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Sample records for highly concentrated hyperpolarized

  1. Hyperpolarized NMR Probes for Biological Assays

    Directory of Open Access Journals (Sweden)

    Sebastian Meier

    2014-01-01

    Full Text Available During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.

  2. Low-Cost, High-Throughput 3-D Pulmonary Imager Using Hyperpolarized Contrast Agents and Low-Field MRI

    Science.gov (United States)

    2017-10-01

    low- cost and high-throughput was a key element proposed for this project, which we believe will be of significant benefit to the patients suffering...Award Number: W81XWH-15-1-0272 TITLE: Low- Cost , High-Throughput 3-D Pulmonary Imager Using Hyperpolarized Contrast Agents and Low-Field MRI...STATEMENT: Approved for Public Release; Distribution Unlimited The views, opinions and/or findings contained in this report are those of the author(s

  3. Low Cost, High-Throughput 3-D Pulmonary Imager Using Hyperpolarized Contrast Agents and Low-Field MRI

    Science.gov (United States)

    2017-10-01

    greater gas polarizations and production amounts/ throughputs- benefiting in particular from the advent of com- pact, high-power, relatively low- cost ...Award Number: W81XWH-15-1-0271 TITLE: Low- Cost , High-Throughput 3-D Pulmonary Imager Using Hyperpolarized Contrast Agents and Low-Field MRI...DISTRIBUTION STATEMENT: Approved for Public Release; Distribution Unlimited The views, opinions and/or findings contained in this report are those of the

  4. Large dose hyperpolarized water with dissolution-DNP at high magnetic field

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Bowen, Sean; Rybalko, Oleksandr

    2016-01-01

    was polarized and dissolved in a fluid path compatible with clinical polarizers. The volume of hyperpolarized water produced by this method enables angiography and perfusion measurements in large animals, as well as NMR experiments for studies of e.g. proton exchange and polarization transfer to other nuclei....

  5. Pulmonary hyperpolarized (129) Xe morphometry for mapping xenon gas concentrations and alveolar oxygen partial pressure: Proof-of-concept demonstration in healthy and COPD subjects.

    Science.gov (United States)

    Ouriadov, A; Farag, A; Kirby, M; McCormack, D G; Parraga, G; Santyr, G E

    2015-12-01

    Diffusion-weighted (DW) hyperpolarized (129) Xe morphometry magnetic resonance imaging (MRI) can be used to map regional differences in lung tissue micro-structure. We aimed to generate absolute xenon concentration ([Xe]) and alveolar oxygen partial pressure (pA O2 ) maps by extracting the unrestricted diffusion coefficient (D0 ) of xenon as a morphometric parameter. In this proof-of-concept demonstration, morphometry was performed using multi b-value (0, 12, 20, 30 s/cm(2) ) DW hyperpolarized (129) Xe images obtained in four never-smokers and four COPD ex-smokers. Morphometric parameters and D0 maps were computed and the latter used to generate [Xe] and pA O2 maps. Xenon concentration phantoms estimating a range of values mimicking those observed in vivo were also investigated. Xenon D0 was significantly increased (P = 0.035) in COPD (0.14 ± 0.03 cm(2) /s) compared with never-smokers (0.12 ± 0.02 cm(2) /s). COPD ex-smokers also had significantly decreased [Xe] (COPD = 8 ± 7% versus never-smokers = 13 ± 8%, P = 0.012) and increased pA O2 (COPD = 18 ± 3% versus never-smokers = 15 ± 3%, P = 0.009) compared with never-smokers. Phantom measurements showed the expected dependence of D0 on [Xe] over the range of concentrations anticipated in vivo. DW hyperpolarized (129) Xe MRI morphometry can be used to simultaneously map [Xe] and pA O2 in addition to providing micro-structural biomarkers of emphysematous destruction in COPD. Phantom measurements of D0 ([Xe]) supported the hypotheses that differences in subjects may reflect differences in functional residual capacity. © 2014 Wiley Periodicals, Inc.

  6. Hyperpolarized 3helium magnetic resonance ventilation imaging of the lung in cystic fibrosis: comparison with high resolution CT and spirometry

    International Nuclear Information System (INIS)

    McMahon, Colm J.; Dodd, Jonathan D.; Skehan, Stephen J.; Masterson, James B.; Hill, Catherine; Woodhouse, Neil; Wild, Jim M.; Fichele, Stan; Gallagher, Charles G.; Beek, Edwin J.R. van

    2006-01-01

    The purpose of this study was to compare hyperpolarized 3 helium magnetic resonance imaging ( 3 He MRI) of the lungs in adults with cystic fibrosis (CF) with high-resolution computed tomography (HRCT) and spirometry. Eight patients with stable CF prospectively underwent 3 He MRI, HRCT, and spirometry within 1 week. Three-dimensional (3D) gradient-echo sequence was used during an 18-s breath-hold following inhalation of hyperpolarized 3 He. Each lung was divided into six zones; 3 He MRI was scored as percentage ventilation per lung zone. HRCT was scored using a modified Bhalla scoring system. Univariate (Spearman rank) and multivariate correlations were performed between 3 He MRI, HRCT, and spirometry. Results are expressed as mean±SD (range). Spirometry is expressed as percent predicted. There were four men and four women, mean age=31.9±9 (20-46). Mean forced expiratory volume in 1 s (FEV) 1 =52%±29 (27-93). Mean 3 He MRI score=74%±25 (55-100). Mean HRCT score=48.8±24 (13.5-83). The correlation between 3 He MRI and HRCT was strong (R=±0.89, p 3 He MRI; 3 He MRI correlated better with FEV 1 and forced vital capacity (FVC) (R=0.86 and 0.93, p 3 He MRI correlates strongly with structural HRCT abnormalities and is a stronger correlate of spirometry than HRCT in CF. (orig.)

  7. Transportable hyperpolarized metabolites

    Science.gov (United States)

    Ji, Xiao; Bornet, Aurélien; Vuichoud, Basile; Milani, Jonas; Gajan, David; Rossini, Aaron J.; Emsley, Lyndon; Bodenhausen, Geoffrey; Jannin, Sami

    2017-01-01

    Nuclear spin hyperpolarization of 13C-labelled metabolites by dissolution dynamic nuclear polarization can enhance the NMR signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by MRI. However, because of the short lifetime of the hyperpolarized magnetization (typically <1 min), the polarization process must be carried out close to the point of use. Here we introduce a concept that markedly extends hyperpolarization lifetimes and enables the transportation of hyperpolarized metabolites. The hyperpolarized sample can thus be removed from the polarizer and stored or transported for use at remote MRI or NMR sites. We show that hyperpolarization in alanine and glycine survives 16 h storage and transport, maintaining overall polarization enhancements of up to three orders of magnitude. PMID:28072398

  8. A continuous-flow, high-throughput, high-pressure parahydrogen converter for hyperpolarization in a clinical setting.

    Science.gov (United States)

    Hövener, Jan-Bernd; Bär, Sébastien; Leupold, Jochen; Jenne, Klaus; Leibfritz, Dieter; Hennig, Jürgen; Duckett, Simon B; von Elverfeldt, Dominik

    2013-02-01

    Pure parahydrogen (pH(2) ) is the prerequisite for optimal pH(2) -based hyperpolarization experiments, promising approaches to access the hidden orders of magnitude of MR signals. pH(2) production on-site in medical research centers is vital for the proliferation of these technologies in the life sciences. However, previously suggested designs do not meet our requirements for safety or production performance (flow rate, pressure or enrichment). In this article, we present the safety concept, design and installation of a pH(2) converter, operated in a clinical setting. The apparatus produces a continuous flow of four standard liters per minute of ≈98% enriched pH(2) at a pressure maximum of 50 bar. The entire production cycle, including cleaning and cooling to 25 K, takes less than 5 h, only ≈45 min of which are required for actual pH(2) conversion. A fast and simple quantification procedure is described. The lifetimes of pH(2) in a glass vial and aluminum storage cylinder are measured to be T(1C) (glass vial) =822 ± 29 min and T(1C) (Al cylinder) =129 ± 36 days, thus providing sufficiently long storage intervals and allowing the application of pH(2) on demand. A dependence of line width on pH(2) enrichment is observed. As examples, (1) H hyperpolarization of pyridine and (13) C hyperpolarization of hydroxyethylpropionate are presented. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Hyperpolarized Nanodiamond Surfaces.

    Science.gov (United States)

    Rej, Ewa; Gaebel, Torsten; Waddington, David E J; Reilly, David J

    2017-01-11

    The widespread use of nanodiamond as a biomedical platform for drug-delivery, imaging, and subcellular tracking applications stems from its nontoxicity and unique quantum mechanical properties. Here, we extend this functionality to the domain of magnetic resonance, by demonstrating that the intrinsic electron spins on the nanodiamond surface can be used to hyperpolarize adsorbed liquid compounds at low fields and room temperature. By combining relaxation measurements with hyperpolarization, spins on the surface of the nanodiamond can be distinguished from those in the bulk liquid. These results are likely of use in signaling the controlled release of pharmaceutical payloads.

  10. Highly concentrating Fresnel lenses

    International Nuclear Information System (INIS)

    Kritchman, E.M.; Friesem, A.A.; Yekutieli, G.

    1979-01-01

    A new type of concave Fresnel lens capable of concentrating solar radiation very near the ultimate concentration limit is considered. The differential equations that describe the lens are solved to provide computed solutions which are then checked by ray tracing techniques. The performance (efficiency and concentration) of the lens is investigated and compared to that of a flat Fresnel lens, showing that the new lens is preferable for concentrating solar radiation. (author)

  11. Hyperpolarized {sup 3}helium magnetic resonance ventilation imaging of the lung in cystic fibrosis: comparison with high resolution CT and spirometry

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, Colm J.; Dodd, Jonathan D.; Skehan, Stephen J.; Masterson, James B. [St. Vincent' s University Hospital, Department of Radiology, Dublin (Ireland); Hill, Catherine; Woodhouse, Neil; Wild, Jim M.; Fichele, Stan [Royal Hallamshire Hospital, The Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); Gallagher, Charles G. [St. Vincent' s University Hospital, Department of National Referral Centre for Adult Cystic Fibrosis, Dublin (Ireland); Beek, Edwin J.R. van [Royal Hallamshire Hospital, The Unit of Academic Radiology, University of Sheffield, Sheffield (United Kingdom); University of Iowa, Department of Radiology, Carver College of Medicine, Iowa City, IA (United States)

    2006-11-15

    The purpose of this study was to compare hyperpolarized {sup 3}helium magnetic resonance imaging ({sup 3}He MRI) of the lungs in adults with cystic fibrosis (CF) with high-resolution computed tomography (HRCT) and spirometry. Eight patients with stable CF prospectively underwent {sup 3}He MRI, HRCT, and spirometry within 1 week. Three-dimensional (3D) gradient-echo sequence was used during an 18-s breath-hold following inhalation of hyperpolarized {sup 3}He. Each lung was divided into six zones; {sup 3}He MRI was scored as percentage ventilation per lung zone. HRCT was scored using a modified Bhalla scoring system. Univariate (Spearman rank) and multivariate correlations were performed between {sup 3}He MRI, HRCT, and spirometry. Results are expressed as mean{+-}SD (range). Spirometry is expressed as percent predicted. There were four men and four women, mean age=31.9{+-}9 (20-46). Mean forced expiratory volume in 1 s (FEV){sub 1}=52%{+-}29 (27-93). Mean {sup 3}He MRI score=74%{+-}25 (55-100). Mean HRCT score=48.8{+-}24 (13.5-83). The correlation between {sup 3}He MRI and HRCT was strong (R={+-}0.89, p<0.001). Bronchiectasis was the only independent predictor of {sup 3}He MRI; {sup 3}He MRI correlated better with FEV{sub 1} and forced vital capacity (FVC) (R=0.86 and 0.93, p<0.01, respectively) than HRCT (R={+-}0.72 and {+-}0.81, p<0.05, respectively). This study showed that {sup 3}He MRI correlates strongly with structural HRCT abnormalities and is a stronger correlate of spirometry than HRCT in CF. (orig.)

  12. Ultra flat ideal concentrators of high concentration

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, Julio [IST, Physics Dept., Lisboa (Portugal); INETI-DER, Lisboa (Portugal); Collares-Pereira, Manuel [INETI-DER, Lisboa (Portugal)

    2000-07-01

    A new method for the design of nonimaging devices is presented. Its application to the design of ultra flat compact concentrators is analysed. These new concentrators are based on a combination of two stages: the first one is composed of a large number of small structures placed side by side and the second one is a very compact single device concentrating the radiation to the limit. These devices are ideal for 2D. These compact designs are much more compact than the traditional ones like lens-mirror combinations or parabolic primaries with nonimaging secondaries. Besides, they can be designed for any acceptance angle, while the traditional ones are limited to small acceptance angles. (Author)

  13. Ionic channels and membrane hyperpolarization in human macrophages

    NARCIS (Netherlands)

    Ince, C.; van Duijn, B.; Ypey, D. L.; van Bavel, E.; Weidema, F.; Leijh, P. C.

    1987-01-01

    Microelectrode impalement of human macrophages evokes a transient hyperpolarizing response (HR) of the membrane potential. This HR was found to be dependent on the extracellular concentration of K+ but not on that of Na+ or Cl-. It was not influenced by low temperature (12 degrees C) or by 0.2 mM

  14. High concentration agglomerate dynamics at high temperatures.

    Science.gov (United States)

    Heine, M C; Pratsinis, S E

    2006-11-21

    The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

  15. Hyperpolarized singlet NMR on a small animal imaging system

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Pileio, Giuseppe; Tayler, Michael C. D.

