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Sample records for concentrations selectively generates

  1. A flow system for generation of concentration perturbation in two-dimensional correlation near-infrared spectroscopy: application to variable selection in multivariate calibration.

    PubMed

    Pereira, Claudete Fernandes; Pasquini, Celio

    2010-05-01

    A flow system is proposed to produce a concentration perturbation in liquid samples, aiming at the generation of two-dimensional correlation near-infrared spectra. The system presents advantages in relation to batch systems employed for the same purpose: the experiments are accomplished in a closed system; application of perturbation is rapid and easy; and the experiments can be carried out with micro-scale volumes. The perturbation system has been evaluated in the investigation and selection of relevant variables for multivariate calibration models for the determination of quality parameters of gasoline, including ethanol content, MON (motor octane number), and RON (research octane number). The main advantage of this variable selection approach is the direct association between spectral features and chemical composition, allowing easy interpretation of the regression models. PMID:20482969

  2. Modeling of concentrating solar thermoelectric generators

    NASA Astrophysics Data System (ADS)

    McEnaney, Kenneth; Kraemer, Daniel; Ren, Zhifeng; Chen, Gang

    2011-10-01

    The conversion of solar power into electricity is dominated by non-concentrating photovoltaics and concentrating solar thermal systems. Recently, it has been shown that solar thermoelectric generators (STEGs) are a viable alternative in the non-concentrating regime. This paper addresses the possibility of STEGs being used as the power block in concentrating solar power systems. STEG power blocks have no moving parts, they are scalable, and they eliminate the need for an external traditional thermomechanical generator, such as a steam turbine or Stirling engine. Using existing skutterudite and bismuth telluride materials, concentrating STEGs can have efficiencies exceeding 10% based on a geometric optical concentration ratio of 45.

  3. Solar steam generation: Steam by thermal concentration

    NASA Astrophysics Data System (ADS)

    Shang, Wen; Deng, Tao

    2016-09-01

    The solar-driven generation of water steam at 100 °C under one sun normally requires the use of optical concentrators to provide the necessary energy flux. Now, thermal concentration is used to raise the vapour temperature to 100 °C without the need for costly optical concentrators.

  4. Fourth-generation photovoltaic concentrator system development

    SciTech Connect

    O`Neill, M.J.; McDanal, A.J.

    1995-10-01

    In 1991, under a contract with Sandia for the Concentrator Initiative, the ENTECH team initiated the design and development of a fourth-generation concentrator module. In 1992, Sandia also contracted with ENTECH to develop a new control and drive system for the ENTECH array. This report documents the design and development work performed under both contracts. Manufacturing processes for the new module were developed at the same time under a complementary PVMaT contract with the National Renewable Energy Laboratory. Two 100-kW power plants were deployed in 1995 in Texas using the newly developed fourth-generation concentrator technology, one at the CSW Solar Park near Ft. Davis and one at TUE Energy Park in Dallas. Technology developed under the Sandia contracts has made a successful transition from the laboratory to the production line to the field.

  5. Critical Concentration Ratio for Solar Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    ur Rehman, Naveed; Siddiqui, Mubashir Ali

    2016-06-01

    A correlation for determining the critical concentration ratio (CCR) of solar concentrated thermoelectric generators (SCTEGs) has been established, and the significance of the contributing parameters is discussed in detail. For any SCTEG, higher concentration ratio leads to higher temperatures at the hot side of modules. However, the maximum value of this temperature for safe operation is limited by the material properties of the modules and should be considered as an important design constraint. Taking into account this limitation, the CCR can be defined as the maximum concentration ratio usable for a particular SCTEG. The established correlation is based on factors associated with the material and geometric properties of modules, thermal characteristics of the receiver, installation site attributes, and thermal and electrical operating conditions. To reduce the number of terms in the correlation, these factors are combined to form dimensionless groups by applying the Buckingham Pi theorem. A correlation model containing these groups is proposed and fit to a dataset obtained by simulating a thermodynamic (physical) model over sampled values acquired by applying the Latin hypercube sampling (LHS) technique over a realistic distribution of factors. The coefficient of determination and relative error are found to be 97% and ±20%, respectively. The correlation is validated by comparing the predicted results with literature values. In addition, the significance and effects of the Pi groups on the CCR are evaluated and thoroughly discussed. This study will lead to a wide range of opportunities regarding design and optimization of SCTEGs.

  6. Critical Concentration Ratio for Solar Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    ur Rehman, Naveed; Siddiqui, Mubashir Ali

    2016-10-01

    A correlation for determining the critical concentration ratio (CCR) of solar concentrated thermoelectric generators (SCTEGs) has been established, and the significance of the contributing parameters is discussed in detail. For any SCTEG, higher concentration ratio leads to higher temperatures at the hot side of modules. However, the maximum value of this temperature for safe operation is limited by the material properties of the modules and should be considered as an important design constraint. Taking into account this limitation, the CCR can be defined as the maximum concentration ratio usable for a particular SCTEG. The established correlation is based on factors associated with the material and geometric properties of modules, thermal characteristics of the receiver, installation site attributes, and thermal and electrical operating conditions. To reduce the number of terms in the correlation, these factors are combined to form dimensionless groups by applying the Buckingham Pi theorem. A correlation model containing these groups is proposed and fit to a dataset obtained by simulating a thermodynamic (physical) model over sampled values acquired by applying the Latin hypercube sampling (LHS) technique over a realistic distribution of factors. The coefficient of determination and relative error are found to be 97% and ±20%, respectively. The correlation is validated by comparing the predicted results with literature values. In addition, the significance and effects of the Pi groups on the CCR are evaluated and thoroughly discussed. This study will lead to a wide range of opportunities regarding design and optimization of SCTEGs.

  7. High-Temperature, High-Concentration Solar Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Warren, Emily; Baranowski, Lauryn; Olsen, Michele; Ndione, Paul; Netter, Judy; Goodrich, Alan; Gray, Matthew; Parilla, Philip; Ginley, David; Toberer, Eric

    2014-03-01

    Solar thermoelectric generators (STEGs) powered with concentrated solar energy have potential for use as primary energy converters or as topping-cycles for more conventional concentrated solar power (CSP) technologies. Modeling based on current record modules from JPL suggests thermoelectric efficiencies of 18 % could be experimentally expected with a temperature gradient of 1000 - 100°C. Integrating these state-of-the-art TEGs with a concentrating solar receiver requires simultaneous optimization of optical, thermal, and thermoelectric systems. This talk will discuss the modeling, design, and experimental testing of STEG devices under concentrated sunlight. We have developed a model that combines thermal circuit modeling with optical ray tracing to design selective absorber coatings and cavities to minimize radiation losses from the system. We have fabricated selective absorber coatings and demonstrated that these selective absorber films can minimize blackbody radiation losses at high temperature and are stable after thermal cycling to 1000°C. On-sun testing of STEG devices and thermal simulators is ongoing and preliminary results will be discussed.

  8. Genetic Changes with Generations of Artificial Selection

    PubMed Central

    Silvela, Luis

    1980-01-01

    Using conditional probabilities and moment-generating matrices, I derived approximate algebraic equations that give expectations of gene frequency, population mean, gene frequency variance within lines, or heterozygosity, and gene frequency variance between lines, or drift, for repeated cycles of recurrent selection in populations of finite size. For genes of large effect, the responses to selection differ substantially from the classical expectations, and equations are derived that give quantitative estimates of asymmetry of response when selection is done in opposite directions. Particular cases of the derived formulae yield equations given by other authors. The error involved in the approximations is discussed in the appendix. PMID:17249050

  9. Minimal selective concentrations of tetracycline in complex aquatic bacterial biofilms.

    PubMed

    Lundström, Sara V; Östman, Marcus; Bengtsson-Palme, Johan; Rutgersson, Carolin; Thoudal, Malin; Sircar, Triranta; Blanck, Hans; Eriksson, K Martin; Tysklind, Mats; Flach, Carl-Fredrik; Larsson, D G Joakim

    2016-05-15

    Selection pressure generated by antibiotics released into the environment could enrich for antibiotic resistance genes and antibiotic resistant bacteria, thereby increasing the risk for transmission to humans and animals. Tetracyclines comprise an antibiotic class of great importance to both human and animal health. Accordingly, residues of tetracycline are commonly detected in aquatic environments. To assess if tetracycline pollution in aquatic environments promotes development of resistance, we determined minimal selective concentrations (MSCs) in biofilms of complex aquatic bacterial communities using both phenotypic and genotypic assays. Tetracycline significantly increased the relative abundance of resistant bacteria at 10 μg/L, while specific tet genes (tetA and tetG) increased significantly at the lowest concentration tested (1 μg/L). Taxonomic composition of the biofilm communities was altered with increasing tetracycline concentrations. Metagenomic analysis revealed a concurrent increase of several tet genes and a range of other genes providing resistance to different classes of antibiotics (e.g. cmlA, floR, sul1, and mphA), indicating potential for co-selection. Consequently, MSCs for the tet genes of ≤ 1 μg/L suggests that current exposure levels in e.g. sewage treatment plants could be sufficient to promote resistance. The methodology used here to assess MSCs could be applied in risk assessment of other antibiotics as well. PMID:26938321

  10. Minimal selective concentrations of tetracycline in complex aquatic bacterial biofilms.

    PubMed

    Lundström, Sara V; Östman, Marcus; Bengtsson-Palme, Johan; Rutgersson, Carolin; Thoudal, Malin; Sircar, Triranta; Blanck, Hans; Eriksson, K Martin; Tysklind, Mats; Flach, Carl-Fredrik; Larsson, D G Joakim

    2016-05-15

    Selection pressure generated by antibiotics released into the environment could enrich for antibiotic resistance genes and antibiotic resistant bacteria, thereby increasing the risk for transmission to humans and animals. Tetracyclines comprise an antibiotic class of great importance to both human and animal health. Accordingly, residues of tetracycline are commonly detected in aquatic environments. To assess if tetracycline pollution in aquatic environments promotes development of resistance, we determined minimal selective concentrations (MSCs) in biofilms of complex aquatic bacterial communities using both phenotypic and genotypic assays. Tetracycline significantly increased the relative abundance of resistant bacteria at 10 μg/L, while specific tet genes (tetA and tetG) increased significantly at the lowest concentration tested (1 μg/L). Taxonomic composition of the biofilm communities was altered with increasing tetracycline concentrations. Metagenomic analysis revealed a concurrent increase of several tet genes and a range of other genes providing resistance to different classes of antibiotics (e.g. cmlA, floR, sul1, and mphA), indicating potential for co-selection. Consequently, MSCs for the tet genes of ≤ 1 μg/L suggests that current exposure levels in e.g. sewage treatment plants could be sufficient to promote resistance. The methodology used here to assess MSCs could be applied in risk assessment of other antibiotics as well.

  11. Low chemical concentrating steam generating cycle

    DOEpatents

    Mangus, James D.

    1983-01-01

    A steam cycle for a nuclear power plant having two optional modes of operation. A once-through mode of operation uses direct feed of coolant water to an evaporator avoiding excessive chemical concentration buildup. A recirculation mode of operation uses a recirculation loop to direct a portion of flow from the evaporator back through the evaporator to effectively increase evaporator flow.

  12. Thermophotovoltaic Generators Using Selective Metallic Emitters

    NASA Technical Reports Server (NTRS)

    Fraas, Lewis M.; Samaras, John E.; Avery, James E.; Ewell, Richard

    1995-01-01

    In the literature to date on thermophotovoltaic (TPV) generators, two types of infrared emitter's have been emphasized : gray body emitters and rare earth oxide selective emitters. The gray body emitter is defined as an emitter with a spectral emissivity independent of wavelength whereas the rare earth oxide selective emitter is idealized as a delta function emitter with a high emissivity at a select wavelength and a near zero emissivity at all other wavelengths. Silicon carbide is an example of a gray body emitter and ER-YAG is an example of a selective emitter. The Welsbach mantle in a common lantern is another example of an oxide selective emitter. Herein, we describe an alternative type of selective emitter, a selective metallic emitter. These metallic emitters are characterized by a spectral emissivity curve wherein the emissivity monotonically increases with shorter infrared wavelengths as is shown. The metal of curve "A", tungsten, typifies this class of selective metallic emitter's. In a thermophotovoltaic generator, a photovoltaic cell typically converts infrared radiation to electricity out to some cut-off wavelength. For example, Gallium Antimonide (GaSb) TPV cells respond out to 1.7 microns. The problem with gray body emitters is that they emit at all wavelengths. Therefore, a large fraction of the energy emitted will be outside of the response band of the TPV cell. The argument for the selective emitter is that, ideally, all the emitted energy can be in the cells response band. Unfortunately, rare earth oxide emitters are not ideal. In order to suppress the emissivity toward zero away from the select wavelength, the use of thin fiber's is necessary. This leads to a fragile emitter typical of a lantern mantle. Even given a thin ER-YAG emitter, the measured emissivity at the select wavelength of 1.5 microns has been reported to be 0.6 while the off wavelength background emissivity falls to only 0.2 at 5 microns. This gives a selectivity ratio of only 3

  13. Selection of antibiotic resistance at very low antibiotic concentrations.

    PubMed

    Sandegren, Linus

    2014-05-01

    Human use of antibiotics has driven the selective enrichment of pathogenic bacteria resistant to clinically used drugs. Traditionally, the selection of resistance has been considered to occur mainly at high, therapeutic levels of antibiotics, but we are now beginning to understand better the importance of selection of resistance at low levels of antibiotics. The concentration of an antibiotic varies in different body compartments during treatment, and low concentrations of antibiotics are found in sewage water, soils, and many water environments due to natural production and contamination from human activities. Selection of resistance at non-lethal antibiotic concentrations (below the wild-type minimum inhibitory concentration) occurs due to differences in growth rate at the particular antibiotic concentration between cells with different tolerance levels to the antibiotic. The minimum selective concentration for a particular antibiotic is reached when its reducing effect on growth of the susceptible strain balances the reducing effect (fitness cost) of the resistance determinant in the resistant strain. Recent studies have shown that resistant bacteria can be selected at concentrations several hundred-fold below the lethal concentrations for susceptible cells. Resistant mutants selected at low antibiotic concentrations are generally more fit than those selected at high concentrations but can still be highly resistant. The characteristics of selection at low antibiotic concentrations, the potential clinical problems of this mode of selection, and potential solutions will be discussed.

  14. Investigation of radioactivity concentration in spent technetium generators

    NASA Astrophysics Data System (ADS)

    Idriss, Hajo; Salih, Isam; Alaamer, Abdulaziz S.; Eisa, M. H.; Sam, A. K.

    2014-04-01

    This study was carried out to survey and measure radioactivity concentration and estimate radiation dose level at the surface of spent technetium generator columns for the safe final disposal of radioactive waste. High resolution γ-spectrometry with the aid of handheld radiation survey meters has been used. The radioactivity measurements has shown that 238U, 40K and 137Cs were only measurable in one sample whereas 125Sb was found in 14 samples out of total of 20 samples with an activity concentration which ranged from 21 to 7404 with an average value of 1095 Bq/kg. The activity concentration of 125Sb is highly variable indicating that the spent 99mTc generator columns are of different origin. This investigation highlighted the importance of radiation monitoring of spent technetium generators in the country in order to protect workers, and the public from the dangers posed by radioactive waste.

  15. Direct-Drive Contactless Wind Generator with Concentrated Winding

    NASA Astrophysics Data System (ADS)

    Levin, N.; Pugachov, V.; Orlova, S.

    2012-01-01

    A clear trend has emerged in the field of wind power industry concerning the creation of low-, medium-, and even high-power direct-drive wind turbines without the use of gearboxes. Such generators are usually multipolar and mostly excited from permanent magnets. In the low-speed performance, multipolarity means a higher specific torque and reliability as well as lower operating costs, which in the case of high-speed generators is hindered by gearboxes. Multipolarity with a high specific torque can be achieved mainly through the use of permanent magnets of high-energy materials (such as NdFeB) and through design solutions for the armature winding. The authors compare two most common types of wind generator's armature windings: the distributed one, which contains a coil embracing several teeth, and the concentrated armature winding - with one coil for one stator tooth. The comparison (along with the experience in developing the wind turbines) shows that the con-centrated winding version has a number of advantages, the main of them being the multipolarity. This means that the generator with a concentrated winding can be more acceptable for the direct-drive wind turbines, is easier to make and simpler to operate. Another very important advantage of concentrated windings shown in this work is that they allow achievement of a higher specific electromagnetic torque, which means smaller size and weight of such a generator in the low-speed version.

  16. Concentrations of antibiotics predicted to select for resistant bacteria: Proposed limits for environmental regulation.

    PubMed

    Bengtsson-Palme, Johan; Larsson, D G Joakim

    2016-01-01

    There are concerns that selection pressure from antibiotics in the environment may accelerate the evolution and dissemination of antibiotic-resistant pathogens. Nevertheless, there is currently no regulatory system that takes such risks into account. In part, this is due to limited knowledge of environmental concentrations that might exert selection for resistant bacteria. To experimentally determine minimal selective concentrations in complex microbial ecosystems for all antibiotics would involve considerable effort. In this work, our aim was to estimate upper boundaries for selective concentrations for all common antibiotics, based on the assumption that selective concentrations a priori need to be lower than those completely inhibiting growth. Data on Minimal Inhibitory Concentrations (MICs) were obtained for 111 antibiotics from the public EUCAST database. The 1% lowest observed MICs were identified, and to compensate for limited species coverage, predicted lowest MICs adjusted for the number of tested species were extrapolated through modeling. Predicted No Effect Concentrations (PNECs) for resistance selection were then assessed using an assessment factor of 10 to account for differences between MICs and minimal selective concentrations. The resulting PNECs ranged from 8 ng/L to 64 μg/L. Furthermore, the link between taxonomic similarity between species and lowest MIC was weak. This work provides estimated upper boundaries for selective concentrations (lowest MICs) and PNECs for resistance selection for all common antibiotics. In most cases, PNECs for selection of resistance were below available PNECs for ecotoxicological effects. The generated PNECs can guide implementation of compound-specific emission limits that take into account risks for resistance promotion.

  17. pH- and concentration-programmable electrodialytic buffer generator.

    PubMed

    Chen, Yongjing; Edwards, Brian L; Dasgupta, Purnendu K; Srinivasan, Kannan

    2012-01-01

    We have presented in a companion paper a suppressor-based electrodialytic buffer generator (EBG) that can produce programmable pH gradients. Here we demonstrate a three-electrode EBG. In this three-compartment flow-through device, the central compartment is separated from the outer compartments with a cation-exchange membrane (CEM) and an anion-exchange membrane (AEM), respectively. One platinum electrode is disposed in each compartment. The flows through each compartment are independent. With appropriate solutions in each compartment, independent potentials are applied to the CEM and AEM electrodes with respect to the grounded central electrode. The CEM current and the AEM current can be independently manipulated to generate buffers with variable concentration and pH in the central compartment. Both the CEM and AEM currents can be positive or negative. For the CEM, a positive current (i(cat)(in)) indicates that cations are coming in from the CEM channel to the center. A negative current (i(cat)(out)) takes cations out of the center to the CEM channel. Similarly for the AEM, currents governing anion transport into the center channel from the AEM channel (AEM electrode negative) or the reverse (AEM electrode positive) are respectively denoted by i(an)(in) or i(an)(out). Most examples herein involve inward ion transport, referred to as the additive mode. Depending on whether i(cat)(in) i(an)(in), H(+)/O(2) and OH(-)/H(2) are respectively produced at the central electrode to maintain electroneutrality. Any gas formed is subsequently removed by a gas removal device. The pH of the central channel effluent is related to the ratio of the currents through the two membranes, while the generated concentration is controlled by the absolute value of the currents. The buffer concentration and pH can be varied in a controlled predictable manner. A pH span of 3-12 was attained and a phosphate buffer concentration up to 140 mM was generated. We

  18. Development and validation of a new bitumen fume generation system which generates polycyclic aromatic hydrocarbon concentrations proportional to fume concentrations.

    PubMed

    Binet, S; Bonnet, P; Brandt, H; Castegnaro, M; Delsaut, P; Fabries, J F; Huynh, C K; Lafontaine, M; Morel, G; Nunge, H; Rihn, B; Vu Duc, T; Wrobel, R

    2002-10-01

    Bitumen fumes emitted during road paving and roofing contain polycyclic aromatic compounds (PACs) of potential health concern. Little information is available for an experimental device devoted to inhalation experiments with animals exposed to bitumen fumes, and in all studies the systems were never validated for a range of fume concentrations, which prohibited their use for toxicological concentration-effect studies. Therefore, the purpose of this study was to validate a new experimental device able to generate bitumen fumes at different total particulate matter (TPM) concentrations with a linear correlation between TPM and the concentrations of different PACs, thus allowing toxicological dose-response studies with fumes representative of those in the field. Atmosphere samples collected from an animal exposure chamber allowed the determination of TPM, toluene soluble matter, polycyclic aromatic hydrocarbons (PAHs) and semi-volatiles. The particulate size distributions were determined in order to assess the deposition pattern in the respiratory tract. The temperature of 170 degrees C was chosen by analogy with the upper range of the temperature used during paving operations. The temperature of the air passing over the fume emission area was regulated to 20 degrees C and stirring of the heated bitumen was restricted to 90 r.p.m. The data show that the objective of developing a static fume generation system that reproducibly produces fumes in the inhalation chamber for specified target concentrations (TPM) were successful. The within-day variation coefficients for TPM were between 2.5 and 6.1%. The day-to-day variations for TPM concentration were between 4.1 and 5.8%. The concentrations of the 4-5 ring PAHs and the polycyclic aromatic sulphur heterocycles were proportional to the TPM concentration. The 2 and 3 ring PAH concentrations showed a deviation from proportionality with the TPM, probably due to their re-evaporation during sampling. The mass median aerodynamic

  19. Wavelength-Selective Photovoltaics for Power-generating Greenhouses

    NASA Astrophysics Data System (ADS)

    Carter, Sue; Loik, Michael; Shugar, David; Corrado, Carley; Wade, Catherine; Alers, Glenn

    2014-03-01

    While photovoltaic (PV) technologies are being developed that have the potential for meeting the cost target of 0.50/W per module, the cost of installation combined with the competition over land resources could curtail the wide scale deployment needed to generate the Terrawatts per year required to meet the world's electricity demands. To be cost effective, such large scale power generation will almost certainly require PV solar farms to be installed in agricultural and desert areas, thereby competing with food production, crops for biofuels, or the biodiversity of desert ecosystems. This requirement has put the PV community at odds with both the environmental and agricultural groups they would hope to support through the reduction of greenhouse gas emissions. A possible solution to this challenge is the use of wavelength-selective solar collectors, based on luminescent solar concentrators, that transmit wavelengths needed for plant growth while absorbing the remaining portions of the solar spectrum and converting it to power. Costs are reduced through simultaneous use of land for both food and power production, by replacing the PV cells by inexpensive long-lived luminescent materials as the solar absorber, and by integrating the panels directly into existing greenhouse or cold frames. Results on power generation and crop yields for year-long trials done at academic and commercial greenhouse growers in California will be presented.

  20. Neighborhood Selection and the Social Reproduction of Concentrated Racial Inequality

    PubMed Central

    SAMPSON, ROBERT J.; SHARKEY, PATRICK

    2008-01-01

    In this paper, we consider neighborhood selection as a social process central to the reproduction of racial inequality in neighborhood attainment. We formulate a multilevel model that decomposes multiple sources of stability and change in longitudinal trajectories of achieved neighborhood income among nearly 4,000 Chicago families followed for up to seven years wherever they moved in the United States. Even after we adjust for a comprehensive set of fixed and time-varying covariates, racial inequality in neighborhood attainment is replicated by movers and stayers alike. We also study the emergent consequences of mobility pathways for neighborhood-level structure. The temporal sorting by individuals of different racial and ethnic groups combines to yield a structural pattern of flows between neighborhoods that generates virtually nonoverlapping income distributions and little exchange between minority and white areas. Selection and racially shaped hierarchies are thus mutually constituted and account for an apparent equilibrium of neighborhood inequality. PMID:18390289

  1. Neighborhood selection and the social reproduction of concentrated racial inequality.

    PubMed

    Sampson, Robert J; Sharkey, Patrick

    2008-02-01

    In this paper, we consider neighborhood selection as a social process central to the reproduction of racial inequality in neighborhood attainment. We formulate a multilevel model that decomposes multiple sources of stability and change in longitudinal trajectories of achieved neighborhood income among nearly 4000 Chicago families followed for up to seven years wherever they moved in the United States. Even after we adjust for a comprehensive set of fixed and time-varying covariates, racial inequality in neighborhood attainment is replicated by movers and stayers alike. We also study the emergent consequences of mobility pathways for neighborhood-level structure. The temporal sorting by individuals of different racial and ethnic groups combines to yield a structural pattern offlows between neighborhoods that generates virtually nonoverlapping income distributions and little exchange between minority and white areas. Selection and racially shaped hierarchies are thus mutually constituted and account for an apparent equilibrium of neighborhood inequality.

  2. Concentrations of selected contaminants in cabin air of airbus aircrafts.

    PubMed

    Dechow, M; Sohn, H; Steinhanses, J

    1997-07-01

    The concentrations of selected air quality parameters in aircraft cabins were investigated including particle numbers in cabin air compared to fresh air and recirculation air, the microbiological contamination and the concentration of volatile organic compounds (VOC). The Airbus types A310 of Swissair and A340 of Lufthansa were used for measurements. The particles were found to be mainly emitted by the passengers, especially by smokers. Depending on recirculation filter efficiency the recirculation air contained a lower or equal amount of particles compared to the fresh air, whereas the amount of bacteria exceeded reported concentrations within other indoor spaces. The detected species were mainly non-pathogenic, with droplet infection over short distances identified as the only health risk. The concentration of volatile organic compounds (VOC) were well below threshold values. Ethanol was identified as the compound with the highest amount in cabin air. Further organics were emitted by the passengers--as metabolic products or by smoking--and on ground as engine exhaust (bad airport air quality). Cleaning agents may be the source of further compounds.

  3. Concentration of radionuclides in fresh water fish downstream of Rancho Seco Nuclear Generating Plant

    SciTech Connect

    Noshkin, V.E.; Eagle, R.J.; Dawson, J.M.; Brunk, J.L.; Wong, X.M.

    1984-12-27

    Fish were collected for radionuclide analysis over a 5-month period in 1984 from creeks downstream of the Rancho Seco Nuclear Generating Plant, which has been discharging quantities of some fission and activation products to the waterway since 1981. Among the fish, the bluegill was selected for intensive study because it is very territorial and the radionuclide concentrations detected should be representative of the levels in the local environment at the downstream locations sampled. Among the gamma-emitting radionuclides routinely released, only /sup 134/Cs and /sup 137/Cs were detected in the edible flesh of fish. Concentrations in the flesh of fish decreased with distance from the plant. The relationship between concentration and distance was determined to be exponential. Exponential equations were generated to estimate concentrations in fish at downstream locations where no site-specific information was available. Mean concentrations of /sup 137/Cs in bluegill collected during April, May, July and August from specific downstream stations were not significantly different in spite of the release of 131 mCi to the creeks between April and August. The concentrations in fish are not responding to changes in water concentrations brought about by plant discharges. Diet appears to be a more significant factor than size or weight or water concentration in regulating body burdens of /sup 137/Cs in these fish.

  4. Microfabricated Collector-Generator Electrode Sensor for Measuring Absolute pH and Oxygen Concentrations.

    PubMed

    Dengler, Adam K; Wightman, R Mark; McCarty, Gregory S

    2015-10-20

    Fast-scan cyclic voltammetry (FSCV) has attracted attention for studying in vivo neurotransmission due to its subsecond temporal resolution, selectivity, and sensitivity. Traditional FSCV measurements use background subtraction to isolate changes in the local electrochemical environment, providing detailed information on fluctuations in the concentration of electroactive species. This background subtraction removes information about constant or slowly changing concentrations. However, determination of background concentrations is still important for understanding functioning brain tissue. For example, neural activity is known to consume oxygen and produce carbon dioxide which affects local levels of oxygen and pH. Here, we present a microfabricated microelectrode array which uses FSCV to detect the absolute levels of oxygen and pH in vitro. The sensor is a collector-generator electrode array with carbon microelectrodes spaced 5 μm apart. In this work, a periodic potential step is applied at the generator producing transient local changes in the electrochemical environment. The collector electrode continuously performs FSCV enabling these induced changes in concentration to be recorded with the sensitivity and selectivity of FSCV. A negative potential step applied at the generator produces a transient local pH shift at the collector. The generator-induced pH signal is detected using FSCV at the collector and correlated to absolute solution pH by postcalibration of the anodic peak position. In addition, in oxygenated solutions a negative potential step at the generator produces hydrogen peroxide by reducing oxygen. Hydrogen peroxide is detected with FSCV at the collector electrode, and the magnitude of the oxidative peak is proportional to absolute oxygen concentrations. Oxygen interference on the pH signal is minimal and can be accounted for with a postcalibration.

  5. Selecting tense, aspect, and connecting words in language generation

    SciTech Connect

    Gaasterland, T.; Dorr, B.

    1995-12-31

    Generating language that reflects the temporal organization of represented knowledge requires a language generation model that integrates contemporary theories of tense and aspect, temporal representations, and methods to plan text. This paper presents a model that produces complex sentences that reflect temporal relations present in underlying temporal concepts. The main result of this work is the successful application of constrained linguistic theories of tense and aspect to a generator which produces meaningful event combinations and selects appropriate connecting words that relate them.

  6. Wet-chemistry based selective coatings for concentrating solar power

    NASA Astrophysics Data System (ADS)

    Maimon, Eran; Kribus, Abraham; Flitsanov, Yuri; Shkolnik, Oleg; Feuermann, Daniel; Zwicker, Camille; Larush, Liraz; Mandler, Daniel; Magdassi, Shlomo

    2013-09-01

    Spectrally selective coatings are common in low and medium temperature solar applications from solar water heating collectors to parabolic trough absorber tubes. They are also an essential element for high efficiency in higher temperature Concentrating Solar Power (CSP) systems. Selective coatings for CSP are usually prepared using advanced expensive methods such as sputtering and vapor deposition. In this work, coatings were prepared using low-cost wet-chemistry methods. Solutions based on Alumina and Silica sol gel were prepared and then dispersed with black spinel pigments. The black dispersions were applied by spray/roll coating methods on stainless steel plates. The spectral emissivity of sample coatings was measured in the temperature range between 200 and 500°C, while the spectral absorptivity was measured at room temperature and 500°C. Emissivity at wavelengths of 0.4-1.7 μm was evaluated indirectly using multiple measurements of directional reflectivity. Emissivity at wavelengths 2-14 μm was measured directly using a broadband IR camera that acquires the radiation emitted from the sample, and a range of spectral filters. Emissivity measurement results for a range of coated samples will be presented, and the impact of coating thickness, pigment loading, and surface preparation will be discussed.

  7. Selection Intensity in Genetic Algorithms with Generation Gaps

    SciTech Connect

    Cantu-Paz, E.

    2000-01-19

    This paper presents calculations of the selection intensity of common selection and replacement methods used in genetic algorithms (GAs) with generation gaps. The selection intensity measures the increase of the average fitness of the population after selection, and it can be used to predict the average fitness of the population at each iteration as well as the number of steps until the population converges to a unique solution. In addition, the theory explains the fast convergence of some algorithms with small generation gaps. The accuracy of the calculations was verified experimentally with a simple test function. The results of this study facilitate comparisons between different algorithms, and provide a tool to adjust the selection pressure, which is indispensable to obtain robust algorithms.

  8. Acoustic bubble: Controlled and selective micropropulsion and chemical waveform generator

    NASA Astrophysics Data System (ADS)

    Ahmed, Daniel

    have offered a higher level of sophistication in terms of liquid manipulation, however, due to low Reynolds number associated with these methods, precise temporal manipulation has remained a challenge. Furthermore, varying the sample concentration rapidly and controllably, an important task for a plethora of chemical and biological studies, has proven to be extremely difficult. Here I demonstrate (Chapter 3) a novel approach for generating chemical waveforms that permits continuous modulation of the signal characteristics including the shape, frequency, amplitude (sample concentration), and duty cycle, with frequencies reaching up to 30 Hz. Furthermore, using multiple bubbles of different sizes in a single microchannel, we show fast switching between multiple distinct stimuli, wherein the waveform of each stimulus is independently controlled. Using our device, we characterized the frequency-dependent activation and internalization of the -adrenergic receptor (beta2-AR), a prototypic G-protein coupled receptors (GPCRs) due to epinephrine. We determined that beta2-AR internalization due to epinephrine occurs on timescales between 100 ms and 5sec. The chemical waveform generation and switching method presented herein is expected to be useful for understanding the dynamics of fast biomolecular processes.

  9. Electro-oxidation of reverse osmosis concentrates generated in tertiary water treatment.

    PubMed

    Pérez, G; Fernández-Alba, A R; Urtiaga, A M; Ortiz, I

    2010-05-01

    This work investigates the application of the electro-oxidation technology provided with boron doped diamond (BDD), an electrode material which has shown outstanding properties in oxidation of organic and inorganic compounds, for the treatment of reverse osmosis (RO) concentrates generated in tertiary wastewater treatment plants (WWTP). Chemical oxygen demand (COD), ammonium and several anions were measured during the electro-oxidation process, and the influence of the applied current density (20-200A/m(2)) was analysed on process kinetics. Analytical assessment showed that several emerging pollutants (pharmaceuticals, personal care products, stimulants, etc.) were presented both in the effluent of the secondary WWTP as well as in the RO concentrate. For this reason, a group of 10 emerging pollutants, those found with higher concentrations, was selected in order to test whether electro-oxidation can be also applied for their mitigation. In the removal of emerging pollutants the electrical current density in the range 20-100A/m(2) did not show influence likely due to the mass transfer resistance developed in the process when the oxidized solutes are present in such low concentrations. Their removal rates were fitted to first order expressions, and the apparent kinetic constants for the anodic oxidation of each compound were calculated. Finally, the formation of trihalomethanes (THMs) has been checked; concluding that after selecting the appropriate operational conditions the attained concentration is lower than the standards for drinking water established in European and EPA regulations.

  10. Learning from Chemical Visualizations: Comparing Generation and Selection

    ERIC Educational Resources Information Center

    Zhang, Zhihui Helen; Linn, Marcia C.

    2013-01-01

    Dynamic visualizations can make unseen phenomena such as chemical reactions visible but students need guidance to benefit from them. This study explores the value of generating drawings versus selecting among alternatives to guide students to learn chemical reactions from a dynamic visualization of hydrogen combustion as part of an online inquiry…

  11. Selected classes of minimised hammerhead ribozyme have very high cleavage rates at low Mg2+ concentration.

    PubMed Central

    Conaty, J; Hendry, P; Lockett, T

    1999-01-01

    In vitro selection was used to enrich for highly efficient RNA phosphodiesterases within a size-constrained (18 nt) ribonucleotide domain. The starting population (g0) was directed in trans against an RNA oligonucleotide substrate immobilised to an avidin-magnetic phase. Four rounds of selection were conducted using 20 mM Mg2+to fractionate the population on the basis of divalent metal ion-dependent phosphodiesterase activity. The resulting generation 4 (g4) RNA was then directed through a further two rounds of selection using low concentrations of Mg2+. Generation 6 (g6) was composed of sets of active, trans cleaving minimised ribozymes, containing recognised hammerhead motifs in the conserved nucleotides, but with highly variable linker domains (loop II-L.1-L.4). Cleavage rate constants in the g6 population ranged from 0.004 to 1.3 min-1at 1 mM Mg2+(pH 8.0, 37 degrees C). Selection was further used to define conserved positions between G(10.1) and C(11.1) required for high cleavage activity at low Mg2+concentration. At 10 mM MgCl2the kinetic phenotype of these molecules was comparable to a hammerhead ribozyme with 4 bp in helix II. At low Mg2+concentration, the disparity in cleavage rate constants increases in favour of the minimised ribozymes. Favourable kinetic traits appeared to be a general property for specific selected linker sequences, as the high rates of catalysis were transferable to a different substrate system. PMID:10325431

  12. Prediction of genetic contributions and generation intervals in populations with overlapping generations under selection.

    PubMed Central

    Bijma, P; Woolliams, J A

    1999-01-01

    A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions. PMID:10049935

  13. High-performance flat-panel solar thermoelectric generators with high thermal concentration.

    PubMed

    Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

    2011-05-01

    The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.

  14. High-performance flat-panel solar thermoelectric generators with high thermal concentration.

    PubMed

    Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

    2011-07-01

    The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity. PMID:21532584

  15. A convenient method for positive selection of retroviral producing cells generating vectors devoid of selectable markers.

    PubMed

    Xu, Lai; Tsuji, Kazuhide; Mostowski, Howard; Otsu, Makoto; Candotti, Fabio; Rosenberg, Amy S

    2004-06-01

    Early retroviral vectors containing both a therapeutic gene and a dominant selectable marker gene, offered some distinct advantages with respect to gene therapy, in that they simplified the generation, isolation, and titration of retroviral producer cell clones, as well as the evaluation and selection of successfully targeted cells. However, a number of problems were engendered by this strategy: the promoter driving the selectable marker gene could interfere with transcription of the therapeutic gene, and immune responses could be induced to cells expressing foreign proteins of selection marker origin. Simplified retroviral vectors, which lack a selection marker gene, were constructed to address these problems, but the inability to use a selection marker has made identification and cloning of virus producing transfected cells a heavy burden. To maintain the benefits of simplified retroviral vectors, while providing a facile means to select packaging cells transfected with retroviral DNA, we cloned the bacterial selection marker gene encoding neomycin phosphotransferase (neo) into the plasmid backbone of the vector, but outside of the provirus, resulting in efficient selection of transfected packaging cells and generation of packaged virus which lacks the neo gene. This novel approach generates greater numbers of high infectious titer producing clones, after selection in G418 media, than does a co-transfection approach, due to integration of higher construct copy numbers per cell. No transmission of the selection marker gene to target cells was observed following retroviral transduction. Thus, our strategy eliminates the adverse consequences of a selection-based method, while diminishing the burden of identification of packaging cells transfected with vectors devoid of selectable markers.

  16. Metal concentrations and distribution in paint waste generated during bridge rehabilitation in New York State.

    PubMed

    Shu, Zhan; Axe, Lisa; Jahan, Kauser; Ramanujachary, Kandalam V; Kochersberger, Carl

    2015-09-01

    Between 1950 and 1980, lead and chromium along with other metals have been used in paint coatings to protect bridges from corrosion. In New York State with 4500 bridges in 11 Regions 2385 of the bridges have been rehabilitated and subsequently repainted after 1989 when commercial use of lead based paint was prohibited. The purpose of this research was to address the concentration and distribution of trace metals in the paint waste generated during bridge rehabilitation. Using hypothesis testing and stratified sampling theory, a representative sample size of 24 bridges from across the state was selected that resulted in 117 paint waste samples. Field portable X-ray fluorescence (FP-XRF) analysis revealed metal concentrations ranged from 5 to 168,090 mg kg(-1) for Pb, 49,367 to 799,210 mg kg(-1) for Fe, and 27 to 425,510 mg kg(-1) for Zn. Eighty percent of the samples exhibited lead concentrations greater than 5000 mg kg(-1). The elevated iron concentrations may be attributed to the application of steel grit as an abrasive blasting material routinely used by state Departments of Transportation in the paint removal process. Other metals including Ba and Cr were observed in the paint waste as well. As a result of the paint formulation, metals were found to be associated in the paint waste (Pb correlated with Cr (r=0.85)). The elevated metal concentrations observed raises concern over the potential impact of leaching from this waste stream.

  17. Pharmacokinetics and tissue concentrations of tylosin in selected avian species

    USGS Publications Warehouse

    Locke, D.; Bush, M.; Carpenter, J.W.

    1982-01-01

    Tissue and plasma concentrations and the biological half-life of tylosin in avian species of a variety of body sizes and metabolic rates were studied. The species chosen were eastern bobwhite quail (Colinus virginianus virginianus), pigeons (Columba livia), greater sandhill cranes (Grus canadensis tabida), and emus (Dromaius novaehollandiae). In the 1st phase of this study, tylosin was administered IM to quail, pigeons, and emus at a dosage rate of 25 mg/kg of body weight and to cranes at a dosage rate of 15 mg/kg. The average peak plasma concentrations of tylosin in quail, pigeons, cranes, and emus were 4.31, 5.63, 3.62, and 3.26 microgram/ml, respectively. These peak concentrations occurred at 0.5 to 1.5 hours after administration. The biological half-life of tylosin averaged 1.2 hours in quail, pigeons, and cranes, and was 4.7 hours in emus. In the 2nd phase of this study, tylosin concentrations in the tissues of quail, pigeons, and cranes were markedly higher than were plasma concentrations at corresponding sampling times. Six hours after antibiotic administration, tissue concentrations of tylosin in all species remained within the minimum inhibitory concentration for most pathogenic organisms. Dosage regimens of 25 mg of tylosin/kg 4 times daily for quail and pigeons, 15 mg/kg 3 times daily for cranes, and 25 mg/kg 3 times daily for emus would be needed to establish and maintain therapeutic tissue concentrations.

  18. Prediction of cadmium concentration in selected home-produced vegetables.

    PubMed

    Bešter, Petra Karo; Lobnik, Franc; Eržen, Ivan; Kastelec, Damijana; Zupan, Marko

    2013-10-01

    Soil contaminated with cadmium presents a potential hazard for humans, animals and plants. The latter play a major role in the transfer of cadmium to the food chain. The uptake of cadmium and its accumulation by plants is dependent on various soil, plants and environmental factors. In order to identify soil properties with statistically significant influence on cadmium concentration in vegetables and to reduce the collection of data, time and costs, regression models can be applied. The main objective of this research was to develop regression models to predict the concentration of cadmium in 9-vegetable species: zucchini, tomato, cabbage, onion, potato, carrot, red beet, endive and chicory, based on soil properties. Soil samples were collected from 123 home gardens of the Municipality of Celje and 59 of these gardens were also included in vegetable sampling. The concentration of elements (e.g. arsenic, cadmium, copper, lead, and zinc) in the samples was determined by Inductively Coupled Plasma Mass Spectrometry. Single (for cabbage, potato, red beet and chicory) and multiple (for tomato, onion, carrot and endive) linear regression models were developed. There was no statistically significant regression model for zucchini. The most significant parameter for the influencing the cadmium concentration in vegetables was the concentration of cadmium in soil. Other important soil properties were the content of organic matter, pH-value and the concentration of manganese. It was concluded that consuming carrots, red beets, endives, onions, potatoes and chicory which are grown in gardens with Cd concentrations (mgkg(-1) DW) above 2.4, 3.2, 6.3, 7.9, 8.3 and 10.9, respectively, might represent an important contribution to dietary Cd exposure. PMID:23886800

  19. NMR analysis of weak molecular interactions using slice-selective experiments via study of concentration gradients in agar gels.

    PubMed

    Mitrev, Y; Simova, S; Jeannerat, D

    2016-04-01

    Weak molecular interactions can be localized and quantified using a single NMR experiment analysing concentration gradients generated in agar gels. The spectra from various cross-sections along the gradient were obtained using a slice-selective pulse sequence realisable with standard NMR equipment.

  20. Spacecraft maximum allowable concentrations for selected airborne contaminants, volume 1

    NASA Technical Reports Server (NTRS)

    1994-01-01

    As part of its efforts to promote safe conditions aboard spacecraft, NASA requested the National Research Council (NRC) to develop guidelines for establishing spacecraft maximum allowable concentrations (SMAC's) for contaminants, and to review SMAC's for various spacecraft contaminants to determine whether NASA's recommended exposure limits are consistent with the guidelines recommended by the subcommittee. In response to NASA's request, the NRC organized the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants within the Committee on Toxicology (COT). In the first phase of its work, the subcommittee developed the criteria and methods for preparing SMAC's for spacecraft contaminants. The subcommittee's report, entitled Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants, was published in 1992. The executive summary of that report is reprinted as Appendix A of this volume. In the second phase of the study, the Subcommittee on Spacecraft Maximum Allowable Concentrations reviewed reports prepared by NASA scientists and contractors recommending SMAC's for 35 spacecraft contaminants. The subcommittee sought to determine whether the SMAC reports were consistent with the 1992 guidelines. Appendix B of this volume contains the first 11 SMAC reports that have been reviewed for their application of the guidelines developed in the first phase of this activity and approved by the subcommittee.

  1. Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants. Volume 2

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The National Aeronautics and Space Administration (NASA) is aware of the potential toxicological hazards to humans that might be associated with prolonged spacecraft missions. Despite major engineering advances in controlling the atmosphere within spacecraft, some contamination of the air appears inevitable. NASA has measured numerous airborne contaminants during space missions. As the missions increase in duration and complexity, ensuring the health and well-being of astronauts traveling and working in this unique environment becomes increasingly difficult. As part of its efforts to promote safe conditions aboard spacecraft, NASA requested the National Research Council (NRC) to develop guidelines for establishing spacecraft maximum allowable concentrations (SMACs) for contaminants, and to review SMACs for various space-craft contaminants to determine whether NASA's recommended exposure limits are consistent with the guidelines recommended by the subcommittee. In response to NASA's request, the NRC organized the Subcommittee on Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants within the Committee On Toxicology (COT). In the first phase of its work, the subcommittee developed the criteria and methods for preparing SMACs for spacecraft contaminants. The subcommittee's report, entitled Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants, was published in 1992. The executive summary of that report is reprinted as Appendix A of this volume. In the second phase of the study, the Subcommittee on Spacecraft Maximum Allowable Concentrations reviewed reports prepared by NASA scientists and contractors recommending SMACs for approximately 35 spacecraft contaminants. The subcommittee sought to determine whether the SMAC reports were consistent with the 1992 guidelines. Appendix B of this volume contains the SMAC reports for 12 chemical contaminants that have been reviewed for

  2. Magnetic flux concentrations from dynamo-generated fields

    NASA Astrophysics Data System (ADS)

    Jabbari, S.; Brandenburg, A.; Losada, I. R.; Kleeorin, N.; Rogachevskii, I.

    2014-08-01

    Context. The mean-field theory of magnetized stellar convection gives rise to two distinct instabilities: the large-scale dynamo instability, operating in the bulk of the convection zone and a negative effective magnetic pressure instability (NEMPI) operating in the strongly stratified surface layers. The latter might be important in connection with magnetic spot formation. However, as follows from theoretical analysis, the growth rate of NEMPI is suppressed with increasing rotation rates. On the other hand, recent direct numerical simulations (DNS) have shown a subsequent increase in the growth rate. Aims: We examine quantitatively whether this increase in the growth rate of NEMPI can be explained by an α2 mean-field dynamo, and whether both NEMPI and the dynamo instability can operate at the same time. Methods: We use both DNS and mean-field simulations (MFS) to solve the underlying equations numerically either with or without an imposed horizontal field. We use the test-field method to compute relevant dynamo coefficients. Results: DNS show that magnetic flux concentrations are still possible up to rotation rates above which the large-scale dynamo effect produces mean magnetic fields. The resulting DNS growth rates are quantitatively reproduced with MFS. As expected for weak or vanishing rotation, the growth rate of NEMPI increases with increasing gravity, but there is a correction term for strong gravity and large turbulent magnetic diffusivity. Conclusions: Magnetic flux concentrations are still possible for rotation rates above which dynamo action takes over. For the solar rotation rate, the corresponding turbulent turnover time is about 5 h, with dynamo action commencing in the layers beneath.

  3. Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants. Volume 5

    NASA Technical Reports Server (NTRS)

    2008-01-01

    To protect space crews from air contaminants, NASA requested that the National Research Council (NRC) provide guidance for developing spacecraft maximum allowable concentrations (SMACs) and review NASA's development of exposure guidelines for specific chemicals. The NRC convened the Committee on Spacecraft Exposure Guidelines to address this task. The committee published Guidelines for Developing Spacecraft Maximum Allowable Concentrations for Space Station Contaminants (NRC 1992). The reason for the review of chemicals in Volume 5 is that many of them have not been examined for more than 10 years, and new research necessitates examining the documents to ensure that they reflect current knowledge. New knowledge can be in the form of toxicologic data or in the application of new approaches for analysis of available data. In addition, because NASA anticipates longer space missions beyond low Earth orbit, SMACs for 1,000-d exposures have also been developed.

  4. Development of second generation EP2 antagonists with high selectivity

    PubMed Central

    Ganesh, Thota; Jiang, Jianxiong; Dingledine, Ray

    2014-01-01

    EP2 receptor has emerged as an important biological target for therapeutic intervention. In particular, it has been shown to exacerbate disease progression of a variety of CNS and peripheral diseases. Deletion of the EP2 receptor in mouse models recapitulates several features of the COX-2 inhibition, thus presenting a new avenue for anti-inflammatory therapy which could bypass some of the adverse side effects observed by the COX-2 inhibition therapy. We have recently reported a cinnamic amide class of EP2 antagonists with high potency, but these compounds exhibited a moderate selectivity against prostanoid receptor DP1. Moreover they possess acrylamide moiety in the structure, which may result in liver toxicity over longer period of use in a chronic disease model. Thus, we now developed a second generation compounds that devoid of the acrylamide functionality and possess high potency and improved (>1000-fold) selectivity to EP2 over other prostanoid receptors. PMID:24937185

  5. Generation and Selection of Orf Virus (ORFV) Recombinants.

    PubMed

    Rziha, Hanns-Joachim; Rohde, Jörg; Amann, Ralf

    2016-01-01

    Orf virus (ORFV) is an epitheliotropic poxvirus, which belongs to the genus Parapoxvirus. Among them the highly attenuated, apathogenic strain D1701-V is regarded as a promising candidate for novel virus vector vaccines. Our recent work demonstrated that those ORFV-based recombinants were able to induce protective, long-lasting immunity in various hosts that are non-permissive for ORFV. In this chapter we describe procedures for the generation, selection, propagation, and titration of ORFV recombinants as well as transgene detection by PCR or immunohistochemical staining.

  6. Next Generation Nuclear Plant Materials Selection and Qualification Program Plan

    SciTech Connect

    R. Doug Hamelin; G. O. Hayner

    2004-11-01

    The U.S. Department of Energy (DOE) has selected the Very High Temperature Reactor (VHTR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production without greenhouse gas emissions. The reactor design is a graphite-moderated, helium-cooled, prismatic or pebble bed thermal neutron spectrum reactor with an average reactor outlet temperature of at least 1000 C. The NGNP will use very high burn up, lowenriched uranium, TRISO-Coated fuel in a once-through fuel cycle. The design service life of the NGNP is 60 years.

  7. Selenium concentrations of selected medicinal and aromatic plants in Turkey.

    PubMed

    Ozkutlu, Faruk; Sekeroglu, Nazim; Koca, Ufuk; Yazici, Gizem

    2011-10-01

    Recent scientific studies have proven the importance of trace elements on human health. The main food supplies are plants and animals, which are significant sources of these minerals. Studies on determining mineral compositions of herbs, spices and some other crops have increased all over the world. Published works revealed that spices, herbs and medicinal plants should be consumed to obtain beneficial trace elements. Selenium (Se), one of the most vital trace elements, has a significant role in human diet acting as a preventative agent against some serious illnesses. Despite numerous scientific works on mineral compositions of medicinal and aromatic plants, investigations of selenium content in these foods could not be successfully studied until recently due to the lack of suitable analytical methods for selenium analysis. Thus, publications on selenium concentrations of foods are recent. In this regard, selenium contents of some medicinal and aromatic plants commonly used as spices, herbal teas and traditional medicines in Turkey were studied in the present research. Selenium contents of the most used parts of these plants were analyzed by ICP-OES (Varian Vista-Pro, Australia). Of the analyzed 26 medicinal and aromatic plants, the highest Se concentration (1133 microg kg-1) was found in sweet basil (Ocimum basilicum L.) and the lowest in sumac (Rhus coriaria L.) fruits (11 microg kg(-1)). PMID:22164785

  8. Concentration of strontium-90 at selected hot spots in Japan.

    PubMed

    Steinhauser, Georg; Schauer, Viktoria; Shozugawa, Katsumi

    2013-01-01

    This study is dedicated to the environmental monitoring of radionuclides released in the course of the Fukushima nuclear accident. The activity concentrations of β(-)-emitting (90)Sr and β(-)/γ-emitting (134)Cs and (137)Cs from several hot spots in Japan were determined in soil and vegetation samples. The (90)Sr contamination levels of the samples were relatively low and did not exceed the Bq⋅g(-1) range. They were up four orders of magnitude lower than the respective (137)Cs levels. This study, therefore, experimentally confirms previous predictions indicating a low release of (90)Sr from the Fukushima reactors, due to its low volatility. The radiocesium contamination could be clearly attributed to the Fukushima nuclear accident via its activity ratio fingerprint ((134)Cs/(137)Cs). Although the correlation between (90)Sr and (137)Cs is relatively weak, the data set suggests an intrinsic coexistence of both radionuclides in the contaminations caused by the Fukushima nuclear accident. This observation is of great importance not only for remediation campaigns but also for the current food monitoring campaigns, which currently rely on the assumption that the activity concentrations of β(-)-emitting (90)Sr (which is relatively laborious to determine) is not higher than 10% of the level of γ-emitting (137)Cs (which can be measured quickly). This assumption could be confirmed for the samples investigated herein.

  9. Concentration of Strontium-90 at Selected Hot Spots in Japan

    PubMed Central

    Steinhauser, Georg; Schauer, Viktoria; Shozugawa, Katsumi

    2013-01-01

    This study is dedicated to the environmental monitoring of radionuclides released in the course of the Fukushima nuclear accident. The activity concentrations of β− -emitting 90Sr and β−/γ-emitting 134Cs and 137Cs from several hot spots in Japan were determined in soil and vegetation samples. The 90Sr contamination levels of the samples were relatively low and did not exceed the Bq⋅g−1 range. They were up four orders of magnitude lower than the respective 137Cs levels. This study, therefore, experimentally confirms previous predictions indicating a low release of 90Sr from the Fukushima reactors, due to its low volatility. The radiocesium contamination could be clearly attributed to the Fukushima nuclear accident via its activity ratio fingerprint (134Cs/137Cs). Although the correlation between 90Sr and 137Cs is relatively weak, the data set suggests an intrinsic coexistence of both radionuclides in the contaminations caused by the Fukushima nuclear accident. This observation is of great importance not only for remediation campaigns but also for the current food monitoring campaigns, which currently rely on the assumption that the activity concentrations of β−-emitting 90Sr (which is relatively laborious to determine) is not higher than 10% of the level of γ-emitting 137Cs (which can be measured quickly). This assumption could be confirmed for the samples investigated herein. PMID:23505440

  10. Enhanced diffusion weighting generated by selective adiabatic pulse trains

    NASA Astrophysics Data System (ADS)

    Sun, Ziqi; Bartha, Robert

    2007-09-01

    A theoretical description and experimental validation of the enhanced diffusion weighting generated by selective adiabatic full passage (AFP) pulse trains is provided. Six phantoms (Ph-1-Ph-6) were studied on a 4 T Varian/Siemens whole body MRI system. Phantoms consisted of 2.8 cm diameter plastic tubes containing a mixture of 10 μm ORGASOL polymer beads and 2 mM Gd-DTPA dissolved in 5% agar (Ph-1) or nickel(II) ammonium sulphate hexahydrate doped (56.3-0.8 mM) water solutions (Ph-2-Ph-6). A customized localization by adiabatic selective refocusing (LASER) sequence containing slice selective AFP pulse trains and pulsed diffusion gradients applied in the phase encoding direction was used to measure 1H 2O diffusion. The b-value associated with the LASER sequence was derived using the Bloch-Torrey equation. The apparent diffusion coefficients measured by LASER were comparable to those measured by a conventional pulsed gradient spin-echo (PGSE) sequence for all phantoms. Image signal intensity increased in Ph-1 and decreased in Ph-2-Ph-6 as AFP pulse train length increased while maintaining a constant echo-time. These experimental results suggest that such AFP pulse trains can enhance contrast between regions containing microscopic magnetic susceptibility variations and homogeneous regions in which dynamic dephasing relaxation mechanisms are dominant.

  11. Selection of materials for sodium fast reactor steam generators

    SciTech Connect

    Dubiez-Le Goff, S.; Garnier, S.; Gelineau, O.; Dalle, F.; Blat-Yrieix, M.; Augem, J. M.

    2012-07-01

    Sodium Fast Reactor (SFR) is considered in France as the most mature technology of the different Generation IV systems. In the short-term the designing work is focused on the identification of the potential tracks to demonstrate licensing capability, availability, in-service inspection capability and economical performance. In that frame materials selection for the major components, as the steam generator, is a particularly key point managed within a French Research and Development program launched by AREVA, CEA and EDF. The choice of the material for the steam generator is indeed complex because various aspects shall be considered like mechanical and thermal properties at high temperature, interaction with sodium on one side and water and steam on the other side, resistance to wastage, procurement, fabrication, weldability and ability for inspection and in-situ intervention. The following relevant options are evaluated: the modified 9Cr1Mo ferritic-martensitic grade and the Alloy 800 austenitic grade. The objective of this paper is to assess for both candidates their abilities to reach the current SFR needs regarding material design data, from AFCEN RCC-MRx Code in particular, compatibility with environments and manufacturability. (authors)

  12. Optical design of wavelength selective CPVT system with 3D/2D hybrid concentration

    NASA Astrophysics Data System (ADS)

    Ahmad, N.; Ijiro, T.; Yamada, N.; Kawaguchi, T.; Maemura, T.; Ohashi, H.

    2012-10-01

    Optical design of a concentrating photovoltaic/thermal (CPVT) system is carried out. Using wavelength-selective optics, the system demonstrates 3-D concentration onto a solar cell and 2-D concentration onto a thermal receiver. Characteristics of the two types of concentrator systems are examined with ray-tracing analysis. The first system is a glazed mirror-based concentrator system mounted on a 2-axis pedestal tracker. The size of the secondary optical element is minimized to decrease the cost of the system, and it has a wavelength-selective function for performing 3-D concentration onto a solar cell and 2-D concentration onto a thermal receiver. The second system is a non-glazed beamdown concentrator system containing parabolic mirrors in the lower part. The beam-down selective mirror performs 3-D concentration onto a solar cell placed above the beam-down selective mirror, and 2-D concentration down to a thermal receiver placed at the bottom level. The system is mounted on a two-axis carousel tracker. A parametric study is performed for those systems with different geometrical 2-D/3-D concentration ratios. Wavelength-selective optics such as hot/cold mirrors and spectrum-splitting technologies are taken into account in the analysis. Results show reduced heat load on the solar cell and increased total system efficiency compared to a non-selective CPV system. Requirements for the wavelength-selective properties are elucidated. It is also shown that the hybrid concept with 2-D concentration onto a thermal receiver and 3-D concentration onto a solar cell has an advantageous geometry because of the high total system efficiency and compatibility with the piping arrangement of the thermal receiver.

  13. Trial maneuver generation and selection in the Paladin tactical decision generation system

    NASA Technical Reports Server (NTRS)

    Chappell, Alan R.; Mcmanus, John W.; Goodrich, Kenneth H.

    1993-01-01

    To date, increased levels of maneuverability and controllability in aircraft have been postulated as tactically advantageous, but little research has studied maneuvers or tactics that make use of these capabilities. In order to help fill this void, a real-time tactical decision generation system for air combat engagements, Paladin, has been developed. Paladin models an air combat engagement as a series of discrete decisions. A detailed description of Paladin's decision making process is presented. This includes the sources of data used, methods of generating reasonable maneuvers for the Paladin aircraft, and selection criteria for choosing the 'best' maneuver. Simulation results are presented that show Paladin to be relatively insensitive to errors introduced into the decision process by estimation of future positional and geometric data.

  14. Trial Maneuver Generation and Selection in the Paladin Tactical Decision Generation System

    NASA Technical Reports Server (NTRS)

    Chappell, Alan R.; McManus, John W.; Goodrich, Kenneth H.

    1992-01-01

    To date, increased levels of maneuverability and controllability in aircraft have been postulated as tactically advantageous, but little research has studied maneuvers or tactics that make use of these capabilities. In order to help fill this void, a real time tactical decision generation system for air combat engagements, Paladin, has been developed. Paladin models an air combat engagement as a series of discrete decisions. A detailed description of Paladin's decision making process is presented. This includes the sources of data used, methods of generating reasonable maneuvers for the Paladin aircraft, and selection criteria for choosing the "best" maneuver. Simulation results are presented that show Paladin to be relatively insensitive to errors introduced into the decision process by estimation of future positional and geometric data.

  15. Informing Selection of Nanomaterial Concentrations for ToxCast In Vitro Testing based on Occupational Exposure Potential

    EPA Science Inventory

    Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable. We reviewed published ENM concentr...

  16. High Temperature Irradiation Effects in Selected Generation IV Structural Alloys

    SciTech Connect

    Nanstad, Randy K; McClintock, David A; Hoelzer, David T; Tan, Lizhen; Allen, Todd R.

    2009-01-01

    In the Generation IV Materials Program cross-cutting task, irradiation and testing were carried out to address the issue of high temperature irradiation effects with selected current and potential candidate metallic alloys. The materials tested were (1) a high-nickel iron-base alloy (Alloy 800H); (2) a nickel-base alloy (Alloy 617); (3) two advanced nano-structured ferritic alloys (designated 14YWT and 14WT); and (4) a commercial ferritic-martensitic steel (annealed 9Cr-1MoV). Small tensile specimens were irradiated in rabbit capsules in the High-Flux Isotope Reactor at temperatures from about 550 to 700 C and to irradiation doses in the range 1.2 to 1.6 dpa. The Alloy 800H and Alloy 617 exhibited significant hardening after irradiation at 580 C; some hardening occurred at 660 C as well, but the 800H showed extremely low tensile elongations when tested at 700 C. Notably, the grain boundary engineered 800H exhibited even greater hardening at 580 C and retained a high amount of ductility. Irradiation effects on the two nano-structured ferritic alloys and the annealed 9Cr-1MoV were relatively slight at this low dose.

  17. Steam generation under one sun enabled by a floating structure with thermal concentration

    NASA Astrophysics Data System (ADS)

    Ni, George; Li, Gabriel; Boriskina, Svetlana V.; Li, Hongxia; Yang, Weilin; Zhang, Tiejun; Chen, Gang

    2016-09-01

    Harvesting solar energy as heat has many applications, such as power generation, residential water heating, desalination, distillation and wastewater treatment. However, the solar flux is diffuse, and often requires optical concentration, a costly component, to generate the high temperatures needed for some of these applications. Here we demonstrate a floating solar receiver capable of generating 100 ∘C steam under ambient air conditions without optical concentration. The high temperatures are achieved by using thermal concentration and heat localization, which reduce the convective, conductive and radiative heat losses. This demonstration of a low-cost and scalable solar vapour generator holds the promise of significantly expanding the application domain and reducing the cost of solar thermal systems.

  18. Steam generation under one sun enabled by a floating structure with thermal concentration

    NASA Astrophysics Data System (ADS)

    Ni, George; Li, Gabriel; Boriskina, Svetlana V.; Li, Hongxia; Yang, Weilin; Zhang, Tiejun; Chen, Gang

    2016-09-01

    Harvesting solar energy as heat has many applications, such as power generation, residential water heating, desalination, distillation and wastewater treatment. However, the solar flux is diffuse, and often requires optical concentration, a costly component, to generate the high temperatures needed for some of these applications. Here we demonstrate a floating solar receiver capable of generating 100 ∘C steam under ambient air conditions without optical concentration. The high temperatures are achieved by using thermal concentration and heat localization, which reduce the convective, conductive and radiative heat losses. This demonstration of a low-cost and scalable solar vapour generator holds the promise of significantly expanding the application domain and reducing the cost of solar thermal systems.

  19. Comparative study on the selective chalcopyrite bioleaching of a molybdenite concentrate with mesophilic and thermophilic bacteria.

    PubMed

    Romano, P; Blázquez, M L; Alguacil, F J; Muñoz, J A; Ballester, A; González, F

    2001-03-01

    This study evaluates different bioleaching treatments of a molybdenite concentrate using mesophilic and thermophilic bacterial cultures. Further studies on the chemical leaching and the electrochemical behavior of the MoS(2) concentrate were carried out. Bioleaching tests showed a progressive removal of chalcopyrite from the molybdenite concentrate with an increase in temperature. Chemical leaching tests support the idea of an indirect attack of the concentrate. Electrochemical tests indicate that chalcopyrite dissolution is favored when molybdenite is present. Therefore, this type of bioleaching treatment could be applied to purify molybdenite flotation concentrates by selectively dissolving chalcopyrite. PMID:11257551

  20. Highly Localized Acoustic Streaming and Size-Selective Submicrometer Particle Concentration Using High Frequency Microscale Focused Acoustic Fields.

    PubMed

    Collins, David J; Ma, Zhichao; Ai, Ye

    2016-05-17

    Concentration and separation of particles and biological specimens are fundamental functions of micro/nanofluidic systems. Acoustic streaming is an effective and biocompatible way to create rapid microscale fluid motion and induce particle capture, though the >100 MHz frequencies required to directly generate acoustic body forces on the microscale have traditionally been difficult to generate and localize in a way that is amenable to efficient generation of streaming. Moreover, acoustic, hydrodynamic, and electrical forces as typically applied have difficulty manipulating specimens in the submicrometer regime. In this work, we introduce highly focused traveling surface acoustic waves (SAW) at high frequencies between 193 and 636 MHz for efficient and highly localized production of acoustic streaming vortices on microfluidic length scales. Concentration occurs via a novel mechanism, whereby the combined acoustic radiation and streaming field results in size-selective aggregation in fluid streamlines in the vicinity of a high-amplitude acoustic beam, as opposed to previous acoustic radiation induced particle concentration where objects typically migrate toward minimum pressure locations. Though the acoustic streaming is induced by a traveling wave, we are able to manipulate particles an order of magnitude smaller than possible using the traveling wave force alone. We experimentally and theoretically examine the range of particle sizes that can be captured in fluid streamlines using this technique, with rapid particle concentration demonstrated down to 300 nm diameters. We also demonstrate that locations of trapping and concentration are size-dependent, which is attributed to the combined effects of the acoustic streaming and acoustic forces.

  1. Wet oxidation process concentration of iron and copper steam generator cleaning solvents

    SciTech Connect

    Baldwin, P.N. Jr.; Nakashima, T.

    1995-11-01

    The use of ethylene diamine tetraacetic acid (EDTA) metal cleaning formulations is broadly based. Usually the form of the EDTA used is the tetra ammonium salt. These formulations were developed by the power industry for specific use in maintaining steam generators. When these powerful cleaning solutions are used, they attract not only the key metals of interest, iron and copper, but also can and do remove small levels of other available metals such as chrome. A reduction in the volume of these cleaners is required in order to meet waste management and disposal standards. This paper deals with one method of volume reduction, concentration through evaporation. Once volume reduced, the waste can then be further treated through the use of Wet Oxidation. The effect of this process on the Total Organic Carbon (TOC) contained in the copper as well as the iron spent cleaning solutions is reviewed, including regression analysis of selected data. A regressive comparison is made between the EDTA and the TOC analyzed in the Wet Oxidation batch residuals.

  2. Serum Concentrations of Selected Persistent Organic Pollutants in a Sample of Pregnant Females and Changes in Their Concentrations during Gestation

    PubMed Central

    Wang, Richard Y.; Jain, Ram B.; Wolkin, Amy F.; Rubin, Carol H.; Needham, Larry L.

    2009-01-01

    Objectives In this study we evaluated the concentrations of selected persistent organic pollutants in a sample of first-time pregnant females residing in the United States and assessed differences in these concentrations in all pregnant females during gestation. Methods We reviewed demographic and laboratory data for pregnant females participating in the National Health and Nutrition Examination Survey, including concentrations of 25 polychlorinated biphenyls (PCBs), 6 polychlorinated dibenzo-p-dioxins (PCDDs), 9 polychlorinated dibenzofurans (PCDFs), and 9 organochlorine pesticides. We report serum concentrations for first-time pregnant females (2001–2002; n = 49) and evaluate these concentrations in all pregnant females by trimester (1999–2002; n = 203) using a cross-sectional analysis. Results The chemicals with ≥ 60% detection included PCBs (congeners 126, 138/158, 153, 180), PCDDs/PCDFs [1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (1234678HpCDD), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (123678HxCDD), 1,2,3,4,6,7,8-heptachlorodibenzofuran (1234678HpCDF), 1,1′-(2,2-dichloroethenylidene)-bis(4-chlorobenzene) (p,p′-DDE)], and trans-nonachlor. The geometric mean concentration (95% confidence intervals) for 1234678HpCDD was 15.9 pg/g lipid (5.0–50.6 pg/g); for 123678HxCDD, 9.7 pg/g (5.5–17.1 pg/g); and for 1234678HpCDF, 5.4 pg/g (3.3–8.7 pg/g). The differences in concentrations of these chemicals by trimester were better accounted for with the use of lipid-adjusted units than with whole-weight units; however, the increase in the third-trimester concentration was greater for PCDDs/PCDFs (123678HxCDD, 1234678HpCDF) than for the highest concentration of indicator PCBs (138/158, 153, 180), even after adjusting for potential confounders. Conclusion The concentrations of these persistent organic pollutants in a sample of first-time pregnant females living in the United States suggest a decline in exposures to these chemicals since their ban or restricted use

  3. [Continuous Generation of Hydrogen Peroxide in Water Containing Very Low Concentrations of Unsymmetrical Dimethylhydrazine].

    PubMed

    Bruskov, V I; Yaguzhinsky, L S; Masalimov, Z K; Chernikov, A V; Emelyanenko, V I; Gudkov, S V

    2015-01-01

    Continuous generation of hydrogen peroxide catalyzed by low concentrations of 1,1-dimethylhydrazine (heptyl)--a rocket fuel component--in air saturated water was shown by the method of enhanced chemiluminescence in the system of luminol-p-iodophenol-peroxidase. The concentration dependence and the influence of heat and light on the formation of hydrogen peroxide in the water under the influence of dimethylhydrazine at concentrations considerably lower than maximum allowable concentrations were studied, and the physical-chemical mechanism of this process was considered. It is supposed that dimethylhydrazine at ultra-low concentrations is associated with air nanobubbles and represents a long-lived complex performing catalysis of hydrogen peroxide formation under the influence of heat and light. We put forward the new concept of.toxicity of dimethylhydrazine at very low concentrations due to violation of homeostasis of reactive oxygen species formation in aqueous solutions entering the body of humans and animals.

  4. Multi-generational effects of propranolol on Daphnia magna at different environmental concentrations.

    PubMed

    Jeong, Tae-Yong; Kim, Hyun Young; Kim, Sang Don

    2015-11-01

    To evaluate the effects of propranolol on Daphnia magna (D. magna), we employed a multi-generational exposure period for eight generations and an environmentally relevant low concentration with 1.5 ng/L, 0.2 μg/L and 26 μg/L to reflect a realistic exposure scenario. Physiological endpoints were checked, including growth, number of neonates, heart rate, frequency of abdominal appendage movement and malformation rate of neonates. In the results, growth and abdominal appendage movement were affected by environmental concentration during several generations, and the responses showed consistent tendencies of response increase with concentration increase. Heart rate was the only endpoint affected throughout all exposure generations. Inhibitory and acceleratory effects on heart rate, growth and abdominal appendage movement suggest that it is necessary to cover sub-lethal endpoints of non-targeted organisms in eco-toxicity study because the physiological responses were detected at much lower concentrations than the results of traditional toxicity tests, including environmental concentration.

  5. Novel selective inhibitors of aminopeptidases that generate antigenic peptides.

    PubMed

    Papakyriakou, Athanasios; Zervoudi, Efthalia; Theodorakis, Emmanuel A; Saveanu, Loredana; Stratikos, Efstratios; Vourloumis, Dionisios

    2013-09-01

    Endoplasmic reticulum aminopeptidases, ERAP1 and ERAP2, as well as Insulin regulated aminopeptidase (IRAP) play key roles in antigen processing, and have recently emerged as biologically important targets for manipulation of antigen presentation. Taking advantage of the available structural and substrate-selectivity data for these enzymes, we have rationally designed a new series of inhibitors that display low micromolar activity. The selectivity profile for these three highly homologous aminopeptidases provides a promising avenue for modulating intracellular antigen processing.

  6. Catalytic conversion reactions in nanoporous systems with concentration-dependent selectivity: Statistical mechanical modeling

    DOE PAGES

    Garcia, Andres; Wang, Jing; Windus, Theresa L.; Sadow, Aaron D.; Evans, James W.

    2016-05-20

    Statistical mechanical modeling is developed to describe a catalytic conversion reaction A → Bc or Bt with concentration-dependent selectivity of the products, Bc or Bt, where reaction occurs inside catalytic particles traversed by narrow linear nanopores. The associated restricted diffusive transport, which in the extreme case is described by single-file diffusion, naturally induces strong concentration gradients. Hence, by comparing kinetic Monte Carlo simulation results with analytic treatments, selectivity is shown to be impacted by strong spatial correlations induced by restricted diffusivity in the presence of reaction and also by a subtle clustering of reactants, A.

  7. Catalytic conversion reactions in nanoporous systems with concentration-dependent selectivity: Statistical mechanical modeling.

    PubMed

    García, Andrés; Wang, Jing; Windus, Theresa L; Sadow, Aaron D; Evans, James W

    2016-05-01

    Statistical mechanical modeling is developed to describe a catalytic conversion reaction A→B^{c} or B^{t} with concentration-dependent selectivity of the products, B^{c} or B^{t}, where reaction occurs inside catalytic particles traversed by narrow linear nanopores. The associated restricted diffusive transport, which in the extreme case is described by single-file diffusion, naturally induces strong concentration gradients. Furthermore, by comparing kinetic Monte Carlo simulation results with analytic treatments, selectivity is shown to be impacted by strong spatial correlations induced by restricted diffusivity in the presence of reaction and also by a subtle clustering of reactants, A.

  8. Catalytic conversion reactions in nanoporous systems with concentration-dependent selectivity: Statistical mechanical modeling

    NASA Astrophysics Data System (ADS)

    García, Andrés; Wang, Jing; Windus, Theresa L.; Sadow, Aaron D.; Evans, James W.

    2016-05-01

    Statistical mechanical modeling is developed to describe a catalytic conversion reaction A →Bc or Bt with concentration-dependent selectivity of the products, Bc or Bt, where reaction occurs inside catalytic particles traversed by narrow linear nanopores. The associated restricted diffusive transport, which in the extreme case is described by single-file diffusion, naturally induces strong concentration gradients. Furthermore, by comparing kinetic Monte Carlo simulation results with analytic treatments, selectivity is shown to be impacted by strong spatial correlations induced by restricted diffusivity in the presence of reaction and also by a subtle clustering of reactants, A .

  9. An evaluation of spectrally selective reflectors (cold mirror membranes) for use with concentrator solar arrays

    NASA Astrophysics Data System (ADS)

    Beauchamp, W. T.; Rancourt, J. D.; Lott, D. R.

