many more might take up treatment. Few trials of reduction versus abrupt cessation have been completed. Most are small, do not use pharmacotherapy, and do not meet the standards necessary to obtain a marketing authorisation for a pharmacotherapy. Design/Methods We will conduct a non-inferiority randomised trial of rapid reduction versus standard abrupt cessation among smokers who want to stop smoking. In the reduction arm, participants will be advised to reduce smoking consumption by half in the first week and to 25% of baseline in the second, leading up to a quit day at which participants will stop smoking completely. This will be assisted by nicotine patches and an acute form of nicotine replacement therapy. In the abrupt arm participants will use nicotine patches only, whilst smoking as normal, for two weeks prior to a quit day, at which they will also stop smoking completely. Smokers in either arm will have standard withdrawal orientated behavioural support programme with a combination of nicotine patches and acute nicotine replacement therapy post-cessation. Outcomes/Follow-up The primary outcome of interest will be prolonged abstinence from smoking, with secondary trial outcomes of point prevalence, urges to smoke and withdrawal symptoms. Follow up will take place at 4 weeks, 8 weeks and 6 months post-quit day. Trial Registration Current Controlled Trials ISRCTN22526020

  3. Gold Decorated Graphene for Rapid Dye Reduction and Efficient Electro Catalytic Oxidation of Ethanol

    Science.gov (United States)

    Siddhardha, R. S.; Kumar v, Lakshman; Kaniyoor, A.; Podila, R.; Kumar, V. S.; Venkataramaniah, K.; Ramaprabhu, S.; Rao, A.; Ramamurthy, S. S.; Clemson University Team; Sri Sathya Sai Institute of Higher Learning Team; IITMadras Team

    2013-03-01

    A well known disadvantage in fabrication of metal-graphene composite is the use of surfactants that strongly adsorb on the surface and reduce the performance of the catalyst. Here, we demonstrate a novel one pot synthesis of gold nanoparticles (AuNPs) by laser ablation of gold strip and simultaneous decoration of these on functionalized graphene derivatives. Not only the impregnation of AuNPs was linker free, but also the synthesis by itself was surfactant free. This resulted in in-situ decoration of pristine AuNPs on functionalized graphene derivatives. These materials were well characterized and tested for catalytic applications pertaining to dye reduction and electrooxidation. The catalytic reduction rates are 1.4 x 102 and 9.4x102 times faster for Rhodamine B and Methylene Blue dyes respectively, compared to earlier reports. The enhanced rate involves synergistic interplay of electronic relay between AuNPs and the dye, also charge transfer between the graphene system and dye. In addition, the onset potential for ethanol oxidation was found to be more negative ~ 100 mV, an indication of its promising application in direct ethanol fuel cells.

  4. Enhanced Activity of Supported Ni Catalysts Promoted by Pt for Rapid Reduction of Aromatic Nitro Compounds

    Directory of Open Access Journals (Sweden)

    Huishan Shang

    2016-06-01

    Full Text Available To improve the activities of non-noble metal catalysts is highly desirable and valuable to the reduced use of noble metal resources. In this work, the supported nickel (Ni and nickel-platinum (NiPt nanocatalysts were derived from a layered double hydroxide/carbon composite precursor. The catalysts were characterized and the role of Pt was analysed using X-ray diffraction (XRD, high-resolution transmission electron microscopy (HRTEM, energy dispersive X-ray spectroscopy (EDS mapping, and X-ray photoelectron spectroscopy (XPS techniques. The Ni2+ was reduced to metallic Ni0 via a self-reduction way utilizing the carbon as a reducing agent. The average sizes of the Ni particles in the NiPt catalysts were smaller than that in the supported Ni catalyst. The electronic structure of Ni was affected by the incorporation of Pt. The optimal NiPt catalysts exhibited remarkably improved activity toward the reduction of nitrophenol, which has an apparent rate constant (Ka of 18.82 × 10−3 s−1, 6.2 times larger than that of Ni catalyst and also larger than most of the reported values of noble-metal and bimetallic catalysts. The enhanced activity could be ascribed to the modification to the electronic structure of Ni by Pt and the effect of exposed crystal planes.

  5. One-pot wet-chemical co-reduction synthesis of bimetallic gold-platinum nanochains supported on reduced graphene oxide with enhanced electrocatalytic activity

    Science.gov (United States)

    Chen, De-Jun; Zhang, Qian-Li; Feng, Jin-Xia; Ju, Ke-Jian; Wang, Ai-Jun; Wei, Jie; Feng, Jiu-Ju

    2015-08-01

    In this work, a simple, rapid and facile one-pot wet-chemical co-reduction method is developed for synthesis of bimetallic Au-Pt alloyed nanochains supported on reduced graphene oxide (Au-Pt NCs/RGO), in which caffeine is acted as a capping agent and a structure-directing agent, while no any seed, template, surfactant or polymer involved. The as-prepared nanocomposites display enlarged electrochemical active surface area, significantly enhanced catalytic activity and better stability for methanol and ethylene glycol oxidation, compared with commercial Pt-C (Pt 50 wt%), PtRu-C (Pt 30 wt% and Ru 15 wt%) and Pt black.

  6. Ni removal from aqueous solutions by chemical reduction: Impact of pH and pe in the presence of citrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chi-Wang, E-mail: chiwang@mail.tku.edu.tw [Department of Water Resources and Environmental Engineering, Tamkang University, No. 151 Yingzhuan Road, Tamsui District, New Taipei City, 25137, Taiwan (China); Yu, Jui-Hsuan [Department of Water Resources and Environmental Engineering, Tamkang University, No. 151 Yingzhuan Road, Tamsui District, New Taipei City, 25137, Taiwan (China); Department of Marine Leisure and Tourism, Taipei College of Maritime Technology, No. 150, Sec. 3, Binhai Road, Tamsui District, New Taipei City, 251, Taiwan (China); Liang, Yang-Min; Chou, Yi-Hsuan [Department of Water Resources and Environmental Engineering, Tamkang University, No. 151 Yingzhuan Road, Tamsui District, New Taipei City, 25137, Taiwan (China); Park, Hyung-June [Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566 (Korea, Republic of); Choo, Kwang-Ho, E-mail: chookh@knu.ac.kr [Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566 (Korea, Republic of); Chen, Shiao-Shing [Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Road, Taipei, 106, Taiwan (China)

    2016-12-15

    The chemical precipitation of Ni ions from industrial wastewater at alkaline pH values creates waste chemical sludge (e.g., Ni(OH){sub 2}). We herein focused on Ni removal via chemical reduction using dithionite, by converting Ni(II) to its elemental or other valuable forms. Without the presence of a chelator (e.g., citrate), the nickel reduction efficiency increased with increasing dithionite:Ni molar ratio, reaching 99% at ratios above 3:1. The effect of pH on Ni reduction was in agreement with the standard redox potentials (pe{sup 0}) of dithionite, which became more negative with an increase in pH leading to greater Ni reduction efficiencies. With the formation of Ni-citrate chelates, however, the Ni reduction deteriorated. Elevated pH and temperature improved nickel reduction, due to the greater reducing power of dithionite. The optimal pH value for Ni(II) reduction was found to be 8. Injecting Cu seed particles enhanced the rate and amount of Ni reduced. NiS and Ni{sub 3}S{sub 2} were identified in the crystal of the resulting solids by X-ray crystallography, and the presence of elemental Ni was explained by X-ray photoelectron spectroscopy. The chemical reduction of actual printed circuit board wastewater with the dithionite:Ni(II) molar ratio dose of 12:1 retrieved 99% nickel after 30-min reaction at 40 °C.

  7. Materials characterization of rapid thermal chemical vapor deposition of titanium disilicide

    Science.gov (United States)

    Gladden-Green, Dannellia Banay

    Technological advancements of novel processes and materials involving refractory metal silicides for ultra large scale integration is of paramount importance to the semiconductor industry. Scaling of devices to meet the demands for increased packing density and speed requires such novel processes and materials. Rapid thermal chemical vapor deposition (RTCVD) of titanium disilicide (TiSisb2) was investigated in an effort to meet some of the challenges of ultra large scale integration (ULSI) technology. Selective RTCVD of TiSisb2 offers an optimal technological vehicle for achieving contacts to ultra-shallow junctions. Of all of the metal silicides, TiSisb2 has the lowest resistivity and meets the microelectronics demands for a thermally stable contact. The research results presented in this dissertation explores the mechanisms of selective RTCVD of TiSisb2 in terms of thermodynamic trends and kinetic driving forces for nucleation and growth. The present research addresses the qualitative and quantitative parameters that affect the controlling mechanisms for nucleation and therefore the results provide significant data and theoretical insights into a state-of-the-art process. Just as the fundamental building block in understanding the kinetic constraints of a process lie in the realm of thermodynamic exploration, understanding the complex processes involved in RTCVD TiSisb2 begin with characterization of the mechanisms governing thin film nucleation. In this work, the early stages of growth are investigated as they offer insight into how process parameters are optimized to render desired silicide film properties. Equilibrium simulations have been used to model the CVD reaction with very good trend indicating accuracy. Empirical investigations of CVD TiSisb2 took place in a low-pressure rapid-thermal environment using the SiHsb4 + TiClsb4 gas system on silicon (100) substrates. Secondary ion mass spectroscopy (SIMS) has been used to qualify the benefits of vacuum and

  8. Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide.

    Directory of Open Access Journals (Sweden)

    Giuseppe Sorrentino

    Full Text Available The rate of photosynthesis (A of plants exposed to water deficit is a function of stomatal (gs and mesophyll (gm conductance determining the availability of CO2 at the site of carboxylation within the chloroplast. Mesophyll conductance often represents the greatest impediment to photosynthetic uptake of CO2, and a crucial determinant of the photosynthetic effects of drought. Abscisic acid (ABA plays a fundamental role in signalling and co-ordination of plant responses to drought; however, the effect of ABA on gm is not well-defined. Rose, cherry, olive and poplar were exposed to exogenous ABA and their leaf gas exchange parameters recorded over a four hour period. Application with ABA induced reductions in values of A, gs and gm in all four species. Reduced gm occurred within one hour of ABA treatment in three of the four analysed species; indicating that the effect of ABA on gm occurs on a shorter timescale than previously considered. These declines in gm values associated with ABA were not the result of physical changes in leaf properties due to altered turgor affecting movement of CO2, or caused by a reduction in the sub-stomatal concentration of CO2 (Ci. Increased [ABA] likely induces biochemical changes in the properties of the interface between the sub-stomatal air-space and mesophyll layer through the actions of cooporins to regulate the transport of CO2. The results of this study provide further evidence that gm is highly responsive to fluctuations in the external environment, and stress signals such as ABA induce co-ordinated modifications of both gs and gm in the regulation of photosynthesis.

  9. Distinguishing solid bitumens formed by thermochemical sulfate reduction and thermal chemical alteration

    Science.gov (United States)

    Kelemen, S.R.; Walters, C.C.; Kwiatek, P.J.; Afeworki, M.; Sansone, M.; Freund, H.; Pottorf, R.J.; Machel, H.G.; Zhang, T.; Ellis, G.S.; Tang, Y.; Peters, K.E.

    2008-01-01

    Insoluble solid bitumens are organic residues that can form by the thermal chemical alteration (TCA) or thermochemical sulfate reduction (TSR) of migrated petroleum. TCA may actually encompass several low temperature processes, such as biodegradation and asphaltene precipitation, followed by thermal alteration. TSR is an abiotic redox reaction where petroleum is oxidized by sulfate. It is difficult to distinguish solid bitumens associated with TCA of petroleum from those associated with TSR when both processes occur at relatively high temperature. The focus of the present work was to characterize solid bitumen samples associated with TCA or TSR using X-ray photoelectron spectroscopy (XPS). XPS is a surface analysis conducted on either isolated or in situ (>25 ??m diameter) solid bitumen that can provide the relative abundance and chemical speciation of carbon, organic and inorganic heteroatoms (NSO). In this study, naturally occurring solid bitumens from three locations, Nisku Fm. Brazeau River area (TSR-related), LaBarge Field Madison Fm. (TSR-related), and the Alaskan Brooks range (TCA-related), are compared to organic solids generated during laboratory simulation of the TSR and TCA processes. The abundance and chemical nature of organic nitrogen and sulfur in solid bitumens can be understood in terms of the nature of (1) petroleum precursor molecules, (2) the concentration of nitrogen by way of thermal stress and (3) the mode of sulfur incorporation. TCA solid bitumens originate from polar materials that are initially rich in sulfur and nitrogen. Aromaticity and nitrogen increase as thermal stress cleaves aliphatic moieties and condensation reactions take place. Organic sulfur in TCA organic solids remains fairly constant with increasing maturation (3.5 to ???17 sulfur per 100 carbons) into aromatic structures and to the low levels of nitrogen in their hydrocarbon precursors. Hence, XPS results provide organic chemical composition information that helps to

  10. A rapid technique for determination of nitrate and nitric acid by acid reduction and diazotization at elevated temperature.

    Science.gov (United States)

    Mir, S A

    2008-07-14

    A rapid technique for determination of nitrate by acid reduction and diazotization at elevated temperature has been standardized. The technique is based on quantitative diazotization of sulfanilamide by nitrate on incubation in boiling water bath for 3, 5 or 10 min in presence of high concentration of HCl, ca. 64.5%. The diazotized sulfanilamide is coupled at room temperature to N-1-(naphthyl)-ethylenediamine dihydrochloride, and the chromophore evaluated spectrophotometrically at 540 nm. The technique provides linear estimate of nitrate over the test range of 0.5 through 10 microg N mL(-1) sample with all test incubation time periods using alkali nitrate and nitric acid as sources of nitrate anion. Urea treatment enables selective determination of nitrate in presence of nitrite with overall 99+/-1% recovery, and without affecting nitrate determination (P>0.1) or its regression coefficient. The technique has obvious advantages over metal-reduction technique. It is simple, rapid, selective in presence of nitrite, and an inexpensive method for routine determination of nitrate with detection range 0.5-10 microg N mL(-1) sample. Besides, the technique provides opportunity to detect nitric acid as low as 35 microM even in presence of other acids.

  11. Microwave-assisted chemical insertion: a rapid technique for screening cathodes for Mg-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kaveevivitchai, Watchareeya; Huq, Ashfia; Manthiram, Arumugam

    2016-12-19

    We report an ultrafast microwave-assisted solvothermal method for chemical insertion of Mg2+ ions into host materials using magnesium acetate [Mg(CH3COO)2] as a metal-ion source and diethylene glycol (DEG) as a reducing agent. For instance, up to 3 Mg ions per formula unit of a microporous host framework Mo2.5+yVO9+z could be inserted in as little as 30 min at 170–195 °C in air. This process is superior to the traditional method which involves the use of organometallic reagents, such as di-n-butylmagnesium [(C4H9)2Mg] and magnesium bis(2,6-di-tert-butylphenoxide) [Mg-(O-2,6-But2C6H3)2], and requires an inert atmosphere with extremely long reaction times. Considering the lack of robust electrolytes for Mg-ion batteries, this facile approach can be readily used as a rapid screening technique to identify potential Mg-ion electrode hosts without the necessity of fabricating electrodes and assembling electrochemical cells. Due to the mild reaction conditions, the overall structure and morphology of the Mg-ion inserted products are maintained and the compounds can be used successfully as a cathode in Mg-ion batteries. The combined synchrotron X-ray and neutron diffraction Rietveld analysis reveals the structure of the Mg-inserted compounds and gives an insight into the interactions between the Mg ions and the open-tunnel host framework.

  12. Understanding the Rapid Reduction of Undernutrition in Nepal, 2001-2011.

    Directory of Open Access Journals (Sweden)

    Derek D Headey

    Full Text Available South Asia has long been synonymous with unusually high rates of undernutrition. In the past decade, however, Nepal has arguably achieved the fastest recorded decline in child stunting in the world and has done so in the midst of civil war and post-conflict political instability. Given recent interest in reducing undernutrition-particularly the role of nutrition-sensitive policies-this paper aims to quantitatively understand this surprising success story by analyzing the 2001, 2006, and 2011 rounds of Nepal's Demographic Health Surveys. To do so, we construct models of the intermediate determinants of child and maternal nutritional change and then decompose predicted changes in nutrition outcomes over time. We identify four broad drivers of change: asset accumulation, health and nutrition interventions, maternal educational gains, and improvements in sanitation. Many of these changes were clearly influenced by policy decisions, including increased public investments in health and education and community-led health and sanitation campaigns. Other factors, such as rapid growth in migration-based remittances, are more a reflection of household responses to changing political and economic circumstances.

  13. Understanding the Rapid Reduction of Undernutrition in Nepal, 2001-2011.

    Science.gov (United States)

    Headey, Derek D; Hoddinott, John

    2015-01-01

    South Asia has long been synonymous with unusually high rates of undernutrition. In the past decade, however, Nepal has arguably achieved the fastest recorded decline in child stunting in the world and has done so in the midst of civil war and post-conflict political instability. Given recent interest in reducing undernutrition-particularly the role of nutrition-sensitive policies-this paper aims to quantitatively understand this surprising success story by analyzing the 2001, 2006, and 2011 rounds of Nepal's Demographic Health Surveys. To do so, we construct models of the intermediate determinants of child and maternal nutritional change and then decompose predicted changes in nutrition outcomes over time. We identify four broad drivers of change: asset accumulation, health and nutrition interventions, maternal educational gains, and improvements in sanitation. Many of these changes were clearly influenced by policy decisions, including increased public investments in health and education and community-led health and sanitation campaigns. Other factors, such as rapid growth in migration-based remittances, are more a reflection of household responses to changing political and economic circumstances.

  14. Chemical Fouling Reduction of a Submersible Steel Spectrophotometer in Estuarine Environments Using a Sacrificial Zinc Anode.

    Science.gov (United States)

    Tait, Zachary S; Thompson, Megan; Stubbins, Aron

    2015-07-01

    The availability of in situ spectrophotometers, such as the S::CAN spectro::lyser, has expanded the possibilities for high-frequency water quality data collection. However, biological and chemical fouling can degrade the performance of in situ spectrophotometers, especially in saline environments with rapid flow rates. A complex freshwater washing system has been previously designed to reduce chemical fouling for the S::CAN spectro::lyser spectrophotometer. In the current study, we present a simpler, cheaper alternative: the attachment of a sacrificial zinc anode. Results are presented detailing the S::CAN spectro::lyser performance with and without the addition of the sacrificial anode. Attachment of the zinc anode provided efficient corrosion protection during 2-wk deployments in a highly dynamic (average tidal range, 2.5 m) saline tidal saltmarsh creek at Groves Creek, Skidaway Institute of Oceanography, Savannah, GA. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  15. Rapid reduction in breast cancer mortality with inorganic arsenic in drinking water.

    Science.gov (United States)

    Smith, Allan H; Marshall, Guillermo; Yuan, Yan; Steinmaus, Craig; Liaw, Jane; Smith, Martyn T; Wood, Lily; Heirich, Marissa; Fritzemeier, Rebecca M; Pegram, Mark D; Ferreccio, Catterina

    2014-11-01

    Arsenic trioxide is effective in treating promyelocytic leukemia, and laboratory studies demonstrate that arsenic trioxide causes apoptosis of human breast cancer cells. Region II in northern Chile experienced very high concentrations of inorganic arsenic in drinking water, especially in the main city Antofagasta from 1958 until an arsenic removal plant was installed in 1970. We investigated breast cancer mortality from 1950 to 2010 among women in Region II compared to Region V, which had low arsenic water concentrations. We conducted studies on human breast cancer cell lines and compared arsenic exposure in Antofagasta with concentrations inducing apoptosis in laboratory studies. Before 1958, breast cancer mortality rates were similar, but in 1958-1970 the rates in Region II were half those in Region V (rate ratio RR = 0·51, 95% CI 0·40-0·66; parsenic concentrations close to those estimated to have occurred in people in Region II. We found biologically plausible major reductions in breast cancer mortality during high exposure to inorganic arsenic in drinking water which could not be attributed to bias or confounding. We recommend clinical trial assessment of inorganic arsenic in the treatment of advanced breast cancer.

  16. Reduction of uranyl carbonate and hydroxyl complexes and neptunyl carbonate complexes studied with chemical-electrochemical methods and rixs spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Butorin, Sergei; Nordgren, Joseph [Uppsala Univ. (Sweden); Ollila, Kaija [VTT Processes, Jyvaeskylae (Finland); Albinsson, Yngve [Chalmers Univ. of Technology, Goeteborg (Sweden); Werme, Lars [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2003-10-01

    . Once these actinides have been mobilised through oxidation, they can migrate away from this potentially oxidising region and will encounter an oxygen free, reducing environment caused by the anaerobic corrosion of the cast iron insert. The actinyl species are no longer thermodynamically stable and reduction to the tetravalent state will be possible. There is, however, an open question whether the reduction kinetics will be sufficiently high to cause reduction in solution and if sorption onto the corroding iron surface will be accompanied by an electron transfer sufficiently rapid to reduce the actinide back to the tetravalent state. This report contains the results of experimental studies of uranium reduction-depletion from water solutions in the presence of corroding iron and spectroscopic studies of the oxidation state of uranium and neptunium sorbed/precipitated onto iron under oxygen free conditions using resonant inelastic soft x-ray scattering (RIXS) spectroscopy. The RIXS measurements show that at least partial reduction of both uranyl carbonate complexes and neptunyl carbonate complexes take place on the corroding iron surface. The chemical/electrochemical measurements indicate that reduction of uranyl carbonate complexes also take place in solution in a system containing corroding iron, i.e. sorption onto the iron/iron oxide surface may not be necessary in order for reduction to take place. Reduction of uranyl hydroxyl complexes was also found to take place in solution, but at a rate that was noticeably lower than for the uranyl carbonate complexes.

  17. Reduction and Uncertainty Analysis of Chemical Mechanisms Based on Local and Global Sensitivities

    Science.gov (United States)

    Esposito, Gaetano

    Numerical simulations of critical reacting flow phenomena in hypersonic propulsion devices require accurate representation of finite-rate chemical kinetics. The chemical kinetic models available for hydrocarbon fuel combustion are rather large, involving hundreds of species and thousands of reactions. As a consequence, they cannot be used in multi-dimensional computational fluid dynamic calculations in the foreseeable future due to the prohibitive computational cost. In addition to the computational difficulties, it is also known that some fundamental chemical kinetic parameters of detailed models have significant level of uncertainty due to limited experimental data available and to poor understanding of interactions among kinetic parameters. In the present investigation, local and global sensitivity analysis techniques are employed to develop a systematic approach of reducing and analyzing detailed chemical kinetic models. Unlike previous studies in which skeletal model reduction was based on the separate analysis of simple cases, in this work a novel strategy based on Principal Component Analysis of local sensitivity values is presented. This new approach is capable of simultaneously taking into account all the relevant canonical combustion configurations over different composition, temperature and pressure conditions. Moreover, the procedure developed in this work represents the first documented inclusion of non-premixed extinction phenomena, which is of great relevance in hypersonic combustors, in an automated reduction algorithm. The application of the skeletal reduction to a detailed kinetic model consisting of 111 species in 784 reactions is demonstrated. The resulting reduced skeletal model of 37--38 species showed that the global ignition/propagation/extinction phenomena of ethylene-air mixtures can be predicted within an accuracy of 2% of the full detailed model. The problems of both understanding non-linear interactions between kinetic parameters and

  18. Broad target chemical screening approach used as tool for rapid assessment of groundwater quality

    NARCIS (Netherlands)

    ter Laak, T.L.; Puijker, L.M.; van Leerdam, J.A.; Raat, K.J.; Kolkman, A.; de Voogt, P.; van Wezel, A.P.

    2012-01-01

    The chemical water quality is often assessed by screening for a limited set of target chemicals. This ‘conventional’ target analysis approach inevitably misses chemicals present in the samples. In this study a ‘broad’ target screening approach for water quality assessment using high resolution and

  19. The Effect of Thickness and Chemical Reduction of Graphene Oxide on Nanoscale Friction.

    Science.gov (United States)

    Kwon, Sangku; Lee, Kyung Eun; Lee, Hyunsoo; Koh, Sang Joon; Ko, Jae-Hyeon; Kim, Yong-Hyun; Kim, Sang Ouk; Park, Jeong Young

    2018-01-18

    The tribological properties of two-dimensional (2D) atomic layers are quite different from three-dimensional continuum materials because of the unique mechanical responses of 2D layers. It is known that friction on graphene shows a remarkable decreasing behavior as the number of layers increases, which is caused by the puckering effect. On other graphene derivatives, such as graphene oxide (GO) or reduced graphene oxide (rGO), the thickness dependence of friction is important because of the possibilities for technical applications. In this report, we demonstrate unexpected layer-dependent friction behavior on GO and rGO layers. Friction force microscopy measurements show that nanoscale friction on GO does not depend on the number of layers; however, after reduction, friction on rGO shows an inverse thickness dependence compared with pristine graphene. We show that the friction on rGO is higher than that on SiO2 at low load, and that an interesting crossover behavior at higher load occurs because of the lower friction coefficient and higher adhesion of the rGO. We provide a relevant interpretation that explains the effect of thickness and chemical reduction on nanoscale friction.

  20. Synthesis of Copper Nanoparticles in Ethylene Glycol by Chemical Reduction with Vanadium (+2 Salts

    Directory of Open Access Journals (Sweden)

    Andrea Pietro Reverberi

    2016-09-01

    Full Text Available Copper nanoparticles have been synthesized in ethylene glycol (EG using copper sulphate as a precursor and vanadium sulfate as an atypical reductant being active at room temperature. We have described a technique for a relatively simple preparation of such a reagent, which has been electrolytically produced without using standard procedures requiring an inert atmosphere and a mercury cathode. Several stabilizing agents have been tested and cationic capping agents have been discarded owing to the formation of complex compounds with copper ions leading to insoluble phases contaminating the metallic nanoparticles. The elemental copper nanoparticles, stabilized with polyvinylpyrrolidone (PVP and sodium dodecyl sulphate (SDS, have been characterized for composition by energy dispersive X-ray spectroscopy (EDS, and for size by dynamic light scattering (DLS, and transmission electron microscopy (TEM, giving a size distribution in the range of 40–50 nm for both stabilizing agents. From a methodological point of view, the process described here may represent an alternative to other wet-chemical techniques for metal nanoparticle synthesis in non-aqueous media based on conventional organic or inorganic reductants.

  1. In situ self-assembly of mild chemical reduction graphene for three-dimensional architectures.

    Science.gov (United States)

    Chen, Wufeng; Yan, Lifeng

    2011-08-01

    Three-dimensional (3D) architectures of graphene are of interest in applications in electronics, catalysis devices, and sensors. However, it is still a challenge to fabricate macroscopic all-graphene 3D architectures under mild conditions. Here, a simple method for the preparation of 3D architectures of graphene is developed via the in situ self-assembly of graphene prepared by mild chemical reduction at 95 °C under atmospheric pressure without stirring. No chemical or physical cross-linkers or high pressures are required. The reducing agents include NaHSO(3), Na(2)S, Vitamin C, HI, and hydroquinone. Both graphene hydrogels and aerogels can be prepared by this method, and the shapes of the 3D architectures can be controlled by changing the type of reactor. The 3D architectures of graphene have low densities, high mechanical properties, thermal stability, high electrical conductivity, and high specific capacitance, which make them candidates for potential applications in supercapacitors, hydrogen storage and as supports for catalysts. This journal is © The Royal Society of Chemistry 2011

  2. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

  3. Rapid Reduction of the Diferric-Peroxyhemiacetal Intermediate in Aldehyde-Deformylating Oxygenase by a Cyanobacterial Ferredoxin: Evidence for a Free-Radical Mechanism.

    Science.gov (United States)

    Rajakovich, Lauren J; Nørgaard, Hanne; Warui, Douglas M; Chang, Wei-chen; Li, Ning; Booker, Squire J; Krebs, Carsten; Bollinger, J Martin; Pandelia, Maria-Eirini

    2015-09-16

    Aldehyde-deformylating oxygenase (ADO) is a ferritin-like nonheme-diiron enzyme that catalyzes the last step in a pathway through which fatty acids are converted into hydrocarbons in cyanobacteria. ADO catalyzes conversion of a fatty aldehyde to the corresponding alk(a/e)ne and formate, consuming four electrons and one molecule of O2 per turnover and incorporating one atom from O2 into the formate coproduct. The source of the reducing equivalents in vivo has not been definitively established, but a cyanobacterial [2Fe-2S] ferredoxin (PetF), reduced by ferredoxin-NADP(+) reductase (FNR) using NADPH, has been implicated. We show that both the diferric form of Nostoc punctiforme ADO and its (putative) diferric-peroxyhemiacetal intermediate are reduced much more rapidly by Synechocystis sp. PCC6803 PetF than by the previously employed chemical reductant, 1-methoxy-5-methylphenazinium methyl sulfate. The yield of formate and alkane per reduced PetF approaches its theoretical upper limit when reduction of the intermediate is carried out in the presence of FNR. Reduction of the intermediate by either system leads to accumulation of a substrate-derived peroxyl radical as a result of off-pathway trapping of the C2-alkyl radical intermediate by excess O2, which consequently diminishes the yield of the hydrocarbon product. A sulfinyl radical located on residue Cys71 also accumulates with short-chain aldehydes. The detection of these radicals under turnover conditions provides the most direct evidence to date for a free-radical mechanism. Additionally, our results expose an inefficiency of the enzyme in processing its radical intermediate, presenting a target for optimization of bioprocesses exploiting this hydrocarbon-production pathway.

  4. Systematic reduction of complex tropospheric chemical mechanisms, Part I: sensitivity and time-scale analyses

    Directory of Open Access Journals (Sweden)

    L. E. Whitehouse

    2004-01-01

    Full Text Available Explicit mechanisms describing the complex degradation pathways of atmospheric volatile organic compounds (VOCs are important, since they allow the study of the contribution of individual VOCS to secondary pollutant formation. They are computationally expensive to solve however, since they contain large numbers of species and a wide range of time-scales causing stiffness in the resulting equation systems. This paper and the following companion paper describe the application of systematic and automated methods for reducing such complex mechanisms, whilst maintaining the accuracy of the model with respect to important species and features. The methods are demonstrated via application to version 2 of the Leeds Master Chemical Mechanism. The methods of Jacobian analysis and overall rate sensitivity analysis proved to be efficient and capable of removing the majority of redundant reactions and species in the scheme across a wide range of conditions relevant to the polluted troposphere. The application of principal component analysis of the rate sensitivity matrix was computationally expensive due to its use of the decomposition of very large matrices, and did not produce significant reduction over and above the other sensitivity methods. The use of the quasi-steady state approximation (QSSA proved to be an extremely successful method of removing the fast time-scales within the system, as demonstrated by a local perturbation analysis at each stage of reduction. QSSA species were automatically selected via the calculation of instantaneous QSSA errors based on user-selected tolerances. The application of the QSSA led to the removal of a large number of alkoxy radicals and excited Criegee bi-radicals via reaction lumping. The resulting reduced mechanism was shown to reproduce the concentration profiles of the important species selected from the full mechanism over a wide range of conditions, including those outside of which the reduced mechanism was

  5. CdS sensitized TiO{sub 2} film for photocatalytic reduction of Cr(VI) by microwave-assisted chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinjuan; Pan, Likun, E-mail: lkpan@phy.ecnu.edu.cn; Lv, Tian; Sun, Zhuo

    2014-01-15

    Highlights: • CdS sensitized TiO{sub 2} films are synthesized by microwave-assisted deposition method. • The photocatalytic reduction of Cr(VI) by CdS sensitized TiO{sub 2} film is investigated. • A high Cr(VI) reduction rate of 93% is achieved under white LED light irradiation. -- Abstract: CdS quantum dots (QDs) sensitized TiO{sub 2} films were successfully synthesized using one-step microwave assisted chemical bath deposition method, which allows a facile and rapid deposition and integration between CdS QDs and TiO{sub 2} films. The photocatalytic performance of the films fabricated using CdS precursor solutions with different concentrations in the reduction of Cr(VI) under white light emitting diode (LED) light irradiation was investigated. The results show that the CdS sensitization can enhance the photocatalytic performance of TiO{sub 2} film with a maximum reduction rate of 93% for 240 min under white LED light irradiation as compared with the pure TiO{sub 2} film (31%) due to the increase of light absorption and the reduction of recombination of the injected electrons from CdS to TiO{sub 2}.

  6. Simultaneous nitrate reduction and acetaminophen oxidation using the continuous-flow chemical-less VUV process as an integrated advanced oxidation and reduction process

    Energy Technology Data Exchange (ETDEWEB)

    Moussavi, Gholamreza, E-mail: moussavi@modares.ac.ir; Shekoohiyan, Sakine

    2016-11-15

    Highlights: • Simultaneous advanced oxidation and reduction processes were explored in VUV system. • Complete reduction of nitrate to N{sub 2} was achieved at the presence of acetaminophen. • Complete degradation of acetaminophen was achieved at the presence of nitrate. • Over 95% of acetaminophen was mineralized in the VUV photoreactor. • VUV is a chemical-less advanced process for treating water emerging contaminants. - Abstract: This work was aimed at investigating the performance of the continuous-flow VUV photoreactor as a novel chemical-less advanced process for simultaneously oxidizing acetaminophen (ACT) as a model of pharmaceuticals and reducing nitrate in a single reactor. Solution pH was an important parameter affecting the performance of VUV; the highest ACT oxidation and nitrate reduction attained at solution pH between 6 and 8. The ACT was oxidized mainly by HO· while the aqueous electrons were the main working agents in the reduction of nitrate. The performance of VUV photoreactor improved with the increase of hydraulic retention time (HRT); the complete degradation of ACT and ∼99% reduction of nitrate with 100% N{sub 2} selectivity achieved at HRT of 80 min. The VUV effluent concentrations of nitrite and ammonium at HRT of 80 min were below the drinking water standards. The real water sample contaminated with the ACT and nitrate was efficiently treated in the VUV photoreactor. Therefore, the VUV photoreactor is a chemical-less advanced process in which both advanced oxidation and advanced reduction reactions are accomplished. This unique feature possesses VUV photoreactor as a promising method of treating water contaminated with both pharmaceutical and nitrate.

  7. A new rapid chemical route to prepare reduced graphene oxide using copper metal nanoparticles.

    Science.gov (United States)

    Wu, Tao; Gao, Jianping; Xu, Xiaoyang; Wang, Wei; Gao, Chunjuan; Qiu, Haixia

    2013-05-31

    Copper metal nanoparticles were used as a reducing agent to reduce graphene oxide (GO). The reaction was complete in about 10 min and did not involve the use of any toxic reagents or acids that are typically used in the reduction of GO by Zn and Fe powders. The high reduction activity of the Cu nanoparticles, compared to Cu powder, may be the result of the formation of Cu₂O nanoparticles. The effect of the mass ratio of the metal to GO for this reduction was also investigated. The reduction of the GO was verified by ultraviolet-visible absorption spectroscopy, x-ray diffraction, thermogravimetric analysis, Raman spectroscopy, x-ray photoelectron spectroscopy and transmission electron microscopy. After reduction, Cu₂O supported on reduced GO was formed and showed superior catalytic ability for the degradation of a model dye pollutant, methylene blue.

  8. Rapid and efficient photocatalytic reduction of hexavalent chromium by using “water dispersible” TiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei; Kang, Shi-Zhao, E-mail: kangsz@sit.edu.cn; Li, Xiangqing; Qin, Lixia; Yan, Hao; Mu, Jin, E-mail: mujin@sit.edu.cn

    2016-08-01

    In the present work, “water dispersible” TiO{sub 2} nanoparticles were prepared, and meanwhile, their photocatalytic activity was systematically tested for the reduction of aqueous Cr(VI) ions. It is found that the as-prepared “water dispersible” TiO{sub 2} nanoparticles are a highly efficient photocatalyst for the reduction of Cr(VI) ions in water under UV irradiation, and suitable for the remediation of Cr(VI) ions wastewater with low concentration. Compared with commercial TiO{sub 2} nanoparticles (P25), the “water dispersible” TiO{sub 2} nanoparticles exhibit 3.8-fold higher photocatalytic activity. 100% Cr (VI) ions can be reduced into Cr(III) ions within 10 min when the Cr (VI) ions initial concentration is 10 mg L{sup −1}. Moreover, the electrical energy consumption can be obviously decreased using the “water dispersible” TiO{sub 2} nanoparticles. These results suggest that the “water dispersible” TiO{sub 2} nanoparticles are a promising photocatalyst for rapid removal of Cr (VI) in environmental therapy. - Highlights: • “Water dispersible” TiO{sub 2} nanoparticles with high photocatalytic activity. • 100% Cr (VI) (10 mg L{sup −1}) can be reduced within 10 min. • Obvious decrease of electrical energy consumption.

  9. Optofluidic refractive-index sensors employing bent waveguide structures for low-cost, rapid chemical and biomedical sensing.

    Science.gov (United States)

    Liu, I-Chen; Chen, Pin-Chuan; Chau, Lai-Kwan; Chang, Guo-En

    2018-01-08

    We propose and develop an intensity-detection-based refractive-index (RI) sensor for low-cost, rapid RI sensing. The sensor is composed of a polymer bent ridge waveguide (BRWG) structure on a low-cost glass substrate and is integrated with a microfluidic channel. Different-RI solutions flowing through the BRWG sensing region induce output optical power variations caused by optical bend losses, enabling simple and real-time RI detection. Additionally, the sensors are fabricated using rapid and cost-effective vacuum-less processes, attaining the low cost and high throughput required for mass production. A good RI solution of 5.31 10-4 × RIU-1 is achieved from the RI experiments. This study demonstrates mass-producible and compact RI sensors for rapid and sensitive chemical analysis and biomedical sensing.

  10. Flow Alteration and Chemical Reduction: Air Stripping to Lessen Subsurface Discharges of Mercury to Surface Water

    Science.gov (United States)

    Brooks, S. C.; Bogle, M.; Liang, L.; Miller, C. L.; Peterson, M.; Southworth, G. R.; Spalding, B. P.

    2009-12-01

    process water. Greater than 90% of the mercury in that discharge was converted to the highly volatile dissolved Hg(0) by dechlorinating the streamflow with ascorbic acid and then treating it with a near stoichiometric concentration of the chemical reductant stannous chloride. Preliminary engineering evaluations indicate that once converted to Hg(0), mercury in the stream discharge could be removed by in-situ air stripping at the discharge point or perhaps within the enclosed stormdrain network upstream. If chemical reduction:air stripping was eventualy able to remove 80% or more of Hg from water, input to the stream from that source could be lowered from 6 - 8 g/d to 1 - 2 g/d. Together, these two strategies have the potential to eliminate much of the remaining dissolved Hg input to the creek.

  11. Ultrasound improves chemical reduction of natural contaminant microbiota and Salmonella enterica subsp. enterica on strawberries.

    Science.gov (United States)

    do Rosário, Denes Kaic Alves; da Silva Mutz, Yhan; Peixoto, Jaqueline Moreira Curtis; Oliveira, Syllas Borburema Silva; de Carvalho, Raquel Vieira; Carneiro, Joel Camilo Souza; de São José, Jackline Freitas Brilhante; Bernardes, Patrícia Campos

    2017-01-16

    New sanitization methods have been evaluated to improve food safety and food quality and to replace chlorine compounds. However, these new methods can lead to physicochemical and sensory changes in fruits and vegetables. The present study evaluated the effects of acetic acid, peracetic acid, and sodium dodecylbenzenesulfonate isolated or combined with 5min of ultrasound treatment (40kHz, 500W) on strawberry quality over 9days of storage at 8°C. The strawberry natural contaminant microbiota (molds and yeasts, mesophilic aerobic and lactic acid bacteria), physicochemical quality (pH, total titratable acidity, total soluble solids, vitamin C, and color), sensory quality (triangle test) and inactivation of Salmonella enterica subsp. enterica intentionally inoculated onto strawberries were analyzed. Ultrasound increased the effect of all chemical compounds in the reduction of aerobic mesophilic, molds and yeasts. The best treatment for those groups of microorganisms was ultrasound combined with peracetic acid (US+PA) that reduced 1.8 and 2.0logcfu/g during 9days of storage. Bactericidal effect of peracetic acid was also improved by ultrasound inactivation of S. enterica, reaching a decimal reduction of 2.1logcfu/g. Moreover, synergistic effects were observed in contaminant natural microbiota inactivation for all tested compounds during storage, without any major physicochemical or sensory alteration to the strawberries. Therefore, ultrasound treatment can improve the effect of sanitizers that are substitutes of chlorine compounds without altering the quality of strawberries during storage. Acetic acid (PubChem CID: 176); Peracetic acid (PubChem CID: 6585); Sodium dodecylbenzenesulfonate (PubChem CID: 18372154). Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Advanced Chemical Reduction of Reduced Graphene Oxide and Its Photocatalytic Activity in Degrading Reactive Black 5

    Directory of Open Access Journals (Sweden)

    Christelle Pau Ping Wong

    2015-10-01

    Full Text Available Textile industries consume large volumes of water for dye processing, leading to undesirable toxic dyes in water bodies. Dyestuffs are harmful to human health and aquatic life, and such illnesses as cholera, dysentery, hepatitis A, and hinder the photosynthetic activity of aquatic plants. To overcome this environmental problem, the advanced oxidation process is a promising technique to mineralize a wide range of dyes in water systems. In this work, reduced graphene oxide (rGO was prepared via an advanced chemical reduction route, and its photocatalytic activity was tested by photodegrading Reactive Black 5 (RB5 dye in aqueous solution. rGO was synthesized by dispersing the graphite oxide into the water to form a graphene oxide (GO solution followed by the addition of hydrazine. Graphite oxide was prepared using a modified Hummers’ method by using potassium permanganate and concentrated sulphuric acid. The resulted rGO nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV-Vis, X-ray powder diffraction (XRD, Raman, and Scanning Electron Microscopy (SEM to further investigate their chemical properties. A characteristic peak of rGO-48 h (275 cm−1 was observed in the UV spectrum. Further, the appearance of a broad peak (002, centred at 2θ = 24.1°, in XRD showing that graphene oxide was reduced to rGO. Based on our results, it was found that the resulted rGO-48 h nanoparticles achieved 49% photodecolorization of RB5 under UV irradiation at pH 3 in 60 min. This was attributed to the high and efficient electron transport behaviors of rGO between aromatic regions of rGO and RB5 molecules.

  13. LastQuake: a comprehensive strategy for rapid engagement of earthquake eyewitnesses, massive crowdsourcing and risk reduction

    Science.gov (United States)

    Bossu, R.; Roussel, F.; Mazet-Roux, G.; Steed, R.; Frobert, L.

    2015-12-01

    LastQuake is a smartphone app, browser add-on and the most sophisticated Twitter robot (quakebot) for earthquakes currently in operation. It fulfills eyewitnesses' needs by offering information on felt earthquakes and their effects within tens of seconds of their occurrence. Associated with an active presence on Facebook, Pinterest and on websites, this proves a very efficient engagement strategy. For example, the app was installed thousands of times after the Ghorka earthquake in Nepal. Language barriers have been erased by using visual communication; for example, felt reports are collected through a set of cartoons representing different shaking levels. Within 3 weeks of the magnitude 7.8 Ghorka earthquakes, 7,000 felt reports with thousands of comments were collected related to the mainshock and tens of its aftershocks as well as 100 informative geo-located pics. The QuakeBot was essential in allowing us to be identified so well and interact with those affected. LastQuake is also a risk reduction tool since it provides rapid information. Rapid information is similar to prevention since when it does not exist, disasters can happen. When no information is available after a felt earthquake, the public block emergency lines by trying to find out the cause of the shaking, crowds form potentially leading to unpredictable crowd movement, rumors spread. In its next release LastQuake will also provide people with guidance immediately after a shaking through a number of pop-up cartoons illustrating "do/don't do" items (go to open places, do not phone emergency services except if people are injured…). LastQuake's app design is simple and intuitive and has a global audience. It benefited from a crowdfunding campaign (and the support of the Fondation MAIF) and more improvements have been planned after an online feedback campaign organized in early June with the Ghorka earthquake eyewitnesses. LastQuake is also a seismic risk reduction tools thanks to its very rapid

  14. Rapid Electrochemical Detection and Identification of Microbiological and Chemical Contaminants for Manned Spaceflight Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A great deal of effort has gone into the development of point-of-use methods to meet the challenge of rapid bacterial identification for both environmental...

  15. Chemical Probes of Rapid Estrogen Signaling in Breast Cancer Treatment and Chemoprevention

    National Research Council Canada - National Science Library

    Weatherman, Rose V

    2007-01-01

    .... Over the course of the project, we synthesized and tested approximately 15 new estrogen receptor modulators, some with novel activity in terms of both classic transcriptional and rapid response modulation...

  16. Ni removal from aqueous solutions by chemical reduction: Impact of pH and pe in the presence of citrate.

    Science.gov (United States)

    Li, Chi-Wang; Yu, Jui-Hsuan; Liang, Yang-Min; Chou, Yi-Hsuan; Park, Hyung-June; Choo, Kwang-Ho; Chen, Shiao-Shing

    2016-12-15

    The chemical precipitation of Ni ions from industrial wastewater at alkaline pH values creates waste chemical sludge (e.g., Ni(OH)2). We herein focused on Ni removal via chemical reduction using dithionite, by converting Ni(II) to its elemental or other valuable forms. Without the presence of a chelator (e.g., citrate), the nickel reduction efficiency increased with increasing dithionite:Ni molar ratio, reaching ∼99% at ratios above 3:1. The effect of pH on Ni reduction was in agreement with the standard redox potentials (pe(0)) of dithionite, which became more negative with an increase in pH leading to greater Ni reduction efficiencies. With the formation of Ni-citrate chelates, however, the Ni reduction deteriorated. Elevated pH and temperature improved nickel reduction, due to the greater reducing power of dithionite. The optimal pH value for Ni(II) reduction was found to be ∼8. Injecting Cu seed particles enhanced the rate and amount of Ni reduced. NiS and Ni3S2 were identified in the crystal of the resulting solids by X-ray crystallography, and the presence of elemental Ni was explained by X-ray photoelectron spectroscopy. The chemical reduction of actual printed circuit board wastewater with the dithionite:Ni(II) molar ratio dose of 12:1 retrieved ∼99% nickel after 30-min reaction at 40°C. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. The association of the original OSHA chemical hazard communication standard with reductions in acute work injuries/illnesses in private industry and the industrial releases of chemical carcinogens.

    Science.gov (United States)

    Oleinick, Arthur

    2014-02-01

    OSHA predicted the original chemical Hazard Communication Standard (HCS) would cumulatively reduce the lost workday acute injury/illness rate for exposure events by 20% over 20 years and reduce exposure to chemical carcinogens. JoinPoint trend software identified changes in the rate of change of BLS rates for days away from work for acute injuries/illnesses during 1992-2009 for manufacturing and nonmanufacturing industries for both chemical, noxious or allergenic injury exposure events and All other exposure events. The annual percent change in the rates was used to adjust observed numbers of cases to estimate their association with the standard. A case-control study of EPA's Toxic Release Inventory 1988-2009 data compared carcinogen and non-carcinogens' releases. The study estimates that the HCS was associated with a reduction in the number of acute injuries/illnesses due to chemical injury exposure events over the background rate in the range 107,569-459,395 (Hudson method/modified BIC model) depending on whether the HCS is treated as a marginal or sole factor in the decrease. Carcinogen releases have declined at a substantially faster rate than control non-carcinogens. The previous HCS standard was associated with significant reductions in chemical event acute injuries/illnesses and chemical carcinogen exposures. © 2013 Wiley Periodicals, Inc.

  18. Chemical waste risk reduction and environmental impact generated by laboratory activities in research and teaching institutions

    Directory of Open Access Journals (Sweden)

    Elizabeth de Souza Nascimento

    2010-06-01

    Full Text Available The environmental impact caused by teaching and research with regard to chemical waste is of increasing concern, and attempts to solve the issue are being made. Education and research-related institutions, in most laboratory and non-laboratory activities, contribute to the generation of small quantities of waste, many of them highly toxic. Of this waste, some is listed by government agencies who are concerned about environmental pollution: disposal of acids, metals, solvents, chemicals and toxicity of selected products of synthesis, whose toxicity is often unknown. This article presents an assessment of the problem and identifies possible solutions, indicating pertinent laws, directives and guidelines; examples of institutions that have implemented protocols in order to minimize the generation of waste; harmonization of procedures for waste management and waste minimization procedures such as reduction, reuse and recycling of chemicals.O impacto ambiental acarretado por atividades de pesquisa e ensino no que se refere aos resíduos químicos vem sendo cada vez mais discutido e tentativas de solucionar a questão vêm sendo apresentadas. As instituições de ensino e pesquisa, em quase todas as atividades e não somente as laboratoriais, contribuem para a geração de pequenas quantidades de resíduos, muitos deles altamente tóxicos. Destes, alguns constam em listas de agências governamentais que se preocupam com a qualidade do meio ambiente: descartes de ácidos, metais, solventes, agentes químicos de elevada toxicidade e ainda os produtos de síntese, cuja toxicidade é frequentemente desconhecida. Este artigo apresenta uma avaliação do problema identificando possíveis soluções, a partir da apresentação de legislações pertinentes, exemplos de instituições que vêm implantando protocolos que minimizam a geração de resíduos, sistemas de harmonização de processos de gerenciamento de resíduos e procedimentos de minimização de

  19. Deposition of silver nanoparticles on multiwalled carbon nanotubes by chemical reduction process and their antimicrobial effects

    Energy Technology Data Exchange (ETDEWEB)

    Haider, Adawiya J., E-mail: adawiyahaider@yahoo.com [Nanotechnology and Advanced Materials Research Center, University of Technology, Baghdad, Republic of Iraq, 10066 (Iraq); Thamir, Amin D. [Production and Metallurgy department, University of Technology, University of Technology, Baghdad, Republic of Iraq, 10066 (Iraq); Ahmed, Duha S.; Mohammad, M. R. [Applied Physics department, University of Technology, University of Technology, Baghdad, Republic, of Iraq, 10066 (Iraq)

    2016-07-25

    In this paper, the functionalization of raw-MWCNTs involves oxidation reaction using concentrated acid mixture of HNO{sub 3}:H{sub 2}SO{sub 4} (1:3), via ultrasonic bath (170 W, 50 kHz) to obtain functional groups. Then Ag nanoparticles are decorated the outside over the surface of functionalized MWCNTs using a chemical reduction process resulting in the formation of(Ag/ MWCNTs) hybrid material. The results showed that outer diameter functionalized F-MWCNTs andAg nanoparticles size was about (11-80) nm and (10 to 25) nm, respectively using TEM and HRTEM. The crystallographic structure of MWCNTs using X-ray diffraction (XRD) analysis proved diffraction peaks at 38.1°, 44.3°, 64.7° and 77.4° degrees namely, Ag (111), Ag (200), Ag (220), and Ag (311) of the face-centered cubic lattice of Ag, respectively, excepting the peak at 2θ =25.6°, which correspond to the (0 0 2) reflection of the MWNTs are corresponding to Ag/MWNTs. The antimicrobial activities of Ag/MWCNTs hybrid using plate count method showed that decreasing a large number of bacteria colonies of E. coli and S. aureu with increasing the hybrid concentrations after incubation for 24 h in shaker incubator with percentage of inhibition approaching 100%.

  20. ZnO nanostructures with tunable visible luminescence: Effects of kinetics of chemical reduction and annealing

    Directory of Open Access Journals (Sweden)

    R. Raji

    2017-03-01

    Full Text Available Highly crystalline ZnO nanoparticles were synthesized using a co-precipitation method. The morphology and optical properties of these nanoparticles are found to be highly sensitive to the growth parameters such as the concentration of reducing agent and annealing temperature. Indeed, the concentration of the reducing agent can alter the morphology of nanoparticles from quasi-spherical to rod-like and then to flower-like structures. Attempts were made to tune the emission wavelength over the visible region by varying the kinetics of chemical reduction and annealing. The possibility of tuning the emission in a visible range from orange to red and then to green by changing the nature of defects by annealing is also reported. Analysis of the Raman spectrum, with its intensity observed at 580 cm−1 corresponding to E1 (LO mode, revealed that the kinetics and thermodynamics of formation and growth of these nanoparticles determined the nature and density of the probable defects such as oxygen vacancies, interstitial zinc atoms and their complexes.

  1. Chemically enhanced biological NOx removal from flue gases : nitric oxide and ferric EDTA reduction in BioDeNox reactors

    NARCIS (Netherlands)

    Maas, van der P.M.F.

    2005-01-01

    The emission of nitrogen oxides (NOx) to the atmosphere is a major environmental problem. To abate NOx emissions from industrial flue gases, to date, mainly chemical processes like selective catalytic reduction (SCR) are applied. All these processes require high temperatures (>300 °C) and

  2. Synthesis of Nanocobalt Powders for an Anode Material of Lithium-Ion Batteries by Chemical Reduction and Carbon Coating

    Directory of Open Access Journals (Sweden)

    Seong-Hyeon Hong

    2014-01-01

    Full Text Available Nanosized Co powders were prepared by a chemical reduction method with and without CTAB (cetyltrimethylammonium bromide, C19H42BrN and carbon-coating heat treatment at 700°C for 1 h, and the electrochemical properties of the prepared nanosized Co powders were examined to evaluate their suitability as an anode material of Li-ion batteries. Nanosized amorphous Co-based powders could be synthesized by a chemical reduction method in which a reducing agent is added to a Co ion-dissolved aqueous solution. When the prepared nanosized Co-based powders were subjected to carbon-coating heat treatment at 700°C for 1 h, the amorphous phase was crystallized, and a Co single phase could be obtained. The Co-based powder prepared by chemical reduction with CTAB and carbon-coating heat treatment had a smaller first discharge capacity (about 557 mAh/g than the Co-based powder prepared by chemical reduction without CTAB and carbon-coating heat treatment (about 628 mAh/g. However, the former had a better cycling performance than the latter from the third cycle. The carbon-coated layers are believed to have led to quite good cycling performances of the prepared Co-based powders from the third cycle.

  3. Reduction in ultrasonic vocalizations in pups born to rapid eye movement sleep restricted mothers in rat model.

    Directory of Open Access Journals (Sweden)

    Kamalesh K Gulia

    Full Text Available The effects of rapid eye movement sleep restriction (REMSR in rats during late pregnancy were studied on the ultrasonic vocalizations (USVs made by the pups. USVs are distress calls inaudible to human ears. Rapid eye movement (REM sleep was restricted in one group of pregnant rats for 22 hours, starting from gestational day 14 to 20, using standard single platform method. The USVs of male pups were recorded after a brief isolation from their mother for two minutes on alternate post-natal days, from day one till weaning. The USVs were recorded using microphones and were analysed qualitatively and quantitatively using SASPro software. Control pups produced maximum vocalization on post-natal days 9 to 11. In comparison, the pups born to REMSR mothers showed not only a reduction in vocalization but also a delay in peak call making days. The experimental group showed variations in the types and characteristics of call types, and alteration in temporal profile. The blunting of distress call making response in these pups indicates that maternal sleep plays a role in regulating the neural development involved in vocalizations and possibly in shaping the emotional behaviour in neonates. It is suggested that the reduced ultrasonic vocalizations can be utilized as a reliable early marker for affective state in rat pups. Such impaired vocalization responses could provide an important lead in understanding mother-child bonding for an optimal cognitive development during post-partum life. This is the first report showing a potential link between maternal REM sleep deprivation and the vocalization in neonates and infants.

  4. Reduction in ultrasonic vocalizations in pups born to rapid eye movement sleep restricted mothers in rat model.

    Science.gov (United States)

    Gulia, Kamalesh K; Patel, Niraj; Radhakrishnan, Arathi; Kumar, Velayudhan Mohan

    2014-01-01

    The effects of rapid eye movement sleep restriction (REMSR) in rats during late pregnancy were studied on the ultrasonic vocalizations (USVs) made by the pups. USVs are distress calls inaudible to human ears. Rapid eye movement (REM) sleep was restricted in one group of pregnant rats for 22 hours, starting from gestational day 14 to 20, using standard single platform method. The USVs of male pups were recorded after a brief isolation from their mother for two minutes on alternate post-natal days, from day one till weaning. The USVs were recorded using microphones and were analysed qualitatively and quantitatively using SASPro software. Control pups produced maximum vocalization on post-natal days 9 to 11. In comparison, the pups born to REMSR mothers showed not only a reduction in vocalization but also a delay in peak call making days. The experimental group showed variations in the types and characteristics of call types, and alteration in temporal profile. The blunting of distress call making response in these pups indicates that maternal sleep plays a role in regulating the neural development involved in vocalizations and possibly in shaping the emotional behaviour in neonates. It is suggested that the reduced ultrasonic vocalizations can be utilized as a reliable early marker for affective state in rat pups. Such impaired vocalization responses could provide an important lead in understanding mother-child bonding for an optimal cognitive development during post-partum life. This is the first report showing a potential link between maternal REM sleep deprivation and the vocalization in neonates and infants.

  5. Strategies for Rapid Muscle Fatigue Reduction during FES Exercise in Individuals with Spinal Cord Injury: A Systematic Review.