    2012-01-01

    Nuclear spin hyperpolarization makes a significant advance toward overcoming the sensitivity limitations of in vivo magnetic resonance imaging, particularly in the case of low-gamma nuclei. The sensitivity may be improved further by storing the hyperpolarization in slowly relaxing singlet...... populations of spin- 1/2 pairs. Here, we report hyperpolarized 13C spin order transferred into and retrieved from singlet spin order using a small animal magnetic resonance imaging scanner. For spins in sites with very similar chemical shifts, singlet spin order is sustained in high magnetic field without...... requiring strong radiofrequency irradiation. The demonstration of robust singlet-to-magnetization conversion, and vice versa, on a small animal scanner, is promising for future in vivo and clinical deployments....

  16. Enhanced excitatory input to melanin concentrating hormone neurons during developmental period of high food intake is mediated by GABA.

    Science.gov (United States)

    Li, Ying; van den Pol, Anthony N

    2009-12-02

    In contrast to the local axons of GABA neurons of the cortex and hippocampus, lateral hypothalamic neurons containing melanin concentrating hormone (MCH) and GABA send long axons throughout the brain and play key roles in energy homeostasis and mental status. In adults, MCH neurons maintain a hyperpolarized membrane potential and most of the synaptic input is inhibitory. In contrast, we found that developing MCH neurons received substantially more excitatory synaptic input. Based on gramicidin-perforated patch recordings in hypothalamic slices from MCH-green fluorescent protein transgenic mice, we found that GABA was the primary excitatory synaptic transmitter in embryonic and neonatal ages up to postnatal day 10. Surprisingly, glutamate assumed only a minor excitatory role, if any. GABA plays a complex role in developing MCH neurons, with its actions conditionally dependent on a number of factors. GABA depolarization could lead to an increase in spikes either independently or in summation with other depolarizing stimuli, or alternately, depending on the relative timing of other depolarizing events, could lead to shunting inhibition. The developmental shift from depolarizing to hyperpolarizing occurred later in the dendrites than in the cell body. Early GABA depolarization was based on a Cl(-)-dependent inward current. An interesting secondary depolarization in mature neurons that followed an initial hyperpolarization was based on a bicarbonate mechanism. Thus during the early developmental period when food consumption is high, MCH neurons are more depolarized than in the adult, and an increased level of excitatory synaptic input to these orexigenic cells is mediated by GABA.

  17. Hyperpolarized 129Xe as an NMR probe for functional studies

    International Nuclear Information System (INIS)

    Wolber, J.

    2000-01-01

    The nuclear spin polarization of 129 Xe can be enhanced by several orders of magnitude using optical pumping techniques, resulting in a dramatic enhancement of the 129 Xe Nuclear Magnetic Resonance (NMR) signal. The 'hyperpolarized' gas can be used for Magnetic Resonance Imaging (MRI) of the void spaces of the lungs after introduction of the gas into the respiratory system. Furthermore, the high solubility of xenon in blood and lipids suggests the use of 129 Xe NMR for studying blood flow, permeability, perfusion and blood volume. Hyperpolarized 129 Xe MRI has the potential of combining the high sensitivity and functional information of radioactive tracer studies with the high spatial and temporal resolution of MRI. The spin-lattice relaxation time T 1 of 129 Xe in blood determines the loss of polarization during transit from the lungs to the tissue of interest. A difference in the relaxation times of xenon in oxygenated and deoxygenated blood could be used as a contrast mechanism in functional Magnetic Resonance Imaging (fMRI). In this thesis, the hyperpolarized 129 Xe T 1 in human blood is measured in vitro as a function of blood oxygenation, and the relevant relaxation mechanisms are discussed. A new and unexpected finding is that the hyperpolarized 129 Xe NMR spectrum in blood is highly sensitive to blood oxygenation. Therefore, hyperpolarized 129 Xe NMR provides a powerful means of measuring blood oxygenation quantitatively and non-invasively. The interaction of xenon with hemoglobin is responsible for an oxygen-dependent shift of the 129 Xe NMR resonance of xenon in red blood cells. Injection delivery of hyperpolarized 129 Xe in solution could be a more efficient method of administrating the gas for functional NMR studies. For this purpose, suitable biocompatible carrier media have been studied. In particular, the use of perfluorocarbon emulsions, which are already in use as blood substitutes, as delivery media for hyperpolarized 129 Xe has been investigates

  18. Hyperpolarized C-13 MRS Cardiac Metabolism Studies in Pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Hartwig, V.; Frijia, F.

    2012-01-01

    Cardiac metabolism assessment with hyperpolarized 13C magnetic resonance spectroscopy in pig models requires the design of dedicated coils capable of providing large field of view with high signal-to-noise ratio (SNR) data. This work presents a comparison between a commercial 13C quadrature...

  19. Molecular MRI based on hyper-polarized xenon

    International Nuclear Information System (INIS)

    Tassali, Nawal

    2012-01-01

    Magnetic Resonance Imaging (MRI) has a high importance in medicine as it enables the observation of the organs inside the body without the use of radiative or invasive techniques. However it is known to suffer from poor sensitivity. To circumvent this limitation, a key solution resides in the use of hyper-polarized species. Among the entities with which we can drastically increase nuclear polarization, xenon has very specific properties through its interactions with its close environment that lead to a wide chemical shift bandwidth. The goal is thus to use it as a tracer. This PhD thesis focuses on the concept of 129 Xe MRI-based sensors for the detection of biological events. In this approach, hyper-polarized xenon is vectorized to biological targets via functionalized host systems, and then localized thanks to fast dedicated MRI sequences. The conception and set-up of a spin-exchange optical pumping device is first described. Then studies about the interaction of the hyper-polarized noble gas with new cryptophanes susceptible to constitute powerful host molecules are detailed. Also the implementation of recent MRI sequences optimized for the transient character of the hyper-polarization and taking profit of the xenon in-out exchange is described. Applications of this approach for the detection of metallic ions and cellular receptors are studied. Finally, our first in vivo results on a small animal model are presented. (author) [fr

  20. A magnetic tunnel to shelter hyperpolarized fluids

    Energy Technology Data Exchange (ETDEWEB)

    Milani, Jonas, E-mail: jonas.milani@epfl.ch; Vuichoud, Basile; Bornet, Aurélien; Miéville, Pascal; Mottier, Roger [Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime, CH-1015 Lausanne (Switzerland); Jannin, Sami [Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime, CH-1015 Lausanne (Switzerland); Bruker BioSpin AG, Industriestrasse 26, CH-8117 Fällanden (Switzerland); Bodenhausen, Geoffrey [Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), Batochime, CH-1015 Lausanne (Switzerland); Département de Chimie, École Normale Supérieure-PSL Research University, 24 rue Lhomond, F-75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); CNRS, UMR 7203 LBM, F-75005 Paris (France)

    2015-02-15

    To shield solutions carrying hyperpolarized nuclear magnetization from rapid relaxation during transfer through low fields, the transfer duct can be threaded through an array of permanent magnets. The advantages are illustrated for solutions containing hyperpolarized {sup 1}H and {sup 13}C nuclei in a variety of molecules.

  1. A magnetic tunnel to shelter hyperpolarized fluids

    International Nuclear Information System (INIS)

    Milani, Jonas; Vuichoud, Basile; Bornet, Aurélien; Miéville, Pascal; Mottier, Roger; Jannin, Sami; Bodenhausen, Geoffrey

    2015-01-01

    To shield solutions carrying hyperpolarized nuclear magnetization from rapid relaxation during transfer through low fields, the transfer duct can be threaded through an array of permanent magnets. The advantages are illustrated for solutions containing hyperpolarized 1 H and 13 C nuclei in a variety of molecules

  2. Dynamic coronary MR angiography in a pig model with hyperpolarized water

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Hansen, Esben Søvsø Szocska; Tougaard, Rasmus Stilling

    2018-01-01

    To investigate dynamic coronary MR angiography using hyperpolarized water as a positive contrast agent. Hyperpolarization can increase the signal by several orders of magnitude, and has recently been translated to human cardiac application. The aim was to achieve large 1 H signal enhancement...... to allow high-resolution imaging of the coronary arteries. Protons in D2 O were hyperpolarized by dissolution dynamic nuclear polarization. A total of 18 mL of hyperpolarized water was injected into the coronary arteries of healthy pigs (N = 9; 3 injections in 3 animals). The MRI images were acquired...... with a gradient-echo sequence in an oblique slab covering the main left coronary arteries with 0.55 mm in-plane resolution. The acquisition time was 870 ms per frame. A more than 200-fold signal enhancement compared with thermally polarized water at 3 T was obtained. Coronary angiographic images with a signal...

  3. Design of a 15N Molecular Unit to Achieve Long Retention of Hyperpolarized Spin State

    Science.gov (United States)

    Nonaka, Hiroshi; Hirano, Masashi; Imakura, Yuki; Takakusagi, Yoichi; Ichikawa, Kazuhiro; Sando, Shinsuke

    2017-01-01

    Nuclear hyperpolarization is a phenomenon that can be used to improve the sensitivity of magnetic resonance molecular sensors. However, such sensors typically suffer from short hyperpolarization lifetime. Herein we report that [15N, D14]trimethylphenylammonium (TMPA) has a remarkably long spin-lattice relaxation time (1128 s, 14.1 T, 30 °C, D2O) on its 15N nuclei and achieves a long retention of the hyperpolarized state. [15N, D14]TMPA-based hyperpolarized sensor for carboxylesterase allowed the highly sensitive analysis of enzymatic reaction by 15N NMR for over 40 min in phophate-buffered saline (H2O, pH 7.4, 37 °C).

  4. Continuous hyperpolarization with parahydrogen in a membrane reactor

    Science.gov (United States)

    Lehmkuhl, Sören; Wiese, Martin; Schubert, Lukas; Held, Mathias; Küppers, Markus; Wessling, Matthias; Blümich, Bernhard

    2018-06-01

    Hyperpolarization methods entail a high potential to boost the sensitivity of NMR. Even though the "Signal Amplification by Reversible Exchange" (SABRE) approach uses para-enriched hydrogen, p-H2, to repeatedly achieve high polarization levels on target molecules without altering their chemical structure, such studies are often limited to batch experiments in NMR tubes. Alternatively, this work introduces a continuous flow setup including a membrane reactor for the p-H2, supply and consecutive detection in a 1 T NMR spectrometer. Two SABRE substrates pyridine and nicotinamide were hyperpolarized, and more than 1000-fold signal enhancement was found. Our strategy combines low-field NMR spectrometry and a membrane flow reactor. This enables precise control of the experimental conditions such as liquid and gas pressures, and volume flow for ensuring repeatable maximum polarization.

  5. Optical hyperpolarization of 13C nuclear spins in nanodiamond ensembles

    Science.gov (United States)

    Chen, Q.; Schwarz, I.; Jelezko, F.; Retzker, A.; Plenio, M. B.

    2015-11-01

    Dynamical nuclear polarization holds the key for orders of magnitude enhancements of nuclear magnetic resonance signals which, in turn, would enable a wide range of novel applications in biomedical sciences. However, current implementations of DNP require cryogenic temperatures and long times for achieving high polarization. Here we propose and analyze in detail protocols that can achieve rapid hyperpolarization of 13C nuclear spins in randomly oriented ensembles of nanodiamonds at room temperature. Our protocols exploit a combination of optical polarization of electron spins in nitrogen-vacancy centers and the transfer of this polarization to 13C nuclei by means of microwave control to overcome the severe challenges that are posed by the random orientation of the nanodiamonds and their nitrogen-vacancy centers. Specifically, these random orientations result in exceedingly large energy variations of the electron spin levels that render the polarization and coherent control of the nitrogen-vacancy center electron spins as well as the control of their coherent interaction with the surrounding 13C nuclear spins highly inefficient. We address these challenges by a combination of an off-resonant microwave double resonance scheme in conjunction with a realization of the integrated solid effect which, together with adiabatic rotations of external magnetic fields or rotations of nanodiamonds, leads to a protocol that achieves high levels of hyperpolarization of the entire nuclear-spin bath in a randomly oriented ensemble of nanodiamonds even at room temperature. This hyperpolarization together with the long nuclear-spin polarization lifetimes in nanodiamonds and the relatively high density of 13C nuclei has the potential to result in a major signal enhancement in 13C nuclear magnetic resonance imaging and suggests functionalized and hyperpolarized nanodiamonds as a unique probe for molecular imaging both in vitro and in vivo.

  6. Characterization of high concentration dust generator

    International Nuclear Information System (INIS)

    Shimura, Toichiro; Yokochi, Akira

    1999-01-01

    This paper describes the development of fluidized bed type high concentration dust generator that keeps for long period dust concentration range of about 10 mg/m 3 for the study of working place monitoring system and evaluation of respirator. The generator is keeping constant powder in fluidized bed for keeping the dust concentration. It is necessary to keep constant feeding rate of powder in order to keep the quantity of dust in the fluidized bed. Our generator enables to obtain constant feeding rate by a screw feeder and by using mixed powder with fluidising particles (glass beads) before feeding. The generator produces high concentration dust of 11.3 mg/m 3 ± 1.0 mg/m 3 for about 5 hours and keeps the dust size 4.2-4.6 μm in mass median aerodynamic diameter with reasonable reproducibility. (author)

  7. Stress concentration effects in high pressure components

    International Nuclear Information System (INIS)

    Aller, J.E.