    1980-06-01

    Spectrally selective reflector (SSR) coatings on lightweight transparent membranes were evaluated as a method of concentrating light for achieving increased power without suffering severe temperature losses on solar arrays. Analysis and laboratory tests indicate that SSR concentrators are more effective than opaque reflectors with both silicon and GaAs cells for increasing array output. Large area SSR membranes can be produced in roll to roll coaters at cost that will be competitive with other reflecting membranes.

  10. Positive Selection Linked with Generation of Novel Mammalian Dentition Patterns.

    PubMed

    Machado, João Paulo; Philip, Siby; Maldonado, Emanuel; O'Brien, Stephen J; Johnson, Warren E; Antunes, Agostinho

    2016-01-01

    A diverse group of genes are involved in the tooth development of mammals. Several studies, focused mainly on mice and rats, have provided a detailed depiction of the processes coordinating tooth formation and shape. Here we surveyed 236 tooth-associated genes in 39 mammalian genomes and tested for signatures of selection to assess patterns of molecular adaptation in genes regulating mammalian dentition. Of the 236 genes, 31 (∼13.1%) showed strong signatures of positive selection that may be responsible for the phenotypic diversity observed in mammalian dentition. Mammalian-specific tooth-associated genes had accelerated mutation rates compared with older genes found across all vertebrates. More recently evolved genes had fewer interactions (either genetic or physical), were associated with fewer Gene Ontology terms and had faster evolutionary rates compared with older genes. The introns of these positively selected genes also exhibited accelerated evolutionary rates, which may reflect additional adaptive pressure in the intronic regions that are associated with regulatory processes that influence tooth-gene networks. The positively selected genes were mainly involved in processes like mineralization and structural organization of tooth specific tissues such as enamel and dentin. Of the 236 analyzed genes, 12 mammalian-specific genes (younger genes) provided insights on diversification of mammalian teeth as they have higher evolutionary rates and exhibit different expression profiles compared with older genes. Our results suggest that the evolution and development of mammalian dentition occurred in part through positive selection acting on genes that previously had other functions. PMID:27613398

  11. Positive Selection Linked with Generation of Novel Mammalian Dentition Patterns.

    PubMed

    Machado, João Paulo; Philip, Siby; Maldonado, Emanuel; O'Brien, Stephen J; Johnson, Warren E; Antunes, Agostinho

    2016-09-11

    A diverse group of genes are involved in the tooth development of mammals. Several studies, focused mainly on mice and rats, have provided a detailed depiction of the processes coordinating tooth formation and shape. Here we surveyed 236 tooth-associated genes in 39 mammalian genomes and tested for signatures of selection to assess patterns of molecular adaptation in genes regulating mammalian dentition. Of the 236 genes, 31 (∼13.1%) showed strong signatures of positive selection that may be responsible for the phenotypic diversity observed in mammalian dentition. Mammalian-specific tooth-associated genes had accelerated mutation rates compared with older genes found across all vertebrates. More recently evolved genes had fewer interactions (either genetic or physical), were associated with fewer Gene Ontology terms and had faster evolutionary rates compared with older genes. The introns of these positively selected genes also exhibited accelerated evolutionary rates, which may reflect additional adaptive pressure in the intronic regions that are associated with regulatory processes that influence tooth-gene networks. The positively selected genes were mainly involved in processes like mineralization and structural organization of tooth specific tissues such as enamel and dentin. Of the 236 analyzed genes, 12 mammalian-specific genes (younger genes) provided insights on diversification of mammalian teeth as they have higher evolutionary rates and exhibit different expression profiles compared with older genes. Our results suggest that the evolution and development of mammalian dentition occurred in part through positive selection acting on genes that previously had other functions.

  12. Selection and generation of waveforms for differential mobility spectrometry

    SciTech Connect

    Krylov, Evgeny V.; Coy, Stephen L.; Nazarov, Erkinjon G.; Vandermey, John; Schneider, Bradley B.; Covey, Thomas R.

    2010-02-15

    Devices based on differential mobility spectrometry (DMS) are used in a number of ways, including applications as ion prefilters for API-MS systems, as detectors or selectors in hybrid instruments (GC-DMS, DMS-IMS), and in standalone systems for chemical detection and identification. DMS ion separation is based on the relative difference between high field and low field ion mobility known as the alpha dependence, and requires the application of an intense asymmetric electric field known as the DMS separation field, typically in the megahertz frequency range. DMS performance depends on the waveform and on the magnitude of this separation field. In this paper, we analyze the relationship between separation waveform and DMS resolution and consider feasible separation field generators. We examine ideal and practical DMS separation field waveforms and discuss separation field generator circuit types and their implementations. To facilitate optimization of the generator designs, we present a set of relations that connect ion alpha dependence to DMS separation fields. Using these relationships we evaluate the DMS separation power of common generator types as a function of their waveform parameters. Optimal waveforms for the major types of DMS separation generators are determined for ions with various alpha dependences. These calculations are validated by comparison with experimental data.

  13. Informing Selection of Nanomaterial Concentrations for ToxCast In Vitro Testing using the Multi-Path Particle Dosimetry Model

    EPA Science Inventory

    Currently, little justification is provided for nanomaterial testing concentrations in in vitro assays. The in vitro concentrations typically used may be higher than those experienced in exposed humans. Selection of concentration levels for hazard evaluation based on real-world ...

  14. Diffraction gratings generating orders with selective states of polarization.

    PubMed

    Davis, Jeffrey A; Moreno, Ignacio; Sánchez-López, María M; Badham, Katherine; Albero, Jorge; Cottrell, Don M

    2016-01-25

    We propose specially designed double anisotropic polarization diffraction gratings capable of producing a selective number of diffraction orders and with selective different states of polarization. Different polarization diffraction gratings are demonstrated, including linear polarization with horizontal, vertical and ± 45° orientations, and circular R and L polarization outputs. When illuminated with an arbitrary state of polarization, the system acts as a complete polarimeter where the intensities of the diffraction orders allow measurement of the Stokes parameters with a single shot. Experimental proof-of-concept is presented using a parallel-aligned liquid crystal display operating in a double pass architecture.

  15. Fluidized Bed Selective Oxidation-Sulfation Roasting of Nickel Sulfide Concentrate: Part I. Oxidation Roasting

    NASA Astrophysics Data System (ADS)

    Yu, Dawei; Utigard, Torstein A.; Barati, Mansoor

    2014-04-01

    Two-stage oxidation-sulfation roasting of nickel sulfide concentrate in fluidized bed was investigated to generate water-soluble metal sulfates as an alternative process to smelting of the sulfide concentrate for the recovery of valuable metals. The first stage, i.e., oxidation roasting, was employed to preferentially oxidize the iron before performing sulfation roasting. A batch fluidized bed roaster was constructed for roasting tests. Roasting products from various roasting temperatures and different roasting times were analyzed by SEM/EDS, EPMA, XRD, and ICP-OES to investigate the oxidation roasting behavior of the nickel concentrate as a function of temperature and time.

  16. Selection of respiratory protection devices for use in very high concentrations of airborne plutonium.

    PubMed

    Bianconi, C J

    2000-08-01

    This paper focuses on the proper selection of respiratory protection devices for use in very high concentrations of airborne plutonium. Special attention is given to the determination of levels at which airborne plutonium presents a hazard that is immediately dangerous to life or health. PMID:10910403

  17. 2-layer based microfluidic concentration generator by hybrid serial and volumetric dilutions.

    PubMed

    Lee, Kangsun; Kim, Choong; Kim, Youngeun; Jung, Keunhui; Ahn, Byungwook; Kang, Ji Yoon; Oh, Kwang W

    2010-04-01

    We present a 2-layer based microfluidic concentration generator by a hybrid of a serial and a volumetric dilution for dose-response experiments in drug screening. The hybrid dilution method using 2-layer based microfluidic network significantly reduces the total number of cascaded serial dilution stages. The proposed strategy is capable of generating a large number of universal stepwise monotonic concentrations with a wide range of logarithmic and linear scales. We have studied an equivalent electrical circuit to that of the 2-layer based microfluidic network, where the only variable parameter is channel length. We have designed a microfluidic dilution generator simultaneously covering 14 doses with a combination of 4-order logarithmic and 4-point linear concentrations. The design has been verified by a commercial circuit analysis software (e.g., P-Spice) for the electrical circuit analysis and a computational fluid dynamics software (e.g., CFD-ACE+) for the microfluidic circuit analysis. As a real-life application of the proposed dilution generator, we have successfully performed a dose-response experiment using MCF-7 human breast cancer cells. We expect that the proposed dilution method will be useful to study not only high throughput drug screening but also optimization in biology, chemistry, medicine, and material sciences.

  18. [Electricity generation using high concentration terephthalic acid solution by microbial fuel cell].

    PubMed

    Ye, Ye-Jie; Song, Tian-Shun; Xu, Yuan; Chen, Ying-Wen; Zhu, She-Min; Shen, Shu-Bao

    2009-04-15

    The high concentration terephthalic acid (TA) solution as the substrate of microbial fuel cell (MFC) was studied to generate electricity. The open circuit voltage was 0.54 V after inoculating for 210 h with anaerobic activated sludge, which proved that TA can be the substrate of microbial fuel cell to generate electricity. The influence of pH and substrate concentration on generating electricity was studied deeply. The voltage output of external resistance (R = 1,000 Omega) was the highest when pH was 8.0. It increased as the substrate concentration increasing and tended towards a maximum value. The maximum voltage output Umax was 0.5 V and Ks was 785.2 mg/L by Monod equation regression. When the substrate concentration (according to COD) was 4000 mg/L, the maximum power density was 96.3 mW/m2, coulomb efficiency was 2.66% and COD removal rate was 80.3%.

  19. Efficient key frames selection for panorama generation from video

    NASA Astrophysics Data System (ADS)

    Fadaeieslam, Mohammad Javad; Soryani, Mohsen; Fathy, Mahmood

    2011-04-01

    A video sequence consists of several hundred frames, and as a result, creating a panoramic image from these frames is a very time-consuming process. Consecutive frames have large overlap areas that do not provide much information. Therefore, some key frames must be extracted for better performance. There are a number of methods for key-frame selection that match all frames in a video sequence. We present a novel and efficient method to select key frames from video for creating a large panoramic mosaic without matching all frames. Consecutive frames are transformed and projected onto the common mosaic surface and the position of each corner of the next frame is predicted with a distinct Kalman filter on this surface. The overlap area between each predicted frame and its previous key frame is used as the criterion to select the next key frame. This method uses video information to reduce features and align frames with repeated structures more accurately. We show that this approach is an efficient preprocessing step and substantially reduces the time required to construct panorama from a video sequence.

  20. Selective electrochemical generation of hydrogen peroxide from water oxidation

    DOE PAGES

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, wemore » show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H2O2 and the 4e– oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.« less

  1. Selective electrochemical generation of hydrogen peroxide from water oxidation

    SciTech Connect

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H2O2 and the 4e– oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.

  2. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation.

    PubMed

    Viswanathan, Venkatasubramanian; Hansen, Heine A; Nørskov, Jens K

    2015-11-01

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.

  3. Frequency Selective Surface Bandpass Filters Applied To Thermophotovoltaic Generators

    NASA Astrophysics Data System (ADS)

    Horne, W. E.; Morgan, Mark D.; Horne, W. Paul; Sundaram, Vasan S.

    2004-11-01

    EDTEK, Inc. is developing three TPV applications, a portable diesel fueled generator for military and remote users, a hybrid solar-gas fueled power system intended for light industry and commercial 24-hour use, and a radioisotope fueled generator for deep-space spacecraft. The application of FSS bandpass filters for spectral control in these three different TPV applications has been analyzed. It has been determined that the design of the filter cannot be evaluated solely on the parameters of the filter itself. The interactions between the filter and the emitter and the TPV cells must be taken into account. In addition to the technical analysis of the converter, the overall system losses must be included in the analysis and the design requirements such as fuel efficiency, weight, generator size, cost and other factors must be included in the analysis. The analysis shows that the FSS filters are useful for producing the three systems with good efficiencies; however, different designs are required for the filters for each application.

  4. Effects of Problem Scope and Creativity Instructions on Idea Generation and Selection

    ERIC Educational Resources Information Center

    Rietzschel, Eric F.; Nijstad, Bernard A.; Stroebe, Wolfgang

    2014-01-01

    The basic assumption of brainstorming is that increased quantity of ideas results in increased generation as well as selection of creative ideas. Although previous research suggests that idea quantity correlates strongly with the number of good ideas generated, quantity has been found to be unrelated to the quality of selected ideas. This article…

  5. Oxygen Concentration Flammability Thresholds of Selected Aerospace Materials Considered for the Constellation Program

    NASA Technical Reports Server (NTRS)

    Hirsch, David B.; Williams, James H.; Harper, Susan A.; Beeson, Harold; Pedley, Michael D.

    2007-01-01

    Materials selection for spacecraft is based on an upward flammability test conducted in a quiescent environment in the highest expected oxygen concentration environment. The test conditions and its pass/fail test logic do not provide sufficient quantitative materials flammability information for an advanced space exploration program. A modified approach has been suggested determination of materials self-extinguishment limits. The flammability threshold information will allow NASA to identify materials with increased flammability risk from oxygen concentration and total pressure changes, minimize potential impacts, and allow for development of sound requirements for new spacecraft and extraterrestrial landers and habitats. This paper provides data on oxygen concentration self-extinguishment limits under quiescent conditions for selected materials considered for the Constellation Program.

  6. Trace Explosives Vapor Generation and Quantitation at Parts per Quadrillion Concentrations.

    PubMed

    Giordano, Braden C; Field, Christopher R; Andrews, Benjamin; Lubrano, Adam; Woytowitz, Morgan; Rogers, Duane; Collins, Greg E

    2016-04-01

    The generation of trace 2,4,6-trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX), and pentaerythritol tetranitrate (PETN) vapors using a pneumatically modulated liquid delivery system (PMLDS) coupled to a polytetrafluoroethylene (PTFE) total-consumption micronebulizer is presented. The vapor generator operates in a continuous manner with final vapor concentrations proportional to the explosive concentration in aqueous solution delivered through the nebulizer and the diluent air flow rate. For quantitation of concentrations in the parts per billionvolume (ppbv) to parts per trillionvolume (pptrv) range, Tenax-TA thermal desorption tubes were used for vapor collection with subsequent analysis on a thermal-desorption system programmable-temperature vaporization gas chromatograph (TDS-PTV-GC) with a μ-ECD detector. With 30 min sample times and an average sampling rate of 100 mL min(-1), vapor concentrations of 38 pptrv for TNT, 25 pptrv for RDX, and 26 pptrv for PETN were determined. For parts per quadrillionvolume (ppqv) vapor quantitation of TNT and RDX, an online PTV-GC system with a negative-ion chemical ionization mass spectrometer (methane reagent gas) was used for direct sampling and capture of the vapor on the PTV inlet. Vapor concentrations as low as 160 ppqv and 710 ppqv for TNT and RDX were quantified, respectively, with an instrument duty cycle as low as 4 min. PMID:26971624

  7. RESULTS OF ANALYSIS OF NGS CONCENTRATE DRUM SAMPLES [Next Generation Solvent

    SciTech Connect

    Peters, T.; Williams, M.

    2013-09-13

    Savannah River National Laboratory (SRNL) prepared two drums (50 gallons each in Drum#2 and Drum#4) of NGS-MCU (Next Generation Solvent-Modular CSSX Unit) concentrate for future use at MCU in downblending the BOBCalixC6 based solvent to produce NGS-MCU solvent. Samples of each drum were sent for analysis. The results of all the analyses indicate that the blend concentrate is of the correct composition and should produce a blended solvent at MCU of the desired formulation.

  8. New-generation concentrator modules based on cascade solar cells: Design and optical and thermal properties

    NASA Astrophysics Data System (ADS)

    Andreev, V. M.; Davidyuk, N. Yu.; Malevski, D. A.; Pan'chak, A. N.; Rumyantsev, V. D.; Sadchikov, N. A.; Chekalin, A. V.; Luque, A.

    2014-11-01

    New-generation concentrator modules use III-V nanoheterostructure cascade solar cells the efficiency of which can be raised to 50% for the number of cascades exceeding three. To obtain a high overall efficiency of photovoltaic conversion in power plants and extend their service time, it is necessary that the design of the modules be optimal in terms of optics and thermal engineering. In this work, main challenges in designing solar modules, such as optical concentration of radiation and residual heat removal, are considered. The results of pilot works that have been recently done in the Ioffe Physical Technical Institute are primarily reported.

  9. Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation

    SciTech Connect

    Reddy, Ramana G.

    2013-10-23

    The explicit UA program objective is to develop low melting point (LMP) molten salt thermal energy storage media with high thermal energy storage density for sensible heat storage systems. The novel Low Melting Point (LMP) molten salts are targeted to have the following characteristics: 1. Lower melting point (MP) compared to current salts (<222ºC) 2. Higher energy density compared to current salts (>300 MJ/m3) 3. Lower power generation cost compared to current salt In terms of lower power costs, the program target the DOE's Solar Energy Technologies Program year 2020 goal to create systems that have the potential to reduce the cost of Thermal Energy Storage (TES) to less than $15/kWh-th and achieve round trip efficiencies greater than 93%. The project has completed the experimental investigations to determine the thermo-physical, long term thermal stability properties of the LMP molten salts and also corrosion studies of stainless steel in the candidate LMP molten salts. Heat transfer and fluid dynamics modeling have been conducted to identify heat transfer geometry and relative costs for TES systems that would utilize the primary LMP molten salt candidates. The project also proposes heat transfer geometry with relevant modifications to suit the usage of our molten salts as thermal energy storage and heat transfer fluids. The essential properties of the down-selected novel LMP molten salts to be considered for thermal storage in solar energy applications were experimentally determined, including melting point, heat capacity, thermal stability, density, viscosity, thermal conductivity, vapor pressure, and corrosion resistance of SS 316. The thermodynamic modeling was conducted to determine potential high temperature stable molten salt mixtures that have thermal stability up to 1000 °C. The thermo-physical properties of select potential high temperature stable (HMP) molten salt mixtures were also experimentally determined. All the salt mixtures align with the go

  10. Selective removal of arsenic and monovalent ions from brackish water reverse osmosis concentrate.

    PubMed

    Xu, Pei; Capito, Marissa; Cath, Tzahi Y

    2013-09-15

    Concentrate disposal and management is a considerable challenge for the implementation of desalination technologies, especially for inland applications where concentrate disposal options are limited. This study has focused on selective removal of arsenic and monovalent ions from brackish groundwater reverse osmosis (RO) concentrate for beneficial use and safe environmental disposal using in situ and pre-formed hydrous ferric oxides/hydroxides adsorption, and electrodialysis (ED) with monovalent permselective membranes. Coagulation with ferric salts is highly efficient at removing arsenic from RO concentrate to meet a drinking water standard of 10 μg/L. The chemical demand for ferric chloride however is much lower than ferric sulfate as coagulant. An alternative method using ferric sludge from surface water treatment plant is demonstrated as an efficient adsorbent to remove arsenic from RO concentrate, providing a promising low cost, "waste treat waste" approach. The monovalent permselective anion exchange membranes exhibit high selectivity in removing monovalent anions over di- and multi-valent anions. The transport of sulfate and phosphate through the anion exchange membranes was negligible over a broad range of electrical current density. However, the transport of divalent cations such as calcium and magnesium increases through monovalent permselective cation exchange membranes with increasing current density. Higher overall salt concentration reduction is achieved around limiting current density while higher normalized salt removal rate in terms of mass of salt per membrane area and applied energy is attained at lower current density because the energy unitization efficiency decreases at higher current density. PMID:23892312

  11. Selective removal of arsenic and monovalent ions from brackish water reverse osmosis concentrate.

    PubMed

    Xu, Pei; Capito, Marissa; Cath, Tzahi Y

    2013-09-15

    Concentrate disposal and management is a considerable challenge for the implementation of desalination technologies, especially for inland applications where concentrate disposal options are limited. This study has focused on selective removal of arsenic and monovalent ions from brackish groundwater reverse osmosis (RO) concentrate for beneficial use and safe environmental disposal using in situ and pre-formed hydrous ferric oxides/hydroxides adsorption, and electrodialysis (ED) with monovalent permselective membranes. Coagulation with ferric salts is highly efficient at removing arsenic from RO concentrate to meet a drinking water standard of 10 μg/L. The chemical demand for ferric chloride however is much lower than ferric sulfate as coagulant. An alternative method using ferric sludge from surface water treatment plant is demonstrated as an efficient adsorbent to remove arsenic from RO concentrate, providing a promising low cost, "waste treat waste" approach. The monovalent permselective anion exchange membranes exhibit high selectivity in removing monovalent anions over di- and multi-valent anions. The transport of sulfate and phosphate through the anion exchange membranes was negligible over a broad range of electrical current density. However, the transport of divalent cations such as calcium and magnesium increases through monovalent permselective cation exchange membranes with increasing current density. Higher overall salt concentration reduction is achieved around limiting current density while higher normalized salt removal rate in terms of mass of salt per membrane area and applied energy is attained at lower current density because the energy unitization efficiency decreases at higher current density.

  12. Ion concentration polarization in a single and open microchannel induced by a surface-patterned perm-selective film.

    PubMed

    Kim, Minseok; Jia, Mingjie; Kim, Taesung

    2013-03-01

    We describe a novel and simple mechanism for inducing ion concentration polarization (ICP) using a surface-patterned perm-selective nanoporous film like Nafion in single, open microchannels. Such a surface-patterned Nafion film can rapidly transport only cations from the anodic side to the cathodic side through the nanopore clusters so that it is possible to generate an ICP phenomenon near the Nafion film. In this work, we characterize transport phenomena and distributions of ion concentration under various electric fields near the Nafion film and show that single-channel based ICP (SC-ICP) is affected by Nafion film thicknesses, strengths of applied electric fields, and ionic strengths of buffer solutions. We also emphasize that SC-ICP devices have several advantages over previous dual-channel ICP (DC-ICP) devices: easy and simple fabrication processes, inherently leak-tight, simple experimental setup requiring only one pair of electrodes, stable and robust ICP induced rapidly, and low electrical resistances helping to avoid Joule heating, and membrane perm-selectivity breakdown but allowing as high bulk flow as an open, plain microchannel. As an example of applications, we demonstrate that SC-ICP devices not only have high potential in pre-concentrating proteins in massively parallel microchannels but also enable the concentration and lysis of bacterial cells simultaneously and continuously on a chip; therefore, proteins within the cells are extracted, separated from the concentrated cells and then pre-concentrated at a different location that is closer to the Nafion film. Hence, we believe that the SC-ICP devices have higher possibilities of being easily integrated with traditional microfluidic systems for analytical and biotechnological applications.

  13. Response to five generations of selection for growth performance traits in rainbow trout (Oncorhynchus mykiss)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A pedigreed rainbow trout population (~100 families per generation) was selected for five generations to improve growth performance to the standard ~500-gram US market weight and beyond (greater than 1 kg). Body weights (BW) were recorded each generation at 5, 8, 10, and 13 months post-hatch. Selec...

  14. Effect of oxygen concentration on microsomal oxidation of ethanol and generation of oxygen radicals.

    PubMed Central

    Puntarulo, S; Cederbaum, A I

    1988-01-01

    The iron-catalysed production of hydroxyl radicals, by rat liver microsomes (microsomal fractions), assessed by the oxidation of substrate scavengers and ethanol, displayed a biphasic response to the concentration of O2 (varied from 3 to 70%), reaching a maximal value with 20% O2. The decreased rates of hydroxyl-radical generation at lower O2 concentrations correlates with lower rates of production of H2O2, the precursor of hydroxyl radical, whereas the decreased rates at elevated O2 concentrations correlate with lower rates (relative to 20% O2) of activity of NADPH-cytochrome P-450 reductase, which reduces iron and is responsible for redox cycling of iron by the microsomes. The oxidation of aniline or aminopyrine and the cytochrome P-450/oxygen-radical-independent oxidation of ethanol also displayed a biphasic response to the concentration of O2, reaching a maximum at 20% O2, which correlates with the dithionite-reducible CO-binding spectra of cytochrome P-450. Microsomal lipid peroxidation increased as the concentration of O2 was raised from 3 to 7 to 20% O2, and then began to level off. This different pattern of malondialdehyde generation compared with hydroxyl-radical production probably reflects the lack of a role for hydroxyl radical in microsomal lipid peroxidation. These results point to the complex role for O2 in microsomal generation of oxygen radicals, which is due in part to the critical necessity for maintaining the redox state of autoxidizable components of the reaction system. PMID:3415646

  15. A serial dilution microfluidic device using a ladder network generating logarithmic or linear concentrations.

    PubMed

    Kim, Choong; Lee, Kangsun; Kim, Jong Hyun; Shin, Kyeong Sik; Lee, Kyu-Jung; Kim, Tae Song; Kang, Ji Yoon

    2008-03-01

    In this paper, we propose a serial dilution microfluidic chip which is able to generate logarithmic or linear step-wise concentrations. These concentrations were generated via adjustments in the flow rate of two converging fluids at the channel junctions of the ladder network. The desired dilution ratios are almost independent of the flow rate or diffusion length of molecules, as the dilution device is influenced only by the ratio of volumetric flow rates. Given a set of necessary dilution ratios, whether linear or logarithmic, a serial dilution chip can be constructed via the modification of a microfluidic resistance network. The design principle was suggested and both the logarithmic and linear dilution chips were fabricated in order to verify their performance in accordance with the fluorescence intensity. The diluted concentrations of a fluorescein solution in the microfluidic device evidenced relatively high linearity, and the cytotoxicity test of MCF-7 breast cancer cells via the logarithmic dilution chip was generally consistent with the results generated with manual dilution.

  16. Apparatus for generating coherent infrared energy of selected wavelength

    DOEpatents

    Stevens, C.G.

    A tunable source of coherent infrared energy includes a heat pipe having an intermediate region at which cesium is heated to vaporizing temperature and end regions at which the vapor is condensed and returned to the intermediate region for reheating and recirculation. Optical pumping light is directed along the axis of the heat pipe through a first end window to stimulate emission of coherent infrared energy which is transmitted out through an opposite end window. A porous walled tubulation extends along the axis of the heat pipe and defines a region in which cesium vapor is further heated to a temperature sufficient to dissociate cesium dimers which would decrease efficiency by absorbing pump light. Efficient generation of any desired infrared wavelength is realized by varying the wavelength of the pump light.

  17. Apparatus for generating coherent infrared energy of selected wavelength

    DOEpatents

    Stevens, Charles G.

    1985-01-01

    A tunable source (11) of coherent infrared energy includes a heat pipe (12) having an intermediate region (24) at which cesium (22) is heated to vaporizing temperature and end regions (27, 28) at which the vapor is condensed and returned to the intermediate region (24) for reheating and recirculation. Optical pumping light (43) is directed along the axis of the heat pipe (12) through a first end window (17) to stimulate emission of coherent infrared energy which is transmitted out through an opposite end window (18). A porous walled tubulation (44) extends along the axis of the heat pipe (12) and defines a region (46) in which cesium vapor is further heated to a temperature sufficient to dissociate cesium dimers which would decrease efficiency by absorbing pump light (43). Efficient generation of any desired infrared wavelength is realized by varying the wavelength of the pump light (43).

  18. NEXT GENERATION NUCLEAR PLANT LICENSING BASIS EVENT SELECTION WHITE PAPER

    SciTech Connect

    Mark Holbrook

    2010-09-01

    The Next Generation Nuclear Plant (NGNP) will be a licensed commercial high temperature gas-cooled reactor (HTGR) plant capable of producing the electricity and high temperature process heat for industrial markets supporting a range of end-user applications. The NGNP Project has adopted the 10 CFR 52 Combined License (COL) application process, as recommended in the Report to Congress, dated August 2008, as the foundation for the NGNP licensing strategy. NRC licensing of the NGNP plant utilizing this process will demonstrate the efficacy of licensing future HTGRs for commercial industrial applications. This white paper is one in a series of submittals that will address key generic issues of the COL priority licensing topics as part of the process for establishing HTGR regulatory requirements.

  19. System and method for generating current by selective electron heating

    DOEpatents

    Fisch, Nathaniel J.; Boozer, Allen H.

    1984-01-01

    A system for the generation of toroidal current in a plasma which is prepared in a toroidal magnetic field. The system utilizes the injection of high-frequency waves into the plasma by means of waveguides. The wave frequency and polarization are chosen such that when the waveguides are tilted in a predetermined fashion, the wave energy is absorbed preferentially by electrons traveling in one toroidal direction. The absorption of energy in this manner produces a toroidal electric current even when the injected waves themselves do not have substantial toroidal momentum. This current can be continuously maintained at modest cost in power and may be used to confine the plasma. The system can operate efficiently on fusion grade tokamak plasmas.

  20. Photothermolysis by laser-induced microbubbles generated around gold nanorod clusters selectively formed in leukemia cells

    NASA Astrophysics Data System (ADS)

    Lapotko, Dmitri; Lukianova-Hleb, Ekaterina; Zhdanok, Sergei; Rostro, Betty; Simonette, Rebecca; Hafner, Jason; Konopleva, Marina; Andreeff, Michael; Conjusteau, Andre; Oraevsky, Alexander

    2008-02-01

    In an effort of developing clinical LANTCET (laser-activated nano-thermolysis as cell elimination technology) we achieved selective destruction of individual tumor cells through laser generation of vapor microbubbles around clusters of light absorbing gold nanorods (GNR) selectively formed in target tumor cells. Among all gold nanoparticles, nanorods offer the highest optical absorption in the near-infrared. We applied covalent conjugates of gold nanorods with targeting vectors such as monoclonal antibodies CD33 (specific for Acute Myeloid Leukemia), while GNR conjugates with polyethylene-glycol (PEG) were used as nonspecific targeting control. GNR clusters were formed inside the tumor cells at 37 °C due to endocytosis of large concentration of nanorods accumulated on the surface of tumor cells targeted at 4 °C. Formation of GNR clusters significantly reduces the threshold of tumor cell damage making LANTCET safe for normal cells. Appearance of GNR clusters was verified directly with optical resonance scattering microscopy. LANTCET was performed in vitro with living cells of (1) model myeloid K562 cells (CD33 positive), (2) primary human bone marrow CD33-positive blast cells from patients diagnosed with acute myeloid leukemia. Laser-induced microbubbles were generated and detected with a photothermal microscope equipped with a tunable Ti-Sa pulsed laser. GNT cluster formation caused a 100-fold decrease in the threshold optical fluence for laser microbubble generation in tumor cells compared with that in normal cells under the same targeting and irradiation conditions. Combining imaging based on resonance optical scattering with photothermal imaging of microbubbles, we developed a method for detection, image-guided treatment and monitoring of LANTCET. Pilot experiments were performed in flow mode bringing LANTCET closer to reality of clinical procedure of purging tumor cells from bone marrow grafts.

  1. Adolescent Body Image Distortion: A Consideration of Immigrant Generational Status, Immigrant Concentration, Sex and Body Dissatisfaction.

    PubMed

    Kimber, Melissa; Georgiades, Katholiki; Couturier, Jennifer; Jack, Susan M; Wahoush, Olive

    2015-11-01

    Immigrant adolescents represent a significant and growing proportion of the population in the United States. Yet, little is known about their experiences of body image distortion. This is particularly concerning given that body image distortion has been identified as a significant and modifiable risk factor for a number of mental illnesses, including depression and eating disorders. This study uses multi-level modeling to examine the associations between immigrant generational status, neighborhood immigrant concentration, sex, body dissatisfaction and risk for body image distortion. Data come from the National Longitudinal Study of Adolescent Health and includes 10,962 11-19 year olds (49.6 % female). First generation immigrant females were significantly more likely than 3rd generation-or-later adolescents to experience underweight body image distortion. There was no association between neighborhood immigrant concentration and risk for body image distortion. Body dissatisfaction was associated with greater risk for underweight and overweight body image distortion, with the magnitude of underweight distortion risk significantly greater among 1st generation immigrants. Interventions that encourage the development of a healthy body image have the potential to reduce the onset and duration of body image distortion among immigrant and non-immigrant adolescents. PMID:26194338

  2. Adolescent Body Image Distortion: A Consideration of Immigrant Generational Status, Immigrant Concentration, Sex and Body Dissatisfaction.

    PubMed

    Kimber, Melissa; Georgiades, Katholiki; Couturier, Jennifer; Jack, Susan M; Wahoush, Olive

    2015-11-01

    Immigrant adolescents represent a significant and growing proportion of the population in the United States. Yet, little is known about their experiences of body image distortion. This is particularly concerning given that body image distortion has been identified as a significant and modifiable risk factor for a number of mental illnesses, including depression and eating disorders. This study uses multi-level modeling to examine the associations between immigrant generational status, neighborhood immigrant concentration, sex, body dissatisfaction and risk for body image distortion. Data come from the National Longitudinal Study of Adolescent Health and includes 10,962 11-19 year olds (49.6 % female). First generation immigrant females were significantly more likely than 3rd generation-or-later adolescents to experience underweight body image distortion. There was no association between neighborhood immigrant concentration and risk for body image distortion. Body dissatisfaction was associated with greater risk for underweight and overweight body image distortion, with the magnitude of underweight distortion risk significantly greater among 1st generation immigrants. Interventions that encourage the development of a healthy body image have the potential to reduce the onset and duration of body image distortion among immigrant and non-immigrant adolescents.

  3. Modeling breathing-zone concentrations of airborne contaminants generated during compressed air spray painting.

    PubMed

    Flynn, M R; Gatano, B L; McKernan, J L; Dunn, K H; Blazicko, B A; Carlton, G N

    1999-01-01

    This paper presents a mathematical model to predict breathing-zone concentrations of airborne contaminants generated during compressed air spray painting in cross-flow ventilated booths. The model focuses on characterizing the generation and transport of overspray mist. It extends previous work on conventional spray guns to include exposures generated by HVLP guns. Dimensional analysis and scale model wind-tunnel studies are employed using non-volatile oils, instead of paint, to produce empirical equations for estimating exposure to total mass. Results indicate that a dimensionless breathing zone concentration is a nonlinear function of the ratio of momentum flux of air from the spray gun to the momentum flux of air passing through the projected area of the worker's body. The orientation of the spraying operation within the booth is also very significant. The exposure model requires an estimate of the contaminant generation rate, which is approximated by a simple impactor model. The results represent an initial step in the construction of more realistic models capable of predicting exposure as a mathematical function of the governing parameters. PMID:10028895

  4. Use of an adjustable microfluidic droplet generator to produce uniform emulsions with different concentrations

    NASA Astrophysics Data System (ADS)

    Yeh, Chia-Hsien; Lin, Yu-Cheng

    2013-12-01

    The adjustable microfluidic droplet generator (ADG) described herein successfully uses a micro-mixer and a flow-focusing device to produce water droplets with eleven different trypan blue concentrations under various flow rate ratios of the trypan blue solution (sample phase 1, w1) and D.I. water (sample phase 2, w2) and uses these chitosan microparticles to encapsulate the magnetic nanoparticles. These eleven trypan blue/water droplet variations are uniform in size, with a coefficient of variation less than 10%, and can be precisely controlled by adjusting the sum of the sample phase flow rates (w1+w2) and the oil phase flow rate. Chitosan emulsions with eleven different Fe3O4 nanoparticle concentrations are used for magnetic targets, with the chitosan microparticles ranging from 44 to 83 µm in diameter. The ADG has the advantages of active droplet diameter control, the generation of droplets of uniform and specific size with different concentrations and the simplicity of the process. This preparation approach for chitosan microparticles with eleven different concentrations has many potential applications in drug delivery and pharmaceuticals.

  5. Low concentrations of metal mixture exposures have adverse effects on selected biomarkers of Xenopus laevis tadpoles.

    PubMed

    Yologlu, Ertan; Ozmen, Murat

    2015-11-01

    Polluted ecosystems may contain mixtures of metals, such that the combinations of metals, even in low concentrations, may cause adverse effects. In the present study, we focused on toxic effects of mixtures of selected metals, the LC50 values, and also their safety limit in aquatic systems imposed by the European legislation using a model organism. Xenopus laevis tadpoles were used as test organisms. They were exposed to metals or their combinations due to 96-h LC50 values. Glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated. Metallothionein concentrations were also determined. The LC50s for Cd, Pb, and Cu were calculated as 5.81mg AI/L, 123.05mg AI/L, and 0.85mg AI/L, respectively. Low lethality ratios were observed with unary exposure of each metal in lower concentrations. Double or triple combinations of LC50 and LC50/2 concentrations caused 100% lethality with Cd+Cu and Pb+Cd+Cu mixtures, while the Pb+Cu mixture also caused high lethal ratios. The selected enzyme activities were significantly affected by metals or mixtures, and dose-related effects were determined. The metallothionein levels generally increased as related to concentration in unary metals and mixtures. Acceptable limit values of unary metals and mixtures did not significantly change metallothionein levels. The results suggest that oxidative stress-related mechanisms are involved in the toxicity induced by selected metals with combinations of very low concentrations.

  6. The evolution of aggression: can selection generate variability?

    PubMed

    Maynard Smith, J; Harper, D G

    1988-07-01

    Three models--the war of attrition, the size game and the badges of dominance game--are described, in which natural selection can maintain genetic variability for aggression. The models differ in whether or not the traits that settle contests are costly in contexts other than fighting, and also in whether signals are used. It is concluded that contests will be settled by non-costly traits only if the value of the contested resource is small relative to the cost of fighting, and that 'honest' signalling of aggressiveness is stable only if individuals giving signals that are inconsistent with their behaviour suffer costs. The literature on 'badges of dominance' in birds is reviewed. New data on great tits, greenfinches and corn buntings show that there is plumage variability within age and sex that sometimes serves to settle contests, and that, in the first two species but not the third, the badges are uncorrelated with size, and settle contests only over trivial resources.

  7. Size-selective DNA separation: recovery spectra help determine the sodium chloride (NaCl) and polyethylene glycol (PEG) concentrations required.

    PubMed

    He, Zhangyong; Xu, Hong; Xiong, Min; Gu, Hongchen

    2014-10-01

    In the presence of sodium chloride (NaCl), DNA fragments can be size-selectively separated by varying the final concentration of polyethylene glycol (PEG). This separation strategy in combination with the use of paramagnetic particles provides a valuable platform for achieving the desired DNA size interval, which is important in automated library preparation for high-throughput DNA sequencing. Here, we report the establishment of recovery spectra of DNA fragments that enable the determination of suitable NaCl and PEG concentrations for size-selective separation. Firstly, at a given NaCl concentration, the recovery equation was obtained by fitting the DNA recovery ratios versus the PEG concentrations using the logistic function to determine the required parameters. Secondly, the slope function of the recovery equation was achieved by deducing its first derivative. Therefore, the recovery spectrum can be generated using the slope function based on those parameters. According to the recovery spectra of different length DNA fragments, suitable NaCl and PEG concentrations can be determined, respectively, by calculating their resolution values and recovery ratios. The strategy was effectively applied to the size-selective separation of 532-, 400-, and 307-bp fragments at the selected reagent concentrations with recoveries of 96.9, 64.7, and 85.9%, respectively. Our method enables good predictions of NaCl and PEG concentrations for size-selective DNA separation.

  8. Generative model selection using a scalable and size-independent complex network classifier

    SciTech Connect

    Motallebi, Sadegh Aliakbary, Sadegh Habibi, Jafar

    2013-12-15

    Real networks exhibit nontrivial topological features, such as heavy-tailed degree distribution, high clustering, and small-worldness. Researchers have developed several generative models for synthesizing artificial networks that are structurally similar to real networks. An important research problem is to identify the generative model that best fits to a target network. In this paper, we investigate this problem and our goal is to select the model that is able to generate graphs similar to a given network instance. By the means of generating synthetic networks with seven outstanding generative models, we have utilized machine learning methods to develop a decision tree for model selection. Our proposed method, which is named “Generative Model Selection for Complex Networks,” outperforms existing methods with respect to accuracy, scalability, and size-independence.

  9. DEVELOPMENT OF ANALYTICAL METHODS FOR DETERMINING SUPPRESSOR CONCENTRATION IN THE MCU NEXT GENERATION SOLVENT (NGS)

    SciTech Connect

    Taylor-Pashow, K.; Fondeur, F.; White, T.; Diprete, D.; Milliken, C.

    2013-07-31

    Savannah River National Laboratory (SRNL) was tasked with identifying and developing at least one, but preferably two methods for quantifying the suppressor in the Next Generation Solvent (NGS) system. The suppressor is a guanidine derivative, N,N',N"-tris(3,7-dimethyloctyl)guanidine (TiDG). A list of 10 possible methods was generated, and screening experiments were performed for 8 of the 10 methods. After completion of the screening experiments, the non-aqueous acid-base titration was determined to be the most promising, and was selected for further development as the primary method. {sup 1}H NMR also showed promising results from the screening experiments, and this method was selected for further development as the secondary method. Other methods, including {sup 36}Cl radiocounting and ion chromatography, also showed promise; however, due to the similarity to the primary method (titration) and the inability to differentiate between TiDG and TOA (tri-n-ocytlamine) in the blended solvent, {sup 1}H NMR was selected over these methods. Analysis of radioactive samples obtained from real waste ESS (extraction, scrub, strip) testing using the titration method showed good results. Based on these results, the titration method was selected as the method of choice for TiDG measurement. {sup 1}H NMR has been selected as the secondary (back-up) method, and additional work is planned to further develop this method and to verify the method using radioactive samples. Procedures for analyzing radioactive samples of both pure NGS and blended solvent were developed and issued for the both methods.

  10. High-efficiency concentration/multi-solar-cell system for orbital power generation

    NASA Technical Reports Server (NTRS)

    Onffroy, J. R.; Stoltzmann, D. E.; Lin, R. J. H.; Knowles, G. R.

    1980-01-01

    An analysis was performed to determine the economic feasibility of a concentrating spectrophotovoltaic orbital electrical power generation system. In this system dichroic beam-splitting mirrors are used to divide the solar spectrum into several wavebands. Absorption of these wavebands by solar cells with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat which must be rejected. The optical concentration is performed in two stages. The first concentration stage employs a Cassegrain-type telescope, resulting in a short system length. The output from this stage is directed to compound parabolic concentrators which comprise the second stage of concentration. Ideal efficiencies for one-, two-, three-, and four-cell systems were calculated under 1000 sun, AMO conditions, and optimum energy bands were determined. Realistic efficiencies were calculated for various combinations of Si, GaAs, Ge and GaP. Efficiencies of 32 to 33 percent were obtained with the multicell systems. The optimum system consists of an f/3.5 optical system, a beam splitter to divide the spectrum at 0.9 microns, and two solar cell arrays, GaAs and Si.

  11. SCARLET Photovoltaic Concentrator Array Selected for Flight Under NASA's New Millennium Program

    NASA Technical Reports Server (NTRS)

    Piszczor, Michael F., Jr.

    1997-01-01

    The NASA Lewis Research Center continues to demonstrate its expertise in the development and implementation of advanced space power systems. For example, during the past year, the NASA New Millennium Program selected the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) photovoltaic array as the power system for its Deep Space-1 (DS-1) mission. This Jet Propulsion Laboratory (JPL) managed DS-1 mission, which represents the first operational flight of a photovoltaic concentrator array, will provide a baseline for the use of this technology in a variety of future government and commercial applications. SCARLET is a joint NASA Lewis/Ballistic Missile Defense Organization program to develop advanced photovoltaic array technology that uses a unique refractive concentrator design to focus sunlight onto a line of photovoltaic cells located below the optical element. The general concept is based on previous work conducted at Lewis under a Small Business Innovation Research (SBIR) contract with AEC-Able Engineering, Inc., for the Multiple Experiments to Earth Orbit and Return (METEOR) spacecraft. The SCARLET II design selected by the New Millennium Program is a direct adaptation of the smaller SCARLET I array built for METEOR. Even though SCARLET I was lost during a launch failure in October 1995, the hardware (designed, built, and flight qualified within 6 months) provided invaluable information and experience that led to the selection of this technology as the primary power source for DS-1.

  12. TRANSPORT CHARACTERISTICS OF SELECTED PWR LOCA GENERATED DEBRIS.

    SciTech Connect

    A. K. MAJI; B. MARSHALL; ET AL

    2000-10-01

    subsequent accumulation of debris on the sump screen. The complete methodology will, of course, include a means of estimating debris generation, transport to the containment floor, transport to the sump screen, and the resulting loss of NPSH.

  13. Size-Selective Concentration of Chondrules and Other Small Particles in Protoplanetary Nebula Turbulence

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey N.; Hogan, Robert C.; Paque, Julie M.; Dobrovolskis, Anthony R.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Size-selective concentration of particles in a weakly turbulent protoplanetary nebula may be responsible for the initial collection of chondrules and other constituents into primitive bodY precursors. This paper presents the main elements of this process of turbulent concentration. In the terrestrial planet region. both the characteristic size and size distribution of chondrules are explained. "Fluffier" particles would be concentrated in nebula regions which were at a lower density and/or more intensely turbulent. The spatial distribution of concentrated particle density obeys multifractal scaling, suggesting a close tie to the turbulent cascade process. This scaling behavior allows predictions of the probability distributions for concentration in the protoplanetary nebula to be made. Large concentration factors (less than 10(exp 5)) are readily obtained, implying that numerous zones of particle density significantly exceeding the gas density could exist. If most of the available solids were actually in chondrule sized particles, the ensuing particle mass density would become so large that the feedback effects on gas turbulence due to mass loading could no longer be neglected. This paper describes the process, presenting its basic elements and some implications, without including the effects of mass loading.

  14. [Selective extraction of metals from zinc concentrate by association of chemolithotrophic bacteria].

    PubMed

    Vardanian, N S; Vardanian, A K

    2011-01-01

    Ability for selective extraction of copper and zinc from zinc concentrate using association of chemolithotrophic bacteria was investigated. In the presence of bacterial association, the rate of desalinization of zinc, copper, and iron was increased 3-fold, 4-5-fold, and 2-fold, respectively. Zinc, copper, and iron were levigated with the most significant rate. It was revealed that addition of Fe3+ 2 g/l resulted in reduction of iron desalinization and in 3-fold increase of desalinization rate of copper at constant dissolution rate of mineral zinc. It is suggested that the intensification of copper desalinization is connected with the activity of sulfur-oxidizing bacteria able to activate the mineral surface via elimination of passivation layer of elemental sulfur. It was concluded that sulfur-oxidizing bacteria play a significant role in copper desalinization from zinc concentrate. A unique strain of mesophile sulfur-oxidizing bacteria was isolated from desalinization pulp of zinc concentrate; in the perspective, it may serve as efficient candidate for performing of selective extraction of copper from zinc concentrate.

  15. Selecting reference concentrations for fish biliary PAH metabolites for stream ecological exposure assessment

    SciTech Connect

    Lin, E.L.C.; Cormier, S.M.; Subramanian, B.; Williams, D.; Wulfeck, K.; Detmer, S.; Lowry, M.E.

    1995-12-31

    Reference concentrations for two types of biliary PAH metabolites were empirically determined for two species of fish. Bile from white sucker and common carp were collected from streams in Ohio having poor to excellent condition based on a modified index of biotic integrity (MIBI). PAH were measured using fixed wavelength fluorescence with excitation/emission pairs at 290/335 nm for naphthalene-type (NAPH) and 380/430 nm for benzo[a]pyrene-type (B[a]P) metabolites. Exposures to PAH were estimated for petroleum sources with NAPH and from combustion sources with B[a]P. Three criteria were used to select reference concentrations. Site criteria were: an MIBI score of at least 30, relatively low median values of biliary PAH concentration, and low statistical variation. The median reference values selected were 0.5 {micro}g B[a]P/mg protein and 50 pg NAPH/mg protein for white sucker and 0.5 {micro}g B[a]P/mg protein and 90 {micro}g NAPH/mg protein for common carp. Of the 28 sites sampled with white sucker in 1993, 68% exceeded the reference value for NAPH and 32% for B[a]P. Of the 22 sites sampled with carp, 68% exceeded the value for NAPH and 41% for B[a]P. Likewise, more sites with MIBI scores between 30 and 60 exceeded the NAPH reference than the B[a]P reference concentration.

  16. [Selective extraction of metals from zinc concentrate by association of chemolithotrophic bacteria].

    PubMed

    Vardanian, N S; Vardanian, A K

    2011-01-01

    Ability for selective extraction of copper and zinc from zinc concentrate using association of chemolithotrophic bacteria was investigated. In the presence of bacterial association, the rate of desalinization of zinc, copper, and iron was increased 3-fold, 4-5-fold, and 2-fold, respectively. Zinc, copper, and iron were levigated with the most significant rate. It was revealed that addition of Fe3+ 2 g/l resulted in reduction of iron desalinization and in 3-fold increase of desalinization rate of copper at constant dissolution rate of mineral zinc. It is suggested that the intensification of copper desalinization is connected with the activity of sulfur-oxidizing bacteria able to activate the mineral surface via elimination of passivation layer of elemental sulfur. It was concluded that sulfur-oxidizing bacteria play a significant role in copper desalinization from zinc concentrate. A unique strain of mesophile sulfur-oxidizing bacteria was isolated from desalinization pulp of zinc concentrate; in the perspective, it may serve as efficient candidate for performing of selective extraction of copper from zinc concentrate. PMID:22232898

  17. Concentrations and geographic distribution of selected organic pollutants in Scottish surface soils.

    PubMed

    Rhind, S M; Kyle, C E; Kerr, C; Osprey, M; Zhang, Z L; Duff, E I; Lilly, A; Nolan, A; Hudson, G; Towers, W; Bell, J; Coull, M; McKenzie, C

    2013-11-01

    Concentrations of selected persistent organic pollutants (POPs) representing three chemical classes (polycyclic aromatic hydrocarbons (PAH), polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyls (PCB) and the organic pollutant diethylhexyl phthalate (DEHP), were determined in surface soil samples (0-5 cm) collected at 20 km grid intersects throughout Scotland over a three-year period. Detectable amounts of all chemical classes and most individual congeners were present in all samples. There were no consistent effects of soil or vegetation type, soil carbon content, pH, altitude or distance from centres of population on concentrations which exhibited extreme variation, even in adjacent samples. It is concluded that soil POPs and DEHP concentrations and associated rates of animal and human exposure were highly variable, influenced by multiple, interacting factors, and not clearly related to local sources but possibly related to wet atmospheric deposition and the organic carbon content of the soil.

  18. Measuring Selective Estrogen Receptor Modulator (SERM)–Membrane Interactions with Second Harmonic Generation

    PubMed Central

    2015-01-01

    The interaction of selective estrogen receptor modulators (SERMs) with lipid membranes has been measured at clinically relevant serum concentrations using the label-free technique of second harmonic generation (SHG). The SERMs investigated in this study include raloxifene, tamoxifen, and the tamoxifen metabolites 4-hydroxytamoxifen, N-desmethyltamoxifen, and endoxifen. Equilibrium association constants (Ka) were measured for SERMs using varying lipid compositions to examine how lipid phase, packing density, and cholesterol content impact SERM-membrane interactions. Membrane-binding properties of tamoxifen and its metabolites were compared on the basis of hydroxyl group substitution and amine ionization to elucidate how the degree of drug ionization impacts membrane partitioning. SERM-membrane interactions were probed under multiple pH conditions, and drug adsorption was observed to vary with the concentration of soluble neutral species. The agreement between Ka values derived from SHG measurements of the interactions between SERMs and artificial cell membranes and independent observations of the SERMs efficacy from clinical studies suggests that quantifying membrane adsorption properties may be important for understanding SERM action in vivo. PMID:24410282

  19. A Porous Tissue Engineering Scaffold Selectively Degraded by Cell-Generated Reactive Oxygen Species

    PubMed Central

    Martin, John R.; Gupta, Mukesh K.; Page, Jonathan M.; Yu, Fang; Davidson, Jeffrey M.; Guelcher, Scott A.

    2014-01-01

    Biodegradable tissue engineering scaffolds are commonly fabricated from poly(lactide-co-glycolide) (PLGA) or similar polyesters that degrade by hydrolysis. PLGA hydrolysis generates acidic breakdown products that trigger an accelerated, autocatalytic degradation mechanism that can create mismatched rates of biomaterial breakdown and tissue formation. Reactive oxygen species (ROS) are key mediators of cell function in both health and disease, especially at sites of inflammation and tissue healing, and induction of inflammation and ROS are natural components of the in vivo response to biomaterial implantation. Thus, polymeric biomaterials that are selectively degraded by cell-generated ROS may have potential for creating tissue engineering scaffolds with better matched rates of tissue in-growth and cell-mediated scaffold biodegradation. To explore this approach, a series of poly(thioketal) (PTK) urethane (PTK-UR) biomaterial scaffolds were synthesized that degrade specifically by an ROS-dependent mechanism. PTK-UR scaffolds had significantly higher compressive moduli than analogous poly(ester urethane) (PEUR) scaffolds formed from hydrolytically-degradable ester-based diols (p < 0.05). Unlike PEUR scaffolds, the PTK-UR scaffolds were stable under aqueous conditions out to 25 weeks but were selectively degraded by ROS, indicating that their biodegradation would be exclusively cell-mediated. The in vitro oxidative degradation rates of the PTK-URs followed first-order degradation kinetics, were significantly dependent on PTK composition (p < 0.05), and correlated to ROS concentration. In subcutaneous rat wounds, PTK-UR scaffolds supported cellular infiltration and granulation tissue formation, followed first-order degradation kinetics over 7 weeks, and produced significantly greater stenting of subcutaneous wounds compared to PEUR scaffolds. These combined results indicate that ROS-degradable PTK-UR tissue engineering scaffolds have significant advantages over analogous

  20. A porous tissue engineering scaffold selectively degraded by cell-generated reactive oxygen species.

    PubMed

    Martin, John R; Gupta, Mukesh K; Page, Jonathan M; Yu, Fang; Davidson, Jeffrey M; Guelcher, Scott A; Duvall, Craig L

    2014-04-01

    Biodegradable tissue engineering scaffolds are commonly fabricated from poly(lactide-co-glycolide) (PLGA) or similar polyesters that degrade by hydrolysis. PLGA hydrolysis generates acidic breakdown products that trigger an accelerated, autocatalytic degradation mechanism that can create mismatched rates of biomaterial breakdown and tissue formation. Reactive oxygen species (ROS) are key mediators of cell function in both health and disease, especially at sites of inflammation and tissue healing, and induction of inflammation and ROS are natural components of the in vivo response to biomaterial implantation. Thus, polymeric biomaterials that are selectively degraded by cell-generated ROS may have potential for creating tissue engineering scaffolds with better matched rates of tissue in-growth and cell-mediated scaffold biodegradation. To explore this approach, a series of poly(thioketal) (PTK) urethane (PTK-UR) biomaterial scaffolds were synthesized that degrade specifically by an ROS-dependent mechanism. PTK-UR scaffolds had significantly higher compressive moduli than analogous poly(ester urethane) (PEUR) scaffolds formed from hydrolytically-degradable ester-based diols (p < 0.05). Unlike PEUR scaffolds, the PTK-UR scaffolds were stable under aqueous conditions out to 25 weeks but were selectively degraded by ROS, indicating that their biodegradation would be exclusively cell-mediated. The in vitro oxidative degradation rates of the PTK-URs followed first-order degradation kinetics, were significantly dependent on PTK composition (p < 0.05), and correlated to ROS concentration. In subcutaneous rat wounds, PTK-UR scaffolds supported cellular infiltration and granulation tissue formation, followed first-order degradation kinetics over 7 weeks, and produced significantly greater stenting of subcutaneous wounds compared to PEUR scaffolds. These combined results indicate that ROS-degradable PTK-UR tissue engineering scaffolds have significant advantages over

  1. Preliminary characterization of ST2G: Solar thermionic-thermoelectric generator for concentrating systems

    NASA Astrophysics Data System (ADS)

    Bellucci, Alessandro; Calvani, Paolo; Cappelli, Emilia; Orlando, Stefano; Sciti, Diletta; Yogev, Ronen; Kribus, Abraham; Trucchi, Daniele M.

    2015-06-01

    An innovative conversion module (CM) for concentrating solar power applications, named ST2G (Solar Thermionic-Thermoelectric Generator), has been developed and fabricated. The new technology is based on a solid-state converter that works at temperatures up to 1000 °C and exploits a double conversion stage: a thermionic stage and a thermoelectric one, connected thermally in series. Potentially, the CM could reach a combined solar energy-to-electrical efficiency larger than 30%, producing also additional thermal energy to be exploited as a co-generation. Different prototypes have been fabricated and the discussion on the technological key-points has been reported, relating them to the physical requirements necessary for an efficient conversion mechanism. The preliminary results obtained at a lab-level are here discussed, indicating low electrical power output, but also how to increase the performance by solving the identified issues.

  2. Reproducibility of urinary bisphenol A concentrations measured during pregnancy in the Generation R Study.

    PubMed

    Jusko, Todd A; Shaw, Pamela A; Snijder, Claudia A; Pierik, Frank H; Koch, Holger M; Hauser, Russ; Jaddoe, Vincent W V; Burdorf, Alex; Hofman, Albert; Tiemeier, Henning; Longnecker, Matthew P

    2014-01-01

    The potential human health effects of bisphenol A (BPA) exposure are a public health concern. In order to design adequately powered epidemiological studies to address potential health effects, data on the reproducibility of BPA concentration in serial urine specimens taken during pregnancy are needed. To provide additional data on the reproducibility of maternal urine specimens, 80 women in the Generation R Study (Rotterdam, The Netherlands) contributed a spot urine specimen at <18, 18-25, and >25 weeks of pregnancy. Reproducibility, estimated by the intraclass correlation coefficient (ICC), was 0.32 (95% confidence interval: 0.18-0.46), and, on a creatinine basis, 0.31 (95% confidence interval: 0.16-0.47). Although the ICC observed in the Generation R Study is slightly higher than previous reproducibility studies of BPA, it nevertheless indicates a high degree of within-person variability that presents challenges for designing well-powered epidemiologic studies. PMID:24736100

  3. RESULTS OF ANALYTICAL SAMPLE CROSSCHECKS FOR NEXT GENERATION SOLVENT EXTRACTION SAMPLES ISOPAR L CONCENTRATION AND PH

    SciTech Connect

    Peters, T.; Fink, S.

    2011-09-29

    As part of the implementation process for the Next Generation Cesium Extraction Solvent (NGCS), SRNL and F/H Lab performed a series of analytical cross-checks to ensure that the components in the NGCS solvent system do not constitute an undue analytical challenge. For measurement of entrained Isopar{reg_sign} L in aqueous solutions, both labs performed similarly with results more reliable at higher concentrations (near 50 mg/L). Low bias occurred in both labs, as seen previously for comparable blind studies for the baseline solvent system. SRNL recommends consideration to use of Teflon{trademark} caps on all sample containers used for this purpose. For pH measurements, the labs showed reasonable agreement but considerable positive bias for dilute boric acid solutions. SRNL recommends consideration of using an alternate analytical method for qualification of boric acid concentrations.

  4. Conformational Dynamics in the Selectivity Filter of KcsA in Response to Potassium Ion Concentration

    PubMed Central

    Wylie, Benjamin J.; Tian, Lin; McDermott, Ann E.

    2010-01-01

    The conformational change in the selectivity filter of KcsA as a function of ambient potassium concentration is studied with solid state NMR. This highly conserved region of the protein is known to chelate potassium ions selectively. We report solid-state NMR chemical shift fingerprints of two distinct conformations of the selectivity filter; significant changes are observed in the chemical shifts of key residues in the filter as the buffer potassium ion concentration is changed from 50 mM to 1 µM. Potassium ion titration studies reveal that the site-specific Kd for K+ binding at the key pore residue Val 76, is on the order of ∼7 µM and that relatively high sample hydration is necessary to observe the low K+ conformer. Simultaneous detection of both conformers at low ambient potassium concentration suggests that the high K+ and low K+ states are in slow exchange on the NMR timescale (kex < 500 s−1). The slow rate and tight binding for evacuating both inner sites simultaneously, differ from prior observations in detergents in solution, but agree well with measurements by electrophysiology, and appear to result from our use of a hydrated bilayer environment. These characteristics rule out participation of the low K+ state on the timescale of ion transmission, which has been assumed to involve interchange of states where one of the inner binding sites is always occupied. On the other hand, these kinetic and thermodynamic characteristics of evacuation of the inner sites certainly could be compatible with participation in a control mechanism at low ion concentration, such as C-type inactivation, a process that is coupled to activation and involves closing of the outer mouth of the channel. PMID:20600123

  5. Concentration-mortality responses of Myzus persicae and natural enemies to selected insecticides.

    PubMed

    Bacci, Leandro; Rosado, Jander F; Picanço, Marcelo C; Pereira, Eliseu J G; Silva, Gerson A; Martins, Júlio C

    2012-01-01

    The toxicity of six insecticides was determined for the peach-potato aphid, Myzus persicae (Hemiptera: Aphididae), and some of its natural enemies - the predatory beetles Cycloneda sanguinea (Coccinellidae) and Acanthinus sp. (Anthicidae), and the wasp parasitoid Diaeretiella rapae (Aphidiidae). Natural enemies from these groups are important natural biological control agents in a number of agroecosystems, and insecticides potentially safe to these non-target organisms should be identified using standardized tests. Thus, concentration-mortality bioassays were carried out with both the aphid and its natural enemies to assess the toxicity and selectivity of acephate, deltamethrin, dimethoate, methamidophos, methyl parathion, and pirimicarb. The latter insecticide was highly selective to all natural enemies tested, and its LC(90) for M. persicae was 14-fold lower than the field rate recommended for control of the aphid in brassica crops. Methyl parathion also showed selectivity to C. sanguinea and Acanthinus sp., but not to D. rapae. Acephate was the least potent insecticide against M. persicae and was equally or more toxic to the natural enemies relative to the aphid. Pirimicarb and methyl parathion were efficient against M. persicae and selective in favor of two of the natural enemies tested. Acanthinus sp. and C. sanguinea were more tolerant to the insecticides than was the parasitoid D. rapae. This study shows that there are selective insecticides that may be compatible with conservation of natural enemies in brassica crops, which is important practical information to improve integrated pest management systems in these crops.

  6. The effects of selective serotonin reuptake inhibitors on platelet function in whole blood and platelet concentrates.

    PubMed

    Reikvam, Anne-Grete; Hustad, Steinar; Reikvam, Håkon; Apelseth, Torunn Oveland; Nepstad, Ina; Hervig, Tor Audun

    2012-01-01

    Several studies report that patients who are treated with selective serotonin reuptake inhibitors (SSRIs) for depression may have increased risk of bleeding, particularly from the gastrointestinal tract. This may be related to low intraplatelet serotonin concentrations. Several blood banks do not store platelets from donors using SSRIs for transfusion, although the possible effects of SSRIs on platelet storage are not documented. We conducted a case-control pilot study of apheresis platelet concentrates prepared from donors using SSRIs (n=8) and from donors without medication (n=10). The platelet concentrates were stored for 5 days. Light transmission aggregometry (LTA), thrombelastography (TEG), and flow cytometric analyses were preformed for in vitro measurements of platelet function. Platelet function and platelet serotonin content were investigated in whole blood and in platelet concentrates stored for up to 5 days. LTA, TEG, and flow cytometric analysis of glycoprotein expression did not reveal any significant differences between the two groups. All 18 platelet concentrates performed well according to the standards set for platelet quality in relation to transfusion. Blood donors using SSRIs had significantly lower platelet serotonin compared to blood donors without medication. The results from our pilot study indicate that platelets from donors using SSRIs may be suitable for transfusion after storage for 5 days, but further laboratory and clinical studies are necessary to confirm this.

  7. First-generation students’ underperformance at university: the impact of the function of selection

    PubMed Central

    Jury, Mickaël; Smeding, Annique; Darnon, Céline

    2015-01-01

    According to recent research, university not only has the role to educate and train students, it also has the role to select the best students. We argue that this function of selection disadvantages first-generation students, in comparison with continuing-generation students. Thus, the mere activation of the function of selection should be sufficient to produce achievement differences between first-generation and continuing-generation students in a novel academic task. Furthermore, we propose that when the function of selection is salient, first-generation students would be more vigilant to a cue that may confirm their inferiority, which should explain their underperformance. In the present experiment, participants were asked to complete an arithmetic modular task under two conditions, which either made the function of selection salient or reduced its importance. Participants’ vigilance to a threatening cue (i.e., their performance relative to others) was measured through an eye-tracking technique. The results confirmed that first-generation students performed more poorly compared to continuing-generation students only when the function of selection was salient while no differences appeared in the no-selection condition. Regarding vigilance, the results did not confirm our hypothesis; thus, mediation path could not be tested. However, results indicated that at a high level of initial performance, first-generation students looked more often at the threatening cue. In others words, these students seemed more concerned about whether they were performing more poorly than others compared to their continuing-generation counterparts. Some methodological issues are discussed, notably regarding the measure of vigilance. PMID:26074854

  8. Investigation into the Effect of Concentration of Benzotriazole on the Selective Layer Surface in the Chemical Mechanical Planarization Process

    NASA Astrophysics Data System (ADS)

    Ilie, Filip; Laurian, Tiberiu

    2015-12-01

    During selective layer chemical mechanical planarization (CMP), the surface layer is selectively oxidized and removed. Material removal rate in selective layer CMP depends on the depth of removal, pH of the solution, slurry chemistry, potential, percentage of oxidizer, and the applied load. Benzotriazole (BTA) has been used as a corrosion inhibitor in the CMP process. The role of BTA is to prevent corrosion of a pattern via a chemical reaction that forms a Cu-BTA passive film on the selective-layer surface. This paper focuses on the concentration effect of BTA in the slurry of a selective layer CMP process by measuring the friction force during CMP and the modification of the selective layer films immersed in slurries containing various concentrations of BTA. Additionally; the friction characteristics with the concentration of BTA in the selective layer CMP slurry. The effect of BTA concentration was verified using an empirical model based on the friction energy ( E f).

  9. Selective Precipitation and Concentrating of Perovskite Crystals from Titanium-Bearing Slag Melt in Supergravity Field

    NASA Astrophysics Data System (ADS)

    Gao, Jintao; Zhong, Yiwei; Guo, Zhancheng

    2016-08-01

    Selective precipitation and concentrating of perovskite crystals from titanium-bearing slag melt in the supergravity field was investigated in this study. Since perovskite was the first precipitated phase from the slag melt during the cooling process, and a greater precipitation quantity and larger crystal sizes of perovskite were obtained at 1593 K to 1563 K (1320 °C to 1290 °C), concentrating of perovskite crystals from the slag melt was carried out at this temperature range in the supergravity field, at which the perovskite transforms into solid particles while the other minerals remain in the liquid melt. The layered structures appeared significantly in the sample obtained by supergravity treatment, and all the perovskite crystals moved along the supergravity direction and concentrated as the perovskite-rich phase in the bottom area, whereas the molten slag concentrated in the upper area along the opposite direction, in which it was impossible to find any perovskite crystals. With the gravity coefficient of G = 750, the mass fraction of TiO2 in the perovskite-rich phase was up to 34.65 wt pct, whereas that of the slag phase was decreased to 12.23 wt pct, and the recovery ratio of Ti in the perovskite-rich phase was up to 75.28 pct. On this basis, an amplification experimental centrifugal apparatus was exploited and the continuous experiment with larger scale was further carried out, the results confirming that selective precipitation and concentrating of perovskite crystals from the titanium-bearing slag melt by supergravity was a feasible method.

  10. A Different World: African American, First Generation College Women at a Selective University

    ERIC Educational Resources Information Center

    Johnson, Jennifer Michelle

    2013-01-01

    The purpose of this study was to gain a better understanding of the academic and social experiences of African American, first generation college students attending a selective university. Following interpretive case study methodology, the major research questions guiding this study were: How do African American, first generation college students…

  11. Projects, Training, and Strategies for Generating Income: A Selected Annotated Bibliography. Annotated Bibliography #4.

    ERIC Educational Resources Information Center

    Michigan State Univ., East Lansing. Non-Formal Education Information Center.

    A selected annotated bibliography on projects, training, and strategies for generating income, intended for persons actively engaged in non-formal education for development, reflects a growing number of projects on income generation by and for women's groups, and a reliance upon indigenous associations and group action. Documents dating from 1969…

  12. COMPREHENSIVE ANALYSIS OF BIOLOGICALLY RELEVANT ARSENICALS BY PH-SELECTIVE HYDRIDE GENERATION-ATOMIC ABSORPTION SPECTROMETRY

    EPA Science Inventory


    A method based on pH-selective generation and separation of arsines is commonly used for analysis of inorganic, methylated, and dimethylated trivalent and pentavalent arsenicals by hydride generation-atomic absorption spectrometry (HG-AAS). We have optimized this method to pe...

  13. Influence of scandium concentration on power generation figure of merit of scandium aluminum nitride thin films

    SciTech Connect

    Akiyama, Morito; Nagase, Toshimi; Umeda, Keiichi; Honda, Atsushi

    2013-01-14

    The authors have investigated the influence of scandium concentration on the power generation figure of merit (FOM) of scandium aluminum nitride (Sc{sub x}Al{sub 1-x}N) films prepared by cosputtering. The power generation FOM strongly depends on the scandium concentration. The FOM of Sc{sub 0.41}Al{sub 0.59}N film was 67 GPa, indicating that the FOM is five times larger than that of AlN. The FOM of Sc{sub 0.41}Al{sub 0.59}N film is higher than those of lead zirconate titanate and Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} films, which is the highest reported for any piezoelectric thin films. The high FOM of Sc{sub 0.41}Al{sub 0.59}N film is due to the high d{sub 31} and the low relative permittivity.

  14. Code to generate random identifiers and select QA/QC samples

    USGS Publications Warehouse

    Mehnert, Edward

    1992-01-01

    SAMPLID is a PC-based, FORTRAN-77 code which generates unique numbers for identification of samples, selection of QA/QC samples, and generation of labels. These procedures are tedious, but using a computer code such as SAMPLID can increase efficiency and reduce or eliminate errors and bias. The algorithm, used in SAMPLID, for generation of pseudorandom numbers is free of statistical flaws present in commonly available algorithms.

  15. Gender, Race, and the College Science Track: Analyzing Field Concentrations and Institutional Selectivity

    NASA Astrophysics Data System (ADS)

    Mullen, Ann L.

    This study examines the effects of gender, race, and ethnicity on the pursuit of scientific fields of study among college students. It builds on previous research by considering variation among fields of science and variation across institutions in selectivity. The findings reveal that African American students graduating with degrees in science are underrepresented in elite institutions, principally because of their concentration in historically Black colleges and universities. The evidence does not indicate that female science majors are underrepresented in elite institutions. Both groups are concentrated among the science fields with the lowest labor market returns. These findings demonstrate that female and minority students are more disadvantaged than studies of their simple representation in science would suggest.

  16. Ambient airborne [sup 222]Rn concentrations at selected Hanford Site facilities

    SciTech Connect

    Atencio, E.M.; Gleckler, B.P.; Smith, C.Y.

    1993-01-01

    Summary of ambient airborne [sup 222]Rn concentrations measured at selected US Department of Energy Hanford Site facilities located in southeastern Washington. Measurements were made using a 3 [times] 3 sodium-iodide gamma spectroscopy counting system, and then quantified using verified and validated computer software. Over the last 2 years, eight Hanford Site facilities were thoroughly characterized, the results are presented. The facilities characterized in response to the Indoor Radon Abatement Act, Public Law 100--551. Results from test samples reveal relatively low levels of airborne radon.

  17. Ambient airborne {sup 222}Rn concentrations at selected Hanford Site facilities

    SciTech Connect

    Atencio, E.M.; Gleckler, B.P.; Smith, C.Y.

    1993-01-01

    Summary of ambient airborne {sup 222}Rn concentrations measured at selected US Department of Energy Hanford Site facilities located in southeastern Washington. Measurements were made using a 3 {times} 3 sodium-iodide gamma spectroscopy counting system, and then quantified using verified and validated computer software. Over the last 2 years, eight Hanford Site facilities were thoroughly characterized, the results are presented. The facilities characterized in response to the Indoor Radon Abatement Act, Public Law 100--551. Results from test samples reveal relatively low levels of airborne radon.

  18. Concentrations and risk assessment of selected monoaromatic hydrocarbons in buses and bus stations of Hangzhou, China.

    PubMed

    Li, Shuang; Chen, Shuguang; Zhu, Lizhong; Chen, Xiasheng; Yao, Chaoying; Shen, Xueyou

    2009-03-01

    Air pollution surveys of ten selected monoaromatic hydrocarbons (MAHCs) were conducted in buses and bus stations in Hangzhou, China. The mean concentrations of MAHCs in the air of buses and bus stations were 95.9 and 36.5 microg/m(3), respectively, of which toluene was the highest in all the sampling sites. Mean concentrations of all MAHCs in buses were statistically higher than those nearby bus stations (p<0.05). MAHCs concentrations in buses largely depend on vehicle conditions (including vehicle type, fuel type, interior decoration, etc.) and traffic conditions (mainly traffic density). Among the investigated buses, microbuses had the highest MAHCs level, while electric buses had the lowest. Buses driven in downtown had the highest MAHCs level, followed by those in suburban areas and tourist areas. The mean concentration ratio of toluene to benzene was 2.1+/-0.9, indicating that vehicle emission was the dominant source of MAHCs. Interior decorations, such as painting and surface coating, could also contribute to the MAHCs in the buses. The mean lifetime carcinogenic risks for passengers and bus drivers were 1.11x10(-5) and 4.00x10(-5), respectively, which were way above the limit set by USEPA. The health risk caused by MAHCs in bus microenvironment should be cautioned.

  19. Comparison of predicted and measured concentrations of selected pharmaceuticals, fragrances and hormones in Spanish sewage.

    PubMed

    Carballa, Marta; Omil, Francisco; Lema, Juan M

    2008-07-01

    A review of consumption and excretion rates of 17 pharmaceuticals, two musk fragrances and two hormones by the Spanish population in 2003 was performed. For that purpose, three different models were used: (i) extrapolation of the per capita use in Europe to the number of inhabitants of Spain for musk fragrances; (ii) annual prescription items multiplied by the average daily dose for pharmaceuticals and; (iii) excretion rates of different groups of population for hormones. This information enabled the prediction of the expected concentrations (PEC) entering sewage treatment plants (STPs), which were subsequently compared with the measured environmental concentrations (MEC) in raw sewage. Annual drugs consumption in Spain ranges from few kilograms (Oxazepam and 17alpha-ethinylestradiol) to several hundred of tons (Ibuprofen). The quantities of musks used accounts for 110-450 kg d(-1) and the total amount of hormones excreted daily reaches almost 1 kg d(-1). 12 out of 21 selected substances were predicted to be present in raw sewage influent at concentrations greater than 100 ng l(-1) and these predicted concentrations fitted with the measured values for half of them (Carbamazepine, Diazepam, Ibuprofen, Naproxen, Diclofenac, Sulfamethoxazole, Roxithromycin, Erythromycin and 17alpha-ethinylestradiol).