    Science.gov (United States)

    Ibitoye, Morufu Olusola; Hamzaid, Nur Azah; Hasnan, Nazirah; Abdul Wahab, Ahmad Khairi; Davis, Glen M

    2016-01-01

    Rapid muscle fatigue during functional electrical stimulation (FES)-evoked muscle contractions in individuals with spinal cord injury (SCI) is a significant limitation to attaining health benefits of FES-exercise. Delaying the onset of muscle fatigue is often cited as an important goal linked to FES clinical efficacy. Although the basic concept of fatigue-resistance has a long history, recent advances in biomedical engineering, physiotherapy and clinical exercise science have achieved improved clinical benefits, especially for reducing muscle fatigue during FES-exercise. This review evaluated the methodological quality of strategies underlying muscle fatigue-resistance that have been used to optimize FES therapeutic approaches. The review also sought to synthesize the effectiveness of these strategies for persons with SCI in order to establish their functional impacts and clinical relevance. Published scientific literature pertaining to the reduction of FES-induced muscle fatigue was identified through searches of the following databases: Science Direct, Medline, IEEE Xplore, SpringerLink, PubMed and Nature, from the earliest returned record until June 2015. Titles and abstracts were screened to obtain 35 studies that met the inclusion criteria for this systematic review. Following the evaluation of methodological quality (mean (SD), 50 (6) %) of the reviewed studies using the Downs and Black scale, the largest treatment effects reported to reduce muscle fatigue mainly investigated isometric contractions of limited functional and clinical relevance (n = 28). Some investigations (n = 13) lacked randomisation, while others were characterised by small sample sizes with low statistical power. Nevertheless, the clinical significance of emerging trends to improve fatigue-resistance during FES included (i) optimizing electrode positioning, (ii) fine-tuning of stimulation patterns and other FES parameters, (iii) adjustments to the mode and frequency of exercise training

  6. Strategies for Rapid Muscle Fatigue Reduction during FES Exercise in Individuals with Spinal Cord Injury: A Systematic Review.

    Directory of Open Access Journals (Sweden)

    Morufu Olusola Ibitoye

    Full Text Available Rapid muscle fatigue during functional electrical stimulation (FES-evoked muscle contractions in individuals with spinal cord injury (SCI is a significant limitation to attaining health benefits of FES-exercise. Delaying the onset of muscle fatigue is often cited as an important goal linked to FES clinical efficacy. Although the basic concept of fatigue-resistance has a long history, recent advances in biomedical engineering, physiotherapy and clinical exercise science have achieved improved clinical benefits, especially for reducing muscle fatigue during FES-exercise. This review evaluated the methodological quality of strategies underlying muscle fatigue-resistance that have been used to optimize FES therapeutic approaches. The review also sought to synthesize the effectiveness of these strategies for persons with SCI in order to establish their functional impacts and clinical relevance.Published scientific literature pertaining to the reduction of FES-induced muscle fatigue was identified through searches of the following databases: Science Direct, Medline, IEEE Xplore, SpringerLink, PubMed and Nature, from the earliest returned record until June 2015. Titles and abstracts were screened to obtain 35 studies that met the inclusion criteria for this systematic review.Following the evaluation of methodological quality (mean (SD, 50 (6 % of the reviewed studies using the Downs and Black scale, the largest treatment effects reported to reduce muscle fatigue mainly investigated isometric contractions of limited functional and clinical relevance (n = 28. Some investigations (n = 13 lacked randomisation, while others were characterised by small sample sizes with low statistical power. Nevertheless, the clinical significance of emerging trends to improve fatigue-resistance during FES included (i optimizing electrode positioning, (ii fine-tuning of stimulation patterns and other FES parameters, (iii adjustments to the mode and frequency of exercise

  7. Strategies for Rapid Muscle Fatigue Reduction during FES Exercise in Individuals with Spinal Cord Injury: A Systematic Review

    Science.gov (United States)

    Ibitoye, Morufu Olusola; Hamzaid, Nur Azah; Hasnan, Nazirah; Abdul Wahab, Ahmad Khairi; Davis, Glen M.

    2016-01-01

    Background Rapid muscle fatigue during functional electrical stimulation (FES)-evoked muscle contractions in individuals with spinal cord injury (SCI) is a significant limitation to attaining health benefits of FES-exercise. Delaying the onset of muscle fatigue is often cited as an important goal linked to FES clinical efficacy. Although the basic concept of fatigue-resistance has a long history, recent advances in biomedical engineering, physiotherapy and clinical exercise science have achieved improved clinical benefits, especially for reducing muscle fatigue during FES-exercise. This review evaluated the methodological quality of strategies underlying muscle fatigue-resistance that have been used to optimize FES therapeutic approaches. The review also sought to synthesize the effectiveness of these strategies for persons with SCI in order to establish their functional impacts and clinical relevance. Methods Published scientific literature pertaining to the reduction of FES-induced muscle fatigue was identified through searches of the following databases: Science Direct, Medline, IEEE Xplore, SpringerLink, PubMed and Nature, from the earliest returned record until June 2015. Titles and abstracts were screened to obtain 35 studies that met the inclusion criteria for this systematic review. Results Following the evaluation of methodological quality (mean (SD), 50 (6) %) of the reviewed studies using the Downs and Black scale, the largest treatment effects reported to reduce muscle fatigue mainly investigated isometric contractions of limited functional and clinical relevance (n = 28). Some investigations (n = 13) lacked randomisation, while others were characterised by small sample sizes with low statistical power. Nevertheless, the clinical significance of emerging trends to improve fatigue-resistance during FES included (i) optimizing electrode positioning, (ii) fine-tuning of stimulation patterns and other FES parameters, (iii) adjustments to the mode and

  8. [Rapid detection of four antipertensive chemicals adulterated in traditional Chinese medicine for hypertension using TLC-SERS].

    Science.gov (United States)

    Zhu, Qing-Xia; Cao, Yong-Bing; Cao, Ying-Ying; Lu, Feng

    2014-04-01

    A novel facile method for on-site detection of antipertensive chemicals (e. g. nicardipine hydrochloride, doxazosin mesylate, propranolol hydrochloride, and hydrochlorothiazide) adulterated in traditional Chinese medicine for hypertension using thin layer chromatography (TLC) combined with surface enhanced Raman spectroscopy (SERS) was reported in the present paper. Analytes and pharmaceutical matrices was separated by TLC, then SERS method was used to complete qualitative identification of trace substances on TLC plate. By optimizing colloidal silver concentration and developing solvent, as well as exploring the optimal limits of detection (LOD), the initially established TLC-SERS method was used to detect real hypertension Chinese pharmaceuticals. The results showed that this method had good specificity for the four chemicals and high sensitivity with a limit of detection as lower as to 0.005 microg. Finally, two of the ten antipertensive drugs were detected to be adulterated with chemicals. This simple and fast method can realize rapid detection of chemicals illegally for doping in antipertensive Chinese pharmaceuticals, and would have good prospects in on-site detection of chemicals for doping in Chinese pharmaceuticals.

  9. Rapid continuous chemical methods for studies of nuclei far from stability

    CERN Document Server

    Trautmann, N; Eriksen, D; Gaggeler, H; Greulich, N; Hickmann, U; Kaffrell, N; Skarnemark, G; Stender, E; Zendel, M

    1981-01-01

    Fast continuous separation methods accomplished by combining a gas-jet recoil-transport system with a variety of chemical systems are described. Procedures for the isolation of individual elements from fission product mixtures with the multistage solvent extraction facility SISAK are presented. Thermochromatography in connection with a gas-jet has been studied as a technique for on-line separation of volatile fission halides. Based on chemical reactions in a gas-jet system itself separation procedures for tellurium, selenium and germanium from fission products have been worked out. All the continuous chemical methods can be performed within a few seconds. The application of such procedures to the investigation of nuclides far from the line of beta -stability is illustrated by a few examples. (16 refs).

  10. Photochemical modeling in California with two chemical mechanisms: model intercomparison and response to emission reductions.

    Science.gov (United States)

    Cai, Chenxia; Kelly, James T; Avise, Jeremy C; Kaduwela, Ajith P; Stockwell, William R

    2011-05-01

    An updated version of the Statewide Air Pollution Research Center (SAPRC) chemical mechanism (SAPRC07C) was implemented into the Community Multiscale Air Quality (CMAQ) version 4.6. CMAQ simulations using SAPRC07C and the previously released version, SAPRC99, were performed and compared for an episode during July-August, 2000. Ozone (O3) predictions of the SAPRC07C simulation are generally lower than those of the SAPRC99 simulation in the key areas of central and southern California, especially in areas where modeled concentrations are greater than the federal 8-hr O3 standard of 75 parts per billion (ppb) and/or when the volatile organic compound (VOC)/nitrogen oxides (NOx) ratio is less than 13. The relative changes of ozone production efficiency (OPE) against the VOC/NOx ratio at 46 sites indicate that the OPE is reduced in SAPRC07C compared with SAPRC99 at most sites by as much as approximately 22%. The SAPRC99 and SAPRC07C mechanisms respond similarly to 20% reductions in anthropogenic VOC emissions. The response of the mechanisms to 20% NOx emissions reductions can be grouped into three cases. In case 1, in which both mechanisms show a decrease in daily maximum 8-hr O3 concentration with decreasing NOx emissions, the O3 decrease in SAPRC07C is smaller. In case 2, in which both mechanisms show an increase in O3 with decreasing NOx emissions, the O3 increase is larger in SAPRC07C. In case 3, SAPRC07C simulates an increase in O3 in response to reduced NOx emissions whereas SAPRC99 simulates a decrease in O3 for the same region. As a result, the areas where NOx controls would be disbeneficial are spatially expanded in SAPRC07C. Although the results presented here are valuable for understanding differences in predictions and model response for SAPRC99 and SAPRC07C, the study did not evaluate the impact of mechanism differences in the context of the U.S. Environmental Protection Agency's guidance for using numerical models in demonstrating air quality attainment

  11. Developing, Applying, and Evaluating Models for Rapid Screening of Chemical Exposures

    DEFF Research Database (Denmark)

    Arnot, J.; Shin, H.; Ernstoff, Alexi

    2015-01-01

    provides an introduction to underlying principles of some models used for exposure- and risk-based HTS for chemical prioritization for human health, including tools used in the ExpoDat project (USEtox, RAIDAR, CalTox) and other initiatives (SHEDS-HT). Case study examples of HTS include(i) model...

  12. Rapid Production of a Porous Cellulose Acetate Membrane for Water Filtration Using Readily Available Chemicals

    Science.gov (United States)

    Kaiser, Adrian; Stark, Wendelin J.; Grass, Robert N.

    2017-01-01

    A chemistry laboratory experiment using everyday items and readily available chemicals is described to introduce advanced high school students and undergraduate college students to porous polymer membranes. In a three-step manufacturing process, a membrane is produced at room temperature. The filtration principle of the membrane is then…

  13. Towards an integrated biosensor array for simultaneous and rapid multi-analysis of endocrine disrupting chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Scognamiglio, Viviana, E-mail: viviana.scognamiglio@mlib.ic.cnr.it [IC-CNR Istituto di Cristallografia, AdR1 Dipartimento Agroalimentare - Via Salaria Km 29.3 00015, Rome (Italy); Pezzotti, Italo; Pezzotti, Gianni; Cano, Juan; Manfredonia, Ivano [Biosensor S.r.l. - Via degli Olmetti 44 00060 Formello, Rome (Italy); Buonasera, Katia [IC-CNR Istituto di Cristallografia, AdR1 Dipartimento Agroalimentare - Via Salaria Km 29.3 00015, Rome (Italy); Arduini, Fabiana; Moscone, Danila; Palleschi, Giuseppe [Universita di Roma Tor Vergata, Dipartimento di Scienze e Tecnologie Chimiche - Via della Ricerca Scientifica 00133, Rome (Italy); Giardi, Maria Teresa [IC-CNR Istituto di Cristallografia, AdR1 Dipartimento Agroalimentare - Via Salaria Km 29.3 00015, Rome (Italy)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer A multitask biosensor for the detection of endocrine disrupting chemicals is proposed. Black-Right-Pointing-Pointer The sensing system employ an array of biological recognition elements. Black-Right-Pointing-Pointer Amperometric and optical transduction methods are provided in an integrated biosensor together with flow control systems. Black-Right-Pointing-Pointer The biosensing device results in an integrated, automatic and portable system for environmental and agrifood application. - Abstract: In this paper we propose the construction and application of a portable multi-purpose biosensor array for the simultaneous detection of a wide range of endocrine disruptor chemicals (EDCs), based on the recognition operated by various enzymes and microorganisms. The developed biosensor combines both electrochemical and optical transduction systems, in order to increase the number of chemical species which can be monitored. Considering to the maximum residue level (MRL) of contaminants established by the European Commission, the biosensor system was able to detect most of the chemicals analysed with very high sensitivity. In particular, atrazine and diuron were detected with a limit of detection of 0.5 nM, with an RSD% less than 5%; paraoxon and chlorpyrifos were revealed with a detection of 5 {mu}M and 4.5 {mu}M, respectively, with an RSD% less than 6%; catechol and bisphenol A were identified with a limit of detection of 1 {mu}M and 35 {mu}M respectively, with an RSD% less than 5%.

  14. Rapid Species-level Identification of Salvias by Chemometric Processing of Ambient Ionisation Mass Spectrometry-derived Chemical Profiles.

    Science.gov (United States)

    Giffen, Justine E; Lesiak, Ashton D; Dane, A John; Cody, Robert B; Musah, Rabi A

    2017-01-01

    The Salvia genus contains numerous economically important plants that have horticultural, culinary and nutraceutical uses. They are often similar in appearance, making species determination difficult. Species identification of dried Salvia products is also challenging since distinguishing plant morphological features are no longer present. The development of a simple high-throughput method of analysis of fresh and dried Salvia leaves that would permit rapid species-level identification and detection of diagnostic biomarkers. Plant leaves were analysed in their native form by DART-MS without the need for any sample preparation steps. This furnished chemical fingerprints characteristic of each species. In the same experiment, in-source collision-induced dissociation was used to identify biomarkers. Biomarker presence was also independently confirmed by GC-MS. Chemometric processing of DART-MS profiles was performed by kernel discriminant analysis (KDA) and soft independent modelling of class analogy (SIMCA) to classify the fingerprints according to species. The approach was successful despite the occurrence of diurnal cycle and plant-age related chemical profile variations within species. In a single rapid experiment, the presence of essential oil biomarkers such as 3-carene, α-pinene, β-pinene, β-thujone, β-caryophyllene, camphor and borneol could be confirmed. The method was applied to rapid identification and differentiation of Salvia apiana, S. dominica, S. elegans, S. officinalis, S. farinacea and S. patens. Species-level identification of Salvia plant material could be accomplished by chemometric processing of DART-HRMS-derived chemical profiles of both fresh and dried Salvia material. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. A rapidly deployable chemical sensing network for the real-time monitoring of toxic airborne contaminant releases in urban environments

    Science.gov (United States)

    Lepley, Jason J.; Lloyd, David R.

    2010-04-01

    We present findings of the DYCE project, which addresses the needs of military and blue light responders in providing a rapid, reliable on-scene analysis of the dispersion of toxic airborne contaminants following their malicious or accidental release into a rural, urban or industrial environment. We describe the development of a small network of ad-hoc deployable chemical and meteorological sensors capable of identifying and locating the source of the contaminant release, as well as monitoring and estimating the dispersion characteristics of the plume. We further present deployment planning methodologies to optimize the data gathering mission given a constrained asset base.

  16. Rapid yeast DNA extraction by boiling and freeze-thawing without using chemical reagents and DNA purification

    Directory of Open Access Journals (Sweden)

    Gildo Almeida da Silva

    2012-04-01

    Full Text Available The purpose of this work was to study a rapid yeast DNA extraction by boiling and freeze-thawing processes without using chemical reagents or any purification procedures, to obtain a high grade PCR-product. A specific DNA fragment of the 18S region of Dekkera bruxellensis and Saccharomyces cerevisiae was chosen. The described boiling and freeze-thawing protocols generated the PCR-grade product preparations and could be used to process many samples. The amplification of the fragments could be observed after 30 and 35 cycles. These processes of extraction without using any kind of chemical reagents, especial water, and purification procedures proved to be efficient, reproducible, simple, fast, and inexpensive.

  17. A Rapid Chemical Analysis of the Ingredients of NOL-130 Primer Mix

    Science.gov (United States)

    1979-12-01

    potassium chlorate, copper (I) thiocyanate, antimony sulfide, lead azide, and mercury fulminate . Wild (refs. 2,3) developed a method for tetracene based...on its dissolution in hydrochloric acid to give a well-defined reduction wave at the dropping mercury electrode. He also developed a method for the...374 Polarographic Analyzer (Princeton Applied Research Corporation, Princeton, NJ) and a model 303 Static Mercury Drop Electrode. For this work, the

  18. An improved technique for the rapid chemical characterisation of bacterial terpene cyclases.

    Science.gov (United States)

    Dickschat, Jeroen S; Pahirulzaman, Khomaizon A K; Rabe, Patrick; Klapschinski, Tim A

    2014-04-14

    A derivative of the pET28c(+) expression vector was constructed. It contains a yeast replication system (2μ origin of replication) and a yeast selectable marker (URA3), and can be used for gene cloning in yeast by efficient homologous recombination, and for heterologous expression in E. coli. The vector was used for the expression and chemical characterisation of three bacterial terpene cyclases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. A rapid chemical method for lysing Arabidopsis cells for protein analysis

    OpenAIRE

    Takano Tetsuo; Liu Shenkui; Tsugama Daisuke

    2011-01-01

    Abstract Background Protein extraction is a frequent procedure in biological research. For preparation of plant cell extracts, plant materials usually have to be ground and homogenized to physically break the robust cell wall, but this step is laborious and time-consuming when a large number of samples are handled at once. Results We developed a chemical method for lysing Arabidopsis cells without grinding. In this method, plants are boiled for just 10 minutes in a solution containing a Ca2+ ...

  20. Rapid and highly efficient growth of graphene on copper by chemical vapor deposition of ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Lisi, Nicola, E-mail: nicola.lisi@enea.it [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Buonocore, Francesco; Dikonimos, Theodoros; Leoni, Enrico [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Faggio, Giuliana; Messina, Giacomo [Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Università “Mediterranea” di Reggio Calabria, 89122 Reggio Calabria (Italy); Morandi, Vittorio; Ortolani, Luca [CNR-IMM Bologna, Via Gobetti 101, 40129 Bologna (Italy); Capasso, Andrea [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy)

    2014-11-28

    The growth of graphene by chemical vapor deposition on metal foils is a promising technique to deliver large-area films with high electron mobility. Nowadays, the chemical vapor deposition of hydrocarbons on copper is the most investigated synthesis method, although many other carbon precursors and metal substrates are used too. Among these, ethanol is a safe and inexpensive precursor that seems to offer favorable synthesis kinetics. We explored the growth of graphene on copper from ethanol, focusing on processes of short duration (up to one min). We investigated the produced films by electron microscopy, Raman and X-ray photoemission spectroscopy. A graphene film with high crystalline quality was found to cover the entire copper catalyst substrate in just 20 s, making ethanol appear as a more efficient carbon feedstock than methane and other commonly used precursors. - Highlights: • Graphene films were grown by fast chemical vapor deposition of ethanol on copper. • High-temperature/short-time growth produced highly crystalline graphene. • The copper substrate was entirely covered by a graphene film in just 20 s. • Addition of H{sub 2} had a negligible effect on the crystalline quality.

  1. Rapid stress system drives chemical transfer of fear from sender to receiver.

    Directory of Open Access Journals (Sweden)

    Jasper H B de Groot

    Full Text Available Humans can register another person's fear not only with their eyes and ears, but also with their nose. Previous research has demonstrated that exposure to body odors from fearful individuals elicited implicit fear in others. The odor of fearful individuals appears to have a distinctive signature that can be produced relatively rapidly, driven by a physiological mechanism that has remained unexplored in earlier research. The apocrine sweat glands in the armpit that are responsible for chemosignal production contain receptors for adrenalin. We therefore expected that the release of adrenalin through activation of the rapid stress response system (i.e., the sympathetic-adrenal medullary system is what drives the release of fear sweat, as opposed to activation of the slower stress response system (i.e., hypothalamus-pituitary-adrenal axis. To test this assumption, sweat was sampled while eight participants prepared for a speech. Participants had higher heart rates and produced more armpit sweat in the fast stress condition, compared to baseline and the slow stress condition. Importantly, exposure to sweat from participants in the fast stress condition induced in receivers (N = 31 a simulacrum of the state of the sender, evidenced by the emergence of a fearful facial expression (facial electromyography and vigilant behavior (i.e., faster classification of emotional facial expressions.

  2. Chemically synthesized PbS Nano particulate thin films for a rapid NO2 gas sensor

    Directory of Open Access Journals (Sweden)

    Burungale Vishal V.

    2016-03-01

    Full Text Available Rapid NO2 gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO2 gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO2 gas was measured at different operating temperatures, from 50 to 200 °C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 °C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO2 at 150 °C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.

  3. Quantitative analysis of lipid droplet fusion: inefficient steady state fusion but rapid stimulation by chemical fusogens.

    Directory of Open Access Journals (Sweden)

    Samantha Murphy

    Full Text Available Lipid droplets (LDs are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, a process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods and real-time analysis, we now show that LDs in diverse cell types show low constitutive fusogenic activity under normal growth conditions. To investigate the possible modulation of LD fusion, we screened for agents that can trigger fusion. A number of pharmacological agents caused homotypic fusion of lipid droplets in a variety of cell types. This provided a novel cell system to study rapid regulated fusion between homotypic phospholipid monolayers. LD fusion involved an initial step in which the two adjacent membranes became continuous (<10 s, followed by the slower merging (100 s of the neutral lipid cores to produce a single spherical LD. These fusion events were accompanied by changes to the LD surface organization. Measurements of LDs undergoing homotypic fusion showed that fused LDs maintained their initial volume, with a corresponding decrease in surface area suggesting rapid removal of membrane from the fused LD. This study provides estimates for the level of constitutive LD fusion in cells and questions the role of LD fusion in vivo. In addition, it highlights the extent of LD restructuring which occurs when homotypic LD fusion is triggered in a variety of cell types.

  4. Quantitative analysis of lipid droplet fusion: inefficient steady state fusion but rapid stimulation by chemical fusogens.

    Science.gov (United States)

    Murphy, Samantha; Martin, Sally; Parton, Robert G

    2010-12-23

    Lipid droplets (LDs) are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, a process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods and real-time analysis, we now show that LDs in diverse cell types show low constitutive fusogenic activity under normal growth conditions. To investigate the possible modulation of LD fusion, we screened for agents that can trigger fusion. A number of pharmacological agents caused homotypic fusion of lipid droplets in a variety of cell types. This provided a novel cell system to study rapid regulated fusion between homotypic phospholipid monolayers. LD fusion involved an initial step in which the two adjacent membranes became continuous (lipid cores to produce a single spherical LD. These fusion events were accompanied by changes to the LD surface organization. Measurements of LDs undergoing homotypic fusion showed that fused LDs maintained their initial volume, with a corresponding decrease in surface area suggesting rapid removal of membrane from the fused LD. This study provides estimates for the level of constitutive LD fusion in cells and questions the role of LD fusion in vivo. In addition, it highlights the extent of LD restructuring which occurs when homotypic LD fusion is triggered in a variety of cell types.

  5. Chemical Screening Method for the Rapid Identification of Microbial Sources of Marine Invertebrate-Associated Metabolites

    Directory of Open Access Journals (Sweden)

    Russell G. Kerr

    2011-03-01

    Full Text Available Marine invertebrates have proven to be a rich source of secondary metabolites. The growing recognition that marine microorganisms associated with invertebrate hosts are involved in the biosynthesis of secondary metabolites offers new alternatives for the discovery and development of marine natural products. However, the discovery of microorganisms producing secondary metabolites previously attributed to an invertebrate host poses a significant challenge. This study describes an efficient chemical screening method utilizing a 96-well plate-based bacterial cultivation strategy to identify and isolate microbial producers of marine invertebrate-associated metabolites.

  6. Rapid identification and quantitative analysis of chemical constituents of Gentiana veitchiorum by UHPLC-PDA-QTOF-MS

    Directory of Open Access Journals (Sweden)

    Shan Li

    Full Text Available ABSTRACT Gentiana veitchiorum Hemsl., Gentianaceae, a traditional Tibetan medicine, was used for the treatment of liver jaundice with damp-heat pathogen, as well as for headache and chronic pharyngitis. A rapid ultra-performance liquid chromatography, photodiode array detector, quadrupole time-of-flight mass spectrometry method was developed for the fast and accurate identification and quantification of the chemical constituents of G. veitchiorum. In fact, eighteen compounds were detected and identified on the basis of their mass spectra, fragment characteristics and comparison with published data. Especially, the MS fragmentation pathways of iridoid glycosides and flavone C-glycosides were illustrated. Five compounds among them were quantified by UHPLC-PDA, including swertiamarin, gentiopicroside, sweroside, isoorientin, and isovitexin. The proposed method was then validated based on the analyses of linearity, accuracy, precision, and recovery. The overall recoveries for the five analytes ranged from 96.54% to 100.81%, with RSD from 1.05% to 1.82%. In addition, ten batches of G. veitchiorum from different areas were also analyzed. The developed method was rapid and reliable for both identification and quantification of the chemical constituents of G. veitchiorum, especially for simultaneous qualitative and quantitative analysis of iridoid glycosides and flavone C-glycosides.

  7. Effectiveness of different chemical agents in rapid decontamination of gutta-percha cones

    Directory of Open Access Journals (Sweden)

    Cardoso Celso Luíz

    2000-01-01

    Full Text Available The effectiveness of seven disinfectant compounds used in dentistry for a rapid decontamination of 32 gutta-percha cones adhered with Staphylococcus aureus, Enterococcus faecalis, Escherichia coli strains or Bacillus subtilis spores was compared. Cones were treated with 2% glutaraldehyde, 1% sodium hypochlorite, 70% ethyl alcohol, 1% and 0.3% iodine alcohol, 2% chlorhexidine, 6% hydrogen peroxide, and 10% polyvinylpyrrolidone-iodine, for 1, 5, 10, and 15 minutes. After treatment, each cone was transferred to thioglycollate broth and incubated at 37ºC for 7 days. The products were bactericidal after 1 to 5 minutes and, with exception of ethyl alcohol and iodine-alcohol, sporicidal after 1 to 15 minutes of exposure. Results suggest that chlorhexidine, sodium hypochlorite, polyvinylpyrrolidone-iodine, hydrogen peroxide, and glutaraldehyde were the most effective products in the decontamination of gutta-percha cones.

  8. The evolution of structural and chemical heterogeneity during rapid solidification at gas atomization

    Science.gov (United States)

    Golod, V. M.; Sufiiarov, V. Sh

    2017-04-01

    Gas atomization is a high-performance process for manufacturing superfine metal powders. Formation of the powder particles takes place primarily through the fragmentation of alloy melt flow with high-pressure inert gas, which leads to the formation of non-uniform sized micron-scale particles and subsequent their rapid solidification due to heat exchange with gas environment. The article presents results of computer modeling of crystallization process, simulation and experimental studies of the cellular-dendrite structure formation and microsegregation in different size particles. It presents results of adaptation of the approach for local nonequilibrium solidification to conditions of crystallization at gas atomization, detected border values of the particle size at which it is possible a manifestation of diffusionless crystallization.

  9. Management of change: Lessons learned from staff reductions in the chemical process industry

    NARCIS (Netherlands)

    Zwetsloot, G.I.J.M.; Gort, J.; Steijger, N.; Moonen, C.

    2007-01-01

    Increasing global competition and shareholder pressure are causing major changes in the chemical industry. Over the last decade companies have been continuously improving staff efficiency. As a result, most modern chemical plants can be regarded as lean. Plans to further reduce the number of staff

  10. Hydrogen storage in multi-walled carbon nanotubes decorated with palladium nanoparticles using laser ablation/chemical reduction methods

    Science.gov (United States)

    Mehrabi, M.; Parvin, P.; Reyhani, A.; Mortazavi, S. Z.

    2017-09-01

    Hydrogen storage properties of multi-walled carbon nanotubes (MWCNTs) decorated by palladium nanoparticles (Pd NPs) are investigated using laser ablation and chemical reduction methods, revealing great differences between the two techniques. In the case of laser ablation, the hydrogen uptake is elevated with the Pd content up to a certain value and then undergoes a notable drop, whereas the hydrogen content linearly scales up with the Pd loading during the chemical reduction method. When the Pd loading is low, the storage capacity of the laser treated samples is higher than those decorated via the other technique of interest. During laser ablation, the larger Pd content is accompanied by plentiful pore formation, leading to larger pore sizes at higher doses, which seriously reduces the hydrogen uptake. Moreover, the desorption temperature of hydrogen notably increases in terms of Pd loading. In comparison, the laser ablation method undergoes a relatively smaller desorption temperature, mainly due to the larger pore size/volume.

  11. A tree-based method for the rapid screening of chemical fingerprints

    Directory of Open Access Journals (Sweden)

    Pedersen Christian NS

    2010-01-01

    Full Text Available Abstract Background The fingerprint of a molecule is a bitstring based on its structure, constructed such that structurally similar molecules will have similar fingerprints. Molecular fingerprints can be used in an initial phase of drug development for identifying novel drug candidates by screening large databases for molecules with fingerprints similar to a query fingerprint. Results In this paper, we present a method which efficiently finds all fingerprints in a database with Tanimoto coefficient to the query fingerprint above a user defined threshold. The method is based on two novel data structures for rapid screening of large databases: the kD grid and the Multibit tree. The kD grid is based on splitting the fingerprints into k shorter bitstrings and utilising these to compute bounds on the similarity of the complete bitstrings. The Multibit tree uses hierarchical clustering and similarity within each cluster to compute similar bounds. We have implemented our method and tested it on a large real-world data set. Our experiments show that our method yields approximately a three-fold speed-up over previous methods. Conclusions Using the novel kD grid and Multibit tree significantly reduce the time needed for searching databases of fingerprints. This will allow researchers to (1 perform more searches than previously possible and (2 to easily search large databases.

  12. UPLC-QTOF-MS with chemical profiling approach for rapidly evaluating chemical consistency between traditional and dispensing granule decoctions of Tao-Hong-Si-Wu decoction

    Directory of Open Access Journals (Sweden)

    Shang Erxin

    2012-11-01

    Full Text Available Abstract Background In the present study, chemical consistency between traditional and dispensing granule decoctions of Tao-Hong-Si-Wu decoction was rapidly evaluated by UPLC-QTOF-MS coupled with the MarkerLynx software. Two different kinds of decoctions, namely traditional decoction: water extract of mixed six constituent herbs of Tao-Hong-Si-Wu decoction, and dispensing granules decoction: mixed water extract of each individual herbs of Tao-Hong-Si-Wu decoction, were prepared. Results Chemical difference was found between traditional and dispensing granule decoctions, and albiflorin, paeoniflorin, gallic acid, amygdalin, and hydroxysafflor yellow A were identified as the significantly changed components during decocting Tao-Hong-Si-Wu decoction. All the peaks of mass spectrum from Tao-Hong-Si-Wu decoction and each herb were extracted and integration by using QuanLynx™. And the optimized data was used for linear regression analysis. The contribution of each herb in Tao-Hong-Si-Wu decoction, and the optimal compatibility proportion of dispensing granule decoction were derived from the linear regression equation. Conclusions The optimal dosage proportionality of Tao-Hong-Si-Wu dispensing granule decoction was obtained as 2.5:0.2:1:0.5:0.6:0.1 (DG : CX : BS : SD : TR : HH, which guided better clinic application of Tao-Hong-Si-Wu decoction as dispensing granule decoctions usage, and it also provided some experimental data to reveal the compatibility rule of the relative TCM formulae.

  13. Rapid determination of the chemical oxygen demand of water using a thermal biosensor.

    Science.gov (United States)

    Yao, Na; Wang, Jinqi; Zhou, Yikai

    2014-06-06

    In this paper we describe a thermal biosensor with a flow injection analysis system for the determination of the chemical oxygen demand (COD) of water samples. Glucose solutions of different concentrations and actual water samples were tested, and their COD values were determined by measuring the heat generated when the samples passed through a column containing periodic acid. The biosensor exhibited a large linear range (5 to 3000 mg/L) and a low detection limit (1.84 mg/L). It could tolerate the presence of chloride ions in concentrations of 0.015 M without requiring a masking agent. The sensor was successfully used for detecting the COD values of actual samples. The COD values of water samples from various sources were correlated with those obtained by the standard dichromate method; the linear regression coefficient was found to be 0.996. The sensor is environmentally friendly, economical, and highly stable, and exhibits good reproducibility and accuracy. In addition, its response time is short, and there is no danger of hazardous emissions or external contamination. Finally, the samples to be tested do not have to be pretreated. These results suggest that the biosensor is suitable for the continuous monitoring of the COD values of actual wastewater samples.

  14. Thermal and chemical diffusion in the rapid solidification of binary alloys

    Science.gov (United States)

    Conti

    2000-01-01

    Solidification of binary alloys is characterized by the necessity to reject away from the advancing front two conserved quantities: the latent heat released at the solid-liquid interface and the solute atoms that cannot be accommodated in the solid phase. As thermal diffusion is much faster than chemical diffusion, the latter is generally assumed to be the rate limiting mechanism for the process, and the problem is addressed through the isothermal approximation. In the present paper we use the phase-field model to study the planar growth of a solid germ, nucleated in its undercooled melt. We focus on the effects of a noninstantaneous thermal relaxation. The steady growth predicted at large supersaturation in the isothermal limit is prevented. Depending on the value of the Lewis number the growth rate is limited by either mass or heat diffusion; in the latter case we observe a sharp transition between two different regimes, in which originates a nonmonotonic time dependence of the interface temperature. The effects of this transition reflect in the composition of the solidified alloy.

  15. Major reduction in anti-malarial drug consumption in Senegal after nation-wide introduction of malaria rapid diagnostic tests.

    Directory of Open Access Journals (Sweden)

    Sylla Thiam

    Full Text Available BACKGROUND: While WHO recently recommended universal parasitological confirmation of suspected malaria prior to treatment, debate has continued as to whether wide-scale use of rapid diagnostic tests (RDTs can achieve this goal. Adherence of health service personnel to RDT results has been poor in some settings, with little impact on anti-malarial drug consumption. The Senegal national malaria control programme introduced universal parasite-based diagnosis using malaria RDTs from late 2007 in all public health facilities. This paper assesses the impact of this programme on anti-malarial drug consumption and disease reporting. METHODS AND FINDINGS: Nationally-collated programme data from 2007 to 2009 including malaria diagnostic outcomes, prescription of artemisinin-based combination therapy (ACT and consumption of RDTs in public health facilities, were reviewed and compared. Against a marked seasonal variation in all-cause out-patient visits, non-malarial fever and confirmed malaria, parasite-based diagnosis increased nationally from 3.9% of reported malaria-like febrile illness to 86.0% over a 3 year period. The prescription of ACT dropped throughout this period from 72.9% of malaria-like febrile illness to 31.5%, reaching close equivalence to confirmed malaria (29.9% of 584,873 suspect fever cases. An estimated 516,576 courses of inappropriate ACT prescription were averted. CONCLUSIONS: The data indicate high adherence of anti-malarial prescribing practice to RDT results after an initial run-in period. The large reduction in ACT consumption enabled by the move from symptom-based to parasite-based diagnosis demonstrates that effective roll-out and use of malaria RDTs is achievable on a national scale through well planned and structured implementation. While more detailed information on management of parasite-negative cases is required at point of care level to assess overall cost-benefits to the health sector, considerable cost-savings were

  16. Major reduction in anti-malarial drug consumption in Senegal after nation-wide introduction of malaria rapid diagnostic tests.

    Science.gov (United States)

    Thiam, Sylla; Thior, Moussa; Faye, Babacar; Ndiop, Médoune; Diouf, Mamadou Lamine; Diouf, Mame Birame; Diallo, Ibrahima; Fall, Fatou Ba; Ndiaye, Jean Louis; Albertini, Audrey; Lee, Evan; Jorgensen, Pernille; Gaye, Oumar; Bell, David

    2011-04-06

    While WHO recently recommended universal parasitological confirmation of suspected malaria prior to treatment, debate has continued as to whether wide-scale use of rapid diagnostic tests (RDTs) can achieve this goal. Adherence of health service personnel to RDT results has been poor in some settings, with little impact on anti-malarial drug consumption. The Senegal national malaria control programme introduced universal parasite-based diagnosis using malaria RDTs from late 2007 in all public health facilities. This paper assesses the impact of this programme on anti-malarial drug consumption and disease reporting. Nationally-collated programme data from 2007 to 2009 including malaria diagnostic outcomes, prescription of artemisinin-based combination therapy (ACT) and consumption of RDTs in public health facilities, were reviewed and compared. Against a marked seasonal variation in all-cause out-patient visits, non-malarial fever and confirmed malaria, parasite-based diagnosis increased nationally from 3.9% of reported malaria-like febrile illness to 86.0% over a 3 year period. The prescription of ACT dropped throughout this period from 72.9% of malaria-like febrile illness to 31.5%, reaching close equivalence to confirmed malaria (29.9% of 584,873 suspect fever cases). An estimated 516,576 courses of inappropriate ACT prescription were averted. The data indicate high adherence of anti-malarial prescribing practice to RDT results after an initial run-in period. The large reduction in ACT consumption enabled by the move from symptom-based to parasite-based diagnosis demonstrates that effective roll-out and use of malaria RDTs is achievable on a national scale through well planned and structured implementation. While more detailed information on management of parasite-negative cases is required at point of care level to assess overall cost-benefits to the health sector, considerable cost-savings were achieved in ACT procurement. Programmes need to be allowed

  17. Rapid screening of N-oxides of chemical warfare agents degradation products by ESI-tandem mass spectrometry.

    Science.gov (United States)

    Sridhar, L; Karthikraj, R; Lakshmi, V V S; Raju, N Prasada; Prabhakar, S

    2014-08-01

    Rapid detection and identification of chemical warfare agents and related precursors/degradation products in various environmental matrices is of paramount importance for verification of standards set by the chemical weapons convention (CWC). Nitrogen mustards, N,N-dialkylaminoethyl-2-chlorides, N,N-dialkylaminoethanols, N-alkyldiethanolamines, and triethanolamine, which are listed CWC scheduled chemicals, are prone to undergo N-oxidation in environmental matrices or during decontamination process. Thus, screening of the oxidized products of these compounds is also an important task in the verification process because the presence of these products reveals alleged use of nitrogen mustards or precursors of VX compounds. The N-oxides of aminoethanols and aminoethylchlorides easily produce [M + H](+) ions under electrospray ionization conditions, and their collision-induced dissociation spectra include a specific neutral loss of 48 u (OH + CH2OH) and 66 u (OH + CH2Cl), respectively. Based on this specific fragmentation, a rapid screening method was developed for screening of the N-oxides by applying neutral loss scan technique. The method was validated and the applicability of the method was demonstrated by analyzing positive and negative samples. The method was useful in the detection of N-oxides of aminoethanols and aminoethylchlorides in environmental matrices at trace levels (LOD, up to 500 ppb), even in the presence of complex masking agents, without the use of time-consuming sample preparation methods and chromatographic steps. This method is advantageous for the off-site verification program and also for participation in official proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW), the Netherlands. The structure of N-oxides can be confirmed by the MS/MS experiments on the detected peaks. A liquid chromatography-mass spectrometry (LC-MS) method was developed for the separation of isomeric N-oxides of aminoethanols and

  18. An alternative chemical redox method for the production of bispecific antibodies: implication in rapid detection of food borne pathogens.

    Directory of Open Access Journals (Sweden)

    Mohammad Owais

    Full Text Available Bi-functional antibodies with the ability to bind two unrelated epitopes have remarkable potential in diagnostic and bio-sensing applications. In the present study, bispecific antibodies that recognize human red blood cell (RBC and the food borne pathogen Listeria monocytogenes (L. monocytogenes were engineered. The procedure involves initial reduction of a mixture of anti-RBC and anti-Listeria antibodies followed by gradual re-oxidation of the reduced disulphides. This facilitates association of the separated antibody chains and formation of hybrid immunoglobulins with affinity for the L. monocytogenes and human RBC. The bispecific antibodies caused the agglutination of the RBCs only in the presence of L. monocytogenes cells. The agglutination process necessitated the specific presence of L. monocytogenes and the red colored clumps formed were readily visible with naked eyes. The RBC agglutination assay described here provides a remarkably simple approach for the rapid and highly specific screening of various pathogens in their biological niches.

  19. Rapid monitoring of mercury in air from an organic chemical factory in China using a portable mercury analyzer.

    Science.gov (United States)

    Yasutake, Akira; Cheng, Jin Ping; Kiyono, Masako; Uraguchi, Shimpei; Liu, Xiaojie; Miura, Kyoko; Yasuda, Yoshiaki; Mashyanov, Nikolay

    2011-01-01

    A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m(3) in air over the contaminated area provided evidence of the mercury transformation to volatile Hg(0). Mercury analysis of soil and plant samples demonstrated that the mercury concentrations in soil with vaporized and plant-absorbable forms were higher in the southern area, which was closer to the factory. Our results suggest that air monitoring using a portable mercury analyzer can be a convenient and useful method for the rapid detection and mapping of mercury pollution in advanced field surveys.

  20. Rapid Monitoring of Mercury in Air from an Organic Chemical Factory in China Using a Portable Mercury Analyzer

    Directory of Open Access Journals (Sweden)

    Akira Yasutake

    2011-01-01

    Full Text Available A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m3 in air over the contaminated area provided evidence of the mercury transformation to volatile Hg(0. Mercury analysis of soil and plant samples demonstrated that the mercury concentrations in soil with vaporized and plant-absorbable forms were higher in the southern area, which was closer to the factory. Our results suggest that air monitoring using a portable mercury analyzer can be a convenient and useful method for the rapid detection and mapping of mercury pollution in advanced field surveys.

  1. Combination of Cooling Curve and Micro-Chemical Phase Analysis of Rapidly Quenched Magnesium AM60B Alloy

    Science.gov (United States)

    Marchwica, P. C.; Gesing, A. J.; Sokolowski, J. H.; Blawert, C.; Jekl, J.; Berkmortel, R.

    Macro test samples of magnesium alloy AM60B were melted and quenched at maximum instantaneous cooling rates ranging from -5°C/s to -500°C/s and the resultant cooling curves were analyzed. Characteristic reactions on these curves corresponding to formation of individual phases were identified with the aid of literature data as well as metallographic and micro-chemical analysis. The results indicate that these phases, their size and location in the micro structure, their chemistry and their relative proportions all change in response to the increase in the cooling rate. These rapid cooling rates are typical of real industrial solidification processes such as die casting. These findings can be used to improve future computer models of casting solidification processes for magnesium and for other alloys.

  2. An adaptive reduction algorithm for efficient chemical calculations in global atmospheric chemistry models

    Science.gov (United States)

    Santillana, Mauricio; Le Sager, Philippe; Jacob, Daniel J.; Brenner, Michael P.

    2010-11-01

    We present a computationally efficient adaptive method for calculating the time evolution of the concentrations of chemical species in global 3-D models of atmospheric chemistry. Our strategy consists of partitioning the computational domain into fast and slow regions for each chemical species at every time step. In each grid box, we group the fast species and solve for their concentration in a coupled fashion. Concentrations of the slow species are calculated using a simple semi-implicit formula. Separation of species between fast and slow is done on the fly based on their local production and loss rates. This allows for example to exclude short-lived volatile organic compounds (VOCs) and their oxidation products from chemical calculations in the remote troposphere where their concentrations are negligible, letting the simulation determine the exclusion domain and allowing species to drop out individually from the coupled chemical calculation as their production/loss rates decline. We applied our method to a 1-year simulation of global tropospheric ozone-NO x-VOC-aerosol chemistry using the GEOS-Chem model. Results show a 50% improvement in computational performance for the chemical solver, with no significant added error.

  3. Reduction in Acidity by Chemical and Microbiological Methods and Their Effect on Moslavac Wine Quality

    Directory of Open Access Journals (Sweden)

    Stanka Herjavec

    2003-01-01

    Full Text Available Changes in chemical composition and sensory properties caused by chemical and microbiological methods of deacidification in Moslavac (syn. Furmint wines were investigated. Alcoholic fermentation of Moslavac musts was carried out with two different strains of the yeasts Saccharomyces paradoxus. There were no marked differences in chemical composition among the wines. Compared to the control microbiological deacidification of wines by Oenococcus oeni resulted in a complete decomposition of malic acid, total acidity decrease of 1.55 g/L and pH value increase of 0.14 units. There were no significant differences in volatile acidity, tartaric and citric acid concentrations between the control and malolactically fermented wine. Chemically deacidified wines contained similar total acidity but higher pH values than malolactically fermented wines. Compared to control wines, the tartaric acid concentration decrease of 2.13 g/L and the pH value increase of 0.5 units were determined. The sensory quality of Moslavac wines of high acidity was improved by the applification of deacidification methods. Chemically deacidified wines were assessed as the best whereas the quality of the control wines was judged inferior.

  4. Rapid characterization of chemical compounds in liquid and solid states using thermal desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Huang, Min-Zong; Zhou, Chi-Chang; Liu, De-Lin; Jhang, Siou-Sian; Cheng, Sy-Chyi; Shiea, Jentaie

    2013-10-01

    Rapid characterization of thermally stable chemical compounds in solid or liquid states is achieved through thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS). A feature of this technique is that sampling, desorption, ionization, and mass spectrometric detection are four separate events with respect to time and location. A metal probe was used to sample analytes in their solid or liquid states. The probe was then inserted in a preheated oven to thermally desorb the analytes on the probe. The desorbed analytes were carried by a nitrogen gas stream into an ESI plume, where analyte ions were formed via interactions with charged solvent species generated in the ESI plume. The analyte ions were subsequently detected by a mass analyzer attached to the TD-ESI source. Quantification of acetaminophen in aqueous solutions using TD-ESI/MS was also performed in which a linear response for acetaminophen was obtained between 25 and 500 ppb (R(2) = 0.9978). The standard deviation for a reproducibility test for ten liquid samples was 9.6%. Since sample preparation for TD-ESI/MS is unnecessary, a typical analysis can be completed in less than 10 s. Analytes such as the active ingredients in over-the-counter drugs were rapidly characterized regardless of the different physical properties of said drugs, which included liquid eye drops, viscous cold syrup solution, ointment cream, and a drug tablet. This approach was also used to detect trace chemical compounds in illicit drugs and explosives, in which samples were obtained from the surfaces of a cell phone, piece of luggage made from hard plastic, business card, and wooden desk.

  5. Modeling of Chemical Reactions in Afterburning for the Reduction of N2O

    DEFF Research Database (Denmark)

    Gustavsson, Lennart; Glarborg, Peter; Leckner, Bo

    1996-01-01

    Full scale tests in a 12 MW fluidized bed combustor on reduction of N2O by secondary fuel injection are analyzed in terms a model that involves a detailed reaction mechanism for the gas phase chemistry as well as a description of gas-solid reactions.......Full scale tests in a 12 MW fluidized bed combustor on reduction of N2O by secondary fuel injection are analyzed in terms a model that involves a detailed reaction mechanism for the gas phase chemistry as well as a description of gas-solid reactions....

  6. Rapidly developed squamous cell carcinoma after laser therapy used to treat chemical burn wound: a case report.

    Science.gov (United States)

    Cho, Hyung-Rok; Kwon, Soon-Sung; Chung, Seum; Kie, Jeong-Hae

    2015-02-07

    In chronic wounds, especially burn scars, malignant tumors can arise. However, it is rare for a subacute burn injury to change to a malignant lesion within one month. Moreover, a case of squamous cell carcinoma arising from HeNe laser therapy after a chemical burn has never been reported. In this report, we examine a rare case of squamous cell carcinoma arising from HeNe laser therapy after a chemical burn. Because pathologic investigations were made from the first operation, both early detection of the squamous cell carcinoma and consideration of the HeNe laser therapy as a risk factor for the skin cancer were possible. The cancer was completely removed and reconstruction of the defect was successfully achieved in a timely manner. Although there has as yet been no reported case of squamous cell carcinoma induced by laser therapy, it is important for clinicians to recognize both the possibility of laser-induced cancer and the rapid change of cancer, so they can provide appropriate and timely treatment.

  7. Rapid chemical decontamination of infectious CJD and scrapie particles parallels treatments known to disrupt microbes and biofilms

    Science.gov (United States)

    Botsios, Sotirios; Tittman, Sarah; Manuelidis, Laura

    2015-01-01

    Neurodegenerative human CJD and sheep scrapie are diseases caused by several different transmissible encephalopathy (TSE) agents. These infectious agents provoke innate immune responses in the brain, including late-onset abnormal prion protein (PrP-res) amyloid. Agent particles that lack detectable PrP sequences by deep proteomic analysis are highly infectious. Yet these agents, and their unusual resistance to denaturation, are often evaluated by PrP amyloid disruption. To reexamine the intrinsic resistance of TSE agents to denaturation, a paradigm for less resistant viruses and microbes, we developed a rapid and reproducible high yield agent isolation procedure from cultured cells that minimized PrP amyloid and other cellular proteins. Monotypic neuronal GT1 cells infected with the FU-CJD or 22L scrapie agents do not have complex brain changes that can camouflage infectious particles and prevent their disruption, and there are only 2 reports on infectious titers of any human CJD strain treated with chemical denaturants. Infectious titers of both CJD and scrapie were reduced by >4 logs with Thiourea-urea, a treatment not previously tested. A mere 5 min exposure to 4M GdnHCl at 22°C reduced infectivity by >5 logs. Infectious 22L particles were significantly more sensitive to denaturation than FU-CJD particles. A protocol using sonication with these chemical treatments may effectively decontaminate complicated instruments, such as duodenoscopes that harbor additional virulent microbes and biofilms associated with recent iatrogenic infections. PMID:26556670

  8. Highly Stable and Tunable Chemical Doping of Multilayer WS2 Field Effect Transistor: Reduction in Contact Resistance.

    Science.gov (United States)

    Khalil, Hafiz M W; Khan, Muhammad Farooq; Eom, Jonghwa; Noh, Hwayong

    2015-10-28

    The development of low resistance contacts to 2D transition-metal dichalcogenides (TMDs) is still a big challenge for the future generation field effect transistors (FETs) and optoelectronic devices. Here, we report a chemical doping technique to achieve low contact resistance by keeping the intrinsic properties of few layers WS2. The transfer length method has been used to investigate the effect of chemical doping on contact resistance. After doping, the contact resistance (Rc) of multilayer (ML) WS2 has been reduced to 0.9 kΩ·μm. The significant reduction of the Rc is mainly due to the high electron doping density, thus a reduction in Schottky barrier height, which limits the device performance. The threshold voltage of ML-WS2 FETs confirms a negative shift upon the chemical doping, as further confirmed from the positions of E(1)2g and A1g peaks in Raman spectra. The n-doped samples possess a high drain current of 65 μA/μm, with an on/off ratio of 1.05 × 10(6) and a field effect mobility of 34.7 cm(2)/(V·s) at room temperature. Furthermore, the photoelectric properties of doped WS2 flakes were also measured under deep ultraviolet light. The potential of using LiF doping in contact engineering of TMDs opens new ways to improve the device performance.

  9. Model Reduction in Chemical Engineering : Case studies applied to process analysis, design and operation

    NARCIS (Netherlands)

    Dorneanu, B.

    2011-01-01

    During the last decades, models have become widely used for supporting a broad range of chemical engineering activities, such as product and process design and development, process monitoring and control, real time optimization of plant operation or supply chain management. Although tremendous

  10. Reduction of Allowed Inventory When Chemicals are Located in Close Proximity with Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Y P; Nguyen, S N

    2006-09-27

    The objective of this report is to determine the allowed inventory of chemicals stored in the same bay, building or magazine, i.e., in close proximity, with high explosives (HE) that would, in the event of an accident, result in acceptable risks to colocated workers and the public.

  11. Heterogeneous reduction of uranyl by micas: Crystal chemical and solution controls

    Science.gov (United States)

    Ilton, Eugene S.; Haiduc, Anca; Moses, Carl O.; Heald, Steve M.; Elbert, David C.; Veblen, David R.

    2004-06-01

    This contribution primarily uses X-ray photoelectron spectroscopy (XPS) to better understand mechanisms for coupled sorption-reduction of aqueous U VI by ferrous micas. Additional information was obtained with X-ray absorption spectroscopy (XAS) and transmission electron microscopy (TEM). The research is important because homogeneous reduction of aqueous U VI is sluggish compared to heterogeneous reduction pathways, and micas are important sorbents for uranium in granitic terrains, which have been proposed as potential radionuclide waste disposal sites. Three micas (high, medium and low Fe/Mg biotites), prepared as thin centimeter-sized books, were reacted with U VI solutions that contained 0-25 mM Na + or K +, at pH = 4.5, 5.0, 6.0, and 9.5. All the experiments were performed under argon at one bar. Solid samples were retrieved at timed intervals for up to 20 h. Both mica edge and basal plane orientations were analyzed by XPS. Analyses of peak positions, core satellites, and the 5f valence band indicate that U VI can be reduced by biotite and that heterogeneous reduction depends on the type and concentration of alkali cation in solution, crystallography, and mica composition. We conclude that ferrous micas can reduce U VI on edge sites, but not on exposed basal plane surfaces, and that Na + and K + facilitate and hinder the reaction, respectively. These observations pertain over a broad range of pH. X-Ray absorption near edge spectroscopy (XANES) of annite sections indicates that the interlayer region, as opposed to external basal surfaces, also offers possible sites for heterogeneous reduction of U VI. TEM of annites with high uranium coverage confirmed the presence of interlayer uranium; interestingly, this uranium is concentrated in U-rich nano-scale zones.

  12. Enhanced identification and exploitation of time scales for model reduction in stochastic chemical kinetics.

    Science.gov (United States)

    Gómez-Uribe, Carlos A; Verghese, George C; Tzafriri, Abraham R

    2008-12-28

    Widely different time scales are common in systems of chemical reactions and can be exploited to obtain reduced models applicable to the time scales of interest. These reduced models enable more efficient computation and simplify analysis. A classic example is the irreversible enzymatic reaction, for which separation of time scales in a deterministic mass action kinetics model results in approximate rate laws for the slow dynamics, such as that of Michaelis-Menten. Recently, several methods have been developed for separation of slow and fast time scales in chemical master equation (CME) descriptions of stochastic chemical kinetics, yielding separate reduced CMEs for the slow variables and the fast variables. The paper begins by systematizing the preliminary step of identifying slow and fast variables in a chemical system from a specification of the slow and fast reactions in the system. The authors then present an enhanced time-scale-separation method that can extend the validity and improve the accuracy of existing methods by better accounting for slow reactions when equilibrating the fast subsystem. The resulting method is particularly accurate in systems such as enzymatic and protein interaction networks, where the rates of the slow reactions that modify the slow variables are not a function of the slow variables. The authors apply their methodology to the case of an irreversible enzymatic reaction and show that the resulting improvements in accuracy and validity are analogous to those obtained in the deterministic case by using the total quasi-steady-state approximation rather than the classical Michaelis-Menten. The other main contribution of this paper is to show how mass fluctuation kinetics models, which give approximate evolution equations for the means, variances, and covariances of the concentrations in a chemical system, can feed into time-scale-separation methods at a variety of stages.

  13. ZnO nanorod arrays prepared by chemical bath deposition combined with rapid thermal annealing: structural, photoluminescence and field emission characteristics

    Science.gov (United States)

    Chen, Hung-Wei; Yang, Hsi-Wen; He, Hsin-Min; Lee, Yi-Mu

    2016-01-01

    ZnO nanorod arrays were prepared by low temperature chemical bath deposition (CBD) combined with rapid thermal annealing (RTA) under different ambient conditions. The structure and morphology of the synthesized ZnO have been characterized by field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The obtained ZnO samples are highly crystalline with a hexagonal wurtzite phase and also display well-aligned array structure. A pronounced effect on increased nanorod length was found for the RTA-treated ZnO as compared to the as-grown ZnO. Analysis of XRD indicates that the (0 0 2) feature peak of the as-grown ZnO was shifted towards a lower angle as compared to the peaks of RTA-treated ZnO samples due to the reduction of tensile strain along the c-axis by RTA. Photoluminescence (PL) studies reveal that the ZnO nanorod arrays receiving RTA in an O2 environment have the sharpest UV emission band and greatest intensity ratio of near band-edge emission (NBE) to deep level emission (DLE). Additionally, the effects of RTA on the field emission properties were evaluated. The results demonstrate that RTA an O2 environment can lower the turn-on field and improve the field enhancement factor. The stability of the field emission current was also tested for 4 h.