    1990-01-01

    This paper examines the stress concentration effects of sideholes in thick walled, high pressure cylinders. It has been shown that the theoretical stress concentration factor at the intersection of a small crossbore in a closed end, thick walled cylinder varies between 3.0 and 4.0. Tests have shown that this effect can be greatly reduced in practice by carefully radiusing the bore intersection and autofrettaging the cylinder. It has also been shown that the minimum stress concentration factor occurs when the main bore and sidehole or crossbore have the same diameter, and the radius of the intersection is approximately equal to the sidehole radius. When the bore and sidehole intersection angle decreases from 90 degrees, the stress concentration factor increases significantly. Knowledge of these fundamental relationships can be used in maintaining, as well ad designing, high pressure equipment

  8. Ion permeabilities in mouse sperm reveal an external trigger for SLO3-dependent hyperpolarization.

    Directory of Open Access Journals (Sweden)

    Julio C Chávez

    Full Text Available Unlike most cells of the body which function in an ionic environment controlled within narrow limits, spermatozoa must function in a less controlled external environment. In order to better understand how sperm control their membrane potential in different ionic conditions, we measured mouse sperm membrane potentials under a variety of conditions and at different external K(+ concentrations, both before and after capacitation. Experiments were undertaken using both wild-type, and mutant mouse sperm from the knock-out strain of the sperm-specific, pH-sensitive, SLO3 K(+ channel. Membrane voltage data were fit to the Goldman-Hodgkin-Katz equation. Our study revealed a significant membrane permeability to both K(+ and Cl(- before capacitation, as well as Na(+. The permeability to both K(+ and Cl(- has the effect of preventing large changes in membrane potential when the extracellular concentration of either ion is changed. Such a mechanism may protect against undesired shifts in membrane potential in changing ionic environments. We found that a significant portion of resting membrane potassium permeability in wild-type sperm was contributed by SLO3 K(+ channels. We also found that further activation of SLO3 channels was the essential mechanism producing membrane hyperpolarization under two separate conditions, 1 elevation of external pH prior to capacitation and 2 capacitating conditions. Both conditions produced a significant membrane hyperpolarization in wild-type which was absent in SLO3 mutant sperm. Hyperpolarization in both conditions may result from activation of SLO3 channels by raising intracellular pH; however, demonstrating that SLO3-dependent hyperpolarization is achieved by an alkaline environment alone shows that SLO3 channel activation might occur independently of other events associated with capacitation. For example sperm may undergo stages of membrane hyperpolarization when reaching alkaline regions of the female genital tract

  9. Studies to enhance the hyperpolarization level in PHIP-SAH-produced C13-pyruvate

    Science.gov (United States)

    Cavallari, Eleonora; Carrera, Carla; Aime, Silvio; Reineri, Francesca

    2018-04-01

    The use of [1-13C]pyruvate, hyperpolarized by dissolution-Dynamic Nuclear Polarization (d-DNP), in in vivo metabolic studies has developed quickly, thanks to the imaging probe's diagnostic relevance. Nevertheless, the cost of a d-DNP polarizer is quite high and the speed of hyperpolarization process is relatively slow, meaning that its use is limited to few research laboratories. ParaHydrogen Induced Polarization Side Arm Hydrogenation (PHIP-SAH) (Reineri et al., 2015) is a cost effective and easy-to-handle method that produces 13C-MR hyperpolarization in [1-13C]pyruvate and other metabolites. This work aims to identify the main determinants of the hyperpolarization levels observed in C13-pyruvate using this method. By dissecting the various steps of the PHIP-SAH procedure, it has been possible to assess the role of several experimental parameters whose optimization must be pursued if this method is to be made suitable for future translational steps. The search for possible solutions has led to improvements in the polarization of sodium [1-13C]pyruvate from 2% to 5%. Moreover, these results suggest that observed polarization levels could be increased considerably by an automatized procedure which would reduce the time required for the work-up passages that are currently carried out manually. The results reported herein mean that the attainment of polarization levels suitable for the metabolic imaging applications of these hyperpolarized substrates show significant promise.

  10. Cellulase Inhibition by High Concentrations of Monosaccharides

    DEFF Research Database (Denmark)

    Hsieh, Chia-Wen; Cannella, David; Jørgensen, Henning

    2014-01-01

    Biological degradation of biomass on an industrial scale culminates in high concentrations of end products. It is known that the accumulation of glucose and cellobiose, end products of hydrolysis, inhibit cellulases and decrease glucose yields. Aside from these end products, however, other monosa...

  11. Metabolic Imaging of Patients with Prostate Cancer Using Hyperpolarized [1-13C]Pyruvate

    Science.gov (United States)

    Nelson, Sarah J.; Kurhanewicz, John; Vigneron, Daniel B.; Larson, Peder E. Z.; Harzstark, Andrea L.; Ferrone, Marcus; van Criekinge, Mark; Chang, Jose W.; Bok, Robert; Park, Ilwoo; Reed, Galen; Carvajal, Lucas; Small, Eric J.; Munster, Pamela; Weinberg, Vivian K.; Ardenkjaer-Larsen, Jan Henrik; Chen, Albert P.; Hurd, Ralph E.; Odegardstuen, Liv-Ingrid; Robb, Fraser J.; Tropp, James; Murray, Jonathan A.

    2014-01-01

    This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-13C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-fold enhancement in signal relative to conventional magnetic resonance (MR) imaging. When combined with the rapid acquisition of in vivo 13C MR data, it is possible to evaluate the distribution of agents such as [1-13C]pyruvate and its metabolic products lactate, alanine, and bicarbonate in a matter of seconds. Preclinical studies in cancer models have detected elevated levels of hyperpolarized [1-13C]lactate in tumor, with the ratio of [1-13C]lactate/[1-13C]pyruvate being increased in high-grade tumors and decreased after successful treatment. Translation of this technology into humans was achieved by modifying the instrument that generates the hyperpolarized agent, constructing specialized radio frequency coils to detect 13C nuclei, and developing new pulse sequences to efficiently capture the signal. The study population comprised patients with biopsy-proven prostate cancer, with 31 subjects being injected with hyperpolarized [1-13C]pyruvate. The median time to deliver the agent was 66 s, and uptake was observed about 20 s after injection. No dose-limiting toxicities were observed, and the highest dose (0.43 ml/kg of 230 mM agent) gave the best signal-to-noise ratio for hyperpolarized [1-13C]pyruvate. The results were extremely promising in not only confirming the safety of the agent but also showing elevated [1-13C]lactate/[1-13C]pyruvate in regions of biopsy-proven cancer. These findings will be valuable for noninvasive cancer diagnosis and treatment monitoring in future clinical trials. PMID:23946197

  12. Genealogical series method. Hyperpolar points screen effect

    International Nuclear Information System (INIS)

    Gorbatov, A.M.

    1991-01-01

    The fundamental values of the genealogical series method -the genealogical integrals (sandwiches) have been investigated. The hyperpolar points screen effect has been found. It allows one to calculate the sandwiches for the Fermion systems with large number of particles and to ascertain the validity of the iterated-potential method as well. For the first time the genealogical-series method has been realized numerically for the central spin-independent potential

  13. Hyperpolarized H2O MR angiography

    DEFF Research Database (Denmark)

    Ardenkjær-Larsen, Jan Henrik; Laustsen, Christoffer; Bowen, Sean

    2014-01-01

    polarization followed by dissolution in D2O. A water 1H signal enhancement of 77 times compared with 4.7 Tesla was obtained. This corresponds to a polarization of 3.5% for the 3.9 mol/L 1H in D2O . Moreover, a T1 in excess of 20 s was achieved. The use of hyperpolarized water as a contrast agent presents a new...

  14. Mechanisms of astrocytic K(+) clearance and swelling under high extracellular K(+) concentrations.

    Science.gov (United States)

    Murakami, Shingo; Kurachi, Yoshihisa

    2016-03-01

    In response to the elevation of extracellular K(+) concentration ([K(+)]out), astrocytes clear excessive K(+) to maintain conditions necessary for neural activity. K(+) clearance in astrocytes occurs via two processes: K(+) uptake and K(+) spatial buffering. High [K(+)]out also induces swelling in astrocytes, leading to edema and cell death in the brain. Despite the importance of astrocytic K(+) clearance and swelling, the underlying mechanisms remain unclear. Here, we report results from a simulation analysis of astrocytic K(+) clearance and swelling. Astrocyte models were constructed by incorporating various mechanisms such as intra/extracellular ion concentrations of Na(+), K(+), and Cl(-), cell volume, and models of Na,K-ATPase, Na-K-Cl cotransporter (NKCC), K-Cl cotransporter, inwardly-rectifying K(+) (KIR) channel, passive Cl(-) current, and aquaporin channel. The simulated response of astrocyte models under the uniform distribution of high [K(+)]out revealed significant contributions of NKCC and Na,K-ATPase to increases of intracellular K(+) and Cl(-) concentrations, and swelling. Moreover, we found that, under the non-uniform distribution of high [K(+)]out, KIR channels localized at synaptic clefts absorbed excess K(+) by depolarizing the equivalent potential of K(+) (E K) above membrane potential, while K(+) released through perivascular KIR channels was enhanced by hyperpolarizing E K and depolarizing membrane potential. Further analysis of simulated drug effects revealed that astrocyte swelling was modulated by blocking each of the ion channels and transporters. Our simulation analysis revealed controversial mechanisms of astrocytic K(+) clearance and swelling resulting from complex interactions among ion channels and transporters.

  15. Analysis of Cancer Metabolism by Imaging Hyperpolarized Nuclei: Prospects for Translation to Clinical Research

    Directory of Open Access Journals (Sweden)

    John Kurhanewicz

    2011-02-01

    Full Text Available A major challenge in cancer biology is to monitor and understand cancer metabolism in vivo with the goal of improved diagnosis and perhaps therapy. Because of the complexity of biochemical pathways, tracer methods are required for detecting specific enzyme-catalyzed reactions. Stable isotopes such as 13C or 15N with detection by nuclear magnetic resonance provide the necessary information about tissue biochemistry, but the crucial metabolites are present in low concentration and therefore are beyond the detection threshold of traditional magnetic resonance methods. A solution is to improve sensitivity by a factor of 10,000 or more by temporarily redistributing the populations of nuclear spins in a magnetic field, a process termed hyperpolarization. Although this effect is short-lived, hyperpolarized molecules can be generated in an aqueous solution and infused in vivo where metabolism generates products that can be imaged. This discovery lifts the primary constraint on magnetic resonance imaging for monitoring metabolism—poor sensitivity—while preserving the advantage of biochemical information. The purpose of this report was to briefly summarize the known abnormalities in cancer metabolism, the value and limitations of current imaging methods for metabolism, and the principles of hyperpolarization. Recent preclinical applications are described. Hyperpolarization technology is still in its infancy, and current polarizer equipment and methods are suboptimal. Nevertheless, there are no fundamental barriers to rapid translation of this exciting technology to clinical research and perhaps clinical care.

  16. High altitude may alter oxygen availability and renal metabolism in diabetics as measured by hyperpolarized [1-1C]pyruvate magnetic resonance imaging

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Lycke, Sara; Palm, Fredrik

    2014-01-01

    inspired oxygen did not alter renal metabolism in the control group. Reduced oxygen availability in the diabetic kidney altered energy metabolism by increasing lactate and alanine formation by 23% and 34%, respectively, whereas the bicarbonate flux was unchanged. Thus, the increased prevalence and severity......The kidneys account for about 10% of the whole body oxygen consumption, whereas only 0.5% of the total body mass. It is known that intrarenal hypoxia is present in several diseases associated with development of kidney disease, including diabetes, and when renal blood flow is unaffected....... The importance of deranged oxygen metabolism is further supported by deterioration of kidney function in patients with diabetes living at high altitude. Thus, we argue that reduced oxygen availability alters renal energy metabolism. Here, we introduce a novel magnetic resonance imaging (MRI) approach to monitor...

  17. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  18. Renal MR angiography and perfusion in the pig using hyperpolarized water.

    Science.gov (United States)

    Wigh Lipsø, Kasper; Hansen, Esben Søvsø Szocska; Tougaard, Rasmus Stilling; Laustsen, Christoffer; Ardenkjaer-Larsen, Jan Henrik

    2017-09-01

    To study hyperpolarized water as an angiography and perfusion tracer in a large animal model. Protons dissolved in deuterium oxide (D 2 O) were hyperpolarized in a SPINlab dissolution dynamic nuclear polarization (dDNP) polarizer and subsequently investigated in vivo in a pig model at 3 Tesla (T). Approximately 15 mL of hyperpolarized water was injected in the renal artery by hand over 4-5 s. A liquid state polarization of 5.3 ± 0.9% of 3.8 M protons in 15 mL of deuterium oxide was achieved with a T 1 of 24 ± 1 s. This allowed injection through an arterial catheter into the renal artery and subsequently high-contrast imaging of the entire kidney parenchyma over several seconds. The dynamic images allow quantification of tissue perfusion, with a mean cortical perfusion of 504 ± 123 mL/100 mL/min. Hyperpolarized water MR imaging was successfully demonstrated as a renal angiography and perfusion method. Quantitative perfusion maps of the kidney were obtained in agreement with literature and control experiments with gadolinium contrast. Magn Reson Med 78:1131-1135, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  19. Nanodiamond-enhanced MRI via in situ hyperpolarization

    Science.gov (United States)

    Waddington, David E. J.; Sarracanie, Mathieu; Zhang, Huiliang; Salameh, Najat; Glenn, David R.; Rej, Ewa; Gaebel, Torsten; Boele, Thomas; Walsworth, Ronald L.; Reilly, David J.; Rosen, Matthew S.

    2017-04-01

    Nanodiamonds are of interest as nontoxic substrates for targeted drug delivery and as highly biostable fluorescent markers for cellular tracking. Beyond optical techniques, however, options for noninvasive imaging of nanodiamonds in vivo are severely limited. Here, we demonstrate that the Overhauser effect, a proton-electron polarization transfer technique, can enable high-contrast magnetic resonance imaging (MRI) of nanodiamonds in water at room temperature and ultra-low magnetic field. The technique transfers spin polarization from paramagnetic impurities at nanodiamond surfaces to 1H spins in the surrounding water solution, creating MRI contrast on-demand. We examine the conditions required for maximum enhancement as well as the ultimate sensitivity of the technique. The ability to perform continuous in situ hyperpolarization via the Overhauser mechanism, in combination with the excellent in vivo stability of nanodiamond, raises the possibility of performing noninvasive in vivo tracking of nanodiamond over indefinitely long periods of time.