  20. Electrochemical scaffold generates localized, low concentration of hydrogen peroxide that inhibits bacterial pathogens and biofilms.

    PubMed

    Sultana, Sujala T; Atci, Erhan; Babauta, Jerome T; Falghoush, Azeza Mohamed; Snekvik, Kevin R; Call, Douglas R; Beyenal, Haluk

    2015-01-01

    We hypothesized that low concentrations of H2O2 could be generated through the electrochemical conversion of oxygen by applying an electric potential to a conductive scaffold and produce a low, but constant, concentration of H2O2 that would be sufficient to destroy biofilms. To test our hypothesis we used a multidrug-resistant Acinetobacter baumannii strain, because this species is often implicated in difficult-to-treat biofilm infections. We used conductive carbon fabric as the scaffold material ("e-scaffold"). In vitro experiments demonstrated the production of a maximum constant concentration of ~25 μM H2O2 near the e-scaffold surface. An e-scaffold was overlaid onto an existing A. baumannii biofilm, and within 24 h there was a ~4-log reduction in viable bacteria with an ~80% decrease in biofilm surface coverage. A similar procedure was used to overlay an e-scaffold onto an existing A. baumannii biofilm that was grown on a porcine explant. After 24 h, there was a ~3-log reduction in viable bacteria from the infected porcine explants with no observable damage to the underlying mammalian tissue based on a viability assay and histology. This research establishes a novel foundation for an alternative antibiotic-free wound dressing to eliminate biofilms.

  1. Electrochemical scaffold generates localized, low concentration of hydrogen peroxide that inhibits bacterial pathogens and biofilms

    PubMed Central

    Sultana, Sujala T.; Atci, Erhan; Babauta, Jerome T.; Mohamed Falghoush, Azeza; Snekvik, Kevin R.; Call, Douglas R.; Beyenal, Haluk

    2015-01-01

    We hypothesized that low concentrations of H2O2 could be generated through the electrochemical conversion of oxygen by applying an electric potential to a conductive scaffold and produce a low, but constant, concentration of H2O2 that would be sufficient to destroy biofilms. To test our hypothesis we used a multidrug-resistant Acinetobacter baumannii strain, because this species is often implicated in difficult-to-treat biofilm infections. We used conductive carbon fabric as the scaffold material (“e-scaffold”). In vitro experiments demonstrated the production of a maximum constant concentration of ~25 μM H2O2 near the e-scaffold surface. An e-scaffold was overlaid onto an existing A. baumannii biofilm, and within 24 h there was a ~4-log reduction in viable bacteria with an ~80% decrease in biofilm surface coverage. A similar procedure was used to overlay an e-scaffold onto an existing A. baumannii biofilm that was grown on a porcine explant. After 24 h, there was a ~3-log reduction in viable bacteria from the infected porcine explants with no observable damage to the underlying mammalian tissue based on a viability assay and histology. This research establishes a novel foundation for an alternative antibiotic-free wound dressing to eliminate biofilms. PMID:26464174

  2. Selecting reference concentrations for fish biliary PAH metabolites for stream ecological exposure assessment

    SciTech Connect

    Lin, E.L.C.; Cormier, S.M.; Subramanian, B.; Williams, D.; Wulfeck, K.; Detmer, S.; Lowry, M.E.

    1995-12-31

    Reference concentrations for two types of biliary polycyclic aromatic hydrocarbon (PAH) metabolites were empirically determined for two species of fish. Bile from white sucker and common carp were collected from streams in Ohio having poor to excellent conditions based on a modified index of biotic integrity (mIBI). PAH were measured using fixed wavelength fluorescence with excitation/emission pairs at 290/335 nm for naphthalene-type (NAPH) and 380/430 nm for benzo[a]pyrene-type (B[a]P) metabolites. Exposures to PAH`s were estimated for petroleum sources with NAPH and from combustion sources with B[a]P. Three criteria were used to select reference concentrations. Site criteria were: an mIBI score of at least 30; relatively low median values of biliary PAH concentration; and low statistical variation. The median reference values selected were 0.5 {micro}g B[a]P/mg protein and 50 {micro}g NAPH/mg protein for white suckers and 0.5 {micro}g B[a]P/mg protein and 90 {micro}g NAPH/mg protein for common carp. Of the 28 sites sampled with white sucker in 1993, 68% exceeded the reference value for NAPH and 32% for B[a]P. Of the 22 sites sampled with carp, 68% exceeded the value for NAPH and 41% for B[a]P. Likewise, more sites with mIBI scores between 30 and 60 exceeded the NAPH reference than the B[a]P reference concentration.

  3. Extending the life of a 99Tcm generator: a simple and convenient method for concentrating generator eluate for clinical use.

    PubMed

    Blower, P J

    1993-11-01

    99Tcm-pertechnetate can conveniently be concentrated 5-20-fold by passing up to 20 ml through a sequence of two (or three) disposable columns, one (or two) to remove chloride and one to concentrate the pertechnetate for subsequent elution with a small volume of saline. This procedure is useful for utilizing eluates with low radioactive concentration in applications that require high radioactive concentration.

  4. State test-anxiety, selective attention and concentration in university students.

    PubMed

    Fernández-Castillo, Antonio; Caurcel, María J

    2015-08-01

    The principal aim of this study was to assess the level of selective attention and mental concentration before exams in a sample of university students and to determine a possible relationship between anxiety and reduction of levels of attention in this circumstance. A total of 403 university students, 176 men and 227 women, aged from 18 to 46 years, participated in the study. Of them, 169 were first-year undergraduates, 118 were second to fourth-year undergraduates and 116 were postgraduate Master's degree students. All of them completed the Spanish version of the Spielberger State-Anxiety Inventory and the D2 Attention Test just before taking an exam. Our results showed that participants with lower levels of anxiety had higher levels of selective attention and mental concentration before the exam. These results specifically indicate that when anxiety levels are very high, this could over-activate the orientating and alerting functions and to reduce the capacity of attentional control. These processes could have a negative impact on specific attentional processes and become a negative influence on performance in exams.

  5. State test-anxiety, selective attention and concentration in university students.

    PubMed

    Fernández-Castillo, Antonio; Caurcel, María J

    2015-08-01

    The principal aim of this study was to assess the level of selective attention and mental concentration before exams in a sample of university students and to determine a possible relationship between anxiety and reduction of levels of attention in this circumstance. A total of 403 university students, 176 men and 227 women, aged from 18 to 46 years, participated in the study. Of them, 169 were first-year undergraduates, 118 were second to fourth-year undergraduates and 116 were postgraduate Master's degree students. All of them completed the Spanish version of the Spielberger State-Anxiety Inventory and the D2 Attention Test just before taking an exam. Our results showed that participants with lower levels of anxiety had higher levels of selective attention and mental concentration before the exam. These results specifically indicate that when anxiety levels are very high, this could over-activate the orientating and alerting functions and to reduce the capacity of attentional control. These processes could have a negative impact on specific attentional processes and become a negative influence on performance in exams. PMID:25104475

  6. Changes in concentration levels of selected VOCs in newly erected and remodelled building in Gdansk.

    PubMed

    Zabiegała, B; Namieśnik, J; Przyk, E; Przyjazny, A

    1999-11-01

    Volatile organic compounds such as benzene, toluene, butyl acetate, ethylbenzene, m-xylene, styrene and m-dichlorobenzene were measured in three newly erected and remodelled dwellings. The present study also attempted to examine the time dependence of concentrations of selected VOCs in each investigated dwelling. This was accomplished by at least triplicate measurements of the IAQ. To collect a series of air samples the active and passive methods were used. In both cases activated charcoal was applied as a sorption medium. The samples were recovered by solvent extraction, and analysed by capillary column gas chromatography, employing a flame ionisation detector. The experimental results showed that MAC values for analysed VOCs were exceeded (even a few orders of magnitude) for the measurements made before inhabiting of the occupants, in every investigated dwelling. The concentrations of the investigated VOCs decreased significantly with time, which should be expected, although in some cases the levels of selected VOCs remained still high. Our experience indicates that parallel application of two different indoor air sampling techniques to determine analytes of interest, though more laborious and time consuming, can lead to significant conclusions concerning indoor air quality in monitored spaces. PMID:10576105

  7. Determinants of health concentration selection among University of Southern California MSW students.

    PubMed

    Mitchell, Keyon R; Joosten, Dawn Marie

    2014-11-01

    By 2020, health care social workers are projected to make up 25 percent of the entire number of professional social workers in the United States. At the University of Southern California, the number of graduate students selecting the health social work concentration has increased exponentially over the last five years. Although there are no published findings to indicate that other schools of social work are experiencing a similar trend, the Bureau of Labor Statistics has reported that, nationally, the number of social workers employed in health care has increased and is projected to continue increasing over the next decade. The purpose of this study was to identify decision-making determinants of MSW students pursuing a specific vocational interest in health care settings. The study used a questionnaire to gather quantitative and qualitative data from a population of MSW students. The findings suggest that graduate students select the health concentration based on self-knowledge (abilities and interests) and vocational knowledge (job demands and labor market). This article concludes with a discussion of the implications of these findings for health social work curriculums, practice, research, policy, and the integral role social workers play in health care reform in the present and will play in the future.

  8. Photovoltaic manufacturing technology (PVMaT) improvements for ENTECH{close_quote}s fourth-generation concentrator systems

    SciTech Connect

    ONeill, M.J.; McDanal, A.J.

    1997-02-01

    This paper describes recent improvements in manufacturing technology for fourth-generation photovoltaic concentrator systems. The fourth-generation systems are firmly based on prior generations of a field-proven, high-efficiency, stable photovoltaic technology. The fourth-generation manufacturing process has been streamlined and validated through pilot runs and field deployments. Future plans include a 1.5 MW installation in 1998, as part of the Solar Enterprise Zone (SEZ) program in Nevada. {copyright} {ital 1997 American Institute of Physics.}

  9. Structural basis of nucleoside and nucleoside drug selectivity by concentrative nucleoside transporters

    PubMed Central

    Johnson, Zachary Lee; Lee, Jun-Ho; Lee, Kiyoun; Lee, Minhee; Kwon, Do-Yeon; Hong, Jiyong; Lee, Seok-Yong

    2014-01-01

    Concentrative nucleoside transporters (CNTs) are responsible for cellular entry of nucleosides, which serve as precursors to nucleic acids and act as signaling molecules. CNTs also play a crucial role in the uptake of nucleoside-derived drugs, including anticancer and antiviral agents. Understanding how CNTs recognize and import their substrates could not only lead to a better understanding of nucleoside-related biological processes but also the design of nucleoside-derived drugs that can better reach their targets. Here, we present a combination of X-ray crystallographic and equilibrium-binding studies probing the molecular origins of nucleoside and nucleoside drug selectivity of a CNT from Vibrio cholerae. We then used this information in chemically modifying an anticancer drug so that it is better transported by and selective for a single human CNT subtype. This work provides proof of principle for utilizing transporter structural and functional information for the design of compounds that enter cells more efficiently and selectively. DOI: http://dx.doi.org/10.7554/eLife.03604.001 PMID:25082345

  10. Free radical generation and concentration in a plasma polymer: the effect of aromaticity.

    PubMed

    Ershov, Sergey; Khelifa, Farid; Lemaur, Vincent; Cornil, Jérôme; Cossement, Damien; Habibi, Youssef; Dubois, Philippe; Snyders, Rony

    2014-08-13

    Plasma polymer films (PPF) have increasing applications in many fields due to the unique combination of properties of this class of materials. Among notable features arising from the specifics of plasma polymerization synthesis, a high surface reactivity can be advantageously used when exploited carefully. It is related to the presence of free radicals generated during the deposition process through manifold molecular bond scissions in the energetic plasma environment. In ambient atmosphere, these radicals undergo autoxidation reactions resulting in undesired polymer aging. However, when the reactivity of surface radicals is preserved and they are put in direct contact with a chemical group of interest, a specific surface functionalization or grafting of polymeric chains can be achieved. Therefore, the control of the surface free radical density of a plasma polymer is crucially important for a successful grafting. The present investigation focuses on the influence of the hydrocarbon precursor type, aromatic vs aliphatic, on the generation and concentration of free radicals on the surface of the PPF. Benzene and cyclohexane were chosen as model precursors. First, in situ FTIR analysis of the plasma phase supplemented by density functional theory calculations allowed the main fragmentation routes of precursor molecules in the discharge to be identified as a function of energy input. Using nitric oxide (NO) chemical labeling in combination with X-ray photoelectron spectroscopy analysis, a quantitative evaluation of concentration of surface free radicals as a function of input power has been assessed for both precursors. Different evolutions of the surface free radical density for the benzene- and cyclohexane-based PPF, namely, a continuous increase versus stabilization to a plateau, are attributed to different plasma polymerization mechanisms and resulting structures as illustrated by PPF characterization findings. The control of surface free radical density can be

  11. Selective trapping and concentration of nanoparticles and viruses in dual-height nanofluidic channels.

    PubMed

    Hamblin, Mark N; Xuan, Jie; Maynes, Daniel; Tolley, H Dennis; Belnap, David M; Woolley, Adam T; Lee, Milton L; Hawkins, Aaron R

    2010-01-21

    Nanofluidic systems offer advantages for chemical analysis, including small sample volumes, size-selective particle trapping, sample concentration and the ability to separate and detect single molecules. Such systems can be fabricated using planar nanochannels, which rely on standard photolithographic techniques. Nanochannel fluid flow can be driven by capillary action, which benefits from simple injection and reasonably high flow rates. We demonstrate an analysis chip fabricated with planar nanochannels that consist of two adjoining segments of different heights. When nano-analytes elute through the channel, they become physically trapped when the channel dimensions shrink below the size of the particles. We demonstrate the capability of these devices to trap and concentrate by using the following: 120-nm polymer beads, 30-nm polymer beads, Herpes simplex virus 1 capsids, and hepatitis B virus capsids. Each species was fluorescently labeled and its resulting fluorescent signal was detected using a cooled CCD camera. We show how the signal-to-noise ratio of trapped analyte intensity varies linearly with analyte concentration. The goal of this work is to eventually perform size-based fractionation of a variety of nanoparticles, including biomolecules such as proteins.

  12. Concentrations of Mineral in Amniotic Fluid and Their Relations to Selected Maternal and Fetal Parameters.

    PubMed

    Suliburska, J; Kocyłowski, R; Komorowicz, I; Grzesiak, M; Bogdański, P; Barałkiewicz, D

    2016-07-01

    The concentrations of various trace elements in amniotic fluid (AF) change over the course of pregnancy, with gestational age and fetus growth. The aim of the present study was to evaluate the concentrations of selected essential and toxic elements in AF and their relations to maternal and fetal parameters. The study was carried out in 39 pregnant women, aged 34.6 ± 4.7 years, between weeks 16 and 26 of gestation. Amniotic fluid samples were obtained during the standard procedure of amniocentesis in high-risk patients for chromosomal abnormalities. An inductively coupled plasma mass spectrometry (ICP-MS) technique was used to determine the levels of Al, As, Ba, Cd, Co, Cr, Cu, Mg, Mn, Ni, Sr, U, and V in AF. Body mass and blood pressure were measured in all the women. The basic parameters of fetal development were also assayed. It was found that the age of the mother, the gender of the fetus, and the week of the pregnancy may affect the concentrations of mineral in the amniotic fluid. Moreover, several significant correlations between the essential and toxic elements and maternal and fetal parameters were observed. In particular, negative and positive correlations between fetal parameters and magnesium and copper levels in AF, respectively, were seen. The present findings demonstrate the association between minerals in AF and fetal development.

  13. Concentration of Selected Metals in Whole Blood, Plasma, and Urine in Short Stature and Healthy Children.

    PubMed

    Klatka, Maria; Błażewicz, Anna; Partyka, Małgorzata; Kołłątaj, Witold; Zienkiewicz, Ewa; Kocjan, Ryszard

    2015-08-01

    The short stature in children is defined as height below the third percentile from the mean for age and gender. This problem affects about 3% of young people. More than 20,000 children in Poland have problems with short stature. There is not much information available in the literature on the study of metals in blood, plasma, and urine in children with short stature. The study was conducted on a group of 56 short stature Polish children and 35 healthy children. The content of metals was determined using high-performance ion chromatography and inductively coupled plasma mass spectrometry methods. The study revealed significant differences between the content of selected metals in body fluids between a short stature group and healthy children. There were significant differences in the Fe, Cu, and Ni concentrations between the groups with respect to the hormonal therapy. There were no significant differences between the groups with respect to the area where the children lived. The results showed no statistically significant differences between metal concentration and age, body weight, and height. The study demonstrated statistically significant differences between the content of metals in body fluids in short stature children compared with the healthy children. It seems that the difference in the concentration of certain elements may also be the result of growth hormone therapy and the interaction between various metals. Both the alterations in the content of metals and their mutual interactions may play an important role in the pathogenesis of short stature children.

  14. Dimethyl sulfoxide at high concentrations inhibits non-selective cation channels in human erythrocytes.

    PubMed

    Nardid, Oleg A; Schetinskey, Miroslav I; Kucherenko, Yuliya V

    2013-03-01

    Dimethyl sulfoxide (DMSO), a by-product of the pulping industry, is widely used in biological research, cryobiology and medicine. On cellular level DMSO was shown to suppress NMDA-AMPA channels activation, blocks Na+ channel activation and attenuates Ca2+ influx (Lu and Mattson 2001). In the present study we explored the whole-cell patch-clamp to examine the acute effect of high concentrations of DMSO (0.1-2 mol/l) on cation channels activity in human erythrocytes. Acute application of DMSO (0.1-2 mol/l) dissolved in Cl--containing saline buffer solution significantly inhibited cation conductance in human erythrocytes. Inhibition was concentration-dependent and had an exponential decay profile. DMSO (2 mol/l) induced cation inhibition in Cl-- containing saline solutions of: 40.3 ± 3.9% for K+, 35.4 ± 3.1% for Ca2+ and 47.4 ± 1.9% for NMDG+. Substitution of Cl- with gluconate- increased the inhibitory effect of DMSO on the Na+ current. Inhibitory effect of DMSO was neither due to high permeability of erythrocytes to DMSO nor to an increased tonicity of the bath media since no effect was observed in 2 mol/l glycerol solution. In conclusion, we have shown that high concentrations of DMSO inhibit the non-selective cation channels in human erythrocytes and thus protect the cells against Na+ and Ca2+ overload. Possible mechanisms of DMSO effect on cation conductance are discussed. PMID:23531832

  15. Genome-wide single-generation signatures of local selection in the panmictic European eel.

    PubMed

    Pujolar, J M; Jacobsen, M W; Als, T D; Frydenberg, J; Munch, K; Jónsson, B; Jian, J B; Cheng, L; Maes, G E; Bernatchez, L; Hansen, M M

    2014-05-01

    Next-generation sequencing and the collection of genome-wide data allow identifying adaptive variation and footprints of directional selection. Using a large SNP data set from 259 RAD-sequenced European eel individuals (glass eels) from eight locations between 34 and 64(o) N, we examined the patterns of genome-wide genetic diversity across locations. We tested for local selection by searching for increased population differentiation using F(ST) -based outlier tests and by testing for significant associations between allele frequencies and environmental variables. The overall low genetic differentiation found (F(ST) = 0.0007) indicates that most of the genome is homogenized by gene flow, providing further evidence for genomic panmixia in the European eel. The lack of genetic substructuring was consistent at both nuclear and mitochondrial SNPs. Using an extensive number of diagnostic SNPs, results showed a low occurrence of hybrids between European and American eel, mainly limited to Iceland (5.9%), although individuals with signatures of introgression several generations back in time were found in mainland Europe. Despite panmixia, a small set of SNPs showed high genetic differentiation consistent with single-generation signatures of spatially varying selection acting on glass eels. After screening 50 354 SNPs, a total of 754 potentially locally selected SNPs were identified. Candidate genes for local selection constituted a wide array of functions, including calcium signalling, neuroactive ligand-receptor interaction and circadian rhythm. Remarkably, one of the candidate genes identified is PERIOD, possibly related to differences in local photoperiod associated with the >30° difference in latitude between locations. Genes under selection were spread across the genome, and there were no large regions of increased differentiation as expected when selection occurs within just a single generation due to panmixia. This supports the conclusion that most of the genome is

  16. Experimental studies with selected light sources for NIRS of brain tissue: quantifying tissue chromophore concentration

    NASA Astrophysics Data System (ADS)

    Myllylä, Teemu; Korhonen, Vesa; Kiviniemi, Vesa; Tuchin, Valery

    2015-03-01

    Near-infrared spectroscopy (NIRS) based techniques are utilised in quantifying changes of chromophore concentrations in tissue. Particularly, non-invasive in vivo measurements of tissue oxygenation in the cerebral cortex are of interest. The measurement method is based on illuminating tissue and measuring the back-scattered light at wavelengths of interest. Tissue illumination can be realised using different techniques and various light sources. Commonly, lasers and laser diodes (LD) are utilised, but also high-power light emitting diodes (HPLED) are becoming more common. At the moment, a wide range of available narrow-band light sources exists, covering basically the entire spectrum of interest in brain tissue NIRS measurements. In this paper, in the centre of our interest are LDs and HPLEDs, because of their affordability, efficiency in terms of radiant flux versus size and easiness to adopt in in vivo medical applications. We compare characteristics of LDs and HPLEDs at specific wavelengths and their suitability for in vivo quantifying of different tissue chromophore concentration, particularly in cerebral blood flow (CBF). A special focus is on shape and width of the wavelength bands of interest, generated by the LDs and HPLEDs. Moreover, we experimentally study such effects as, spectroscopy cross talk, separability and signal-to-noise ratio (SNR) when quantifying tissue chromophore concentration. Chromophores of our interest are cytochrome, haemoglobin and water. Various LDs and HPLEDs, producing narrow-band wavelengths in the range from 500 nm to 1000 nm are tested.

  17. Miniaturized Antimicrobial Susceptibility Test by Combining Concentration Gradient Generation and Rapid Cell Culturing

    PubMed Central

    Kim, Samuel C.; Cestellos-Blanco, Stefano; Inoue, Keisuke; Zare, Richard N.

    2015-01-01

    Effective treatment of bacterial infection relies on timely diagnosis and proper prescription of antibiotic drugs. The antimicrobial susceptibility test (AST) is one of the most crucial experimental procedures, providing the baseline information for choosing effective antibiotic agents and their dosages. Conventional methods, however, require long incubation times or significant instrumentation costs to obtain test results. We propose a lab-on-a-chip approach to perform AST in a simple, economic, and rapid manner. Our assay platform miniaturizes the standard broth microdilution method on a microfluidic device (20 × 20 mm) that generates an antibiotic concentration gradient and delivers antibiotic-containing culture media to eight 30-nL chambers for cell culture. When tested with 20 μL samples of a model bacterial strain (E. coli ATCC 25922) treated with ampicillin or streptomycin, our method allows for the determination of minimum inhibitory concentrations consistent with the microdilution test in three hours, which is almost a factor of ten more rapid than the standard method. PMID:27025635

  18. Chemical inhibitors of CYP450 enzymes in liver microsomes: combining selectivity and unbound fractions to guide selection of appropriate concentration in phenotyping assays.

    PubMed

    Nirogi, Ramakrishna; Palacharla, Raghava Choudary; Uthukam, Venkatesham; Manoharan, Arunkumar; Srikakolapu, Surya Rao; Kalaikadhiban, Ilayaraja; Boggavarapu, Rajesh Kumar; Ponnamaneni, Ranjith Kumar; Ajjala, Devender Reddy; Bhyrapuneni, Gopinadh

    2015-02-01

    1. Chemical inhibition is the widely used method in reaction phenotyping assays for estimation of specific enzyme contribution to a given metabolic pathway. The results from phenotyping assays depend on the selectivity of chemical inhibitor and the concentration of inhibitor used in the incubation. 2. The higher protein concentrations used in the in vitro phenotyping assays will impact the inhibitory potency of chemical inhibitors. The objective of the study is to evaluate comprehensively the selectivity of chemical inhibitors and to guide in selecting appropriate concentration of the chemical inhibitors to be used in the phenotyping assays based on unbound fractions. 3. Selectivity of chemical inhibitors against nine major CYP450 isoforms was determined in liver microsomes using standard probe substrates. The unbound fractions of the selective inhibitors were determined in human liver microsomes using high-throughput equilibrium dialysis. Combining unbound inhibitor concentrations that are required to inhibit the CYP450 activities by 90% and unbound fractions of the chemical inhibitors in liver microsomes appropriate total concentrations of the inhibitors to be used in the phenotyping assays were reported. 4. The findings suggest that non-specific binding of the chemical inhibitors need to be taken into account while selecting concentrations for phenotyping assays.

  19. Stationary Optical Concentrator Designs and Wafer Scale Monolithic Integration of Semiconductor Devices for Next Generation Photovoltaic Panels

    NASA Astrophysics Data System (ADS)

    Kim, Jung Min

    A major barrier in utilizing solar energy for large scale deployment is the cost of the photovoltaic (PV) systems. Several approaches have been used for the cost reduction such as by modifying PV system designs in addition to enhancing the efficiency of solar cells. Due to the high cost of materials, minimizing the use of solar cells such as in concentrator type systems is highly attractive for reducing the cost of the PV modules by focusing the incident light onto the PV cell. However concentrator PV systems (CPV) require constant tracking of the sun and hence are complex in design and expensive to operate, except in limited situations such as large scale PV power plants. It is desirable to design new concentrator type systems that do not require continuous tracking of the sun. These systems could ultimately reduce the PV system cost to a minimum while maximizing the power conversion efficiency. In this thesis we propose a simple design for a stationary concentrator photovoltaic (SCPV) system that could significantly reduce the cost of generating electricity using PV devices. Using optical ray tracing simulations, we have been able to design SCPV systems that could reduce the PV module cost by 2--10 times without compromising on the power conversion efficiency of the system. Another alternative approach for sustainable high efficiency PV system design is to develop low cost PV cells for terrestrial applications. To meet the demands of low cost and large scale production, larger and thinner (or flexible) substrates are required. We demonstrated the feasibility of fabricating monolithic interconnected PV devices at the wafer scale (2 inch wafers). In this study, GaSb PV cells grown on semi-insulating GaAs were used as the model material. Crucial device fabrication steps such as a selective etching process have been developed that is necessary for isolating individual devices on the wafer and interconnecting them with sub-micron scale accuracy. Selective etching of

  20. Changes in genetic selection differentials and generation intervals in US Holstein dairy cattle as a result of genomic selection

    PubMed Central

    García-Ruiz, Adriana; Cole, John B.; VanRaden, Paul M.; Wiggans, George R.; Ruiz-López, Felipe J.; Van Tassell, Curtis P.

    2016-01-01

    Seven years after the introduction of genomic selection in the United States, it is now possible to evaluate the impact of this technology on the population. Selection differential(s) (SD) and generation interval(s) (GI) were characterized in a four-path selection model that included sire(s) of bulls (SB), sire(s) of cows (SC), dam(s) of bulls (DB), and dam(s) of cows (DC). Changes in SD over time were estimated for milk, fat, and protein yield; somatic cell score (SCS); productive life (PL); and daughter pregnancy rate (DPR) for the Holstein breed. In the period following implementation of genomic selection, dramatic reductions were seen in GI, especially the SB and SC paths. The SB GI reduced from ∼7 y to less than 2.5 y, and the DB GI fell from about 4 y to nearly 2.5 y. SD were relatively stable for yield traits, although modest gains were noted in recent years. The most dramatic response to genomic selection was observed for the lowly heritable traits DPR, PL, and SCS. Genetic trends changed from close to zero to large and favorable, resulting in rapid genetic improvement in fertility, lifespan, and health in a breed where these traits eroded over time. These results clearly demonstrate the positive impact of genomic selection in US dairy cattle, even though this technology has only been in use for a short time. Based on the four-path selection model, rates of genetic gain per year increased from ∼50–100% for yield traits and from threefold to fourfold for lowly heritable traits. PMID:27354521

  1. A survey of laser and selected optical systems for remote measurement of pollutant gas concentrations

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Menzies, R. T.

    1983-01-01

    Applications of the Differential Absorption Lidar (DIAL) technique to the remote sensing of pollutant gases are surveyed. In the DIAl technique, the differential absorption of two laser beams reflected back to a receiver from a target determines the concentration of the gas being studied. The types of instruments available are considered in detail: dye lidar (to measure nitrogen dioxide, sulfur dioxide, and ozone); carbon dioxide laser (for ozone, ethylene, ammonia, and hydrazine), helium-neon laser (for methane); hydrogen fluoride laser (for HF); and tunable diode laser (for nitric oxide and carbon monoxide). DIAL instruments are compared with other optical remote sensors such as Fourier-transform infrared spectrometers, correlation spectrometers (COSPEC and GASPEC), and grating spectrometers; and criteria for the selection of an appropriate gas measuring system are suggested. Laser and other optical remote sensors are found to be cost effective in many cases, despite the fact that they are more costly than point-monitoring systems.

  2. Concentrations of Selected Pharmaceuticals and Antibiotics in South-Central Pennsylvania Waters, March through September 2006

    USGS Publications Warehouse

    Loper, Connie A.; Crawford, J. Kent; Otto, Kim L.; Manning, Rhonda L.; Meyer, Michael T.; Furlong, Edward T.

    2007-01-01

    This report presents environmental and quality-control data from analyses of 15 pharmaceutical and 31 antibiotic compounds in water samples from streams and wells in south-central Pennsylvania. The analyses are part of a study by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Environmental Protection (PADEP) to define concentrations of selected emerging contaminants in streams and well water in Pennsylvania. Sampling was conducted at 11 stream sites and at 6 wells in 9 counties of south-central Pennsylvania. Five of the streams received municipal wastewater and 6 of the streams received runoff from agricultural areas dominated by animal-feeding operations. For all 11 streams, samples were collected at locations upstream and downstream of the municipal effluents or animal-feeding operations. All six wells were in agricultural settings. A total of 120 environmental samples and 21 quality-control samples were analyzed for the study. Samples were collected at each site in March/April, May, July, and September 2006 to obtain information on changes in concentration that could be related to seasonal use of compounds. For streams, 13 pharmaceuticals and 11 antibiotics were detected at least 1 time. Detections included analytical results that were estimated or above the minimum reporting limits. Seventy-eight percent of all detections were analyzed in samples collected downstream from municipal-wastewater effluents. For streams receiving wastewater effluents, the pharmaceuticals caffeine and para-xanthine (a degradation product of caffeine) had the greatest concentrations, 4.75 ug/L (micrograms per liter) and 0.853 ug/L, respectively. Other pharmaceuticals and their respective maximum concentrations were carbamazepine (0.516 ug/L) and ibuprofen (0.277 ug/L). For streams receiving wastewater effluents, the antibiotic azithromycin had the greatest concentration (1.65 ug/L), followed by sulfamethoxazole (1.34 ug/L), ofloxacin (0.329 ug

  3. [The influence of periodontal diseases on the concentration of selected metals in saliva].

    PubMed

    Herman, Małgorzata; Golasik, Magdalena; Kurhańska-Flisykowska, Anna; Kulza, Maksymilian; Chesy, Paulina; Wyganowska-Swiatkowska, Marzena; Woźniak, Anna; Seńczuk-Przybyłowksa, Monika; Stopa, Janina; Parczewski, Andrzej; Florek, Ewa; Piekoszewski, Wojciech

    2012-01-01

    Analysis of elements (mainly metals) in biological materials provides a challenge for analytics. It results from complex matrix of this kind of samples and strict requirements for purity at all stages of the analytical process. Over the years many effective methods for determination of metals in body fluids have been developed, which link with searching for the association between elemental composition of human body and various diseases. The aim of the investigation was to study the usefulness of available methodology to determination of selected metals in saliva and blood of patients with periodontitis and healthy controls by two techniques" ICP-MS and ICP-OES. Next statistical analysis of the data statistical was carried out. The influence of periodontal disease upon the concentrations of selected metals (Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Pb and Zn) in saliva was examined, as well the attempt to classify samples of patients with periodontitis and healthy individuals correctly was made. Additionally mutual relations between analytes in examined materials were determined by computing the Pearson's correlation coefficient and principal component analysis (PCA).

  4. Selective removal of photocatalytic non-degradable fluorosurfactants from reverse osmosis concentrate.

    PubMed

    Lin, Xuan Hao; Sriramulu, Deepa; Li, Sam Fong Yau

    2015-01-01

    Recently photocatalytic treatment of municipal reverse osmosis concentrate (ROC) has drawn increasing attention due to its relatively high efficiency and low cost. However, photocatalytic reactions by commercially available TiO₂ are not able to degrade fluorosurfactants in the ROC sample due to the absence of photoreactive groups in these compounds. Here we investigated adsorption and coagulation methods and their efficiencies in removing fluorosurfactants. The analysis and characterization methods included mass spectrometry (LC-QToF), total organic carbon (TOC), fluorescence & UV–Visible spectra, SEM, IR, N2 sorption, zeta potential, and elemental analysis. Ferric chloride (FER) coagulation was found to be quite efficient in removing fluorosurfactants, while powdered activated carbon (PAC) adsorption was inefficient. The FER pre-treatment process was found to perform better than the post-treatment process in removing the fluorosurfactants. FER selectively removed the bulky fluorosurfactants with long branches but not the slim ones with short or no branches. At a concentration of 10.60 mM, FER could efficiently remove 62.19% fluorosurfactants in total from the ROC sample. The applicability of Freundlich and Langmuir models for the adsorption processes was also investigated. FER was able to remove fluorosurfactant while PAC unable. While the PAC removal mechanism was adsorption, the FER coagulation mechanism was far more complicated.

  5. Correlation of concentrations of selected trace elements with Gleason grade of prostate tissues

    PubMed Central

    Kwiatek, W. M.; Banas, K.; Gajda, M.; Pawlicki, B.; Cichocki, T.

    2010-01-01

    The causes of prostate cancer are still obscure but some evidence indicates that there is a close connection between several trace elements and processes which may lead to malignant cells. In our study the microbeam synchrotron radiation X-ray fluorescence emission (micro-SRIXE) technique was applied for quantitative analysis of selected elements. For the first time, we correlate the concentrations of Mn, Fe, Cu, and Zn with the clinical stage of the prostate cancer at the time of operation (described by Gleason grade). Serial sections of prostate tissues were collected from patients undergoing radical prostatectomy. One section, stained with hematoxylin and eosin, was prepared for histopathological analysis; a second, adjacent unstained section was used in micro-SRIXE experiments. All experiments were performed at beamline L at HASYLAB, DESY, Germany. Our results seem to be valuable in light of the determination of the changes in the concentrations of trace elements as a potential diagnostic marker and their etiological involvement in the different stages of prostate diseases. PMID:20499115

  6. Selective removal of photocatalytic non-degradable fluorosurfactants from reverse osmosis concentrate.

    PubMed

    Lin, Xuan Hao; Sriramulu, Deepa; Li, Sam Fong Yau

    2015-01-01

    Recently photocatalytic treatment of municipal reverse osmosis concentrate (ROC) has drawn increasing attention due to its relatively high efficiency and low cost. However, photocatalytic reactions by commercially available TiO₂ are not able to degrade fluorosurfactants in the ROC sample due to the absence of photoreactive groups in these compounds. Here we investigated adsorption and coagulation methods and their efficiencies in removing fluorosurfactants. The analysis and characterization methods included mass spectrometry (LC-QToF), total organic carbon (TOC), fluorescence & UV–Visible spectra, SEM, IR, N2 sorption, zeta potential, and elemental analysis. Ferric chloride (FER) coagulation was found to be quite efficient in removing fluorosurfactants, while powdered activated carbon (PAC) adsorption was inefficient. The FER pre-treatment process was found to perform better than the post-treatment process in removing the fluorosurfactants. FER selectively removed the bulky fluorosurfactants with long branches but not the slim ones with short or no branches. At a concentration of 10.60 mM, FER could efficiently remove 62.19% fluorosurfactants in total from the ROC sample. The applicability of Freundlich and Langmuir models for the adsorption processes was also investigated. FER was able to remove fluorosurfactant while PAC unable. While the PAC removal mechanism was adsorption, the FER coagulation mechanism was far more complicated. PMID:25465720

  7. IMPACT OF AN OZONE GENERATOR AIR CLEANER ON STYRENE CONCENTRATIONS IN AN INDOOR AIR QUALITY RESEARCH CHAMBER

    EPA Science Inventory

    The paper gives results of an investigation of the impact of an ozone generator air cleaner on vapor-phase styrene concentrations in a full-scale indoor air quality test chamber. The time history of the concentrations of styrene and ozone is well predicted by a simulation model u...

  8. Selective concentration of cesium in analcime during hydrothermal alteration, Yellowstone National Park, Wyoming

    USGS Publications Warehouse

    Keith, T.E.C.; Thompson, J.M.; Mays, R.E.

    1983-01-01

    Chemical and mineralogical studies of fresh and hydrothermally altered rhyolitic material in Upper and Lower Geyser Basins, Yellowstone National Park, show that all the altered rocks are enriched in Cs and that Cs is selectively concentrated in analcime. The Cs content of unaltered rhyolite lava flows, including those from which the altered sediments are derived, ranges from 2.5 to 7.6 ppm. The Cs content of analcime-bearing altered sedimentary rocks is as high as 3000 ppm, and in clinoptilolite-bearing altered sedimentary rocks Cs content is as high as 180 ppm. Altered rhyolite lava flows which were initially vitrophyres, now contain up to 250 ppm Cs, and those which were crystallized prior to hydrothermal alteration contain up to 14 ppm. Mineral concentrates of analcime contain as much as 4700 ppm Cs. The Cs must have been incorporated into the analcime structure during crystallization, rather than by later cation substitution, because analcime does not readily exchange Cs. The Cs Cl of the fluids circulating through the hydrothermal system varies, suggesting that Cs is not always a conservative ion and that Cs is lost from upflowing thermal waters due to water-rock interaction resulting in crystallization of Cs-bearing analcime. The source of Cs for Cs enrichment of the altered rocks is from leaching of rhyolitic rocks underlying the geyser basins, and from the top of the silicic magma chamber that underlies the area. Analcime is an important natural Cs sink, and the high Cs concentrations reported here may prove to be an important indicator of the environment of analcime crystallization. ?? 1983.

  9. Analysis of 28 generations of selection for reproduction, growth, and carcass traits in swine.

    PubMed

    Hsu, W L; Johnson, R K

    2014-11-01

    Selection (28 generations, G) in a Large White-Landrace composite population for traits aimed at increasing live pigs born per litter (BA), with additional selection for increased 180-d weight (WT180) and longissimus muscle area (LMA) and decreased back fat (BF10) in the last 8 generations, was practiced. Objectives herein were to estimate genetic and phenotypic responses and genetic parameters (n = 1,883 to 54,174) and to investigate whether a plateau in response for BA occurred. Line 2 (L2) was selected for an index of ovulation rate and embryo survival (G0 to G11), fully formed pigs (FF) per litter (G12 to 14), and BA and pig birth weight (PBW, G15 to G19), and its control line (LC1) was selected randomly (G0 to G21). Line 4 (L4), derived from L2, and line 5 (L5), derived from LC1, at G8 were selected in 2 stages for ovulation rate and FF (G9 to G16) and BA and PBW (G17 to G19), and their control (LC6) was selected randomly. At G20, L4 and L5 were crossed to form L45, and L4 and L2 were crossed to continue L2; L2 and L45 were subsequently selected for BA, WT180, LMA, and BF10 (G21 to G28). At G21, LC1 and LC6 were reciprocally crossed to form LC16, control for L2, and LC61, control for L45. Selection in L2 and L45 was first for BA and then for other traits among pigs selected for BA. Line sizes were 40 to 60 litters by 15 to 20 sires/G. Cumulative selection differentials (CSD) were calculated. MTDFREML was used to estimate variance components, EBV, and responses. Genetic changes at G28 in L2 were 4.63 FF and 3.66 BA, with 72% (FF) and 86% (BA) of the change occurring after G11. Two-stage selection produced similar responses (P < 0.01) in FF in L4 and L5 (0.27 and 0.29 pigs/G) but a greater response in BA in L5 (0.19 vs. 0.28 pigs/G). Genetic change in L45 from G20 to G28 was 0.17 pigs/G for both FF and BA (P < 0.01). Genetic changes at G28 in L45 were 4.16 FF and 3.68 BA. Genetic correlations of reproductive and growth traits were near zero, ranging from -0

  10. Multi-wavelength synchronous pulse burst generation with a wavelength selective switch.

    PubMed

    Roelens, Michaël A; Bolger, Jeremy A; Williams, David; Eggleton, Benjamin J

    2008-07-01

    We demonstrate simultaneous pulse-shaping at different ports of a rapidly tunable wavelength selective switch at a base rate of 40 GHz, based on Fourier-domain pulse shaping. Various pulse bursts are generated and accurately characterized with a linear spectrographic method.

  11. Response to multi-generational selection under elevated [CO2] in two temperature regimes suggests enhanced carbon assimilation and increased reproductive output in Brassica napus L.

    PubMed Central

    Frenck, Georg; van der Linden, Leon; Mikkelsen, Teis Nørgaard; Brix, Hans; Jørgensen, Rikke Bagger

    2013-01-01

    Functional plant traits are likely to adapt under the sustained pressure imposed by environmental changes through natural selection. Employing Brassica napus as a model, a multi-generational study was performed to investigate the potential trajectories of selection at elevated [CO2] in two different temperature regimes. To reveal phenotypic divergence at the manipulated [CO2] and temperature conditions, a full-factorial natural selection regime was established in a phytotron environment over the range of four generations. It is demonstrated that a directional response to selection at elevated [CO2] led to higher quantities of reproductive output over the range of investigated generations independent of the applied temperature regime. The increase in seed yield caused an increase in aboveground biomass. This suggests quantitative changes in the functions of carbon sequestration of plants subjected to increased levels of CO2 over the generational range investigated. The results of this study suggest that phenotypic divergence of plants selected under elevated atmospheric CO2 concentration may drive the future functions of plant productivity to be different from projections that do not incorporate selection responses of plants. This study accentuates the importance of phenotypic responses across multiple generations in relation to our understanding of biogeochemical dynamics of future ecosystems. Furthermore, the positive selection response of reproductive output under increased [CO2] may ameliorate depressions in plant reproductive fitness caused by higher temperatures in situations where both factors co-occur. PMID:23762504

  12. Evaluation of Oxygen Concentrators and Chemical Oxygen Generators at Altitude and Temperature Extremes.

    PubMed

    Blakeman, Thomas C; Rodriquez, Dario; Britton, Tyler J; Johannigman, Jay A; Petro, Michael C; Branson, Richard D

    2016-05-01

    Oxygen cylinders are heavy and present a number of hazards, and liquid oxygen is too heavy and cumbersome to be used in far forward environments. Portable oxygen concentrators (POCs) and chemical oxygen generators (COGs) have been proposed as a solution. We evaluated 3 commercially available POCs and 3 COGs in a laboratory setting. Altitude testing was done at sea level and 8,000, 16,000, and 22,000 ft. Temperature extreme testing was performed after storing devices at 60°C and -35°C for 24 hours. Mean FIO2 decreased after storage at -35°C with Eclipse and iGo POCs and also at the higher volumes after storage at 60°C with the Eclipse. The iGo ceased to operate at 16,000 ft, but the Eclipse and Saros were unaffected by altitude. Oxygen flow, duration of operation, and total oxygen volume varied between COGs and within the same device type. Output decreased after storage at -35°C, but increased at each altitude as compared to sea level. This study showed significant differences in the performance of POCs and COGs after storage at temperature extremes and with the COGs at altitude. Clinicians must understand the performance characteristics of devices in all potential environments. PMID:27168568

  13. Development of low-concentration mercury adsorbents from biohydrogen-generation agricultural residues using sulfur impregnation.

    PubMed

    Hsi, Hsing-Chengi; Tsai, Cheng-Yen; Kuo, Tien-Ho; Chiang, Cheng-Sheng

    2011-08-01

    Mercury adsorbents were derived from waste biohydrogen-generation barley husk and rice husk via carbonization, steam activation, and sulfur impregnation at 300-650°C. The samples derived from agricultural residues showed a greater Hg(0) adsorption than that of a coal-based activated carbon, confirming the feasibility of resource recovery of these agricultural residuals for low-concentration gaseous Hg adsorption. Sulfur impregnation reduced both the surface area and pore volume of the samples, with lower temperature causing a greater decrease. Elevating the impregnation temperature increased the organic sulfur contents, suggesting that in addition to elemental sulfur, organic sulfur may also act as active sites to improve Hg(0) adsorption. Oxygen and sulfur functional groups accompanying the microporous structures may account for the enhancing Hg(0) adsorption of the raw and sulfur-treated samples, respectively. The pseudo-second-order model can best describe the chemisorption characteristics, implying that Hg(0) adsorption on the samples was in a bimolecular reaction form.

  14. Geometric Effects on Power Generation by Reverse Electrodialysiswith Self-induced Electrolyte Flow in Ion-Selective Nanochannels

    NASA Astrophysics Data System (ADS)

    Kim, Byoung Jae; Kim, Dong-Kwon; Lee, Seung-Hyun

    2012-11-01

    Recently, solid-state nanofluidic channels or nanopores have been demonstrated experimentally to serve as ion-selective membranes for small reverse electrodialysis systems. Ions of opposite charge to that of the surface (counter-ions) are attracted toward the surface while ions of like charge (co-ions) are repelled from the surface. As a result, the counter-ions are preferentially transported over the co-ions in the charged nanochannels. Under a concentration gradient, the ions diffuse spontaneously across the nanochannels, and a portion of the Gibbs free energy of mixing can be harvested continuously from the nanochannels by means of the net diffusion current. In the present study, power generation by reverse eletrodialysis in ion-selective nanochannels is numerically investigated by solving the Nernst-Planck equation for the ionic concentrations, the Poisson equation for the electric potential, and the Navier-Stokes equation for the electrolyte velocity simultaneously. We elucidated the effect of various parameters on power generation such as geometry of channel cross section, channel length, hydraulic diameter and the surface charge density etc. Corresponding Author.

  15. Sauder Woodworking Company, a waste wood electric generating facility with Selective Catalytic Reduction

    SciTech Connect

    Johnson, N.H.

    1995-08-01

    Although NO{sub x} is the focus of this conference and Selective Catalytic Reduction (SCR) is the topic of this paper, it is important to understand the development of the project purpose and the reasons for the requirements of an SCR. Sauder Woodworking Company (SWC) generates waste wood as a byproduct of its manufacturing operation. Studies suggested that energy costs could be reduced by utilizing the waste wood to generate steam and electricity. Since the wood is dry, it is possible to utilize suspension burner technology. Two (2) 45,000 lb/hr boilers produce steam at 625 psig and 750{degrees}F. Each boiler is equipped with an economizer, mechanical dust collector, selective catalytic reduction, and an electrostatic precipitator. Electricity is produced from two (2) 3500 KW turbine generators operating in a condensing mode with steam extraction used for plant heating and process. As part of the plant design, an SCR was required for each boiler for environmental reasons.

  16. Concentration of ions in selected bottled water samples sold in Malaysia

    NASA Astrophysics Data System (ADS)

    Aris, Ahmad Zaharin; Kam, Ryan Chuan Yang; Lim, Ai Phing; Praveena, Sarva Mangala

    2013-03-01

    Many consumers around the world, including Malaysians, have turned to bottled water as their main source of drinking water. The aim of this study is to determine the physical and chemical properties of bottled water samples sold in Selangor, Malaysia. A total of 20 bottled water brands consisting of `natural mineral (NM)' and `packaged drinking (PD)' types were randomly collected and analyzed for their physical-chemical characteristics: hydrogen ion concentration (pH), electrical conductivity (EC) and total dissolved solids (TDS), selected major ions: calcium (Ca), potassium (K), magnesium (Mg) and sodium (Na), and minor trace constituents: copper (Cu) and zinc (Zn) to ascertain their suitability for human consumption. The results obtained were compared with guideline values recommended by World Health Organization (WHO) and Malaysian Ministry of Health (MMOH), respectively. It was found that all bottled water samples were in accordance with the guidelines set by WHO and MMOH except for one sample (D3) which was below the pH limit of 6.5. Both NM and PD bottled water were dominated by Na + K > Ca > Mg. Low values for EC and TDS in the bottled water samples showed that water was deficient in essential elements, likely an indication that these were removed by water treatment. Minerals like major ions were present in very low concentrations which could pose a risk to individuals who consume this water on a regular basis. Generally, the overall quality of the supplied bottled water was in accordance to standards and guidelines set by WHO and MMOH and safe for consumption.

  17. Automated Gel Size Selection to Improve the Quality of Next-generation Sequencing Libraries Prepared from Environmental Water Samples.

    PubMed

    Uyaguari-Diaz, Miguel I; Slobodan, Jared R; Nesbitt, Matthew J; Croxen, Matthew A; Isaac-Renton, Judith; Prystajecky, Natalie A; Tang, Patrick

    2015-04-17

    Next-generation sequencing of environmental samples can be challenging because of the variable DNA quantity and quality in these samples. High quality DNA libraries are needed for optimal results from next-generation sequencing. Environmental samples such as water may have low quality and quantities of DNA as well as contaminants that co-precipitate with DNA. The mechanical and enzymatic processes involved in extraction and library preparation may further damage the DNA. Gel size selection enables purification and recovery of DNA fragments of a defined size for sequencing applications. Nevertheless, this task is one of the most time-consuming steps in the DNA library preparation workflow. The protocol described here enables complete automation of agarose gel loading, electrophoretic analysis, and recovery of targeted DNA fragments. In this study, we describe a high-throughput approach to prepare high quality DNA libraries from freshwater samples that can be applied also to other environmental samples. We used an indirect approach to concentrate bacterial cells from environmental freshwater samples; DNA was extracted using a commercially available DNA extraction kit, and DNA libraries were prepared using a commercial transposon-based protocol. DNA fragments of 500 to 800 bp were gel size selected using Ranger Technology, an automated electrophoresis workstation. Sequencing of the size-selected DNA libraries demonstrated significant improvements to read length and quality of the sequencing reads.

  18. Concentrated solar power generation: Firm and dispatchable capacity for Brazil's solar future?

    NASA Astrophysics Data System (ADS)

    Tomaschek, Jan; Haasz, Thomas; Fahl, Ulrich

    2016-05-01

    The Brazilian electricity mix is currently dominated by renewable energy forms, foremost hydropower. Large additional capacity demands are expected in the mid-term future but additional potential for hydro power is limited. In addition it is planned to construct more than 17 GW of wind power and additional capacity of photovoltaics (PV). Due to the fluctuating nature of such renewables, however, wind and PV are hardly able to provide firm capacity. Concentrated solar power (CSP) might be a feasible option to provide firm and dispatchable capacity at low carbon emissions. This study analyses the opportunities for integrating CSP into the Brazilian energy system. Making use of the TiPS-B model, a novel application of the optimization model generator TIMES, we compare different climate protection strategies with a reference scenario and analyze the contribution of CSP to the electricity mix. The analysis covers various types of CSP power plants with molten salt energy storage where we look at possible dispatch strategies considering the fluctuations in electricity supply and use. The consideration of solar water heaters (SWH) is the first step to transfer the power system model to an energy system model that is capable of showing the benefits of energy saving measures on the demand side. It can be demonstrated that the Brazilian power system is likely to change significantly in future. This development would go hand in hand with a strong increase in carbon emissions if no mitigation actions are taken and fossil fueled power plants are used to fill the gap in capacity. CSP power plants are found as a feasible alternative for covering the demand while taking carbon mitigation actions. In a scenario, aiming at 4 and 2 degrees global warming, CSP provides for 7.6 GW and 14.6 GW capacity in 2050, respectively. Different storage configurations are used to provide energy in the evening hours to cover the demand peak providing a strong benefit over photovoltaic electricity

  19. Low-Cost High-Concentration Photovoltaic Systems for Utility Power Generation

    SciTech Connect

    McConnell, R.; Garboushian, V.; Gordon, R.; Dutra, D.; Kinsey, G.; Geer, S.; Gomez, H.; Cameron, C.

    2012-03-31

    Under DOE's Technology Pathway Partnership (TPP) program, Amonix, Inc. developed a new generation of high-concentration photovoltaic systems using multijunction technology and established the manufacturing capacity needed to supply multi-megawatt power plants buing using the new Amonix 7700-series solar energy systems. For this effort, Amonix Collaborated with a variety of suppliers and partners to complete project tasks. Subcontractors included: Evonik/Cyro; Hitek; the National Renewable Energy Laboratory (NREL); Raytech; Spectrolab; UL; University of Nevada, Las Vegas; and TUV Rheinland PTL. The Amonix TPP tasks included: Task 1: Multijunction Cell Optimization for Field Operation, Task 2: Fresnel Lens R&D, Task 3: Cell Package Design & Production, Task 4: Standards Compliance and Reliability Testing, Task 5: Receiver Plate Production, Task 6: MegaModule Performance, Task 7: MegaModule Cost Reduction, Task 8: Factory Setup and MegaModule Production, Task 9: Tracker and Tracking Controller, Task 10: Installation and Balance of System (BOS), Task 11: Field Testing, and Task 12: Solar Advisor Modeling and Market Analysis. Amonix's TPP addressed nearly the complete PV value chain from epitaxial layer design and wafer processing through system design, manufacturing, deployment and O&M. Amonix has made progress toward achieving these reduced costs through the development of its 28%+ efficient MegaModule, reduced manufacturing and installation cost through design for manufacturing and assembly, automated manufacturing processes, and reduced O&M costs. Program highlights include: (1) Optimized multijunction cell and cell package design to improve performance by > 10%; (2) Updated lens design provided 7% increased performance and higher concentration; (3) 28.7% DC STC MegaModule efficiency achieved in Phase II exceeded Phase III performance goal; (4) New 16' focal length MegaModule achieved target materials and manufacturing cost reduction; (5) Designed and placed into

  20. CB2 cannabinoid receptor is a novel target for third-generation selective estrogen receptor modulators bazedoxifene and lasofoxifene.

    PubMed

    Kumar, Pritesh; Song, Zhao-Hui

    2014-01-01

    The purpose of the current study was to investigate the ability of the third-generation selective estrogen receptor modulators (SERMs) bazedoxifene and lasofoxifene to bind and act on CB2 cannabinoid receptor. We have identified, for the first time, that CB2 is a novel target for bazedoxifene and lasofoxifene. Our results showed that bazedoxifene and lasofoxifene were able to compete for specific [(3)H]CP-55,940 binding to CB2 in a concentration-dependent manner. Our data also demonstrated that by acting on CB2, bazedoxifene and lasofoxifene concentration-dependently enhanced forskolin-stimulated cAMP accumulation. Furthermore, bazedoxifene and lasofoxifene caused parallel, rightward shifts of the CP-55,940, HU-210, and WIN55,212-2 concentration-response curves without altering the efficacy of these cannabinoid agonists on CB2, which indicates that bazedoxifene- and lasofoxifene-induced CB2 antagonism is most likely competitive in nature. Our discovery that CB2 is a novel target for bazedoxifene and lasofoxifene suggests that these third-generation SERMs can potentially be repurposed for novel therapeutic indications for which CB2 is a target. In addition, identifying bazedoxifene and lasofoxifene as CB2 inverse agonists also provides important novel mechanisms of actions to explain the known therapeutic effects of these SERMs. PMID:24275139

  1. Ozone concentrations at a selected high-elevation forest site downwind Mexico City

    NASA Astrophysics Data System (ADS)

    Torres-JArdon, R.

    2013-05-01

    July to September. Episodes of high concentrations occurred mainly during the dry warm months. Most of the year, nocturnal ozone levels were higher than those registered in the urban area due to the PMH altitude. As a great part of the mountain terrain regularly is above the nocturnal mixing layer formed each day on the valley floor, the ozone remanent levels above this layer in the mountains are kept isolated from urban NOx emissions generated at night. An evaluation of the AOT40 indicator shows that the forest zone is under a strong risk due to ozone pollution. A preliminary analysis of several ozone events in the PNMH shows the suppression of the diel peak, suggesting that a stratospheric intrusion of ozone occurs frequently in high-elevation sites surrounding MCMA.

  2. The influence of selected factors and sport results of endurance horses on their saliva cortisol concentration.

    PubMed

    Janczarek, I; Bereznowski, A; Strzelec, K

    2013-01-01

    The aim of the study was to define the influence of the selected factors (gender, age, transportation time, riding distance and air temperature during the ride) on the cortisol secretion and finding a correlation between the hormone level and the horses' sport results (veterinary parameters and the ride route parameters). The research was performed on 38 Arabian pure breed horses taking part in the endurance rides. The cortisol level was measured with enzyme-immunological method in saliva samples, taken four times from each horse. In order to verify the differences between the mean results the repeated measures design was applied. The significance of the differences between the mean values was determined by the Tukey test. To evaluate the interrelations between the analysed attributes Pearson's correlation analysis was applied. The cortisol level at rest was not affected by any of the analysed factors. In case of other results, the most significant influence (P < or = 0.05) was related to the gender, as well as the ride distance and air temperature during the ride. Higher cortisol level was noted in mares, horses running the longest distances and at the highest temperatures. A significant increase in the cortisol level was noted when the ride distance was longer. There were no clear correlation between the adrenal cortex activity and the veterinary parameters at different riding speed. High cortisol concentration can negatively affect the heart rate (HR) by increasing it, but it can simultaneously stimulate the body to fight dehydration.

  3. The influence of selected factors and sport results of endurance horses on their saliva cortisol concentration.

    PubMed

    Janczarek, I; Bereznowski, A; Strzelec, K

    2013-01-01

    The aim of the study was to define the influence of the selected factors (gender, age, transportation time, riding distance and air temperature during the ride) on the cortisol secretion and finding a correlation between the hormone level and the horses' sport results (veterinary parameters and the ride route parameters). The research was performed on 38 Arabian pure breed horses taking part in the endurance rides. The cortisol level was measured with enzyme-immunological method in saliva samples, taken four times from each horse. In order to verify the differences between the mean results the repeated measures design was applied. The significance of the differences between the mean values was determined by the Tukey test. To evaluate the interrelations between the analysed attributes Pearson's correlation analysis was applied. The cortisol level at rest was not affected by any of the analysed factors. In case of other results, the most significant influence (P < or = 0.05) was related to the gender, as well as the ride distance and air temperature during the ride. Higher cortisol level was noted in mares, horses running the longest distances and at the highest temperatures. A significant increase in the cortisol level was noted when the ride distance was longer. There were no clear correlation between the adrenal cortex activity and the veterinary parameters at different riding speed. High cortisol concentration can negatively affect the heart rate (HR) by increasing it, but it can simultaneously stimulate the body to fight dehydration. PMID:24195289

  4. Dissolved Concentrations, Sources, and Risk Evaluation of Selected Metals in Surface Water from Mangla Lake, Pakistan

    PubMed Central

    Saleem, Muhammad; Iqbal, Javed; Shah, Munir H.

    2014-01-01

    The present study is carried out for the assessment of water quality parameters and selected metals levels in surface water from Mangla Lake, Pakistan. The metal levels (Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, and Zn) were determined by flame atomic absorption spectrophotometry. Average levels of Cd, Co, Cr, Ni, and Pb were higher than the allowable concentrations set by national and international agencies. Principal component analysis indicated significant anthropogenic contributions of Cd, Co, Cr, Ni, and Pb in the water reservoir. Noncarcinogenic risk assessment was then evaluated using Hazard Quotient (HQing/derm) and Hazard Index (HIing/derm) following USEPA methodology. For adults and children, Cd, Co, Cr, and Pb (HQing > 1) emerged as the most important pollutants leading to noncarcinogenic concerns via ingestion route, whereas there was no risk via dermal contact of surface water. This study helps in establishing pollutant loading reduction goal and the total maximum daily loads, and consequently contributes to preserve public health and develop water conservation strategy. PMID:24744690

  5. Selection-Independent Generation of Gene Knockout Mouse Embryonic Stem Cells Using Zinc-Finger Nucleases

    PubMed Central

    Osiak, Anna; Radecke, Frank; Guhl, Eva; Radecke, Sarah; Dannemann, Nadine; Lütge, Fabienne; Glage, Silke; Rudolph, Cornelia; Cantz, Tobias; Schwarz, Klaus; Heilbronn, Regine; Cathomen, Toni

    2011-01-01

    Gene knockout in murine embryonic stem cells (ESCs) has been an invaluable tool to study gene function in vitro or to generate animal models with altered phenotypes. Gene targeting using standard techniques, however, is rather inefficient and typically does not exceed frequencies of 10−6. In consequence, the usage of complex positive/negative selection strategies to isolate targeted clones has been necessary. Here, we present a rapid single-step approach to generate a gene knockout in mouse ESCs using engineered zinc-finger nucleases (ZFNs). Upon transient expression of ZFNs, the target gene is cleaved by the designer nucleases and then repaired by non-homologous end-joining, an error-prone DNA repair process that introduces insertions/deletions at the break site and therefore leads to functional null mutations. To explore and quantify the potential of ZFNs to generate a gene knockout in pluripotent stem cells, we generated a mouse ESC line containing an X-chromosomally integrated EGFP marker gene. Applying optimized conditions, the EGFP locus was disrupted in up to 8% of ESCs after transfection of the ZFN expression vectors, thus obviating the need of selection markers to identify targeted cells, which may impede or complicate downstream applications. Both activity and ZFN-associated cytotoxicity was dependent on vector dose and the architecture of the nuclease domain. Importantly, teratoma formation assays of selected ESC clones confirmed that ZFN-treated ESCs maintained pluripotency. In conclusion, the described ZFN-based approach represents a fast strategy for generating gene knockouts in ESCs in a selection-independent fashion that should be easily transferrable to other pluripotent stem cells. PMID:22194948

  6. Selective Media for Actinide Collection and Pre-Concentration: Results of FY 2006 Studies

    SciTech Connect

    Lumetta, Gregg J.; Addleman, Raymond S.; Hay, Benjamin P.; Hubler, Timothy L.; Levitskaia, Tatiana G.; Sinkov, Sergey I.; Snow, Lanee A.; Warner, Marvin G.; Latesky, Stanley L.

    2006-11-17

    In this work, we have investigated new materials for potential use in automated radiochemical separations. The work can be divided into three primary tasks: (1) synthesis of new ligands with high affinity for actinide ions, (2) evaluation of new materials for actinide ion affinity, and (3) computational design of advanced ligand architectures for highly selective binding of actinide ions. Ligand Synthesis Work was conducted on synthesizing Kl?ui ligand derivatives containing functionalized pendant groups on the cyclopentadienyl ring. The functionalized pendent groups would allow these ligands to be attached to organic and inorganic solid supports. This work focused on synthesizing the compound Na[Cp?Co(PO(OC2H5)2)3], where Cp?= C5H4C(O)OCH3. Synthesizing this compound is feasible, but the method used in FY 2006 produced an impure material. A modified synthetic scheme has been developed and will be pursued in FY 2007. Work was also initiated on synthesizing bicyclic diamides functionalized for binding to polymeric resins or other surfaces. Researchers at the University of Oregon are collaborators in this work. To date, this effort has focused on synthesizing and characterizing a symmetrically substituted bicyclic diamide ligand with the ?COOH functionality. Again, this synthetic effort will continue into FY 2007. Separations Material Evaluation Work was conducted in FY 2006 to provide a more extensive set of data on the selectivity and affinity of extraction chromatography resins prepared by sorption of Kl?ui ligand onto an inert macroreticular polymeric support. Consistent with previous observations, it was found that these materials strongly bind tetravalent actinides. These materials also adsorb trivalent actinides at low nitric acid concentrations, but the affinity for the trivalent actinides decreases with increasing nitric acid concentration. These materials have relatively low affinity for U(VI), but they do sorb U(VI) to a greater extent than Am(III) at [HNO

  7. Wavelength-selective orbital angular momentum generation based on a plasmonic metasurface.

    PubMed

    Yang, Kunpeng; Pu, Mingbo; Li, Xiong; Ma, Xiaoliang; Luo, Jun; Gao, Hui; Luo, Xiangang

    2016-06-16

    Nanoapertures with space-variant geometries are designed in a gold thin film to construct an ultrathin plasmonic metasurface, which has been demonstrated both numerically and experimentally to selectively generate and focus orbital angular momentum (OAM) beams with different topological charges at the wavelengths of 930 nm and 766 nm, respectively. Moreover, the interference patterns between the different circularly polarized transmission light were used to confirm the topological charges unambiguously. The agreement between the simulated and measured results suggests that the metasurface of wavelength-selective OAM modes may have potential applications in future optical communication systems. PMID:27271957

  8. Wavelength-selective orbital angular momentum generation based on a plasmonic metasurface

    NASA Astrophysics Data System (ADS)

    Yang, Kunpeng; Pu, Mingbo; Li, Xiong; Ma, Xiaoliang; Luo, Jun; Gao, Hui; Luo, Xiangang

    2016-06-01

    Nanoapertures with space-variant geometries are designed in a gold thin film to construct an ultrathin plasmonic metasurface, which has been demonstrated both numerically and experimentally to selectively generate and focus orbital angular momentum (OAM) beams with different topological charges at the wavelengths of 930 nm and 766 nm, respectively. Moreover, the interference patterns between the different circularly polarized transmission light were used to confirm the topological charges unambiguously. The agreement between the simulated and measured results suggests that the metasurface of wavelength-selective OAM modes may have potential applications in future optical communication systems.

  9. Selectively enhanced photocurrent generation in twisted bilayer graphene with van Hove singularity.

    PubMed

    Yin, Jianbo; Wang, Huan; Peng, Han; Tan, Zhenjun; Liao, Lei; Lin, Li; Sun, Xiao; Koh, Ai Leen; Chen, Yulin; Peng, Hailin; Liu, Zhongfan

    2016-01-01

    Graphene with ultra-high carrier mobility and ultra-short photoresponse time has shown remarkable potential in ultrafast photodetection. However, the broad and weak optical absorption (∼ 2.3%) of monolayer graphene hinders its practical application in photodetectors with high responsivity and selectivity. Here we demonstrate that twisted bilayer graphene, a stack of two graphene monolayers with an interlayer twist angle, exhibits a strong light-matter interaction and selectively enhanced photocurrent generation. Such enhancement is attributed to the emergence of unique twist-angle-dependent van Hove singularities, which are directly revealed by spatially resolved angle-resolved photoemission spectroscopy. When the energy interval between the van Hove singularities of the conduction and valance bands matches the energy of incident photons, the photocurrent generated can be significantly enhanced (up to ∼ 80 times with the integration of plasmonic structures in our devices). These results provide valuable insight for designing graphene photodetectors with enhanced sensitivity for variable wavelength.

  10. Generation of a Mouse Full-length Balancer with Versatile Cassette-shuttling Selection Strategy.

    PubMed

    Ye, Zhisheng; Sun, Lei; Li, Rongbo; Han, Min; Zhuang, Yuan; Wu, Xiaohui; Xu, Tian

    2016-01-01

    Balancer chromosomes are important tools for a variety of genetic manipulations in lower model organisms, owing to their ability to suppress recombination. In mouse, however, such effort has not been accomplished, mostly due to the size of the chromosomes and the complexity of multiple step chromosomal engineering. We developed an effective and versatile cassette-shuttling selection (CASS) strategy involving only two selection markers to achieve the sequential production of multiple large inversions along the chromosome. Using this strategy, we successfully generated the first full-length balancer in mice and showed that Balancer 17M-GFP can efficiently suppress recombination. Our study has not only generated a useful genetic resource, but also provided a strategy for constructing mammalian balancer chromosomes.

  11. Selectively enhanced photocurrent generation in twisted bilayer graphene with van Hove singularity

    PubMed Central

    Yin, Jianbo; Wang, Huan; Peng, Han; Tan, Zhenjun; Liao, Lei; Lin, Li; Sun, Xiao; Koh, Ai Leen; Chen, Yulin; Peng, Hailin; Liu, Zhongfan

    2016-01-01

    Graphene with ultra-high carrier mobility and ultra-short photoresponse time has shown remarkable potential in ultrafast photodetection. However, the broad and weak optical absorption (∼2.3%) of monolayer graphene hinders its practical application in photodetectors with high responsivity and selectivity. Here we demonstrate that twisted bilayer graphene, a stack of two graphene monolayers with an interlayer twist angle, exhibits a strong light–matter interaction and selectively enhanced photocurrent generation. Such enhancement is attributed to the emergence of unique twist-angle-dependent van Hove singularities, which are directly revealed by spatially resolved angle-resolved photoemission spectroscopy. When the energy interval between the van Hove singularities of the conduction and valance bands matches the energy of incident photons, the photocurrent generated can be significantly enhanced (up to ∼80 times with the integration of plasmonic structures in our devices). These results provide valuable insight for designing graphene photodetectors with enhanced sensitivity for variable wavelength. PMID:26948537

  12. Trace element concentration and speciation in selected urban soils in New York City.

    PubMed

    Burt, R; Hernandez, L; Shaw, R; Tunstead, R; Ferguson, R; Peaslee, S

    2014-01-01

    A long history of urbanization and industrialization has affected trace elements in New York City (NYC) soils. Selected NYC pedons were analyzed by aqua regia microwave digestion and sequential chemical extraction as follows: water soluble (WS); exchangeable (EX); specifically sorbed/carbonate bound (SS/CAR); oxide-bound (OX); organic/sulfide bound (OM/S). Soils showed a range in properties (e.g., pH 3.9 to 7.4). Sum of total extractable (SUMTE) trace elements was higher in NYC parks compared to Bronx River watershed sites. NYC surface horizons showed higher total extractable (TE) levels compared to US non-anthropogenic soils. TE levels increased over 10 year in some of the relatively undisturbed and mostly wooded park sites. Surface horizons of park sites with long-term anthropogenic inputs showed elevated TE levels vs. subsurface horizons. Conversely, some Bronx River watershed soils showed increased concentrations with depth, reflective of their formation in a thick mantle of construction debris increasing with depth and intermingled with anthrotransported soil materials. Short-range variability was evident in primary pedons and satellite samples (e.g., Pb 253 ± 143 mg/kg). Long-range variability was indicated by PbTE (348 versus 156 mg/kg) and HgTE (1 versus 0.3 mg/kg) concentrations varying several-fold in the same soil but in different geographic locations. Relative predominance of fractions: RES (37 %) > SS/CAR (22 %) > OX (20 %) > OM/S (10 %) > EX (7 %) > WS (4 %). WS and EX fractions were greatest for Hg (7 %) and Cd (14 %), respectively. RES was predominant fraction for Co, Cr, Ni, and Zn (41 to 51 %); SS/CAR for Cd and Pb (40 and 63 %); OM/S for Cu and Hg (36 and 37 %); and OX for As (59 %).

  13. Development of Decision Model for Selection of Appropriate Power Generation System Using Distance Based Approach Method

    NASA Astrophysics Data System (ADS)

    Widiyanto, Anugerah; Kato, Seizo; Maruyama, Naoki

    For solving decision problems in electric generation planning, a matrix operation based deterministic quantitative model called the Distance Based Approach (DBA) has been proposed for comparing the technical-economical and environmental features of various electric power plants. The customized computer code is developed to evaluate the overall function of alternative energy systems from the performance pattern corresponding to the selected energy attributes. For the purpose of exploring the applicability and the effectiveness of the proposed model, the model is applied to decision problems concerning the selection of energy sources for power generation in Japan. The set of nine energy alternatives includes conventional and new energy technologies of oil fired-, natural gas fired-, coal fired-, nuclear power, hydropower, geothermal, solar photovoltaic, wind power and solar thermal plants. Also, a set of criteria for optimized selection includes five areas of concern; energy economy, energy security, environmental protection, socio-economic development and technological aspects for electric power generation. The result will be a ranking of alternative sources of energy based on the Euclidean composite distance of each alternative to the designated optimal source of energy.

  14. Evaluation of UV-radiation induced singlet oxygen generation potential of selected drugs.

    PubMed

    Pandey, R; Mehrotra, S; Ray, R S; Joshi, P C; Hans, R K

    2002-05-01

    Photosensitization reaction of drugs leading to the formation of reactive oxygen species under ultraviolet radiation (UVR) can cause tissue injury, resulting in damage to various cellular macromolecules. The aim of this study was to determine the singlet oxygen generation potential of some commonly used antibiotics so that due precautions can be exercised to minimize their photosensitizing action and oxidative stress potential. The selected antibiotics were examined for their ability to produce singlet oxygen (1O2) under artificial UVA (320-400 nm). Singlet oxygen generation of various screened antibiotics under UVA is of the following order: Nalidixic acid > Amphotericin-B > Cephradine > Cefazolin > Nafcillin > Cephalothin > Ampicillin > Cephalexin > Puromycin > Kanamycin > Lincomycin > Tetracycline > Nystatin > Gentamicin sulphate. Nalidixic acid, the most potent generator of 1O2 among the screened antibiotics, was selected to carry out further studies. Certain specific quenchers of 1O2 such as beta-carotene, 1,4-diazabicyclo[2.2.2] octane (DABCO), and sodium azide (NaN3) accorded significant inhibition in the production of 1O2. The results suggest that precautions are necessary to avoid ultraviolet radiation after the intake of photoreactive drugs, especially in tropical countries such as India. These findings are significant because UVB radiation is reportedly increasing on earth surface in part due to depletion of stratospheric ozone layer. The selected drugs are commonly used for the treatment of various diseases. Thus, the synergistic action of both can lead to undesirable phototoxic responses.

  15. Synaptic Mechanisms Generating Orientation Selectivity in the ON Pathway of the Rabbit Retina

    PubMed Central

    Venkataramani, Sowmya

    2016-01-01

    Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input. SIGNIFICANCE STATEMENT A core goal for visual neuroscientists is to understand how neural circuits at each stage of the visual system extract and encode features from the visual scene. This study documents a novel type of orientation-selective ganglion cell in the retina and shows that the receptive field structure is remarkably similar to that of simple cells in primary visual cortex. However, the data indicate that, unlike in the cortex, orientation selectivity in the retina depends on the activity of

  16. Increased survival of western corn rootworm on transgenic corn within three generations of on-plant greenhouse selection

    PubMed Central

    Meihls, Lisa N.; Higdon, Matthew L.; Siegfried, Blair D.; Miller, Nicholas J.; Sappington, Thomas W.; Ellersieck, Mark R.; Spencer, Terence A.; Hibbard, Bruce E.

