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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.

  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. Spectral Selectivity Applied To Hybrid Concentration Systems

    NASA Astrophysics Data System (ADS)

    Hamdy, M. A.; Luttmann, F.; Osborn, D. E.; Jacobson, M. R.; MacLeod, H. A.

    1985-12-01

    The efficiency of conversion of concentrated solar energy can be improved by separating the solar spectrum into portions matched to specific photoquantum processes and the balance used for photothermal conversion. The basic approaches of spectrally selective beam splitters are presented. A detailed simulation analysis using TRNSYS is developed for a spectrally selective hybrid photovoltaic/photothermal concentrating system. The analysis shows definite benefits to a spectrally selective approach.

  4. Concentrated solar power generation using solar receivers

    DOEpatents

    Anderson, Bruce N.; Treece, William Dean; Brown, Dan; Bennhold, Florian; Hilgert, Christoph

    2017-08-08

    Inventive concentrated solar power systems using solar receivers, and related devices and methods, are generally described. Low pressure solar receivers are provided that function to convert solar radiation energy to thermal energy of a working fluid, e.g., a working fluid of a power generation or thermal storage system. In some embodiments, low pressure solar receivers are provided herein that are useful in conjunction with gas turbine based power generation systems.

  5. 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.

  6. Informing Selection of Nanomaterial Concentrations for ...

    EPA Pesticide Factsheets

    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 concentrations measured in air in manufacturing and R&D labs to identify input levels for estimating ENM mass retained in the human lung using the Multiple-Path Particle Dosimetry (MPPD) model. Model input parameters were individually varied to estimate alveolar mass retained for different particle sizes (5-1000 nm), aerosol concentrations (0.1, 1 mg/m3), aspect ratios (2, 4, 10, 167), and exposure durations (24 hours and a working lifetime). The calculated lung surface concentrations were then converted to in vitro solution concentrations. Modeled alveolar mass retained after 24 hours is most affected by activity level and aerosol concentration. Alveolar retention for Ag and TiO2 nanoparticles and CNTs for a working lifetime (45 years) exposure duration is similar to high-end concentrations (~ 30-400 μg/mL) typical of in vitro testing reported in the literature. Analyses performed are generally applicable to provide ENM testing concentrations for in vitro hazard screening studies though further research is needed to improve the approach. Understanding the relationship between potential real-world exposures and in vitro test concentrations will facilitate interpretation of toxicological results

  7. 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.

  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. 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.

  10. Intracerebral source generators characterizing concentrative meditation.

    PubMed

    Lavallee, Christina F; Hunter, Mathew D; Persinger, Michael A

    2011-05-01

    Previous researchers have studied meditation practices as a means to understand consciousness as well as altered states of consciousness. Various meditation techniques, such as Transcendental Meditation (TM) and Qigong, have been explored with source localization tools; however, the concentrative meditation technique has yet to be fully studied in this manner. The current study demonstrates findings, which outline differential activation in a self-referential default network during meditation in participants who espouse themselves as regular concentrative meditation practitioners, as well as comparisons with a control group practicing a modified version of the relaxation response. The results are compared with other putative experimental findings employing other meditation techniques, and the findings outlined in the current study are discussed with respect to changes in perceptual awareness often reported by meditators.

  11. Diversity versus concentration in antipsychotic drug selection.

    PubMed

    Leslie, Douglas L; Rosenheck, Robert A

    2008-09-01

    It is unknown to what extent providers utilize the full range of available antipsychotic agents, or tend to prescribe just a few with which they are familiar. This study uses the Herfindahl index to measure the degree to which antipsychotic prescribing is diverse or concentrated within medical centers in the Department of Veterans Affairs. Patients with schizophrenia who received prescriptions for antipsychotic medications from the Department of Veterans Affairs in fiscal year 2005 were identified. For each facility, the proportion of prescriptions that were written for each antipsychotic medication was computed. The Herfindahl index, which is defined as the sum of the square of the proportionate shares of each medication (i.e., 50% squared = 0.25), was computed for each facility, and its distribution across facilities was examined. We identified 785,485 prescriptions for antipsychotic medications across 76,787 patients within 128 facilities. With 7 drugs to choose from (first-generation antipsychotics were not differentiated as separate drugs), the Herfindahl could range from 0.14 (if the drugs were prescribed equally) to 1 (if only 1 drug was prescribed to all patients). The Herfindahl averaged 0.20 to 0.21 and ranged from 0.16 to 0.31 across facilities. The Herfindahl index is a useful metric for describing the degree to which providers use a range of antipsychotic medications in treating patients with schizophrenia and suggests that VA facilities use a diversity of agents, thus taking advantage of the potentially unique drug-patient matches. The extent to which providers tailor their choice of antipsychotic medication to the particular characteristics of the patient may lead to better quality of care. The fact that providers do use a range of antipsychotic medications suggests that formulary policies should not reduce access to these drugs. Further research is needed to construct physician-level measures of prescribing diversity and to examine whether clinical

  12. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Selection of antibiotic resistance at very low antibiotic concentrations

    PubMed Central

    2014-01-01

    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. PMID:24694026

  14. 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.

  15. Market concentration and marketing power among electricity generators in Texas

    SciTech Connect

    Zarnikau, J.; Lam, A.

    1998-11-01

    Policy initiatives designed to foster competition among electricity generators in Texas face a special challenge due to the relative isolation of that system. This isolation contributes to high levels of market concentration and market power that could hinder the development of a truly competitive market. This paper examines market concentration and market power in the ERCOT market for electricity generation by calculating the Herfindahl-Hirschman index (HHI) under various assumptions to gauge the degree of market concentration among generators in ERCOT. In addition, some ongoing studies of market power in ERCOT are discussed. The distinction between market concentration and market power is highlighted.

  16. Selective evolutionary generation systems: Theory and applications

    NASA Astrophysics Data System (ADS)

    Menezes, Amor A.

    This dissertation is devoted to the problem of behavior design, which is a generalization of the standard global optimization problem: instead of generating the optimizer, the generalization produces, on the space of candidate optimizers, a probability density function referred to as the behavior. The generalization depends on a parameter, the level of selectivity, such that as this parameter tends to infinity, the behavior becomes a delta function at the location of the global optimizer. The motivation for this generalization is that traditional off-line global optimization is non-resilient and non-opportunistic. That is, traditional global optimization is unresponsive to perturbations of the objective function. On-line optimization methods that are more resilient and opportunistic than their off-line counterparts typically consist of the computationally expensive sequential repetition of off-line techniques. A novel approach to inexpensive resilience and opportunism is to utilize the theory of Selective Evolutionary Generation Systems (SECS), which sequentially and probabilistically selects a candidate optimizer based on the ratio of the fitness values of two candidates and the level of selectivity. Using time-homogeneous, irreducible, ergodic Markov chains to model a sequence of local, and hence inexpensive, dynamic transitions, this dissertation proves that such transitions result in behavior that is called rational; such behavior is desirable because it can lead to both efficient search for an optimizer as well as resilient and opportunistic behavior. The dissertation also identifies system-theoretic properties of the proposed scheme, including equilibria, their stability and their optimality. Moreover, this dissertation demonstrates that the canonical genetic algorithm with fitness proportional selection and the (1+1) evolutionary strategy are particular cases of the scheme. Applications in three areas illustrate the versatility of the SECS theory: flight

  17. Microstructure devices generation by selective laser melting

    NASA Astrophysics Data System (ADS)

    Brandner, Juergen J.; Hansjosten, Edgar; Anurjew, Eugen; Pfleging, Wilhelm; Schubert, Klaus

    2007-02-01

    Selective Laser Melting (SLM) is a generative manufacturing procedure mainly known for the application with metal powders. From these, metallic structures are produced in a layer-by-layer way. This layer-related procedure is comparable to the stereolithographic manufacturing of polymer devices. On a base plate, a thin layer of metal powder is spread. The powder is locally completely melted by the application of a focused laser beam. The base plate is then lowered by a value defined by the thickness of the metal layer, metal powder is spread again, and the local melting process is re-initiated. The complete procedure is continued as described, until the device is manufactured in the defined way. Commercially available metal powder can be used as base material. In principle, the SLM process should be suitable for the generation of metallic microstructures. The main precondition for the generation of microstructures by SLM is that the spatial resolution of the laser focus is small and precise enough to generate microstructure walls of around 100μm thickness in a reproducible way by melting metal powder. The walls should be gas- and leak-tight. In this publication, experimental results of the generation of metallic microstructure devices by SLM will be given. The process will be described in details. Process parameters for the generation of stainless steel devices having wall thicknesses in the range of about 100μm will be given. Examples for microstructure devices made by SLM will be shown. The devices can be manufactured in a reproducible way. Moreover, very first preliminary results on the use of ceramic powder as base material will be presented.

  18. 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.

  19. Generating Hydrogen through Water Electrolysis using Concentrator Photovoltaics

    SciTech Connect

    McConnell, R.; Thompson, J.

    2005-01-01

    Hydrogen can be an important element in reducing global climate change if the feedstock and process to produce the hydrogen are carbon free. Using nuclear energy to power a high temperature water electrolysis process meets these constraints while another uses heat and electricity from solar electric concentrators. Nuclear researchers have estimated the cost of hydrogen generated in this fashion and we will compare their estimates with those we have made for generating hydrogen using electricity and waste heat from a dish concentrator photovoltaic system. The conclusion is that the costs are comparable and low enough to compete with gasoline costs in the not too distant future.

  20. 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.

  1. The 1st generation low cost point focus solar concentrator

    NASA Technical Reports Server (NTRS)

    Zimmerman, J.

    1980-01-01

    A point focus solar concentrator that, given a high volume of production, will optimize the ratio of performance to cost is considered. The concentrator design approach has evolved by a systematic process of examining the operating requirements particular to the solar application, minimizing material content through detail structural design and structurally efficient subsystem features, and utilizing materials and processes compatible with high volume production techniques. The design approach, the rationale for the configuration and subsystem selections, and the development status are described.

  2. Integrated microfluidic system with simultaneous emulsion generation and concentration.

    PubMed

    Koppula, Karuna S; Fan, Rong; Veerapalli, Kartik R; Wan, Jiandi

    2016-03-15

    Because the size, size distribution, and concentration of emulsions play an important role in most of the applications, controlled emulsion generation and effective concentration are of great interest in fundamental and applied studies. While microfluidics has been demonstrated to be able to produce emulsion drops with controlled size, size distribution, and hierarchical structures, progress of controlled generation of concentrated emulsions is limited. Here, we present an effective microfluidic emulsion generation system integrated with an orifice structure to separate aqueous droplets from the continuous oil phase, resulting in concentrated emulsion drops in situ. Both experimental and simulation results show that the efficiency of separation is determined by a balance between pressure drop and droplet accumulation near the orifice. By manipulating this balance via changing flow rates and microfluidic geometry, we can achieve monodisperse droplets on chip that have a concentration as high as 80,000 drops per microliter (volume fraction of 66%). The present approach thus provides insights to the design of microfluidic device that can be used to concentrate emulsions (drops and bubbles), colloidal particles (drug delivery polymer particles), and biological particles (cells and bacteria) when volume fractions as high as 66% are necessary. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Nano concentration by acoustically generated complex spiral vortex field

    NASA Astrophysics Data System (ADS)

    Tang, Qiang; Wang, Xiaofei; Hu, Junhui

    2017-03-01

    A strategy to concentrate nanoscale materials on the boundary between a nano suspension droplet and non-vibration substrate is demonstrated and analyzed. It employs the spiral vortex of acoustic streaming, generated by an ultrasonically vibrating needle parallel to and above the non-vibration substrate. The vortex drags nanoscale materials to the center of itself, forming a concentration spot. For 250 nm-diameter SiO2 nano particle suspension with an initial concentration of 0.09 mg/ml, the diameter of the concentration spot can be up to several hundred microns. The dependency of the spiral vortex field on the vibration distribution of the acoustic needle in the droplet is also clarified by experiments and computation, and the concentration conditions are obtained by analyzing the nano particle dynamics in the spiral vortex.

  4. Induced charge electro-osmotic concentration gradient generator

    PubMed Central

    Jain, Mranal; Yeung, Anthony; Nandakumar, K.

    2010-01-01

    Biomolecule gradients play an important role in the understanding of various biological processes. Typically, biological cells are exposed to linear and nonlinear concentration gradients and their response is studied for understanding cell growth, cell migration, and cell differentiation mechanisms. Recent studies have demonstrated the use of microfluidic devices for precise and stable concentration gradient generation. However, most of the reported devices are geometrically complex and lack dynamic controllability. In this work, a novel microfluidic gradient generator is presented which utilizes the induced charge electro-osmosis (ICEO) by introducing conducting obstacle in the microchannel. With the ICEO flow component, significant transverse convection can be generated within the microchannel, which can, in turn, be used to create nonlinear as well as asymmetric gradients. The characteristics of the developed concentration gradient are dependent on the interplay between fixed charge electro-osmotic and ICEO flows. It is shown that the proposed device can switch between linear and nonlinear gradients by just altering the applied electric field. Finally, the formation of user-defined concentration profiles (linear, convex, and concave) is demonstrated by varying the conducting obstacle size. PMID:20644679

  5. 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

  6. 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. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. 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.

  8. Generation of local concentration gradients by gas-liquid contacting.

    PubMed

    de Jong, Jorrit; Verheijden, Pascal W; Lammertink, Rob G H; Wessling, Matthias

    2008-05-01

    We present a generic concept to create local concentration gradients, based on the absorption of gases or vapors in a liquid. A multilayer microfluidic device with crossing gas and liquid channels is fabricated by micromilling and used to generate multiple gas-liquid contacting regions, separated by a hydrophobic membrane. Each crossing can acts as both a microdosing and microstripping region. Furthermore, the liquid and gas flow rate can be controlled independently of each other. The focus of this conceptual article is on the generation of pH gradients, by locally supplying acidic or basic gases/vapors, such as carbon dioxide, hydrochloric acid, and ammonia, visualized by pH-sensitive dyes. Stationary and moving gradients are presented in devices with 500-microm channel width, depths of 200-400 microm, and lengths of multiple centimeters. It is shown that the method allows for multiple consecutive switching gradients in a single microchannel. Absorption measurements in a microcontactor with the model system CO2/water are presented to indicate the dependence of gas absorption rate on channel depth and residence time. Achievable concentration ranges are ultimately limited by the solubility of used components. The reported devices are easy to fabricate, and their application is not limited to pH gradients. Two proof of principles are demonstrated to indicate new opportunities: (i) local crystallization of NaCl using HCl vapor and (ii) consecutive reactions of ammonia with copper(II) ions in solution.

  9. Symmetry-selective third-harmonic generation from plasmonic metacrystals.

    PubMed

    Chen, Shumei; Li, Guixin; Zeuner, Franziska; Wong, Wing Han; Pun, Edwin Yue Bun; Zentgraf, Thomas; Cheah, Kok Wai; Zhang, Shuang

    2014-07-18

    Nonlinear processes are often governed by selection rules imposed by the symmetries of the molecular configurations. The most well-known examples include the role of centrosymmetry breaking for the generation of even harmonics, and the selection rule related to the rotational symmetry in harmonic generation for fundamental beams with circular polarizations. While the role of centrosymmetry breaking in second harmonic generation has been extensively studied in plasmonic systems, the investigation of selection rules pertaining to circular polarization states of harmonic generation is limited to crystals, i.e., symmetries at the atomic level. In this Letter we demonstrate the rotational symmetry dependent third harmonic generation from nonlinear plasmonic metacrystals. We show that the selection rule can be imposed by the rotational symmetry of metacrystals embedded into an isotropic organic nonlinear thin film. The results presented here may open new avenues for designing symmetry-dependent nonlinear optical responses with tailored plasmonic nanostructures.

  10. The use of minimum selectable concentrations (MSCs) for determining the selection of antimicrobial resistant bacteria.

    PubMed

    Khan, Sadia; Beattie, Tara K; Knapp, Charles W

    2017-03-01

    The use of antimicrobial compounds is indispensable in many industries, especially drinking water production, to eradicate microorganisms. However, bacterial growth is not unusual in the presence of disinfectant concentrations that would be typically lethal, as bacterial populations can develop resistance. The common metric of population resistance has been based on the Minimum Inhibitory Concentration (MIC), which is based on bacteria lethality. However, sub-lethal concentrations may also select for resistant bacteria due to the differences in bacterial growth rates. This study determined the Minimal Selective Concentrations (MSCs) of bacterial populations exposed to free chlorine and monochloramine, representing a metric that possibly better reflects the selective pressures occurring at lower disinfectant levels than MIC. Pairs of phylogenetically similar bacteria were challenged to a range of concentrations of disinfectants. The MSCs of free chlorine and monochloramine were found to range between 0.021 and 0.39 mg L(-1), which were concentrations 1/250 to 1/5 than the MICs of susceptible bacteria (MIC susc ). This study indicates that sub-lethal concentrations of disinfectants could result in the selection of resistant bacterial populations, and MSCs would be a more sensitive indicator of selective pressure, especially in environmental systems.

  11. Influence of target concentration and background binding on in vitro selection of affinity reagents.

    PubMed

    Wang, Jinpeng; Rudzinski, Joseph F; Gong, Qiang; Soh, H Tom; Atzberger, Paul J

    2012-01-01

    Nucleic acid-based aptamers possess many useful features that make them a promising alternative to antibodies and other affinity reagents, including well-established chemical synthesis, reversible folding, thermal stability and low cost. However, the selection process typically used to generate aptamers (SELEX) often requires significant resources and can fail to yield aptamers with sufficient affinity and specificity. A number of seminal theoretical models and numerical simulations have been reported in the literature offering insights into experimental factors that govern the effectiveness of the selection process. Though useful, these previous models have not considered the full spectrum of experimental factors or the potential impact of tuning these parameters at each round over the course of a multi-round selection process. We have developed an improved mathematical model to address this important question, and report that both target concentration and the degree of non-specific background binding are critical determinants of SELEX efficiency. Although smaller target concentrations should theoretically offer superior selection outcome, we show that the level of background binding dramatically affect the target concentration that will yield maximum enrichment at each round of selection. Thus, our model enables experimentalists to determine appropriate target concentrations as a means for protocol optimization. Finally, we perform a comparative analysis of two different selection methods over multiple rounds of selection, and show that methods with inherently lower background binding offer dramatic advantages in selection efficiency.

  12. Influence of Target Concentration and Background Binding on In Vitro Selection of Affinity Reagents

    PubMed Central

    Wang, Jinpeng; Rudzinski, Joseph F.; Gong, Qiang; Soh, H. Tom; Atzberger, Paul J.

    2012-01-01

    Nucleic acid-based aptamers possess many useful features that make them a promising alternative to antibodies and other affinity reagents, including well-established chemical synthesis, reversible folding, thermal stability and low cost. However, the selection process typically used to generate aptamers (SELEX) often requires significant resources and can fail to yield aptamers with sufficient affinity and specificity. A number of seminal theoretical models and numerical simulations have been reported in the literature offering insights into experimental factors that govern the effectiveness of the selection process. Though useful, these previous models have not considered the full spectrum of experimental factors or the potential impact of tuning these parameters at each round over the course of a multi-round selection process. We have developed an improved mathematical model to address this important question, and report that both target concentration and the degree of non-specific background binding are critical determinants of SELEX efficiency. Although smaller target concentrations should theoretically offer superior selection outcome, we show that the level of background binding dramatically affect the target concentration that will yield maximum enrichment at each round of selection. Thus, our model enables experimentalists to determine appropriate target concentrations as a means for protocol optimization. Finally, we perform a comparative analysis of two different selection methods over multiple rounds of selection, and show that methods with inherently lower background binding offer dramatic advantages in selection efficiency. PMID:22952815

  13. Concentration of selected metals in muscle of various fish species.

    PubMed

    Andreji, Jaroslav; Stránai, Ivan; Massányi, Peter; Valent, Miroslav

    2005-01-01

    The purpose of this study was to assess concentration of selected metals (Fe, Mn, Zn, Cu, Ni, Co, Cr, Pb, Cd, and Hg) in the muscle of four common Slovak fish species (chub--Leuciscus cephalus, barbel--Barbus barbus, roach--Rutilus rutilus, and perch--Perca fluviatilis). Furthermore, correlations among the selected metals and order of metal accumulation in the fish muscle were determined. An electrofishing technique was used for collecting the fish from the Nitra River (Slovakia) in September 2003. Concentrations of selected metals were measured using an atomic absorption spectrophotometer Pye Unicam SP9. The concentrations of metals (mg/kg wet weight basis) ranged as follows: Fe 3.41-15.14; Mn 0.20-0.81; Zn 3.51-15.64; Cu 0.25-0.78; Ni 0.07-0.25; Co 0.05-0.19; Cr 0.11-0.42; Pb 0.20-5.81; Cd 0.06-0.56, and Hg 1.35-6.52. Significant correlations (P < 0.05) between Fe-Cu, Fe-Ni, Fe-Cr, Mn-Ni, Mn-Cr, Mn-Cr, Cu-Ni, and Ni-Cr were observed. The level of lead exceeded the maximum allowable concentration in Slovakia by Codex Alimentarius for safe human consumption (0.2 mg/kg) in the majority of samples (97.2%). Content of Cd (0.23 +/- 0.13 mg/kg wet weight) and Hg (2.85 +/- 1.22 mg/kg wet weight) in the fish muscle exceeded maximum allowed levels in all samples. On average, the order of metal concentrations in the fish muscle was: Fe > Zn > Hg > Pb > Cu > Mn > Cd > Cr > Ni > Co.

  14. Photovoltaic systems based on spectrally selective holographic concentrators

    NASA Astrophysics Data System (ADS)

    Ludman, Jacques E.; Sampson, John L.; Bradbury, Rudolph A.; Martin, Jose G.; Riccobono, Juanita R.; Sliker, Guy; Rallis, Evangelos

    1992-05-01

    A holographic device has been developed that greatly improves the efficiency of solar energy conversion. The single-element hologram focuses light to the side and also spectrally splits it. The output appears as a thin concentrated line, focused perpendicular to the hologram and displaced to the side. Different wavelengths are diffracted, concentrated, and dispersed to different locations on the line which resembles an elegant rainbow in the visible. The hologram lets each of two or more different solar cells absorb only those wavelengths which can efficiently convert to electric power. The device also prevents overheating by diffracting unwanted infrared radiation away from the cells. The side focus eliminates shadow effects, and cooling is easy, since the cells are not cascaded and the heat load is minimal. This novel system is ideal for concentrated, split-spectrum, high efficiency solar power generation.

  15. 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.

  16. (68)Ga generator integrated system: elution-purification-concentration integration.

    PubMed

    Le, Van So

    2013-01-01

    A (68)Ge/(68)Ga generator combined with an automated (68)Ga eluate purification-concentration unit [radioisotope generator integrated system (RADIGIS)], specially designed for (68)Ga processing (RADIGIS-(68)Ga), was developed. The high-stability sorbents of a nanocrystalline structure Zr-Ti ceramic matrix were used for immobilizing the (68)Ge, and the (68)Ga was eluted from the sorbent column with 3.5 mL 0.05-0.1 M HCl solution following an optimized (68)Ga-elution schedule. The (68)Ge breakthrough <10(-3)% and no (68)Ge zone spreading/drift found in PET imaging of the (68)Ga generator column prove the excellent performance of the sorbents. (68)Ga eluate was purified on a small column of salt-form ion exchange resin using an aqueous alcohol solution mixture of hydrochloric and ascorbic acids, and halide salts. An alkali solution was used for stripping (68)Ga from the ion exchange resin column to obtain a purified (68)Ga solution, which is conditioned with acidic solution to obtain a final (68)Ga product in either 0.75 mL 0.5 M NaCl solution of pH 3-4 or 0.5 M sodium acetate or citrate solution of pH 5. The (68)Ge content in purified (68)Ga solution was <10(-6)%. An insignificant metallic contamination including (68)Zn found in the (68)Ga solution and its alkalinity-acidity were evaluated with respect to (68)Ga radiolabeling efficacy for DOTATATE and DOTATOC ligands. Quality control protocols were also developed to evaluate the quality of (68)Ga solution.

  17. 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.

  18. 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.

  19. Selective dynamic concentration of peptides at poles of cation-selective nanoporous granules

    PubMed Central

    Chen, Hsiao-Ping; Tsai, Chia-Chun; Lee, Hung-Meng; Wang, Shau-Chun; Chang, Hsueh-Chia

    2013-01-01

    The authors exposed a non-equilibrium dynamic counterion and coion analyte concentration to an AC electric field to selectively concentrate peptides at the poles of a cation-selective granule. The counterion polarization results from the focusing of the electric field show a discontinuous drop in the intra-granule counterion electromigration flux at the pole. The coion concentration polarization is due to the combined external convective and electromigration fluxes toward the pole that neutralize the accumulating counterions. Because the electromigration mobility of the peptide anion analyte depends on the pH, the authors determined a 20 000-fold high concentration factor for a near-neutral pH of 6.0 to 7.7. Because the peptide is protonated at the acidic pole and its absolute charge ranges from −0.3 to −1.9, the concentration factor scales exponentially with the absolute charge, thus allowing extremely selective concentrations of various peptides, which is demonstrated by fluorescein isothiocyanate tagged angiotensin I (pI ∼ 5.8) and Texas red tagged avidin (pI ∼ 10.5). This dynamic concentration effect can substantially enhance the sensitivity of bio-assays. PMID:24404043

  20. The generation of concentration gradients using electroosmotic flow in micro reactors allowing stereoselective chemical synthesis.

    PubMed

    Skelton, V; Greenway, G M; Haswell, S J; Styring, P; Morgan, D O; Warrington, B H; Wong, S Y

    2001-01-01

    The stereoselective control of chemical reactions has been achieved by applying electrical fields in a micro reactor generating controlled concentration gradients of the reagent streams. The chemistry based upon well-established Wittig synthesis was carried out in a micro reactor device fabricated in borosilicate glass using photolithographic and wet etching techniques. The selectivity of the cis (Z) to trans (E) isomeric ratio in the product synthesised was controlled by varying the applied voltages to the reagent reservoirs within the micro reactor. This subsequently altered the relative reagent concentrations within the device resulting in Z/E ratios in the range 0.57-5.21. By comparison, a traditional batch method based on the same reaction length, concentration, solvent and stoichiometry (i.e., 1.0:1.5:1.0 reagent ratios) gave a Z/E in the range 2.8-3.0. However, when the stoichiometric ratios were varied up to ten times as much, the Z/E ratios varied in accordance to the micro reactor i.e., when the aldehyde is in excess, the Z isomer predominates whereas when the aldehyde is in low concentrations, the E isomer is the more favourable form. Thus indicating that localised concentration gradients generated by careful flow control due to the diffusion limited non-turbulent mixing regime within a micro reactor, leads to the observed stereo selectivity for the cis and trans isomers.

  1. 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.

  2. Measurement of Radon Concentration in Selected Houses in Ibadan, Nigeria

    NASA Astrophysics Data System (ADS)

    Usikalu, M. R.; Olatinwo, V.; Akpochafor, M.; Aweda, M. A.; Giannini, G.; Massimo, V.

    2017-05-01

    Radon is a natural radioactive gas without colour or odour and tasteless. The World Health Organization (WHO) grouped radon as a human lung carcinogen. For this reason, there has been a lot of interest on the effects of radon exposure to people all over the world and Nigeria is no exception. The aim of this study is to investigate the radon concentration in selected houses in three local government areas of Ibadan. The indoor radon was measured in both mud and brick houses. Fifty houses were considered from the three Local government areas. A calibrated portable continuous radon monitor type (RAD7) manufactured by Durridge company was used for the measurement. A distance of 100 to 200 m was maintained between houses in all the locations. The living room was kept closed during the measurements. The mean radon concentration measured in Egbeda is 10.54 ±1.30 Bqm -3; Lagelu is 16.90 ± 6.31 Bqm -3 and Ona-Ara is 17.95 ± 1.72 Bqm -3. The mean value of the annual absorbed dose and annual effective dose for the locations in the three local government areas was 0.19 mSvy-1 and 0.48 mSvy-1 respectively. The radon concentration for location 10 in Ono-Ara local government exceeded the recommended limit. However, the overall average indoor radon concentration of the three local governments was found to be lower than the world average value of 40 Bqm -3. Hence, there is need for proper awareness about the danger of radon accumulation in dwelling places.

  3. Generation, use, and validation of receptor-selective antibodies.

    PubMed

    Mackrill, John J

    2004-01-01

    Antibodies have proved invaluable in the study of G-protein-coupled receptors (GPCRs). The utility of these immunoglobulin probes for investigation of protein structures and functions arises from their selectivity as well as their versatility. Antibodies can be used to analyze GPCR size, abundance, distribution, turnover, modification, interaction with other proteins, and functional properties. In this chapter, techniques for the generation and characterization of receptor-selective antibodies are described. Two protocols are given for the generation of antibodies: (1) development of polyclonal antibodies (PAbs) against synthetic peptides corresponding to a specific site within a GPCR and (2) selection of synthetic single-chain fragment variable (scFv) monoclonal antibodies (MAbs) from libraries expressed on the surface of bacteriophage. Immunoblot and enzyme-linked immunosorbent assays for characterization of the selectivity and affinity of such antibodies are described. Finally, methods are given for improvement of the titer and specificity of PAbs.

  4. 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.

  5. Rock Concentration and Thermal Inertia of Selected Lunar Study Regions.

    NASA Astrophysics Data System (ADS)

    Bauch, K. E.; Hiesinger, H.

    2012-04-01

    Temperature variations of lunar and planetary surfaces are directly influenced by their surface and subsurface thermophysical properties [1, 2]. These properties, namely bulk density, heat capacity, and thermal conductivity, are represented by thermal inertia, which is the ability of a surface and subsurface to conduct and store heat [2]. Materials with a low thermal inertia, such as dust and other fine-grained material, quickly respond to temperature changes, which results in a large temperature amplitude during the lunar cycle. Surfaces with high thermal inertia material, e.g. rocks or bedrock, take more time to heat up during the lunar day and reradiate the heat over extended periods. We derived maps of thermal inertia from LRO-Diviner nighttime temperature data [3]. The data was binned in one hour intervals with a minimum spatial resolution of 32 pixels/degree. For each surface facet we generated temperature-to-inertia look-up tables using a thermal model that solves the 1-D heat conduction equation. Model temperatures were then compared to measured data to find the best-fitting thermal inertia value. This approach is similar to martian thermal inertia derivations, as described by Mellon et al. (2000) and Putzig et al. (2005) [2, 4]. Due to the relatively large footprints of the used remote sensing data, anisothermal surfaces are observed within the field of view. Consequently, multiple thermal inertia units having variable temperatures are merged to a single observed temperature. However, the brightness temperature is a function of wavelength - it increases with decreasing wavelength. This nonlinearity of the Planck radiance can be used to determine rock concentrations [e.g., 5-7]. Therefore we used our model surface temperatures calculated with different thermal inertia and rock concentrations and compared these results to the LRO-Diviner temperature data at several wavelengths. The results were also compared to high-resolution Apollo and Lunar Reconnaissance

  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. 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.

  8. Pyridine-antipyrine appended indole derivative for selective recognition of Fe3 +: Concentration dependent coloration

    NASA Astrophysics Data System (ADS)

    Ta, Sabyasachi; Nandi, Sandip; Ghosh, Milan; Banerjee, Somenath; Das, Debasis

    2017-02-01

    Combination of pyridine, antipyrine and indole in a single molecule (L2) allows selective recognition of Fe3 + colorimetrically in CH3CN. The structure of L2 is confirmed from single crystal X-ray diffraction analysis. The probe displays two different visible bands at 541 nm and 715 nm in the presence of Fe3 +, associated with two different colors, viz. green and pink-violet allowing determination of unknown Fe3 + concentration. Interestingly, removal of 2-picolyl group from indole N-center of L2 generates L3 that behaves similarly at low Fe3 + concentration (> 0 to 1.1 mM) but differently at higher Fe3 + concentration (> 1.1 mM), indicating involvement of pyridyl-N donor towards Fe3 +, and hence different coordination environment around Fe3 + at higher concentration.

  9. 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…

  10. Genetic Variation and the Effectiveness of Early Generation Selection

    USDA-ARS?s Scientific Manuscript database

    Selection of wheat (Triticum aestivum L.) milling and baking quality in single-environment, non-replicated early-generation head-rows would increase the efficiency of most soft winter wheat (SWW) breeding programs. This study (i) estimated the heritability of SWW quality and gluten strength in a cr...

  11. 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…

  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. Thermophotovoltaic generation with selective radiators based on tungsten surface gratings

    NASA Astrophysics Data System (ADS)

    Sai, Hitoshi; Yugami, Hiroo

    2004-10-01

    Two-dimensional surface-relief gratings with a period of 1.0-0.2μm composed of rectangular microcavities were fabricated on single crystalline W substrates to develop spectrally selective radiators for thermophotovoltaic generation. The radiators displayed strong emission in the near-infrared region where narrow-band-gap photovoltaic cells could convert photons into electricity. The enhancement of thermal emission was attributed to the microcavity effect. Power generation tests were carried out and the W gratings showed more than two times higher generation efficiency, compared to a SiC radiator. The results showed that the microstructured W radiators behave as good selective radiator, with both high efficiency and high power density.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. 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. © 2011 Macmillan Publishers Limited. All rights reserved

  16. Concentrating solar thermoelectric generators with a peak efficiency of 7.4%

    NASA Astrophysics Data System (ADS)

    Kraemer, Daniel; Jie, Qing; McEnaney, Kenneth; Cao, Feng; Liu, Weishu; Weinstein, Lee A.; Loomis, James; Ren, Zhifeng; Chen, Gang

    2016-11-01

    Concentrating solar power normally employs mechanical heat engines and is thus only used in large-scale power plants; however, it is compatible with inexpensive thermal storage, enabling electricity dispatchability. Concentrating solar thermoelectric generators (STEGs) have the advantage of replacing the mechanical power block with a solid-state heat engine based on the Seebeck effect, simplifying the system. The highest reported efficiency of STEGs so far is 5.2%. Here, we report experimental measurements of STEGs with a peak efficiency of 9.6% at an optically concentrated normal solar irradiance of 211 kW m-2, and a system efficiency of 7.4% after considering optical concentration losses. The performance improvement is achieved by the use of segmented thermoelectric legs, a high-temperature spectrally selective solar absorber enabling stable vacuum operation with absorber temperatures up to 600 ∘C, and combining optical and thermal concentration. Our work suggests that concentrating STEGs have the potential to become a promising alternative solar energy technology.

  17. Dispersion engineering and frequency comb generation in thin silicon nitride concentric microresonators.

    PubMed

    Kim, Sangsik; Han, Kyunghun; Wang, Cong; Jaramillo-Villegas, Jose A; Xue, Xiaoxiao; Bao, Chengying; Xuan, Yi; Leaird, Daniel E; Weiner, Andrew M; Qi, Minghao

    2017-08-29

    Kerr nonlinearity-based frequency combs and solitons have been generated from on-chip microresonators. The initiation of the combs requires global or local anomalous dispersion which leads to many limitations, such as material choice, film thickness, and spectral ranges where combs can be generated, as well as fabrication challenges. Using a concentric racetrack-shaped resonator, we show that such constraints can be lifted and resonator dispersion can be engineered to be anomalous over moderately broad bandwidth. We demonstrate anomalous dispersion in a 300 nm thick silicon nitride film, suitable for semiconductor manufacturing but previously thought to result in waveguides with high normal dispersion. Together with a mode-selective, tapered coupling scheme, we generate coherent mode-locked frequency combs. Our method can realize anomalous dispersion for resonators at almost any wavelength and simultaneously achieve material and process compatibility with semiconductor manufacturing.Kerr frequency comb generation from microresonators requires anomalous dispersion, imposing restrictions on materials and resonator design. Here, Kim et al. propose a concentric racetrack-resonator design where the dispersion can be engineered to be anomalous via resonant mode coupling.

  18. Discussion on the solar concentrating thermoelectric generation using micro-channel heat pipe array

    NASA Astrophysics Data System (ADS)

    Li, Guiqiang; Feng, Wei; Jin, Yi; Chen, Xiao; Ji, Jie

    2017-03-01

    Heat pipe is a high efficient tool in solar energy applications. In this paper, a novel solar concentrating thermoelectric generation using micro-channel heat pipe array (STEG-MCHP) was presented. The flat-plate micro-channel heat pipe array not only has a higher heat transfer performance than the common heat pipe, but also can be placed on the surface of TEG closely, which can further reduce the thermal resistance between the heat pipe and the TEG. A preliminary comparison experiment was also conducted to indicate the advantages of the STEG-MCHP. The optimization based on the model verified by the experiment was demonstrated, and the concentration ratio and selective absorbing coating area were also discussed. In addition, the cost analysis was also performed to compare between the STEG-MCHP and the common solar concentrating TEGs in series. The outcome showed that the solar concentrating thermoelectric generation using micro-channel heat pipe array has the higher electrical efficiency and lower cost, which may provide a suitable way for solar TEG applications.

  19. Rapid Generation of Highly Specific Aptamers via Micromagnetic Selection

    PubMed Central

    Qian, Jiangrong; Lou, Xinhui; Zhang, Yanting; Xiao, Yi; Soh, H. Tom

    2009-01-01

    Aptamers are nucleic acid-based reagents that bind to target molecules with high affinity and specificity. However, methods for generating aptamers from random combinatorial libraries (e.g., SELEX) are often labor-intensive and time-consuming. Recent studies suggest that microfluidic SELEX (M-SELEX) technology can accelerate aptamer isolation by enabling highly stringent selection conditions through the use of very small amounts of target molecules. We present here an alternative M-SELEX method, which employs a disposable microfluidic chip to rapidly generate aptamers with high affinity and specificity. The Micro-Magnetic Separation (MMS) chip integrates microfabricated ferromagnetic structures to reproducibly generate large magnetic field gradients within its microchannel that efficiently trap magnetic bead-bound aptamers. Operation of the MMS device is facile, robust and demonstrates high recovery of the beads (99.5%), such that picomolar amounts of target molecule can be used. Importantly, the device demonstrates exceptional separation efficiency in removing weakly-bound and unbound ssDNA to rapidly enrich target-specific aptamers. As a model, we demonstrate here the generation of DNA aptamers against streptavidin in three rounds of positive selection. We further enhanced the specificity of the selected aptamers via a round of negative selection in the same device against bovine serum albumin (BSA). The resulting aptamers displayed dissociation constants ranging from 25 to 65 nM for streptavidin but negligible affinity for BSA. Since a wide spectrum of molecular targets can be readily conjugated on magnetic beads, MMS-based SELEX should provide a general platform for rapid generation of specific aptamers. PMID:19480397

  20. Acalabrutinib (ACP-196): a selective second-generation BTK inhibitor.

    PubMed

    Wu, Jingjing; Zhang, Mingzhi; Liu, Delong

    2016-03-09

    More and more targeted agents become available for B cell malignancies with increasing precision and potency. The first-in-class Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, has been in clinical use for the treatment of chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom's macroglobulinemia. More selective BTK inhibitors (ACP-196, ONO/GS-4059, BGB-3111, CC-292) are being explored. Acalabrutinib (ACP-196) is a novel irreversible second-generation BTK inhibitor that was shown to be more potent and selective than ibrutinib. This review summarized the preclinical research and clinical data of acalabrutinib.

  1. 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

  2. Linear conversion of pressure into concentration, rapid switching of concentration, and generation of linear ramps of concentration in a microfluidic device.

    PubMed

    Adler, Micha; Groisman, Alex

    2012-06-01

    Mixing of liquids to produce solutions with different concentrations is one of the basic functionalities of microfluidic devices. Generation of specific temporal patterns of concentration in microfluidic devices is an important technique to study responses of cells and model organisms to variations in the chemical composition of their environment. Here, we present a simple microfluidic network that linearly converts pressure at an inlet into concentration of a soluble reagent in an observation region and also enables independent concurrent linear control of concentrations of two reagents. The microfluidic device has an integrated mixer channel with chaotic three-dimensional flow that facilitates rapid switching of concentrations in a continuous range. A simple pneumatic setup generating linear ramps of pressure is used to produce smooth linear ramps and triangular waves of concentration with different slopes. The use of chaotic vs. laminar mixers is discussed in the context of microfluidic devices providing rapid switching and generating temporal waves of concentration.