  20. Probing cardiac metabolism by hyperpolarized 13C MR using an exclusively endogenous substrate mixture and photo-induced nonpersistent radicals

    DEFF Research Database (Denmark)

    Bastiaansen, Jessica A M; Yoshihara, Hikari A I; Capozzi, Andrea

    2018-01-01

    dissolved, and the radical-free hyperpolarized solution was rapidly transferred into an injection pump located inside a 9.4T scanner. The hyperpolarized solution was injected in healthy rats to measure cardiac metabolism in vivo. Ultraviolet irradiation created nonpersistent radicals in a mixture containing......To probe the cardiac metabolism of carbohydrates and short chain fatty acids simultaneously in vivo following the injection of a hyperpolarized 13 C-labeled substrate mixture prepared using photo-induced nonpersistent radicals. Droplets of mixed [1-13 C]pyruvic and [1-13 C]butyric acids were frozen...... into glassy beads in liquid nitrogen. Ethanol addition was investigated as a means to increase the polarization level. The beads were irradiated with ultraviolet light and the radical concentration was measured by ESR spectroscopy. Following dynamic nuclear polarization in a 7T polarizer, the beads were...

  1. High-efficiency concentrator silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. (Stanford Univ., CA (USA). Solid-State Electronics Lab.)

    1990-11-01

    This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm{sup 2} cell with front grids achieved 26% efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

  2. Characterization of Chemical Exchange Using Relaxation Dispersion of Hyperpolarized Nuclear Spins.

    Science.gov (United States)

    Liu, Mengxiao; Kim, Yaewon; Hilty, Christian

    2017-09-05

    Chemical exchange phenomena are ubiquitous in macromolecules, which undergo conformational change or ligand complexation. NMR relaxation dispersion (RD) spectroscopy based on a Carr-Purcell-Meiboom-Gill pulse sequence is widely applied to identify the exchange and measure the lifetime of intermediate states on the millisecond time scale. Advances in hyperpolarization methods improve the applicability of NMR spectroscopy when rapid acquisitions or low concentrations are required, through an increase in signal strength by several orders of magnitude. Here, we demonstrate the measurement of chemical exchange from a single aliquot of a ligand hyperpolarized by dissolution dynamic nuclear polarization (D-DNP). Transverse relaxation rates are measured simultaneously at different pulsing delays by dual-channel 19 F NMR spectroscopy. This two-point measurement is shown to allow the determination of the exchange term in the relaxation rate expression. For the ligand 4-(trifluoromethyl)benzene-1-carboximidamide binding to the protein trypsin, the exchange term is found to be equal within error limits in neutral and acidic environments from D-DNP NMR spectroscopy, corresponding to a pre-equilibrium of trypsin deprotonation. This finding illustrates the capability for determination of binding mechanisms using D-DNP RD. Taking advantage of hyperpolarization, the ligand concentration in the exchange measurements can reach on the order of tens of μM and protein concentration can be below 1 μM, i.e., conditions typically accessible in drug discovery.

  3. New insights into lung diseases using hyperpolarized gas MRI.

    Science.gov (United States)

    Flors, L; Altes, T A; Mugler, J P; de Lange, E E; Miller, G W; Mata, J F; Ruset, I C; Hersman, F W

    2015-01-01

    Hyperpolarized (HP) gases are a new class of contrast agents that permit to obtain high temporal and spatial resolution magnetic resonance images (MRI) of the lung airspaces. HP gas MRI has become important research tool not only for morphological and functional evaluation of normal pulmonary physiology but also for regional quantification of pathologic changes occurring in several lung diseases. The purpose of this work is to provide an introduction to MRI using HP noble gases, describing both the basic principles of the technique and the new information about lung disease provided by clinical studies with this method. The applications of the technique in normal subjects, smoking related lung disease, asthma, and cystic fibrosis are reviewed. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  4. High-flux solar concentration with imaging designs

    Energy Technology Data Exchange (ETDEWEB)

    Feuermann, D. [Ben-Gurion University of the Negev (Israel). Jacob Blaustein Institute for Desert Research; Gordon, J.M. [Ben-Gurion University of the Negev (Israel). Jacob Blaustein Institute for Desert Research; Ben-Gurion University of the Negev (Israel). Dept. of Mechanical Engineering; Ries, H. [Ries and Partners, Munich (Germany)

    1999-02-01

    Most large solar concentrators designed for high flux concentration at high collection efficiency are based on imaging primary mirrors and nonimaging secondary concentrators. In this paper, we offer an alternative purely imaging two-stage solar concentrator that can attain high flux concentration at high collection efficiency. Possible practical virtues include: (1) an inherent large gap between absorber and secondary mirror; (2) a restricted angular range on the absorber; and (3) an upward-facing receiver where collected energy can be extracted via the (shaded) apex of the parabola. We use efficiency-concentration plots to characterize the solar concentrators considered, and to evaluate the potential improvements with secondary concentrators. (author)

  5. Horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications.

    Science.gov (United States)

    Ma, Hongcai; Wu, Lin

    2015-07-10

    We present the design of a horizontally staggered lightguide solar concentrator with lateral displacement tracking for high concentration applications. This solar concentrator consists of an array of telecentric primary concentrators, a horizontally staggered lightguide layer, and a vertically tapered lightguide layer. The primary concentrator is realized by two plano-aspheric lenses with lateral movement and maintains a high F-number over an angle range of ±23.5°. The results of the simulations show that the solar concentrator achieves a high concentration ratio of 500× with ±0.5° of acceptance angle by a single-axis tracker and dual lateral translation stages.

  6. Cementification for radioactive waste including high-concentration sodium sulfate and high-concentration radioactive nuclide

    International Nuclear Information System (INIS)

    Miyamoto, Shinya; Sato, Tatsuaki; Sasoh, Michitaka; Sakurai, Jiro; Takada, Takao

    2005-01-01

    For the cementification of radioactive waste that has large concentrations of sodium sulfate and radioactive nuclide, a way of fixation for sulfate ion was studied comprising the pH control of water in contact with the cement solid, and the removal of the excess water from the cement matrix to prevent hydrogen gas generation with radiolysis. It was confirmed that the sulfate ion concentration in the contacted water with the cement solid is decreased with the formation of ettringite or barium sulfate before solidification, the pH value of the pore water in the cement solid can control less than 12.5 by the application of zeolite and a low-alkali cement such as alumina cement or fly ash mixed cement, and removal of the excess water from the cement matrix by heating is possible with aggregate addition. Consequently, radioactive waste including high-concentration sodium sulfate and high-concentration radioactive nuclide can be solidified with cementitious materials. (author)

  7. Cryogenics free production of hyperpolarized 129Xe and 83Kr for biomedical MRI applications

    Science.gov (United States)

    Hughes-Riley, Theodore; Six, Joseph S.; Lilburn, David M. L.; Stupic, Karl F.; Dorkes, Alan C.; Shaw, Dominick E.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2013-12-01

    As an alternative to cryogenic gas handling, hyperpolarized (hp) gas mixtures were extracted directly from the spin exchange optical pumping (SEOP) process through expansion followed by compression to ambient pressure for biomedical MRI applications. The omission of cryogenic gas separation generally requires the usage of high xenon or krypton concentrations at low SEOP gas pressures to generate hp 129Xe or hp 83Kr with sufficient MR signal intensity for imaging applications. Two different extraction schemes for the hp gasses were explored with focus on the preservation of the nuclear spin polarization. It was found that an extraction scheme based on an inflatable, pressure controlled balloon is sufficient for hp 129Xe handling, while 83Kr can efficiently be extracted through a single cycle piston pump. The extraction methods were tested for ex vivo MRI applications with excised rat lungs. Precise mixing of the hp gases with oxygen, which may be of interest for potential in vivo applications, was accomplished during the extraction process using a piston pump. The 83Kr bulk gas phase T1 relaxation in the mixtures containing more than approximately 1% O2 was found to be slower than that of 129Xe in corresponding mixtures. The experimental setup also facilitated 129Xe T1 relaxation measurements as a function of O2 concentration within excised lungs.

  8. Cryogenics free production of hyperpolarized 129Xe and 83Kr for biomedical MRI applications☆

    Science.gov (United States)

    Hughes-Riley, Theodore; Six, Joseph S.; Lilburn, David M.L.; Stupic, Karl F.; Dorkes, Alan C.; Shaw, Dominick E.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2013-01-01

    As an alternative to cryogenic gas handling, hyperpolarized (hp) gas mixtures were extracted directly from the spin exchange optical pumping (SEOP) process through expansion followed by compression to ambient pressure for biomedical MRI applications. The omission of cryogenic gas separation generally requires the usage of high xenon or krypton concentrations at low SEOP gas pressures to generate hp 129Xe or hp 83Kr with sufficient MR signal intensity for imaging applications. Two different extraction schemes for the hp gasses were explored with focus on the preservation of the nuclear spin polarization. It was found that an extraction scheme based on an inflatable, pressure controlled balloon is sufficient for hp 129Xe handling, while 83Kr can efficiently be extracted through a single cycle piston pump. The extraction methods were tested for ex vivo MRI applications with excised rat lungs. Precise mixing of the hp gases with oxygen, which may be of interest for potential in vivo applications, was accomplished during the extraction process using a piston pump. The 83Kr bulk gas phase T1 relaxation in the mixtures containing more than approximately 1% O2 was found to be slower than that of 129Xe in corresponding mixtures. The experimental setup also facilitated 129Xe T1 relaxation measurements as a function of O2 concentration within excised lungs. PMID:24135800

  9. NMR study of hyper-polarized 129Xe and applications to liquid-phase NMR experiments

    International Nuclear Information System (INIS)

    Marion, D.

    2008-07-01

    In liquid samples where both nuclear polarization and spin density are strong, the magnetization dynamics, which can be analysed by NMR (nuclear magnetic resonance) methods, is deeply influenced by the internal couplings induced by local dipolar fields. The present thesis describes some of the many consequences associated to the presence in the sample of concentrated xenon hyper-polarized by an optical pumping process. First, we deal with the induced modifications in frequency and line width of the proton and xenon spectra, then we present the results of SPIDER, a coherent polarization transfer experiment designed to enhance the polarization of protons, in order to increase their NMR signal level. A third part is dedicated to the description of the apparition of repeated chaotic maser emissions by un unstable xenon magnetization coupled to the detection coil tuned at the xenon Larmor frequency (here 138 MHz). In the last part, we present a new method allowing a better tuning of any NMR detection probe and resulting in sensible gains in terms of sensitivity and signal shaping. Finally, we conclude with a partial questioning of the classical relaxation theory in the specific field of highly polarized and concentrated spin systems in a liquid phase. (author)

  10. Hyperpolarized nanodiamond with long spin-relaxation times

    Science.gov (United States)

    Rej, Ewa; Gaebel, Torsten; Boele, Thomas; Waddington, David E. J.; Reilly, David J.

    2015-10-01

    The use of hyperpolarized agents in magnetic resonance, such as 13C-labelled compounds, enables powerful new imaging and detection modalities that stem from a 10,000-fold boost in signal. A major challenge for the future of the hyperpolarization technique is the inherently short spin-relaxation times, typically nanodiamond can be hyperpolarized at cryogenic and room temperature without the use of free radicals, and, owing to their solid-state environment, exhibit relaxation times exceeding 1 h. Combined with the already established applications of nanodiamonds in the life sciences as inexpensive fluorescent markers and non-cytotoxic substrates for gene and drug delivery, these results extend the theranostic capabilities of nanoscale diamonds into the domain of hyperpolarized magnetic resonance.

  11. Transmit-Only/Receive-Only Radiofrequency System for Hyperpolarized 13C MRS Cardiac Metabolism Studies in Pigs

    DEFF Research Database (Denmark)

    Giovannetti, G.; Frijia, F.; Hartwig, V.

    2013-01-01

    Hyperpolarized 13C magnetic resonance spectroscopy in pig models enables metabolic activity mapping, providing a powerful tool for the study of the heart physiology, but requires the development of dedicated radiofrequency coils, capable of providing large field of view with high signal......-to-noise ratio (SNR) data. This work describes the simulations and the tests of a transmit-only (TX) volume coil/receive-only (RX) surface coil both designed for hyperpolarized studies of pig heart with a clinical 3T scanner. The coil characterization is performed by developing an SNR model for coil performance...

  12. 3D Hyperpolarized C-13 EPI with Calibrationless Parallel Imaging

    DEFF Research Database (Denmark)

    Gordon, Jeremy W.; Hansen, Rie Beck; Shin, Peter J.

    2018-01-01

    With the translation of metabolic MRI with hyperpolarized 13C agents into the clinic, imaging approaches will require large volumetric FOVs to support clinical applications. Parallel imaging techniques will be crucial to increasing volumetric scan coverage while minimizing RF requirements and tem...... strategies to accelerate and undersample hyperpolarized 13C data using 3D blipped EPI acquisitions and multichannel receive coils, and demonstrated its application in a human study of [1-13C]pyruvate metabolism....