  14. Features in chemical kinetics. I. Signatures of self-emerging dimensional reduction from a general format of the evolution law

    Science.gov (United States)

    Nicolini, Paolo; Frezzato, Diego

    2013-06-01

    Simplification of chemical kinetics description through dimensional reduction is particularly important to achieve an accurate numerical treatment of complex reacting systems, especially when stiff kinetics are considered and a comprehensive picture of the evolving system is required. To this aim several tools have been proposed in the past decades, such as sensitivity analysis, lumping approaches, and exploitation of time scales separation. In addition, there are methods based on the existence of the so-called slow manifolds, which are hyper-surfaces of lower dimension than the one of the whole phase-space and in whose neighborhood the slow evolution occurs after an initial fast transient. On the other hand, all tools contain to some extent a degree of subjectivity which seems to be irremovable. With reference to macroscopic and spatially homogeneous reacting systems under isothermal conditions, in this work we shall adopt a phenomenological approach to let self-emerge the dimensional reduction from the mathematical structure of the evolution law. By transforming the original system of polynomial differential equations, which describes the chemical evolution, into a universal quadratic format, and making a direct inspection of the high-order time-derivatives of the new dynamic variables, we then formulate a conjecture which leads to the concept of an "attractiveness" region in the phase-space where a well-defined state-dependent rate function ω has the simple evolution dot{ω }= - ω ^2 along any trajectory up to the stationary state. This constitutes, by itself, a drastic dimensional reduction from a system of N-dimensional equations (being N the number of chemical species) to a one-dimensional and universal evolution law for such a characteristic rate. Step-by-step numerical inspections on model kinetic schemes are presented. In the companion paper [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234102 (2013)], 10.1063/1.4809593 this outcome will be naturally

  15. Synthesis of PMA stabilized silver nanoparticles by chemical reduction process under a two-step UV irradiation

    Science.gov (United States)

    Spadaro, D.; Barletta, E.; Barreca, F.; Currò, G.; Neri, F.

    2010-04-01

    Poly(methacrylic acid) (PMA) stabilized silver nanoparticles (Ag NPs), also used in the surface modification of clothing fibers, were fabricated via chemical reduction processes under UV irradiation. To obtain an uniform size distribution it has been designed a new "two-step" process which employs two different UV radiation densities in order to control the kinetics of NPs nucleation. The as produced nanoparticles were characterized by UV-vis absorption spectroscopy and TEM microscopy. The results show the reduction of the Ag ions and the nanoparticles nucleation in the first step. In the second step, the final Ag NPs size distribution is controlled through a quick cross-linking of the PMA that freezes out any further modification. A narrow size distribution with more than 80% NPs smaller than 10 nm and none larger than 25 nm was obtained and the long-term stability (one month) of the colloidal solution was verified.

  16. Concurrent reduction and distillation: an improved technique for the recovery and chemical refinement of the isotopes of cadmium and zinc

    Energy Technology Data Exchange (ETDEWEB)

    Caudill, H.H.; McBride, L.E.; McDaniel, E.W.

    1982-01-01

    The Electromagnetic Isotope Separations Program of the Oak Ridge National Laboratory has been involved in the separation, chemical recovery, and refinement of the stable isotopes of cadmium and zinc since 1946. Traditionally, the chemical refinement procedures for these elements consisted of ion exchange separations using anion exchange resins followed by pH-controlled hydrogen sulfide precipitations. The procedures were quite time-consuming and made it difficult to remove trace quantities of sulfur which interferes in subsequent attempts to prepare rolled metal foils. As demands for /sup 113/Cd and /sup 68/Zn (a precursor for the production of the radiopharmaceutical /sup 67/Ga) increased, it became evident that a quicker, more efficient refinement procedure was needed. Details of an improved method, which employs concurrent hydrogen reduction and distillation in the recovery and refinement of isotopically enriched zinc, are described. Modifications of the procedure suitable for the refinement of cadmium isotopes are also described. 3 figures, 1 table.

  17. Reduction of Cr(VI) to Cr(III) in Artificially-Contaminated Soil using Chemical Reagents

    Science.gov (United States)

    Kostarelos, Konstantinos; Rao, Ennio; Reale, Daniela

    2010-05-01

    The presence of hexavalent chromium (CrVI) in soil is an environmental concern due to its effect on human health. The concern arises from the leaching and the seepage of Cr(VI) from soil to groundwater. A remediation approach that has been studied in the literature is that of reducing the hexavalent chromium to its trivalent form using a chemical reagent, namely ferrous sulfate heptahydrate (FeSO4.7H20). In this study, we compared performance of ferrous sulfate heptahydrate to sodium thiosulfate (Na2S2O3), a less costly reductant. The means of measuring the performance of the reductants is the US EPA's Toxicity Characteristic Leaching Procedure (TCLP), which states that the total chromium release from the soil must be less than 5 ppm. Because this treatment approach is pH sensitive and thus, susceptible to acid rain effects, it was studied with the intention that it be coupled with a stabilization/fixation approach so as to provide a second level of treatment; i.e., it is not intended to be the stand-alone treatment approach. In this study, the reductants were initially used to treat a contaminated, artificial soil and allowed to cure for varying time periods to determine the minimum curing time. Contaminated artificial soil were then prepared using the same percentage of white sand, kaolinite clay and potassium chromate and varying amount of water as a function of the humidity of the specimens in order to illucidate the effect of moisture on the reductant performance. Finally, the reductant (either ferrous sulfate heptahydrate or sodium thiosulfate) was added in varying doses to determine the best ratio Cr/reagent dose. Chromium release from the soil was evaluated with a modified Toxicity Characteristic Leaching Procedure (TCLP) test after allowing the samples to cure. Results indicated that chromium(VI) released from the specimens was less than 5 ppm for the samples treated with either ferrous sulfate heptahydrate (99.9% of reduction) and sodium thiosulfate (98

  18. Chemical and enzymatic reductive activation of acylfulvene to isomeric cytotoxic reactive intermediates

    OpenAIRE

    Pietsch, Kathryn E.; Neels, James F.; Yu, Xiang; Gong, Jiachang; Sturla, Shana J.

    2011-01-01

    Acylfulvenes, a class of semisynthetic analogues of the sesquiterpene natural product illudin S, are cytotoxic towards cancer cells. The minor structural changes between illudin S and AFs translate to an improved therapeutic window in preclinical cell-based assays and xenograft models. AFs are, therefore, unique tools for addressing the chemical and biochemical basis of cytotoxic selectivity. AFs elicit cytotoxic responses by alkylation of biological targets, including DNA. While AFs are capa...

  19. Rapid, Efficient and Versatile Strategies for Functionally Sophisticated Polymers and Nanoparticles: Degradable Polyphosphoesters and Anisotropic Distribution of Chemical Functionalities

    Science.gov (United States)

    Zhang, Shiyi

    conjugate by densely attaching the polyphosphoester block with azide-functionalized Paclitaxel by azide-alkyne Huisgen cycloaddition. This Paclitaxel drug conjugate provides a powerful platform for combinational cancer therapy and bioimaging due to its ultra-high Paclitaxel loading (> 65 wt%), high water solubility (>6.2 mg/mL for PTX) and easy functionalization. Another polyphosphoester-based nanoparticle system has been developed by a programmable process for the rapid and facile preparation of a family of nanoparticles with different surface charges and functionalities. The non-ionic, anionic, cationic and zwitterionic nanoparticles with hydrodynamic diameters between 13 nm to 21 nm and great size uniformity could be rapidly prepared from small molecules in 6 h or 2 days. The anionic and zwitterionic nanoparticles were designed to load silver ions to treat pulmonary infections, while the cationic nanoparticles are being applied to regulate lung injuries by serving as a degradable iNOS inhibitor conjugates. In addition, a direct synthesis of acid-labile polyphosphoramidate by organobase-catalyzed ring-opening polymerization and an improved two-step preparation of polyphosphoester ionomer by acid-assisted cleavage of phosphoramidate bonds on polyphosphoramidate were developed. Polyphosphoramidate and polyphosphoester ionomers may be applied to many applications, due to their unique chemical and physical properties.

  20. Facile preparation of graphene-copper nanoparticle composite by in situ chemical reduction for electrochemical sensing of carbohydrates.

    Science.gov (United States)

    Chen, Qiwen; Zhang, Luyan; Chen, Gang

    2012-01-03

    A novel graphene-copper nanoparticle composite was prepared by the in situ chemical reduction of a mixture containing graphene oxide and copper(II) ions using potassium borohydride as a reductant. It was mixed with paraffin oil and packed into one end of a fused capillary to fabricate microdisc electrodes for sensing carbohydrates. The morphology and structure of the graphene-copper nanoparticle composite were investigated by scanning electron microscopy, X-ray diffraction, and Fourier transform-infrared spectroscopy. The results indicated that copper nanoparticles with an average diameter of 20.8 nm were successfully deposited on graphene nanosheets to form a well interconnected hybrid network. The analytical performance of these unique graphene-copper nanoparticle composite paste electrodes was demonstrated by sensing five carbohydrates in combination with cyclic voltammetry and capillary electrophoresis (CE). The advantages of the composite detectors include higher sensitivity, satisfactory stability, surface renewability, bulk modification, and low expense of fabrication. They should find applications in microchip CE, flowing-injection analysis, and other microfluidic analysis systems. © 2011 American Chemical Society

  1. Act on the Registration and Evaluation of Chemicals (K-REACH and replacement, reduction or refinement best practices

    Directory of Open Access Journals (Sweden)

    Soojin Ha

    2016-12-01

    Full Text Available Objectives Korea’s Act on the Registration and Evaluation of Chemicals (K-REACH was enacted for the protection of human health and the environment in 2015. Considering that about 2000 new substances are introduced annually across the globe, the extent of animal testing requirement could be overwhelming unless regulators and companies work proactively to institute and enforce global best practices to replace, reduce or refine animal use. In this review, the way to reduce the animal use for K-REACH is discussed. Methods Background of the enforcement of the K-REACH and its details was reviewed along with the papers and regulatory documents regarding the limitation of animal experiments and its alternatives in order to discuss the regulatory adoption of alternative tests. Results Depending on the tonnage of the chemical used, the data required ranges from acute and other short-term studies for a single exposure route to testing via multiple exposure routes and costly, longer-term studies such as a full two-generation reproducibility toxicity. The European Registration, Evaluation, Authorization and Restriction of Chemicals regulation provides for mandatory sharing of vertebrate test data to avoid unnecessary duplication of animal use and test costs, and obligation to revise data requirements and test guidelines “as soon as possible” after relevant, validated replacement, reduction or refinement (3R methods become available. Furthermore, the Organization for Economic Cooperation and Development actively accepts alternative animal tests and 3R to chemical toxicity tests. Conclusions Alternative tests which are more ethical and efficient than animal experiments should be widely used to assess the toxicity of chemicals for K-REACH registration. The relevant regulatory agencies will have to make efforts to actively adopt and uptake new alternative tests and 3R to K-REACH.

  2. Plasma for electrification of chemical industry: a case study on CO2 reduction

    Science.gov (United States)

    van Rooij, G. J.; Akse, H. N.; Bongers, W. A.; van de Sanden, M. C. M.

    2018-01-01

    Significant growth of the share of (intermittent) renewable power in the chemical industry is imperative to meet increasingly stricter limits on CO2 exhaust that are being implemented within Europe. This paper aims to evaluate the potential of a plasma process that converts input CO2 into a pure stream of CO to aid in renewable energy penetration in this sector. A realistic process design is constructed to serve as a basis for an economical analysis. The manufacturing cost price of CO is estimated at 1.2 kUS ton–1 CO. A sensitivity analysis shows that separation is the dominant cost factor, so that improving conversion is currently more effective to lower the price than e.g. energy efficiency.

  3. Rapid identification of regulated organic chemical compounds in toys using ambient ionization and a miniature mass spectrometry system.

    Science.gov (United States)

    Guo, Xiangyu; Bai, Hua; Lv, Yueguang; Xi, Guangcheng; Li, Junfang; Ma, Xiaoxiao; Ren, Yue; Ouyang, Zheng; Ma, Qiang

    2018-04-01

    Rapid, on-site analysis was achieved through significantly simplified operation procedures for a wide variety of toy samples (crayon, temporary tattoo sticker, finger paint, modeling clay, and bubble solution) using a miniature mass spectrometry system with ambient ionization capability. The labor-intensive analytical protocols involving sample workup and chemical separation, traditionally required for MS-based analysis, were replaced by direct sampling analysis using ambient ionization methods. A Mini β ion trap miniature mass spectrometer was coupled with versatile ambient ionization methods, e.g. paper spray, extraction spray and slug-flow microextraction nanoESI for direct identification of prohibited colorants, carcinogenic primary aromatic amines, allergenic fragrances, preservatives and plasticizers from raw toy samples. The use of paper substrates coated with Co 3 O 4 nanoparticles allowed a great increase in sensitivity for paper spray. Limits of detection as low as 5μgkg -1 were obtained for target analytes. The methods being developed based on the integration of ambient ionization with miniature mass spectrometer represent alternatives to current in-lab MS analysis operation, and would enable fast, outside-the-lab screening of toy products to ensure children's safety and health. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. SiC/Si heterojunction diodes fabricated by self-selective and by blanket rapid thermal chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Yih, P.H.; Li, J.P.; Steckl, A.J. (Univ. of Cincinnati, OH (United States). Dept. of Electrical and Computer Engineering)

    1994-03-01

    SiC/Si heterojunction diodes have been fabricated by two different rapid thermal chemical vapor deposition (RTCVD) processes: a localized self-selective growth and blanket growth. The self-selective growth of crystalline cubic ([beta]) SiC was obtained by propane carbonization of the Si substrate in regions unprotected by an SiO[sub 2] layer, producing planar diodes. Mesa diodes were fabricated using the blanket growth of polycrystalline [beta]-SiC produced by the decomposition of methylsilane (CH[sub 3]SiH[sub 3]). The SiC/Si heterojunction diodes show good rectifying properties for both device structures. Reverse breakdown voltage of 50 V was obtained with the self-selective SiC/Si diode. The mesa diodes exhibited even higher breakdown voltages (V[sub br]) of 150 V and excellent ideality factors of 1.06 at 25 C. The high V[sub br] and good forward rectifying characteristics indicate that the SiC/Si heterojunction diode represents a promising approach for the fabrication of wide-gap emitter SiC/Si heterojunction bipolar transistors.

  5. Towards rapid nanoscale chemical analysis using tip-enhanced Raman spectroscopy with Ag-coated dielectric tips.

    Science.gov (United States)

    Yeo, Boon-Siang; Schmid, Thomas; Zhang, Weihua; Zenobi, Renato

    2007-04-01

    The influence of dielectric substrates on the Raman scattering activities of Ag overlayers has been investigated. Materials with low refractive indices, such as SiO(2), SiO(x) and AlF(3), were found to provide suitable supporting platforms for Ag films to give strong surface-enhanced Raman scattering for dye molecules when illuminated at 488 nm. This finding was then extended to tip-enhanced Raman scattering (TERS). Huge enhancements of 70-80x, corresponding to net enhancements of >10(4), were observed for brilliant cresyl blue test analyte when Ag-coated tips made from or precoated with low refractive index materials were applied. The yield of fabricated tips that significantly enhance the Raman signals was found to be close to 100%. These findings provide crucial steps towards the use of TERS as a robust technique for rapid chemical imaging with nanometer spatial resolution. Figure Silver-coated dielectric tips for tip-enhanced Raman scattering (TERS) are capable of more than 10,000-fold enhancement.

  6. Influence of Chemical and Physical Properties of Activated Carbon Powders on Oxygen Reduction and Microbial Fuel Cell Performance

    KAUST Repository

    Watson, Valerie J.

    2013-06-03

    Commercially available activated carbon (AC) powders made from different precursor materials (coal, peat, coconut shell, hardwood, and phenolic resin) were electrochemically evaluated as oxygen reduction catalysts and tested as cathode catalysts in microbial fuel cells (MFCs). AC powders were characterized in terms of surface chemistry and porosity, and their kinetic activities were compared to carbon black and platinum catalysts in rotating disk electrode (RDE) tests. Cathodes using the coal-derived AC had the highest power densities in MFCs (1620 ± 10 mW m-2). Peat-based AC performed similarly in MFC tests (1610 ± 100 mW m-2) and had the best catalyst performance, with an onset potential of Eonset = 0.17 V, and n = 3.6 electrons used for oxygen reduction. Hardwood based AC had the highest number of acidic surface functional groups and the poorest performance in MFC and catalysis tests (630 ± 10 mW m-2, Eonset = -0.01 V, n = 2.1). There was an inverse relationship between onset potential and quantity of strong acid (pKa < 8) functional groups, and a larger fraction of microporosity was negatively correlated with power production in MFCs. Surface area alone was a poor predictor of catalyst performance, and a high quantity of acidic surface functional groups was determined to be detrimental to oxygen reduction and cathode performance. © 2013 American Chemical Society.

  7. IN-SITU CHEMICAL STABILIZATION OF METALS AND RADIONUCLIDES THROUGH ENHANCED ANAEROBIC REDUCTIVE PRECIPITATION

    Energy Technology Data Exchange (ETDEWEB)

    Christopher C. Lutes; Angela Frizzell, PG; Todd A. Thornton; James M. Harrington

    2003-08-01

    The objective of this NETL sponsored bench-scale study was to demonstrate the efficacy of enhanced anaerobic reductive precipitation (EARP) technology for precipitating uranium using samples from contaminated groundwater at the Fernald Closure Project (FCP) in Cincinnati, Ohio. EARP enhances the natural biological reactions in the groundwater through addition of food grade substrates (typically molasses) to drive the oxidative-reductive potential of the groundwater to a lower, more reduced state, thereby precipitating uranium from solution. In order for this in-situ technology to be successful in the long term, the precipitated uranium must not be re-dissolved at an unacceptable rate once groundwater geochemical conditions return to their pretreatment, aerobic state. The approach for this study is based on the premise that redissolution of precipitated uranium will be slowed by several mechanisms including the presence of iron sulfide precipitates and coatings, and sorption onto fresh iron oxides. A bench-scale study of the technology was performed using columns packed with site soil and subjected to a continuous flow of uranium-contaminated site groundwater (476 {micro}g/L). The ''treated'' column received a steady stream of dilute food grade molasses injected into the contaminated influent. Upon attainment of a consistently reducing environment and demonstrated removal of uranium, an iron sulfate amendment was added along with the molasses in the influent solution. After a month long period of iron addition, the treatments were halted, and uncontaminated, aerobic, unamended water was introduced to the treated column to assess rebound of uranium concentrations. In the first two months of treatment, the uranium concentration in the treated column decreased to the clean-up level (30 {micro}g/L) or below, and remained there for the remainder of the treatment period. A brief period of resolubilization of uranium was observed as the treated column

  8. Photomask defect tracing, analysis, and reduction with chemically amplified resist process

    Science.gov (United States)

    Lin, Cheng-ming; Lai, Rick; Huang, W. H.; Wang, B. C.; Chen, C. Y.; Kung, C. H.; Yoo, Chue-San; Chen, Jieh-Jang; Lee, Sheng-Cha

    2003-08-01

    The features of optical proximity correction are becoming very aggressive as production technology migrates into 90nm/130 nm regime. The complicated optical proximity correction (OPC) patterns often result in un-repairable defects, a major yield loss mechanisms in a mask production line. Defect control is increasingly important. A methodology for identifying defect sources and reduction is demonstrated in this paper. The mechanisms and causes of defect formation could be determined with corresponding process step on the strength of sequence inspections. The cause of half-etched opaque defect on negative CAR process was found from PR fragment contamination of e-beam exposure step. After clean-up of e-beam chamber, yield was increased over 20%. Big pinhole defect and contact of AttPSM positive process was found on ADI step. The possible cause was poor CAR adhesion. These two type defects were decreased by modification of developing recipe, special on rinse step. Design experiment with Taguchi method was used to optimize the interactive recipe of plasma descum and rinse step on developing step of implanted layer. Average defect density was decreased from 0.99 to 0.27, and percentage of zero defect rate has been increased from 29.5 to 63.3%.

  9. Synthesis of reduced graphene oxide (rGO) via chemical reduction

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Alpana, E-mail: alpanarangoli@gmail.com; Rangra, V. S. [Department of Physics, Himachal Pradesh University, Shimla (India); Kumar, Sunil [Department of Applied Sciences, Sri Sai University, Palampur (India)

    2015-05-15

    Natural flake Graphite was used as the starting material for the graphene synthesis. In the first step flake graphite was treated with oxidizing agents under vigorous conditions to obtain graphite oxide. Layered graphite oxide decorated with oxygen has large inter-layer distance leading easy exfoliation into single sheets by ultrasonication giving graphene oxide. In the last step exfoliated graphene oxide sheets were reduced slowly with the help of reducing agent to obtain fine powder which is labeled as reduced graphene oxide (rGO). This rGO was further characterized by X-Ray Diffraction (XRD), Scanning Tunneling Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy techniques. XRD pattern shows peaks corresponding to (002) graphitic lattice planes indicating the formation of network of sp{sup 2} like carbon structure. SEM images show the ultrathin, wrinkled, paper-like morphology of graphene sheets. IR study shows that the graphite has been oxidized to graphite oxide with the presence of various absorption bands confirming the presence of oxidizing groups. The FTIR spectrum of rGO shows no sharp peaks confirming the efficient reduction of rGO. The Raman spectrum shows disorder in the graphene sheets.

  10. Reduction of Contaminants (Physical, Chemical, and Microbial) in Domestic Wastewater through Hybrid Constructed Wetland.

    Science.gov (United States)

    Sehar, Shama; Aamir, Rabia; Naz, Iffat; Ali, Naeem; Ahmed, Safia

    2013-01-01

    The current research was focused mainly on the designing and construction of efficient laboratory scale hybrid constructed wetland (HCW) for the treatment of domestic wastewater. Parameters like COD, BOD5, PO4, SO4, NO3, NO2, and pathogenic indicator microbes were monitored after hydraulic retention time (HRT) of 4, 8, 12, 16, and 20 days. Treatment efficiency of HCW kept on increasing with the increase in hydraulic retention time. Maximum efficiency of HCW was observed with a 20-day HRT, that is, 97.55, 97.5, 89.35, 80.75, 96.04, 91.52, and 98.6% reduction from the zero time value for COD, BOD5, PO4, SO4, NO3, NO2, and fecal coliforms, respectively. After 20 days' time, the treated water was free of almost all nutrients and microbial pollutants. Hence, increasing hydraulic retention time was found to ameliorate the operational competence of HCW. Thus HCW can serve as a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries.

  11. Reduction of Contaminants (Physical, Chemical, and Microbial) in Domestic Wastewater through Hybrid Constructed Wetland

    Science.gov (United States)

    Sehar, Shama; Aamir, Rabia; Naz, Iffat; Ali, Naeem; Ahmed, Safia

    2013-01-01

    The current research was focused mainly on the designing and construction of efficient laboratory scale hybrid constructed wetland (HCW) for the treatment of domestic wastewater. Parameters like COD, BOD5, PO4, SO4, NO3, NO2, and pathogenic indicator microbes were monitored after hydraulic retention time (HRT) of 4, 8, 12, 16, and 20 days. Treatment efficiency of HCW kept on increasing with the increase in hydraulic retention time. Maximum efficiency of HCW was observed with a 20-day HRT, that is, 97.55, 97.5, 89.35, 80.75, 96.04, 91.52, and 98.6% reduction from the zero time value for COD, BOD5, PO4, SO4, NO3, NO2, and fecal coliforms, respectively. After 20 days' time, the treated water was free of almost all nutrients and microbial pollutants. Hence, increasing hydraulic retention time was found to ameliorate the operational competence of HCW. Thus HCW can serve as a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries. PMID:23724336

  12. Catalytic CO2 reduction to valuable chemicals using NiFe-based nanoclusters: a first-principles theoretical evaluation.

    Science.gov (United States)

    Gong, Li; Chen, Jie-Jie; Mu, Yang

    2017-10-25

    Converting CO2 into valuable chemicals and fuels is one of the most practical routes for reducing CO2 emissions while fossil fuels continue to dominate the energy sector. Noble-metal-free NiFe bimetal nanoparticles have shown good catalytic activity in CO2 conversion. Herein we theoretically evaluated the catalytic performance and possible mechanisms of NiFe-based nanoclusters for hydrogenating CO2 to form formic acid and CO through bicarbonate by using a periodic and self-consistent density functional theory (DFT) simulation. The theoretical results illustrated that NiFe nanoclusters could have good catalytic activity and selectivity for HCO3- reduction to formic acid and the possible pathway is that HCO3- preferred to react with adsorbed H atoms of H2 on NiFe alloy nanoclusters through the carbon atom site. Moreover, the NiFe alloy nanoclusters with the Fe atom exposed on the surface of the Ni cluster showed better performance with a lower energy barrier compared to that with Fe doped in the corner of the Ni cluster. However, the generation of CO from HCO3- reduction was shown to be neither thermodynamically nor kinetically favorable on NiFe alloy nanoclusters. Additionally, the simulation results also suggested that it was thermodynamically unfavorable for further hydrogenated reduction of formic acid to formaldehyde on NiFe alloy nanoclusters themselves as well as supported on graphene. In summary, a molecular-level insight of CO2 reduction to valuable products on NiFe nanoclusters is offered in this study, which may provide some useful information for guiding the design of NiFe-based catalytic materials for efficient CO2 conversion to useful fuels.

  13. Rapid Biosynthesis of Silver Nanoparticles Based on Flocculation and Reduction of an Exopolysaccharide from Arthrobacter sp. B4: Its Antimicrobial Activity and Phytotoxicity

    Directory of Open Access Journals (Sweden)

    Li Yumei

    2017-01-01

    Full Text Available Silver nanoparticles (AgNPs were rapidly synthesized using an exopolysaccharide from Arthrobacter sp. B4 (B4-EPS. The optimum condition for AgNPs synthesis was under the concentration of 5 g/L B4-EPS and 1 mM AgNO3 at 80°C between pH 7.0 and 8.0. The resulting AgNPs displayed a face-centred-cubic structure with the size range from 9 nm to 72 nm. Further analysis showed that flocculation and reduction of B4-EPS played a pivotal role in the formation of AgNPs. Furthermore, these nanoparticles exhibited great stability, excellent antimicrobial activity, and low phytotoxicity. The aforementioned data provide a feasible and efficient approach for green synthesis of AgNPs using microbial polysaccharides with flocculation and reduction activity, which will be promising in medical filed.

  14. Determination of decimal reduction time (D value of chemical agents used in hospitals for disinfection purposes

    Directory of Open Access Journals (Sweden)

    da S Martins Alzira M

    2003-10-01

    Full Text Available Abstract Background Prior to the selection of disinfectants for low, intermediate and high (sterilizing levels, the decimal reduction time, D-value, for the most common and persistent bacteria identified at a health care facility should be determined. Methods The D-value was determined by inoculating 100 mL of disinfecting solution with 1 mL of a bacterial suspension (104 – 105 CFU/mL for vegetative and spore forms. At regular intervals, 1 mL aliquots of this mixture were transferred to 8 mL of growth media containing a neutralizing agent, and incubated at optimal conditions for the microorganism. Results The highest D-values for various bacteria were determined for the following solutions: (i 0.1% sodium dichloroisocyanurate (pH 7.0 – E. coli and A. calcoaceticus (D = 5.9 min; (ii sodium hypochlorite (pH 7.0 at 0.025% for B. stearothermophilus (D = 24 min, E. coli and E. cloacae (D = 7.5 min; at 0.05% for B. stearothermophilus (D = 9.4 min and E. coli (D = 6.1 min and 0.1% for B. stearothermophilus (D = 3.5 min and B. subtilis (D = 3.2 min; (iii 2.0% glutaraldehyde (pH 7.4 – B. stearothermophilus, B. subtilis (D = 25 min and E. coli (D = 7.1 min; (iv 0.5% formaldehyde (pH 6.5 – B. subtilis (D = 11.8 min, B. stearothermophilus (D = 10.9 min and A. calcoaceticus (D = 5.2 min; (v 2.0% chlorhexidine (pH 6.2 – B. stearothermophilus (D = 9.1 min, and at 0.4% for E. cloacae (D = 8.3 min; (vi 1.0% Minncare® (peracetic acid and hydrogen peroxide, pH 2.3 – B. stearothermophilus (D = 9.1 min and E. coli (D = 6.7 min. Conclusions The suspension studies were an indication of the disinfectant efficacy on a surface. The data in this study reflect the formulations used and may vary from product to product. The expected effectiveness from the studied formulations showed that the tested agents can be recommended for surface disinfection as stated in present guidelines and emphasizes the importance and need to develop routine and novel programs to

  15. Chemical and Microbial Characterization of North Slope Viscous Oils to Assess Viscosity Reduction and Enhanced Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Shirish Patil; Abhijit Dandekar; Mary Beth Leigh

    2008-12-31

    A large proportion of Alaska North Slope (ANS) oil exists in the form of viscous deposits, which cannot be produced entirely using conventional methods. Microbially enhanced oil recovery (MEOR) is a promising approach for improving oil recovery for viscous deposits. MEOR can be achieved using either ex situ approaches such as flooding with microbial biosurfactants or injection of exogenous surfactant-producing microbes into the reservoir, or by in situ approaches such as biostimulation of indigenous surfactant-producing microbes in the oil. Experimental work was performed to analyze the potential application of MEOR to the ANS oil fields through both ex situ and in situ approaches. A microbial formulation containing a known biosurfactant-producing strain of Bacillus licheniformis was developed in order to simulate MEOR. Coreflooding experiments were performed to simulate MEOR and quantify the incremental oil recovery. Properties like viscosity, density, and chemical composition of oil were monitored to propose a mechanism for oil recovery. The microbial formulation significantly increased incremental oil recovery, and molecular biological analyses indicated that the strain survived during the shut-in period. The indigenous microflora of ANS heavy oils was investigated to characterize the microbial communities and test for surfactant producers that are potentially useful for biostimulation. Bacteria that reduce the surface tension of aqueous media were isolated from one of the five ANS oils (Milne Point) and from rock oiled by the Exxon Valdez oil spill (EVOS), and may prove valuable for ex situ MEOR strategies. The total bacterial community composition of the six different oils was evaluated using molecular genetic tools, which revealed that each oil tested possessed a unique fingerprint indicating a diverse bacterial community and varied assemblages. Collectively we have demonstrated that there is potential for in situ and ex situ MEOR of ANS oils. Future work

  16. Chemical Stability of Conductive Ceramic Anodes in LiCl–Li2O Molten Salt for Electrolytic Reduction in Pyroprocessing

    Directory of Open Access Journals (Sweden)

    Sung-Wook Kim

    2016-08-01

    Full Text Available Conductive ceramics are being developed to replace current Pt anodes in the electrolytic reduction of spent oxide fuels in pyroprocessing. While several conductive ceramics have shown promising electrochemical properties in small-scale experiments, their long-term stabilities have not yet been investigated. In this study, the chemical stability of conductive La0.33Sr0.67MnO3 in LiCl–Li2O molten salt at 650°C was investigated to examine its feasibility as an anode material. Dissolution of Sr at the anode surface led to structural collapse, thereby indicating that the lifetime of the La0.33Sr0.67MnO3 anode is limited. The dissolution rate of Sr is likely to be influenced by the local environment around Sr in the perovskite framework.

  17. Efficiency of some soil bacteria for chemical oxygen demand reduction of synthetic chlorsulfuron solutions under agiated culture conditions.

    Science.gov (United States)

    Erguven, G O; Yildirim, N

    2016-05-30

    This study searches the efficiency of certain soil bacteria on chemical oxygen demand (COD) reduction of synthetic chlorsulfuron solutions under agitated culture conditions. It also aims to determine the turbidity of liquid culture medium with chlorsulfuron during bacterial incubation for 120 hours. As a result the highest and lowest COD removal efficiency of bacteria was determined for Bacillus simplex as 94% and for Micrococcus luteus as 70%, respectively at the end of the 96th hour. It was found that COD removal efficiency showed certain differences depend on the bacterial species. It was also observed that B. simplex had the highest COD removal efficiency and it was a suitable bacterium species for bioremediation of a chlorsulfuron contaminated soils.

  18. Silver nanoparticles prepared by chemical reduction-protection method, and their application in electrically conductive silver nanopaste

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jianguo, E-mail: ljg712@yahoo.com.c [Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Li Xiangyou; Zeng Xiaoyan [Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2010-04-02

    Ag nanoparticles were prepared in a water-phase system with a mixture of silver-ammonia complex, sodium borohydride, and lauric acid according to molar feed ratio of approximately 6:3:1. The mechanism of preparation and separation by chemical reduction-protection method was explored. The as-synthesized Ag nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis spectroscopy, respectively. It was found that the size of high purity Ag particles was ranging from 30 to 50 nm with slight agglomeration. In addition, the as-synthesized wet Ag nanoparticles were dispersed stably in organic vehicle to formulate electrically conductive nanopaste. Upon direct-written and sintered, the array pattern of the nanopaste with the resolution of about 30 {mu}m was achieved with the electrical resistivity in the order of magnitude of 10{sup -5} {Omega} cm.

  19. Adherent and Conformal Zn(S,O,OH) Thin Films by Rapid Chemical Bath Deposition with Hexamethylenetetramine Additive.

    Science.gov (United States)

    Opasanont, Borirak; Van, Khoa T; Kuba, Austin G; Choudhury, Kaushik Roy; Baxter, Jason B

    2015-06-03

    ZnS is a wide band gap semiconductor whose many applications, such as photovoltaic buffer layers, require uniform and continuous films down to several nanometers thick. Chemical bath deposition (CBD) is a simple, low-cost, and scalable technique to deposit such inorganic films. However, previous attempts at CBD of ZnS have often resulted in nodular noncontinuous films, slow growth rates at low pH, and high ratio of oxygen impurities at high pH. In this work, ZnS thin films were grown by adding hexamethylenetetramine (HMTA) to a conventional recipe that uses zinc sulfate, nitrilotriacetic acid trisodium salt, and thioacetamide. Dynamic bath characterization showed that HMTA helps the bath to maintain near-neutral pH and also acts as a catalyst, which leads to fast nucleation and deposition rates, continuous films, and less oxygen impurities in the films. Films deposited on glass from HMTA-containing bath were uniform, continuous, and 90 nm thick after 1 h, as opposed to films grown without HMTA that were ∼3 times thinner and more nodular. On Cu2(Zn,Sn)Se4, films grown with HMTA were continuous within 10 min. The films have comparatively few oxygen impurities, with S/(S+O) atomic ratio of 88%, and high optical transmission of 98% at 360 nm. The Zn(S,O,OH) films exhibit excellent adhesion to glass and high resistivity, which make them ideal nucleation layers for other metal sulfides. Their promise as a nucleation layer was demonstrated with the deposition of thin, continuous Sb2S3 overlayers. This novel HMTA chemistry enables rapid deposition of Zn(S,O,OH) thin films to serve as a nucleation layer, a photovoltaic buffer layer, or an extremely thin continuous coating for thin film applications. HMTA may also be applied in a similar manner for solution deposition of other metal chalcogenide and oxide thin films with superior properties.

  20. Rapid isolation of a facultative anaerobic electrochemically active bacterium capable of oxidizing acetate for electrogenesis and azo dyes reduction.

    Science.gov (United States)

    Shen, Nan; Yuan, Shi-Jie; Wu, Chao; Cheng, Yuan-Yuan; Song, Xiang-Ning; Li, Wen-Wei; Tong, Zhong-Hua; Yu, Han-Qing

    2014-05-01

    In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO3 nanoclusters. These strains caused color change of WO3 from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source.

  1. Enhanced chemical oxygen demand removal and flux reduction in pulp and paper wastewater treatment using laccase-polymerized membrane filtration.

    Science.gov (United States)

    Ko, Chun-Han; Fan, Chihhao

    2010-09-15

    The purpose of this present study is to investigate the removal efficiency of chemical oxygen demand (COD) from pulp and paper wastewater using laccase-polymerized membrane filtration process. The membranes with molecular weight cut-off (MWCO) of 5000 and 10,000, 30,000 and 54,000 were used in a cross-flow module to treat the pulp and paper wastewater containing high phenolic constituents and COD. With 2.98 IU/L of activated laccase applied at room temperature for 180 min, the contaminants in raw wastewater and second effluent were polymerized to form larger molecules with average molecular weight of 1300 and 900 Da (Dalton), respectively. With laccase polymerization prior to filtration, over 60% removals of COD by the four investigated membranes were observed, compared with low COD removal without laccase polymerization. Moreover, the addition of laccase resulted in 4-14% reduction of membrane permeability during the first 180 min filtration operation due to gel layer formation by the polymerization. No further flux decline was observed afterwards indicating the steady state was reached and the membranes could be used to remove the polymerized pollutants without significant fouling. The maximum apparent resistance occurrence for raw wastewater treated with laccase also supported the effectiveness for COD removal with laccase polymerization before membrane filtration. Additionally, pretreatment by inactivated laccase only caused further flux reduction without additional removal of COD. Copyright 2010 Elsevier B.V. All rights reserved.

  2. In situ chemical reductive growth of platinum nanoparticles on indium tin oxide surfaces and their electrochemical applications.

    Science.gov (United States)

    Chang, Gang; Oyama, Munetaka; Hirao, Kazuyuki

    2006-02-02

    Platinum nanoparticles directly attached to indium tin oxide (PtNP/ITO) were successfully fabricated by using an in situ chemical reductive growth method. In this method, PtNPs could be grown on the ITO surface via the one-step immersion into the growth solution containing PtCl4(2-) and ascorbic acid. The attached and grown PtNPs were spherical having an agglomerated nanostructure composed of small nanoclusters. From the morphological changes depending on the growth time, which were observed with an FE-SEM, PtNPs were found to be grown via the progressive nucleation mechanism. As the characteristics of the PtNP/ITO were those of a working electrode, it was found that the charge transfer resisivity was significantly lowered due to the grown PtNPs. Hence, for a typical redox system of [Fe(CN)6]3-/[Fe(CN)6]4-, the PtNP/ITO electrode exhibited the electrochemical responses similar to those of the bulk Pt electrode. Furthermore, it was clarified that the PtNP/ITO electrode had significant electrocatalytic properties for the oxygen reduction and methanol oxidation. The present PtNPs that had the agglomerated nanostructure may be promising for a new type of electrode material.

  3. Mindfulness-based Stress Reduction (MBSR) and Its Effects on Psychoimmunological Factors of Chemically Pulmonary Injured Veterans.

    Science.gov (United States)

    Arefnasab, Zahra; Babamahmoodi, Abdolreza; Babamahmoodi, Farhang; Noorbala, Ahmad Ali; Alipour, Ahmad; Panahi, Yunes; Shams, Jamal; Riazi Rad, Farhad; Khaze, Vahid; Ghanei, Mostafa

    2016-12-01

    Mindfulness-based Stress Reduction (MBSR) is a treatment program for relieving stress and coping with chronic illnesses. In recent three decades, studies have shown that MBSR has a positive effect on physical and psychological dimensions of chronic illnesses. Chemically pulmonary injured veterans have chronic pulmonary and psychological problems due to mustard gas exposure and complications of Iran-Iraq war. These stresses have negative effects on their general health and immune system. To the best of our knowledge, this is the first study conducted on psychoneuroimmunology and MBSR in these patients. Forty male pulmonary injured veterans were randomly divided in two groups with 20 participants (MBSR and wait-list control). Then MBSR group received 8 weekly sessions of intervention. We tested mental health based on general health questionnaire (GHQ)-28 questionnaire, health-related quality of life (based on St. George respiratory questionnaire (SGRQ) ) and immunity in MBSR groups; before and after intervention "mixed factorial analyses of variance" test was used for analyzing data fpr each dependent variable and appropriate t-tests were done in The necessary condition. Results showed that mental health and health- related quality of life, in MBSR group compared to wait-list control improved [F (1,38)=26.46, pMBSR may be a new treatment approach for improving immunity and overall health in chemically pulmonary injured veterans.

  4. Rapid reduction of malaria following introduction of vector control interventions in Tororo District, Uganda: a descriptive study.

    Science.gov (United States)

    Oguttu, David W; Matovu, Joseph K B; Okumu, David C; Ario, Alex R; Okullo, Allen E; Opigo, Jimmy; Nankabirwa, Victoria

    2017-05-30

    In 2012, Tororo District had the highest malaria burden in Uganda with community Plasmodium prevalence of 48%. To control malaria in the district, the Ministry of Health introduced universal distribution of long lasting insecticide-treated nets (LLINs) in 2013 and added indoor residual spraying (IRS) in 2014. This study assessed malaria incidence, test positivity rates and outpatient (OPD) attendance due to malaria before and after vector control interventions. This study was based on analysis of Health Management Information System (HMIS) secondary malaria surveillance data of 2,727,850 patient records in OPD registers of 61 health facilities from 2012 to 2015. The analysis estimated monthly malaria incidence for the entire population and also separately for introduction of vector control interventions; determined laboratory test positivity rates and annual percentage of malaria cases in OPD. Chi square for trends was used to analyse annual change in malaria incidence and logistic regression for monthly reduction. Following universal LLINs coverage, the annual mean monthly malaria incidence fell from 95 cases in 2013 to 76 cases per 1000 in 2014 with no significant monthly reduction (OR = 0.99, 95% CI 0.96-1.01, P = 0.37). Among children malaria incidence reduced from 130 to 100 cases per 1000 (OR = 0.98, 95% CI 0.97-1.00, P = 0.08) when LLINs were used alone in 2014, but declined to 45 per 1000 in 2015 when IRS was combined with LLINs (OR = 0.94, 95% CI 0.91-0.996, P malaria incidence reduced from 59 to 52 cases per 1000 (OR = 0.99, 95% CI 0.97-1.02, P = 0.8) when LLINs were used alone in 2014, but reduced significantly to 25 per 1000 in 2015 (OR = 0.91, 95% CI 0.88-0.94, P Malaria test positivity rate reduced from 57% in 2013 to 30% (Chi = 15, P malaria incidence was observed in Tororo District following the introduction of IRS in addition to LLINs. There was no significant reduction in malaria incidence following universal distribution

  5. Rapid reduction of MDCK cell cholesterol by methyl-beta-cyclodextrin alters steady state transepithelial electrical resistance.

    Science.gov (United States)

    Francis, S A; Kelly, J M; McCormack, J; Rogers, R A; Lai, J; Schneeberger, E E; Lynch, R D

    1999-07-01

    The role of plasma membrane lipids in regulating the passage of ions and other solutes through the paracellular pathway remains controversial. In this study we explore the contribution of cholesterol (CH) in maintaining the barrier function of an epithelial cell line using the CH-solubilizing agent methyl beta-cyclodextrin (MBCD) to stimulate CH efflux. Inclusion of 20 mM MBCD in both apical and basolateral media reduced CH levels by 70-80% with no significant effect on cell viability. Most of that decrease occurred during the first 30 min of incubation. Recovery of CH content to initial values was nearly complete 22 h after removal of MBCD. Within 30 min of adding MBCD to the culture medium, transepithelial electrical resistance (TER) increased, reaching maximum values 30-40% above controls. This early rise in TER occurred when MBCD was added to either side of the monolayer. The later rapid decline in TER was observed only when MBCD bathed the basolateral surface from which, coincidentally, CH efflux was most rapid. Freeze fracture replicas and transmission electron microscopy of monolayers exposed to MBCD for only 30 min revealed no increase in either the average tight junction (TJ) strand number or the dimensions of the lateral intercellular space. There was a statistically significant increase in the number of TJ particles associated with the E fracture face at this time. This raises the interesting possibility that during CH efflux there is a change in the interaction between TJ particles and underlying cytoskeletal elements. There was no change in staining for occludin and ZO-1. After exposing the basolateral surface to MBCD for 2 h, TER fell below control levels. The accompanying increase in mannitol flux suggests strongly that the decrease in TER resulted from an increase in the permeability of the paracellular and not the transcellular pathway. A decrease in immuno-staining for occludin and ZO-1 at TJs, a striking accumulation of actin at tri

  6. A simple Cr(VI)–S(IV)–O{sub 2} system for rapid and simultaneous reduction of Cr(VI) and oxidative degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Yanan; Yang, Shaojie [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079 (China); Zhou, Danna, E-mail: zdncug@163.com [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Wu, Feng [Department of Environmental Science, Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, 430079 (China)

    2016-04-15

    Highlights: • Rapid and simultaneous reduction of Cr(VI) and degradation of organic pollutants occur. • Oxysulfur radicals generated in Cr(VI)–S(IV)–O{sub 2} system oxidize the organic pollutants. • Acidic pH facilitates the reactions from both directions of reduction and oxidation. • Degradation potential of aromatic amines depends on the substituted groups. • Cr(VI)–S(IV)–O{sub 2} system is promising for “waste control by waste”. - Abstract: Hexavalent chromium (Cr(VI)), a heavy-metal contaminant, can be easily reduced to less toxic trivalent chromium (Cr(III)) by sulfite ions (S(IV)). However, S(IV) has not drawn as much attention as the ferrous ion has. We report herein a novel Cr(VI)–S(IV)–O{sub 2} system containing sulfite ions that rapidly and simultaneously reduces Cr(VI) and oxidize organic pollutants in the presence of oxygen in aqueous solutions. This Cr(VI)–S(IV)-O{sub 2} system contains the initiator Cr(VI), the reductant S(IV), and the oxidant O{sub 2}, which produce oxysulfur radicals (mainly SO{sub 4}·{sup −} and SO{sub 5}·{sup −}) and hydroxyl radicals (OH·). The Cr(VI)/S(IV) molar ratio, pH, and oxygen content play important roles in the entire reaction system. Acidic conditions (pH 3.0) facilitated degradation of organic compounds and reduction of Cr(VI) as well. In addition, experiments of rapid degradation of several kinds of organic pollutants such as azo dye (acid orange 7, AO7), aniline, phenol, bisphenol A etc were also conducted. Preliminary results show that the removal rates of the analogs of phenols or aromatic amines in this Cr(VI)–S(IV)–O{sub 2} system have a relationship with the electronic parameters (Hammett constant, σ) of the substituted groups. Thus, the Cr(VI)–S(IV)–O{sub 2} system, provides an excellent strategy of “waste control by waste” for removing multiple industrial contaminants.

  7. Rapid calculation of protein chemical shifts using bond polarization theory and its application to protein structure refinement.

    Science.gov (United States)

    Jakovkin, Igor; Klipfel, Marco; Muhle-Goll, Claudia; Ulrich, Anne S; Luy, Burkhard; Sternberg, Ulrich

    2012-09-21

    Although difficult to analyze, NMR chemical shifts provide detailed information on protein structure. We have adapted the semi-empirical bond polarization theory (BPT) to protein chemical shift calculation and chemical shift driven protein structure refinement. A new parameterization for BPT amide nitrogen chemical shift calculation has been derived from MP2 ab initio calculations and successfully evaluated using crystalline tripeptides. We computed the chemical shifts of the small globular protein ubiquitin, demonstrating that BPT calculations can match the results obtained at the DFT level of theory at very low computational cost. In addition to the calculation of chemical shift tensors, BPT allows the calculation of chemical shift gradients and consequently chemical shift driven geometry optimizations. We applied chemical shift driven protein structure refinement to the conformational analysis of a set of Trypanosoma brucei (the causative agent of African sleeping sickness) tryparedoxin peroxidase Px III structures. We found that the interaction of Px III with its reaction partner Tpx seems to be governed by conformational selection rather than by induced fit.

  8. Rapid analysis of formic acid, acetic acid, and furfural in pretreated wheat straw hydrolysates and ethanol in a bioethanol fermentation using atmospheric pressure chemical ionisation mass spectrometry

    Science.gov (United States)

    2011-01-01

    Atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) offers advantages as a rapid analytical technique for the quantification of three biomass degradation products (acetic acid, formic acid and furfural) within pretreated wheat straw hydrolysates and the analysis of ethanol during fermentation. The data we obtained using APCI-MS correlated significantly with high-performance liquid chromatography analysis whilst offering the analyst minimal sample preparation and faster sample throughput. PMID:21896164

  9. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  10. Improved magnetic and electrical properties of Cu doped Fe–Ni invar alloys synthesized by chemical reduction technique

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Sajjad, E-mail: sajjadhaleli@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ziya, Amer Bashir [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ashiq, Muhammad Naeem, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ibrahim, Ather; Atiq, Shabbar [Institute of Advanced Materials, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ahmad, Naseeb [Department of Physics, Government College University, Faisalabad (Pakistan); Shakeel, Muhammad [Institute of Advanced Materials, Bahauddin Zakariya University, Multan 60800 (Pakistan); Khan, Muhammad Azhar [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-12-01

    Fe–Ni–Cu invar alloys of various compositions (Fe{sub 65}Ni{sub 35−x}Cu{sub x}, x=0, 0.2, 0.6, 1, 1.4 and 1.8) were synthesized via chemical reduction route. These alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) techniques. The XRD analysis revealed the formation of face centered cubic (fcc) structure. The lattice parameter and the crystallite size of the investigated alloys were calculated and the line broadening indicated the nano-crystallites size of alloy powder. The particle size was estimated from SEM and it decreases by the incorporation of Cu and found to be in the range of 24–40 nm. The addition of Cu in these alloys appreciably enhances the saturation magnetization and it increases from 99 to 123 emu/g. Electrical conductivity has been improved with Cu addition. The thermal conductivity was calculated using the Wiedemann–Franz law. - Graphical abstract: M–H loops of Fe{sub 65}Ni{sub 35−x}Cu{sub x} x =0, 0.2, 0.6, 1, 1.4, 1.8 nano-invar alloys. - Highlights: • A simple method has been employed for the synthesis of invar alloys. • The magnetic properties has been enhanced by the Cu content. • The electrical conductivity has been improved.

  11. Investigating the Formation Process of Sn-Based Lead-Free Nanoparticles with a Chemical Reduction Method

    Directory of Open Access Journals (Sweden)

    Weipeng Zhang

    2013-01-01

    Full Text Available Nanoparticles of a promising lead-free solder alloy (Sn3.5Ag (wt.%, SnAg and Sn3.0Ag0.5Cu (wt.%, SAC were synthesized through a chemical reduction method by using anhydrous ethanol and 1,10-phenanthroline as the solvent and surfactant, respectively. To illustrate the formation process of Sn-Ag alloy based nanoparticles during the reaction, X-ray diffraction (XRD was used to investigate the phases of the samples in relation to the reaction time. Different nucleation and growth mechanisms were compared on the formation process of the synthesized nanoparticles. The XRD results revealed different reaction process compared with other researchers. There were many contributing factors to the difference in the examples found in the literature, with the main focus on the formation mechanism of crystal nuclei, the solubility and ionizability of metal salts in the solvent, the solid solubility of Cu in Ag nuclei, and the role of surfactant on the growth process. This study will help define the parameters necessary for the control of both the composition and size of the nanoparticles.

  12. Sulfur and ash reduction potential and selected chemical and physical properties of United States coals. [Contains glossary

    Energy Technology Data Exchange (ETDEWEB)

    Cavallaro, J.A.; Deurbrouck, A.W.; Killmeyer, R.P.; Fuchs, W. (USDOE Pittsburgh Energy Technology Center, PA (USA). Coal Preparation Div.); Jacobsen, P.S. (Burns and Roe Services Corp., Pittsburgh, PA (USA))

    1991-02-01

    This report presents the washability and comprehensive characterization results of 184 raw coal channel samples, including anthracite, bituminous and lignite coals, collected from the Central Region of the United States. This is the second of a three volume report on the coals of the United States. All the data are presented in six appendices. Statistical techniques and definitions are presented in Appendix A, and a glossary of terms is presented in Appendix B. The complete washability data and an in-depth characterization of each sample are presented alphabetically by state in Appendix C. In Appendix D, a statistical evaluation is given for the composited washability data, selected chemical and physical properties and washability data interpolated at various levels of Btu recovery. This presentation is shown by state, section, and region where four or more samples were collected. Appendix E presents coalbed codes and names for the Central Region coals. Graphical summations are presented by state, section and region showing the effects of crushing on impurity reductions, and the distribution of raw and clean coal samples meeting various levels of SO{sub 2} emissions. 35 figs., 5 tabs.

  13. Application of integrated ozone and granular activated carbon for decolorization and chemical oxygen demand reduction of vinasse from alcohol distilleries.

    Science.gov (United States)

    Hadavifar, Mojtaba; Younesi, Habibollah; Zinatizadeh, Ali Akbar; Mahdad, Faezeh; Li, Qin; Ghasemi, Zahra

    2016-04-01

    This study investigates the treatment of the distilleries vinasse using a hybrid process integrating ozone oxidation and granular activated carbons (GAC) in both batch and continuous operation mode. The batch-process studies have been carried out to optimize initial influent pH, GAC doses, the effect of the ozone (O3) and hydrogen peroxide (H2O2) concentrations on chemical oxygen demand (COD) and color removal of the distilleries vinasse. The continuous process was carried out on GAC and ozone treatment alone as well as the hybrid process comb both methods to investigate the synergism effectiveness of the two methods for distilleries vinasse COD reduction and color removal. In a continuous process, the Yan model described the experimental data better than the Thomas model. The efficiency of ozonation of the distilleries vinasse was more effective for color removal (74.4%) than COD removal (25%). O3/H2O2 process was not considerably more effective on COD and color removal. Moreover, O3/GAC process affected negatively on the removal efficiency by reducing COD and color from distilleries vinasse. The negative effect decreased by increasing pH value of the influent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. In situ chemical reductive growth of platinum nanoparticles on glass slide for the mass fabrication of biosensors.

    Science.gov (United States)

    Yang, Ming-Hui; Qu, Feng-Li; Lu, Ya-Shuang; Shen, Guo-Li; Yu, Ru-Qin

    2008-01-15

    Platinum nanoparticles (PtNPs) attached to glass slide surface was successfully prepared by using a simple in situ chemical reduction method. In this method, a approximately 10nm gold layer was first sputtered uniformly onto the glass slide surface, PtNPs could be grown directly on the gold layer by immersing the glass slide into the grown solution containing H(2)PtCl(4) and ascorbic acid. The gold layer sputtered uniformly serves as "seed" for the following growth of PtNPs and high dense of PtNP modified film can be prepared. Control experiment without the gold layer found no obvious formation of PtNPs indicating the importance of the "seed". The electrocatalytic effect of the PtNP film was investigated with the detection of hydrogen peroxide and for the fabrication of biosensors. Glucose oxidase was selected and directly electrodeposited onto the PtNPs modified surface. The resulting biosensor has a fast response time (nanoparticle and find electrochemical applications as well as for optical uses.

  15. Mitochondrial adaptations to high-volume exercise training are rapidly reversed after a reduction in training volume in human skeletal muscle.

    Science.gov (United States)

    Granata, Cesare; Oliveira, Rodrigo S F; Little, Jonathan P; Renner, Kathrin; Bishop, David J

    2016-10-01

    Increased mitochondrial content and respiration have both been reported after exercise training. However, no study has directly compared how different training volumes influence mitochondrial respiration and markers of mitochondrial biogenesis. Ten healthy men performed high-intensity interval cycling during 3 consecutive training phases; 4 wk of normal-volume training (NVT; 3/wk), followed by 20 d of high-volume training (HVT; 2/d) and 2 wk of reduced-volume training (RVT; 5 sessions). Resting biopsy samples (vastus lateralis) were obtained at baseline and after each phase. No mitochondrial parameter changed after NVT. After HVT, mitochondrial respiration and citrate synthase activity (∼40-50%), as well as the protein content of electron transport system (ETS) subunits (∼10-40%), and that of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), NRF1, mitochondrial transcription factor A (TFAM), PHF20, and p53 (∼65-170%) all increased compared to baseline; mitochondrial specific respiration remained unchanged. After RVT, all the mitochondrial parameters measured except citrate synthase activity (∼36% above initial) were not significantly different compared to baseline (all P > 0.05). Our findings demonstrate that training volume is an important determinant of training-induced mitochondrial adaptations and highlight the rapid reversibility of human skeletal muscle to a reduction in training volume.-Granata, C., Oliveira, R. S. F., Little, J. P., Renner, K., Bishop, D. J. Mitochondrial adaptations to high-volume exercise training are rapidly reversed after a reduction in training volume in human skeletal muscle. © FASEB.

  16. The efficacy of chemical sanitizers on the reduction of Salmonella Typhimurium and Escherichia coli affected by bacterial cell history and water quality

    NARCIS (Netherlands)

    Banach, J.L.; Bokhorst-van de Veen, van H.; Overbeek, van L.S.; Zouwen, van der P.S.; Fels, van der Ine; Nierop Groot, M.N.