  3. Concept selection and analysis of large wind generator systems

    NASA Technical Reports Server (NTRS)

    Meier, R. C.

    1975-01-01

    The increasing need to develop alternative energy sources has renewed interest in the use of wind energy for the generation of utility quality electricity. This paper discusses a program to evolve a preliminary design of a cost competitive large wind generator system. An examination of a number of technically feasible alternative wind energy configurations is reported, and the rationale used in selecting the preferred system concept is presented. In addition, preliminary results of an optimization study conducted on the preferred concept are summarized. These show that considerable latitude in the selection of the system design parameters is possible. This permits design decisions to be based on other important factors such as development risk and the suitability of common component designs for systems with different power ratings.

  4. 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.

  5. Selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers

    NASA Astrophysics Data System (ADS)

    Li, Ming-Liang; Deng, Ming-Xi; Gao, Guang-Jian

    2016-12-01

    In this paper, we describe a modal expansion approach for the analysis of the selective generation of ultrasonic Lamb waves by electromagnetic acoustic transducers (EMATs). With the modal expansion approach for waveguide excitation, an analytical expression of the Lamb wave’s mode expansion coefficient is deduced, which is related to the driving frequency and the geometrical parameters of the EMAT’s meander coil, and lays a theoretical foundation for exactly analyzing the selective generation of Lamb waves with EMATs. The influences of the driving frequency on the mode expansion coefficient of ultrasonic Lamb waves are analyzed when the EMAT’s geometrical parameters are given. The numerical simulations and experimental examinations show that the ultrasonic Lamb wave modes can be effectively regulated (strengthened or restrained) by choosing an appropriate driving frequency of EMAT, with the geometrical parameters given. This result provides a theoretical and experimental basis for selectively generating a single and pure Lamb wave mode with EMATs. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474361 and 11274388).

  6. Environmental heterogeneity generates fluctuating selection on a secondary sexual trait.

    PubMed

    Robinson, Matthew R; Pilkington, Jill G; Clutton-Brock, Tim H; Pemberton, Josephine M; Kruuk, Loeske E B

    2008-05-20

    In any population in which resources are limiting, the allocation of resources toward increased reproductive success may generate costs to survival [1-8]. The relationship between a sexually selected trait and fitness will therefore represent a balance between its relative associations with fecundity versus viability [3, 6, 7]. Because the risk of mortality in a population is likely to be heavily determined by ecological conditions, survival costs may vary as a function of the prevailing environment [7]. As a result, for populations experiencing heterogeneous ecological conditions, there may not be a single optimal level of allocation toward reproduction versus survival [9]. Here, we show that early viability and fecundity selection act in opposing directions on a secondary sexual trait and that their relative magnitude depends upon ecological conditions, generating fluctuating selection. In a wild population of Soay sheep (Ovis aries), phenotypic and genetic associations between male horn growth and lifetime reproductive success were positive under good environmental conditions (because of increased breeding success) and negative under poor environmental conditions (because of reduced survival). In an unpredictable environment, high allocation to early horn growth is a gamble that will only pay off if ensuing conditions are favorable. Such fluctuating selection may play an important role in preventing the erosion of genetic variance in secondary sexual traits.

  7. Solar-hydrogen generation and solar concentration (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Chinello, Enrico; Modestino, Miguel A.; Schüttauf, Jan-Willem; Lambelet, David; Delfino, Antonio; Dominé, Didier; Faes, Antonin; Despeisse, Matthieu; Bailat, Julien; Psaltis, Demetri; Fernandez Rivas, David; Ballif, Christophe; Moser, Christophe

    2016-09-01

    We successfully demonstrated and reported the highest solar-to-hydrogen efficiency with crystalline silicon cells and Earth-abundant electrocatalysts under unconcentrated solar radiation. The combination of hetero-junction silicon cells and a 3D printed Platinum/Iridium-Oxide electrolyzer has been proven to work continuously for more than 24 hours in neutral environment, with a stable 13.5% solar-to-fuel efficiency. Since the hydrogen economy is expected to expand to a global scale, we demonstrated the same efficiency with an Earth-abundant electrolyzer based on Nickel in a basic medium. In both cases, electrolyzer and photovoltaic cells have been specifically sized for their characteristic curves to intersect at a stable operating point. This is foreseen to guarantee constant operation over the device lifetime without performance degradation. The next step is to lower the production cost of hydrogen by making use of medium range solar concentration. It permits to limit the photoabsorbing area, shown to be the cost-driver component. We have recently modeled a self-tracking solar concentrator, able to capture sunlight within the acceptance angle range +/-45°, implementing 3 custom lenses. The design allows a fully static device, avoiding the external tracker that was necessary in a previously demonstrated +/-16° angular range concentrator. We will show two self-tracking methods. The first one relies on thermal expansion whereas the second method relies on microfluidics.

  8. 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.

  9. Third generation antipsychotic drugs: partial agonism or receptor functional selectivity?

    PubMed Central

    Mailman, Richard B.; Murthy, Vishakantha

    2010-01-01

    Functional selectivity is the term that describes drugs that cause markedly different signaling through a single receptor (e.g., full agonist at one pathway and antagonist at a second). It has been widely recognized recently that this phenomenon impacts the understanding of mechanism of action of some drugs, and has relevance to drug discovery. One of the clinical areas where this mechanism has particular importance is in the treatment of schizophrenia. Antipsychotic drugs have been grouped according to both pattern of clinical action and mechanism of action. The original antipsychotic drugs such as chlorpromazine and haloperidol have been called typical or first generation. They cause both antipsychotic actions and many side effects (extrapyramidal and endocrine) that are ascribed to their high affinity dopamine D2 receptor antagonism. Drugs such as clozapine, olanzapine, risperidone and others were then developed that avoided the neurological side effects (atypical or second generation antipsychotics). These compounds are divided mechanistically into those that are high affinity D2 and 5-HT2A antagonists, and those that also bind with modest affinity to D2, 5-HT2A, and many other neuroreceptors. There is one approved third generation drug, aripiprazole, whose actions have been ascribed alternately to either D2 partial agonism or D2 functional selectivity. Although partial agonism has been the more widely accepted mechanism, the available data are inconsistent with this mechanism. Conversely, the D2 functional selectivity hypothesis can accommodate all current data for aripiprazole, and also impacts on discovery compounds that are not pure D2 antagonists. PMID:19909227

  10. Evidence generation for wound care dressing selection: reviewing the issues.

    PubMed

    Pagnamenta, F

    2017-09-02

    In the UK, dressings are categorised as medical devices and manufacturers only have to provide limited evidence of effectiveness before dressings are used in clinical practice. Therefore, evidence based on clinical trial methods is scant. As a direct result, governing bodies in the UK are now recommending that decisions to select one dressing over another could mainly be made on price. Placed within the movement critiquing evidence-based practice (EBP), this paper summarises the main issues surrounding the generation of evidence in selecting dressings for wound care, which is immersed in a context that lacks resources, legislative clarity and freedom to choose methodological alternatives. Dressings are therapeutic medical devices rather than consumables and any rationalisation based on costs may have far-reaching implications for wound care clinicians through purchasing decisions and thus may limit their ability to manage wounds effectively.

  11. 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.

  12. Materials for next-generation molecularly selective synthetic membranes

    NASA Astrophysics Data System (ADS)

    Koros, William J.; Zhang, Chen

    2017-03-01

    Materials research is key to enable synthetic membranes for large-scale, energy-efficient molecular separations. Materials with rigid, engineered pore structures add an additional degree of freedom to create advanced membranes by providing entropically moderated selectivities. Scalability -- the capability to efficiently and economically pack membranes into practical modules -- is a critical yet often neglected factor to take into account for membrane materials screening. In this Progress Article, we highlight continuing developments and identify future opportunities in scalable membrane materials based on these rigid features, for both gas and liquid phase applications. These advanced materials open the door to a new generation of membrane processes beyond existing materials and approaches.

  13. Materials for next-generation molecularly selective synthetic membranes.

    PubMed

    Koros, William J; Zhang, Chen

    2017-03-01

    Materials research is key to enable synthetic membranes for large-scale, energy-efficient molecular separations. Materials with rigid, engineered pore structures add an additional degree of freedom to create advanced membranes by providing entropically moderated selectivities. Scalability - the capability to efficiently and economically pack membranes into practical modules - is a critical yet often neglected factor to take into account for membrane materials screening. In this Progress Article, we highlight continuing developments and identify future opportunities in scalable membrane materials based on these rigid features, for both gas and liquid phase applications. These advanced materials open the door to a new generation of membrane processes beyond existing materials and approaches.

  14. 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.

  15. Application of tripolar concentric electrodes and prefeature selection algorithm for brain-computer interface.

    PubMed

    Besio, Walter G; Cao, Hongbao; Zhou, Peng

    2008-04-01

    For persons with severe disabilities, a brain-computer interface (BCI) may be a viable means of communication. Lapalacian electroencephalogram (EEG) has been shown to improve classification in EEG recognition. In this work, the effectiveness of signals from tripolar concentric electrodes and disc electrodes were compared for use as a BCI. Two sets of left/right hand motor imagery EEG signals were acquired. An autoregressive (AR) model was developed for feature extraction with a Mahalanobis distance based linear classifier for classification. An exhaust selection algorithm was employed to analyze three factors before feature extraction. The factors analyzed were 1) length of data in each trial to be used, 2) start position of data, and 3) the order of the AR model. The results showed that tripolar concentric electrodes generated significantly higher classification accuracy than disc electrodes.

  16. 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.

  17. 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.

  18. 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)

  19. Enhanced Diffusion Weighting Generated by Selective Adiabatic Pulse Trains

    PubMed Central

    Sun, Ziqi; Bartha, Robert

    2007-01-01

    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 to Ph-6) were studied on a 4T 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 mM – 0.8 mM) water solutions (Ph-2 to 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 1H2O 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. PMID:17600741

  20. 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

  1. 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.

  2. 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.

  3. Microbiome Selection Could Spur Next-Generation Plant Breeding Strategies

    PubMed Central

    Gopal, Murali; Gupta, Alka

    2016-01-01

    “No plant is an island too…” Plants, though sessile, have developed a unique strategy to counter biotic and abiotic stresses by symbiotically co-evolving with microorganisms and tapping into their genome for this purpose. Soil is the bank of microbial diversity from which a plant selectively sources its microbiome to suit its needs. Besides soil, seeds, which carry the genetic blueprint of plants during trans-generational propagation, are home to diverse microbiota that acts as the principal source of microbial inoculum in crop cultivation. Overall, a plant is ensconced both on the outside and inside with a diverse assemblage of microbiota. Together, the plant genome and the genes of the microbiota that the plant harbors in different plant tissues, i.e., the ‘plant microbiome,’ form the holobiome which is now considered as unit of selection: ‘the holobiont.’ The ‘plant microbiome’ not only helps plants to remain fit but also offers critical genetic variability, hitherto, not employed in the breeding strategy by plant breeders, who traditionally have exploited the genetic variability of the host for developing high yielding or disease tolerant or drought resistant varieties. This fresh knowledge of the microbiome, particularly of the rhizosphere, offering genetic variability to plants, opens up new horizons for breeding that could usher in cultivation of next-generation crops depending less on inorganic inputs, resistant to insect pest and diseases and resilient to climatic perturbations. We surmise, from ever increasing evidences, that plants and their microbial symbionts need to be co-propagated as life-long partners in future strategies for plant breeding. In this perspective, we propose bottom–up approach to co-propagate the co-evolved, the plant along with the target microbiome, through – (i) reciprocal soil transplantation method, or (ii) artificial ecosystem selection method of synthetic microbiome inocula, or (iii) by exploration of

  4. Microbiome Selection Could Spur Next-Generation Plant Breeding Strategies.

    PubMed

    Gopal, Murali; Gupta, Alka

    2016-01-01

    "No plant is an island too…" Plants, though sessile, have developed a unique strategy to counter biotic and abiotic stresses by symbiotically co-evolving with microorganisms and tapping into their genome for this purpose. Soil is the bank of microbial diversity from which a plant selectively sources its microbiome to suit its needs. Besides soil, seeds, which carry the genetic blueprint of plants during trans-generational propagation, are home to diverse microbiota that acts as the principal source of microbial inoculum in crop cultivation. Overall, a plant is ensconced both on the outside and inside with a diverse assemblage of microbiota. Together, the plant genome and the genes of the microbiota that the plant harbors in different plant tissues, i.e., the 'plant microbiome,' form the holobiome which is now considered as unit of selection: 'the holobiont.' The 'plant microbiome' not only helps plants to remain fit but also offers critical genetic variability, hitherto, not employed in the breeding strategy by plant breeders, who traditionally have exploited the genetic variability of the host for developing high yielding or disease tolerant or drought resistant varieties. This fresh knowledge of the microbiome, particularly of the rhizosphere, offering genetic variability to plants, opens up new horizons for breeding that could usher in cultivation of next-generation crops depending less on inorganic inputs, resistant to insect pest and diseases and resilient to climatic perturbations. We surmise, from ever increasing evidences, that plants and their microbial symbionts need to be co-propagated as life-long partners in future strategies for plant breeding. In this perspective, we propose bottom-up approach to co-propagate the co-evolved, the plant along with the target microbiome, through - (i) reciprocal soil transplantation method, or (ii) artificial ecosystem selection method of synthetic microbiome inocula, or (iii) by exploration of microRNA transfer

  5. Global concentrations of selected halocarbons, 1988-1992

    SciTech Connect

    Wang, J.L.C.

    1993-12-31

    During a period of 5 years, 1988 to 1992, 15 field sampling trips have been completed in an effort to continue monitoring background atmospheric concentration of 6 man-made halocarbons, i.e., CCl{sub 2}F{sub 2} (CFC-12), CCl{sub 3}F (CFC-11), CCl{sub 2}FCClF{sub 2} (CFC-113), CH{sub 3}CCl{sub 3}, CCl{sub 4}, and C{sub 2}Cl{sub 4}. Approximately 70 to 90 flask air samples were collected 3 to 4 times a year from remote surface locations in the Pacific, ranging between latitudes 72{degrees}N and 47{degrees}S. The samples were analyzed in the laboratory at University of California, Irvine employing cryogenic sample preconcentration, gas chromatographic separation and electron capture detection. Diluted air mixtures made from pure halocarbons were rigorously formulated to the part per trillion by volume levels (x10{sup {minus}12}) and were employed to calibrate the absolute halocarbon concentrations of a whole air sample used as a working standard in the sample analysis. The absolute calibrations performed on three chlorofluorocarbons (CFCs) yielded winter-1992 averaged global concentrations of 80, 498, and 266 pptv for CFC-11, CFC-12, and CFC-113, respectively. Among the halocarbons measured CFC-11, CFC-12, and CFC-113 have been studied in detail including the changes in their temporal trends, north-to-south gradients, rates of increase, etc, at a time when their emissions have been slowly cut back as required by the Montreal Protocol and its amendments. In general, the background concentrations of these CFCs all showed a substantial decrease in their rate of growth in the atmosphere in recent years compared to earlier years. The rates of increase for winter 1992 are 3, 9, and 2.5 pptv/yr compared to 11, 20, and 8 in 1988, for CFC-11, CFC-12, and CFC-113, respectively. Seasonal variation in global concentrations for a hydroxy-radical reactive species, tetrachloroethylene (CCl{sub 2}{double_bond}CCl{sub 2}) has also been studied.

  6. Site selection for concentrated solar thermal systems in Hawaii

    SciTech Connect

    Seki, A.

    1987-01-01

    This report identifies ares on the five major islands (Oahu, Maui, Molakai, Hawaii, and Kauai) that have the potential for concentrating solar thermal applications. The locations are based on existing solar insolation (mostly global and some direct normal) data, other meteorological information, land use, potential end-use, and existing facilities. These areas are: - Western coast of Oahu, especially near Kahe Point - Maui plains area - South-Central Molokai - Kona coast of the Big Island, especially Natural Energy Laboratory of Hawaii - Western and southern areas of Kauai. Monitoring stations are recommended at some of these sites to obtain direct normal insolation data for future evaluation.

  7. 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

  8. 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)).

  9. Selective spectral filtration with nanoparticles for concentrating solar collectors

    NASA Astrophysics Data System (ADS)

    DeJarnette, Drew; Otanicar, Todd; Brekke, Nick; Hari, Parameswar; Roberts, Kenneth

    2015-01-01

    A spectral fluid filter for potential use in hybrid photovoltaic/thermal concentrating solar collectors has been developed, targeting maximum absorption above and transmission below a desired wavelength. In this application, the temperature-dependent bandgap of the potential solar cell is used in the optimization of the filter. Dispersing a mix of colloidal nanoparticles in a heat transfer fluid is shown to absorb 86% of sub-bandgap insolation while absorbing only 18% above bandgap insolation. Transmission above bandgap light would be directly absorbed into the photovoltaic (PV) cell while absorbed photons transfer energy directly into the heat transfer fluid ultimately reducing the number of heat transfer steps. Placement of a filter in front of the PV cell is shown to decrease losses by converting an additional 2% of the total solar energy into thermal energy since it allows recollection of light reflected off the receiver.

  10. 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.

  11. 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.

  12. 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.

  13. Mass concentration in a nonlocal model of clonal selection.

    PubMed

    Busse, J-E; Gwiazda, P; Marciniak-Czochra, A

    2016-10-01

    Self-renewal is a constitutive property of stem cells. Testing the cancer stem cell hypothesis requires investigation of the impact of self-renewal on cancer expansion. To better understand this impact, we propose a mathematical model describing the dynamics of a continuum of cell clones structured by the self-renewal potential. The model is an extension of the finite multi-compartment models of interactions between normal and cancer cells in acute leukemias. It takes a form of a system of integro-differential equations with a nonlinear and nonlocal coupling which describes regulatory feedback loops of cell proliferation and differentiation. We show that this coupling leads to mass concentration in points corresponding to the maxima of the self-renewal potential and the solutions of the model tend asymptotically to Dirac measures multiplied by positive constants. Furthermore, using a Lyapunov function constructed for the finite dimensional counterpart of the model, we prove that the total mass of the solution converges to a globally stable equilibrium. Additionally, we show stability of the model in the space of positive Radon measures equipped with the flat metric (bounded Lipschitz distance). Analytical results are illustrated by numerical simulations.

  14. Optimal Concentration Configuration of Consecutive Chemical Reaction A ⇔ B ⇔ C for Minimum Entropy Generation

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Chen, Lingen; Xia, Shaojun; Sun, Fengrui

    2016-10-01

    A consecutive chemical reaction A Leftrightarrow B Leftrightarrow C is studied in this paper. The optimal concentration configuration of the reaction for minimum entropy generation with fixed yield of aimed product B is derived. The optimal concentration configuration with different initial conditions and the optimal initial concentration {C_{C0}}_{{{, opt}}} of the by-product C are obtained numerically. Compared with the control method that the concentration of A increases linearly, the entropy production is reduced by more than 90 %. The minimum entropy generation and optimal configuration of elementary reaction A Leftrightarrow B are studied by using variational method and nonlinear programming method. The validity of the nonlinear programming method is verified. The reaction rate of elementary reaction A Leftrightarrow B is in proportion to the square root of the concentration of A when entropy generation of the reaction process is minimum. The results obtained can help one to find the realizable regimes for a chemical reactor.

  15. Efficiency of including first-generation information in second-generation ranking and selection: results of computer simulation.

    Treesearch

    T.Z. Ye; K.J.S. Jayawickrama; G.R. Johnson

    2006-01-01

    Using computer simulation, we evaluated the impact of using first-generation information to increase selection efficiency in a second-generation breeding program. Selection efficiency was compared in terms of increase in rank correlation between estimated and true breeding values (i.e., ranking accuracy), reduction in coefficient of variation of correlation...

  16. 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.

  17. Wide Range Concentration Control of Dielectric Barrier Discharge Generated Ozone for Soil Sterilization

    NASA Astrophysics Data System (ADS)

    Ebihara, Kenji; Takayama, Masahiro; Strycewska, Henryka Danuta; Ikegami, Tomoaki; Gyoutoku, Yutaka; Tachibana, Masahiro

    We have developed ozone (O3) generation system suitable to soil sterilization. Wide range concentration control of O3 is required for the sterilization treatment depending on the soil property and plant growth. The dielectric barrier discharges using electrode such as Pyramid type is studied. Surface discharges are also applied to generate high concentration for quick sterilization of the agricultural soil. The treated soil properties under ozone sterilization were evaluated using pH and electrical conductivity. It is shown that ozone distribution in the soil is controlled mostly by the conditions such as concentration and flow rate as well as soil conditions of moisture and compositions.

  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. The dependence of radiolytic H2 generation of the nitrate concentration in high-level solutions

    SciTech Connect

    Walker, D.D.; Bibler, N.E.

    1991-11-19

    The rate at which hydrogen is produced from the radiolysis of high-activity waste solutions depends on the radiation dose rate to the solution and the concentration of nitrate ion in solution. At a constant dose rate, the hydrogen generation rate decreases as the nitrate ion concentration increases. Using previously measured rates of hydrogen production, an equation has been derived which calculates the hydrogen generation rate when the nitrate ion concentration is known. The hydrogen generation rate from this equation can be used to more accurately predict hydrogen production in waste tanks than is currently obtained assuming a fixed generation rate. The current fixed rate underestimates the hydrogen produced in dilute waste solutions.

  20. 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...

  1. 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...

  2. Extraction of uranium from soil using selective chelators with secondary concentration using water soluble polymers

    SciTech Connect

    Duran, B.L.; Ehler, D.S.; Sauer, N.N.

    1997-12-31

    Studies have investigated the extraction and recovery of uranium from contaminated soil containing both sorbed and metallic uranium. Our goal was to selectively bind and recover uranium from this soil and minimize secondary waste generation. Our approach was to determine optimal chelators for uranium extraction using contaminated soil taken from an area at LANL where open air testing of explosives containing depleted uranium was conducted. Uranium concentrations range in the soil from 1000-5000ppm. We have found that equimolar carbonate/bicarbonate solution in conjunction with an oxidant, sodium hypochlorite, is an excellent extractant for uranium from this soil, removing 90+% of the uranium. Our present focus is on the recovery and concentration of uranium from the extractant solution using a large water soluble polymer (>10,000 MW) as a secondary chelator for complexing the extracted uranium:carbonate complex. Using ultrafiltration, the volume of waste can be reduced 100+ fold. These commercially available polymers can then be regenerated and re-used. Using this approach, we are able to recover 90+% of the uranium in a minimal volume.

  3. Evaluation of power block arrangements for 100MW scale concentrated solar thermal power generation using top-down design

    NASA Astrophysics Data System (ADS)

    Post, Alexander; Beath, Andrew; Sauret, Emilie; Persky, Rodney

    2017-06-01

    Concentrated solar thermal power generation poses a unique situation for power block selection, in which a capital intensive heat source is subject to daily and seasonal fluctuations in intensity. In this study, a method is developed to easily evaluate the favourability of different power blocks for converting the heat supplied by a concentrated solar thermal plant into power at the 100MWe scale based on several key parameters. The method is then applied to a range of commercially available power cycles that operate over different temperatures and efficiencies, and with differing capital costs, each with performance and economic parameters selected to be typical of their technology type, as reported in literature. Using this method, the power cycle is identified among those examined that is most likely to result in a minimum levelised cost of energy of a solar thermal plant.

  4. In vitro selective antibiotic concentrations of beta-lactams for penicillin-resistant Streptococcus pneumoniae populations.

    PubMed Central

    Negri, M C; Morosini, M I; Loza, E; Baquero, F

    1994-01-01

    Therapeutic regimens containing beta-lactam antibiotics are selecting penicillin-resistant Streptococcus pneumoniae populations all over the world. The selective pressure after 4 h of exposure to different concentrations of amoxicillin, cefixime, cefuroxime, and cefotaxime for low-level or high-level penicillin-resistant S. pneumoniae was evaluated in an in vitro model with mixed populations with penicillin susceptibilities of 0.015, 0.5, 1, and 2 micrograms/ml. The antibiotic concentration selecting for low-level resistance strongly reduced the susceptible population. Increasing antibiotic concentrations tended to decrease the total proportion of penicillin-resistant bacteria because of reduced numbers of the low-level-resistant population. The antibiotic concentration selecting for high-level resistance produced fewer resistant populations, but most of the organisms selected represented high-level resistance. In general, amoxicillin was a good selector for the low-level-resistant population and a poor selector for high-level resistance; cefuroxime and cefotaxime were poor selectors for low-level resistance and better selectors than amoxicillin for high-level penicillin resistance. Cefixime was the best selector of low-level penicillin resistance. When only resistant populations were mixed, the strains with high-level resistance were selected even at low antibiotic concentrations. Determination of the effects of selective antibiotic concentrations on mixed cultures of bacteria expressing different antibiotic resistance levels may help researchers to understand the ecology and epidemiology of penicillin-resistant S. pneumoniae populations. PMID:8141563

  5. An Evolutionary Algorithm to Generate Ellipsoid Detectors for Negative Selection

    DTIC Science & Technology

    2005-03-21

    Von Zuben [21] have both implemented an AIS using the network immune model. Timmis and Neal [91] applied the model to unsupervised machine learning...and de Castro and Von Zuben [21] applied the model to the problem of clustering and filtering unlabelled numerical data sets. Danger theory is young in...algorithm, clonal selection, is described in the next section. 2.6.1 Clonal Selection. De Castro and Von Zuben produced a clonal selection algorithm

  6. Selection of resistance at lethal and non-lethal antibiotic concentrations.

    PubMed

    Hughes, Diarmaid; Andersson, Dan I

    2012-10-01

    Much of what we currently know about the genetics and evolution of antibiotic-resistance is based on selections with lethal drug concentrations that allow the detection of rare mutants with strong phenotypes. These data may be misleading with regard to the evolution of antibiotic resistance in natural environments, because bacteria are frequently exposed to concentration gradients of antibiotics. A significant part of antibiotic-resistance evolution may occur when bacteria are exposed to non-lethal concentrations of drug. High-resolution competition assays show that resistance mutations are rapidly enriched, and selected de novo, at very low antibiotic concentrations. Genomic analysis is providing a better understanding of how frequent and small-effect mutations selected at very low antibiotic concentrations contribute to the step-wise development of antibiotic resistance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. [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.

  8. 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.

  9. 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.

  10. Serum concentrations of selected persistent organic pollutants in a sample of pregnant females and changes in their concentrations during gestation.

    PubMed

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

    2009-08-01

    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. 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. The chemicals with >or= 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. 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 and emission. The redistribution of body burden for

  11. Fixed solar concentrator-collector-satelite receiver and co-generator

    SciTech Connect

    Meckler, M.

    1985-01-01

    An insolation and micro wave receiver fixedly installed in alignment with the suns azimuth and within the look angle of a satellite, and comprised of holographic windows recorded according to time related to the suns position as zone plates to concentrate infrared light into a Rankine cycle power generating receiver and to columnate ultraviolet light onto a photo voltaic power generating plane, utilizing a micro wave dish as the substrate support of photo voltaic cells and as a condenser of the Rankine cycle operating an induction generator synchronous with an external alternating current power system, and with the photo voltaic power synchronized therewith by commutation.

  12. Dependence of third-harmonic generation on melanin concentration in solution

    NASA Astrophysics Data System (ADS)

    Su, Tung-Yu; Liao, Chien-Sheng; Yang, Chih-Yuan; Zhuo, Zong-Yan; Chen, Szu-Yu; Chu, Shi-Wei

    2011-03-01

    In this study, we performed theoretical analysis and experimental measurement of third harmonic generation (THG) in melanin solution with different concentrations. As predicted by theory, only THG at glass/solution interface was observed due to Guoy phase shift effect. We have shown that this interfacial THG intensity is strongly affected by index matching condition between the two media, leading to minimal THG at a certain melanin concentration. By fitting the dependence of THG intensity versus melanin concentration, linear and nonlinear electric susceptibilities of melanin are obtained, providing a valuable tool to characterize optical properties of biological molecules.

  13. Multivariate correlation between concentrations of selected herbicides and derivatives in outflows from selected U.S. midwestern reservoirs

    USGS Publications Warehouse

    Tauler, R.; Barcelo, D.; Thurman, E.M.

    2000-01-01

    Multivariate correlations between the concentrations of selected herbicides and herbicide derivatives in outflows from selected reservoirs in the Midwestern United States for April 1992 through September 1993 were investigated using principal component analysis (PCA) and multivariate curve resolution (MCR). Two independent sources for alachlor ethanesulfonic acid, one major source related to spring flush and seasonal runoff and another minor source related to groundwater, were identified using PCA. Results of MCR provided a semiquantitative interpretation of the environmental sources of the observed herbicide concentrations in reservoir outflows and allowed the examination of their temporal and geographical distributions. Samples with higher herbicide concentrations were collected from reservoirs in Indiana and Ohio, especially during the late spring and summer.

  14. Medical waste generation in selected clinical facilities in Taiwan.

    PubMed

    Cheng, Y W; Li, K-C; Sung, F C

    2010-01-01

    This study investigated the type and amount of medical waste generated from small clinical facilities in Taiwan. We sampled 200 small medical establishments, with few or no patient beds, to survey the wastes generated and disposed. The surveyed medical facilities consisted of four groups including private clinics, medical laboratories, blood centers and public clinics. Private clinics providing surgical, dental, obstetrical, and dialysis services were included in this survey because they may generate higher amounts of infectious waste than other specialties. The overall mean general waste production rate was 3.97 kg/bed/day (or 0.075 kg/patient/day) at all the surveyed facilities, higher than that obtained from larger hospitals in Taiwan, which ranged from 2.41 to 3.26 kg/bed/day. The highest amount of infectious wastes generated among the four groups of facilities were from blood centers (3.14 kg/bed/day), followed by private clinics, medical laboratories and public clinics (1.91, 1.07, and 0.053 kg/bed/day, respectively). The overall average was 2.08 kg/bed/day. This study suggests that the waste generated at small medical facilities ranged widely.

  15. 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.

  16. A prototypic microfluidic platform generating stepwise concentration gradients for real-time study of cell apoptosis.

    PubMed

    Dai, Wen; Zheng, Yizhe; Luo, Kathy Qian; Wu, Hongkai

    2010-04-16

    This work describes the development of a prototypic microfluidic platform for the generation of stepwise concentration gradients of drugs. A sensitive apoptotic analysis method is integrated into this microfluidic system for studying apoptosis of HeLa cells under the influence of anticancer drug, etoposide, with various concentrations in parallel; it measures the yellow fluorescent proteincyan fluorescent protein fluorescence resonance energy transfer (FRET) signal that responds to the activation of caspase-3, an indicator of cell apoptosis. Sets of microfluidic valves on the chip generate stepwise concentration gradient of etoposide in various cell-culture microchambers. The FRET signals from multiple chambers are simultaneously monitored under a fluorescent microscope for long-time observation and the on-chip results are compared with those from 96-well plate study and the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The microfluidic platform shows several advantages including high-throughput capacity, low drug consumption, and high sensitivity.

  17. Ozone generated by air purifier in low concentrations: friend or foe?

    PubMed

    Cestonaro, Larissa Vivan; Marcolan, Ana Maria; Rossato-Grando, Luciana Grazziotin; Anzolin, Ana Paula; Goethel, Gabriela; Vilani, Angélica; Garcia, Solange Cristina; Bertol, Charise Dallazem

    2017-08-16

    Ozone helps decontamination environments due to its oxidative power, however present toxicity when it is in high concentrations, by long periods of exposition. This study aimed to assess the safety of ozone generator air purifier at concentrations of 0.05 ppm in rats exposed to 3 and 24 h/day for 14 and 28 days. No significant differences are observed between groups in clinical signs, feed and water intake, relative body weight gain and relative weight of organs, macroscopy and microscopy of lungs, and oxidative plasma assay. In this exposure regime, ozone does not cause genotoxicity and no significant changes in pulmonary histology indicative of toxicity. Ozone generated in low concentrations, even in exposure regimes above the recommended is safe, both acute and sub-acute exposition.

  18. Concentrating-solar biomass gasification process for a 3rd generation biofuel.

    PubMed

    Hertwich, Edgar G; Zhang, Xiangping

    2009-06-01

    A new concept of producing synfuel from biomass using concentrating solar energy as its main energy source is proposed in this paper. The aim of the concept is to obtain an easy to handle fuel with near-zero CO2 emission and reduced land-use requirements compared to first and second generation biofuels. The concept's key feature is the use of high-temperature heat from a solar concentrating tower to drive the chemical process of converting biomassto a biofuel, obtaining a near-complete utilization of carbon atoms in the biomass. H2 from water electrolysis with solar power is used for reverse water gas shift to avoid producing CO2 during the process. In a chemical process simulation, we compare the solar biofuel concept with two other advanced synfuel concepts: second generation biofuel and coal-to-liquid, both using gasification technology and capture and storage of CO2 generated in the fuel production. The solar-driventhird generation biofuel requires only 33% of the biomass input and 38% of total land as the second generation biofuel, while still exhibiting a CO2-neutral fuel cycle. With CO2 capture, second generation biofuel would lead to the removal of 50% of the carbon in the biomass from the atmosphere. There is a trade-off between reduced biomass feed costs and the increased capital requirements for the solar-driven process; it is attractive at intermediate biomass and CO2 prices.

  19. State-selective generation of molecular ions via Rydberg states

    NASA Astrophysics Data System (ADS)

    Grimes, David; Zhou, Yan; Barnum, Timothy; Coy, Stephen; Kay, Jeffrey; Field, Robert

    2014-05-01

    Autoionizing Rydberg states of molecules in the range n = 30-50 have the potential to enable the production of single quantum state selected ensembles of molecular ions, which have uses from spectroscopy to high precision measurements of fundamental constants. Multichannel Quantum Defect Theory (MQDT) fully describes the Rydberg states of molecules and the dynamics of autoionization. We have used our full MQDT description of CaF to determine optimal autoionizing resonances for producing a variety of selected rotation-vibration states of the ion. Progress towards experimental demonstrations in BaF will also be discussed. This work was supported by the NSF and an NDSEG Fellowship

  20. An Entropic Mechanism of Generating Selective Ion Binding in Macromolecules

    PubMed Central

    Thomas, Michael; Jayatilaka, Dylan; Corry, Ben

    2013-01-01

    Several mechanisms have been proposed to explain how ion channels and transporters distinguish between similar ions, a process crucial for maintaining proper cell function. Of these, three can be broadly classed as mechanisms involving specific positional constraints on the ion coordinating ligands which arise through: a “rigid cavity”, a ‘strained cavity’ and ‘reduced ligand fluctuations’. Each operates in subtly different ways yet can produce markedly different influences on ion selectivity. Here we expand upon preliminary investigations into the reduced ligand fluctuation mechanism of ion selectivity by simulating how a series of model systems respond to a decrease in ligand thermal fluctuations while simultaneously maintaining optimal ion-ligand binding distances. Simple abstract-ligand models, as well as simple models based upon the ion binding sites in two amino acid transporters, show that limiting ligand fluctuations can create ion selectivity between Li+, Na+ and K+ even when there is no strain associated with the molecular framework accommodating the different ions. Reducing the fluctuations in the position of the coordinating ligands contributes to selectivity toward the smaller of two ions as a consequence of entropic differences. PMID:23468604

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

    USDA-ARS?s Scientific Manuscript database

    Six years after the introduction of genomic selection in the US it is now possible to evaluate the impact of this technology on the population and compare those estimates to theoretical expectations. Selection differentials (SD) and generation intervals (GI) were characterized in a four-path selecti...

  2. 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.

  3. The effect of plasma antithrombin concentration on thrombin generation and fibrin gel structure.

    PubMed

    Elgue, G; Sanchez, J; Fatah, K; Olsson, P; Blombäck, B

    1994-07-15

    Congenital deficiency of antithrombin (AT) is associated with thrombotic events and AT consumption occurs in some severe disorders and after treatment with heparin. The aim of this study was to investigate whether variations in the level of plasma AT modify thrombin generation and the fibrin formation process after the intrinsic coagulation mechanism is triggered. Normal plasma was depleted of AT by immunoadsorption on CNBr-Sepharose coupled with the anti-AT-IgG fraction of antiserum. The AT-depleted plasma was reconstituted with AT (between 0.3 and 1.5 AT units per ml). Thrombin generation was measured as the development of thrombin-antithrombin complexes (TAT). The lag phase preceding fibrin formation depended on the concentration of AT. The short lag phase was seen in completely AT-depleted plasma and the long in plasma with 1.5 AT units per ml. TAT generation, determined in parallel consecutive samples, showed that the rate at which thrombin was generated was inverse to the AT concentration in plasma. The network structure of hydrated fibrin gels in the clotted plasma was studied by measuring the wavelength dependence of gel turbidity. The mass/length ratio value, -i.e. the thickness of fiber strands and porosity of the gel increased with increasing AT concentrations. It is concluded that plasma AT regulates the rate of prothrombin-thrombin conversion, the clotting time and the consequently network structure of the fibrin gel.

  4. Radioactivity concentration in liquid and solid phases of scale and sludge generated in the petroleum industry.

    PubMed

    Paranhos Gazineu, Maria Helena; de Araújo, Andressa Arruda; Brandão, Yana Batista; Hazin, Clovis Abrahão; de O Godoy, José Marcos

    2005-01-01

    Scales and sludge generated during oil extraction and production can contain uranium, thorium, radium and other natural radionuclides, which can cause exposure of maintenance personnel. This work shows how the oil content can influence the results of measurements of radionuclide concentration in scale and sludge. Samples were taken from a PETROBRAS unit in Northeast Brazil. They were collected directly from the inner surface of water pipes or from barrels stored in the waste storage area of the E&P unit. The oil was separated from the solids with a Soxhlet extractor by using aguarras at 90+/-5 degrees C as solvent. Concentrations of 226Ra and 228Ra in the samples were determined before and after oil extraction by using an HPGe gamma spectrometric system. The results showed an increase in the radionuclide concentration in the solid (dry) phase, indicating that the above radionuclides concentrate mostly in the solid material.

  5. [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%.

  6. Fabrication Processes to Generate Concentration Gradients in Polymer Solar Cell Active Layers.

    PubMed

    Inaba, Shusei; Vohra, Varun

    2017-05-09

    Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor. In this review, we relate processes to generate active layers with ED-EA vertical concentration gradients. After summarizing the formation of such concentration gradients in single layer active layers through processes such as annealing or additives, we will verify that sequential deposition of multilayered active layers can be an efficient approach to remarkably increase the fill factor and PCE of PSCs. In fact, applying this challenging approach to fabricate inverted architecture PSCs has the potential to generate low-cost, high efficiency and stable devices, which may revolutionize worldwide energy demand and/or help develop next generation devices such as semi-transparent photovoltaic windows.

  7. Fabrication Processes to Generate Concentration Gradients in Polymer Solar Cell Active Layers

    PubMed Central

    Inaba, Shusei; Vohra, Varun

    2017-01-01

    Polymer solar cells (PSCs) are considered as one of the most promising low-cost alternatives for renewable energy production with devices now reaching power conversion efficiencies (PCEs) above the milestone value of 10%. These enhanced performances were achieved by developing new electron-donor (ED) and electron-acceptor (EA) materials as well as finding the adequate morphologies in either bulk heterojunction or sequentially deposited active layers. In particular, producing adequate vertical concentration gradients with higher concentrations of ED and EA close to the anode and cathode, respectively, results in an improved charge collection and consequently higher photovoltaic parameters such as the fill factor. In this review, we relate processes to generate active layers with ED–EA vertical concentration gradients. After summarizing the formation of such concentration gradients in single layer active layers through processes such as annealing or additives, we will verify that sequential deposition of multilayered active layers can be an efficient approach to remarkably increase the fill factor and PCE of PSCs. In fact, applying this challenging approach to fabricate inverted architecture PSCs has the potential to generate low-cost, high efficiency and stable devices, which may revolutionize worldwide energy demand and/or help develop next generation devices such as semi-transparent photovoltaic windows. PMID:28772878

  8. Testing, Selection, and Implementation of Random Number Generators

    DTIC Science & Technology

    2008-07-01

    U.S. Army Research Laboratory ATTN: AMSRD-ARL-SL-BD Aberdeen Proving Ground, MD 21005-5068 8 . PERFORMING ORGANIZATION REPORT NUMBER ARL...NUMBER (Include area code) 410-278-6832 Standard Form 298 (Rev. 8 /98) Prescribed by ANSI Std. Z39.18 ii Contents 1. Random Number Generators 1...Linear RNGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.4.2 The Characteristic Polynomial

  9. 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

  10. 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.