  13. Hyperpolarized 13C MR imaging detects no lactate production in mutant IDH1 gliomas: Implications for diagnosis and response monitoring

    Directory of Open Access Journals (Sweden)

    Myriam M. Chaumeil

    2016-01-01

    Full Text Available Metabolic imaging of brain tumors using 13C Magnetic Resonance Spectroscopy (MRS of hyperpolarized [1-13C] pyruvate is a promising neuroimaging strategy which, after a decade of preclinical success in glioblastoma (GBM models, is now entering clinical trials in multiple centers. Typically, the presence of GBM has been associated with elevated hyperpolarized [1-13C] lactate produced from [1-13C] pyruvate, and response to therapy has been associated with a drop in hyperpolarized [1-13C] lactate. However, to date, lower grade gliomas had not been investigated using this approach. The most prevalent mutation in lower grade gliomas is the isocitrate dehydrogenase 1 (IDH1 mutation, which, in addition to initiating tumor development, also induces metabolic reprogramming. In particular, mutant IDH1 gliomas are associated with low levels of lactate dehydrogenase A (LDHA and monocarboxylate transporters 1 and 4 (MCT1, MCT4, three proteins involved in pyruvate metabolism to lactate. We therefore investigated the potential of 13C MRS of hyperpolarized [1-13C] pyruvate for detection of mutant IDH1 gliomas and for monitoring of their therapeutic response. We studied patient-derived mutant IDH1 glioma cells that underexpress LDHA, MCT1 and MCT4, and wild-type IDH1 GBM cells that express high levels of these proteins. Mutant IDH1 cells and tumors produced significantly less hyperpolarized [1-13C] lactate compared to GBM, consistent with their metabolic reprogramming. Furthermore, hyperpolarized [1-13C] lactate production was not affected by chemotherapeutic treatment with temozolomide (TMZ in mutant IDH1 tumors, in contrast to previous reports in GBM. Our results demonstrate the unusual metabolic imaging profile of mutant IDH1 gliomas, which, when combined with other clinically available imaging methods, could be used to detect the presence of the IDH1 mutation in vivo.

  14. Hyperpolarized Amino Acid Derivatives as Multivalent Magnetic Resonance pH Sensor Molecules.

    Science.gov (United States)

    Hundshammer, Christian; Düwel, Stephan; Ruseckas, David; Topping, Geoffrey; Dzien, Piotr; Müller, Christoph; Feuerecker, Benedikt; Hövener, Jan B; Haase, Axel; Schwaiger, Markus; Glaser, Steffen J; Schilling, Franz

    2018-02-15

    pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP) magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (p K a ). Proteinogenic amino acids are biocompatible, can be hyperpolarized and have at least two pH sensitive moieties. However, they do not exhibit a pH sensitivity in the physiologically relevant pH range. Here, we developed a systematic approach to tailor the p K a of molecules using modifications of carbon chain length and derivatization rendering these molecules interesting for pH biosensing. Notably, we identified several derivatives such as [1- 13 C]serine amide and [1- 13 C]-2,3-diaminopropionic acid as novel pH sensors. They bear several spin-1/2 nuclei ( 13 C, 15 N, 31 P) with high sensitivity up to 4.8 ppm/pH and we show that 13 C spins can be hyperpolarized with dissolution dynamic polarization (DNP). Our findings elucidate the molecular mechanisms of chemical shift pH sensors that might help to design tailored probes for specific pH in vivo imaging applications.

  15. Biochemical and structural analysis of the hyperpolarization-activated K(+) channel MVP.

    Science.gov (United States)

    Randich, Amelia M; Cuello, Luis G; Wanderling, Sherry S; Perozo, Eduardo

    2014-03-18

    In contrast to the majority of voltage-gated ion channels, hyperpolarization-activated channels remain closed at depolarizing potentials and are activated at hyperpolarizing potentials. The basis for this reverse polarity is thought to be a result of differences in the way the voltage-sensing domain (VSD) couples to the pore domain. In the absence of structural data, the molecular mechanism of this reverse polarity coupling remains poorly characterized. Here we report the characterization of the structure and local dynamics of the closed activation gate (lower S6 region) of MVP, a hyperpolarization-activated potassium channel from Methanococcus jannaschii, by electron paramagnetic resonance (EPR) spectroscopy. We show that a codon-optimized version of MVP has high expression levels in Escherichia coli, is purified as a stable tetramer, and exhibits expected voltage-dependent activity when reconstituted in liposomes. EPR analysis of the mid to lower S6 region revealed positions exhibiting strong spin-spin coupling, indicating that the activation gate of MVP is closed at 0 mV. A comparison of local environmental parameters along the activation gate for MVP and KcsA indicates that MVP adopts a different closed conformation. These structural details set the stage for future evaluations of reverse electromechanical coupling in MVP.

  16. Biochemical and Structural Analysis of the Hyperpolarization-Activated K+ Channel MVP

    Science.gov (United States)

    2015-01-01

    In contrast to the majority of voltage-gated ion channels, hyperpolarization-activated channels remain closed at depolarizing potentials and are activated at hyperpolarizing potentials. The basis for this reverse polarity is thought to be a result of differences in the way the voltage-sensing domain (VSD) couples to the pore domain. In the absence of structural data, the molecular mechanism of this reverse polarity coupling remains poorly characterized. Here we report the characterization of the structure and local dynamics of the closed activation gate (lower S6 region) of MVP, a hyperpolarization-activated potassium channel from Methanococcus jannaschii, by electron paramagnetic resonance (EPR) spectroscopy. We show that a codon-optimized version of MVP has high expression levels in Escherichia coli, is purified as a stable tetramer, and exhibits expected voltage-dependent activity when reconstituted in liposomes. EPR analysis of the mid to lower S6 region revealed positions exhibiting strong spin–spin coupling, indicating that the activation gate of MVP is closed at 0 mV. A comparison of local environmental parameters along the activation gate for MVP and KcsA indicates that MVP adopts a different closed conformation. These structural details set the stage for future evaluations of reverse electromechanical coupling in MVP. PMID:24490868

  17. Imaging Human Brain Perfusion with Inhaled Hyperpolarized 129Xe MR Imaging.

    Science.gov (United States)

    Rao, Madhwesha R; Stewart, Neil J; Griffiths, Paul D; Norquay, Graham; Wild, Jim M

    2018-02-01

    Purpose To evaluate the feasibility of directly imaging perfusion of human brain tissue by using magnetic resonance (MR) imaging with inhaled hyperpolarized xenon 129 ( 129 Xe). Materials and Methods In vivo imaging with 129 Xe was performed in three healthy participants. The combination of a high-yield spin-exchange optical pumping 129 Xe polarizer, custom-built radiofrequency coils, and an optimized gradient-echo MR imaging protocol was used to achieve signal sensitivity sufficient to directly image hyperpolarized 129 Xe dissolved in the human brain. Conventional T1-weighted proton (hydrogen 1 [ 1 H]) images and perfusion images by using arterial spin labeling were obtained for comparison. Results Images of 129 Xe uptake were obtained with a signal-to-noise ratio of 31 ± 9 and demonstrated structural similarities to the gray matter distribution on conventional T1-weighted 1 H images and to perfusion images from arterial spin labeling. Conclusion Hyperpolarized 129 Xe MR imaging is an injection-free means of imaging the perfusion of cerebral tissue. The proposed method images the uptake of inhaled xenon gas to the extravascular brain tissue compartment across the intact blood-brain barrier. This level of sensitivity is not readily available with contemporary MR imaging methods. © RSNA, 2017.

  18. A Bacterial Toxin with Analgesic Properties: Hyperpolarization of DRG Neurons by Mycolactone.

    Science.gov (United States)

    Song, Ok-Ryul; Kim, Han-Byul; Jouny, Samuel; Ricard, Isabelle; Vandeputte, Alexandre; Deboosere, Nathalie; Marion, Estelle; Queval, Christophe J; Lesport, Pierre; Bourinet, Emmanuel; Henrion, Daniel; Oh, Seog Bae; Lebon, Guillaume; Sandoz, Guillaume; Yeramian, Edouard; Marsollier, Laurent; Brodin, Priscille

    2017-07-18

    Mycolactone, a polyketide molecule produced by Mycobacterium ulcerans , is the etiological agent of Buruli ulcer. This lipid toxin is endowed with pleiotropic effects, presents cytotoxic effects at high doses, and notably plays a pivotal role in host response upon colonization by the bacillus. Most remarkably, mycolactone displays intriguing analgesic capabilities: the toxin suppresses or alleviates the pain of the skin lesions it inflicts. We demonstrated that the analgesic capability of mycolactone was not attributable to nerve damage, but instead resulted from the triggering of a cellular pathway targeting AT₂ receptors (angiotensin II type 2 receptors; AT₂R), and leading to potassium-dependent hyperpolarization. This demonstration paves the way to new nature-inspired analgesic protocols. In this direction, we assess here the hyperpolarizing properties of mycolactone on nociceptive neurons. We developed a dedicated medium-throughput assay based on membrane potential changes, and visualized by confocal microscopy of bis-oxonol-loaded Dorsal Root Ganglion (DRG) neurons. We demonstrate that mycolactone at non-cytotoxic doses triggers the hyperpolarization of DRG neurons through AT₂R, with this action being not affected by known ligands of AT₂R. This result points towards novel AT₂R-dependent signaling pathways in DRG neurons underlying the analgesic effect of mycolactone, with the perspective for the development of new types of nature-inspired analgesics.

  19. Echo-planar MR imaging of dissolved hyperpolarized 129Xe. Potential for M angiography

    International Nuclear Information System (INIS)

    Maansson, S.

    2002-01-01

    Purpose: The feasibility of hyperpolarized 129 Xe for fast MR angiography (MRA) was evaluated using the echo-planar imaging (EPI) technique. Material and Methods: Hyperpolarized Xe gas was dissolved in ethanol; a carrier agent with high solubility for Xe (Ostwald solubility coefficient 2.5) and long relaxation times. The dissolved Xe was injected as a bolus into a flow phantom where the mean flow velocity was 15 cm/s. Ultrafast EPI images with 44 ms scan time were acquired of the flowing bolus and the signal-to-noise ratios (SNR) were measured. Results: The relaxation times of hyperpolarized Xe in ethanol were measured to T1=160±11 s and T2 ≅ 20 s. The resulting images of the flowing liquid were of reasonable quality and had an SNR of about 70. Conclusion: Based on the SNR of the obtained Xe EPI images; it was estimated that rapid in vivo MRA with 129 Xe may be feasible; provided that an efficient; biologically acceptable carrier for Xe can be found and polarization levels of more than 25% can be achieved in isotopically enriched 129 Xe

  20. Magnetic resonance butterfly coils: Design and application for hyperpolarized 13C studies

    DEFF Research Database (Denmark)

    Giovannetti, Giulio; Frijia, Francesca; Attanasio, Simona

    2013-01-01

    Hyperpolarized 13C magnetic resonance spectroscopy in pig models enables cardiac metabolism assessment and provides a powerful tool for heart physiology studies, although the low molar concentration of derivate metabolites gives rise to technological limitations in terms of data quality. The desi...... throughout the volume of interest for cardiac imaging in pig. Experimental SNR-vs-depth profiles, extracted from the [1-13C]acetate phantom chemical shift image (CSI), permitted to highlight the performance of the proposed coils configuration. © 2013 Elsevier Ltd. All rights reserved....

  1. Detection of tobacco smoke deposition by hyperpolarized krypton-83 MRI.

    Science.gov (United States)

    Cleveland, Zackary I; Pavlovskaya, Galina E; Stupic, Karl F; Wooten, Jan B; Repine, John E; Meersmann, Thomas

    2008-02-01

    Despite the importance of the tobacco smoke particulate matter in the lungs to the etiology of pulmonary disease in cigarette smokers, little is currently known about the spatial distribution of particle deposition or the persistence of the resulting deposits in humans, and no satisfactory technique currently exists to directly observe tobacco smoke condensate in airways. In this proof-of-principle work, hyperpolarized (hp) 83Kr MRI and NMR spectroscopy are introduced as probes for tobacco smoke deposition in porous media. A reduction in the hp-83Kr longitudinal (T1) relaxation of up to 95% under near-ambient humidity, pressure and temperature conditions was observed when the krypton gas was brought into contact with surfaces that had been exposed to cigarette smoke. This smoke-induced acceleration of the 83Kr self-relaxation was observed for model glass surfaces that, in some experiments, were coated with bovine lung surfactant extract. However, a similar effect was not observed with hp-(129)Xe indicating that the 83Kr sensitivity to smoke deposition was not caused by paramagnetic species but rather by quadrupolar relaxation due to high adsorption affinity for the smoke deposits. The 83Kr T1 differences between smoke-treated and untreated surfaces were sufficient to produce a strong contrast in variable flip angle FLASH hp-83Kr MRI, suggesting that hp-83Kr may be a promising contrast agent for in vivo pulmonary MRI.

  2. Multijunction Photovoltaic Technologies for High-Performance Concentrators: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, R.; Symko-Davies, M.

    2006-05-01

    Multijunction solar cells provide high-performance technology pathways leading to potentially low-cost electricity generated from concentrated sunlight. The National Center for Photovoltaics at the National Renewable Energy Laboratory has funded different III-V multijunction solar cell technologies and various solar concentration approaches. Within this group of projects, III-V solar cell efficiencies of 41% are close at hand and will likely be reported in these conference proceedings. Companies with well-developed solar concentrator structures foresee installed system costs of $3/watt--half of today's costs--within the next 2 to 5 years as these high-efficiency photovoltaic technologies are incorporated into their concentrator photovoltaic systems. These technology improvements are timely as new large-scale multi-megawatt markets, appropriate for high performance PV concentrators, open around the world.