    2008-01-01

    To delay evolution of insect resistance to transgenic crops producing Bacillus thuringiensis (Bt) toxins, nearby “refuges” of host plants not producing Bt toxins are required in many regions. Such refuges are expected to be most effective in slowing resistance when the toxin concentration in Bt crops is high enough to kill all or nearly all insects heterozygous for resistance. However, Bt corn, Zea mays, introduced recently does not meet this “high-dose” criterion for control of western corn rootworm (WCR), Diabrotica virgifera virgifera. A greenhouse method of rearing WCR on transgenic corn expressing the Cry3Bb1 protein was used in which approximately 25% of previously unexposed larvae survived relative to isoline survival (compared to 1–4% in the field). After three generations of full larval rearing on Bt corn (Constant-exposure colony), WCR larval survival was equivalent on Bt corn and isoline corn in greenhouse trials, and the LC50 was 22-fold greater for the Constant-exposure colony than for the Control colony in diet bioassays with Cry3Bb1 protein on artificial diet. After six generations of greenhouse selection, the ratio of larval recovery on Bt corn to isoline corn in the field was 11.7-fold greater for the Constant-exposure colony than the Control colony. Removal from selection for six generations did not decrease survival on Bt corn in the greenhouse. The results suggest that rapid response to selection is possible in the absence of mating with unexposed beetles, emphasizing the importance of effective refuges for resistance management. PMID:19047626

  17. Harmonic signal generation and frequency upconversion using selective sideband Brillouin amplification in single-mode fiber.

    PubMed

    Lee, Kwang-Hyun; Choi, Woo-Young

    2007-06-15

    Harmonic signal generation and frequency upconversion at millimeter-wave bands are experimentally demonstrated by using selective sideband Brillouin amplification induced by stimulated Brillouin scattering in a single-mode fiber. The harmonic signals and frequency upconverted signals are simultaneously generated by the beating of optical sidebands, one of which is Brillouin amplified. By using this method, we successfully demonstrate generation of third-harmonic millimeter waves at 32.55 GHz with f(LO) of 10.85 GHz and upconversion of 10 Mbps quadrature-shift keyed data at f(IF) of 1.55 GHz into a 30 GHz band with more than 17 dB RF power gain.

  18. Temperature Programmed Desorption of Quench-condensed Krypton and Acetone in Air; Selective Concentration of Ultra-trace Gas Components.

    PubMed

    Suzuki, Taku T; Sakaguchi, Isao

    2016-01-01

    Selective concentration of ultra-trace components in air-like gases has an important application in analyzing volatile organic compounds in the gas. In the present study, we examined quench-condensation of the sample gas on a ZnO substrate below 50 K followed by temperature programmed desorption (TPD) (low temperature TPD) as a selective gas concentration technique. We studied two specific gases in the normal air; krypton as an inert gas and acetone as a reactive gas. We evaluated the relationship between the operating condition of low temperature TPD and the lowest detection limit. In the case of krypton, we observed the selective concentration by exposing at 6 K followed by thermal desorption at about 60 K. On the other hand, no selectivity appeared for acetone although trace acetone was successfully concentrated. This is likely due to the solvent effect by a major component in the air, which is suggested to be water. We suggest that pre-condensation to remove the water component may improve the selectivity in the trace acetone analysis by low temperature TPD.

  19. Temperature Programmed Desorption of Quench-condensed Krypton and Acetone in Air; Selective Concentration of Ultra-trace Gas Components.

    PubMed

    Suzuki, Taku T; Sakaguchi, Isao

    2016-01-01

    Selective concentration of ultra-trace components in air-like gases has an important application in analyzing volatile organic compounds in the gas. In the present study, we examined quench-condensation of the sample gas on a ZnO substrate below 50 K followed by temperature programmed desorption (TPD) (low temperature TPD) as a selective gas concentration technique. We studied two specific gases in the normal air; krypton as an inert gas and acetone as a reactive gas. We evaluated the relationship between the operating condition of low temperature TPD and the lowest detection limit. In the case of krypton, we observed the selective concentration by exposing at 6 K followed by thermal desorption at about 60 K. On the other hand, no selectivity appeared for acetone although trace acetone was successfully concentrated. This is likely due to the solvent effect by a major component in the air, which is suggested to be water. We suggest that pre-condensation to remove the water component may improve the selectivity in the trace acetone analysis by low temperature TPD. PMID:27063719

  20. The hydrophilicity vs. ion interaction selectivity plot revisited: The effect of mobile phase pH and buffer concentration on hydrophilic interaction liquid chromatography selectivity behavior.

    PubMed

    Iverson, Chad D; Gu, Xinyun; Lucy, Charles A

    2016-08-01

    This work systematically investigates the selectivity changes on many HILIC phases from w(w)pH 3.7-6.8, at 5 and 25mM buffer concentrations. Hydrophilicity (kcytosine/kuracil) vs. ion interaction (kBTMA/kuracil) selectivity plots developed by Ibrahim et al. (J. Chromatogr. A 1260 (2012) 126-131) are used to investigate the effect of mobile phase changes on the selectivity of 18 HILIC columns from various classes. "Selectivity change plots" focus on the change in hydrophilicity and ion interaction that the columns exhibit upon changing mobile phase conditions. In general, the selectivity behavior of most HILIC columns is dominated by silanol activity. Minimal changes in selectivity are observed upon changing pH between w(w)pH 5 and 6.8. However, a reduction in ionic interaction is observed when the buffer concentration is increased at w(w)pH≥5.0 due to ionic shielding. Reduction of the w(w)pH to<5.0 results in decreasing cation exchange activity due to silanol protonation. Under all eluent conditions, the majority of phases show little change in their hydrophilicity.

  1. Strain Selection for Generation of O-Antigen-Based Glycoconjugate Vaccines against Invasive Nontyphoidal Salmonella Disease

    PubMed Central

    Saul, Allan; MacLennan, Calman A.; Micoli, Francesca; Rondini, Simona

    2015-01-01

    Nontyphoidal Salmonellae, principally S. Typhimurium and S. Enteritidis, are a major cause of invasive bloodstream infections in sub-Saharan Africa with no vaccine currently available. Conjugation of lipopolysaccharide O-antigen to a carrier protein constitutes a promising vaccination strategy. Here we describe a rational process to select the most appropriate isolates of Salmonella as source of O-antigen for developing a bivalent glycoconjugate vaccine. We screened a library of 30 S. Typhimurium and 21 S. Enteritidis in order to identify the most suitable strains for large scale O-antigen production and generation of conjugate vaccines. Initial screening was based on growth characteristics, safety profile of the isolates, O-antigen production, and O-antigen characteristics in terms of molecular size, O-acetylation and glucosylation level and position, as determined by phenol sulfuric assay, NMR, HPLC-SEC and HPAEC-PAD. Three animal isolates for each serovar were identified and used to synthesize candidate glycoconjugate vaccines, using CRM197 as carrier protein. The immunogenicity of these conjugates and the functional activity of the induced antibodies was investigated by ELISA, serum bactericidal assay and flow cytometry. S. Typhimurium O-antigen showed high structural diversity, including O-acetylation of rhamnose in a Malawian invasive strain generating a specific immunodominant epitope. S. Typhimurium conjugates provoked an anti-O-antigen response primarily against the O:5 determinant. O-antigen from S. Enteritidis was structurally more homogeneous than from S. Typhimurium, and no idiosyncratic antibody responses were detected for the S. Enteritidis conjugates. Of the three initially selected isolates, two S. Typhimurium (1418 and 2189) and two S. Enteritidis (502 and 618) strains generated glycoconjugates able to induce high specific antibody levels with high breadth of serovar-specific strain coverage, and were selected for use in vaccine production. The

  2. Strain Selection for Generation of O-Antigen-Based Glycoconjugate Vaccines against Invasive Nontyphoidal Salmonella Disease.

    PubMed

    Lanzilao, Luisa; Stefanetti, Giuseppe; Saul, Allan; MacLennan, Calman A; Micoli, Francesca; Rondini, Simona

    2015-01-01

    Nontyphoidal Salmonellae, principally S. Typhimurium and S. Enteritidis, are a major cause of invasive bloodstream infections in sub-Saharan Africa with no vaccine currently available. Conjugation of lipopolysaccharide O-antigen to a carrier protein constitutes a promising vaccination strategy. Here we describe a rational process to select the most appropriate isolates of Salmonella as source of O-antigen for developing a bivalent glycoconjugate vaccine. We screened a library of 30 S. Typhimurium and 21 S. Enteritidis in order to identify the most suitable strains for large scale O-antigen production and generation of conjugate vaccines. Initial screening was based on growth characteristics, safety profile of the isolates, O-antigen production, and O-antigen characteristics in terms of molecular size, O-acetylation and glucosylation level and position, as determined by phenol sulfuric assay, NMR, HPLC-SEC and HPAEC-PAD. Three animal isolates for each serovar were identified and used to synthesize candidate glycoconjugate vaccines, using CRM197 as carrier protein. The immunogenicity of these conjugates and the functional activity of the induced antibodies was investigated by ELISA, serum bactericidal assay and flow cytometry. S. Typhimurium O-antigen showed high structural diversity, including O-acetylation of rhamnose in a Malawian invasive strain generating a specific immunodominant epitope. S. Typhimurium conjugates provoked an anti-O-antigen response primarily against the O:5 determinant. O-antigen from S. Enteritidis was structurally more homogeneous than from S. Typhimurium, and no idiosyncratic antibody responses were detected for the S. Enteritidis conjugates. Of the three initially selected isolates, two S. Typhimurium (1418 and 2189) and two S. Enteritidis (502 and 618) strains generated glycoconjugates able to induce high specific antibody levels with high breadth of serovar-specific strain coverage, and were selected for use in vaccine production. The

  3. 40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each...

  4. 40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each...

  5. 40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each...

  6. 40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each...

  7. 40 CFR 761.308 - Sample selection by random number generation on any two-dimensional square grid.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... generation on any two-dimensional square grid. 761.308 Section 761.308 Protection of Environment... § 761.79(b)(3) § 761.308 Sample selection by random number generation on any two-dimensional square... area created in accordance with paragraph (a) of this section, select two random numbers: one each...

  8. Cycle Evaluations of Reversible Chemical Reactions for Solar Thermochemical Energy Storage in Support of Concentrating Solar Power Generation Systems

    SciTech Connect

    Krishnan, Shankar; Palo, Daniel R.; Wegeng, Robert S.

    2010-07-25

    The production and storage of thermochemical energy is a possible route to increase capacity factors and reduce the Levelized Cost of Electricity from concentrated solar power generation systems. In this paper, we present the results of cycle evaluations for various thermochemical cycles, including a well-documented ammonia closed-cycle along with open- and closed-cycle versions of hydrocarbon chemical reactions. Among the available reversible hydrocarbon chemical reactions, catalytic reforming-methanation cycles are considered; specifically, various methane-steam reforming cycles are compared to the ammonia cycle. In some cases, the production of an intermediate chemical, methanol, is also included with some benefit being realized. The best case, based on overall power generation efficiency and overall plant capacity factor, was found to be an open cycle including methane-steam reforming, using concentrated solar energy to increase the chemical energy content of the reacting stream, followed by combustion to generate heat for the heat engine.

  9. ModelMage: a tool for automatic model generation, selection and management.

    PubMed

    Flöttmann, Max; Schaber, Jörg; Hoops, Stephan; Klipp, Edda; Mendes, Pedro

    2008-01-01

    Mathematical modeling of biological systems usually involves implementing, simulating, and discriminating several candidate models that represent alternative hypotheses. Generating and managing these candidate models is a tedious and difficult task and can easily lead to errors. ModelMage is a tool that facilitates management of candidate models. It is designed for the easy and rapid development, generation, simulation, and discrimination of candidate models. The main idea of the program is to automatically create a defined set of model alternatives from a single master model. The user provides only one SBML-model and a set of directives from which the candidate models are created by leaving out species, modifiers or reactions. After generating models the software can automatically fit all these models to the data and provides a ranking for model selection, in case data is available. In contrast to other model generation programs, ModelMage aims at generating only a limited set of models that the user can precisely define. ModelMage uses COPASI as a simulation and optimization engine. Thus, all simulation and optimization features of COPASI are readily incorporated. ModelMage can be downloaded from http://sysbio.molgen.mpg.de/modelmage and is distributed as free software. PMID:19425122

  10. Patients treated with first-generation HCV protease inhibitors exhibit high ribavirin concentrations.

    PubMed

    Bodeau, Sandra; Nguyen-Khac, Eric; Solas, Caroline; Bennis, Youssef; Capron, Dominique; Duverlie, Gilles; Brochot, Etienne

    2015-05-01

    Anemia is a well-known RBV-related event in HCV therapy which is exacerbated by the addition of telaprevir and boceprevir. This retrospective study evaluated and compared ribavirin exposure and parameters able to influence hemoglobin decrease in a large population of patients treated with dual or triple therapy. Patients on triple therapy had higher ribavirin concentrations at week 12 of treatment (3460 ng/mL vs. 1843 ng/mL; P < .0001). An association was also observed between week 12 eGFR and ribavirin concentration only for patients on triple therapy (P = .002). The proportion of patients with a  >20 mL/min/1.73 m(2) decrease in eGFR at week 12 was higher among patients on triple therapy: 32%, 14%, and 5% for boceprevir, telaprevir, and dual therapy, respectively (P = .025 and .026). No correlation was observed between boceprevir and telaprevir concentrations and hemoglobin or eGFR decrease. Exacerbation of anemia in patients on triple therapy is related to higher ribavirin concentrations. We provide an explanation for this increase in plasma RBV concentration. Triple therapy with PEG-IFN, RBV, and telaprevir or boceprevir will remain the only HCV treatment option for many patients. Our data show that the RBV dose can be decreased while maintaining adequate plasma concentrations and reducing anemia. PMID:25535910

  11. Variations in suspended sediment and associated trace element concentrations in selected riverine cross sections

    USGS Publications Warehouse

    Horowltz, A.J.

    1990-01-01

    Detailed sampling and subsequent analyses of riverine suspended sediment obtained from six rivers in the United States indicate substantial differences in suspended sediment concentrations and possibly in some associated trace elements, depending on whether depth- and width-integrated, point, or pumping samples are used. In addition, the data from time-series, depth-integrated sampling indicate that there can be substantial short-term (on the order of 20-30 min) spatial and/or temporal variations in suspended-sediment concentrations. Despite this, major element concentrations are remarkably stable both spatially and temporally. Trace element concentrations are generally stable; however, some spatial and temporal variations may occur.

  12. Revealing mechanisms of selective, concentration-dependent potentials of 4-hydroxy-2-nonenal to induce apoptosis in cancer cells through inactivation of membrane-associated catalase.

    PubMed

    Bauer, Georg; Zarkovic, Neven

    2015-04-01

    Tumor cells generate extracellular superoxide anions and are protected against superoxide anion-mediated intercellular apoptosis-inducing signaling by the expression of membrane-associated catalase. 4-Hydroxy-2-nonenal (4-HNE), a versatile second messenger generated during lipid peroxidation, has been shown to induce apoptosis selectively in malignant cells. The findings described in this paper reveal the strong, concentration-dependent potential of 4-HNE to specifically inactivate extracellular catalase of tumor cells both indirectly and directly and to consequently trigger apoptosis in malignant cells through superoxide anion-mediated intercellular apoptosis-inducing signaling. Namely, 4-HNE caused apoptosis selectively in NOX1-expressing tumor cells through inactivation of their membrane-associated catalase, thus reactivating subsequent intercellular signaling through the NO/peroxynitrite and HOCl pathways, followed by the mitochondrial pathway of apoptosis. Concentrations of 4-HNE of 1.2 µM and higher directly inactivated membrane-associated catalase of tumor cells, whereas at lower concentrations, 4-HNE triggered a complex amplificatory pathway based on initial singlet oxygen formation through H2O2 and peroxynitrite interaction. Singlet-oxygen-dependent activation of the FAS receptor and caspase-8 increased superoxide anion generation by NOX1 and amplification of singlet oxygen generation, which allowed singlet-oxygen-dependent inactivation of catalase. 4-HNE and singlet oxygen cooperate in complex autoamplificatory loops during this process. The finding of these novel anticancer pathways may be useful for understanding the role of 4-HNE in the control of malignant cells and for the optimization of ROS-dependent therapeutic approaches including antioxidant treatments.

  13. The isoforms generated by alternative translation initiation adopt similar conformation in the selectivity filter in TREK-2.

    PubMed

    Zhuo, Ren-Gong; Peng, Peng; Liu, Xiao-Yan; Zhang, Shu-Zhuo; Xu, Jiang-Ping; Zheng, Jian-Quan; Wei, Xiao-Li; Ma, Xiao-Yun

    2015-12-01

    TREK-2 (TWIK-related K(+) channel-2), a member of two-pore domain potassium (K2P) channel family, tunes cellular excitability via conducting leak or background currents. In TREK-2, the isoforms generated by alternative translation initiation (ATI) mechanism exhibit large divergence in unitary conductance, but similar in selectivity to K(+). Up to now, the structural basis for this similarity in ion selectivity is unknown. Here, we report that externally applied Ba(2+) inhibits the currents of TREK-2 in a concentration- and time-dependent manner. The blocking effect is blunted by elevated extracellular K(+) or mutation of S4 K(+) binding site, which suggests that the inhibitory mechanism of Ba(2+) is due to its competitive docking properties within the selectivity filter (SF). Next, we demonstrate that all the ATI isoforms exhibit analogous behaviors upon the application of Ba(2+) and alteration of extracellular pH (pHo), which acts on the outer position of the SF. These results strongly support the notion that all the ATI isoforms of TREK-2 possess resembled SF conformation in S4 site and the position defined by pHo, which implicates that neither the role of N-terminus (Nt) nor the unitary conductance is associated with SF conformation. Our findings might help to understand the detail gating mechanism of TREK-2 and K2P channels. PMID:26271386

  14. Background concentrations of metals in soils from selected regions in the State of Washington

    USGS Publications Warehouse

    Ames, K.C.; Prych, E.A.

    1995-01-01

    Soil samples from 60 sites in the State of Washington were collected and analyzed to determine the magnitude and variability of background concen- trations of metals in soils of the State. Samples were collected in areas that were relatively undisturbed by human activity from the most pre- dominant soils in 12 different regions that are representative of large areas of Washington State. Concentrations of metals were determined by five different laboratory methods. Concentrations of mercury and nickel determined by both the total and total-recoverable methods displayed the greatest variability, followed by chromium and copper determined by the total-recoverable method. Concentrations of other metals, such as aluminum and barium determined by the total method, varied less. Most metals concentrations were found to be more nearly log-normally than normally distributed. Total metals concentrations were not significantly different among the different regions. However, total-recoverable metals concentrations were not as similar among different regions. Cluster analysis revealed that sampling sites in three regions encompassing the Puget Sound could be regrouped to form two new regions and sites in three regions in south-central and southeastern Washington State could also be regrouped into two new regions. Concentrations for 7 of 11 total-recoverable metals correlated with total metals concentrations. Concen- trations of six total metals also correlated positively with organic carbon. Total-recoverable metals concentrations did not correlate with either organic carbon or particle size. Concentrations of metals determined by the leaching methods did not correlate with total or total-recoverable metals concentrations, nor did they correlate with organic carbon or particle size.

  15. Body mass index, gestational weight gain and fatty acid concentrations during pregnancy: the Generation R Study.

    PubMed

    Vidakovic, Aleksandra Jelena; Jaddoe, Vincent W V; Gishti, Olta; Felix, Janine F; Williams, Michelle A; Hofman, Albert; Demmelmair, Hans; Koletzko, Berthold; Tiemeier, Henning; Gaillard, Romy

    2015-11-01

    Obesity during pregnancy may be correlated with an adverse nutritional status affecting pregnancy and offspring outcomes. We examined the associations of prepregnancy body mass index and gestational weight gain with plasma fatty acid concentrations in mid-pregnancy. This study was embedded in a population-based prospective cohort study among 5636 women. We obtained prepregnancy body mass index and maximum weight gain during pregnancy by questionnaires. We measured concentrations of saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), n-3 polyunsaturated fatty acid (n-3 PUFA) and n-6 polyunsaturated fatty acid (n-6 PUFA) at a median gestational age of 20.5 (95% range 17.1-24.9) weeks. We used multivariate linear regression models. As compared to normal weight women, obese women had higher total SFA concentrations [difference: 0.10 standard deviation (SD) (95% Confidence Interval (CI) 0, 0.19)] and lower total n-3 PUFA concentrations [difference: - 0.11 SD (95% CI - 0.20, - 0.02)]. As compared to women with sufficient gestational weight gain, those with excessive gestational weight gain had higher SFA concentrations [difference: 0.16 SD (95% CI 0.08, 0.25)], MUFA concentrations [difference: 0.16 SD (95% CI 0.08, 0.24)] and n-6 PUFA concentrations [difference: 0.12 SD (95% CI 0.04, 0.21)]. These results were not materially affected by adjustment for maternal characteristics. Our results suggest that obesity and excessive weight gain during pregnancy are associated with an adverse fatty acids profile. Further studies are needed to assess causality and direction of the observed associations.

  16. On selection of primary modes for generation of strong internally resonant second harmonics in plate

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Chillara, Vamshi Krishna; Lissenden, Cliff J.

    2013-09-01

    The selection of primary shear-horizontal (SH) and Rayleigh-Lamb (RL) ultrasonic wave modes that generate cumulative second harmonics in homogeneous isotropic plates is analyzed by theoretical modeling. Selection criteria include: internal resonance (synchronism and nonzero power flux), group velocity matching, and excitability/receivability. The power flux, group velocity matching, and excitability are tabulated for the SH and RL internal resonance points. The analysis indicates that SH waves can generate cumulative symmetric RL secondary wave fields. Laboratory experiments on aluminum plates demonstrate that excitation of the SH3 primary mode generates the s4 secondary RL mode and that the secondary wave field amplitude increases linearly with propagation distance. Simple magnetostrictive transducers were used to excite the primary SH wave and to receive the SH and RL wave signals. Reception of these wave modes having orthogonal polarizations was achieved by simply reorienting the electrical coil. The experiment was complicated by the presence of a nonplanar primary wavefront, however finite element simulations were able to clarify the experimental results.

  17. Theoretical Analyses and Experimental Investigations of Selective Carbothermal Reactions of Vanadium-Bearing Titanomagnetite Concentrates for Preparation of Iron-Based Wear-Resistant Material

    NASA Astrophysics Data System (ADS)

    Zhang, Guangming; Feng, Keqin; Yue, Huifang

    2016-09-01

    Based on FACTSage® software, this paper focuses on the thermodynamic calculations of selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates for preparing iron-based wear-resistant material directly from vanadium-bearing titanomagnetite concentrates. The calculations show that it was most likely to generate metallic iron, titanium carbide and vanadium carbide among all possible carbothermal reactions of vanadium-bearing titanomagnetite concentrates in a vacuum of 10 Pa. The equilibrium composition calculations indicate that Fe3O4 can be reduced to metallic iron by carbon above 400°C, FeTiO3 can be converted into TiC by carbon above 800°C and V2O5 can be converted into VC by carbon above 600°C in a vacuum of 10 Pa. The investigations demonstrated that the percentage of ferrous oxides reduced to metallic iron was about 96%, the conversion percentage of FeTiO3 into TiC was about 75% and the conversion percentage of V2O5 into VC was about 94% after the selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates at 1300°C for 3 h in a vacuum of 10 Pa.

  18. Theoretical Analyses and Experimental Investigations of Selective Carbothermal Reactions of Vanadium-Bearing Titanomagnetite Concentrates for Preparation of Iron-Based Wear-Resistant Material

    NASA Astrophysics Data System (ADS)

    Zhang, Guangming; Feng, Keqin; Yue, Huifang

    2016-07-01

    Based on FACTSage® software, this paper focuses on the thermodynamic calculations of selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates for preparing iron-based wear-resistant material directly from vanadium-bearing titanomagnetite concentrates. The calculations show that it was most likely to generate metallic iron, titanium carbide and vanadium carbide among all possible carbothermal reactions of vanadium-bearing titanomagnetite concentrates in a vacuum of 10 Pa. The equilibrium composition calculations indicate that Fe3O4 can be reduced to metallic iron by carbon above 400°C, FeTiO3 can be converted into TiC by carbon above 800°C and V2O5 can be converted into VC by carbon above 600°C in a vacuum of 10 Pa. The investigations demonstrated that the percentage of ferrous oxides reduced to metallic iron was about 96%, the conversion percentage of FeTiO3 into TiC was about 75% and the conversion percentage of V2O5 into VC was about 94% after the selective carbothermal reactions of vanadium-bearing titanomagnetite concentrates at 1300°C for 3 h in a vacuum of 10 Pa.

  19. Concentrative uptake of cyclic ADP-ribose generated by BST-1+ stroma stimulates proliferation of human hematopoietic progenitors.

    PubMed

    Podestà, Marina; Benvenuto, Federica; Pitto, Anna; Figari, Osvaldo; Bacigalupo, Andrea; Bruzzone, Santina; Guida, Lucrezia; Franco, Luisa; Paleari, Laura; Bodrato, Nicoletta; Usai, Cesare; De Flora, Antonio; Zocchi, Elena

    2005-02-18

    Cyclic ADP-ribose (cADPR) is an intracellular calcium mobilizer generated from NAD(+) by the ADP-ribosyl cyclases CD38 and BST-1. cADPR, both exogenously added and paracrinally produced by a CD38(+) feeder layer, has recently been demonstrated to stimulate the in vitro proliferation of human hemopoietic progenitors (HP) and also the in vivo expansion of hemopoietic stem cells. The low density of BST-1 expression on bone marrow (BM) stromal cells and the low specific activity of the enzyme made it unclear whether cADPR generation by a BST-1(+) stroma could stimulate HP proliferation in the BM microenvironment. We developed and characterized two BST-1(+) stromal cell lines, expressing an ectocellular cyclase activity similar to that of BST-1(+) human mesenchymal stem cells, the precursors of BM stromal cells. Long term co-culture of cord blood-derived HP over these BST-1(+) feeders determined their expansion. Influx of paracrinally generated cADPR into clonogenic HP was mediated by a concentrative, nitrobenzylthioinosine- and dipyridamole-inhibitable nucleoside transporter, this providing a possible explanation to the effectiveness of the hormone-like concentrations of the cyclic nucleotide measured in the medium conditioned by BST-1(+) feeders. These results suggest that the BST-1-catalyzed generation of extracellular cADPR, followed by the concentrative uptake of the cyclic nucleotide by HP, may be physiologically relevant in normal hemopoiesis.

  20. Temperature and concentration fields in a generator integrated to single stage heat transformer using Water/Carrol mixture

    NASA Astrophysics Data System (ADS)

    Gómez-Arias, E.; Ibarra-Bahena, J.; Velazquez-Avelar, L.; Romero, R. J.; Rodríguez-Martínez, A.; Montiel-González, M.

    2014-12-01

    The generator is the starter device of single stage heat transformer ( SSHT) and its characteristics have main effects on the overall efficiency of this kind of absorption machines. This article reports a study of the generation of steam and changes in the concentration of the working solution (Water/Carrol mixture) into a plate heat exchanger as a function of its horizontal and vertical position by gravity effect. It is considered the analysis of six experimental tests; two were evaluated in a plate heat exchanger in a horizontal position and four in a vertical position (90 degree inclination). The generation of steam and increased concentration of the working solution are more sensitive to the vertical position of exchanger than in horizontal position. The results of numerical-experimental analysis indicates that a heat exchanger in horizontal position, the steam generation and the change in the concentration of the working solution occurring in the middle of the plate (or at greater distance depending to the thermodynamic conditions) and instantly in vertical position (at the input of the plate).

  1. PI3K isoform-selective inhibitors: next-generation targeted cancer therapies

    PubMed Central

    Wang, Xiang; Ding, Jian; Meng, Ling-hua

    2015-01-01

    The pivotal roles of phosphatidylinositol 3-kinases (PI3Ks) in human cancers have inspired active development of small molecules to inhibit these lipid kinases. However, the first-generation pan-PI3K and dual-PI3K/mTOR inhibitors have encountered problems in clinical trials, with limited efficacies as a monotherapeutic agent as well as a relatively high rate of side effects. It is increasingly recognized that different PI3K isoforms play non-redundant roles in particular tumor types, which has prompted the development of isoform-selective inhibitors for pre-selected patients with the aim for improving efficacy while decreasing undesirable side effects. The success of PI3K isoform-selective inhibitors is represented by CAL101 (Idelalisib), a first-in-class PI3Kδ-selective small-molecule inhibitor that has been approved by the FDA for the treatment of chronic lymphocytic leukemia, indolent B-cell non-Hodgkin's lymphoma and relapsed small lymphocytic lymphoma. Inhibitors targeting other PI3K isoforms are also being extensively developed. This review focuses on the recent progress in development of PI3K isoform-selective inhibitors for cancer therapy. A deeper understanding of the action modes of novel PI3K isoform-selective inhibitors will provide valuable information to further validate the concept of targeting specific PI3K isoforms, while the identification of biomarkers to stratify patients who are likely to benefit from the therapy will be essential for the success of these agents. PMID:26364801

  2. Selective Ligand Recognition by a Diversity-Generating Retroelement Variable Protein

    PubMed Central

    Miller, Jason L; Coq, Johanne Le; Hodes, Asher; Barbalat, Roman; Miller, Jeff F; Ghosh, Partho

    2008-01-01

    Diversity-generating retroelements (DGRs) recognize novel ligands through massive protein sequence variation, a property shared uniquely with the adaptive immune response. Little is known about how recognition is achieved by DGR variable proteins. Here, we present the structure of the Bordetella bacteriophage DGR variable protein major tropism determinant (Mtd) bound to the receptor pertactin, revealing remarkable adaptability in the static binding sites of Mtd. Despite large dissimilarities in ligand binding mode, principles underlying selective recognition were strikingly conserved between Mtd and immunoreceptors. Central to this was the differential amplification of binding strengths by avidity (i.e., multivalency), which not only relaxed the demand for optimal complementarity between Mtd and pertactin but also enhanced distinctions among binding events to provide selectivity. A quantitatively similar balance between complementarity and avidity was observed for Bordetella bacteriophage DGR as occurs in the immune system, suggesting that variable repertoires operate under a narrow set of conditions to recognize novel ligands. PMID:18532877

  3. Selective ligand recognition by a diversity-generating retroelement variable protein.

    PubMed

    Miller, Jason L; Le Coq, Johanne; Hodes, Asher; Barbalat, Roman; Miller, Jeff F; Ghosh, Partho

    2008-06-01

    Diversity-generating retroelements (DGRs) recognize novel ligands through massive protein sequence variation, a property shared uniquely with the adaptive immune response. Little is known about how recognition is achieved by DGR variable proteins. Here, we present the structure of the Bordetella bacteriophage DGR variable protein major tropism determinant (Mtd) bound to the receptor pertactin, revealing remarkable adaptability in the static binding sites of Mtd. Despite large dissimilarities in ligand binding mode, principles underlying selective recognition were strikingly conserved between Mtd and immunoreceptors. Central to this was the differential amplification of binding strengths by avidity (i.e., multivalency), which not only relaxed the demand for optimal complementarity between Mtd and pertactin but also enhanced distinctions among binding events to provide selectivity. A quantitatively similar balance between complementarity and avidity was observed for Bordetella bacteriophage DGR as occurs in the immune system, suggesting that variable repertoires operate under a narrow set of conditions to recognize novel ligands.

  4. Effect of an ozone-generating air-purifying device on reducing concentrations of formaldehyde in air

    SciTech Connect

    Esswein, E.J.; Boeniger, M.F.

    1994-02-01

    Formaldehyde, an air contaminant found in many indoor air investigations, poses distinct occupational exposure hazards in certain job categories (e.g., mortuary science) but is also of concern when found or suspected in office buildings and homes. A variety of air-purifying devices (APDs) are currently available or marketed for application to reduce or remove concentrations of a variety of indoor air pollutants through the use of ozone as a chemical oxidant. An investigation was conducted to determine if concentrations of formaldehyde similar to those found in industrial hygiene evaluations of funeral homes could be reduced with the use of an ozone-generating APD. An ozone-generating APD was placed in an exposure chamber and formaldehyde-containing embalming solution was allowed to evaporate naturally, creating peak and mean chamber concentrations of 2.5 and 1.3 ppm, respectively. Continuous-reading instruments were used to sample for formaldehyde and ozone. Active sampling methods were also used to sample simultaneously for formaldehyde and a possible reactant product, formic acid. Triplicate measurements were made in each of three evaluations: formaldehyde alone, ozone alone, and formaldehyde and ozone combined. Concentrations of formaldehyde were virtually identical with and without 0.5 ppm ozone. No reduction in formaldehyde concentration was found during a 90-minute evaluation using ozone at this concentration with peak and average concentrations of approximately 2.5 and 1.3 ppm formaldehyde, respectively. The results of this investigation suggest that the use of ozone is ineffective in reducing concentrations of formaldehyde. Because ozone has demonstrated health hazards, and is a regulated air contaminant in both the occupational and ambient environment, the use of ozone as an air purification agent in indoor air does not seem warranted. 25 refs., 5 figs., 4 tabs.

  5. Determination of Uranium Metal Concentration in Irradiated Fuel Storage Basin Sludge Using Selective Dissolution

    SciTech Connect

    Delegard, Calvin H.; Sinkov, Sergey I.; Chenault, Jeffrey W.; Schmidt, Andrew J.; Welsh, Terri L.; Pool, Karl N.

    2014-03-01

    Uranium metal corroding in water-saturated sludges now held in the US Department of Energy Hanford Site K West irradiated fuel storage basin can create hazardous hydrogen atmospheres during handling, immobilization, or subsequent transport and storage. Knowledge of uranium metal concentration in sludge thus is essential to safe sludge management and process design, requiring an expeditious routine analytical method to detect uranium metal concentrations as low as 0.03 wt% in sludge even in the presence of 30 wt% or higher total uranium concentrations.

  6. Wavelength-selective orbital-angular-momentum beam generation using MEMS tunable Fabry-Perot filter.

    PubMed

    Paul, Sujoy; Lyubopytov, Vladimir S; Schumann, Martin F; Cesar, Julijan; Chipouline, Arkadi; Wegener, Martin; Küppers, Franko

    2016-07-15

    We demonstrate an on-chip device capable of wavelength-selective generation of vortex beams, which is realized by a spiral phase plate integrated onto a microelectromechanical system (MEMS) tunable filter. This vortex MEMS filter, being capable of functioning simultaneously in both wavelength and orbital-angular-momentum (OAM) domains at the 1550 nm wavelength regime, is considered as a compact, robust, and cost-effective solution for simultaneous OAM- and wavelength-division multiplexed optical communications. The experimental OAM spectra for azimuthal orders 1, 2, and 3 show an OAM state purity >92% across a wavelength range of more than 30 nm. PMID:27420507

  7. Multilayer mirror with enhanced spectral selectivity for the next generation extreme ultraviolet lithography

    SciTech Connect

    Medvedev, V. V. Kruijs, R. W. E. van de; Yakshin, A. E.; Novikova, N. N.; Krivtsun, V. M.; Louis, E.; Bijkerk, F.; Yakunin, A. M.

    2013-11-25

    We have demonstrated a hybrid extreme ultraviolet (EUV) multilayer mirror for 6.x nm radiation that provides selective suppression for infrared (IR) radiation. The mirror consists of an IR-transparent LaN∕B multilayer stack which is used as EUV-reflective coating and antireflective (AR) coating to suppress IR. The AR coating can be optimized to suppress CO{sub 2} laser radiation at the wavelength of 10.6 μm, which is of interest for application in next-generation EUV lithography systems.

  8. Wavelength-selective orbital-angular-momentum beam generation using MEMS tunable Fabry-Perot filter.

    PubMed

    Paul, Sujoy; Lyubopytov, Vladimir S; Schumann, Martin F; Cesar, Julijan; Chipouline, Arkadi; Wegener, Martin; Küppers, Franko

    2016-07-15

    We demonstrate an on-chip device capable of wavelength-selective generation of vortex beams, which is realized by a spiral phase plate integrated onto a microelectromechanical system (MEMS) tunable filter. This vortex MEMS filter, being capable of functioning simultaneously in both wavelength and orbital-angular-momentum (OAM) domains at the 1550 nm wavelength regime, is considered as a compact, robust, and cost-effective solution for simultaneous OAM- and wavelength-division multiplexed optical communications. The experimental OAM spectra for azimuthal orders 1, 2, and 3 show an OAM state purity >92% across a wavelength range of more than 30 nm.

  9. Advances in Concentrating Solar Power Collectors: Mirrors and Solar Selective Coatings

    SciTech Connect

    Kenendy, C. E.

    2007-10-10

    The intention is to explore the feasibility of depositing the coating by lower-cost methods and to perform a rigorous cost analysis after a viable high-temperature solar-selective coating is demonstrated by e-beam.

  10. Effects of intraruminal infusions of sodium salts on selection of hay and concentrate foods by sheep.

    PubMed

    Azahan, E A; Forbes, J M

    1992-04-01

    Infusion of salts of short-chain fatty acids into the rumen of sheep depresses food intake but the relative importance of the effect of the acids and of osmolality are not fully understood. Three experiments were carried out in which sodium acetate (NaAc) and sodium chloride (NaCl) were infused for 3 h at 4 mM/min and compared with water controls. The effects on the intakes of a concentrate food and hay were examined to study the effect of osmotic and acid manipulation of the rumen on dietary choice. In the first experiment the foods were continuously available while in the second and third the foods were given for 3 min at 1.5-h intervals. Salt infusions depressed concentrate intake without significant effect on the intake of hay. The effect of NaAc tended to be greater than that of NaCl and persisted after the end of infusion. The weight of concentrate eaten during the 3-min tests was significantly and negatively related to both acetate and sodium concentrations in rumen fluid. The weight of hay eaten was negatively related to concentrate intake. The results demonstrate that the treatments imposed had a differential effect on intake, only depressing that of the concentrate food. They also suggest that, as NaAc has a greater effect than NaCl, the influence on feeding is due both to the osmotic load and the acid effect.

  11. Evaluation of Diazinon and Chlorpyrifos Concentrations and Loads, and other Pesticide Concentrations, at Selected Sites in the San Joaquin Valley, California, April to August, 2001

    USGS Publications Warehouse

    Domagalski, Joseph L.; Munday, Cathy

    2003-01-01

    Twelve sites in the San Joaquin Valley of California were monitored weekly during the growing and irrigation season of 2001 for a total of 51 pesticides and pesticide degradation products, with primary interest on the concentration, load, and basin yield of organophosphorus insecticides, especially diazinon and chlorpyrifos. Diazinon was detected frequently, up to 100 percent of the time, at many of the sampling sites, but with generally low concentrations. For all sites, 75 percent of all measured diazinon concentrations were less than 0.02 mg/L, and 90 percent of all measured diazinon concentrations were less than 0.06 mg/L. The highest diazinon concentrations were measured in samples from two west-side tributaries to the San Joaquin River, Orestimba Creek, and Del Puerto Creek. The median concentration of chlorpyrifos was at or less than the laboratory reporting limit (0.005 mg/L) for most sites with the exceptions of two tributaries to the San Joaquin River: Orestimba Creek and the Tuolumne River. For all sites, 75 percent of all measured chlorpyrifos concentrations were less than 0.03 mg/L and 90 percent of all measured chlorpyrifos concentrations were less than 0.07 mg/L. The total load of diazinon out of the basin was just over 7 kilograms, which accounted for about 0.17 percent of the total agricultural applications. The diazinon load from the monitored upstream tributaries accounted for about 50 percent of the load at the mouth of the San Joaquin River. The streamflow from the selected monitored tributaries accounted for about 83 percent of the streamflow at the mouth of the San Joaquin River. The total load of chlorpyrifos out of the basin was 3.75 kilograms, and this accounted for approximately 0.007 percent of the total amount applied. Other pesticides that were frequently detected during this study included herbicides such as metolachlor, simazine, and trifluralin, and insecticides such as carbaryl, carbofuran, and propargite. At Orestimba Creek, DDE

  12. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and Adults in California

    PubMed Central

    Wu, Xiangmei (May); Bennett, Deborah H.; Calafat, Antonia M.; Kato, Kayoko; Strynar, Mark; Andersen, Erik; Moran, Rebecca E.; Tancredi, Daniel J.; Tulve, Nicolle S.; Hertz-Picciotto, Irva

    2016-01-01

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual’s exposure over a one-year period. The study population included three demographic groups: young children (2–8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26–0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68–0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend

  13. Serum concentrations of perfluorinated compounds (PFC) among selected populations of children and adults in California.

    PubMed

    Wu, Xiangmei May; Bennett, Deborah H; Calafat, Antonia M; Kato, Kayoko; Strynar, Mark; Andersen, Erik; Moran, Rebecca E; Tancredi, Daniel J; Tulve, Nicolle S; Hertz-Picciotto, Irva

    2015-01-01

    Perfluorinated compounds (PFCs) have been widely used in industrial applications and consumer products. Their persistent nature and potential health impacts are of concern. Given the high cost of collecting serum samples, this study is to understand whether we can quantify PFC serum concentrations using factors extracted from questionnaire responses and indirect measurements, and whether a single serum measurement can be used to classify an individual's exposure over a one-year period. The study population included three demographic groups: young children (2-8 years old) (N=67), parents of young children (<55 years old) (N=90), and older adults (>55 years old) (N=59). PFC serum concentrations, house dust concentrations, and questionnaires were collected. The geometric mean of perfluorooctane sulfonic acid (PFOS) was highest for the older adults. In contrast, the geometric mean of perfluorooctanoic acid (PFOA) was highest for children. Serum concentrations of the parent and the child from the same family were moderately correlated (Spearman correlation (r)=0.26-0.79, p<0.05), indicating common sources within a family. For adults, age, having occupational exposure or having used fire extinguisher, frequencies of consuming butter/margarine, pork, canned meat entrées, tuna and white fish, freshwater fish, and whether they ate microwave popcorn were significantly positively associated with serum concentrations of individual PFCs. For children, residential dust concentrations, frequency of wearing waterproof clothes, frequency of having canned fish, hotdogs, chicken nuggets, French fries, and chips, and whether they ate microwave popcorn were significant positive predictors of individual PFC serum concentrations. In addition, the serum concentrations collected in a subset of young children (N=20) and the parents (N=42) one year later were strongly correlated (r=0.68-0.98, p<0.001) with the levels measured at the first visits, but showed a decreasing trend. Children had

  14. Concentric Circular Grating Generated by the Patterning Trapping of Nanoparticles in an Optofluidic Chip.

    PubMed

    Dai, Hailang; Cao, Zhuangqi; Wang, Yuxing; Li, Honggen; Sang, Minghuang; Yuan, Wen; Chen, Fan; Chen, Xianfeng

    2016-01-01

    Due to the field enhancement effect of the hollow-core metal-cladded optical waveguide chip, massive nanoparticles in a solvent are effectively trapped via exciting ultrahigh order modes. A concentric ring structure of the trapped nanoparticles is obtained since the excited modes are omnidirectional at small incident angle. During the process of solvent evaporation, the nanoparticles remain well trapped since the excitation condition of the optical modes is still valid, and a concentric circular grating consisting of deposited nanoparticles can be produced by this approach. Experiments via scanning electron microscopy, atomic force microscopy and diffraction of a probe laser confirmed the above hypothesis. This technique provides an alternative strategy to enable effective trapping of dielectric particles with low-intensity nonfocused illumination, and a better understanding of the correlation between the guided modes in an optical waveguide and the nanoparticles in a solvent. PMID:27550743

  15. Concentric Circular Grating Generated by the Patterning Trapping of Nanoparticles in an Optofluidic Chip

    PubMed Central

    Dai, Hailang; Cao, Zhuangqi; Wang, Yuxing; Li, Honggen; Sang, Minghuang; Yuan, Wen; Chen, Fan; Chen, Xianfeng

    2016-01-01

    Due to the field enhancement effect of the hollow-core metal-cladded optical waveguide chip, massive nanoparticles in a solvent are effectively trapped via exciting ultrahigh order modes. A concentric ring structure of the trapped nanoparticles is obtained since the excited modes are omnidirectional at small incident angle. During the process of solvent evaporation, the nanoparticles remain well trapped since the excitation condition of the optical modes is still valid, and a concentric circular grating consisting of deposited nanoparticles can be produced by this approach. Experiments via scanning electron microscopy, atomic force microscopy and diffraction of a probe laser confirmed the above hypothesis. This technique provides an alternative strategy to enable effective trapping of dielectric particles with low-intensity nonfocused illumination, and a better understanding of the correlation between the guided modes in an optical waveguide and the nanoparticles in a solvent. PMID:27550743

  16. Concentric Circular Grating Generated by the Patterning Trapping of Nanoparticles in an Optofluidic Chip.

    PubMed

    Dai, Hailang; Cao, Zhuangqi; Wang, Yuxing; Li, Honggen; Sang, Minghuang; Yuan, Wen; Chen, Fan; Chen, Xianfeng

    2016-08-23

    Due to the field enhancement effect of the hollow-core metal-cladded optical waveguide chip, massive nanoparticles in a solvent are effectively trapped via exciting ultrahigh order modes. A concentric ring structure of the trapped nanoparticles is obtained since the excited modes are omnidirectional at small incident angle. During the process of solvent evaporation, the nanoparticles remain well trapped since the excitation condition of the optical modes is still valid, and a concentric circular grating consisting of deposited nanoparticles can be produced by this approach. Experiments via scanning electron microscopy, atomic force microscopy and diffraction of a probe laser confirmed the above hypothesis. This technique provides an alternative strategy to enable effective trapping of dielectric particles with low-intensity nonfocused illumination, and a better understanding of the correlation between the guided modes in an optical waveguide and the nanoparticles in a solvent.

  17. Mineral concentration in selected native temperate grasses with potential use as biofuel feedstock.

    PubMed

    El-Nashaar, H M; Griffith, S M; Steiner, J J; Banowetz, G M

    2009-07-01

    Stands of native grasses along roadways, in buffer strips, riparian zones and grass prairies have potential utility as feedstock for bioenergy production. The sustainability of harvesting these stands is reliant, in part, on knowledge of the mineral concentration of the harvested grasses because removal of mineral nutrients such as phosphorus (P) and potassium (K) can impact subsequent biomass production and ecosystem services associated with these stands. Mineral content of biomass, particularly that of silicon (Si), chlorine (Cl), and sulfur (S) also impacts thermochemical conversion approaches that convert grasses into bioproducts. This study quantified Cl, S, Si, P and K in Bromus marginatus, Elymus glaucus, Poa secunda, Pseudoroegneria, Elymus lanceolatus, Elymus trachycaulus, Leymus cinereus, Leymus triticoides, and Pseudoroegneria spicata collected at three growth developmental stages from four plant introduction stations located in the western US. Differences (P< or =0.05) in mineral concentrations were associated with developmental stage, species, and location. Variability was greatest in Si concentrations which ranged from 1847 to 28620 mg kg(-1), similar to those recorded in other grasses. Variability in Cl and S concentrations also occurred, but at less magnitude than that of Si. Concentrations of P and K, two mineral fertilizer components, varied approximately threefold among these grasses. Differences in mineral concentrations among these grasses were not completely dependent upon soil mineral content. Long-term evaluations of available soil mineral concentrations under contrasting management practices are needed to quantify how local conditions impact mineral cycling, and in turn, the sustainability of harvesting these stands. The data presented here establish baselines for these species in locations subject to contrasting environmental and microbiological conditions that affect mineral cycling and availability.

  18. Mineral concentration in selected native temperate grasses with potential use as biofuel feedstock.

    PubMed

    El-Nashaar, H M; Griffith, S M; Steiner, J J; Banowetz, G M

    2009-07-01

    Stands of native grasses along roadways, in buffer strips, riparian zones and grass prairies have potential utility as feedstock for bioenergy production. The sustainability of harvesting these stands is reliant, in part, on knowledge of the mineral concentration of the harvested grasses because removal of mineral nutrients such as phosphorus (P) and potassium (K) can impact subsequent biomass production and ecosystem services associated with these stands. Mineral content of biomass, particularly that of silicon (Si), chlorine (Cl), and sulfur (S) also impacts thermochemical conversion approaches that convert grasses into bioproducts. This study quantified Cl, S, Si, P and K in Bromus marginatus, Elymus glaucus, Poa secunda, Pseudoroegneria, Elymus lanceolatus, Elymus trachycaulus, Leymus cinereus, Leymus triticoides, and Pseudoroegneria spicata collected at three growth developmental stages from four plant introduction stations located in the western US. Differences (P< or =0.05) in mineral concentrations were associated with developmental stage, species, and location. Variability was greatest in Si concentrations which ranged from 1847 to 28620 mg kg(-1), similar to those recorded in other grasses. Variability in Cl and S concentrations also occurred, but at less magnitude than that of Si. Concentrations of P and K, two mineral fertilizer components, varied approximately threefold among these grasses. Differences in mineral concentrations among these grasses were not completely dependent upon soil mineral content. Long-term evaluations of available soil mineral concentrations under contrasting management practices are needed to quantify how local conditions impact mineral cycling, and in turn, the sustainability of harvesting these stands. The data presented here establish baselines for these species in locations subject to contrasting environmental and microbiological conditions that affect mineral cycling and availability. PMID:19329307

  19. EMG activity and voluntary activation during knee-extensor concentric torque generation.

    PubMed

    Babault, Nicolas; Pousson, Michel; Michaut, Anne; Ballay, Yves; Hoecke, Jacques Van

    2002-04-01

    This study was designed to re-examine and compare the neural drive of the knee extensors during isokinetic concentric muscular actions by means of the twitch interpolation technique (activation level, AL) and surface electromyographic (EMG) recordings (root mean square, RMS). Torque, AL and RMS amplitudes of three knee extensors and one knee flexor were measured in nine subjects during maximal and sub-maximal voluntary contractions, performed under concentric (60 degrees.s(-1) and 120 degrees.s(-1); Con60 and Con120, respectively) and isometric (Iso) conditions. Mean (SD) maximal voluntary torque was significantly lower ( P<0.01) during concentric contractions [Con60: 208.6 (26.8) Nm and Con120: 184.7 (26.4) Nm] compared with isometric contractions [327.4 (52.0) Nm]. A significantly lower AL ( P<0.05) was recorded during Con60 [80.9 (8.8)%] compared with Iso [87.9 (5.1)%] and Con120 [88.2 (6.6)%] maximal contractions. Simultaneously, a lower knee extensor average RMS amplitudes (av.RMS) was measured during Con60 maximal contractions compared with Iso and Con120 maximal contractions. The antagonist biceps femoris RMS values were not different between maximal Iso, Con60 and Con120 contractions. During sub-maximal voluntary contractions, the RMS/torque relationships were similar whatever the muscle considered (vastus lateralis, vastus medialis or rectus femoris) and the AL/av.RMS relationships did not reveal any noticeable differences between each contractile condition. The results of the present study indicate that av.RMS and AL describe similarly the neural drive during maximal and sub-maximal efforts and indicate that during maximal voluntary efforts, neural drive is dependent upon concentric angular velocity (up to 120 degrees.s(-1)). Thus, our results suggest that when applying different contractile conditions, the torque output is regulated via complex interactions between intrinsic muscular properties and the neural drive.

  20. Trends in suspended-sediment concentration at selected stream sites in Kansas, 1970-2002

    USGS Publications Warehouse

    Putnam, James E.; Pope, Larry M.

    2003-01-01

    Knowledge of erosion, transport, and deposition of sediment relative to streams and impoundments is important to those involved directly or indirectly in the development and management of water resources. Monitoring the quantity of sediment in streams and impoundments is important because: (1) sediment may degrade the water quality of streams for such uses as municipal water supply, (2) sediment is detrimental to the health of some species of aquatic animals and plants, and (3) accumulation of sediment in water-supply impoundments decreases the amount of storage and, therefore, water available for users. One of the objectives of the Kansas Water Plan is to reduce the amount of sediment in Kansas streams by 2010. During the last 30 years, millions of dollars have been spent in Kansas watersheds to reduce sediment transport to streams. Because the last evaluation of trends in suspended-sediment concentrations in Kansas was completed in 1985, 14 sediment sampling sites that represent 10 of the 12 major river basins in Kansas were reestablished in 2000. The purpose of this report is to present the results of time-trend analyses at the reestablished sediment data-collection sites for the period of about 1970?2002 and to evaluate changes in the watersheds that may explain the trends. Time-trend tests for 13 of 14 sediment sampling sites in Kansas for the period from about 1970 to 2002 indicated that 3 of the 13 sites tested had statistically significant decreasing suspended-sediment concentrations; however, only 2 sites, Walnut River at Winfield and Elk River at Elk Falls, had trends that were statistically significant at the 0.05 probability level. Increasing suspended-sediment concentrations were indicated at three sites although none were statistically significant at the 0.05 probability level. Samples from five of the six sampling sites located upstream from reservoirs indicated decreasing suspended-sediment concentrations. Watershed impoundments located in the

  1. Mode selective generation of guided waves by systematic optimization of the interfacial shear stress profile

    NASA Astrophysics Data System (ADS)

    Yazdanpanah Moghadam, Peyman; Quaegebeur, Nicolas; Masson, Patrice

    2015-01-01

    Piezoelectric transducers are commonly used in structural health monitoring systems to generate and measure ultrasonic guided waves (GWs) by applying interfacial shear and normal stresses to the host structure. In most cases, in order to perform damage detection, advanced signal processing techniques are required, since a minimum of two dispersive modes are propagating in the host structure. In this paper, a systematic approach for mode selection is proposed by optimizing the interfacial shear stress profile applied to the host structure, representing the first step of a global optimization of selective mode actuator design. This approach has the potential of reducing the complexity of signal processing tools as the number of propagating modes could be reduced. Using the superposition principle, an analytical method is first developed for GWs excitation by a finite number of uniform segments, each contributing with a given elementary shear stress profile. Based on this, cost functions are defined in order to minimize the undesired modes and amplify the selected mode and the optimization problem is solved with a parallel genetic algorithm optimization framework. Advantages of this method over more conventional transducers tuning approaches are that (1) the shear stress can be explicitly optimized to both excite one mode and suppress other undesired modes, (2) the size of the excitation area is not constrained and mode-selective excitation is still possible even if excitation width is smaller than all excited wavelengths, and (3) the selectivity is increased and the bandwidth extended. The complexity of the optimal shear stress profile obtained is shown considering two cost functions with various optimal excitation widths and number of segments. Results illustrate that the desired mode (A0 or S0) can be excited dominantly over other modes up to a wave power ratio of 1010 using an optimal shear stress profile.

  2. [Serum concentration of selected neoplasm markers: CA15-3, TPS and CEA in women with diagnosed breast benign disease].

    PubMed

    Kochańska-Dziurowicz, A; Pasich, R; Stanjek, A; Gaweł-Szostek, V; Jankowski, T

    2000-09-01

    The aim of the study was the assessment of serum concentrations of selected neoplasmatic markers: CA15-3, TPS and CEA in women with established diagnosis of benign breast disease (BBD) using hormone replacement therapy (HRT) for average 3 years. 120 women with BBD were divided to 2 groups: HRT-users (n1 = 24) and HRT-non-users (n2 = 96). 31 healthy, regularly menstruating, age-matched women served as control group. Concentrations of all markers were measured with immunoradiometric methods. In all groups serum concentrations of measured markers were within normal range. We conclude that hormone replacement therapy has no influence on serum concentrations of CA15-3, TPS and CEA.

  3. Selective Concentration of Ultra-trace Acetone in the Air by Cryogenic Temperature Programmed Desorption (cryo-TPD).

    PubMed

    Suzuki, Taku T; Sakaguchi, Isao

    2016-01-01

    A gas analytical technique with compact size, low cost, sufficient sensitivity, and excellent reproducibility is required in many fields including exhaled breath analysis for medical monitoring. In the present study, we examined selective acetone concentration by quench condensation at cryogenic temperature followed by temperature programmed desorption (cryogenic temperature programmed desorption (cryo-TPD)) for possible applications to breath analysis for medical monitoring. The essence of cryo-TPD is rough mass selection by thermal desorption followed by quantification of certain species using mass spectrometry. The performance of cryo-TPD was investigated in the acetone concentration range below 1 × 10(-6) volume fraction (1 ppmv). It was found that acetone is selectively quench-condensed on a tungsten substrate at 50 K without the major components of air, such as N2 and O2. The concentrated acetone gas was obtained by the following thermal desorption at around 151 K. Under conditions of condensation for 1 min and pressure of 1 × 10(-2) Pa, the lowest limit of detection reached well below 10 × 10(-9) volume fraction (10 ppbv). The relationship between the cetone intensity of cryo-TPD and the acetone concentration in the gas was almost linear in the ppbv range. The separation of acetone and propanal using the fragmentation pattern, which have almost the identical molecular mass, was also demonstrated in the present study. PMID:27682397

  4. Characteristics of products generated by selective sintering and stereolithography rapid prototyping processes

    NASA Technical Reports Server (NTRS)

    Cariapa, Vikram

    1993-01-01

    The trend in the modern global economy towards free market policies has motivated companies to use rapid prototyping technologies to not only reduce product development cycle time but also to maintain their competitive edge. A rapid prototyping technology is one which combines computer aided design with computer controlled tracking of focussed high energy source (eg. lasers, heat) on modern ceramic powders, metallic powders, plastics or photosensitive liquid resins in order to produce prototypes or models. At present, except for the process of shape melting, most rapid prototyping processes generate products that are only dimensionally similar to those of the desired end product. There is an urgent need, therefore, to enhance the understanding of the characteristics of these processes in order to realize their potential for production. Currently, the commercial market is dominated by four rapid prototyping processes, namely selective laser sintering, stereolithography, fused deposition modelling and laminated object manufacturing. This phase of the research has focussed on the selective laser sintering and stereolithography rapid prototyping processes. A theoretical model for these processes is under development. Different rapid prototyping sites supplied test specimens (based on ASTM 638-84, Type I) that have been measured and tested to provide a data base on surface finish, dimensional variation and ultimate tensile strength. Further plans call for developing and verifying the theoretical models by carefully designed experiments. This will be a joint effort between NASA and other prototyping centers to generate a larger database, thus encouraging more widespread usage by product designers.

  5. Parallel Cascade Selection Molecular Dynamics (PaCS-MD) to generate conformational transition pathway.

    PubMed

    Harada, Ryuhei; Kitao, Akio

    2013-07-21

    Parallel Cascade Selection Molecular Dynamics (PaCS-MD) is proposed as a molecular simulation method to generate conformational transition pathway under the condition that a set of "reactant" and "product" structures is known a priori. In PaCS-MD, the cycle of short multiple independent molecular dynamics simulations and selection of the structures close to the product structure for the next cycle are repeated until the simulated structures move sufficiently close to the product. Folding of 10-residue mini-protein chignolin from the extended to native structures and open-close conformational transition of T4 lysozyme were investigated by PaCS-MD. In both cases, tens of cycles of 100-ps MD were sufficient to reach the product structures, indicating the efficient generation of conformational transition pathway in PaCS-MD with a series of conventional MD without additional external biases. Using the snapshots along the pathway as the initial coordinates, free energy landscapes were calculated by the combination with multiple independent umbrella samplings to statistically elucidate the conformational transition pathways.

  6. Axonal selection and myelin sheath generation in the central nervous system.

    PubMed

    Simons, Mikael; Lyons, David A

    2013-08-01

    The formation of myelin in the central nervous system is a multi-step process that involves coordinated cell-cell interactions and dramatic changes in plasma membrane architecture. First, oligodendrocytes send our numerous highly ramified processes to sample the axonal environment and decide which axon(s) to select for myelination. After this decision is made and individual axon to oligodendrocyte contact has been established, the exploratory process of the oligodendrocyte is converted into a flat sheath that spreads and winds along and around its associated axon to generate a multilayered membrane stack. By compaction of the opposing extracellular layers of membrane and extrusion of almost all cytoplasm from the intracellular domain of the sheath, the characteristic membrane-rich multi-lamellar structure of myelin is formed. Here we highlight recent advances in identifying biophysical and signalling based mechanisms that are involved in axonal selection and myelin sheath generation by oligodendrocytes. A thorough understanding of the mechanisms underlying these events is a prerequisite for the design of novel myelin repair strategies in demyelinating and dysmyelinating diseases.

  7. A review of metaphase chromosome image selection techniques for automatic karyotype generation.

    PubMed

    Arora, Tanvi; Dhir, Renu

    2016-08-01

    The karyotype is analyzed to detect the genetic abnormalities. It is generated by arranging the chromosomes after extracting them from the metaphase chromosome images. The chromosomes are non-rigid bodies that contain the genetic information of an individual. The metaphase chromosome image spread contains the chromosomes, but these chromosomes are not distinct bodies; they can either be individual chromosomes or be touching one another; they may be bent or even may be overlapping and thus forming a cluster of chromosomes. The extraction of chromosomes from these touching and overlapping chromosomes is a very tedious process. The segmentation of a random metaphase chromosome image may not give us correct and accurate results. Therefore, before taking up a metaphase chromosome image for analysis, it must be analyzed for the orientation of the chromosomes it contains. The various reported methods for metaphase chromosome image selection for automatic karyotype generation are compared in this paper. After analysis, it has been concluded that each metaphase chromosome image selection method has its advantages and disadvantages.

  8. Optimal selection of on-site generation with combined heat andpower applications

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris; Bailey, Owen; HamachiLaCommare, Kristina

    2004-11-30

    While demand for electricity continues to grow, expansion of the traditional electricity supply system, or macrogrid, is constrained and is unlikely to keep pace with the growing thirst western economies have for electricity. Furthermore, no compelling case has been made that perpetual improvement in the overall power quality and reliability (PQR)delivered is technically possible or economically desirable. An alternative path to providing high PQR for sensitive loads would generate close to them in microgrids, such as the Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid. Distributed generation would alleviate the pressure for endless improvement in macrogrid PQR and might allow the establishment of a sounder economically based level of universal grid service. Energy conversion from available fuels to electricity close to loads can also provide combined heat and power (CHP) opportunities that can significantly improve the economics of small-scale on-site power generation, especially in hot climates when the waste heat serves absorption cycle cooling equipment that displaces expensive on-peak electricity. An optimization model, the Distributed Energy Resources Customer Adoption Model (DER-CAM), developed at Berkeley Lab identifies the energy bill minimizing combination of on-site generation and heat recovery equipment for sites, given their electricity and heat requirements, the tariffs they face, and a menu of available equipment. DER-CAM is used to conduct a systemic energy analysis of a southern California naval base building and demonstrates atypical current economic on-site power opportunity. Results achieve cost reductions of about 15 percent with DER, depending on the tariff.Furthermore, almost all of the energy is provided on-site, indicating that modest cost savings can be achieved when the microgrid is free to select distributed generation and heat recovery equipment in order to minimize its over all costs.

  9. Technical report series: Concentrations of PCBs, DDTr, and selected metals in biota from Guntersville Reservoir

    SciTech Connect

    Dycus, D.L.; Lowery, D.R.

    1986-10-01

    The purpose was to determine if there was potential for human health risks from consumption of reservoir fish or if selected toxic substances might be impacting reservoir biota. Fillets from catfish (channel and blue) and largemouth bass were analyzed for the first purpose and whole gizzard shad, catfish livers, and turtle livers and fat were analyzed for the second. Results indicate largemouth bass should be safe for consumption based on low levels of tested contaminants. However, three of sixteen catfish samples contained PCB levels above the Food and Drug Administration (FDA) tolerance of 2.0 ..mu..g/g, and seven others contained levels sufficiently close to that value to warrant concern. DDT and its metabolites and selected metals were low in catfish except for chromium, nickel, and mercury in selected cases. Analyses on all sample types (those referenced above plus catfish livers and turtle fat and livers) indicated levels of metals were generally low and probably not individually impacting reservoir biota.

  10. Impact of mineral components and selected trace metals on ambient PM10 concentrations

    NASA Astrophysics Data System (ADS)

    Limbeck, Andreas; Handler, Markus; Puls, Christoph; Zbiral, Johannes; Bauer, Heidi; Puxbaum, Hans

    PM10 levels of the mineral components Si, Al, Fe, Ca, Mg and some trace metals were measured at three different sites in the urban area of Vienna (Austria). Observed trace metal concentrations varied between less than 0.1 ng m -3 (Cd) and approximately 200 ng m -3 (Zn), mineral components showed enhanced concentrations ranging from 0.01 μg m -3 (Ca) to 16.3 μg m -3 (Si). The contribution of the respective mineral oxides to PM10 mass concentrations accounted on average for 26.4 ± 16% (n = 1090) of the PM10 mass, with enhanced rates in spring and autumn (monthly averages of up to 40%) and decreased contributions in the cold season (monthly averages below 10%). The atmospheric occurrence of Al, Ti and Sr could be assigned to crustal sources, whereas for the elements Ba, Ca, Fe, Mg, Mn and V an increased contribution of non-crustal origin was observed. PM10 levels of As, Cd, Co, Cr, Cu, Ni, Pb, Sb, Sn and Zn were predominantly derived from man-made emissions. Intersite comparison indicated that urban PM10 mass concentrations and PM10 levels of As, Pb and Zn were predominantly influenced from the transport of aerosols from outside into the city, whereas for the elements Ba, Mg, Ca, Cu and Fe a distinctly increased impact of local emissions was observed. The contribution of these urban emissions to total PM10 concentrations was estimated by calculating the so-called "urban impact", which was found to be 32.7 ± 18% (n = 392) in the case of PM10 mass concentrations. The investigated elements accounted on average for 31.3 ± 19% (n = 392) of the observed PM10 mass increase. The mean values for the "urban impacts" of individual elements varied between 25.5% (As) and 77.0% (Ba).

  11. Cation Exchange Selectivity versus concentration of competing heavy metal cations (Pb2+,Zn2+) : case of Na-montmorillonite

    NASA Astrophysics Data System (ADS)

    Oueslati, W.; Mefath, M.; Ben Rhaiem, H.; Ben Haj Amara, A.

    2009-11-01

    Cation Exchange Selectivity (CES) for Wyoming montmorillonite was determined by equilibration of the clay with a mixed equinormal solution containing two competing cations (i.e. Pb2+, Zn2+). This paper aims at characterizing the structural change and selectivity of a Na-dioctahedral smectite (Wy-Na). The quantitative analysis of XRD patterns is achieved using an indirect method based on the comparison of XRD experimental patterns to calculated ones. Two reference samples were prepared by saturation with Pb2+ or Zn2+ (i.e. two heavy metal cations occurring in hold house trash). The resulting complexes were respectively labelled Wy-Pb and Wy-Zn. After that, the Wy-Na sample was dispersed in solutions containing 0.5Pb2+ and 0.5Zn2+ with different concentrations (from 10-2 N to 10-4 N) in order to understand the concentration effect on the selectivity process of the Na-montmorillonite. The XRD quantitative analysis shows that for low concentrations the d001 spacing value corresponds to Wy-Na complex, whereas for high concentrations the d001 spacing value can be attributed to the Wy-Zn and/or Wy-Pb. At low concentrations, the sample presents a homogeneous state and the cation exchange capacity is saturated with Na+ cation which is characterized by one water layer hydration state (1W). For high concentrations, interstratified hydration behavior appears and the clay has a tendency to exchange in minor contribution the Zn2+ cation and in major contribution Pb2+ cation characterized by a mixed hydration state between one (1W) and two water layers (2W).

  12. Sulfur Based Thermochemical Heat Storage for Baseload Concentrated Solar Power Generation

    SciTech Connect

    wong, bunsen

    2014-11-20

    This project investigates the engineering and economic feasibility of supplying baseload power using a concentrating solar power (CSP) plant integrated with sulfur based thermochemical heat storage. The technology stores high temperature solar heat in the chemical bonds of elemental sulfur. Energy is recovered as high temperature heat upon sulfur combustion. Extensive developmental and design work associated with sulfur dioxide (SO2) disproportionation and sulfuric acid (H2SO4) decomposition chemical reactions used in this technology had been carried out in the two completed phases of this project. The feasibility and economics of the proposed concept was demonstrated and determined.

  13. Selectivity and Mass Transfer Limitations in Pressure-Retarded Osmosis at High Concentrations and Increased Operating Pressures.

    PubMed

    Straub, Anthony P; Osuji, Chinedum O; Cath, Tzahi Y; Elimelech, Menachem

    2015-10-20

    Pressure-retarded osmosis (PRO) is a promising source of renewable energy when hypersaline brines and other high concentration solutions are used. However, membrane performance under conditions suitable for these solutions is poorly understood. In this work, we use a new method to characterize membranes under a variety of pressures and concentrations, including hydraulic pressures up to 48.3 bar and concentrations of up to 3 M NaCl. We find membrane selectivity decreases as the draw solution concentration is increased, with the salt permeability coefficient increasing by a factor of 2 when the draw concentration is changed from 0.6 to 3 M NaCl, even when the applied hydraulic pressure is maintained constant. Additionally, we find that significant pumping energy is required to overcome frictional pressure losses in the spacer-filled feed channel and achieve suitable mass transfer on the feed side of the membrane, especially at high operating pressures. For a meter-long module operating at 41 bar, we estimate feedwater will have to be pumped in at a pressure of at least 3 bar. Both the reduced selectivity and increased pumping energy requirements we observe in PRO will significantly diminish the obtainable net energy, highlighting important new challenges for development of systems utilizing hypersaline draw solutions.

  14. Life cycle assessment of fuel selection for power generation in Taiwan.

    PubMed

    Yang, Ying-Hsien; Lin, Sue-Jane; Lewis, Charles

    2007-11-01

    Life cycle assessment (LCA) was applied to performance data from 1997-2002 to evaluate the environmental impacts of the energy input, airborne emission, waterborne emission, and solid waste inventories for Taiwan's electric power plants. Eco-indicator 95 was used to compare the differences among the generation processes and fuel purification. To better understand the environmental trends related to Taiwan's electric power industry, three fuel scenarios were selected for LCA system analysis. Results indicate that there are differences in characteristic environmental impact among the 13 power plants. Scenario simulation provided a basis for minimizing environmental impacts from fuel selection targets. Fuel selection priority should be a gas-fired combined cycle substituted for a coal-fired steam turbine to be more environmentally friendly, particularly in the areas of the greenhouse effect, acidification, winter smog, and solid waste. Furthermore, based purely on economic and environmental criteria, it is recommended that the gas-fired combined cycle be substituted for the oil-fired steam turbine.

  15. Life cycle assessment of fuel selection for power generation in Taiwan.

    PubMed

    Yang, Ying-Hsien; Lin, Sue-Jane; Lewis, Charles

    2007-11-01

    Life cycle assessment (LCA) was applied to performance data from 1997-2002 to evaluate the environmental impacts of the energy input, airborne emission, waterborne emission, and solid waste inventories for Taiwan's electric power plants. Eco-indicator 95 was used to compare the differences among the generation processes and fuel purification. To better understand the environmental trends related to Taiwan's electric power industry, three fuel scenarios were selected for LCA system analysis. Results indicate that there are differences in characteristic environmental impact among the 13 power plants. Scenario simulation provided a basis for minimizing environmental impacts from fuel selection targets. Fuel selection priority should be a gas-fired combined cycle substituted for a coal-fired steam turbine to be more environmentally friendly, particularly in the areas of the greenhouse effect, acidification, winter smog, and solid waste. Furthermore, based purely on economic and environmental criteria, it is recommended that the gas-fired combined cycle be substituted for the oil-fired steam turbine. PMID:18069462

  16. Selective superoxide generation within mitochondria by the targeted redox cycler MitoParaquat.

    PubMed

    Robb, Ellen L; Gawel, Justyna M; Aksentijević, Dunja; Cochemé, Helena M; Stewart, Tessa S; Shchepinova, Maria M; Qiang, He; Prime, Tracy A; Bright, Thomas P; James, Andrew M; Shattock, Michael J; Senn, Hans M; Hartley, Richard C; Murphy, Michael P

    2015-12-01

    Superoxide is the proximal reactive oxygen species (ROS) produced by the mitochondrial respiratory chain and plays a major role in pathological oxidative stress and redox signaling. While there are tools to detect or decrease mitochondrial superoxide, none can rapidly and specifically increase superoxide production within the mitochondrial matrix. This lack impedes progress, making it challenging to assess accurately the roles of mitochondrial superoxide in cells and in vivo. To address this unmet need, we synthesized and characterized a mitochondria-targeted redox cycler, MitoParaquat (MitoPQ) that comprises a triphenylphosphonium lipophilic cation conjugated to the redox cycler paraquat. MitoPQ accumulates selectively in the mitochondrial matrix driven by the membrane potential. Within the matrix, MitoPQ produces superoxide by redox cycling at the flavin site of complex I, selectively increasing superoxide production within mitochondria. MitoPQ increased mitochondrial superoxide in isolated mitochondria and cells in culture ~a thousand-fold more effectively than untargeted paraquat. MitoPQ was also more toxic than paraquat in the isolated perfused heart and in Drosophila in vivo. MitoPQ enables the selective generation of superoxide within mitochondria and is a useful tool to investigate the many roles of mitochondrial superoxide in pathology and redox signaling in cells and in vivo.

  17. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part III: leucocyte activation: a new feature for platelet concentrates?

    PubMed

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. In this third article, we investigate the immune features of this biomaterial. During PRF processing, leucocytes could also secrete cytokines in reaction to the hemostatic and inflammatory phenomena artificially induced in the centrifuged tube. We therefore undertook to quantify 5 significant cell mediators within platelet poor plasma supernatant and PRF clot exudate serum: 3 proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha), an antiinflammatory cytokine (IL-4), and a key growth promoter of angiogenesis (VEGF). Our data are correlated with that obtained in plasma (nonactivated blood) and in sera (activated blood). These initial analyses revealed that PRF could be an immune regulation node with inflammation retrocontrol abilities. This concept could explain the reduction of postoperative infections when PRF is used as surgical additive.

  18. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part II: platelet-related biologic features.

    PubMed

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. In this second article, we investigate the platelet-associated features of this biomaterial. During PRF processing by centrifugation, platelets are activated and their massive degranulation implies a very significant cytokine release. Concentrated platelet-rich plasma platelet cytokines have already been quantified in many technologic configurations. To carry out a comparative study, we therefore undertook to quantify PDGF-BB, TGFbeta-1, and IGF-I within PPP (platelet-poor plasma) supernatant and PRF clot exudate serum. These initial analyses revealed that slow fibrin polymerization during PRF processing leads to the intrinsic incorporation of platelet cytokines and glycanic chains in the fibrin meshes. This result would imply that PRF, unlike the other platelet concentrates, would be able to progressively release cytokines during fibrin matrix remodeling; such a mechanism might explain the clinically observed healing properties of PRF.