    2017-01-01

    Washing fresh produce with potable water helps to remove microorganisms, providing about a 1- to 2-log reduction, but this process can also pose an opportunity for cross-contamination of bacteria in the washing tank. The objective of this study was to evaluate the efficacy of three chemical

  17. Effect of Mindfulness Based Stress Reduction on Quality of Life (SF-36) and Spirometry Parameters, in Chemically Pulmonary Injured Veterans

    Science.gov (United States)

    AREFNASAB, Zahra; GHANEI, Mostafa; NOORBALA, Ahmad Ali; ALIPOUR, Ahmad; BABAMAHMOODI, Farhang; BABAMAHMOODI, Abdolreza; SALEHI, Maryam

    2013-01-01

    Abstract Background Studies have shown that Mindfulness Based Stress Reduction (MBSR) has positive effect on physical and psychological dimensions of chronic illnesses. In this study for the first time we examine the effect of this new technique on quality of life and pulmonary function in chemically pulmonary injured veterans who have chronic pulmonary problem, psychological problems and low quality of life. Methods Forty male pulmonary injured veterans were randomly replaced in two groups with 20 participants (MBSR and control Wait List (WL)). Then MBSR group received 8-weekly sessions intervention. We evaluate quality of life (used SF-36 questionnaire) and Spirometry parameters two times; before and after intervention in two group. We used “mixed factorial analyses of variance” test for analyzing data in each dependent variables. Then if we have significant interactional effect, we used –paired- sample t-test” for comparing before and after intervention data of each group, and “Independent-Sample t-test” for comparing after intervention data of two groups. Results The MBSR compare to WL group improved SF-36 total score, (F (1, 38) =12.09, P=0.001), “Role limitations due to physical problems”(F(1,38)= 6.92, P=0.01), “Role limitations due to emotional problems”(F(1,38)= 7.75, P=0.008), “Social functioning”(F(1,38)= 9.89, P=0.003), “Mental health”(F(1,38)= 15.93, P=0), “Vitality”(F(1,38)= 40.03, P≤0.001), and “Pain”(F(1,38)= 27.60, P≤0.001). MBSR had no significant effect on “FEV1” (F (1, 38) = 0.03, P=0.85),”FVC” (F (1, 38) = 0.16, P=0.69) and “FEV1/FVC” (F (1, 38) = 2.21, P=0.14). Conclusion MBSR can improve individual’s quality of life but not lung function in chemically pulmonary injured veterans. PMID:26060664

  18. Metabolic implications when employing heavy pre- and post-exercise rapid-acting insulin reductions to prevent hypoglycaemia in type 1 diabetes patients: a randomised clinical trial.

    Directory of Open Access Journals (Sweden)

    Matthew D Campbell

    Full Text Available To examine the metabolic, gluco-regulatory-hormonal and inflammatory cytokine responses to large reductions in rapid-acting insulin dose administered prandially before and after intensive running exercise in male type 1 diabetes patients.This was a single centre, randomised, controlled open label study. Following preliminary testing, 8 male patients (24±2 years, HbA1c 7.7±0.4%/61±4 mmol.l-1 treated with insulin's glargine and aspart, or lispro attended the laboratory on two mornings at ∼08:00 h and consumed a standardised breakfast carbohydrate bolus (1 g carbohydrate.kg-1BM; 380±10 kcal and self-administered a 75% reduced rapid-acting insulin dose 60 minutes before 45 minutes of intensive treadmill running at 73.1±0.9% VO2peak. At 60 minutes post-exercise, patients ingested a meal (1 g carbohydrate.kg-1BM; 660±21 kcal and administered either a Full or 50% reduced rapid-acting insulin dose. Blood glucose and lactate, serum insulin, cortisol, non-esterified-fatty-acids, β-Hydroxybutyrate, and plasma glucagon, adrenaline, noradrenaline, IL-6, and TNF-α concentrations were measured for 180 minutes post-meal.All participants were analysed. All glycaemic, metabolic, hormonal, and cytokine responses were similar between conditions up to 60 minutes following exercise. Following the post-exercise meal, serum insulin concentrations were lower under 50% (p<0.05 resulting in 75% of patients experiencing hyperglycaemia (blood glucose ≥8.0 mmol.l-1; 50% n = 6, Full n = 3. β-Hydroxybutyrate concentrations decreased similarly, such that at 180 minutes post-meal concentrations were lower than rest under Full and 50%. IL-6 and TNF-α concentrations remained similar to fasting levels under 50% but declined under Full. Under 50% IL-6 concentrations were inversely related with serum insulin concentrations (r = -0.484, p = 0.017.Heavily reducing rapid-acting insulin dose with a carbohydrate bolus before, and a meal after intensive

  19. Large Pre- and Postexercise Rapid-Acting Insulin Reductions Preserve Glycemia and Prevent Early- but Not Late-Onset Hypoglycemia in Patients With Type 1 Diabetes

    Science.gov (United States)

    Campbell, Matthew D.; Walker, Mark; Trenell, Michael I.; Jakovljevic, Djordje G.; Stevenson, Emma J.; Bracken, Richard M.; Bain, Stephen C.; West, Daniel J.

    2013-01-01

    OBJECTIVE To examine the acute and 24-h glycemic responses to reductions in postexercise rapid-acting insulin dose in type 1 diabetic patients. RESEARCH DESIGN AND METHODS After preliminary testing, 11 male patients (24 ± 2 years, HbA1c 7.7 ± 0.3%; 61 ± 3.4 mmol/mol) attended the laboratory on three mornings. Patients consumed a standardized breakfast (1 g carbohydrate ⋅ kg−1 BM; 380 ± 10 kcal) and self-administered a 25% rapid-acting insulin dose 60 min prior to performing 45 min of treadmill running at 72.5 ± 0.9% VO2peak. At 60 min postexercise, patients ingested a meal (1 g carbohydrate ⋅ kg−1 BM; 660 ± 21 kcal) and administered a Full, 75%, or 50% rapid-acting insulin dose. Blood glucose concentrations were measured for 3 h postmeal. Interstitial glucose was recorded for 20 h after leaving the laboratory using a continuous glucose monitoring system. RESULTS All glycemic responses were similar across conditions up to 60 min postexercise. After the postexercise meal, blood glucose was preserved under 50%, but declined under Full and 75%. Thence at 3 h, blood glucose was highest under 50% (50% [10.4 ± 1.2] vs. Full [6.2 ± 0.7] and 75% [7.6 ± 1.2 mmol ⋅ L−1], P = 0.029); throughout this period, all patients were protected against hypoglycemia under 50% (blood glucose ≤3.9; Full, n = 5; 75%, n = 2; 50%, n = 0). Fifty percent continued to protect patients against hypoglycemia for a further 4 h under free-living conditions. However, late-evening and nocturnal glycemia were similar; as a consequence, late-onset hypoglycemia was experienced under all conditions. CONCLUSIONS A 25% pre-exercise and 50% postexercise rapid-acting insulin dose preserves glycemia and protects patients against early-onset hypoglycemia (≤8 h). However, this strategy does not protect against late-onset postexercise hypoglycemia. PMID:23514728

  20. Mechanochemical synthesis of Co and Ni decorated with chemically deposited Pt as electrocatalysts for oxygen reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Rojas, E.; Cabañas-Moreno, J.G. [Programa de Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Av. Instituto Politécnico Nacional 2508, Col. Zacatenco, 07360 Mexico City (Mexico); Pérez-Robles, J.F. [Programa de Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Av. Instituto Politécnico Nacional 2508, Col. Zacatenco, 07360 Mexico City (Mexico); Dpto. Ciencia de los Materiales, CINVESTAV-IPN Unidad Queretaro, Libramiento Norponiente No. 2000 Fracc. Real de Juriquilla, 76230, Queretaro (Mexico); Solorza-Feria, O., E-mail: osolorza@cinvestav.mx [Programa de Nanociencias y Nanotecnología, Centro de Investigación y de Estudios Avanzados, CINVESTAV-IPN, Av. Instituto Politécnico Nacional 2508, Col. Zacatenco, 07360 Mexico City (Mexico); Depto. Química, CINVESTAV-IPN, 07360, México City (Mexico)

    2016-11-01

    High energy milling in combination with galvanic displacement were used for the preparation of bimetallic nanocatalysts. Co and Ni monometallic powders milled for 30 and 20 h, respectively were both produced in air atmosphere and used as precursors for the preparation of M-Pt (M = Co,Ni) compounds. Nanosized monometallic powders were physically supported on Vulcan carbon, and covered with 20 wt%Pt through a Galvanic Displacement Reaction (GDR) to produce Co-20Pt/C and Ni-20Pt/C electrocatalysts. XRD was used for phase identification on milled powders and for demonstrating structural transformations of Co powders during milling. Results on unmilled metallic Co powder show a predominant HCP structure modifying to a FCC structure after milling. Ni powders maintain their same FCC structure. Energy Dispersive X-Ray Spectometry (EDX) was used for chemical composition analysis on milled powders at several milling times. Scanning Transmission Electron Microscopy (STEM) show the formation of heterogeneous particle with ∼10 nm in size for both electrocatalysts. The electrocatalytic activity was evaluated by Cyclic Voltammetry (CV) and steady state Rotating Disk Electrode (RDE) for the Oxygen Reduction Reaction (ORR) in 0.1 M HClO{sub 4}. The kinetic parameters on Co-20Pt/C conducted to the highest mass activity for the cathodic reaction. - Highlights: • Monometallic powders of Co, and Ni were used as precursors for the preparation of M-Pt (M = Co,Ni) electrocatalysts. • Nanosized monometallic powders were decorated with Pt by a Galvanic Displacement Reaction. • The kinetic parameters on Co-20Pt/C conducted to the highest mass activity for the ORR reaction.

  1. Mining Available Data from the United States Environmental Protection Agency to Support Rapid Life Cycle Inventory Modeling of Chemical Manufacturing

    Science.gov (United States)

    Demands for quick and accurate life cycle assessments create a need for methods to rapidly generate reliable life cycle inventories (LCI). Data mining is a suitable tool for this purpose, especially given the large amount of available governmental data. These data are typically a...

  2. Implementing a Systematic Process for Rapidly Embedding Sustainability within Chemical Engineering Education: A Case Study of James Cook University, Australia

    Science.gov (United States)

    Sheehan, Madoc; Schneider, Phil; Desha, Cheryl

    2012-01-01

    Sustainability has emerged as a primary context for engineering education in the 21st Century, particularly the sub-discipline of chemical engineering. However, there is confusion over how to go about integrating sustainability knowledge and skills systemically within bachelor degrees. This paper addresses this challenge, using a case study of an…

  3. Use of TSHβ:EGFP transgenic zebrafish as a rapid in vivo model for assessing thyroid-disrupting chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Cheng [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Jin, Xia; He, Jiangyan [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei (China); Yin, Zhan, E-mail: zyin@ihb.ac.cn [Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei (China)

    2012-07-15

    Accumulating evidence indicates that a wide range of chemicals have the ability to interfere with the hypothalamic–pituitary–thyroid (HPT) axis. Novel endpoints should be evaluated in addition to existing methods in order to effectively assess the effects of these chemicals on the HPT axis. Thyroid-stimulating hormone subunit β (TSHβ) plays central regulatory roles in the HPT system. We identified the regulatory region that determines the expression level of zebrafish TSHβ in the anterior pituitary. In the transgenic zebrafish with EGFP driven by the TSHβ promoter, the similar responsive patterns between the expression levels of TSHβ:EGFP and endogenous TSHβ mRNA in the pituitary are observed following treatments with goitrogen chemicals and exogenous thyroid hormones (THs). These results suggest that the TSHβ:EGFP transgenic reporter zebrafish may be a useful alternative in vivo model for the assessment of chemicals interfering with the HPT system. Highlights: ► The promoter of zebrafish TSHβ gene has been identified. ► The stable TSHβ:EGFP transgenic zebrafish reporter germline has been generated. ► The EGFP in the transgenic fish recapitulated the pattern of pituitary TSHβ mRNA. ► The transgenic zebrafish may be an in vivo model for EDC assessment.

  4. Rapid prototyping of nano- and micro-patterned substrates for the control of cell neuritogenesis by topographic and chemical cues

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ajay V.; Gailite, Lasma; Vyas, Varun [European School of Molecular Medicine (SEMM), IFOM-IEO Campus, Via Adamello 16, I-20139 Milano (Italy); CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Lenardi, Cristina, E-mail: cristina.lenardi@mi.infn.it [CIMAINA and Dipartimento di Scienze Molecolari Applicate ai Biosistemi, Universita di Milano, via Trentacoste 2, I-20134 Milano (Italy); Fondazione Filarete, viale Ortles 22/4, I-20139 Milano (Italy); Forti, Stefania [CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Matteoli, Michela [Dipartimento di Farmacologia, Chemioterapia e Tossicologia Medica, Universita di Milano, via Vanvitelli 32, I-20139 Milano (Italy); Fondazione Filarete, viale Ortles 22/4, I-20139 Milano (Italy); Milani, Paolo, E-mail: paolo.milani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, I-20133 Milano (Italy); Fondazione Filarete, viale Ortles 22/4, I-20139 Milano (Italy)

    2011-07-20

    Rapid prototyping of titania substrates with micro and nanofeatures is obtained by combining nanosphere lithography with supersonic cluster beam deposition on protein-functionalized glass supports. The proliferation and differentiation of PC12 cells were studied on these substrates. The facile control and modification of the substrate structure at the micro- and nanoscale allowed us to characterize the role of functional and structural features on neuritogenesis and to control this phenomenon by identifying the optimal topography.

  5. Selective colorimetric sensors based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction for a simple and rapid determination of mercury

    Science.gov (United States)

    Jarujamrus, Purim; Amatatongchai, Maliwan; Thima, Araya; Khongrangdee, Thatsanee; Mongkontong, Chakrit

    2015-05-01

    In this work, selective colorimetric sensors for simple and rapid detection of Hg(II) ions based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction were developed. The average diameter of synthesized AgNPs was 8.3 ± 1.4 nm which was characterized by transmission electron microscopy (TEM). The abrupt change in absorbance of the unmodified AgNPs was observed which progressively decreased and slightly shifted to the blue wavelength as the concentration of Hg(II) increased, indicating the oxidation of Ag(0) to Ag(I) occurred. It appears that the AgNPs were oxidized by Hg(II), resulting in disintegration of the AgNPs into smaller particles as well as mediating the reduction of Hg(II) to Hg(0) adsorbed onto the surface of AgNPs. The adsorption of Hg(0) resulted in the lack of sufficient charges on AgNPs surfaces due to the decrease in the surface coverage of negatively charged citrate molecules, which then leaded to enlargement of AgNPs. The calibration curve of this technique was demonstrated from 0.5 to 7 ppm (r2 = 0.995), the limit of detection (LOD) was 0.06 ppm (SDblank/slope of calibration curve) with the precision (RSD, n = 4) of 3.24-4.53. Interestingly, the results show a significant enhance in the Hg(II) analytical sensitivity when Cu(II) is doped onto the unmodified AgNPs, which improves the quantitative detection limit to 0.008 ppm. In addition, greater selectivity toward Hg(II) compared with the other metal ions tested was observed. Furthermore, the percentage recoveries of spiked drinking water, tap water and SRM1641d (mercury in water) were in acceptable range with a good precision (RSD) which were in agreement with the values obtained from graphite furnace atomic absorption spectrometer (GFAAS). The technique proposed in this study provides a rapid, simple, sensitive and selective detection method for Hg(II) in water samples.

  6. Reduction of carbon dioxide gas formation at the anode of a direct methanol fuel cell using chemically enhanced solubility

    Science.gov (United States)

    Lundin, Michael D.; McCready, Mark J.

    The production of CO 2 gas at the DMFC anode leads to dramatic increases in pumping power requirements and reduced power output because of mass transfer limitations as bubble trains form in the channels of larger stacks. Experimental observations taken in a 5 cm 2 DMFC test cell operated at 60 °C, 1 atm, and with a methanol/water fuel flow rates of 5-10 cm 3 min -1 indicate that the rate of bubble formation can be reduced by increasing the fuel flow because more liquid is available for the CO 2 to dissolve in. Further observations indicate that KOH and LiOH added to the fuel eliminates CO 2 gas formation in situ at low concentrations because of the greatly increased solubility that results. A mathematical model for the volumetric rate of CO 2 gas production that includes effects of temperature and solubility is developed and extended to include the effects of hydroxide ions in solution. The model is used to predict the onset location of gas formation in the flow field as well as the void fraction at any point in the flow field. Predictions from the model agree very well with our experiments. Model predictions explain differences in the initial location of bubble formation for fuel solutions pre-saturated with CO 2 as opposed to CO 2-free solutions. Experiments with KOH and LiOH added to fuel solutions confirm the validity of the model extension that includes solubility that is enhanced by chemical reaction. Experiments with LiOH, KOH, and ammonium hydroxide show that the long-term durability of standard Pt-Ru/Nafion ®/Pt membrane electrode assemblies is compromised because of the presence of lithium, potassium, and ammonium cations that interact with the Nafion ® membrane and result in increasing the ohmic limitations of the polymer electrolyte membrane. Experiments with Ca(OH) 2, while reducing gas formation, precipitate the product CaCO 3 out of solution too rapidly for downstream filtering, blocking channels in the flow field.

  7. Solid-phase microextraction low temperature plasma mass spectrometry for the direct and rapid analysis of chemical warfare simulants in complex mixtures.

    Science.gov (United States)

    Dumlao, Morphy C; Jeffress, Laura E; Gooding, J Justin; Donald, William A

    2016-06-21

    Solid-phase microextraction (SPME) is directly integrated with low temperature plasma ionisation mass spectrometry to rapidly detect organophosphate chemical warfare agent simulants and their hydrolysis products in chemical mixtures, including urine. In this sampling and ionization method, the fibre serves: (i) to extract molecules from their native environment, and (ii) as the ionization electrode that is used to desorb and ionize molecules directly from the SPME surface. By use of a custom fabricated SPME fibre consisting of a stainless steel needle coated with a Linde Type A (LTA) zeolitic microporous material and low temperature plasma mass spectrometry, protonated dimethyl methylphosphonate (DMMP), diethyl ethylphosphonate (DEEP) and pinacolyl methylphosphonic acid (PinMPA) can be detected at less than 100 ppb directly in water and urine. Organophosphates were not readily detected by this approach using an uncoated needle in negative control experiments. The use of the LTA coating significantly outperformed the use of a high alumina Zeolite Socony Mobil-5 (ZSM-5) coating of comparable thickness that is significantly less polar than LTA. By conditioning the LTA probe by immersion in an aqueous CuSO4 solution, the ion abundance for protonated DMMP increased by more than 300% compared to that obtained without any conditioning. Sample recovery values were between 96 and 100% for each analyte. The detection of chemical warfare agent analogues and hydrolysis products required less than 2 min per sample. A key advantage of this sampling and ionization method is that analyte ions can be directly and rapidly sampled from chemical mixtures, such as urine and seawater, without sample preparation or chromatography for sensitive detection by mass spectrometry. This ion source should prove beneficial for portable mass spectrometry applications because relatively low detection limits can be obtained without the use of compressed gases, fluid pumps, and lasers. Moreover, the

  8. Microwave assisted rapid growth of Mg(OH){sub 2} nanosheet networks for ethanol chemical sensor application

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hazmi, Faten [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Umar, Ahmad, E-mail: ahmadumar786@gmail.com [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Dar, G.N. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Ghamdi, A.A.; Al-Sayari, S.A. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Al-Hajry, A. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Department of Physics, College of Science and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Kim, S.H. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Tuwirqi, Reem M. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Alnowaiserb, Fowzia [Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt)

    2012-04-05

    Highlights: Black-Right-Pointing-Pointer A facile microwave-assisted synthesis and characterizations of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Fabrication of ethanol sensor based on (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M). Black-Right-Pointing-Pointer This research opens a way to utilize Mg(OH){sub 2} nanostructures for chemical sensors applications. - Abstract: This paper reports a facile microwave-assisted synthesis of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks and their utilization for the fabrication of efficient ethanol chemical sensor. The synthesized nanosheets networks were characterized in terms of their morphological, structural and optical properties using various analysis techniques such as field emission scanning electron microscopy (FESEM), X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The detailed morphological and structural investigations reveal that the synthesized (Mg(OH){sub 2}) products are nanosheet networks, grown in high density, and possessing hexagonal crystal structure. The optical band gap of as-synthesized Mg(OH){sub 2} nanosheet networks was examined by UV-Vis absorption spectrum, and found to be 5.76 eV. The synthesized nanosheet networks were used as supporting matrices for the fabrication of I-V technique based efficient ethanol chemical sensor. The fabricated ethanol sensor based on nanosheet networks exhibits good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M), with linearity (R = 0.9925) in short response time (10.0 s). This work demonstrate that the simply synthesized Mg(OH){sub 2} nanosheet networks can effectively be used for the fabrication of efficient ethanol chemical sensors.

  9. Rapid Monitoring of Mercury in Air from an Organic Chemical Factory in China Using a Portable Mercury Analyzer

    OpenAIRE

    Yasutake, Akira; Cheng, Jin Ping; Kiyono, Masako; Uraguchi, Shimpei; Liu, Xiaojie; Miura, Kyoko; Yasuda, Yoshiaki; Mashyanov, Nikolay

    2011-01-01

    A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m3 in air o...

  10. Detection and reduction of diffuse liquid and gas emissions in chemical and petrochemical industries; Ermittlung und Verminderung diffuser fluessiger und gasfoermiger Emissionen in der chemischen und petrochemischen Industrie

    Energy Technology Data Exchange (ETDEWEB)

    Koeppke, K.E. [Witten-Herdecke Univ. gGmbH, Witten (Germany). Inst. fuer Umwelttechnik und Management; Cuhls, C. [Halle-Wittenberg Univ., Halle (Germany). Inst. fuer Umwelttechnik

    2002-09-01

    In order to improve environmental protection, VOC emissions from diffuse sources are of growing importance. For the first time in Germany the present research report gives a detailed presentation of: constructive measures for the avoidance and reduction of diffuse emissions, adequate assembling procedures for equipments and installations, technical possibilities of leak detection and, different methods for the estimation of total emissions from chemical and petrochemical production plants. On the basis of own investigations and monitoring measures taken at various plants of chemical and petrochemical industries different measuring techniques for leak detection as well as methods for the estimation of total emissions from diffuse sources are analysed and their limits are described. (orig.)

  11. Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial.

    Science.gov (United States)

    Ross, Stephen; Bossis, Anthony; Guss, Jeffrey; Agin-Liebes, Gabrielle; Malone, Tara; Cohen, Barry; Mennenga, Sarah E; Belser, Alexander; Kalliontzi, Krystallia; Babb, James; Su, Zhe; Corby, Patricia; Schmidt, Brian L

    2016-12-01

    Clinically significant anxiety and depression are common in patients with cancer, and are associated with poor psychiatric and medical outcomes. Historical and recent research suggests a role for psilocybin to treat cancer-related anxiety and depression. In this double-blind, placebo-controlled, crossover trial, 29 patients with cancer-related anxiety and depression were randomly assigned and received treatment with single-dose psilocybin (0.3 mg/kg) or niacin, both in conjunction with psychotherapy. The primary outcomes were anxiety and depression assessed between groups prior to the crossover at 7 weeks. Prior to the crossover, psilocybin produced immediate, substantial, and sustained improvements in anxiety and depression and led to decreases in cancer-related demoralization and hopelessness, improved spiritual wellbeing, and increased quality of life. At the 6.5-month follow-up, psilocybin was associated with enduring anxiolytic and anti-depressant effects (approximately 60-80% of participants continued with clinically significant reductions in depression or anxiety), sustained benefits in existential distress and quality of life, as well as improved attitudes towards death. The psilocybin-induced mystical experience mediated the therapeutic effect of psilocybin on anxiety and depression. In conjunction with psychotherapy, single moderate-dose psilocybin produced rapid, robust and enduring anxiolytic and anti-depressant effects in patients with cancer-related psychological distress. ClinicalTrials.gov Identifier: NCT00957359. © The Author(s) 2016.

  12. Rapid thermal reduced graphene oxide/Pt-TiO2 nanotube arrays for enhanced visible-light-driven photocatalytic reduction of CO2

    Science.gov (United States)

    Sim, Lan Ching; Leong, Kah Hon; Saravanan, Pichiah; Ibrahim, Shaliza

    2015-12-01

    In this study, a complicate natural photosynthesis process was prototyped through a photocatalysis process by reducing CO2 to light hydrocarbon, CH4. The composite photocatalyst employed for this study utilized Pt nanoparticles (Pt NPs) and rapid thermal reduced graphene oxide (RGO) deposited over the surface of the TiO2 nanotube arrays (TNTs). The existence and contribution of both Pt NPs and RGO in the composite was confirmed through various analytical techniques including XRD, HRTEM, FESEM, Raman, FTIR, XPS, UV-DRS and photoluminescence (PL) analysis. The TNTs in the composite exhibited pure anatase phase. The absorption bands at around 450 nm obtained from UV-DRS spectrum supported the existence of LSPR phenomenon of Pt NPs. The promising lower work function of RGO promoted the electrons transfer from TNTs to RGO efficiently. The successful depositions of Pt and RGO onto the surface of TNTs contributed for the improved photocatalytic activity (total CH4 yield of 10.96 μmol m-2) in the reduction of CO2 over TNTs and Pt-TNTs. Both of RGO and Pt NPs are equally important to exert a significant impact on the improvement of CH4 production rates.

  13. Preparation of multilocation reduction-sensitive core crosslinked folate-PEG-coated micelles for rapid release of doxorubicin and tariquidar to overcome drug resistance

    Science.gov (United States)

    Yi, Xiaoqing; Zhao, Dan; Zhang, Quan; Xu, Jiaqi; Yuan, Gongdao; Zhuo, Renxi; Li, Feng

    2017-02-01

    Herein, we prepared folate-targeting core crosslinked polymeric micelles (CCL/FA) containing multiple disulfide bonds located at the interface and core of the micelles to co-deliver doxorubicin (DOX) and the P-glycoprotein (P-gp) inhibitor tariquidar (TQR) for reversing drug resistance. The stability and redox-responsive behavior of the CCL/FA micelles was evaluated through the changes in morphology, molecular weight and hydrodynamic size. On the one hand, the micelles possessed good stability, which led to the suppression of drug release from the CCL micelles in the physiological environment. On the other hand, under reductive conditions, the CCL micelles collapsed rapidly and accelerated drug release markedly. In vitro cytotoxicity measurements, combined with confocal laser scanning microscopy (CLSM) and flow cytometry, confirmed that the dual-drug-loaded micelles exhibited obviously higher cytotoxicity to MCF-7/ADR-resistant cells than free DOX · HCl, single-drug loaded CCL micelles and nontargeted CCL micelles. The results imply that co-delivering DOX and TQR by CCL/FA micelles may be a promising way of overcoming multidrug resistance in tumor treatments.

  14. Beam loss reduction by injection painting in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    Directory of Open Access Journals (Sweden)

    H. Hotchi

    2012-04-01

    Full Text Available The 3-GeV rapid cycling synchrotron (RCS of the Japan Proton Accelerator Research Complex was commissioned in October 2007. Via the initial beam tuning and a series of underlying beam studies with low-intensity beams, since December 2009, we have intermittently been performing beam tuning experiments with higher-intensity beams including the injection painting technique. By optimizing the injection painting parameters, we have successfully achieved a 420 kW-equivalent output intensity at a low-level intensity loss of less than 1%. Also the corresponding numerical simulation well reproduced the observed painting parameter dependence on the beam loss, and captured a characteristic behavior of the high-intensity beam in the injection painting process. In this paper, we present the experimental results obtained in the course of the RCS beam power ramp-up, especially on the beam loss reduction achieved by employing the injection painting, together with the numerical simulation results.

  15. The Chemical Deposition Method for the Decoration of Palladium Particles on Carbon Nanofibers with Rapid Conductivity Changes

    Directory of Open Access Journals (Sweden)

    Hoik Lee

    2016-11-01

    Full Text Available Palladium (Pd metal is well-known for hydrogen sensing material due to its high sensitivity and selectivity toward hydrogen, and is able to detect hydrogen at near room temperature. In this work, palladium-doped carbon nanofibers (Pd/CNFs were successfully produced in a facile manner via electrospinning. Well-organized and uniformly distributed Pd was observed in microscopic images of the resultant nanofibers. Hydrogen causes an increment in the volume of Pd due to the ability of hydrogen atoms to occupy the octahedral interstitial positions within its face centered cubic lattice structure, resulting in the resistance transition of Pd/CNFs. The resistance variation was around 400%, and it responded rapidly within 1 min, even in 5% hydrogen atmosphere conditions at room temperature. This fibrous hybrid material platform will open a new and practical route and stimulate further researches on the development of hydrogen sensing materials with rapid response, even to low concentrations of hydrogen in an atmosphere.

  16. Rapid screening and identification of chemical hazards in surface and drinking water using high resolution mass spectrometry and a case-control filter.

    Science.gov (United States)

    Kaserzon, Sarit L; Heffernan, Amy L; Thompson, Kristie; Mueller, Jochen F; Gomez Ramos, Maria Jose

    2017-09-01

    Access to clean, safe drinking water poses a serious challenge to regulators, and requires analytical strategies capable of rapid screening and identification of potentially hazardous chemicals, specifically in situations when threats to water quality or security require rapid investigations and potential response. This study describes a fast and efficient chemical hazard screening strategy for characterising trace levels of polar organic contaminants in water matrices, based on liquid chromatography high resolution mass spectrometry with post-acquisition 'case-control' data processing. This method allowed for a rapid response time of less than 24 h for the screening of target, suspect and non-target unknown chemicals via direct injection analysis, and a second, more sensitive analysis option requiring sample pre-concentration. The method was validated by fortifying samples with a range of pesticides, pharmaceuticals and personal care products (n = 46); with >90% of target compounds positively screened in samples at 1 ng mL-1, and 46% at 0.1 ng mL-1 when analysed via direct injection. To simulate a contamination event samples were fortified with compounds not present in the commercial library (designated 'non-target compounds'; fipronil and fenitrothion), tentatively identified at 0.2 and 1 ng mL-1, respectively; and a compound not included in any known commercial library or public database (designated 'unknown' compounds; 8Cl- perfluorooctanesulfonic acid), at 0.8 ng mL-1. The method was applied to two 'real-case' scenarios: (1) the assessment of drinking water safety during a high-profile event in Brisbane, Australia; and (2) to screen treated, re-circulated drinking water and pre-treated (raw) water. The validated workflow was effective for rapid prioritisation and screening of suspect and non-target potential hazards at trace levels, and could be applied to a wide range of matrices and investigations where comparison of organic contaminants between

  17. Observing a Chemically and/or Climatically Important Volcano: Facilitating Rapid Response to an Unanticipated yet Inevitable Event

    Science.gov (United States)

    Kaye, J. A.

    2015-12-01

    A large volcanic event has the potential to influence the chemical and/or physical state of the Earth's atmosphere in a significant way. In particular, changes in the trace constituent and/or particulate composition of the stratosphere, as well as the temperature distribution of the troposphere and stratosphere can both take place (and persist over a period of time), as has been observed in several eruptions in recent years (e.g., the Mount Pinatubo eruption in 1991). Characterizing the impacts of these eruptions and predicting their impacts on the evolution of the atmosphere requires observations of gas and particle distributions over time period from as soon after eruption as possible to the longer time period over which the Earth system is affected. This characterization may make use of observation capabilities from ongoing surface-based and existing satellite-based observing systems, and can also benefit significantly from focused airborne campaigns that make use of both in situ and remote sensing instrumentation. This presentation will review the relevant surface- and space-based observing capability operated by NASA in the broader context of the global observing capabilities of the international community, and and will discuss potential approaches to airborne campaigns (platforms, sensors, systems, logistical consideration) that would provide the data most useful for both characterization and forecasting of both the chemical and climatic forcing and impacts associated with the eruption.

  18. Rapidly induced chemical defenses in maize stems and their effects on short-term growth of Ostrinia nubilalis.

    Science.gov (United States)

    Dafoe, Nicole J; Huffaker, Alisa; Vaughan, Martha M; Duehl, Adrian J; Teal, Peter E; Schmelz, Eric A

    2011-09-01

    Plants damaged by insect herbivory often respond by inducing a suite of defenses that can negatively affect an insect's growth and fecundity. Ostrinia nubilalis (European corn borer, ECB) is one of the most devastating insect pests of maize, and in the current study, we examined the early biochemical changes that occur in maize stems in response to ECB herbivory and how these rapidly induced defenses influence the growth of ECB. We measured the quantities of known maize defense compounds, benzoxazinoids and the kauralexin class of diterpenoid phytoalexins. ECB herbivory resulted in decreased levels of the benzoxazinoid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one)-β-D-glucopyranose (DIMBOA-Glc), and a corresponding increase in 2-(2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one)-β-D-glucopyranose (HDMBOA-Glc). Total quantities of benzoxazinoids and kauralexins were increased as early as 24 h after the initiation of ECB feeding. The plant hormones, jasmonic acid (JA) and ethylene (ET), and the transcripts encoding their key biosynthetic enzymes also accumulated in response to ECB herbivory, consistent with a role in defense regulation. The combined pharmacological application of JA and the ET precursor, 1-aminocyclopropane-1-carboxylic acid to stem internode tissue likewise resulted in changes in benzoxazinoids similar to that observed with ECB damage. Despite the fact that maize actively mounts a defense response to ECB stem feeding, no differences in percent weight gain were observed between ECB larvae that fed upon non-wounded control tissues compared to tissues obtained from plants previously subjected to 24 h ECB stem herbivory. These rapid defense responses in maize stems do not appear to negatively impact ECB growth, thus suggesting that ECB have adapted to these induced biochemical changes.

  19. A physicochemical descriptor-based scoring scheme for effective and rapid filtering of kinase-like chemical space

    Science.gov (United States)

    2012-01-01

    Background The current chemical space of known small molecules is estimated to exceed 1060 structures. Though the largest physical compound repositories contain only a few tens of millions of unique compounds, virtual screening of databases of this size is still difficult. In recent years, the application of physicochemical descriptor-based profiling, such as Lipinski's rule-of-five for drug-likeness and Oprea's criteria of lead-likeness, as early stage filters in drug discovery has gained widespread acceptance. In the current study, we outline a kinase-likeness scoring function based on known kinase inhibitors. Results The method employs a collection of 22,615 known kinase inhibitors from the ChEMBL database. A kinase-likeness score is computed using statistical analysis of nine key physicochemical descriptors for these inhibitors. Based on this score, the kinase-likeness of four publicly and commercially available databases, i.e., National Cancer Institute database (NCI), the Natural Products database (NPD), the National Institute of Health's Molecular Libraries Small Molecule Repository (MLSMR), and the World Drug Index (WDI) database, is analyzed. Three of these databases, i.e., NCI, NPD, and MLSMR are frequently used in the virtual screening of kinase inhibitors, while the fourth WDI database is for comparison since it covers a wide range of known chemical space. Based on the kinase-likeness score, a kinase-focused library is also developed and tested against three different kinase targets selected from three different branches of the human kinome tree. Conclusions Our proposed methodology is one of the first that explores how the narrow chemical space of kinase inhibitors and its relevant physicochemical information can be utilized to build kinase-focused libraries and prioritize pre-existing compound databases for screening. We have shown that focused libraries generated by filtering compounds using the kinase-likeness score have, on average, better docking

  20. In situ DART-MS as a Versatile and Rapid Dereplication Tool in Lichenology: Chemical Fingerprinting of Ophioparma ventosa.

    Science.gov (United States)

    Le Pogam, Pierre; Le Lamer, Anne-Cécile; Legouin, Béatrice; Boustie, Joël; Rondeau, David

    2016-11-01

    Lichens widely occur all over the world and are known to produce unique secondary metabolites with various biological activities. To develop high-throughput screening approaches requiring little to no sample preparation to alleviate the dereplication holdup and accelerate the discovery workflow of new structures from lichens. The extracellular distribution of lichen metabolites is incentive for in situ chemical profiling of lichens using the ambient mass spectrometry DART-MS. For this purpose, the chlorolichen Ophioparma ventosa, producing an array of lichen polyphenolics that encompass the main structural classes associated to lichen chemodiversity, represented a relevant model to assess the versatility of this platform. The feasibility of this approach was first established by analysing the pure compounds known from this species prior to being extended to different solid organs of the lichen. All tested compounds could be detected in positive and negative ion modes, most often with prevalent protonated or deprotonated molecules. Only depsides underwent a significant in-source fragmentation in both ionisation modes, which should be regarded as an added value for their structural elucidation. In situ DART-MS analyses of Ophioparma ventosa provided an extensive chemical profile and noteworthy pinpointed miriquidic acid, an unusual lichen depside so far unknown within this species. At last, in situ DART-MS granted a first insight into the distribution of the metabolites within the lichen. DART-MS represents a versatile tool to the wide field of lichenology, facilitating accelerated and sharp analyses of lichens and bypassing costly and tedious procedures of solvent extraction. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  1. A rapid chemical-genetic screen utilizing impaired movement phenotypes in C. elegans: Input into genetics of neurodevelopmental disorders.

    Science.gov (United States)

    Schmeisser, Kathrin; Fardghassemi, Yasmin; Parker, J Alex

    2017-07-01

    Autism spectrum disorder (ASD) is the most common neurodevelopmental disorder with a constantly increasing prevalence. Model organisms may be tools to identify underlying cellular and molecular mechanisms, as well as aid the discovery and development of novel therapeutic approaches. A simple animal such as the nematode Caenorhabditis elegans may provide insights into the extreme complexity of ASD genetics. Despite its potential, using C. elegans in ASD research is a controversial approach and has not yet been used extensively in this context. In this study, we present a screening approach of potential C. elegans mutants as potential ASD models. We screened these mutants for motor-deficiency phenotypes, which can be exploited to study underlying mechanisms of the disorder. Selected motor-deficient mutants were then used in a comprehensive drug screen of over 3900 compounds, including many FDA-approved and natural molecules, that were analyzed for their ability to suppress motility defects caused by ASD-associated gene orthologues. This genetic-chemical approach, i.e. establishing C. elegans models for ASD and screening of a well-characterized compound library, might be a promising first step to understand the mechanisms of how gene variations cause neuronal dysfunction, leading to ASD and other neurological disorders. Positively acting compounds could also be promising candidates for preclinical studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Rapid assessment of mid-infrared refractive index anisotropy using a prism coupler: chemical vapor deposited ZnS.

    Science.gov (United States)

    Qiao, H A; Lipschultz, Kristen A; Anheier, N C; McCloy, J S

    2012-05-01

    A state-of-the-art mid-infrared prism coupler was used to study suspected anisotropy in the refractive index of forward-looking-infrared grade chemical vapor deposited (CVD) zinc sulfide. Samples were prepared with columnar grain structure in and perpendicular to the sample plane, as well as from different depths in the CVD growth body. This study was motivated by the growing industry concern among optical design engineers, as well as developers of mid-infrared systems, over the reliability of historically accepted index data. Prior photoluminescence and x-ray diffraction measurements have suggested that refractive index may vary according to sample orientation with respect to the grain structure. Measurements were conducted to provide optical dispersion and thermal index (dn/dT) data at discrete laser wavelengths between 0.633 and 10.591 μm at two temperature set points (30 °C and 90 °C). Refractive index measurements between samples exhibited an average standard deviation comparable to the uncertainty of the prism coupler measurement (0.0004 refractive index units), suggesting that the variation in refractive index as a function of sample orientation and CVD deposition time is negligible and should have no impact on subsequent optical designs. Measured dispersion data at mid-infrared wavelengths were also found to agree well with prior published measurements.

  3. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes.

    Science.gov (United States)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

    2016-05-01

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11kg/m(3) of copper and 1.35kg/m(3) of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100-500nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Chemical-Induced Read-Through at Premature Termination Codons Determined by a Rapid Dual-Fluorescence System Based on S. cerevisiae.

    Directory of Open Access Journals (Sweden)

    Emiliano Altamura

    Full Text Available Nonsense mutations generate in-frame stop codons in mRNA leading to a premature arrest of translation. Functional consequences of premature termination codons (PTCs include the synthesis of truncated proteins with loss of protein function causing severe inherited or acquired diseases. A therapeutic approach has been recently developed that is based on the use of chemical agents with the ability to suppress PTCs (read-through restoring the synthesis of a functional full-length protein. Research interest for compounds able to induce read-through requires an efficient high throughput large scale screening system. We present a rapid, sensitive and quantitative method based on a dual-fluorescence reporter expressed in the yeast Saccharomyces cerevisiae to monitor and quantitate read-through at PTCs. We have shown that our novel system works equally well in detecting read-through at all three PTCs UGA, UAG and UAA.

  5. Structure-activity relations for Ni-containing zeolites during NO reduction. II. Role of the chemical state of Ni

    NARCIS (Netherlands)

    Mosqueda Jimenez, B.I.; Jentys, A.; Seshan, Kulathuiyer; Lercher, J.A.

    2003-01-01

    The influence of the metal in Ni-containing zeolites used as catalysts for the reduction of NO with propane and propene was studied. In the fresh catalysts, Ni is located in ion exchange positions for Ni/MOR, Ni/ZSM-5, and Ni/MCM-22. The formation of carbonaceous deposits, the removal of Al from

  6. Unlocking the Electrocatalytic Activity of Chemically Inert Amorphous Carbon-Nitrogen for Oxygen Reduction: Discerning and Refactoring Chaotic Bonds

    DEFF Research Database (Denmark)

    Zhang, Caihong; Zhang, Wei; Wang, Dong

    2017-01-01

    Mild annealing enables inactive nitrogen (N)-doped amorphous carbon (a-C) films abundant with chaotic bonds prepared by magnetron sputtering to become effective for the oxygen reduction reaction (ORR) by virtue of generating pyridinic N. The rhythmic variation of ORR activity elaborates well...... on the subtle evolution of the amorphous C−N bonds conferred by spectroscopic analysis....

  7. A rapid fabrication of C/C composites by a thermal gradient chemical vapor infiltration method with vaporized kerosene as a precursor

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jiping [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)]. E-mail: buickwang@hotmail.com; Qian Junmin [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Qiao Guanjun [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Jin Zhihao [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2007-01-15

    A thermal gradient, atmospheric pressure chemical vapor infiltration method with simultaneous vaporized kerosene as a precursor for rapid fabrication of C/C composites was studied. By this method, carbon felts (bulk density {approx}0.2 g cm{sup -3}) were densified to C/C composites with density of 1.67 and 1.71 g cm{sup -3} when prepared at 1050 and 1150 deg. C for 6 h, respectively. X-ray diffraction result indicates that the composites have a strong ability to graphitize and the higher deposition temperature leads to the increased graphitization degree. Polarized light microscope and scanning electron microscope images reveal that fibers of the composites prepared for 6 h are surrounded by ring-shaped pyrocarbon matrix with a thickness of {approx}20 {mu}m, and that the matrix is delaminated to 4-6 layer-like regions. The deposition process is analyzed by dividing the reactor into four regions associated with specific functions and the reasons for the rapid fabrication are proposed as the short convection and diffusion path for the precursor and the existing of thermal gradient across the preform.

  8. Reduction of anti-malarial consumption after rapid diagnostic tests implementation in Dar es Salaam: a before-after and cluster randomized controlled study

    Directory of Open Access Journals (Sweden)

    Swai Ndeniria

    2011-04-01

    Full Text Available Abstract Background Presumptive treatment of all febrile patients with anti-malarials leads to massive over-treatment. The aim was to assess the effect of implementing malaria rapid diagnostic tests (mRDTs on prescription of anti-malarials in urban Tanzania. Methods The design was a prospective collection of routine statistics from ledger books and cross-sectional surveys before and after intervention in randomly selected health facilities (HF in Dar es Salaam, Tanzania. The participants were all clinicians and their patients in the above health facilities. The intervention consisted of training and introduction of mRDTs in all three hospitals and in six HF. Three HF without mRDTs were selected as matched controls. The use of routine mRDT and treatment upon result was advised for all patients complaining of fever, including children under five years of age. The main outcome measures were: (1 anti-malarial consumption recorded from routine statistics in ledger books of all HF before and after intervention; (2 anti-malarial prescription recorded during observed consultations in cross-sectional surveys conducted in all HF before and 18 months after mRDT implementation. Results Based on routine statistics, the amount of artemether-lumefantrine blisters used post-intervention was reduced by 68% (95%CI 57-80 in intervention and 32% (9-54 in control HF. For quinine vials, the reduction was 63% (54-72 in intervention and an increase of 2.49 times (1.62-3.35 in control HF. Before-and-after cross-sectional surveys showed a similar decrease from 75% to 20% in the proportion of patients receiving anti-malarial treatment (Risk ratio 0.23, 95%CI 0.20-0.26. The cluster randomized analysis showed a considerable difference of anti-malarial prescription between intervention HF (22% and control HF (60% (Risk ratio 0.30, 95%CI 0.14-0.70. Adherence to test result was excellent since only 7% of negative patients received an anti-malarial. However, antibiotic

  9. Rapid and automatic chemical identification of the medicinal flower buds of Lonicera plants by the benchtop and hand-held Fourier transform infrared spectroscopy

    Science.gov (United States)

    Chen, Jianbo; Guo, Baolin; Yan, Rui; Sun, Suqin; Zhou, Qun

    2017-07-01

    With the utilization of the hand-held equipment, Fourier transform infrared (FT-IR) spectroscopy is a promising analytical technique to minimize the time cost for the chemical identification of herbal materials. This research examines the feasibility of the hand-held FT-IR spectrometer for the on-site testing of herbal materials, using Lonicerae Japonicae Flos (LJF) and Lonicerae Flos (LF) as examples. Correlation-based linear discriminant models for LJF and LF are established based on the benchtop and hand-held FT-IR instruments. The benchtop FT-IR models can exactly recognize all articles of LJF and LF. Although a few LF articles are misjudged at the sub-class level, the hand-held FT-IR models are able to exactly discriminate LJF and LF. As a direct and label-free analytical technique, FT-IR spectroscopy has great potential in the rapid and automatic chemical identification of herbal materials either in laboratories or in fields. This is helpful to prevent the spread and use of adulterated herbal materials in time.

  10. A controlled study of the effect of a mindfulness-based stress reduction technique in women with multiple chemical sensitivity, chronic fatigue syndrome, and fibromyalgia

    Directory of Open Access Journals (Sweden)

    Tara Sampalli

    2009-04-01

    Full Text Available Tara Sampalli1, Elizabeth Berlasso1, Roy Fox1, Mark Petter21Nova Scotia Environmental Health Centre, Fall River, Nova Scotia, Canada; 2Doctoral Candidate, Department of Psychology, Dalhousie University, Halifax, CanadaBackground: The objective of this study was to examine the effect of a mindfulness-based stress reduction (MBSR program on women diagnosed with conditions such as multiple chemical sensitivity (MCS, chronic fatigue syndrome (CFS, and fibromyalgia (FM. Methods: The intervention group underwent a 10-week MBSR program. Symptoms Checklist Inventory (SCL-90R was used as outcome measure and was administered before the start of the program (pre-, immediately upon completion (post- and at three-month follow-up. Women on the wait list to receive treatment at the Nova Scotia Environmental Health Centre were used as control subjects for the study.Results: A total of 50 participants in the intervention group and 26 in the wait-list controls group were recruited for this study. Global scores in the intervention group reached statistical significance pre-post (<0.0001 and at pre-follow-up (<0.0001 while the global scores in the control group remained the same. Five of nine and eight of nine subscales of the SCL-90R showed improvement of statistical significance in MBSR group following treatment and at three-month follow-up.Conclusions: The study showed the importance of complementary interventions such as MBSR techniques in the reduction of psychological distress in women with chronic conditions.Keywords: chronic conditions, multiple chemical sensitivity, mindfulness-based stress reduction, chemical sensitivity

  11. On the Theory of Oxidation-Reduction Reactions Involving Electron Transfer. V. Comparison and Properties of Electrochemical and Chemical Rate Constants

    Science.gov (United States)

    Marcus, R. A.

    1962-01-01

    Using a theory of electron transfers which takes cognizance of reorganization of the medium outside the inner coordination shell and of changes of bond lengths inside it, relations between electrochemical and related chemical rate constants are deduced and compared with the experimental data. A correlation is found, without the use of arbitrary parameters. Effects of weak complexes with added electrolytes are included under specified conditions. The deductions offer a way of coordinating a variety of data in the two fields, internally as well as with each those in another. For example, the rate of oxidation or reduction of a series of related reactants by one reagent is correlated with that of another and with that of the corresponding electrochemical oxidation-reduction reaction, under certain specified conditions. These correlations may also provide a test for distinguishing an electron from an atom transfer mechanism. (auth)

  12. Reduction of Large Detailed Chemical Kinetic Mechanisms for Autoignition Using Joint Analyses of Reaction Rates and Sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Saylam, A; Ribaucour, M; Pitz, W J; Minetti, R

    2006-11-29

    A new technique of reduction of detailed mechanisms for autoignition, which is based on two analysis methods is described. An analysis of reaction rates is coupled to an analysis of reaction sensitivity for the detection of redundant reactions. Thresholds associated with the two analyses have a great influence on the size and efficiency of the reduced mechanism. Rules of selection of the thresholds are defined. The reduction technique has been successfully applied to detailed autoignition mechanisms of two reference hydrocarbons: n-heptane and iso-octane. The efficiency of the technique and the ability of the reduced mechanisms to reproduce well the results generated by the full mechanism are discussed. A speedup of calculations by a factor of 5.9 for n-heptane mechanism and by a factor of 16.7 for iso-octane mechanism is obtained without losing accuracy of the prediction of autoignition delay times and concentrations of intermediate species.

  13. Formaldehyde assisted reduction achieved p-type orthorhombic tin oxide film prepared by an inexpensive chemical method

    Science.gov (United States)

    Sun, Jian; Chen, Zequn; Nie, Sha; Yu, Zhigen; Yan, Shenghui; Gong, Hao; Tang, Chunhua; Bai, Xue; Xu, Jianmei; Zhao, Ling; Zhou, Wei; Wang, Qing

    2017-11-01

    The fabrication of tin oxide thin film of orthorhombic phase has been succeeded under the high pressures from 1.5 GPa to 50 GPa. In this paper, we demonstrate the viability of p-type tin oxide thin film at atmosphere pressure of 0.1 MPa, by a chemical method employing formaldehyde (HCHO) during the annealing process. By using formaldehyde to form formaldehyde-argon mixed reducing ambiance in the chemical sol-gel process, limited oxidation is reached and p-type tin oxide films of orthorhombic phase under ambient pressure are eventually achieved under optimized experimental conditions. Specifically, we have developed a p-type tin oxide thin film with an optimal Hall mobility of 8.6 cm2 V‑1 s‑1. Besides, our results reveal that a Sn rich environment can lead to a higher hole mobility experimentally.

  14. Removal of Pathogens by Membrane Bioreactors: A Review of the Mechanisms, Influencing Factors and Reduction in Chemical Disinfectant Dosing

    Directory of Open Access Journals (Sweden)

    Faisal I. Hai

    2014-11-01

    Full Text Available The continued depletion of fresh drinking water resources throughout the world has increased the need for a variety of water treatment and recycling strategies. Conventional wastewater treatment processes rely on extensive chemical post-disinfection to comply with the stringent microbiological safety for water reuse. When well designed and operated, membrane bioreactors (MBRs can consistently achieve efficient removals of suspended solids, protozoa and coliform bacteria. Under optimal conditions, MBR systems can also significantly remove various viruses and phages. This paper provides an in-depth overview of the mechanisms and influencing factors of pathogen removal by MBR and highlights practical issues, such as reduced chemical disinfectant dosing requirements and associated economic and environmental benefits. Special attention has been paid to the aspects, such as membrane cleaning, membrane imperfections/breach and microbial regrowth, in the distribution system on the overall pathogen removal performance of MBR.

  15. Electrocatalytic Reduction of Nitrogen and Carbon Dioxide to Chemical Fuels: Challenges and Opportunities for a Solar Fuel Device.

    Science.gov (United States)

    Fenwick, Aidan Q; Gregoire, John M; Luca, Oana R

    2015-11-01

    Aspects of the electrochemical reduction of nitrogen and carbon dioxide at molecular and heterogeneous catalysts are discussed. We focus on recent advances in the field and touch on some of the remaining challenges in the production of solar fuels from N2 and CO2 with a direct, integrated solar fuel device. As such, we now propose metrics of catalyst assessment for non-H2 solar fuels. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Reduction and Oxidation Kinetics of a CaMn0.9Mg0.1O3-delta Oxygen Carrier for Chemical-Looping Combustion

    OpenAIRE

    Diego Poza, Luis F. de; Abad Secades, Alberto; Caballero Flores, Arturo; Gayán Sanz, Pilar; García-Labiano, Francisco; Adánez Elorza, Juan

    2014-01-01

    The objective of this study was to establish the reaction kinetics involved in redox cycles of the CaMn0.9Mg0.1O3−δ material to be used as an oxygen carrier in the chemical-looping-combustion process. The oxygen-transport capacity and reactivity of this material during consecutive reduction and oxidation steps with gaseous compounds (CH4, H2, CO, and O2) were studied in a thermogravimetric analysis apparatus. The oxygen uncoupling properties of this material were also analyzed. It was found t...

  17. Chemical Oxygen Demand (COD) For Monitoring Reduction-Oxidation (Redox) Equilibrium During High Level Waste (HLW) Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    JANTZEN, CAROLM.

    2004-04-30

    High-level nuclear waste is being immobilized at the Savannah River Site by vitrification into borosilicate glass at the Defense Waste Processing Facility. Control of the REDuction/OXidation (REDOX) equilibrium in the DWPF melter is critical for processing high level liquid wastes. Based upon previous research, an acceptable iron REDOX ratio was defined for the DWPF melts as 0.09 Fe2/SFe 0.33. Controlling the DWPF melter at a REDuction/OXidation (REDOX) equilibrium ofFe2/SFe 0.33 prevents the potential for metallic and metallic sulfide species to form and accumulate on the floor of the melter. Control of foaming due to deoxygenation of manganic species is achieved by converting 66-100 of the MnO2 or Mn2O3 species in a waste feed to MnO before the waste is fed to the DWPF melter. At the lower redox limit of Fe 2/SFe 0.09 about 99 of the Mn 4/Mn 3 is converted to Mn 2. Therefore, the lower REDOX limit eliminates melter foaming from deoxygenation. Organic and nitrate concentrations in the DWPF melter feed are the major parameters influencing melt REDOX. Organics such as formates act as reductants while nitrates, nitrites, and manganic (Mn 4 and Mn 3) species act as oxidants. During melting, the REDOX of the melt pool cannot be measured. Therefore, the Fe 2/SFe ratio in the glass poured from the melter must be related to melter feed organic and oxidant concentrations to ensure production of a high quality glass without impacting production rate (e.g., from foaming) or melter life (e.g., from metal formation and accumulation).

  18. Flow processes in overexpanded chemical rocket nozzles. Part 3: Methods for the aimed flow separation and side load reduction

    Science.gov (United States)

    Schmucker, R. H.

    1983-01-01

    Methods aimed at reduction of overexpansion and side load resulting from asymmetric flow separation for rocket nozzles with a high opening ratio are described. The methods employ additional measures for nozzles with a fixed opening ratio. The flow separation can be controlled by several types of nozzle inserts, the properties of which are discussed. Side loads and overexpansion can be reduced by adapting the shape of the nozzle and taking other additional measures for controlled separation of the boundary layer, such as trip wires.

  19. pH effect on the synthesis of magnetite nanoparticles by the chemical reduction-precipitation method

    Directory of Open Access Journals (Sweden)

    Ângela L. Andrade

    2010-01-01

    Full Text Available This work aimed at putting in evidence the influence of the pH on the chemical nature and properties of the synthesized magnetic nanocomposites. Saturation magnetization measurements evidenced a marked difference of the magnetic behavior of samples, depending on the final pH of the solution after reaction. Magnetite and maghemite in different proportions were the main magnetic iron oxides actually identified. Synthesis with final pH between 9.7-10.6 produced nearly pure magnetite with little or no other associated iron oxide. Under other synthetic conditions, goethite also appears in proportions that depended upon the pH of the synthesis medium.

  20. Rapid chemical evolution of tropospheric volcanic emissions from Redoubt Volcano, Alaska, based on observations of ozone and halogen-containing gases

    Science.gov (United States)

    Werner, Cynthia A.; Kelly, Peter; Kern, Christoph; Roberts, T.J.; Aluppe, A.