  3. T1 nuclear magnetic relaxation dispersion of hyperpolarized sodium and cesium hydrogencarbonate-13 C.

    Science.gov (United States)

    Martínez-Santiesteban, Francisco M; Dang, Thien Phuoc; Lim, Heeseung; Chen, Albert P; Scholl, Timothy J

    2017-09-01

    In vivo pH mapping in tissue using hyperpolarized hydrogencarbonate- 13 C has been proposed as a method to study tumor growth and treatment and other pathological conditions related to pH changes. The finite spin-lattice relaxation times (T 1 ) of hyperpolarized media are a significant limiting factor for in vivo imaging. Relaxation times can be measured at standard magnetic fields (1.5 T, 3.0 T etc.), but no such data are available at low fields, where T 1 values can be significantly shorter. This information is required to determine the potential loss of polarization as the agent is dispensed and transported from the polarizer to the MRI scanner. The purpose of this study is to measure T 1 dispersion from low to clinical magnetic fields (0.4 mT to 3.0 T) of different hyperpolarized hydrogencarbonate formulations previously proposed in the literature for in vivo pH measurements. 13 C-enriched cesium and sodium hydrogencarbonate preparations were hyperpolarized using dynamic nuclear polarization, and the T 1 values of different samples were measured at different magnetic field strengths using a fast field-cycling relaxometer and a 3.0 T clinical MRI system. The effects of deuterium oxide as a dissolution medium for sodium hydrogencarbonate were also analyzed. This study finds that the cesium formulation has slightly shorter T 1 values compared with the sodium preparation. However, the higher solubility of cesium hydrogencarbonate- 13 C means it can be polarized at greater concentration, using less trityl radical than sodium hydrogencarbonate- 13 C. This study also establishes that the preparation and handling of sodium hydrogencarbonate formulations in relation to cesium hydrogencarbonate is more difficult, due to the higher viscosity and lower achievable concentrations, and that deuterium oxide significantly increases the T 1 of sodium hydrogencarbonate solutions. Finally, this work also investigates the influence of pH on the spin-lattice relaxation of cesium

  4. Applications of nonimaging optics for very high solar concentrations

    International Nuclear Information System (INIS)

    O'Gallagher, J.; Winston, R.

    1997-01-01

    Using the principles and techniques of nonimaging optics, solar concentrations that approach the theoretical maximum can be achieved. This has applications in solar energy collection wherever concentration is desired. In this paper, we survey recent progress in attaining and using high and ultrahigh solar fluxes. We review a number of potential applications for highly concentrated solar energy and the current status of the associated technology. By making possible new and unique applications for intense solar flux, these techniques have opened a whole new frontier for research and development of potentially economic uses of solar energy

  5. Hyperpolarized 13C MR Markers of Renal Tumor Aggressiveness

    Science.gov (United States)

    2015-12-01

    production in the presence of oxygen (11, 12). Increased glycolysis facilitates the uptake and incorporation of nutrients and biomass needed for cell... shell coil; (d) Hyperpolarized lactate images overlaid on T2 weighted anatomical images, clearly depicting the tumor voxels (Figure 5). As shown in

  6. Fluconazole treatment hyperpolarizes the plasma membrane of Candida cells

    Czech Academy of Sciences Publication Activity Database

    Elicharová, Hana; Sychrová, Hana

    2013-01-01

    Roč. 51, č. 8 (2013), s. 785-798 ISSN 1369-3786 R&D Projects: GA ČR GAP302/12/1151 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : drug resistance * fluconazol * yeast * hyperpolarization Subject RIV: EE - Microbiology, Virology Impact factor: 2.261, year: 2013

  7. Hyperpolarized 2-oxoglutarate as metabolic agent in mr

    DEFF Research Database (Denmark)

    2015-01-01

    Hyperpolarized 1-13C-2-oxoglutarate as contrast agent in13C Magnetic Resonance diagnostic technique (13C-MRI) for use in the diagnosis of cancer. In particular, upon administration of said 1-13C-2-oxoglutarate, signals of 1-13C-glutamate are detected. More in particular, different MR signals from13...

  8. Case study of elevated layers of high sulfate concentration

    International Nuclear Information System (INIS)

    McNaughton, D.J.; Orgill, M.M.

    1979-01-01

    During studies in August 1976 that were part of the Multi-State Atmospheric Power Production Pollutant Study (MAP3S), Alkezweeny et al., (1977) noted that in the Milwaukee urban plume, layers of relatively high sulfate concentrations occurred at high altitudes with respect to the boundary layer. This paper represents a progress report on studies undertaken to investigate possible causes for a bimodel vertical profile of sulfate concentrations. Data presented by Alkezweeny et al., (1977) serve as a basis for this study. Data from August 23, 1976, and August 24, 1978, indicate concentrations relatively high in sulfate, at 1000 and 6000 ft, respectively, with lower concentrations at lower altitudes. Concentrations of trace metals also indicate no peaks in the vertical concentration profiles above the surface. Initial studies of the high, elevated sulfate concentrations have centered on the August 23 measurements taken over southeast Wisconsin using synoptic data from the national weather service, emissions data from the national emissions data bank system (EPA), air quality data from the national air surveillance network (EPA), and satellite photographs from the EROS Data Center

  9. High mobility and high concentration Type-III heterojunction FET

    Science.gov (United States)

    Tsu, R.; Fiddy, M. A.; Her, T.

    2018-02-01

    The PN junction was introduced in transistors by doping, resulting in high losses due to Coulomb scattering from the dopants. The MOSFET introduced carriers in the form of electrons and holes with an applied bias to the oxide barrier, resulting in carrier transfer without doping. This avoids high scattering losses and dominates the IC industries. With heterojunctions having valence-band maxima near and even above the conduction-band minimum in the formation of Type-III superlattices, very useful devices, introduced by Tsu, Sai-Halacz, and Esaki, soon followed. If the layer thicknesses are more than the carrier mean-free-path, incoherent scattering results in the formation of carrier transfer via diffusion instead of opening up new energy gaps. The exploitation of carriers without scattering represents a new and significant opportunity in what we call a Broken Gap Heterojunction FET.

  10. Differences in Swallowing between High and Low Concentration Taste Stimuli

    Directory of Open Access Journals (Sweden)

    Ahmed Nagy

    2014-01-01

    Full Text Available Taste is a property that is thought to potentially modulate swallowing behavior. Whether such effects depend on taste, intensity remains unclear. This study explored differences in the amplitudes of tongue-palate pressures in swallowing as a function of taste stimulus concentration. Tongue-palate pressures were collected in 80 healthy women, in two age groups (under 40, over 60, stratified by genetic taste status (nontasters, supertasters. Liquids with different taste qualities (sweet, sour, salty, and bitter were presented in high and low concentrations. General labeled magnitude scale ratings captured perceived taste intensity and liking/disliking of the test liquids. Path analysis explored whether factors of taste, concentration, age group, and/or genetic taste status impacted: (1 perceived intensity; (2 palatability; and (3 swallowing pressures. Higher ratings of perceived intensity were found in supertasters and with higher concentrations, which were more liked/disliked than lower concentrations. Sweet stimuli were more palatable than sour, salty, or bitter stimuli. Higher concentrations elicited stronger tongue-palate pressures independently and in association with intensity ratings. The perceived intensity of a taste stimulus varies as a function of stimulus concentration, taste quality, participant age, and genetic taste status and influences swallowing pressure amplitudes. High-concentration salty and sour stimuli elicit the greatest tongue-palate pressures.

  11. Concentration of High Level Radioactive Liquid Waste. Basic data acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Juvenelle, A.; Masson, M.; Garrido, M.H. [DEN/VRH/DRCP/SCPS/LPCP, BP 17171 - 30207 Bagnols sur Ceze Cedex (France)

    2008-07-01

    Full text of publication follows: In order to enhance its knowledge about the concentration of high level liquid waste (HLLW) from the nuclear fuel reprocessing process, a program of studies was defined by Cea. In a large field of acidity, it proposes to characterize the concentrated solution and the obtained precipitates versus the concentration factor. Four steps are considered: quantification of the salting-out effect on the concentrate acidity, acquisition of solubility data, precipitates characterisation versus the concentration factor through aging tests and concentration experimentation starting from simulated fission products solutions. The first results, reported here, connect the acidity of the concentrated solution to the concentration factor and allow us to precise the field of acidity (4 to 12 N) for the next experiments. In this field, solubility data of various elements (Ba, Sr, Zr...) are separately measured at room temperature, in nitric acid in a first time, then in the presence of various species present in medium (TBP, PO{sub 4}{sup 3-}). The reactions between these various elements are then investigated (formation of insoluble mixed compounds) by following the concentration cations in solution and characterising the precipitates. (authors)

  12. Extremely high concentration of folates in premature newborns.

    Science.gov (United States)

    Zikavska, T; Brucknerova, I

    2014-01-01

    Extremely high concentration of folates in premature newborns: case reports. Folates are a group of water soluble compounds, which are important for metabolic processes in human body. These are important during periods of rapid cell growth. The most accurate indicator of long-term folate level status in the body is the determination of red blood cell (RBC) folate concentrations. The optimal level of RBC folate is not known in neonatal period. Authors discuss the reasons for extremely high level of RBC folate concentrations. In our work we present the cases of two premature newborns with extremely high level of RBC folate concentrations, which were analyzed immunochemically on the first day of life and after six weeks of life. In both cases we measured RBC folate concentrations on the 1st day of life. After 6 weeks we found extremely high RBC folate concentration level (5516.67 ng/ml) in the first case after RBC transfusions. In second case after two months of life the RBC folate concentration level was doubled (2335.1 ng/ml) until 24 hours after RBC transfusion compared to levels after birth. The normal range of RBC folate values vary in newborns. The upper limit of daily dose of folic acid in pregnancy and neonatal period is not known. On the other hand it is an easily excreted water-soluble vitamin but in premature newborn it can lead to the disruption of metabolic balance and slow its degradation. Some factors can have an impact on RBC folate concentration. Blood transfusion can be one of the main influences on RBC folate concentration. To clarify these mechanisms further studies are required (Ref. 29).

  13. A compact spectrum splitting concentrator for high concentration photovoltaics based on the dispersion of a lens

    Science.gov (United States)

    He, J.; Flowers, C. A.; Yao, Y.; Atwater, H. A.; Rockett, A. A.; Nuzzo, R. G.

    2018-06-01

    Photovoltaic devices used in conjunction with functional optical elements for light concentration and spectrum splitting are known to be a viable approach for highly efficient photovoltaics. Conventional designs employ discrete optical elements, each with the task of either performing optical concentration or separating the solar spectrum. In the present work, we examine the performance of a compact photovoltaic architecture in which a single lens plays a dual role as both a concentrator and a spectrum splitter, the latter made possible by exploiting its intrinsic dispersion. A four-terminal two-junction InGaP/GaAs device is prepared to validate the concept and illustrates pathways for improvements. A spectral separation in the visible range is demonstrated at the focal point of a plano-convex lens with a geometric concentration ratio of 1104X with respect to the InGaP subcell.

  14. Multiphysics modelling and experimental validation of high concentration photovoltaic modules

    International Nuclear Information System (INIS)

    Theristis, Marios; Fernández, Eduardo F.; Sumner, Mike; O'Donovan, Tadhg S.

    2017-01-01

    Highlights: • A multiphysics modelling approach for concentrating photovoltaics was developed. • An experimental campaign was conducted to validate the models. • The experimental results were in good agreement with the models. • The multiphysics modelling allows the concentrator’s optimisation. - Abstract: High concentration photovoltaics, equipped with high efficiency multijunction solar cells, have great potential in achieving cost-effective and clean electricity generation at utility scale. Such systems are more complex compared to conventional photovoltaics because of the multiphysics effect that is present. Modelling the power output of such systems is therefore crucial for their further market penetration. Following this line, a multiphysics modelling procedure for high concentration photovoltaics is presented in this work. It combines an open source spectral model, a single diode electrical model and a three-dimensional finite element thermal model. In order to validate the models and the multiphysics modelling procedure against actual data, an outdoor experimental campaign was conducted in Albuquerque, New Mexico using a high concentration photovoltaic monomodule that is thoroughly described in terms of its geometry and materials. The experimental results were in good agreement (within 2.7%) with the predicted maximum power point. This multiphysics approach is relatively more complex when compared to empirical models, but besides the overall performance prediction it can also provide better understanding of the physics involved in the conversion of solar irradiance into electricity. It can therefore be used for the design and optimisation of high concentration photovoltaic modules.

  15. Evaluation of radionuclide concentrations in high-level radioactive wastes

    International Nuclear Information System (INIS)

    Fehringer, D.J.

    1985-10-01

    This report describes a possible approach for development of a numerical definition of the term ''high-level radioactive waste.'' Five wastes are identified which are recognized as being high-level wastes under current, non-numerical definitions. The constituents of these wastes are examined and the most hazardous component radionuclides are identified. This report suggests that other wastes with similar concentrations of these radionuclides could also be defined as high-level wastes. 15 refs., 9 figs., 4 tabs

  16. High indoor radon concentrations in some Swedish waterworks

    International Nuclear Information System (INIS)

    Aakerblom, G.; Hagberg, N.; Mjoenes, L.; Heiberg, A.