  19. Development and characterization of a coronary polylactic acid stent prototype generated by selective laser melting.

    PubMed

    Flege, Christian; Vogt, Felix; Höges, Simon; Jauer, Lucas; Borinski, Mauricio; Schulte, Vera A; Hoffmann, Rainer; Poprawe, Reinhart; Meiners, Wilhelm; Jobmann, Monika; Wissenbach, Konrad; Blindt, Rüdiger

    2013-01-01

    In-stent restenosis is still an important issue and stent thrombosis is an unresolved risk after coronary intervention. Biodegradable stents would provide initial scaffolding of the stenosed segment and disappear subsequently. The additive manufacturing technology Selective Laser Melting (SLM) enables rapid, parallel, and raw material saving generation of complex 3- dimensional structures with extensive geometric freedom and is currently in use in orthopedic or dental applications. Here, SLM process parameters were adapted for poly-L-lactid acid (PLLA) and PLLA-co-poly-ε-caprolactone (PCL) powders to generate degradable coronary stent prototypes. Biocompatibility of both polymers was evidenced by assessment of cell morphology and of metabolic and adhesive activity at direct and indirect contact with human coronary artery smooth muscle cells, umbilical vein endothelial cells, and endothelial progenitor cells. γ-sterilization was demonstrated to guarantee safety of SLM-processed parts. From PLLA and PCL, stent prototypes were successfully generated and post-processing by spray- and dip-coating proved to thoroughly smoothen stent surfaces. In conclusion, for the first time, biodegradable polymers and the SLM technique were combined for the manufacturing of customized biodegradable coronary artery stent prototypes. SLM is advocated for the development of biodegradable coronary PLLA and PCL stents, potentially optimized for future bifurcation applications.

  20. Cold atmospheric plasma jet-generated RONS and their selective effects on normal and carcinoma cells

    PubMed Central

    Kim, Sun Ja; Chung, T. H.

    2016-01-01

    Cold atmospheric helium plasma jets were fabricated and utilized for plasma–cell interactions. The effect of operating parameters and jet design on the generation of specific reactive oxygen and nitrogen species (RONS) within cells and cellular response were investigated. It was found that plasma treatment induced the overproduction of RONS in various cancer cell lines selectively. The plasma under a relatively low applied voltage induced the detachment of cells, a reduction in cell viability, and apoptosis, while the plasma under higher applied voltage led to cellular necrosis in our case. To determine whether plasma-induced reactive oxygen species (ROS) generation occurs through interfering with mitochondria-related cellular response, we examined the plasma effects on ROS generation in both parental A549 cells and A549 ρ0 cells. It was observed that cancer cells were more susceptible to plasma-induced RONS (especially nitric oxide (NO) and nitrogen dioxide (NO2−) radicals) than normal cells, and consequently, plasma induced apoptotic cell responses mainly in cancer cells. PMID:26838306

  1. Cold atmospheric plasma jet-generated RONS and their selective effects on normal and carcinoma cells.

    PubMed

    Kim, Sun Ja; Chung, T H

    2016-01-01

    Cold atmospheric helium plasma jets were fabricated and utilized for plasma-cell interactions. The effect of operating parameters and jet design on the generation of specific reactive oxygen and nitrogen species (RONS) within cells and cellular response were investigated. It was found that plasma treatment induced the overproduction of RONS in various cancer cell lines selectively. The plasma under a relatively low applied voltage induced the detachment of cells, a reduction in cell viability, and apoptosis, while the plasma under higher applied voltage led to cellular necrosis in our case. To determine whether plasma-induced reactive oxygen species (ROS) generation occurs through interfering with mitochondria-related cellular response, we examined the plasma effects on ROS generation in both parental A549 cells and A549 ρ(0) cells. It was observed that cancer cells were more susceptible to plasma-induced RONS (especially nitric oxide (NO) and nitrogen dioxide (NO2(-)) radicals) than normal cells, and consequently, plasma induced apoptotic cell responses mainly in cancer cells.

  2. Generation of orthogonally selective bacterial riboswitches by targeted mutagenesis and in vivo screening.

    PubMed

    Vincent, Helen A; Robinson, Christopher J; Wu, Ming-Cheng; Dixon, Neil; Micklefield, Jason

    2014-01-01

    Riboswitches are naturally occurring RNA-based genetic switches that control gene expression in response to the binding of small-molecule ligands, typically through modulation of transcription or translation. Their simple mechanism of action and the expanding diversity of riboswitch classes make them attractive targets for the development of novel gene expression tools. The essential first step in realizing this potential is to generate artificial riboswitches that respond to nonnatural, synthetic ligands, thereby avoiding disruption of normal cellular function. Here we describe a strategy for engineering orthogonally selective riboswitches based on natural switches. The approach begins with saturation mutagenesis of the ligand-binding pocket of a naturally occurring riboswitch to generate a library of riboswitch mutants. These mutants are then screened in vivo against a synthetic compound library to identify functional riboswitch-ligand combinations. Promising riboswitch-ligand pairs are then further characterized both in vivo and in vitro. Using this method, a series of artificial riboswitches can be generated that are versatile synthetic biology tools for use in protein production, gene functional analysis, metabolic engineering, and other biotechnological applications. PMID:24549615

  3. RANK-ORDER-SELECTIVE NEURONS FORM A TEMPORAL BASIS SET FOR THE GENERATION OF MOTOR SEQUENCES

    PubMed Central

    Salinas, Emilio

    2009-01-01

    Many behaviors are composed of a series of elementary motor actions that must occur in a specific order, but the neuronal mechanisms by which such motor sequences are generated are poorly understood. In particular, if a sequence consists of a few motor actions, a primate can learn to replicate it from memory after practicing it for just a few trials. How do the motor and premotor areas of the brain assemble motor sequences so fast? The network model presented here reveals part of the solution to this problem. The model is based on experiments showing that, during the performance of motor sequences, some cortical neurons are always activated at specific times, regardless of which motor action is being executed. In the model, a population of such rank-order-selective (ROS) cells drives a layer of downstream motor neurons so that these generate specific movements at different times in different sequences. A key ingredient of the model is that the amplitude of the ROS responses must be modulated by sequence identity. Because of this modulation, which is consistent with experimental reports, the network is able not only to produce multiple sequences accurately but also to learn a new sequence with minimal changes in connectivity. The ROS neurons modulated by sequence identity thus serve as a basis set for constructing arbitrary sequences of motor responses downstream. The underlying mechanism is analogous to the mechanism described in parietal areas for generating coordinate transformations in the spatial domain. PMID:19357265

  4. Concentration selective hydration and phase states of hydroxyethyl cellulose (HEC) in aqueous solutions.

    PubMed

    Arfin, Najmul; Bohidar, H B

    2012-04-01

    Solution behaviour of hydroxyethyl cellulose (HEC) is reported in the polymer concentration range spanning over two decades (c=0.002-5% (w/v)). The results conclude the following: (i) dilute solution regime prevailed for c<0.2% (w/v), flexible HEC fibres of typical length ≈ 1 μm and persistence length ≈ 10 nm were found here, (ii) for 0.2concentration regimes. Cole-Cole plots revealed phase homogeneity and miscibility was limited to concentrations less than ~2% (w/v). For higher polymer concentrations, strong fibre-fibre interactions prevailed and samples became heterogeneous.

  5. Concentration polarization and second-kind electrokinetic instability at an ion-selective surface admitting normal flow

    NASA Astrophysics Data System (ADS)

    Khair, Aditya S.

    2011-07-01

    The passage of ionic current across a charge-selective surface has been studied for over a century and is relevant to well-established processes such as electrodialysis, electrodeposition, and electrochromatography. Recent years have witnessed a resurgence of interest in this subject, motivated by experiments demonstrating charge-selective transport of ions and solutes in nanofluidic devices. In this paper, we revisit and build upon the prototypical problem of one-dimensional ion transport across a flat ideally ion-selective surface, by examining the influence of imposed fluid flows on concentration polarization, over-limiting current, and second-kind (non-equilibrium) electro-osmotic instability at the surface. Specifically, we consider a simple model system of a cation-selective surface or membrane that admits a uniform fluid flow across itself. The membrane resides against a binary symmetric electrolyte, whose concentration is uniform in a "well-mixed" region at a prescribed distance from the membrane. A potential difference across the system drives an ionic current, leading to concentration polarization in the "unstirred layer" between the membrane and well-mixed bulk. The concentration polarization profile reflects a balance between advection of ions with the imposed "normal flow" and diffusion. The relative importance of these effects is parameterized by a Pećlet number Pe; notably, Pe is a signed quantity as the flow can be imposed toward or away from the membrane. An asymptotic analysis in the thin-Debye-layer limit reveals a significant impact of normal flow on concentration polarization and the advection-diffusion limiting current across the membrane. In particular, there exists a nonlinear concentration profile in the unstirred layer for non-zero Pe, in contrast to the familiar linear (diffusive) concentration polarization at Pe = 0. Next, we use matched asymptotic expansions to explore the structure of the unstirred layer at over-limiting currents

  6. Rotating night shift work, sleep quality, selected lifestyle factors and prolactin concentration in nurses and midwives.

    PubMed

    Bukowska, Agnieszka; Sobala, Wojciech; Peplonska, Beata

    2015-04-01

    The pattern of secretion of many hormones, including prolactin, is dependent on the circadian rhythm. Night shift work involves exposure to artificial light at night and sleep deficiency, which in turn can affect prolactin synthesis. The aim of this study was to evaluate a possible association between night shift work characteristics, sleep quality, lifestyle factors and prolactin concentration, using data from a cross-sectional study of nurses and midwives. A cross-sectional study was conducted among 327 nurses and midwives currently working on rotating night shifts, and 330 nurses and midwives working during the day (aged 40-60 years) (388 premenopausal and 269 postmenopausal). Information about night shift work characteristics, lifestyle, reproductive factors, sleep pattern and other covariates was collected through a face-to-face interview, and from a one-week work and sleep diary completed by the subjects. Weight and height were measured. Prolactin concentration was measured in the morning blood sample using the electrochemiluminesence immunoassay method. Associations were analyzed using linear regression models adjusted for important confounders. Analyses were carried out separately in pre- and postmenopausal women. None of the night shift work or sleep characteristics was significantly associated with prolactin concentration. Prolactin concentration was significantly (p < 0.05) inversely associated with smoking and time of blood sample collection. These results were consistent among both pre- and postmenopausal women. Nulliparity was significantly positively associated with prolactin among premenopausal women, but inversely among postmenopausal. Age was related to prolactin among postmenopausal women only. Our study indicates that rotating night shift work is not associated with prolactin concentration. Smoking, parity, time of blood collection and age among postmenopausal women were significant determinants of prolactin.

  7. II. Apples to apples A2: cluster selection functions for next-generation surveys

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Mei, S.; Bartlett, J. G.; Benítez, N.

    2016-10-01

    We present the cluster selection function for three of the largest next-generation stage-IV surveys in the optical and infrared: Euclid-Optimistic, Euclid-Pessimistic and the Large Synoptic Survey Telescope (LSST). To simulate these surveys, we use the realistic mock catalogues introduced in the first paper of this series. We detected galaxy clusters using the Bayesian Cluster Finder (BCF) in the mock catalogues. We then modeled and calibrated the total cluster stellar mass observable-theoretical mass (M^*_CL-M_h) relation using a power law model, including a possible redshift evolution term. We find a moderate scatter of σ _{M^*_CL | M_h} of 0.124, 0.135 and 0.136 dex for Euclid-Optimistic, Euclid-Pessimistic and LSST, respectively, comparable to other work over more limited ranges of redshift. Moreover, the three datasets are consistent with negligible evolution with redshift, in agreement with observational and simulation results in the literature. We find that Euclid-Optimistic will be able to detect clusters with >80% completeness and purity down to 8 × 1013h-1M⊙ up to z < 1. At higher redshifts, the same completeness and purity are obtained with the larger mass threshold of 2 × 1014h-1M⊙ up to z = 2. The Euclid-Pessimistic selection function has a similar shape with ˜10% higher mass limit. LSST shows ˜5% higher mass limit than Euclid-Optimistic up to z < 0.7 and increases afterwards, reaching values of 2 × 1014h-1M⊙ at z = 1.4. Similar selection functions with only 80% completeness threshold have been also computed. The complementarity of these results with selection functions for surveys in other bands is discussed.

  8. Determination of neutral carbon concentration in electron cyclotron resonance generated plasma discharges

    SciTech Connect

    Ene, A. B.; Lindner, P.; Stirn, R.; Schumacher, U.

    2007-12-15

    Carbon containing plasmas play an important role not only in plasma technology but also in thermonuclear fusion research. In order to understand and control the processes taking place in the plasma, the knowledge of the carbon ground state density is of major importance. It can be determined by absorption and emission spectroscopy. Detailed measurements were performed in the past to determine the silicon ground state density by means of spectroscopy of the self-absorbed spectral lines of the silicon ground state multiplet at 251 nm. The same procedure was applied for the determination of the carbon concentration, for which the carbon multiplet at 165 nm was analyzed and compared to a simulated spectrum. The ground state density was determined by two independent methods.

  9. Concentrations of selected trace elements in mineral and spring bottled waters on the Serbian market.

    PubMed

    Ristić, M; Popović, I; Pocajt, V; Antanasijević, D; Perić-Grujić, A

    2011-01-01

    Eight selected trace elements, which are generally included in regulations, were analyzed in 23 types of bottled waters. Ten mineral and seven spring bottled waters were from the Serbian market and six mineral bottled waters were obtained in different EU countries. For the purpose of comparison, selected tap waters were also analyzed. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the analysis of trace elements (arsenic, cadmium, copper, manganese, nickel, lead and antimony). Results were compared with the Serbian regulations for bottled water, EU regulations and guideline values set by the World Health Organization for drinking water. With few exceptions, the trace element levels of most bottled waters were below the guideline values. However, a higher content of antimony was observed in waters from polyethylene terephthalate (PET) containers, indicating a potential leaching of this element from the plastic packaging.

  10. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    NASA Astrophysics Data System (ADS)

    Nielsen, Christoffer P.; Bruus, Henrik

    2014-04-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in qualitative agreement with experimental results published in the literature. The analytical results are furthermore in agreement with direct numerical simulations. As part of the analysis, we find approximate solutions to the classical problem of pure salt transport across an ion-selective interface. These solutions provide closed-form expressions for the current-voltage characteristics, which include the overlimiting current due to the development of an extended space-charge region. Finally, we discuss how the addition of an acid or a base affects the transport properties of the system and thus provide predictions accessible to further experimental tests of the model.

  11. Discovery of XEN445: a potent and selective endothelial lipase inhibitor raises plasma HDL-cholesterol concentration in mice.

    PubMed

    Sun, Shaoyi; Dean, Richard; Jia, Qi; Zenova, Alla; Zhong, Jing; Grayson, Celene; Xie, Clark; Lindgren, Andrea; Samra, Pritpaul; Sojo, Luis; van Heek, Margaret; Lin, Linus; Percival, David; Fu, Jian-Min; Winther, Michael D; Zhang, Zaihui

    2013-12-15

    Endothelial lipase (EL) activity has been implicated in HDL metabolism and in atherosclerotic plaque development; inhibitors are proposed to be efficacious in the treatment of dyslipidemia related cardiovascular disease. We describe here the discovery of a novel class of anthranilic acids EL inhibitors. XEN445 (compound 13) was identified as a potent and selective EL inhibitor, that showed good ADME and PK properties, and demonstrated in vivo efficacy in raising plasma HDLc concentrations in mice. PMID:24211162

  12. Estimating volatile organic compound concentrations in selected microenvironments using time-activity and personal exposure data.

    PubMed

    Sexton, Ken; Mongin, Steven J; Adgate, John L; Pratt, Gregory C; Ramachandran, Gurumurthy; Stock, Thomas H; Morandi, Maria T

    2007-03-01

    Repeated measures of personal exposure to 14 volatile organic compounds (VOC) were obtained over 3 seasons for 70 healthy, nonsmoking adults living in Minneapolis-St. Paul. Matched data were also available for participants' time-activity patterns, and measured VOC concentrations outdoors in the community and indoors in residences. A novel modeling approach employing hierarchical Bayesian techniques was used to estimate VOC concentrations (posterior mode) and variability (credible intervals) in five microenvironments: (1) indoors at home; (2) indoors at work/school; (3) indoors in other locations; (4) outdoors in any location; and (5) in transit. Estimated concentrations tended to be highest in "other" indoor microenvironments (e.g., grocery stores, restaurants, shopping malls), intermediate in the indoor work/school and residential microenvironments, and lowest in the outside and in-transit microenvironments. Model estimates for all 14 VOC were reasonable approximations of measured median concentrations in the indoor residential microenvironment. The largest predicted contributor to cumulative (2-day) personal exposure for all 14 VOC was the indoor residential environment. Model-based results suggest that indoors-at-work/school and indoors-at-other-location microenvironments were the second or third largest contributors for all VOC, while the outside-in-any-location and in-transit microenvironments appeared to contribute negligibly to cumulative personal exposure. Results from a mixed-effects model indicate that being in or near a garage increased personal exposure to o-xylene, m/p-xylene, benzene, ethylbenzene, and toluene, and leaving windows and doors at home open for 6 h or more decreased personal exposure to 13 of 14 VOC, all except trichloroethylene.

  13. Total fume and metal concentrations during welding in selected factories in Jeddah, Saudi Arabia.

    PubMed

    Balkhyour, Mansour Ahmed; Goknil, Mohammad Khalid

    2010-07-01

    Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder's health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers' welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m(3) (Factory 1), 5.3 mg/m(3) (Factory 2), 11.3 mg/m(3) (Factory 3), 6.8 mg/m(3) (Factory 4), 4.7 mg/m(3) (Factory 5), and 3.0 mg/m(3) (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m(3)-0.477 mg/m(3), 0.001 mg/m(3)-0.080 mg/m(3) and 0.001 mg/m(3)-0.058 mg/m(3) respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems. PMID:20717553

  14. Concentration of selected trace elements and PCBs in sediments from the Adriatic Sea

    SciTech Connect

    Fowler, S W; Hamilton, T F; Coquery, M; Villeneuve, J-P; Horvat, M

    2000-07-26

    A broad baseline study of the levels and distributions of trace metals and PCB compounds in sediments has been undertaken. PCB concentrations in surface sediments reflect the source of these contaminates in the region. The highest PCB concentrations as Aroclor 1260 (approximately 10 ng g{sup -1}) were found in sediments near the outflow of the Po river. The lowest concentrations (1.5 ng g{sup -1} dry) were associated with the sediments from the Jabuka Pit in the Middle Adriatic. These values are quite similar to total PCBs (<1.0-17) measured in surface sediments sampled off the coast of Croatia in 1977-78. Thus, based on the limited amount of new data available, it appears that there has been little, if any, decrease in PCB loading in Adriatic sediments over the past 15 years. Downcore profiles of PCBs in sediment cores are also discussed from a pollution history standpoint. Likewise, total mercury in surface sediments was also highest at stations off the Po (403-499 ng g{sup -1} dry) and lowest (67-224 ng g{sup -1}) in the Jabuka Pit. In one core located just south of the Po outflow, total Hg concentrations at all depths were relatively high decreasing gradually from approximately 400 ng g{sup -1} in the top 4 cm to roughly 200 ng g{sup -1} at a depth of 32 cm. Using a {sup 210}Pb-derived sedimentation rate of 0.26 em Y{sup -1} for this station, it appears that anthropogenic inputs of mercury may have been responsible for the gradual increase in total mercury noted over the last 125 years.

  15. Total Fume and Metal Concentrations during Welding in Selected Factories in Jeddah, Saudi Arabia

    PubMed Central

    Balkhyour, Mansour Ahmed; Goknil, Mohammad Khalid

    2010-01-01

    Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder’s health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers’ welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m3 (Factory 1), 5.3 mg/m3 (Factory 2), 11.3 mg/m3 (Factory 3), 6.8 mg/m3 (Factory 4), 4.7 mg/m3 (Factory 5), and 3.0 mg/m3 (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m3–0.477 mg/m3, 0.001 mg/m3–0.080 mg/m3 and 0.001 mg/m3–0.058 mg/m3 respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems. PMID:20717553

  16. Total fume and metal concentrations during welding in selected factories in Jeddah, Saudi Arabia.

    PubMed

    Balkhyour, Mansour Ahmed; Goknil, Mohammad Khalid

    2010-07-01

    Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder's health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers' welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m(3) (Factory 1), 5.3 mg/m(3) (Factory 2), 11.3 mg/m(3) (Factory 3), 6.8 mg/m(3) (Factory 4), 4.7 mg/m(3) (Factory 5), and 3.0 mg/m(3) (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m(3)-0.477 mg/m(3), 0.001 mg/m(3)-0.080 mg/m(3) and 0.001 mg/m(3)-0.058 mg/m(3) respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems.

  17. Selective concentration of aromatic bases from water with a resin adsorbent

    USGS Publications Warehouse

    Stuber, H.A.; Leenheer, J.A.

    1983-01-01

    Aromatic bases are concentrated from water on columns of a resin adsorbent and recovered by aqueous-acid elution. The degree of concentration attainable depends on the ratio of the capacity factor (k) of the neutral form of the amine to that of the ionized form. Capacity factors of ionic forms of amines on XAD-8 resin (a methylacrylic ester polymer) are greater than zero, ranging from 20 to 250 times lower than those of their neutral forms; they increase with increasing hydrophobicity of the amine. Thus, desorption by acid is an edition (k during desorption >0) rather than a displacement (k during desorption = 0) process. The degree of concentration attainable on XAD-8 resin varies with the hydrophobicity of the amine, being limited for hydrophilic solutes (for example, pyridine) by small neutral-form k's, reaching a maximum for amines of intermediate hydrophobicity (for example, quinoline), and decreasing for more hydrophobc solutes (for example, acridine) because of their large ionic-form k's.

  18. Dry deposition of ammonia at environmental concentrations on selected plant species

    SciTech Connect

    Aneja, V.P.; Rogers, H.H.; Stahel, E.P.

    1986-12-01

    The deposition velocity of NH/sub 3/ on six plant species at environmental concentrations has been studied in a dynamic plant gas exchange reactor. The total resistance to the transport of NH/sub 3/ was studied. The aerodynamic resistance was determined directly by NH/sub 3/ gas absorption in aqueous solutions at environmental concentrations in a two-phase gradientless reactor modeling the transfer processes through the stomata in a leaf. The concentration of NH/sub 3/ in the gas phase ranged from 50 to 1000 ppb and the temperature varied from 25 to 30/sup 0/C. The results for the deposition velocity for NH/sub 3/, during the day, varied from 0.3 to 1.3 cm/s. The deposition velocities at night were about one order of magnitude smaller. These results are compared with estimates from the Froessling equation which consistently yields higher values of the same order of magnitude. To determine accurate atmospheric transport models or global budget models, a variable deposition velocity should be used to account for the diurnal and seasonal variations in the surface resistance.

  19. Effects of graphene oxide concentration on optical properties of ZnO/RGO nanocomposites and their application to photocurrent generation

    SciTech Connect

    Azarang, Majid E-mail: azarang@phys.usb.ac.ir; Shuhaimi, Ahmad; Sookhakian, M.; Yousefi, Ramin E-mail: raminyousefi@iaumis.ac.ir

    2014-08-28

    The effects of different concentrations of graphene oxide (GO) on the structure and optical properties of ZnO nanoparticles (NPs) were investigated. The nanocomposites were synthesized via the sol-gel method in a gelatin medium. X-ray diffraction patterns (XRD) and Fourier transform infrared spectroscopy indicated that the GO sheets were reduced and changed to reduced GO (RGO) during the calcination of the nanocomposites at 400 °C. In addition, the XRD patterns of the NPs indicated a hexagonal (wurtzite) structure for all the products. Microscopic studies showed that the NPs were decorated and dispersed on the RGO sheets very well. However, these studies revealed that the RGO concentration had an effect on the crystal growth process for the ZnO NPs. Furthermore, these studies showed that the NPs could be grown with a single crystal quality in an optimum RGO concentration. According to the XRD results that were obtained from pure ZnO NPs, the calcinations temperature was decreased by the RGO. UV–vis and room temperature photoluminescence studies showed that the optical properties of the ZnO/RGO nanocomposite were affected by the RGO concentration. Finally, the obtained ZnO/RGO nanocomposite was used to generate a photocurrent. Observations showed that the photocurrent intensity of the nanocomposite was significantly increased by increasing the RGO, with an optimum RGO concentration.

  20. X-ray fluorescence study of the concentration of selected trace and minor elements in human brain tumours

    NASA Astrophysics Data System (ADS)

    Wandzilak, Aleksandra; Czyzycki, Mateusz; Radwanska, Edyta; Adamek, Dariusz; Geraki, Kalotina; Lankosz, Marek

    2015-12-01

    Neoplastic and healthy brain tissues were analysed to discern the changes in the spatial distribution and overall concentration of elements using micro X-ray fluorescence spectroscopy. High-resolution distribution maps of minor and trace elements such as P, S, Cl, K, Ca, Fe, Cu and Zn made it possible to distinguish between homogeneous cancerous tissue and areas where some structures could be identified, such as blood vessels and calcifications. Concentrations of the elements in the selected homogeneous areas of brain tissue were compared between tumours with various malignancy grades and with the controls. The study showed a decrease in the average concentration of Fe, P, S and Ca in tissues with high grades of malignancy as compared to the control group, whereas the concentration of Zn in these tissues was increased. The changes in the concentration were found to be correlated with the tumour malignancy grade. The efficacy of micro X-ray fluorescence spectroscopy to distinguish between various types of cancer based on the concentrations of studied elements was confirmed by multivariate discriminant analysis. Our analysis showed that the most important elements for tissue classification are Cu, K, Fe, Ca, and Zn. This method made it possible to correctly classify histopathological types in 99.93% of the cases used to build the model and in as much as 99.16% of new cases.

  1. Periodic, quasiperiodic, and chaotic potentials generated by electrochemical concentration cells: Local and global dynamics

    NASA Astrophysics Data System (ADS)

    Zeyer, K.-P.; Münster, A. F.; Hauser, M. J. B.; Schneider, F. W.

    1994-09-01

    We extend previous work describing the passive electrical coupling of two periodic chemical states to include quasiperiodic and chaotic states. Our setup resembles an electrochemical concentration cell (a battery) whose half cells [continuous-flow stirred tank reactors (CSTRs)] each contain the Belousov-Zhabotinsky (BZ) reaction. For a closed electrical circuit the two half cells are weakly coupled by an external variable resistance and by a constant low mass flow. This battery may produce either periodic, quasiperiodic, or chaotic alternating current depending on the dynamic BZ states chosen in the half cells. A lower fractal dimensionality is calculated from the electrical potential of a single chaotic CSTR than from the difference potential (relative potential) of the two chaotic half cell potentials. A similar situation is observed in model calculations of a chaotic spatiotemporal system (the driven Brusselator in one space dimension) where the dimensionality derived from a local time series is lower than the dimensionality of the global trajectory calculated from the Karhunen-Loeve coefficients.

  2. In vivo selective cancer-tracking gadolinium eradicator as new-generation photodynamic therapy agent

    PubMed Central

    Zhang, Tao; Lan, Rongfeng; Chan, Chi-Fai; Law, Ga-Lai; Wong, Wai-Kwok; Wong, Ka-Leung

    2014-01-01

    In this work, we demonstrate a modality of photodynamic therapy (PDT) through the design of our truly dual-functional—PDT and imaging—gadolinium complex (Gd-N), which can target cancer cells specifically. In the light of our design, the PDT drug can specifically localize on the anionic cell membrane of cancer cells in which its laser-excited photoemission signal can be monitored without triggering the phototoxic generation of reactive oxygen species—singlet oxygen—before due excitation. Comprehensive in vitro and in vivo studies had been conducted for the substantiation of the effectiveness of Gd-N as such a tumor-selective PDT photosensitizer. This treatment modality does initiate a new direction in the development of “precision medicine” in line with stem cell and gene therapies as tools in cancer therapy. PMID:25453097

  3. Efficient and selective hydrogen generation from bioethanol using ruthenium pincer-type complexes.

    PubMed

    Sponholz, Peter; Mellmann, Dörthe; Cordes, Christoph; Alsabeh, Pamela G; Li, Bin; Li, Yang; Nielsen, Martin; Junge, Henrik; Dixneuf, Pierre; Beller, Matthias

    2014-09-01

    Catalytic generation of hydrogen from aqueous ethanol solution proceeds in the presence of pincer-type transition metal catalysts. Optimal results are obtained applying a [Ru(H)(Cl)(CO)(iPr2PEtN(H)EtPiPr2)] complex (catalyst TON 80,000) in the presence of water and base. This dehydrogenation reaction provides up to 70% acetic acid in a selective manner. For the first time, it is shown that bioethanol obtained from fermentation processes can be used directly in this protocol without the need for water removal. The produced hydrogen can be directly utilized in proton exchange membrane (PEM) fuel cells, since very low amounts of CO are formed.

  4. Efficient and selective hydrogen generation from bioethanol using ruthenium pincer-type complexes.

    PubMed

    Sponholz, Peter; Mellmann, Dörthe; Cordes, Christoph; Alsabeh, Pamela G; Li, Bin; Li, Yang; Nielsen, Martin; Junge, Henrik; Dixneuf, Pierre; Beller, Matthias

    2014-09-01

    Catalytic generation of hydrogen from aqueous ethanol solution proceeds in the presence of pincer-type transition metal catalysts. Optimal results are obtained applying a [Ru(H)(Cl)(CO)(iPr2PEtN(H)EtPiPr2)] complex (catalyst TON 80,000) in the presence of water and base. This dehydrogenation reaction provides up to 70% acetic acid in a selective manner. For the first time, it is shown that bioethanol obtained from fermentation processes can be used directly in this protocol without the need for water removal. The produced hydrogen can be directly utilized in proton exchange membrane (PEM) fuel cells, since very low amounts of CO are formed. PMID:25088665

  5. Efficient Generation and Selection of Virtual Populations in Quantitative Systems Pharmacology Models

    PubMed Central

    Rieger, TR; Musante, CJ

    2016-01-01

    Quantitative systems pharmacology models mechanistically describe a biological system and the effect of drug treatment on system behavior. Because these models rarely are identifiable from the available data, the uncertainty in physiological parameters may be sampled to create alternative parameterizations of the model, sometimes termed “virtual patients.” In order to reproduce the statistics of a clinical population, virtual patients are often weighted to form a virtual population that reflects the baseline characteristics of the clinical cohort. Here we introduce a novel technique to efficiently generate virtual patients and, from this ensemble, demonstrate how to select a virtual population that matches the observed data without the need for weighting. This approach improves confidence in model predictions by mitigating the risk that spurious virtual patients become overrepresented in virtual populations. PMID:27069777

  6. Effects of sampling, preparation and defecation on metal concentrations in selected invertebrates at urban sites.

    PubMed

    Zödl, Bettina; Wittmann, Karl J

    2003-08-01

    In order to obtain basic information for designing standardized test preparation methods, the heavy metals Zn, Cu, Cd and Pb were measured in gastropods (Xerolenta obvia), oligochaetes (Lumbricus terrestris), isopods (Armadillidium vulgare, Trachelipus rathkei) and carabids (Harpalus rubripes, Calathus fuscipes) using different sampling methods and different modes of sample treatment. In some of the experiments, higher Zn, Cd and Pb, and lower Cu-contents were observed in isopods and carabids trapped with formalin-pitfalls compared to manually collected specimens (which were allowed to defecate). Defecation had marked effects on the levels of all four metals investigated in oligochaetes, and on Cd and Pb in gastropods and isopods. Cellulose was fed as an accelerator of gut passage and showed a significant effect on the Pb concentration in the soft body of gastropods. Deionate-washed isopods (A. vulgare) showed higher Cd concentrations than ultrasonic-cleaned individuals. No marked differences were observed between heat-dried and freeze-dried isopods. Carabids showed strong sex-specific differences in metal concentrations. Based on these and previous results, invertebrates should be: collected in vivo, allowed to defecate, be freeze-fixed and (at least in arthropods) ultrasonic-cleaned, determined to species level and in certain groups (carabids) also to sex, and then be sized or sorted by size (age) before further preparation and analysis. If any of these treatments is impractical, comparable sampling and preparation methods are recommended as a minimum requirement in order to avoid bias in the results and/or interpretation. PMID:12820990

  7. Selective inhibition of crystal growth on octacalcium phosphate and nonstoichiometric hydroxyapatite by pyrophosphate at physiological concentration

    NASA Astrophysics Data System (ADS)

    Eidelman, N.; Brown, W. E.; Meyer, J. L.

    1991-09-01

    Octacalcium phosphate, Ca 8H 2(PO 4) 6·5H 2O (OCP), appears to be a precursor in biomineral formation. The formation of OCP as the precursor is supported by the observation that stoichiometric hydroxyapatite, Ca 5(PO 4) 3OH (OHAp), cannot form directly because of the presence of its growth inhibitors in serum. Therefore, the effects of the physiological concentration of pyrophosphate (P 2O 4-7), one of the most important calcium phosphate growth inhibitors in blood, on calcium phosphate growth rates on OCP and nonstoichiometric OHAp (apatite) seeds were measured. The amounts of seed crystals used to initiate the growth were adjusted by trial and error so that the control growth rates (in the absence of P 2O 4-7) were the same on both OCP and apatite seeds at a given supersaturation. The crystal growth on both kinds of seed crystals from supersaturated solutions in the presence of 1μM P 2O 4-7 added once ("one-time" addition) at constant pH (7.4) and 25°C was determined by KOH titration and decreases in Ca and PO 4 concentrations in the solutions. Crystal growth on OCP seed crystals in the presence of a constant concentration of 1μM P 2O 4-7 was also measured. The growing phases were characterized by ‡Ca/‡PO 4 ratios, chemical potential plots, X-ray diffraction (XRD) and Fourier transform infrared (FTIR). The results of this study show that: (1) P 2O 4-7 ions inhibited the growth on the apatite seeds more than on the OCP seeds; (2) apparently OCP precipitated on both types of seeds, followed by its hydrolysis to a more apatite-like phase; (3) slower crystal growth was observed on OCP seeds in the presence of a constant physiological concentration of P 2O 4-7 (1μM) than in the "one-time" addition of P 2O 4-7.

  8. Concentric transmon qubit featuring fast tunability and site-selective Z coupling

    NASA Astrophysics Data System (ADS)

    Weides, Martin; Braumueller, Jochen; Sandberg, Martin; Vissers, Michael; Schneider, Andre; Schloer, Steffen; Gruenhaupt, Lukas; Rotzinger, Hannes; Marthaler, Michael; Lukashenko, Alexander; Dieter, Amadeus; Ustinov, Alexey; Pappas, David

    We present a planar qubit design based on a superconducting circuit that we call concentric transmon. While employing a simple fabrication process using Al evaporation and lift-off lithography, we observe qubit lifetimes and coherence times in the order of 10 μs. We systematically characterize loss channels such as incoherent dielectric loss, Purcell decay and radiative losses. The implementation of a gradiometric SQUID loop allows for a fast tuning of the qubit transition frequency and therefore for full tomographic control of the quantum circuit. The presented qubit design features a passive direct Z coupling between neighboring qubits, being a pending quest in the field of quantum simulation.

  9. Isolated metal active site concentration and stability control catalytic CO2 reduction selectivity.

    PubMed

    Matsubu, John C; Yang, Vanessa N; Christopher, Phillip

    2015-03-01

    CO2 reduction by H2 on heterogeneous catalysts is an important class of reactions that has been studied for decades. However, atomic scale details of structure-function relationships are still poorly understood. Particularly, it has been suggested that metal particle size plays a unique role in controlling the stability of CO2 hydrogenation catalysts and the distribution of active sites, which dictates reactivity and selectivity. These studies often have not considered the possible role of isolated metal active sites in the observed dependences. Here, we utilize probe molecule diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with known site-specific extinction coefficients to quantify the fraction of Rh sites residing as atomically dispersed isolated sites (Rhiso), as well as Rh sites on the surface of Rh nanoparticles (RhNP) for a series of TiO2 supported Rh catalysts. Strong correlations were observed between the catalytic reverse water gas shift turn over frequency (TOF) and the fraction of Rhiso sites and between catalytic methanation TOF and the fraction of RhNP sites. Furthermore, it was observed that reaction condition-induced disintegration of Rh nanoparticles, forming Rhiso active sites, controls the changing reactivity with time on stream. This work demonstrates that isolated atoms and nanoparticles of the same metal on the same support can exhibit uniquely different catalytic selectivity in competing parallel reaction pathways and that disintegration of nanoparticles under reaction conditions can play a significant role in controlling stability.

  10. Isolated metal active site concentration and stability control catalytic CO2 reduction selectivity.

    PubMed

    Matsubu, John C; Yang, Vanessa N; Christopher, Phillip

    2015-03-01

    CO2 reduction by H2 on heterogeneous catalysts is an important class of reactions that has been studied for decades. However, atomic scale details of structure-function relationships are still poorly understood. Particularly, it has been suggested that metal particle size plays a unique role in controlling the stability of CO2 hydrogenation catalysts and the distribution of active sites, which dictates reactivity and selectivity. These studies often have not considered the possible role of isolated metal active sites in the observed dependences. Here, we utilize probe molecule diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with known site-specific extinction coefficients to quantify the fraction of Rh sites residing as atomically dispersed isolated sites (Rhiso), as well as Rh sites on the surface of Rh nanoparticles (RhNP) for a series of TiO2 supported Rh catalysts. Strong correlations were observed between the catalytic reverse water gas shift turn over frequency (TOF) and the fraction of Rhiso sites and between catalytic methanation TOF and the fraction of RhNP sites. Furthermore, it was observed that reaction condition-induced disintegration of Rh nanoparticles, forming Rhiso active sites, controls the changing reactivity with time on stream. This work demonstrates that isolated atoms and nanoparticles of the same metal on the same support can exhibit uniquely different catalytic selectivity in competing parallel reaction pathways and that disintegration of nanoparticles under reaction conditions can play a significant role in controlling stability. PMID:25671686

  11. Effect of Exposure to Hyperoxic, Hypobaric, and Hyperbaric Environments on Concentrations of Selected Aerobic and Anaerobic Fecal Flora of Mice

    PubMed Central

    Gillmore, James D.; Gordon, Francis B.

    1975-01-01

    Alterations in selected aerobic and anaerobic fecal microflora of the mouse were determined during exposure to hyperoxic and normoxic hypo- and hyperbaric environments. Examination of fecal cultures obtained during exposure for 6 weeks to either 60 or 77% oxygen concentration at 1 atmosphere absolute revealed little alteration in the aerobic or anaerobic flora. There appeared to be only a retardation in the reduction of the Klebsiella-Enterobacter flora which normally occurs after weaning. During exposure to hypobaric environments (100% O2, 0.2 atmosphere absolute), significant alterations in concentrations of Escherichia coli, slow lactose fermenters, Klebsiella-Enterobacter, and enterococci were found in some instances. All alterations were toward increased concentrations. Variations in concentrations of different colony types of obligately anaerobic gram-positive (anGPR) and gram-negative (anGNR) rods cultured during the same experiments also occurred. One colony type of anGPR appeared to decrease while a second type increased in numbers. Concentrations of three colony types of anGNR were generally, but not always, increased. During hyperbaric exposure (2.8% O2, 7.5 atmospheres absolute), increased concentrations of Klebsiella-Enterobacter, E. coli, slow lactose fermenters and enterococci were also noted. Changes in numbers of both colony types of anGPR, when occurring, were in the direction of lower numbers. Alteration in numbers of anGNR were in both directions but were more frequent in the direction of higher numbers. After return to normal air for 4 weeks of either hypo- or hyperbaric exposure, fecal concentrations of all organisms tended to revert toward control values with the exception of the anGPR which remained in lower concentrations after termination of the hyperbaric exposure. These observations indicate that, despite the great variation in the fecal flora among individual mice, it is possible to discover the effects induced by altered gaseous

  12. Correlation between some selected trace metal concentrations in six species of fish from the Arabian Sea

    SciTech Connect

    Ashraf, M.; Jaffar, M.

    1988-07-01

    The role of trace metals in marine ecosystems has been keenly investigated during recent years. It is known that abundance of essential trace metals regulates the metal content in the organisms by homeostatic control mechanisms, which when cease to function cause essential trace metals to act in an either acutely or chronically toxic manner. Therefore, a correlation study based on essential and non-essential trace metal concentrations is imperative for extending the existing knowledge of bioaccumulation of trace metals in marine organisms. An attempt has been made in the present investigation to bring out quantitative correlations between the concentrations of iron, copper, lead and zinc in the edible muscle tissue of six species of marine fish: Salmon (salmon sole); tuna (thunnus thynnus); pomfret silver (pampus argenteus); Pomfret black (formioniger); long tail tuna (thynnus tonggel) and Indian oil sardine (sardinella longiceps). These fish are abundantly available in Pakistan along the coastal line of the Arabian Sea and have great commercial value. The computational analysis on the trace metal correlation was conducted using an MSTAT statistical package.

  13. [Field experiment of F1 generation and superior families selection of Dendrobium officinale].

    PubMed

    Zhang, Xiao-Ling; Si, Jin-Ping; Wu, Ling-Shang; Guo, Ying-Ying; Yu, Jie; Wang, Lin-Hua

    2013-11-01

    Based on randomized block design of experiment, agronomic traits and yields of 14 F1 generations of Dendrobium officinale were determined. The results showed that the differences in agronomic traits and yields among families were significant, and the hybrid vigor was obvious. Families of 6b x 2a, 9 x 66 and 78 x 69 were selected with the remarkable superiority of yields, agronomic traits and product customization. Correlation analysis between agronomic traits and yields showed that plant height, stem diameter, leaf number, blade length and blade width were all significantly correlated with biological yields and economic yields. Among which, stem diameter, leaf number and blade length were the most significant, and an optimal linear regression model could be established. When the number of shoots was fewer than 4.5, both biological yields and economic yields increased with the increasing number of shoots, but it could not much affect yields when the number of shoots was larger than 4.5. Shoots number, stem diameter and leaf index were basic stability when compared biennial traits to annual, which could be used for early selection. PMID:24558865

  14. Generating entanglement via symmetry-selective bath engineering in superconducting qubits

    NASA Astrophysics Data System (ADS)

    Siddiqi, Irfan; Schwartz, Mollie; Martin, Leigh; Flurin, Emmanuel; Aron, Camille; Kulkarni, Manas; Tureci, Hakan

    Bath engineering, which utilizes coupling to lossy modes in a quantum system to generate non-trivial steady states, is a potential alternative to gate- and measurement-based quantum science. In this talk, we discuss autonomous stabilization of entanglement between two superconducting transmon qubits in a symmetry-selective manner. Our experiments are implemented using two 3D transmons housed in separate copper cavities. The cavities are coupled via an aperture, and hybridize into nondegenerate symmetric and antisymmetric bath modes. We utilize the engineered symmetries of the dissipative environment to stabilize a target Bell state 1/√{ 2} | ge > +/- | eg > in the qubit sector; we further demonstrate suppression of the Bell state of opposite symmetry due to parity selection rules. This implementation is resource-efficient, achieves a steady-state fidelity <- = 0 . 70 , and is scalable to multiple qubits. http://arxiv.org/abs/1511.00702 This research was supported by the ARO.

  15. Conducting ion tracks generated by charge-selected swift heavy ions

    NASA Astrophysics Data System (ADS)

    Gupta, Srashti; Gehrke, H. G.; Krauser, J.; Trautmann, C.; Severin, D.; Bender, M.; Rothard, H.; Hofsäss, H.

    2016-08-01

    Conducting ion tracks in tetrahedral amorphous carbon (ta-C) thin films were generated by irradiation with swift heavy ions of well-defined charge state. The conductivity of tracks and the surface topography of the films, showing characteristic hillocks at each track position, were investigated using conductive atomic force microscopy measurements. The dependence of track conductivity and hillock size on the charge state of the ions was studied using 4.6 MeV/u Pb ions of charge state 53+, 56+ and 60+ provided by GANIL, as well as 4.8 MeV/u Bi and Au ions of charge state from 50+ to 61+ and 4.2 MeV/u 238U ions in equilibrium charge state provided by UNILAC of GSI. For the charge state selection at GSI, an additional stripper-foil system was installed at the M-branch that now allows routine irradiations with ions of selected charge states. The conductivity of tracks in ta-C increases significantly when the charge state increases from 51+ to 60+. However, the conductivity of individual tracks on the same sample still shows large variations, indicating that tracks formed in ta-C are either inhomogeneous or the conductivity is limited by the interface between ion track and Si substrate.

  16. Making Their Way: An Interpretive Case Study of Male First-Generation Students Attending a Highly Selective Liberal Arts College

    ERIC Educational Resources Information Center

    Peltz, Mark R.

    2013-01-01

    This qualitative study focused on the experiences of eight male first-generation college students attending Kenmont College (pseudonym), a highly selective, residential liberal arts college located in the Midwestern United States. While first-generation college students have been studied in various contexts, very little is known about what…

  17. Second generation bioethanol potential from selected Malaysia's biodiversity biomasses: A review.

    PubMed

    Aditiya, H B; Chong, W T; Mahlia, T M I; Sebayang, A H; Berawi, M A; Nur, Hadi

    2016-01-01

    Rising global temperature, worsening air quality and drastic declining of fossil fuel reserve are the inevitable phenomena from the disorganized energy management. Bioethanol is believed to clear out the effects as being an energy-derivable product sourced from renewable organic sources. Second generation bioethanol interests many researches from its unique source of inedible biomass, and this paper presents the potential of several selected biomasses from Malaysia case. As one of countries with rich biodiversity, Malaysia holds enormous potential in second generation bioethanol production from its various agricultural and forestry biomasses, which are the source of lignocellulosic and starch compounds. This paper reviews potentials of biomasses and potential ethanol yield from oil palm, paddy (rice), pineapple, banana and durian, as the common agricultural waste in the country but uncommon to be served as bioethanol feedstock, by calculating the theoretical conversion of cellulose, hemicellulose and starch components of the biomasses into bioethanol. Moreover, the potential of the biomasses as feedstock are discussed based on several reported works.

  18. Selection of the reference steam generator for the advanced liquid metal reactor

    SciTech Connect

    Loewen, Eric P.; Boardman, Chuck

    2007-07-01

    In February 2006 President Bush announced the Advanced Energy Initiative, which included the Department of Energy's (DOE) Global Nuclear Energy Partnership (GNEP). GNEP has seven broad goals; one of the major elements being to develop and deploy advanced nuclear fuel recycling technology that includes consuming spent nuclear fuel in an Advanced Recycling Reactor (ARR). DOE is contemplating accelerating the deployment of these technologies to achieve the construction of a commercial scale application of these technologies. DOE now defines this approach as 'two simultaneous tracks: (1) deployment of commercial scale facilities for which advanced technologies are available now or in the near future, and (2) further research and development of transmutation fuels technologies'. GEHitachi Nuclear Energy Americas LLC (GHNEA) believes an integrated technical solution is achievable in the near term to accelerate the commercial demonstration of GNEP infrastructure. The GHNEA ARR concept involves a single integrated recycling facility sized to service a single reactor module ARR capable of destroying light water and fast reactor sourced actinides. This paper describes the bases and rationale behind the selection of the helical coil steam generator (HCSG) as the reference steam generator concept for the ALMR and S-PRISM reactor concepts. (authors)

  19. Second generation bioethanol potential from selected Malaysia's biodiversity biomasses: A review.

    PubMed

    Aditiya, H B; Chong, W T; Mahlia, T M I; Sebayang, A H; Berawi, M A; Nur, Hadi

    2016-01-01

    Rising global temperature, worsening air quality and drastic declining of fossil fuel reserve are the inevitable phenomena from the disorganized energy management. Bioethanol is believed to clear out the effects as being an energy-derivable product sourced from renewable organic sources. Second generation bioethanol interests many researches from its unique source of inedible biomass, and this paper presents the potential of several selected biomasses from Malaysia case. As one of countries with rich biodiversity, Malaysia holds enormous potential in second generation bioethanol production from its various agricultural and forestry biomasses, which are the source of lignocellulosic and starch compounds. This paper reviews potentials of biomasses and potential ethanol yield from oil palm, paddy (rice), pineapple, banana and durian, as the common agricultural waste in the country but uncommon to be served as bioethanol feedstock, by calculating the theoretical conversion of cellulose, hemicellulose and starch components of the biomasses into bioethanol. Moreover, the potential of the biomasses as feedstock are discussed based on several reported works. PMID:26253329

  20. Large-Scale Selection and Breeding To Generate Industrial Yeasts with Superior Aroma Production

    PubMed Central

    Steensels, Jan; Meersman, Esther; Snoek, Tim; Saels, Veerle

    2014-01-01

    The concentrations and relative ratios of various aroma compounds produced by fermenting yeast cells are essential for the sensory quality of many fermented foods, including beer, bread, wine, and sake. Since the production of these aroma-active compounds varies highly among different yeast strains, careful selection of variants with optimal aromatic profiles is of crucial importance for a high-quality end product. This study evaluates the production of different aroma-active compounds in 301 different Saccharomyces cerevisiae, Saccharomyces paradoxus, and Saccharomyces pastorianus yeast strains. Our results show that the production of key aroma compounds like isoamyl acetate and ethyl acetate varies by an order of magnitude between natural yeasts, with the concentrations of some compounds showing significant positive correlation, whereas others vary independently. Targeted hybridization of some of the best aroma-producing strains yielded 46 intraspecific hybrids, of which some show a distinct heterosis (hybrid vigor) effect and produce up to 45% more isoamyl acetate than the best parental strains while retaining their overall fermentation performance. Together, our results demonstrate the potential of large-scale outbreeding to obtain superior industrial yeasts that are directly applicable for commercial use. PMID:25192996

  1. Large-scale selection and breeding to generate industrial yeasts with superior aroma production.

    PubMed

    Steensels, Jan; Meersman, Esther; Snoek, Tim; Saels, Veerle; Verstrepen, Kevin J

    2014-11-01

    The concentrations and relative ratios of various aroma compounds produced by fermenting yeast cells are essential for the sensory quality of many fermented foods, including beer, bread, wine, and sake. Since the production of these aroma-active compounds varies highly among different yeast strains, careful selection of variants with optimal aromatic profiles is of crucial importance for a high-quality end product. This study evaluates the production of different aroma-active compounds in 301 different Saccharomyces cerevisiae, Saccharomyces paradoxus, and Saccharomyces pastorianus yeast strains. Our results show that the production of key aroma compounds like isoamyl acetate and ethyl acetate varies by an order of magnitude between natural yeasts, with the concentrations of some compounds showing significant positive correlation, whereas others vary independently. Targeted hybridization of some of the best aroma-producing strains yielded 46 intraspecific hybrids, of which some show a distinct heterosis (hybrid vigor) effect and produce up to 45% more isoamyl acetate than the best parental strains while retaining their overall fermentation performance. Together, our results demonstrate the potential of large-scale outbreeding to obtain superior industrial yeasts that are directly applicable for commercial use. PMID:25192996

  2. Chemical function based pharmacophore generation of endothelin-A selective receptor antagonists.

    PubMed

    Funk, Oliver F; Kettmann, Viktor; Drimal, Jan; Langer, Thierry

    2004-05-20

    Both quantitative and qualitative chemical function based pharmacophore models of endothelin-A (ET(A)) selective receptor antagonists were generated by using the two algorithms HypoGen and HipHop, respectively, which are implemented in the Catalyst molecular modeling software. The input for HypoGen is a training set of 18 ET(A) antagonists exhibiting IC(50) values ranging between 0.19 nM and 67 microM. The best output hypothesis consists of five features: two hydrophobic (HY), one ring aromatic (RA), one hydrogen bond acceptor (HBA), and one negative ionizable (NI) function. The highest scoring Hip Hop model consists of six features: three hydrophobic (HY), one ring aromatic (RA), one hydrogen bond acceptor (HBA), and one negative ionizable (NI). It is the result of an input of three highly active, selective, and structurally diverse ET(A) antagonists. The predictive power of the quantitative model could be approved by using a test set of 30 compounds, whose activity values spread over 6 orders of magnitude. The two pharmacophores were tested according to their ability to extract known endothelin antagonists from the 3D molecular structure database of Derwent's World Drug Index. Thereby the main part of selective ET(A) antagonistic entries was detected by the two hypotheses. Furthermore, the pharmacophores were used to screen the Maybridge database. Six compounds were chosen from the output hit lists for in vitro testing of their ability to displace endothelin-1 from its receptor. Two of these are new potential lead compounds because they are structurally novel and exhibit satisfactory activity in the binding assay. PMID:15139753

  3. Chemical function based pharmacophore generation of endothelin-A selective receptor antagonists.

    PubMed

    Funk, Oliver F; Kettmann, Viktor; Drimal, Jan; Langer, Thierry

    2004-05-20

    Both quantitative and qualitative chemical function based pharmacophore models of endothelin-A (ET(A)) selective receptor antagonists were generated by using the two algorithms HypoGen and HipHop, respectively, which are implemented in the Catalyst molecular modeling software. The input for HypoGen is a training set of 18 ET(A) antagonists exhibiting IC(50) values ranging between 0.19 nM and 67 microM. The best output hypothesis consists of five features: two hydrophobic (HY), one ring aromatic (RA), one hydrogen bond acceptor (HBA), and one negative ionizable (NI) function. The highest scoring Hip Hop model consists of six features: three hydrophobic (HY), one ring aromatic (RA), one hydrogen bond acceptor (HBA), and one negative ionizable (NI). It is the result of an input of three highly active, selective, and structurally diverse ET(A) antagonists. The predictive power of the quantitative model could be approved by using a test set of 30 compounds, whose activity values spread over 6 orders of magnitude. The two pharmacophores were tested according to their ability to extract known endothelin antagonists from the 3D molecular structure database of Derwent's World Drug Index. Thereby the main part of selective ET(A) antagonistic entries was detected by the two hypotheses. Furthermore, the pharmacophores were used to screen the Maybridge database. Six compounds were chosen from the output hit lists for in vitro testing of their ability to displace endothelin-1 from its receptor. Two of these are new potential lead compounds because they are structurally novel and exhibit satisfactory activity in the binding assay.

  4. Characteristics of bacteria selected as inocula for the biodegradation of low concentrations of an organic compound

    SciTech Connect

    Pahm, M.A.

    1992-01-01

    A study was conducted to determine some physiological characteristics of bacteria that differ in their abilities to degrade low concentrations of p-nitrophenol (PNP) and to relate the differences in activity among species in pure culture to their behavior in environmental samples. The growth rates, threshold for growth and mineralization of PNP, response to phosphorus and other organic substrates, including dissolved organic carbon, and metabolic products of four bacteria capable of degrading PNP were determined. Pseudomanas sp. SP3 and Pseudomonas sp. K had similar growth rates at low concentrations of PNP but differed in their abilities to transform the chemical in culture. No significant increase in the growth rate of Pseudomonas sp. SP3 in solutions with 1, 10 and 100 ng of PNP per ml was observed, suggesting that its growth was at the expense of contaminating carbon. However, the strain formed organic products at 1 ng of PNP per ml, and it degraded 10 and 100 ng of PNP per ml appreciably. Flavobacterium sp. M1 had the highest growth rate among the four strains, but its growth and mineralization were inhibited by high PNP concentrations. In samples of an oligotrophic lake water inoculated with Pseudomonas sp. K, Flavobacterium sp. M1 and Pseudomonas sp. SP3, the rate of disappearance of 1 ng of PNP per ml correlated with the growth rates of the organisms in culture, but only during the first phase of the biphasic curve. Pseudomonas sp. K exhibited a threshold in culture but not in samples of lake and well water. Thus, growth characteristics in culture did not adequately prewater. Thus, growth characteristics in culture did not adequately predict the mineralization rates of low levels of PNP in samples of natural environments that were inoculated. Flavobacterium sp. M4, which had a threshold for growth at 2 ng of PNP per ml, degraded PNP in culture and in samples of an oligotrophic lake water at a higher rate and to a greater extent than Pseudomonas sp. K.

  5. Turbulent Size Selection and Concentration of Chondrule-Sized Objects: Reynolds Number Invariance and Implications

    NASA Technical Reports Server (NTRS)

    Cuzzi, J. N.; Hogan, R.; Dobrovolskis, A.; Paque, J.

    2006-01-01

    It is generally agreed that individual chondrules formed as entities in a gaseous nebula prior to being accumulated into a meteorite parent body, within which they incur various forms of modification before arriving in our labs. While there are major unanswered questions about the properties of the nebula environment in which chondrules formed, the process by which the most primitive meteorites are formed overwhelmingly from chondrules must then be an aspect of "nebula processing". Textures in certain fragments of primitive meteorites might be summarized as being primarily chondrules and clastic, chondrule-sized, fragments of other minerals, each covered with a rim of fine dust with physical and chemical properties which are essentially independent of the composition and mineralogy of the underlying chondrule. This (unfortunately rather rare) texture was called "primary accretionary texture" to reflect their belief that it precedes subsequent stages in which fragmentation, comminution, mixing, heating, and other forms of alteration occur on the parent body(-ies). The size distribution of these chondrules and fragments, and the properties of their dusty rims, are key clues regarding the primary nebula accretion process. Even in the much more abundant meteorites which have clearly suffered internal mixing, abrasion, grinding, and even mineralogical alteration or replacement (due presumably to the collisional growth and heating process itself), key chondrule properties such as mean size and density remain relatively well defined, and well defined rims persist in many cases. It has been our goal to infer the key nebula processes indirectly from the properties of these very earliest primitive meteorites by making use of a theoretical framework in which the nebula possesses a plausible level of isotropic turbulence. We have shown that turbulence has the property of concentrating one particular particle size by orders of magnitude, where the preferentially concentrated

  6. Preliminary materials selection issues for the next generation nuclear plant reactor pressure vessel.

    SciTech Connect

    Natesan, K.; Majumdar, S.; Shankar, P. S.; Shah, V. N.; Nuclear Engineering Division

    2007-03-21

    In the coming decades, the United States and the entire world will need energy supplies to meet the growing demands due to population increase and increase in consumption due to global industrialization. One of the reactor system concepts, the Very High Temperature Reactor (VHTR), with helium as the coolant, has been identified as uniquely suited for producing hydrogen without consumption of fossil fuels or the emission of greenhouse gases [Generation IV 2002]. The U.S. Department of Energy (DOE) has selected this system for the Next Generation Nuclear Plant (NGNP) Project, to demonstrate emissions-free nuclear-assisted electricity and hydrogen production within the next 15 years. The NGNP reference concepts are helium-cooled, graphite-moderated, thermal neutron spectrum reactors with a design goal outlet helium temperature of {approx}1000 C [MacDonald et al. 2004]. The reactor core could be either a prismatic graphite block type core or a pebble bed core. The use of molten salt coolant, especially for the transfer of heat to hydrogen production, is also being considered. The NGNP is expected to produce both electricity and hydrogen. The process heat for hydrogen production will be transferred to the hydrogen plant through an intermediate heat exchanger (IHX). The basic technology for the NGNP has been established in the former high temperature gas reactor (HTGR) and demonstration plants (DRAGON, Peach Bottom, AVR, Fort St. Vrain, and THTR). In addition, the technologies for the NGNP are being advanced in the Gas Turbine-Modular Helium Reactor (GT-MHR) project, and the South African state utility ESKOM-sponsored project to develop the Pebble Bed Modular Reactor (PBMR). Furthermore, the Japanese HTTR and Chinese HTR-10 test reactors are demonstrating the feasibility of some of the planned components and materials. The proposed high operating temperatures in the VHTR place significant constraints on the choice of material selected for the reactor pressure vessel for

  7. Concentrations of selected chlorinated pesticides in shrimp collected from the Calcasieu River/Lake Complex, Louisiana

    SciTech Connect

    Murray, H.E.; Beck, J.N. )

    1990-05-01

    For several decades inland and coastal aquatic ecosystems have been affected by a multitude of synthetic chemical substances. This is a consequence of population growth and increased industrial and agricultural activity. Many of these chemicals, the by-products of their production, and degradation products ultimately find their way into the aquatic environment as pollutants. The extent to which these pollutants affect the environment and its inhabitants depends largely upon the quantity and nature of the particular compounds involved. Halogenated hydrocarbons, particularly polychlorinated biphenyls (PCBs), and the pesticide DDT and its degradation products have received much attention as environmental pollutants. Because of the economic importance of the shrimping industry to southwest Louisiana, the objective of this study was to analyze shrimp collected from the Calcasieu River/Lake Complex for the presence of selected chlorinated pesticides. The presence of these compounds within shrimp tissues would serve as an indicator for the extent of pollution throughout this important estuarine system.

  8. Effects of maternal care and selection for low mortality on tyrosine hydroxylase concentrations and cell soma size in hippocampus and nidopallium caudolaterale in adult laying hen.

    PubMed

    Nordquist, R E; Zeinstra, E C; Rodenburg, T B; van der Staay, F J

    2013-01-01

    Feather pecking and cannibalism in farm-kept laying hens are damaging behaviors both in terms of animal welfare and economic loss, and a major challenge in modern poultry farming. Both rearing with a foster hen and genetic selection have been demonstrated to reduce feather pecking in laying hens. We examined the effects of rearing with a foster hen, genetic selection for low mortality from cannibalism, and interactions between both, using cellular morphology and levels of the rate-limiting enzyme in dopamine production, tyrosine hydroxylase, in the hippocampus and nidopallium caudolaterale (NCL) as a potential measure for laying hen welfare. Hens from the second generation of a sib-selection scheme line derived from a pure-bred White Leghorn line, selected for low mortality and for production characteristics, or their control line (CL) selected only for production characteristics, were housed with or without a foster Silky hen for the first 7 wk of life. Aside from the presence or absence of a foster Silky hen during the first 7 wk of life, housing conditions were identical for all hens. The hens were then sacrificed and brains were removed at 52 wk of age. Brains were sectioned and stained using a Nissl staining to reveal cell soma morphology, or using immunocytochemistry for tyrosine hydroxlase. A greater degree of lateralization in the hippocampus was observed in hens reared without a foster hen, as measured by absolute difference in cell soma size between hemispheres (P<0.05). The low mortality line showed decreased concentrations of tyrosine hydroxylase in the NCL compared with the CL (P<0.005). Our results indicate that morphological changes in brain induced in very early life can be detected in adult hens, and that genetic selection against mortality due to cannibalism impacts tyrosine hydroxylase in the NCL of laying hens. These observations strengthen the notion that brain measures may be useful as potential readouts for animal welfare. PMID:23048145

  9. Serum Concentrations of Selected Heavy Metals in Patients with Alcoholic Liver Cirrhosis from the Lublin Region in Eastern Poland

    PubMed Central

    Prystupa, Andrzej; Błażewicz, Anna; Kiciński, Paweł; Sak, Jarosław J.; Niedziałek, Jarosław; Załuska, Wojciech

    2016-01-01

    According to the WHO report, alcohol is the third most significant health risk factor for the global population. There are contrary reports about heavy metals concentrations in patients with alcoholic liver cirrhosis. The aim of this study was to investigate serum concentrations of selected heavy metals in patients with alcoholic liver cirrhosis living in the eastern part of Poland according to cirrhosis stage. The participants came from various hospitals of the Lublin region were enrolled. The study group included 46 male and 16 female patients. The control group consisted of 18 healthy individuals without liver disease. High Performance Ion Chromatography was used to determine the concentrations of metal ions (Cd, Zn, Cu, Ni, Co, Mn, and Pb) in serum samples. The concentrations of copper, zinc, nickel, and cobalt were found to be significantly lower in patients with alcoholic liver cirrhosis compared to the control group. The serum concentration of cadmium was significantly higher in patients with advanced alcoholic liver cirrhosis compared to the control group. We hypothesize that disorders of metabolism of heavy metals seem to be the outcome of impaired digestion and absorption, which are common in cirrhosis, improper diet, environmental and occupational exposure. PMID:27304961

  10. A source generation model for near-field seismic impact of coal fractures in stress concentration zones

    NASA Astrophysics Data System (ADS)

    Feng, Junjun; Wang, Enyuan; Shen, Rongxi; Chen, Liang; Li, Xuelong; Li, Nan

    2016-08-01

    To study the near-field seismic impact of coal fractures in stress concentration zones, we established a source generation model based on finite dislocation source theory and dynamic fracture mechanics, derived an analytical expression for near-field seismic displacements caused by coal fractures in the zone and numerically computed the resultant near-field seismic displacements within the coal mass. The results show that (1) the larger difference between the vertical and horizontal normal stresses in the stress concentration zone leads to a greater fracture speed, which thereby causes a stronger seismic impact; (2) the P-wave component in the near-field seismic displacements mainly impacts on the middle of the roadway, while the SH- and SV wave components mainly affect the junctions between the roadway and both the roof and the floor, and the damage caused by the SH- and SV waves within the coal mass is more significant than that caused by the P-waves; and (3) the effective way to mitigate the seismic impact induced by coal fractures in stress concentration zones is to reduce the difference between the vertical and horizontal normal stresses as far as possible. It is hoped that this study will provide a better understanding of the seismic impacts induced by coal fractures in stress concentration zones and thus help engineers to discover ways to prevent roadway failure.

  11. Impact of experimental haemodilution on platelet function, thrombin generation and clot firmness: effects of different coagulation factor concentrates

    PubMed Central

    Caballo, Carolina; Escolar, Gines; Diaz-Ricart, Maribel; Lopez-Vílchez, Irene; Lozano, Miguel; Cid, Joan; Pino, Marcos; Beltrán, Joan; Basora, Misericordia; Pereira, Arturo; Galan, Ana M.

    2013-01-01

    Background Haemodilution during resuscitation after massive haemorrhage may worsen the coagulopathy and perpetuate bleeding. Materials and methods Blood samples from healthy donors were diluted (30 and-60%) using crystalloids (saline, Ringer’s lactate, PlasmalyteTM) or colloids (6% hydroxyethylstarch [HES130/0.4], 5% human albumin, and gelatin). The effects of haemodilution on platelet adhesion (Impact R), thrombin generation (TG), and thromboelastometry (TEM) parameters were analysed as were the effects of fibrinogen, prothrombin complex concentrates (PCC), activated recombinant factor VII (FVIIa), and cryoprecipates on haemodilution. Results Platelet interactions was already significantly reduced at 30% haemodilution. Platelet reactivity was not improved by addition of any of the concentrates tested. A decrease in TG and marked alterations of TEM parameters were noted at 60% haemodilution. HES130/0.4 was the expander with the most deleterious action. TG was significantly enhanced by PCC whereas rFVIIa only caused a mild acceleration of TG initiation. Fibrinogen restored the alterations of TEM parameters caused by haemodilution including those caused by HES 130/0.4. Cryoprecipitates significantly improved the alterations caused by haemodilution on TG and TEM parameters; the effects on TG disappeared after ultracentrifugation of the cryoprecipitates. Discussion The haemostatic alterations caused by haemodilution are multifactorial and affect both blood cells and coagulation. In our in vitro approach, HES 130/0.4 had the most deleterious effect on haemostasis parameters. Coagulation factor concentrates did not improve platelet interactions in the Impact R, but did have favourable effects on coagulation parameters measured by TG and TEM. Fibrinogen notably improved TEM parameters without increasing thrombin generation, suggesting that this concentrate may help to preserve blood clotting abilities during haemodilution without enhancing the prothrombotic risk. PMID

  12. Effect of salt concentration and mediators in salt bridge microbial fuel cell for electricity generation from synthetic wastewater.

    PubMed

    Sevda, Surajbhan; Sreekrishnan, T R

    2012-01-01

    The aim of this study was to investigate the feasibility of using agar salt bridges for proton transport in Microbial Fuel Cells (MFC). It also tries to elucidate and effect of mediators on electricity production from wastewaters through experimentation using a simulated wastewater. In order to offset the very high cost of proton exchange membrane, salt bridges have been used in dual chamber MFCs. When the concentration of salt was varied in agar salt bridges from 1% to 10%, the volumetric power density changed from 1.71 to 84.99 mW/m(3) with a concomitant variation in power density from 0.32 to 16.02 mW/m(2). The maximum power density was observed at 5% salt concentration with 10% agar, which was accompanied by 88.41% COD reduction. In the case of methylene blue (0.01 mM) as the electron mediator, the voltage and current generation were 0.551 V and 0.47 mA, respectively. A maximum open circuit voltage of 0.718 V was seen at 0.08 mM methylene blue concentration, whereas maximum power densities of 17.59 mW/m(2) and 89.22 mW/m(3) were obtained. Different concentrations of neutral red were also tried out as mediators. A maximum open circuit voltage of 0.730 V was seen at 0.01 mM neutral red, corresponding to a power density of 12.02 mW/m(2) (volumetric power density of 60.97 mW/m(3)). Biofilm formation on the electrode surface was not observed in the presence of mediators, but was present in the absence of mediators. The results clearly demonstrated the feasibility to use agar salt bridge for proton transport and role of mediators in MFCs to generate electricity.

  13. Effect of salt concentration and mediators in salt bridge microbial fuel cell for electricity generation from synthetic wastewater.

    PubMed

    Sevda, Surajbhan; Sreekrishnan, T R

    2012-01-01

    The aim of this study was to investigate the feasibility of using agar salt bridges for proton transport in Microbial Fuel Cells (MFC). It also tries to elucidate and effect of mediators on electricity production from wastewaters through experimentation using a simulated wastewater. In order to offset the very high cost of proton exchange membrane, salt bridges have been used in dual chamber MFCs. When the concentration of salt was varied in agar salt bridges from 1% to 10%, the volumetric power density changed from 1.71 to 84.99 mW/m(3) with a concomitant variation in power density from 0.32 to 16.02 mW/m(2). The maximum power density was observed at 5% salt concentration with 10% agar, which was accompanied by 88.41% COD reduction. In the case of methylene blue (0.01 mM) as the electron mediator, the voltage and current generation were 0.551 V and 0.47 mA, respectively. A maximum open circuit voltage of 0.718 V was seen at 0.08 mM methylene blue concentration, whereas maximum power densities of 17.59 mW/m(2) and 89.22 mW/m(3) were obtained. Different concentrations of neutral red were also tried out as mediators. A maximum open circuit voltage of 0.730 V was seen at 0.01 mM neutral red, corresponding to a power density of 12.02 mW/m(2) (volumetric power density of 60.97 mW/m(3)). Biofilm formation on the electrode surface was not observed in the presence of mediators, but was present in the absence of mediators. The results clearly demonstrated the feasibility to use agar salt bridge for proton transport and role of mediators in MFCs to generate electricity. PMID:22423995

  14. Striatal and thalamic GABA level concentrations play differential roles for the modulation of response selection processes by proprioceptive information.

    PubMed

    Dharmadhikari, Shalmali; Ma, Ruoyun; Yeh, Chien-Lin; Stock, Ann-Kathrin; Snyder, Sandy; Zauber, S Elizabeth; Dydak, Ulrike; Beste, Christian

    2015-10-15

    The selection of appropriate responses is a complex endeavor requiring the integration of many different sources of information in fronto-striatal-thalamic circuits. An often neglected but relevant piece of information is provided by proprioceptive inputs about the current position of our limbs. This study examines the importance of striatal and thalamic GABA levels in these processes using GABA-edited magnetic resonance spectroscopy (GABA-MRS) and a Simon task featuring proprioception-induced interference in healthy subjects. As a possible model of deficits in the processing of proprioceptive information, we also included Parkinson's disease (PD) patients in this study. The results show that proprioceptive information about unusual postures complicates response selection processes in controls, but not in PD patients. The well-known deficits of PD patients in processing proprioceptive information can turn into a benefit when altered proprioceptive information would normally complicate response selection processes. Striatal and thalamic GABA levels play dissociable roles in the modulation of response selection processes by proprioceptive information: Striatal GABA levels seem to be important for the general speed of responding, most likely because striatal GABA promotes response selection. In contrast, the modulation of response conflict by proprioceptive information is closely related to thalamic GABA concentrations with higher concentration being related to a smaller response conflict effect. The most likely explanation for this finding is that the thalamus is involved in the integration of sensorimotor, attentional, and cognitive information for the purpose of response formation. Yet, this effect in the thalamus vanishes when controls and PD patients were analyzed separately.

  15. Striatal and thalamic GABA level concentrations play differential roles for the modulation of response selection processes by proprioceptive information.

    PubMed

    Dharmadhikari, Shalmali; Ma, Ruoyun; Yeh, Chien-Lin; Stock, Ann-Kathrin; Snyder, Sandy; Zauber, S Elizabeth; Dydak, Ulrike; Beste, Christian

    2015-10-15

    The selection of appropriate responses is a complex endeavor requiring the integration of many different sources of information in fronto-striatal-thalamic circuits. An often neglected but relevant piece of information is provided by proprioceptive inputs about the current position of our limbs. This study examines the importance of striatal and thalamic GABA levels in these processes using GABA-edited magnetic resonance spectroscopy (GABA-MRS) and a Simon task featuring proprioception-induced interference in healthy subjects. As a possible model of deficits in the processing of proprioceptive information, we also included Parkinson's disease (PD) patients in this study. The results show that proprioceptive information about unusual postures complicates response selection processes in controls, but not in PD patients. The well-known deficits of PD patients in processing proprioceptive information can turn into a benefit when altered proprioceptive information would normally complicate response selection processes. Striatal and thalamic GABA levels play dissociable roles in the modulation of response selection processes by proprioceptive information: Striatal GABA levels seem to be important for the general speed of responding, most likely because striatal GABA promotes response selection. In contrast, the modulation of response conflict by proprioceptive information is closely related to thalamic GABA concentrations with higher concentration being related to a smaller response conflict effect. The most likely explanation for this finding is that the thalamus is involved in the integration of sensorimotor, attentional, and cognitive information for the purpose of response formation. Yet, this effect in the thalamus vanishes when controls and PD patients were analyzed separately. PMID:26142275

  16. Sensitive and selective analysis of a wide concentration range of IGFBP7 using a surface plasmon resonance biosensor.

    PubMed

    Jang, Dae-Ho; Choi, Youngbo; Choi, Yong-Soo; Kim, Sun-Mi; Kwak, Hojung; Shin, Se-Hyun; Hong, Surin

    2014-11-01

    A sensitive method for selectively detecting insulin-like growth factor-binding protein 7 (IGFBP7) over a wide range of concentrations based on the surface plasmon resonance (SPR) biosensing techniques is described. IGFBP7 has been shown to regulate cell proliferation, cell adhesion, cellular senescence, apoptosis, and angiogenesis in several different cancer cell lines. Since the concentration of IGFBP7 can vary widely in the body, determining the precise concentration of IGFBP7 over a wide range of concentrations is important, since it serves as an inducible biomarker for both disease diagnosis and subsequent therapy. The SPR sensing method is based on the selective interaction of IGFBP7 with specific anti-IGFBP7 proteins on a gold thin film, which was covalently bound to the Fc-binding domain of protein G on a mixed self-assembled monolayer composed of DSNHS (S2(CH2)11COO(CH2)2COO-(N-hydroxysuccinimide)) and mercaptoundecanol, and effect of this on changes in the SPR profiles. The limit of detection (LOD) of the SPR biosensor was determined to be 10 ng/ml, which is a reasonable LOD value for biomedical applications. The response is essentially linear in the concentration range of 10-300 ng/ml. The SPR biosensor also shows specificity for IGFBP7 compared to that for biologically relevant interleukin (IL) derivatives including IL4, IL23, IL29, and IFG1. These molecules are also present along with IGFBP7 in the cell culture medium and have the potential to interfere with the analysis. Finally, the level secretion of IGFBP7 from cancer cells detected by the SPR biosensor showed a good correlation with a commercial kit using an IGFBP7 enzyme-linked immunosorbent assay. The findings reported herein indicate that the SPR biosensor for IGFBP7 would be applicable in a wide variety of biomedical fields.