  11. 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…

  12. 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…

  13. 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

    2016-04-05

    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.

  14. In vitro selection of resistance in Escherichia coli and Klebsiella spp. at in vivo fluoroquinolone concentrations

    PubMed Central

    2010-01-01

    Background Fluoroquinolones are potent antimicrobial agents used for the treatment of a wide variety of community- and nosocomial- infections. However, resistance to fluoroquinolones in Enterobacteriaceae is increasingly reported. Studies assessing the ability of fluoroquinolones to select for resistance have often used antimicrobial concentrations quite different from those actually acquired at the site of infection. The present study compared the ability to select for resistance of levofloxacin, ciprofloxacin and prulifloxacin at concentrations observed in vivo in twenty strains of Escherichia coli and Klebsiella spp. isolated from patients with respiratory and urinary infections. The frequencies of spontaneous single-step mutations at plasma peak and trough antibiotic concentrations were calculated. Multi-step selection of resistance was evaluated by performing 10 serial cultures on agar plates containing a linear gradient from trough to peak antimicrobial concentrations, followed by 10 subcultures on antibiotic-free agar. E. coli resistant strains selected after multi-step selection were characterized for DNA mutations by sequencing gyrA, gyrB, parC and parE genes. Results Frequencies of mutations for levofloxacin and ciprofloxacin were less than 10-11 at peak concentration, while for prulifloxacin they ranged from <10-11 to 10-5. The lowest number of resistant mutants after multistep selection was selected by levofloxacin followed by ciprofloxacin and prulifloxacin. Both ciprofloxacin- and prulifloxacin-resistant mutants presented mutations in gyrA and parC, while levofloxacin resistance was found associated only to mutations in gyrA. Conclusions Among the tested fluoroquinolones, levofloxacin was the most capable of limiting the occurrence of resistance. PMID:20409341

  15. 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.

  16. Rapid selection of organisms with increasing resistance on subinhibitory concentrations of norfloxacin in agar.

    PubMed Central

    Tenney, J H; Maack, R W; Chippendale, G R

    1983-01-01

    Serial passage of Pseudomonas aeruginosa ATCC 27853 or Escherichia coli ATCC 25922 on agar with subinhibitory concentrations of norfloxacin rapidly produced isolates with minimal inhibitory concentrations (MICs) of norfloxacin up to 512-fold higher than that for the original strain. Although MICs of seven unrelated antibiotics were unchanged, increasing MICs occurred in parallel with norfloxacin, cinoxacin, and nalidixic acid regardless of which of these three organic acids was used to select for increased resistance. P. aeruginosa with a norfloxacin MIC of greater than 256 micrograms/ml could be selected; however, E. coli with MICs greater than the clinically achievable level of 16 micrograms/ml could not be produced. PMID:6219620

  17. 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 .

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

    DOE PAGES

    Garcia, Andres; Wang, Jing; Windus, Theresa L.; ...

    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.

  19. 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

  20. 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 ...

  1. 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 ...

  2. Selective carboxylate production by controlling hydrogen, carbon dioxide and substrate concentrations in mixed culture fermentation.

    PubMed

    Arslan, D; Steinbusch, K J J; Diels, L; De Wever, H; Hamelers, H V M; Buisman, C J N

    2013-05-01

    This research demonstrated the selective production of n-butyrate from mixed culture by applying 2 bar carbon dioxide into the headspace of batch fermenters or by increasing the initial substrate concentration. The effect of increasing initial substrate concentration was investigated at 8, 13.5 and 23 g COD/L with potato processing waste stream. Within 1 week of incubation, n-butyrate fraction selectively increased up to 83% by applying 2 bar hydrogen or 78% by applying carbon dioxide into the headspace whereas it was only 59% in the control reactor. Although the fraction of n-butyrate was elevated, the concentration remained lower than in the control. Both the highest concentration and fraction of n-butyrate were observed under the highest initial substrate concentration without headspace addition. The concentration was 10 g COD/L with 73% fraction. The operational conditions obtained from batch experiments for selective n-butyrate production were validated in a continuous process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Optimization research on the concentration field of NO in selective catalytic reduction flue gas denitration system

    NASA Astrophysics Data System (ADS)

    Zheng, Qingyu; Zhang, Guoqiang; Che, Kai; Shao, Shikuan; Li, Yanfei

    2017-08-01

    Taking 660 MW generator unit denitration system as a study object, an optimization and adjustment method shall be designed to control ammonia slip, i.e. adjust ammonia injection system based on NO concentration distribution at inlet/outlet of the denitration system to make the injected ammonia distribute evenly. The results shows that, this method can effectively improve NO concentration distribution at outlet of the denitration system and decrease ammonia injection amount and ammonia slip concentration. Reduce adverse impact of SCR denitration process on the air preheater to realize safe production by guaranteeing that NO discharge shall reach the standard.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  5. 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

  6. 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.

  7. 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.

  8. 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).

  9. 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.

  10. 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.

  11. 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.

  12. High-concentration ozone generator for oxidation of silicon operating at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Koike, Kunihiko; Fukuda, Tatsuo; Ichimura, Shingo; Kurokawa, Akira

    2000-11-01

    A high-concentration ozone generator operating at atmospheric pressure was developed to produce ozone for use in fabrication of ultrathin silicon oxide films. A technique for adsorption onto silica gel, in which ozone has adsorption priority over oxygen, was adopted to obtain concentrated ozone. An ozone-oxygen mixture gas generated by a commercial ozonizer is fed in turn to three parallel adsorption columns that are kept at -60 °C. After the adsorption process, the ozone-enriched gas is desorbed by a slow warming of the columns from -60 to 0 °C and is stored in a storage vessel. Finally, the condensed ozone, at concentrations up to 30 vol % can be supplied continuously to a silicon oxidation chamber at atmospheric pressure and a constant flow rate. Moreover, highly concentrated ozone above 70 vol % can be produced in a batch process by using an additional purification procedure prior to the desorption. We confirmed that even with 25 vol % ozone gas, SiO2 film as thick as 6.3 nm grew on a Si substrate at 600 °C and 15 Torr in a 30 min exposure, while under the same experimental conditions only a 3.1 nm thick SiO2 film could be formed on the same substrate with pure oxygen.

  13. 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.

  14. Prediction and validation of concentration gradient generation in a paper-based microfluidic channel

    NASA Astrophysics Data System (ADS)

    Jang, Ilhoon; Kim, Gang-June; Song, Simon

    2016-11-01

    A paper-based microfluidic channel has obtained attention as a diagnosis device that can implement various chemical or biological reactions. With benefits of thin, flexible, and strong features of paper devices, for example, it is often utilized for cell culture where controlling oxygen, nutrients, metabolism, and signaling molecules gradient affects the growth and movement of the cells. Among various features of paper-based microfluidic devices, we focus on establishment of concentration gradient in a paper channel. The flow is subject to dispersion and capillary effects because a paper is a porous media. In this presentation, we describe facile, fast and accurate method of generating a concentration gradient by using flow mixing of different concentrations. Both theoretical prediction and experimental validation are discussed along with inter-diffusion characteristics of porous flows. This work was supported by the National Research Foundation of Korea(NRF) Grant funded by the Korea government(MSIP) (No. 2016R1A2B3009541).

  15. New concepts in antimicrobial susceptibility testing: the mutant prevention concentration and mutant selection window approach.

    PubMed

    Blondeau, Joseph M

    2009-10-01

    Current measurements of antimicrobial susceptibility or resistance utilize a standardized bacterial inoculum (10(5) cfu/mL) exposed to varying drug concentrations in a test tube. Following incubation under ideal conditions, the lowest drug concentration inhibiting growth is the minimum inhibitory concentration (MIC). When the MIC exceeds the amount of drug that can be safely achieved in the body, we call these microorganisms resistant; established breakpoints for various 'bug-drug' combinations are used to categorize microorganisms as susceptible, intermediate or resistant. MIC testing has been used for decades to guide antimicrobial therapy and remains an important measurement for infectious diseases. More recently, the mutant prevention concentration (MPC) has been described as a novel measurement of in vitro susceptibility or resistance and is based on the testing of larger bacterial inocula, i.e. > or =10(9) cfu/mL - such as those associated with some infections in humans and animals. MPC defines the lowest drug concentration required to block the growth of the least susceptible cell present in high density bacterial populations. MPC testing applies to microorganisms considered susceptible to the drug by MIC testing. The mutant selection window (MSW) defines the 'danger zone' for therapeutic drug concentrations. Minimizing the length of time the drug concentration remains in the MSW may reduce the likelihood for resistance selection during therapy. The MSW is bordered by the MIC and MPC values and the drug concentration range between the measured MIC and MPC values defines the MSW. MPC values, when considered with drug pharmacology, may allow prediction on the probability of resistance selection when bacteria are exposed to antimicrobial agents during therapy for infectious diseases. In today's environment, resistance prevention should be a goal of antimicrobial therapy.

  16. 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.

  17. The selection of creative ideas after individual idea generation: choosing between creativity and impact.

    PubMed

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

    2010-02-01

    It is commonly assumed that successful innovation depends on creative idea generation: the more ideas are generated, the higher the probability of selecting a very good idea should be. However, research has shown that people do not perform optimally at idea selection and that ideational output may not contribute much to creative idea selection. The present studies aim to explain this phenomenon. We identified the strong tendency of our participants to select feasible and desirable ideas, at the cost of originality, as the main reason for their poor selection performance. Two manipulations of participants' processing of the available ideas (exclusion instructions and quality ratings) had no effect on selection effectiveness. In contrast, explicitly instructing participants to select creative or original ideas did improve selection effectiveness with regard to idea originality, but at the same time decreased participants' satisfaction and the rated effectiveness of chosen ideas. Results are discussed in relation to an effectiveness-originality trade off.

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

    NASA Astrophysics Data System (ADS)

    Motallebi, Sadegh; Aliakbary, Sadegh; Habibi, Jafar

    2013-12-01

    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.

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

    PubMed

    Motallebi, Sadegh; Aliakbary, Sadegh; Habibi, Jafar

    2013-12-01

    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.

  20. 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.

  1. Dynamics of Total Microcystin LR Concentration in Three Subtropical Hydroelectric Generation Reservoirs in Uruguay, South America.

    PubMed

    González-Piana, Mauricio; Fabián, Daniel; Piccardo, Andrea; Chalar, Guillermo

    2017-08-20

    This study analyzed the temporal dynamics of total microcystin LR concentrations between the years of 2012 and 2015 in the Bonete, Baygorria and Palmar hydroelectric generation reservoirs in the central region of the Negro River, Uruguay. The three reservoirs showed differents total microcystin LR concentration, with no significant differences among them. Over 20 sampling dates, the three reservoirs exhibited total microcystin LR concentrations on eight occasions that corresponded to a slight to moderate human health risk according to WHO guideline values for recreational waters. By determining the concentration of microcystin LR in cyanobacterial biomass, we identified cyanobacterial populations that occurred over time with varying degrees of toxin production (maximal 85.4 µg/mm(3)). The microcystin LR concentration in Bonete was positively correlated with temperature (r = 0.587) and cyanobacterial biomass (r = 0.736), in Baygorria with cyanobacterial biomass (r = 0.521), and in Palmar with temperature (r = 0.500) and negatively correlated with ammonia (r = -0.492). Action is needed to reduce the presence of toxic cyanobacteria in these systems. A decrease in the use of agrochemicals and management changes in the reservoir basins could be successful long-term measures.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Generation of high-titer viral preparations by concentration using successive rounds of ultracentrifugation

    PubMed Central

    2011-01-01

    Background Viral vectors provide a method of stably introducing exogenous DNA into cells that are not easily transfectable allowing for the ectopic expression or silencing of genes for therapeutic or experimental purposes. However, some cell types, in particular bone marrow cells, dendritic cells and neurons are difficult to transduce with viral vectors. Successful transduction of such cells requires preparation of highly concentrated viral stocks, which permit a high virus concentration and multiplicity of infection (MOI) during transduction. Pseudotyping with the vesicular stomatitis virus G (VSV-G) envelope protein is common practice for both lentiviral and retroviral vectors. The VSV-G glycoprotein adds physical stability to retroviral particles, allowing concentration of virus by high-speed ultracentrifugation. Here we describe a method report for concentration of virus from large volumes of culture supernatant by means of successive rounds of ultracentrifugation into the same ultracentrifuge tube. Method Stable retrovirus producer cell lines were generated and large volumes of virus-containing supernatant were produced. We then tested the transduction ability of virus following varying rounds of concentration by ultra-centrifugation. In a second series of experiments lentivirus-containing supernatant was produced by transient transfection of 297T/17 cells and again we tested the transduction ability of virus following multiple rounds of ultra-centrifugation. Results We report being able to centrifuge VSV-G coated retrovirus for as many as four rounds of ultracentrifugation while observing an additive increase in viral titer. Even after four rounds of ultracentrifugation we did not reach a plateau in viral titer relative to viral supernatant concentrated to indicate that we had reached the maximum tolerated centrifugation time, implying that it may be possible to centrifuge VSV-G coated retrovirus even further should it be necessary to achieve yet higher

  7. Efficiency of using first-generation information during second-generation selection: results of computer simulation.

    Treesearch

    T.Z. Ye; K.J.S. Jayawickrama; G.R. Johnson

    2004-01-01

    BLUP (Best linear unbiased prediction) method has been widely used in forest tree improvement programs. Since one of the properties of BLUP is that related individuals contribute to the predictions of each other, it seems logical that integrating data from all generations and from all populations would improve both the precision and accuracy in predicting genetic...

  8. Copper chelation selectively kills colon cancer cells through redox cycling and generation of reactive oxygen species.

    PubMed

    Fatfat, Maamoun; Merhi, Raghida Abou; Rahal, Omar; Stoyanovsky, Detcho A; Zaki, Angela; Haidar, Hazar; Kagan, Valerian E; Gali-Muhtasib, Hala; Machaca, Khaled

    2014-07-21

    Metals including iron, copper and zinc are essential for physiological processes yet can be toxic at high concentrations. However the role of these metals in the progression of cancer is not well defined. Here we study the anti-tumor activity of the metal chelator, TPEN, and define its mechanism of action. Multiple approaches were employed, including cell viability, cell cycle analysis, multiple measurements of apoptosis, and mitochondrial function. In addition we measured cellular metal contents and employed EPR to record redox cycling of TPEN-metal complexes. Mouse xenografts were also performed to test the efficacy of TPEN in vivo. We show that metal chelation using TPEN (5μM) selectively induces cell death in HCT116 colon cancer cells without affecting the viability of non-cancerous colon or intestinal cells. Cell death was associated with increased levels of reactive oxygen species (ROS) and was inhibited by antioxidants and by prior chelation of copper. Interestingly, HCT116 cells accumulate copper to 7-folds higher levels than normal colon cells, and the TPEN-copper complex engages in redox cycling to generate hydroxyl radicals. Consistently, TPEN exhibits robust anti-tumor activity in vivo in colon cancer mouse xenografts. Our data show that TPEN induces cell death by chelating copper to produce TPEN-copper complexes that engage in redox cycling to selectively eliminate colon cancer cells.

  9. Pharmacodynamic Model To Describe the Concentration-Dependent Selection of Cefotaxime-Resistant Escherichia coli

    PubMed Central

    Olofsson, Sara K.; Geli, Patricia; Andersson, Dan I.; Cars, Otto

    2005-01-01

    Antibiotic dosing regimens may vary in their capacity to select mutants. Our hypothesis was that selection of a more resistant bacterial subpopulation would increase with the time within a selective window (SW), i.e., when drug concentrations fall between the MICs of two strains. An in vitro kinetic model was used to study the selection of two Escherichia coli strains with different susceptibilities to cefotaxime. The bacterial mixtures were exposed to cefotaxime for 24 h and SWs of 1, 2, 4, 8, and 12 h. A mathematical model was developed that described the selection of preexisting and newborn mutants and the post-MIC effect (PME) as functions of pharmacokinetic parameters. Our main conclusions were as follows: (i) the selection between preexisting mutants increased with the time within the SW; (ii) the emergence and selection of newborn mutants increased with the time within the SW (with a short time, only 4% of the preexisting mutants were replaced by newborn mutants, compared to the longest times, where 100% were replaced); and (iii) PME increased with the area under the concentration-time curve (AUC) and was slightly more pronounced with a long elimination half-life (T1/2) than with a short T1/2 situation, when AUC is fixed. We showed that, in a dynamic competition between strains with different levels of resistance, the appearance of newborn high-level resistant mutants from the parental strains and the PME can strongly affect the outcome of the selection and that pharmacodynamic models can be used to predict the outcome of resistance development. PMID:16304176

  10. 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.

  11. 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.

  12. 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.

  13. A selective electrocatalyst–based direct methanol fuel cell operated at high concentrations of methanol

    PubMed Central

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-01-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm−2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol. PMID:28695199

  14. A selective electrocatalyst-based direct methanol fuel cell operated at high concentrations of methanol.

    PubMed

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-06-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm(-2) at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol.

  15. 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

  16. Induction and selection of Sox17-expressing endoderm cells generated from murine embryonic stem cells.

    PubMed

    Schroeder, Insa S; Sulzbacher, Sabine; Nolden, Tobias; Fuchs, Joerg; Czarnota, Judith; Meisterfeld, Ronny; Himmelbauer, Heinz; Wobus, Anna M

    2012-01-01

    Embryonic stem (ES) cells offer a valuable source for generating insulin-producing cells. However, current differentiation protocols often result in heterogeneous cell populations of various developmental stages. Here we show the activin A-induced differentiation of mouse ES cells carrying a homologous dsRed-IRES-puromycin knock-in within the Sox17 locus into the endoderm lineage. Sox17-expressing cells were selected by fluorescence-assisted cell sorting (FACS) and characterized at the transcript and protein level. Treatment of ES cells with high concentrations of activin A for 10 days resulted in up to 19% Sox17-positive cells selected by FACS. Isolated Sox17-positive cells were characterized by defini- tive endoderm-specific Sox17/Cxcr4/Foxa2 transcripts, but lacked pluripotency-associated Oct4 mRNA and protein. The Sox17-expressing cells showed downregulation of extraembryonic endoderm (Sox7, Afp, Sdf1)-, mesoderm (Foxf1, Meox1)- and ectoderm (Pax6, NeuroD6)-specific transcripts. The presence of Hnf4α, Hes1 and Pdx1 mRNA demonstrated the expression of primitive gut/foregut cell-specific markers. Ngn3, Nkx6.1 and Nkx2.2 transcripts in Sox17-positive cells were determined as properties of pancreatic endocrine progenitors. Immunocytochemistry of activin A-induced Sox17-positive embryoid bodies revealed coexpression of Cxcr4 and Foxa2. Moreover, the histochemical demonstration of E-cadherin-, Cxcr4-, Sox9-, Hnf1β- and Ngn3-positive epithelial-like structures underlined the potential of Sox17-positive cells to further differentiate into the pancreatic lineage. By reducing the heterogeneity of the ES cell progeny, Sox17-expressing cells are a suitable model to evaluate the effects of growth and differentiation factors and of culture conditions to delineate the differentiation process for the generation of pancreatic cells in vitro. Copyright © 2011 S. Karger AG, Basel.

  17. Generating Non-Linear Concentration Gradients in Microfluidic Devices for Cell Studies

    PubMed Central

    Selimović, Šeila; Sim, Woo Young; Kim, Sang Bok; Jang, Yun Ho; Lee, Won Gu; Khabiry, Masoud; Bae, Hojae; Jambovane, Sachin; Hong, Jong Wook; Khademhosseini, Ali

    2011-01-01

    We describe a microfluidic device for generating non-linear (exponential and sigmoidal) concentration gradients, coupled with a microwell array for cell storage and analysis. The device has two inputs for co-flowing multiple aqueous solutions, a main co-flow channel and an asymmetrical grid of fluidic channels that allows the two solutions to combine at intersection points without fully mixing. Due to this asymmetry and diffusion of the two species in the co-flow channel, varying amounts of the two solutions enter each fluidic path. This induces exponential and sigmoidal concentration gradients at low and high flow rates, respectively, making the microfluidic device versatile. A key feature of this design is that it is space-saving, as it does not require multiplexing or a separate array of mixing channels. Furthermore, the gradient structure can be utilized in concert with cell experiments, to expose cells captured in microwells to various concentrations of soluble factors. We demonstrate the utility of this design to assess the viability of fibroblast cells in response to a range of hydrogen peroxide (H2O2) concentrations. PMID:21344866

  18. Dependence of Initial Oxygen Concentration on Ozone Yield Using Inductive Energy Storage System Pulsed Power Generator

    NASA Astrophysics Data System (ADS)

    Go, Tomio; Tanaka, Yasushi; Yamazaki, Nobuyuki; Mukaigawa, Seiji; Takaki, Koichi; Fujiwara, Tamiya

    Dependence of initial oxygen concentration on ozone yield using streamer discharge reactor driven by an inductive energy storage system pulsed power generator is described in this paper. Fast recovery type diodes were employed as semiconductor opening switch to interrupt a circuit current within 100 ns. This rapid current change produced high-voltage short pulse between a secondary energy storage inductor. The repetitive high-voltage short pulse was applied to a 1 mm diameter center wire electrode placed in a cylindrical pulse corona reactor. The streamer discharge successfully occurred between the center wire electrode and an outer cylinder ground electrode of 2 cm inner diameter. The ozone was produced with the streamer discharge and increased with increasing pulse repetition rate. The ozone yield changed in proportion to initial oxygen concentration contained in the injected gas mixture at 800 ns forward pumping time of the current. However, the decrease of the ozone yield by decreasing oxygen concentration in the gas mixture at 180 ns forward pumping time of the current was lower than the decrease at 800 ns forward pumping time of the current. This dependence of the initial oxygen concentration on ozone yield at 180 ns forward pumping time is similar to that of dielectric barrier discharge reactor.

  19. Low-Concentration Ciprofloxacin Selects Plasmid-Mediated Quinolone Resistance Encoding Genes and Affects Bacterial Taxa in Soil Containing Manure

    PubMed Central

    Huang, Ting; Xu, Ying; Zeng, Jie; Zhao, Dong-Hao; Li, Liang; Liao, Xiao-Ping; Liu, Ya-Hong; Sun, Jian

    2016-01-01

    The spread of antimicrobial resistance in environment is promoted at least in part by the inappropriate use of antibiotics in animals and humans. The present study was designed to investigate the impact of different concentrations of ciprofloxacin in soil containing manure on the development of plasmid-mediated quinolone resistance (PMQR) – encoding genes and the abundance of soil bacterial communities. For these studies, high-throughput next-generation sequencing of 16S rRNA, real-time polymerase chain reaction and standard microbiologic culture methods were utilized. We demonstrated that the dissipate rate of relative abundances of some of PMQR-encoding genes, such as qnrS, oqxA and aac(6′)-Ib-cr, were significantly lower with ciprofloxacin 0.04 and 0.4 mg/kg exposure as compared to no-ciprofloxacin control and ciprofloxacin 4 mg/kg exposure during 2 month. Also, the number of ciprofloxacin resistant bacteria was significantly greater in ciprofloxacin 0.04 and 0.4 mg/kg exposure as compared with no-ciprofloxacin control and the ciprofloxacin 4 mg/kg exposure. In addition, lower ciprofloxacin concentration provided a selective advantage for the populations of Xanthomonadales and Bacillales in orders while Agrobacterium, Bacillus, Enterococcus, and Burkholderia in genera. These findings suggest that lower concentration of ciprofloxacin resulted in a slower rate of PMQR-encoding genes dissipation and selected development of ciprofloxacin-resistant bacteria in soil amended with manure. PMID:27847506

  20. Phenotypic consequences of 1,000 generations of selection at elevated CO2 in a green alga.

    PubMed

    Collins, Sinéad; Bell, Graham

    2004-09-30

    Estimates of the effect of increasing atmospheric CO2 concentrations on future global plant production rely on the physiological response of individual plants or plant communities when exposed to high CO2 (refs 1-6). Plant populations may adapt to the changing atmosphere, however, such that the evolved plant communities of the next century are likely to be genetically different from contemporary communities. The properties of these future communities are unknown, introducing a bias of unknown sign and magnitude into projections of global carbon pool dynamics. Here we report a long-term selection experiment to investigate the phenotypic consequences of selection for growth at elevated CO2 concentrations. After about 1,000 generations, selection lines of the unicellular green alga Chlamydomonas failed to evolve specific adaptation to a CO2 concentration of 1,050 parts per million. Some lines, however, evolved a syndrome involving high rates of photosynthesis and respiration, combined with higher chlorophyll content and reduced cell size. These lines also grew poorly at ambient concentrations of CO2. We tentatively attribute this outcome to the accumulation of conditionally neutral mutations in genes affecting the carbon concentration mechanism.

  1. 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. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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

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

    SciTech Connect

    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.

  4. 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...

  5. 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...

  6. 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…

  7. Fish bioconcentration studies with column-generated analyte concentrations of highly hydrophobic organic chemicals.

    PubMed

    Schlechtriem, Christian; Böhm, Leonard; Bebon, Rebecca; Bruckert, Hans-Jörg; Düring, Rolf-Alexander

    2017-04-01

    The performance of aqueous exposure bioconcentration fish tests according to Organisation for Economic Co-operation and Development (OECD) guideline 305 requires the possibility of preparing stable aqueous concentrations of the test substances. For highly hydrophobic organic chemicals (HOCs; octanol-water partition coefficient [log KOW ] > 5), testing via aqueous exposure may become increasingly difficult. A solid-phase desorption dosing system was developed to generate stable concentrations of HOCs without using solubilizing agents. The system was tested with hexachlorobenzene (HCB), o-terphenyl (oTP), polychlorinated biphenyl (PCB) 153, and dibenz[a,h]anthracene (DBA) (log KOW 5.5-7.8) in 2 flow-through fish tests with rainbow trout (Oncorhynchus mykiss). The analysis of the test media applied during the bioconcentration factor (BCF) studies showed that stable analyte concentrations of the 4 HOCs were maintained in the test system over an uptake period of 8 wk. Bioconcentration factors (L kg(-1) wet wt) were estimated for HCB (BCF 35 589), oTP (BCF 12 040), and PCB 153 (BCF 18 539) based on total water concentrations. No bioconcentration could be determined for DBA, probably because of the rapid metabolism of the test item. The solid-phase desorption dosing system is suitable to provide stable aqueous concentrations of HOCs required to determine the bioconcentration in fish and represents a viable alternative to the use of solubilizing agents for the preparation of test solutions. Environ Toxicol Chem 2017;36:906-916. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

  8. 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.

  9. Selection and concentration of obstetric facilities in Japan: Longitudinal study based on national census data.

    PubMed

    Matsumoto, Masatoshi; Koike, Soichi; Matsubara, Shigeki; Kashima, Saori; Ide, Hiroo; Yasunaga, Hideo

    2015-06-01

    A shortage of obstetricians with increased workload is a social problem in Japan. In response, the government and professional bodies have accelerated the 'selection and concentration' of obstetric facilities. The aim of this study was to evaluate the recent trend of selection and concentration. We used data on the number of deliveries and of obstetricians in each hospital and clinic in Japan, according to the Static Survey of Medical Institutions in 2005, 2008 and 2011. To evaluate the inter-facility equality of distribution of the number of deliveries, number of obstetricians and number of deliveries per obstetrician, Gini coefficients were calculated. The number of obstetric hospitals decreased by 20% and the number of deliveries per hospital increased by 26% between 2005 and 2011. Hospital obstetricians increased by 16% and the average number of obstetricians per hospital increased by 19% between 2008 and 2011. Gini coefficient of deliveries has significantly decreased. In contrast, Gini coefficient of deliveries per obstetrician has significantly increased. The degree of increase in obstetricians and of decrease in deliveries per obstetrician was largest at the hospitals with the highest proportion of cesarean sections. The proportion of obstetric hospitals with the optimal volume of deliveries and obstetricians, as defined by Japan Society of Obstetrics and Gynecology, was 4% in 2008, and it had doubled to 8.1% 3 years later. The selection and concentration of obstetric facilities is progressing rapidly and effectively in Japan. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  10. Generation of American elm trees with tolerance to Dutch elm disease through controlled crosses and selection

    Treesearch

    James M. Slavicek; Kathleen S. Knight

    2012-01-01

    The goal of our research and development efforts is to generate new and/or improved selections of the American elm (Ulmus americana L.) with tolerance/resistance to Dutch elm disease (DED). The approaches we are taking for this effort include: 1) controlled breeding using known DED -tolerant selections, 2) controlled breeding using DED-tolerant...

  11. Early generation selection results from a two year, six location study

    USDA-ARS?s Scientific Manuscript database

    In potato breeding programs, early generation selections are rarely evaluated in multiple environments because of limited seed quantities. By the time seed quantities are available, few clones remain from the original population. The purpose of this study was to allow multiple locations to select ...

  12. Selective exploitation of large pike Esox lucius--effects on mercury concentrations in fish populations.

    PubMed

    Sharma, Chhatra Mani; Borgstrøm, Reidar; Huitfeldt, Jørgen Sinkaberg; Rosseland, Bjørn Olav

    2008-07-25

    The present study outlines two main trends of mercury transfer patterns through the fish community: 1) the Hg concentrations increase with increase in the trophic level, with top predators having the highest concentrations, and 2) a fast growth rate may dilute the concentrations of Hg in fish muscle tissue (growth biodilution). In 2004, an extensive reduction in number of large pike (Esox lucius L.), was initiated by selective gillnet fishing in Lake Arungen, Norway, in order to increase the pike recruitment due to an expected reduction in cannibalism. In this connection, total mercury (THg) concentrations in the fish community were studied both before (2003) and after (2005) the removal of large pike. The delta(15)N signatures and stomach content analyses indicated that pike and perch (Perca fluviatilis L.) occupied the highest trophic position, while roach (Rutilus rutilus (L.)) was at the lower level, and rudd (Scardinius erythrophthalmus L.) at the lowest. The piscivores, pike and perch, had the highest concentrations of THg. The biomagnification rate of THg through the food web in the fish community was 0.163 (per thousand delta(15)N), with the highest uptake rate (0.232) in perch. A significant decrease in THg concentrations was found in all fish species in 2005 compared to 2003. Removal of the top predators in an Hg contaminated lake might thus be an important management tool for reducing Hg levels in fish, thereby reducing health risk to humans.

  13. 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.

  14. From electroconvective vortices to current hot spots on ion selective membranes subject to concentration polarization

    NASA Astrophysics Data System (ADS)

    Wang, Karen; Mani, Ali

    2016-11-01

    Electroconvective instabilities near ion-selective surfaces have been shown to greatly enhance ion transport and play a significant role in a wide range of applications in electrochemistry. When the driving voltage exceeds a threshold, electroconvection becomes chaotic and leads to intermittent spikes of current density on the ion-selective surface. We present an investigation of this phenomenon by considering a canonical setting consisting of a symmetric binary electrolyte next to a flat, ion-selective membrane subject to an external driving voltage. By tracking individual rolls of vortices, we reveal the common mechanism under which the three-way coupled fluid dynamics, ion transport, and electrostatic effects lead to advective displacement of ion concentration field, sustained vortices and vortex migration, and current hot spots on the membrane.

  15. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Reuse of low concentrated electronic wastewater using selected microbe immobilised cell system.

    PubMed

    Lee, Seok Jae; Lee, Yong-Woo; Chung, Jinwook; Lee, Jong Kwang; Lee, Ju Young; Jahng, Deokjin; Cha, Yongmi; Yu, Yongho

    2008-01-01

    This work describes a novel technology for the reuse of low concentrated electronic wastewater using selected microbe immobilisation cell (SMIC) system. The SMIC system is an innovative technology to maximise the activity of specific microorganisms capable of decomposing tetramethyl ammonium hydroxide (TMAH) as a major organic compound in the low concentrated electronic wastewater. The versatility of the SMIC system has been studied by using continuous-flow reactors. The TOC in a SMIC system was removed completely, indicating that SMIC is a useful technology to remove TOC biologically in low concentrated wastewater. The most important advantages of this system are highly effective and stable in view of TMAH removal. These characteristics make well suited to various applications depending on targeted compounds and microorganisms and, especially, in the wastewater of electronic facilities. (c) IWA Publishing 2008.

  17. Highly selective biomechanical separation of cancer cells from leukocytes using microfluidic ratchets and hydrodynamic concentrator.

    PubMed

    Lin, Bill K; McFaul, Sarah M; Jin, Chao; Black, Peter C; Ma, Hongshen

    2013-01-01

    The separation of cells based on their biomechanical properties, such as size and deformability, is important in applications such as the identification of circulating tumor cells, where morphological differences can be used to distinguish target cancer cells from contaminant leukocytes. Existing filtration-based separation processes are limited in their selectivity and their ability to extract the separated cells because of clogging in the filter microstructures. We present a cell separation device consisting of a hydrodynamic concentrator and a microfluidic ratchet mechanism operating in tandem. The hydrodynamic concentrator removes the majority of the fluid and a fraction of leukocytes based on size, while the microfluidic ratchet mechanism separates cancer cells from leukocytes based on a combination of size and deformability. The irreversible ratcheting process enables highly selective separation and robust extraction of separated cells. Using cancer cells spiked into leukocyte suspensions, the complete system demonstrated a yield of 97%, while enriching the concentration of target cancer cells 3000 fold relative to the concentration of leukocytes.

  18. Highly selective biomechanical separation of cancer cells from leukocytes using microfluidic ratchets and hydrodynamic concentrator

    PubMed Central

    Lin, Bill K.; McFaul, Sarah M.; Jin, Chao; Black, Peter C.; Ma, Hongshen

    2013-01-01

    The separation of cells based on their biomechanical properties, such as size and deformability, is important in applications such as the identification of circulating tumor cells, where morphological differences can be used to distinguish target cancer cells from contaminant leukocytes. Existing filtration-based separation processes are limited in their selectivity and their ability to extract the separated cells because of clogging in the filter microstructures. We present a cell separation device consisting of a hydrodynamic concentrator and a microfluidic ratchet mechanism operating in tandem. The hydrodynamic concentrator removes the majority of the fluid and a fraction of leukocytes based on size, while the microfluidic ratchet mechanism separates cancer cells from leukocytes based on a combination of size and deformability. The irreversible ratcheting process enables highly selective separation and robust extraction of separated cells. Using cancer cells spiked into leukocyte suspensions, the complete system demonstrated a yield of 97%, while enriching the concentration of target cancer cells 3000 fold relative to the concentration of leukocytes. PMID:24404034

  19. [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.

  20. The role of lysosomes in the selective concentration of mineral elements. A microanalytical study.

    PubMed

    Berry, J P

    1996-05-01

    The role of the lysosome during the intracellular concentration of diverse mineral elements has been evidenced by the electron probe X-ray microanalysis (EPMA). This highly sensitive technique allows an in situ chemical analysis of any chemical element with an atomic number greater than 11, present in ultra-thin tissue sections. Therefore, it has been demonstrated by using this EPMA that 21 out of the 92 elements of the periodic table, once injected in a soluble form, were selectively concentrated within lysosomes of several types of mammalian cells. Amongst these 21 elements, 15 are concentrated and precipitated in an insoluble from in association with phosphorus whereas the other 6 are precipitated in association with sulphur. Amongst the 15 elements which precipitate with phosphorus in lysosomes, there are: 3 group IIIB elements of the periodic system, (aluminium, gallium and indium); the rare-earth elements (cerium, gadolinium, lanthanum, thulium and samarium); 2 group IVA elements (hafnium and zirconium), two actinides (uranium and thorium) and elements such as chromium and niobium. The 6 elements which precipitate with sulphur comprise the 3 group VIII elements of the classification (nickel, palladium, platinum) and the 3 group IB elements (copper, silver and gold). The mechanisms responsible for this selective concentration involve enzymatic processes and predominantly acid phosphatases for elements precipitating as phosphates and arylsulfatases for elements precipitating with sulphur.

  1. Generation and characterization of stable, highly concentrated titanium dioxide nanoparticle aerosols for rodent inhalation studies

    NASA Astrophysics Data System (ADS)

    Kreyling, Wolfgang G.; Biswas, Pratim; Messing, Maria E.; Gibson, Neil; Geiser, Marianne; Wenk, Alexander; Sahu, Manoranjan; Deppert, Knut; Cydzik, Izabela; Wigge, Christoph; Schmid, Otmar; Semmler-Behnke, Manuela

    2011-02-01

    The intensive use of nano-sized titanium dioxide (TiO2) particles in many different applications necessitates studies on their risk assessment as there are still open questions on their safe handling and utilization. For reliable risk assessment, the interaction of TiO2 nanoparticles (NP) with biological systems ideally needs to be investigated using physico-chemically uniform and well-characterized NP. In this article, we describe the reproducible production of TiO2 NP aerosols using spark ignition technology. Because currently no data are available on inhaled NP in the 10-50 nm diameter range, the emphasis was to generate NP as small as 20 nm for inhalation studies in rodents. For anticipated in vivo dosimetry analyses, TiO2 NP were radiolabeled with 48V by proton irradiation of the titanium electrodes of the spark generator. The dissolution rate of the 48V label was about 1% within the first day. The highly concentrated, polydisperse TiO2 NP aerosol (3-6 × 106 cm-3) proved to be constant over several hours in terms of its count median mobility diameter, its geometric standard deviation, and number concentration. Extensive characterization of NP chemical composition, physical structure, morphology, and specific surface area was performed. The originally generated amorphous TiO2 NP were converted into crystalline anatase TiO2 NP by thermal annealing at 950 °C. Both crystalline and amorphous 20-nm TiO2 NP were chain agglomerated/aggregated, consisting of primary particles in the range of 5 nm. Disintegration of the deposited TiO2 NP in lung tissue was not detectable within 24 h.

  2. 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

  3. The effects of Mg enrichment of vegetable sprouts on Mg concentration, yield and ROS generation.

    PubMed

    Przybysz, Arkadiusz; Wrochna, Mariola; Małecka-Przybysz, Monika; Gawrońska, Helena; Gawroński, Stanisław W

    2016-08-01

    Two-thirds of the world's population do not consume the recommended amount of Mg, hence the demand for the production of Mg-enriched plants. Sprouts represent promising targets for enrichment. This study evaluated the effects of enriching broccoli, radish, alfalfa and mung bean sprouts with Mg (50-300 mg L(-1) ) on (i) the concentration of Mg and other ions, (ii) biomass accumulation, (iii) levels of reactive oxygen species (ROS), and (iv) the activity/content of enzymatic and non-enzymatic components of antioxidative systems. Enrichment of sprouts with Mg led to a significant increase in Mg concentration, especially in alfalfa (increase of 23-152 %), without depletion of other ions. A higher Mg concentration had a minor effect on biomass accumulation, but increased, often significantly, ROS generation and affected enzymatic and non-enzymatic antioxidative systems. The level of O2 (•-) increased most in broccoli, by 59-158%, while OH(•) increased most in radish, by 200-350%. Enrichment of sprouts with Mg is possible, but attention must be paid to elevated ROS levels in food. Mung bean sprouts are best suited to enrichment as they make a considerable contribution to the daily supplementation of Mg, at still low levels of ROS in enriched plants. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  4. Selective concentration of IgD class-specific antibodies in human milk.