    2002-01-01

    High indoor radon concentrations in buildings used for water treatment are not uncommon. When raw water is processed in an open system radon escapes from the water to the indoor air of the premises. It is not unusual that the staff of the waterworks have their offices in the building where the water is processed. If large volumes of water are processed and the evaporated radon can reach the workplaces the indoor radon concentration can be very high even if the radon concentration of the raw water is moderate. Groundwaters from aquifers in bedrock and soil and surface water that has been infiltrated through deposits of sand or gravel have the potential to cause high indoor radon levels. In surface water emanating directly from a lake or a river the radon concentrations are normally too low to cause problems. Three waterworks in central Sweden have been studied, Ludvika, Fredriksberg and Kolbaeck. The radon concentrations in the raw water of these waterworks are from 85 Bq/l to 300 Bq/l. Average indoor radon concentrations exceeding 17,000 Bq/m 3 have been measured in Ludvika with peaks of almost 37,000 Bq/m 3 . In Kolbaeck radon concentrations up to 56,000 Bq/m 3 have been measured. It is quite possible that employees of waterworks can receive doses exceeding 20 mSv per year (calculated according to ICRP:s dose conversion convention). Measurements of radon and gamma radiation from the waterworks are reported and methods to lower the indoor radon concentrations are discussed. (author)

  17. Hyperpolarized Amino Acid Derivatives as Multivalent Magnetic Resonance pH Sensor Molecules

    Directory of Open Access Journals (Sweden)

    Christian Hundshammer

    2018-02-01

    Full Text Available pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (pKa. Proteinogenic amino acids are biocompatible, can be hyperpolarized and have at least two pH sensitive moieties. However, they do not exhibit a pH sensitivity in the physiologically relevant pH range. Here, we developed a systematic approach to tailor the pKa of molecules using modifications of carbon chain length and derivatization rendering these molecules interesting for pH biosensing. Notably, we identified several derivatives such as [1-13C]serine amide and [1-13C]-2,3-diaminopropionic acid as novel pH sensors. They bear several spin-1/2 nuclei (13C, 15N, 31P with high sensitivity up to 4.8 ppm/pH and we show that 13C spins can be hyperpolarized with dissolution dynamic polarization (DNP. Our findings elucidate the molecular mechanisms of chemical shift pH sensors that might help to design tailored probes for specific pH in vivo imaging applications.

  18. Denitrification of fertilizer wastewater at high chloride concentration

    DEFF Research Database (Denmark)

    Ucisik, Ahmed Süheyl; Henze, Mogens

    Wastewater from fertilizer industry is characterized by high contents of chloride concentration, which normally vary between 60 and 76 g/l. Experiments with bilogical denitrification were performed in lab-scale "fill and draw" reactors with synthetic wastewater with chloride concentrations up to 77.......4 g/l. The results of the experiments showed that biological denitrification was feasible at the extreme environmental conditions prevailing in fertilizer wastewater. Stable continuous biological denitrfication of the synthetic high chloride wastewater was performed up to 77.4 g Cl/l at 37 degree C...

  19. Axonal and glial currents activated during the post-tetanic hyperpolarization in non-myelinated nerve.

    Science.gov (United States)

    Robert, A; Jirounek, P

    1998-07-01

    Changes in membrane potential and potassium concentration in the extracellular space ([K+]e) of rabbit vagus nerve were measured simultaneously during electrical activity and during the period of recovery using a modified sucrose-gap method and potassium-sensitive microelectrodes. After stimulation for 15 s at 15 Hz the main activity-induced increase in [K+]e reached 16.9 mM. This increase in [K+]e was paralleled by a depolarization of the preparation. The period of activity was followed by a post-tetanic hyperpolarization (PTH) lasting tens of seconds, generated by the axonal electrogenic Na+-K+ pump and to a lesser extent by the pump of the surrounding Schwann cells. The amplitude of the PTH dramatically increased in experiments in which inward currents were blocked by removal of Cl– or after application of Cs+ or Ba2+, indicating that under normal conditions the current generated by the Na+-K+ pump is strongly short-circuited. A pharmacological and kinetic study showed that these currents are: (1) the hyperpolarization-activated current I h, and (2) the inwardly rectifying I KIR current. The results show that the latter originates from Schwann cells. Our data indicate that in non-myelinated nerves there is a subtle association of inward ionic channels which (1) helps the cell to maintain an optimal membrane potential after a period of activity, and (2) contributes to the removal of excess K+ from the extracellular space.

  20. Investigating tumor perfusion by hyperpolarized (13) C MRI with comparison to conventional gadolinium contrast-enhanced MRI and pathology in orthotopic human GBM xenografts

    DEFF Research Database (Denmark)

    Park, Ilwoo; von Morze, Cornelius; Lupo, Janine M

    2016-01-01

    glioblastoma (GBM) model for the characterization of tumor perfusion and compared with standard Gd-based dynamic susceptibility contrast (DSC) MRI data and immunohistochemical analysis from resected brains. Distinct HMCP perfusion characteristics were observed within the GBM tumors compared with contralateral...... for tumor that exhibited high levels of hyperpolarized HMCP signal. The results from this study have demonstrated that hyperpolarized HMCP data can be used as an indicator of tumor perfusion in an orthotopic xenograft model for GBM. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc....

  1. Atmospheric conditions during high ragweed pollen concentrations in Zagreb, Croatia

    Science.gov (United States)

    Prtenjak, Maja Telišman; Srnec, Lidija; Peternel, Renata; Madžarević, Valentina; Hrga, Ivana; Stjepanović, Barbara

    2012-11-01

    We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (> 600 grains/m3) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m3. Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

  2. Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Krogstad, Daniel V. [Biosystems and; Wang, Dongbo [Biosystems and; Lin-Gibson, Sheng [Biosystems and

    2017-08-31

    Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.

  3. High-concentration planar microtracking photovoltaic system exceeding 30% efficiency

    Science.gov (United States)

    Price, Jared S.; Grede, Alex J.; Wang, Baomin; Lipski, Michael V.; Fisher, Brent; Lee, Kyu-Tae; He, Junwen; Brulo, Gregory S.; Ma, Xiaokun; Burroughs, Scott; Rahn, Christopher D.; Nuzzo, Ralph G.; Rogers, John A.; Giebink, Noel C.

    2017-08-01

    Prospects for concentrating photovoltaic (CPV) power are growing as the market increasingly values high power conversion efficiency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high efficiency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system 660× concentration ratio over a 140∘ full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-efficient commercial silicon solar cell by generating >50% more energy per unit area per day in a direct head-to-head competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the efficiency of rooftop solar panels at a commercially relevant concentration ratio.

  4. Beryllium-10 concentrations in water samples of high northern latitudes

    Energy Technology Data Exchange (ETDEWEB)

    Strobl, C.; Eisenhauer, A.; Schulz, V.; Baumann, S.; Mangini, A. [Heidelberger Akademie der Wissenschaften, Heildelberg (Germany); Kubik, P.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    {sup 10}Be concentrations in the water column of high northern latitudes were not available so far. We present different {sup 10}Be profiles from the Norwegian-Greenland Sea, the Arctic Ocean, and the Laptev Sea. (author) 3 fig., 3 refs.

  5. Effects of high concentration of chromium stress on physiological ...

    African Journals Online (AJOL)

    We studied the effects of high concentration of chromium (Cr) stress on physiological and biochemical characters and accumulation of Cr in Pingyang Tezao tea [Camellia sinensis (L) O. Kutze 'Pingyangtezao'] through a pot experiment. The results show that the indicators of photosynthesis were all suppressed with ...

  6. The virucidal spectrum of a high concentration alcohol mixture

    NARCIS (Netherlands)

    van Engelenburg, F. A. C.; Terpstra, F. G.; Schuitemaker, H.; Moorer, W. R.

    2002-01-01

    The virucidal spectrum of a high concentration alcohol mixture (80% ethanol and 5% isopropanol) was determined for a broad series of lipid-enveloped (LE) and non-lipid-enveloped (NLE) viruses covering all relevant blood-borne viruses. LE viruses were represented by human immunodeficiency virus

  7. Magnetic Resonance Angiography in the Pig using Hyperpolarized Water

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Bowen, Sean; Laustsen, Christoffer

    , the magnetization achievable with hyperpolarized water is superior to other nuclei. Methods A 1 mL sample of 50% water and 50% glycerol with 30 mM TEMPO is polarized in a Spinlab (GE Healthcare) at 5 T, 0.9 K, 139.9 GHz for an hour. The sample is rapidly dissolved in 16 mL deoxygenized dissolution medium (DM......Introduction Magnetic Resonance Angiography (MRA) is an important tool in diagnostics of medical conditions such as emboli, stenosis and aneurysms. Sub-millimetre resolution can be obtained with proton imaging, and further optimization can be obtained with Gd-based blood pool agents1. However......, the acquisition time is several minutes, and conventional MRA methods thus fail to image within a single respiration or heartbeat and therefore suffers from motion artefacts. We demonstrate that hyperpolarized (HP) water can be used as an imaging agent to provide subsecond angiographies in pigs. Previous work...

  8. Rheological behavior of high-concentration sodium caseinate dispersions.

    Science.gov (United States)

    Loveday, Simon M; Rao, M Anandha; Creamer, Lawrence K; Singh, Harjinder

    2010-03-01

    Apparent viscosity and frequency sweep (G', G'') data for sodium caseinate dispersions with concentrations of approximately 18% to 40% w/w were obtained at 20 degrees C; colloidal glass behavior was exhibited by dispersions with concentration >or=23% w/w. The high concentrations were obtained by mixing frozen powdered buffer with sodium caseinate in boiling liquid nitrogen, and allowing the mixtures to thaw and hydrate at 4 degrees C. The low-temperature G'-G'' crossover seen in temperature scans between 60 and 5 degrees C was thought to indicate gelation. Temperature scans from 5 to 90 degrees C revealed gradual decrease in G' followed by plateau values. In contrast, G'' decreased gradually and did not reach plateau values. Increase in hydrophobicity of the sodium caseinate or a decrease in the effective volume fraction of its aggregates may have contributed to these phenomena. The gelation and end of softening temperatures of the dispersions increased with the concentration of sodium caseinate. From an Eldridge-Ferry plot, the enthalpy of softening was estimated to be 29.6 kJ mol(-1). The results of this study should be useful for creating new products with high concentrations of sodium caseinate.

  9. Investigation of the areas of high radon concentration in Gyeongju

    International Nuclear Information System (INIS)

    Lee, Jung Min; Park, Chan Hee; Kim, Shin Jae; Moon, Joo Hyun

    2013-01-01

    The aim of this study was to survey the radon concentrations at 21 elementary schools in Gyeongju, Republic of Korea, to identify those schools with high radon concentrations. Considering their geological characteristics and the preliminary survey results, three schools were finally placed under close scrutiny. For these three schools, continuous measurements over 48 h were taken at the principal's and administration office. The radon concentrations at one school, Naenam, exceeded the action level (148 Bq/m 3 ) established by the U.S. EPA, while those at the other two schools were below that level. - Highlights: • Preliminary measurements of the indoor radon concentrations were performed at the auditoriums in 23 elementary schools in Gyeongju. • Considering the geological characteristics and preliminary survey results, three elementary schools were screened for closer scrutiny. • For the three schools, continuous measurements were made at their principal's and administration offices over 48-h period. • The scrutiny revealed one elementary school of high radon concentration much higher than the U.S. EPA action level

  10. 16-Channel surface coil for 13C-hyperpolarized spectroscopic imaging of cardiac metabolism in pig heart

    DEFF Research Database (Denmark)

    Frijia, Francesca; Santarelli, Maria Filomena; Koellisch, Ulrich

    2016-01-01

    Magnetic resonance spectroscopy (MRS) of hyperpolarized 13C pyruvate and its metabolites in large animal models is a powerful tool for assessing cardiac metabolism in patho-physiological conditions. In 13C studies, a high signal-to-noise ratio (SNR) is crucial to overcome the intrinsic data quality...... both targets. In this study, a 16-channel receive surface coil was designed for 13C hyperpolarized studies of the pig heart with a clinical 3-T scanner. The coil performance was characterized by phantom experiments and compared with that of a birdcage coil used in transmit/receive mode. Segmental...... of the 16-channel coil is recommended for studies of septal and anterior LV walls....

  11. Unphysiologically high magnesium concentrations support chondrocyte proliferation and redifferentiation.

    Science.gov (United States)

    Feyerabend, Frank; Witte, Frank; Kammal, Michael; Willumeit, Regine

    2006-12-01

    The effect of unphysiologically high extracellular magnesium concentrations on chondrocytes, induced by the supplementation of magnesium sulfate, was studied using a 3-phase tissue engineering model. The experiments showed that chondrocyte proliferation and redifferentiation, on the gene and protein expression level, are enhanced. A negative influence was found during chondrogenesis where an inhibition of extracellular matrix formation was observed. In addition, a direct impact on chondrocyte metabolism, elevated magnesium concentrations also affected growth factor effectiveness by consecutive influences during chondrogenesis. All observations were dosage dependent. The results of this study indicate that magnesium may be a useful tool for cartilage tissue engineering.

  12. Highly concentrated zinc oxide nanocrystals sol with strong blue emission

    International Nuclear Information System (INIS)

    Vafaee, M.; Sasani Ghamsari, M.; Radiman, S.

    2011-01-01

    Highly concentrated ZnO sol was synthesized by an improved sol-gel method. Water was used as a modifier to control the sol-gel reaction and provide a way to increase the sol concentration. Concentration of ZnO in the prepared sol is higher than from other methods. Optical absorption and photoluminescence were used to investigate optical properties of the prepared sol. FTIR test was performed to study the influence of water on the compounds of as-prepared sol. The size and morphology of ZnO nanoparticles have been studied by HRTEM. The prepared colloidal ZnO nanocrystals have narrow size distribution (5-8 nm) and showed strong blue emission. The prepared sol has enough potential for optoelectronic applications. - Research highlights: → Novel sol-gel route has been employed to prepare highly concentrated ZnO colloidal nanocrystals. → Water has been used to control the sources of emission in synthesized material. → A strong blue luminescent material has been obtained.