  17. Chemistry and origin of minor and trace elements in selected vitrinite concentrates from bituminous and anthracitic coals

    USGS Publications Warehouse

    Palmer, C.A.; Lyons, P.C.

    1990-01-01

    Twelve hand-picked vitrinite concentrates and companion whole-coal samples were analyzed for trace and minor elements by instrumental neutron activation analysis (INAA) and direct-current-arc spectrographic techniques (DCAS). The vitrinite concentrates contained 94 to nearly 100 vol.% vitrinite compared to 71-95 vol.% in the companion whole coals. The ash contents of the vitrinite concentrates were 2 to more than 190 times less than the ash contents of the companion whole coals. Organic and inorganic affinities were determined by comparing the elemental concentrations in the vitrinite concentrates to the concentrations in the companion whole coals. The ratios of these concentrations for 33 selected elements are shown in Figure 1. Ratios greater than 1 indicate organic affinity, and ratios less than 1 indicate inorganic affinity. Br and W generally showed organic affinity in all samples in this study. In the nine samples from the eastern United States (Fig. 1A-C) less than one-fourth of the trace elements show organic affinity compared to nearly one-half for the three English and Australian samples (Fig. 1D). The elements that generally show organic affinity in the non-U.S.A. samples studied include As, Cs, Hf, and Ni, which have generally inorganic affinities in the U.S.A. samples, and Cr, Sb, Se, and U, which have mixed (both organic and inorganic) affinities, in the U.S.A. coals studied, has an inorganic affinity in the English coals studied. B shows organic affinity in the samples from the Illinois basin (Fig. 1C). For the samples studied, Ba shows organic affinity in the Appalachian basin bituminous coals (Fig. 1B), inorganic affinity in the Illinois basin coals, and overall mixed affinities. In all the samples studied, Cu, Mn, Na, Sr, Ta, V, and Zn show mixed affinities, and A1, Co, Eu, Fe, Ga, K, La, Mg, Sc, Si, Th, Ti, and Ub have generally inorganic affinity. ?? 1990.

  18. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats.

    PubMed

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats' hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations. PMID:27043135

  19. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats

    PubMed Central

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats’ hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations. PMID:27043135

  20. The Impact of Carrot Enriched in Iodine through Soil Fertilization on Iodine Concentration and Selected Biochemical Parameters in Wistar Rats.

    PubMed

    Piątkowska, Ewa; Kopeć, Aneta; Bieżanowska-Kopeć, Renata; Pysz, Mirosław; Kapusta-Duch, Joanna; Koronowicz, Aneta Agnieszka; Smoleń, Sylwester; Skoczylas, Łukasz; Ledwożyw-Smoleń, Iwona; Rakoczy, Roksana; Maślak, Edyta

    2016-01-01

    Iodine is one of the trace elements which are essential for mammalian life. The major objective of iodine biofortification of plants is to obtain food rich in this trace element, which may increase its consumption by various populations. Additionally, it may reduce the risk of iodine deficiency diseases. In this research for the first time we have assessed the bioavailability of iodine from raw or cooked carrot biofortified with this trace element on iodine concentration in selected tissues and various biochemical parameters as well as mRNA expression of some genes involved in iodine metabolism in Wistar rats. Statistically, a significantly higher iodine level was determined in urine, faeces and selected tissues of rats fed a diet containing biofortified raw carrot as compared to a diet without iodine and a diet containing control cooked carrot. Biofortified raw carrot significantly increased triiodothyronine concentration as compared to animals from other experimental groups. The highest thyroid stimulating hormone level was determined in rats fed control cooked carrots. mRNA expression of selected genes was affected by different dietary treatment in rats' hearts. Biofortified raw and cooked carrot could be taken into account as a potential source of iodine in daily diets to prevent iodine deficiency in various populations.

  1. Concentration Polarization and Nonequilibrium Electro-osmotic Instability at an Ion-Selective Surface Admitting Normal Flow

    NASA Astrophysics Data System (ADS)

    Khair, Aditya

    2011-11-01

    We revisit and build upon on the prototypical problem of ion transport across a flat ideal ion-selective surface. Specifically, we examine the influence of imposed fluid flows on concentration polarization (CP) and electrokinetic instability at over-limiting currents. We consider an ion-selective surface, or membrane, that admits a uniform flow across itself. The membrane contacts an electrolyte, whose concentration is uniform in a well-mixed region at a prescribed distance from the membrane. A voltage across the system drives an ionic current, leading to CP in the ``unstirred layer'' between the membrane and well-mixed bulk. The CP reflects a balance between advection of ions with the ``normal flow'' and diffusion. A Peclet number, Pe, parameterizes their relative importance; note, Pe is signed, as the flow can be toward or away from the membrane. An asymptotic analysis for thin Debye layers reveals a nonlinear CP profile, in contrast to the familiar linear profile at Pe=0. Next, we consider over-limiting currents, wherein a non-equilibrium space-charge layer emerges near the membrane surface. Finally, we examine the instability of the quiescent concentration polarization due to second-kind electro-osmosis in the space-charge layer. A stability analysis shows that the imposed normal flow can enhance or retard the instability, depending on its direction.

  2. Microcultures of lactic acid bacteria: characterization and selection of strains, optimization of nutrients and gallic acid concentration.

    PubMed

    Guzmán-López, Oswaldo; Loera, Octavio; Parada, José Luis; Castillo-Morales, Alberto; Martínez-Ramírez, Cándida; Augur, Christopher; Gaime-Perraud, Isabelle; Saucedo-Castañeda, Gerardo

    2009-01-01

    Eighteen lactic acid bacteria (LAB) strains, isolated from coffee pulp silages were characterized according to both growth and gallic acid (GA) consumption. Prussian blue method was adapted to 96-well microplates to quantify GA in LAB microcultures. Normalized data of growth and GA consumption were used to characterize strains into four phenotypes. A number of 5 LAB strains showed more than 60% of tolerance to GA at 2 g/l; whereas at 10 g/l GA growth inhibition was detected to a different extent depending on each strain, although GA consumption was observed in seven studied strains (>60%). Lactobacillus plantarum L-08 was selected for further studies based on its capacity to degrade GA at 10 g/l (97%). MRS broth and GA concentrations were varied to study the effect on growth of LAB. Cell density and growth rate were optimized by response surface methodology and kinetic analysis. Maximum growth was attained after 7.5 h of cultivation, with a dilution factor of 1-1/2 and a GA concentration between 0.625 and 2.5 g/l. Results indicated that the main factor affecting LAB growth was GA concentration. The main contribution of this study was to propose a novel adaptation of a methodology to characterize and select LAB strains with detoxifying potential of simple phenolics based on GA consumption and tolerance. In addition, the methodology presented in this study integrated the well-known RSM with an experimental design based on successive dilutions.

  3. Dopant type and/or concentration selective dry photochemical etching of semiconductor materials

    DOEpatents

    Ashby, C.R.H.; Dishman, J.L.

    1985-10-11

    Disclosed is a method of selectively photochemically dry etching a first semiconductor material of a given composition in the presence of a second semiconductor material which is of a composition different from said first material, said second material substantially not being etched during said method. The method comprises subjecting both materials to the same photon flux of an energy greater than their respective direct bandgaps and to the same gaseous chemical etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said conditions also being such that the resultant electronic structure of the first semiconductor material under said photon flux is sufficient for the first material to undergo substantial photochemical etching under said conditions and being such that the resultant electronic structure of the second semiconductor material under said photon flux is not sufficient for the second material to undergo substantial photochemical etching under said conditions. In a preferred mode, the materials are subjected to a bias voltage which suppresses etching in n- or p-type material but not in p- or n-type material, respectively; or suppresses etching in the more heavily doped of two n-type or two p-type materials.

  4. Dopant type and/or concentration selective dry photochemical etching of semiconductor materials

    DOEpatents

    Ashby, Carol I. H.; Dishman, James L.

    1987-01-01

    A method of selectively photochemically dry etching a first semiconductor material of a given composition in the presence of a second semiconductor material which is of a composition different from said first material, said second material substantially not being etched during said method, comprises subjecting both materials to the same photon flux of an energy greater than their respective direct bandgaps and to the same gaseous chemical etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said conditions also being such that the resultant electronic structure of the first semiconductor material under said photon flux is sufficient for the first material to undergo substantial photochemical etching under said conditions and being such that the resultant electronic structure of the second semiconductor material under said photon flux is not sufficient for the second material to undergo substantial photochemical etching under said conditions. In a preferred mode, the materials are subjected to a bias voltage which suppresses etching in n- or p- type material but not in p- or n-type material, respectively; or suppresses etching in the more heavily doped of two n-type or two p-type materials.

  5. Literature review of the concentration ratios of selected radionuclides in freshwater and marine fish

    SciTech Connect

    Poston, T.M.; Klopfer, D.C.

    1986-09-01

    Concentration ratios (CR's) used for modeling the uptake and food chain transport of radionuclides in fish have usually been conservative; that is, at the high end of reported values. This practice ensures that the dose to the consumer of contaminated fish will not be underestimated. In many models, however, conservative values have been used for all variables that have any uncertainty associated with them. As a result the dose to the consumer is overestimated. Realistic CR values need to be developed to establish model parameters that will accurately reflect tissue burdens in fish and resulting dose rates to consumers. This report reviews and summarizes published literature on the uptake and distribution of stable and radioactive isotopes of 26 elements. Based on this review, we have made recommendations on CR values to be used for modeling the accumulation of radionuclides in fish. Our recommendations are compared with CR values reported in other publications. A generic discussion of abiotic and biotic factors that influence CR values is provided so that CR values may be adjusted based on site-specific characteristics of the fishes habitat. Recommended CR values for freshwater fish and for marine fish are listed. Although this report emphasizes radionuclides, it is applicable to stable elements as well.

  6. Minimum inhibitory concentrations of selected antimicrobial agents for Moraxella bovoculi associated with infectious bovine keratoconjunctivitis.

    PubMed

    Angelos, John A; Ball, Louise M; Byrne, Barbara A

    2011-05-01

    Infectious bovine keratoconjunctivitis (IBK) has been associated with ocular infections by Moraxella bovis, the established etiologic agent of IBK, and more recently, Moraxella bovoculi, a recently described species of Moraxella. To assist in designing rational treatment regimens for M. bovoculi infections associated with IBK, the in vitro susceptibilities of 57 M. bovoculi field isolates cultured from eyes of cattle with IBK in California from 2002 through 2007 were determined. The minimum inhibitory concentration required to inhibit the growth of 90% of organisms (MIC(90)) of the following 18 antibiotics tested in the present study were: danofloxacin and enrofloxacin: ≤0.12 µg/ml; ampicillin and ceftiofur: ≤0.25 µg/ml; penicillin: 0.25 µg/ml; gentamicin: ≤1 µg/ml; chlortetracycline, oxytetracycline, and tiamulin: 1 µg/ml; florfenicol: 0.5 µg/ml; trimethoprim-sulfamethoxazole: ≤2/38 µg/ml; clindamycin: 2 µg/ml; neomycin and tilmicosin: ≤4 µg/ml; tulathromycin: 4 µg/ml; spectinomycin and tylosin: 16 µg/ml; and sulfadimethoxine: >256 µg/ml. The low MIC(90) of these M. bovoculi isolates suggests that commonly used antibiotics for treatment of IBK associated with M. bovis should also be effective against M. bovoculi. PMID:21908289

  7. Investigation of Antarctic sea ice concentration by means of selected algorithms. Final report, 1991-1992

    SciTech Connect

    Lomax, A.S.

    1992-05-08

    Changes in areal extent and concentration of sea ice around Antarctica may serve as sensitive indicators of global warming. A comparison study was conducted between the outputs of the three main algorithms currently in use (NASA Team, Comisco, and NORSEX) and a sea-ice model (Fine Resolution Antarctic Model). Data from the DMSP Special Sensor Microwave/Imager (SSM/I) were used as input algorithms for the time frame July, 1987 to June, 1990. Large disparities are apparent when comparing the NASA algorithm with the Comisco and NORSEX algorithms. Very large differences, some higher than 30 per cent, exist in the marginal ice zones, along the coast, and in the Weddell and Ross Seas Heat fluxes through recurring polynyas were calculated to quantify further differences in the algorithms; however, no conclusive patterns were apparent. No significant change in the extent or area of the ice pack occurred from July, 1987 through June, 1990. Antarctic Ocean, Antarctic regions, Global warming, Sea ice-Antarctic regions.

  8. Concentrations, deposition, and effects of nitrogenous pollutants in selected California ecosystems.

    PubMed

    Bytnerowicz, A; Padgett, P E; Parry, S D; Fenn, M E; Arbaugh, M J

    2001-11-28

    Atmospheric deposition of nitrogen (N) in California ecosystems is ecologically significant and highly variable, ranging from about 1 to 45 kg/ha/year. The lowest ambient concentrations and deposition values are found in the eastern and northern parts of the Sierra Nevada Mountains and the highest in parts of the San Bernardino and San Gabriel Mountains that are most exposed to the Los Angeles air pollution plume. In the Sierra Nevada Mountains, N is deposited mostly in precipitation, although dry deposition may also provide substantial amounts of N. On the western slopes of the Sierra Nevada, the majority of airborne N is in reduced forms as ammonia (NH3) and particulate ammonium (NH4+) from agricultural activities in the California Central Valley. In southern California, most of the N air pollution is in oxidized forms as nitrogen oxides (NOx), nitric acid (HNO3), and particulate nitrate (NO3-) resulting from fossil fuel combustion and subsequent complex photochemical reactions. In southern California, dry deposition of gases and particles provides most (up to 95%) of the atmospheric N to forests and other ecosystems. In the mixed-conifer forest zone, elevated deposition of N may initially benefit growth of vegetation, but chronic effects may be expressed as deterioration of forest health and sustainability. HNO3 vapor alone has a potential for toxic effects causing damage of foliar surfaces of pines and oaks. In addition, dry deposition of predominantly HNO3 has lead to changes in vegetation composition and contamination of ground- and stream water where terrestrial N loading is high. Long-term, complex interactions between N deposition and other environmental stresses such as elevated ozone (O3), drought, insect infestations, fire suppression, or intensive land management practices may affect water quality and sustainability of California forests and other ecosystems.

  9. Concentrations, deposition, and effects of nitrogenous pollutants in selected California ecosystems.

    PubMed

    Bytnerowicz, A; Padgett, P E; Parry, S D; Fenn, M E; Arbaugh, M J

    2001-11-28

    Atmospheric deposition of nitrogen (N) in California ecosystems is ecologically significant and highly variable, ranging from about 1 to 45 kg/ha/year. The lowest ambient concentrations and deposition values are found in the eastern and northern parts of the Sierra Nevada Mountains and the highest in parts of the San Bernardino and San Gabriel Mountains that are most exposed to the Los Angeles air pollution plume. In the Sierra Nevada Mountains, N is deposited mostly in precipitation, although dry deposition may also provide substantial amounts of N. On the western slopes of the Sierra Nevada, the majority of airborne N is in reduced forms as ammonia (NH3) and particulate ammonium (NH4+) from agricultural activities in the California Central Valley. In southern California, most of the N air pollution is in oxidized forms as nitrogen oxides (NOx), nitric acid (HNO3), and particulate nitrate (NO3-) resulting from fossil fuel combustion and subsequent complex photochemical reactions. In southern California, dry deposition of gases and particles provides most (up to 95%) of the atmospheric N to forests and other ecosystems. In the mixed-conifer forest zone, elevated deposition of N may initially benefit growth of vegetation, but chronic effects may be expressed as deterioration of forest health and sustainability. HNO3 vapor alone has a potential for toxic effects causing damage of foliar surfaces of pines and oaks. In addition, dry deposition of predominantly HNO3 has lead to changes in vegetation composition and contamination of ground- and stream water where terrestrial N loading is high. Long-term, complex interactions between N deposition and other environmental stresses such as elevated ozone (O3), drought, insect infestations, fire suppression, or intensive land management practices may affect water quality and sustainability of California forests and other ecosystems. PMID:12805794

  10. Comparison of environmental tobacco smoke (ETS) concentrations generated by an electrically heated cigarette smoking system and a conventional cigarette.

    PubMed

    Tricker, Anthony R; Schorp, Matthias K; Urban, Hans-Jörg; Leyden, Donald; Hagedorn, Heinz-Werner; Engl, Johannes; Urban, Michael; Riedel, Kirsten; Gilch, Gerhard; Janket, Dinamis; Scherer, Gerhard

    2009-01-01

    Smoking conventional lit-end cigarettes results in exposure of nonsmokers to potentially harmful cigarette smoke constituents present in environmental tobacco smoke (ETS) generated by sidestream smoke emissions and exhaled mainstream smoke. ETS constituent concentrations generated by a conventional lit-end cigarette and a newly developed electrically heated cigarette smoking system (EHCSS) that produces only mainstream smoke and no sidestream smoke emissions were investigated in simulated "office" and "hospitality" environments with different levels of baseline indoor air quality. Smoking the EHCSS (International Organisation for Standardization yields: 5 mg tar, 0.3 mg nicotine, and 0.6 mg carbon monoxide) in simulated indoor environments resulted in significant reductions in ETS constituent concentrations compared to when smoking a representative lit-end cigarette (Marlboro: 6 mg tar, 0.5 mg nicotine, and 7 mg carbon monoxide). In direct comparisons, 24 of 29 measured smoke constituents (83%) showed mean reductions of greater than 90%, and 5 smoke constituents (17%) showed mean reductions between 80% and 90%. Gas-vapor phase ETS markers (nicotine and 3-ethenylpyridine) were reduced by an average of 97% (range 94-99%). Total respirable suspended particles, determined by online particle measurements and as gravimetric respirable suspended particles, were reduced by 90% (range 82-100%). The mean and standard deviation of the reduction of all constituents was 94 +/- 4%, indicating that smoking the new EHCSS in simulated "office" and "hospitality" indoor environments resulted in substantial reductions of ETS constituents in indoor air. PMID:18951229

  11. Self-organization by selection: Generation of a metallosupramolecular grid architecture by selection of components in a dynamic library of ligands

    PubMed Central

    Nitschke, Jonathan R.; Lehn, Jean-Marie

    2003-01-01

    Self-organization by selection is implemented in the generation of a tetranuclear [2 × 2] grid-type metallosupramolecular architecture from its components. It occurs through a two-level self-assembly involving two dynamic processes: reversible covalent bound connection and reversible metal ion coordination. Thus, mixing the aminophenol 3, the dialdehyde 4, and zinc acetate generates the grid complex 1a(Zn) via the assembly of the ligand 2a by imine formation and of the grid by zinc(II) binding. When the same process is conducted in a solution containing a mixture of different aminophenol and carbonyl components, the generation of the grid 1a(Zn) drives the selection of the correct components in a virtual dynamic library of ligands, displaying an amplification factor of >100 and a selectivity of >99%. Component exchange as well as reversible protonic modulation of the assembly/disassembly process display the dynamic character of the system and its ability to respond/adapt to changes in environmental conditions. The processes described demonstrate the implementation of a two-level self-organization by selection operating on the dynamic diversity generated by a set of reversibly connected components and driven by the formation of a specific product in a “self-design” fashion. PMID:14517351

  12. Selectivity loss of Pt/CeO{sub 2} PROX catalysts at low CO concentrations: mechanism and active site study.

    SciTech Connect

    Polster, C. S.; Zhang, R.; Cyb, M. T.; Miller, J. T.; Baertsch, C. D.

    2010-07-01

    CO and H{sub 2} oxidation were studied over a series of Pt/CeO{sub 2} catalysts with differing Pt loadings and dispersions. Kinetic rate analysis confirms the presence of dual Langmuir-Hinshelwood (L-H) and Mars and van Krevelen (M-vK) pathways and is used to explain the loss in CO oxidation selectivity at low CO concentrations. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) shows the strong CO coverage dependence on both CO and O{sub 2} concentrations and explains the transition from L-H to M-vK reaction character. Redox site measurements are performed on Pt/CeO{sub 2} catalysts by anaerobic titrations under conditions where the M-vK pathway dominates the reaction rate. Similar redox site densities per interfacial Pt atom suggest that interfacial Pt-O-Ce sites are responsible for M-vK redox activity.

  13. The effect of meat cuts and thermal processing on selected mineral concentration in beef from Holstein-Friesian bulls.

    PubMed

    Czerwonka, Małgorzata; Szterk, Arkadiusz

    2015-07-01

    The impact of meat cuts (nine muscles and liver) and thermal processing on selected mineral (potassium, sodium, phosphorus, magnesium, zinc, iron, including heme form) concentration in beef from Holstein-Friesian bulls was evaluated in the present study. The mineral's content widely varied depending on the tissue type (skeletal muscles/liver, except zinc) and between the different bovine muscles. The greatest diversity between the muscles demonstrated was zinc (3.5-6.9 mg 100 g(-1)f/w) and iron (1.7-2.3 mg 100 g(-1)f/w), however, there were no significant differences in heme iron to total iron ratio (average 74%). Thermal processes conducted on longissimus dorsi muscles also significantly affected mineral concentration. Grilled, roasted and fried bovine meat was characterised by a higher content (by 6-26%) of most studied minerals (except sodium) as compared to raw meat. Sodium levels in processed meat were 16-33% lower than in raw samples.

  14. Determination of inorganic arsenic species by flow injection hydride generation atomic absorption spectrometry with variable sodium tetrahydroborate concentrations*1

    NASA Astrophysics Data System (ADS)

    Sigrist, Mirna E.; Beldoménico, Horacio R.

    2004-07-01

    This work describes a study on the determination of inorganic arsenic species in ground water and synthetic experimental matrices, using a flow injection system with on-line hydride generation device coupled to an atomic absorption spectrometer with flame-heated quartz atomizer (FI HG AAS). Specific trivalent arsenic determination is based on the slow kinetics of As(V) on the hydride generation reaction using sufficiently low concentrations of sodium tetrahydroborate (NaBH 4) as reductant in highly acidic conditions (pH<0). Under these conditions, the efficiency of hydride generation from As(V) is much lower than that from As(III). The pentavalent form is determined by the difference between total inorganic arsenic and As(III). As(V) interferences were studied using As(III) solutions ranging from 0% to 50% of total inorganic As. The optimized NaBH 4 concentration was 0.035% (w/v). The detection limit was 1.4 μg l -1 As(III). As(V) interferences were 6% in the case of water samples with 6 μg l -1 As(III) in the presence of 54 μg l -1 As(V) (i.e. 10% As(III)). Interferences of methylated arsenic species (MMA and DMA) were evaluated. Speciation method was satisfactorily applied to 20 field arsenical water samples from Santa Fe, Argentina, with values ranging from 30 to 308 μg l -1 total As. We found from 0% to 36% As(III) in the 20 field samples. The developed methodology constitutes an economic, simple and reliable way to evaluate inorganic arsenic distribution in underground waters or similar systems with negligible or no content of organoarsenicals.

  15. Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study.

    PubMed

    Spaan, Suzanne; Pronk, Anjoeka; Koch, Holger M; Jusko, Todd A; Jaddoe, Vincent W V; Shaw, Pamela A; Tiemeier, Henning M; Hofman, Albert; Pierik, Frank H; Longnecker, Matthew P

    2015-05-01

    The widespread use of organophosphate (OP) pesticides has resulted in ubiquitous exposure in humans, primarily through their diet. Exposure to OP pesticides may have adverse health effects, including neurobehavioral deficits in children. The optimal design of new studies requires data on the reliability of urinary measures of exposure. In the present study, urinary concentrations of six dialkyl phosphate (DAP) metabolites, the main urinary metabolites of OP pesticides, were determined in 120 pregnant women participating in the Generation R Study in Rotterdam. Intra-class correlation coefficients (ICCs) across serial urine specimens taken at <18, 18-25, and >25 weeks of pregnancy were determined to assess reliability. Geometric mean total DAP metabolite concentrations were 229 (GSD 2.2), 240 (GSD 2.1), and 224 (GSD 2.2) nmol/g creatinine across the three periods of gestation. Metabolite concentrations from the serial urine specimens in general correlated moderately. The ICCs for the six DAP metabolites ranged from 0.14 to 0.38 (0.30 for total DAPs), indicating weak to moderate reliability. Although the DAP metabolite levels observed in this study are slightly higher and slightly more correlated than in previous studies, the low to moderate reliability indicates a high degree of within-person variability, which presents challenges for designing well-powered epidemiological studies. PMID:25515376

  16. Size distribution and concentration of soot generated in oil and gas-fired residential boilers under different combustion conditions

    NASA Astrophysics Data System (ADS)

    Jiménez, Santiago; Barroso, Jorge; Pina, Antonio; Ballester, Javier

    2016-05-01

    In spite of the relevance of residential heating burners in the global emission of soot particles to the atmosphere, relatively little information on their properties (concentration, size distribution) is available in the literature, and even less regarding the dependence of those properties on the operating conditions. Instead, the usual procedure to characterize those emissions is to measure the smoke opacity by several methods, among which the blackening of a paper after filtering a fixed amount of gas (Bacharach test) is predominant. In this work, the size distributions of the particles generated in the combustion of a variety of gaseous and liquid fuels in a laboratory facility equipped with commercial burners have been measured with a size classifier coupled to a particle counter in a broad range of operating conditions (air excesses), with simultaneous determination of the Bacharach index. The shape and evolution of the distribution with progressively smaller oxygen concentrations depends essentially on the state of the fuel: whereas the combustion of the gases results in monomodal distributions that 'shift' towards larger diameters, in the case of the gas-oils an ultrafine mode is always observed, and a secondary mode of coarse particle grows in relevance. In both cases, there is a strong, exponential correlation between the total mass concentration and the Bacharach opacity index, quite similar for both groups of fuels. The empirical expressions proposed may allow other researchers to at least estimate the emissions of numerous combustion facilities routinely characterized by their smoke opacities.

  17. Inhibition of mutant BRAF splice variant signaling by next-generation, selective RAF inhibitors.

    PubMed

    Basile, Kevin J; Le, Kaitlyn; Hartsough, Edward J; Aplin, Andrew E

    2014-05-01

    Vemurafenib and dabrafenib block MEK-ERK1/2 signaling and cause tumor regression in the majority of advanced-stage BRAF(V600E) melanoma patients; however, acquired resistance and paradoxical signaling have driven efforts for more potent and selective RAF inhibitors. Next-generation RAF inhibitors, such as PLX7904 (PB04), effectively inhibit RAF signaling in BRAF(V600E) melanoma cells without paradoxical effects in wild-type cells. Furthermore, PLX7904 blocks the growth of vemurafenib-resistant BRAF(V600E) cells that express mutant NRAS. Acquired resistance to vemurafenib and dabrafenib is also frequently driven by expression of mutation BRAF splice variants; thus, we tested the effects of PLX7904 and its clinical analog, PLX8394 (PB03), in BRAF(V600E) splice variant-mediated vemurafenib-resistant cells. We show that paradox-breaker RAF inhibitors potently block MEK-ERK1/2 signaling, G1/S cell cycle events, survival and growth of vemurafenib/PLX4720-resistant cells harboring distinct BRAF(V600E) splice variants. These data support the further investigation of paradox-breaker RAF inhibitors as a second-line treatment option for patients failing on vemurafenib or dabrafenib.

  18. Selection of the Ground Segment for the Next Generation Space Telescope (NGST) Flight Demonstrator (Nexus)

    NASA Technical Reports Server (NTRS)

    Gal-Edd, Jonathan; Steck, Jane A.; Isaacs, John C., III; Bredeck, Martin J.; Fatig, Curtis Clyde; Zepp, Robert H.; Power, Edward (Technical Monitor)

    2001-01-01

    Nexus was a technology demonstrator project that was designed to bridge from the Hubble Space Telescope (HST) to its successor, the Next Generation Space Telescope (NGST). This paper focuses on the process used in designing the ground segment for Nexus and the lessons learned in its development. Ground station cost drivers were: (1) Contact time, (2) Cost of transporting data between the ground stations and control center, and (3) Cost savings via ground automation. We found that reducing the communication requirement in just the first 100 days could have reduced the total ground station cost by 40%. Contact time cost dwarfed the cost trade between automation development and off-shift operations personnel. Real-time Telemetry and Control (T&C) system analysis was divided into: (1) Potential reuse of the Nexus real-time (T&C) system for NGST, (2) Feasibility of using a 'Finite State-Based Modeling' product, and (3) Selecting a Commercial Off the Shelf (COTS) versus Government Off The Shelf (GOTS) products. We found that each of the products evaluated in detail (ASIST, EPOCH 2000, and ITOS) could adequately support basic mission requirements. Lessons learned were: (1) Include operations at the beginning of the mission, and (2) Develop an operations concept as soon as possible.

  19. Kinetic studies of electrochemical generation of Ag(II) ion and catalytic oxidation of selected organics

    SciTech Connect

    Zawodzinski, C.; Smith, W.H.; Martinez, K.R.

    1993-07-01

    The goal of this research is to develop a method to treat mixed hazardous wastes containing selected organic compounds and heavy metals, including actinide elements. One approach is to destroy the organic via electrochemical oxidation to carbon dioxide, then recover the metal contaminants through normally accepted procedures such as ion exchange, precipitation, etc. The authors have chosen to study the electrochemical oxidation of a simple alcohol, iso-propanol. Much of the recent work reported involved the use of an electron transfer mediator, usually the silver(I)/(II) redox couple. This involved direct electrochemical generation of the mediator at the anode of a divided cell followed by homogeneous reaction of the mediator with the organic compound. In this study the authors have sought to compare the mediated reaction with direct electrochemical oxidation of the organic. In addition to silver(I)/(II) they also looked at the cobalt(II)/(III) redox coupled. In the higher oxidation state both of these metal ions readily hydrolyze in aqueous solution to ultimately form insoluble oxide. The study concluded that in a 6M nitric acid solution at room temperature iso-propanol can be oxidized to carbon dioxide and acetic acid. Acetic acid is a stable intermediate and resists further oxidation. The presence of Co(III) enhances the rate or efficiency of the reaction.

  20. Transient dominant selection for the modification and generation of recombinant infectious bronchitis coronaviruses.

    PubMed

    Keep, Sarah M; Bickerton, Erica; Britton, Paul

    2015-01-01

    We have developed a reverse genetics system for the avian coronavirus infectious bronchitis virus (IBV) in which a full-length cDNA corresponding to the IBV genome is inserted into the vaccinia virus genome under the control of a T7 promoter sequence. Vaccinia virus as a vector for the full-length IBV cDNA has the advantage that modifications can be introduced into the IBV cDNA using homologous recombination, a method frequently used to insert and delete sequences from the vaccinia virus genome. Here, we describe the use of transient dominant selection as a method for introducing modifications into the IBV cDNA; this has been successfully used for the substitution of specific nucleotides, deletion of genomic regions, and the exchange of complete genes. Infectious recombinant IBVs are generated in situ following the transfection of vaccinia virus DNA, containing the modified IBV cDNA, into cells infected with a recombinant fowlpox virus expressing T7 DNA-dependent RNA polymerase.

  1. Selective and efficient extraction of recombinant proteins from the periplasm of Escherichia coli using low concentrations of chemicals.

    PubMed

    Jalalirad, Reza

    2013-10-01

    Experiments were conducted to determine chemicals at low concentrations, which can be utilized for selective release of periplasmic proteins. It was revealed that 80-100 % of the activity of alpha-amylase, beta-lactamase, and Fab D1.3 was retained in the presence of 0.05 and 0.1 % Triton X-100, 0.1 % Tween 20, 0.1 % DOC, 0.01 % BAC, 0.01 % CTAB, 10 mM EDTA, 1 mM and 10 mM DEA, 10 mM NTA, 0.1 and 1 % SHMP, 200 mM urea, 100-500 mM GndCl, and 1 % solvents (hexane, xylene, toluene, benzene, pyridine and isoamyl alcohol). Performance of these chemicals, recognized as generally safe, for selective release of proteins from the periplasm of Escherichia coli was investigated. DOC was a general and very efficient agent, and at concentrations as low as 0.05, 0.1, and 0.025 %, released beta-lactamase, alpha-amylase, and Fab D1.3 selectively with yield factors of 2.7, 2.3, and 3.6 times greater than osmotic shock procedure, respectively. EDTA (1 and 10 mM) discharged Fab D1.3 with efficiency more than osmotic shock (target protein yield of 110 and 138 %, correspondingly). Isoamyl alcohol (10 % v/v) was effective for periplasmic release of alpha-amylase and particularly Fab D1.3, with target protein yields of 75 and 168 %, respectively.

  2. Design and optimization of a multi-element piezoelectric transducer for mode-selective generation of guided waves

    NASA Astrophysics Data System (ADS)

    Yazdanpanah Moghadam, Peyman; Quaegebeur, Nicolas; Masson, Patrice

    2016-07-01

    A novel multi-element piezoelectric transducers (MEPT) is designed, optimized, machined and experimentally tested to improve structural health monitoring systems for mode-selective generation of guided waves (GW) in an isotropic structure. GW generation using typical piezoceramics makes the signal processing and consequently damage detection very complicated because at any driving frequency at least two fundamental symmetric (S 0) and antisymmetric (A 0) modes are generated. To prevent this, mode selective transducer design is proposed based on MEPT. A numerical method is first developed to extract the interfacial stress between a single piezoceramic element and a host structure and then used as the input of an analytical model to predict the GW propagation through the thickness of an isotropic plate. Two novel objective functions are proposed to optimize the interfacial shear stress for both suppressing unwanted mode(s) and maximizing the desired mode. Simplicity and low manufacturing cost are two main targets driving the design of the MEPT. A prototype MEPT is then manufactured using laser micro-machining. An experimental procedure is presented to validate the performances of the MEPT as a new solution for mode-selective GW generation. Experimental tests illustrate the high capability of the MEPT for mode-selective GW generation, as unwanted mode is suppressed by a factor up to 170 times compared with the results obtained with a single piezoceramic.

  3. Equilibration times, compound selectivity, and stability of diffusion samplers for collection of ground-water VOC concentrations

    USGS Publications Warehouse

    Vroblesky, D.A.; Campbell, T.R.

    2001-01-01

    Vapor-filled polyethylene diffusion samplers (typically used to locate discharge zones of volatile organic compound contaminated ground water beneath streams and lakes) and water-filled polyethylene diffusion bag samplers (typically used to obtain volatile organic compound concentrations in ground-water at wells) were tested to determine compound selectivity, equilibration times, and sample stability. The aqueous concentrations of several volatile organic compounds obtained from within water-filled diffusion samplers closely matched concentrations in ambient water outside the samplers. An exception was methyl-tert-butyl ether, which was detectable, but not reliably quantifiable using the diffusion samplers. The samplers equilibrated to a variety of volatile organic compounds within 24 h for vapor-filled passive diffusion vial samplers and within 48 h for water-filled passive diffusion bag samplers. Under field conditions, however, a longer equilibration time may be required to account for environmental disturbances caused by sampler deployment. An equilibrium period for both vapor- and water-filled diffusion samplers of approximately 2 weeks probably is adequate for most investigations in sandy formations. Longer times may be required for diffusion-sampler equilibration in poorly permeable sediment. The vapor-filled samplers should be capped and water from the diffusion bag samplers should be transferred to sampling vials immediately upon recovery to avoid volatilization losses of the gasses. ?? 2001 Elsevier Science Ltd.

  4. Experience with a third generation recombinant factor VIII concentrate (Advate) for immune tolerance induction in patients with haemophilia A.

    PubMed

    Valentino, L A; Recht, M; Dipaola, J; Shapiro, A D; Pipe, S W; Ewing, N; Urgo, J; Bullock, T; Simmons, M; Deguzman, C

    2009-05-01

    The development of an inhibitor represents one of the most challenging complications in patients with haemophilia A. Optimal management is immune tolerance induction (ITI), typically through the administration of high doses of factor VIII (FVIII) concentrate. Among 12 patients who underwent ITI using Advate, a third-generation recombinant FVIII product that is free of animal and human protein additives, tolerance was achieved in nine (75%), including seven of 10 patients (70%) with high-titre inhibitors. ITI is ongoing in two patients and not yet successful; immune tolerance failed in the third patient. The median time to success was 4.0 months for group as a whole and for patients with high-titre inhibitors. Treatment was well tolerated, and no adverse events were observed. Advate was found to be equivalent to other FVIII products with regard to both ITI success rates and the incidence of adverse effects when used in these immune tolerance regimens. PMID:19298383

  5. In silico and in vitro analyses of the angiotensin-I converting enzyme inhibitory activity of hydrolysates generated from crude barley (Hordeum vulgare) protein concentrates.

    PubMed

    Gangopadhyay, Nirupama; Wynne, Kieran; O'Connor, Paula; Gallagher, Eimear; Brunton, Nigel P; Rai, Dilip K; Hayes, Maria

    2016-07-15

    Angiotensin-I-converting enzyme (ACE-I) plays a key role in control of hypertension, and type-2 diabetes mellitus, which frequently co-exist. Our current work utilised in silico methodologies and peptide databases as tools for predicting release of ACE-I inhibitory peptides from barley proteins. Papain was the enzyme of choice, based on in silico analysis, for experimental hydrolysis of barley protein concentrate, which was performed at the enzyme's optimum conditions (60 °C, pH 6.0) for 24 h. The generated hydrolysate was subjected to molecular weight cut-off (MWCO) filtration, following which the non-ultrafiltered hydrolysate (NUFH), and the generated 3 kDa and 10 kDa MWCO filtrates were assessed for their in vitro ACE-I inhibitory activities. The 3 kDa filtrate (1 mg/ml), that demonstrated highest ACE-I inhibitory activity of 70.37%, was characterised in terms of its peptidic composition using mass spectrometry and 1882 peptides derived from 61 barley proteins were identified, amongst which 15 peptides were selected for chemical synthesis based on their predicted ACE-I inhibitory properties. Of the synthesized peptides, FQLPKF and GFPTLKIF were most potent, demonstrating ACE-I IC50 values of 28.2 μM and 41.2 μM respectively. PMID:26948626

  6. New generation nuclear fuel structures: Dense particles in selectively soluble matrix

    NASA Astrophysics Data System (ADS)

    Devlin, Dave; Jarvinen, Gordon; Patterson, Brian; Pattillo, Steve; Valdez, James; Liu, X.-Y.; Phillips, Jonathan

    2009-11-01

    We have developed a technology for dispersing sub-millimeter sized fuel particles within a bulk matrix that can be selectively dissolved. This may enable the generation of advanced nuclear fuels with easy separation of actinides and fission products. The large kinetic energy of the fission products results in most of them escaping from the sub-millimeter sized fuel particles and depositing in the matrix during burning of the fuel in the reactor. After the fuel is used and allowed to cool for a period of time, the matrix can be dissolved and the fission products removed for disposal while the fuel particles are collected by filtration for recycle. The success of such an approach would meet a major goal of the GNEP program to provide advanced recycle technology for nuclear energy production. The benefits of such an approach include (1) greatly reduced cost of the actinide/fission product separation process, (2) ease of recycle of the fuel particles, and (3) a radiation barrier to prevent theft or diversion of the recycled fuel particles during the time they are re-fabricated into new fuel. In this study we describe a method to make surrogate nuclear fuels of micrometer scale W (shell)/Mo (core) or HfO 2 particles embedded in an MgO matrix that allows easy separation of the fission products and their embedded particles. In brief, the method consists of physically mixing W-Mo or hafnia particles with an MgO precursor. Heating the mixture, in air or argon, without agitation, to a temperature is required for complete decomposition of the precursor. The resulting material was examined using chemical analysis, scanning electron microscopy, X-ray diffraction and micro X-ray computed tomography and found to consist of evenly dispersed particles in an MgO + matrix. We believe this methodology can be extended to actinides and other matrix materials.

  7. New generation nuclear fuel structures: dense particles in selectively soluble matrix

    SciTech Connect

    Sickafus, Kurt E; Devlin, David J; Jarvinen, Gordon D; Patterson, Brian M; Pattillo, Steve G; Valdez, James; Phillips, Jonathan

    2009-01-01

    We have developed a technology for dispersing sub-millimeter sized fuel particles within a bulk matrix that can be selectively dissolved. This may enable the generation of advanced nuclear fuels with easy separation of actinides and fission products. The large kinetic energy of the fission products results in most of them escaping from the sub-millimeter sized fuel particles and depositing in the matrix during burning of the fuel in the reactor. After the fuel is used and allowed to cool for a period of time, the matrix can be dissolved and the fission products removed for disposal while the fuel particles are collected by filtration for recycle. The success of such an approach would meet a major goal of the GNEP program to provide advanced recycle technology for nuclear energy production. The benefits of such an approach include (1) greatly reduced cost of the actinide/fission product separation process, (2) ease of recycle of the fuel particles, and (3) a radiation barrier to prevent theft or diversion of the recycled fuel particles during the time they are re-fabricated into new fuel. In this study we describe a method to make surrogate nuclear fuels of micrometer scale W (shell)/Mo (core) or HfO2 particles embedded in an MgO matrix that allows easy separation of the fission products and their embedded particles. In brief, the method consists of physically mixing W-Mo or hafnia particles with an MgO precursor. Heating the mixture, in air or argon, without agitation, to a temperature is required for complete decomposition of the precursor. The resulting material was examined using chemical analysis, scanning electron microscopy, X-ray diffraction and micro X-ray computed tomography and found to consist of evenly dispersed particles in an MgO + matrix. We believe this methodology can be extended to actinides and other matrix materials.

  8. A Rich Morphological Diversity of Biosaline Drying Patterns Is Generated by Different Bacterial Species, Different Salts and Concentrations: Astrobiological Implications

    NASA Astrophysics Data System (ADS)

    Gómez Gómez, José María; Medina, Jesús; Rull, Fernando

    2016-07-01

    Biosaline formations (BSFs) are complex self-organized biomineral patterns formed by "hibernating" bacteria as the biofilm that contains them dries out. They were initially described in drying biofilms of Escherichia coli cells + NaCl. Due to their intricate 3-D morphology and anhydrobiosis, these biomineralogical structures are of great interest in astrobiology. Here we report experimental data obtained with various alkali halide salts (NaF, NaCl, NaBr, LiCl, KCl, CsCl) on BSF formation with E. coli and Bacillus subtilis bacteria at two saline concentrations: 9 and 18 mg/mL. Our results indicate that, except for LiCl, which is inactive, all the salts assayed are active during BSF formation and capable of promoting the generation of distinctive drying patterns at each salt concentration. Remarkably, the BSFs produced by these two bacterial species produce characteristic architectural hallmarks as the BSF dries. The potential biogenicity of these biosaline drying patterns is studied, and the astrobiological implications of these findings are discussed.

  9. Effects of Fibrinogen Concentrate on Thrombin Generation, Thromboelastometry Parameters, and Laboratory Coagulation Testing in a 24-Hour Porcine Trauma Model

    PubMed Central

    Zentai, Christian; Solomon, Cristina; van der Meijden, Paola E. J.; Spronk, Henri M. H.; Schnabel, Jonas; Rossaint, Rolf

    2015-01-01

    Introduction: In a 24-hour porcine model of liver injury, we showed that fibrinogen supplementation does not downregulate endogenous fibrinogen synthesis. Here we report data from the same study showing the impact of fibrinogen on coagulation variables. Materials and Methods: Coagulopathy was induced in 20 German land race pigs by hemodilution and blunt liver injury. Animals randomly received fibrinogen concentrate (100 mg/kg) or saline. Coagulation parameters were assessed and thromboelastometry (ROTEM) was performed. Results: Fibrinogen concentrate significantly reduced the prolongations of EXTEM clotting time, EXTEM clot formation time, and prothrombin time induced by hemodilution and liver injury. A decrease in clot strength was also ameliorated. Endogenous thrombin potential was significantly higher in the fibrinogen group than in the control group, 20 minutes (353 ± 24 vs 289 ± 22 nmol/L·min; P < .05) and 100 minutes (315 ± 40 vs 263 ± 38 nmol/L·min; P < .05) after the start of infusion. However, no significant between-group differences were seen in other thrombin generation parameters or in d-dimer or thrombin–antithrombin levels. Fibrinogen–platelet binding was reduced following liver injury, with no significant differences between groups. No significant between-group differences were observed in any parameter at ∼12 and ∼24 hours. Conclusion: This study suggests that, in trauma, fibrinogen supplementation may shorten some measurements of the speed of coagulation initiation and produce a short-lived increase in endogenous thrombin potential, potentially through increased clotting substrate availability. Approximately 12 and 24 hours after starting fibrinogen concentrate/saline infusion, all parameters measured in this study were comparable in the 2 study groups. PMID:25948634

  10. Electrochemical activation and inhibition of neuromuscular systems through modulation of ion concentrations with ion-selective membranes

    NASA Astrophysics Data System (ADS)

    Song, Yong-Ak; Melik, Rohat; Rabie, Amr N.; Ibrahim, Ahmed M. S.; Moses, David; Tan, Ara; Han, Jongyoon; Lin, Samuel J.

    2011-12-01

    Conventional functional electrical stimulation aims to restore functional motor activity of patients with disabilities resulting from spinal cord injury or neurological disorders. However, intervention with functional electrical stimulation in neurological diseases lacks an effective implantable method that suppresses unwanted nerve signals. We have developed an electrochemical method to activate and inhibit a nerve by electrically modulating ion concentrations in situ along the nerve. Using ion-selective membranes to achieve different excitability states of the nerve, we observe either a reduction of the electrical threshold for stimulation by up to approximately 40%, or voluntary, reversible inhibition of nerve signal propagation. This low-threshold electrochemical stimulation method is applicable in current implantable neuroprosthetic devices, whereas the on-demand nerve-blocking mechanism could offer effective clinical intervention in disease states caused by uncontrolled nerve activation, such as epilepsy and chronic pain syndromes.

  11. Comparative Mutant Prevention Concentrations of Pradofloxacin and Other Veterinary Fluoroquinolones Indicate Differing Potentials in Preventing Selection of Resistance†

    PubMed Central

    Wetzstein, H.-G.

    2005-01-01

    Pradofloxacin (PRA) is an 8-cyano-fluoroquinolone (FQ) being developed to treat bacterial infections in dogs and cats. Its mutant prevention concentrations (MPC) were determined for Escherichia coli ATCC 8739 at 0.225 μg/ml, and for Staphylococcus aureus ATCC 6538 at 0.55 μg/ml. At drug concentrations equal to or above the MPC, growth (implying selective clonal expansion) of first-step FQ-resistant variants, naturally present in large bacterial populations, was inhibited. MPC90 derived from 10 clinical isolates each of E. coli and Staphylococcus intermedius, the latter species being of greater clinical relevance than S. aureus in companion-animal medicine, amounted to 0.2 to 0.225 and 0.30 to 0.35 μg/ml, respectively. MPCs of other veterinary FQs were assessed to determine relative in vitro potencies. The MPCs of marbofloxacin, enrofloxacin, danofloxacin, sarafloxacin, orbifloxacin, and difloxacin were 1.2-, 1.4-, 2.3-, 2.4-, 5-, and 7-fold higher than the MPC of PRA for E. coli ATCC 8739, and 6-, 6-, 19-, 15-, 15-, and 31-fold higher than the MPC of PRA for S. aureus ATCC 6538, respectively. MPC curves revealed a pronounced heterogeneity in susceptibility within populations of ≥4 × 109 CFU employed, extending to 10-fold above the MICs. The duration of incubation and, for S. aureus, inoculum density profoundly affected the MPCs. With appropriate dosing, PRA may combine high therapeutic efficacy with a high potential for restricting the selection for FQ resistance under field conditions in the species analyzed. PMID:16189094

  12. Comparative mutant prevention concentrations of pradofloxacin and other veterinary fluoroquinolones indicate differing potentials in preventing selection of resistance.

    PubMed

    Wetzstein, H-G

    2005-10-01

    Pradofloxacin (PRA) is an 8-cyano-fluoroquinolone (FQ) being developed to treat bacterial infections in dogs and cats. Its mutant prevention concentrations (MPC) were determined for Escherichia coli ATCC 8739 at 0.225 microg/ml, and for Staphylococcus aureus ATCC 6538 at 0.55 microg/ml. At drug concentrations equal to or above the MPC, growth (implying selective clonal expansion) of first-step FQ-resistant variants, naturally present in large bacterial populations, was inhibited. MPC(90) derived from 10 clinical isolates each of E. coli and Staphylococcus intermedius, the latter species being of greater clinical relevance than S. aureus in companion-animal medicine, amounted to 0.2 to 0.225 and 0.30 to 0.35 microg/ml, respectively. MPCs of other veterinary FQs were assessed to determine relative in vitro potencies. The MPCs of marbofloxacin, enrofloxacin, danofloxacin, sarafloxacin, orbifloxacin, and difloxacin were 1.2-, 1.4-, 2.3-, 2.4-, 5-, and 7-fold higher than the MPC of PRA for E. coli ATCC 8739, and 6-, 6-, 19-, 15-, 15-, and 31-fold higher than the MPC of PRA for S. aureus ATCC 6538, respectively. MPC curves revealed a pronounced heterogeneity in susceptibility within populations of > or =4 x 10(9) CFU employed, extending to 10-fold above the MICs. The duration of incubation and, for S. aureus, inoculum density profoundly affected the MPCs. With appropriate dosing, PRA may combine high therapeutic efficacy with a high potential for restricting the selection for FQ resistance under field conditions in the species analyzed.

  13. Evaluation of synthetic water-soluble metal-binding polymers with ultrafiltration for selective concentration of americium and plutonium

    SciTech Connect

    Smith, B.F.; Gibson, R.R.; Jarvinen, G.D.; Jones, M.M.; Lu, M.T.; Robison, T.W.; Schroeder, N.C.; Stalnaker, N.

    1997-12-31

    Routine counting methods and ICP-MS are unable to directly measure the new US Department of Energy (DOE) regulatory level for discharge waters containing alpha-emitting radionuclides of 30 pCi/L total alpha or the 0.05 pCi/L regulatory level for Pu or Am activity required for surface waters at the Rocky Flats site by the State of Colorado. This inability indicates the need to develop rapid, reliable, and robust analytical techniques for measuring actinide metal ions, particularly americium and plutonium. Selective separation or preconcentration techniques would aid in this effort. Water-soluble metal-binding polymers in combination with ultrafiltration are shown to be an effective method for selectively removing dilute actinide ions from acidic solutions of high ionic strength. The actinide-binding properties of commercially available water-soluble polymers and several polymers which have been reported in the literature were evaluated. The functional groups incorporated in the polymers were pyrrolidone, amine, oxime, and carboxylic, phosphonic, or sulfonic acid. The polymer containing phosphonic acid groups gave the best results with high distribution coefficients and concentration factors for {sup 241}Am(III) and {sup 238}Pu(III)/(IV) at pH 4 to 6 and ionic strengths of 0.1 to 4.

  14. Development of a new chemically modified carbon paste electrode for selective determination of urinary and serum oxalate concentration.

    PubMed

    Soleymanpour, Ahmad; Shafaatian, Bita; Mirfakhraei, Homeira Sadat; Rezaeifard, Abdolreza

    2013-11-15

    The construction and evaluation of a novel modified carbon paste electrode with high selectivity toward oxalate ion are described. The constructed carbon paste potentiometric sensor for oxalate ion is based on the use of a zirconium salan complex as a good ionophore in the carbon paste matrix. The electrode exhibits a Nernstian slope of 29.1 mV/decade to oxalate ion over a wide concentration range from 1.5×10(-6) to 3.9 ×10(-2) mol L(-1) with a low detection limit of 7.0×10(-7) mol L(-1). The electrode possesses fast response time, satisfactory reproducibility, appropriate lifetime, and most importantly, good selectivity toward C2O4(2-) relative to a variety of common anions. The potentiometric response of the electrode is independent of the pH of the test solution in the pH range 2.5-8.0. The modified carbon paste electrode was successfully applied as an indicator electrode in potentiometric titration and potentiometric determination of oxalate ion in mineral water, blood serum and urine samples.

  15. Selecting optimal monitoring site locations for peak ambient particulate material concentrations using the MM5-CAMx4 numerical modelling system.

    PubMed

    Sturman, Andrew; Titov, Mikhail; Zawar-Reza, Peyman

    2011-01-15

    Installation of temporary or long term monitoring sites is expensive, so it is important to rationally identify potential locations that will achieve the requirements of regional air quality management strategies. A simple, but effective, numerical approach to selecting ambient particulate matter (PM) monitoring site locations has therefore been developed using the MM5-CAMx4 air pollution dispersion modelling system. A new method, 'site efficiency,' was developed to assess the ability of any monitoring site to provide peak ambient air pollution concentrations that are representative of the urban area. 'Site efficiency' varies from 0 to 100%, with the latter representing the most representative site location for monitoring peak PM concentrations. Four heavy pollution episodes in Christchurch (New Zealand) during winter 2005, representing 4 different aerosol dispersion patterns, were used to develop and test this site assessment technique. Evaluation of the efficiency of monitoring sites was undertaken for night and morning aerosol peaks for 4 different particulate material (PM) spatial patterns. The results demonstrate that the existing long term monitoring site at Coles Place is quite well located, with a site efficiency value of 57.8%. A temporary ambient PM monitoring site (operating during winter 2006) showed a lower ability to capture night and morning peak aerosol concentrations. Evaluation of multiple site locations used during an extensive field campaign in Christchurch (New Zealand) in 2000 indicated that the maximum efficiency achieved by any site in the city would be 60-65%, while the efficiency of a virtual background site is calculated to be about 7%. This method of assessing the appropriateness of any potential monitoring site can be used to optimize monitoring site locations for any air pollution measurement programme.

  16. Prediction of suspended-sediment concentrations at selected sites in the Fountain Creek watershed, Colorado, 2008-09

    USGS Publications Warehouse

    Stogner, Robert W.; Nelson, Jonathan M.; McDonald, Richard R.; Kinzel, Paul J.; Mau, David P.

    2013-01-01

    In 2008, the U.S. Geological Survey (USGS), in cooperation with Pikes Peak Area Council of Governments, Colorado Water Conservation Board, Colorado Springs City Engineering, and the Lower Arkansas Valley Water Conservancy District, began a small-scale pilot study to evaluate the effectiveness of the use of a computational model of streamflow and suspended-sediment transport for predicting suspended-sediment concentrations and loads in the Fountain Creek watershed in Colorado. Increased erosion and sedimentation damage have been identified by the Fountain Creek Watershed Plan as key problems within the watershed. A recommendation in the Fountain Creek Watershed plan for management of the basin is to establish measurable criteria to determine if progress in reducing erosion and sedimentation damage is being made. The major objective of this study was to test a computational method to predict local suspended-sediment loads at two sites with different geomorphic characteristics in order to evaluate the feasibility of using such an approach to predict local suspended-sediment loads throughout the entire watershed. Detailed topographic surveys, particle-size data, and suspended-sediment samples were collected at two gaged sites: Monument Creek above Woodmen Road at Colorado Springs, Colorado (USGS gage 07103970), and Sand Creek above mouth at Colorado Springs, Colorado (USGS gage 07105600). These data were used to construct three-dimensional computational models of relatively short channel reaches at each site. The streamflow component of these models predicted a spatially distributed field of water-surface elevation, water velocity, and bed shear stress for a range of stream discharges. Using the model predictions, along with measured particle sizes, the sediment-transport component of the model predicted the suspended-sediment concentration throughout the reach of interest. These computed concentrations were used with predicted flow patterns and channel morphology to

  17. Effects of coenzyme Q(10) administration on its tissue concentrations, mitochondrial oxidant generation, and oxidative stress in the rat.

    PubMed

    Kwong, Linda K; Kamzalov, Sergey; Rebrin, Igor; Bayne, Anne-Cécile V; Jana, Chandan K; Morris, Paul; Forster, Michael J; Sohal, Rajindar S

    2002-09-01

    Coenzyme Q (CoQ(10)) is a component of the mitochondrial electron transport chain and also a constituent of various cellular membranes. It acts as an important in vivo antioxidant, but is also a primary source of O(2)(-*)/H(2)O(2) generation in cells. CoQ has been widely advocated to be a beneficial dietary adjuvant. However, it remains controversial whether oral administration of CoQ can significantly enhance its tissue levels and/or can modulate the level of oxidative stress in vivo. The objective of this study was to determine the effect of dietary CoQ supplementation on its content in various tissues and their mitochondria, and the resultant effect on the in vivo level of oxidative stress. Rats were administered CoQ(10) (150 mg/kg/d) in their diets for 4 and 13 weeks; thereafter, the amounts of CoQ(10) and CoQ(9) were determined by HPLC in the plasma, homogenates of the liver, kidney, heart, skeletal muscle, brain, and mitochondria of these tissues. Administration of CoQ(10) increased plasma and mitochondria levels of CoQ(10) as well as its predominant homologue CoQ(9). Generally, the magnitude of the increases was greater after 13 weeks than 4 weeks. The level of antioxidative defense enzymes in liver and skeletal muscle homogenates and the rate of hydrogen peroxide generation in heart, brain, and skeletal muscle mitochondria were not affected by CoQ supplementation. However, a reductive shift in plasma aminothiol status and a decrease in skeletal muscle mitochondrial protein carbonyls were apparent after 13 weeks of supplementation. Thus, CoQ supplementation resulted in an elevation of CoQ homologues in tissues and their mitochondria, a selective decrease in protein oxidative damage, and an increase in antioxidative potential in the rat.

  18. Comparison of vapor concentrations of volatile organic compounds with ground-water concentrations of selected contaminants in sediments beneath the Sudbury River, Ashland, Massachusetts, 2000

    USGS Publications Warehouse

    Campbell, J.P.; Lyford, F.P.; Willey, Richard E.

    2002-01-01

    A mixed plume of contaminants in ground water, including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and metals, near the former Nyanza property in Ashland, Massachusetts, discharges to the Sudbury River upstream and downstream of Mill Pond and a former mill raceway. Polyethylene-membrane vapor-diffusion (PVD) samplers were installed in river-bottom sediments to determine if PVD samplers provide an alternative to ground-water sampling from well points for identifying areas of detectable concentrations of contaminants in sediment pore water near the ground-water and surface-water interface. In August and September 2000, the PVD samplers were installed near well points at depths of 8 to 12 inches in both fine and coarse sediments, whereas the well points were installed at depths of 1 to 5 feet in coarse sediments only. Comparison between vapor and water samples at 29 locations upstream from Mill Pond show that VOC vapor concentrations from PVD samplers in coarse river-bottom sediments are more likely to correspond to ground-water concentrations from well points than PVD samplers installed in fine sediments. Significant correlations based on Kendall's Tau were shown between vapor and ground-water concentrations for trichloroethylene and chlorobenzene for PVD samplers installed in coarse sediments where the fine organic layer that separated the two sampling depths was 1 foot or less in thickness. VOC concentrations from vapor samples also were compared to VOC, SVOC, and metals concentrations from ground-water samples at 10 well points installed upstream and downstream from Mill Pond, and in the former mill raceway. Chlorobenzene vapor concentrations correlated significantly with ground-water concentrations for 5 VOCs, 2 SVOCs, and 10 metals. Trichloroethylene vapor concentrations did not correlate with any of the other ground-water constituents analyzed at the 10 well points. Chlorobenzene detected by use of PVD samplers appears to be a

  19. Supercontinuum generation using a selectively water-filled photonic crystal fiber for enhancement in the visible spectral region

    NASA Astrophysics Data System (ADS)

    Yoshida, Eiichi; Wada, Akira; Karasawa, Naoki

    2016-07-01

    We generated a supercontinuum from a selectively water-filled photonic crystal fiber (PCF) for enhancement in the visible spectral region using an optical pulse from a Ti:sapphire oscillator at 804 nm. We prepared a 7-cm-long fused silica PCF, where the holes adjacent to the central core were filled with water, using a UV-curable adhesive to close holes selectively before filling holes with water by capillary force. Compared with that of the PCF without water, the group velocity dispersion curve of the selectively water-filled PCF became flatter near 800 nm and the intensity in the visible spectral region of the supercontinuum became higher and more uniform. The spectra simulated using the calculated dispersion properties of the selectively water-filled PCF showed good agreement with the experimental spectra.

  20. Metal concentrations in selected brands of canned fish in Nigeria: estimation of dietary intakes and target hazard quotients.

    PubMed

    Iwegbue, Chukwujindu M A

    2015-03-01

    The concentrations of metals (Cd, Pb, Ni, Cr, Cu, Co, Fe, Mn, and Zn) were determined in selected brands of canned mackerel, sardine, and tuna in Nigeria with a view to providing information on the dietary intakes of metals and lifelong health hazards associated with the consumption of these products. The concentrations of metals were determined by using atomic absorption spectrometry after acid digestion. The mean concentrations of metals in canned mackerel, sardine, and tuna were found as 0.04-0.58, 0.06-0.44, 0.32-0.83 μg/g for Cd; 0.05-2.82, 0.70-2.98, 0.23-2.56 μg/g for Pb, 1.33-11.33, <0.20-17.53, nd-34.2 μg/g for Ni, 0.49-3.79, 0.22-1.89, 0.66-14.39 μg/g for Cr, 0.33-0.92, 0.03-1.51, <0.08-1.31 μg/g for Cu, 0.11-2.17, nd-0.75, 0.14-0.50 μg/g for Co, 6.45-26.90, 6.06-53.54, 3.06-95.78 μg/g for Fe, 2.30-3.84, 0.95-21.78, 1.65-2.33 μg/g for Mn, 1.15-7.19, 3.60-17.88, 1.21-5.35 μg/g for Zn, respectively. The mean concentrations of Cd, Pb, and Fe in some of these brands of canned fish were above their permissible limits while other metals occurred at levels below their permissible limits. The estimated daily intakes of metals from consumption of 20.8 g fish per day by a 60 kg body weight adult were below the provisional tolerable daily intakes for Cd, Pb, Ni, Cr, and Cu and recommended daily intakes for Co, Fe, Mn, and Zn. The estimated target hazard quotients of the examined metals were less than 1 in the majority of the samples indicating no long-term health hazard at the present circumstance. PMID:25655121

  1. Body composition and amino acid concentrations of select birds and mammals consumed by cats in northern and central California.

    PubMed

    Kremen, N A; Calvert, C C; Larsen, J A; Baldwin, R A; Hahn, T P; Fascetti, A J

    2013-03-01

    The diet of the feral domestic cat consists of primarily birds and small mammals, but the nutritional composition is relatively unknown. Because of the increasing popularity of natural diets for cats and other wild captive carnivores, the purpose of this study was to describe the body composition and AA concentrations of select birds and small mammals in northern and central California: wild-caught mice (n = 7), Norway rats (n = 2), roof rats (n = 2), voles (n = 4), moles (n = 2), gophers (n = 3), and birds (n = 4). Body water, crude fat (CFa), CP, ash, and AA composition for each specimen were determined. Results are reported as mean ± SD. All results are reported on a DM basis except body water (as-is basis) and AA (g/16 g N). Combined, carcasses had this mean composition: 67.35 ± 3.19% water, 11.72 ± 6.17% CFa, 62.19 ± 7.28% CP, and 14.83 ± 2.66% ash. Concentrations of Arg, Tau, Cys, and Met were 5.63 ± 0.46, 0.92 ± 0.33, 1.91 ± 0.89, and 1.82 ± 0.19 g/16 g N, respectively. Using NRC physiologic fuel values for CP, CFa, and carbohydrate by difference, the combined average energy content of the carcasses was 3,929 kcal/kg DM, but the fiber content was not determined. With the exception of mice and rats, little historical data exist regarding the body and AA composition of many of the species analyzed in this study. Wild-caught mice and rats were composed of less fat but more ash compared with previously reported data in their purpose-bred counterparts. The CP content of mice in this study was similar to previous reports in purpose-bred mice. The CP content of rats was similar or slightly greater compared with historical findings in purpose-bred rats. The N content of rats and AA concentrations on a per-N basis for both rats and mice were similar to previously published data on purpose-bred rodents. The discrepancies in nutrient composition, especially fat concentration, indicate that using purpose-bred animals to represent the diet of the feral domestic

  2. Sulfate and organic matter concentration in relation to hydrogen sulfide generation at inert solid waste landfill site - Limit value for gypsum.

    PubMed

    Asakura, Hiroshi

    2015-09-01

    In order to suggest a limit value for gypsum (CaSO4) for the suppression of hydrogen sulfide (H2S) generation at an inert solid waste landfill site, the relationship between raw material (SO4 and organic matter) for H2S generation and generated H2S concentration, and the balance of raw material (SO4) and product (H2S) considering generation and outflow were investigated. SO4 concentration should be less than approximately 100mg-SO4/L in order to suppress H2S generation to below 2000ppm. Total organic carbon (TOC) concentration should be less than approximately 200mg-C/L assuming a high SO4 concentration. The limit value for SO4 in the ground is 60mg-SO4/kg with 0.011wt% as gypsum dihydrate, i.e., approximately 1/10 of the limit value in inert waste as defined by the EU Council Decision (560mg-SO4/kg-waste). The limit value for SO4 in inert waste as defined by the EU Council Decision is high and TOC is strictly excluded. The cumulative amount of SO4 outflow through the liquid phase is much larger than that through the gas phase. SO4 concentration in pore water decreases with time, reaching half the initial concentration around day 100. SO4 reduction by rainfall can be expected in the long term.

  3. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession. PMID:16623137

  4. Discrete wavelength selection for the optical readout of a metamaterial biosensing system for glucose concentration estimation via a support vector regression model.

    PubMed

    Teutsch, T; Mesch, M; Giessen, H; Tarin, C

    2015-01-01

    In this contribution, a method to select discrete wavelengths that allow an accurate estimation of the glucose concentration in a biosensing system based on metamaterials is presented. The sensing concept is adapted to the particular application of ophthalmic glucose sensing by covering the metamaterial with a glucose-sensitive hydrogel and the sensor readout is performed optically. Due to the fact that in a mobile context a spectrometer is not suitable, few discrete wavelengths must be selected to estimate the glucose concentration. The developed selection methods are based on nonlinear support vector regression (SVR) models. Two selection methods are compared and it is shown that wavelengths selected by a sequential forward feature selection algorithm achieves an estimation improvement. The presented method can be easily applied to different metamaterial layouts and hydrogel configurations.

  5. Concentrations, and Estimated Loads and Yields of Total Nitrogen and Total Phosphorus at Selected Stations in Kentucky, 1979-2004

    USGS Publications Warehouse

    Crain, Angela S.; Martin, Gary R.

    2009-01-01

    To evaluate the State's water quality, the Kentucky Division of Water collects data from a statewide network of primary ambient stream water-quality monitoring stations and flexible, rotating watershed-monitoring stations. This ambient stream water-quality monitoring network program is directed to assess the conditions of surface waters throughout Kentucky. Water samples were collected monthly for the majority of the stations from 1979 to 1998, which represented agricultural, undeveloped (mainly forested), and areas of mixed land use/land cover. In 1998, the number of water samples collected was reduced to a collection frequency of six times per year (every 2 months) every 4 of 5 years, because a new monitoring network was implemented involving a 5-year rotating Basin Management Unit scheme of monitoring. This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the Kentucky Energy and Environment Cabinet-Kentucky Division of Water, to summarize concentrations of total nitrogen and total phosphorus and provide estimates of total nitrogen and total phosphorus loads and yields in 55 selected streams in Kentucky's ambient stream water-quality monitoring network, which was operated from 1979 through 2004. Streams in predominately agricultural basins had higher concentrations of total nitrogen (TN) and concentrations of total phosphorus (TP) than streams in predominately undeveloped (forested) basins. Streams in basins in intensely developed karst areas characterized by caves, springs, sinkholes, and sinking streams had a higher median concentration of TN (1.5 milligrams per liter [mg/L]) than streams in basins with limited or no karst areas (0.63 mg/L). As with TN, median concentrations of TP also were higher in areas of intense karst (0.05 mg/L) than in areas with limited or no karst (0.02 mg/L). The U.S. Environmental Protection Agency (USEPA) has recommended ecoregional nutrient water-quality criteria as a starting

  6. Subminimal inhibitory concentrations of the disinfectant benzalkonium chloride select for a tolerant subpopulation of Escherichia coli with inheritable characteristics.

    PubMed

    Moen, Birgitte; Rudi, Knut; Bore, Erlend; Langsrud, Solveig

    2012-01-01

    Exposure of Escherichia coli to a subminimal inhibitory concentration (25% below MIC) of benzalkonium chloride (BC), an antimicrobial membrane-active agent commonly used in medical and food-processing environments, resulted in cell death and changes in cell morphology (filamentation). A small subpopulation (1-5% of the initial population) survived and regained similar morphology and growth rate as non-exposed cells. This subpopulation maintained tolerance to BC after serial transfers in medium without BC. To withstand BC during regrowth the cells up regulated a drug efflux associated gene (the acrB gene, member of the AcrAB-TolC efflux system) and changed expression of outer membrane porin genes (ompFW) and several genes involved in protecting the cell from the osmotic- and oxidative stress. Cells pre-exposed to osmotic- and oxidative stress (sodium chloride, salicylic acid and methyl viologen) showed higher tolerance to BC. A control and two selected isolates showing increased BC-tolerance after regrowth in BC was genome sequenced. No common point mutations were found in the BC- isolates but one point mutation in gene rpsA (Ribosomal protein S1) was observed in one of the isolates. The observed tolerance can therefore not solely be explained by the observed point mutation. The results indicate that there are several different mechanisms responsible for the regrowth of a tolerant subpopulation in BC, both BC-specific and general stress responses, and that sub-MIC of BC may select for phenotypic variants in a sensitive E. coli culture.

  7. Computation and use of volume-weighted-average concentrations to determine long-term variations of selected water-quality constituents in lakes and reservoirs

    USGS Publications Warehouse

    Wells, Frank C.; Schertz, Terry L.

    1984-01-01

    A computer program using the Statistical Analysis System has been developed to perform the arithmetic calculations and regression analyses to determine volume-weighted-average concentrations of selected water-quality constituents in lakes and reservoirs. The program has been used in Texas to show decreasing trends in dissolved-solids and total-phosphorus concentrations in Lake Arlington after the discharge of sewage effluent into the reservoir was stopped. The program also was used to show that the August 1978 and October 1981 floods on the Brazos River greatly decreased the volume-weighted-average concentrations of selected constituents in Hubbard Creek Reservoir and Possum Kingdom Lake.

  8. Mercury concentrations in water, and mercury and selenium concentrations in fish from Brownlee Reservoir and selected sites in Boise and Snake Rivers, Idaho and Oregon, 2013

    USGS Publications Warehouse

    MacCoy, Dorene E.

    2014-01-01

    Mercury (Hg) analyses were conducted on samples of sport fish and water collected from six sampling sites in the Boise and Snake Rivers, and Brownlee Reservoir to meet National Pollution Discharge and Elimination System (NPDES) permit requirements for the City of Boise, Idaho. A water sample was collected from each site during October and November 2013 by the City of Boise personnel and was analyzed by the Boise City Public Works Water Quality Laboratory. Total Hg concentrations in unfiltered water samples ranged from 0.73 to 1.21 nanograms per liter (ng/L) at five river sites; total Hg concentration was highest (8.78 ng/L) in a water sample from Brownlee Reservoir. All Hg concentrations in water samples were less than the EPA Hg chronic aquatic life criterion in Idaho (12 ng/L). The EPA recommended a water-quality criterion of 0.30 milligrams per kilogram (mg/kg) methylmercury (MeHg) expressed as a fish-tissue residue value (wet-weight MeHg in fish tissue). MeHg residue in fish tissue is considered to be equivalent to total Hg in fish muscle tissue and is referred to as Hg in this report. The Idaho Department of Environmental Quality adopted the EPA’s fish-tissue criterion and a reasonable potential to exceed (RPTE) threshold 20 percent lower than the criterion or greater than 0.24 mg/kg based on an average concentration of 10 fish from a receiving waterbody. NPDES permitted discharge to waters with fish having Hg concentrations exceeding 0.24 mg/kg are said to have a reasonable potential to exceed the water-quality criterion and thus are subject to additional permit obligations, such as requirements for increased monitoring and the development of a Hg minimization plan. The Idaho Fish Consumption Advisory Program (IFCAP) issues fish advisories to protect general and sensitive populations of fish consumers and has developed an action level of 0.22 mg/kg wet weight Hg in fish tissue. Fish consumption advisories are water body- and species-specific and are used to

  9. Concentration dependence of ionic conductance measured with ion-selective sub-micro pipette probes in aqueous sodium and potassium chloride solutions

    NASA Astrophysics Data System (ADS)

    Son, J. W.; Takami, T.; Lee, J.-K.; Kawai, T.; Park, B. H.

    2011-07-01

    Selective ionic currents in aqueous sodium and potassium chloride solutions with concentrations from 0.01 M to 1.0 M were measured using sub-micro pipette probes in which a poly(vinyl chloride) film containing crown ethers selectively filtered sodium or potassium ions. The selective ionic currents were monitored with a sub-picoampere current measurement system developed from the techniques of TΩ-gap impedance scanning tunneling microscopy. The ionic currents increased with the concentration of the corresponding solution, and thus these sub-micro pipette probes can be applied to detect local ionic concentration of a specific ion in living cells with ionic concentration higher than 0.1 M.

  10. Sensitivity of passive microwave sea ice concentration algorithms to the selection of locally and seasonally adjusted tie points

    NASA Technical Reports Server (NTRS)

    Steffen, Konrad; Schweiger, Axel

    1989-01-01

    The sensitivity of passive microwave sea-ice concentration (SIC) algorithms to the selection of tie points was analyzed. SICs were derived with the NASA Team ice algorithm for global tie points and for locally and seasonally adjusted tie points. The SSM/I SIC was then compared to Landsat-MSS-derived SICs. Preliminary results show a mean difference of SSM/I- and Landsat-derived SICs for 50 x 50 km grid cells of 2.7 percent along the ice edge of the Beaufort Sea during fall with local tie points. The accuracy decreased to 9.7 percent when global tie points were used. During freeze-up in the Beaufort Sea, with grey ice and nilas as dominant ice cover, the mean difference was 4.3 percent for local tie points and 13.9 percent for global tie points. For the spring ice cover in the Bering Sea a mean difference of 4.4 percent for local tie points and 15.7 percent for global tie points was found. This large difference reveals some limitations of the NASA-Team algorithm under freeze-up and spring conditions (thin ice areas).

  11. Methods for estimating concentrations and loads of selected constituents in tributaries to Lake Houston near Houston, Texas

    USGS Publications Warehouse

    Lee, Michael T.

    2012-01-01

    Since December 2005, the U.S. Geological Survey, in cooperation with the City of Houston, Texas, has been assessing the quality of the water flowing into Lake Houston. Continuous in-stream water-quality monitors measured streamflow and other physical water quality properties at stations in Spring Creek near Spring, Tex., and East Fork San Jacinto River near New Caney, Tex. Additionally, discrete water-quality samples were periodically collected on these tributaries and analyzed for selected constituents of concern. Data from the discrete water-quality samples collected during 2005-9, in conjunction with the real-time streamflow data and data from the continuous in-stream water-quality monitors, provided the basis for developing regression equations for the estimation of concentrations of water-quality constituents of these source watersheds to Lake Houston. The output of the regression equations are available through the interactive National Real-Time Water Quality Web site (http://nrtwq.usgs.gov).