    PubMed Central

    Litwin, S D; Zehr, B D; Insel, R A

    1990-01-01

    The participation of human IgD class antibody in local immune responses of breast tissue was studied by analysing the sera-to-milk ratios of total IgD, IgM, IgA, IgG isotypes and albumin found in matched samples, and by analysing the sera-to-milk (S/M) ratios of IgD, IgM, IgA, IgG antibodies against Haemophilus influenzae capsular polysaccharide (PRP), phosphorylcholine, tetanus and in some cases diphtheria antigens. The study group consisted of eight women immunized during pregnancy with PRP, and control, unimmunized women. Albumin, and total IgG showed high S/M ratios. IgA had a low S/M ratio as expected, consistent with reports that IgA is locally concentrated. Total IgD and IgM isotype ratio values were intermediate between IgG and IgA suggesting they were selectively concentrated in breast fluids due to local production or transport mechanisms, or both. Ratios for specific antibodies of IgA and IgM isotypes and for total IgA and IgM isotype showed parallel data. Among the IgD antibodies, those specific for PRP and phosphorylcholine suggested a higher degree of selective concentration as compared with tetanus antigen. In the group of unimmunized women, although selective concentration of total IgD was observed, specific antibody studies were inconclusive due to the low milk IgD antibody levels encountered. The results indicate that IgD (and also IgM) may participate in local immune responses of human breast tissues and fluids; possibly influenced by the nature of the antigen, the state of immunization and the hormonal environment (pregnancy). PMID:2357855

  5. 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

  6. 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.

  7. 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.

  8. Correction of target-controlled infusion following wrong selection of emulsion concentrations of propofol.

    PubMed

    Chae, Yun-Jeong; Joe, Han Bum; Lee, Won-Il; Kim, Jin-A; Min, Sang-Kee

    2014-05-01

    We investigated the correction methods following wrong-settings of emulsion concentrations of propofol as a countermeasure against erroneous target-controlled infusions (TCI). TCIs were started with targeting 4.0 µg/ml of effect-site concentration (Ceff) of propofol, and the emulsion concentrations were selected for 2.0% instead of 1.0% (FALSE1-2, n = 24), or 1.0% instead of 2.0% (FALSE2-1, n = 24). These wrong TCIs were corrected at 3 min after infusion start. During FALSE1-2, the deficit was filled up while injecting after equilibrium (n = 12), or while overriding (n = 12). During FALSE2-1, the overdose was evacuated while targeting Ceff (n = 12) or targeting plasma concentration (Cp) (n = 12). The gravimetrical measurements of TCI reproduced the Cp and Ceff using simulations. The reproduced Ceff at 3 min (Ceff-3min) and the time to be normalized within ± 5% of target Ceff (T±5%), were compared between the correction methods. During the wrong TCI, Ceff-3min was 1.98 ± 0.01 µg/ml in FALSE1-2, and 7.99 ± 0.05 µg/ml in FALSE2-1. In FALSE1-2, T±5% was significantly shorter when corrected while overriding (3.9 ± 0.25 min), than corrected after equilibrium (6.9 ± 0.05 min) (P < 0.001). In FALSE2-1, T±5% was significantly shorter during targeting Cp (3.6 ± 0.04 min) than targeting Ceff (6.7 ± 0.15 min) (P < 0.001). The correction methods, based on the pharmacokinetic and pharmacodynamic characteristics, could effectively and rapidly normalize the wrong TCI following erroneously selections of the emulsion concentration of propofol.

  9. Correction of target-controlled infusion following wrong selection of emulsion concentrations of propofol

    PubMed Central

    Chae, Yun-Jeong; Joe, Han Bum; Lee, Won-Il; Kim, Jin-A

    2014-01-01

    Background We investigated the correction methods following wrong-settings of emulsion concentrations of propofol as a countermeasure against erroneous target-controlled infusions (TCI). Methods TCIs were started with targeting 4.0 µg/ml of effect-site concentration (Ceff) of propofol, and the emulsion concentrations were selected for 2.0% instead of 1.0% (FALSE1-2, n = 24), or 1.0% instead of 2.0% (FALSE2-1, n = 24). These wrong TCIs were corrected at 3 min after infusion start. During FALSE1-2, the deficit was filled up while injecting after equilibrium (n = 12), or while overriding (n = 12). During FALSE2-1, the overdose was evacuated while targeting Ceff (n = 12) or targeting plasma concentration (Cp) (n = 12). The gravimetrical measurements of TCI reproduced the Cp and Ceff using simulations. The reproduced Ceff at 3 min (Ceff-3min) and the time to be normalized within ± 5% of target Ceff (T±5%), were compared between the correction methods. Results During the wrong TCI, Ceff-3min was 1.98 ± 0.01 µg/ml in FALSE1-2, and 7.99 ± 0.05 µg/ml in FALSE2-1. In FALSE1-2, T±5% was significantly shorter when corrected while overriding (3.9 ± 0.25 min), than corrected after equilibrium (6.9 ± 0.05 min) (P < 0.001). In FALSE2-1, T±5% was significantly shorter during targeting Cp (3.6 ± 0.04 min) than targeting Ceff (6.7 ± 0.15 min) (P < 0.001). Conclusions The correction methods, based on the pharmacokinetic and pharmacodynamic characteristics, could effectively and rapidly normalize the wrong TCI following erroneously selections of the emulsion concentration of propofol. PMID:24910730

  10. Measured carbon monoxide concentrations from stock and reduced-emission prototype portable generators operated in an attached garage.

    PubMed

    Emmerich, S J; Wang, L; Persily, A K

    2017-08-01

    There is concern about the hazard of acute residential CO exposures from portable gasoline-powered generators, which can result in death or serious adverse health effects in exposed individuals. To address this hazard, the U.S. Consumer Product Safety Commission has developed low CO emission prototype generators by adapting off-the-shelf emission control technologies onto commercially available generators. A series of tests was conducted to characterize the indoor CO concentrations resulting from portable generators operating in the attached garage of a research house under seven different test house/garage configurations. The tested generators include both unmodified and modified low CO emission prototypes. It was found that CO concentrations varied widely, with peak house CO concentrations ranging from under 10 ppm to over 10,000 ppm. The highest concentrations in the house resulted from operation of the unmodified generator in the garage with the garage bay door closed and the house access door open. The lowest concentrations resulted from operation of a modified low CO emission prototype in the garage with the garage bay door open and the house access door closed. These tests documented reductions of up to 98% in CO concentrations due to emissions from two low CO emission portable generators compared to a stock generator. Improper portable generator use has caused 800 U.S. deaths in the past 14 years. Generators operated in attached garages can cause CO to quickly reach deadly levels. Two low-emission prototypes generators were tested and had CO emissions reduced by up to 98%. Low-emission generators can reduce the risk of consumer poisonings and deaths.

  11. Using discrete choice modeling to generate resource selection functions for female polar bears in the Beaufort Sea

    USGS Publications Warehouse

    Durner, George M.; Amstrup, Steven C.; Nielson, Ryan M.; McDonald, Trent; Huzurbazar, Snehalata

    2004-01-01

    Polar bears (Ursus maritimus) depend on ice-covered seas to satisfy life history requirements. Modern threats to polar bears include oil spills in the marine environment and changes in ice composition resulting from climate change. Managers need practical models that explain the distribution of bears in order to assess the impacts of these threats. We explored the use of discrete choice models to describe habitat selection by female polar bears in the Beaufort Sea. Using stepwise procedures we generated resource selection models of habitat use. Sea ice characteristics and ocean depths at known polar bear locations were compared to the same features at randomly selected locations. Models generated for each of four seasons confirmed complexities of habitat use by polar bears and their response to numerous factors. Bears preferred shallow water areas where different ice types intersected. Variation among seasons was reflected mainly in differential selection of total ice concentration, ice stages, floe sizes, and their interactions. Distance to the nearest ice interface was a significant term in models for three seasons. Water depth was selected as a significant term in all seasons, possibly reflecting higher productivity in shallow water areas. Preliminary tests indicate seasonal models can predict polar bear distribution based on prior sea ice data.

  12. Proposal of Selection System of Shedding Generator at Fault Occurrence in Power System

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroshi; Yukita, Kazuto; Goto, Yasuyuki; Ichiyanagi, Katsuhiro; Tabata, Yasuhito; Ogawa, Shigeaki

    In recent years, complication of power system is progressing. Under such a situation, measures for high-speed stabilization are needed in order to prevent beforehand that the influence of the fault spreads for the whole system. If the fault occurs in power system, improvement of transient stability is expected by carrying out of generator shedding, i.e. some generators are separated temporarily. In this paper, the stability estimation system after generator shedding is constructed. Moreover, the neural network for selecting the suitable shedding generator taking account of stability after the fault was newly constructed.

  13. Selected Trace Element Concentrations in Peat Used for Cosmetic Production - A Case Study from Southern Poland

    NASA Astrophysics Data System (ADS)

    Glina, Bartłomiej

    2016-12-01

    The aim of the study was to assess the concentration of selected trace elements in organic soils used as a source to obtain a unique peat extract for cosmetics production. Peat material for laboratory analysis were collected from fen peatland located in the Prosna River Valley (Borek village). Studied peatland is managed by "Torf Corporation" company as a source of material to obtain peat extract for cosmetics production. In the collected soil samples (four soil profiles) Zn, Cu and Pb concentrations were determined by using atomic absorption spectrometer SpectraAA 220 (Varian), after acid digestion. Obtained results showed that the highest concentrations of selected trace elements were recorded in the surface horizons of organic soils. This fact might be the results of Prosna river flooding or air deposition. Howevere, according to the new Polish regulations (Ordinance of the Minister for Environment 01.09.2016 - the way of conducting contamination assessment of the earth surface), the content of trace elements in the examined soils was greatly belowe the permissible limit for areas from group IV (mine lands). Thus, described soils are proper to obtain peat extract used as a component in cosmetic production.

  14. 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

  15. Thymoproteasome subunit-β5T generates peptide-MHC complexes specialized for positive selection

    PubMed Central

    Xing, Yan; Jameson, Stephen C.; Hogquist, Kristin A.

    2013-01-01

    Cortical thymic epithelial cells (cTECs) express a unique thymoproteasome subunit-β5T that plays an essential role in the development of CD8 T cells. In contrast, the immunoproteasome subunit-β5i is expressed in other thymic antigen-presenting cells (APCs). The thymoproteasome may generate peptides that are specialized for positive selection, or it may simply serve to generate peptides that are distinct from other APCs that cause negative selection, thereby promoting an overall larger number of surviving clones to mature and function in the immune system. To distinguish these models, we genetically engineered mice to express distinct peptide repertoires in cTECs vs. other APCs without expressing β5T, by generating β5t5i knockin mice, in which β5i replaced β5T in cTECs. When such animals were crossed to β5i−/− mice, β5i was exclusively expressed in cTECs, whereas β5 was expressed in other cells. However, this mouse did not support normal positive selection, suggesting that β5T generates peptides that are intrinsically better for positive selection (i.e., β5i could not replace β5T) and not merely because these peptides are distinct from peptides presented by other APCs. Finally, using an Nur77GFP reporter, we show that the T cells generated in the absence of β5T have higher reactivity to self, generating predominantly CD44hi memory phenotype peripheral CD8+ T cells. Altogether, our results suggest that the thymoproteasome supports positive selection by generating peptides that are optimized for the selection of weakly self-reactive, naïve T-cell clones. PMID:23569244

  16. Microbial production host selection for converting second-generation feedstocks into bioproducts

    PubMed Central

    2009-01-01

    Background Increasingly lignocellulosic biomass hydrolysates are used as the feedstock for industrial fermentations. These biomass hydrolysates are complex mixtures of different fermentable sugars, but also inhibitors and salts that affect the performance of the microbial production host. The performance of six industrially relevant microorganisms, i.e. two bacteria (Escherichia coli and Corynebacterium glutamicum), two yeasts (Saccharomyces cerevisiae and Pichia stipitis) and two fungi (Aspergillus niger and Trichoderma reesei) were compared for their (i) ability to utilize monosaccharides present in lignocellulosic hydrolysates, (ii) resistance against inhibitors present in lignocellulosic hydrolysates, (iii) their ability to utilize and grow on different feedstock hydrolysates (corn stover, wheat straw, sugar cane bagasse and willow wood). The feedstock hydrolysates were generated in two manners: (i) thermal pretreatment under mild acid conditions followed by enzymatic hydrolysis and (ii) a non-enzymatic method in which the lignocellulosic biomass is pretreated and hydrolyzed by concentrated sulfuric acid. Moreover, the ability of the selected hosts to utilize waste glycerol from the biodiesel industry was evaluated. Results Large differences in the performance of the six tested microbial production hosts were observed. Carbon source versatility and inhibitor resistance were the major discriminators between the performances of these microorganisms. Surprisingly all 6 organisms performed relatively well on pretreated crude feedstocks. P. stipitis and A. niger were found to give the overall best performance C. glutamicum and S. cerevisiae were shown to be the least adapted to renewable feedstocks. Conclusion Based on the results obtained we conclude that a substrate oriented instead of the more commonly used product oriented approach towards the selection of a microbial production host will avoid the requirement for extensive metabolic engineering. Instead of

  17. On chip steady liquid-gas phase separation for flexible generation of dissolved gas concentration gradient.

    PubMed

    Xu, Bi-Yi; Hu, Shan-Wen; Yan, Xiao-Na; Xia, Xing-Hua; Xu, Jing-Juan; Chen, Hong-Yuan

    2012-04-07

    In this study, steady liquid-gas phase separation is realized by applying a hydrophobic small microchannel array (SMA) to bridge two large microchannels, one for liquid phase and one for gas phase. In this structure, a capillary pressure difference between that in the SMA and the larger channel results in a steady liquid-gas interface. The generated liquid-gas interface allows for fast gas dissolving speed. By coupling the liquid-gas interface with a one directional fluidic field, a steady dissolved gas concentration gradient (DgCG) is generated. The DgCG distribution is easily designable for linear or exponential modes, providing improved flexibility for gas participated processes on chip. To demonstrate its applicability, a CO(2) DgCG chip is fabricated and applied for screening CaCO(3) crystal growth conditions in the DgCG chip. Crystals with transitional structures are successfully fabricated, which is consistent with the CO(2) DgCG distribution. This journal is © The Royal Society of Chemistry 2012

  18. Modulation of photonic nanojets generated by microspheres decorated with concentric rings.

    PubMed

    Wu, M X; Huang, B J; Chen, R; Yang, Y; Wu, J F; Ji, R; Chen, X D; Hong, M H

    2015-07-27

    A novel design of decorating microsphere surface with concentric rings to modulate the photonic nanojet (PNJ) is investigated. By introducing the concentric ring structures into the illumination side of the microspheres, a reduction of the full width at half maximum (FWHM) intensity of the PNJ by 29.1%, compared to that without the decoration, can be achieved numerically. Key design parameters, such as ring number and depth, are analyzed. Engineered microsphere with four uniformly distributed rings etched at a depth of 1.2 μm and width of 0.25 μm can generate PNJ at a FWHM of 0.485 λ (λ = 400nm). Experiments were carried out by direct observation of the PNJ with an optical microscope under 405 nm laser illumination. As a result, shrinking of PNJ beam size of 28.0% compared to the case without the rings has been achieved experimentally. Sharp FWHM of this design can be beneficial to micro/nanoscale fabrication, optical super-resolution imaging, and sensing.

  19. 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

  20. Photovoltaic systems based on spectrally selective holographic concentrators. Final report, May-Dec 91

    SciTech Connect

    Ludman, J.E.

    1991-11-01

    The purpose of the work was to demonstrate the feasibility of a new holographic technique for concentrating solar energy and splitting its spectrum with a single hologram to generate power, using two or more solar cells optimized at different portion of the solar spectrum. Various holographic materials, techniques for making holograms, and combinations of solar cells of different materials were investigated. Techniques were developed for testing system efficiencies. A number of potential problems and difficulties were successfully addressed. Holograms and solar cell systems were fabricated and tested, and demonstration units fabricated.

  1. A rapid and robust selection procedure for generating drug-selectable marker-free recombinant malaria parasites

    PubMed Central

    Manzoni, Giulia; Briquet, Sylvie; Risco-Castillo, Veronica; Gaultier, Charlotte; Topçu, Selma; Ivănescu, Maria Larisa; Franetich, Jean-François; Hoareau-Coudert, Bénédicte; Mazier, Dominique; Silvie, Olivier

    2014-01-01

    Experimental genetics have been widely used to explore the biology of the malaria parasites. The rodent parasites Plasmodium berghei and less frequently P. yoelii are commonly utilised, as their complete life cycle can be reproduced in the laboratory and because they are genetically tractable via homologous recombination. However, due to the limited number of drug-selectable markers, multiple modifications of the parasite genome are difficult to achieve and require large numbers of mice. Here we describe a novel strategy that combines positive-negative drug selection and flow cytometry-assisted sorting of fluorescent parasites for the rapid generation of drug-selectable marker-free P. berghei and P. yoelii mutant parasites expressing a GFP or a GFP-luciferase cassette, using minimal numbers of mice. We further illustrate how this new strategy facilitates phenotypic analysis of genetically modified parasites by fluorescence and bioluminescence imaging of P. berghei mutants arrested during liver stage development. PMID:24755823

  2. A rapid and robust selection procedure for generating drug-selectable marker-free recombinant malaria parasites.

    PubMed

    Manzoni, Giulia; Briquet, Sylvie; Risco-Castillo, Veronica; Gaultier, Charlotte; Topçu, Selma; Ivănescu, Maria Larisa; Franetich, Jean-François; Hoareau-Coudert, Bénédicte; Mazier, Dominique; Silvie, Olivier

    2014-04-23

    Experimental genetics have been widely used to explore the biology of the malaria parasites. The rodent parasites Plasmodium berghei and less frequently P. yoelii are commonly utilised, as their complete life cycle can be reproduced in the laboratory and because they are genetically tractable via homologous recombination. However, due to the limited number of drug-selectable markers, multiple modifications of the parasite genome are difficult to achieve and require large numbers of mice. Here we describe a novel strategy that combines positive-negative drug selection and flow cytometry-assisted sorting of fluorescent parasites for the rapid generation of drug-selectable marker-free P. berghei and P. yoelii mutant parasites expressing a GFP or a GFP-luciferase cassette, using minimal numbers of mice. We further illustrate how this new strategy facilitates phenotypic analysis of genetically modified parasites by fluorescence and bioluminescence imaging of P. berghei mutants arrested during liver stage development.

  3. Generation of Platelet Microparticles after Cryopreservation of Apheresis Platelet Concentrates Contributes to Hemostatic Activity.

    PubMed

    Eker, İbrahim; Yılmaz, Soner; Çetinkaya, Rıza Aytaç; Pekel, Aysel; Ünlü, Aytekin; Gürsel, Orhan; Yılmaz, Sebahattin; Avcu, Ferit; Muşabak, Uğur; Pekoğlu, Ahmet; Ertaş, Zerrin; Açıkel, Cengizhan; Zeybek, Nazif; Kürekçi, Ahmet Emin; Avcı, İsmail Yaşar

    2017-03-01

    In the last decade, substantial evidence has accumulated about the use of cryopreserved platelet concentrates, especially in trauma. However, little reference has been made in these studies to the morphological and functional changes of platelets. Recently platelets have been shown to be activated by cryopreservation processes and to undergo procoagulant membrane changes resulting in the generation of platelet-derived microparticles (PMPs), platelet degranulation, and release of platelet-derived growth factors (PDGFs). We assessed the viabilities and the PMP and PDGF levels of cryopreserved platelets, and their relation with thrombin generation. Apheresis platelet concentrates (APCs) from 20 donors were stored for 1 day and cryopreserved with 6% dimethyl sulfoxide. Cryopreserved APCs were kept at -80 °C for 1 day. Thawed APCs (100 mL) were diluted with 20 mL of autologous plasma and specimens were analyzed for viabilities and PMPs by flow cytometry, for thrombin generation by calibrated automated thrombogram, and for PDGFs by enzyme-linked immunosorbent assay testing. The mean PMP and PDGF levels in freeze-thawed APCs were significantly higher (2763±399.4/µL vs. 319.9±80.5/µL, p<0.001 and 550.9±73.6 pg/mL vs. 96.5±49 pg/mL, p<0.001, respectively), but the viability rates were significantly lower (68.2±13.7% vs. 94±7.5%, p<.001) than those of fresh APCs. The mean endogenous thrombin potential (ETP) of freeze-thawed APCs was significantly higher than that of the fresh APCs (3406.1±430.4 nM.min vs. 2757.6±485.7 nM.min, p<0.001). Moreover, there was a significant positive poor correlation between ETP levels and PMP levels (r=0.192, p=0.014). Our results showed that, after cryopreservation, while levels of PMPs were increasing, significantly higher and earlier thrombin formation was occurring in the samples analyzed despite the significant decrease in viability. Considering the damage caused by the freezing process and the scarcity of evidence for their in

  4. Increased ubiquinone concentration after intracerebroventricularly-administered ubiquinol to selected rat brain regions.

    PubMed

    Gvozdjáková, Anna; Mravec, Boris; Kucharská, Jarmila; Lackovičová, Lubica; Ondičová, Katarína; Tkačov, Martin; Singh, Ram B

    2012-12-01

    Brain coenzyme Q10 (CoQ10) concentration can influence the activity of several brain regions, including those which participate in the regulation of cardiovascular circadian rhythms, food intake, neuroendocrine stress response, activity and sleep regulation. However, the effect of supplemented ubiquinol (reduced CoQ) into brain regions is not known. This study determined baseline levels of ubiquinone (oxidized CoQ) in various rat brain regions and proved the bioavailability of the liposomal ubiquinol to selected brain regions after its administration into right brain ventricle. Our data indicate that administration of ubiquinol may create the basis for modulation of neuronal activities in specific brain regions.

  5. Concentration Polarisation in the Electrodialysis Process and the Polarisation Characteristics of Ion-selective Membranes

    NASA Astrophysics Data System (ADS)

    Balavadze, Elyusbar M.; Bobreshova, O. V.; Kulintsov, P. I.

    1988-06-01

    Complications in the electrodialysis process, due to the occurrence of concentration polarisation, are analysed. It is shown that most present-day methods for measuring the electrochemical characteristics of ion-selective membranes are not suitable for monitoring the behaviour of these membranes over a wide range of polarising current densities. An analysis of the polarisation characteristics of electromembrane systems shows the advantages of a system with a rotating membrane disc. It is shown that in the polarisation process there is a significant deterioration of the electrochemical properties of heterogeneous membranes whereas the properties of homogeneous perfluorinated sulpho-cation-exchange membranes remain almost unchanged. The bibliography includes 43 references.

  6. Geographic consistency and variation in conflicting selection generated by pollinators and seed predators.

    PubMed

    Sun, Shi-Guo; Armbruster, W Scott; Huang, Shuang-Quan

    2016-08-01

    Floral traits that attract pollinators may also attract seed predators, which, in turn, may generate conflicting natural selection on such traits. Although such selection trade-offs are expected to vary geographically, few studies have investigated selection mediated by pollinators and seed predators across a geographic mosaic of environments and floral variation. Floral traits were investigated in 14 populations of the bumble-bee-pollinated herb, Pedicularis rex, in which tubular flowers are subtended by cupular bracts holding rain water. To study potentially conflicting selection on floral traits generated by pollinators and florivores, stigmatic pollen loads, initial seed set, pre-dispersal seed predation and final viable seed production were measured in 12-14 populations in the field. Generalized Linear Model (GLM) analyses indicated that the pollen load on stigmas was positively related to the exsertion of the corolla beyond the cupular bracts and size of the lower corolla lip, but so too was the rate of seed predation, creating conflicting selection on both floral traits. A geographic mosaic of selection mediated by seed predators, but not pollinators, was indicated by significant variation in levels of seed predation and the inclusion of two-, three- and four-way interaction terms between population and seed predation in the best model [lowest corrected Akaike Information Criterion (AICc)] explaining final seed production. These results indicate opposing selection in operation: pollinators generated selection for greater floral exsertion beyond the bracts, but seed predators generated selection for reduced exsertion above the protective pools of water, although the strength of the latter varied across populations. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Geographic consistency and variation in conflicting selection generated by pollinators and seed predators

    PubMed Central

    Sun, Shi-Guo; Armbruster, W. Scott; Huang, Shuang-Quan

    2016-01-01

    Backgrounds and Aims Floral traits that attract pollinators may also attract seed predators, which, in turn, may generate conflicting natural selection on such traits. Although such selection trade-offs are expected to vary geographically, few studies have investigated selection mediated by pollinators and seed predators across a geographic mosaic of environments and floral variation. Methods Floral traits were investigated in 14 populations of the bumble-bee-pollinated herb, Pedicularis rex, in which tubular flowers are subtended by cupular bracts holding rain water. To study potentially conflicting selection on floral traits generated by pollinators and florivores, stigmatic pollen loads, initial seed set, pre-dispersal seed predation and final viable seed production were measured in 12–14 populations in the field. Key Results Generalized Linear Model (GLM) analyses indicated that the pollen load on stigmas was positively related to the exsertion of the corolla beyond the cupular bracts and size of the lower corolla lip, but so too was the rate of seed predation, creating conflicting selection on both floral traits. A geographic mosaic of selection mediated by seed predators, but not pollinators, was indicated by significant variation in levels of seed predation and the inclusion of two-, three- and four-way interaction terms between population and seed predation in the best model [lowest corrected Akaike Information Criterion (AICc)] explaining final seed production. Conclusions These results indicate opposing selection in operation: pollinators generated selection for greater floral exsertion beyond the bracts, but seed predators generated selection for reduced exsertion above the protective pools of water, although the strength of the latter varied across populations. PMID:27325896

  8. 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.

  9. Measurement of breath acetone concentrations by selected ion flow tube mass spectrometry in type 2 diabetes.

    PubMed

    Storer, Malina; Dummer, Jack; Lunt, Helen; Scotter, Jenny; McCartin, Fiona; Cook, Julie; Swanney, Maureen; Kendall, Deborah; Logan, Florence; Epton, Michael

    2011-12-01

    Selected ion flow tube-mass spectrometry (SIFT-MS) can measure volatile compounds in breath on-line in real time and has the potential to provide accurate breath tests for a number of inflammatory, infectious and metabolic diseases, including diabetes. Breath concentrations of acetone in type 2 diabetic subjects undertaking a long-term dietary modification programme were studied. Acetone concentrations in the breath of 38 subjects with type 2 diabetes were determined by SIFT-MS. Anthropomorphic measurements, dietary intake and medication use were recorded. Blood was analysed for beta hydroxybutyrate (a ketone body), HbA1c (glycated haemoglobin) and glucose using point-of-care capillary (fingerprick) testing. All subjects were able to undertake breath manoeuvres suitable for analysis. Breath acetone varied between 160 and 862 ppb (median 337 ppb) and was significantly higher in men (median 480 ppb versus 296 ppb, p = 0.01). In this cross-sectional study, no association was observed between breath acetone and either dietary macronutrients or point-of-care capillary blood tests. Breath analysis by SIFT-MS offers a rapid, reproducible and easily performed measurement of acetone concentration in ambulatory patients with type 2 diabetes. The high inter-individual variability in breath acetone concentration may limit its usefulness in cross-sectional studies. Breath acetone may nevertheless be useful for monitoring metabolic changes in longitudinal metabolic studies, in a variety of clinical and research settings.

  10. 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

  11. Increasing Glucose Concentrations Interfere with Estimation of Electrolytes by Indirect Ion Selective Electrode Method.

    PubMed

    Goyal, Bela; Datta, Sudip Kumar; Mir, Altaf A; Ikkurthi, Saidaiah; Prasad, Rajendra; Pal, Arnab

    2016-04-01

    The estimation of electrolytes like sodium (Na(+)), potassium (K(+)) and chloride (Cl(-)) using direct and indirect ion-selective electrodes (ISE) is a routine laboratory practice. Interferents like proteins, triglycerides, drugs etc. are known to affect the results. The present study was designed to look into the effect of increasing glucose concentrations on estimation of Na(+), K(+) and Cl(-) by direct and indirect ISE. Pooled sera was mixed with glucose stock solution (20 g/dL) prepared in normal saline to obtain glucose concentrations ranging from ~100 to ~5000 mg/dL. Na(+), K(+) and Cl(-) levels were estimated by direct and indirect ISE analyzers and results were statistically analysed using ANOVA and Pearson's correlation. Similar experiment was also performed in 24 h urine sample from healthy subjects. Significant difference was observed between Na(+) and Cl(-) measurements by direct and indirect ISE, with indirect ISE values being consistently higher than direct ISE. Besides this, significant difference was observed amongst Na(+) and Cl(-) values from baseline values obtained by indirect ISE at glucose concentrations ≥2486 mg/dL. However, no such difference was observed with direct ISE. Na(+) and Cl(-) estimation by indirect ISE showed significant negative correlation with glucose concentration, more so, above ~2000 mg/dL. K(+), however, showed no significant difference with varying glucose. Similar results were observed in 24 h urine samples with a significant difference observed amongst Na(+) and Cl(-) values at ≥2104 mg/dL glucose. Thus we conclude that high glucose concentrations interfere significantly in estimation of Na(+) and Cl(-) by indirect ISE in serum as well as urine.

  12. 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. © 2014 International Union of Psychological Science.

  13. 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...

  14. 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...

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

    PubMed

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

    2016-07-12

    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.

  16. 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

  17. Relationships between mercury concentration and food selectivity of many kinds of fishes in Minamata Bay

    NASA Astrophysics Data System (ADS)

    Mori, K.; Kanaya, G.

    2016-02-01

    Serious injuries occurred in residents who consumed fish and shellfishes in Minamata Bay polluted by high-concentration methyl-mercury in the 1950s. Pollution has fallen to a safe level because of the pollution prevention project (dredging etc.) carried out from 1977 to 1990. From 2010 we have been researching the bioaccumulation of mercury in several fishes in Minamata Bay and surrounding areas. We selected several sampling points that showed different environmental conditions, species composition and food web patterns. For the determination of feeding types of 60 species fishes (600 samples) sampled by gill net, we measured mercury levels of each sample and directly checked food items in gut, and distinguished carnivore, omnivore, herbivore and detritivore. At this time, we introduced a stable isotope analysis for checking the food history and feeding habits of dominant fish. In about 300 individuals of 30 species of dominant fish selected from the 600 samples, we measured the stable nitrogen and carbon isotope ratios (δ15N, δ13C) of each sample. Checking the food items in gut of fishes, more than 80% of fishes were carnivorous, and showed different selectivity of food items, such as fish, crustacean and so on. From the results of stable isotope ratios, benthic fish tended to show a higher ratio of δ13C. Usually benthic microalgae evidenced a higher ratio of δ13C than planktonic microalgae, and the ratio conservative through the food chain. In general, δ15N increases through the food chain with +3 to +4 ‰ enrichment per trophic step. In these data, carnivorous fishes of benthic and pelagic type showed medium and high ratios of δ15N. From comparing the stable isotope ratio to the mercury concentration of fishes, all of the high-mercury fishes belonged to benthic and carnivorous types. We consider the joint method of food web analysis and stable isotope analysis to be useful for understanding the mechanism of mercury bioaccumulation through the food web

  18. 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.

  19. Mutant prevention concentration and mutant selection window for 10 antimicrobial agents against Rhodococcus equi.

    PubMed

    Berghaus, Londa J; Giguère, Steeve; Guldbech, Kristen

    2013-10-25

    The objectives of this study were to determine the mutant prevention concentration (MPC), time above the MPC and mutant selection window for 10 antimicrobial agents against Rhodococcus equi and to determine if the combination of a macrolide with rifampin would decrease emergence of resistant mutants. Antimicrobial agents investigated (erythromycin, clarithromycin, azithromycin, rifampin, amikacin, gentamicin, enrofloxacin, vancomycin, imipenem, and doxycycline) were selected based on in vitro activity and frequency of use in foals or people infected with R. equi. Each antimicrobial agent or combination of agents was evaluated against four virulent strains of R. equi. MPC were determined using an agar plate assay. Pharmacodynamic parameters were calculated using published plasma and pulmonary pharmacokinetic variables. There was a significant (P<0.001) effect of the type of antimicrobial agent on the MPC. The MPC of clarithromycin (1.0 μg/ml) was significantly lower and the MPC of rifampin and amikacin (512 and 384 μg/ml, respectively) were significantly higher than that of all other antimicrobial agents tested. Combining erythromycin, clarithromycin, or azithromycin with rifampin resulted in a significant (P≤0.005) decrease in MPC and MPC/MIC ratio. When MIC and MPC were combined with pharmacokinetic variables, only gentamicin and vancomycin were predicted to achieve plasma concentrations above the MPC for any given periods of time. Only clarithromycin and the combination clarithromycin-rifampin were predicted to achieve concentrations in bronchoalveolar cells and pulmonary epithelial lining fluid above the MPC for the entire dosing interval. In conclusion, the combination of a macrolide with rifampin considerably decreases the emergence of resistant mutants of R. equi. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Urinary metabolite concentrations of organophosphorous pesticides, bisphenol A, and phthalates among pregnant women in Rotterdam, the Netherlands: The Generation R Study

    PubMed Central

    Ye, Xibiao; Pierik, Frank H.; Hauser, Russ; Duty, Susan; Angerer, Jürgen; Park, Melissa M.; Burdorf, Alex; Hofman, Albert; Jaddoe, Vincent W.V.; Mackenbach, Johan P.; Steegers, Eric A.P.; Tiemeier, Henning; Longnecker, Matthew P.

    2008-01-01

    Concern about potential health impacts of low level exposures to organophosphorus (OP) pesticides, bisphenol A (BPA), and phthalates among the general population is increasing. We measured levels of six dialkyl phosphate (DAP) metabolites of OP pesticides, a chlorpyrifos-specific metabolite (3,5,6-trichloro-2-pyridinol, TCPy), BPA, and fourteen phthalate metabolites in urine samples of 100 pregnant women from the Generation R study, the Netherlands. The unadjusted and creatinine-adjusted concentrations were reported, and compared to National Health and Nutrition Examination Survey and other studies. In general, these metabolites were detectable in the urine of the women from the Generation R study and compared with other groups, they had relatively high level exposures to OP pesticides and several phthalates but similar exposure to BPA. The median concentrations of total dimethyl (DM) metabolites was 264.0 nmol/g creatinine (Cr) and of total DAP was 316.0 nmol/g Cr. The median concentration of mono-ethyl phthalate (MEP) was 222.0 µg/g Cr; the median concentrations of mono-isobutyl phthalate (MiBP) and mono-n-butyl phthalate (MnBP) were above 50 µg/g Cr. The median concentrations of the three secondary metabolites of di-2-ethylhexyl phthalate (DEHP) were greater than 20 µg/g Cr. The data indicate that the Generation R study population provides a wide distribution of selected environmental exposures. Reasons for the relatively high levels and possible health effects need investigation. PMID:18774129

  6. Blood Selenium Concentration and Blood Cystatin C Concentration in a Randomly Selected Population of Healthy Children Environmentally Exposed to Lead and Cadmium.

    PubMed

    Gać, Paweł; Pawlas, Natalia; Wylężek, Paweł; Poręba, Rafał; Poręba, Małgorzata; Pawlas, Krystyna

    2017-01-01

    This study aimed at evaluation of a relationship between blood selenium concentration (Se-B) and blood cystatin C concentration (CST) in a randomly selected population of healthy children, environmentally exposed to lead and cadmium. The studies were conducted on 172 randomly selected children (7.98 ± 0.97 years). Among participants, the subgroups were distinguished, manifesting marginally low blood selenium concentration (Se-B 40-59 μg/l), suboptimal blood selenium concentration (Se-B: 60-79 μg/l) or optimal blood selenium concentration (Se-B ≥ 80 μg/l). At the subsequent stage, analogous subgroups of participants were selected separately in groups of children with BMI below median value (BMI <16.48 kg/m(2)) and in children with BMI ≥ median value (BMI ≥16.48 kg/m(2)). In all participants, values of Se-B and CST were estimated. In the entire group of examined children no significant differences in mean CST values were detected between groups distinguished on the base of normative Se-B values. Among children with BMI below 16.48 kg/m(2), children with marginally low Se-B manifested significantly higher mean CST values, as compared to children with optimum Se-B (0.95 ± 0.07 vs. 0.82 ± 0.15 mg/l, p < 0.05). In summary, in a randomly selected population of healthy children no relationships could be detected between blood selenium concentration and blood cystatin C concentration. On the other hand, in children with low body mass index, a negative non-linear relationship was present between blood selenium concentration and blood cystatin C concentration.

  7. Response to selection for fast growth in the second generation of Pacific oyster ( Crassostrea gigas)

    NASA Astrophysics Data System (ADS)

    Wang, Qingzhi; Li, Qi; Kong, Lingfeng; Yu, Ruihai

    2012-09-01

    Mass selection for fast growth was conducted in three Pacific oyster ( Crassostrea gigas) stocks from China, Japan and Korea using previously established lines (CS1, JS1, and KS1). To determine whether continuous progress can be achieved by selection for growth, the progeny of three second-generation Pacific oyster lines was selected for shell height and evaluated via a 400-day farming experiment. When harvested at the end of the experiment, the selected crosses of CS2, JS2, and KS2 lines grew by 9.2%, 10.2% and 9.6% larger than the control crosses, respectively. During grow-out stage, the genetic gain of three selected lines was (10.2 ± 1.4)%, (10.4 ± 0.3)%, and (8.4 ± 1.6)%, respectively; and the corresponding realized heritability was 0.457 ± 0.143, 0.312 ± 0.071 and 0.332 ± 0.009, respectively. These results indicated that the selection for fast growth achieved steady progress in the second generation of oyster. Our work provides supportive evidence for the continuity of the Pacific oyster selective breeding program.

  8. Enhanced power generation in concentrated photovoltaics using broadband antireflective coverglasses with moth eye structures.

    PubMed

    Song, Young Min; Jeong, Yonkil; Yeo, Chan Il; Lee, Yong Tak

    2012-11-05

    We present the effect of broadband antireflective coverglasses (BARCs) with moth eye structures on the power generation capability of a sub-receiver module for concentrated photovoltaics. The period and height of the moth eye structures were designed by a rigorous coupled-wave analysis method in order to cover the full solar spectral ranges without transmission band shrinkage. The BARCs with moth eye structures were prepared by the dry etching of silver (Ag) nanomasks, and the fabricated moth eye structures on coverglass showed strongly enhanced transmittance compared to the bare glass with a flat surface, at wavelengths of 300 - 1800 nm. The BARCs were mounted on InGaP/GaAs/Ge triple-junction solar cells and the power conversion efficiency of this sub-receiver module reached 42.16% for 196 suns, which is a 7.41% boosted value compared to that of a module with bare coverglass, without any detrimental changes of the open circuit voltages (V(oc)) and fill factor (FF).

  9. 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.

  10. Retrofitting genetic-economic indexes to demonstrate responses to selection across 2 generations of Holsteins

    USDA-ARS?s Scientific Manuscript database

    Three U.S. genetic-economic indexes for dairy cattle were retrofitted to demonstrate the progress that would have been made for currently evaluated traits if selection had been based on those indexes across 2 generations. Holstein bulls were categorized by quintile for each index, and 25 cow groups ...

  11. The generation of criteria for selecting analytical tools for landscape management

    Treesearch

    Marilyn Duffey-Armstrong

    1979-01-01

    This paper presents an approach to generating criteria for selecting the analytical tools used to assess visual resources for various landscape management tasks. The approach begins by first establishing the overall parameters for the visual assessment task, and follows by defining the primary requirements of the various sets of analytical tools to be used. Finally,...

  12. Genetic Variance in the F2 Generation of Divergently Selected Parents

    Treesearch

    M.P. Koshy; G. Namkoong; J.H. Roberds

    1998-01-01

    Either by selective breeding for population divergence or by using natural population differences, F2 and advanced generation hybrids can be developed with high variances. We relate the size of the genetic variance to the population divergence based on a forward and backward mutation model at a locus with two alleles with additive gene action....

  13. THREE-PEE SAMPLING THEORY and program 'THRP' for computer generation of selection criteria

    Treesearch

    L. R. Grosenbaugh

    1965-01-01

    Theory necessary for sampling with probability proportional to prediction ('three-pee,' or '3P,' sampling) is first developed and then exemplified by numerical comparisons of several estimators. Program 'T RP' for computer generation of appropriate 3P-sample-selection criteria is described, and convenient random integer dispensers are...

  14. 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.

  15. 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

  16. 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

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

    2013-05-01

    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.

  17. 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.

  18. Forward vs. backwards selection for seed orchards and cooperative second-generation breeding in the US Pacific Northwest.