    2013-01-01

    We report results from an observational and modeling study of reactive chemistry in the tropospheric plume emitted by Redoubt Volcano, Alaska. Our measurements include the first observations of Br and I degassing from an Alaskan volcano, the first study of O3 evolution in a volcanic plume, as well as the first detection of BrO in the plume of a passively degassing Alaskan volcano. This study also represents the first detailed spatially-resolved comparison of measured and modeled O3 depletion in a volcanic plume. The composition of the plume was measured on June 20, 2010 using base-treated filter packs (for F, Cl, Br, I, and S) at the crater rim and by an instrumented fixed-wing aircraft on June 21 and August 19, 2010. The aircraft was used to track the chemical evolution of the plume up to ~ 30 km downwind (2 h plume travel time) from the volcano and was equipped to make in situ observations of O3, water vapor, CO2, SO2, and H2S during both flights plus remote spectroscopic observations of SO2 and BrO on the August 19th flight. The airborne data from June 21 reveal rapid chemical O3 destruction in the plume as well as the strong influence chemical heterogeneity in background air had on plume composition. Spectroscopic retrievals from airborne traverses made under the plume on August 19 show that BrO was present ~ 6 km downwind (20 min plume travel time) and in situ measurements revealed several ppbv of O3 loss near the center of the plume at a similar location downwind. Simulations with the PlumeChem model reproduce the timing and magnitude of the observed O3 deficits and suggest that autocatalytic release of reactive bromine and in-plume formation of BrO were primarily responsible for the observed O3 destruction in the plume. The measurements are therefore in general agreement with recent model studies of reactive halogen formation in volcanic plumes, but also show that field studies must pay close attention to variations in the composition of

  1. Preparation of nitrogen-doped graphene sheets by a combined chemical and hydrothermal reduction of graphene oxide.

    Science.gov (United States)

    Long, Donghui; Li, Wei; Ling, Licheng; Miyawaki, Jin; Mochida, Isao; Yoon, Seong-Ho

    2010-10-19

    Nitrogen-doped graphene sheets were prepared through a hydrothermal reduction of colloidal dispersions of graphite oxide in the presence of hydrazine and ammonia at pH of 10. The effect of hydrothermal temperature on the structure, morphology, and surface chemistry of as-prepared graphene sheets were investigated though XRD, N(2) adsorption, solid-state (13)C NMR, SEM, TEM, and XPS characterizations. Oxygen reduction and nitrogen doping were achieved simultaneously under the hydrothermal reaction. Up to 5% nitrogen-doped graphene sheets with slightly wrinkled and folded feature were obtained at the relative low hydrothermal temperature. With the increase of hydrothermal temperature, the nitrogen content decreased slightly and more pyridinic N incorporated into the graphene network. Meanwhile, a jellyfish-like graphene structure was formed by self-organization of graphene sheets at the hydrothermal temperature of 160 °C. Further increase of the temperature to 200 °C, graphene sheets could self-aggregate into agglomerate particles but still contained doping level of 4 wt % N. The unique hydrothermal environment should play an important role in the nitrogen doping and the jellyfish-like graphene formation. This simple hydrothermal method could provide the synthesis of nitrogen-doped graphene sheets in large scale for various practical applications.

  2. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid (OA) and sodium iodide (NaI). It is demonstrated that the combination of a reducing acid, OA, and NaI is indispensable for effective reduction of GO in the current study and this unique combination (1) allows for tunable control over the volume of the thus-prepared graphene assemblies and (2) enables 3D graphene assemblies to be prepared from the GO suspension with a wide range of concentrations (0.1 to 4.5 mg mL-1). To the best of our knowledge, the GO concentration of 0.1 mg mL-1 is the lowest GO concentration ever reported for preparation of 3D graphene assemblies. The thus-prepared 3D graphene assemblies exhibit low density, highly porous structures, and electrically conducting properties. As a proof of concept, we show that by infiltrating a responsive polymer of polydimethylsiloxane (PDMS) into the as-resulted 3D conducting network of graphene, a conducting composite is obtained, which can be used as a sensing device for differentiating organic solvents with different polarity. © 2012 The Royal Society of Chemistry.

  3. Photoelectrocatalytic reduction of CO2 into chemicals using Pt-modified reduced graphene oxide combined with Pt-modified TiO2 nanotubes.

    Science.gov (United States)

    Cheng, Jun; Zhang, Meng; Wu, Gai; Wang, Xin; Zhou, Junhu; Cen, Kefa

    2014-06-17

    The photoelectrocatalytic (PEC) reduction of CO2 into high-value chemicals is beneficial in alleviating global warming and advancing a low-carbon economy. In this work, Pt-modified reduced graphene oxide (Pt-RGO) and Pt-modified TiO2 nanotubes (Pt-TNT) were combined as cathode and photoanode catalysts, respectively, to form a PEC reactor for converting CO2 into valuable chemicals. XRD, XPS, TEM, AFM, and SEM were employed to characterize the microstructures of the Pt-RGO and Pt-TNT catalysts. Reduction products, such as C2H5OH and CH3COOH, were obtained from CO2 under band gap illumination and biased voltage. A combined liquid product generation rate (CH3OH, C2H5OH, HCOOH, and CH3COOH) of approximately 600 nmol/(h·cm(2)) was observed. Carbon atom conversion rate reached 1,130 nmol/(h·cm(2)), which were much higher than those achieved using Pt-modified carbon nanotubes and platinum carbon as cathode catalysts.

  4. Capacity of a newly isolated fungus Pleurotus eryngii from Tunceli, Ovacik for chemical oxygen demand reduction and biodecolorization of Azo-Dye Congo Red.

    Science.gov (United States)

    Yildirim, N; Gonen, U

    2015-06-07

    Biodecolorization of Congo red dye in both agar—plate and agitated liquid culture mediums by newly isolated white rot fungus Pleurotus eryngii has been studied. This fungus isolated from Tunceli—Ovacik province of Turkey. We have also examined the chemical oxygen demand reduction after decolorization under agitated liquid culture medium. For agar plate screening the decolorization capacity of P. eryngii, growth and decolorization halos were determined on saboroud dextrose agar (SDA) plates containing 0.05, 0.1, 0.5, 1 and 2 g/l of Congo red. P. eryngii showed certain decolorization capacities and was able to decolorize all studied concentrations of Congo red, but not to the same extent. Our results indicated that the new isolate P. eryngii had maximum decolorization (87% at 100 mg/l initial dye concentration) and chemical oxygen demand reduction (82% at 25 mg/l initial dye concentration) activities after 7 days under agitated submerged culture conditions. This new isolate could be an effective bioremediation tool for treatment of Congo red containing textile wastewater.

  5. Flexible graphene/carbon nanotube hybrid papers chemical-reduction-tailored by gallic acid for high-performance electrochemical capacitive energy storages

    Science.gov (United States)

    Yao, Lu; Zhou, Chao; Hu, Nantao; Hu, Jing; Hong, Min; Zhang, Liying; Zhang, Yafei

    2018-03-01

    Mechanically robust graphene papers with both high gravimetric and volumetric capacitances are desired for high-performance energy storages. However, it's still a challenge to tailor the structure of graphene papers in order to meet this requirement. In this work, a kind of chemical-reduction-tailored mechanically-robust reduced graphene oxide/carbon nanotube hybrid paper has been reported for high-performance electrochemical capacitive energy storages. Gallic acid (GA), as an excellent reducing agent, was used to reduce graphene oxide. Through vacuum filtration of gallic acid reduced graphene oxide (GA-rGO) and carboxylic multiwalled carbon nanotubes (MWCNTs) aqueous suspensions, mechanically robust GA-rGO/MWCNTs hybrid papers were obtained. The resultant hybrid papers showed high gravimetric capacitance of 337.6 F g-1 (0.5 A g-1) and volumetric capacitance of 151.2 F cm-3 (0.25 A cm-3). In addition, the assembled symmetric device based on the hybrid papers exhibited high gravimetric capacitance of 291.6 F g-1 (0.5 A g-1) and volumetric capacitance of 136.6 F cm-3 (0.25 A cm-3). Meanwhile, it exhibited excellent rate capability and cycling stability. Above all, this chemical reduction tailoring technique and the resultant high-performance GA-rGO/MWCNTs hybrid papers give an insight for designing high-performance electrodes and hold a great potential in the field of energy storages.

  6. Rapid and sensitive serum glucose determination using chemical labeling coupled with black phosphorus-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Qing; Yu, Lei; Qi, Chu-Bo; Ding, Jun; He, Xiao-Mei; Wang, Ren-Qi; Feng, Yu-Qi

    2018-01-01

    Monitoring the concentration of blood glucose in patients is a key component of good medical diagnoses. Therefore, developing an accurate, rapid and sensitive strategy for monitoring blood glucose is of vital importance. We proposed a strategy for serum glucose determination combining 2-(4-boronobenzyl) isoquinolin-2-ium bromide chemical labeling with black phosphorus assisted laser desorption ionization-time of flight mass spectrometry (CL-BP/ALDI-TOF MS). The entire analytical process consisted of 1min of protein precipitation and 3min of chemical labeling in a microwave oven prior to the BP/ALDI-TOF MS analysis. The analysis can be completed in 5min with high throughput and extremely low sample consumption. Good linearity for glucose was obtained with a correlation coefficient (R) of 0.9986. The limit of detection (LOD) and limit of quantification (LOQ) were 11.5 fmol and 37.5 fmol, respectively. Satisfied reproducibility and reliability were gained by evaluation of the intra- and inter-day precisions with relative standard deviations (RSDs) less than 7.2% and relative recoveries ranging from 87.1% to 108.1%, respectively. The proposed strategy was also applied for the analysis of endogenous glucose in various serum samples and the results were consistent with those obtained using the hexokinase method in a clinical laboratory. Considering the results, the proposed CL-BP/ALDI-TOF MS strategy has proven to be reliable, fast, and sensitive for quantitative analysis of serum glucose. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Chemical oxygen demand, total organic carbon and colour reduction in slaughterhouse wastewater by unmodified and iron-modified clinoptilolite-rich tuff.

    Science.gov (United States)

    Torres-Pérez, J; Solache-Ríos, M; Martínez-Miranda, V

    2014-01-01

    In this study, reduction of chemical oxygen demand (COD), colour, and total organic carbon in effluents from a slaughterhouse in central Mexico was performed using clinoptilolite-rich tuff. The experimental parameters considered were initial concentration of the adsorbate, pH, adsorbent dosage, and contact time. Surface morphology of the materials was tested by using scanning electron microscopy. Specific surface area was analysed by using Brunauer-Emmett-Teller (BET) and phase composition was analysed by using X-ray diffraction. The experimental adsorption data were fitted to the first- and pseudo-second-order kinetic models. The highest COD removal was observed in slightly acidic pH conditions. The maximum reduction efficiency of COD was accomplished with unmodified clinoptilolite-rich tuff at a contact time of 1440 min. In these conditions, the adsorbent was efficient for treating wastewater from a slaughterhouse. Moreover, after several regeneration cycles with Fenton reagent or hydrogen peroxide, the regenerated zeolite with H2O2 (3%) showed the best reduction efficiencies.

  8. Scan time reduction in {sup 23}Na-Magnetic Resonance Imaging using the chemical shift imaging sequence. Evaluation of an iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Weingaertner, Sebastian; Konstandin, Simon; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Wetterling, Friedrich [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Dublin Univ. (Ireland) Trinity Inst. of Neuroscience; Fatar, Marc [Heidelberg Univ., Mannheim (Germany). Dept. of Neurology; Neumaier-Probst, Eva [Heidelberg Univ., Mannheim (Germany). Dept. of Neuroradiology

    2015-07-01

    To evaluate potential scan time reduction in {sup 23}Na-Magnetic Resonance Imaging with the chemical shift imaging sequence (CSI) using undersampled data of high-quality datasets, reconstructed with an iterative constrained reconstruction, compared to reduced resolution or reduced signal-to-noise ratio. CSI {sup 23}Na-images were retrospectively undersampled and reconstructed with a constrained reconstruction scheme. The results were compared to conventional methods of scan time reduction. The constrained reconstruction scheme used a phase constraint and a finite object support, which was extracted from a spatially registered {sup 1}H-image acquired with a double-tuned coil. The methods were evaluated using numerical simulations, phantom images and in-vivo images of a healthy volunteer and a patient who suffered from cerebral ischemic stroke. The constrained reconstruction scheme showed improved image quality compared to a decreased number of averages, images with decreased resolution or circular undersampling with weighted averaging for any undersampling factor. Brain images of a stroke patient, which were reconstructed from three-fold undersampled k-space data, resulted in only minor differences from the original image (normalized root means square error < 12%) and an almost identical delineation of the stroke region (mismatch < 6%). The acquisition of undersampled {sup 23}Na-CSI images enables up to three-fold scan time reduction with improved image quality compared to conventional methods of scan time saving.

  9. Effects of the gas feeding method on the properties of 3C-SiC/Si(111) grown by rapid thermal chemical vapor deposition

    CERN Document Server

    Shim, H W; Suh, E K

    1998-01-01

    High-quality crystalline 3C-SiC thin films are grown by rapid thermal chemical vapor deposition (RTCVD) on Si(111) by using two different growth processes. The films are grown along the [111] direction at 1200 .deg. C. The quality of the films are investigated by X-ray diffraction, transmission electron microscopy, and transmission electron diffraction. The SiC film grown by flowing the tetramethylsilane (TMS) gas before heating the substrate up to the growth temperature does not contain many voids at the SiC/Si interface, while the SiC grown by heating the substrate before supplying the TMS gas possesses many voids at the interface. The unintentionally doped SiC film grown by gas flow before heating the substrate appears to be n-type with a carrier concentration of 1.48 x 10 sup 1 sup 6 cm sup - sup 3 , a electron mobility of 884 cm sup 2 /V centre dot s, and a resistivity of 0.462 OMEGA centre dot cm. The physical properties, such as the electrical properties, the surface morphology, and the crystallinity, ...

  10. Assessment of the reduction methods used to develop chemical schemes: building of a new chemical scheme for VOC oxidation suited to three-dimensional multiscale HOx-NOx-VOC chemistry simulations

    Directory of Open Access Journals (Sweden)

    S. Szopa

    2005-01-01

    Full Text Available The objective of this work was to develop and assess an automatic procedure to generate reduced chemical schemes for the atmospheric photooxidation of volatile organic carbon (VOC compounds. The procedure is based on (i the development of a tool for writing the fully explicit schemes for VOC oxidation (see companion paper Aumont et al., 2005, (ii the application of several commonly used reduction methods to the fully explicit scheme, and (iii the assessment of resulting errors based on direct comparison between the reduced and full schemes. The reference scheme included seventy emitted VOCs chosen to be representative of both anthropogenic and biogenic emissions, and their atmospheric degradation chemistry required more than two million reactions among 350000 species. Three methods were applied to reduce the size of the reference chemical scheme: (i use of operators, based on the redundancy of the reaction sequences involved in the VOC oxidation, (ii grouping of primary species having similar reactivities into surrogate species and (iii grouping of some secondary products into surrogate species. The number of species in the final reduced scheme is 147, this being small enough for practical inclusion in current three-dimensional models. Comparisons between the fully explicit and reduced schemes, carried out with a box model for several typical tropospheric conditions, showed that the reduced chemical scheme accurately predicts ozone concentrations and some other aspects of oxidant chemistry for both polluted and clean tropospheric conditions.

  11. Chemical reduction of the elastic properties of zeolites: a comparison of the formation of carbonate species versus dealumination.

    Science.gov (United States)

    Bryukhanov, I A; Rybakov, A A; Kovalev, V L; Larin, A V; Zhidomirov, G M

    2015-02-14

    The decrease in elastic moduli (Young's, bulk, and shear modulus), the variations in their asymmetries, the Poisson's ratio and the linear compressibility due to carbonate formation in NaX, have been compared to those produced by dealumination of the zeolite HY framework, from the Al-Si-Al fragment positioned in joined 4R rings. All these systems have been considered at the density functional theory (DFT) level using periodic boundary conditions. The representativeness of the models has been checked by comparison of the calculated IR spectra of carbonate and hydrocarbonate species in NaX and of hydroxyl groups in HY with the experimental equivalents. The correlation between the destabilization energy of the systems and the displacement of Na or K cations coordinated to the carbonate or hydrocarbonate species, expressed in terms of Me-O bond elongation, has been confirmed for either one or two carbonate and hydrocarbonate species per unit cell (UC). Finally, a similar reduction in elasticity in FAU zeolites has been observed, due either to carbonate/bicarbonate formation in NaX or as a step in HY dealumination.

  12. During Rapid Weight Loss in Obese Children, Reductions in TSH Predict Improvements in Insulin Sensitivity Independent of Changes in Body Weight or Fat

    NARCIS (Netherlands)

    Aeberli, I.; Jung, A.; Murer, S.B.; Wildhaber, J.; Wildhaber-Brooks, J.; Knopfli, B.H.; Zimmermann, M.B.

    2010-01-01

    Background: Although serum TSH is often elevated in obesity and may be linked to disorders of lipid and glucose metabolism, the clinical relevance of these relationships remains unclear. Subjects: Subjects were obese children and adolescents (n = 206; mean age 14 yr) undergoing rapid weight and fat

  13. Metal Artifact Reduction: Added Value of Rapid-Kilovoltage-Switching Dual-Energy CT in Relation to Single-Energy CT in a Piglet Animal Model.

    Science.gov (United States)

    Takrouri, Heba S; Alnassar, Mutaz M; Amirabadi, Afsaneh; Babyn, Paul S; Moineddin, Rahim; Padfield, Nancy L; BenDavid, Guila; Doria, Andrea S

    2015-09-01

    The purpose of this article is to evaluate virtual monochromatic spectral imaging and metal artifact reduction software for reducing metal artifact and to compare it with conventional single-energy CT (SECT) in an animal model. Postmortem juvenile (n = 5) and adult (n = 1) swine specimens were scanned with SECT followed by a dual-energy CT (DECT) pediatric protocol after the insertion of two rods into their paraspinal thoracolumbar regions. Virtual monochromatic spectral images were extrapolated from DECT images at five monoenergetic levels (64, 69, 75, 88, and 105 keV) with and without the use of metal artifact reduction software. Images were evaluated by a 5-point scoring system for the extent of metallic artifacts and image interpretability in soft-tissue and bone windows. The density in the most pronounced artifact was measured. CT dose index was recorded. In studies without metal artifact reduction software, higher energy reconstructions resulted in fewer artifacts and better image interpretability in both soft-tissue and bone windows (p 0.05). DECT studies showed lower scores compared with SECT with regard to all attributes. A new faint perimetallic hypodense halo was seen in all studies with metal artifact reduction software. The CT dose index of DECT was 1.18-3.56 times higher than that of SECT techniques. DECT at all energy levels with metal artifact reduction software and higher energy extrapolations without metal artifact reduction software reduced metallic artifact and enhanced image interpretability compared with SECT. Radiation dose with DECT could be significantly higher than SECT.

  14. Electric and Magnetic Fields (EMF) RAPID Program Engineering Project 8: FINAL REPORT, Evaluation of Field Reduction Technologies, Volume 1 (Report) and Volume 2 (Appendices)

    Energy Technology Data Exchange (ETDEWEB)

    Commonwealth Associates, Inc.; IIT Research Institute

    1997-08-01

    This draft report consists of two volumes. Volume 1, the main body, contains an introducto~ sectionj an overview of magnetic fields sectio~ and field reduction technology evaluation section. Magnetic field reduction methods are evalpated for transmission lines, distribution Iines,sulxtations, building wiring applkmd machinery, and transportation systems. The evaluation considers effectiveness, co% and other ftiors. Volume 2 contains five appendices, Append~ A presents magnetic field shielding information. Appendices B and C present design assumptions and magnetic field plots for transmission and distribution lines, respectively. Appendices D and E present cost estimate details for transmission and distribution limes, respectively.

  15. Development and Application of Computational/In Vitro Toxicological Methods for Chemical Hazard Risk Reduction of New Materials for Advanced Weapon Systems

    Science.gov (United States)

    Frazier, John M.; Mattie, D. R.; Hussain, Saber; Pachter, Ruth; Boatz, Jerry; Hawkins, T. W.

    2000-01-01

    The development of quantitative structure-activity relationship (QSAR) is essential for reducing the chemical hazards of new weapon systems. The current collaboration between HEST (toxicology research and testing), MLPJ (computational chemistry) and PRS (computational chemistry, new propellant synthesis) is focusing R&D efforts on basic research goals that will rapidly transition to useful products for propellant development. Computational methods are being investigated that will assist in forecasting cellular toxicological end-points. Models developed from these chemical structure-toxicity relationships are useful for the prediction of the toxicological endpoints of new related compounds. Research is focusing on the evaluation tools to be used for the discovery of such relationships and the development of models of the mechanisms of action. Combinations of computational chemistry techniques, in vitro toxicity methods, and statistical correlations, will be employed to develop and explore potential predictive relationships; results for series of molecular systems that demonstrate the viability of this approach are reported. A number of hydrazine salts have been synthesized for evaluation. Computational chemistry methods are being used to elucidate the mechanism of action of these salts. Toxicity endpoints such as viability (LDH) and changes in enzyme activity (glutahoione peroxidase and catalase) are being experimentally measured as indicators of cellular damage. Extrapolation from computational/in vitro studies to human toxicity, is the ultimate goal. The product of this program will be a predictive tool to assist in the development of new, less toxic propellants.

  16. Experimental reduction of lunar mare soil and volcanic glass

    Science.gov (United States)

    Allen, Carlton C.; Morris, Richard V.; Mckay, David S.

    1994-01-01

    We have reduced high-titanium lunar mare soil and iron-rich lunar volcanic glass with hydrogen at temperatures of 900-1100 C. Ilmenite is the most reactive phase in the soil, exhibiting rapid and complete reduction at all temperatures. Ferrous iron in the glass is extensively reduced concurrent with partial crystallization. In both samples pyroxene and olivine undergo partial reduction along with chemical and mineralogical modifications. High-temperature reduction provides insight into the optical and chemical effects of lunar soil maturation, and places constraints on models of that process. Mare soil and volcanic glass are attractive feedstocks for lunar oxygen production, with achievable yields of 2-5 wt%.

  17. A controlled study of the effect of a mindfulness-based stress reduction technique in women with multiple chemical sensitivity, chronic fatigue syndrome, and fibromyalgia

    Science.gov (United States)

    Sampalli, Tara; Berlasso, Elizabeth; Fox, Roy; Petter, Mark

    2009-01-01

    Background: The objective of this study was to examine the effect of a mindfulness-based stress reduction (MBSR) program on women diagnosed with conditions such as multiple chemical sensitivity (MCS), chronic fatigue syndrome (CFS), and fibromyalgia (FM). Methods: The intervention group underwent a 10-week MBSR program. Symptoms Checklist Inventory (SCL-90R) was used as outcome measure and was administered before the start of the program (pre-), immediately upon completion (post-) and at three-month follow-up. Women on the wait list to receive treatment at the Nova Scotia Environmental Health Centre were used as control subjects for the study. Results: A total of 50 participants in the intervention group and 26 in the wait-list controls group were recruited for this study. Global scores in the intervention group reached statistical significance pre-post (<0.0001) and at pre-follow-up (<0.0001) while the global scores in the control group remained the same. Five of nine and eight of nine subscales of the SCL-90R showed improvement of statistical significance in MBSR group following treatment and at three-month follow-up. Conclusions: The study showed the importance of complementary interventions such as MBSR techniques in the reduction of psychological distress in women with chronic conditions. PMID:21197347

  18. Chemical-free fabrication of N, P dual-doped honeycomb-like carbon as an efficient electrocatalyst for oxygen reduction.

    Science.gov (United States)

    Zhu, Lianwen; Wu, Jun; Zhang, Qiao; Li, Xiangkui; Li, Yiming; Cao, Xuebo

    2018-01-15

    Heteroatom-doped nanoporous carbons are now emerging as alternatives to platinum and its alloys as electrocatalysts to facilitate oxygen reduction reaction in metal-air batteries and fuel cells. However, the synthesis of nanoporous carbons usually involve in complicated procedures and intensive chemicals, which may dramatically raise their manufacture cost that even surpasses that of precious platinum. Herein, we demonstrate the single-step, chemical-free fabrication of N, P dualdoped honeycomb carbon that has hierarchically porous structure and oxygen electrocatalysis activity close to the benchmark Pt/C. This material was fabricated through the direct pyrolysis of popcorn in a static, semi-opened environment. With this strategy, nitrous and phosphoric groups from proteins and phosphates within the popcorn are condensed with graphitic matrix to form NC and PC bonds, and pyrolysis byproducts (such as H2O and CO2) can etch disordered carbon domains to form hierarchical pores and edge carbons. Practical test of this honeycomb carbon as air electrode of a primary Zn-air battery shows an open-circuit potential of 1.44V and peak power density of 36.6mWcm-2 that is even better than Pt/C. The impact of this work is that it will facilitate the targeted design and cost-saved fabrication of metal-free catalysts for electrocatalytic applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. A Split-Face Evaluation to Assess the Efficacy of a Hydrolyzed Roe Cream in the Reduction of Erythema Following Chemical Peel

    Science.gov (United States)

    Narurkar, Vic A.

    2016-01-01

    Objective:To evaluate a hydrolyzed roe cream in the reduction of facial erythema following a chemical peel treatment. Edema was also assessed. Design:The facial cream was applied to one side of the face of 30 healthy female subjects (average age = 54.9 years, range 33–65 years) immediately following 4 to 15 minutes peel treatment. The opposite side remained untreated. Visia-CR digital photographs were taken at baseline and 8 and 24 hours post facial peel. Objective dermal irritation assessments were done by a blinded investigator, graded on severity of facial erythema and edema on a 5-point scoring scale; 0=none, 1 =slight,2=mild, 3=moderate, 4=severe. Subjects completed a perception questionnaire. Results: Reduction in erythema was greater (P≤0.05) for the treated side of the face compared to the untreated side at both 8 and 24 hours post-peel. Both sides showed reduction in erythema compared to immediate post-peel. No edema was observed. At eight hours, more than 50 percent of subjects agreed on the five attributes, and at 24 hours, 57 percent (17/30) of subjects agreed. At eight hours, ≥80 percent of subjects strongly agreed or agreed that the treated skin feels hydrated and moisturized immediately after application. At 24 hours, more than 90 percent of subjects strongly agreed or agreed that treated skin feels perfectly hydrated and moisturized. When asked about their overall impression of the product, 60 percent (18 subjects) of subjects responded”! love it.”All subjects completed the study. No adverse events were reported. Conclusion: Applying the facial lotion directly on post-procedure skin reduces redness after 8 and 24 hours significantly better compared to no treatment. PMID:27847550

  20. Kinetics of the reduction of hematite (Fe{sub 2}O{sub 3}) by methane (CH{sub 4}) during chemical looping combustion: A global mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Monazam, Esmail R; Breault, Ronald W; Siriwardane, Ranjani; Richards, George; Carpenter, Stephen

    2013-10-01

    Chemical-looping combustion (CLC) has emerged as a promising technology for fossil fuel combustion which produces a sequestration ready concentrated CO{sub 2} stream in power production. A CLC system is composed with two reactors, an air and a fuel reactor. An oxygen carrier such as hematite (94%Fe{sub 2}O{sub 3}) circulates between the reactors, which transfers the oxygen necessary for the fuel combustion from the air to the fuel. An important issue for the CLC process is the selection of metal oxide as oxygen carrier, since it must retain its reactivity through many cycles. The primary objective of this work is to develop a global mechanism with respective kinetics rate parameters such that CFD simulations can be performed for large systems. In this study, thermogravimetric analysis (TGA) of the reduction of hematite (Fe{sub 2}O{sub 3}) in a continuous stream of CH{sub 4} (15, 20, and 35%) was conducted at temperatures ranging from 700 to 825{degrees}C over ten reduction cycles. The mass spectroscopy analysis of product gas indicated the presence of CO{sub 2} and H{sub 2}O at the early stage of reaction and H{sub 2} and CO at the final stage of reactions. A kinetic model based on two parallel reactions, 1) first-order irreversible rate kinetics and 2) Avrami equation describing nucleation and growth processes, was applied to the reduction data. It was found, that the reaction rates for both reactions increase with, both, temperature and the methane concentration in inlet gas.

  1. Kinetic studies of peroxiredoxin 6 from Arenicola marina: rapid oxidation by hydrogen peroxide and peroxynitrite but lack of reduction by hydrogen sulfide.

    Science.gov (United States)

    Loumaye, Eléonore; Ferrer-Sueta, Gerardo; Alvarez, Beatriz; Rees, Jean-François; Clippe, André; Knoops, Bernard; Radi, Rafael; Trujillo, Madia

    2011-10-01

    Arenicola marina lives in marine environments where hydrogen peroxide concentrations reach micromolar levels. The annelid also forms reactive species through metabolic pathways. Its antioxidant systems include a cytosolic peroxiredoxin, peroxiredoxin 6 (AmPrx6 or AmPRDX6) that shows high homology to the mammalian 1-Cys peroxiredoxin. Previous work confirmed the peroxidase activity of AmPrx6 in the presence of dithiotreitol. Herein, we performed an in vitro kinetic characterization of the recombinant enzyme. AmPrx6 reduced hydrogen peroxide and peroxynitrite with rate constants of 1.1×10(7) and 2×10(6)M(-1)s(-1), respectively, at pH 7.4 and 25°C. Reduction of tert-butyl hydroperoxide was slower. The pK(a) of the peroxidatic thiol of AmPrx6 was determined as 5.1±0.2, indicating that it exists as thiolate, the reactive species, at physiological pH. The reductive part of the catalytic cycle was also explored. Hydrogen sulfide, present in millimolar concentrations in marine sediments where the annelid lives and that is able to reduce the mammalian 1-Cys peroxiredoxin, did not support AmPrx6 peroxidase activity. The enzyme was not reduced by other potential physiological reductants tested. Our data indicate that in this annelid, Prx6 could contribute to peroxide detoxification in the presence of a so far unidentified reducing counterpart. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Electrochemical properties of nano-cobalt powder prepared by chemical reduction with and without cetyltrimethylammonium bromide and carbon-coated at 500 °C for secondary lithium Batteries

    Science.gov (United States)

    Hong, Seong-Hyeon; Jin, Yeong-Mi; Song, Myoung Youp

    2014-07-01

    X-ray diffraction patterns show that Co-based powders prepared by chemical reduction with and without Cetyltrimethylammonium bromide (CTAB, C19H42BrN) and carbon-coated at 500°C are not crystallized and amorphous-like as they are just after the chemical reduction. The Co-based powder prepared by chemical reduction with CTAB has carbon-coated layers with thicknesses of 15-20 nm. Comparing the 20% carbon-added powders, the powder prepared by chemical reduction with CTAB and carbon-coated at 500 °C has a larger first discharge capacity (about 1,230 mAh g-1) than the powder prepared by chemical reduction without CTAB and carbon-coated at 500 °C (about 902 mAh g-1). The reason is believed to be that the carbon layer obstructs the expansion of the Co phase and the formation of the solid electrolyte interface on the surface of the Co. Comparing the powders that are carbon-coated with CTAB added, the 20% carbon-added powder has a larger first discharge capacity (about 1,230 mAh g-1) than the 10% carbon-added powder (about 1,130 mAh g-1).

  3. Novel route for rapid sol-gel synthesis of hydroxyapatite, avoiding ageing and using fast drying with a 50-fold to 200-fold reduction in process time.

    Science.gov (United States)

    Ben-Arfa, Basam A E; Salvado, Isabel M Miranda; Ferreira, José M F; Pullar, Robert C

    2017-01-01

    We have developed an innovative, rapid sol-gel method of producing hydroxyapatite nanopowders that avoids the conventional lengthy ageing and drying processes (over a week), being 200 times quicker in comparison to conventional aqueous sol-gel preparation, and 50 times quicker than ethanol based sol-gel synthesis. Two different sets of experimental conditions, in terms of pH value (5.5 and 7.5), synthesis temperature (45 and 90°C), drying temperature (60 and 80°C) and calcination temperature (400 and 700°C) were explored. The products were characterised by X-ray diffraction (XRD) Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and specific surface area (SSA) measurements. Pure hydroxyapatite (Ca10(PO4)6(OH)2, HAp) was obtained for the powders synthesised at pH7.5 and calcined at 400°C, while biphasic mixtures of HAp/β-tricalcium phosphate (β-Ca3(PO4)2, TCP) were produced at pH5.5 and (pH7.5 at elevated temperature). The novel rapid drying was up to 200 times faster than conventional drying, only needing 1h with no prior ageing step, and favoured the formation of smaller/finer nanopowders, while producing pure HAp or phase mixtures virtually identical to those obtained from the slow conventional drying method, despite the absence of a slow ageing process. The products of this novel rapid process were actually shown to have smaller crystallite sizes and larger SSA, which should result in increased bioactivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Combining a Clostridial enzyme exhibiting unusual active site plasticity with a remarkably facile sigmatropic rearrangement: rapid, stereocontrolled entry into densely functionalized fluorinated phosphonates for chemical biology.

    Science.gov (United States)

    Panigrahi, Kaushik; Applegate, Gregory A; Malik, Guillaume; Berkowitz, David B

    2015-03-18

    Described is an efficient stereocontrolled route into valuable, densely functionalized fluorinated phosphonates that takes advantage of (i) a Clostridial enzyme to set the absolute stereochemistry and (ii) a new [3,3]-sigmatropic rearrangement of the thiono-Claisen variety that is among the fastest sigmatropic rearrangements yet reported. Here, a pronounced rate enhancement is achieved by distal fluorination. This rearrangement is completely stereoretentive, parlaying the enzymatically established β-C-O stereochemistry in the substrate into the δ-C-S stereochemistry in the product. The final products are of interest to chemical biology, with a platform for Zn-aminopeptidase A inhibitors being constructed here. The enzyme, Clostridium acetobutylicum (CaADH), recently expressed by our group, reduces a spectrum of γ,δ-unsaturated β-keto-α,α-difluorophosphonate esters (93-99% ee; 10 examples). The resultant β-hydroxy-α,α-difluorophosphonates possess the "L"-stereochemistry, opposite to that previously observed for the CaADH-reduction of ω-keto carboxylate esters ("D"), indicating an unusual active site plasticity. For the thiono-Claisen rearrangement, a notable structure-reactivity relationship is observed. Measured rate constants vary by over 3 orders of magnitude, depending upon thiono-ester structure. Temperature-dependent kinetics reveal an unusually favorable entropy of activation (ΔS(‡) = 14.5 ± 0.6 e.u.). Most notably, a 400-fold rate enhancement is seen upon fluorination of the distal arene ring, arising from favorable enthalpic (ΔΔH(‡) = -2.3 kcal/mol) and entropic (ΔΔS(‡) = 4 e.u., i.e. 1.2 kcal/mol at rt) contributions. The unusual active site plasticity seen here is expected to drive structural biology studies on CaADH, while the exceptionally facile sigmatropic rearrangement is expected to drive computational studies to elucidate its underlying entropic and enthalpic basis.

  5. Rapid total sulphur reduction in coal samples using various dilute alkaline leaching reagents under microwave heating: preventing sulphur emissions during coal processing.

    Science.gov (United States)

    Mketo, Nomvano; Nomngongo, Philiswa Nosizo; Ngila, Jane Catherine

    2017-08-01

    Currently in South Africa, online flue gas desulphurisation (FGD) is being utilized as one of the most effective methods for total sulphur reduction in coal samples during the combustion process. However, the main disadvantage associated with FGD is the formation of its by-products (FGD gypsum). The latter is mostly formed in low grade quality, thereby bringing secondary pollution problems and extra disposal costs. Therefore, the current study describes the development of total sulphur extraction in coal under microwave heating using different dilute alkaline solutions such as NaOH, NaOH-H2O2, NH4OH, and NH4OH-H2O2. The experimental conditions were as follows: 150 °C, 5 min and 10% (m/v or v/v) for temperature, extraction time and reagent concentration, respectively. The most effective alkaline reagent for coal desulphurisation was observed to be NaOH-H2O2 with total sulphur reduction of 55% (from the inductively coupled plasma-optical emission spectrometry (ICP-OES) results). The NaOH-H2O2 reagent also showed significant morphological changes in coal as observed from the SEM images and effective demineralisation as revealed by the powder X-ray diffractometer (P-XRD) results. Additionally, desulphurisation results obtained from the developed microwave-assisted dilute alkaline extraction (MW-ADAE) method were quite comparable with the published work. The proposed total sulphur reduction method is advantageous as compared to some of the literature reported coal desulphurisation methods as it requires a short period (5 min) of time to reach its completion. Additionally, the proposed method shows excellent reproducibility (% RSD from 0.5 to 1); therefore, it can be utilized for routine analysis. Graphical abstract ᅟ.

  6. Development of an Activated Carbon-Based Electrode for the Capture and Rapid Electrolytic Reductive Debromination of Methyl Bromide from Postharvest Fumigations.

    Science.gov (United States)

    Li, Yuanqing; Liu, Chong; Cui, Yi; Walse, Spencer S; Olver, Ryan; Zilberman, David; Mitch, William A

    2016-10-18

    Due to concerns surrounding its ozone depletion potential, there is a need for technologies to capture and destroy methyl bromide (CH 3 Br) emissions from postharvest fumigations applied to control agricultural pests. Previously, we described a system in which CH 3 Br fumes vented from fumigation chambers could be captured by granular activated carbon (GAC). The GAC was converted to a cathode by submergence in a high ionic strength solution and connection to the electrical grid, resulting in reductive debromination of the sorbed CH 3 Br. The GAC bed was drained and dried for reuse to capture and destroy CH 3 Br fumes from the next fumigation. However, the loose GAC particles and slow kinetics of this primitive electrode necessitated improvements. Here, we report the development of a cathode containing a thin layer of small GAC particles coating carbon cloth as a current distributor. Combining the high sorption potential of GAC for CH 3 Br with the conductivity of the carbon cloth current distributor, the cathode significantly lowered the total cell resistance and achieved 96% reductive debromination of CH 3 Br sorbed at 30% by weight to the GAC within 15 h at -1 V applied potential vs standard hydrogen electrode, a time scale and efficiency suitable for postharvest fumigations. The cathode exhibited stable performance over 50 CH 3 Br capture and destruction cycles. Initial cost estimates indicate that this technique could treat CH 3 Br fumes at ∼$5/kg, roughly one-third of the cost of current alternatives.

  7. The rapid climate change-caused dichotomy on subtropical evergreen broad-leaved forest in Yunnan: Reduction in habitat diversity and increase in species diversity

    Directory of Open Access Journals (Sweden)

    Zhe Ren

    2016-06-01

    Full Text Available Yunnan's biodiversity is under considerable pressure and subtropical evergreen broad-leaved forests in this area have become increasingly fragmented through agriculture, logging, planting of economic plants, mining activities and changing environment. The aims of the study are to investigate climate change-induced changes of subtropical evergreen broad-leaved forests in Yunnan and identify areas of current species richness centers for conservation preparation. Stacked species distribution models were created to generate ensemble forecasting of species distributions, alpha diversity and beta diversity for Yunnan's subtropical evergreen broad-leaved forests in both current and future climate scenarios. Under stacked species distribution models in rapid climate changes scenarios, changes of water-energy dynamics may possibly reduce beta diversity and increase alpha diversity. This point provides insight for future conservation of evergreen broad-leaved forest in Yunnan, highlighting the need to fully consider the problem of vegetation homogenization caused by transformation of water-energy dynamics.

  8. Individualized dosimetry-based activity reduction of {sup 90}Y-DOTATOC prevents severe and rapid kidney function deterioration from peptide receptor radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Binnebeek, Sofie van; Baete, Kristof; Vanbilloen, Bert; Terwinghe, Christelle; Mortelmans, Luc [University Hospitals Leuven, Nuclear Medicine, Leuven (Belgium); KU Leuven, Department of Imaging and Pathology, Leuven (Belgium); Koole, Michel [University Medical Centre Groningen, Department of Nuclear Medicine, Groningen (Netherlands); Mottaghy, Felix M. [University Hospital Aachen, Department of Nuclear Medicine, Aachen (Germany); Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); Clement, Paul M. [University Hospitals Leuven, Medical Oncology, Leuven (Belgium); KU Leuven, Laboratory of Experimental Oncology, Leuven (Belgium); Haustermans, Karin [University Hospitals Leuven, Radiation Oncology, Leuven (Belgium); KU Leuven, Department of Oncology, Leuven (Belgium); Cutsem, Eric van; Verslype, Chris [KU Leuven, Department of Oncology, Leuven (Belgium); University Hospitals Leuven, Division of Digestive Oncology, Leuven (Belgium); Verbruggen, Alfons [KU Leuven, Laboratory for Radiopharmacy, Leuven (Belgium); Bogaerts, Kris [KU Leuven, Division of Public Health and Primary Care (I-Biostat), Leuven (Belgium); Deroose, Christophe M. [University Hospitals Leuven, Nuclear Medicine, Leuven (Belgium); KU Leuven, Department of Imaging and Pathology, Leuven (Belgium); UZ Leuven, Nuclear Medicine, Leuven (Belgium)

    2014-06-15

    Assessment of kidney function evolution after {sup 90}Y-DOTATOC peptide receptor radionuclide therapy (PRRT) with capped activity administration based on a 37-Gy threshold of biological effective dose (BED) to the kidney. In a prospective phase II study, patients with metastasized neuroendocrine tumours were evaluated for therapy using 185 MBq {sup 111}In-pentetreotide with amino acid coinfusion. Planar whole-body images were acquired at four time-points after injection and kidney volumes were measured using CT/MRI. BED to the kidneys was estimated using an extended BED formula and biexponential renal clearance. Based on published BED dose-toxicity relationships, we allowed a maximal kidney BED of 37 Gy; if the calculated BED exceeded 37 Gy, treatment activity was reduced accordingly. Kidney function was assessed at baseline and at 18 months, predominantly using {sup 51}Cr-EDTA. The rate of renal function decline was expressed as annual glomerular filtration rate loss (aGFRL). Only 22 of 50 patients reached the 18-months time-point, with most missing patients having died due to disease progression. In the 22 patients who reached 18 months, no rapid kidney function deterioration was observed over the 18 months, aGFRL >33 % was not seen, and only three patients showed an increase of one toxicity grade and one patient an increase of two grades. No significant correlations between kidney volume (p = 0.35), baseline GFR (p = 0.18), risk factors for renal function loss (p = 0.74) and aGFRL were observed. Among the 28 patients who did not reach 18 months, one developed grade 4 kidney toxicity at 15 months after PRRT. Prospective dosimetry using a 37 Gy BED as the threshold for kidney toxicity is a good guide for {sup 90}Y-DOTATOC PRRT and is associated with a low risk of rapid renal function deterioration and evolution to severe nephrotoxicity. (orig.)

  9. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng [Irvine, CA; Sui, Guodong [Los Angeles, CA; Elizarov, Arkadij [Valley Village, CA; Kolb, Hartmuth C [Playa del Rey, CA; Huang, Jiang [San Jose, CA; Heath, James R [South Pasadena, CA; Phelps, Michael E [Los Angeles, CA; Quake, Stephen R [Stanford, CA; Tseng, Hsian-rong [Los Angeles, CA; Wyatt, Paul [Tipperary, IE; Daridon, Antoine [Mont-Sur-Rolle, CH

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  10. Rapid decline in HCV incidence among people who inject drugs associated with national scale-up in coverage of a combination of harm reduction interventions.

    Science.gov (United States)

    Palmateer, Norah E; Taylor, Avril; Goldberg, David J; Munro, Alison; Aitken, Celia; Shepherd, Samantha J; McAllister, Georgina; Gunson, Rory; Hutchinson, Sharon J

    2014-01-01

    Government policy has precipitated recent changes in the provision of harm reduction interventions - injecting equipment provision (IEP) and opiate substitution therapy (OST) - for people who inject drugs (PWID) in Scotland. We sought to examine the potential impact of these changes on hepatitis C virus (HCV) transmission among PWID. We used a framework to triangulate different types of evidence: 'group-level/ecological' and 'individual-level'. Evidence was primarily generated from bio-behavioural cross-sectional surveys of PWID, undertaken during 2008-2012. Individuals in the window period (1-2 months) where the virus is present, but antibodies have not yet been formed, were considered to have recent infection. The survey data were supplemented with service data on the provision of injecting equipment and OST. Ecological analyses examined changes in intervention provision, self-reported intervention uptake, self-reported risk behaviour and HCV incidence; individual-level analyses investigated relationships within the pooled survey data. Nearly 8,000 PWID were recruited in the surveys. We observed a decline in HCV incidence, per 100 person-years, from 13.6 (95% CI: 8.1-20.1) in 2008-09 to 7.3 (3.0-12.9) in 2011-12; a period during which increases in the coverage of OST and IEP, and decreases in the frequency of injecting and sharing of injecting equipment, were observed. Individual-level evidence demonstrated that combined high coverage of needles/syringes and OST were associated with reduced risk of recent HCV in analyses that were unweighted (AOR 0.29, 95%CI 0.11-0.74) and weighted for frequency of injecting (AORw 0.05, 95%CI 0.01-0.18). We estimate the combination of harm reduction interventions may have averted 1400 new HCV infections during 2008-2012. This is the first study to demonstrate that impressive reductions in HCV incidence can be achieved among PWID over a relatively short time period through high coverage of a combination of interventions.

  11. Rapid decline in HCV incidence among people who inject drugs associated with national scale-up in coverage of a combination of harm reduction interventions.

    Directory of Open Access Journals (Sweden)

    Norah E Palmateer

    Full Text Available BACKGROUND: Government policy has precipitated recent changes in the provision of harm reduction interventions - injecting equipment provision (IEP and opiate substitution therapy (OST - for people who inject drugs (PWID in Scotland. We sought to examine the potential impact of these changes on hepatitis C virus (HCV transmission among PWID. METHODS AND FINDINGS: We used a framework to triangulate different types of evidence: 'group-level/ecological' and 'individual-level'. Evidence was primarily generated from bio-behavioural cross-sectional surveys of PWID, undertaken during 2008-2012. Individuals in the window period (1-2 months where the virus is present, but antibodies have not yet been formed, were considered to have recent infection. The survey data were supplemented with service data on the provision of injecting equipment and OST. Ecological analyses examined changes in intervention provision, self-reported intervention uptake, self-reported risk behaviour and HCV incidence; individual-level analyses investigated relationships within the pooled survey data. Nearly 8,000 PWID were recruited in the surveys. We observed a decline in HCV incidence, per 100 person-years, from 13.6 (95% CI: 8.1-20.1 in 2008-09 to 7.3 (3.0-12.9 in 2011-12; a period during which increases in the coverage of OST and IEP, and decreases in the frequency of injecting and sharing of injecting equipment, were observed. Individual-level evidence demonstrated that combined high coverage of needles/syringes and OST were associated with reduced risk of recent HCV in analyses that were unweighted (AOR 0.29, 95%CI 0.11-0.74 and weighted for frequency of injecting (AORw 0.05, 95%CI 0.01-0.18. We estimate the combination of harm reduction interventions may have averted 1400 new HCV infections during 2008-2012. CONCLUSIONS: This is the first study to demonstrate that impressive reductions in HCV incidence can be achieved among PWID over a relatively short time period through

  12. Beyond Condoms: Risk Reduction Strategies Among Gay, Bisexual, and Other Men Who Have Sex With Men Receiving Rapid HIV Testing in Montreal, Canada.

    Science.gov (United States)

    Otis, Joanne; McFadyen, Amélie; Haig, Thomas; Blais, Martin; Cox, Joseph; Brenner, Bluma; Rousseau, Robert; Émond, Gilbert; Roger, Michel; Wainberg, Mark

    2016-12-01

    Gay, bisexual, and other men who have sex with men (MSM) have adapted their sexual practices over the course of the HIV/AIDS epidemic based on available data and knowledge about HIV. This study sought to identify and compare patterns in condom use among gay, bisexual, and other MSM who were tested for HIV at a community-based testing site in Montreal, Canada. Results showed that while study participants use condoms to a certain extent with HIV-positive partners and partners of unknown HIV status, they also make use of various other strategies such as adjusting to a partner's presumed or known HIV status and viral load, avoiding certain types of partners, taking PEP, and getting tested for HIV. These findings suggest that MSM who use condoms less systematically are not necessarily taking fewer precautions but may instead be combining or replacing condom use with other approaches to risk reduction.

  13. The Issue of Calculating the Final Temperature of the Products of Rapid Exothermic Chemical Reactions with Significant Energy Release in a Closed Volume

    Science.gov (United States)

    Lazarev, V.; Geidmanis, D.

    2016-02-01

    The theoretical problem solved in this article is the calculation of thermodynamic parameters such as final temperature, distribution of the liquid and dry saturated vapour phases of the substance that are considered to be in thermodynamic equilibrium, and pressure of the system of several reaction products after adding to the system a certain amount of heat or the thermal effect released during rapid exothermic reaction in a closed volume that occurs so fast that it can be considered to be adiabatic, and when the volume of liquid reagents is several orders of magnitude less than the volume of the reactor. The general multi-substance problem is reduced to a theoretical problem for one substance of calculation thermodynamic parameters of system after adding a certain amount of heat that gives theoretically rigorous isochoric calculation. In this article, we substantiate our view that isochoric pass of calculation is more robust compared to seemingly more natural isobaric pass of calculation, if the later involves quite not trivial calculation of the adiabatic compression of a two-phase system (liquid - dry saturated vapour) that can pass itself into another kind of state (liquid - wet saturated vapour), which requires, apparently, more complex descriptions compared with isochoric calculation because the specific heat capacity of wet saturated vapour can be negative. The solved theoretical problem relates to a practical problem that has been a driver for our research as part of a design of the reactor of the titanium reduction from magnesium and titanium tetrachloride supplied into atmosphere of the reactor at high temperatures when both reagents are in gaseous state. The reaction is known to be exothermic with a high thermal effect, and estimate of the final temperature and pressure of the products of reaction, for instance, designing the reactor allows eliminating the possibility of the reaction products to penetrate backwards into supply tracts of the reagents

  14. Evidence of chemical stimulation of hepatic metabolism by an experimental acetanilide (FOE 5043) indirectly mediating reductions in circulating thyroid hormone levels in the male rat.

    Science.gov (United States)

    Christenson, W R; Becker, B D; Wahle, B S; Moore, K D; Dass, P D; Lake, S G; Van Goethem, D L; Stuart, B P; Sangha, G K; Thyssen, J H

    1996-02-01

    N-(4-Fluorophenyl)-N-(1-methylethyl)-2-[[5-(trifluoromethyl)-1,3, 4-thiadiazol-2-yl]oxy]acetamide (FOE 5043) is a new acetanilide-type herbicide undergoing regulatory testing. Previous work in this laboratory suggested that FOE 5043-induced reductions in serum thyroxine (T4) levels were mediated via an extrathyroidal site of action. The possibility that the alterations in circulating T4 levels were due to chemical induction of hepatic thyroid hormone metabolism was investigated. Treatment with FOE 5043 at a rate of 1000 ppm as a dietary admixture was found to significantly increase the clearance of [125I]T4 from the serum, suggesting an enhanced excretion of the hormone. In the liver, the activity of hepatic uridine glucuronosyl transferase, a major pathway of thyroid hormone biotransformation in the rat, increased in a statistically significant and dose-dependent manner; conversely, hepatic 5'-monodeiodinase activity trended downward with dose. Bile flow as well as the hepatic uptake and biliary excretion of [125I]T4 were increased following exposure to FOE 5043. Thyroidal function, as measured by the discharge of iodide ion in response to perchlorate, and pituitary function, as measured by the capacity of the pituitary to secrete thyrotropin in response to an exogenous challenge by hypothalamic thyrotropin releasing hormone, were both unchanged from the controlled response. These data suggest that the functional status of the thyroid and pituitary glands has not been altered by treatment with FOE 5043 and that reductions in circulating levels of T4 are being mediated indirectly through an increase in the biotransformation and excretion of thyroid hormone in the liver.

  15. Managing Community Resilience to Climate Extremes, Rapid Unsustainable Urbanization, Emergencies of Scarcity, and Biodiversity Crises by Use of a Disaster Risk Reduction Bank.

    Science.gov (United States)

    Canyon, Deon V; Burkle, Frederick M; Speare, Rick

    2015-12-01

    Earth's climate is changing and national and international decision-makers are recognizing that global health security requires urgent attention and a significant investment to protect the future. In most locations, current data are inadequate to conduct a full assessment of the direct and indirect health impacts of climate change. All states require this information to evaluate community-level resilience to climate extremes and climate change. A model that is being used successfully in the United Kingdom, Australia, and New Zealand is recommended to generate rapid information to assist decision-makers in the event of a disaster. The model overcomes barriers to success inherent in the traditional ''top-down'' approach to managing crises and recognizes the capacity of capable citizens and community organizers to facilitate response and recovery if provided the opportunity and resources. Local information is a prerequisite for strategic and tactical statewide planning. Time and resources are required to analyze risks within each community and what is required to prevent (mitigate), prepare, respond, recover (rehabilitate), anticipate, and assess any threatening events. Specific requirements at all levels from state to community must emphasize community roles by focusing on how best to maintain, respond, and recover public health protections and the infrastructure necessary for health security.

  16. Oxidation and Reduction of Iron-Titanium Oxides in Chemical Looping Combustion: A Phase-Chemical Description Oxydation et réduction des minerais de fer-titane dans la combustion en boucle chimique

    Directory of Open Access Journals (Sweden)

    den Hoed P.

    2011-05-01

    Full Text Available Ilmenite (FeTiO3 is being explored as an oxygen carrier in chemical looping processes. Its reduction and oxidation are described by the system Fe-Fe2O3-TiO2-Ti2O3. The phase diagram at 1 000°C, presented here, offers a useful tool for predicting reactions and their products. We see that Fe2TiO5 (pseudobrookite and TiO2 (rutile form a stable phase assemblage following the oxidation of FeTiO3 (ilmenite in air. The subsequent reduction of Fe2TiO5 at oxygen partial pressures of 10-15.5atm stabilizes Fe1.02Ti0.98O3, a solid solution of ilmenite. Further reduction will produce metallic iron, which compromises the integrity of the oxygen carrier for chemical looping processes. We speculate that the reduction of Fe-Ti oxides in several practical instances does not reach completion (and equilibrium under the imposed atmospheres operating in fuel reactors. L’ilménite (FeTiO3 est considéré comme un transporteur d’oxygène potentiel pour les procédés en boucle chimique. Ses mécanismes de réduction et d’oxydation sont décrits à travers le système Fe-Fe2O3-TiO2-TiO3. Le diagramme de phase à 1 000°C, présenté ici, est un outil utile pour prédire les réactions et les produits. Nous constatons que Fe2TiO5 (pseudobrookite et TiO2 (rutile forment un assemblage de phase stable après oxydation de l’ilménite (FeTiO3 dans l’air. La réduction subséquente de Fe2TiO5 à la pression partielle de 10−15,5atm stabilise vers Fe1.02Ti0.98O3, une solution solide d’ilménite. Une réduction plus poussée va produire du fer métallique et compromettre l’intégrité du transporteur d’oxygène dans la boucle chimique. Il est probable que la réduction des oxydes Fe-Ti ne soit pas, en pratique, complète et n’atteigne pas l’équilibre dans les conditions rencontrées en opération dans les réacteurs de réduction.

  17. Rapid synthesis of silver nanoparticles from Polylthia longifolia leaves

    Directory of Open Access Journals (Sweden)

    Tollamadugu Nagavenkata

    2012-10-01

    Full Text Available Objective: Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and flammable. In this research article we present a simple and eco-friendly biosynthesis of silver nanoparticles using P. longifolia leaf extract as reducing agent. Methods: Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy (TEM was performed. Results: TEM showed the formation of silver nanoparticles with an average size of 57 nm. Conclusions: P. longifolia demonstrated strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0. Biological methods are a good competent for the chemical procedures, which are enviro- friendly and convenient.

  18. Intensive lifestyle intervention provides rapid reduction of serum fatty acid levels in women with severe obesity without lowering omega-3 to unhealthy levels.

    Science.gov (United States)

    Lin, C; Andersen, J R; Våge, V; Rajalahti, T; Mjøs, S A; Kvalheim, O M

    2016-08-01

    Serum fatty acid (FA) levels were monitored in women with severe obesity during intensive lifestyle intervention. At baseline, total FA levels and most individual FAs were elevated compared to a matching cohort of normal and overweight women (healthy controls). After 3 weeks of intensive lifestyle intervention, total level was only 11-12% higher than in the healthy controls and with almost all FAs being significantly lower than at baseline, but with levels of omega-3 being similar to the healthy controls. This is contrary to observations for patients subjected to bariatric surgery where omega-3 levels dropped to levels significantly lower than in the lifestyle patients and healthy controls. During the next 3 weeks of treatment, the FA levels in lifestyle patients were unchanged, while the weight loss continued at almost the same rate as in the first 3 weeks. Multivariate analysis revealed that weight loss and change of serum FA patterns were unrelated outcomes of the intervention for lifestyle patients. For bariatric patients, these processes were associated probably due to reduced dietary input and increased input from the patients' own fat deposits, causing a higher rate of weight loss and simultaneous reduction of the ratio of serum eicosapentaenoic to arachidonic acid. © 2016 World Obesity.

  19. Development and application of a rapid, user-friendly, and inexpensive method to detect Dehalococcoides sp. reductive dehalogenase genes from groundwater.

    Science.gov (United States)

    Kanitkar, Yogendra H; Stedtfeld, Robert D; Hatzinger, Paul B; Hashsham, Syed A; Cupples, Alison M

    2017-06-01

    TaqMan probe-based quantitative polymerase chain reaction (qPCR) specific to the biomarker reductive dehalogenase (RDase) genes is a widely accepted molecular biological tool (MBT) for determining the abundance of Dehalococcoides sp. in groundwater samples from chlorinated solvent-contaminated sites. However, there are significant costs associated with this MBT. In this study, we describe an approach that requires only low-cost laboratory equipment (a bench top centrifuge and a water bath) and requires less time and resources compared to qPCR. The method involves the concentration of biomass from groundwater, without DNA extraction, and loop-mediated isothermal amplification (LAMP) of the cell templates. The amplification products are detected by a simple visual color change (orange/green). The detection limits of the assay were determined using groundwater from a contaminated site. In addition, the assay was tested with groundwater from three additional contaminated sites. The final approach to detect RDase genes, without DNA extraction or a thermal cycler, was successful to 1.8 × 10(5) gene copies per L for vcrA and 1.3 × 10(5) gene copies per L for tceA. Both values are below the threshold recommended for effective in situ dechlorination.