  12. Ecological mechanisms of evolution by natural selection: causal processes generating density-and-frequency dependent fitness.

    PubMed

    Nakajima, T

    1998-02-21

    The current theory of natural selection explains that adaptive evolution occurs because genotypes with greater survival or reproductive tendencies, due to their particular biological properties, tend to increase in frequency over the lesser ones in a common environment; therefore, the former will eventually replace the latter. In nature, such a selection process most often occurs in a local population which is nested in a community involving local ecological dynamics which are not clearly articulated in the explanatory scheme of the theory. This paper seeks to explicate such an ecological process giving rise to the evolution of a local population with a particular focus on dynamic effects of an increase in the number of invasive, new types on the fate of old ones. Arguments using the ecological-mechanistic model, representing negative interactions among alternative types of organisms, suggest major ecological mechanisms by which the new replace the old; a selective increase in the number of one type leads to a decrease in the equilibrial abundance of a limiting resource, an increase in the density of conspecifics, and/or an increase in the density of predators, which would in turn lower the per capita reproductive rate, or raise the morality rate of another and make it extinct. Thus, replacement due to selection is associated with such dynamic shifts in equilibria occurring in a local community. The analysis of three (a resource, a prey and a predator) and four species (those plus a top predator) models suggests that evolutionary processes cannot be predicted without reference to the web structure of the community, that some fitness components causing a selective increase in a particular type can have, in some cases, nothing to do with factors causing selective decreases in alternatives, and that evolution of some traits can occur without resource competition.

  13. Selection of targets and ion sources for RIB generation at the Holifield Radioactive Ion Beam Facility

    SciTech Connect

    Alton, G.D.

    1995-12-31

    In this report, the authors describe the performance characteristics for a selected number of target ion sources that will be employed for initial use at the Holifield Radioactive Ion Beam Facility (HRIBF) as well as prototype ion sources that show promise for future use for RIB applications. A brief review of present efforts to select target materials and to design composite target matrix/heat-sink systems that simultaneously incorporate the short diffusion lengths, high permeabilities, and controllable temperatures required to effect fast and efficient diffusion release of the short-lived species is also given.

  14. Spin-Selective Generation of Triplet Nitrenes: Olefin Aziridination through Visible-Light Photosensitization of Azidoformates.

    PubMed

    Scholz, Spencer O; Farney, Elliot P; Kim, Sangyun; Bates, Desiree M; Yoon, Tehshik P

    2016-02-01

    Azidoformates are interesting potential nitrene precursors, but their direct photochemical activation can result in competitive formation of aziridination and allylic amination products. Herein, we show that visible-light-activated transition-metal complexes can be triplet sensitizers that selectively produce aziridines through the spin-selective photogeneration of triplet nitrenes from azidoformates. This approach enables the aziridination of a wide range of alkenes and the formal oxyamination of enol ethers using the alkene as the limiting reagent. Preparative-scale aziridinations can be easily achieved under continuous-flow conditions.

  15. Selective optogenetic activation of arcuate kisspeptin neurons generates pulsatile luteinizing hormone secretion.

    PubMed

    Han, Su Young; McLennan, Timothy; Czieselsky, Katja; Herbison, Allan E

    2015-10-20

    Normal reproductive functioning in mammals depends upon gonadotropin-releasing hormone (GnRH) neurons generating a pulsatile pattern of gonadotropin secretion. The neural mechanism underlying the episodic release of GnRH is not known, although recent studies have suggested that the kisspeptin neurons located in the arcuate nucleus (ARN) may be involved. In the present experiments we expressed channelrhodopsin (ChR2) in the ARN kisspeptin population to test directly whether synchronous activation of these neurons would generate pulsatile luteinizing hormone (LH) secretion in vivo. Characterization studies showed that this strategy targeted ChR2 to 70% of all ARN kisspeptin neurons and that, in vitro, these neurons were activated by 473-nm blue light with high fidelity up to 30 Hz. In vivo, the optogenetic activation of ARN kisspeptin neurons at 10 and 20 Hz evoked high amplitude, pulse-like increments in LH secretion in anesthetized male mice. Stimulation at 10 Hz for 2 min was sufficient to generate repetitive LH pulses. In diestrous female mice, only 20-Hz activation generated significant increments in LH secretion. In ovariectomized mice, 5-, 10-, and 20-Hz activation of ARN kisspeptin neurons were all found to evoke LH pulses. Part of the sex difference, but not the gonadal steroid dependence, resulted from differential pituitary sensitivity to GnRH. Experiments in kisspeptin receptor-null mice, showed that kisspeptin was the critical neuropeptide underlying the ability of ARN kisspeptin neurons to generate LH pulses. Together these data demonstrate that synchronized activation of the ARN kisspeptin neuronal population generates pulses of LH. PMID:26443858

  16. Selective optogenetic activation of arcuate kisspeptin neurons generates pulsatile luteinizing hormone secretion.

    PubMed

    Han, Su Young; McLennan, Timothy; Czieselsky, Katja; Herbison, Allan E

    2015-10-20

    Normal reproductive functioning in mammals depends upon gonadotropin-releasing hormone (GnRH) neurons generating a pulsatile pattern of gonadotropin secretion. The neural mechanism underlying the episodic release of GnRH is not known, although recent studies have suggested that the kisspeptin neurons located in the arcuate nucleus (ARN) may be involved. In the present experiments we expressed channelrhodopsin (ChR2) in the ARN kisspeptin population to test directly whether synchronous activation of these neurons would generate pulsatile luteinizing hormone (LH) secretion in vivo. Characterization studies showed that this strategy targeted ChR2 to 70% of all ARN kisspeptin neurons and that, in vitro, these neurons were activated by 473-nm blue light with high fidelity up to 30 Hz. In vivo, the optogenetic activation of ARN kisspeptin neurons at 10 and 20 Hz evoked high amplitude, pulse-like increments in LH secretion in anesthetized male mice. Stimulation at 10 Hz for 2 min was sufficient to generate repetitive LH pulses. In diestrous female mice, only 20-Hz activation generated significant increments in LH secretion. In ovariectomized mice, 5-, 10-, and 20-Hz activation of ARN kisspeptin neurons were all found to evoke LH pulses. Part of the sex difference, but not the gonadal steroid dependence, resulted from differential pituitary sensitivity to GnRH. Experiments in kisspeptin receptor-null mice, showed that kisspeptin was the critical neuropeptide underlying the ability of ARN kisspeptin neurons to generate LH pulses. Together these data demonstrate that synchronized activation of the ARN kisspeptin neuronal population generates pulses of LH.

  17. Cumulative frequency-dependent selective episodes allow for rapid morph cycles and rock-paper-scissors dynamics in species with overlapping generations

    PubMed Central

    San-Jose, Luis M.; Peñalver-Alcázar, Miguel; Milá, Borja; Gonzalez-Jimena, Virginia; Fitze, Patrick S.

    2014-01-01

    Rock-paper-scissors (RPS) dynamics, which maintain genetic polymorphisms over time through negative frequency-dependent (FD) selection, can evolve in short-lived species with no generational overlap, where they produce rapid morph frequency cycles. However, most species have overlapping generations and thus, rapid RPS dynamics are thought to require stronger FD selection, the existence of which yet needs to be proved. Here, we experimentally demonstrate that two cumulative selective episodes, FD sexual selection reinforced by FD selection on offspring survival, generate sufficiently strong selection to generate rapid morph frequency cycles in the European common lizard Zootoca vivipara, a multi-annual species with major generational overlap. These findings show that the conditions required for the evolution of RPS games are fulfilled by almost all species exhibiting genetic polymorphisms and suggest that RPS games may be responsible for the maintenance of genetic diversity in a wide range of species. PMID:24943372

  18. PHASTpep: Analysis Software for Discovery of Cell-Selective Peptides via Phage Display and Next-Generation Sequencing

    PubMed Central

    Dasa, Siva Sai Krishna; Kelly, Kimberly A.

    2016-01-01

    Next-generation sequencing has enhanced the phage display process, allowing for the quantification of millions of sequences resulting from the biopanning process. In response, many valuable analysis programs focused on specificity and finding targeted motifs or consensus sequences were developed. For targeted drug delivery and molecular imaging, it is also necessary to find peptides that are selective—targeting only the cell type or tissue of interest. We present a new analysis strategy and accompanying software, PHage Analysis for Selective Targeted PEPtides (PHASTpep), which identifies highly specific and selective peptides. Using this process, we discovered and validated, both in vitro and in vivo in mice, two sequences (HTTIPKV and APPIMSV) targeted to pancreatic cancer-associated fibroblasts that escaped identification using previously existing software. Our selectivity analysis makes it possible to discover peptides that target a specific cell type and avoid other cell types, enhancing clinical translatability by circumventing complications with systemic use. PMID:27186887

  19. Beta vulgaris crop types: Genomic signatures of selection (GSS) using next generation sequencing of pooled samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beta vulgaris crop types represent highly diverged populations with distinct phenotypes resulting from long-term selection. Differential end use in the crop types includes: leaf quality (chard/leaf beet), root enlargement and biomass, (table beet, fodder beet, sugar beet), and secondary metabolite a...

  20. Electricity generation and local ion ordering induced by cation-controlled selective anion transportation through graphene oxide membranes

    NASA Astrophysics Data System (ADS)

    Sun, Pengzhan; Deng, Hui; Zheng, Feng; Wang, Kunlin; Zhong, Minlin; Zhang, Yingjiu; Kang, Feiyu; Zhu, Hongwei

    2014-12-01

    A cation-controlled selective anion transportation through graphene oxide (GO) membranes is demonstrated in this work. The results reveal that the trans-membrane transport of different anions can be modulated by the corresponding cations. The diverse interactions among anions, cations, and the negatively charged GO membranes are responsible for selective anion permeation through GO membranes. During the ion penetration, electrical potential differences can be generated across drain and source as well as across GO membranes; based on this, the ion distributions around GO membranes can be determined. The results indicate that local ion ordering can be achieved by GO membranes. Interestingly, for the cases of KNO3, Ca(NO3)2, and Ba(NO3)2, alternate aggregations of metallic cations and NO3- anions can be formed around GO membranes, demonstrating the fantastic ability of these membranes for ordering the ions locally in solutions. In addition, based on the electrical potential differences generated by different salts, chlorides are demonstrated to be ideal sources for efficient practical electricity production compared to sulfates and nitrates, while the different voltage signals generated can be used to identify different source solutions for liquid sensing applications. These results indicate that GO membranes can find potential applications in membrane separation, energy generation, ion recognition, and local ion organizing.

  1. Creativity: The Role of Unconscious Processes in Idea Generation and Idea Selection

    ERIC Educational Resources Information Center

    Ritter, Simone M.; van Baaren, Rick B.; Dijksterhuis, Ap

    2012-01-01

    Today's world of continuous change thrives on creative individuals. Anecdotal reports suggest that creative performance benefits from unconscious processes. Empirical research on the role of the unconscious in creativity, though, is inconsistent and thus far has focused mainly on one aspect of the creative process--idea generation. This is the…

  2. The Self in Action Effects: Selective Attenuation of Self-Generated Sounds

    ERIC Educational Resources Information Center

    Weiss, Carmen; Herwig, Arvid; Schutz-Bosbach, Simone

    2011-01-01

    The immediate experience of self-agency, that is, the experience of generating and controlling our actions, is thought to be a key aspect of selfhood. It has been suggested that this experience is intimately linked to internal motor signals associated with the ongoing actions. These signals should lead to an attenuation of the sensory consequences…

  3. RAD sequencing reveals within-generation polygenic selection in response to anthropogenic organic and metal contamination in North Atlantic Eels.

    PubMed

    Laporte, M; Pavey, S A; Rougeux, C; Pierron, F; Lauzent, M; Budzinski, H; Labadie, P; Geneste, E; Couture, P; Baudrimont, M; Bernatchez, L

    2016-01-01

    Measuring the effects of selection on the genome imposed by human-altered environment is currently a major goal in ecological genomics. Given the polygenic basis of most phenotypic traits, quantitative genetic theory predicts that selection is expected to cause subtle allelic changes among covarying loci rather than pronounced changes at few loci of large effects. The goal of this study was to test for the occurrence of polygenic selection in both North Atlantic eels (European Eel, Anguilla anguilla and American Eel, A. rostrata), using a method that searches for covariation among loci that would discriminate eels from 'control' vs. 'polluted' environments and be associated with specific contaminants acting as putative selective agents. RAD-seq libraries resulted in 23 659 and 14 755 filtered loci for the European and American Eels, respectively. A total of 142 and 141 covarying markers discriminating European and American Eels from 'control' vs. 'polluted' sampling localities were obtained using the Random Forest algorithm. Distance-based redundancy analyses (db-RDAs) were used to assess the relationships between these covarying markers and concentration of 34 contaminants measured for each individual eel. PCB153, 4'4'DDE and selenium were associated with covarying markers for both species, thus pointing to these contaminants as major selective agents in contaminated sites. Gene enrichment analyses suggested that sterol regulation plays an important role in the differential survival of eels in 'polluted' environment. This study illustrates the power of combining methods for detecting signals of polygenic selection and for associating variation of markers with putative selective agents in studies aiming at documenting the dynamics of selection at the genomic level and particularly so in human-altered environments.

  4. A concentration gradient generator on a paper-based microfluidic chip coupled with cell culture microarray for high-throughput drug screening.

    PubMed

    Hong, Bo; Xue, Peng; Wu, Yafeng; Bao, Jingnan; Chuah, Yon Jin; Kang, Yuejun

    2016-02-01

    Inspired by the paper platforms for 3-D cell culture, a paper-based microfluidic device containing drug concentration gradient was designed and constructed for investigating cell response to drugs based on high throughput analysis. This drug gradient generator was applied to generate concentration gradients of doxorubicin (DOX) as the model drug. HeLa cells encapsulated in collagen hydrogel were incubated in the device reservoirs to evaluate the cell viability based on the controlled release of DOX spatially. It was demonstrated that drug diffusion through the paper fibers created a gradient of drug concentration, which influenced cell viability. This drug screening platform has a great opportunity to be applied for drug discovery and diagnostic studies with simultaneous and parallel tests of drugs under various gradient concentrations. PMID:26864970

  5. A concentration gradient generator on a paper-based microfluidic chip coupled with cell culture microarray for high-throughput drug screening.

    PubMed

    Hong, Bo; Xue, Peng; Wu, Yafeng; Bao, Jingnan; Chuah, Yon Jin; Kang, Yuejun

    2016-02-01

    Inspired by the paper platforms for 3-D cell culture, a paper-based microfluidic device containing drug concentration gradient was designed and constructed for investigating cell response to drugs based on high throughput analysis. This drug gradient generator was applied to generate concentration gradients of doxorubicin (DOX) as the model drug. HeLa cells encapsulated in collagen hydrogel were incubated in the device reservoirs to evaluate the cell viability based on the controlled release of DOX spatially. It was demonstrated that drug diffusion through the paper fibers created a gradient of drug concentration, which influenced cell viability. This drug screening platform has a great opportunity to be applied for drug discovery and diagnostic studies with simultaneous and parallel tests of drugs under various gradient concentrations.

  6. Oxidation of diesel-generated volatile organic compounds in the selective catalytic reduction process

    SciTech Connect

    Koebel, M.; Elsener, M.

    1998-10-01

    The main part of the VOCs (volatile organic compounds) contained in diesel exhaust ({approx}80%) is oxidized to CO and CO{sub 2} over an SCR (selective catalytic reduction) catalyst. CO is the major product of this oxidation, representing about 50--70% of the formed products (CO + CO{sub 2}). This preferential formation of CO leads to a pronounced increase of CO emissions when an SCR process is added to a diesel engine. A small fraction of the VOCs is selectively oxidized to carboxylic acids over the SCR catalyst. This selectivity is due to the acidic properties of the catalyst causing the preferential desorption at the oxidation state of the acid. The main products of these oxidation reactions are the lower monocarboxylic acids and some dicarboxylic acids forming stable anhydrides, especially maleic and phthalic acid. The highest emissions of these acids are found at low temperatures; they decrease at higher temperatures. Formic acid is preferentially decomposed into carbon monoxide and water. It must therefore be assumed that the strong increase of CO mentioned above is due to a mechanism involving the thermal decomposition of formic acid formed from various primary VOCs.

  7. Selective vulnerability of late-generated dopaminergic neurons of the substantia nigra in weaver mutant mice.

    PubMed Central

    Bayer, S A; Wills, K V; Triarhou, L C; Verina, T; Thomas, J D; Ghetti, B

    1995-01-01

    In homozygous weaver (wv/wv) mutant mice, nearly 50% of the dopaminergic substantia nigra neurons degenerate by postnatal day 20. We have now determined that the total number of dopaminergic neurons in the ventral midbrains of a litter of obligatory homozygous weaver pups and a litter of normal wild-type control pups indicates that no significant differences are present between groups at birth. To test the hypothesis that the subsequent degeneration of these neurons is linked to their time of origin, [3H]thymidine autoradiography was combined with tyrosine hydroxylase immunocytochemistry to construct neurogenetic timetables on postnatal day 20 in wild-type mice and weaver homozygotes. Both groups have the same span of neurogenesis but have statistically different proportions of neurons generated on specific days. In wild-type mice, more than half of the dopaminergic neurons originate on or after embryonic day 12. In contrast, over two-thirds of the surviving dopaminergic neurons in homozygous weaver mice originate on or before embryonic day 11. Our data suggest that the weaver gene does not interfere with the generation of dopaminergic neurons, but it preferentially kills late-generated dopaminergic neurons between birth and postnatal day 20. Images Fig. 2 PMID:7568088

  8. Sheep deficient in vitamin E preferentially select for a feed with a higher concentration of vitamin E.

    PubMed

    Amanoel, D E; Thomas, D T; Blache, D; Milton, J T B; Wilmot, M G; Revell, D K; Norman, H C

    2016-02-01

    Given the capacity of ruminants to modify diet selection based on metabolic needs, we hypothesised that, when given a choice, lambs experiencing a vitamin E deficiency would consume more of a vitamin E-enriched feed than lambs not deficient in vitamin E. Fifty-six Dohne Merino lambs were divided into two groups and fed either a vitamin E-deficient diet over 40 days to induce low plasma vitamin E or a vitamin E-enriched diet to induce high plasma vitamin E. The lambs were then offered a choice of vitamin E-enriched and vitamin E-deficient pellets. For half of the animals, the enriched diet was paired with strawberry flavour and the deficient diet was paired with orange flavour, while the reverse pairings were offered to the others. Lamb preference for the diets was measured daily for the following 15 days. There was a three-way interaction between the high and low vitamin E treatment groups×vitamin E content and type of flavour in the feed×time (days). The lambs preferred pellets flavoured with strawberry but this preference changed to orange flavour in vitamin E-deficient lambs if the orange flavour was paired with high vitamin E. Lambs without a deficiency continued to prefer strawberry-flavoured pellets, regardless of the vitamin E concentrations in the pellets. It is possible that self-learning contributed to the low vitamin E group of lambs changing preference to orange flavour in order to consume more vitamin E, presumably to remediate the deficiency.

  9. Filtered selection coupled with support vector machines generate a functionally relevant prediction model for colorectal cancer

    PubMed Central

    Gabere, Musa Nur; Hussein, Mohamed Aly; Aziz, Mohammad Azhar

    2016-01-01

    Purpose There has been considerable interest in using whole-genome expression profiles for the classification of colorectal cancer (CRC). The selection of important features is a crucial step before training a classifier. Methods In this study, we built a model that uses support vector machine (SVM) to classify cancer and normal samples using Affymetrix exon microarray data obtained from 90 samples of 48 patients diagnosed with CRC. From the 22,011 genes, we selected the 20, 30, 50, 100, 200, 300, and 500 genes most relevant to CRC using the minimum-redundancy–maximum-relevance (mRMR) technique. With these gene sets, an SVM model was designed using four different kernel types (linear, polynomial, radial basis function [RBF], and sigmoid). Results The best model, which used 30 genes and RBF kernel, outperformed other combinations; it had an accuracy of 84% for both ten fold and leave-one-out cross validations in discriminating the cancer samples from the normal samples. With this 30 genes set from mRMR, six classifiers were trained using random forest (RF), Bayes net (BN), multilayer perceptron (MLP), naïve Bayes (NB), reduced error pruning tree (REPT), and SVM. Two hybrids, mRMR + SVM and mRMR + BN, were the best models when tested on other datasets, and they achieved a prediction accuracy of 95.27% and 91.99%, respectively, compared to other mRMR hybrid models (mRMR + RF, mRMR + NB, mRMR + REPT, and mRMR + MLP). Ingenuity pathway analysis was used to analyze the functions of the 30 genes selected for this model and their potential association with CRC: CDH3, CEACAM7, CLDN1, IL8, IL6R, MMP1, MMP7, and TGFB1 were predicted to be CRC biomarkers. Conclusion This model could be used to further develop a diagnostic tool for predicting CRC based on gene expression data from patient samples. PMID:27330311

  10. Reactibodies generated by kinetic selection couple chemical reactivity with favorable protein dynamics.

    PubMed

    Smirnov, Ivan; Carletti, Eugénie; Kurkova, Inna; Nachon, Florian; Nicolet, Yvain; Mitkevich, Vladimir A; Débat, Hélène; Avalle, Bérangère; Belogurov, Alexey A; Kuznetsov, Nikita; Reshetnyak, Andrey; Masson, Patrick; Tonevitsky, Alexander G; Ponomarenko, Natalia; Makarov, Alexander A; Friboulet, Alain; Tramontano, Alfonso; Gabibov, Alexander

    2011-09-20

    Igs offer a versatile template for combinatorial and rational design approaches to the de novo creation of catalytically active proteins. We have used a covalent capture selection strategy to identify biocatalysts from within a human semisynthetic antibody variable fragment library that uses a nucleophilic mechanism. Specific phosphonylation at a single tyrosine within the variable light-chain framework was confirmed in a recombinant IgG construct. High-resolution crystallographic structures of unmodified and phosphonylated Fabs display a 15-Å-deep two-chamber cavity at the interface of variable light (V(L)) and variable heavy (V(H)) fragments having a nucleophilic tyrosine at the base of the site. The depth and structure of the pocket are atypical of antibodies in general but can be compared qualitatively with the catalytic site of cholinesterases. A structurally disordered heavy chain complementary determining region 3 loop, constituting a wall of the cleft, is stabilized after covalent modification by hydrogen bonding to the phosphonate tropinol moiety. These features and presteady state kinetics analysis indicate that an induced fit mechanism operates in this reaction. Mutations of residues located in this stabilized loop do not interfere with direct contacts to the organophosphate ligand but can interrogate second shell interactions, because the H3 loop has a conformation adjusted for binding. Kinetic and thermodynamic parameters along with computational docking support the active site model, including plasticity and simple catalytic components. Although relatively uncomplicated, this catalytic machinery displays both stereo- and chemical selectivity. The organophosphate pesticide paraoxon is hydrolyzed by covalent catalysis with rate-limiting dephosphorylation. This reactibody is, therefore, a kinetically selected protein template that has enzyme-like catalytic attributes. PMID:21896761

  11. Chiral diaminopyrrolic receptors for selective recognition of mannosides, part 1: design, synthesis, and affinities of second-generation tripodal receptors.

    PubMed

    Nativi, Cristina; Francesconi, Oscar; Gabrielli, Gabriele; Vacca, Alberto; Roelens, Stefano

    2011-04-18

    A new generation of chiral tripodal receptors for recognition of carbohydrates, featuring trans-1,2-diaminocyclohexane as a key structural element, and their recognition properties toward a set of glycosides of biologically relevant monosaccharides is described. The introduction of a chelating diamino unit into the pyrrolic tripodal architecture markedly enhanced their binding abilities compared with the parent aminopyrrolic receptors previously reported by our group. In addition, the chirality of the structure had a clear impact on affinities, as well as on selectivities, displaying high enantiodiscrimination levels. These second-generation diaminopyrrolic tripodal receptors are highly selective for mannose among other monosaccharides, with two members of the family being selective for the α and the β anomers respectively. The measured affinities in acetonitrile, 83 μM of (S)-7 for the β mannoside and 127 μM of (R)-5 for the α mannoside, make them the most effective synthetic receptors for mannosides reported to date. The affinity assessment required a further evolution of the BC(0)(50) parameter, a previously developed binding descriptor, which in its ultimate formulation has now been extended to include, with no restrictions, complexes of any stoichiometry, and can thus be generally employed to rank affinity data from heterogeneous systems on a common scale.

  12. Outer-selective pressure-retarded osmosis hollow fiber membranes from vacuum-assisted interfacial polymerization for osmotic power generation.

    PubMed

    Sun, Shi-Peng; Chung, Tai-Shung

    2013-11-19

    In this paper, we report the technical breakthroughs to synthesize outer-selective thin-film composite (TFC) hollow fiber membranes, which is in an urgent need for osmotic power generation with the pressure-retarded osmosis (PRO) process. In the first step, a defect-free thin-film composite membrane module is achieved by vacuum-assisted interfacial polymerization. The PRO performance is further enhanced by optimizing the support in terms of pore size and mechanical strength and the TFC layer with polydopamine coating and molecular engineering of the interfacial polymerization solution. The newly developed membranes can stand over 20 bar with a peak power density of 7.63 W/m(2), which is equivalent to 13.72 W/m(2) of its inner-selective hollow fiber counterpart with the same module size, packing density, and fiber dimensions. The study may provide insightful guidelines for optimizing the interfacial polymerization procedures and scaling up of the outer-selective TFC hollow fiber membrane modules for PRO power generation.

  13. The selection of convertible engines with current gas generator technology for high speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Eisenberg, Joseph D.

    1990-01-01

    NASA-Lewis has sponsored two studies to determine the most promising convertible engine concepts for high speed rotorcraft. These studies projected year 2000 convertible technology limited to present gas generator technology. Propulsion systems for utilization on aircraft needing thrust only during cruise and those aircraft needing both power and thrust at cruise were investigated. Mission calculations for the two contractors involved were based upon the fold tilt rotor concept. Analysis and comparison of the General Electric concepts (geared UDF, clutched fan, and VIGV fan), and the Allison Gas Turbine concepts (clutched fan, VIGV fan, variable pitch fan, single rotation tractor propfan, and counter rotation tractor propfan) are presented.

  14. The selection of convertible engines with current gas generator technology for high speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Eisenberg, Joseph D.

    1990-01-01

    NASA-Lewis sponsored two studies to determine the most promising convertible engine concepts for high speed rotorcraft. These studies projected year 2000 convertible technology limited to present gas generator technology. Propulsion systems for utilization on aircraft needing thrust only during cruise and those aircraft needing both power and thrust at cruise were investigated. Mission calculations for the two contractors involved were based upon the fold tilt rotor concept. Analysis and comparison of the General Electric concepts (geared UDF, clutched fan, and Variable Inlet Guide Vane (VIGV) fan), and the Allison Gas Turbine concepts (clutched fan, VIGV fan, variable pitch fan, single rotation tractor propfan, and counter rotation tractor propfan) are presented.

  15. Control of combustion-generated nitrogen oxides by selective non-catalytic reduction.

    PubMed

    Javed, M Tayyeb; Irfan, Naseem; Gibbs, B M

    2007-05-01

    Controlling nitrogen oxides (NO(x)) emissions is becoming a daunting technical challenge as increasingly strict emission limits are being imposed. The stringent regulations have prompted the innovation and characterization of NO(x) control technologies suitable for various applications. This paper presents a review on NO(x) removal techniques with particular reference to selective non-catalytic reduction (SNCR) technology. This includes initially how SNCR emerged as a technology along with a comparison with other relevant technologies. A review of various features related to selective non-catalytic gas phase injection of ammonia and ammonium salts (as reducing agent) is presented. The use of urea solution as a reducing agent and its performance in laboratory and pilot scale tests as well as large-scale applications is also discussed. Use of cyanuric acid as a potential reducing agent is also presented. The underlying reaction mechanisms have been reviewed for ammonia, urea and cyanuric acid for the explanation of various observations. Computational fluid dynamics (CFD) modeling as applied to SNCR is also presented. Subsequently the use of SNCR coupled with other in-combustion and post-combustion NO(x) control techniques is elaborated. Additionally, a two-stage NO(x) removal strategy to control un-reacted ammonia slip and to improve overall efficiency is discussed. At the end a summary is given which highlights various areas needing further research.

  16. Tectal microcircuit generating visual selection commands on gaze-controlling neurons

    PubMed Central

    Kardamakis, Andreas A.; Saitoh, Kazuya; Grillner, Sten

    2015-01-01

    The optic tectum (called superior colliculus in mammals) is critical for eye–head gaze shifts as we navigate in the terrain and need to adapt our movements to the visual scene. The neuronal mechanisms underlying the tectal contribution to stimulus selection and gaze reorientation remains, however, unclear at the microcircuit level. To analyze this complex—yet phylogenetically conserved—sensorimotor system, we developed a novel in vitro preparation in the lamprey that maintains the eye and midbrain intact and allows for whole-cell recordings from prelabeled tectal gaze-controlling cells in the deep layer, while visual stimuli are delivered. We found that receptive field activation of these cells provide monosynaptic retinal excitation followed by local GABAergic inhibition (feedforward). The entire remaining retina, on the other hand, elicits only inhibition (surround inhibition). If two stimuli are delivered simultaneously, one inside and one outside the receptive field, the former excitatory response is suppressed. When local inhibition is pharmacologically blocked, the suppression induced by competing stimuli is canceled. We suggest that this rivalry between visual areas across the tectal map is triggered through long-range inhibitory tectal connections. Selection commands conveyed via gaze-controlling neurons in the optic tectum are, thus, formed through synaptic integration of local retinotopic excitation and global tectal inhibition. We anticipate that this mechanism not only exists in lamprey but is also conserved throughout vertebrate evolution. PMID:25825743

  17. Considerations Associated with Reactor Technology Selection for the Next Generation Nuclear Plant Project

    SciTech Connect

    L.E. Demick

    2010-09-01

    At the inception of the Next Generation Nuclear Plant Project and during predecessor activities, alternative reactor technologies have been evaluated to determine the technology that best fulfills the functional and performance requirements of the targeted energy applications and market. Unlike the case of electric power generation where the reactor performance is primarily expressed in terms of economics, the targeted energy applications involve industrial applications that have specific needs in terms of acceptable heat transport fluids and the associated thermodynamic conditions. Hence, to be of interest to these industrial energy applications, the alternative reactor technologies are weighed in terms of the reactor coolant/heat transport fluid, achievable reactor outlet temperature, and practicality of operations to achieve the very high reliability demands associated with the petrochemical, petroleum, metals and related industries. These evaluations have concluded that the high temperature gas-cooled reactor (HTGR) can uniquely provide the required ranges of energy needs for these target applications, do so with promising economics, and can be commercialized with reasonable development risk in the time frames of current industry interest – i.e., within the next 10-15 years.

  18. A next-generation marker genotyping platform (AmpSeq) in heterozygous crops: A case study for marker assisted selection in grapevine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marker assisted selection (MAS) has become widely used in perennial crop breeding programs to accelerate and enhance cultivar development via selection during the juvenile phase and parental selection prior to crossing. Next generation sequencing (NGS) has been widely used for whole genome molecular...

  19. A next-generation marker genotyping platform (AmpSeq) in heterozygous crops: a case study for marker assisted selection in grapevine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marker assisted selection (MAS) is often employed in crop breeding programs to accelerate and enhance cultivar development, via selection during the juvenile phase and parental selection prior to crossing. Next generation sequencing (NGS) and its derivative technologies have been used for genome-wid...

  20. Generating conformation-specific synthetic antibodies to trap proteins in selected functional states

    PubMed Central

    Paduch, Marcin; Koide, Akiko; Uysal, Serdar; Rizk, Shahir S.; Koide, Shohei

    2013-01-01

    A set of phage display sorting strategies and validation methodologies are presented that are capable of producing high performance synthetic antibodies (sABs) with customized properties. Exquisite control of antigen and conditions during the phage display selection process can yield sABs that: 1) recognize conformational states, 2) target specific regions of the surface of a protein, 3) induce conformational changes, and 4) capture and stabilize multiprotein complexes. These unique capabilities open myriad opportunities to study complex macromolecular processes inaccessible to traditional affinity reagent technology. We present detailed protocols for de novo isolation of binders, as well as examples of downstream biophysical characterization. The methods described are generalizable and can be adapted to other in vitro direct evolution approaches based on yeast or mRNA display. PMID:23280336

  1. The Selection of Photons Orbital Angular Momentum Generation Method for FSO

    NASA Astrophysics Data System (ADS)

    Kuzyakov, B. A.; Sivetsky, V. Ya.; Tikhonov, R. V.

    2015-09-01

    The paper deals with methods of the realization of the various states of the orbital angular momentum (OAM) of photons. In a method of phase correction (MPC) a stream of photons with a certain mode of orbital angular momentum is used, in the reception module photons with a corresponding OAM mode are selected, and that allows the telecommunications system correction. A technique using a single-axis crystal, to which an electric voltage is applied, allows to create and highlight a few of the OAM states. The analysis of several methods of the OAM states of photons implementations is made. It is shown that the method of MPC, with using of OAM, has certain advantages.

  2. Guided corona generates wettability patterns that selectively direct cell attachment inside closed microchannels.

    PubMed

    Dixon, Angela; Takayama, Shuichi

    2010-10-01

    We present a method to create plasma mediated linear protein patterns along the lengths of simple one-inlet-one-outlet straight polydimethylsiloxane microchannels by biasing the delivery of corona discharge at the capillary openings. Pattern widths ranging from 500-1,000 microm were generated in 2 mm wide microchannels with lengths of 0.5, 1.0, or 1.5 cm. Corona-treated surfaces enabled the spatial alignment of C2C12 myoblasts to the adhesive protein-coated regions, facilitating myoblast differentiation into myotubes. Although limited in precision, this protein patterning technique offers the advantages of simplicity and low cost, making it attractive for educational and research environments that lack access to extensive microfabrication facilities. The results also provide a cautionary note to those using corona discharge to increase wettability of microchannels; the surface modification may not be uniform, even within single microchannels being treated depending on settings and positioning of the corona device tips.

  3. System and method for generating current by selective minority species heating

    DOEpatents

    Fisch, Nathaniel J.

    1983-01-01

    A system for the generation of toroidal current in a plasma which is prepared in a toroidal magnetic field. The system utilizes the injection of low-frequency waves into the plasma by means of phased antenna arrays or phased waveguide arrays. The plasma is prepared with a minority ion species of different charge state and different gyrofrequency from the majority ion species. The wave frequency and wave phasing are chosen such that the wave energy is absorbed preferentially by minority species ions traveling in one toroidal direction. The absorption of energy in this manner produces a toroidal electric current even when the injected waves themselves do not have substantial toroidal momentum. This current can be continuously maintained at modest cost in power and may be used to confine the plasma. The system can operate efficiently on fusion grade tokamak plasmas.

  4. A program of generation and selection of configurations for the configuration interaction method in atomic calculations SELECTCONF

    NASA Astrophysics Data System (ADS)

    Bogdanovich, P.; Karpuškienė, R.; Momkauskaitė, A.

    2005-11-01

    This program written in FORTRAN is aimed at generation and selection of the admixed configurations which are used in the theoretical calculations of atomic states by the configuration interaction (CI) method. The admixed configurations are generated and selected using the file of radial orbitals written down in the form adopted in the code [C. Froese Fischer, Comput. Phys. Comm. 43 (1987) 355] and other analogous codes. Selection of configurations is performed on the ground of evaluations in the second order of the perturbation theory [P. Bogdanovich, R. Karpu\\vskienė, Comput. Phys. Comm. 134 (2001) 321; R. Karpu\\vskienė, R. Karazija, P. Bogdanovich, Phys. Scripta 64 (2001) 333]. Output of selected configurations is arranged in a format suitable for the codes generating the configuration states [C. Froese Fischer, B. Liu, Comput. Phys. Comm. 64 (1991) 406; P. Bogdanovich, A. Momkauskaitė, Comput. Phys. Comm. 157 (2004) 217]. Program summaryTitle of program:SELECTCONF Catalogue identifier:ADWD Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWD Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:None Computers:Any computer with a FORTRAN 77 compiler Operating systems under which the program has been tested:Linux Programming language used:FORTRAN 77 Memory required to execute with typical data:4 MB No. of lines in distributed program, including test data, etc.:7459 No. of bytes in distributed program, including test data, etc.:108 420 Distribution format:gzip file Nature of the physical problem:Due to the restricted possibilities of the computers and codes, which are employed, the practice of CI requires one to select and superpose those configurations the usage of which happens to be the most effective. This program is designed for the selection of such admixed configurations. Method of solution:All admixed configurations possible in the specified basis set of radial orbitals (RO) are constructed

  5. Effect of hydrogen generated by dielectric barrier discharge of NH3 on selective non-catalytic reduction process.

    PubMed

    Byun, Youngchul; Ko, Kyung Bo; Cho, Moohyun; Namkung, Won; Shin, Dong Nam; Koh, Dong Jun

    2009-05-01

    Plasma-assisted selective non-catalytic reduction (SNCR) has been investigated to clarify which species generated by the plasma play a crucial role in NO reduction. We find that the presence of O(2) is indispensable and only H(2) is observed to be a stable product by dielectric barrier discharge (DBD) of NH(3). As the extent of NH(3) decomposition by DBD increases, the commencement temperature of SNCR processes is lowered and the working temperature window is widened. This propensity may be attributed to the chemical reaction of H(2) with O(2) to generate OH and H radicals which make it possible to yield NH(2) radicals even at low temperature.

  6. Tritium concentrations in flow from selected springs that discharge to the Snake River, Twin Falls-Hagerman area, Idaho

    USGS Publications Warehouse

    Mann, L.J.

    1989-01-01

    Concern has been expressed that some of the approximately 30,900 curies of tritium disposed to the Snake River Plain aquifer from 1952 to 1988 at the INEL (Idaho National Engineering Laboratory) have migrated to springs discharging to the Snake River in the Twin Falls-Hagerman area. To document tritium concentrations in springflow, 17 springs were sampled in November 1988 and 19 springs were sampled in March 1989. Tritium concentrations were less than the minimum detectable concentration of 0.5 pCi/mL (picocuries/mL) in November 1988 and less than the minimum detectable concentration of 0.2 pCi/mL in March 1989; the minimum detectable concentration was smaller in March 1989 owing to a longer counting time in the liquid scintillation system. The maximum contaminant level of tritium in drinking water as established by the U.S. Environmental Protection Agency is 20 pCi/mL. U.S. Environmental Protection Agency sample analyses indicate that the tritium concentration has decreased in the Snake River near Buhl since the 1970's. In 1974-79, tritium concentrations were less than 0.3 +/-0.2 pCi/mL in 3 of 20 samples; in 1983-88, 17 of 23 samples contained less than 0.3 +/-0.2 pCi/mL of tritium; the minimum detectable concentration is 0.2 pCi/mL. On the basis of decreasing tritium concentrations in the Snake River, their correlation to cessation of atmospheric weapons tests tritium concentrations in springflow less than the minimum detectable concentration, and the distribution of tritium in groundwater at the INEL, aqueous disposal of tritium at the INEL has had no measurable effect on tritium concentrations in springflow from the Snake River Plain aquifer and in the Snake River near Buhl. (USGS)

  7. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  8. Factors influencing storm-generated suspended-sediment concentrations and loads in four basins of contrasting land use, humid-tropical Puerto Rico

    USGS Publications Warehouse

    Gellis, Allen C.

    2013-01-01

    The significant characteristics controlling the variability in storm-generated suspended-sediment loads and concentrations were analyzed for four basins of differing land use (forest, pasture, cropland, and urbanizing) in humid-tropical Puerto Rico. Statistical analysis involved stepwise regression on factor scores. The explanatory variables were attributes of flow, hydrograph peaks, and rainfall, categorized into 5 flow periods: (1) the current storm hydrograph, (2) the flow and rainfall since the previous storm event, (3) the previous storm event, (4) 2nd previous storm event, and (5) the 3rd previous storm event. The response variables (storm generated sediment loads and concentrations) were analyzed for three portions of the storm hydrograph: (1) the entire storm, (2) the rising limb, and (3) the recessional limb. Hysteresis differences in sediment concentration between the rising and falling limb were also analyzed using these explanatory variables.

  9. Report to Congress on Assessment of Potential Impact of Concentrating Solar Power for Electriicty Generation (EPACT 2005--Section 934(c))

    SciTech Connect

    Wilkins, F.

    2007-02-01

    Summary of DOE's assessment of issues regarding EPAct 2005, which requires the Secretary of Energy to assess conflicting guidance on the economic potential of concentrating solar power for electricity production.

  10. Subset selection of high-depth next generation sequencing reads for de novo genome assembly using MapReduce framework

    PubMed Central

    2015-01-01

    Background Recent progress in next-generation sequencing technology has afforded several improvements such as ultra-high throughput at low cost, very high read quality, and substantially increased sequencing depth. State-of-the-art high-throughput sequencers, such as the Illumina MiSeq system, can generate ~15 Gbp sequencing data per run, with >80% bases above Q30 and a sequencing depth of up to several 1000x for small genomes. Illumina HiSeq 2500 is capable of generating up to 1 Tbp per run, with >80% bases above Q30 and often >100x sequencing depth for large genomes. To speed up otherwise time-consuming genome assembly and/or to obtain a skeleton of the assembly quickly for scaffolding or progressive assembly, methods for noise removal and reduction of redundancy in the original data, with almost equal or better assembly results, are worth studying. Results We developed two subset selection methods for single-end reads and a method for paired-end reads based on base quality scores and other read analytic tools using the MapReduce framework. We proposed two strategies to select reads: MinimalQ and ProductQ. MinimalQ selects reads with minimal base-quality above a threshold. ProductQ selects reads with probability of no incorrect base above a threshold. In the single-end experiments, we used Escherichia coli and Bacillus cereus datasets of MiSeq, Velvet assembler for genome assembly, and GAGE benchmark tools for result evaluation. In the paired-end experiments, we used the giant grouper (Epinephelus lanceolatus) dataset of HiSeq, ALLPATHS-LG genome assembler, and QUAST quality assessment tool for comparing genome assemblies of the original set and the subset. The results show that subset selection not only can speed up the genome assembly but also can produce substantially longer scaffolds. Availability: The software is freely available at https://github.com/moneycat/QReadSelector. PMID:26678408

  11. Optimization design of hybrid Fresnel-based concentrator for generating uniformity irradiance with the broad solar spectrum

    NASA Astrophysics Data System (ADS)

    Zhuang, Zhenfeng; Yu, Feihong

    2014-08-01

    This paper presents a novel hybrid Fresnel-based concentrator with improved uniformity irradiance distribution on the solar cell without using secondary optical element (SOE) in the concentrator photovoltaic (CPV) system to overcome the Fresnel loss and to increase the solar cell conversion efficiency. The designed hybrid Fresnel-based concentrator is composed of two parts, the inner part and the outer part. The inner part is the conventional Fresnel lens, while the outer part is double total internal reflection (DTIR) lens. According to the simple geometrical relation, the profile of the proposed hybrid Fresnel-based concentrator is calculated as an initial design profile. To obtain good irradiance uniformity on the solar cell, optimal prism displacements are optimized by using a simplex algorithm for collimated incident sunlight based on different prism focus on different position principles. In addition, a Monte-Carlo ray-tracing simulation approach is utilized to verify the optical performance for the hybrid Fresnel-based concentrator. Results indicate that the hybrid Fresnel-based concentrator designed using this method can achieve spatial non-uniformity less than 16.2%, f-number less than 0.59 (focal length to entry aperture diameter ratio), geometrical concentrator ratio 1759.8×, and acceptance angle ±0.23°. Compared to the conventional Fresnel-based lens and the traditional hybrid Fresnel-based lens, the optimized concentrator yields a significant improvement in irradiance uniformity on the solar cell with a wide solar spectrum range. It also has good tolerance to the incident sunlight.

  12. Serotonin selectively enhances perception and sensory neural responses to stimuli generated by same-sex conspecifics

    PubMed Central

    Deemyad, Tara; Metzen, Michael G.; Pan, Yingzhou; Chacron, Maurice J.

    2013-01-01

    Centrifugal serotonergic fibers innervating sensory brain areas are seen ubiquitously across systems and species but their function remains unclear. Here we examined the functional role of serotonergic innervation onto electrosensory neurons in weakly electric fish by eliciting endogenous release through electrical stimulation as well as exogenous focal application of serotonin in the vicinity of the cell being recorded from. Both approaches showed that the function of serotonergic input onto electrosensory pyramidal neurons is to render them more excitable by reducing the spike afterhyperpolarization amplitude and thereby promoting burst firing. Further, serotonergic input selectively improved neuronal responses to stimuli that occur during interactions between same-sex conspecifics but not to stimuli associated with either prey or that occur during interactions between opposite-sex conspecifics. Finally, we tested whether serotonin-mediated enhanced pyramidal neuron responses to stimuli associated with same-sex conspecifics actually increase perception by the animal. Our behavioral experiments show that exogenous injection and endogenous release of serotonin both increase the magnitude of behavioral responses to stimuli associated with same-sex conspecifics as well as simultaneously decrease aggressive behaviors. Thus, our data indicate that the serotonergic system inhibits aggressive behavior toward same-sex conspecifics, while at the same time increasing perception of stimuli associated with these individuals. This function is likely to be conserved across systems and species. PMID:24218585

  13. Selective ablation of thin films in latest generation CIGS solar cells with picosecond pulses

    NASA Astrophysics Data System (ADS)

    Burn, Andreas; Romano, Valerio; Muralt, Martin; Witte, Reiner; Frei, Bruno; Bücheler, Stephan; Nishiwaki, Shiro

    2012-03-01

    Recent developments in Cu(In,Ga)Se2 (CIGS) thin film photovoltaics enabled the manufacturers to produce highly efficient solar modules. Nevertheless, the production process still lacks a competitive process for module patterning. Today, the industry standard for the serial interconnection of cells is still based on mechanical scribing for the P2 and P3 process. A reduction of the non-productive "dead zone" between the P1 and P3 scribes is crucial for further increasing module efficiency. Compact and affordable picosecond pulsed laser sources are promising tools towards all-laser scribing of CIGS solar modules. We conducted an extensive parameter study comprising picosecond laser sources from 355 to 1064 nm wavelength and 10 to 50 ps pulse duration. Scribing results were analyzed by laser scanning microscope, scanning electron microscope and energy dispersive X-ray spectroscopy. We developed stable and reliable processes for the P1, P2 and P3 scribe. The best parameter sets were then used for the production of functional mini-modules. For comparison, the same was done for a selection of nanosecond pulsed lasers. Standardized analysis of the modules has shown superior electrical performance of the interconnections and confirmed the feasibility of a dead zone width of less than 200 ìm on an entire mini module.

  14. Site Selection & Characterization Status Report for Next Generation Nuclear Plant (NGNP)

    SciTech Connect

    Mark Holbrook

    2007-09-01

    In the near future, the US Department of Energy (DOE) will need to make important decisions regarding design and construction of the Next Generation Nuclear Plant (NGNP). One part of making these decisions is considering the potential environmental impacts that this facility may have, if constructed here at the Idaho National Laboratory (INL). The National Environmental Policy Act (NEPA) of 1969 provides DOE decision makers with a process to systematically consider potential environmental consequences of agency decisions. In addition, the Energy Policy Act of 2005 (Title VI, Subtitel C, Section 644) states that the 'Nuclear Regulatory Commission (NRC) shall have licensing and regulatory authority for any reactor authorized under this subtitle.' This stipulates that the NRC will license the NGNP for operation. The NRC NEPA Regulations (10 CFR Part 51) require tha thte NRC prepare an Environmental Impact Statement (EIS) for a permit to construct a nuclear power plant. The applicant is required to submit an Environmental report (ER) to aid the NRC in complying with NEPA.

  15. Gene expression changes in the coccolithophore Emiliania huxleyi after 500 generations of selection to ocean acidification.

    PubMed

    Lohbeck, Kai T; Riebesell, Ulf; Reusch, Thorsten B H

    2014-07-01

    Coccolithophores are unicellular marine algae that produce biogenic calcite scales and substantially contribute to marine primary production and carbon export to the deep ocean. Ongoing ocean acidification particularly impairs calcifying organisms, mostly resulting in decreased growth and calcification. Recent studies revealed that the immediate physiological response in the coccolithophore Emiliania huxleyi to ocean acidification may be partially compensated by evolutionary adaptation, yet the underlying molecular mechanisms are currently unknown. Here, we report on the expression levels of 10 candidate genes putatively relevant to pH regulation, carbon transport, calcification and photosynthesis in E. huxleyi populations short-term exposed to ocean acidification conditions after acclimation (physiological response) and after 500 generations of high CO2 adaptation (adaptive response). The physiological response revealed downregulation of candidate genes, well reflecting the concomitant decrease of growth and calcification. In the adaptive response, putative pH regulation and carbon transport genes were up-regulated, matching partial restoration of growth and calcification in high CO2-adapted populations. Adaptation to ocean acidification in E. huxleyi likely involved improved cellular pH regulation, presumably indirectly affecting calcification. Adaptive evolution may thus have the potential to partially restore cellular pH regulatory capacity and thereby mitigate adverse effects of ocean acidification.

  16. Gene expression changes in the coccolithophore Emiliania huxleyi after 500 generations of selection to ocean acidification

    PubMed Central

    Lohbeck, Kai T.; Riebesell, Ulf; Reusch, Thorsten B. H.

    2014-01-01

    Coccolithophores are unicellular marine algae that produce biogenic calcite scales and substantially contribute to marine primary production and carbon export to the deep ocean. Ongoing ocean acidification particularly impairs calcifying organisms, mostly resulting in decreased growth and calcification. Recent studies revealed that the immediate physiological response in the coccolithophore Emiliania huxleyi to ocean acidification may be partially compensated by evolutionary adaptation, yet the underlying molecular mechanisms are currently unknown. Here, we report on the expression levels of 10 candidate genes putatively relevant to pH regulation, carbon transport, calcification and photosynthesis in E. huxleyi populations short-term exposed to ocean acidification conditions after acclimation (physiological response) and after 500 generations of high CO2 adaptation (adaptive response). The physiological response revealed downregulation of candidate genes, well reflecting the concomitant decrease of growth and calcification. In the adaptive response, putative pH regulation and carbon transport genes were up-regulated, matching partial restoration of growth and calcification in high CO2-adapted populations. Adaptation to ocean acidification in E. huxleyi likely involved improved cellular pH regulation, presumably indirectly affecting calcification. Adaptive evolution may thus have the potential to partially restore cellular pH regulatory capacity and thereby mitigate adverse effects of ocean acidification. PMID:24827439

  17. [Improvement of sensitivity in the second generation HCV core antigen assay by a novel concentration method using polyethylene glycol (PEG)].

    PubMed

    Higashimoto, Makiko; Takahashi, Masahiko; Jokyu, Ritsuko; Syundou, Hiromi; Saito, Hidetsugu

    2007-11-01

    A HCV core antigen (Ag) detection assay system, Lumipulse Ortho HCV Ag has been developed and is commercially available in Japan with a lower detection level limit of 50 fmol/l, which is equivalent to 20 KIU/ml in PCR quantitative assay. HCV core Ag assay has an advantage of broader dynamic range compared with PCR assay, however the sensitivity is lower than PCR. We developed a novel HCV core Ag concentration method using polyethylene glycol (PEG), which can improve the sensitivity five times better than the original assay. The reproducibility was examined by consecutive five-time measurement of HCV patients serum, in which the results of HCV core Ag original and concentrated method were 56.8 +/- 8.1 fmol/l (mean +/- SD), CV 14.2% and 322.9 +/- 45.5 fmol/l CV 14.0%, respectively. The assay results of HCV negative samples in original HCV core Ag were all 0.1 fmol/l and the results were same even in the concentration method. The results of concentration method were 5.7 times higher than original assay, which was almost equal to theoretical rate as expected. The assay results of serially diluted samples were also as same as expected data in both original and concentration assay. We confirmed that the sensitivity of HCV core Ag concentration method had almost as same sensitivity as PCR high range assay in the competitive assay study using the serially monitored samples of five HCV patients during interferon therapy. A novel concentration method using PEG in HCV core Ag assay system seems to be useful for assessing and monitoring interferon treatment for HCV.

  18. First-generation Hispanic freshmen perceptions of selecting a STEM major

    NASA Astrophysics Data System (ADS)

    Carrandi Molina, Elizabeth

    The purpose of this study was to explore the perceptions of Hispanic first-generation college students (FGCSs) who made the immediate transition from high school into a science, technology, engineering, or mathematics (STEM) field of study at a public, four-year higher education institution in South Florida. The conceptual foundation for this study was Bourdieu's (1986) Theory of Cultural Capital and Bandura's (1977) Theory of Self-Efficacy. Ten purposefully sampled participants engaged in face-to-face interviews or Skye/FaceTime with a total maximum duration of 90 minutes including member checking. As a result of the data collection and analysis, a total of six themes emerged: lack of cultural capital transmitted by cultural activities, high levels of parental encouragement/involvement, high levels of cultural capital transmitted through formal schooling, high levels of self-efficacy, beliefs of personal success, and overcoming challenges. Theme one evoked two subthemes: challenges and family life. Theme two produced two subthemes: home culture and cultural values. Theme three formed two subthemes: course rigor and teacher-student communication/relationships. Theme four conjured three subthemes: mindset, vicarious experiences, and home discourse. Theme five yielded two subthemes: verbal persuasion and performance accomplishments/mastery experiences. Finally, theme six formed one subtheme: biases. Findings from this study may benefit the literature on the lack of representation of Hispanic FGCSs in STEM fields in higher education and may serve as a starting point for the conception of programs and initiatives to spark and sustain student interest in STEM, and ultimately influence a student's decision to pursue a STEM degree in higher education.

  19. Trace-metal concentrations, waters from selected sky lakes, streams and springs, northern Shawangunk Mountains, New York: geologic and ecologic implications

    USGS Publications Warehouse

    Friedman, J.D.; Huth, P.C.; Smiley, D.

    1990-01-01

    Reconnaissance sampling and chemical analysis of water from selected lakes, streams and springs of the northern Shawangunk Mountains in 1987 to 1988 to determine the influence of lithology on trace-metal concentrations in surface water, and to establish a base level of concentration of 27 selected metals by ICP-AES and Hg by cold-vapor AAS methods, for geochemical exploration, ecologic, acid-rain, and climatic-change studies, have yielded trace-metal concentrations greater than detection limits for 10 metallic elements. Eighteen additional metallic elements were also present in trace quantities below the quantitative detection limit. Two distinct geochemical populations are related to source lithology and pH. -from Authors

  20. Relationships between concentrations of selected organohalogen contaminants and thyroid hormones and vitamins A, E and D in Faroese pilot whales.

    PubMed

    Hoydal, Katrin S; Ciesielski, Tomasz M; Borrell, Asunción; Wasik, Andrzej; Letcher, Robert J; Dam, Maria; Jenssen, Bjørn M

    2016-07-01

    Pilot whales (Globicephala melas) from the Faroe Islands, North-East Atlantic, have high body concentrations of organohalogenated compounds (OHCs), such as polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs) and brominated flame retardants (BFRs). The aim of the present study was to examine if and to what extent blood plasma and liver concentrations of several groups of these OHCs are related to concentrations of relevant nutritional and hormonal biomarkers in pilot whales. Thyroid hormones (THs: total and free thyroxine and total and free triiodothyronine) and vitamin A (retinol), D (25-hydroxyvitamin D3) and E (α-tocopherol) were analysed in plasma (n=27) and vitamin A (total vitamin A, retinol and retinyl palmitate) and E (α- and γ-tocopherol) were analysed in liver (n=37) of Faroe Island pilot whales. Correlative relationships between the biomarkers and OHC concentrations previously analysed in the same tissues in these individuals were studied. The TH concentrations in plasma were significantly higher in juveniles than in adults. Vitamin D concentrations in plasma and α- and γ-tocopherol in liver were higher in adults than in juveniles. Multivariate statistical modelling showed that the age and sex influenced the relationship between biomarkers and OHCs. Some significant positive relationships were found between OHCs and thyroid hormone concentrations in the youngest juveniles (p<0.05). In plasma of juvenile whales α-tocopherol was also positively correlated with all the OHCs (p<0.05). Only few significant correlations were found between single OHCs and retinol and vitamin D in plasma within the age groups. There were significant negative relationships between hepatic PBDE concentrations and retinol (BDE-47) and γ-tocopherol (BDE-49, -47, -100, -99, -153) in liver. The relationships between OHCs and THs or vitamins suggest that in pilot whales OHCs seem to have minor effects on TH and vitamin concentrations.

  1. Concentration and spatial distribution of selected constituents in Detroit River bed sediment adjacent to Grassy Island, Michigan, August 2006

    USGS Publications Warehouse

    Hoard, C.J.

    2008-01-01

    In August 2006, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, collected sediment?core samples from the bed of the Detroit River adjacent to Grassy Island. The goal of the sampling was to assess the distribution and concentration of chemical constituents in sediment adjacent to Grassy Island, which was operated from 1960 to 1982 as a confined disposal facility to hold dredge spoils. On August 31, 2006, seven samples were collected at four locations in the Detroit River on the north, south, east, and west sides of the island. Metals concentrations in the riverbed sediment tended to be higher on the west side of the island, whereas organic?compound concentrations were generally higher on the east side. Comparison of results from this sampling to concentrations reported in previous studies indicates that the concentrations of inorganic constituents, mainly metals, in the riverbed sediment around Grassy Island fell within the range of concentrations found regionally throughout the Detroit River and in most cases have lower mean and median values than found elsewhere regionally in the Detroit River. Comparison of results from the August 31, 2006, sampling to U.S. Environmental Protection Agency risk?based sediment?quality guidelines indicates that 18 organic constituents for which an ecological screening level (ESL), and (or) a threshold effect concentration (TEC), and (or) a probable effect concentration (PEC) has been defined exceeded one or more of these guidelines at least once. Further work would be needed to determine whether constituent concentrations in the river sediment are related to constituent runoff from Grassy Island.

  2. Concentration and Spatial Distribution of Selected Constituents in Detroit River Bed Sediment Adjacent to Grassy Island, Michigan, August 2006

    USGS Publications Warehouse

    Hoard, C.J.

    2008-01-01

    In August 2006, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, collected sediment?core samples from the bed of the Detroit River adjacent to Grassy Island. The goal of the sampling was to assess the distribution and concentration of chemical constituents in sediment adjacent to Grassy Island, which was operated from 1960 to 1982 as a confined disposal facility to hold dredge spoils. On August 31, 2006, seven samples were collected at four locations in the Detroit River on the north, south, east, and west sides of the island. Metals concentrations in the riverbed sediment tended to be higher on the west side of the island, whereas organic?compound concentrations were generally higher on the east side. Comparison of results from this sampling to concentrations reported in previous studies indicates that the concentrations of inorganic constituents, mainly metals, in the riverbed sediment around Grassy Island fell within the range of concentrations found regionally throughout the Detroit River and in most cases have lower mean and median values than found elsewhere regionally in the Detroit River. Comparison of results from the August 31, 2006, sampling to U.S. Environmental Protection Agency risk?based sediment?quality guidelines indicates that 18 organic constituents for which an ecological screening level (ESL), and (or) a threshold effect concentration (TEC), and (or) a probable effect concentration (PEC) has been defined exceeded one or more of these guidelines at least once. Further work would be needed to determine whether constituent concentrations in the river sediment are related to constituent runoff from Grassy Island.

  3. Relationships between concentrations of selected organohalogen contaminants and thyroid hormones and vitamins A, E and D in Faroese pilot whales.

    PubMed

    Hoydal, Katrin S; Ciesielski, Tomasz M; Borrell, Asunción; Wasik, Andrzej; Letcher, Robert J; Dam, Maria; Jenssen, Bjørn M

    2016-07-01

    Pilot whales (Globicephala melas) from the Faroe Islands, North-East Atlantic, have high body concentrations of organohalogenated compounds (OHCs), such as polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs) and brominated flame retardants (BFRs). The aim of the present study was to examine if and to what extent blood plasma and liver concentrations of several groups of these OHCs are related to concentrations of relevant nutritional and hormonal biomarkers in pilot whales. Thyroid hormones (THs: total and free thyroxine and total and free triiodothyronine) and vitamin A (retinol), D (25-hydroxyvitamin D3) and E (α-tocopherol) were analysed in plasma (n=27) and vitamin A (total vitamin A, retinol and retinyl palmitate) and E (α- and γ-tocopherol) were analysed in liver (n=37) of Faroe Island pilot whales. Correlative relationships between the biomarkers and OHC concentrations previously analysed in the same tissues in these individuals were studied. The TH concentrations in plasma were significantly higher in juveniles than in adults. Vitamin D concentrations in plasma and α- and γ-tocopherol in liver were higher in adults than in juveniles. Multivariate statistical modelling showed that the age and sex influenced the relationship between biomarkers and OHCs. Some significant positive relationships were found between OHCs and thyroid hormone concentrations in the youngest juveniles (p<0.05). In plasma of juvenile whales α-tocopherol was also positively correlated with all the OHCs (p<0.05). Only few significant correlations were found between single OHCs and retinol and vitamin D in plasma within the age groups. There were significant negative relationships between hepatic PBDE concentrations and retinol (BDE-47) and γ-tocopherol (BDE-49, -47, -100, -99, -153) in liver. The relationships between OHCs and THs or vitamins suggest that in pilot whales OHCs seem to have minor effects on TH and vitamin concentrations. PMID:27131793

  4. Optimization of bioelectricity generation in fed-batch microbial fuel cell: effect of electrode material, initial substrate concentration, and cycle time.

    PubMed

    Cirik, Kevser

    2014-05-01

    Effective wastewater treatment and electricity generation using dual-chamber microbial fuel cell (MFC) will require a better understanding of how operational parameters affect system performance. Therefore, the main aim of this study is to investigate the bioelectricity production in a dual-chambered MFC-operated batch mode under different operational conditions. Initially, platinum (Pt) and mixed metal oxide titanium (Ti-TiO2) electrodes were used to investigate the influence of the electrode materials on the power generation at initial dissolved organic carbon (DOC) concentration of 400 mg/L and cycle time of 15 days. MFC equipped with Ti-TiO2 electrode performed better and was used to examine the effect of influent DOC concentration and cycle time on MFC performance. Increasing influent DOC concentration resulted in improving electricity generation, corresponding to a 1.65-fold increase in power density. However, decrease in cycle time from 15 to 5 days adversely affected reactor performance. Maximum DOC removal was 90 ± 3 %, which was produced at 15-day cycle time with an initial DOC of 3,600 mg/L, corresponding to maximum power generation of about 7,205 mW/m(2). PMID:24639089

  5. Retrospective study testing next generation sequencing of selected cancer-associated genes in resected prostate cancer

    PubMed Central

    Bollito, Enrico; Garrou, Diletta; Cappia, Susanna; Rapa, Ida; Vignani, Francesca; Bertaglia, Valentina; Fiori, Cristian; Papotti, Mauro; Volante, Marco; Scagliotti, Giorgio V.; Porpiglia, Francesco; Tucci, Marcello

    2016-01-01

    Purpose Prostate cancer (PCa) has a highly heterogeneous outcome. Beyond Gleason Score, Prostate Serum Antigen and tumor stage, nowadays there are no biological prognostic factors to discriminate between indolent and aggressive tumors. The most common known genomic alterations are the TMPRSS-ETS translocation and mutations in the PI3K, MAPK pathways and in p53, RB and c-MYC genes. The aim of this retrospective study was to identify by next generation sequencing the most frequent genetic variations (GVs) in localized and locally advanced PCa underwent prostatectomy and to investigate their correlation with clinical-pathological variables and disease progression. Results Identified non-synonymous GVs included TP53 p.P72R (78% of tumors), two CSFR1 SNPs, rs2066934 and rs2066933 (70%), KDR p.Q472H (67%), KIT p.M541L (28%), PIK3CA p.I391M (19%), MET p.V378I (10%) and FGFR3 p.F384L/p.F386L (8%). TP53 p.P72R, MET p.V378I and CSFR1 SNPs were significantly associated with the HI risk group, TP53 and MET variations with T≥T2c. FGFR3 p.F384L/p.F386L was correlated with T≤T2b. MET p.V378I mutation, detected in 20% of HI risk patients, was associated with early biochemical recurrence. Experimental design Nucleic acids were obtained from tissue samples of 30 high (HI) and 30 low-intermediate (LM) risk patients, according to D'Amico criteria. Genomic DNA was explored with the Ion_AmpliSeq_Cancer_Hotspot_Panel_v.2 including 50 cancer-associated genes. GVs with allelic frequency (AF) ≥10%, affecting protein function or previously associated with cancer, were correlated with clinical-pathological variables. Conclusion Our results confirm a complex mutational profile in PCa, supporting the involvement of TP53, MET, FGFR3, CSF1R GVs in tumor progression and aggressiveness. PMID:26887047

  6. Pregnancy Outcome in a Multi-Generational Rat Bioassay of Drinking Water Concentrates in the Four Lab Study

    EPA Science Inventory

    To address concerns raised by epidemiological studies, we conducted a multigenerational reproductive toxicity study in rats using a “whole” mixture of drinking water disinfection by-products (DBPs). Raw water was concentrated ~130 fold, chlorinated, and provided as drinking water...

  7. Reproductive Development in a Multi-Generational Rat Bioassay of Drinking Water Concentrates in the Four Lab Study

    EPA Science Inventory

    To address concerns raised by epidemiological studies, we conducted a multigenerational reproductive toxicity study in rats using a “whole” mixture of drinking water disinfection by-products (DBPs). Raw water was concentrated ~130 fold, chlorinated, and provided as drinking wate...

  8. Results of testing a development module of the second-generation E-Systems concentrating photovoltaic-thermal module

    SciTech Connect

    Harrison, T D

    1982-04-01

    An actively-cooled linear Fresnel lens concentrating photovoltaic and thermal module, designed and built by E-Systems, was tested in the Photovoltaic Advanced Systems Test Facility. Physical, electrical, and thermal characteristics of the module are presented. Module performance is characterized through the use of multiple linear regression techniques.

  9. HLYWD: a program for post-processing data files to generate selected plots or time-lapse graphics

    SciTech Connect

    Munro, J.K. Jr.

    1980-05-01

    The program HLYWD is a post-processor of output files generated by large plasma simulation computations or of data files containing a time sequence of plasma diagnostics. It is intended to be used in a production mode for either type of application; i.e., it allows one to generate along with the graphics sequence, segments containing title, credits to those who performed the work, text to describe the graphics, and acknowledgement of funding agency. The current version is designed to generate 3D plots and allows one to select type of display (linear or semi-log scales), choice of normalization of function values for display purposes, viewing perspective, and an option to allow continuous rotations of surfaces. This program was developed with the intention of being relatively easy to use, reasonably flexible, and requiring a minimum investment of the user's time. It uses the TV80 library of graphics software and ORDERLIB system software on the CDC 7600 at the National Magnetic Fusion Energy Computing Center at Lawrence Livermore Laboratory in California.

  10. A model for selecting bioindicators to monitor radionuclide concentrations using Amchitka Island in the Aleutians as a case study.

    PubMed

    Burger, Joanna

    2007-11-01

    World War II and the Cold War have left the Unites States, and other Nations, with massive cleanup and remediation tasks for radioactive and other legacy hazardous wastes. While some sites can be cleaned up to acceptable residential risk levels, others will continue to hold hazardous wastes, which must be contained and monitored to protect human health and the environment. While media (soil, sediment, groundwater) monitoring is the usual norm at many radiological waste sites, for some situations (both biological and societal), biomonitoring may provide the necessary information to assure greater peace of mind for local and regional residents, and to protect ecologically valuable buffer lands or waters. In most cases, indicators are selected using scientific expertise and a literature review, but not all selected indicators will seem relevant to stakeholders. In this paper, I provide a model for the inclusion of stakeholders in the development of bioindicators for assessing radionuclide levels of biota in the marine environment around Amchitka Island, in the Aleutian Chain of Alaska. Amchitka was the site of three underground nuclear tests from 1965 to 1971. The process was stakeholder-initiated, stakeholder-driven, and included stakeholders during each phase. Phases included conceptualization, initial selection of biota and radionuclides, refinement of biota and radionuclide target lists, collection of biota, selection of biota and radionuclides for analysis, and selection of biota, tissues, and radionuclides for bioindicators. The process produced site-specific information on biota availability and on radionuclide levels that led to selection of site-appropriate bioindicators. I suggest that the lengthy, iterative, stakeholder-driven process described in this paper results in selection of bioindicators that are accepted by biologists, public health personnel, public-policy makers, resource agencies, regulatory agencies, subsistence hunters/fishers, and a wide

  11. A model for selecting bioindicators to monitor radionuclide concentrations using Amchitka Island in the Aleutians as a case study

    SciTech Connect

    Burger, Joanna

    2007-11-15

    World War II and the Cold War have left the Unites States, and other Nations, with massive cleanup and remediation tasks for radioactive and other legacy hazardous wastes. While some sites can be cleaned up to acceptable residential risk levels, others will continue to hold hazardous wastes, which must be contained and monitored to protect human health and the environment. While media (soil, sediment, groundwater) monitoring is the usual norm at many radiological waste sites, for some situations (both biological and societal), biomonitoring may provide the necessary information to assure greater peace of mind for local and regional residents, and to protect ecologically valuable buffer lands or waters. In most cases, indicators are selected using scientific expertise and a literature review, but not all selected indicators will seem relevant to stakeholders. In this paper, I provide a model for the inclusion of stakeholders in the development of bioindicators for assessing radionuclide levels of biota in the marine environment around Amchitka Island, in the Aleutian Chain of Alaska. Amchitka was the site of three underground nuclear tests from 1965 to 1971. The process was stakeholder-initiated, stakeholder-driven, and included stakeholders during each phase. Phases included conceptualization, initial selection of biota and radionuclides, refinement of biota and radionuclide target lists, collection of biota, selection of biota and radionuclides for analysis, and selection of biota, tissues, and radionuclides for bioindicators. The process produced site-specific information on biota availability and on radionuclide levels that led to selection of site-appropriate bioindicators. I suggest that the lengthy, iterative, stakeholder-driven process described in this paper results in selection of bioindicators that are accepted by biologists, public health personnel, public-policy makers, resource agencies, regulatory agencies, subsistence hunters/fishers, and a wide

  12. Select tissue mineral concentrations and chronic wasting disease status in mule deer from North-central Colorado.

    PubMed

    Wolfe, Lisa L; Conner, Mary M; Bedwell, Cathy L; Lukacs, Paul M; Miller, Michael W

    2010-07-01

    Trace mineral imbalances have been suggested as having a causative or contributory role in chronic wasting disease (CWD), a prion disease of several North American cervid species. To begin exploring relationships between tissue mineral concentrations and CWD in natural systems, we measured liver tissue concentrations of copper, manganese, and molybdenum in samples from 447 apparently healthy, adult (> or = 2 yr old) mule deer (Odocoileus hemionus) culled or vehicle killed from free-ranging populations in north-central Colorado, United States, where CWD occurs naturally; we also measured copper concentrations in brain-stem (medulla oblongata at the obex) tissue from 181 of these deer. Analyses revealed a wide range of concentrations of all three minerals among sampled deer (copper: 5.6-331 ppm in liver, 1.5-31.9 ppm in obex; manganese: 0.1-21.4 ppm in liver; molybdenum: 0.5-4.0 ppm in liver). Bayesian multiple regression analysis revealed a negative association between obex copper (-0.097; 95% credible interval -0.192 to -0.006) and the probability of sampled deer also being infected with CWD, as well as a positive association between liver manganese (0.158; 95% credible interval 0.066 to 0.253) and probability of infection. We could not discern whether the tendencies toward lower brain-stem copper concentrations or higher systemic manganese concentrations in infected deer preceded prion infection or rather were the result of infection and its subsequent effects, although the distribution of trace mineral concentrations in infected deer seemed more suggestive of the latter.

  13. Identification of selected in vitro generated phase-I metabolites of the steroidal selective androgen receptor modulator MK-0773 for doping control purposes.

    PubMed

    Lagojda, Andreas; Kuehne, Dirk; Krug, Oliver; Thomas, Andreas; Wigger, Tina; Karst, Uwe; Schänzer, Wilhelm; Thevis, Mario

    2016-01-01

    Research into developing anabolic agents for various therapeutic purposes has been pursued for decades. As the clinical utility of anabolic-androgenic steroids has been found to be limited because of their lack of tissue selectivity and associated off-target effects, alternative drug entities have been designed and are commonly referred to as selective androgen receptor modulators (SARMs). While most of these SARMs are of nonsteroidal structure, the drug candidate MK-0773 comprises a 4-aza-steroidal nucleus. Besides the intended therapeutic use, SARMs have been found to be illicitly distributed and misused as doping agents in sport, necessitating frequently updated doping control analytical assays. As steroidal compounds reportedly undergo considerable metabolic transformations, the phase-I metabolism of MK-0773 was simulated using human liver microsomal (HLM) preparations and electrochemical conversion. Subsequently, major metabolic products were identified and characterized employing liquid chromatography-high-resolution/high- accuracy tandem mass spectrometry with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) as well as nuclear magnetic resonance (NMR) spectroscopy. MK-0773 produced numerous phase-I metabolites under the chosen in vitro incubation reactions, mostly resulting from mono- and bisoxygenation of the steroid. HLM yielded at least 10 monooxygenated species, while electrochemistry-based experiments resulted predominantly in three monohydroxylated metabolites. Elemental composition data and product ion mass spectra were generated for these analytes, ESI/APCI measurements corroborated the formation of at least two N-oxygenated metabolites, and NMR data obtained from electrochemistry-derived products supported structures suggested for three monohydroxylated compounds. Hereby, the hydroxylation of the A-ring located N- bound methyl group was found to be of particular intensity. In the absence of controlled elimination studies, the

  14. Identification of selected in vitro generated phase-I metabolites of the steroidal selective androgen receptor modulator MK-0773 for doping control purposes.