    Treesearch

    R. Johnson; K. Jayawickrama

    2003-01-01

    Gain from various orchard strategies were modeled. The scenario tested 2,000 first-generation open-pollinated families, from which orchards of 20 selections were formed, using either parents, progeny or both. This was followed by a second-generation breeding population in which 200 full-sib families were tested followed by a second-generation orchard of 20 selections....

  19. 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.

  20. 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.

  1. 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 μg/L (micrograms per liter) and 0.853 μg/L, respectively. Other pharmaceuticals and their respective maximum concentrations were carbamazepine (0.516 μg/L) and ibuprofen (0.277 μg/L). For streams receiving wastewater effluents, the antibiotic azithromycin had the greatest concentration (1.65 μg/L), followed by sulfamethoxazole (1.34 μg/L), ofloxacin (0.329

  2. 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

  3. 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

  4. [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).

  5. 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.

  6. Increased efficiency of luminescent solar concentrators after application of organic wavelength selective mirrors.

    PubMed

    Verbunt, Paul P C; Tsoi, Shufen; Debije, Michael G; Broer, Dirk J; Bastiaansen, Cees W M; Lin, Chi-Wen; de Boer, Dick K G

    2012-09-10

    Organic wavelength-selective mirrors are used to reduce the loss of emitted photons through the surface of a luminescent solar concentrator (LSC). A theoretical calculation suggests that application of a 400 nm broad reflector on top of an LSC containing BASF Lumogen Red 305 as a luminophore can reflect 91% of all surface emitted photons back into the device. Used in this way, such broad reflectors could increase the edge-emission efficiency of the LSC by up to 66%. Similarly, 175 nm broad reflectors could increase efficiency up to 45%. Measurements demonstrate more limited effectiveness and dependency on the peak absorbance of the LSC. At higher absorbance, the increased number of internal re-absorption events reduces the effectiveness of the reflectors, leading to a maximum increase in LSC efficiency of ~5% for an LSC with a peak absorbance of 1. Reducing re-absorption by reducing dye concentration or the coverage of the luminophore coating results in an increase in LSC efficiency of up to 30% and 27%, respectively.

  7. Relationship between brain serotonin transporter binding, plasma concentration and behavioural effect of selective serotonin reuptake inhibitors.

    PubMed

    Hirano, Kazufumi; Kimura, Ryohei; Sugimoto, Yumi; Yamada, Jun; Uchida, Shinya; Kato, Yasuhiro; Hashimoto, Hisakuni; Yamada, Shizuo

    2005-03-01

    1. The present study was undertaken to characterise the relationship between in vivo brain serotonin transporter (SERT) binding, plasma concentration and pharmacological effect of selective serotonin reuptake inhibitors (SSRIs) in mice. Oral administration of fluvoxamine, fluoxetine, paroxetine and sertraline at pharmacologically relevant doses exerted dose- and time-dependent binding activity of brain SERT as revealed by significant increases in KD for specific [3H]paroxetine binding, and the in vivo SERT-binding potency was in the order of paroxetine>fluoxetine, sertraline>fluvoxamine. 2. The time courses of brain SERT binding by SSRIs in mice were mostly in parallel to those of their plasma concentrations. Also, norfluoxetine (active metabolite) has been suggested to contribute largely to the long-lasting binding activity of brain SERT after the fluoxetine administration. 3. Oral administration of each SSRI suppressed significantly the marble-burying behaviour with no change in locomotor activity in mice, and the extent and time course of suppression agreed well with those of brain SERT binding. Thus, the pharmacological potencies of SSRIs in the attenuation of marble-burying behaviour correlated significantly with their brain SERT binding activities. 4. In conclusion, the present study has provided the first in vivo evidences to support that fluvoxamine, fluoxetine, paroxetine and sertraline orally administered bind to the pharmacologically relevant brain SERT in mice and that their SERT-binding characteristics is closely associated with the pharmacokinetics and inhibition of marble-burying behaviour.

  8. 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

  9. Non-tinted Transparent Luminescent Solar Concentrators Employing Both UV and NIR Selective Absorbers

    NASA Astrophysics Data System (ADS)

    Zhao, Yimu; Lunt, Richard

    2014-03-01

    Luminescent solar concentrators are a potentially low-cost solar harvesting solution that additionally offer opportunities for integration around buildings and windows. However, the visible absorption and emission of previously demonstrated chromophores hamper their widespread applications including solar windows. Here, we demonstrate non-tinted transparent luminescent solar concentrators (TLSC) that employ both ultraviolet (UV) and near-infrared (NIR) selective absorbing luminophores that create an entirely new paradigm for power-producing transparent surfaces and enhances the potential over UV-only TLSCs. We have previously designed UV-harvesting systems composed of metal halide phosphorescent luminophore blends that enable absorption cutoff positioned at the edge of visible spectrum (430nm) and massive-downconverted emission in the near-infrared (800nm) with quantum yields for luminescence of 75%. Here, we have developed a complimentary TLSC employing fluorescent organic salts with both efficient NIR absorption and deeper NIR emission. We will discuss the photophysical properties of these luminophores, the impact of ligand-host control, and optimization of the TLSC architectures.

  10. Concentration levels of new-generation fungicides in throughfall released by foliar wash-off from vineyards.

    PubMed

    Pérez-Rodríguez, P; Soto-Gómez, D; Paradelo, M; López-Periago, J E

    2017-12-01

    The presence of agricultural pesticides in the environment and their effects on ecosystems are major concerns addressed in a significant number of articles. However, limited information is available on the pesticide concentrations released from crops. This study reports losses of new-generation fungicides by foliar wash-off from vineyards and their potential impact on the concentrations of their main active substances (AS) in surface waters. Two experimental plots devoted to vineyards were treated with various combinations of commercial new-generation fungicide formulations. Then, up to sixteen throughfall collectors were installed under the canopy. Concentrations of sixteen different AS in throughfall were determined along nine rainfall episodes. Concentrations in throughfall far exceeded the maximum permissible levels for drinking water established by the European Union regulations. Dynamics of fungicide release indicated a first-flush effect in the wash-off founding the highest concentrations of AS in the first rain episodes after application of the fungicides. This article shows that foliar spray application of commercial formulations of new-generation fungicides does not prevent the release of their AS to soil or the runoff. Concentration data obtained in this research can be valuable in supporting the assessment of environmental effects of new-generation fungicides and modeling their environmental fate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Quantitative trait loci affecting response to crowding stress in an F(2) generation of rainbow trout produced through phenotypic selection.

    PubMed

    Rexroad, Caird E; Vallejo, Roger L; Liu, Sixin; Palti, Yniv; Weber, Gregory M

    2013-10-01

    Selective breeding programs for salmonids typically aim to improve traits associated with growth and disease resistance. It has been established that stressors common to production environments can adversely affect these and other traits which are important to producers and consumers. Previously, we employed phenotypic selection to create families that exhibit high or low plasma cortisol concentrations in response to crowding stress. Subsequent crosses of high × low phenotypes founded a multigenerational breeding scheme with the aim of dissecting the genetic basis for variation underlying stress response through the identification of quantitative trait loci (QTL). Multiple methods of QTL analyses differing in their assumptions of homozygosity of the causal alleles in the grandparental generation yielded similar results in the F1 generation, and the analysis of two stress response phenotype measurement indexes were highly correlated. In the current study, we conducted a genome scan with microsatellites to detect QTL in the F2 generation of two families created through phenotypic selection and having larger numbers of offspring than families screened in the previous generation. Seven suggestive and three significant QTL were detected, seven of which were not previously detected in the National Center for Cool and Cold Water Aquaculture germplasm, bringing the total number of chromosomes containing significant and suggestive stress response QTL to 4 and 15, respectively. One significant QTL which peaks at 7 cM on chromosome Omy12 spans 12 cM and explains 25 % of the phenotypic variance in family 2008052 particularly warrants further investigation. Five QTL with significant parent-of-origin effects were detected in family 2008052, including two QTL on Omy12. The 95 % confidence intervals for the remaining QTL we detected were broad, requiring validation and fine mapping with other genotyping approaches and mapping strategies. These results will facilitate

  12. 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.

  13. 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.

  14. Human Th2 cells selectively express the orexigenic peptide, pro-melanin-concentrating hormone

    PubMed Central

    Sandig, Hilary; McDonald, Joanne; Gilmour, Jane; Arno, Matthew; Lee, Tak H.; Cousins, David J.

    2007-01-01

    Th1 and Th2 cells represent the two main functional subsets of CD4+ T helper cell, and are defined by their cytokine expression. Human Th1 cells express IFNγ, whilst Th2 cells express IL-4, IL-5, and IL-13. Th1 and Th2 cells have distinct immunological functions, and can drive different immunopathologies. Here, we show that in vitro-differentiated human Th2 cells highly selectively express the gene for pro-melanin-concentrating hormone (PMCH), using real-time RT-PCR, enzyme immunoassay, and Western blot analysis. PMCH encodes the prohormone, promelanin-concentrating hormone (PMCH), which is proteolytically processed to produce several peptides, including the orexigenic hormone melanin-concentrating hormone (MCH). PMCH expression by Th2 cells was activation responsive and increased throughout the 28-day differentiation in parallel with the expression of the Th2 cytokine genes. MCH immunoreactivity was detected in the differentiated Th2 but not Th1 cell culture supernatants after activation, and contained the entire PMCH protein, in addition to several smaller peptides. Human Th1 and Th2 cells were isolated by their expression of IFNγ and CRTH2, respectively, and the ex vivo Th2 cells expressed PMCH upon activation, in contrast to the Th1 cells. Because Th2 cells are central to the pathogenesis of allergic diseases including asthma, expression of PMCH by activated Th2 cells in vivo may directly link allergic inflammation to energy homeostasis and may contribute to the association between asthma and obesity. PMID:17640905

  15. Endogenous concentrations, pharmacokinetics, and selected pharmacodynamic effects of a single dose of exogenous GABA in horses.

    PubMed

    Knych, H K; Steinmetz, S J; McKemie, D S

    2015-04-01

    The anti-anxiety and calming effects following activation of the GABA receptor have been exploited in performance horses by administering products containing GABA. The primary goal of the study reported here was to describe endogenous concentrations of GABA in horses and the pharmacokinetics, selected pharmacodynamic effects, and CSF concentrations following administration of a GABA-containing product. The mean (±SD) endogenous GABA level was 36.4 ± 12.5 ng/mL (n = 147). Sixteen of these horses received a single intravenous and oral dose of GABA (1650 mg). Blood, urine, and cerebrospinal fluid (n = 2) samples were collected at time 0 and at various times for up to 48 h and analyzed using LC-MS. Plasma clearance and volume of distribution was 155.6 and 147.6 L/h and 0.154 and 7.39 L for the central and peripheral compartments, respectively. Terminal elimination half-life was 22.1 (intravenous) and 25.1 (oral) min. Oral bioavailability was 9.81%. Urine GABA concentrations peaked rapidly returning to baseline levels by 3 h. Horses appeared behaviorally unaffected following oral administration, while sedative-like changes following intravenous administration were transient. Heart rate was increased for 1 h postintravenous administration, and gastrointestinal sounds decreased for approximately 30 min following both intravenous and oral administration. Based on a limited number of horses and time points, exogenously administered GABA does not appear to enter the CSF to an appreciable extent.

  16. Accelerated corrosion of steam generator tubes by solutes concentrated in defects by boiling

    SciTech Connect

    Ashmore, C.B.; Hurdus, M.H.; Mead, A.P.; Silver, P.J.B.

    1987-01-01

    Accelerated corrosion and deposition processes have been studied at defects (holes of 125, 250 and 500 ..mu..m diameter) in steam generator tubes at high heat flux (440-690 kW/m/sup 2/) under realistic conditions (350/sup 0/C, 17.6 MPa). The occurrence of accelerated corrosion and deposition was found to depend on defect geometry, whilst the pattern of corrosion attack and deposition depended on the nature of the solute. Where the depth/diameter ratio of a defect was less than or equal to1 neither accelerated corrosion nor significant deposition was observed. When this ratio was greater than or equal to2 the corrosion rate was increased by up to twenty fold and deposits were formed. Of the four water chemistry situations investigated (AVT, alkali fault, acid sulphate fault, neutral chloride fault), accelerated corrosion was observed in only the alkali and acid sulphate fault cases. In the alkali case, the rate of corrosion increased with distance into a defect. For acid sulphate, corrosion reached a maximum, part way into a defect, and then decreased. The absence of accelerated corrosion under neutral chloride conditions agrees with the findings of other workers. Porous deposits of the least soluble compounds present in the water were formed at the point of maximum entry of water into defects. A cyclic boiling mechanism, with the defect acting as a bubble nucleation site, is best able to explain the observed results. A model based on this mechanism predicts that threshold levels of solute are necessary before concentrated solutions can be formed in defects.

  17. Selection rules of high-order-harmonic generation: Symmetries of molecules and laser fields

    NASA Astrophysics Data System (ADS)

    Liu, Xi; Zhu, Xiaosong; Li, Liang; Li, Yang; Zhang, Qingbin; Lan, Pengfei; Lu, Peixiang

    2016-09-01

    The selection rules of high harmonic generation (HHG) are investigated using three-dimensional time-dependent density functional theory (TDDFT). From the harmonic spectra obtained with various real molecules and different forms of laser fields, several factors that contribute to selection rules are revealed. Extending the targets to stereoscopic molecules, it is shown that the allowed harmonics are dependent on the symmetries of the projections of molecules. For laser fields, the symmetries contributing to the selection rules are discussed according to Lissajous figures and their dynamical directivities. All the phenomena are explained by the symmetry of the full time-dependent Hamiltonian under a combined transformation. We present a systematic study on the selection rules and propose an intuitive method for the judgment of allowed harmonic orders, which can be extended to more complex molecules and various forms of laser pulses.

  18. Selective resolution of photocurrent generating pathways in transition metal dichalcogenides by ultrafast microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Graham, Matthew W.

    2017-02-01

    Presently, there exists no reliable in-situ time-resolved method that selectively isolates both the recombination and escape times relevant to photocurrent generation in the ultrafast regime. Transport based measurements lack the required time resolution, while purely optical measurement give a convoluted weighted-average of all electronic dynamics, offering no selectivity for photocurrent generating pathways. Recently, the ultrafast photocurrent (U-PC) autocorrelation method has successfully measured the rate limiting electronic relaxation processes in materials such as graphene, carbon nanotubes, and transition metal dichalcogenide (TMD) materials. Here, we unambiguously derive and experimentally confirm a generic U-PC response function by simultaneously resolving the transient absorption (TA) and U-PC response for highly-efficient (48% IQE at 0 bias) WSe2 devices and twisted bilayer graphene. Surprisingly, both optical TA and electrical U-PC responses give the same E-field-dependent electronic escape and recombination rates. These rates further accurately quantify a material's intrinsic PC generation efficiency. We demonstrate that the chirality of the incident light impacts the U-PC kinetics, suggesting such measurements directly access the ultrafast dynamics need to complex electronic physics such as the valley-Hall effect. By combining E-field dependent ultrafast photocurrent with transient absorption microscopy, we have selectively imaged the dominant kinetic bottlenecks that inhibit photocurrent production in devices made from stacked few-layer TMD materials. This provides a new methodology to intelligently select materials that intrinsically avoid recombination bottlenecks and maximize photocurrent yield.

  19. 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

  20. Selection-independent generation of gene knockout mouse embryonic stem cells using zinc-finger nucleases.

    PubMed

    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.

  1. Determination of the influence of substrate concentration on enzyme selectivity using whey protein Isolate and Bacillus licheniformis protease.

    PubMed

    Butré, Claire I; Sforza, Stefano; Gruppen, Harry; Wierenga, Peter A

    2014-10-22

    Increasing substrate concentration during enzymatic protein hydrolysis results in a decrease in hydrolysis rate. To test if changes in the mechanism of hydrolysis also occur, the enzyme selectivity was determined. The selectivity is defined quantitatively as the relative rate of hydrolysis of each cleavage site in the protein. It was determined from the identification and quantification of the peptides present in the hydrolysates. Solutions of 0.1-10% (w/v) whey protein isolate (WPI) were hydrolyzed by Bacillus licheniformis protease at constant enzyme-to-substrate ratio. The cleavage sites were divided into five groups, from very high (>10%) to very low selectivity (<0.1%). The selectivity toward cleavage sites after Glu 62 and 134 was 2 times higher at 10% (w/v) WPI than at the lower protein concentrations. This finding shows that both the rate of hydrolysis and the enzyme selectivity were influenced by the substrate concentration.

  2. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part I: technological concepts and evolution.

    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 geared to simplified preparation without biochemical blood handling. In this initial article, we describe the conceptual and technical evolution from fibrin glues to platelet concentrates. This retrospective analysis is necessary for the understanding of fibrin technologies and the evaluation of the biochemical properties of 3 generations of surgical additives, respectively fibrin adhesives, concentrated platelet-rich plasma (cPRP) and PRF. Indeed, the 3-dimensional fibrin architecture is deeply dependent on artificial clinical polymerization processes, such as massive bovine thrombin addition. Currently, the slow polymerization during PRF preparation seems to generate a fibrin network very similar to the natural one. Such a network leads to a more efficient cell migration and proliferation and thus cicatrization.

  3. Effects of Apple Juice Concentrate, Blackcurrant Concentrate and Pectin Levels on Selected Qualities of Apple-Blackcurrant Fruit Leather

    PubMed Central

    Diamante, Lemuel M.; Li, Siwei; Xu, Qianqian; Busch, Janette

    2013-01-01

    A study was conducted to determine the effects of different levels of apple juice concentrate (AJC), blackcurrant concentrate (BCC) and pectin on the moisture content, water activity, color, texture and ascorbic acid content of apple-blackcurrant fruit leather using the response surface methodology. The results showed the moisture content increased with increasing pectin level and with greater increases at higher AJC and BCC levels while the water activity increased with increasing pectin level and with increasing AJC level, at low pectin levels, but with decreasing AJC, at high pectin levels. The chroma decreased with increasing pectin level and with lower values at the middle AJC level. The puncturing force decreased with increasing AJC level but with a lower value at the middle pectin level. Lastly, the ascorbic acid content increased with increasing BCC level regardless of AJC and pectin levels. There is a need to reduce the drying temperature or time of apple-blackcurrant fruit leather just enough to bring the water activity closer to 0.60, thereby increasing the moisture content resulting in higher product yield. PMID:28239127

  4. Role of selected amino acids on plasma IGF-I concentration in infants.

    PubMed

    Fleddermann, Manja; Demmelmair, Hans; Grote, Veit; Bidlingmaier, Martin; Grimminger, Philipp; Bielohuby, Maximilian; Koletzko, Berthold

    2017-03-01

    Insulin-like growth factor-I (IGF-I) is related to growth and its secretion is modified by protein intake in early infancy. We examined the relationship of dietary protein and circulating amino acids on plasma IGF-I levels and early growth. Healthy formula-fed infants (n = 213) were randomly assigned to receive either a protein-reduced infant formula with alpha-lactalbumin-enriched whey and free tryptophan and phenylalanine (IF) or an isocaloric standard formula without free amino acids (CF) for the first 120 days of life. A group of breastfed (BF) infants was studied as a non-randomized reference cohort. Biochemical variables were measured shortly after birth (subpopulation) and at an age of 120 days. A path analysis was used to explore the relationship between IGF-I, insulin and amino acids. Results are derived from secondary analyses of a randomized controlled trial. Plasma concentrations of IGF-I at 120 days were significantly higher in IF than in CF infants [58.5 (15.0) vs. 53.7 (9.95) ng/mL; p = 0.020]. BF infants showed lower IGF-I concentrations of 41.6 (10.7) ng/mL. All amino acids but Thr and Cit had a more marked effect on insulin than on IGF-I level. Considering weight, sex and feeding group, Trp explained an equal percentage of variance of IGF-I and insulin (total R (2) 12.5 % of IGF-I and 12.3 % of insulin), while branched-chain AA explained an up to twofold higher variance of insulin than IGF-I. Compared to CF, IF explained 18.9 % of the IGF-I level (p = 0.03), while for insulin no direct effect was detectable. Higher IGF-I concentrations and growth velocities in infants receiving protein-reduced IF indicate that the protein concentration of an infant formula alone does not control IGF-I levels and growth. Other components (e.g., selected amino acids) of infant formulae might control directly or indirectly via insulin influence IGF-I.

  5. 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.

  6. Elevated CO2 and O3t concentrations differentially affect selected groups of the fauna in temperate forest soils

    Treesearch

    Gladys I. Loranger; Kurt S. Pregitzer; John S. King

    2004-01-01

    Rising atmospheric CO2 concentrations may change soil fauna abundance. How increase of tropospheric ozone (O3t) concentration will modify these responses is still unknown. We have assessed independent and interactive effects of elevated [CO2] and [O3t] on selected groups of soil...

  7. Measuring zinc in living cells. A new generation of sensitive and selective fluorescent probes.

    PubMed

    Gee, K R; Zhou, Z-L; Ton-That, D; Sensi, S L; Weiss, J H

    2002-05-01

    New fluorescent indicators with nanomolar to micromolar affinities for Zn(2+) have been synthesized in wavelengths from UV to the far red. The UV light-excited indicators are ratiometric. The visible wavelength indicators are non-ratiometric and exhibit large and pH-independent fluorescence increases with increasing zinc concentrations, with little to no sensitivity to physiologically relevant Ca(2+) concentrations. Experiments in neuronal and non-neuronal cell cultures show the new indicators to retain their sensitivity to and selectivity for zinc after conversion to cell-permeable forms. (c) 2002 Elsevier Science Ltd. All rights reserved.

  8. Eleven generations of selection for the duration of fertility in the intergeneric crossbreeding of ducks.

    PubMed

    Cheng, Yu-Shin; Rouvier, Roger; Liu, Hsiao-Lung; Huang, Shang-Chi; Huang, Yu-Chia; Liao, Chung-Wen; Liu Tai, Jui-Jane; Tai, Chein; Poivey, Jean-Paul

    2009-03-31

    A 12-generation selection experiment involving a selected line (S) and a control line (C) has been conducted since 1992 with the aim of increasing the number of fertile eggs laid by the Brown Tsaiya duck after a single artificial insemination (AI) with pooled Muscovy semen. On average, 28.9% of the females and 17.05% of the males were selected. The selection responses and the predicted responses showed similar trends. The average predicted genetic responses per generation in genetic standard deviation units were 0.40 for the number of fertile eggs, 0.45 for the maximum duration of fertility, and 0.32 for the number of hatched mule ducklings' traits. The fertility rates for days 2-8 after AI were 89.14% in the S line and 61.46% in the C line. Embryo viability was not impaired by this selection. The largest increase in fertility rate per day after a single AI was observed from d5 to d11. In G12, the fertility rate in the selected line was 91% at d2, 94% at d3, 92% at days 3 and 4 then decreased to 81% at d8, 75% at d9, 58% at d10 and 42% at d11. In contrast, the fertility rate in the control line showed an abrupt decrease from d4 (74%). The same tendencies were observed for the evolution of hatchability according to the egg set rates. It was concluded that selection for the number of fertile eggs after a single AI with pooled Muscovy semen could effectively increase the duration of the fertile period in ducks and that research should now be focused on ways to improve the viability of the hybrid mule duck embryo.

  9. Eleven generations of selection for the duration of fertility in the intergeneric crossbreeding of ducks

    PubMed Central

    Cheng, Yu-Shin; Rouvier, Roger; Liu, Hsiao-Lung; Huang, Shang-Chi; Huang, Yu-Chia; Liao, Chung-Wen; Liu Tai, Jui-Jane; Tai, Chein; Poivey, Jean-Paul

    2009-01-01

    A 12-generation selection experiment involving a selected line (S) and a control line (C) has been conducted since 1992 with the aim of increasing the number of fertile eggs laid by the Brown Tsaiya duck after a single artificial insemination (AI) with pooled Muscovy semen. On average, 28.9% of the females and 17.05% of the males were selected. The selection responses and the predicted responses showed similar trends. The average predicted genetic responses per generation in genetic standard deviation units were 0.40 for the number of fertile eggs, 0.45 for the maximum duration of fertility, and 0.32 for the number of hatched mule ducklings' traits. The fertility rates for days 2–8 after AI were 89.14% in the S line and 61.46% in the C line. Embryo viability was not impaired by this selection. The largest increase in fertility rate per day after a single AI was observed from d5 to d11. In G12, the fertility rate in the selected line was 91% at d2, 94% at d3, 92% at days 3 and 4 then decreased to 81% at d8, 75% at d9, 58% at d10 and 42% at d11. In contrast, the fertility rate in the control line showed an abrupt decrease from d4 (74%). The same tendencies were observed for the evolution of hatchability according to the egg set rates. It was concluded that selection for the number of fertile eggs after a single AI with pooled Muscovy semen could effectively increase the duration of the fertile period in ducks and that research should now be focused on ways to improve the viability of the hybrid mule duck embryo. PMID:19335901

  10. 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

  11. 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

    2016-03-07

    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.

  12. Evaluation of measured and predicted environmental concentrations of selected human pharmaceuticals and personal care products.

    PubMed

    Liebig, Markus; Moltmann, Johann F; Knacker, Thomas

    2006-03-01

    In the past few years, there was an increasing awareness of the occurrence of pharmaceuticals and personal care products (PPCPs) in surface water and drinking water resources, and measurements in surface water, sediment or waste water were done for a number of PPCPs. In the regulatory context, an environmental risk assessment (ERA) has become essential for new PPCPs. Reliably predicted or measured environmental concentrations (PECs or MECs) of chemicals are essential for the exposure assessment, which is one of the two main pillars of environmental risk assessment (ERA). This paper reports on measured data of selected PPCPs in surface waters and compares the measured values with predicted environmental concentrations from exposure models. Such models have been proposed by the European Agency for the Evaluation of Medicinal Products (EMEA) and the Technical Guidance Document on Risk Assessment for New Notified and Existing Chemical Substances (TGD). Four pharmaceuticals and one personal care product were in the scope of the investigation reported here: 17alpha-ethinylestradiol, carbamazepine, sulfamethoxazole and iopromide as well as tonalide. Measured environmental concentrations in surface waters for these PPCPs were reviewed in the scientific literature. The appropriateness of these data was evaluated according to criteria for monitoring data recommended by the TGD. A total of 38 references were evaluated with emphasis on the adequacy of chemical analysis and the representativeness of sampling. Measurements of concentrations in surface water (MECsw), which were found to be adequate for use in exposure assessment according to the monitoring quality criteria, were averaged and compared with respective PECs in surface water (PECsw) derived from exposure modelling (cf. EMEA and TGD). Measured environmental concentrations adequate for use in exposure assessment were found in 20 out of 38 references. Several of the measurements from Germany could be used for a

  13. Study of EHD flow generator's efficiencies utilizing pin to single ring and multi-concentric rings electrodes

    NASA Astrophysics Data System (ADS)

    Sumariyah; Kusminart; Hermanto, A.; Nuswantoro, P.

    2016-11-01

    EHD flow or ionic wind yield corona discharge is a stream coming from the ionized gas. EHD is generated by a strong electric field and its direction follows the electric field lines. In this study, the efficiency of the EHD flow generators utilizing pin-multi concentric rings electrodes (P-MRE) and the EHD pin-single ring electrode (P-SRE) have been measured. The comparison of efficiencies two types of the generator has been done. EHD flow was generated by using a high-voltage DC 0-10 KV on the electrode pin with a positive polarity and electrode ring/ multi-concentric rings of negative polarity. The efficiency was calculated by comparison between the mechanical power of flow to the electrical power that consumed. We obtained that the maximum efficiency of EHD flow generator utilizing pin-multi concentric rings electrodes was 0.54% and the maximum efficiency of EHD flow generator utilizing a pin-single ring electrode was 0.23%. Efficiency of EHD with P-MRE 2.34 times Efficiency of EHD with P-SRE

  14. High performance concentrating photovoltaic module designs for utility scale power generation

    NASA Astrophysics Data System (ADS)

    Plesniak, Adam; Jones, Russ; Schwartz, Joel; Martins, Guy; Hall, John; Narayanan, Authi; Whelan, David; Benítez, Pablo; Miñano, Juan C.; Cvetkovic, Aleksandra; Hernandez, Maikel; Dross, Oliver; Alvarez, Roberto

    2009-08-01

    The Boeing Company Phantom Works has developed three different prototype photovoltaic concentrator arrays since March 2007. Identified as Prototype A, B and C, the experimentally proven technical characteristics of each design are presented. The concentrator designs utilize a 1 cm2 multi-junction solar cell assembly in conjunction with SMS non-imaging optical designs [1, 2] manufactured with low-cost mass-producible technologies. Prototype A is an on-axis XR optical concentrator with a 733x geometrical concentration demonstrating a +/- 1.73° acceptance angle and 23.7% conversion efficiency. Prototype B is an off-axis free-form XR optical concentrator with a 810x geometrical concentration demonstrating a +/- 1.32° acceptance angle and 25.3% conversion efficiency. Prototype C is the most recent off-axis free-form XR optical concentrator with a 801x geometrical concentration and a theoretical +/-1.80° acceptance angle demonstrating a conversion efficiency greater than 27.0%. Prototype C is also the basis for the Boeing Proof of Design (POD) module, demonstrating an acceptance angle of +/-1.48° and a conversion efficiency of 29.4% (as of May 8, 2009). Manufacturability has been paramount during the design process, resulting in high performance concentrating photovoltaic modules using production quality components.

  15. Concentric-Electrode Organic Electrochemical Transistors: Case Study for Selective Hydrazine Sensing

    PubMed Central

    Pecqueur, Sébastien; Lenfant, Stéphane; Guérin, David; Alibart, Fabien; Vuillaume, Dominique

    2017-01-01

    We report on hydrazine-sensing organic electrochemical transistors (OECTs) with a design consisting of concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based OECTs have been studied as aqueous sensors that are specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10−5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for nine other water-soluble common analytes, the capability to entirely recover its base signal after water flushing, and a very low operation voltage. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode, and enables an increase in the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm, and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device—more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talk, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore further promote the development of OECT biosensors. PMID:28287475

  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. Spatiotemporal pH dynamics in concentration polarization near ion-selective membranes.

    PubMed

    Andersen, Mathias B; Rogers, David M; Mai, Junyu; Schudel, Benjamin; Hatch, Anson V; Rempe, Susan B; Mani, Ali

    2014-07-08

    We present a detailed analysis of the transient pH dynamics for a weak, buffered electrolyte subject to voltage-driven transport through an ion-selective membrane. We show that pH fronts emanate from the concentration polarization zone next to the membrane and that these propagating fronts change the pH in the system several units from its equilibrium value. The analysis is based on a 1D model using the unsteady Poisson-Nernst-Planck equations with nonequilibrium chemistry and without assumptions of electroneutrality or asymptotically thin electric double layers. Nonequilibrium chemical effects, especially for water splitting, are shown to be important for the dynamical and spatiotemporal evolution of the pH fronts. Nonetheless, the model also shows that at steady state the assumption of chemical equilibrium can still lead to good approximations of the global pH distribution. Moreover, our model shows that the transport of the hydronium ion in the extended space charge region is governed by a balance between electromigration and water self-ionization. On the basis of this observation, we present a simple model showing that the net flux of the hydronium ion is proportional to the length of the extended space charge region and the water self-ionization rate. To demonstrate these effects in practice, we have adopted the experiment of Mai et al. (Mai, J.; Miller, H.; Hatch, A. V. Spatiotemporal Mapping of Concentration Polarization Induced pH Changes at Nanoconstrictions. ACS Nano 2012, 6, 10206) as a model problem, and by including the full chemistry and transport, we show that the present model can capture the experimentally observed pH fronts. Our model can, among other things, be used to predict and engineer pH dynamics, which can be essential to the performance of membrane-based systems for biochemical separation and analysis.

  18. Concentric-Electrode Organic Electrochemical Transistors: Case Study for Selective Hydrazine Sensing.

    PubMed

    Pecqueur, Sébastien; Lenfant, Stéphane; Guérin, David; Alibart, Fabien; Vuillaume, Dominique

    2017-03-11

    We report on hydrazine-sensing organic electrochemical transistors (OECTs) with a design consisting of concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based OECTs have been studied as aqueous sensors that are specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10(-5) M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for nine other water-soluble common analytes, the capability to entirely recover its base signal after water flushing, and a very low operation voltage. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode, and enables an increase in the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm, and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device-more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talk, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore further promote the development of OECT biosensors.

  19. Selective photoinactivation of protein function through environment-sensitive switching of singlet oxygen generation by photosensitizer.

    PubMed

    Yogo, Takatoshi; Urano, Yasuteru; Mizushima, Akiko; Sunahara, Hisato; Inoue, Takanari; Hirose, Kenzo; Iino, Masamitsu; Kikuchi, Kazuya; Nagano, Tetsuo

    2008-01-08

    Chromophore-assisted light inactivation is a promising technique to inactivate selected proteins with high spatial and temporal resolution in living cells, but its use has been limited because of the lack of a methodology to prevent nonspecific photodamage in the cell owing to reactive oxygen species generated by the photosensitizer. Here we present a design strategy for photosensitizers with an environment-sensitive off/on switch for singlet oxygen ((1)O(2)) generation, which is switched on by binding to the target, to improve the specificity of protein photoinactivation. (1)O(2) generation in the unbound state is quenched by photoinduced electron transfer, whereas (1)O(2) generation can occur in the hydrophobic environment provided by the target protein, after specific binding. Inositol 1,4,5-trisphosphate receptor, which has been suggested to have a hydrophobic pocket around the ligand binding site, was specifically inactivated by an environment-sensitive photosensitizer-conjugated inositol 1,4,5-trisphosphate receptor ligand without (1)O(2) generation in the cytosol of the target cells, despite light illumination, demonstrating the potential of environment-sensitive photosensitizers to allow high-resolution control of generation of reactive oxygen species in the cell.

  20. 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.

  1. 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.

  2. Day-to-day variability of blood glucose concentration curves generated at home in cats with diabetes mellitus.

    PubMed

    Alt, Nina; Kley, Saskia; Haessig, Michael; Reusch, Claudia E

    2007-04-01

    To evaluate day-to-day variability in blood glucose curves (BGCs) generated at home and at the clinic for cats with diabetes mellitus. Prospective study. 7 cats with diabetes mellitus. Procedures-BGCs generated at home on 2 consecutive days and within 1 week at the clinic were obtained twice. On each occasion, insulin dose, amount of food, and type of food were consistent for all 3 BGCs. Results of curves generated at home were compared with each other and with the corresponding clinic curve. Differences between blood glucose concentration determined after food was withheld (fasting), nadir concentration, time to nadir concentration, maximum concentration, and mean concentration during 12 hours had high coefficients of variation, as did the difference between fasting blood glucose and nadir concentrations and area under the curve of home curves. Differences between home curve variables were not smaller than those between home and clinic curves, indicating large day-to-day variability in both home and clinic curves. Evaluation of the paired home curves led to the same theoretical recommendation for adjustment of insulin dose on 6 of 14 occasions, and evaluation of home and clinic curves resulted in the same recommendation on 14 of 28 occasions. Four of the 6 paired home curves in cats with good glycemic control and 2 of the 8 paired home curves in cats with poor glycemic control led to the same recommendation. Considerable day-to-day variability was detected in BGCs generated at home. Cats with good glycemic control may have more reproducible curves generated during blood collection at home than cats with poorer control.

  3. Salience: the key to the selection problem in natural language generation

    SciTech Connect

    Conklin, E.J.; McDonald, D.D.

    1982-01-01

    The authors argue that in domains where a strong notion of salience can be defined, it can be used to provide: (1) an elegant solution to the selection problem, i.e. the problem of how to decide whether a given fact should or should not be mentioned in the text; and (2) a simple and direct control framework for the entire deep generation process, coordinating proposing, planning, and realization. (Deep generation involves reasoning about conceptual and rhetorical facts, as opposed to the narrowly linguistic reasoning that takes place during realization.) The authors report on an empirical study of salience in pictures of natural scenes, and its use in a computer program that generates descriptive paragraphs comparable to those produced by people. 13 references.

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

    PubMed

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

    2008-12-09

    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 LC(50) 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.

  5. 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

  6. 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.

  7. Generation of marker-free plastid transformants using a transiently cointegrated selection gene.

    PubMed

    Klaus, Sebastian M J; Huang, Fong-Chin; Golds, Timothy J; Koop, Hans-Ulrich

    2004-02-01

    Genetic engineering of higher plant plastids typically involves stable introduction of antibiotic resistance genes as selection markers. Even though chloroplast genes are maternally inherited in most crops, the possibility of marker transfer to wild relatives or microorganisms cannot be completely excluded. Furthermore, marker expression can be a substantial metabolic drain. Therefore, efficient methods for complete marker removal from plastid transformants are necessary. One method to remove the selection gene from higher plant plastids is based on loop-out recombination, a process difficult to control because selection of homoplastomic transformants is unpredictable. Another method uses the CRE/lox system, but requires additional retransformation and sexual crossing for introduction and subsequent removal of the CRE recombinase. Here we describe the generation of marker-free chloroplast transformants in tobacco using the reconstitution of wild-type pigmentation in combination with plastid transformation vectors, which prevent stable integration of the kanamycin selection marker. One benefit of a procedure using mutants is that marker-free plastid transformants can be produced directly in the first generation (T0) without retransformation or crossing.

  8. 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.

  9. Dissolved concentrations, sources, and risk evaluation of selected metals in surface water from Mangla Lake, Pakistan.

    PubMed

    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 (HQ(ing/derm)) and Hazard Index (HI(ing/derm)) following USEPA methodology. For adults and children, Cd, Co, Cr, and Pb (HQ(ing) > 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.

  10. 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

  11. Selective effects of whey protein concentrate on glutathione levels and apoptosis in rats with mammary tumors.

    PubMed

    Cheng, Shih-Hsuan; Tseng, Yang-Ming; Wu, Szu-Hsien; Tsai, Shih-Meng; Tsai, Li-Yu

    2017-09-01

    Glutathione (GSH) plays an important role in antioxidant defense and regulation of apoptosis. GSH deficiency is related to many diseases, including cancer, and increased GSH levels in cancer cells are associated with chemotherapy resistance because of resistance to apoptosis. In this study, we investigated the effects of whey protein concentrate (WPC), a precursor of GSH, in rats with mammary tumors induced by treatment with 7,12-dimethylbenz(a)anthracene (DMBA). DMBA treatment results in cellular changes that mimic the initiation and promotion of carcinogenesis of breast tissue. We aimed to examine the possible preventive effects of diets containing whey protein on DMBA-induced mammary tumors in rats. The results indicate that WPC (0.334 g/kg) supplementation significantly increased the liver GSH levels by 92%, and were accompanied by low Bax/Bcl-2 ratio (from 5 to 3) and cleaved caspase-3/procaspase-3 ratio (from 2.4 to 1.2) in DMBA-treated rats. Furthermore, tumor GSH levels were decreased by 47% in WPC-supplemented rats, which resulted in increased Bax/Bcl-2 ratio (from 0.9 to 2) and cleaved caspase-3/procaspase-3 ratio (from 1.1 to 2.7). In conclusion, supplementation with WPC could selectively deplete tumor GSH levels and, therefore, WPC supplementation might be a promising strategy to overcome treatment resistance in cancer therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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

  13. Exposures to a selective serotonin reuptake inhibitor (SSRI), sertraline hydrochloride, over multiple generations: changes in life history traits in Ceriodaphnia dubia.

    PubMed

    Lamichhane, Kiran; Garcia, Santos N; Huggett, Duane B; Deangelis, Donald L; La Point, Thomas W

    2014-03-01

    Selective serotonin reuptake inhibitors (SSRIs) have been reported to range from low parts per trillion to parts per billion levels in surface waters, wastewater effluents, and sediments. These low levels have led to concern for their potential long-term risks to the survival, growth, and reproduction of aquatic organisms. We investigated the acute and chronic effects of sertraline on the life history traits of Ceriodaphnia dubia over the course of three generations under environmentally realistic concentrations. Acute toxicity of sertraline in C. dubia offspring resulted in a 48h median effective concentration of 126µgL(-1). Under chronic exposure, the lowest concentration to affect fecundity and growth was at 53.4µgL(-1) in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8µgL(-1). The median effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2µgL(-1), respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to sertraline leads to effects that occur at concentrations only an order of magnitude higher than predicted environmental concentrations. However, this study also demonstrates that multigenerational effects should be considered in chronic exposure studies because standard toxicity tests do not account for increases in sensitivity in successive generations to toxicants.