  20. Anaerobic stabilization of waste activated sludge at different temperatures and solid retention times: Evaluation by sludge reduction, soluble chemical oxygen demand release and dehydration capability.

    Science.gov (United States)

    Li, Xiyao; Peng, Yongzhen; He, Yuelan; Wang, Shuying; Guo, Siyu; Li, Lukai

    2017-03-01

    Anaerobic treatment is the most widely used method of waste activated sludge (WAS) stabilization. Using a semi-continuous stirring tank with condensed WAS, we investigated effects of decreasing the solid retention time (SRT) from 32days to 6.4days on sludge reduction, soluble chemical oxygen demand (SCOD) release and dehydration capability, along with anaerobic digestion operated at medium temperature (MT-AD) or anaerobic digestion operated at room temperature (RT-AD). Results showed that effects of temperature on SCOD release were greater at SRT of 32d and 6.4d. When SRT was less than 8d, total solids (TS), volatile solids (VS) and capillary suction time (CST) did not change significantly. CST was lowest at SRT of 10.7days, indicating best condition for sludge dehydration. Principal component analysis (PCA) showed that the most optimum SRT was higher than 10.7d both in MT-AD or RT-AD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Characterization and study of reduction and sulfurization processing in phase transition from molybdenum oxide (MoO{sub 2}) to molybdenum disulfide (MoS{sub 2}) chalcogenide semiconductor nanoparticles prepared by one-stage chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Shomalian, K.; Bagheri-Mohagheghi, M.M.; Ardyanian, M. [Damghan University, School of Physics, Damghan (Iran, Islamic Republic of)

    2017-01-15

    In this research, molybdenum disulfide (MoS{sub 2}) nanoparticles were prepared by chemical reduction method using MoO{sub 3} and thiourea as a precursor. The physical properties of the synthesized MoO{sub 2}-MoS{sub 2} nanoparticles annealed at different temperatures of 200, 300, 750 C have been investigated, before and after exposure to sulfur vapor. The nanostructure of nanoparticles has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) analyses and UV-Vis spectrophotometer. The X-ray diffraction analysis showed the formation of MoS{sub 2} single phase at annealing temperature of 750 C in the presence of sulfur vapor. The Raman spectrum of the nanoparticles revealed that the formation of MoS{sub 2} at 750 C after annealing in sulfur vapor. The values of band gap were obtained in the range of 3.64-3.17 eV and 3.47-1.95 eV for MoS{sub 2} nanoparticles before and after exposure to sulfur vapor, respectively. According to SEM images, the grain size decreases with increasing annealing temperature up to 750 C. Also, nanoplate-nanoparticles of MoS{sub 2} are formed at annealing temperature of 200-750 C. The TEM images of MoS{sub 2} nanoparticles at T{sub a} = 750 C confirm that the nanoparticles have a homogeneous distribution with a hexagonal structure. The FTIR spectra of the MoS{sub 2} nanoparticles showed the peaks at about 467 cm {sup -1} belong to the characteristic bands of Mo-S. (orig.)

  2. Phylogenetic signal detection from an ancient rapid radiation: Effects of noise reduction, long-branch attraction, and model selection in crown clade Apocynaceae.

    Science.gov (United States)

    Straub, Shannon C K; Moore, Michael J; Soltis, Pamela S; Soltis, Douglas E; Liston, Aaron; Livshultz, Tatyana

    2014-11-01

    Crown clade Apocynaceae comprise seven primary lineages of lianas, shrubs, and herbs with a diversity of pollen aggregation morphologies including monads, tetrads, and pollinia, making them an ideal group for investigating the evolution and function of pollen packaging. Traditional molecular systematic approaches utilizing small amounts of sequence data have failed to resolve relationships along the spine of the crown clade, a likely ancient rapid radiation. The previous best estimate of the phylogeny was a five-way polytomy, leaving ambiguous the homology of aggregated pollen in two major lineages, the Periplocoideae, which possess pollen tetrads, and the milkweeds (Secamonoideae plus Asclepiadoideae), which possess pollinia. To assess whether greatly increased character sampling would resolve these relationships, a plastome sequence data matrix was assembled for 13 taxa of Apocynaceae, including nine newly generated complete plastomes, one partial new plastome, and three previously reported plastomes, collectively representing all primary crown clade lineages and outgroups. The effects of phylogenetic noise, long-branch attraction, and model selection (linked versus unlinked branch lengths among data partitions) were evaluated in a hypothesis-testing framework based on Shimodaira-Hasegawa tests. Discrimination among alternative crown clade resolutions was affected by all three factors. Exclusion of the noisiest alignment positions and topologies influenced by long-branch attraction resulted in a trichotomy along the spine of the crown clade consisting of Rhabdadenia+the Asian clade, Baisseeae+milkweeds, and Periplocoideae+the New World clade. Parsimony reconstruction on all optimal topologies after noise exclusion unambiguously supports parallel evolution of aggregated pollen in Periplocoideae (tetrads) and milkweeds (pollinia). Our phylogenomic approach has greatly advanced the resolution of one of the most perplexing radiations in Apocynaceae, providing the

  3. Loop-Mediated Isothermal Amplification (LAMP) for Rapid Detection and Quantification of Dehalococcoides Biomarker Genes in Commercial Reductive Dechlorinating Cultures KB-1 and SDC-9.

    Science.gov (United States)

    Kanitkar, Yogendra H; Stedtfeld, Robert D; Steffan, Robert J; Hashsham, Syed A; Cupples, Alison M

    2016-01-08

    Real-time quantitative PCR (qPCR) protocols specific to the reductive dehalogenase (RDase) genes vcrA, bvcA, and tceA are commonly used to quantify Dehalococcoides spp. in groundwater from chlorinated solvent-contaminated sites. In this study, loop-mediated isothermal amplification (LAMP) was developed as an alternative approach for the quantification of these genes. LAMP does not require a real-time thermal cycler (i.e., amplification is isothermal), allowing the method to be performed using less-expensive and potentially field-deployable detection devices. Six LAMP primers were designed for each of three RDase genes (vcrA, bvcA, and tceA) using Primer Explorer V4. The LAMP assays were compared to conventional qPCR approaches using plasmid standards, two commercially available bioaugmentation cultures, KB-1 and SDC-9 (both contain Dehalococcoides species). DNA was extracted over a growth cycle from KB-1 and SDC-9 cultures amended with trichloroethene and vinyl chloride, respectively. All three genes were quantified for KB-1, whereas only vcrA was quantified for SDC-9. A comparison of LAMP and qPCR using standard plasmids indicated that quantification results were similar over a large range of gene concentrations. In addition, the quantitative increase in gene concentrations over one growth cycle of KB-1 and SDC-9 using LAMP was comparable to that of qPCR. The developed LAMP assays for vcrA and tceA genes were validated by comparing quantification on the Gene-Z handheld platform and a real-time thermal cycler using DNA isolated from eight groundwater samples obtained from an SDC-9-bioaugmented site (Tulsa, OK). These assays will be particularly useful at sites subject to bioaugmentation with these two commonly used Dehalococcoides species-containing cultures. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  4. Rapid screening of chemical warfare nerve agent metabolites in urine by atmospheric solids analysis probe-mass spectroscopy (ASAP-MS).

    Science.gov (United States)

    Zydel, Frank; Smith, J Richard; Pagnotti, Vincent S; Lawrence, Richard J; McEwen, Charles N; Capacio, Benedict R

    2012-01-01

    Exposures to organophosphorus nerve agents (OPNA) remain a threat to both civilian and military populations. Verification of exposures typically involves determinations of urinary metabolites or adducted proteins in blood. Urinary alkyl methylphosphonic acid metabolites resulting from hydrolysis of OPNAs provide a convenient marker for OPNA exposure. In a military setting, urine is a relatively easy sample to obtain, and a rapid turnaround for analyses for the identification of metabolites is critical for field commanders. Timely information on use and identity of OPNAs facilitates decisions regarding employment of personal protective equipment and additional strategies to mitigate additional exposure(s). Herein, we report the development of a rapid mass spectrometric (MS) method to identify OPNA metabolites directly from urine with no sample preparation. Synthetic urine spiked with multiple OPNA metabolites was analyzed using an atmospheric solids analysis probe (ASAP) attached to a high resolution mass spectrometer. The alkyl methylphosphonic acid metabolites resulting from hydrolysis of sarin, cyclosarin, soman, and Russian VX were clearly detectable down to a level of 1.0 ng/ml. The ability to rapidly detect OPNA metabolites in unprepared urine allows for the design of a field-deployable device that could afford field personnel the ability to rapidly screen individuals for specific OPNA exposure. In addition, this provides proof-of-concept evidence that a fieldable ASAP-MS device could afford personnel the ability to rapidly detect OPNAs on skin, equipment, and other porous surfaces. Published 2012. This article is a US Government work and is in the public domain in the USA. Copyright © 2012 John Wiley & Sons, Ltd.

  5. Rapid Induction of Cerebral Organoids From Human Induced Pluripotent Stem Cells Using a Chemically Defined Hydrogel and Defined Cell Culture Medium.

    Science.gov (United States)

    Lindborg, Beth A; Brekke, John H; Vegoe, Amanda L; Ulrich, Connor B; Haider, Kerri T; Subramaniam, Sandhya; Venhuizen, Scott L; Eide, Cindy R; Orchard, Paul J; Chen, Weili; Wang, Qi; Pelaez, Francisco; Scott, Carolyn M; Kokkoli, Efrosini; Keirstead, Susan A; Dutton, James R; Tolar, Jakub; O'Brien, Timothy D

    2016-07-01

    Tissue organoids are a promising technology that may accelerate development of the societal and NIH mandate for precision medicine. Here we describe a robust and simple method for generating cerebral organoids (cOrgs) from human pluripotent stem cells by using a chemically defined hydrogel material and chemically defined culture medium. By using no additional neural induction components, cOrgs appeared on the hydrogel surface within 10-14 days, and under static culture conditions, they attained sizes up to 3 mm in greatest dimension by day 28. Histologically, the organoids showed neural rosette and neural tube-like structures and evidence of early corticogenesis. Immunostaining and quantitative reverse-transcription polymerase chain reaction demonstrated protein and gene expression representative of forebrain, midbrain, and hindbrain development. Physiologic studies showed responses to glutamate and depolarization in many cells, consistent with neural behavior. The method of cerebral organoid generation described here facilitates access to this technology, enables scalable applications, and provides a potential pathway to translational applications where defined components are desirable. Tissue organoids are a promising technology with many potential applications, such as pharmaceutical screens and development of in vitro disease models, particularly for human polygenic conditions where animal models are insufficient. This work describes a robust and simple method for generating cerebral organoids from human induced pluripotent stem cells by using a chemically defined hydrogel material and chemically defined culture medium. This method, by virtue of its simplicity and use of defined materials, greatly facilitates access to cerebral organoid technology, enables scalable applications, and provides a potential pathway to translational applications where defined components are desirable. ©AlphaMed Press.

  6. Rapid determination of chemical composition and classification of bamboo fractions using visible-near infrared spectroscopy coupled with multivariate data analysis.

    Science.gov (United States)

    Yang, Zhong; Li, Kang; Zhang, Maomao; Xin, Donglin; Zhang, Junhua

    2016-01-01

    During conversion of bamboo into biofuels and chemicals, it is necessary to efficiently predict the chemical composition and digestibility of biomass. However, traditional methods for determination of lignocellulosic biomass composition are expensive and time consuming. In this work, a novel and fast method for quantitative and qualitative analysis of chemical composition and enzymatic digestibilities of juvenile bamboo and mature bamboo fractions (bamboo green, bamboo timber, bamboo yellow, bamboo node, and bamboo branch) using visible-near infrared spectra was evaluated. The developed partial least squares models yielded coefficients of determination in calibration of 0.88, 0.94, and 0.96, for cellulose, xylan, and lignin of bamboo fractions in raw spectra, respectively. After visible-near infrared spectra being pretreated, the corresponding coefficients of determination in calibration yielded by the developed partial least squares models are 0.994, 0.990, and 0.996, respectively. The score plots of principal component analysis of mature bamboo, juvenile bamboo, and different fractions of mature bamboo were obviously distinguished in raw spectra. Based on partial least squares discriminant analysis, the classification accuracies of mature bamboo, juvenile bamboo, and different fractions of bamboo (bamboo green, bamboo timber, bamboo yellow, and bamboo branch) all reached 100 %. In addition, high accuracies of evaluation of the enzymatic digestibilities of bamboo fractions after pretreatment with aqueous ammonia were also observed. The results showed the potential of visible-near infrared spectroscopy in combination with multivariate analysis in efficiently analyzing the chemical composition and hydrolysabilities of lignocellulosic biomass, such as bamboo fractions.

  7. Chemical cardioversion of recent-onset atrial fibrillation in the emergency department using vernakalant hydrochloride achieves safe and rapid restoration of sinus rhythm and facilitates same day discharge.

    Science.gov (United States)

    Stoneman, P; Gilligan, P; Mahon, P; Sheahan, R

    2017-11-01

    Vernakalant hydrochloride is a rapid-acting antiarrhythmic drug licensed in the EU since 2010 for the conversion of recent-onset atrial fibrillation with proven efficacy and safety when compared with placebo and amiodarone in randomized clinical trials. The aim of our study was to determine the feasibility of same day discharge (following 2 h monitoring) from the emergency department after successful cardioversion using vernakalant hydrochloride. Patients with recent-onset atrial fibrillation treated in the emergency department of a large Dublin academic teaching hospital. Patients received a maximum of two weight based 10 min infusions of vernakalant. Hypotensive events (>30% initial blood pressure), arrhythmias, conversion rates, and time to conversion were recorded. Sinus rhythm was restored in 35 out of 42 patients (83%) in an average of 8.8 min (median 8 min), average CHA2DS2-VASc of 0.92, HAS-BLED of 0.21 and average symptoms duration of 12 h. There were no hypotensive or arrhythmogenic events. 41 out of 42 patients were discharged after 2 h of monitoring. Vernakalant hydrochloride has provided a quick, safe, and practical means of achieving rapid restoration of sinus rhythm in our ED population with stable recent-onset AF who would otherwise not have undergone routine electrically cardioversion and same day discharge.

  8. Use of HPLC/UPLC-spectrophotometry for detection of formazan in in vitro Reconstructed human Tissue (RhT)-based test methods employing the MTT-reduction assay to expand their applicability to strongly coloured test chemicals.

    Science.gov (United States)

    Alépée, N; Barroso, J; De Smedt, A; De Wever, B; Hibatallah, J; Klaric, M; Mewes, K R; Millet, M; Pfannenbecker, U; Tailhardat, M; Templier, M; McNamee, P

    2015-06-01

    A number of in vitro test methods using Reconstructed human Tissues (RhT) are regulatory accepted for evaluation of skin corrosion/irritation. In such methods, test chemical corrosion/irritation potential is determined by measuring tissue viability using the photometric MTT-reduction assay. A known limitation of this assay is possible interference of strongly coloured test chemicals with measurement of formazan by absorbance (OD). To address this, Cosmetics Europe evaluated use of HPLC/UPLC-spectrophotometry as an alternative formazan measurement system. Using the approach recommended by the FDA guidance for validation of bio-analytical methods, three independent laboratories established and qualified their HPLC/UPLC-spectrophotometry systems to reproducibly measure formazan from tissue extracts. Up to 26 chemicals were then tested in RhT test systems for eye/skin irritation and skin corrosion. Results support that: (1) HPLC/UPLC-spectrophotometry formazan measurement is highly reproducible; (2) formazan measurement by HPLC/UPLC-spectrophotometry and OD gave almost identical tissue viabilities for test chemicals not exhibiting colour interference nor direct MTT reduction; (3) independent of the test system used, HPLC/UPLC-spectrophotometry can measure formazan for strongly coloured test chemicals when this is not possible by absorbance only. It is therefore recommended that HPLC/UPLC-spectrophotometry to measure formazan be included in the procedures of in vitro RhT-based test methods, irrespective of the test system used and the toxicity endpoint evaluated to extend the applicability of these test methods to strongly coloured chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Rapid Data Assimilation in the Indoor Environment: theory and examples from real-time interpretation of indoor plumes of airborne chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Gadgil, Ashok; Sohn, Michael; Sreedharan, Priya

    2008-09-01

    Releases of acutely toxic airborne contaminants in or near a building can lead to significant human exposures unless prompt response measures are identified and implemented. Commonly, possible responses include conflicting strategies, such as shutting the ventilation system off versus running it in a purge (100percent outside air) mode, or having occupants evacuate versus sheltering in place. The right choice depends in part on quickly identifying the source locations, the amounts released, and the likely future dispersion routes of the pollutants. This paper summarizes recent developments to provide such estimates in real time using an approach called Bayesian Monte Carlo updating. This approach rapidly interprets measurements of airborne pollutant concentrations from multiple sensors placed in the building and computes best estimates and uncertainties of the release conditions. The algorithm is fast, capable of continuously updating the estimates as measurements stream in from sensors. The approach is employed, as illustration, to conduct two specific investigations under different situations.

  10. Rapid Data Assimilation in the Indoor Environment: Theory and Examples from Real-Time Interpretation of Indoor Plumes of Airborne Chemical

    Energy Technology Data Exchange (ETDEWEB)

    Gadgil, Ashok; Gadgil, Ashok; Sohn, Michael; Sreedharan, Priya

    2007-08-01

    Releases of acutely toxic airborne contaminants in or near a building can lead to significant human exposures unless prompt response measures are identified and implemented. Possible responses include conflicting options, such as shutting the ventilation system off versus running it in a purge (100 percent outside air) mode, or having occupants evacuate versus sheltering in place. The right choice depends in part on quickly identifying the source location, the amount released, and the likely future dispersion of the pollutant. This paper summarizes recent developments to provide such estimates in real time using an approach called Bayesian Monte Carlo updating. This approach rapidly interprets measurements of airborne pollutant concentrations from multiple sensors placed in the building, and computes best estimates and uncertainties of the release conditions. The algorithm is fast, and can continuously update the estimates as measurements stream in from sensors. As an illustration, two specific applications of the approach are described.

  11. Rapid reduction in blood flow to the rat ventral prostate gland after castration: preliminary evidence that androgens influence prostate size by regulating blood flow to the prostate gland and prostatic endothelial cell survival.

    Science.gov (United States)

    Shabsigh, A; Chang, D T; Heitjan, D F; Kiss, A; Olsson, C A; Puchner, P J; Buttyan, R

    1998-08-01

    Androgenic steroids regulate the development and size of the mammalian prostate gland. The mechanism(s) for this growth control might involve a direct effect on prostate cell proliferation and survival as well as more complex effects on the tissue environment supporting nourishment and oxygenation. In this study, we evaluated an animal model of androgen action on the prostate, the rat ventral prostate gland, to determine whether acute androgen withdrawal, by means of castration, might alter the primary blood flow to the prostate gland and for the effects of castration on prostatic endothelial cell viability. Groups of rats studied included intact control males, males that had been surgically castrated, or males that received a sham-surgical castration. Relative blood flow (RBF) to the rat ventral prostate glands and rat bladders were measured at 18 and 24 hr after castration or sham castration using a fluorescent microsphere infusion technique. Thin sections from fixed and embedded rat ventral prostate glands obtained from unoperated or 12-hr castrated rats were analyzed by the TUNEL immunostaining technique to microscopically identify and quantify apoptotic epithelial, stromal, and endothelial cells. RBF to the rat ventral prostate was reduced by 38%, at 18 hr after castration when compared with intact or sham-operated rats and by 45% at 24 hr after castration (P=0.038 unoperated/0.025 sham operated). In contrast, RBF to the bladder was not significantly different between any of the groups in the 24-hr castrate experiment. TUNEL staining analysis of ventral prostate tissues obtained from 12-hr castrated rats showed only rare TUNEL-positive epithelial cells similar to the control tissue but significantly increased TUNEL labeling for endothelial and other ventral prostate stromal cells. Castration resulted in a rapid and significant reduction of blood flow to the mature rat ventral prostate gland that was not seen in the bladder. This reduction precedes the

  12. Reduction of hydrogen-induced optical losses of plasma-enhanced chemical vapor deposition silicon oxynitride by phosphorus doping and heat treatment

    NARCIS (Netherlands)

    Hussein, M.G.; Worhoff, Kerstin; Sengo, G.; Sengo, G.; Driessen, A.

    2007-01-01

    Plasma enhanced chemical vapor deposition phosphoros-doped silicon oxynitride (SiON) layers with a refractive index of 1.505 were deposited from $N_{2}O$, 2% $SiH_{4}/N_{2}$, and 5% $PH_{3}/Ar$ gaseous mixtures. The $PH_{3}/Ar$ flow rate was varied to investigate the effect of the dopant to the

  13. Rapid screening of anabolic steroids in horse urine with ultra-high-performance liquid chromatography/tandem mass spectrometry after chemical derivatisation.

    Science.gov (United States)

    Wong, Colton H F; Leung, David K K; Tang, Francis P W; Wong, Jenny K Y; Yu, Nola H; Wan, Terence S M

    2012-04-06

    Liquid chromatography/mass spectrometry (LC/MS) has been successfully applied to the detection of anabolic steroids in biological samples. However, the sensitive detection of saturated hydroxysteroids, such as androstanediols, by electrospray ionisation (ESI) is difficult because of their poor ability to ionise. In view of this, chemical derivatisation has been used to enhance the detection sensitivity of hydroxysteroids by LC/MS. This paper describes the development of a sensitive ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) method for the screening of anabolic steroids in horse urine by incorporating a chemical derivatisation step, using picolinic acid as the derivatisation reagent. The method involved solid-phase extraction (SPE) of both free and conjugated anabolic steroids in horse urine using a polymer-based SPE cartridge (Abs Elut Nexus). The conjugated steroids in the eluate were hydrolysed by methanolysis and the resulting extract was further cleaned up by liquid-liquid extraction. The resulting free steroids in the extract were derivatised with picolinic acid to form the corresponding picolinoyl esters and analysed by UHPLC/MS/MS in the positive ESI mode with selected-reaction-monitoring. Separation of the targeted steroids was performed on a C18 UHPLC column. The instrument turnaround time was 10.5 min inclusive of post-run equilibration. A total of thirty-three anabolic steroids (including 17β-estradiol, 5(10)-estrene-3β,17α-diol, 5α-estrane-3β,17α-diol, 17α-ethyl-5α-estran-3α,17β-diol, 17α-methyl-5α-androstan-3,17β-diols, androstanediols, nandrolone and testosterone) spiked in negative horse urine at the QC levels (ranging from 0.75 to 30 ng/mL) could be consistently detected. The intra-day and inter-day precisions (% RSD) for the peak area ratios were around 7-51% and around 1-72%, respectively. The intra-day and inter-day precisions (% RSD) for the relative retention times were both less than 1% for

  14. Determination of red blood cell fatty acid profiles: Rapid and high-confident analysis by chemical ionization-gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Schober, Yvonne; Wahl, Hans Günther; Renz, Harald; Nockher, Wolfgang Andreas

    2017-01-01

    Cellular fatty acid (FA) profiles have been acknowledged as biomarkers in various human diseases. Nevertheless, common FA analysis by gas chromatography mass spectrometry (GC-MS) requires long analysis time. Hence, there is a need for feasible methods for high throughput analysis in clinical studies. FA was extracted from red blood cells (RBC) and derivatized to fatty acid methyl esters (FAME). A method using gas chromatography tandem mass spectrometry (GC-MS/MS) with ammonia-induced chemical ionization (CI) was developed for the analysis of FA profiles in human RBC. We compared this method with classical single GC-MS using electron impact ionization (EI). The FA profiles of 703 RBC samples were determined by GC-MS/MS. In contrast to EI ammonia-induced CI resulted in adequate amounts of molecular ions for further fragmentation of FAME. Specific fragments for confident quantification and fragmentation were determined for 45 FA. The GC-MS/MS method has a total run time of 9min compared to typical analysis times of up to 60min in conventional GC-MS. Intra and inter assay variations were Analysis of RBC FA composition revealed an age-dependent increase of the omega-3 eicosapentaenoic and docosahexaenoic acid, and a decline of the omega-6 linoleic acid with a corresponding rise of the omega-3 index. The combination of ammonia-induced CI and tandem mass spectrometry after GC separation allows for high-throughput, robust and confident analysis of FA profiles in the clinical laboratory. Copyright © 2016. Published by Elsevier B.V.

  15. Rapid adsorption of toxic Pb(II) ions from aqueous solution using multiwall carbon nanotubes synthesized by microwave chemical vapor deposition technique.

    Science.gov (United States)

    Mubarak, Nabisab Mujawar; Sahu, Jaya Narayan; Abdullah, Ezzat Chan; Jayakumar, Natesan Subramanian

    2016-07-01

    Multiwall carbon nanotubes (MWCNTs) were synthesized using a tubular microwave chemical vapor deposition technique, using acetylene and hydrogen as the precursor gases and ferrocene as catalyst. The novel MWCNT samples were tested for their performance in terms of Pb(II) binding. The synthesized MWCNT samples were characterized using Fourier Transform Infrared (FT-IR), Brunauer, Emmett and Teller (BET), Field Emission Scanning Electron Microscopy (FESEM) analysis, and the adsorption of Pb(II) was studied as a function of pH, initial Pb(II) concentration, MWCNT dosage, agitation speed, and adsorption time, and process parameters were optimized. The adsorption data followed both Freundlich and Langmuir isotherms. On the basis of the Langmuir model, Qmax was calculated to be 104.2mg/g for the microwave-synthesized MWCNTs. In order to investigate the dynamic behavior of MWCNTs as an adsorbent, the kinetic data were modeled using pseudo first-order and pseudo second-order equations. Different thermodynamic parameters, viz., ∆H(0), ∆S(0) and ∆G(0) were evaluated and it was found that the adsorption was feasible, spontaneous and endothermic in nature. The statistical analysis revealed that the optimum conditions for the highest removal (99.9%) of Pb(II) are at pH5, MWCNT dosage 0.1g, agitation speed 160r/min and time of 22.5min with the initial concentration of 10mg/L. Our results proved that microwave-synthesized MWCNTs can be used as an effective Pb(II) adsorbent due to their high adsorption capacity as well as the short adsorption time needed to achieve equilibrium. Copyright © 2016. Published by Elsevier B.V.

  16. Aircraft borne combined measurements of the Fukushima radionuclide Xe-133 and fossil fuel combustion generated pollutants in the TIL - implications for cyclone induced rapid lift and TIL physico-chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Schlager, Hans; Aufmhoff, Heinfried; Baumann, Robert; Schumann, Ulrich [DLR IPA, Oberpfaffenhofen (Germany); Arnold, Frank [MPI Kernphysik, Heidelberg (Germany); DLR IPA, Oberpfaffenhofen (Germany); Simgen, Hardy; Lindemann, Siegfried; Rauch, Ludwig; Kaether, Frank [MPI Kernphysik, Heidelberg (Germany); Pirjola, Liisa [University of Helsinki, Helsinki (Finland)

    2013-07-01

    The radionuclide Xe-133, released by the March 2011 nuclear disaster at Fukushima/Daiichi (hereafter FD), represents an ideal tracer for atmospheric transport. We report the, to our best knowledge, only aircraft borne measurements of FD Xe-133 in the Tropopause Inversion Layer (TIL), indicating rapid lift of polluted planetary boundary layer air to the TIL. On the same research aircraft (FALCON), we have also conducted on-line measurements of fossil fuel combustion generated pollutant gases (SO{sub 2} and other species), which had increased concentrations in the TIL. In addition, we have conducted supporting model simulations of transport, chemical processes, and aerosol processes. Our investigations reveal a potentially important impact of East-Asian cyclone induced pollutants transport to the TIL. This impact includes particularly aerosol formation.

  17. Study of film graphene/graphene oxide obtained by partial reduction chemical of oxide graphite; Estudo de filme de grafeno/oxido de grafeno obtido por reducao quimica parcial do oxido de grafite

    Energy Technology Data Exchange (ETDEWEB)

    Gascho, J.L.S.; Costa, S.F.; Hoepfner, J.C.; Pezzin, S.H., E-mail: juliagascho@hotmail.com [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2014-07-01

    This study investigated the morphology of graphene/graphene oxide film obtained by partial chemical reduction of graphite oxide (OG) as well as its resistance to solvents. Films of graphene/graphene oxide are great candidates for replacement of indium oxide doped with tin (ITO) in photoelectric devices. The OG was obtained from natural graphite, by Hummer's method modified, and its reduction is made by using sodium borohydride. Infrared spectroscopy analysis of Fourier transform (FTIR), Xray diffraction (XRD) and scanning electron microscopy, high-resolution (SEM/FEG) for the characterization of graphene/graphene oxide film obtained were performed. This film proved to be resilient, not dispersing in any of the various tested solvents (such as ethanol, acetone and THF), even under tip sonication, this resistance being an important property for the applications. Furthermore, the film had a morphology similar to that obtained by other preparation methods.(author)

  18. Impact of reduction dose, time and method of application of chemical fertilizer on mung bean under old alluvial soil, West Bengal, India

    Directory of Open Access Journals (Sweden)

    Naba Kumar Mondal

    2014-08-01

    Full Text Available Field experiments were conducted with mung bean (Vigna radiata L. Wilczek consecutively for three years (2009, 2010, and 2011 in the Crop Research and Seed Multiplication Farm, Burdwan University, West Bengal, India. In the first two years, varietals screening of mung bean under recommended dose of chemical fertilizer (20:40:20 were performed with five varieties with a local variety of mung bean during February to May of 2009. In the second year, one experiment was conducted with six different reduced dose of chemical fertilizer. In the third year, five different method and time of application of biofertilizer were applied to study the effects on agronomic traits and growth attributes of mung bean. The variety PDM-54 a significant higher seed yield along with other yield contributing factors, which was found to be superior to other varieties. In 2010, seed yield was found to be the best for 30% less nitrogenous and 25% less phosphate fertilizer along with recommended dose of chemical fertilizer. In 2011, the best yield was given by the treatment of basal @ 0.75 kg ha-1 + 1.5 kg ha-1 soil application after 21 days + 0.75 kg ha-1 as soil application + best dose of previous year.

  19. Effects of rapid thermal annealing on structural, chemical, and electrical characteristics of atomic-layer deposited lanthanum doped zirconium dioxide thin film on 4H-SiC substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Way Foong, E-mail: wayfoong317@yahoo.com.sg [Institute of Nano Optoelectronics Research and Technology, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Centre for Research Initiatives (CRI) Natural Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Quah, Hock Jin, E-mail: jinquah1st@hotmail.com [Institute of Nano Optoelectronics Research and Technology, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Centre for Research Initiatives (CRI) Natural Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Lu, Qifeng, E-mail: Qifeng@liverpool.ac.uk [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Mu, Yifei, E-mail: Y.mu@student.liverpool.ac.uk [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Ismail, Wan Azli Wan, E-mail: azli.ismail@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Rahim, Bazura Abdul, E-mail: bazura@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Esa, Siti Rahmah, E-mail: rahmah.esa@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Kee, Yeh Yee, E-mail: yy.kee@mimos.my [Advance Analytical Services Lab, MIMOS Wafer Fab, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia); Zhao, Ce Zhou, E-mail: cezhou.zhao@xjtlu.edu.cn [Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Department of Electrical and Electronic Engineering, Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123 (China); and others

    2016-03-01

    Graphical abstract: - Highlights: • Studies of RTA temperatures on La doped ZrO2 atomic layer deposited on 4HSiC. • Oxygen vacancies improved insulating and catalytic properties of La doped ZrO2. • 700 °C annealed sample showed the highest EB, k value, and sensitivity on O2. • La doped ZrO2 was proposed as a potential metal reactive oxide on 4H-SiC. - Abstract: Effects of rapid thermal annealing at different temperatures (700–900 °C) on structural, chemical, and electrical characteristics of lanthanum (La) doped zirconium oxide (ZrO{sub 2}) atomic layer deposited on 4H-SiC substrates have been investigated. Chemical composition depth profiling analysis using X-ray photoelectron spectroscopy (XPS) and cross-sectional studies using high resolution transmission electron microscopy equipped with energy dispersive X-ray spectroscopy line scan analysis were insufficient to justify the presence of La in the investigated samples. The minute amount of La present in the bulk oxide was confirmed by chemical depth profiles of time-of-flight secondary ion mass spectrometry. The presence of La in the ZrO{sub 2} lattice led to the formation of oxygen vacancies, which was revealed through binding energy shift for XPS O 1s core level spectra of Zr−O. The highest amount of oxygen vacancies in the sample annealed at 700 °C has yielded the acquisition of the highest electric breakdown field (∼ 6.3 MV/cm) and dielectric constant value (k = 23) as well as the highest current–time (I–t) sensor response towards oxygen gas. The attainment of both the insulating and catalytic properties in the La doped ZrO{sub 2} signified the potential of the doped ZrO{sub 2} as a metal reactive oxide on 4H-SiC substrate.

  20. Optimal reduction of chemical oxygen demand and NH3-N from landfill leachate using a strongly resistant novel Bacillus salmalaya strain.

    Science.gov (United States)

    Dadrasnia, Arezoo; Azirun, Mohd Sofian; Ismail, Salmah Binti

    2017-11-28

    When the unavoidable waste generation is considered as damaging to our environment, it becomes crucial to develop a sustainable technology to remediate the pollutant source towards an environmental protection and safety. The development of a bioengineering technology for highly efficient pollutant removal is this regard. Given the high ammonia nitrogen content and chemical oxygen demand of landfill leachate, Bacillus salmalaya strain 139SI, a novel resident strain microbe that can survive in high ammonia nitrogen concentrations, was investigated for the bioremoval of ammonia nitrogen from landfill leachate. The treatability of landfill leachate was evaluated under different treatment parameters, such as temperature, inoculum dosage, and pH. Results demonstrated that bioaugmentation with the novel strain can potentially improve the biodegradability of landfill leachate. B. salmalaya strain 139SI showed high potential to enhance biological treatment given its maximum NH3-N and COD removal efficiencies. The response surface plot pattern indicated that within 11 days and under optimum conditions (10% v/v inoculant, pH 6, and 35 °C), B. salmalaya strain139SI removed 78% of ammonia nitrogen. At the end of the study, biological and chemical oxygen demands remarkably decreased by 88% and 91.4%, respectively. Scanning electron microscopy images revealed that ammonia ions covered the cell surface of B. salmalaya strain139SI. Therefore, novel resistant Bacillus salmalaya strain139SI significantly reduces the chemical oxygen demand and NH3-N content of landfill leachate. Leachate treatment by B. salmalaya strain 139SI within 11 days.

  1. Reductive de-polymerization of kraft lignin for chemicals and fuels using formic acid as an in-situ hydrogen source.

    Science.gov (United States)

    Huang, Shanhua; Mahmood, Nubla; Tymchyshyn, Matthew; Yuan, Zhongshun; Xu, Chunbao Charles

    2014-11-01

    In this study, formic acid (FA) was employed as an in-situ hydrogen donor for the reductive de-polymerization of kraft lignin (KL). Under the optimum operating conditions, i.e., 300 °C, 1 h, 18.6 wt.% substrate concentration, 50/50 (v/v) water-ethanol medium with FA at a FA-to-lignin mass ratio of 0.7, KL (Mw∼10,000 g/mol) was effectively de-polymerized, producing de-polymerized lignin (DL, Mw 1270 g/mol) at a yield of ∼90 wt.% and polymerization of KL. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. One-step wet chemical deposition of NiO from the electrochemical reduction of nitrates in ionic liquid based electrolytes

    OpenAIRE

    Azaceta, Eneko; Tuyen, Ngo T.; Pickup, David F.; Rogero, Celia; Ortega, J. Enrique; Miguel, Óscar; Grande, Hans-Jurgen; Tena-Zaera, Ramón

    2013-01-01

    Aprotic PYR14TFSI (1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)) ionic liquid served to develop a new electrochemical route for one-step deposition of NiO from PYR14NO3 reduction (1-butyl-1-methylpyrrolidinium nitrate) in a Ni(TFSI)2 (Nickel (II) bis(trifluoromethanesulfonyl)imide) containing electrolyte. The high solubility of the novel PYR14NO3 salt in PYR14TFSI (>0.1 M) in comparison with other oxygenated precursors such as oxygen gas, NaNO 3 or KNO3 (i.e. 10-15 mM) allows t...

  3. Solar-chemical contributions to the reduction of CO{sub 2} emissions; Solarchemische Beitraege zur Reduktion des CO{sub 2}-Ausstosses. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Alxneit, I.; Gstoehl, D.; Wieckert, C.

    2008-04-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) reports on the production of zinc by using concentrated solar energy to dissociate zinc oxide. The zinc can be used to produce hydrogen from water or as an electrode in zinc-air batteries or fuel cells. The project aimed to develop a thermo-chemical cycle for the production of 'solar' hydrogen. The three sub-projects - the creation of a model that describes the process, experimental determination of nucleation and condensation rates and the experimental determination of the oxidation kinetics - are described and discussed.

  4. Kinetic studies of molecular oxygen reduction on W{sub 0.013}Ru{sub 1.27}Se thin films chemically synthesized

    Energy Technology Data Exchange (ETDEWEB)

    Solorza-Feria, O.; Ramirez-Raya, S.; Rivera-Noriega, R.; Ordonez-Regil, E.; Fernandez-Valverde, S.M. [IPN, Mexico (Mexico). Dept. Quimica]|[Gerencia de Investigacion Basica, Instituto Nacional de Investigaciones Nucleares, A. Postal 18-1027, Mexico D.F. 11870 (Mexico)

    1997-12-31

    The reaction of molecular oxygen reduction was investigated on an amorphous W{sub 0.013}Ru{sub 1.27}Se electrocatalyst compound in a 0.5 M H{sub 2}SO{sub 4} solution. The electrocatalyst was synthesized by reacting transition metal carbonyl compounds with the elemental selenium in 1,2-dichlorobenzene (b.p.{approx}180 C), under refluxing conditions for 20 Hs. The sample was characterized by neutron activation analysis (NAA) and scanning electron microscopy (SEM). The characterization of the electrocatalyst indicated that the material, in a thin film form, consisted of an amorphous phase with a distribution of nano-sized particles. Electrochemical studies were carried out by a using a rotating disc electrode (RDE) and a rotating ring-disc electrode (RRDE) techniques. The RDE and RRDE measurements indicated that the electrocatalyst is active for molecular oxygen reduction in acid media with multi-electron charge transfer (n=4e{sup -}), to form water. The reaction order and the heterogeneous rate constants for a simple mechanism were evaluated. (orig.) 21 refs.

  5. Synergetic effect of ZrO2 on the oxidation-reduction reaction of Fe2O3 during chemical looping combustion

    Science.gov (United States)

    Tan, Qinliang; Qin, Wu; Chen, Qiuluan; Dong, Changqing; Li, Wenyan; Yang, Yongping

    2012-10-01

    Fe2O3/ZrO2 model oxygen carrier is constructed at atomic-level precision under ultra-high-vacuum conditions. Based on density functional theory calculations and molecular dynamical simulations, structure and energy analysis suggests that the complex Fe2O3/ZrO2 is stable and more chemically active than the pure Fe2O3, ZrO2 promotes the adsorption of CO, which is chemisorption rather than physisorption on the pure Fe2O3 surface. Interface electronic interaction of Fe2O3/ZrO2 makes Fe2O3 positive to accept electron from CO easily and hence promoting the chemisorption of CO and the formation of carbonate species, while such electronic interaction makes it relatively more difficult in oxidizing Fe2O2 supported on ZrO2. However, all reaction barrier energies are small enough for Fe2O2 oxidation to happen under high temperature in the CLC system. Both CO oxidation by Fe2O3/ZrO2 related to the fuel reactor in the chemical looping combustion (CLC) system and Fe2O2/ZrO2 oxidation by O2 related to the air reactor in CLC system illustrate the synergetic effect of ZrO2 on the CO oxidation and Fe2O2 oxidation.

  6. A rapid and high-precision method for sulfur isotope δ(34)S determination with a multiple-collector inductively coupled plasma mass spectrometer: matrix effect correction and applications for water samples without chemical purification.

    Science.gov (United States)

    Lin, An-Jun; Yang, Tao; Jiang, Shao-Yong

    2014-04-15

    Previous studies have indicated that prior chemical purification of samples, although complex and time-consuming, is essential in obtaining precise and accurate results for sulfur isotope ratios using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). In this study, we introduce a new, rapid and precise MC-ICP-MS method for sulfur isotope determination from water samples without chemical purification. The analytical work was performed on an MC-ICP-MS instrument with medium mass resolution (m/Δm ~ 3000). Standard-sample bracketing (SSB) was used to correct samples throughout the analytical sessions. Reference materials included an Alfa-S (ammonium sulfate) standard solution, ammonium sulfate provided by the lab of the authors and fresh seawater from the South China Sea. A range of matrix-matched Alfa-S standard solutions and ammonium sulfate solutions was used to investigate the matrix (salinity) effect (matrix was added in the form of NaCl). A seawater sample was used to confirm the reliability of the method. Using matrix-matched (salinity-matched) Alfa-S as the working standard, the measured δ(34)S value of AS (-6.73 ± 0.09‰) was consistent with the reference value (-6.78 ± 0.07‰) within the uncertainty, suggesting that this method could be recommended for the measurement of water samples without prior chemical purification. The δ(34)S value determination for the unpurified seawater also yielded excellent results (21.03 ± 0.18‰) that are consistent with the reference value (20.99‰), thus confirming the feasibility of the technique. The data and the results indicate that it is feasible to use MC-ICP-MS and matrix-matched working standards to measure the sulfur isotopic compositions of water samples directly without chemical purification. In comparison with the existing MC-ICP-MS techniques, the new method is better for directly measuring δ(34)S values in water samples with complex matrices; therefore, it can

  7. A high performance liquid chromatography fingerprinting and ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry chemical profiling approach to rapidly find characteristic chemical markers for quality evaluation of dispensing granules, a case study on Chuanxiong Rhizoma.

    Science.gov (United States)

    Zhang, Xiao-Lin; Liu, Li-Fang; Zhu, Ling-Ying; Bai, Ying-Jia; Mao, Qian; Li, Song-Lin; Chen, Shi-Lin; Xu, Hong-Xi

    2014-01-01

    A high performance liquid chromatography-photodiode array detector (HPLC-PDA) fingerprinting and ultra high performance liquid chromatography-photodiode array detector coupled with quadrupole time-of-flight mass spectrometry (UHPLC-PDA-QTOF-MS/MS) based chemical profiling approach was developed to rapidly find characteristic chemical markers for quality control of dispensing granules, taking Chuanxiong Rhizoma (CR) as a model herb. Firstly, CR crude drugs, their traditional decoctions and CR dispensing granules were analyzed by HPLC-PDA to rapidly establish the fingerprints and thereby generate the simulative median chromatograms of CR crude drugs, decoctions and dispensing granules, and by comparing the simulative median chromatograms, major characteristic peaks of CR decoctions and dispensing granules could be determined. Secondary, UHPLC-PDA-QTOF-MS/MS was used to identify the major characteristic peaks of CR decoctions and dispensing granules. The identities of three major peaks were elucidated and confirmed to be ferulic acid (1), senkyunolide I (2) and senkyunolide H (3) by comparing the mass/UV spectra and retention times with that of the reference compounds. Thirdly, an HPLC-PDA method was validated to quantify the three characteristic components in commercial CR dispensing granules. The average contents of ferulic acid and senkyunolide H were found to be less than 1.0mg/g, whereas that of senkyunolide I was 4.40mg/g in CR dispensing granules, which indicated that senkyunolide I might be chosen as a suitable quantitative marker, while ferulic acid and senkyunolide H as qualitative markers for the quality evaluation of CR dispensing granules. It is suggested that this newly established approach could be used to practically and rapidly find suitable marker compounds for quality control of dispensing granules derived from other medicinal herbs. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Termination of light-water reactor core-melt accidents with a chemical core catcher: the core-melt source reduction system (COMSORS)

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, C.W.; Parker, G.W.; Rudolph, J.C.; Osborne-Lee, I.W. [Oak Ridge National Lab., TN (United States); Kenton, M.A. [Dames and Moore, Westmont, IL (United States)

    1996-09-01

    The Core-Melt Source Reduction System (COMSORS) is a new approach to terminate light-water reactor core melt accidents and ensure containment integrity. A special dissolution glass is placed under the reactor vessel. If core debris is released onto the glass, the glass melts and the debris dissolves into the molten glass, thus creating a homogeneous molten glass. The molten glass, with dissolved core debris, spreads into a wide pool, distributing the heat for removal by radiation to the reactor cavity above or by transfer to water on top of the molten glass. Expected equilibrium glass temperatures are approximately 600 degrees C. The creation of a low-temperature, homogeneous molten glass with known geometry permits cooling of the glass without threatening containment integrity. This report describes the technology, initial experiments to measure key glass properties, and modeling of COMSORS operations.

  9. Quantum-chemical estimation of outersphere cations influence on charge transfer at the NbF{sub 7}{sup 2-} reduction. Pt. 1. Electronic structure of complexes

    Energy Technology Data Exchange (ETDEWEB)

    Soloviev, Veniamin V.; Chernenko, Lyudmila A. [Poltava National Technical Univ., Poltava (Ukraine); Kremenetsky, Vyacheslav G.; Kuznetsov, Sergey A. [Inst. of Chemistry, Kola Science Centre RAS Apatity Murmansk region (Russian Federation)

    2010-03-15

    Quantum-chemical calculations of the parameters of the nM{sup +} . NbF{sub 7}{sup 2-} type particles, where M stands for Na, K, Cs; q = 2,3 and n = 0-7 have been performed. Within the framework of this approximation, compositions for the most stable particles in molten salts were obtained. It is shown that electron transfer onto the particle results in a different redistribution of the electron density with the Na and K-particles on one hand and Cs-containing particles on the other hand. Energies and some other characteristics of the electron structure and particle geometry were determined depending on the n and M values. (orig.)

  10. Enhancement of flexural stress and reduction of surface roughness through changes in gas concentrations during high-speed chemical dry thinning of silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.J. [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Lee, N.-E., E-mail: nelee@skku.edu [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2013-11-29

    Three-dimensional packaging using through silicon via of ultra-thin Si wafers requires very low residual stress. In this study, the effects of additive gases on root-mean-squared (RMS) surface roughness and flexural stress of Si wafers thinned by the high-speed chemical dry etching (CDE) process were investigated. Direct injection of Ar with NO gases into the reactor during the supply of F radicals from NF{sub 3} remote plasmas was effective in increasing the Si wafer thinning rate and in reducing significant surface roughness. Reduced RMS surface roughness of the thinned Si wafer resulted in high flexural stress. The additional injection of N{sub 2} gas further decreased the surface roughness of the thinned Si wafer and, in turn, increased the flexural stress of the thinned wafers. By adjusting the Ar flow and Q ratio, Q(N{sub 2}) = N{sub 2}/(N{sub 2} + NO), Si wafer thinning rates as high as 23 μm/min and RMS surface roughnesses as small as 10 nm were obtained. Furthermore, it was found that the surface roughness is a critical factor affecting the flexural stress of the thinned Si wafer. These results indicate that the high-speed CDE process using F radicals and directly injected NO/Ar/N{sub 2} gases can be applied to ultra-thin Si wafer thinning with controlled RMS surface roughness and low residual stress. - Highlights: • Chemical dry etching of Si wafers affected by N{sub 2}/(N{sub 2} + NO) flow ratio. • Increasing the flow ratio decreased the thinning rate and surface temperature. • Si wafer thinning rate as high as 23 mm/ min was obtained. • Root mean square surface roughness value drastically decreased from 91 to 1.21 nm. • The strength value of flexural stress increased from 162 to 756 MPa.

  11. Capacitive chemical sensor

    Science.gov (United States)

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  12. Effect of chemical functionalization on the electrochemical properties of conducting polymers. Modification of polyaniline by diazonium ion coupling and subsequent reductive degradation

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, Diego F.; Rivarola, Claudia R.; Miras, Maria C. [Departamento de Quimica, Universidad Nacional de Rio Cuarto, Ruta Nacional 8, Km 601, X5804ZAB, Rio Cuarto, Cordoba (Argentina); Barbero, Cesar A., E-mail: cbarbero@exa.unrc.edu.a [Departamento de Quimica, Universidad Nacional de Rio Cuarto, Ruta Nacional 8, Km 601, X5804ZAB, Rio Cuarto, Cordoba (Argentina)

    2011-04-01

    The electrochemical properties of polyaniline (PANI) can be altered by coupling the polymer with aryldiazonium ions. The ions are synthesized by diazotization of aromatic primary amines (1-aminoanthraquinone, sulphadiazine and 4-cyanoaniline) bearing functional groups which are then linked to the polyaniline backbone. All materials produced are electroactive, suggesting that the reaction involves coupling of the diazonium ion with the aromatic rings and not nucleophilic substitution by the aminic nitrogen of PANI on the aryl cations. The electrochemical properties of the modified polymers are different to those of PANI, likely due to electronic and steric effects of the attached groups. Reductive degradation of the azo linkages, using dithionite ion, removes the attached moieties leaving primary amino groups attached to the polyaniline backbone. In that way, the effect of the attached groups on the electrochemical properties of PANI is eliminated. FTIR spectroscopy measurement of the different polymers supports the proposed mechanism. Using the method a polymer containing redox (anthraquinone) groups, which could be used for charge storage, is obtained. Additionally a material containing sulphadiazine moieties, which can be released in vivo by bacterial activity, is also produced. The molecule is a well-known sulfa drug with bacteriostatic activity. The reaction sequence seems to be of general application to modify polyanilines, by attaching functional groups, and then to produce a PANI backbone bearing primary amino groups. Evidence is presented on the kinetic control of attached group removal.

  13. Theoretical study of oxidation-reduction reaction of Fe2O3 supported on MgO during chemical looping combustion

    Science.gov (United States)

    Qin, Wu; Chen, Qiuluan; Wang, Yang; Dong, Changqing; Zhang, Junjiao; Li, Wenyan; Yang, Yongping

    2013-02-01

    We applied density-functional theory (DFT) in periodic system to investigate the two reactions (CO + Fe2O3/MgO → CO2 + Fe2O2/MgO, O2 + Fe2O2/MgO → O + Fe2O3/MgO) in chemical looping combustion system. While Fe2O3 was supported on MgO(1 0 0) surface Fe2O3 gathered together to form a cluster shape on MgO(1 0 0), denoted as Fe2O3/MgO, where the Fe2O3 was activated by MgO(1 0 0). Then CO interacted with Fe2O3/MgO and carbonate generated during a stepwise reaction with the calculated maximum barrier energy of 0.95 eV, far less than that of the reaction between CO and the pure Fe2O3 cluster (2.59 eV). CO was oxidized by Fe2O3/MgO and then Fe2O3/MgO transformed into the reduced state Fe2O2/MgO, corresponding to the reaction in the fuel reactor in the CLC system. Then the breaking of the adsorbed O2 molecule on Fe2O2/MgO made an O atom bind to a Fe site with the barrier energy of 0. 20 eV, which played as the key step for the oxidizing of Fe2O2/MgO by O2 into Fe2O3/MgO, corresponding to the reaction in the air reactor in the CLC system.

  14. Rapid Prototyping

    Science.gov (United States)

    1999-01-01

    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  15. Rapid Sterilization of Escherichia coli by Solution Plasma Process

    Science.gov (United States)

    Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

    2012-12-01

    Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

  16. Fast low-temperature plasma reduction of monolayer graphene oxide at atmospheric pressure

    Science.gov (United States)

    Bodik, Michal; Zahoranova, Anna; Micusik, Matej; Bugarova, Nikola; Spitalsky, Zdenko; Omastova, Maria; Majkova, Eva; Jergel, Matej; Siffalovic, Peter

    2017-04-01

    We report on an ultrafast plasma-based graphene oxide reduction method superior to conventional vacuum thermal annealing and/or chemical reduction. The method is based on the effect of non-equilibrium atmospheric-pressure plasma generated by the diffuse coplanar surface barrier discharge in proximity of the graphene oxide layer. As the reduction time is in the order of seconds, the presented method is applicable to the large-scale production of reduced graphene oxide layers. The short reduction times are achieved by the high-volume power density of plasma, which is of the order of 100 W cm-3. Monolayers of graphene oxide on silicon substrate were prepared by a modified Langmuir-Schaefer method and the efficient and rapid reduction by methane and/or hydrogen plasma was demonstrated. The best results were obtained for the graphene oxide reduction in hydrogen plasma, as verified by x-ray photoelectron spectroscopy and Raman spectroscopy.

  17. Rapid Determination of Optimal Conditions in a Continuous Flow Reactor Using Process Analytical Technology

    Directory of Open Access Journals (Sweden)

    Michael F. Roberto

    2013-12-01

    Full Text Available Continuous flow reactors (CFRs are an emerging technology that offer several advantages over traditional batch synthesis methods, including more efficient mixing schemes, rapid heat transfer, and increased user safety. Of particular interest to the specialty chemical and pharmaceutical manufacturing industries is the significantly improved reliability and product reproducibility over time. CFR reproducibility can be attributed to the reactors achieving and maintaining a steady state once all physical and chemical conditions have stabilized. This work describes the implementation of a smart CFR with univariate physical and multivariate chemical monitoring that allows for rapid determination of steady state, requiring less than one minute. Additionally, the use of process analytical technology further enabled a significant reduction in the time and cost associated with offline validation methods. The technology implemented for this study is chemistry and hardware agnostic, making this approach a viable means of optimizing the conditions of any CFR.

  18. Examination of surface phenomena of V₂O₅ loaded on new nanostructured TiO₂ prepared by chemical vapor condensation for enhanced NH₃-based selective catalytic reduction (SCR) at low temperatures.

    Science.gov (United States)

    Cha, Woojoon; Yun, Seong-Taek; Jurng, Jongsoo

    2014-09-07

    In this article, we describe the investigation and surface characterization of a chemical vapor condensation (CVC)-TiO2 support material used in a V2O5/TiO2 catalyst for enhanced selective catalytic reduction (SCR) activity and confirm the mechanism of surface reactions. On the basis of previous studies and comparison with a commercial TiO2 catalyst, we examine four fundamental questions: first, the reason for increased surface V(4+) ion concentrations; second, the origin of the increase in surface acid sites; third, a basis for synergistic influences on improvements in SCR activity; and fourth, a reason for improved catalytic activity at low reaction temperatures. In this study, we have cited the result of SCR with NH3 activity for removing NOx and analyzed data using the reported result and data from previous studies on V2O5/CVC-TiO2 for the SCR catalyst. In order to determine the properties of suitable CVC-TiO2 surfaces for efficient SCR catalysis at low temperatures, CVC-TiO2 specimens were prepared and characterized using techniques such as XRD, BET, HR-TEM, XPS, FT-IR, NH3-TPD, photoluminescence (PL) spectroscopy, H2-TPR, and cyclic voltammetry. The results obtained for the CVC-TiO2 materials were also compared with those of commercial TiO2.

  19. The contribution of reduction in malaria as a cause of rapid decline of under-five mortality: evidence from the Rufiji Health and Demographic Surveillance System (HDSS) in rural Tanzania.

    Science.gov (United States)

    Kanté, Almamy M; Nathan, Rose; Helleringer, Stéphane; Sigilbert, Mrema; Levira, Francis; Masanja, Honorati; de Savigny, Don; Abdulla, Salim; Phillips, James F

    2014-05-10

    Under-five mortality has been declining rapidly in a number of sub-Saharan African settings. Malaria-related mortality is known to be a major component of childhood causes of death and malaria remains a major focus of health interventions. The paper explored the contribution of malaria relative to other specific causes of under-five deaths to these trends. This paper uses longitudinal demographic surveillance data to examine trends and causes of death of under-five mortality in Rufiji, whose population has been followed for over nine years (1999-2007). Causes of death, determined by the verbal autopsy technique, are analysed with Arriaga's decomposition method to assess the contribution of declining malaria-related mortality relative to other causes of death as explaining a rapid decline in overall childhood mortality. Over the 1999-2007 period, under-five mortality rate in Rufiji declined by 54.3%, from 33.3 to 15.2 per 1,000 person-years. If this trend is sustained, Rufiji will be a locality that achieves MDG4 target. Although hypotrophy at birth remained the leading cause of death for neonates, malaria remains as the leading cause of death for post-neonates followed by pneumonia. However, declines in malaria death rates accounted for 49.9% of the observed under-five mortality decline while all perinatal causes accounted for only 19.9%. To achieve MDG 4 in malaria endemic settings, health programmes should continue efforts to reduce malaria mortality and more efforts are also needed to improve newborn survival.

  20. Handling Biological Complexity Using Kron Reduction

    NARCIS (Netherlands)

    Jayawardhana, Bayu; Rao, Shodhan; Sikkema, Ward; Bakker, Barbara; Camlibel, Kanat; Julius, Agung; Pasumarthy, Ramkrishna; Scherpen, Jacquelien

    2015-01-01

    We revisit a model reduction method for detailed-balanced chemical reaction networks based on Kron reduction on the graph of complexes. The resulting reduced model preserves a number of important properties of the original model, such as, the kinetics law and identity of the chemical species. For

  1. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  2. Nitrate reduction

    Science.gov (United States)

    Dziewinski, Jacek J.; Marczak, Stanislaw

    2000-01-01

    Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.