    PubMed

    Lagojda, Andreas; Kuehne, Dirk; Krug, Oliver; Thomas, Andreas; Wigger, Tina; Karst, Uwe; Schänzer, Wilhelm; Thevis, Mario

    2016-01-01

    Research into developing anabolic agents for various therapeutic purposes has been pursued for decades. As the clinical utility of anabolic-androgenic steroids has been found to be limited because of their lack of tissue selectivity and associated off-target effects, alternative drug entities have been designed and are commonly referred to as selective androgen receptor modulators (SARMs). While most of these SARMs are of nonsteroidal structure, the drug candidate MK-0773 comprises a 4-aza-steroidal nucleus. Besides the intended therapeutic use, SARMs have been found to be illicitly distributed and misused as doping agents in sport, necessitating frequently updated doping control analytical assays. As steroidal compounds reportedly undergo considerable metabolic transformations, the phase-I metabolism of MK-0773 was simulated using human liver microsomal (HLM) preparations and electrochemical conversion. Subsequently, major metabolic products were identified and characterized employing liquid chromatography-high-resolution/high- accuracy tandem mass spectrometry with electrospray (ESI) and atmospheric pressure chemical ionization (APCI) as well as nuclear magnetic resonance (NMR) spectroscopy. MK-0773 produced numerous phase-I metabolites under the chosen in vitro incubation reactions, mostly resulting from mono- and bisoxygenation of the steroid. HLM yielded at least 10 monooxygenated species, while electrochemistry-based experiments resulted predominantly in three monohydroxylated metabolites. Elemental composition data and product ion mass spectra were generated for these analytes, ESI/APCI measurements corroborated the formation of at least two N-oxygenated metabolites, and NMR data obtained from electrochemistry-derived products supported structures suggested for three monohydroxylated compounds. Hereby, the hydroxylation of the A-ring located N- bound methyl group was found to be of particular intensity. In the absence of controlled elimination studies, the

  15. Generation of a Single Chain Antibody Variable Fragment (scFv) to Sense Selectively RhoB Activation

    PubMed Central

    Chinestra, Patrick; Olichon, Aurélien; Medale-Giamarchi, Claire; Lajoie-Mazenc, Isabelle; Gence, Rémi; Inard, Cyril; Ligat, Laetitia; Faye, Jean-Charles; Favre, Gilles

    2014-01-01

    Determining the cellular level of activated form of RhoGTPases is of key importance to understand their regulatory functions in cell physiopathology. We previously reported scFvC1, that selectively bind to the GTP-bound form of RhoA, RhoB and RhoC. In this present study we generate, by molecular evolution, a new phage library to isolate scFvs displaying high affinity and selectivity to RhoA and RhoB. Using phage display affinity maturation against the GTP-locked mutant RhoAL63, we isolated scFvs against RhoA active conformation that display Kd values at the nanomolar range, which corresponded to an increase of affinity of three orders of magnitude compared to scFvC1. Although a majority of these evolved scFvs remained selective towards the active conformation of RhoA, RhoB and RhoC, we identified some scFvs that bind to RhoA and RhoC but not to RhoB activated form. Alternatively, we performed a substractive panning towards RhoB, and isolated the scFvE3 exhibiting a 10 times higher affinity for RhoB than RhoA activated forms. We showed the peculiar ability of scFvE3 to detect RhoB but not RhoA GTP-bound form in cell extracts overexpressing Guanine nucleotide Exchange Factor XPLN as well as in EGF stimulated HeLa cells. Our results demonstrated the ability of scFvs to distinguish RhoB from RhoA GTP-bound form and provide new selective tools to analyze the cell biology of RhoB GTPase regulation. PMID:25365345

  16. SAS2H Generated Isotopic Concentrations For B&W 15X15 PWR Assembly (SCPB:N/A)

    SciTech Connect

    J.W. Davis

    1996-08-29

    This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development Department (WPDD) to provide pressurized water reactor (PWR) isotopic composition data as a function of time for use in criticality analyses. The objectives of this evaluation are to generate burnup and decay dependant isotopic inventories and to provide these inventories in a form which can easily be utilized in subsequent criticality calculations.

  17. Differences in Parental Involvement Typologies among Baby Boomers, Generation X, and Generation Y Parents: A Study of Select Bay Area Region of Houston Elementary Schools

    ERIC Educational Resources Information Center

    Veloz, Elizabeth Andrea

    2010-01-01

    The purpose of this study was to determine whether differences existed among generations (Baby Boomers, Generation X, and Generation Y) regarding the levels of parental involvement within each of these generations. Also examined were additional factors such as the parents. socioeconomic status, educational level, marital status, and ethnicity. The…

  18. Trends in radionuclide concentrations for selected wildlife and food products near the Hanford Site from 1971 through 1988

    SciTech Connect

    Eberhardt, L.E.; Cadwell, L.L.; Price, K.R.; Carlile, D.W.; Alaska Dept. of Fish and Game, Juneau, AK )

    1989-09-01

    From 1971 through 1988 at least 40 species of wildlife and 27 different types of food products were collected and analyzed for radionuclides as part of the Pacific Northwest Laboratory (PNL) Environmental Monitoring Program. This report summarizes the results of these analyses for sample types collected for all or most of the 18-year period. The objectives of this summary investigation were to identify long-term trends or significant year-to-year changes in radionuclide concentrations and, if possible, relate any observed changes in radionuclide concentrations to their sources and probable causes. Statistical techniques were employed to test for long-term trends. Conspicuous short-term changes in radionuclide concentrations were identified from inspection of the data. 30 refs., 16 figs., 4 tabs.

  19. Solvent-vapor concentration imparts selectivity on the propagation front during polymorphic transformation in molecular-semiconductor thin films

    NASA Astrophysics Data System (ADS)

    Purdum, Geoffrey; Gessner, Thomas; Weitz, R. Thomas; Loo, Yueh-Lin

    Post-deposition processing allows precise control over the structural development of molecular-semiconductor thin films. In particular, solvent-vapor annealing converts thin films of a core-chlorinated naphthalene diimide from its triclinic polymorph to its monoclinic polymorph. By tuning the concentration of solvent vapor, we can simultaneously impact the morphology of the resulting monoclinic thin film. At low solvent-vapor concentrations, transformation in-plane is isotropic; we observe comparable transformation rates along the b- and c-axes, resulting in plate-like domains. At high solvent-vapor concentrations, transformation along the c-axis is instead favored, resulting in the formation of needle-like domains. Extended solvent-vapor annealing at these conditions can lead to isolated needles in the active channels of field-effect transistors; these devices exhibit electron mobilities exceeding 1 cm2/Vs.

  20. Sea ice concentration from satellite passive microwave algorithms: inter-comparison, validation and selection of an optimal algorithm

    NASA Astrophysics Data System (ADS)

    Ivanova, Natalia; Pedersen, Leif T.; Lavergne, Thomas; Tonboe, Rasmus T.; Saldo, Roberto; Mäkynen, Marko; Heygster, Georg; Rösel, Anja; Kern, Stefan; Dybkjær, Gorm; Sørensen, Atle; Brucker, Ludovic; Shokr, Mohammed; Korosov, Anton; Hansen, Morten W.

    2015-04-01

    Sea ice concentration (SIC) has been derived globally from satellite passive microwave observations since the 1970s by a multitude of algorithms. However, existing datasets and algorithms, although agreeing in the large-scale picture, differ substantially in the details and have disadvantages in summer and fall due to presence of melt ponds and thin ice. There is thus a need for understanding of the causes for the differences and identifying the most suitable method to retrieve SIC. Therefore, during the ESA Climate Change Initiative effort 30 algorithms have been implemented, inter-compared and validated by a standardized reference dataset. The algorithms were evaluated over low and high sea ice concentrations and thin ice. Based on the findings, an optimal approach to retrieve sea ice concentration globally for climate purposes was suggested and validated. The algorithm was implemented with atmospheric correction and dynamical tie points in order to produce the final sea ice concentration dataset with per-pixel uncertainties. The issue of melt ponds was addressed in particular because they are interpreted as open water by the algorithms and thus SIC can be underestimated by up to 40%. To improve our understanding of this issue, melt-pond signatures in AMSR2 images were investigated based on their physical properties with help of observations of melt pond fraction from optical (MODIS and MERIS) and active microwave (SAR) satellite measurements.

  1. Real Time Selective Harmonic Minimization for Multilevel Inverters Connected to Solar Panels Using Artificial Neural Network Angle Generation

    SciTech Connect

    Tolbert, Leon M; Ozpineci, Burak; Filho, Faete; Cao, Yue

    2011-01-01

    This work approximates the selective harmonic elimination problem using artificial neural networks (ANNs) to generate the switching angles in an 11-level full-bridge cascade inverter powered by five varying dc input sources. Each of the five full bridges of the cascade inverter was connected to a separate 195-W solar panel. The angles were chosen such that the fundamental was kept constant and the low-order harmonics were minimized or eliminated. A nondeterministic method is used to solve the system for the angles and to obtain the data set for the ANN training. The method also provides a set of acceptable solutions in the space where solutions do not exist by analytical methods. The trained ANN is a suitable tool that brings a small generalization effect on the angles' precision and is able to perform in real time (50-/60-Hz time window).

  2. Photosynthetic pigment concentrations, gas exchange and vegetative growth for selected monocots and dicots treated with two contrasting coal fly ashes

    SciTech Connect

    Yunusa, I.A.M.; Burchett, M.D.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Skilbeck, C.G.

    2009-07-15

    There is uncertainty as to the rates of coal fly ash needed for optimum physiological processes and growth. In the current study we tested the hyothesis that photosynthetic pigments concentrations and CO{sub 2} assimilation (A) are more sensitive than dry weights in plants grown on media amended with coal fly ash. We applied the Terrestrial Plant Growth Test (Guideline 208) protocols of the Organization for Economic Cooperation and Development (OECD) to monocots (barley (Hordeum vulgare) and ryegrass (Secale cereale)) and dicots (canola (Brasica napus), radish (Raphanus sativus), field peas (Pisum sativum), and lucerne (Medicago sativa)) on media amended with fly ashes derived from semi-bituminous (gray ash) or lignite (red ash) coals at rates of 0, 2.5, 5.0, 10, or 20 Mg ha(-1). The red ash had higher elemental concentrations and salinity than the gray ash. Fly ash addition had no significant effect on germination by any of the six species. At moderate rates ({<=}10 Mg ha{sup -1}) both ashes increased (P < 0.05) growth rates and concentrations of chlorophylls a and b, but reduced carotenoid concentrations. Addition of either ash increased A in radish and transpiration in barley. Growth rates and final dry weights were reduced for all of the six test species when addition rates exceeded 10 Mg ha{sup -1} for gray ash and 5 Mg ha{sup -1} for red ash. We concluded that plant dry weights, rather than pigment concentrations and/or instantaneous rates of photosynthesis, are more consistent for assessing subsequent growth in plants supplied with fly ash.

  3. Photosynthetic pigment concentrations, gas exchange and vegetative growth for selected monocots and dicots treated with two contrasting coal fly ashes.

    PubMed

    Yunusa, Isa A M; Burchett, Margaret D; Manoharan, V; Desilva, D Lionel; Eamus, Derek; Skilbeck, C Greg

    2009-01-01

    There is uncertainty as to the rates of coal fly ash needed for optimum physiological processes and growth. In the current study we tested the hypothesis that photosynthetic pigments concentrations and CO(2) assimilation (A) are more sensitive than dry weights in plants grown on media amended with coal fly ash. We applied the Terrestrial Plant Growth Test (Guideline 208) protocols of the Organization for Economic Cooperation and Development (OECD) to monocots [barley (Hordeum vulgare) and ryegrass (Secale cereale)] and dicots [canola (Brasica napus), radish (Raphanus sativus), field peas (Pisum sativum), and lucerne (Medicago sativa)] on media amended with fly ashes derived from semi-bituminous (gray ash) or lignite (red ash) coals at rates of 0, 2.5, 5.0, 10, or 20 Mg ha(-1). The red ash had higher elemental concentrations and salinity than the gray ash. Fly ash addition had no significant effect on germination by any of the six species. At moderate rates (concentrations of chlorophylls a and b, but reduced carotenoid concentrations. Addition of either ash increased A in radish and transpiration in barley. Growth rates and final dry weights were reduced for all of the six test species when addition rates exceeded 10 Mg ha(-1) for gray ash and 5 Mg ha(-1) for red ash. We concluded that plant dry weights, rather than pigment concentrations and/or instantaneous rates of photosynthesis, are more consistent for assessing subsequent growth in plants supplied with fly ash.

  4. Self-generated concentration and modulus gradient coating design to protect Si nano-wire electrodes during lithiation.

    PubMed

    Kim, Sung-Yup; Ostadhossein, Alireza; van Duin, Adri C T; Xiao, Xingcheng; Gao, Huajian; Qi, Yue

    2016-02-01

    Surface coatings as artificial solid electrolyte interphases have been actively pursued as an effective way to improve the cycle efficiency of nanostructured Si electrodes for high energy density lithium ion batteries, where the mechanical stability of the surface coatings on Si is as critical as Si itself. However, the chemical composition and mechanical property change of coating materials during the lithiation and delithiation process imposed a grand challenge to design coating/Si nanostructure as an integrated electrode system. In our work, we first developed reactive force field (ReaxFF) parameters for Li-Si-Al-O materials to simulate the lithiation process of Si-core/Al2O3-shell and Si-core/SiO2-shell nanostructures. With reactive dynamics simulations, we were able to simultaneously track and correlate the lithiation rate, compositional change, mechanical property evolution, stress distributions, and fracture. A new mechanics model based on these varying properties was developed to determine how to stabilize the coating with a critical size ratio. Furthermore, we discovered that the self-accelerating Li diffusion in Al2O3 coating forms a well-defined Li concentration gradient, leading to an elastic modulus gradient, which effectively avoids local stress concentration and mitigates crack propagation. Based on these results, we propose a modulus gradient coating, softer outside, harder inside, as the most efficient coating to protect the Si electrode surface and improve its current efficiency.

  5. Self-generated concentration and modulus gradient coating design to protect Si nano-wire electrodes during lithiation.

    PubMed

    Kim, Sung-Yup; Ostadhossein, Alireza; van Duin, Adri C T; Xiao, Xingcheng; Gao, Huajian; Qi, Yue

    2016-02-01

    Surface coatings as artificial solid electrolyte interphases have been actively pursued as an effective way to improve the cycle efficiency of nanostructured Si electrodes for high energy density lithium ion batteries, where the mechanical stability of the surface coatings on Si is as critical as Si itself. However, the chemical composition and mechanical property change of coating materials during the lithiation and delithiation process imposed a grand challenge to design coating/Si nanostructure as an integrated electrode system. In our work, we first developed reactive force field (ReaxFF) parameters for Li-Si-Al-O materials to simulate the lithiation process of Si-core/Al2O3-shell and Si-core/SiO2-shell nanostructures. With reactive dynamics simulations, we were able to simultaneously track and correlate the lithiation rate, compositional change, mechanical property evolution, stress distributions, and fracture. A new mechanics model based on these varying properties was developed to determine how to stabilize the coating with a critical size ratio. Furthermore, we discovered that the self-accelerating Li diffusion in Al2O3 coating forms a well-defined Li concentration gradient, leading to an elastic modulus gradient, which effectively avoids local stress concentration and mitigates crack propagation. Based on these results, we propose a modulus gradient coating, softer outside, harder inside, as the most efficient coating to protect the Si electrode surface and improve its current efficiency. PMID:26760786

  6. Changes in Streamflow, Concentrations, and Loads in Selected Nontidal Basins in the Chesapeake Bay Watershed, 1985-2006

    USGS Publications Warehouse

    Langland, Michael J.; Moyer, Douglas; Blomquist, Joel

    2007-01-01

    Water-quality and streamflow data from 34 sites in nontidal parts of the Chesapeake Bay watershed are presented to document annual nutrient and sediment loads and trends for 1985 through 2006, as part of an annual evaluation of water-quality conditions by the U.S. EPA Chesapeake Bay Program. This study presents the results of trends analysis for streamflow, loads, and concentrations. Annual mean flow to the bay for 2006 (78,650 cubic feet per second) was approximately 1 percent above the long-term annual mean flow from 1937 to 2005. Total freshwater flow entering the bay for the summer season (July-August-September) was the only season classified as 'wet' in 2006. For the period 1985 through 2006, streamflow was significantly increasing at two of the 34 sites. Observed (bias-corrected) concentration summaries indicate higher ranges in concentrations of total nitrogen in the northern major river basins (Pennsylvania, Maryland, and northern Virginia) than in the southern basins in Virginia. Results indicate almost half of the monitoring sites in the northern basins exhibited significant downward bias-corrected concentration trends in total nitrogen over time; results were similar for total phosphorus and sediment. Generally, loads for all constituents at the nine River Input Monitoring Program (RIM) sites, which comprise 78 percent of the streamflow entering the bay, were lower in 2006 than in 2005. The loads for total nitrogen are below the long-term average loads at eight of the nine RIM sites and total phosphorus and sediment loads are also below the long-term average at seven RIM sites. Combined annual mean total nitrogen flow-weighted concentrations from the nine RIM sites indicated an upward tendency in 2006; in contrast, total phosphorus and sediment indicated a downward tendency. From 1990 to 2006 for the 9 RIM sites, the mean concentrations of total nitrogen, total phosphorus, and sediment were 3.49, 0.195, and 116 milligrams per liter, respectively. Flow

  7. Visual working memory modulates low-level saccade target selection: evidence from rapidly generated saccades in the global effect paradigm.

    PubMed

    Hollingworth, Andrew; Matsukura, Michi; Luck, Steven J

    2013-11-04

    In three experiments, we examined the influence of visual working memory (VWM) on the metrics of saccade landing position in a global effect paradigm. Participants executed a saccade to the more eccentric object in an object pair appearing on the horizontal midline, to the left or right of central fixation. While completing the saccade task, participants maintained a color in VWM for an unrelated memory task. Either the color of the saccade target matched the memory color (target match), the color of the distractor matched the memory color (distractor match), or the colors of neither object matched the memory color (no match). In the no-match condition, saccades tended to land at the midpoint between the two objects: the global, or averaging, effect. However, when one of the two objects matched VWM, the distribution of landing position shifted toward the matching object, both for target match and for distractor match. VWM modulation of landing position was observed even for the fastest quartile of saccades, with a mean latency as low as 112 ms. Effects of VWM on such rapidly generated saccades, with latencies in the express-saccade range, indicate that VWM interacts with the initial sweep of visual sensory processing, modulating perceptual input to oculomotor systems and thereby biasing oculomotor selection. As a result, differences in memory match produce effects on landing position similar to the effects generated by differences in physical salience.

  8. Removal of humic substances from reverse osmosis (RO) and nanofiltration (NF) concentrated leachate using continuously ozone generation-reaction treatment equipment.

    PubMed

    Wang, Huawei; Wang, Ya-Nan; Li, Xiaoyue; Sun, Yingjie; Wu, Hao; Chen, Dali

    2016-10-01

    Concentrated leachate from membrane treatment process, which contains large amount of difficult-to-degrade humic substances, can induce potential hazards to ecological environment. In this study, the concentrated leachates from reverse osmosis (RO) and nanofiltration (NF) were treated by continuous ozone generating-reaction integrated equipment, and the removal characteristics of humic substances were analyzed using gel filtration chromatography (GFC), excitation-emission matrix fluorescence spectroscopy (EEM), XAD-8 resin fractionation, and Fourier transform infrared spectroscopy (FTIR). The results of XRD-8 fractionation and SUVA254 showed that the humic substances including humic acid (HA) and fulvic acid (FA), were effectively removed along with the breakdown of aromatic hydrocarbons and decrease in the degree of humification during the ozonation process. After 110min of reaction, HA in both concentrated leachates was completely removed. GFC analysis indicated that both concentrated leachates had much broader distribution after the degradation. The high molecular weight (MW) organic matter was transformed into low molecular weight of <10kDa. The majority of high MW organics in NF concentrate were converted to low MW molecules of 10kDa-1kDa, while those in RO concentrate were decomposed to small MW molecules of <1kDa. The results of EEM analysis implied that the degradation of HA and FA led to a significant decrease in the fluorescence intensity. Though the effluent of two concentrated leachate did not meet the maximum allowable criterion for leachate direct or indirect discharge standard in China, the composition and properties of organic matters in concentrated leachate were changed significantly after entire ozonation reaction, which would be conducive to the further biological treatment or other advanced treatment. PMID:27478023

  9. Selection of AT-Tank Analysis Equipment for Determining Completion of Mixing and Particle Concentration in Hanford Waste Tanks

    SciTech Connect

    Dodson, M.G.; Ozanich, R.M.; Bailey, S.A.

    1999-06-10

    This document will describe the functions and requirements of the at-tank analysis system concept developed by the Robotics Technology Development Program (RTDP) and Berkeley Instruments. It will discuss commercially available at-tank analysis equipment, and compare those that meet the stated functions and requirements. This is followed by a discussion of the considerations used in the selection of instrumentation for the concept design, and an overall description of the proposed at-tank analysis system.

  10. Water quality in Indiana: trends in concentrations of selected nutrients, metals, and ions in streams, 2000-10

    USGS Publications Warehouse

    Risch, Martin R.; Bunch, Aubrey R.; Vecchia, Skip V.; Martin, Jeffrey D.; Baker, Nancy T.

    2014-01-01

    Statistically significant trends were identified that included 167 downward trends and 83 upward trends. The Kankakee River Basin had the most significant upward trends while the most significant downward trends were in the Whitewater River Basin, the Lake Michigan Basin, and the Patoka River Basin. For most constituents, a majority of sites had significant downward trends. Two streams in the Lake Michigan Basin have shown substantial decreases in most constituents. The West Fork White River near Indianapolis, Indiana, showed increases in nitrate and phosphorus and the Kankakee River Basin showed increases in copper, zinc, chloride, sulfate, and hardness. Upward trends in nutrients were identified at a few sites, but most nutrient trends were downward. Upward trends in metals corresponded with relatively small concentration increases while downward trends involved considerably larger concentration changes. Downward trends in chloride, sulfate, and suspended solids were observed statewide, but upward trends in hardness were observed in the northern half of Indiana.

  11. Application of computational neural networks in predicting atmospheric pollutant concentrations due to fossil-fired electric power generation

    SciTech Connect

    El-Hawary, F.

    1995-12-31

    The ability to accurately predict the behavior of a dynamic system is of essential importance in monitoring and control of complex processes. In this regard recent advances in neural-net based system identification represent a significant step toward development and design of a new generation of control tools for increased system performance and reliability. The enabling functionality is the one of accurate representation of a model of a nonlinear and nonstationary dynamic system. This functionality provides valuable new opportunities including: (1) The ability to predict future system behavior on the basis of actual system observations, (2) On-line evaluation and display of system performance and design of early warning systems, and (3) Controller optimization for improved system performance. In this presentation, we discuss the issues involved in definition and design of learning control systems and their impact on power system control. Several numerical examples are provided for illustrative purpose.

  12. Simulation of a photo-solar generator for an optimal output by a parabolic photovoltaic concentrator of Stirling engine type

    NASA Astrophysics Data System (ADS)

    Kaddour, A.; Benyoucef, B.

    Solar energy is the source of the most promising energy and the powerful one among renewable energies. Photovoltaic electricity (statement) is obtained by direct transformation of the sunlight into electricity, by means of cells statement. Then, we study the operation of cells statement by the digital simulation with an aim of optimizing the output of the parabolic concentrator of Stirling engine type. The Greenius software makes it possible to carry out the digital simulation in 2D and 3D and to study the influence of the various parameters on the characteristic voltage under illumination of the cell. The results obtained enabled us to determine the extrinsic factors which depend on the environment and the intrinsic factors which result from the properties of materials used.

  13. Concentration dependent selection of targets by an SR splicing regulator results in tissue-specific RNA processing.

    PubMed

    Qi, Junlin; Su, Shihuang; McGuffin, M Elaine; Mattox, William

    2006-01-01

    The splicing factor Transformer-2 (Tra2) is expressed almost ubiquitously in Drosophila adults, but participates in the tissue-specific regulation of splicing in several RNAs. In somatic tissues Tra2 participates in the activation of sex-specific splice sites in doublesex and fruitless pre-mRNAs. In the male germline it affects splicing of other transcripts and represses removal of the M1 intron from its own pre-mRNA. Here we test the hypothesis that the germline specificity of M1 repression is determined by tissue-specific differences in Tra2 concentration. We find that Tra2 is expressed at higher levels in primary spermatocytes of males than in other cell types. Increased Tra2 expression in other tissues reduces viability in a manner consistent with known dose-dependent effects of excessive Tra2 expression in the male germline. Somatic cells were found to be competent to repress M1 splicing if the level of Tra2 transcription was raised above endogenous concentrations. This suggests not only that M1 repression is restricted to the germline by a difference in Tra2 transcription levels but also that the protein's threshold concentration for M1 regulation differs from that of doublesex and fruitless RNAs. We propose that quantitative differences in regulator expression can give rise to cell-type-specific restrictions in splicing.

  14. Characterization of background concentrations in upper Manhattan, New York apartments for select contaminants identified in World Trade Center dust.

    PubMed

    Tang, Kai M; Nace, Charles G; Lynes, Carol L; Maddaloni, Mark A; LaPosta, Dore; Callahan, Kathleen C

    2004-12-15

    Residential indoor concentration of asbestos, lead, synthetic vitreous fiber (SVF), crystalline silica, calcite, gypsum, dioxin, and polycyclic aromatic hydrocarbons (PAHs) were measured in 25 residences and 9 building-interior common areas in upper Manhattan, NY. This was done to characterize the background levels of contaminants, identified in dust related to the collapse of the World Trade Center towers, at locations that were minimally impacted by the dust fallout. The study was initiated due to the paucity of background concentrations on building-related materials and combustion byproducts in urban residential dwellings. Asbestos, lead, SVF, crystalline silica, and dioxin were detected at very low concentration at some locations, and many samples tested below their respective analysis detection limits. Almost all of the environmental samples for PAHs, calcite, gypsum, and certain other building materials tested below their respective analysis detection limits. A comparative analysis to the limited literature data showed general agreement with the values found in this study. This study provides insight into the levels of these contaminants in lower Manhattan residential buildings prior to the attack, and these data will serve to enhance the available database for characterizing indoor environments for these contaminants.

  15. Copper, cadmium, and zinc concentrations in aquatic food chains from the Upper Sacramento River (California) and selected tributaries

    USGS Publications Warehouse

    Saiki, M.K.; Castleberry, D. T.; May, T. W.; Martin, B.A.; Bullard, F. N.

    1995-01-01

    Metals enter the Upper Sacramento River above Redding, California, primarily through Spring Creek, a tributary that receives acid-mine drainage from a US EPA Superfund site known locally as Iron Mountain Mine. Waterweed (Elodea canadensis) and aquatic insects (midge larvae, Chironomidae; and mayfly nymphs, Ephemeroptera) from the Sacramento River downstream from Spring Creek contained much higher concentrations of copper (Cu), cadmium (Cd), and zinc (Zn) than did similar taxa from nearby reference tributaries not exposed to acid-mine drainage. Aquatic insects from the Sacramento River contained especially high maximum concentrations of Cu (200 mg/kg dry weight in midge larvae), Cd (23 mg/kg dry weight in mayfly nymphs), and Zn (1,700 mg/kg dry weight in mayfly nymphs). Although not always statistically significant, whole-body concentrations of Cu, Cd, and Zn in fishes (threespine stickleback, Gasterosteus aculeatus; Sacramento sucker, Catostomus occidentalis; Sacramento squawfish, Ptychocheilus grandis; and chinook salmon, Oncorhynchus tshawytasch) from the Sacramento River were generally higher than in fishes from the reference tributaries.

  16. Concentrations of tritium and strontium-90 in water from selected wells at the Idaho National Engineering Laboratory after purging one, two, and three borehole volumes

    USGS Publications Warehouse

    Bartholomay, R.C.

    1993-01-01

    Water from 11 wells completed in the Snake River Plain aquifer at the Idaho National Engineering Laboratory was sampled as part of the U.S. Geological Survey's quality assurance program to determine the effect of purging different borehole volumes on tritium and strontium-90 concentrations. Wells were selected for sampling on the basis of the length of time it took to purge a borehole volume of water. Samples were collected after purging one, two, and three borehole volumes. The U.S. Department of Energy's Radiological and Environmental Sciences Laboratory provided analytical services. Statistics were used to determine the reproducibility of analytical results. The comparison between tritium and strontium-90 concentrations after purging one and three borehole volumes and two and three borehole volumes showed that all but two sample pairs with defined numbers were in statistical agreement. Results indicate that concentrations of tritium and strontium-90 are not affected measurably by the number of borehole volumes purged.

  17. The effect of heavy metal concentration and soil pH on the abundance of selected microbial groups within ArcelorMittal Poland steelworks in Cracow.

    PubMed

    Lenart, Anna; Wolny-Koładka, Katarzyna

    2013-01-01

    The present study aimed to identify the effect of heavy metal concentration and soil pH on the abundance of the selected soil microorganisms within ArcelorMittal Poland steelworks, Cracow. The analysis included 20 soil samples, where the concentration of Fe, Zn, Cd, Pb, Ni, Cu, Mn, Cr and soil pH were evaluated together with the number of mesophilic bacteria, fungi, Actinomycetes and Azotobacter spp. In the majority of samples soil pH was alkaline. The limits of heavy metals exceeded in eight samples and in one sample, the concentration of Zn exceeded 31-fold. Chromium was the element which most significantly limited the number of bacteria and Actinomycetes.

  18. Mutant-prevention concentration and mechanism of resistance in clinical isolates and enrofloxacin/marbofloxacin-selected mutants of Escherichia coli of canine origin.

    PubMed

    Gebru, Elias; Choi, Myung-Jin; Lee, Seung-Jin; Damte, Dereje; Park, Seung Chun

    2011-10-01

    The antibacterial activity and selection of resistant bacteria, along with mechanisms of fluoroquinolone resistance, were investigated by integrating the static [MIC or mutant-prevention concentration (MPC)] and in vitro dynamic model approaches using Escherichia coli isolates from diseased dogs. Using the dynamic models, selected E. coli strains and enrofloxacin and marbofloxacin at a range of simulated area under concentration-time curve over a 24 h interval (AUC(24 h))/MIC ratios were investigated. Our results indicated increasing losses in susceptibility of E. coli upon continuous exposure to enrofloxacin and marbofloxacin in vitro. This effect was transferable to other fluoroquinolones, as well as to structurally unrelated drugs. Our results also confirmed an AUC(24 h)/MIC (AUC(24 h)/MPC)-dependent antibacterial activity and selection of resistant E. coli mutants, in which maximum losses in fluoroquinolone susceptibility occurred at simulated AUC(24 h)/MIC ratios of 40-60. AUC(24 h)/MPC ratios of 39 (enrofloxacin) and 32 (marbofloxacin) were considered protective against the selection of resistant mutants of E. coli. Integrating our MIC and MPC data with published pharmacokinetic information in dogs revealed a better effect of the conventional dosing regimen of marbofloxacin than that of enrofloxacin in restricting the selection of resistant mutants of E. coli. Target mutations, especially at codon 83 (serine to leucine) of gyrA, and overexpression of efflux pumps contributed to resistance development in both clinically resistant and in vitro-selected mutants of E. coli. We also report here a previously undescribed mutation at codon 116 of parC in two laboratory-derived resistant mutants of E. coli. Additional studies would determine the exact role of this mutation in fluoroquinolone susceptibility, as well as establish the importance of our findings in the clinical setting.

  19. An exploratory analysis of the relationship between ambient ozone and particulate matter concentrations during early pregnancy and selected birth defects in Texas.

    PubMed

    Vinikoor-Imler, Lisa C; Stewart, Thomas G; Luben, Thomas J; Davis, J Allen; Langlois, Peter H

    2015-07-01

    We performed an exploratory analysis of ozone (O3) and fine particulate matter (PM2.5) concentrations during early pregnancy and multiple types of birth defects. Data on births were obtained from the Texas Birth Defects Registry (TBDR) and the National Birth Defects Prevention Study (NBDPS) in Texas. Air pollution concentrations were previously determined by combining modeled air pollution concentrations with air monitoring data. The analysis generated hypotheses for future, confirmatory studies; although many of the observed associations were null. The hypotheses are provided by an observed association between O3 and craniosynostosis and inverse associations between PM2.5 and septal and obstructive heart defects in the TBDR. Associations with PM2.5 for septal heart defects and ventricular outflow tract obstructions were null using the NBDPS. Both the TBDR and the NBPDS had inverse associations between O3 and septal heart defects. Further research to confirm the observed associations is warranted.

  20. Effect of selected dietary buffers upon utilization of concentrate- or roughage-based cattle diets: laboratory studies.

    PubMed

    Hall, M W; Thomas, E E

    1984-07-01

    Four chemical buffers were evaluated with in vitro rumen fermentation studies using both an 80% concentrate and a 50% roughage diet. Treatments included a positive control (PC), negative control (NC) and four buffered diets in which 500 mg of either CaHPO4, CaCO3, NaHCO3 or Na4P2O7 were added. The PC consisted of unbuffered diet with one part rumen fluid and four parts McDougall's artificial saliva. In the unbuffered NC and buffered treatments, three-fourths of the artificial saliva was replaced by iso-osmotic saline. In the concentrate-based diet, NaHCO3 and Na4P2O7 elevated (P less than .05) pH above the NC. Starch digestion and total VFA were increased (P less than .05) by NaHCO3 compared with the NC while the molar proportion of individual VFA was not altered. Tetrasodium pyrophosphate had no effect on starch digestion or total VFA, but did increase (P less than .05) the molar proportion of acetic acid. Regarding the 50% roughage diet, both NaHCO3 and Na4P2O7 elevated (P less than .05) starch and cellulose digestion and total VFA compared with the NC. Both NaHCO3 and Na4P2O7 increased (P less than .05) the molar proportion of acetate to equal that of the PC. Tetrasodium pyrophosphate decreased (P less than .05) apparent starch digestion compared with the NC, but increased (P less than .05) the molar proportion of acetate. Compared with the NC, CaHPO4 and Na4P2O7 increased the quantity of microbial alpha-amino N in both diets. Soluble P was highly correlated with microbial protein synthesis in both the concentrate- and roughage-based diets (.92 and .90, respectively).

  1. Techniques for estimation of storm-runoff loads, volumes, and selected constituent concentrations in urban watersheds in the United States

    USGS Publications Warehouse

    Driver, Nancy E.; Tasker, Gary D.

    1990-01-01

    Urban planners and managers need information on the quantity of precipitation and the quality and quantity of run off in their cities and towns if they are to adequately plan for the effects of storm runoff from urban areas. As a result of this need, four sets of linear regression models were developed for estimating storm-runoff constituent loads, storm-runoff volumes, storm-runoff mean concentrations of constituents, and mean seasonal or mean annual constituent loads from physical, land-use, and climatic characteristics of urban watersheds in the United States. Thirty-four regression models of storm-runoff constituent loads and storm-runoff volumes were developed, and 31 models of storm-runoff mean concentrations were developed . Ten models of mean seasonal or mean annual constituent loads were developed by analyzing long-term storm-rainfall records using at-site linear regression models. Three statistically different regions, delineated on the basis of mean annual rainfall, were used to improve linear regression models where adequate data were available . Multiple regression analyses, including ordinary least squares and generalized least squares, were used to determine the optimum linear regression models . These models can be used to estimate storm-runoff constituent loads, storm-runoff volumes, storm-runoff mean concentrations of constituents, and mean seasonal or mean annual constituent loads at gaged and ungaged urban watersheds. The most significant explanatory variables in all linear regression models were total storm rainfall and total contributing drainage area. Impervious area, land-use, and mean annual climatic characteristics also were significant in some models. Models for estimating loads of dissolved solids, total nitrogen, and total ammonia plus organic nitrogen as nitrogen generally were the most accurate, whereas models for suspended solids were the least accurate. The most accurate models were those for application in the more arid Western

  2. Controlling the electron energy distribution function of electron beam generated plasmas with molecular gas concentration: II. Numerical modeling

    NASA Astrophysics Data System (ADS)

    Petrov, G. M.; Boris, D. R.; Petrova, Tz B.; Lock, E. H.; Fernsler, R. F.; Walton, S. G.

    2013-12-01

    In this work, the second in a series of two, a spatially averaged model of an electron beam generated Ar-N2 plasma is developed to identify the processes behind the measured influence of trace amounts of N2 on the development of the electron energy distribution function. The model is based on the numerical solution of the electron Boltzmann equation self-consistently coupled to a set of rate balance equations for electrons, argon and nitrogen species. Like the experiments, the calculations cover only the low-energy portion (<50 eV) of the electron energy distribution, and therefore a source term is added to the Boltzmann equation to represent ionization by the beam. Similarly, terms representing ambipolar diffusion along and across the magnetic field are added to allow for particle loss and electrostatic cooling from the ambipolar electric field. This work focuses on the changes introduced by adding a small admixture of nitrogen to an argon background. The model predictions for the electron energy distribution function, electron density and temperature are in good agreement with the experimentally measured data reported in part I, where it was found that the electron and ion energy distributions can be controlled by adjusting the fraction of nitrogen in the gas composition.

  3. Dipeptidyl peptidase-IV inhibitory peptides generated by tryptic hydrolysis of a whey protein concentrate rich in β-lactoglobulin.

    PubMed

    Silveira, Silvana T; Martínez-Maqueda, Daniel; Recio, Isidra; Hernández-Ledesma, Blanca

    2013-11-15

    Dipeptidyl peptidase-IV (DPP-IV) is a serine protease involved in the degradation and inactivation of incretin hormones that act by stimulating glucose-dependent insulin secretion after meal ingestion. DPP-IV inhibitors have emerged as new and promising oral agents for the treatment of type 2 diabetes. The purpose of this study was to investigate the potential of β-lactoglobulin as natural source of DPP-IV inhibitory peptides. A whey protein concentrate rich in β-lactoglobulin was hydrolysed with trypsin and fractionated using a chromatographic separation at semipreparative scale. Two of the six collected fractions showed notable DPP-IV inhibitory activity. These fractions were analysed by HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) to identify peptides responsible for the observed activity. The most potent fragment (IPAVF) corresponded to β-lactoglobulin f(78-82) which IC50 value was 44.7μM. The results suggest that peptides derived from β-lactoglobulin would be beneficial ingredients of foods against type 2 diabetes.

  4. Microfluidic system with integrated electroosmotic pumps, concentration gradient generator and fish cell line (RTgill-W1)--towards water toxicity testing.

    PubMed

    Glawdel, Tomasz; Elbuken, Caglar; Lee, Lucy E J; Ren, Carolyn L

    2009-11-21

    This study presents a microfluidic system that incorporates electroosmotic pumps, a concentration gradient generator and a fish cell line (rainbow trout gill) to perform toxicity testing on fish cells seeded in the system. The system consists of three mechanical components: (1) a toxicity testing chip containing a microfluidic gradient generator which creates a linear concentration distribution of toxicant in a cell test chamber, (2) an electroosmotic (EO) pump chip that controls the flow rate and operation of the toxicity chip, and (3) indirect reservoirs that connect the two chips allowing for the toxicant solution to be pumped separately from the electroosmotic pump solution. The flow rate and stability of the EO pumps was measured and tested by monitoring the gradient generator using fluorescence microscopy. Furthermore, a lethality test was performed with this system setup using a rainbow trout gill cell line (RTgill-W1) as the test cells and sodium dodecyl sulfate as a model toxicant. A gradient of sodium dodecyl sulfate, from 0 to 50 microg mL(-1), was applied for 1 hr to the attached cells, and the results were quantified using a Live/Dead cell assay. This work is a preliminary study on the application of EO pumps in a living cell assay, with the potential to use the pumps in portable water quality testing devices with RTgill-W1 cells as the biosensors. PMID:19865731

  5. Appraisal of heavy metal concentration in selected vegetables exposed to different degrees of pollution in Agra, India.

    PubMed

    Kumar, Suruchi

    2013-03-01

    The accumulation of air-borne heavy metals in edible parts of vegetables in the chosen areas of the city of Agra, India was investigated. Agra, with a population of 1.7 million, is a medium-sized Indian city where leafy green vegetables are received generally from the surrounding areas of about 50 km radius. Vegetables Basella alba (spinch, locally called palak), Trigonella foenumgraecum (fenugreek, locally called methi), and Coriandrum sativum (coriander, locally called dhania) from the various sites of Agra, India were tested for Pb, Cd, Cr, Ni, and Zn by atomic absorption spectroscopy in washed and unwashed vegetable. The results obtained from this analysis revealed higher concentrations of toxic elements in unwashed samples than the washed samples. Among unwashed samples it was found that concentration of heavy metals is more in areas of busy traffic or industry density. The levels of lead in all samples were found above the maximum permissible limit recommended by PFA for metals in vegetables. The study concludes that transportation and storage systems during marketing play a significant role in determining the contamination and deposition of heavy metal on vegetable surfaces specially of the leafy variety. PMID:22773079

  6. Urinary nickel concentrations and selected pregnancy outcomes in delivering women and their newborns among arctic populations of Norway and Russia.

    PubMed

    Odland, J Ø; Nieboer, E; Romanova, N; Thomassen, Y; Norseth, T; Lund, E

    1999-04-01

    The two objectives of this study were to compare urinary nickel excretion in pregnant women and their newborns living in the Murmansk and Arkhangelsk Counties of Russia with that in comparable Norwegian populations living in Finnmark and the city of Bergen and to assess the influence on pregnancy outcome of different risk variables, specifically urinary nickel concentrations and questionnaire-based anamnestic information. Life-style information and urine samples were collected from 50 consecutive mother-infant pairs from hospital delivery departments in three Russian and three Norwegian communities. Pregnancy outcomes were verified from medical records. Urinary nickel excretion was significantly higher in the Russian communities, independent of the presence of a nickel refinery as a local environmental source. The birth weight and mean body mass index of the newborn children (BMIC) were significantly lower (p < 0.001) in the Russian groups, with or without adjustment for gestational age. A multivariate linear regression analysis indicated that maternal urinary nickel concentration had no impact on birth weight. The maternal body mass index (BMI) and maternal height were positive explanatory variables; maternal urinary creatinine is suggested as a weak negative factor. Smoking was shown to be a strong negative predictor only in the Norwegian group among whom there was a significantly higher smoking frequency (p = 0.005). The significant contribution of a country factor in the predictive model is interpreted to indicate that a number of important risk factors for low birth weight were not identified. PMID:11529094

  7. Concentrations and estimated loads of nutrients, mercury, and polychlorinated biphenyls in selected tributaries to Lake Michigan, 2005-6

    USGS Publications Warehouse

    Westenbroek, Stephen M.

    2010-01-01

    The Lake Michigan Mass Balance Project (LMMBP) measured and modeled the concentrations of environmentally persistent contaminants in air, river and lake water, sediment, and fish and bird tissues in and around Lake Michigan for an 18-month period spanning 1994-95. Tributary loads were calculated as part of the LMMBP. The work described in this report was designed to provide updated concentration data and load estimates for 5 nutrients, total mercury, and total polychlorinated biphenyl (PCB) at 5 of the original 11 LMMBP sampling sites. Samples were collected at five Lake Michigan tributary monitoring sites during 2005 and 2006. Annual loads calculated for the 2005-6 sampling period are as much as 50 percent lower relative to the 1994-95 time period. Differences between the loads calculated for the two time periods are likely related to a combination of (1) biases introduced by a reduced level of sampling effort, (2) differences in hydrological characteristics, and (3) actual environmental change. Estimated annual total mercury loads during 2005-6 ranged from 51 kilograms per year (kg/yr) in the Fox River to 2.2 kg/yr in the Indiana Harbor and Ship Canal. Estimated annual total PCB loads during 2005-6 ranged from 132 kg/yr in the Fox River to 6.2 kg/yr in the Grand River.

  8. Relation of Landscape Position and Irrigation to Concentrations of Alachlor, Atrazine, and Selected Degradates in Regolith in Northeastern Nebraska

    USGS Publications Warehouse

    Verstraeten, Ingrid M.; Lewis, D.T.; McCallister, D.L.; Parkhurst, A.; Thurman, E.M.

    1996-01-01

    Concentrations of alachlor, its ethanesulfonic acid degradate, atrazine and its degradates, deethylatrazine and deisopropylatrazine, in the upper regolith and associated shallow aquifers were determined in relation to landscape position (floodplains, terraces, and uplands) and irrigation (nonirrigated and irrigated corn cropland) in 1992. Irrigated and nonirrigated sites were located on each landscape position. Samples were collected from three depths. Canonical discriminant and multivariate analyses were used to interpret data. Herbicides and their degradation products tended to be present in soils with high percent organic matter, low pH, and low sand content. Atrazine was present more frequently on the floodplain at all depths than the other compounds. Atrazine (maximum 17.5 ??g/kg) and ethanesulfonic acid (maximum 10 ??g/kg) were associated with landscape position, but not with irrigation. Alachlor (maximum 24 ??g/kg), deethylatrazine (maximum 1.5 ??g/kg), and deisopropylatrazine (maximum 3.5 ??g/kg) were not significantly associated with either landscape position or irrigation. Ground-water analytical results suggested that concentrations of these herbicides and degradates in ground water did not differ among landscape position or between irrigated and nonirrigated corn cropland.

  9. Mapping methane concentrations from a controlled release experiment using the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRISng)

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Frankenberg, C.; Roberts, D. A.; Aubrey, A. D.; Green, R. O.; Hulley, G. C.; Hook, S. J.

    2014-12-01

    Airborne imaging spectrometers like the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRISng) are well suited for monitoring local methane sources by covering large regions with the high spatial resolution necessary to resolve emissions. As part of a field campaign with controlled methane releases at the Rocky Mountain Oilfield Testing Center (RMOTC), a number of methane plumes were clearly visible at multiple flux rates and flight altitudes. Images of plumes appeared consistent with wind directions measured at ground stations and were present for fluxes as low as 14.2 cubic meters of methane per hour, equivalent to 0.09 kt/year. Direct comparison of results from AVIRISng and plume dispersion models is ongoing and will be used to assess the potential of constraining emission fluxes using AVIRISng. Methane plumes observed at RMOTC with the Hyperspectral Thermal Emission Spectrometer (HyTES) will also be presented. This controlled release experiment was used to determine the methane sensitivity of AVIRISng and inform sensor design for future imaging spectrometers that could constrain natural and anthropogenic methane emissions on local and regional scales. Imaging spectrometers permit direct attribution of emissions to individual point sources which is particularly useful given the large uncertainties associated with anthropogenic emissions, including industrial point source emissions and fugitive methane from the oil and gas industry. Figure caption: a. AVIRISng true color image indicating tube trailer (TT), meteorological tower (MT), and release point (RP). b. Prominent methane plume and measured enhancements for 70.8 cubic meters per hour methane flux is consistent with wind speed and direction (see arrow) measured by meteorological tower. A linear transect is shown in red and corresponds to enhancements shown in c. d. True color image showing release point (RP). e. Smaller methane plume for 14.2 cubic meters per hour flux. f. Methane

  10. Life Cycle Greenhouse Gas Emissions of Trough and Tower Concentrating Solar Power Electricity Generation: Systematic Review and Harmonization

    SciTech Connect

    Burkhardt, J. J.; Heath, G.; Cohen, E.

    2012-04-01

    In reviewing life cycle assessment (LCA) literature of utility-scale concentrating solar power (CSP) systems, this analysis focuses on reducing variability and clarifying the central tendency of published estimates of life cycle greenhouse gas (GHG) emissions through a meta-analytical process called harmonization. From 125 references reviewed, 10 produced 36 independent GHG emissions estimates passing screens for quality and relevance: 19 for parabolic trough (trough) technology and 17 for power tower (tower) technology. The interquartile range (IQR) of published estimates for troughs and towers were 83 and 20 grams of carbon dioxide equivalent per kilowatt-hour (g CO2-eq/kWh),1 respectively; median estimates were 26 and 38 g CO2-eq/kWh for trough and tower, respectively. Two levels of harmonization were applied. Light harmonization reduced variability in published estimates by using consistent values for key parameters pertaining to plant design and performance. The IQR and median were reduced by 87% and 17%, respectively, for troughs. For towers, the IQR and median decreased by 33% and 38%, respectively. Next, five trough LCAs reporting detailed life cycle inventories were identified. The variability and central tendency of their estimates are reduced by 91% and 81%, respectively, after light harmonization. By harmonizing these five estimates to consistent values for global warming intensities of materials and expanding system boundaries to consistently include electricity and auxiliary natural gas combustion, variability is reduced by an additional 32% while central tendency increases by 8%. These harmonized values provide useful starting points for policy makers in evaluating life cycle GHG emissions from CSP projects without the requirement to conduct a full LCA for each new project.

  11. Trends in concentrations of polychlorinated biphenyls in fish tissue from selected sites in the Delaware River basin in New Jersey, New York, and Pennsylvania, 1969-98

    USGS Publications Warehouse

    Riva-Murray, Karen; Brightbill, Robin A.; Bilger, Michael D.

    2003-01-01

    Trends in concentrations of polychlorinated biphenyls in fish tissue from selected sites in the Delaware River basin in New Jersey, New York, and Pennsylvania, 1969-98 by Karen Riva-Murray, Robin A. Brightbill, and Michael D. Bilger U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 01-4066 ABSTRACT Polychlorinated biphenyl (PCB) concentrations in fish tissue collected during the 1990's from selected sites in the Delaware River Basin were compared with concentrations in fish tissue collected during 1969-88. Data collected by State and Federal agencies on concentrations in whole-body common carp (Cyprinus carpio) and white sucker (Catostomus commersoni), and edible portions of American eel (Anguilla rostrata), smallmouth bass (Micropterus dolomieu), and channel catfish (Ictalurus punctatus) during 1969-98 were compiled to define temporal trends in concentrations of PCBs in fish tissue from selected segments of the Delaware River, Lehigh River, Schuylkill River, and Brandywine Creek. The Delaware River in the vicinity of Trenton, New Jersey and Yardley, Pennsylvania (above the tidal influence) had the largest long-term data set among the sites considered for this study and was the only site with sufficient data for statistical analysis. A general pattern of decline in PCB concentrations during 1969-98 was apparent for this river segment. PCB concentrations in whole-body white sucker from this lower Delaware River segment declined during 1969-98 from a highest concentration of 7 micrograms per gram (?g/g, wet weight) in a sample collected during 1972 to 0.26 ?g/g (wet weight) in a sample collected during 1998. PCB concentration was negatively correlated with year (Spearman rank correlation -0.46, p < 0.08, n = 15); especially after removal of a sample from 1977 with an unusually low concentration (Spearman rank correlation -0.53, p = 0.05, n = 14). PCB concentrations in edible flesh of American eel declined during 1975-95, from a highest concentration of 3

  12. Land use, organochlorine compound concentrations, and trends in benthic-invertebrate communities in selected stream basins in Chester County, Pennsylvania

    USGS Publications Warehouse

    Hardy, Mark A.; Wetzel, Kim L.; Moore, Craig R.

    1995-01-01

    Land use was analyzed for the drainage areas of 26 stream sites in Chester County, Pa., that cover a total area of 227 square miles or about 30 percent of the country. The most significant land-use changes during 1967-87 were decreased agricultural land use, increased residential land use, and increased commercial and industrial land use. Bulk samples of stream-bottom materials were collected at 42 sites in the study area from October 1985 through November 1987 and analyzed for content of organochlorine pesticides and polychlorinated biphenyls (PCB's). Organochlorine compounds and (or) PCB's were detected in streambed materials collected at 40 of the 42 sites sampled. The most enriched compounds (greater than 15 micrograms per kilogram) were PCB's, chlordane, and DDT plus its breakdown products. Data suggest that chlordane residues are closely associated with residential land use. PCB residues are closely associated with industrial and commercial land use. Cores of labeled sediments from the site of Icedale Lake, a drained reservoir on the West Branch Brandywine Creek, indicate that DDT was the first organochlorine pesticide to enter the Brandywine Creek; concentrations peaked in the late 1940's and early 1950's. As DDT influx subsequently decreased, influxes of chlordane and dieldrin increased and peaked in the mind-1960's, before the Chester County biological monitoring program. Influx of all pesticides appears to have decreased significantly since the 1960's. Contingency analyses showed that the relation between the Kendall slope estimator for trend and the increases in residential land use of 12 percent or greater were significant at the 95-percent confidence level. The contingency tables also showed that the relation between diversity indices of less than 2.25 and organochlorine-compound concentrations greater than 45 micrograms per kilogram was significant at the 95-percent confidence level.

  13. PCDD, PCDF, PCB and PBDE concentrations in breast milk of mothers residing in selected areas of Slovakia.

    PubMed

    Chovancová, Jana; Čonka, Kamil; Kočan, Anton; Sejáková, Zuzana Stachová

    2011-05-01

    The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and polybrominated diphenylethers (PBDEs) in 33 breast milk samples collected in 2006-2007 from primipara mothers close to four industrial areas of Slovak Republic were determined. The total PCDDs/PCDFs and dl-PCBs expressed as TEQ based on WHO TEFs 1998 in breast milk samples varied from 5.0 to 51.8 pg g(-1) fat (median: 13.1 pg g(-1) fat; mean: 18.0 pg g(-1) fat). The measurements of seven PBDE congeners (IUPAC No. 28, 47, 99, 100, 153, 154, and 183) were performed for the first time in human milk from Slovakia. PBDE levels ranged between 0.22 and 1.62 ng g(-1) fat, with median and mean value of 0.43 ng g(-1) fat and 0.57 ng g(-1) fat respectively. No statistically significant differences were observed between studied areas in total PBDE concentrations. Furthermore, this study presents first results concerning the daily intake (DI) of PCDDs/PCDFs and dioxin-like compounds for the most vulnerable breast-fed infant population in Slovakia. The total PCDD/PCDF and dl-PCB DI for an infant during the first 2 months of life was estimated in a range from 14.4 to 230 pg TEQ kg(-1)b.w., with a median value of 58.9 pg TEQ kg(-1)b.w.. The DI values substantially exceeded the tolerable daily intake (TDI) 1-4 pg TEQ kg(-1)b.w. recommended by WHO. The dietary infant intake concerning PBDEs was estimated to be between 0.69 and 7.1 ng kg(-1)b.w.d(-1), with median value of 1.7 ng kg(-1)b.w.d(-1).

  14. Developing "Personality" Taxonomies: Metatheoretical and Methodological Rationales Underlying Selection Approaches, Methods of Data Generation and Reduction Principles.

    PubMed

    Uher, Jana

    2015-12-01

    Taxonomic "personality" models are widely used in research and applied fields. This article applies the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) to scrutinise the three methodological steps that are required for developing comprehensive "personality" taxonomies: 1) the approaches used to select the phenomena and events to be studied, 2) the methods used to generate data about the selected phenomena and events and 3) the reduction principles used to extract the "most important" individual-specific variations for constructing "personality" taxonomies. Analyses of some currently popular taxonomies reveal frequent mismatches between the researchers' explicit and implicit metatheories about "personality" and the abilities of previous methodologies to capture the particular kinds of phenomena toward which they are targeted. Serious deficiencies that preclude scientific quantifications are identified in standardised questionnaires, psychology's established standard method of investigation. These mismatches and deficiencies derive from the lack of an explicit formulation and critical reflection on the philosophical and metatheoretical assumptions being made by scientists and from the established practice of radically matching the methodological tools to researchers' preconceived ideas and to pre-existing statistical theories rather than to the particular phenomena and individuals under study. These findings raise serious doubts about the ability of previous taxonomies to appropriately and comprehensively reflect the phenomena towards which they are targeted and the structures of individual-specificity occurring in them. The article elaborates and illustrates with empirical examples methodological principles that allow researchers to appropriately meet the metatheoretical requirements and that are suitable for comprehensively exploring individuals' "personality".

  15. Concentrations and geographical variations of selected toxic elements in meat from semi-domesticated reindeer (Rangifer tarandus tarandus L.) in mid- and northern Norway: evaluation of risk assessment.

    PubMed

    Hassan, Ammar Ali; Brustad, Magritt; Sandanger, Torkjel M

    2012-05-01

    Meat samples (n = 100) from semi-domesticated reindeer (Rangifer tarandus tarandus L.) were randomly collected from 10 grazing districts distributed over four Norwegian counties in 2008 and 2009. The main aim was to study concentrations and geographical variations in selected toxic elements; cadmium (Cd), lead (Pb), arsenic (As), copper (Cu), nickel (Ni) and vanadium (V) in order to assess the risk associated with reindeer meat consumption. Sample solutions were analysed using an inductively coupled plasma high resolution mass spectrometer (ICP-HRMS), whereas analysis of variance (ANOVA) was used for statistical analyses. Geographical variations in element concentrations were revealed, with As and Cd demonstrating the largest geographical differences. No clear geographical gradient was observed except for the east-west downward gradient for As. The As concentrations were highest in the vicinity of the Russian border, and only Cd was shown to increase with age (p < 0.05). Sex had no significant effect on the concentration of the studied elements. The concentrations of all the studied elements in reindeer meat were generally low and considerably below the maximum levels (ML) available for toxic elements set by the European Commission (EC). Thus, reindeer meat is not likely to be a significant contributor to the human body burden of toxic elements.

  16. [Evaluation test of cadmium concentration influence on selected lipid metabolism parameters in smokers with stable coronary artery disease scheduled for coronary artery bypass grafting (CABG)].

    PubMed

    Kleszczewska, Ewa; Lisowski, Piotr; Kleszczewski, Tomasz; Adamczuk, Anna; Trzciński, Robert

    2005-01-01

    The influence of cadium from cigarette intoxication on selected lipid metabolism parameters in smokers with stable coronary artery disease scheduled for coronary artery bypass grafting (CABG) was studied. It has been shown that concentration of cadmium leads to an increase in the lipid peroxidation and changes in the lipid metabolism. In our study, there was a significant higher cadmium concentration in smokers with stable angina pectoris (20.90+/-0.18) compared to stable angina pectoris non-smokers (7.71 +/-0,45), p<0.0001. We have not found correlations between cadmium concentration in smokers and non-smokers with stable angina pectoris patients and total cholesterol, LDL, HDL, and triglicerydes concentrations. Total cholesterol, LDL, HDL and TG concentrations in smokers scheduled for CABG were respectively: 221.60+/-10.26 mg/dl; 148.40+/-8.71 mg/dl; 41.16+/-2.12 mg/dl, 159.10+/-14.49 mg/dl. All of these lipid parameters in stable angina pectoris smokers did not differ significantly from non-smokers.

  17. Microfluidic device generating stable concentration gradients for long term cell culture: application to Wnt3a regulation of β-catenin signaling.

    PubMed

    Cimetta, Elisa; Cannizzaro, Christopher; James, Richard; Biechele, Travis; Moon, Randall T; Elvassore, Nicola; Vunjak-Novakovic, Gordana

    2010-12-01

    In developing tissues, proteins and signaling molecules present themselves in the form of concentration gradients, which determine the fate specification and behavior of the sensing cells. To mimic these conditions in vitro, we developed a microfluidic device designed to generate stable concentration gradients at low hydrodynamic shear and allowing long term culture of adhering cells. The gradient forms in a culture space between two parallel laminar flow streams of culture medium at two different concentrations of a given morphogen. The exact algorithm for defining the concentration gradients was established with the aid of mathematical modeling of flow and mass transport. Wnt3a regulation of β-catenin signaling was chosen as a case study. The highly conserved Wnt-activated β-catenin pathway plays major roles in embryonic development, stem cell proliferation and differentiation. Wnt3a stimulates the activity of β-catenin pathway, leading to translocation of β-catenin to the nucleus where it activates a series of target genes. We cultured A375 cells stably expressing a Wnt/β-catenin reporter driving the expression of Venus, pBARVS, inside the microfluidic device. The extent to which the β-catenin pathway was activated in response to a gradient of Wnt3a was assessed in real time using the BARVS reporter gene. On a single cell level, the β-catenin signaling was proportionate to the concentration gradient of Wnt3a; we thus propose that the modulation of Wnt3a gradients in real time can provide new insights into the dynamics of β-catenin pathway, under conditions that replicate some aspects of the actual cell-tissue milieu. Our device thus offers a highly controllable platform for exploring the effects of concentration gradients on cultured cells. PMID:20936235

  18. Well-Known Mediators of Selective Oxidation with Unknown Electronic Structure: Metal-Free Generation and EPR Study of Imide-N-oxyl Radicals.

    PubMed

    Krylov, Igor B; Kompanets, Mykhailo O; Novikova, Katerina V; Opeida, Iosip O; Kushch, Olga V; Shelimov, Boris N; Nikishin, Gennady I; Levitsky, Dmitri O; Terent'ev, Alexander O

    2016-01-14

    Nitroxyl radicals are widely used in chemistry, materials sciences, and biology. Imide-N-oxyl radicals are subclass of unique nitroxyl radicals that proved to be useful catalysts and mediators of selective oxidation and CH-functionalization. An efficient metal-free method was developed for the generation of imide-N-oxyl radicals from N-hydroxyimides at room temperature by the reaction with (diacetoxyiodo)benzene. The method allows for the production of high concentrations of free radicals and provides high resolution of their EPR spectra exhibiting the superhyperfine structure from benzene ring protons distant from the radical center. An analysis of the spectra shows that, regardless of the electronic effects of the substituents in the benzene ring, the superhyperfine coupling constant of an unpaired electron with the distant protons at positions 4 and 5 of the aromatic system is substantially greater than that with the protons at positions 3 and 6 that are closer to the N-oxyl radical center. This is indicative of an unusual character of the spin density distribution of the unpaired electron in substituted phthalimide-N-oxyl radicals. Understanding of the nature of the electron density distribution in imide-N-oxyl radicals may be useful for the development of commercial mediators of oxidation based on N-hydroxyimides.

  19. Selective hydride generation- cryotrapping- ICP-MS for arsenic speciation analysis at picogram levels: analysis of river and sea water reference materials and human bladder epithelial cells

    PubMed Central

    Matoušek, Tomáš; Currier, Jenna M.; Trojánková, Nikola; Saunders, R. Jesse; Ishida, María C.; González-Horta, Carmen; Musil, Stanislav; Mester, Zoltán; Stýblo, Miroslav; Dědina, Jiří

    2013-01-01

    An ultra sensitive method for arsenic (As) speciation analysis based on selective hydride generation (HG) with preconcentration by cryotrapping (CT) and inductively coupled plasma- mass spectrometry (ICP-MS) detection is presented. Determination of valence of the As species is performed by selective HG without prereduction (trivalent species only) or with L-cysteine prereduction (sum of tri- and pentavalent species). Methylated species are resolved on the basis of thermal desorption of formed methyl substituted arsines after collection at −196°C. Limits of detection of 3.4, 0.04, 0.14 and 0.10 pg mL−1 (ppt) were achieved for inorganic As, mono-, di- and trimethylated species, respectively, from a 500 μL sample. Speciation analysis of river water (NRC SLRS-4 and SLRS-5) and sea water (NRC CASS-4, CASS-5 and NASS-5) reference materials certified to contain 0.4 to 1.3 ng mL−1 total As was performed. The concentrations of methylated As species in tens of pg mL−1 range obtained by HG-CT-ICP-MS systems in three laboratories were in excellent agreement and compared well with results of HG-CT-atomic absorption spectrometry and anion exchange liquid chromatography- ICP-MS; sums of detected species agreed well with the certified total As content. HG-CT-ICP-MS method was successfully used for analysis of microsamples of exfoliated bladder epithelial cells isolated from human urine. Here, samples of lysates of 25 to 550 thousand cells contained typically tens pg up to ng of iAs species and from single to hundreds pg of methylated species, well within detection power of the presented method. A significant portion of As in the cells was found in the form of the highly toxic trivalent species. PMID:24014931

  20. Particle size distributions, size concentration relationships, and adherence to hands of selected geologic media derived from mining, smelting, and quarrying activities.

    PubMed

    Bergstrom, Carolyn; Shirai, Jeffry; Kissel, John

    2011-09-15

    Hand-to-mouth activity, especially in children, is a potentially significant pathway of exposure to soil contaminants. Hand-mouthing behavior is of particular concern in areas impacted by mining, smelting, and quarrying activities as these activities may lead to elevated levels of heavy metals in soil. In order to estimate potential exposures to contaminated geologic media attributable to hand-to-mouth contact, it is useful to characterize adherence of those media to skin, as contaminant concentrations in adhered media may differ greatly from unfractionated, whole media concentrations. Such an investigation has been undertaken to aid estimation of exposures to arsenic, cadmium, lead, and zinc in nine different geologic media collected in the Pacific Northwest region of the United States. After establishing the particle size distribution of each medium (fractions <63 μm, 63-150 μm, 150-250 μm, and 250 μm-2mm were determined) and target elemental concentrations within each particle size fraction, an active handling protocol involving six volunteers was conducted. Wet media always adhered to a greater extent than dry media and adhered media generally had higher elemental concentrations than bulk media. Regression analyses suggest smaller particle fractions may have higher elemental concentrations. Results of application of a maximum likelihood estimation technique generally indicate that handling of dry media leads to preferential adherence of smaller particle sizes, while handling of wet media does not. Because adhered material can differ greatly in particle size distribution from that found in bulk material, use of bulk concentrations in exposure calculations may lead to poor estimation of actual exposures. Since lead has historically been a metal of particular concern, EPA's Integrated Exposure Uptake Biokinetic (IEUBK) Model was used to examine the potential consequences of evaluating ingestion of the selected media assuming concentrations in adhering versus

  1. Particle size distributions, size concentration relationships, and adherence to hands of selected geologic media derived from mining, smelting, and quarrying activities.

    PubMed

    Bergstrom, Carolyn; Shirai, Jeffry; Kissel, John

    2011-09-15

    Hand-to-mouth activity, especially in children, is a potentially significant pathway of exposure to soil contaminants. Hand-mouthing behavior is of particular concern in areas impacted by mining, smelting, and quarrying activities as these activities may lead to elevated levels of heavy metals in soil. In order to estimate potential exposures to contaminated geologic media attributable to hand-to-mouth contact, it is useful to characterize adherence of those media to skin, as contaminant concentrations in adhered media may differ greatly from unfractionated, whole media concentrations. Such an investigation has been undertaken to aid estimation of exposures to arsenic, cadmium, lead, and zinc in nine different geologic media collected in the Pacific Northwest region of the United States. After establishing the particle size distribution of each medium (fractions <63 μm, 63-150 μm, 150-250 μm, and 250 μm-2mm were determined) and target elemental concentrations within each particle size fraction, an active handling protocol involving six volunteers was conducted. Wet media always adhered to a greater extent than dry media and adhered media generally had higher elemental concentrations than bulk media. Regression analyses suggest smaller particle fractions may have higher elemental concentrations. Results of application of a maximum likelihood estimation technique generally indicate that handling of dry media leads to preferential adherence of smaller particle sizes, while handling of wet media does not. Because adhered material can differ greatly in particle size distribution from that found in bulk material, use of bulk concentrations in exposure calculations may lead to poor estimation of actual exposures. Since lead has historically been a metal of particular concern, EPA's Integrated Exposure Uptake Biokinetic (IEUBK) Model was used to examine the potential consequences of evaluating ingestion of the selected media assuming concentrations in adhering versus

  2. A new portable generator to dynamically produce SI-traceable reference gas mixtures for VOCs and water vapour at atmospheric concentration

    NASA Astrophysics Data System (ADS)

    Guillevic, Myriam; Pascale, Céline; Ackermann, Andreas; Leuenberger, Daiana; Niederhauser, Bernhard

    2016-04-01

    In the framework of the KEY-VOCs and AtmoChem-ECV projects, we are currently developing new facilities to dynamically generate reference gas mixtures for a variety of reactive compounds, at concentrations measured in the atmosphere and in a SI-traceable way (i.e. the amount of substance fraction in mole per mole is traceable to SI-units). Here we present the realisation of such standards for water vapour in the range 1-10 μmol/mol and for volatile organic compounds (VOCs) such as limonene, alpha-pinene, MVK, MEK, in the nmol/mol range. The matrix gas can be nitrogen or synthetic air. Further development in gas purification techniques could make possible to use purified atmospheric air as carrier gas. The method is based on permeation and dynamic dilution: one permeator containing a pure substance (either water, limonene, MVK, MEK or α-pinene) is kept into a permeation chamber with a constant gas flow. The mass loss is precisely calibrated using a magnetic suspension balance. The carrier gas is purified beforehand from the compounds of interest to the required level, using commercially available purification cartridges. This primary mixture is then diluted to reach the required amount of substance fraction. All flows are piloted by mass flow controllers which makes the production process flexible and easily adaptable to generate the required concentration. All parts in contact with the gas mixture are passivated using coated surfaces, to reduce adsorption/desorption processes as much as possible. Two setups are currently developed: one already built and fixed in our laboratory in Bern as well as a portable generator that is still under construction and that could be used anywhere in the field. The permeation chamber of the portable generator has multiple individual cells allowing the generation of mixtures up to 5 different components if needed. Moreover the presented technique can be adapted and applied to a large variety of molecules (e.g., NO2, BTEX, CFCs

  3. Trace element, semivolatile organic, and chlorinated organic compound concentrations in bed sediments of selected streams at Fort Gordon, Georgia, February-April 2010

    USGS Publications Warehouse

    Thomas, Lashun K.; Journey, Celeste A.; Stringfield, Whitney J.; Clark, Jimmy M.; Bradley, Paul M.; Wellborn, John B.; Ratliff, Hagan; Abrahamsen, Thomas A.

    2011-01-01

    A spatial survey of streams was conducted from February to April 2010 to assess the concentrations of major ions, selected trace elements, semivolatile organic compounds, organochlorine pesticides, and polychlorinated biphenyls associated with the bed sediments of surface waters at Fort Gordon military installation near Augusta, Georgia. This investigation expanded a previous study conducted in May 1998 by the U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, that evaluated the streambed sediment quality of selected surface waters at Fort Gordon. The data presented in this report are intended to help evaluate bed sediment quality in relation to guidelines for the protection of aquatic life, and identify temporal trends in trace elements and semivolatile organic compound concentrations at streambed sites previously sampled. Concentrations of 34 major ions and trace elements and 102 semivolatile organic, organochlorine pesticide, and polychlorinated biphenyl compounds were determined in the fine-grained fraction of bed sediment samples collected from 13 of the original 29 sites in the previous study, and 22 additional sites at Fort Gordon. Three of the sites were considered reference sites as they were presumed to be located away from potential sources of contaminants and were selected to represent surface waters flowing onto the fort, and the remaining 32 nonreference sites were presumed to be located within the contamination area at the fort. Temporal trends in trace elements and semivolatile organic compound concentrations also were evaluated at 13 of the 32 nonreference sites to provide an assessment of the variability in the number of detections and concentrations of constituents in bed sediment associated with potential sources, accumulation, and attenuation processes. Major ion and trace element concentrations in fine-grained bed

  4. Hybrid SnO₂/TiO₂ Nanocomposites for Selective Detection of Ultra-Low Hydrogen Sulfide Concentrations in Complex Backgrounds.

    PubMed

    Larin, Alexander; Womble, Phillip C; Dobrokhotov, Vladimir

    2016-01-01

    In this paper, we present a chemiresistive metal oxide (MOX) sensor for detection of hydrogen sulfide. Compared to the previous reports, the overall sensor performance was improved in multiple characteristics, including: sensitivity, selectivity, stability, activation time, response time, recovery time, and activation temperature. The superior sensor performance was attributed to the utilization of hybrid SnO₂/TiO₂ oxides as interactive catalytic layers deposited using a magnetron radio frequency (RF) sputtering technique. The unique advantage of the RF sputtering for sensor fabrication is the ability to create ultra-thin films with precise control of geometry, morphology and chemical composition of the product of synthesis. Chemiresistive films down to several nanometers can be fabricated as sensing elements. The RF sputtering technique was found to be very robust for bilayer and multilayer oxide structure fabrication. The geometry, morphology, chemical composition and electronic structure of interactive layers were evaluated in relation to their gas sensing performance, using scanning electron microscopy (SEM), X-ray diffraction technique (XRD), atomic force microscopy (AFM), Energy Dispersive X-ray Spectroscopy (EDAX), UV visible spectroscopy, and Kelvin probe measurements. A sensor based on multilayer SnO₂/TiO₂ catalytic layer with 10% vol. content of TiO₂ demonstrated the best gas sensing performance in all characteristics. Based on the pattern relating material's characteristics to gas sensing performance, the optimization strategy for hydrogen sulfide sensor fabrication was suggested. PMID:27618900

  5. Hybrid SnO₂/TiO₂ Nanocomposites for Selective Detection of Ultra-Low Hydrogen Sulfide Concentrations in Complex Backgrounds.

    PubMed

    Larin, Alexander; Womble, Phillip C; Dobrokhotov, Vladimir

    2016-08-27

    In this paper, we present a chemiresistive metal oxide (MOX) sensor for detection of hydrogen sulfide. Compared to the previous reports, the overall sensor performance was improved in multiple characteristics, including: sensitivity, selectivity, stability, activation time, response time, recovery time, and activation temperature. The superior sensor performance was attributed to the utilization of hybrid SnO₂/TiO₂ oxides as interactive catalytic layers deposited using a magnetron radio frequency (RF) sputtering technique. The unique advantage of the RF sputtering for sensor fabrication is the ability to create ultra-thin films with precise control of geometry, morphology and chemical composition of the product of synthesis. Chemiresistive films down to several nanometers can be fabricated as sensing elements. The RF sputtering technique was found to be very robust for bilayer and multilayer oxide structure fabrication. The geometry, morphology, chemical composition and electronic structure of interactive layers were evaluated in relation to their gas sensing performance, using scanning electron microscopy (SEM), X-ray diffraction technique (XRD), atomic force microscopy (AFM), Energy Dispersive X-ray Spectroscopy (EDAX), UV visible spectroscopy, and Kelvin probe measurements. A sensor based on multilayer SnO₂/TiO₂ catalytic layer with 10% vol. content of TiO₂ demonstrated the best gas sensing performance in all characteristics. Based on the pattern relating material's characteristics to gas sensing performance, the optimization strategy for hydrogen sulfide sensor fabrication was suggested.

  6. Selective fermentation of pitted dates by S. cerevisiae for the production of concentrated fructose syrups and ethanol

    NASA Astrophysics Data System (ADS)

    Dharma Putra, Meilana; Abasaeed, Ahmed E.; Zeinelabdeen, Mohamed A.; Gaily, Mohamed H.; Sulieman, Ashraf K.

    2014-04-01

    About half of worldwide production of dates is unconsumed. Dates contain over 75 % reduced sugars (mostly glucose and fructose with nearly equal amount). Compared to the commercial Saccharomyces cerevisiae wild strain, the strains ATCC 36858 and 36859 could produce high concentration fructose syrups. The fructose fractions obtained were 95.9 and 97.4% for ATCC 36858 and 86.5 and 91.4% for ATCC 36859 at 30 and 33°C, respectively. Fructose yields higher than 90% were obtained using ATCC 36858 compared to those obtained using ATCC 36859 which were 87.3 and 66.1% at 30 and 33°C, respectively. The ethanol yield using ATCC 36858 was higher than that using ATCC 36859 by 16 and 9% at 30 and 33°C, respectively. Through this finding, the production of fructose and ethanol from date extract is a promising process. Moreover, the fructose fractions obtained here (about 90%) are much higher than those obtained with the commercial process, i.e. 55 % fructose syrups.

  7. Whole blood lead concentration and erythrocyte delta-aminolevul