  14. 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

  15. Selective oxidation of low-concentration coal mine gas to methanol in oleum over PbSO4 catalyst

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Li, Fan; Zhu, Li-Hua; Wu, Yang

    2017-06-01

    Selective oxidation of low-concentration coal mine gas to methanol was carried out over PbSO4 catalyst in a concentration of 20% oleum. The effects of reaction temperature, reaction pressure, reaction time and catalyst dosage on the conversion of methane in gas as well as the yield of methanol were studied. What is more, the reaction mechanism of selective oxidation of low-concentration coal mine gas was also investigated. The results showed that the optimal reaction conditions are determined under the reaction temperature of 180°, the reaction pressure of 5MPa, the reaction time of 3h, and the PbSO4 dosage of 300μmol for selective oxidation of low-concentration coal mine gas to methanol by PbSO4 catalyst in oleum. Under this technological condition, the conversion ratio of methane in gas is 8.56% while the methanol selectivity is 78.59%. Mechanism research showed that methane in gas is transformed into methyl bisulfate firstly. Besides, the methyl bisulfate is hydrolyzed into methanol. The selective oxidation of low-concentration coal mine gas is following the mechanism of electrophilic substitution.

  16. Excluded volume effects caused by high concentration addition of acid generators in chemically amplified resists used for extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Watanabe, Kyoko; Matsuoka, Kyoko; Yamamoto, Hiroki; Komuro, Yoshitaka; Kawana, Daisuke; Yamazaki, Akiyoshi

    2017-08-01

    The resolution of lithography used for the high-volume production of semiconductor devices has been improved to meet the market demands for highly integrated circuits. With the reduction in feature size, the molecular size becomes non-negligible in the resist material design. In this study, the excluded volume effects caused by adding high-concentration acid generators were investigated for triphenylsulfonium nonaflate. The resist film density was measured by X-ray diffractometry. The dependences of absorption coefficient and protected unit concentration on acid generator weight ratio were calculated from the measured film density. Using these values, the effects on the decomposition yield of acid generators, the protected unit fluctuation, and the line edge roughness (LER) were evaluated by simulation on the basis of sensitization and reaction mechanisms of chemically amplified extreme ultraviolet resists. The positive effects of the increase in acid generator weight ratio on LER were predominant below the acid generator weight ratio of 0.3, while the negative effects became equivalent to the positive effects above the acid generator weight ratio of 0.3 owing to the excluded volume effects.

  17. Response selection in dual task paradigms: observations from random generation tasks.

    PubMed

    Dirnberger, Georg; Jahanshahi, Marjan

    2010-03-01

    Performance of attention-demanding tasks is worse if two tasks are carried out simultaneously than if each of the tasks is performed alone. Our aim was to determine whether these 'dual task costs' can be attributed to mechanisms on a supra-trial level such as switching of limited resources between trials or concurrent breakdown of supervisory functions, or to mechanisms effective within each trial such as demands of response selection. Twenty healthy volunteers performed verbal random number generation (RNG) and random movement generation (RMG) at three different rates. For each rate, both tasks were examined once in a single task condition and once in a dual task condition. Results showed that performance (quality of randomness) in each random generation task (RNG/RMG) was reduced at faster rates and impaired by concurrent performance of a secondary random generation task. In the dual task condition, transient increase or decrease of bias in one random generation task during any short interval was not associated with concurrent increase or decrease of bias in the other task. In conclusion, the fact that during dual task performance transient bias in one task was not associated with concurrent improvement of performance in the other task indicates that alternation of supervisory control or attentional resources from one to the other task does not mediate the observed dual task costs. Resources of the central executive are not re-allocated or 'switched' from one to the other task. Dual task costs may result from mechanisms effective within each trial such as the demands of response selection.

  18. 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 %).

  19. Influence of high carbon monoxide concentration on the carbon dioxide gasification of a selected coal char

    NASA Astrophysics Data System (ADS)

    Tsai, Nancy Ko-Chieh

    2000-11-01

    This study focuses on the effect of high CO concentration on CO2 gasification rates of chars of Illinois #6 coal, a bituminous coal that is industrially important because of its relatively high reactivity and low pollutant emissions. A pressurized thermogravimetric analyzer (PTGA) is used to obtain char gasification mass loss and surface area measurements. The mass loss profiles of Illinois #6 chars were measured at temperatures of 1200 and 1273K and pressures of 1.4, 10, and 25 atm in CO2-CO and CO2-N2 mixtures. CO concentrations between 10%--90% at 1.4 atm and 10%--85% at 25 atm were used. The surface areas of the chars are determined from room-temperature (298K) CO2 adsorption on chars after successive stages of partial gasification. A variable partial pressure gas adsorption technique was developed to effectively utilize the PTGA for CO2 surface area measurements. Using experimental mass loss and surface area data combined with structural and kinetics modeling, an overall gasification curve description of kinetically-limited char-CO2 gasification reactivity is formulated for the life span of the char. The model consists of an intrinsic char reactivity expression with a conversion-dependent surface area modifier. First the surface area modifier is developed based on a random pore model and particle mode of burning relations. It is used with the unified gasification curve concept to interpret the isothermal gasification profiles and extrapolate the data to obtain the reactivity at the onset of char conversion. These isothermal initial char reactivities determined at selected gasification conditions are then used to calculate rate coefficients in the kinetics component of the model. The proposed reaction mechanism contains paths for both gas phase and adsorbed CO to interfere with the gasification of Illinois #6 chars by CO 2. The main effect of adsorbed CO in the range of experimental conditions used in this study is to occupy carbon sites that could otherwise be

  20. Effect of environmentally-relevant concentrations of nonylphenol on sexual differentiation in zebrafish: a multi-generational study

    NASA Astrophysics Data System (ADS)

    Sun, Dong; Chen, Qi; He, Ning; Diao, Pan-Pan; Jia, Li-Xing; Duan, Shun-Shan

    2017-02-01

    Nonylphenol (NP) is a persistent environmental chemical that can disrupt the organism’s endocrine system, and is detected in the surface water and sea. In this study, we investigated whether NP can alter transcriptional expression of sexual differentiation-related genes. Three generations of zebrafish were exposed to 0, 2, 20 and 200 μg·L‑1 of NP, and transcriptional expression of sexual differentiation genes were assessed in 10, 20 and 40 dpf in the F1 and F2 generations. Growth of zebrafish exposed to 200 μg·L‑1 of NP was inhibited at 125 dpf in the F1 generation. 20 μg·L‑1 of NP resulted in 80% females in the F1 generation, but had no effect on the F2 generation. In terms of the sexual differentiation genes, the transcriptional expression of cyp19a1a and esr1 genes were upregulated in 20 μg·L‑1 of NP in the F1 generation. But expression of the sexual differentiation genes were not affected in the F2 generation. Overall, NP could affect sexual differentiation and gene transcriptional expression in the F1 generation. The tolerance of contaminant in the offsprings was improved at low concentration.

  1. Effect of environmentally-relevant concentrations of nonylphenol on sexual differentiation in zebrafish: a multi-generational study

    PubMed Central

    Sun, Dong; Chen, Qi; He, Ning; Diao, Pan-pan; Jia, Li-xing; Duan, Shun-shan

    2017-01-01

    Nonylphenol (NP) is a persistent environmental chemical that can disrupt the organism’s endocrine system, and is detected in the surface water and sea. In this study, we investigated whether NP can alter transcriptional expression of sexual differentiation-related genes. Three generations of zebrafish were exposed to 0, 2, 20 and 200 μg·L−1 of NP, and transcriptional expression of sexual differentiation genes were assessed in 10, 20 and 40 dpf in the F1 and F2 generations. Growth of zebrafish exposed to 200 μg·L−1 of NP was inhibited at 125 dpf in the F1 generation. 20 μg·L−1 of NP resulted in 80% females in the F1 generation, but had no effect on the F2 generation. In terms of the sexual differentiation genes, the transcriptional expression of cyp19a1a and esr1 genes were upregulated in 20 μg·L−1 of NP in the F1 generation. But expression of the sexual differentiation genes were not affected in the F2 generation. Overall, NP could affect sexual differentiation and gene transcriptional expression in the F1 generation. The tolerance of contaminant in the offsprings was improved at low concentration. PMID:28230098

  2. In vitro comparison of the effect of two factor XI (FXI) concentrates on thrombin generation in major FXI deficiency.

    PubMed

    Pike, G N; Cumming, A M; Hay, C R M; Sempasa, B; Sutherland, M; Thachil, J; Burthem, J; Bolton-Maggs, P H B

    2016-05-01

    Bleeding risk in factor XI (FXI) deficiency following surgery may be reduced by treatment with either of two FXI concentrates, but indications for their use are unclear and treatment has been associated with thrombosis. To quantify and compare the effects of two different FXI concentrates on thrombin generation (TG) in major FXI deficiency (FXI:C < 15 IU dL(-1) ). Thrombin generation was measured in controls (n = 50), FXI-deficient individuals pre and post in vitro spiking with FXI concentrates (n = 10), and in ex vivo samples following treatment with FXI concentrate (n = 3). Thrombin generation was significantly impaired in FXI deficiency but improved following FXI replacement in vitro and in vivo. LFB Hemoleven(®) had greater effect on TG than BPL FXI concentrate in vitro (equivalent in vivo doses 10, 20 and 30 U kg(-1) ): higher endogenous thrombin potential (ETP) (P < 0.0001), peak height (P < 0.01) velocity (P < 0.0002) and shorter lag time and time to peak (both P < 0.003). Some measurements with LFB Hemoleven(®) exceeded the reference range. At lower dose (5 U kg(-1) ), BPL FXI concentrate normalized all TG parameters and LFB Hemoleven(®) normalized the ETP but exceeded the reference range with other parameters. Both FXI concentrates improve TG in vitro in major FXI deficiency but differ in dose response, and for both products, doses lower than previously recommended normalized TG in vitro. Comparison of in vitro spiked and ex vivo samples suggest that in vitro results could be used to estimate an expected in vivo response to FXI replacement. © 2015 John Wiley & Sons Ltd.

  3. Airborne concentrations of benzene and mineral spirits (stoddard solvent) during cleaning of a locomotive generator and traction motor.

    PubMed

    Madl, Amy K; Paustenbach, Dennis J

    2002-12-13

    Mineral spirits (also called Stoddard solvent), a petroleum distillate, is often used as a degreaser or an industrial cleaning agent. Although several studies measured airborne concentrations of mineral spirits in various occupational settings, none have characterized the airborne concentrations of benzene from use of mineral spirits. Recent case reports have suggested that benzene, as a contaminant in mineral spirits, might be responsible for adverse health effects. Because some claims of health effects in the railroad industry have been attributed to potential historical exposures to mineral spirits and little information is available regarding air concentrations in this type of occupational setting, a simulation study was conducted to quantitate historical exposures a railroad worker might have experienced while spraying mineral spirits on locomotive engine parts in the 1970s. To quantitate potential historical exposures, worker tasks were simulated under worst-case exposure conditions by spraying minerals spirits on a locomotive generator and traction motor. The results of both generator and traction motor cleaning events produced concentrations of mineral spirits ranging from 34 to 221 ppm and an average 1-h concentration of 121 ppm, whereas benzene concentrations associated with the spraying and drying tasks were less than the limit of detection (0.002-0.006 ppm). Results indicate that a railroad worker who cleaned a locomotive traction motor and generator with mineral spirits for 2 h each workday under worst-case exposure conditions would be exposed to an 8-h time-weighted average (based on lapel measurements) of 30.4 ppm airborne mineral spirits. On the basis of the conditions under which these concentrations were obtained, the results should be the reasonable maximum values that can be achieved in a modern-era (post-1970) workplace in the United States.

  4. 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.

  5. Study on tobacco components involved in the pyrolytic generation of selected smoke constituents.

    PubMed

    Torikai, K; Torikaiu, K; Uwano, Y; Nakamori, T; Tarora, W; Takahashi, H

    2005-04-01

    The aim of this study was to investigate the contribution of various tobacco components to the generation of smoke constituents using a tobacco pyrolysis model. We analyzed the amounts of primary tobacco components (sugars, protein, polyphenols, alkaloids, organic acids, inorganics etc.) in flue-cured and burley tobacco leaves. Each of the components was added to the tobacco leaves at the 0.5-fold and 1.0-fold amount naturally present in the leaves. The treated tobacco samples were pyrolyzed at 800 degrees C in a nitrogen atmosphere with an infrared image furnace, and the selected smoke constituents (benzo[a]pyrene, hydrogen cyanide, carbonyl compounds, aromatic amines, volatile organic compounds and phenolics) were quantitatively analyzed by several methods, including high performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC-MS). The contribution of each tobacco component to the generation of selected smoke constituents was estimated from a regression line determined by the three yields (no addition, 0.5-fold addition, and 1.0-fold addition). The results of this study can provide useful and comprehensive information on the relationship between tobacco components and selected smoke constituents during pyrolysis.

  6. Osmotic and diffusio-osmotic flow generation at high solute concentration. I. Mechanical approaches

    NASA Astrophysics Data System (ADS)

    Marbach, Sophie; Yoshida, Hiroaki; Bocquet, Lydéric

    2017-05-01

    In this paper, we explore various forms of osmotic transport in the regime of high solute concentration. We consider both the osmosis across membranes and diffusio-osmosis at solid interfaces, driven by solute concentration gradients. We follow a mechanical point of view of osmotic transport, which allows us to gain much insight into the local mechanical balance underlying osmosis. We demonstrate in particular how the general expression of the osmotic pressure for mixtures, as obtained classically from the thermodynamic framework, emerges from the mechanical balance controlling non-equilibrium transport under solute gradients. Expressions for the rejection coefficient of osmosis and the diffusio-osmotic mobilities are accordingly obtained. These results generalize existing ones in the dilute solute regime to mixtures with arbitrary concentrations.

  7. Water vapor concentration measurement in singlet oxygen generator by using emission spectroscopy method and absorption at 1392nm

    NASA Astrophysics Data System (ADS)

    Zhao, Weili; Wang, Zengqiang; Fang, Benjie; Li, Qingwei; Jin, Yuqi; Sang, Fengting

    2005-12-01

    By using emission spectroscopy method and absorption at 1392nm, partial water pressure at the exit of a square pipe-array jet-type singlet oxygen generator (SPJSOG) for chemical oxygen-iodine laser (COIL) was measured. The water vapor fraction was calculated from the partial water pressure in the diagnostic cell when we assumed the water vapor fraction in the diagnostic cell is the same as that in the generator. The results from the two methods showed that the water vapor concentration is less than 0.08 in this SPJSOG during normal operation. The water vapor fraction decreases with the increasing of the pressure in the generator and rises with the increasing of buffer gas flow rate and the basic hydrogen peroxide (BHP) temperature in the case of constant chlorine flow rate. Measurements showed that the change of water vapor fraction due to BHP temperature could be ignored during normal operation. It is indicated that the gas flow velocity is the main reason that affects on the water vapor fraction in COIL. It is proved that the emission spectroscopy method is one of the simple and convenient ways to measure the water vapor concentration in singlet oxygen generator (SOG), especially in real time measurements. But absorption spectroscopy method, as a direct measurement, can give the more factual results of the water concentration.

  8. Corn stover saccharification with concentrated sulfuric acid: effects of saccharification conditions on sugar recovery and by-product generation.

    PubMed

    Liu, Ze-Shen; Wu, Xiao-Lei; Kida, Kenji; Tang, Yue-Qin

    2012-09-01

    Although concentrated sulfuric acid saccharification is not a novel method for breaking down lignocellulosic biomass, the process by which saccharification affects biomass decomposition, sugar recovery, and by-product generation is not well studied. The present study employed Taguchi experimental design to study the effects of seven parameters on corn stover concentrated sulfuric acid saccharification. The concentration of sulfuric acid and the temperature of solubilization significantly affect corn stover decomposition. They also have significant effects on glucose and xylose recoveries. Low generation of furfural and 5-hydroxymethyl-2-furfural (5HMF) was noted and organic acids were the main by-products detected in the hydrolysate. Temperature also significantly affected the generation of levulinic acid and formic acid; however, acetic acid generation was not significantly influenced by all seven parameters. The ratio of acid to feedstock significantly affected glucose recovery, but not total sugar recovery. The corn stover hydrolysate was well fermented by both glucose- and xylose-fermenting yeast strains. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. 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.

  10. Analysis of response to 20 generations of selection for body composition in mice: fit to infinitesimal model assumptions

    PubMed Central

    Martinez, Victor; Bünger, Lutz; Hill, William G

    2000-01-01

    Data were analysed from a divergent selection experiment for an indicator of body composition in the mouse, the ratio of gonadal fat pad to body weight (GFPR). Lines were selected for 20 generations for fat (F), lean (L) or were unselected (C), with three replicates of each. Selection was within full-sib families, 16 families per replicate for the first seven generations, eight subsequently. At generation 20, GFPR in the F lines was twice and in the L lines half that of C. A log transformation removed both asymmetry of response and heterogeneity of variance among lines, and so was used throughout. Estimates of genetic variance and heritability (approximately 50%) obtained using REML with an animal model were very similar, whether estimated from the first few generations of selection, or from all 20 generations, or from late generations having fitted pedigree. The estimates were also similar when estimated from selected or control lines. Estimates from REML also agreed with estimates of realised heritability. The results all accord with expectations under the infinitesimal model, despite the four-fold changes in mean. Relaxed selection lines, derived from generation 20, showed little regression in fatness after 40 generations without selection. PMID:14736404

  11. 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

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sample selection by random number... § 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 for...

  12. Use of recursively generated intermediates in state selective multireference coupled-cluster method: A numerical example

    SciTech Connect

    Ghose, K.B.; Adamowicz, L.

    1995-12-01

    The present work represents the first attempt to utilize the idea of recursively generated intermediates (RGI) in the framework of the state-selective multi-reference coupled-cluster method truncated at triple excitations [SS CCSD(T)]. The expressions for stepwise generation of intermediates are so structured that the spin and point symmetry simplifications can be easily applied during computation. Suitable modifications in SS CCSD(T) equations are introduced to allow for optional quasilinearization of nonlinear terms in difficult convergence situations. The computational code is, as expected, much faster than the SS CCSD(T) code without RGI adaptation. This has been numerically demonstrated by potential energy surface (PES) calculation of the HF molecule using a double zeta basis. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  13. Connection topology selection in central pattern generators by maximizing the gain of information.

    PubMed

    Stiesberg, Gregory R; Reyes, Marcelo Bussotti; Varona, Pablo; Pinto, Reynaldo D; Huerta, Ramón

    2007-04-01

    A study of a general central pattern generator (CPG) is carried out by means of a measure of the gain of information between the number of available topology configurations and the output rhythmic activity. The neurons of the CPG are chaotic Hindmarsh-Rose models that cooperate dynamically to generate either chaotic or regular spatiotemporal patterns. These model neurons are implemented by computer simulations and electronic circuits. Out of a random pool of input configurations, a small subset of them maximizes the gain of information. Two important characteristics of this subset are emphasized: (1) the most regular output activities are chosen, and (2) none of the selected input configurations are networks with open topology. These two principles are observed in living CPGs as well as in model CPGs that are the most efficient in controlling mechanical tasks, and they are evidence that the information-theoretical analysis can be an invaluable tool in searching for general properties of CPGs.

  14. BAGE genes generated by juxtacentromeric reshuffling in the Hominidae lineage are under selective pressure.

    PubMed

    Ruault, Myriam; Ventura, Mario; Galtier, Nicolas; Brun, Marie-Elisabeth; Archidiacono, Nicoletta; Roizès, Gérard; De Sario, Albertina

    2003-04-01

    In this paper, we show that the BAGE (B melanoma antigen) gene family was generated by chromosome rearrangements that occurred during the evolution of hominoids. An 84-kb DNA fragment derived from the phylogenetic 7q36 region was duplicated in the juxtacentromeric region of either chromosome 13 or chromosome 21. The duplicated region contained a fragment of the MLL3 gene, which, after juxtacentromeric reshuffling, generated the ancestral BAGE gene. Then, this ancestral gene gave rise to several independent genes through successive rounds of inter- and intrachromosome duplications. Comparison of synonymous and nonsynonymous mutations in putative coding regions shows that BAGE genes, but not the BAGE gene fragments, are under selective pressure. Our data strongly suggest that BAGE proteins have a function and that juxtacentromeric regions, whose plasticity is now largely proved, are not a simple junkyard of gene fragments, but may be the birth site of novel genes.

  15. Informing Selection of Nanomaterial Concentrations for ToxCast in Vitro Testing Based on Occupational Exposure Potential

    PubMed Central

    Brown, James S.; Wang, Amy; Houck, Keith A.; Dix, David J.; Kavlock, Robert J.; Hubal, Elaine A. Cohen

    2011-01-01

    Background: 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. Objectives: Our goal was to use estimates of lung deposition after occupational exposure to nanomaterials to recommend in vitro testing concentrations for the U.S. Environmental Protection Agency’s ToxCast™ program. Here, we provide testing concentrations for carbon nanotubes (CNTs) and titanium dioxide (TiO2) and silver (Ag) nanoparticles (NPs). Methods: We reviewed published ENM concentrations measured in air in manufacturing and R&D (research and development) laboratories to identify input levels for estimating ENM mass retained in the human lung using the multiple-path particle dosimetry (MPPD) model. Model input parameters were individually varied to estimate alveolar mass retained for different particle sizes (5–1,000 nm), aerosol concentrations (0.1 and 1 mg/m3), aspect ratios (2, 4, 10, and 167), and exposure durations (24 hr and a working lifetime). The calculated lung surface concentrations were then converted to in vitro solution concentrations. Results: Modeled alveolar mass retained after 24 hr is most affected by activity level and aerosol concentration. Alveolar retention for Ag and TiO2 NPs and CNTs for a working-lifetime (45 years) exposure duration is similar to high-end concentrations (~ 30–400 μg/mL) typical of in vitro testing reported in the literature. Conclusions: Analyses performed are generally applicable for providing ENM testing concentrations for in vitro hazard screening studies, although further research is needed to improve the approach. Understanding the relationship between potential real-world exposures and in vitro test concentrations will facilitate interpretation of toxicological results. PMID:21788197

  16. Thrombin Generation Capacity of Prothrombin Complex Concentrate in an In Vitro Dilutional Model

    PubMed Central

    Grottke, Oliver; Rossaint, Rolf; Henskens, Yvonne; van Oerle, Rene; ten Cate, Hugo; Spronk, Henri M. H.

    2013-01-01

    Background The use of PCC for the treatment of trauma-induced coagulopathy potentially increase the risk of thromboembolism and disseminated intravascular coagulation, which is addressed to an imbalance of both pro- and anticoagulants. As PCCs differ in composition, we used an in vitro dilutional approach to assess the overall thrombin generation of five different PCCs through various laboratory assays. Methods The vitamin K-dependent coagulation factors, heparin, and antithrombin were assessed in five commercially available PCCs. The procoagulant potential of the PCCs was assessed in plasma and whole blood from 4 healthy donors by means of classical coagulation assays, thrombin generation assay and thromboelastometry. In order to reflect coagulopathy, whole blood was diluted to 80, 60, 40, and 20% with Ringer’s lactate solution. Results The five different PCCs were characterised by comparable levels of factors II, VII, IX and X (all around 20–30 IU/mL), whereas the heparin (0 to 17.6 IU/mL) and antithrombin (0.06 to 1.29 IU/mL) levels were remarkably different between manufactures. In vitro dilution of blood induced a prolongation of the PT and aPTT, and attenuation of thrombin generation and ExTem induced thromboelastometry. Overall, non- or low-heparin containing PCCs restored the in vitro dilutional coagulopathy, whereas PCCs containing heparin have an anticoagulant effect. The thrombin generation assay showed to be the most sensitive method for assessment of PCC effects. Conclusions This study shows that most available PCCs are not balanced regarding their pro- and anticoagulants. The effect of measured differences in thrombin generation among different PCCs requires further investigations to elaborate the clinical meaning of this finding in the treatment of trauma induced coagulopathy. PMID:23696866

  17. Bactericidal effect of hydroxyl radicals generated from a low concentration hydrogen peroxide with ultrasound in endodontic treatment.

    PubMed

    Kobayashi, Yoshimi; Hayashi, Makoto; Yoshino, Fumihiko; Tamura, Muneaki; Yoshida, Ayaka; Ibi, Haruna; Lee, Masaichi-Chang-Il; Ochiai, Kuniyasu; Ogiso, Bunnai

    2014-05-01

    One approach to enhance the disinfection of root canals in endodontic treatment is ultrasonic irrigation with sodium hypochlorite. Reactive oxygen species, such as hydroxyl radical, are generated by biological defense systems to kill invading bacteria. Ultrasonic irrigation with hydrogen peroxide may be a promising option to increase hydroxyl radical generation. We examined the bactericidal effects of hydroxyl radical generated from low concentration hydrogen peroxide with ultrasound in vitro. An ultrasonic tip was submerged in 0.5 or 1.0 M hydrogen peroxide in a microfuge tube. hydrogen peroxide was irradiated with the ultrasound, the tip of which was maintained centered in the tube to mimic ultrasonic irrigation. Hydroxyl radical generation was assessed by electron spin resonance spectroscopy. Subsequently, Enterococcus faecalis suspension in hydrogen peroxide was prepared and irradiated as described above. Bactericidal effects were assessed by viable counting. Electron spin resonance measurements showed that hydroxyl radical generation increased significantly in a time- and dose-dependent manner (two-way analysis of variance and Tukey's test, p<0.05). Moreover, the bactericidal effects of hydrogen peroxide against Enterococcus faecalis were enhanced by ultrasonic irradiation in a time- and dose-dependent manner. These results suggest that ultrasonic irrigation in the presence of low concentration hydrogen peroxide can serve as a disinfection strategy in endodontic treatment.

  18. 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.

  19. ATOMIC AND MOLECULAR PHYSICS: Ultra-Slow Atomic Beam Generation by Velocity Selective Resonance

    NASA Astrophysics Data System (ADS)

    Ma, Hong-Yu; Cheng, Hua-Dong; Wang, Yu-Zhu; Liu, Liang; Metcalf, Harold

    2008-05-01

    We describe a method to generate an ultra-slow atomic beam by velocity selective resonance (VSR). A VSR experiment on a metastable helium beam in a magnetic field is presented and the results show that the transverse velocity of the deflected beam can be cooled and precisely controlled to less than the recoil velocity, depending on the magnitude of the magnetic field. We extend this idea to a cold atomic cloud to produce an ultra slow 87Rb beam that can be used as a source of an atomic fountain clock or a space clock.

  20. 25-Hydroxyvitamin D concentrations, asthma and eczema in childhood: The generation R study.

    PubMed

    Tromp, Ilse I M; Franco, Oscar H; van den Hooven, Edith H; Heijboer, Annemieke C; Jaddoe, Vincent W V; Duijts, Liesbeth; de Jongste, Johan C; Moll, Henriëtte A; Kiefte-de Jong, Jessica C

    2016-12-08

    A role of vitamin D in the development of respiratory and allergic disease in children remains unclear. It may be likely that vitamin D has an effect on airway inflammation, but only few studies examined the effect in children. We aimed to examine whether serum 25-hydroxyvitamin D (25(OH) vitamin D) concentrations are associated with the fraction of exhaled nitric oxide (FeNO), airway interrupter resistance (Rint), physician diagnosed asthma ever, wheezing and eczema in a population-based cohort study in 6 year old children. Serum 25(OH) vitamin D concentration was assessed in 3815 children. 25(OH) vitamin D concentrations ≥75 nmol/L were considered as sufficient, between 50 and 75 nmol/L as insufficient, and <50 nmol/L as deficient. FeNO and Rint were measured at the research center. Data on physician diagnosed asthma, wheezing, and eczema were obtained by parent-reported questionnaires. In comparison with sufficient 25(OH) vitamin D concentration, deficient concentrations were associated with elevated FeNO of ≥25 ppb (OR: 2.54; 95% CI: 1.34-4.80). In addition, deficient and insufficient 25(OH) vitamin D concentrations were associated with a lower Rint (Z-score: -1.26; 95% CI: -1.66 to -0.85) (ß: -0.75; 95% CI: -1.08 to -0.42), and increased risks of eczema (OR: 1.65; 95% CI: 1.13-2.41) (OR: 1.44; 95% CI: 1.06-1.95). Insufficient 25(OH) vitamin D concentration were associated with a decreased risk of physician diagnosed asthma ever (OR: 0.59; 95% CI: 0.38-0.94). Our results indicate that lower 25(OH) vitamin D levels are associated with elevated FeNO levels, but lower Rint values. Lower 25(OH) vitamin D levels are also associated with a decreased risk for asthma diagnoses but an increased risk for eczema. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  1. 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.

  2. The Impact of Selectivity on Fitness Evolution in the Multi-Generational Matching Problem

    NASA Astrophysics Data System (ADS)

    Dipple, Stephen; Jia, Tao; Korniss, Gyorgy; Szymanski, Boleslaw

    The stochastic matching hypothesis has been found to produce self-similar pairing without explicitly requiring self-similarity in the rules for matching. Here, we introduce an added complexity of selectivity in which the relative probability of being matched are modified. This allows for probing in areas between the currently established matching hypothesis, random matching, and the extreme case of super selectivity, where only the very best fitness matches for nodes are created. A higher selectivity parameter has been found to indirectly increase the number of matches in the system monotonically. A fairly simple model is then implemented to produce offspring who inherit fitness based on the inherited fitness distribution which is a function of the parents' fitness. While the results show that the specific distribution used may limit the inherited quality factors to a too narrow range to be broadly applicable, the model does expose some interesting patterns in fitness evolution across multiple generations in the context of selectivity and network degree distribution. Supported in part by ARL NS-CTA and ONR.

  3. Detecting Positive Selection of Korean Native Goat Populations Using Next-Generation Sequencing

    PubMed Central

    Lee, Wonseok; Ahn, Sojin; Taye, Mengistie; Sung, Samsun; Lee, Hyun-Jeong; Cho, Seoae; Kim, Heebal

    2016-01-01

    Goats (Capra hircus) are one of the oldest species of domesticated animals. Native Korean goats are a particularly interesting group, as they are indigenous to the area and were raised in the Korean peninsula almost 2,000 years ago. Although they have a small body size and produce low volumes of milk and meat, they are quite resistant to lumbar paralysis. Our study aimed to reveal the distinct genetic features and patterns of selection in native Korean goats by comparing the genomes of native Korean goat and crossbred goat populations. We sequenced the whole genome of 15 native Korean goats and 11 crossbred goats using next-generation sequencing (Illumina platform) to compare the genomes of the two populations. We found decreased nucleotide diversity in the native Korean goats compared to the crossbred goats. Genetic structural analysis demonstrated that the native Korean goat and crossbred goat populations shared a common ancestry, but were clearly distinct. Finally, to reveal the native Korean goat’s selective sweep region, selective sweep signals were identified in the native Korean goat genome using cross-population extended haplotype homozygosity (XP-EHH) and a cross-population composite likelihood ratio test (XP-CLR). As a result, we were able to identify candidate genes for recent selection, such as the CCR3 gene, which is related to lumbar paralysis resistance. Combined with future studies and recent goat genome information, this study will contribute to a thorough understanding of the native Korean goat genome. PMID:27989103

  4. Detecting Positive Selection of Korean Native Goat Populations Using Next-Generation Sequencing.

    PubMed

    Lee, Wonseok; Ahn, Sojin; Taye, Mengistie; Sung, Samsun; Lee, Hyun-Jeong; Cho, Seoae; Kim, Heebal

    2016-12-01

    Goats (Capra hircus) are one of the oldest species of domesticated animals. Native Korean goats are a particularly interesting group, as they are indigenous to the area and were raised in the Korean peninsula almost 2,000 years ago. Although they have a small body size and produce low volumes of milk and meat, they are quite resistant to lumbar paralysis. Our study aimed to reveal the distinct genetic features and patterns of selection in native Korean goats by comparing the genomes of native Korean goat and crossbred goat populations. We sequenced the whole genome of 15 native Korean goats and 11 crossbred goats using next-generation sequencing (Illumina platform) to compare the genomes of the two populations. We found decreased nucleotide diversity in the native Korean goats compared to the crossbred goats. Genetic structural analysis demonstrated that the native Korean goat and crossbred goat populations shared a common ancestry, but were clearly distinct. Finally, to reveal the native Korean goat's selective sweep region, selective sweep signals were identified in the native Korean goat genome using cross-population extended haplotype homozygosity (XP-EHH) and a cross-population composite likelihood ratio test (XP-CLR). As a result, we were able to identify candidate genes for recent selection, such as the CCR3 gene, which is related to lumbar paralysis resistance. Combined with future studies and recent goat genome information, this study will contribute to a thorough understanding of the native Korean goat genome.

  5. 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. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. 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

    2016-08-05

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Development of a selective medium for the determination of the spore concentrations of Botrytis cinerea in the air.

    PubMed

    Gielen, S; Aerts, R; Seels, B

    2003-01-01

    Gray mold, caused by Botrytis cinerea, is an important disease that causes world-wide extensive damage to a wide range of economically important crops. When it is necessary to determine the spore concentration of Botrytis cinerea in a certain area, it is important to develop a method that can capture the spores of Botrytis cinerea and that can identify them. For the identification and enumeration of the plant pathogen Botrytis cinerea in the environment the easiest method available for the moment is the use of a selective medium. Several selective media for the isolation of Botrytis spp. have been developed by other research groups. All these media contain fungicides that are usually non-toxic towards Botrytis species and tannic acid, which is oxidized to produce a brown pigment that visualises the growth of Botrytis cinerea on the selective media. It seemed that different isolates of Botrytis cinerea that are found in nature have different sensitivities towards the different fungicide concentrations that are used in the selective media. Making the "optimal" selective media for Botrytis cinerea, we have to take in consideration that so many as possible Botrytis cinerea isolates must be able to germinate and grow on this selective medium and that the contamination of other micro-organisms on the selective medium must be minimized. Before the final composition of our selective medium for Botrytis cinerea, different combinations of fungicide concentrations were tried out of the following three fungicides: Rubigan, maneb and PCNB (pentachloronitrobenzene). All these selective media with different fungicides concentrations were tested out for spore germination and mycelium growth of Botrytis cinerea. Because it was obvious that the percentage Botrytis cinerea that germinated on PDA (Potato Dextrose Agar) was higher than on the selective medium a few experiments were executed in which the percentage of spore germination on PDA was compared with the percentage of spore

  8. 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

  9. Review of factors impacting emission/concentration of cooking generated particulate matter.

    PubMed

    Amouei Torkmahalleh, Mehdi; Gorjinezhad, Soudabeh; Unluevcek, Hediye Sumru; Hopke, Philip K

    2017-05-15

    Studies have shown that exposure to particulate matter (PM) emitted while cooking is related to adverse human health effects. The level of PM emissions during cooking varies with several factors. This study reviewed controlled studies available in the cooking PM emissions literature, and found that cooking method, type and quality of the energy (heating) source, burner size, cooking pan, cooking oil, food, additives, source surface area, cooking temperature, ventilation and position of the cooking pan on the stove are influential factors affecting cooking PM emission rates and resulting concentrations. Opportunities to reduce indoor PM concentrations during cooking are proposed. Minor changes in cooking habits and manner might result in a substantial reduction in the cook's exposure to the cooking PM. Finally, the need for additional studies is discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Determination of selected heavy metal concentrations and distribution in a southwestern stream using macrophytes.

    PubMed

    Martinez, Edward A; Shu-Nyamboli, Chemanji

    2011-09-01

    Since the reduction of the arsenic standard from 50 to 10 μg L(-1) by the US Environmental Protection Agency in 2006 many small town and rural water municipalities were left with the task of preventing or mitigating arsenic contamination of drinking water supplies. In this study macrophytes and sediments were used to determine the concentration and distribution of heavy metals (As, Cd, Cu, Pb, and Zn) within the primary source of drinking water (Gallinas River watershed) to the residents of Las Vegas, New Mexico. Sampling was done in the spring and fall at four sites, two above the city and two below, and samples were analyzed using ICP-MS. Results showed significantly higher (p<.05) metal concentrations in plant roots than shoots for most metals. Spearman's correlation showed positive correlations (r>.3) between plant and sediment concentrations of Cd, Pb, Zn, As, and a negative correlation for Cu. The site above waste water treatment plant (AWWTP) had the highest plant tissue concentrations of Cd, Pb, Zn, and As. All of these concentrations attained critical toxicity levels exceeding sediment quality guidelines. High concentration factor values and levels of metals detected in macrophyte tissues indicate that heavy metals within sediments in the Gallinas River occur in bioavailable forms. Correlations between plant and sediment metal concentrations indicate that metal concentrations in macrophyte tissues are a good reflection of metal concentrations within the sediment in the Gallinas River. Copyright © 2011 Elsevier Inc. All rights reserved.

  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. Biofilter for generation of concentrated sulphuric acid from H2S.

    PubMed

    Rabbani, K A; Charles, W; Kayaalp, A; Cord-Ruwisch, R; Ho, G

    2016-08-01

    Biofilters are used for the conversion of odorous hydrogen sulphide to odourless sulphate in wastewater treatment plants under the right conditions of moisture and pH. One of the consequences of maintaining the suitable pH and moisture content is the production of large volumes of weakly acidic leachate. This paper presents a biofilter with a maximum H2S elimination capacity of 16.3 g m(-3) h(-1) and removal efficiency greater than 95 % which produces small volumes (1 mL of solution L(-1) of reactor day(-1)) of sulphuric acid with a concentration greater than 5.5 M after 150 days of continuous operation. The concentrated sulphuric acid was produced by intermittently trickling a minimum amount of nutrient solution down the upflow biofilter which created a moisture and pH gradient within the biofilter resulting in an environment at the top for the bacterial conversion of H2S, while sulphuric acid was accumulated at the base. Genetic diversity profiling of samples taken from different sections of the biofilter confirms that the upper sections of the biofilter had the best environment for the bacteria to convert H2S to sulphate. The formation of concentrated sulphuric acid presents an opportunity for the recovery of sulphur from the waste stream as a usable product.

  13. Experiments on solar photovoltaic power generation using concentrator and liquid cooling

    NASA Technical Reports Server (NTRS)

    Beam, B. H.; Hansen, C. F.

    1975-01-01

    Calculations and experimental data are presented leading to the development of a practical, economical solar photovoltaic power supply. The concept involves concentration of sunlight up to about 100 times normal solar intensity in a solar tracking collector and directing this to an array of solar cells. The cells are immersed in water circulated from a thermal reservoir which limits cell temperature rise to about 20 C above ambient during the day and which cools to ambient temperature during the night. Experiments were conducted on solar cells using a Fresnel lens for magnification, a telescope equatorial mount with clock drive, and tap water circulated through the solar cell holder cavity. Test results show that cells operate satisfactorily under these conditions. Power outputs achieved experimentally with cell optimized for 25 suns were linear with concentration to about 15 suns. Cells optimized for 100 suns were not available, but a corresponding linear relation of power output with concentration is anticipated. Test results have been used in a design analysis of the cost of systems utilizing this technique.

  14. Does low uranium concentration generates phytotoxic symptoms in Pisum sativum L. in nutrient medium?

    PubMed

    Tawussi, Frank; Walther, Clemens; Gupta, Dharmendra K

    2017-09-06

    Due to excessive mining and use of radionuclide especially uranium (U) and its fission products, numerous health hazards as well as environmental contamination worldwide have been created. The present study focused on demonstrating whether low concentration of U treatment in liquid nutient medium may translocate traces of U in plants and in fruits of Pisum sativum after 30 and 60 days of exposure for the safe use as a food supplement for human/animals. Hydroponically grown plants (in amended Hoagland medium) were treated with two different concentrations of uranium ([U] = 100 and 500 nM, respectively). Plants showed a decrease in total chlorophyll after 60 days of treatment. On the other hand, Eh of the nutrient medium was not affected from the initial days till 60 days of treatment, but pH of nutrient medium was increased upon durations, highest at 60 days of treatment. In seeds, micro/macro elements were under limit as well as U concentration was also under detection limit. We did not observe any U in the above ground parts (shoots/seeds) of the plant, i.e., under detection limit. Our observation suggests that P. sativum plants may be useful to grow at low radionuclide [U]-contaminated areas for safe human/animal use, but for other fission products, we have to investigate further for the safe human/animal use.