  3. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Use of Laser Engineered Net Shaping for Rapid Manufacturing of Dies with Protective Coatings and Improved Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Brevick, Jerald R. [Ohio State University

    2014-06-13

    In the high pressure die casting process, molten metal is introduced into a die cavity at high pressure and velocity, enabling castings of thin wall section and complex geometry to be obtained. Traditional die materials have been hot work die steels, commonly H13. Manufacture of the dies involves machining the desired geometry from monolithic blocks of annealed tool steel, heat treating to desired hardness and toughness, and final machining, grinding and polishing. The die is fabricated with internal water cooling passages created by drilling. These materials and fabrication methods have been used for many years, however, there are limitations. Tool steels have relatively low thermal conductivity, and as a result, it takes time to remove the heat from the tool steel via the drilled internal water cooling passages. Furthermore, the low thermal conductivity generates large thermal gradients at the die cavity surfaces, which ultimately leads to thermal fatigue cracking on the surfaces of the die steel. The high die surface temperatures also promote the metallurgical bonding of the aluminum casting alloy to the surface of the die steel (soldering). In terms of process efficiency, these tooling limitations reduce the number of die castings that can be made per unit time by increasing cycle time required for cooling, and increasing downtime and cost to replace tooling which has failed either by soldering or by thermal fatigue cracking (heat checking). The objective of this research was to evaluate the feasibility of designing, fabricating, and testing high pressure die casting tooling having properties equivalent to H13 on the surface in contact with molten casting alloy - for high temperature and high velocity molten metal erosion resistance – but with the ability to conduct heat rapidly to interior water cooling passages. A layered bimetallic tool design was selected, and the design evaluated for thermal and mechanical performance via finite element analysis. H13 was

  4. Chemical exchange program analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Waffelaert, Pascale

    2007-09-01

    will not only reduce the quantity of unneeded chemicals and the amount spent on new purchases, but will also avoid disposal costs. If SNL/NM were to realize a 5 percent reduction in chemical inventory and a 10 percent reduction in disposal of unused chemicals the total savings would be $189, 200 per year.

  5. Chemical bond fundamental aspects of chemical bonding

    CERN Document Server

    Frenking, Gernot

    2014-01-01

    This is the perfect complement to ""Chemical Bonding - Across the Periodic Table"" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemica

  6. Oscillatory flow chemical reactors

    OpenAIRE

    Slavnić Danijela S.; Bugarski Branko M.; Nikačević Nikola M.

    2014-01-01

    Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions) is a transition from batch to continuous processes. However, the reactions of interests for the mentioned indust...

  7. A new digestion and chemical separation technique for rapid and highly reproducible determination of Lu/Hf and Hf isotope ratios in geological materials by mc-ICP-MS

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Baker, J.A.; Ulfbeck, D.

    2003-01-01

    A new digestion procedure and chemical separation technique has been developed for measurement of Lu/Hf and Hf isotope ratios that does not require high-pressure bombs or use of HF or HClO acids. Samples are digested in dilute HCl or HNO after flux-fusion at 1100 °C in the presence of lithium...

  8. Rich Reduction

    DEFF Research Database (Denmark)

    Niebuhr, Oliver

    2016-01-01

    Managing and, ideally, explaining phonetic variation has ever since been a key issue in the speech sciences. In this context, the major contribution of Lindblom's H&H theory was to replace the futile search for invariance by an explainable variance based on the tug-of-war metaphor. Recent empirical...... evidence on articulatory prosodies and the involvement of reduction in conveying communication functions both suggest the next steps along the line of argument opened up by Lindblom. Specifically, we need to supplement Lindblom's explanatory framework and revise the speaker-listener conflict that lies...... at the heart of the tug-of-war metaphor. The author's suggestion would be to "offshore" the tug-of-war metaphor and replace it by the ocean metaphor of Bolinger (1964), with the ups and downs at the surface of the ocean representing the speaker's variation along the hypo-hyper scale and wavelength...

  9. The Nature of Reduction in Space Weathering

    Science.gov (United States)

    McKay, D. S.; Allen, C. C.

    1993-07-01

    Space weathering is a broad term that includes a number of complex effects of the exposure of materials to the environment of space. The processes that drive space weathering include micrometeorite impact, radiation from the Sun and cosmic rays, and exposure to the vacuum of space. One of the important effects caused by these processes is the tendency for chemical reduction of oxide and silicate materials (including glasses), with accompanying loss of oxygen and production of reduced metal. Such chemical reduction and accompanying metal production may have an important influence on the chemistry of the outermost volume of individual grains as well as on the optical properties of this material. Hapke [1] discussed five processes that have been suggested for producing submicroscopic iron metal in the lunar soil: (1) shock reduction, (2) heating in a thermal blanket in vacuum, (3) shock heating of solar-wind-impregnated grains, (4) coatings deposited by solar wind sputtering, and (5) coatings deposited by impact vaporization. As noted by Hapke, "Processes (1) and (2) have been refuted by laboratory experiments. Processes (4) and (5) have produced submicroscopic iron metal in laboratory simulations. Although no experiments have been done to simulate process (3), it is widely accepted." We have been performing experimental reduction of simulated and actual lunar materials [2-5] and have shown that, under conditions of exposure to hydrogen at elevated temperatures, reduction of FeO readily occurs in ilmenite and lunar composition glass, and occurs at a slower rate in pyroxene and olivine. Even plagioclase feldspar containing minor FeO is readily reduced with formation of metallic iron blebs on surfaces [4]. A comparison of natural lunar samples to hydrogen-reduced samples or simulants in which we are searching for reduction evidence in various soil phases is underway. Preliminary data for mature soils show, in agreement with earlier results, that reduced iron produced in

  10. Exceptional Reductions

    CERN Document Server

    Marrani, Alessio; Riccioni, Fabio

    2011-01-01

    Starting from basic identities of the group E8, we perform progressive reductions, namely decompositions with respect to the maximal and symmetric embeddings of E7xSU(2) and then of E6xU(1). This procedure provides a systematic approach to the basic identities involving invariant primitive tensor structures of various irreprs. of finite-dimensional exceptional Lie groups. We derive novel identities for E7 and E6, highlighting the E8 origin of some well known ones. In order to elucidate the connections of this formalism to four-dimensional Maxwell-Einstein supergravity theories based on symmetric scalar manifolds (and related to irreducible Euclidean Jordan algebras, the unique exception being the triality-symmetric N = 2 stu model), we then derive a fundamental identity involving the unique rank-4 symmetric invariant tensor of the 0-brane charge symplectic irrepr. of U-duality groups, with potential applications in the quantization of the charge orbits of supergravity theories, as well as in the study of mult...

  11. Commercial aspects of rapid thermal processing (RTP)

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R.G.; Huffman, D.R. [Ensyn Technologies Inc., Greely, ON (Canada)

    1996-12-31

    In its broadest sense, Rapid Thermal Processing (RTP{sup TM}) covers the conversion of all types of carbonaceous materials to liquid fuels, high quality fuel gases, and chemicals. Scientifically, it is based on the general premise that products which result from the extremely rapid application of heat to a given feedstock are inherently more valuable than those which are produced when heat is applied much more slowly over longer periods of processing time. Commercial RTP{sup TM} activities (including the actual implementation in the market as well as the short-term R and D initiatives) are much narrower in scope, and are focused on the production of high yields of light, non-tarry liquids (i.e. `bio-crude`) from biomass for fuel and chemical markets. Chemicals are of significant interest from an economical point of view since they typically have a higher value than fuel products. Liquid fuels are of interest for many reasons: (1) Liquid fuels do not have to be used immediately after production, such as is the case with hot combustion gases or combustible gases produced via gasification. This allows the decoupling of fuel production from the end-use (ie. the conversion of fuel to energy). (2) The higher energy density of liquid fuels vs. that of fuel gases and solid biomass results in a large reduction in the costs associated with storage and transportation. (3) The costs to retrofit an existing gas or oil fired combustion system are much lower than replacement with a solid fuel combustor. (4) In general, liquid fuel combustion is much more efficient, controllable, and cleaner than the combustion of solid fuels. (5) The production of liquid `bio-crude` permits the removal of ash from the biomass prior to combustion or other end-use applications. (6) Gas or liquid fuel-fired diesel or turbine engines cannot operate commercially on solid fuels. Although wood represents the biomass which is of principal commercial interest (including a vast array of wood residues

  12. Data Reduction and Rapid Analysis of Hyperspectral Data Sets Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hyperspectral sensors offer great opportunities for increasingly sensitive automated target recognition (ATR) systems though a common problem is the lack of...

  13. Green Tea Cultivation at the Northern Limit of Economical Cultivation—Effects of the Reduction of Chemical Fertilizer on the Plant Growth and the Quality of the First Crop Tea

    National Research Council Canada - National Science Library

    Fu, Jieqi; Hoshino, Koichi; Hirai, Hideaki; Kato, Hidemasa

    2010-01-01

      The effects of compost and coated fertilizer nitrogen on the quality of the first crop tea were investigated in order to reduce the application of chemical fertilizer nitrogen (CFN) to tea gardens...

  14. Preliminary comparison of different reduction methods of graphene ...

    Indian Academy of Sciences (India)

    The reduction of graphene oxide (GO) is a promising route to bulk produce graphene-based sheets. Different reduction processes result in reduced graphene oxide (RGO) with different properties. In this paper three reduction methods, chemical, thermal and electrochemical reduction, were compared on three aspects ...

  15. Rapid mixing kinetic techniques.

    Science.gov (United States)

    Martin, Stephen R; Schilstra, Maria J

    2013-01-01

    Almost all of the elementary steps in a biochemical reaction scheme are either unimolecular or bimolecular processes that frequently occur on sub-second, often sub-millisecond, time scales. The traditional approach in kinetic studies is to mix two or more reagents and monitor the changes in concentrations with time. Conventional spectrophotometers cannot generally be used to study reactions that are complete within less than about 20 s, as it takes that amount of time to manually mix the reagents and activate the instrument. Rapid mixing techniques, which generally achieve mixing in less than 2 ms, overcome this limitation. This chapter is concerned with the use of these techniques in the study of reactions which reach equilibrium; the application of these methods to the study of enzyme kinetics is described in several excellent texts (Cornish-Bowden, Fundamentals of enzyme kinetics. Portland Press, 1995; Gutfreund, Kinetics for the life sciences. Receptors, transmitters and catalysis. Cambridge University Press, 1995).There are various ways to monitor changes in concentration of reactants, intermediates and products after mixing, but the most common way is to use changes in optical signals (absorbance or fluorescence) which often accompany reactions. Although absorbance can sometimes be used, fluorescence is often preferred because of its greater sensitivity, particularly in monitoring conformational changes. Such methods are continuous with good time resolution but they seldom permit the direct determination of the concentrations of individual species. Alternatively, samples may be taken from the reaction volume, mixed with a chemical quenching agent to stop the reaction, and their contents assessed by techniques such as HPLC. These methods can directly determine the concentrations of different species, but are discontinuous and have a limited time resolution.

  16. Reduction of bromate by biogenic sulfide produced during microbial sulfur disproportionation.

    Science.gov (United States)

    Chairez, Monserrat; Luna-Velasco, Antonia; Field, Jim A; Ju, Xiumin; Sierra-Alvarez, Reyes

    2010-04-01

    Bromate (BrO(3) (-)) is a carcinogenic contaminant formed during ozonation of waters that contain trace amounts of bromide. Previous research shows that bromate can be microbially reduced to bromide using organic (i.e. acetate, glucose, ethanol) and inorganic (H(2)) electron-donating substrates. In this study, the reduction of bromate by a mixed microbial culture was investigated using elemental sulfur (S(0)) as an electron donor. In batch bioassays performed at 30 degrees C, bromate (0.30 mM) was completely converted to bromide after 10 days and no accumulation of intermediates occurred. Bromate was also reduced in cultures supplemented with thiosulfate and hydrogen sulfide as electron donor. Our results demonstrated that S(0)-disproportionating microorganisms were responsible for the reduction of bromate in cultures spiked with S(0) through an indirect mechanism involving microbial formation of sulfide and subsequent abiotic reduction of bromate by the biogenic sulfide. Confirmation of this mechanism is the fact that bromate was shown to undergo rapid chemical reduction by sulfide (but not S(0) or thiosulfate) in abiotic experiments. Bromate concentrations above 0.30 mM inhibited sulfide formation by S(0)-disproportionating bacteria, leading to a decrease in the rate of bromate reduction. The results suggest that biological formation of sulfide from by S(0) disproportionation could support the chemical removal of bromate without having to directly use sulfide as a reagent.

  17. Chemical Synthesis of Copper Nanoparticles

    OpenAIRE

    Hamid Reza Ghorbani

    2014-01-01

    Metal nanoparticles have attracted considerable interest particularly because of the size dependence of physical and chemical properties and its enormous technological potential. Among different metal nanoparticles, copper nanoparticles have attracted great attention because copper is one of the most key metals in new technology. Chemical methods are used to synthesize copper nanoparticles and among them chemical reduction is the most frequently applied method for the preparation of stable, c...

  18. The Cryo-Thermochromatographic Separator (CTS) A new rapid separation and alpha-detection system for on-line chemical studies of highly volatile osmium and hassium (Z=108) tetroxides

    CERN Document Server

    Kirbach, U W; Gregorich, K E; Lee, D M; Ninov, V; Omtvedt, J P; Patin, J B; Seward, N K; Strellis, D A; Sudowe, R; Türler, A; Wilk, P A; Zielinski, P M; Hoffman, D C; Nitsche, H

    2002-01-01

    The Cryo-Thermochromatographic Separator (CTS) was designed and constructed for rapid, continuous on-line separation and simultaneous detection of highly volatile compounds of short-lived alpha-decaying isotopes of osmium and hassium (Hs, Z=108). A flowing carrier gas containing the volatile species is passed through a channel formed by two facing rows of 32 alpha-particle detectors, cooled to form a temperature gradient extending from 247 K at the channel entrance down to 176 K at the exit. The volatile species adsorb onto the SiO sub 2 -coated detector surfaces at a characteristic deposition temperature and are identified by their observed alpha-decay energies. The CTS was tested on-line with OsO sub 4 prepared from sup 1 sup 6 sup 9 sup - sup 1 sup 7 sup 3 Os isotopes produced in sup 1 sup 1 sup 8 sup , sup 1 sup 2 sup 0 Sn( sup 5 sup 6 Fe, 3,4,5n) reactions. An adsorption enthalpy for OsO sub 4 of -40.2+-1.5 kJ/mol on SiO sub 2 was deduced by comparing the measured deposition distribution with Monte Carlo...

  19. Formation of semiquinone radical in the reaction of embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) with reductants as well as oxidants. Characterization by pulse radiolysis and structure investigation by quantum chemical study

    Science.gov (United States)

    Joshi, Ravi; Ghanty, Tapan K.; Mukherjee, Tulsi

    2009-06-01

    Embelin, 2,5-dihydroxy-3-undecyl-1,4-benzoquinone, has two intra-molecular hydrogen bonds between the quinone and hydroquinone groups present on the same ring. Therefore, it is expected to produce semiquinone radical in the oxidation as well reduction reactions. To investigate this aspect, kinetics and mechanism of reduction reactions of embelin have been studied using nanosecond electron pulse radiolysis technique and compared with the oxidation process. Two distinct transients observed in the reduction ( λmax = 450 nm) and the oxidation ( λmax = 410 nm) processes with various free radicals have been characterized and assigned to two different embelin semiquinone radicals on the basis of pulse radiolysis studies. The structures of these transients have been further ascertained using density functional theory with B3LYP functional and 6-31+G(d,p) basis set. Reduction reaction of embelin has been found to produce delocalized semiquinone anion radical. On the other hand, oxidation of embelin is expected to produce several transient species. However, the calculations suggest that oxidation of hydroquinone group is the first step, which is followed by transformation into carbon-centered radical.

  20. SELECTION AND PRELIMINARY EVALUATION OF ALTERNATIVE REDUCTANTS FOR SRAT PROCESSING

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M.; Pickenheim, B.; Peeler, D.

    2009-06-30

    Defense Waste Processing Facility - Engineering (DWPF-E) has requested the Savannah River National Laboratory (SRNL) to perform scoping evaluations of alternative flowsheets with the primary focus on alternatives to formic acid during Chemical Process Cell (CPC) processing. The reductants shown below were selected for testing during the evaluation of alternative reductants for Sludge Receipt and Adjustment Tank (SRAT) processing. The reductants fall into two general categories: reducing acids and non-acidic reducing agents. Reducing acids were selected as direct replacements for formic acid to reduce mercury in the SRAT, to acidify the sludge, and to balance the melter REDuction/OXidation potential (REDOX). Non-acidic reductants were selected as melter reductants and would not be able to reduce mercury in the SRAT. Sugar was not tested during this scoping evaluation as previous work has already been conducted on the use of sugar with DWPF feeds. Based on the testing performed, the only viable short-term path to mitigating hydrogen generation in the CPC is replacement of formic acid with a mixture of glycolic and formic acids. An experiment using glycolic acid blended with formic on an 80:20 molar basis was able to reduce mercury, while also targeting a predicted REDuction/OXidation (REDOX) of 0.2 expressed as Fe{sup 2+}/{Sigma}Fe. Based on this result, SRNL recommends performing a complete CPC demonstration of the glycolic/formic acid flowsheet followed by a design basis development and documentation. Of the options tested recently and in the past, nitric/glycolic/formic blended acids has the potential for near term implementation in the existing CPC equipment providing rapid throughput improvement. Use of a non-acidic reductant is recommended only if the processing constraints to remove mercury and acidify the sludge acidification are eliminated. The non-acidic reductants (e.g. sugar) will not reduce mercury during CPC processing and sludge acidification would

  1. Principles of chemical kinetics

    CERN Document Server

    House, James E

    2007-01-01

    James House's revised Principles of Chemical Kinetics provides a clear and logical description of chemical kinetics in a manner unlike any other book of its kind. Clearly written with detailed derivations, the text allows students to move rapidly from theoretical concepts of rates of reaction to concrete applications. Unlike other texts, House presents a balanced treatment of kinetic reactions in gas, solution, and solid states. The entire text has been revised and includes many new sections and an additional chapter on applications of kinetics. The topics covered include quantitative rela

  2. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  3. Chemical genomics in plant biology.

    Science.gov (United States)

    Sadhukhan, Ayan; Sahoo, Lingaraj; Panda, Sanjib Kumar

    2012-06-01

    Chemical genomics is a newly emerged and rapidly progressing field in biology, where small chemical molecules bind specifically and reversibly to protein(s) to modulate their function(s), leading to the delineation and subsequent unravelling of biological processes. This approach overcomes problems like lethality and redundancy of classical genetics. Armed with the powerful techniques of combinatorial synthesis, high-throughput screening and target discovery chemical genomics expands its scope to diverse areas in biology. The well-established genetic system of Arabidopsis model allows chemical genomics to enter into the realm of plant biology exploring signaling pathways of growth regulators, endomembrane signaling cascades, plant defense mechanisms and many more events.

  4. Rapid Prototyping Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC Rapid Prototyping (RP) Laboratory was established in December 1992 to provide low cost RP capabilities to the ARDEC engineering community. The Stratasys,...

  5. Reduction of nitrate and nitrite salts under hydrothermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Foy, B.R.; Dell`Orco, P.C.; Wilmanns, E.; McInroy, R.; Ely, J.; Robinson, J.M.; Buelow, S.J.

    1994-10-01

    The feasibility of reducing nitrate/nitrite salts under hydrothermal conditions for the treatment of aqueous mixed wastes stored in the underground tanks at the Department of Energy site at Hanford, Washington was studied. The reduction of nitrate and nitrite salts by reaction with EDTA using a tank waste simulant was examined at temperatures between 623K and 800K and pressures between 0.6 and 1.2 kbar. Continuous flow reactors were used to determine kinetics and products of reactions. All reactions were studied under pressures high enough to produce single phase conditions. The reactions are rapid, go to completion in less than a minute, and produce simple products, such as carbonate, nitrogen, and nitrous oxide gases. The experimental results demonstrate the ability of chemical reactions under hydrothermal conditions to reduce the nitrate and nitrite salts and destroy organic compounds in the waste mixtures.

  6. Simultaneous and rapid determination of multiple component concentrations in a Kraft liquor process stream

    Science.gov (United States)

    Li, Jian [Marietta, GA; Chai, Xin Sheng [Atlanta, GA; Zhu, Junyoung [Marietta, GA

    2008-06-24

    The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples. The inventive method can be used in Kraft pulping operations to control white liquor causticizing efficiency, sulfate reduction efficiency in green liquor, oxidation efficiency for oxidized white liquor and the active and effective alkali charge to kraft pulping operations.

  7. Turnbull - Early Detection and Rapid Response Team 2007

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Biocontrol agents and chemicals to facilitate the rapid response phase of the project will be purchased and applied and a Washington Service Corps AmeriCorps member...

  8. Turnbull - Early Detection and Rapid Response Team 2010

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Funding from this grant will allow for the purchase of biocontrol agents and chemicals to facilitate the rapid response phase of the project and to provide funds to...

  9. Turnbull - Early Detection and Rapid Response Team 2008

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Funding from this grant will allow for the purchase of biocontrol agents and chemicals to facilitate the rapid response phase of the project and to provide match for...

  10. [Chemical weapons and chemical terrorism].

    Science.gov (United States)

    Nakamura, Katsumi

    2005-10-01

    Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary.

  11. Chemical and Electrochemical Properties of La0.58Sr0.4Fe0.8Co0.2O3-δ (LSCF) Thin Films upon Oxygen Reduction and Evolution Reactions

    DEFF Research Database (Denmark)

    Pitscheider, Simon; Machala, Michael; Guan, Zixuan

    conditions. In particular, NAP-XPS studies of the surface chemistry evolution under operation, as well as the correlation between surface potential changes in relation to the applied overpotential are addressed, in an attempt to determine the real driving force for the oxygen reactions.For this purpose, thin......The Oxygen Evolution and Oxygen Reduction Reactions (OER/ORR), occurring at the oxygen electrode of Solid Oxide Cells (SOCs) in the two possible ways of operation, require substantial overpotentials, therefore lowering the operating efficiency of the cells. The reaction mechanisms occurring...

  12. Chemical Composition

    Science.gov (United States)

    May, Willie; Cavanagh, Richard; Turk, Gregory; Winchester, Michael; Travis, John; Smith, Melody; Derose, Paul; Choquette, Steven; Kramer, Gary; Sieber, John; Greenberg, Robert; Lindstrom, Richard; Lamaze, George; Zeisler, Rolf; Schantz, Michele; Sander, Lane; Phinney, Karen; Welch, Michael; Vetter, Thomas; Pratt, Kenneth; Scott, John; Small, John; Wight, Scott; Stranick, Stephan

    Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and nutrition, agriculture, environmental technologies, chemicals and materials, instrumentation, electronics, forensics, energy, and transportation.

  13. Investigation on electrochemical behavior and its catalytic effect on oxygen reduction reaction of 3-Ferrocenyl dihydropyrazole derivative as electron relay

    Science.gov (United States)

    Zeng, Han; Huo, Wen-Shan; Zhao, Shu-Xian; Zhang, Yu-He

    2017-11-01

    Amino group surface tailored multi-wall carbon nano-tubes were covalently tethered to the gold disk electrode and Laccase molecules were covalently coupled to nano-tubes to prepare Lac-based electrode. Derivative of 3-ferrocenyl dihydropyrazole (FDPFFP) was proposed to be electron mediator for mediated oxygen reduction reaction. Investigation in electro-chemical behavior and catalytic performance to enzymatic reaction of FDPFFP indicated that it displayed quasi-reversible characteristics of electro-chemical reaction with rapid dynamics of electron shuttle and had apparent catalytic effect in oxygen reduction (onset potential for catalysis at 450 mV vs NHE). This enzymatic catalysis was restrained by the step in diffusion of substrate.

  14. Chemical Debridement of Burns

    Science.gov (United States)

    Levenson, Stanley M.; Kan, Dorinne; Gruber, Charles; Crowley, Leo V.; Lent, Richard; Watford, Alvin; Seifter, Eli

    1974-01-01

    The development of effective, non-toxic (local and systemic) methods for the rapid chemical (enzymatic and non-enzymatic) debridement of third degree burns would dramatically reduce the morbidity and mortality of severely burned patients. Sepsis is still the major cause of death of patients with extensive deep burns. The removal of the devitalized tissue, without damage to unburned skin or skin only partially injured by burning, and in ways which would permit immediate (or very prompt) skin grafting, would lessen substantially the problems of sepsis, speed convalescence and the return of these individuals to society as effective human beings, and would decrease deaths. The usefulness and limitations of surgical excision for patients with extensive third degree burns are discussed. Chemical debridement lends itself to complementary use with surgical excision and has the potential advantage over surgical excision in not requiring anesthesia or a formal surgical operation. The authors' work with the chemical debridement of burns, in particular the use of Bromelain, indicates that this approach will likely achieve clinical usefulness. The experimental studies indicate that rapid controlled debridement, with minimal local and systemic toxicity, is possible, and that effective chemotherapeutic agents may be combined with the Bromelain without either interfering with the actions of the other. The authors believe that rapid (hours) debridement accomplished by the combined use of chemical debriding and chemotherapeutic agents will obviate the possibility of any increase in infection, caused by the use of chemical agents for debridement, as reported for Paraenzyme21 and Travase.39,48 It is possible that the short term use of systemic antibiotics begun just before and continued during, and for a short time after, the rapid chemical debridement may prove useful for the prevention of infection, as appears to be the case for abdominal operations of the clean-contaminated and

  15. Chemical oceanography

    National Research Council Canada - National Science Library

    Millero, F.J

    1996-01-01

    Chemical Oceanography presents a comprehensive examination of the chemistry of oceans through discussions of such topics as descriptive physical oceanography, the composition of seawater and the major...

  16. Rapid Response in Psychological Treatments for Binge-Eating Disorder

    Science.gov (United States)

    Hilbert, Anja; Hildebrandt, Thomas; Agras, W. Stewart; Wilfley, Denise E.; Wilson, G. Terence

    2015-01-01

    Objective Analysis of short- and long-term effects of rapid response across three different treatments for binge-eating disorder (BED). Method In a randomized clinical study comparing interpersonal psychotherapy (IPT), cognitive-behavioral guided self-help (CBTgsh), and behavioral weight loss (BWL) treatment in 205 adults meeting DSM-IV criteria for BED, the predictive value of rapid response, defined as ≥ 70% reduction in binge-eating by week four, was determined for remission from binge-eating and global eating disorder psychopathology at posttreatment, 6-, 12-, 18-, and 24-month follow-up. Results Rapid responders in CBTgsh, but not in IPT or BWL, showed significantly greater rates of remission from binge-eating than non-rapid responders, which was sustained over the long term. Rapid and non-rapid responders in IPT and rapid responders in CBTgsh showed a greater remission from binge-eating than non-rapid responders in CBTgsh and BWL. Rapid responders in CBTgsh showed greater remission from binge-eating than rapid responders in BWL. Although rapid responders in all treatments had lower global eating disorder psychopathology than non-rapid responders in the short term, rapid responders in CBTgsh and IPT were more improved than those in BWL and non-rapid responders in each treatment. Rapid responders in BWL did not differ from non-rapid responders in CBTgsh and IPT. Conclusions Rapid response is a treatment-specific positive prognostic indicator of sustained remission from binge-eating in CBTgsh. Regarding an evidence-based stepped care model, IPT, equally efficacious for rapid and non-rapid responders, could be investigated as a second-line treatment in case of non-rapid response to first-line CBTgsh. PMID:25867446

  17. Rapid Airplane Parametric Input Design (RAPID)

    Science.gov (United States)

    Smith, Robert E.

    1995-01-01

    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool

  18. Effects of bodyweight reduction on sports performance.

    Science.gov (United States)

    Fogelholm, M

    1994-10-01

    Athletes reduce bodyweight for several reasons: to compete in a lower weight class; to improve aesthetic appearance; or to increase physical performance. Rapid bodyweight reduction (dehydration in 12 to 96 hours), typically with fluid restriction and increased exercise, is used by athletes competing in weight-class events. Gradual bodyweight reduction (over > 1 week) is usually achieved by cutting energy intake to 75 to 130 kJ/kg/day. An intake of 100 kJ/kg/day results in a weekly bodyweight loss of roughly 1kg. Aerobic endurance capacity decreases after rapid bodyweight reduction, but might increase after gradual bodyweight reduction. Maximal oxygen uptake (VO2max) measured as L/min is unchanged or decreased after bodyweight loss, but VO2max measured as ml/kg/min may increase after gradual bodyweight reduction. Anaerobic performance and muscle strength are typically decreased after rapid bodyweight reduction with or without 1 to 3 hours rehydration. When tested after 5 to 24 hours of rehydration, performance is maintained at euhydrated levels. A high carbohydrate diet during bodyweight loss may help in maintaining performance. Anaerobic performance is not affected and strength can increase after gradual bodyweight reduction. Reductions in plasma volume, muscle glycogen content and the buffer capacity of the blood explain decreased performance after rapid bodyweight reduction. During gradual bodyweight loss, slow glycogen resynthesis after training, loss of muscle protein and stress fractures (caused by endocrinological disorders) may affect performance. Athletes' bodyweight goals should be individualised rather than by comparing with other athletes. If the time between weigh-in and competition is < 5 hours, rapid bodyweight reduction should not exceed 4% of bodyweight. If the time interval is longer, a bodyweight reduction < or = 8% might be acceptable. A moderate-energy (100 to 120 kJ/kg/day) and high-carbohydrate (60 to 70% of total energy intake) diet is

  19. Chemical intolerance

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Andersson, Linus; Nordin, Steven

    2015-01-01

    Chemical intolerance (CI) is a term used to describe a condition in which the sufferer experiences a complex array of recurrent unspecific symptoms attributed to low-level chemical exposure that most people regard as unproblematic. Severe CI constitutes the distinguishing feature of multiple...

  20. Chemical modification

    Science.gov (United States)

    R. M. Rowell

    2004-01-01

    Wood is a hygroscopic resource that was designed to perform, in nature, in a wet environment. Nature is programmed to recycle wood in a timely way through biological, thermal, aqueous, photochemical, chemical, and mechanical degradations. In simple terms, nature builds wood from carbon dioxide and water and has all the tools to recycle it back to the starting chemicals...

  1. Rapid shallow breathing

    Science.gov (United States)

    ... the smallest air passages of the lungs in children ( bronchiolitis ) Pneumonia or other lung infection Transient tachypnea of the newborn Anxiety and panic Other serious lung disease Home Care Rapid, shallow breathing should not be treated at home. It is ...

  2. Rapid Strep Test

    Science.gov (United States)

    ... worse than normal. Your first thoughts turn to strep throat. A rapid strep test in your doctor’s office ... your suspicions.Viruses cause most sore throats. However, strep throat is an infection caused by the Group A ...

  3. RAPID3? Aptly named!

    Science.gov (United States)

    Berthelot, J-M

    2014-01-01

    The RAPID3 score is the sum of three 0-10 patient self-report scores: pain, functional impairment on MDHAQ, and patient global estimate. It requires 5 seconds for scoring and can be used in all rheumatologic conditions, although it has mostly been used in rheumatoid arthritis where cutoffs for low disease activity (12/30) have been set. A RAPID3 score of ≤ 3/30 with 1 or 0 swollen joints (RAPID3 ≤ 3 + ≤ SJ1) provides remission criteria comparable to Boolean, SDAI, CDAI, and DAS28 remission criteria, in far less time than a formal joint count. RAPID3 performs as well as the DAS28 in separating active drugs from placebos in clinical trials. RAPID3 also predicts subsequent structural disease progression. RAPID3 can be determined at short intervals at home, allowing the determination of the area under the curve of disease activity between two visits and flare detection. However, RAPID3 should not be seen as a substitute for DAS28 and face to face visits in routine care. Monitoring patient status with only self-report information without a rheumatologist's advice (including joints and physical examination, and consideration of imaging and laboratory tests) may indeed be as undesirable for most patients than joint examination without a patient questionnaire. Conversely, combining the RAPID3 and the DAS28 may consist in faster or more sensitive confirmation that a medication is effective. Similarly, better enquiring of most important concerns of patients (pain, functional status and overall opinion on their disorder) should reinforces patients' confidence in their rheumatologist and treatments.

  4. Rapid self-healing hydrogels

    Science.gov (United States)

    Phadke, Ameya; Zhang, Chao; Arman, Bedri; Hsu, Cheng-Chih; Mashelkar, Raghunath A.; Lele, Ashish K.; Tauber, Michael J.; Arya, Gaurav; Varghese, Shyni

    2012-01-01

    Synthetic materials that are capable of autonomous healing upon damage are being developed at a rapid pace because of their many potential applications. Despite these advancements, achieving self-healing in permanently cross-linked hydrogels has remained elusive because of the presence of water and irreversible cross-links. Here, we demonstrate that permanently cross-linked hydrogels can be engineered to exhibit self-healing in an aqueous environment. We achieve this feature by arming the hydrogel network with flexible-pendant side chains carrying an optimal balance of hydrophilic and hydrophobic moieties that allows the side chains to mediate hydrogen bonds across the hydrogel interfaces with minimal steric hindrance and hydrophobic collapse. The self-healing reported here is rapid, occurring within seconds of the insertion of a crack into the hydrogel or juxtaposition of two separate hydrogel pieces. The healing is reversible and can be switched on and off via changes in pH, allowing external control over the healing process. Moreover, the hydrogels can sustain multiple cycles of healing and separation without compromising their mechanical properties and healing kinetics. Beyond revealing how secondary interactions could be harnessed to introduce new functions to chemically cross-linked polymeric systems, we also demonstrate various potential applications of such easy-to-synthesize, smart, self-healing hydrogels. PMID:22392977

  5. Model-order reduction of biochemical reaction networks

    NARCIS (Netherlands)

    Rao, Shodhan; Schaft, Arjan van der; Eunen, Karen van; Bakker, Barbara M.; Jayawardhana, Bayu

    2013-01-01

    In this paper we propose a model-order reduction method for chemical reaction networks governed by general enzyme kinetics, including the mass-action and Michaelis-Menten kinetics. The model-order reduction method is based on the Kron reduction of the weighted Laplacian matrix which describes the

  6. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. EKAMBARAM BALARAMAN. Articles written in Journal of Chemical Sciences. Volume 129 Issue 8 August 2017 pp 1153-1159 RAPID COMMUNICATION. Nickel-catalyzed direct synthesis of dialkoxymethane ethers · MURUGAN SUBARAMANIAN ABHIJIT BERA ...

  7. Reduction in language testing

    DEFF Research Database (Denmark)

    Dimova, Slobodanka; Jensen, Christian

    2013-01-01

    /video recorded speech samples and written reports produced by two experienced raters after testing. Our findings suggest that reduction or reduction-like pronunciation features are found in tested L2 speech, but whenever raters identify and comment on such reductions, they tend to assess reductions negatively...

  8. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  9. Girdling and Applying Chemicals Promote Rapid Rooting of Sycamore Cuttings

    Science.gov (United States)

    Robert C. Hare

    1975-01-01

    Shoots of 6- and 13-year-old sycamore (Platanus occidentalis L.) were girdled and treated with rooting powder 4 weeks before cuttings were taken. The powder, which contained auxins, sucrose, and cap tan, was also applied basally to nongirdled cuttings immediately before iwertion in a rooting medium. Thirteen days later, 100 percent of the...

  10. Rapid Neutron Capture Process in Supernovae and Chemical ...

    Indian Academy of Sciences (India)

    We have studied the r-process path corresponding to temperatures ranging from 1.0 × 109 K to 3.0 × 109 K and neutron density ranging from 1020 cm-3 to 1030 cm-3. With temperature and density conditions of 3.0 × 109 K and 1020 cm-3 a nucleus of mass 273 was theoretically found corresponding to atomic number 115.

  11. Rapid Neutron Capture Process in Supernovae and Chemical ...

    Indian Academy of Sciences (India)

    process in the supernova envelope at a high neutron density and a temperature of 109 degrees. ... Major advances have been made in calculating r-process .... Also electron capture on free protons is limited by the small abundance of free protons. These prob- lems are eased by higher density and higher temperature, ...

  12. Chemical Peel

    Science.gov (United States)

    ... complications in chemical peeling. Journal of Cutaneous and Aesthetic Surgery. 2010;3:186. Langsdon PR, et al. ... Discovery's Edge Magazine Search Publications Training Grant Positions Education Mayo Clinic College of Medicine and Science Mayo ...

  13. Chemical carcinogens

    National Research Council Canada - National Science Library

    Searle, Charles E

    1976-01-01

    Cancer causing agents are now known to exist throughout the environment-in polluted air and tobacco smoke, in various plants and foods, and in many chemicals that are used in industry and laboratories...

  14. Chemical Carcinogenesis

    OpenAIRE

    Oliveira, Paula A.; Aura Colaço; Raquel Chaves; Henrique Guedes-Pinto; Luis F. De-La-Cruz P.; Carlos Lopes

    1980-01-01

    The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process...

  15. Toxicokinetic triage for environmental chemicals

    NARCIS (Netherlands)

    Wambaugh, J.F.; Wetmore, B.A.; Pearce, R.; Strope, C.; Goldsmith, R.; Sluka, J.P.; Sedykh, A.; Tropsha, A.; Bosgra, S.; Shah, I.; Judson, R.; Thomas, R.S.; Setzer, R.W.

    2015-01-01

    Toxicokinetic (TK) models link administered doses to plasma, blood, and tissue concentrations. High-throughput TK (HTTK) performs in vitro to in vivo extrapolation to predict TK from rapid in vitro measurements and chemical structure-based properties. A significant toxicological application of HTTK

  16. Characterization of properties and reduction behavior of iron ores for application in sponge ironmaking

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M.; Jena, S.; Patel, S.K. [National Institute of Technology, Rourkela (India)

    2008-07-01

    Studies on the chemical and physical properties, and the reduction behavior (in coal) of hematite iron ores procured from 10 different mines of Orissa, were undertaken to provide information for the iron and steel industries (sponge iron plants in particular). The majority of the iron ores were found to have high iron and low alumina and silica contents. All these iron ores were free from the deleterious elements (S, P, As, Pb, alkalies, etc.). The results indicated lower values of shatter and abrasion indices, and higher values of tumbler index in all the iron ore lumps except Serazuddin (previous) and Khanda Bandha OMC Ltd. For all the fired iron ore pellets, the degree of reduction in coal was more intense in the first 30min, after which it became small. Slow heating led to higher degree of reduction in fired pellets than rapid heating. All the iron ores exhibited more than a 90% reduction in their fired pellets in 2-h time interval at a temperature of 900C. Iron ore lumps showed a lower degree of reduction than the corresponding fired pellets.

  17. Chemical carcinogenesis.

    Science.gov (United States)

    Oliveira, Paula A; Colaço, Aura; Chaves, Raquel; Guedes-Pinto, Henrique; De-La-Cruz P, Luis F; Lopes, Carlos

    2007-12-01

    The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process of chemical carcinogenesis. There are three stages involved in chemical carcinogenesis. These are defined as initiation, promotion and progression. Each of these stages is characterised by morphological and biochemical modifications and result from genetic and/or epigenetic alterations. These genetic modifications include: mutations in genes that control cell proliferation, cell death and DNA repair--i.e. mutations in proto-oncogenes and tumour suppressing genes. The epigenetic factors, also considered as being non-genetic in character, can also contribute to carcinogenesis via epigenetic mechanisms which silence gene expression. The control of responses to carcinogenesis through the application of several chemical, biochemical and biological techniques facilitates the identification of those basic mechanisms involved in neoplasic development. Experimental assays with laboratory animals, epidemiological studies and quick tests enable the identification of carcinogenic compounds, the dissection of many aspects of carcinogenesis, and the establishment of effective strategies to prevent the cancer which results from exposure to chemicals.

  18. Rapid small lot manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, R.W.

    1998-05-09

    The direct connection of information, captured in forms such as CAD databases, to the factory floor is enabling a revolution in manufacturing. Rapid response to very dynamic market conditions is becoming the norm rather than the exception. In order to provide economical rapid fabrication of small numbers of variable products, one must design with manufacturing constraints in mind. In addition, flexible manufacturing systems must be programmed automatically to reduce the time for product change over in the factory and eliminate human errors. Sensor based machine control is needed to adapt idealized, model based machine programs to uncontrolled variables such as the condition of raw materials and fabrication tolerances.

  19. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  20. Rapid Cycling and Its Treatment

    Science.gov (United States)

    ... Announcements Public Service Announcements Partnering with DBSA Rapid Cycling and its Treatment What is bipolar disorder? Bipolar ... to Depression and Manic Depression . What is rapid cycling? Rapid cycling is defined as four or more ...

  1. Compilation of an emissions data base for Europe, base year 1995, and development of large scale emissions reduction scenarios for the chemical transport model REM/CALGRID. Final report; Modellierung und Puefung von Strategien zur Verminderung der Belastung durch Ozon. Erstellung einer europaweiten Emissionsdatenbasis mit Bezugsjahr 1995 und die Erarbeitung von Emissionsszenarien fuer die grossraeumigen Ausbreitungsrechnungen mit REM/CALGRID. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stern, R.

    2003-02-01

    The report describes the emissions data base created by TNO, Netherlands, which is used for the chemical transport model REM/CALGRID. Base year is 1995. The data base covers Europe with grids of 0.5 x 0.25 lat long and contains the anthropogenic emissions of SO{sub 2}, NO{sub x}, NMVOC, CO, CH{sub 4}, NH{sub 3}, PM{sub 10}, PM{sub 2.5}. The data base uses CORINAIR and CEPMEIP information and the SNAP source group classifiction of CORINAIR. For emissions scenario calculations, 3 scenarios were developed based on information provided by IIASA: situation 2005, CLE-scenario 2010 and MFR-scenario 2010. The CLE-scenario is based on the current legislation and the national emissions ceilings, NEC. The MFR-scenario describes the maximum feasible reduction measures. (orig.)

  2. Matriptase autoactivation is tightly regulated by the cellular chemical environments.

    Directory of Open Access Journals (Sweden)

    Jehng-Kang Wang

    Full Text Available The ability of cells to rapidly detect and react to alterations in their chemical environment, such as pH, ionic strength and redox potential, is essential for cell function and survival. We present here evidence that cells can respond to such environmental alterations by rapid induction of matriptase autoactivation. Specifically, we show that matriptase autoactivation can occur spontaneously at physiological pH, and is significantly enhanced by acidic pH, both in a cell-free system and in living cells. The acid-accelerated autoactivation can be attenuated by chloride, a property that may be part of a safety mechanism to prevent unregulated matriptase autoactivation. Additionally, the thio-redox balance of the environment also modulates matriptase autoactivation. Using the cell-free system, we show that matriptase autoactivation is suppressed by cytosolic reductive factors, with this cytosolic suppression being reverted by the addition of oxidizing agents. In living cells, we observed rapid induction of matriptase autoactivation upon exposure to toxic metal ions known to induce oxidative stress, including CoCl2 and CdCl2. The metal-induced matriptase autoactivation is suppressed by N-acetylcysteine, supporting the putative role of altered cellular redox state in metal induced matriptase autoactivation. Furthermore, matriptase knockdown rendered cells more susceptible to CdCl2-induced cell death compared to control cells. This observation implies that the metal-induced matriptase autoactivation confers cells with the ability to survive exposure to toxic metals and/or oxidative stress. Our results suggest that matriptase can act as a cellular sensor of the chemical environment of the cell that allows the cell to respond to and protect itself from changes in the chemical milieu.

  3. Redução do amaciamento de banana 'Maçã' minimamente processada pelo uso de tratamentos químicos Softening reduction of fresh-cut 'apple' banana by using of chemical treatments

    Directory of Open Access Journals (Sweden)

    Anderson Adriano Martins Melo

    2007-06-01

    (AA, calcium chloride (CC, L-cysteine hydrochloride (Cis and Na2EDTA, employed in association with modified atmosphere, on prevention of the softening of minimally processed 'Apple' banana. The following combinations were used: 1 (AA 1% + CC 1% + Cis 0,5%; 2 (AA 1% + CC 1% + Cis 1%; 3 (AA 1% + CC 1% + Cis 1,5%; 4 (Na2EDTA 1%; forming the 4 treatments of a completely randomly design. The bananas, in maturity stage 6, were treated with a sodium hypochlorite solution 500 ppm, peeled and manually sliced, submitted to the chemical treatments by dipping and wrapped with PVC 30µm films. Later, the slices were stored during 5 days at 5 ± 1ºC e 85 ± 3% UR. The mass loss was linear during the storage period and higher in Na2EDTA 1% treated slices. The firmness loss was lesser in the slices under the treatment 3, which presented lower polygalacturonase activity values until the 3rd day of storage. After the second day of storage, the slices under the treatment 4 showed the highest pectinmethylesterase activity, and those under treatments 2 and 3, the lowest. Higher content of soluble pectin and total soluble solids were observed in EDTA treated slices, mainly beginning from the 3rd day of storage. The increase in total soluble sugars was higher in the treatments 1 and 2 until the 3rd day of storage. The chemical mixture 3 (AA 1% + CC 1% + Cis 1,5% was the most effective in avoiding the softening of minimally processed 'Apple' bananas.

  4. Gene regulation and noise reduction by coupling of stochastic processes.

    Science.gov (United States)

    Ramos, Alexandre F; Hornos, José Eduardo M; Reinitz, John

    2015-02-01

    Here we characterize the low-noise regime of a stochastic model for a negative self-regulating binary gene. The model has two stochastic variables, the protein number and the state of the gene. Each state of the gene behaves as a protein source governed by a Poisson process. The coupling between the two gene states depends on protein number. This fact has a very important implication: There exist protein production regimes characterized by sub-Poissonian noise because of negative covariance between the two stochastic variables of the model. Hence the protein numbers obey a probability distribution that has a peak that is sharper than those of the two coupled Poisson processes that are combined to produce it. Biochemically, the noise reduction in protein number occurs when the switching of the genetic state is more rapid than protein synthesis or degradation. We consider the chemical reaction rates necessary for Poisson and sub-Poisson processes in prokaryotes and eucaryotes. Our results suggest that the coupling of multiple stochastic processes in a negative covariance regime might be a widespread mechanism for noise reduction.

  5. Microstructure and mechanical properties of rapidly solidified FeAlCr intermetallic compound

    Directory of Open Access Journals (Sweden)

    R. A. Rodríguez‐Díaz

    2009-08-01

    Full Text Available In this work results regarding microstructural characterization of a melt‐spun intermetallic compound Fe40Al5Cr (% at.produced by rapid solidification employing the melt spinning technique at three different tangential wheel speeds (12, 16 and20 ms‐1 are presented. Melt spun ribbons were characterized by optical and scanning electron microscopy (SEM in order toobserve morphology, grain size, ribbon thickness and also fracture surfaces after tensile tests. EDS coupled to SEM wasemployed to perform punctual and scan line chemical analyses on samples, x‐ray diffraction (XRD was utilized to identify crystalstructure and phases. Transmission electron microscopy (TEM was employed to confirm crystal structure and also tocharacterize nanopores formed in the specimens by vacancy clustering. With regard to mechanical properties, micro hardnessVickers measurements as well as tensile tests at room temperature were applied to the rapidly solidified ribbons.The grain size of rapidly solidified Fe40Al5Cr ribbons suffered a drastic reduction as compared with alloys of the samecomposition produced by conventional melting and casting methods, and in melt‐spun ribbons it decreases as the wheel speedincreases. Punctual and line‐scanning chemical analyses revealed that Cr enters in solid solution in FeAl matrix. Hardnessmeasurements revealed a softening in rapidly solidified FeAlCr ribbons as compared with FeAl alloys and tensile test exhibited a(transgranular + intergranular mode of fracture, reaching up to 3 % of elongation in FeAlCr alloys. The presence of porous(meso and nano were also characterized.

  6. Rapid manufacturing for microfluidics

    CSIR Research Space (South Africa)

    Land, K

    2012-10-01

    Full Text Available . Microfluidics is at the forefront of developing solutions for drug discovery, diagnostics (from glucose tests to malaria and TB testing) and environmental diagnostics (E-coli monitoring of drinking water). In order to quickly implement new designs, a rapid...

  7. Rapid Prototyping in PVS

    Science.gov (United States)

    Munoz, Cesar A.; Butler, Ricky (Technical Monitor)

    2003-01-01

    PVSio is a conservative extension to the PVS prelude library that provides basic input/output capabilities to the PVS ground evaluator. It supports rapid prototyping in PVS by enhancing the specification language with built-in constructs for string manipulation, floating point arithmetic, and input/output operations.

  8. Rapid Prototyping Reconsidered

    Science.gov (United States)

    Desrosier, James

    2011-01-01

    Continuing educators need additional strategies for developing new programming that can both reduce the time to market and lower the cost of development. Rapid prototyping, a time-compression technique adapted from the high technology industry, represents one such strategy that merits renewed evaluation. Although in higher education rapid…

  9. Rapid Column Extraction method for SoilRapid Column Extraction method for Soil

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod, L. III; Culligan, Brian K.

    2005-11-07

    The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu) neptunium (Np), uranium (U), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha spectrometry. The method combines a rapid fusion step for total dissolution to dissolve refractory analytes and matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

  10. Combined coal gasification and Fe{sub 3}O{sub 4}-reduction using high-temperature solar process heat

    Energy Technology Data Exchange (ETDEWEB)

    Tamaura, Y. [Tokyo Inst. of Technology, Tokyo (Japan); Ehrensberger, K.; Steinfeld, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The coal/Fe{sub 3}O{sub 4} system was experimentally studied at PSI solar furnace. The reactants were directly exposed to a solar flux irradiation of 3,000 suns (1 sun = 1 kW/m{sup 2}). The combined gasification of coal and reduction of Fe{sub 2}O{sub 3} proceeded rapidly after only one second exposure, suggesting an efficient heat transfer and chemical conversion by direct solar energy absorption at the reaction site. The proposed solar thermochemical process offers the possibility of converting coal to a cleaner fluid fuel with a solar-upgraded calorific value. (author) 2 figs., 8 refs.

  11. 77 FR 69484 - Agency Forms Undergoing Paperwork Reduction Act Review

    Science.gov (United States)

    2012-11-19

    ... HUMAN SERVICES Centers for Disease Control and Prevention Agency Forms Undergoing Paperwork Reduction...--Scientific Education and Professional Development Program Office (SEPDPO), Office of Surveillance... public health problems rapidly ensures cost-effective health care and enhances health promotion and...

  12. Collaborating for Multi-Scale Chemical Science

    Energy Technology Data Exchange (ETDEWEB)

    William H. Green

    2006-07-14

    Advanced model reduction methods were developed and integrated into the CMCS multiscale chemical science simulation software. The new technologies were used to simulate HCCI engines and burner flames with exceptional fidelity.

  13. Cutaneous chemical burns: assessment and early management.

    Science.gov (United States)

    Gnaneswaran, Neiraja; Perera, Eshini; Perera, Marlon; Sawhney, Raja

    2015-03-01

    Chemical burns are common and may cause significant physical, psychological, social and economic burden. Despite a wide variety of potentially harmful chemicals, important general principals may be drawn in the assessment and initial management of such injuries. Early treatment of chemical burns is crucial and may reduce the period of resulting morbidity. This article reviews the assessment and management of cutaneous chemical burns. Assessment of the patient should be rapid and occur in conjunction with early emergency management. Rapid history and pri-mary and secondary survey may be required to exclude systemic side effects of the injury. Depth of wound assessment is difficult given that necrosis caused by various chemicals can continue despite cessation of exposure. Early management should be conducted with consideration of clinician's safety, and appropriate precautions should be taken. Excluding specific situations and chemical exposure, copious irrigation with water remains the mainstay of early management. Referral to a centre of higher acuity may be required for expert evaluation.

  14. Modern Reduction Methods

    CERN Document Server

    Andersson, Pher G

    2008-01-01

    With its comprehensive overview of modern reduction methods, this book features high quality contributions allowing readers to find reliable solutions quickly and easily. The monograph treats the reduction of carbonyles, alkenes, imines and alkynes, as well as reductive aminations and cross and heck couplings, before finishing off with sections on kinetic resolutions and hydrogenolysis. An indispensable lab companion for every chemist.

  15. China urges rapid growth

    Energy Technology Data Exchange (ETDEWEB)

    Hendry, S.

    1993-02-03

    This time last year China's paramount leader, Deng Xiaoping, launched the country on another bout of fast-paced economic growth and restructuring. After three years of riding out political and economic clampdown, foreign chemical companies were jerked awake by major changes in China's chemical industry. As the state becomes less involved with managing the economy, unleashing 12% gross national product growth, closer involvement with domestic factories has become attractive and essential. MCI officials say government funds will now be channeled toward clearing energy and transport bottlenecks, and chemical enterprises will be given more chance to turn a profit. They will be allowed to issue shares, seek foreign investment partners themselves, and bypass trading companies like China National Import-Export Corp. (Sinochem), the former state monopoly. Foreign analysts question whether China's finances and oil resources can support expansion. Even if they can, Cai estimates that ethylene imports will remain around the present level of 1 million tons. To further guarantee chemical supplies, China has invested in urea and polypropylene plants in the US and polystyrene plant in Hong Kong.

  16. SUPPLEMENTARY INFORMATION RAPID COMMUNICATION ...

    Indian Academy of Sciences (India)

    Sulfated polyborate: A mild, efficient catalyst for synthesis of N-tert- butyl/N-trityl protected amides via Ritter reaction. KRISHNA S INDALKAR, CHETAN K KHATRI and GANESH U CHATURBHUJ*. Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, Mumbai, Maharashtra 400 019 ...

  17. Delicious Chemicals.

    Science.gov (United States)

    Barry, Dana M.

    This paper presents an approach to chemistry and nutrition that focuses on food items that people consider delicious. Information is organized according to three categories of food chemicals that provide energy to the human body: (1) fats and oils; (2) carbohydrates; and (3) proteins. Minerals, vitamins, and additives are also discussed along with…

  18. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil

  19. Chemical Oscillations

    Indian Academy of Sciences (India)

    processes at the cellular level like the glycolytic pathway, peroxi- dase-catalysed reaction or the biosynthesis of certain proteins. A systematic study of oscillating chemical reactions is of consider- able interest, since these oscillating reactions can be used as prototype examples of the behaviours possible in reactions gov-.

  20. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. KRISHNA S INDALKAR. Articles written in Journal of Chemical Sciences. Volume 129 Issue 2 February 2017 pp 141-148 Rapid Communication. Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated ...

  1. Rapid manufacturing facilitated customisation

    OpenAIRE

    Tuck, Christopher John; Hague, Richard; Ruffo, Massimiliano; Ransley, Michelle; Adams, Paul Russell

    2008-01-01

    Abstract This paper describes the production of body-fitting customised seat profiles utilising the following digital methods: three dimensional laser scanning, reverse engineering and Rapid Manufacturing (RM). The seat profiles have been manufactured in order to influence the comfort characteristics of an existing ejector seat manufactured by Martin Baker Aircraft Ltd. The seat, known as Navy Aircrew Common Ejection Seat (NACES), was originally designed with a generic profile. ...

  2. Rapid Detection of Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    David Perlin

    2005-08-14

    Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development

  3. Tiber Personal Rapid Transit

    Directory of Open Access Journals (Sweden)

    Diego Carlo D'agostino

    2011-02-01

    Full Text Available The project “Tiber Personal Rapid Transit” have been presented by the author at the Rome City Vision Competition1 2010, an ideas competition, which challenges architects, engineers, designers, students and creatives individuals to develop visionary urban proposals with the intention of stimulating and supporting the contemporary city, in this case Rome. The Tiber PRT proposal tries to answer the competition questions with the definition of a provocative idea: a Personal Rapid transit System on the Tiber river banks. The project is located in the central section of the Tiber river and aims at the renewal of the river banks with the insertion of a Personal Rapid Transit infrastructure. The project area include the riverbank of Tiber from Rome Transtevere RFI station to Piazza del Popolo, an area where main touristic and leisure attractions are located. The intervention area is actually no used by the city users and residents and constitute itself a strong barrier in the heart of the historic city.

  4. Initiation of the Electrochemical Reduction of CO2 by a Singly Reduced Ruthenium(II) Bipyridine Complex.

    Science.gov (United States)

    Ramakrishnan, Srinivasan; Chidsey, Christopher E D

    2017-07-17

    The one-electron reduction of [CpRu(bpy)NCCH3]PF6 (Cp = cyclopentadienyl; bpy = 2,2'-bipyridine), abbreviated as [Ru-S]+, where S = CH3CN, in CO2-saturated acetonitrile initiates a cascade of rapid electrochemical and chemical steps (ECEC) at an electrode potential of ca. 100 mV positive of the first reduction of the ruthenium complex. The overall two-electron process leads to the generation of a CO-bound ruthenium complex, [Ru-CO]+, and carbonate, as independently confirmed by NMR spectroscopy. Simulations of the cyclic voltammograms using DigiElch together with density functional theory based calculations reveal that the singly reduced ruthenium complex [Ru-S]0 binds CO2 at a rate of ca. 105 M-1 s-1 at almost zero driving force. Subsequent to CO2 binding, all of the steps leading up to deoxygenation are highly exergonic and rapid. A model of the potential energy profile of the CO2 approach to the Ru center in the singly reduced manifold reveals a direct correlation between the reactivity toward CO2 and the nucleophilicity at the metal center influenced by different ligand environments. Through the binding of CO2 after the first reduction, overpotentials associated with consecutive electrochemical reductions are avoided. This work therefore provides an important design principle for engineering transition-metal complexes to activate CO2 under low driving forces.