  15. Concentric Ring Method for generating pollen maps. Quercus as case study.

    PubMed

    Oteros, Jose; Valencia, Rosa Mª; Del Río, Sara; Vega, Ana Mª; García-Mozo, Herminia; Galán, Carmen; Gutiérrez, Pablo; Mandrioli, Paolo; Fernández-González, Delia

    2017-01-15

    Mapping pollen concentrations is of great interest to study the health impact and ecological implications or for forestry or agronomical purposes. A deep knowledge about factors affecting airborne pollen is essential for predicting and understanding its dynamics. The present work sought to predict annual Quercus pollen over the Castilla and León region (Central and Northern Spain). Also to understand the relationship between airborne pollen and landscape. Records of Quercus and Quercus pyrenaica pollen types were collected at 13 monitoring sites over a period of 8years. They were analyzed together with land use data applying the Concentric Ring Method (CRM), a technique that we developed to study the relationship between airborne particle concentrations and emission sources in the region. The maximum correlation between the Quercus pollen and forms of vegetation was determined by shrubland and "dehesa" areas. For the specific Qi pyrenaica model (Q. pyrenaica pollen and Q. pyrenaica forest distribution), the maximum influence of emission sources on airborne pollen was observed at 14km from the pollen trap location with some positive correlations up to a distance of 43km. Apart from meteorological behavior, the local features of the region can explain pollen dispersion patterns. The method that we develop here proved to be a powerful tool for multi-source pollen mapping based on land use.

  16. 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.

  17. Spinning-disk generation and drying of monodisperse solid aerosols with output concentrations sufficient for single-breath inhalation studies.

    PubMed

    Byron, P R; Hickey, A J

    1987-01-01

    The air-driven spinning-disk aerosol generator was modified to allow the production of monodisperse dry spherical aerosols of disodium fluorescein (as model solute) in high output concentrations. Output concentrations were determined by filtration. Optical and aerodynamic size distributions were determined microscopically (after electrostatic precipitation) and by cascade impaction. The generator housing allowed the entrainment of 25-microns primary aqueous solution droplets in a 10-L X min-1 downward flow of dry, filtered air. Internal equipment surfaces were machined flush and polished to minimize aerosol losses. Primary droplets were dried within a stainless steel pipe encased in a tube furnace. Water vapor was removed by diffusion drying. Disk-driven air, satellite droplets, and additional dilution air were vented to waste without using a vacuum. Generator yields were increased by reducing the size of the satellite droplet extraction gap. Aerosols were generated reproducibly by delivering aqueous solutions at a rate of 0.2 mL X min-1 to the center of the disk and spinning at 1000 rps. Dry aerosols, with mass median aerodynamic diameters of 2, 4.9, and 9 microns, were produced in concentrations of 0.89, 5.48, and 54.6 micrograms X L-1 from aqueous solutions containing 0.0374, 0.584, and 3.4% solute by weight. Geometric standard deviations were less than 1.2 in all cases. Concentrations are several times higher than others in the literature and are suitable for single-breath inhalation studies of therapeutic aerosol deposition and effect.

  18. Entanglement generation and entanglement concentration of two-photon four-dimensional spatial modes partially entangled Dicke state

    NASA Astrophysics Data System (ADS)

    Shi, Jin

    2017-05-01

    Two-photon four-dimensional spatial modes partially entangled Dicke state can be compactly generated from six concurrent spontaneous parametric down-conversion processes by cascading poling domain structures in 5% MgO-doped poled lithium niobate bulk crystal. Entanglement concentration of the two-photon four-dimensional spatial modes partially entangled Dicke state can be realized by using quantum nondestructive detection of nonlinear Kerr medium, optical beam splitter, and quantum gate operation.

  19. 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.

  20. 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.

  1. Optoacoustic tweezers: a programmable, localized cell concentrator based on opto-thermally generated, acoustically activated, surface bubbles

    PubMed Central

    Zhao, Yanhui; Li, Sixing; Rufo, Joseph; Yang, Shikuan; Guo, Feng; Huang, Tony Jun

    2014-01-01

    We present a programmable, biocompatible technique for dynamically concentrating and patterning particles and cells in a microfluidic device. Since our technique utilizes opto-thermally generated, acoustically activated, surface bubbles, we name it “optoacoustic tweezers.” The optoacoustic tweezers are capable of concentrating particles/cells at any prescribed locations in a microfluidic chamber without the use of permanent structures, rendering it particularly useful for the formation of flexible, complex cell patterns. Additionally, this technique has demonstrated excellent biocompatibility and can be conveniently integrated with other microfluidic units. In our experiments, micro-bubbles were generated by focusing a 405 nm diode laser onto a gold-coated glass chamber. By properly tuning the laser, we demonstrate precise control over the position and size of the generated bubbles. Acoustic waves were then applied to activate the surface bubbles, causing them to oscillate at an optimized frequency. The resulting acoustic radiation force allowed us to locally trap particles/cells, including 15 μm polystyrene beads and HeLa cells, around each bubble. Cell-adhesion tests were also conducted after cell concentrating to confirm the biocompatibility of this technique. PMID:23511348

  2. 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.

  3. Root yield and quality of sugarbeet hybrids with pollinators selected for sodium, potassium, or amino-nitrogen concentration

    USDA-ARS?s Scientific Manuscript database

    Sodium, potassium, and amino-nitrogen, collectively referred to as impurities, are natural constituents of sugarbeet that impede sucrose extraction during factory operations. Lines selected specifically for low or high concentration of a single impurity component were crossed as pollinators with a ...

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

    SciTech Connect

    Wong, Bunsen

    2014-11-01

    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.

  5. P-glycoprotein influences the brain concentrations of cetirizine (Zyrtec), a second-generation non-sedating antihistamine.

    PubMed

    Polli, Joseph W; Baughman, Todd M; Humphreys, Joan E; Jordan, Kelly H; Mote, Angela L; Salisbury, Jo A; Tippin, Timothy K; Serabjit-Singh, Cosette J

    2003-10-01

    Recent in vitro studies have suggested that P-glycoprotein (Pgp) and passive membrane permeability may influence the brain concentrations of non-sedating (second-generation) antihistamines. The purpose of this study was to determine the importance of Pgp-mediated efflux on the in vivo brain distribution of the non-sedating antihistamine cetirizine (Zyrtec), and the structurally related sedating (first-generation) antihistamine hydroxyzine (Atarax). In vitro MDR1-MDCKII monolayer efflux assays demonstrated that cetirizine was a Pgp substrate (B-->A/A-->B + GF120918 ratio = 5.47) with low/moderate passive permeability (PappB-->A = 56.5 nm/s). In vivo, the cetirizine brain-to-free plasma concentration ratios (0.367 to 4.30) were 2.3- to 8.7-fold higher in Pgp-deficient mice compared with wild-type mice. In contrast, hydroxyzine was not a Pgp substrate in vitro (B-->A/A-->B ratio = 0.86), had high passive permeability (PappB-->A + GF120918 = 296 nm/s), and had brain-to-free plasma concentration ratios >73 in both Pgp-deficient and wild-type mice. These studies demonstrate that Pgp-mediated efflux and passive permeability contribute to the low cetirizine brain concentrations in mice and that these properties account for the differences in the sedation side-effect profiles of cetirizine and hydroxyzine.

  6. 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.

  7. Generation and selection of anti-flagellin monoclonal antibodies useful for serotyping Salmonella enterica.

    PubMed

    Hiriart, Yanina; Serradell, Maria; Martínez, Araci; Sampaolesi, Sofia; Maciel, Dolores Gonzalez; Chabalgoity, Jose Alejandro; Yim, Lucía; Algorta, Gabriela; Rumbo, Martin

    2013-01-01

    In developing countries, bacterial acute gastroenteritis continues to be an important cause of morbidity and mortality among young children. Salmonellosis constitutes a major cause of infectious enteritis worldwide, most of them associated to the consumption of contaminated food products. Traditionally, Salmonella has been classified in serovars based on varieties of O and H surface antigens. In the present work we generated and characterized a panel of anti-flagellin monoclonal antibodies (MAbs) in order to select antibodies useful for detecting the H surface antigen. Four different MAbs were obtained by somatic hybridization of splenocytes. We found two MAbs that recognised regions of flagellin conserved among different Salmonella serovars. Other two MAbs recognised structures restricted to Salmonella enterica sv. Typhimurium, being one of them suitable for agglutination tests. Using a diverse panel of S. enterica serovars with different H antigen varieties we confirmed that this MAb agglutinates specifically S. Typhimurium (antigenic formula: 4,12:i:1,2) or other serovars expressing flagellar factor i. In conclusion, we generated a valuable immunochemical tool to be used in simple assays for serotyping of epidemiologically relevant strains. The capacity to characterize specific strains and determine the primary sources of Salmonella contamination generate valuable information of the epidemiology of this microorganism, contributing to the improvement of public health.

  8. 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

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

    PubMed

    Kim, Sun Ja; Chung, T H

    2016-02-03

    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.

  10. 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.

  11. Extraction procedure testing of solid wastes generated at selected metal ore mines and mills

    NASA Astrophysics Data System (ADS)

    Harty, David M.; Terlecky, P. Michael

    1986-09-01

    Solid waste samples from a reconnaissance study conducted at ore mining and milling sites were subjected to the U.S. Environmental Protection Agency extraction procedure (EP) leaching test Sites visited included mines and mills extracting ores of antimony (Sb), mercury (Hg), vanadium (V), tungsten (W), and nickel (Ni). Samples analyzed included mine wastes, treatment pond solids, tailings, low grade ore, and other solid wastes generated at these facilities Analysis of the leachate from these tests indicates that none of the samples generated leachate in which the concentration of any toxic metal parameter exceeded EPA criteria levels for those metals. By volume, tailings generally constitute the largest amount of solid wastes generated, but these data indicate that with proper management and monitoring, current EPA criteria can be met for tailings and for most solid wastes associated with mining and milling of these metal ores. Long-term studies are needed to determine if leachate characteristics change with time and to assist in development of closure plans and post closure monitoring programs.

  12. Engineering and Design: Selecting Reaction-Type Hydraulic Turbines and Pump Turbines and Hydroelectric Generators and Generator-Motors

    DTIC Science & Technology

    2007-11-02

    turbines must k designed to suit the specific range of conditions under which they will operate, each generator and generator- motor is unique in that the... conditions . Continuous, heavy-duty amortisseur windings me required for generator-rotors which are to be started as induction motors . (2) ~rtisseur...cubic feet, and the available water horsepwer is: WHP = wQH 550 d. The amount of power that can be prducd under pradical working conditions is less

  13. Changes in phenolic concentrations during recurrent selection for resistance to the Mediterranean corn borer (Sesamia nonagrioides Lef.).

    PubMed

    Santiago, Rogelio; Sandoya, German; Butrón, Ana; Barros, Jaime; Malvar, Rosa A

    2008-09-10

    Recurrent selection has been reported as successful for improving maize resistance against corn borers. This study was conducted to determine if phenolics concentration in maize changes during recurrent selection to improve stalk resistance to the Mediterranean corn borer. Three cycles of selection [EPS12(S)C0, ESP12(S)C2, and EPS12(S)C3] from the maize synthetic population EPS12 and test crosses to inbred lines A639, B93, and EP42 were field grown and artificially infested with Mediterranean corn borer larvae, and the pith tissues were sampled for biochemical analyses. Two major simple phenolic acids [p-coumaric (p-CA) and trans-ferulic (E-FA) acids] were identified in free and cell-wall fractions, whereas four isomers of diferulic acid (DFA) (8-5'l, 5-5', 8-o-4', and 8-5' benzofuran form) were present in the cell-wall bound fraction. The selection cycles EPS12(S)C0 and EPS12(S)C3 showed less damage and higher cell wall phenolics concentrations than the cycle EPS12(S)C2. In addition, higher concentrations of total DFAs were associated with shorter tunnel length and lower numbers of larvae per stem. The current study shows new and concrete evidence that the cell-wall bound phenolics could have a determinative role in the resistance to the Mediterranean corn borer, although future development of recurrent and divergent selection cycles will clarify this point.

  14. BRBN-T validation: adaptation of the Selective Reminding Test and Word List Generation.

    PubMed

    Neves, Mariana Rigueiro; Passos, Ana Margarida; Ferreira, Aristides; Sousa, Cláudia; Sá, Andreia; Sá, Maria José

    2015-10-01

    Objective This study aims to present the Selective Reminding Test(SRT) and Word List Generation (WLG) adaptation to the Portuguese population, within the validation of the Brief Repeatable Battery of Neuropsychological Tests (BRBN-T)for multiple sclerosis (MS) patients.Method 66 healthy participants (54.5% female) recruited from the community volunteered to participate in this study.Results A combination of procedures from Classical Test Theory (CTT) and Item Response Theory (ITR) were applied to item analysis and selection. For each SRT list, 12 words were selected and 3 letters were chosen for WLG to constitute the final versions of these tests for the Portuguese population.Conclusion The combination of CTT and ITR maximized the decision making process in the adaptation of the SRT and WLG to a different culture and language (Portuguese). The relevance of this study lies on the production of reliable standardized neuropsychological tests, so that they can be used to facilitate a more rigorous monitoring of the evolution of MS, as well as any therapeutic effects and cognitive rehabilitation.

  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.

  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. Dynamic analysis of concentrated solar supercritical CO2-based power generation closed-loop cycle

    DOE PAGES

    Osorio, Julian D.; Hovsapian, Rob; Ordonez, Juan C.

    2016-01-01

    Here, the dynamic behavior of a concentrated solar power (CSP) supercritical CO2 cycle is studied under different seasonal conditions. The system analyzed is composed of a central receiver, hot and cold thermal energy storage units, a heat exchanger, a recuperator, and multi-stage compression-expansion subsystems with intercoolers and reheaters between compressors and turbines respectively. Energy models for each component of the system are developed in order to optimize operating and design parameters such as mass flow rate, intermediate pressures and the effective area of the recuperator to lead to maximum efficiency. Our results show that the parametric optimization leads the systemmore » to a process efficiency of about 21 % and a maximum power output close to 1.5 MW. The thermal energy storage allows the system to operate for several hours after sunset. This operating time is approximately increased from 220 to 480 minutes after optimization. The hot and cold thermal energy storage also lessens the temperature fluctuations by providing smooth changes of temperatures at the turbines and compressors inlets. Our results indicate that concentrated solar systems using supercritical CO2 could be a viable alternative to satisfying energy needs in desert areas with scarce water and fossil fuel resources.« less

  18. Dynamic analysis of concentrated solar supercritical CO2-based power generation closed-loop cycle

    SciTech Connect

    Osorio, Julian D.; Hovsapian, Rob; Ordonez, Juan C.

    2016-01-01

    Here, the dynamic behavior of a concentrated solar power (CSP) supercritical CO2 cycle is studied under different seasonal conditions. The system analyzed is composed of a central receiver, hot and cold thermal energy storage units, a heat exchanger, a recuperator, and multi-stage compression-expansion subsystems with intercoolers and reheaters between compressors and turbines respectively. Energy models for each component of the system are developed in order to optimize operating and design parameters such as mass flow rate, intermediate pressures and the effective area of the recuperator to lead to maximum efficiency. Our results show that the parametric optimization leads the system to a process efficiency of about 21 % and a maximum power output close to 1.5 MW. The thermal energy storage allows the system to operate for several hours after sunset. This operating time is approximately increased from 220 to 480 minutes after optimization. The hot and cold thermal energy storage also lessens the temperature fluctuations by providing smooth changes of temperatures at the turbines and compressors inlets. Our results indicate that concentrated solar systems using supercritical CO2 could be a viable alternative to satisfying energy needs in desert areas with scarce water and fossil fuel resources.

  19. Determination of glucose concentration in a scattering medium based on selected wavelengths by use of an overtone absorption band.

    PubMed

    Yoon, Gilwon; Amerov, Airat K; Jeon, Kye Jin; Kim, Yoen-Joo

    2002-03-01

    A method and device for measuring glucose concentration in a scattering medium have been developed. A spectral range of 800-1800 nm is considered for wavelength selection because of its deeper penetration into biological tissue and the presence of a glucose absorption band. An algorithm based on selected wavelengths is proposed to minimize interference from other components. The optimal distance between the light source and the detector for diffuse reflectance measurement minimizes the influence of medium scattering. The proposed algorithm and measuring device are tested with a solution containing milk with added glucose. Glucose concentrations between 0 and 2000 mg/dl are determined with a correlation coefficient of 0.977. We also investigate the influence of concentration variations of other substances such as water, hemoglobin, albumin, and cholesterol when they are mixed in a scattering medium.

  20. 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.

  1. Sub-wavelength energy concentration with electrically generated mid-infrared surface plasmons.

    PubMed

    Bousseksou, A; Babuty, A; Tetienne, J-P; Moldovan-Doyen, I; Braive, R; Beaudoin, G; Sagnes, I; De Wilde, Y; Colombelli, R

    2012-06-18

    While freely propagating photons cannot be focused below their diffraction limit, surface-plasmon polaritons follow the metallic surface to which they are bound, and can lead to extremely sub-wavelength energy volumes. These properties are lost at long mid-infrared and THz wavelengths where metals behave as quasi-perfect conductors, but can in principle be recovered by artificially tailoring the surface-plasmon dispersion. We demonstrate - in the important mid-infrared range of the electromagnetic spectrum - the generation onto a semiconductor chip of plasmonic excitations which can travel along long distances, on bent paths, to be finally focused into a sub-wavelength volume. The demonstration of these advanced functionalities is supported by full near-field characterizations of the electromagnetic field distribution on the surface of the active plasmonic device.

  2. 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.

  3. Osmotic and diffusio-osmotic flow generation at high solute concentration. II. Molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Yoshida, Hiroaki; Marbach, Sophie; Bocquet, Lydéric

    2017-05-01

    In this paper, we explore osmotic transport by means of molecular dynamics (MD) simulations. We first consider osmosis through a membrane and investigate the reflection coefficient of an imperfectly semi-permeable membrane, in the dilute and high concentration regimes. We then explore the diffusio-osmotic flow of a solute-solvent fluid adjacent to a solid surface, driven by a chemical potential gradient parallel to the surface. We propose a novel non-equilibrium MD (NEMD) methodology to simulate diffusio-osmosis, by imposing an external force on every particle, which properly mimics the chemical potential gradient on the solute in spite of the periodic boundary conditions. This NEMD method is validated theoretically on the basis of linear-response theory by matching the mobility with their Green-Kubo expressions. Finally, we apply the framework to more realistic systems, namely, a water-ethanol mixture in contact with a silica or a graphene surface.

  4. Folate concentrations during pregnancy and autistic traits in the offspring. The Generation R Study.

    PubMed

    Steenweg-de Graaff, Jolien; Ghassabian, Akhgar; Jaddoe, Vincent W V; Tiemeier, Henning; Roza, Sabine J

    2015-06-01

    In a population-based study, we examined the associations of maternal plasma folate concentrations at 13 weeks of gestation and prenatal folic acid supplement use with autistic traits in the offspring at the age of six years. Parent-reported autistic traits were assessed using the Social Responsiveness Scale short form. Maternal folate was not associated with autistic traits in the offspring. In contrast, prenatal folic acid use was associated with less child autistic traits. Future research should focus on the timing of the potential effect of prenatal folate on the development of autistic traits in combination with clinical diagnosis of autism in the offspring. © The Author 2014. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  5. A survey of selected heavy metal concentrations in Wisconsin dairy feeds.

    PubMed

    Li, Y; McCrory, D F; Powell, J M; Saam, H; Jackson-Smith, D

    2005-08-01

    Heavy metals such as zinc (Zn), copper (Cu), chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) are potential bioaccumulative toxins of the dairy production system. The heavy metal content of dairy feeds, however, remains poorly documented, particularly in the United States. This survey determined the heavy metal content of 203 typical dairy ration components sampled from 54 dairy farms in Wisconsin. Lowest heavy metal concentrations were found in homegrown alfalfa (Medicago sativa L.) hay and haylage, and corn (Zea mays L.) grain and silage. Highest metal concentrations were found in purchased feeds, particularly mineral supplements, and to a lesser extent corn- or soybean-based concentrates. Zinc and Cu were found at the highest concentration in complete dairy (total mixed and aggregated component) rations and reflected the deliberate addition of these metals to meet animal nutrient requirements although more than half the farms fed Cu and Zn above US recommended levels. Concentrations of Cr, As, Cd, and Pb were present in much lower concentrations and decreased in the order Cr > As > Pb > Cd. No complete Wisconsin dairy ration contained heavy metal concentrations above US maximum acceptable concentrations and would be unlikely to induce any toxic effects in dairy cattle. Concentrations of Cd in complete dairy rations were closest to US maximum acceptable concentrations, suggesting the greatest potential long-term risk to exceed US maximum acceptable concentrations if whole farm levels of Cd were to increase in the future. With the exception of Pb, the main sources of Zn, Cu, Cr, As, and Cd in the complete dairy feed ration originated from imported feed. The continued importation of heavy metals in dairy feed is likely to be associated with accumulation of these metals in soils where manure is applied. Although the cycling of many heavy metals through the dairy food chain will be limited by factors such as a soil's cation exchange capacity, pH, salinity

  6. Calculating fluoride concentrations data using ambient temperatures in drinking water distribution networks in select provinces of Iran.

    PubMed

    Zazouli, Mohammad Ali; Sadeghnezhad, Reza; Kalankesh, Laleh R

    2017-12-01

    Fluoride concentrations in drinking water were analyzed relative to air temperature data collected in different provinces of Iran. Determining suitable concentrations of fluoride in drinking water is crucial for communities because of the health effects of fluoride on humans. This study analyzed fluoride concentrations in drinking water from selected Iranian provinces. The data were derived mainly from a detailed literature review. The annual mean maximum temperatures (AMMTs) were collected from a popular website that maintains records of daily ambient temperature measurements for the last five years (2012-2016). Using regional ambient temperatures, the optimal value of fluoride in drinking water for each province was calculated by the Galgan and Vermillion formula. These optimal fluoride concentrations in drinking water for different Iranian regions were calculated to be 0.64-1.04 mg F/L. Most of the selected provinces were found to have acceptable concentrations of fluoride, except for Alborz, Khuzestan, and Hormozgan, which reported concentrations of 0.66, 0.66, and 0.64 mg/L, respectively.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    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 in the mock catalogues. We then modelled 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 data sets 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 per cent completeness and purity down to 8 × 1013 h-1 M⊙ up to z < 1. At higher redshifts, the same completeness and purity are obtained with the larger mass threshold of 2 × 1014 h-1 M⊙ up to z = 2. The Euclid-Pessimistic selection function has a similar shape with ˜10 per cent higher mass limit. LSST shows ˜5 per cent higher mass limit than Euclid-Optimistic up to z < 0.7 and increases afterwards, reaching a value of 2 × 1014 h-1 M⊙ at z = 1.4. Similar selection functions with only 80 per cent completeness threshold have also been computed. The complementarity of these results with selection functions for surveys in other bands is discussed.

  8. Concentration of glycerol in aqueous microdroplets by selective removal of water.

    PubMed

    Bajpayee, Anurag; Edd, Jon F; Chang, Anthony; Toner, Mehmet

    2010-02-15

    A major roadblock to the vitrification of cells is the requirement of high concentrations of cryoprotectant (CPA) chemicals and the damage caused by prolonged exposure of cells to these high concentrations above the glass transition temperature. These effects are minimized with controlled CPA loading. Certain organic oils, such as soybean oil, are made of triacylglycerols and are capable of dissolving small amounts of water, a property which is enhanced significantly as temperature is increased. This phenomenon was exploited here to accomplish temperature-controlled concentration of glycerol in single water droplets dispersed in the organic phase. Emulsions of aqueous solutions of glycerol in soybean oil were made and subjected to a temperature increase of 10 degrees C from room temperature. Upon increasing temperature, water dissolved into the oil, rendering the 15-20 microm droplets concentrated an average of 3.6 times and 2.6 times for 1 and 2 M starting concentrations, respectively, with the oil-insoluble glycerol in 90-110 s. This phenomenon could be used to dynamically concentrate CPAs within cell-containing droplets which may then be vitrified before being exposed to high temperatures for fatally long times.

  9. Concentration of Glycerol in Aqueous Microdroplets by Selective Removal of Water

    PubMed Central

    Bajpayee, Anurag; Edd, Jon F.; Chang, Anthony; Toner, Mehmet

    2010-01-01

    Among the challenges associated with vitrification of cells, a major roadblock is the requirement of high concentrations of cryoprotectant (CPA) chemicals and the damages caused by prolonged exposure of cells to these high concentrations above the glass transition temperature. These effects are minimized with controlled CPA loading. Certain organic oils, such as soybean oil, are made of triacylglycerols and are capable of dissolving small amounts of water, a property which enhances significantly with temperature. This phenomenon was exploited here to accomplish temperature controlled concentration of glycerol in single water droplets dispersed in the organic phase. Emulsions of aqueous solutions of glycerol in soybean oil were made and subjected to temperature increase of 10 °C from room temperature. Upon increasing temperature, water dissolved into the oil rendering the 15–20 micron droplets concentrated an average of 3.6 times and 2.6 times for 1M and 2M starting concentrations respectively with the oil-insoluble glycerol in 90 – 110 seconds. This phenomenon could be used to dynamically concentrate CPAs within cell-containing droplets which may then be vitrified before being exposed to high temperatures for fatally long times. PMID:20102162

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. In vivo effects of zinc deficiency on calmodulin concentrations in selected rat tissues

    SciTech Connect

    Law, J.S.; McBride, S.A.; Graham, S.; Nelson, N.R.; Slotnick, B.M.; Henkin, R.I.

    1987-12-14

    Two groups of male Sprague-Dawley rats, one fed zinc-deficient diet, ad libitum, the other, pair-fed with the same diet, but given supplemental zinc in the drinking water were studied. After ten weeks of diet, rats were exsanguinated and zinc and calmodulin concentration in brain and testes were measured. Mean zinc concentration in testes was significantly decreased in rats fed zinc-deficient diet without supplemental Zn/sup + +/, but mean zinc concentration in brain was not different. Similarly, mean calmodulin concentration in testes was decreased in rats fed zinc-deficient diet without supplemental Zn/sup + +/ whereas mean calmodulin concentration in brain was not different. Distribution studies of zinc and calmodulin showed that both zinc and calmodulin were released more freely into soluble fractions of testes in rats fed zinc-deficient diet without supplemental Zn/sup + +/. These results indicate, for the first time in in vivo studies, that zinc influences the calmodulin content of testes. 26 references, 2 figures, 4 tables.

  19. Field trials for corrosion inhibitor selection and optimization, using a new generation of electrical resistance probes

    SciTech Connect

    Ridd, B.; Blakset, T.J.; Queen, D.

    1998-12-31

    Even with today`s availability of corrosion resistant alloys, carbon steels protected by corrosion inhibitors still dominate the material selection for pipework in the oil and gas production. Even though laboratory screening tests of corrosion inhibitor performance provides valuable data, the real performance of the chemical can only be studied through field trials which provide the ultimate test to evaluate the effectiveness of an inhibitor under actual operating conditions. A new generation of electrical resistance probe has been developed, allowing highly sensitive and immediate response to changes in corrosion rates on the internal environment of production pipework. Because of the high sensitivity, the probe responds to small changes in the corrosion rate, and it provides the corrosion engineer with a highly effective method of optimizing the use of inhibitor chemicals resulting in confidence in corrosion control and minimizing detrimental environmental effects.

  20. Polarization selective computer-generated holograms realized in glass by femtosecond laser induced nanogratings.

    PubMed

    Cai, Wenjian; Libertun, Ariel R; Piestun, Rafael

    2006-05-01

    We demonstrate polarization selective computer-generated holograms (PSCGH) for visible light operation fabricated in glass by a femtosecond laser. For this purpose we create arrays of tailored microwaveplates by controlling the laser formation of nanogratings embedded in fused silica. A birefringent cell-oriented encoding method adapted to the characteristics of the physical writing process is proposed and implemented. According to this method, each cell contains a micro-waveplate with controlled phase retardation and orientation. A detour of each microwaveplate, combined with the orientation of its principal optical axis, simultaneously realizes a different phase function for each polarization. PSCGH's are attractive for integration with other free-space and guided-wave devices embedded in glass.

  1. 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

  2. Explicit category learning in Parkinson's disease: deficits related to impaired rule generation and selection processes.

    PubMed

    Price, Amanda L

    2006-03-01

    The present study examined the source of explicit category learning deficits previously noted in patients with Parkinson's disease (PD). Task stimuli consisted of 4 binary-valued cues that together determined category assignment, although some cues were more important for the categorization decision. Participants verbalized the hypotheses being tested to provide several measures of the hypothesis testing. Analyses of these verbal protocols indicated that PD patients were impaired on rule generation and selection but not rule shifting. Patients had particular difficulty noting the relative importance of the cues. Specific aspects of performance were differently correlated with neuropsychological measures of working memory and hypothesis testing ability. Together, the results suggest that the cognitive processes required for explicit category learning are mediated by partially distinct neural mechanisms.

  3. 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

  4. Simultaneous optimization of variables influencing selectivity and elution strength in micellar liquid chromatography. Effect of organic modifier and micelle concentration.

    PubMed

    Strasters, J K; Breyer, E D; Rodgers, A H; Khaledi, M G

    1990-07-06

    Previously, the simultaneous enhancement of separation selectivity with elution strength was reported in micellar liquid chromatography (MLC) using the hybrid eluents of water-organic solvent-micelles. The practical implication of this phenomenon is that better separations can be achieved in shorter analysis times by using the hybrid eluents. Since both micelle concentration and volume fraction of organic modifier influence selectivity and solvent strength, only an investigation of the effects of a simultaneous variation of these parameters will disclose the full separation capability of the method, i.e. the commonly used sequential solvent optimization approach of adjusting the solvent strength first and then improving selectivity in reversed-phase liquid chromatography is inefficient for the case of MLC with the hybrid eluents. This is illustrated in this paper with two examples: the optimization of the selectivity in the separation of a mixture of phenols and the optimization of a resolution-based criterion determined for the separation of a number of amino acids and small peptides. The large number of variables involved in the separation process in MLC necessitates a structured approach in the development of practical applications of this technique. A regular change in retention behavior is observed with the variation of the surfactant concentration and the concentration of organic modifier, which enables a successful prediction of retention times. Consequently interpretive optimization strategies such as the interative regression method are applicable.

  5. Effects of selection for blood serum IGF-I concentration on reproductive performance of female Angus beef cattle.

    PubMed

    Zhang, X; Davis, M E; Moeller, S J; Ottobre, J S

    2013-09-01

    Reproductive performance of animals affects lifetime productivity. However, improvement of reproductive traits via direct selection is generally slow due to low heritability. Therefore, identification of indicator traits for reproductive performance may enhance genetic response. Previous studies showed that serum IGF-I concentration is a candidate indicator for growth and reproductive traits. The objective of our study was to estimate the variances or covariances of IGF-I concentration with reproductive traits. Data were collected from a divergent selection experiment for serum IGF-I concentration at the Eastern Agricultural Research Station owned by The Ohio State University. The study included a total of 2,662 calves in the 1989 to 2005 calf crops. Variance or covariance components were estimated for direct and maternal genetic effects, maternal environment effects, environment effects, and phenotypic effects using an animal model in a multiple-trait, derivative-free, restricted maximum likelihood (MTDFREML, Boldman et al., 1995) computer program. Direct additive genetic correlations suggest that selection for greater IGF-I concentration (heritability = 0.50 ± 0.07) could lead to increased conception rate (heritability = 0.11 ± 0.06, r = 0.32, P < 0.001) and calving rate (heritability = 0.13 ± 0.06, r = 0.43, P < 0.001) and decreased age at first calving in heifers (heritability = 0.35 ± 0.20, r = -0.40, P < 0.001).

  6. 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.

  7. Genetic control of the environmental variance for birth weight in seven generations of a divergent selection experiment in mice.

    PubMed

    Formoso-Rafferty, N; Cervantes, I; Ibáñez-Escriche, N; Gutiérrez, J P

    2016-06-01

    Data from seven generations of a divergent selection experiment designed for environmental variability of birth weight were analysed to estimate genetic parameters and to explore signs of selection response. A total of 10 783 birth weight records from 638 females and 1127 litters in combination with 10 007 pedigree records were used. Each record of birth weight was assigned to the mother of the pup in a heteroscedastic model, and after seven generations of selection, evidence of success in the selection process was shown. A Bayesian analysis showed that success of the selection process started from the first generation for birth weight and from the second generation for its environmental variability. Genetic parameters were estimated across generations. However, only from the third generation onwards were the records useful to consider the results to be reliable. The results showed a consistent positive and low genetic correlation between the birth weight trait and its environmental variability, which could allow an independent selection process. This study has demonstrated that the genetic control of the birth weight environmental variability is possible in mice. Nevertheless, before the results are applied directly in farm animals, it would be worth confirming any other implications on other important traits, such as robustness, longevity and welfare.

  8. 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.

  9. Silver concentrations and selected hydrologic data in the Upper Colorado River basin, 1991-92

    USGS Publications Warehouse

    Johncox, D.A.

    1993-01-01

    The U.S. Geological Survey, in cooperation with the Colorado River Water Conservation District and the Northern Colorado Water Conservancy District, collected water and sediment samples in May and September 1991 and 1992 from nine stream-sampling sites and three lake-sampling sites within the Upper Colorado River Basin upstream from Kremmling, Colorado. Data were collected to determine the present (1992) conditions of the Upper Colorado River Basin regarding silver concentrations in the water and sediment. Lake-water and stream-water samples were analyzed for concentrations of total recoverable silver, dissolved silver, and suspended solids. Lake- and stream-bottom material was analyzed for concentrations of total recoverable silver. Additional data collected were streamflow, specific conductance, pH, and water temperature. Transparency (Secchi-disk measurements) also was measured in the lakes.

  10. Patient selection for upper airway stimulation: is concentric collapse in sleep endoscopy predictable?

    PubMed

    Steffen, Armin; Frenzel, Henning; Wollenberg, Barbara; König, Inke R

    2015-12-01

    Upper airway stimulation is an effective treatment option for obstructive sleep apnea after failure of positive airway pressure (PAP) therapy. To ensure a therapeutic effect, closed-loop hypoglossal nerve implants require the absence of palatal complete concentric collapse during sleep endoscopy. The frequency and potential predictors of this exclusion criterion are unknown. Over a 2-year period, 74 consecutive patients with sleep apnea who sought PAP alternatives were evaluated with sleep endoscopy using propofol. The influence of sleep apnea severity and anthropometric characteristics as predictors of sleep endoscopy results was investigated. One-fifth of all patients showed a concentric collapse. Gender and age did not predict the presence of concentric collapse, but higher body mass and apnea hypopnea index values were predictive (p = 0.011; e.g., 0.026). The most commonly used body mass index values for upper airway stimulation indications demonstrated acceptable specificity (BMI 32 kg/m(2) 0.71, 95 % confidence interval = 0.57, 0.82; e.g., 35 kg/m(2) 0.81, 95 % confidence interval = 0.69, 0.90). Despite the association with overweight, a significant number of severely overweight patients had no concentric palatal collapse. Concentric collapse is a somewhat common condition encountered in sleep endoscopy evaluations of PAP alternatives, and cannot be sustainably predicted with anthropometric or sleep assessments. Sleep surgeons should be aware of the possibility of concentric collapse, especially in candidates who are more overweight and have severe sleep apnea. Sleep endoscopy can be useful for providing information about continuous positive airway pressure (CPAP) alternatives or to motivate patient adherence to treatment.

  11. The prediction of aquatic sediment-associated trace element concentration using selected geochemical factors

    USGS Publications Warehouse

    Horowitz, A.J.; Elrick, K.A.; Hooper, R.P.

    1989-01-01

    Multiple linear regression models calculated from readily obtainable chemical and physical parameters can explain a high percentage (70 per cent or greater) of observed sediment-trace element variance for Cu, Zn, Pb, Cr, Ni, Co, As, Sb, Se, and Hg in a widely divergent suite of 60 sediment samples. The geochemical parameters included in the models were of physical (e.g. grain size, surface area) and a chemical (e.g. organic matter, amorphous iron oxides) nature. Comparison between actual and predicted trace element concentrations obtained from the models may provide a means of defining "average' sediment trace element concentrations. -from Authors

  12. K-Ras(G12D)-selective inhibitory peptides generated by random peptide T7 phage display technology.

    PubMed

    Sakamoto, Kotaro; Kamada, Yusuke; Sameshima, Tomoya; Yaguchi, Masahiro; Niida, Ayumu; Sasaki, Shigekazu; Miwa, Masanori; Ohkubo, Shoichi; Sakamoto, Jun-Ichi; Kamaura, Masahiro; Cho, Nobuo; Tani, Akiyoshi

    2017-03-11

    Amino-acid mutations of Gly(12) (e.g. G12D, G12V, G12C) of V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (K-Ras), the most promising drug target in cancer therapy, are major growth drivers in various cancers. Although over 30 years have passed since the discovery of these mutations in most cancer patients, effective mutated K-Ras inhibitors have not been marketed. Here, we report novel and selective inhibitory peptides to K-Ras(G12D). We screened random peptide libraries displayed on T7 phage against purified recombinant K-Ras(G12D), with thorough subtraction of phages bound to wild-type K-Ras, and obtained KRpep-2 (Ac-RRCPLYISYDPVCRR-NH2) as a consensus sequence. KRpep-2 showed more than 10-fold binding- and inhibition-selectivity to K-Ras(G12D), both in SPR analysis and GDP/GTP exchange enzyme assay. KD and IC50 values were 51 and 8.9 nM, respectively. After subsequent sequence optimization, we successfully generated KRpep-2d (Ac-RRRRCPLYISYDPVCRRRR-NH2) that inhibited enzyme activity of K-Ras(G12D) with IC50 = 1.6 nM and significantly suppressed ERK-phosphorylation, downstream of K-Ras(G12D), along with A427 cancer cell proliferation at 30 μM peptide concentration. To our knowledge, this is the first report of a K-Ras(G12D)-selective inhibitor, contributing to the development and study of K-Ras(G12D)-targeting drugs.

  13. Generating/Analyzing Alternative Strategies and Selecting Strategies. Systematic Planning Series for Local Education Agencies. Monograph Number 5.

    ERIC Educational Resources Information Center

    Boone, Lee; And Others

    Once planners at the local level have specified the educational objectives of their program, they should determine how those objectives can be reached. The possibility of selecting an adequate strategy is improved if several alternative strategies are generated and analyzed before a decision is made. Suggestions for generating alternative…

  14. 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…

  15. 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)

  16. [Third generation selective estrogen receptor modulators: benefits beyond bone. II, endometrial action].

    PubMed

    Calaf Alsina, Joaquín; Coronado Martín, Pluvio J

    2013-03-16

    The selective estrogen receptor modulators (SERMs) are substances with estrogenic/anti-estrogen effect that act differently depending on the tissue and composition. Since the discovery that tamoxifen and raloxifene (RLX) had a breast cancer preventive effect, the search for the perfect SERM has been the goal. The evidence that tamoxifen significantly increased the risk of endometrial cancer as compared to placebo made this tissue the center of interest in developing new SERMs. Thus, ospemifen, arzoxifene, lasofoxifene (LFX) and bazedoxifene (BZA) appeared as third-generation SERMs but only BZA reached the stage of clinical use. Both experimental and clinical data available on the effects of RLX or third-generation SERMs reaching clinical stage (LFX and BZA) show either neutrality or anti-estrogenic effects at endometrial level. BZA has shown to be equivalent to vehicle in several experimental conditions and acts as anti-estrogen in models were estrogens (conjugated equine estrogens [CEE] or E2) were co-administered. In a 7 years pivotal study the incidence of endometrial adenocarcinoma has been significantly lower in the BZA than in the placebo group. Moreover, in a clinical trial to evaluate the ability of a combination of BZA and CEE to prevent hot flushes in symptomatic postmenopausal women, doses of 20mg or higher of BZA have significantly decreased the risk of presenting endometrial hyperplasia when co-administered with either 0.650 or 0.450mg of CEE. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  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. 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.

  19. Gold nanocage assemblies for selective second harmonic generation imaging of cancer cell.

    PubMed

    Demeritte, Teresa; Fan, Zhen; Sinha, Sudarson Sekhar; Duan, Jinsong; Pachter, Ruth; Ray, Paresh C

    2014-01-20

    Second harmonic generation (SHG) imaging using near infrared laser light is the key to improving penetration depths, leading to biological understanding. Unfortunately, currently SHG imaging techniques have limited capability due to the poor signal-to-noise ratio, resulting from the low SHG efficiency of available dyes. Targeted tumor imaging over nontargeted tissues is also a challenge that needs to be overcome. Driven by this need, in this study, the development of two-photon SHG imaging of live cancer cell lines selectively by enhancement of the nonlinear optical response of gold nanocage assemblies is reported. Experimental results show that two-photon scattering intensity can be increased by few orders of magnitude by just developing nanoparticle self-assembly. Theoretical modeling indicates that the field enhancement values for the nanocage assemblies can explain, in part, the enhanced nonlinear optical properties. Our experimental data also show that A9 RNA aptamer conjugated gold nanocage assemblies can be used for targeted SHG imaging of the LNCaP prostate cancer cell line. Experimental results with the HaCaT normal skin cell lines show that bioconjugated nanocage-based assemblies demonstrate SHG imaging that is highly selective and will be able to distinguish targeted cancer cell lines from other nontargeted cell types. After optimization, this reported SHG imaging assay could have considerable application for biology. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. [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.

  1. Manipulating the selection forces during affinity maturation to generate cross-reactive HIV antibodies

    PubMed Central

    Wang, Shenshen; Mata-Fink, Jordi; Kriegsman, Barry; Hanson, Melissa; Irvine, Darrell J.; Eisen, Herman N.; Burton, Dennis R.; Wittrup, K. Dane; Kardar, Mehran; Chakraborty, Arup K.

    2015-01-01

    Summary Generation of potent antibodies by a mutation-selection process called affinity maturation is a key component of effective immune responses. Antibodies that protect against highly mutable pathogens must neutralize diverse strains. Developing effective immunization strategies to drive their evolution requires understanding how affinity maturation happens in an enviroment where variants of the same antigen are present. We present an in silico model of affinity maturation driven by antigen variants which reveals that induction of cross-reactive antibodies often occurs with low probability because conflicting selection forces, imposed by different antigen variants, can frustrate affinity maturation. We describe how variables such as temporal pattern of antigen administration influence the outcome of this frustrated evolutionary process. Our calculations predict, and experiments in mice with variant gp120 constructs of the HIV envelope protein confirm, that sequential immunization with antigen variants is preferred over a cocktail for induction of cross-reactive antibodies focused on the shared CD4 binding site epitope. PMID:25662010

  2. 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.

  3. 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

  4. Activity concentration measurements of selected radionuclides in seals from Canadian Arctic.

    PubMed

    Chen, Jing; Zhang, Weihua; Sadi, Baki; Wang, Xiaowa; Muir, Derek C G

    2017-04-01

    The activity concentrations of naturally occurring radionuclides (such as (226)Ra, (210)Pb and (210)Po) and long lived (137)Cs were measured in a total of 119 tissue samples (43 blubber, 43 liver, and 33 muscle samples) from 40 ringed seals and 4 bearded seals collected in the Arviat area of Canada during the fall of 2014. Activity concentration of (210)Po was measured in all seal liver and muscle samples individually. The average (210)Po activity concentrations were 25 ± 7.6 Bq/kg fresh weight (fw) in muscle and 211 ± 58 Bq/kg fw in liver for ringed seals, and 20 ± 6.1 Bq/kg fw in muscle and 231 ± 150 Bq/kg fw in liver for bearded seals. Due to insufficient sample material for most samples collected, gamma counting for radioactive caesium and radiochemical analysis for (226)Ra and (210)Pb were performed for pooled samples. Activity concentrations of (210)Pb and (226)Ra were generally below detection limits. While (134)Cs activity concentration was not detectable, (137)Cs activity concentration was detected in muscle and liver samples. On average, the (137)Cs activity concentrations were 0.25 ± 0.05 and 0.12 ± 0.04 Bq/kg fw in muscle and liver samples of ringed seals, and 0.11 ± 0.02 and 0.10 ± 0.03 Bq/kg fw in muscle and liver samples of bearded seals, respectively. Neither (210)Po nor (137)Cs were detected in the blubber samples. This study confirmed that (210)Po is the dominant contributor to radiation doses resulting from seal consumption. Man-made contaminant (137)Cs only contributes less than 0.01% of the total ingestion dose obtained from Arviat seals. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. Determination of arsenic in chicken feed by hydride generation atomic absorption spectrometry after pre-concentration with polyurethane foam.

    PubMed

    Dos Passos, A S; Néri, T S; Maciel, M V; da Silva Romão, I L; Lemos, V A

    2012-01-01

    A pre-concentration procedure with solid-phase extraction was developed for the determination of arsenic (As) in chicken feed using hydride generation atomic absorption spectrometry (HG-AAS). The procedure was based on the sorption of As(III) ions as complexes with ammonium pyrrolidine dithiocarbamate onto a mini-column packed with polyurethane foam. After pre-concentration, the As was removed from the mini-column by acid solution, and the analyte content in the eluate was measured by HG-AAS. The following main experimental conditions were established: adjustment of the As solution pH with 0.05 mol l⁻¹ HCl, 2.88 × 10⁻³ mol l⁻¹ complexing agent concentration and 6.0 mol l⁻¹ eluting hydrochloric acid concentration. The proposed method produced an enrichment factor of 67, with 0.050 and 0.165 µg g⁻¹ limits of detection and quantification, respectively. The procedure was applied to the determination of As content in two types of chicken feed using the proposed procedure and atomic absorption spectrometry with electrothermal atomisation (ETAAS). The t-test indicated that the results were not significantly different at a confidence level of 95%.

  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. 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.

  12. 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.

  13. 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.

  14. Effect of hydrofluoric acid concentration and etching duration on select surface roughness parameters for zirconia.

    PubMed

    Smielak, Beata; Klimek, Leszek

    2015-06-01

    The surface of zirconia is resistant to chemical treatment. Roughening the surface of densely sintered zirconia still poses a challenge in dentistry. The purpose of the study was to examine the effects of hydrofluoric acid on the quality of surface roughening of zirconia. One hundred cylindrical disks made from zirconia (Ceramill Zi; Amann Girrbach AG) were divided into 4 groups. Three groups (n=30) were distinguished on the basis of hydrofluoric acid (HF) concentration: 40% HF, 9.5% HF, and 5% HF. The groups were then further divided into 3 groups of 10 specimens, each based on etch time (1, 5, or 15 minutes). The control group (n=10) consisted of specimens polished with SiC abrasive paper. The surface was examined with scanning electron microscopy, and the roughness was measured with a profilometer and confocal laser scanning microscope. The mean arithmetic profile deviation (Ra(mean)) and mean maximum height of profile (Rz(mean)) results for the etched surfaces in relationship to the baseline surfaces were compared with the Student t test for averaged data (α=.05). When etched with 40% HF concentration, the Ra(mean) and Rz(mean) results were statistically higher (P<.01) for the etched surfaces than for the baseline surfaces. When etched with 9.5% HF concentration, the higher Ra(mean) and Rz(mean) results were only statistically significant (P<.01) after 15 minutes. Etching with 5% HF concentration showed no significant differences (P>.05). Etching with a 5% HF solution should not be recommended as a method for roughening zirconia surfaces. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  15. Effect of long-term vigabatrin therapy on selected neurotransmitter concentrations in cerebrospinal fluid.

    PubMed

    Ben-Menachem, E; Persson, L I; Mumford, J; Haegele, K D; Huebert, N

    1991-01-01

    Ten patients, suffering from drug-resistant complex partial seizures were treated for a period of up to 3 years with vigabatrin (Sabril). Vigabatrin is a novel antiepileptic agent, whose action is based on the inhibition of gamma-aminobutyric acid (GABA) aminotransferase, the enzyme responsible for the catabolism of the neurotransmitter GABA. Samples of lumbar cerebrospinal fluid were obtained from the patients prior to commencing vigabatrin therapy, and thereafter at 6 months, 1 year, 2 years, and up to 3 years following the initiation of vigabatrin treatment. The influence of vigabatrin on the cerebrospinal fluid concentrations of free and total GABA, homocarnosine, homovanillic acid, 5-hydroxyindoleacetic acid, and 3-methoxy-4-hydroxyphenylethylene glycol, as well as of the drug itself, was assessed. All patients demonstrated a clinical response to vigabatrin, and the drug was well tolerated over the entire observation period. Mean (+/- SD) reduction of seizure frequency was 65% +/- 23% (range, 26% to 100%) when comparing the end of the treatment period to the previgabatrin baseline. The cerebrospinal fluid concentrations of both free and total GABA and of the dipeptide homocarnosine showed approximately 2- to 5-fold increases over baseline values, with free GABA and homocarnosine being the more sensitive variables. Cerebrospinal fluid concentrations of homovanillic acid, 5-hydroxyindoleacetic acid, and 3-methoxy-4-hydroxyphenylethylene glycol were not altered in a significant manner over the observation period. These findings support the concept that the effects of vigabatrin are restricted to an effect on GABA catabolism and do not extend to the neurotransmitters dopamine and norepinephrine. Clinical efficacy and elevation of GABA and homocarnosine concentration were sustained over the period of observation.

  16. 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

  17. 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.

  18. 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.

  19. Development of next-generation mapping populations: Multi-parent Advanced Generation Inter-Cross (MAGIC) and Marker-Assisted Recurrent Selection (MARS) populations in peanut

    USDA-ARS?s Scientific Manuscript database

    Generation Inter-Cross (MAGIC) and Marker-Assisted Recurrent Selection (MARS) have been proposed and used in many crops to dissect complex traits or QTL. MAGIC allows for dissecting genomic structure, and for improving breeding populations by integrating multiple alleles from different parents. MAR...

  20. Concentrations of selected heavy metals in benthic diatoms and sediment in the Westerschelde Estuary

    SciTech Connect

    Absil, M.C.P.; Scheppingen, Y. van

    1996-12-31

    In recent years considerable data have been compiled on heavy metal levels in biota in marine and estuarine environments. With respect to the fauna, much information is available on accumulation and effects of heavy metals in birds, fish and benthic macrofauna. Accumulation of heavy metals in aquatic flora has been studied mostly in benthic macroalgae, in particular in relation to the use as a biological monitor. The response of planktonic algal species to heavy metals has been studied extensively in cultured populations. Also. heavy metal concentrations in natural plankton have been studied. As far as we know, very few data are available on the concentrations of heavy metals in the lowest benthic trophic level, the benthic microflora. It is a major food supply for numerous intertidal species, so it is obvious that microflora might play an important role in the accumulation of contaminants through coastal food chains. The aim of this research was to adjust a recently developed collection technique for benthic diatoms so that it is suitable for large-scale field studies. The method was then used to assess the concentration of the heavy metals Cd, Cu, Pb and Zn in benthic diatoms and sediments along an estuarine gradient. 18 refs., 2 figs., 1 tab.

  1. 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.

  2. 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.

  3. Minimum inhibitory concentrations of selected antimicrobials against Escherichia coli and Trueperella pyogenes of bovine uterine origin.

    PubMed

    de Boer, Melvin; Heuer, Cord; Hussein, Hassan; McDougall, Scott

    2015-07-01

    Minimum inhibitory concentrations (MIC) of 9 antimicrobials for isolates of 2 common bovine intrauterine bacterial pathogens, Escherichia coli (n=209) and Trueperella pyogenes (n=35), were determined using broth microdilution methodology. The isolates were recovered from dairy cows from 7 herds postpartum using the cytobrush technique. The pathogens were initially identified using phenotypic techniques. Additionally, PCR was used to confirm the identity of T. pyogenes isolates and to categorize the E. coli isolates into phylogenetic groups A, B1, B2, and D. Minimum inhibitory concentrations in excess of published cut-points or bimodal distributions of MIC indicated potential antimicrobial resistance to ampicillin, cefuroxime, cephapirin, and oxytetracycline for E. coli, and to oxytetracycline for T. pyogenes. Of the antimicrobials tested, ticarcillin/clavulanic acid, ceftiofur, and enrofloxacin had the lowest MIC for these 2 pathogens. Differences in MIC of some antimicrobials were found between herds, age, breeds, and E. coli phylogenetic groups. Isolation of E. coli with an MIC ≥8μg/mL of oxytetracycline at 23d postpartum was associated with a lower probability of pregnancy within 6wk of commencement of breeding compared with those isolates with an MIC <8μg/mL (relative risk=0.66). Minimum inhibitory concentrations for uterine pathogens were determined for isolates from New Zealand dairy cows. However, in the absence of either epidemiological or clinical interpretive criteria, the interpretation of these MIC remains unclear. Further studies are required to define interpretative criteria, including determination of pharmacokinetic and pharmacodynamic profiles for antimicrobials.

  4. Volatile generation in bell peppers during frozen storage and thawing using selected ion flow tube mass spectrometry (SIFT-MS).

    PubMed

    Wampler, Brendan; Barringer, Sheryl A

    2012-06-01

    To determine volatile formation during storage and thawing, whole, pureed, blanched, and raw green and red bell peppers (Capsicum annuum) were frozen quickly or slowly then stored at -18 °C for up to 7 mo, with and without SnCl(2) addition during thawing. Headspace analysis was performed by a Selected Ion Flow Tube Mass Spectrometer (SIFT-MS). After blanching, (Z)-3-hexenal had a large significant decrease in concentration since it is a heat labile compound while most other volatiles did not change in concentration. The freezing process increased volatile levels in the puree only. Slow freeze peppers had higher levels of some LOX generated volatiles during storage than quick freeze. During frozen storage of blanched samples (E)-2-hexenal, (Z and E)-hexen-1-ol, and (E)-2-pentenal increased likely because of nonenzymatic autoxidation of fatty acids while other volatiles remained constant. In Raw Whole peppers, (Z)-3-hexenal, hexanal, and 2-pentylfuran were generated during storage likely because the LOX enzyme is still active during frozen storage. However, blanched samples had higher concentrations of (E)-2-hexenal, (Z and E)-hexen-1-ol, 1-penten-3-one, and (E)-2-heptenal because of enzymatic destruction of these volatiles in the raw samples. The levels of many of the volatiles in the raw samples, including (Z)-3-hexenal, (E)-2-hexenal, (Z and E)-hexen-1-ol, hexanal, (E)-2-pentenal, and 2-pentylfuran, appeared to peak around 34 d after freezing. Pureed samples had significantly higher levels of volatiles than the whole samples, and volatiles peaked earlier. Green bell pepper volatile levels were always higher than red bell pepper. Significantly higher volatile formation occurred during thawing than it did during frozen storage. Studying and monitoring the headspace volatiles with a SIFT-MS can give information that will help manufacturers better understand how the volatiles in bell peppers change during frozen storage. This will give valuable information to

  5. 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.

  6. Generation and entanglement concentration for electron-spin entangled cluster states using charged quantum dots in optical microcavities

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; Zheng, Chun-Hong; Shi, Peng; Ren, Chun-Nian; Gu, Yong-Jian

    2014-07-01

    We present schemes for deterministically generating multi-qubit electron-spin entangled cluster states by the giant circular birefringence, induced by the interface between the spin of a photon and the spin of an electron confined in a quantum dot embedded in a double-sided microcavity. Based on this interface, we construct the controlled phase flip (CPF) gate deterministically which is performed on electron-spin qubits and is the essential component of the cluster-state generation. As one of the universal gates, the CPF gate constructed can also be utilized in achieving scalable quantum computing. Besides, we propose the entanglement concentration protocol to reconstruct a partially entangled cluster state into a maximally entangled one, resorting to the projection measurement on an ancillary photon. By iterating the concentration scheme several times, the maximum success probability can be achieved. The fidelities and experimental feasibilities are analyzed with respect to currently available techniques, indicating that our schemes can work well in both the strong and weak (Purcell) coupling regimes.

  7. 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.

  8. Development of a second-generation linear Fresnel lens photovoltaic and thermal (PVT) concentrator array, including fabrication and installation of a 200 square meter collector field

    SciTech Connect

    O'Neill, M.J.

    1985-02-01

    This report summarizes work performed in two areas: development of a second-generation linear Fresnel lens photovoltaic concentrator array, and development and fabrication of a 22 kilowatt photovoltaic and thermal concentrator array. Under these programs, ENTECH, Inc. developed a new second-generation linear Fresnel lens PVT concentrator system, and deployed a 200 square meter collector field of the new design at Sandia-Albuquerque. The new system combines excellent performance and low mass-production cost.

  9. Effects of subthalamic deep brain stimulation on noun/verb generation and selection from competing alternatives in Parkinson's disease.

    PubMed

    Castner, J E; Chenery, H J; Silburn, P A; Coyne, T J; Sinclair, F; Smith, E R; Copland, D A

    2008-06-01

    Impaired generation of verbs relative to nouns has been reported in Parkinson's disease (PD) and has been associated with the frontal pathophysiology of PD. The aim of the present study was to measure noun/verb generation abilities in PD and to determine whether noun/verb generation is affected by stimulation of the subthalamic nucleus (STN). 8 participants who had been diagnosed with PD and had received surgery for deep brain stimulation (DBS) of the STN as well as 15 control participants completed a noun/verb generation task with four probe-response conditions-namely, noun-noun, verb-noun, noun-verb and verb-verb conditions. Patients with PD were assessed while receiving STN stimulation and without stimulation. During the off stimulation condition, patients with PD presented with a selective deficit in verb generation compared with control participants. However, when receiving STN stimulation, patients with PD produced significantly more errors than controls during the noun-noun and verb-verb conditions, supporting evidence from previous studies that STN stimulation modulates a frontotemporal network associated with word generation. Finally, errors during verb generation were significantly correlated with item selection constraint (ie, the degree to which a response competes with other response alternatives) in the on stimulation condition, but not the off stimulation condition. Our results suggest that STN stimulation affects the ability to select from many competing lexical alternatives during verb generation.

  10. Aflatoxin production in peanut lines selected to represent a range of linoleic acid concentrations.

    PubMed

    Xue, H Q; Isleib, T G; Payne, G A; Novitzky, W F; OBrian, G

    2005-01-01

    To determine whether concentrations of linoleate in peanut (Arachis hypogaea L.) seed oil could be used to predict an ability to support aflatoxin production, seeds of genotypes representing a range of linoleate content were inoculated with Aspergillus flavus Link ex Fries and assayed for aflatoxin content. Seeds were blanched and quartered, inoculated with conidia of A. flavus, placed on moistened filter paper in petri dishes, and incubated for 8 days at 28 degrees C. Multiple regression analysis was used to account for the variation among lines with the use of fatty acid concentrations as independent variables. In test 1, linoleate accounted for 39 to 44% of the variation among lines for aflatoxin B1 and B2 and total aflatoxin (26 to 27% after log transformation). Oleate accounted for substantial additional variation (27 to 29%) among lines (20 to 23% after log transformation). Other fatty acids accounted for small fractions of among-line variation. In test 2, linoleate accounted for about 35 to 44% of the variation among entries across traits (29 to 37% for log-transformed data); arachidate accounted for 19 to 29% (27 to 33% after log transformation). Eicosenoate accounted for a small part of the total entry variation. In both experiments, residual variation among entries was significant. Low-linoleate lines consistently contained more aflatoxin, whereas normal- to high-linoleate lines contained variable amounts. Although fatty acid concentrations accounted for significant portions of genetic variation, it is not practical to use them as predictors for susceptibility to aflatoxin contamination, especially for lines in the normal range for oleate and linoleate.

  11. Water-level measurements and chloride concentrations for selected wells in Louisiana, January 1988-October 1997

    USGS Publications Warehouse

    Lovelace, Wendell M.

    2002-01-01

    This report presents water-level measurements and chlorideconcentrations in water from selected wells completed in aquifers in Louisiana. The data were collected during the period January1988-October 1997. Water-level data are presented for 109 wells, and chloride data are presented for 45 wells. Hydrographs and summaries of water-level trends are presented for wellscompleted in aquifers throughout the State. Chlorographs and summaries of chloride trends are presented for wells completed in the Mississippi River alluvial and Sparta aquifers; Chicot aquifer system; and Gramercy, Norco, and Gonzales-New Orleans aquifers. Data are presented in graphical and tabular formats.

  12. Impact of low-energy CT imaging on selection of positive oral contrast media concentration.

    PubMed

    Patino, Manuel; Murcia, Diana J; Iamurri, Andrea Prochowski; Kambadakone, Avinash R; Hahn, Peter F; Sahani, Dushyant V

    2017-05-01

    To determine to what extent low-energy CT imaging affects attenuation of gastrointestinal tract (GIT) opacified with positive oral contrast media (OCM). Second, to establish optimal OCM concentrations for low-energy diagnostic CT exams. One hundred patients (38 men and 62 women; age 62 ± 11 years; BMI 26 ± 5) with positive OCM-enhanced 120-kVp single-energy CT (SECT), and follow-up 100-kVp acquisitions (group A; n = 50), or 40-70-keV reconstructions from rapid kV switching-single-source dual-energy CT (ssDECT) (group B; n = 50) were included. Luminal attenuation from different GIT segments was compared between exams. Standard dose of three OCM and diluted solutions (75%, 50%, and 25% concentrations) were introduced serially in a gastrointestinal phantom and scanned using SECT (120, 100, and 80 kVp) and DECT (80/140 kVp) acquisitions on a ssDECT scanner. Luminal attenuation was obtained on SECT and DECT images (40-70 keV), and compared to 120-kVp scans with standard OCM concentrations. Luminal attenuation was higher on 100-kVp (328 HU) and on 40-60-keV images (410-924 HU) in comparison to 120-kVp scans (298 HU) in groups A and B (p < 0.05). Phantom: There was an inverse correlation between luminal attenuation and X-ray energy, increasing up to 527 HU on low-kVp and 999 HU on low-keV images (p < 0.05). 25% and 50% diluted OCM solutions provided similar or higher attenuation than 120 kVp, at low kVp and keV, respectively. Low-energy CT imaging increases the attenuation of GIT opacified with positive OCM, permitting reduction of 25%-75% OCM concentration.

  13. Development of the selection and manipulation of self-generated thoughts in adolescence.

    PubMed

    Dumontheil, Iroise; Hassan, Bano; Gilbert, Sam J; Blakemore, Sarah-Jayne

    2010-06-02

    The ability to select and manipulate self-generated (stimulus-independent, SI), as opposed to stimulus-oriented (SO), information, in a controlled and flexible way has previously only been studied in adults. This ability is thought to rely in part on the rostrolateral prefrontal cortex (RLPFC), which continues to mature anatomically during adolescence. We investigated (1) the development of this ability behaviorally, (2) the associated functional brain development, and (3) the link between functional and structural maturation. Participants classified according to their shape letters either presented visually (SO phases) or that they generated in their head by continuing the alphabet sequence (SI phases). SI phases were performed in the presence or absence of distracting letters. A total of 179 participants (7-27 years old) took part in a behavioral study. Resistance to visual distractors exhibited small improvements with age. SI thoughts manipulation and switching between SI and SO thoughts showed steeper performance improvements extending into late adolescence. Thirty-seven participants (11-30 years old) took part in a functional MRI (fMRI) study. SI thought manipulation and switching between SO and SI thought were each associated with brain regions consistently recruited across age. A single frontal brain region in each contrast exhibited decreased activity with age: left inferior frontal gyrus/anterior insula for SI thought manipulation, and right superior RLPFC for switching between SO and SI thoughts. By integrating structural and functional data, we demonstrated that the observed functional changes with age were not purely consequences of structural maturation and thus may reflect the maturation of neurocognitive strategies.

  14. Environmental concentration of selected elements and relation to physicochemical parameters in honey.

    PubMed

    Kacaniova, Miroslava; Knazovicka, Vladimira; Melich, Martin; Fikselova, Martina; Massanyi, Peter; Stawarz, Robert; Hascik, Peter; Pechociak, Tomas; Kuczkowska, Anna; Putała, Aldona

    2009-03-01

    The purpose of this study was to evaluate the content of selected elements and physicochemical indicators of the honey of Apis mellifera. Samples of blossom, blend and honeydew honeys were randomly obtained from the Eastern, Western and Central of Slovakia. Contents of elements were measured with the use of flame atomic absorption spectrophotometry (FAAS) method and anodic stripping voltammetry (ASV) method with CGMDE as working electrode. The content of heavy metals (mg/kg dry weight) ranged as follows: Zn 0.25-3.82; Cu 0.12-1.37; Ni 0.06-0.60; Mg 0.10-50.43; Ca 10.32-87.21; Pb and Cd were under detectable limit (0.001 mg/kg). The physical and chemical indicators ranged as follows: moisture (%) 16.00-19.80; HMF (mg/kg) 10.00-40.00; pH 3.58-5.12; conductivity (mS/m) 13.45-99.12 and a(w) 0.456-0.659. Significant difference (P < 0.05) for elements and physicochemical indicators was analyzed. Significant correlations between Cu - Zn, Cu - Ni, Cu - Mg, Ca - Zn and Ca - Mg were detected. With reference to Codex Alimentarius of Slovakia, maximal levels of heavy metals content and selected physicochemical properties were not exceeded. On average, the content of trace elements decreased in the order: Ca > Mg > Zn > Cu > Ni and physicochemical indicators decreased: conductivity > HMF > moisture > pH > a(w).

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

    PubMed

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

    2015-03-04

    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.

  16. 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.

  17. Concentrations of selected metals in candies and chocolates consumed in southern Nigeria.

    PubMed

    Iwegbue, Chukwujindu M A

    2011-01-01

    Results are presented for the determination of levels of Ca, Cd, Ni, Cr, Cu, Pb, Mn, Zn Fe, Co and Mg in candies and chocolates consumed in southern Nigeria. Mean concentrations of metals in both confectionaries ranged 7.7-1405.2 µg/g¹ for Ca, <0.001-0.2 µg/g for Cd, 1.4-7.9 µg/g for Ni, 0.4-3.0 µg/g for Cr, <0.08-2.3 µg/g for Pb, 0.4-12.6 µg/g for Mn, 0.6-8.0 µg/g for Zn, 1.7-12.3 µg/g for Fe, <0.05-1.49 µg/g for Co, and 8.4-576.1 µg/g for Mg. The data showed that that these metals are not present at harmful levels. Concentrations of nickel and chromium were slightly elevated but were comparable to levels reported in similar food items elsewhere in the world.

  18. Selection of Amikacin Hyper-Resistant Pseudomonas aeruginosa After Stepwise Exposure to High Amikacin Concentrations.

    PubMed

    Amábile-Cuevas, Carlos F

    2017-01-01

    Aerosolized amikacin reaches high concentrations in lung fluids, which are well above the minimum inhibitory concentrations (MICs) of resistant strains of Pseudomonas aeruginosa. However, P. aeruginosa can gain resistance to amikacin through different cumulative mechanisms; amikacin MICs are seldom reported beyond values of 1,000 μg/ml, as tested in clinical microbiology assays. To assess how high amikacin MICs can be reached by graded exposure, four amikacin-resistant P. aeruginosa isolates were grown in a 4-step increased exposure to amikacin; derivative strains were further characterized by measuring their comparative growth rate, biofilm-forming ability, and susceptibility to other antibiotics. In addition, the mechanism underlying the MIC increase was assessed phenotypically, using a set of 12 aminoglycoside disks, and measuring the effect of Phe-Arg-β-naphthylamide, an efflux pump inhibitor. Graded exposure to amikacin increased MICs of resistant strains up to 10,000-20,000 μg/ml, without apparent fitness cost, and having variable consequences on their biofilm-forming ability, and on their susceptibility to other antibiotics. Decreased permeability may have contributed to hyper-resistance, although evidence was inconclusive and variable between strains. Amikacin-resistant P. aeruginosa is able to gain in vitro hyper-resistance with minimal changes in the specific phenotypes that were tested; the ability to achieve high-level amikacin (AMK) resistance may confound the clinical utility of this aerosolized AMK, but clinical data would be required to assess this.

  19. Assessment of immunoglobulin concentrates on thrombogenic activity by thrombin generation assay, prekallikrein activator assay, and size-exclusion chromatography.

    PubMed

    Seifner, Alexandra; Beck, Gerhard; Bayer, Patrick; Eichmeir, Stephanie; Lackner, Friedrich; Rögelsperger, Olga; Weber, Katharina; Wollein, Gabriele

    2014-02-01

    Immunoglobulin G (IgG) concentrates have recently been found to be contaminated with procoagulant impurities causing thromboembolic events (TEEs) in vivo. In this study the question was raised whether a thrombin generation assay (TGA) will be able to characterize IgG samples from the Austrian market with regard to their thrombogenic potential. A total of 44 IgG concentrates have been assayed by TGA employing pooled normal plasma and Factor (F)XI-deficient plasma (FXIdp). Furthermore, the prekallikrein activator assay including determination of blank values, size-exclusion chromatography, and further test systems required for batch release testing of IgG concentrates according to the European Pharmacopeia (Pharm. Eur.) were carried out. All samples complied with acceptance criteria stated in the Plarm. Eur. and/or prescribed by the marketing approval. One intravenous immunoglobulin (IVIG) involved in TEEs exceeded a threshold level of 350 nmol peak thrombin, which was not exceeded after change of manufacture and by all the other IVIGs tested. Two hyperimmune globulins revealed elevated peak thrombin levels of up to 810 nmol in FXI and up to 285 nmol in FXIdp. The study indicates that the TGA is able to reliably predict procoagulant activities probably associated with the presence of FXIa and potential thrombogenicity. Comparison of thrombin generation with product-specific acceptance criteria as well as variables from other test systems as amidolytic activity and molecular size can help to monitor IgG quality and manufacturing changes with regard to thrombogenicity. © 2013 American Association of Blood Banks.

  20. The effect of PAMAM dendrimer concentration, generation size and surface functional group on the aqueous solubility of candesartan cilexetil.

    PubMed

    Ertürk, Ali Serol; Gürbüz, Mustafa Ulvi; Tülü, Metin

    2017-02-01

    This article investigates the aqueous solubility of the poorly soluble drug candesartan cilexetil (CC) in the presence of poly(amidoamine) (PAMAM) dendrimers. The effect of variables such as concentration, generation size (G2-G4), and surface groups (NH2, COOH and TRIS) of PAMAMs on the aqueous solubility of CC was studied. A two-factor factorial (3 × 3) ANOVA design was used to study the effect of generation size and surface functional group of the PAMAMs. The results showed that the aqueous solubility of CC in the presence of carboxyl and TRIS-terminated PAMAMs was higher than those of amine-terminated PAMAMs, and the effect of surface functional group of the PAMAMs on the aqueous solubility of CC was dependent on the generation size (p < 0.05). The sequence of the observed solubility fold enhancement due to PAMAMs was G4.COOH (8378)>G3.COOH (3456)>G4.TRIS (2362)>G2.COOH (1013)>G3.TRIS (749)>G2.TRIS (293)>G4.NH2 (91)>G3.NH2 (50)>G2.NH2 (37). The CC-PAMAM dendrimer inclusion complexes were characterized by UV-Vis, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and differential thermal analysis (DTA) techniques. Regarding the results of these techniques, improvement in the solubility of CC is expected primarily through the intermolecular hydrogen bonding between the drug and internal tertiary and surface functional groups of the studied PAMAMs.

  1. Distribution of Phosphorus Atoms and Carrier Concentrations in Single-Crystal Silicon Doped by Catalytically Generated Phosphorous Radicals

    NASA Astrophysics Data System (ADS)

    Hayakawa, Taro; Nakashima, Yuki; Koyama, Koichi; Ohdaira, Keisuke; Matsumura, Hideki

    2012-06-01

    A phosphorus (P)-doped ultrathin n+ layer is formed on crystalline silicon (c-Si) using radicals generated by the catalytic cracking reaction of phosphine (PH3) gas with a heated catalyzer. The carrier concentration and the depth distributions of P atoms are investigated by Hall effect and secondary ion mass spectrometry (SIMS), respectively. The surface of the p-type c-Si substrate is converted to n-type c-Si by this doping even at a substrate temperature of 20 °C, when the tungsten (W) catalyzer is heated at 1300 °C. SIMS measurements demonstrate that P atoms exist on the c-Si surface. However, the distributions of P atoms obtained by SIMS do not change, even for the increase in substrate temperature from 80 to 350 °C or the increase in radical exposure time from 60 to 3600 s. Although the sheet carrier concentration increased with the substrate temperature, the sheet carrier concentration increased only slightly with the radical exposure time. It is revealed that the doping mechanism does not appear to be the same as that of the thermal diffusion, but that the reaction of the P-related species with Si atoms on the surface plays a key role for this radical doping.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Tangential flow ultrafiltration: a "green" method for the size selection and concentration of colloidal silver nanoparticles.

    PubMed

    Anders, Catherine B; Baker, Joshua D; Stahler, Adam C; Williams, Austin J; Sisco, Jackie N; Trefry, John C; Wooley, Dawn P; Pavel Sizemore, Ioana E

    2012-10-04

    Nowadays, AgNPs are extensively used in the manufacture of consumer products,(1) water disinfectants,(2) therapeutics,(1, 3) and biomedical devices(4) due to their powerful antimicrobial properties.(3-6) These nanoparticle applications are strongly influenced by the AgNP size and aggregation state. Many challenges exist in the controlled fabrication(7) and size-based isolation(4,8) of unfunctionalized, homogenous AgNPs that are free from chemically aggressive capping/stabilizing agents or organic solvents.(7-13) Limitations emerge from the toxicity of reagents, high costs or reduced efficiency of the AgNP synthesis or isolation methods (e.g., centrifugation, size-dependent solubility, size-exclusion chromatography, etc.).(10,14-18) To overcome this, we recently showed that TFU permits greater control over the size, concentration and aggregation state of Creighton AgNPs (300 ml of 15.3 μg ml(-1) down to 10 ml of 198.7 μg ml(-1)) than conventional methods of isolation such as ultracentrifugation.(19) TFU is a recirculation method commonly used for the weight-based isolation of proteins, viruses and cells.(20,21) Briefly, the liquid sample is passed through a series of hollow fiber membranes with pore size ranging from 1,000 kD to 10 kD. Smaller suspended or dissolved constituents in the sample will pass through the porous barrier together with the solvent (filtrate), while the larger constituents are retained (retentate). TFU may be considered a "green" method as it neither damages the sample nor requires additional solvent to eliminate toxic excess reagents and byproducts. Furthermore, TFU may be applied to a large variety of nanoparticles as both hydrophobic and hydrophilic filters are available. The two main objectives of this study were: 1) to illustrate the experimental aspects of the TFU approach through an invited video experience and 2) to demonstrate the feasibility of the TFU method for larger volumes of colloidal nanoparticles and smaller volumes of

  7. 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.

  8. Evaluation of serum concentrations of the selected cytokines in patients with localized scleroderma

    PubMed Central

    Budzyńska-Włodarczyk, Jolanta; Michalska-Jakubus, Małgorzata M.; Kowal, Małgorzata

    2016-01-01

    Introduction Localized scleroderma is an autoimmune disease primarily affecting the skin. The cause of disease remains unexplained although environmental factors are implicated, which are likely to be responsible for activation of the endothelium and subsequent inflammation leading to excessive synthesis of collagen and extracellular matrix components. Aim To determine concentrations of interleukin (IL)-27, transforming growth factor (TGF)-β1, TGF-β2, IL-6, and sIL-6R in patients with localized scleroderma compared to controls and to assess the relations between their levels and laboratory markers. Material and methods The study encompassed 17 females with localized scleroderma (aged 25–67). The control group consisted of 30 age-matched healthy women. The blood was sampled from the basilic vein. Serum levels of cytokines were determined using ELISA. Results The TGF-β2 levels were found to be significantly lower in patients with localized scleroderma compared to controls. Concentrations of TGF-β1 were decreased in scleroderma patients when compared to controls but without statistical significance. There were no significant differences in serum IL-6, sIL-6R and IL-27 levels between patients and the control group; however, we found a significant positive correlation between the level of sIL-6 and ESR among subjects with localized scleroderma. Conclusions The findings of decreased serum levels of TGF-β1 and TGF-β2 in patients with localized scleroderma demonstrate a possible association of these cytokines with pathogenesis of the disease. The results suggest also that sIL-6R is likely to be involved in inflammation in patients with localized scleroderma. PMID:26985179

  9. Concentrations of selected volatile organic compounds at kerbside and background sites in central London

    NASA Astrophysics Data System (ADS)

    Valach, A. C.; Langford, B.; Nemitz, E.; MacKenzie, A. R.; Hewitt, C. N.

    2014-10-01

    Ground-level concentrations of nine volatile organic compounds (VOCs) were measured using a proton transfer reaction-mass spectrometer (PTR-MS) in central London at an urban background (North Kensington, NK, during 16th-25th Jan 2012) and a kerbside site (Marylebone Rd, MRd, during 25th Jan-7th Feb 2012) as part of the winter intensive observation period of the ClearfLo project. Site comparisons indicated that VOC concentrations at the urban background site were significantly lower than at the kerbside site (ratio MRd/NK of 2.3). At the kerbside site PTR-MS measurements of aromatics (benzene, toluene, C2- and C3-benzenes) were compared with the gas chromatography - flame ionization detector data from the UK Government's Automatic Hydrocarbon Network. Very good qualitative agreement was observed between the two methods (r = 0.90-0.91, p < 0.001, N = 260), although there was a significant offset between the instruments. This was partly due to issues with humidity dependent background measurements, but possibly also from isobaric interference of other compounds and their fragments, giving a positive bias to the PTR-MS data. Most compounds showed strong indications of traffic-related sources with double rush hour peaks in diurnal profiles and high correlations with known traffic-related compounds (r = 0.68-0.97 at NK, 0.48-0.87 at MRd, p < 0.001, NNK = 2202-2227, NMRd = 2705-2720) and CO (r = 0.80-0.96 at NK, 0.65-0.84 at MRd, p < 0.001, NNK = 223, NMRd = 256-274). Polar plots agreed with statistical analysis of wind direction dependency and identification of potential emission sources was attempted.

  10. Evaluation of serum concentrations of the selected cytokines in patients with localized scleroderma.

    PubMed

    Budzyńska-Włodarczyk, Jolanta; Michalska-Jakubus, Małgorzata M; Kowal, Małgorzata; Krasowska, Dorota

    2016-02-01

    Localized scleroderma is an autoimmune disease primarily affecting the skin. The cause of disease remains unexplained although environmental factors are implicated, which are likely to be responsible for activation of the endothelium and subsequent inflammation leading to excessive synthesis of collagen and extracellular matrix components. To determine concentrations of interleukin (IL)-27, transforming growth factor (TGF)-β1, TGF-β2, IL-6, and sIL-6R in patients with localized scleroderma compared to controls and to assess the relations between their levels and laboratory markers. The study encompassed 17 females with localized scleroderma (aged 25-67). The control group consisted of 30 age-matched healthy women. The blood was sampled from the basilic vein. Serum levels of cytokines were determined using ELISA. The TGF-β2 levels were found to be significantly lower in patients with localized scleroderma compared to controls. Concentrations of TGF-β1 were decreased in scleroderma patients when compared to controls but without statistical significance. There were no significant differences in serum IL-6, sIL-6R and IL-27 levels between patients and the control group; however, we found a significant positive correlation between the level of sIL-6 and ESR among subjects with localized scleroderma. The findings of decreased serum levels of TGF-β1 and TGF-β2 in patients with localized scleroderma demonstrate a possible association of these cytokines with pathogenesis of the disease. The results suggest also that sIL-6R is likely to be involved in inflammation in patients with localized scleroderma.

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

    PubMed

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

    2016-06-13

    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.

  12. 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

  13. Effects of sludge retention time, carbon and initial biomass concentrations on selection process: From activated sludge to polyhydroxyalkanoate accumulating cultures.

    PubMed

    Chen, Zhiqiang; H