  5. Chemical routes to discharging graphenides.

    Science.gov (United States)

    Hodge, Stephen A; Buckley, David J; Yau, Hin Chun; Skipper, Neal T; Howard, Christopher A; Shaffer, Milo S P

    2017-03-02

    Chemical and electrochemical reduction methods allow the dispersion, processing, and/or functionalization of discrete sp(2)-hybridised nanocarbons, including fullerenes, nanotubes and graphenes. Electron transfer to the nanocarbon raises the Fermi energy, creating nanocarbon anions and thereby activating an array of possible covalent reactions. The Fermi level may then be partially or fully lowered by intended functionalization reactions, but in general, techniques are required to remove excess charge without inadvertent covalent reactions that potentially degrade the nanocarbon properties of interest. Here, simple and effective chemical discharging routes are demonstrated for graphenide polyelectrolytes and are expected to apply to other systems, particularly nanotubides. The discharging process is inherently linked to the reduction potentials of such chemical discharging agents and the unusual fundamental chemistry of charged nanocarbons.

  6. A Review on Aflatoxins Reduction in Food

    Directory of Open Access Journals (Sweden)

    Maryam Jalili

    2016-01-01

    Full Text Available Aflatoxins (AFs are cancerous secondary metabolites produced primarily by Aspergillus flavus and Aspergillus parasiticus in agricultural foodstuff such as peanuts, maize grains, cereals, and animal feeds. Food and Agricultural organization (FAO estimated that as much as 25% of the world’s agricultural commodities are contaminated with mycotoxins, leading to significant economic losses. Moreover, AFs are highly toxic, mutagenic, teratogenic and carcinogenic. Therefore AFs reduction in food and feedstuffs is a major global concern. This review aims to bring up to date the detoxification methods applied for reduction of aflatoxins by physical (cleaning, heating, irradiation, adsorption, chemical (chemical compound, ozonization and biological (applying bacteria, yeast and nontoxigenic Aspergillus strains methods in different foods from 2000 to 2015. Papers related to aflatoxin reduction by managing aflatoxins risks, using resistant crops varieties, and good agricultural practices and papers related to other aflatoxins (M1, M2 were excluded.

  7. Rapid Biosynthesis of Silver Nanoparticles Using Culture Supernatant of Bacteria with Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    N. Saifuddin

    2009-01-01

    Full Text Available The development of rapid and reliable processes for the synthesis of nanosized materials is of great importance in the field of nanotechnology. Synthesis of silver nanoparticles using microorganism have been reported, but the process is rather slow. In this paper, we describe a novel combinatorial synthesis approach which is rapid, simple and “green” for the synthesis of metallic nanostructures of noble metals such as silver (Ag, by using a combination of culture supernatanant of Bacillus subtilis and microwave (MW irradiation in water in absence of a surfactant or soft template. It was found that exposure of culture supernatanant of Bacillus subtilis and microwave irradiation to silver ion lead to the formation of silver nanoparticles. The silver nanoparticles were in the range of 5-60 nm in dimension. The nanoparticles were examined using UV-Visible Spectroscopy, and Transmission Electron Microscopy (TEM analyses. The formation of nanoparticles by this method is extremely rapid, requires no toxic chemicals and the nanoparticles are stable for several months. The main conclusion is that the bio-reduction method to produce nanoparticles is a good alternative to the electrochemical methods.

  8. Reduction of residual limb volume in people with transtibial amputation

    NARCIS (Netherlands)

    Tantua, Audrey T.; Geertzen, Jan H. B.; van den Dungen, Jan J. A. M.; Breek, Jan-Kees C.; Dijkstra, Pieter U.

    2014-01-01

    The early postoperative phase after transtibial amputation is characterized by rapid residual limb volume reduction. Accurate measurement of residual limb volume is important for the timing of fitting a prosthesis. The aim of this study was to analyze the reduction of residual limb volume in people

  9. Lethal and pre-lethal effects of a fungal biopesticide contribute to substantial and rapid control of malaria vectors.

    Directory of Open Access Journals (Sweden)

    Simon Blanford

    Full Text Available Rapidly emerging insecticide resistance is creating an urgent need for new active ingredients to control the adult mosquitoes that vector malaria. Biopesticides based on the spores of entomopathogenic fungi have shown considerable promise by causing very substantial mortality within 7-14 days of exposure. This mortality will generate excellent malaria control if there is a high likelihood that mosquitoes contact fungi early in their adult lives. However, where contact rates are lower, as might result from poor pesticide coverage, some mosquitoes will contact fungi one or more feeding cycles after they acquire malaria, and so risk transmitting malaria before the fungus kills them. Critics have argued that 'slow acting' fungal biopesticides are, therefore, incapable of delivering malaria control in real-world contexts. Here, utilizing standard WHO laboratory protocols, we demonstrate effective action of a biopesticide much faster than previously reported. Specifically, we show that transient exposure to clay tiles sprayed with a candidate biopesticide comprising spores of a natural isolate of Beauveria bassiana, could reduce malaria transmission potential to zero within a feeding cycle. The effect resulted from a combination of high mortality and rapid fungal-induced reduction in feeding and flight capacity. Additionally, multiple insecticide-resistant lines from three key African malaria vector species were completely susceptible to fungus. Thus, fungal biopesticides can block transmission on a par with chemical insecticides, and can achieve this where chemical insecticides have little impact. These results support broadening the current vector control paradigm beyond fast-acting chemical toxins.

  10. Effect of thiols enrichment on Cr(VI) photo-reduction by natural organic matter (NOM).

    Science.gov (United States)

    Luo, Hong-Wei

    2016-05-01

    Photochemical redox transformation of Cr(VI)-NOM complexes substantially affects transport and speciation of less toxic Cr(III) in natural waters. However, the underlying mechanisms remain unclear. This study reported photochemical reactions of Cr(VI) with thiol-enriched NOM under acidic condition. More effective thiols enrichment in humic acid (HA) was observed than that in fulvic acid (FA), thereby resulting in a higher reduction capacity and faster rate of Cr(VI) photo-reduction. Chemical addition of sulfide to HA formed a large number of S-containing molecular formulae, which subsequently disappeared following reactions with Cr(VI) under solar irradiation. Cr(VI) photo-reduction in thiol-enriched HA consumed more S-containing formulae. Solar irradiation caused a rapid loss of the reduction capacities and thiol contents in HA and FA. All these findings can provide useful information for understanding the biogeochemical cycles of chromium and sulfur, and are also of environmental significance because they may partially account for photo-transformation of Cr(VI) when chromium enters into the aquatic environment as acidic industrial effluents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  12. Rapid prototype and test

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, D.L.; Hansche, B.D.

    1996-06-01

    In order to support advanced manufacturing, Sandia has acquired the capability to produce plastic prototypes using stereolithography. Currently, these prototypes are used mainly to verify part geometry and ``fit and form`` checks. This project investigates methods for rapidly testing these plastic prototypes, and inferring from prototype test data actual metal part performance and behavior. Performances examined include static load/stress response, and structural dynamic (modal) and vibration behavior. The integration of advanced non-contacting measurement techniques including scanning laser velocimetry, laser holography, and thermoelasticity into testing of these prototypes is described. Photoelastic properties of the epoxy prototypes to reveal full field stress/strain fields are also explored.

  13. Right-Rapid-Rough

    Science.gov (United States)

    Lawrence, Craig

    2003-01-01

    IDEO (pronounced 'eye-dee-oh') is an international design, engineering, and innovation firm that has developed thousands of products and services for clients across a wide range of industries. Its process and culture attracted the attention of academics, businesses, and journalists around the world, and are the subject of a bestselling book, The Art of Innovation by Tom Kelley. One of the keys to IDEO's success is its use of prototyping as a tool for rapid innovation. This story covers some of IDEO's projects, and gives reasons for why they were successful.

  14. On model reduction

    Science.gov (United States)

    Al-Saggaf, Ubaid M.; Franklin, Gene F.

    1986-01-01

    Three model reduction methods are described. These are the discrete balanced realizations of Mullis and Roberts (1976) where a characterization of the reduction error is given and a previously unknown L(infinity) norm bound on the reduction error, is obtained. Another method is a new model reduction technique for discrete time systems which has the advantage that the reduced order model is balanced and has an L(infinity) norm bound on the reduction error. The last method derived is a frequency weighting technique for continuous and discrete systems where it is possible to specify the approximation accuracy with frequency and also, for this method, an L(infinity) norm on the weighted reduction error is obtained.

  15. Quantum State Reduction

    OpenAIRE

    Brody, DC; Hughston, LP

    2016-01-01

    We propose an energy-driven stochastic master equation for the density matrix as a dynamical model for quantum state reduction. In contrast, most previous studies of state reduction have considered stochastic extensions of the Schr¨odinger equation, and have introduced the density matrix as the expectation of the random pure projection operator associated with the evolving state vector. After working out properties of the reduction process we construct a general solution to the energy- driven...

  16. Rapid mineralocorticoid receptor trafficking.

    Science.gov (United States)

    Gekle, M; Bretschneider, M; Meinel, S; Ruhs, S; Grossmann, C

    2014-03-01

    The mineralocorticoid receptor (MR) is a ligand-dependent transcription factor that physiologically regulates water-electrolyte homeostasis and controls blood pressure. The MR can also elicit inflammatory and remodeling processes in the cardiovascular system and the kidneys, which require the presence of additional pathological factors like for example nitrosative stress. However, the underlying molecular mechanism(s) for pathophysiological MR effects remain(s) elusive. The inactive MR is located in the cytosol associated with chaperone molecules including HSP90. After ligand binding, the MR monomer rapidly translocates into the nucleus while still being associated to HSP90 and after dissociation from HSP90 binds to hormone-response-elements called glucocorticoid response elements (GREs) as a dimer. There are indications that rapid MR trafficking is modulated in the presence of high salt, oxidative or nitrosative stress, hypothetically by induction or posttranslational modifications. Additionally, glucocorticoids and the enzyme 11beta hydroxysteroid dehydrogenase may also influence MR activation. Because MR trafficking and its modulation by micro-milieu factors influence MR cellular localization, it is not only relevant for genomic but also for nongenomic MR effects. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Rapid response manufacturing (RRM)

    Energy Technology Data Exchange (ETDEWEB)

    Cain, W.D. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Waddell, W.L. [National Centers for Manufacturing Sciences, Ann Arbor, MI (United States)

    1997-02-18

    US industry is fighting to maintain its competitive edge in the global market place. Today markets fluctuate rapidly. Companies, to survive, have to be able to respond with quick-to-market, improved, high quality, cost efficient products. The way products are developed and brought to market can be improved and made more efficient through the proper incorporation of emerging technologies. The RRM project was established to leverage the expertise and resources of US private industries and federal agencies to develop, integrate, and deploy new technologies that meet critical needs for effective product realization. The RRM program addressed a needed change in the US Manufacturing infrastructure that will ensure US competitiveness in world market typified by mass customization. This project provided the effort needed to define, develop and establish a customizable infrastructure for rapid response product development design and manufacturing. A major project achievement was the development of a broad-based framework for automating and integrating the product and process design and manufacturing activities involved with machined parts. This was accomplished by coordinating and extending the application of feature-based product modeling, knowledge-based systems, integrated data management, and direct manufacturing technologies in a cooperative integrated computing environment. Key technological advancements include a product model that integrates product and process data in a consistent, minimally redundant manner, an advanced computer-aided engineering environment, knowledge-based software aids for design and process planning, and new production technologies to make products directly from design application software.

  18. Drag reduction in nature

    Science.gov (United States)

    Bushnell, D. M.; Moore, K. J.

    1991-01-01

    Recent studies on the drag-reducing shapes, structures, and behaviors of swimming and flying animals are reviewed, with an emphasis on potential analogs in vehicle design. Consideration is given to form drag reduction (turbulent flow, vortex generation, mass transfer, and adaptations for body-intersection regions), skin-friction drag reduction (polymers, surfactants, and bubbles as surface 'additives'), reduction of the drag due to lift, drag-reduction studies on porpoises, and drag-reducing animal behavior (e.g., leaping out of the water by porpoises). The need for further research is stressed.

  19. Finding optimal exact reducts

    KAUST Repository

    AbouEisha, Hassan M.

    2014-01-01

    The problem of attribute reduction is an important problem related to feature selection and knowledge discovery. The problem of finding reducts with minimum cardinality is NP-hard. This paper suggests a new algorithm for finding exact reducts with minimum cardinality. This algorithm transforms the initial table to a decision table of a special kind, apply a set of simplification steps to this table, and use a dynamic programming algorithm to finish the construction of an optimal reduct. I present results of computer experiments for a collection of decision tables from UCIML Repository. For many of the experimented tables, the simplification steps solved the problem.

  20. Review of Cement Concrete Pavement of Noise Reduction Method

    Directory of Open Access Journals (Sweden)

    Tao Hongliang

    2017-01-01

    Full Text Available In recent years, with the rapid development of the economy, a sharp increase in car ownership in China, the rapid increase in cities traffic volume. Meanwhile, the effect on the normal life, work, study, rest and environment of residents along grows increasingly fierce both in extent and scope. Cement Concrete Pavement noise reduction measures seem more urgent. In this paper, introducing the current commonly used cement pavement noise reduction measures, and discussing the research and development direction of cement concrete pavement noise reduction measures.

  1. Ultralow Level Mercury Treatment Using Chemical Reduction and Air Stripping

    Energy Technology Data Exchange (ETDEWEB)

    Looney, B.B.

    2001-02-23

    The overall objective of this work is to develop a reasonable and cost-effective approach to meet the emerging mercury standards, especially for high volume outfalls with concentrations below the drinking water standard.

  2. Chemical munitions dumped at sea

    Science.gov (United States)

    Edwards, Margo; Bełdowski, Jacek

    2016-06-01

    Modern chemical warfare is a byproduct of the industrial revolution, which created factories capable of rapidly producing artillery shells that could be filled with toxic chemicals such as chlorine, phosgene and mustard agent. The trench warfare of World War I inaugurated extensive deployments of modern chemical weapons in 1915. Concomitantly, the need arose to dispose of damaged, captured or excess chemical munitions and their constituents. Whereas today chemical warfare agents (CWA) are destroyed via chemical neutralization processes or high-temperature incineration in tandem with environmental monitoring, in the early to middle 20th century the options for CWA disposal were limited to open-air burning, burial and disposal at sea. The latter option was identified as the least likely of the three to impact mankind, and sea dumping of chemical munitions commenced. Eventually, the potential impacts of sea dumping human waste were recognized, and in 1972 an international treaty, the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, was developed to protect the marine environment from pollution caused by the dumping of wastes and other matter into the ocean. By the time this treaty, referred to as the London Convention, was signed by a majority of nations, millions of tons of munitions were known to have been disposed throughout the world's oceans.

  3. Chemical carcinogenesis

    Directory of Open Access Journals (Sweden)

    Paula A. Oliveira

    2007-12-01

    Full Text Available The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process of chemical carcinogenesis. There are three stages involved in chemical carcinogenesis. These are defined as initiation, promotion and progression. Each of these stages is characterised by morphological and biochemical modifications and result from genetic and/or epigenetic alterations. These genetic modifications include: mutations in genes that control cell proliferation, cell death and DNA repair - i.e. mutations in proto-oncogenes and tumour suppressing genes. The epigenetic factors, also considered as being non-genetic in character, can also contribute to carcinogenesis via epigenetic mechanisms which silence gene expression. The control of responses to carcinogenesis through the application of several chemical, biochemical and biological techniques facilitates the identification of those basic mechanisms involved in neoplasic development. Experimental assays with laboratory animals, epidemiological studies and quick tests enable the identification of carcinogenic compounds, the dissection of many aspects of carcinogenesis, and the establishment of effective strategies to prevent the cancer which results from exposure to chemicals.A sociedade obtém numerosos benefícios da utilização de compostos químicos. A aplicação dos pesticidas, por exemplo, permitiu obter alimento em quantidade suficiente para satisfazer as necessidades alimentares de milhões de pessoas, condição relacionada com o aumento da esperança de vida. Os benefícios estão, por

  4. Chemical cosmology

    CERN Document Server

    Boeyens, Jan CA

    2010-01-01

    The composition of the most remote objects brought into view by the Hubble telescope can no longer be reconciled with the nucleogenesis of standard cosmology and the alternative explanation, in terms of the LAMBDA-Cold-Dark-Matter model, has no recognizable chemical basis. A more rational scheme, based on the chemistry and periodicity of atomic matter, opens up an exciting new interpretation of the cosmos in terms of projective geometry and general relativity. The response of atomic structure to environmental pressure predicts non-Doppler cosmical redshifts and equilibrium nucleogenesis by alp

  5. Enabling rapid behavioral ecotoxicity studies using an integrated lab-on-a-chip systems

    Science.gov (United States)

    Huang, Yushi; Nugegoda, Dayanthi; Wlodkowic, Donald

    2015-12-01

    Behavioral ecotoxicity tests are gaining an increasing recognition in environmental toxicology. Behavior of sensitive bioindicator species can change rapidly in response to an acute exposure to contaminants and thus has a much higher sensitivity as compared to conventional LC50 mortality tests. Furthermore, behavioral endpoints seems to be very good candidates to develop early-warning biomonitoring systems needed for rapid chemical risk assessment. Behavioral tests are non-invasive, fast, do not harm indicator organisms (behavioural changes are very rapid) and are thus fully compatible with 3R (Replacement - Reduction - Refinement) principle encouraging alternatives to conventional animal testing. These characteristics are essential when designing improved ecotoxicity tests for chemical risk assessment. In this work, we present a pilot development of miniaturized Lab-on-a-Chip (LOC) devices for studying toxin avoidance behaviors of small aquatic crustaceans. As an investigative tool, LOCs represent a new direction that may miniaturize and revolutionize behavioral ecotoxicology. Specifically our innovative microfluidic prototype: (i) enables convening "caging" of specimens for real-time videomicroscopy; (ii) eliminates the evaporative water loss thus providing an opportunity for long-term behavioral studies; (iii) exploits laminar fluid flow under low Reynolds numbers to generate discrete domains and gradients enabling for the first time toxin avoidance studies on small aquatic crustaceans; (iv) integrates off-the-chip mechatronic interfaces and video analysis algorithms for single animal movement analysis. We provide evidence that by merging innovative bioelectronic and biomicrofluidic technologies we can deploy inexpensive and reliable systems for culture, electronic tracking and complex computational analysis of behavior of bioindicator organisms.

  6. Rapid Refresh (RAP) [13 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  7. Rapid Refresh (RAP) [20 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  8. Strategies for poverty reduction

    OpenAIRE

    Øyen, Else

    2003-01-01

    SIU konferanse Solstrand 6.-7. October 2003 Higher education has a value of its own. When linked to the issue of poverty reduction it is necessary to ask another set of questions, including the crutial one whether higher education in general is the best tool for poverty reduction.

  9. Intelligent Data Reduction (IDARE)

    Science.gov (United States)

    Brady, D. Michael; Ford, Donnie R.

    1990-01-01

    A description of the Intelligent Data Reduction (IDARE) expert system and an IDARE user's manual are given. IDARE is a data reduction system with the addition of a user profile infrastructure. The system was tested on a nickel-cadmium battery testbed. Information is given on installing, loading, maintaining the IDARE system.

  10. Dirac reduction revisited

    OpenAIRE

    Marciniak, Krzysztof; Blaszak, Maciej

    2003-01-01

    The procedure of Dirac reduction of Poisson operators on submanifolds is discussed within a particularly useful special realization of the general Marsden-Ratiu reduction procedure. The Dirac classification of constraints on 'first-class' constraints and 'second-class' constraints is reexamined.

  11. Reduction of Dissolved Oxygen at a Copper Rotating Disc Electrode

    Science.gov (United States)

    Kear, Gareth; Albarran, Carlos Ponce-de-Leon; Walsh, Frank C.

    2005-01-01

    Undergraduates from chemical engineering, applied chemistry, and environmental science courses, together with first-year postgraduate research students in electrochemical technology, are provided with an experiment that demonstrates the reduction of dissolved oxygen in aerated seawater at 25°C. Oxygen reduction is examined using linear sweep…

  12. A new green approach for the reduction of graphene oxide ...

    Indian Academy of Sciences (India)

    A simple and green chemistry approach for the preparation of reduced graphene oxide nanosheets was successfully demonstrated through the reduction of graphene oxide (GO) using caffeine as the reductant. Without using toxic and harmful chemicals, this method is environmentally friendly and suitable for the large-scale ...

  13. Reductive Decouloristation of Dyes by Thermophilic Anaerobic Granular Sludge

    NARCIS (Netherlands)

    Bezerra Dos Santos, A.

    2005-01-01

    The colour removal achieved under anaerobic conditions is also called reductive decolourisation, which is composed of a biological part, i.e. the reducing equivalents are biologically generated, and a chemical part, i.e. the formed electrons reduce chemically the dyes. The overall objective of this

  14. Rapid and efficient galactose fermentation by engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Quarterman, Josh; Skerker, Jeffrey M; Feng, Xueyang; Liu, Ian Y; Zhao, Huimin; Arkin, Adam P; Jin, Yong-Su

    2016-07-10

    In the important industrial yeast Saccharomyces cerevisiae, galactose metabolism requires energy production by respiration; therefore, this yeast cannot metabolize galactose under strict anaerobic conditions. While the respiratory dependence of galactose metabolism provides benefits in terms of cell growth and population stability, it is not advantageous for producing fuels and chemicals since a substantial fraction of consumed galactose is converted to carbon dioxide. In order to force S. cerevisiae to use galactose without respiration, a subunit (COX9) of a respiratory enzyme was deleted, but the resulting deletion mutant (Δcox9) was impaired in terms of galactose assimilation. Interestingly, after serial sub-cultures on galactose, the mutant evolved rapidly and was able to use galactose via fermentation only. The evolved strain (JQ-G1) produced ethanol from galactose with a 94% increase in yield and 6.9-fold improvement in specific productivity as compared to the wild-type strain. (13)C-metabolic flux analysis demonstrated a three-fold reduction in carbon flux through the TCA cycle of the evolved mutant with redirection of flux toward the fermentation pathway. Genome sequencing of the JQ-G1 strain revealed a loss of function mutation in a master negative regulator of the Leloir pathway (Gal80p). The mutation (Glu348*) in Gal80p was found to act synergistically with deletion of COX9 for efficient galactose fermentation, and thus the double deletion mutant Δcox9Δgal80 produced ethanol 2.4 times faster and with 35% higher yield than a single knockout mutant with deletion of GAL80 alone. When we introduced a functional COX9 cassette back into the JQ-G1 strain, the JQ-G1-COX9 strain showed a 33% reduction in specific galactose uptake rate and a 49% reduction in specific ethanol production rate as compared to JQ-G1. The wild-type strain was also subjected to serial sub-cultures on galactose but we failed to isolate a mutant capable of utilizing galactose without

  15. [Reduction of hairiness of a transsexual person].

    Science.gov (United States)

    Karppinen, Ari

    2015-01-01

    Reduction of male pattern hairiness--especially facial hairiness--is important for the identity of a transsexual female. Methods of treatment include epilation, waxing, chemical depilation, planing, electrolysis, eflornitine cream and methods based on optical light. Also the hormonal therapies utilized in the treatment process reduce the degree of hairiness and make the hairs thinner. Instead of hair removal, one should rather speak of reducing hairiness, since life-long hairlessness is usually not achieved even by the most effective methods of hair reduction. Aspects affecting the choice of treatment include skin type, quality of hair, tolerability and availability of treatment, among other things.

  16. Large Scale Reduction of Graphite Oxide Project

    Science.gov (United States)

    Calle, Carlos; Mackey, Paul; Falker, John; Zeitlin, Nancy

    2015-01-01

    This project seeks to develop an optical method to reduce graphite oxide into graphene efficiently and in larger formats than currently available. Current reduction methods are expensive, time-consuming or restricted to small, limited formats. Graphene has potential uses in ultracapacitors, energy storage, solar cells, flexible and light-weight circuits, touch screens, and chemical sensors. In addition, graphite oxide is a sustainable material that can be produced from any form of carbon, making this method environmentally friendly and adaptable for in-situ reduction.

  17. Building a rapid response team.

    Science.gov (United States)

    Halvorsen, Lisa; Garolis, Salomeja; Wallace-Scroggs, Allyson; Stenstrom, Judy; Maunder, Richard

    2007-01-01

    The use of rapid response teams is a relatively new approach for decreasing or eliminating codes in acute care hospitals. Based on the principles of a code team for cardiac and/or respiratory arrest in non-critical care units, the rapid response teams have specially trained nursing, respiratory, and medical personnel to respond to calls from general care units to assess and manage decompensating or rapidly changing patients before their conditions escalate to a full code situation. This article describes the processes used to develop a rapid response team, clinical indicators for triggering a rapid response team call, topics addressed in an educational program for the rapid response team members, and methods for evaluating effectiveness of the rapid response team.

  18. Magnetically assisted chemical separation (MACS) process: Preparation and optimization of particles for removal of transuranic elements

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, L.; Kaminski, M.; Bradley, C.; Buchholz, B.A.; Aase, S.B.; Tuazon, H.E.; Vandegrift, G.F. [Argonne National Lab., IL (United States); Landsberger, S. [Univ. of Illinois, Urbana, IL (United States)

    1995-05-01

    The Magnetically Assisted Chemical Separation (MACS) process combines the selectivity afforded by solvent extractants with magnetic separation by using specially coated magnetic particles to provide a more efficient chemical separation of transuranic (TRU) elements, other radionuclides, and heavy metals from waste streams. Development of the MACS process uses chemical and physical techniques to elucidate the properties of particle coatings and the extent of radiolytic and chemical damage to the particles, and to optimize the stages of loading, extraction, and particle regeneration. This report describes the development of a separation process for TRU elements from various high-level waste streams. Polymer-coated ferromagnetic particles with an adsorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted with tributyl phosphate (TBP) were evaluated for use in the separation and recovery of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can then be recovered from the solution by using a magnet. The partition coefficients were larger than those expected based on liquid[liquid extractions, and the extraction proceeded with rapid kinetics. Extractants were stripped from the particles with alcohols and 400-fold volume reductions were achieved. Particles were more sensitive to acid hydrolysis than to radiolysis. Overall, the optimization of a suitable NMCS particle for TRU separation was achieved under simulant conditions, and a MACS unit is currently being designed for an in-lab demonstration.

  19. Problems of rapid growth.

    Science.gov (United States)

    Kim, T D

    1980-01-01

    South Korea's export-oriented development strategy has achieved a remarkable growth record, but it has also brought 2 different problems: 1) since the country's exports accounted for about 1% of total world export volume, the 1st world has become fearful about Korea's aggressive export drive; and 2) the fact that exports account for over 30% of its total gross national product (GNP) exposes the vulnerability of South Korea's economy itself. South Korea continues to be a poor nation, although it is rated as 1 of the most rapidly growing middle income economies. A World Bank 1978 report shows Korea to be 28th of 58 middle income countries in terms of per capita GNP in 1976. Of 11 newly industrializing countries (NIC), 5 in the European continent are more advanced than the others. A recent emphasis on the basic human needs approach has tended to downgrade the concept of GNP. Korea has only an abundant labor force and is without any natural resources. Consequently, Korea utilized an export-oriented development strategy. Oil requirements are met with imports, and almost all raw materials to be processed into exportable products must be imported. To pay import bills Korea must export and earn foreign exchange. It must be emphasized that foreign trade must always be 2-way traffic. In order to export more to middle income countries like Korea, the countries of the 1st world need to ease their protectionist measures against imports from developing countries.

  20. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  1. Rapidly rotating red giants

    Science.gov (United States)

    Gehan, Charlotte; Mosser, Benoît; Michel, Eric

    2017-10-01

    Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, wich behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the identification of mode crossings is precise and efficient. The determination of the mean core rotation directly derives from the precise measurement of the asymptotic period spacing ΔΠ1 and of the frequency at which the crossing of the rotational components is observed.

  2. Reducing Future International Chemical and Biological Dangers.

    Energy Technology Data Exchange (ETDEWEB)

    Haddal, Chad [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez, Patricia Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Foley, John T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    The International Biological and Chemical Threat Reduction Program at Sandia National Laboratories is developing a 15 - year technology road map in support the United States Government efforts to reduce international chemical and biological dangers . In 2017, the program leadership chartered an analysis team to explore dangers in the future international chemical and biological landscape through engagements with national security experts within and beyond Sandia to gain a multidisciplinary perspective on the future . This report offers a hi gh level landscape of future chemical and biological dangers based upon analysis of those engagements and provides support for further technology road map development.

  3. Work Truck Idling Reduction

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-03-01

    Hybrid utility trucks, with auxiliary power sources for on-board equipment, significantly reduce unnecessary idling resulting in fuel costs savings, less engine wear, and reduction in noise and emissions.

  4. Waste Reduction Model

    Science.gov (United States)

    To help solid waste planners and organizations track/report GHG emissions reductions from various waste management practices. To assist in calculating GHG emissions of baseline and alternative waste management practices and provide the history of WARM.

  5. Breast Reduction Surgery

    Science.gov (United States)

    ... to achieve a breast size proportionate to your body. Breast reduction surgery might also help improve your self-image and self-confidence and your ability to participate in physical activities. ...

  6. Medical Errors Reduction Initiative

    National Research Council Canada - National Science Library

    Mutter, Michael L

    2005-01-01

    The Valley Hospital of Ridgewood, New Jersey, is proposing to extend a limited but highly successful specimen management and medication administration medical errors reduction initiative on a hospital-wide basis...

  7. Bronchoscopic Lung Volume Reduction

    Directory of Open Access Journals (Sweden)

    Armin Ernst

    2011-01-01

    Full Text Available The application of lung volume reduction surgery in clinical practice is limited by high postoperative morbidity and stringent selection criteria. This has been the impetus for the development of bronchoscopic approaches to lung volume reduction. A range of different techniques such as endobronchial blockers, airway bypass, endobronchial valves, thermal vapor ablation, biological sealants, and airway implants have been employed on both homogeneous as well as heterogeneous emphysema. The currently available data on efficacy of bronchoscopic lung volume reduction are not conclusive and subjective benefit in dyspnoea scores is a more frequent finding than improvements on spirometry or exercise tolerance. Safety data are more promising with rare procedure-related mortality, few serious complications, and short hospital length of stay. The field of bronchoscopic lung volume reduction continues to evolve as ongoing prospective randomized trials build on earlier feasibility data to clarify the true efficacy of such techniques.

  8. Chemical looping for syngas & hydrogen production with parallel CO2 activation

    Science.gov (United States)

    More, Amey Sudhir

    The anticipated rise in global population and the rapidly growing economies of the developing world will dramatically increase the demand for consumer products, which are derived mostly from commodity chemicals. While the abundant natural gas (>95% CH4) reserves can potentially enable bulk chemical production, all commercial routes for methane (CH4) upgrading require its conversion to syngas (mixture of CO+H2) as a first step. Not only are current syngas production technologies highly energy and capital intensive, but they also result in large CO2 emissions. Overall, rising environmental concerns, increase demand for bulk chemicals and availability of abundant natural gas reserves together motivate the need to develop alternative processes for syngas production with CO2 utilization. 'Chemical Looping Combustion' is a clean combustion technology, which enables fossil fuel combustion with inherent CO2 capture based on the cyclic oxidation and reduction of an oxygen carrier. While most efforts in chemical looping (CL) are focused on combustion, we demonstrate the application of the "CL principle"--the periodic oxidation and reduction of a metal oxide to couple two independent redox reactions--to the activation of CO2 via reduction to CO (a chemical feedstock) and upgrading of CH4 to syngas or hydrogen. In this work, we investigate and compare CO2 activation via CL in two different operating modes: In the first scheme, CO2 reduction is coupled with CH4 oxidation by using mixtures of Fe and Ni (as alloys or simple physical mixtures) to produce CO and syngas product streams. In the second operating scheme, monometallic Ni carriers are utilized to catalytically crack CH4, producing pure H2 streams. The solid carbon deposits are then burnt off with CO2, overall producing separate CO and H2 product streams. Our investigations demonstrate the potential of CO2 as a "soft" oxidant which enables selective oxidation reactions in all the configurations, and thereby establish the

  9. Selective chemical stripping

    Science.gov (United States)

    Malavallon, Olivier

    1995-04-01

    At the end of the 80's, some of the large European airlines expressed a wish for paint systems with improved strippability on their aircraft, allowing the possibility to strip down to the primer without altering it, using 'mild' chemical strippers based on methylene chloride. These improvements were initially intended to reduce costs and stripping cycle times while facilitating rapid repainting, and this without the need to change the conventionally used industrial facilities. The level of in-service performance of these paint systems was to be the same as the previous ones. Requirements related to hygiene safety and the environment were added to these initial requirements. To meet customers' expectations, Aerospatiale, within the Airbus Industry GIE, formed a work group. This group was given the task of specifying, following up the elaboration and qualifying the paint systems allowing requirements to be met, in relation with the paint suppliers and the airlines. The analysis made in this report showed the interest of transferring as far upstream as possible (to paint conception level) most of the technical constraints related to stripping. Thus, the concept retained for the paint system, allowing selective chemical stripping, is a 3-coat system with characteristics as near as possible to the previously used paints.

  10. Pathogen reduction in human plasma using an ultrashort pulsed laser.

    Science.gov (United States)

    Tsen, Shaw-Wei D; Kingsley, David H; Kibler, Karen; Jacobs, Bert; Sizemore, Sara; Vaiana, Sara M; Anderson, Jeanne; Tsen, Kong-Thon; Achilefu, Samuel

    2014-01-01

    Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma.

  11. Pathogen reduction in human plasma using an ultrashort pulsed laser.

    Directory of Open Access Journals (Sweden)

    Shaw-Wei D Tsen

    Full Text Available Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma.

  12. CAMEO Chemicals Software

    Science.gov (United States)

    CAMEO Chemicals is an extensive chemical database, available for download, with critical response information for thousands of chemicals, and a tool that tells you what reactions might occur if chemicals were mixed together.

  13. Rapid response in psychological treatments for binge eating disorder.

    Science.gov (United States)

    Hilbert, Anja; Hildebrandt, Thomas; Agras, W Stewart; Wilfley, Denise E; Wilson, G Terence

    2015-06-01

    Analysis of short- and long-term effects of rapid response across 3 different treatments for binge eating disorder (BED). In a randomized clinical study comparing interpersonal psychotherapy (IPT), cognitive-behavioral therapy guided self-help (CBTgsh), and behavioral weight loss (BWL) treatment in 205 adults meeting Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; APA, 1994) criteria for BED, the predictive value of rapid response, defined as ≥70% reduction in binge eating by Week 4, was determined for remission from binge eating and global eating disorder psychopathology at posttreatment, 6-, 12-, 18-, and 24-month follow-ups. Rapid responders in CBTgsh, but not in IPT or BWL, showed significantly greater rates of remission from binge eating than nonrapid responders, which was sustained over the long term. Rapid and nonrapid responders in IPT and rapid responders in CBTgsh showed a greater remission from binge eating than nonrapid responders in CBTgsh and BWL. Rapid responders in CBTgsh showed greater remission from binge eating than rapid responders in BWL. Although rapid responders in all treatments had lower global eating disorder psychopathology than nonrapid responders in the short term, rapid responders in CBTgsh and IPT were more improved than those in BWL and nonrapid responders in each treatment. Rapid responders in BWL did not differ from nonrapid responders in CBTgsh and IPT. Rapid response is a treatment-specific positive prognostic indicator of sustained remission from binge eating in CBTgsh. Regarding an evidence-based, stepped-care model, IPT, equally efficacious for rapid and nonrapid responders, could be investigated as a second-line treatment in case of nonrapid response to first-line CBTgsh. (c) 2015 APA, all rights reserved).

  14. Inhibition of nitrification and carbon dioxide evolution as rapid tools ...

    African Journals Online (AJOL)

    Inhibition of nitrite formation and CO2 evolution displayed similar levels of sensitivities at 95% confidence levels. These results indicate that monitoring inhibition of metabolic processes rather than mortality was a more rapid and sensitive tool for ecotoxicological evaluation of chemicals employed in the petroleum industry in ...

  15. A rapid cloning method employing orthogonal end protection

    NARCIS (Netherlands)

    Jakobi, A.J.|info:eu-repo/dai/nl/311489621; Huizinga, E.G.|info:eu-repo/dai/nl/12314969X

    2012-01-01

    We describe a novel in vitro cloning strategy that combines standard tools in molecular biology with a basic protecting group concept to create a versatile framework for the rapid and seamless assembly of modular DNA building blocks into functional open reading frames. Analogous to chemical

  16. Selectfluor : A novel and efficient reagent for the rapid α ...

    Indian Academy of Sciences (India)

    A novel and efficient reagent for the rapid α-thiocyanation of ketones. DEZHEN WUa, XIAOJUAN YANGb and LIQIANG WUc,∗. aDepartment of Pharmacy, Xinxiang Central Hospital, Xinxiang, Henan 453000, China. bCollege of Chemistry and Chemical Engineering, Xinxiang University, Xinxiang, Henan 453003, China.

  17. Chemical properties of mendelevium

    Energy Technology Data Exchange (ETDEWEB)

    Hulet, E.K.

    1980-11-01

    Even with the most intense ion beams and the largest available quantities of target isotope, about 10/sup 6/ atoms at a time is all the Md that can be produced for chemical studies. This lack of sufficient sample size coupled with the very short lifetimes of the few atoms produced has severely restricted the gathering and the broadness of our knowledge concerning the properties of Md and the heavier elements. To illustrate, the literature contains a mere eleven references to the chemical studies of Md, and none of these deal with bulk properties associated with the element bound in solid phases. Some of these findings are: Md was found to be more volatile than other actinide metals which lead to the belief that it is divalent in the metallic state; separation of Md from the other actinides can be accomplished either by reduction of Md/sup 3 +/ to the divalent state or by chromatographic separations with Md remaining in the tripositive state; extraction of Md/sup 2 +/ with bis(2-ethylhexyl)phosphoric acid is much poorer than the extraction of the neighboring tripositive actinides; attempts to oxidize Md/sup 3 +/ with sodium bismuthate failed to show any evidence for Md/sup 4 +/; reduction potential of Md/sup 3 +/ was found to be close to -0.1 volt; Md/sup 3 +/ can be reduced to Md(Hg) by sodium amalgams and by electrolysis; the electrochemical behavior of Md is very similar to that of Fm and can be summarized in the equation, Md/sup 2 +/ + 2e/sup -/ = Md(Hg) and E/sup 0/ = -1.50 V.; and Md cannot be reduced to a monovalent ion with Sm/sup 2 +/.

  18. Bioinspired Chemical Communication between Synthetic Nanomotors.

    Science.gov (United States)

    Chen, Chuanrui; Chang, Xiaocong; Teymourian, Hazhir; Ramírez-Herrera, Doris E; Esteban-Fernández de Ávila, Berta; Lu, Xiaolong; Li, Jinxing; He, Sha; Fang, Chengcheng; Liang, Yuyan; Mou, Fangzhi; Guan, Jianguo; Wang, Joseph

    2018-01-02

    While chemical communication plays a key role in diverse natural processes, the intelligent chemical communication between synthetic nanomotors remains unexplored. The design and operation of bioinspired synthetic nanomotors is presented. Chemical communication between nanomotors is possible and has an influence on propulsion behavior. A chemical "message" is sent from a moving activator motor to a nearby activated (receiver) motor by release of Ag+ ions from a Janus polystyrene/Ni/Au/Ag activator motor to the activated Janus SiO2 /Pt nanomotor. The transmitted silver signal is translated rapidly into a dramatic speed change associated with the enhanced catalytic activity of activated motors. Selective and successive activation of multiple nanomotors is achieved by sequential localized chemical communications. The concept of establishing chemical communication between different synthetic nanomotors paves the way to intelligent nanoscale robotic systems that are capable of cooperating with each other. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The genomic landscape of rapid repeated evolutionary ...

    Science.gov (United States)

    Atlantic killifish populations have rapidly adapted to normally lethal levels of pollution in four urban estuaries. Through analysis of 384 whole killifish genome sequences and comparative transcriptomics in four pairs of sensitive and tolerant populations, we identify the aryl hydrocarbon receptor–based signaling pathway as a shared target of selection. This suggests evolutionary constraint on adaptive solutions to complex toxicant mixtures at each site. However, distinct molecular variants apparently contribute to adaptive pathway modification among tolerant populations. Selection also targets other toxicity-mediatinggenes and genes of connected signaling pathways; this indicates complex tolerance phenotypes and potentially compensatory adaptations. Molecular changes are consistent with selection on standing genetic variation. In killifish, high nucleotide diversityhas likely been a crucial substrate for selective sweeps to propel rapid adaptation. This manuscript describes genomic evaluations that contribute to our understanding of the ecological and evolutionary risks associated with chronic contaminant exposures to wildlife populations. Here, we assessed genetic patterns associated with long-term response to an important class of highly toxic environmental pollutants. Specifically, chemical-specific tolerance has rapidly and repeatedly evolved in an estuarine fish species resident to estuaries of the Atlantic U.S. coast. We used laboratory studies to ch

  20. Elimination of enteric bacteria in biological-chemical wastewater treatment and tertiary filtration units.

    Science.gov (United States)

    Koivunen, Jari; Siitonen, Anja; Heinonen-Tanski, Helvi

    2003-02-01

    The occurrence and removal of salmonellae and faecal indicators in four conventional municipal wastewater treatment plants (MWTP) were investigated. In addition, we tested the efficiency of a semi-technical scale biological nutrient removal process and three pilot-scale tertiary filtration units in microbial removal. All influent samples collected from MWTPs contained salmonellae from 93 to 11,000 MPN/100 ml and indicator bacteria from about 10(7) to 10(8) CFU/100 ml. The reductions in salmonella numbers achieved in full-scale biological-chemical wastewater treatment and semi-technical scale biological nutrient removal processes were usually between 94% and virtually 100% (99.9%) and indicator bacteria reductions between 2 and 3 log units. Microbial numbers in MWTP effluents could be modelled as a function of effluent residual organic matter, suspended solids and total phosphorus concentrations. Pilot-scale tertiary treatment by rapid sand contact filter, chemical contact filter and biological-chemical contact filter reduced salmonella numbers below the detection limit and faecal coliform numbers on average by 99%, 39% and 71%, respectively. A total of 32 Salmonella serovars were identified among 197 Salmonella isolates from municipal wastewaters. Of the isolates, 32% were resistant to nalidixic acid, indicating reduced sensitivity to ciprofloxacin, the drug of choice in the treatment of salmonellosis. In addition, 18% of the isolates were multiresistant. Our results, especially antibiotic resistant Salmonella strains, indicate that conventional municipal wastewater treatment without efficient tertiary treatment, like filtration or disinfection, may constitute a risk for public health.

  1. Rapid Active Sampling Package

    Science.gov (United States)

    Peters, Gregory

    2010-01-01

    A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni

  2. Limonene: a versatile chemical of the bioeconomy.

    Science.gov (United States)

    Ciriminna, Rosaria; Lomeli-Rodriguez, Monica; Demma Carà, Piera; Lopez-Sanchez, Jose A; Pagliaro, Mario

    2014-12-18

    (+)-Limonene is a renewable chemical with numerous and growing applications. Its traditional uses such as flavor, fragrance and green solvent are rapidly expanding to include its utilization as a platform chemical, extraction solvent for natural products and an active agent for functionalized products. We anticipate that the expansion in uses for limonene will translate into increasing production and use of this relevant natural product, especially for advanced applications.

  3. Fifty years of Chemical Physics Letters

    Science.gov (United States)

    Buckingham, A. David

    2017-09-01

    Chemical Physics Letters was born in 1967. In the first Number, published in February that year, the Founding Editors, Jan Hoytink and Laurens Jansen, stipulated that the journal would be truly international and that all submitted papers will be refereed. The aim was to provide a convenient means for the rapid dissemination of research results in the field of chemical physics. There would be an emphasis on theoretical interpretation. This article reviews the progress of the journal over its first fifty years.

  4. Rapid Robot Design Validation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies will create a comprehensive software infrastructure for rapid validation of robotic designs. The software will support push-button validation...

  5. Rapid Robot Design Validation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies will create a comprehensive software infrastructure for rapid validation of robot designs. The software will support push-button validation...

  6. Microbial reduction of iron in smectite

    Science.gov (United States)

    Stucki, Joseph W.; Kostka, Joel E.

    2006-06-01

    Bacteria-mediated changes in the oxidation state of iron in soil clay minerals play an important role in determining the chemical and physical properties of soils and sediments. As structural Fe(III) in the octahedral sheet of smectites is reduced to Fe(II) by bacteria, specific surface area decreases, cation exchange capacity (CEC) increases, swelling in water decreases, reactivity with organic chemicals and pesticides increases, and the potential for mineral dissolution and transformation increases. Changes in clay mineral structure due to bacterial reduction is, however, small. Because of the large potential for the redox state of soil minerals to change with natural environmental conditions, the chemical properties of the soil must be regarded as constantly changing. The resulting dynamic nature of soil behavior must be taken into account in management strategies to maximize soil fertility and structural performance. To cite this article: J.W. Stucki, J.E. Kostka, C. R. Geoscience 338 (2006).

  7. Rapid Color Test Identification System for Screening of Counterfeit Fluoroquinolone

    Directory of Open Access Journals (Sweden)

    B. K. Singh

    2009-01-01

    Full Text Available The protocol of rapid identification system consists of three chemical color reactions; two group tests for fluoroquinolone class and a compound specific test each for norfloxacin, ciprofloxacin, gatifloxacin, ofloxacin, levofloxacin and sparfloxacin. The group color reactions are based on (a Oxidizing behavior of quinolone and (b Fluorine functional groups, both of which are characteristic of fluoroquinolone class. The compound specific color reactions are developed taking into consideration unique chemical behavior of each compound. The proposed chemical color tests have high selectivity⁄specificity, are ideal for screening purpose. The color of each test was defined by two standard color systems namely CIE lab and Munsell color. A suspected counterfeit tablet of any of the above mentioned drugs can be identified within 10-15 min using this rapid identification system.

  8. Harm Reduction Behind Bars

    Directory of Open Access Journals (Sweden)

    Emma R. Miller

    2013-06-01

    Full Text Available We aimed to identify how strategies to reduce the risk of hepatitis C virus (HCV in prisons could be implemented in a way that is acceptable to those with the responsibility for implementing them. Prison officer and nurse perceptions of HCV and attitudes toward a range of harm reduction interventions, including clean needle and bleach provision, were explored. In the context of highly prevalent feelings of resentment, most of the proposed strategies were perceived by all staff as a threat for officers and a privilege for prisoners. Addressing the underlying concerns of prison staff is essential in achieving a fully collaborative harm reduction effort. Ongoing resistance to proposed harm reduction strategies underscores the relevance of these findings for prison settings in Australia and elsewhere.

  9. Bronchoscopic lung volume reduction

    Directory of Open Access Journals (Sweden)

    M. I. Polkey

    2006-12-01

    Full Text Available Surgical lung volume reduction can improve exercise performance and forced expiratory volume in one second in patients with emphysema. However, the procedure is associated with a 5% mortality rate and a nonresponse rate of 25%. Accordingly, interest has focused on alternative ways of reducing lung volume. Two principle approaches are used: collapse of the diseased area using blockers placed endobronchially and the creation of extrapulmonary pathways. Preliminary data from the former approach suggest that it can be successful and that the magnitude of success is related to reduction in dynamic hyperinflation.

  10. REDUCTIONS WITHOUT REGRET: SUMMARY

    Energy Technology Data Exchange (ETDEWEB)

    Swegle, J.; Tincher, D.

    2013-09-16

    This paper briefly summarizes the series in which we consider the possibilities for losing, or compromising, key capabilities of the U.S. nuclear force in the face of modernization and reductions. The first of the three papers takes an historical perspective, considering capabilities that were eliminated in past force reductions. The second paper is our attempt to define the needed capabilities looking forward in the context of the current framework for force modernization and the current picture of the evolving challenges of deterrence and assurance. The third paper then provides an example for each of our undesirable outcomes: the creation of roach motels, box canyons, and wrong turns.

  11. Rapid prototyping in medical sciences

    Directory of Open Access Journals (Sweden)

    Ákos Márk Horváth

    2015-09-01

    Full Text Available Even if it sound a bit incredible rapid prototyping (RPT as production method has been used for decades in other professions. Nevertheless medical science just started discover the possibilities of this technology and use the offered benefits of 3D printing. In this paper authors have investigated the pharmaceutical usage of rapid prototyping.

  12. Study of the reduction in detection limits of track detectors used for {sup 10}B(n,α){sup 7}Li reaction rate measure through annealing and chemical etching experiments; Estudo da reducao nos limites de deteccao de detectores de tracos utilizados na medida de taxa de reacao {sup 10}B(n, α){sup 7}Li atraves de experimentos de annealing e ataque quimico

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcellos, Herminiane L.; Smilgys, Barbara; Guedes, Sandro, E-mail: hluizav@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Castro, Vinicius A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2013-08-15

    The Boron Neutron Capture Therapy (BNCT) is an experimental radiotherapy for cancer treatment. It is based on {sup 10}B(n, α){sup 7}Li reaction, which can be measured by track detectors capable of recording events that strike them. With this recording, it is possible to determine the number of alpha particles and recoiling Lithium-7 nucleus, reaction products, and from this information, which amount of radiation dose a patient is exposed to. In this work, PADC detectors were characterized, irradiated at the IEA-R1 IPEN/CNEN reactor to assess the contribution of the{sup 10}B(n, α){sup 7}Li reaction and protons from fast neutron scattering with the elements that compounds the tissue. With the aim of reducing the proton background, the detectors were subjected to heating experiments at 80°C for periods in the range 0-100 hours. This was done in order to restore partially modified structure of the detector, causing a reduction in the size and density of tracks. This effect is known as annealing. For the visualization of tracks at microscope, detectors were made three chemical attacks with sodium hydroxide (NaOH) for 30, 60 and 90 minutes at 70°C. It was observed a reduction in the track density achieving a plateau heating time of 50 hours. For detectors that have not undergone annealing and were etched with another etchant, PEW solution, a reduction of 87% in track density was obtained. (author)

  13. THE CHEMICAL TECHNOLOGIES OF SOIL’S DECONTAMINATION

    Directory of Open Access Journals (Sweden)

    Roxana – Gabriela POPA

    2017-12-01

    Full Text Available The chemical soil degradation technologies are based on the pollutant conversion and immobilisation, or the mobilization, extraction and washing of pollutants. They use chemical agents that oxidize or reduce pollutants to less toxic or non-toxic forms and immobilize them in the underground environment in order to diminish their migration and the extent of pollution. Classification of chemical methods of depollution is based on the dominant reaction criterion: oxidation, reduction, neutralization, precipitation, chemical extraction, hydrolysis, dehalogenation, precipitation.

  14. Using a Microscale Approach to Rapidly Separate and Characterize Three Photosynthetic Pigment Species from Fern

    Science.gov (United States)

    Ayudhya, Theppawut Israsena Na; Posey, Frederick T.; Tyus, Jessica C.; Dingra, Nin N.

    2015-01-01

    A rapid separation of three photosynthetic pigments (chlorophyll "a" and "b" and xanthophyll) from fern ("Polystichum acrostichoides") is described using microscale solvent extraction and traditional thin layer chromatography that minimizes use of harmful chemicals and lengthy procedures. The experiment introduces…

  15. Rapid Near Infra-red Reflectance Analysis (NIRA) of Mainstream Smoke Collected on Cambridge Filter Pads

    National Research Council Canada - National Science Library

    C DiLuzio; S Morzilli; E Cardinale

    Near infra-red (NIR) reflectance spectroscopy has been used for rapidly and reproducibly measuring the NIR spectra of mainstream smoke collected on Cambridge filter pads and quantifying the chemical composition from the spectral data...

  16. (MTT) dye reduction assay.

    African Journals Online (AJOL)

    to inhibit proliferation of HeLa cells was determined using the 3443- dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) dye reduction assay. Extracts from roots of Agathisanthemum bojeri, Synaptolepis kirkii and Zanha africana and the leaf extract of Physalis peruviana at a concentration of 10 pg/ml inhibited cell ...

  17. Method I : Planar reduction

    NARCIS (Netherlands)

    Broer, H.; Hoveijn, I.; Lunter, G.; Vegter, G.

    2003-01-01

    We apply the planar reduction method to a general two degree of freedom system with optional symmetry, near equilibrium and close to resonance. As a leading example the spring-pendulum close to 1:2 resonance is used. The resulting planar model is computed explicitly, and the bifurcation curves

  18. Cold plasma rapid decontamination of food contact surfaces contaminated with Salmonella biofilms.

    Science.gov (United States)

    Niemira, Brendan A; Boyd, Glenn; Sites, Joseph

    2014-05-01

    Cross-contamination of foods from persistent pathogen reservoirs is a known risk factor in processing environments. Industry requires a rapid, waterless, zero-contact, chemical-free method for removing pathogens from food contact surfaces. Cold plasma was tested for its ability to inactivate Salmonella biofilms. A 3-strain Salmonella culture was grown to form adherent biofilms for 24, 48, or 72 h on a test surface (glass slides). These were placed on a conveyor belt and passed at various line speeds to provide exposure times of 5, 10, or 15 s. The test plate was either 5 or 7.5 cm under a plasma jet emitter operating at 1 atm using filtered air as the feed gas. The frequency of high-voltage electricity was varied from 23 to 48 kHz. At the closer spacing (5 cm), cold plasma reduced Salmonella biofilms by up to 1.57 log CFU/mL (5 s), 1.82 log CFU/mL (10 s), and 2.13 log CFU/mL (15 s). Increasing the distance to 7.5 cm generally reduced the efficacy of the 15 s treatment, but had variable effects on the 5 and 10 s treatments. Variation of the high-voltage electricity had a greater effect on 10 and 15 s treatments, particularly at the 7.5 cm spacing. For each combination of time, distance, and frequency, Salmonella biofilms of 24, 48, and 72 h growth responded consistently with each other. The results show that short treatments with cold plasma yielded up to a 2.13 log reduction of a durable form of Salmonella contamination on a model food contact surface. This technology shows promise as a possible tool for rapid disinfection of materials associated with food processing. Pathogens such as Salmonella can form chemical-resistant biofilms, making them difficult to remove from food contact surfaces. A 15 s treatment with cold plasma reduced mature Salmonella biofilms by up to 2.13 log CFU/mL (99.3%). This contact-free, waterless method uses no chemical sanitizers. Cold plasma may therefore have a practical application for conveyor belts, equipment, and other food contact

  19. Radioactive wastes: the challenge of volumes reduction; Dechets radioactifs: le defi de la reduction des volumes

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, V

    2005-11-01

    The reduction of radioactive waste volumes is a priority for the French atomic energy commission (CEA) and for the Areva group. This article gives a rapid overview of the equipments and processes used to separate the valorizable materials from the ultimate wastes: pulsed separation columns and evaporators for the liquid-liquid extraction, compactification of spent fuel hulls, remote handling systems, recoverable colloid for surface decontamination, decontaminating foam, hydrothermal oxidation of organic and aqueous effluents, cold crucible vitrification etc. (J.S.)

  20. Students' conceptions of chemical change

    Science.gov (United States)

    Hesse, Joseph J., III; Anderson, Charles W.

    One hundred high school chemistry students who had completed a unit on chemical change were given a written instrument in which they were shown three oxidation-reduction reactions and were asked to explain them. Eleven students representing a range of achievement levels were chosen for more intensive clinical interviews in which they explained their responses, evaluated the quality of their responses, and compared them to other hypothetical responses. Interview results revealed that students commonly experienced difficulties at three different epistemological levels:1. Chemical knowledge. Most students failed to invoke atoms and molecules as explanatory constructs, even though they had been emphasized in their chemistry course. Some students also listed substances such as heat, cold, or decay as reactants or products.2. Conservation reasoning. Many students could not predict or explain mass changes in the chemical reactions. Their most common problems included (a) a tendency to treat chemical changes such as rusting as physical changes in form or state, and (b) failure to understand the role of invisible (in this case gaseous) reactants or products in the reactions.3. Explanatory ideals. Many students demonstrated a preference for explanations based on superficial analogies with everyday events (e.g., rusting is like decay) over explanations based on chemical theories.Only one of the 11 students interviewed demonstrated mastery of the unit's contents at all three levels. Results of this and other research indicate a need for substantial revision in chemistry teaching practice.