  13. MO-DE-206-03: Quantifying Metabolism with Hyperpolarized MR

    Energy Technology Data Exchange (ETDEWEB)

    Bankson, J. [The University of Texas M.D. Anderson Cancer Center (United States)

    2016-06-15

    In this symposium jointly sponsored by the World Molecular Imaging Society (WMIS) and the AAPM, luminary speakers on imaging metabolism will discuss three impactful topics. The first presentation on Cellular Metabolism of FDG will be given by Guillem Pratx (Stanford). This presentation will detail new work on looking at how the most common molecular imaging agent, fluoro-deoxy-glucose is metabolized at a cellular level. This will be followed by a talk on an improved approach to whole-body PET imaging by Simon Cherry (UC Davis). Simon’s work on a new whole-body PET imaging system promises to have dramatic improvement in our ability to detect and characterize cancer using PET. Finally, Jim Bankson (MD Anderson) will discuss extremely sophisticated approaches to quantifying hyperpolarized-13-C pyruvate metabolism using MR imaging. This technology promises to compliment the exquisite sensitivity of PET with an ability to measure not just uptake, but tumor metabolism. Learning Objectives: Understand the metabolism of FDG at a cellular level. Appreciate the engineering related to a novel new high-sensitivity whole-body PET imaging system. Understand the process of hyperpolarization, how pyruvate relates to metabolism and how advanced modeling can be used to better quantify this data. G. Pratx, Funding: 5R01CA186275, 1R21CA193001, and Damon Runyon Cancer Foundation. S. Cherry, National Institutes of Health; University of California, Davis; Siemens Medical SolutionsJ. Bankson, GE Healthcare; NCI P30-CA016672; CPRIT PR140021-P5.

  14. Effects of superparamagnetic iron oxide nanoparticles on the longitudinal and transverse relaxation of hyperpolarized xenon gas

    Science.gov (United States)

    Burant, Alex; Antonacci, Michael; McCallister, Drew; Zhang, Le; Branca, Rosa Tamara

    2018-06-01

    SuperParamagnetic Iron Oxide Nanoparticles (SPIONs) are often used in magnetic resonance imaging experiments to enhance Magnetic Resonance (MR) sensitivity and specificity. While the effect of SPIONs on the longitudinal and transverse relaxation time of 1H spins has been well characterized, their effect on highly diffusive spins, like those of hyperpolarized gases, has not. For spins diffusing in linear magnetic field gradients, the behavior of the magnetization is characterized by the relative size of three length scales: the diffusion length, the structural length, and the dephasing length. However, for spins diffusing in non-linear gradients, such as those generated by iron oxide nanoparticles, that is no longer the case, particularly if the diffusing spins experience the non-linearity of the gradient. To this end, 3D Monte Carlo simulations are used to simulate the signal decay and the resulting image contrast of hyperpolarized xenon gas near SPIONs. These simulations reveal that signal loss near SPIONs is dominated by transverse relaxation, with little contribution from T1 relaxation, while simulated image contrast and experiments show that diffusion provides no appreciable sensitivity enhancement to SPIONs.

  15. Nonfaradaic nanoporous electrochemistry for conductometry at high electrolyte concentration.

    Science.gov (United States)

    Bae, Je Hyun; Kang, Chung Mu; Choi, Hyoungseon; Kim, Beom Jin; Jang, Woohyuk; Lim, Sung Yul; Kim, Hee Chan; Chung, Taek Dong

    2015-02-17

    Nanoporous electrified surfaces create a unique nonfaradaic electrochemical behavior that is sensitively influenced by pore size, morphology, ionic strength, and electric field modulation. Here, we report the contributions of ion concentration and applied ac frequency to the electrode impedance through an electrical double layer overlap and ion transport along the nanopores. Nanoporous Pt with uniform pore size and geometry (L2-ePt) responded more sensitively to conductivity changes in aqueous solutions than Pt black with poor uniformity despite similar real surface areas and enabled the previously difficult quantitative conductometry measurements at high electrolyte concentrations. The nanopores of L2-ePt were more effective in reducing the electrode impedance and exhibited superior linear responses to not only flat Pt but also Pt black, leading to successful conductometric detection in ion chromatography without ion suppressors and at high ionic strengths.

  16. Biodegradation studies of oil sludge containing high hydrocarbons concentration

    International Nuclear Information System (INIS)

    Olguin-Lora, P.; Munoz-Colunga, A.; Castorena-Cortes, G.; Roldan-Carrillo, T.; Quej Ake, L.; Reyes-Avila, J.; Zapata-Penasco, I.; Marin-Cruz, J.

    2009-01-01

    Oil industry has a significant impact on environment due to the emission of, dust, gases, waste water and solids generated during oil production all the way to basic petrochemical product manufacturing stages. the aim of this work was to evaluate the biodegradation of sludge containing high hydrocarbon concentration originated by a petroleum facility. A sludge sampling was done at the oil residuals pool (ORP) on a gas processing center. (Author)

  17. High Concentrations of Tranexamic Acid Inhibit Ionotropic Glutamate Receptors.

    Science.gov (United States)

    Lecker, Irene; Wang, Dian-Shi; Kaneshwaran, Kirusanthy; Mazer, C David; Orser, Beverley A

    2017-07-01

    The antifibrinolytic drug tranexamic acid is structurally similar to the amino acid glycine and may cause seizures and myoclonus by acting as a competitive antagonist of glycine receptors. Glycine is an obligatory co-agonist of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. Thus, it is plausible that tranexamic acid inhibits NMDA receptors by acting as a competitive antagonist at the glycine binding site. The aim of this study was to determine whether tranexamic acid inhibits NMDA receptors, as well as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate subtypes of ionotropic glutamate receptors. Tranexamic acid modulation of NMDA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, and kainate receptors was studied using whole cell voltage-clamp recordings of current from cultured mouse hippocampal neurons. Tranexamic acid rapidly and reversibly inhibited NMDA receptors (half maximal inhibitory concentration = 241 ± 45 mM, mean ± SD; 95% CI, 200 to 281; n = 5) and shifted the glycine concentration-response curve for NMDA-evoked current to the right. Tranexamic acid also inhibited α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (half maximal inhibitory concentration = 231 ± 91 mM; 95% CI, 148 to 314; n = 5 to 6) and kainate receptors (half maximal inhibitory concentration = 90 ± 24 mM; 95% CI, 68 to 112; n = 5). Tranexamic acid inhibits NMDA receptors likely by reducing the binding of the co-agonist glycine and also inhibits α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate receptors. Receptor blockade occurs at high millimolar concentrations of tranexamic acid, similar to the concentrations that occur after topical application to peripheral tissues. Glutamate receptors in tissues including bone, heart, and nerves play various physiologic roles, and tranexamic acid inhibition of these receptors may contribute to adverse drug effects.

  18. Effects of high nitrogen concentrations on the growth of submersed macrophytes at moderate phosphorus concentrations.

    Science.gov (United States)

    Yu, Qing; Wang, Hong-Zhu; Li, Yan; Shao, Jian-Chun; Liang, Xiao-Min; Jeppesen, Erik; Wang, Hai-Jun

    2015-10-15

    Eutrophication of lakes leading to loss of submersed macrophytes and higher turbidity is a worldwide phenomenon, attributed to excessive loading of phosphorus (P). However, recently, the role of nitrogen (N) for macrophyte recession has received increasing attention. Due to the close relationship between N and P loading, disentanglement of the specific effects of these two nutrients is often difficult, and some controversy still exists as to the effects of N. We studied the effects of N on submersed macrophytes represented by Vallisneria natans (Lour.) Hara in pots positioned at three depths (0.4 m, 0.8 m, and 1.2 m to form a gradient of underwater light conditions) in 10 large ponds having moderate concentrations of P (TP 0.03 ± 0.04 mg L(-1)) and five targeted concentrations of total nitrogen (TN) (0.5, 2, 10, 20, and 100 mg L(-1)), there were two ponds for each treatment. To study the potential shading effects of other primary producers, we also measured the biomass of phytoplankton (ChlaPhyt) and periphyton (ChlaPeri) expressed as chlorophyll a. We found that leaf length, leaf mass, and root length of macrophytes declined with increasing concentrations of TN and ammonium, while shoot number and root mass did not. All the measured growth indices of macrophytes declined significantly with ChlaPhyt, while none were significantly related to ChlaPeri. Neither ChlaPhyt nor ChlaPeri were, however, significantly negatively related to the various N concentrations. Our results indicate that shading by phytoplankton unrelated to the variation in N loading and perhaps toxic stress exerted by high nitrogen were responsible for the decline in macrophyte growth. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. μ opioid receptor activation hyperpolarizes respiratory-controlling Kölliker-Fuse neurons and suppresses post-inspiratory drive.

    Science.gov (United States)

    Levitt, Erica S; Abdala, Ana P; Paton, Julian F R; Bissonnette, John M; Williams, John T

    2015-10-01

    the neuron in response to either current injection or local application of glutamate. In voltage-clamp recordings the outward current produced by the opioid agonist ME was concentration dependent, reversed at the potassium equilibrium potential and was blocked by BaCl2 , characteristics of a G protein-coupled inwardly rectifying potassium (GIRK) conductance. The clinically used drug morphine produced an outward current in KF neurons with similar potency to morphine-mediated currents in locus coeruleus brain slice preparations. Thus, the population of KF neurons that are hyperpolarized by μ opioid agonists are likely mediators of the opioid-induced loss of post-inspiration and induction of apneusis. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  20. Practical design constraints for using secondary concentrators at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    O' Gallagher, J.J.; Winston, R.

    1999-07-01

    The optical advantages of using nonimaging secondary concentrators in two-stage solar thermal dish systems are well understood. However, practical questions having to do with the thermal behavior of any secondary and its possible effects on the performance of cavity type receivers have only recently begun to be investigated. A few years ago an experimental demonstration of a trumpet type nonimaging secondary concentrator was carried out with a cavity receiver operating 660 C in combination with the Cummins Power Generation CPG-460 7.5 kWe concentrator system. Lessons learned from this and previous experiments are reviewed. The tests alleviated any operational concerns about the effectiveness of active water cooling and have shown that secondaries can be operated successfully at high temperatures without significant problems. There was no evidence of direct heat loss from the hot receiver to the cooled trumpet. The optical quality of any primary can be expected to fall well below design goals and to deteriorate further with time. This expectation should be taken into account in planning future experiments and developing new concentrating systems.

  1. Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

    International Nuclear Information System (INIS)

    Souza, J.A.B.; Durazzo, M.

    2010-01-01

    IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 gU/cm 3 by using the U 3 Si 2 -Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 gU/cm 3 for the U 3 Si 2 -Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian-Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

  2. Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Jose Antonio Batista de; Durazzo, Michelangelo, E-mail: jasouza@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 g U/c m3 by using the U{sub 3}Si{sub 2}-Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 g U/c m3 for the U{sub 3}Si{sub 2}-Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian- Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

  3. Hyperpolarized krypton-83 as a contrast agent for magnetic resonance imaging.

    Science.gov (United States)

    Pavlovskaya, Galina E; Cleveland, Zackary I; Stupic, Karl F; Basaraba, Randall J; Meersmann, Thomas

    2005-12-20

    For the first time, magnetic resonance imaging (MRI) with hyperpolarized (hp) krypton-83 (83Kr) has become available. The relaxation of the nuclear spin of 83Kr atoms (I = 9/2) is driven by quadrupolar interactions during brief adsorption periods on surrounding material interfaces. Experiments in model systems reveal that the longitudinal relaxation of hp 83Kr gas strongly depends on the chemical composition of the materials. The relaxation-weighted contrast in hp 83Kr MRI allows for the distinction between hydrophobic and hydrophilic surfaces. The feasibility of hp 83Kr MRI of airways is tested in canine lung tissue by using krypton gas with natural abundance isotopic distribution. Additionally, the influence of magnetic field strength and the presence of a breathable concentration of molecular oxygen on longitudinal relaxation are investigated.

  4. Liver imaging with MDCT and high concentration contrast media

    International Nuclear Information System (INIS)

    Spielmann, Audrey L.

    2003-01-01

    Liver imaging has advanced greatly over the last 10 years with helical CT capability and more recently the addition of multidetector-row CT (MDCT). Multidetector CT technology facilitates imaging at faster speeds with improved image quality and less breathing artifact [Abdom. Imaging 25 (2000) 643]. Exquisite three-dimensional data sets can be obtained with thin collimation providing improved lesion detection, multiplanar imaging, and the ability to perform CT angiography of the liver and mesenteric vessels. New challenges arise with this advance in technology including safety considerations. The radiation dose to the patient has increased with MDCT and this is compounded by the ability to perform multi-phase liver imaging. Furthermore, issues of contrast media administration require reconsideration including optimal timing and rate of administration, the total volume of contrast needed and the ideal iodine concentration of the contrast media. Recently, the use of high concentration contrast media (HCCM) has been explored and study results to date will be reviewed

  5. [Condition optimization for bio-oxidation of high-S and high-As gold concentrate].

    Science.gov (United States)

    Yang, Caiyun; Dong, Bowen; Wang, Meijun; Ye, Zhiyong; Zheng, Tianling; Huang, Huaiguo

    2015-12-04

    To study the effects of temperature and lixivium return on the concentrate bio-oxidation and rate of gold cyanide leaching. The bioleaching of a high-sulphur (S) and high-arsenic (As) refractory gold concentrate was conducted, and we studied the effects of different temperature (40 ° and 45 °C) and lixivium return (0 and 600 mL) on the bio-oxidation efficiency. The bacterial community structure also was investigated by 16S rRNA gene clone library. The results showed that both the temperature and lixivium return significantly influenced the oxidation system. The temperature rising elevated the oxidation level, while the addition of lixivium depressed the oxidation. Dissimilarity and DCA (detrended correspondence analysis) indicated the effect of temperature on oxidation system was much greater than lixivium. The bacterial community was comprised by Acidithiocacillus caldu (71%) Leptospirillum ferriphilum (23%) and Sulfobacillus thermosulfidooxidans (6%) indicated by the clone library, and the OTU coverage based on 97% sequence similarity was as high as 93.67%. Temperature rising to 45 T would improve the oxidation efficiency while lixivium return would decrease it. This study is helpful to provide an important guiding value for the industry cost optimization of mesophile bacterial oxidation and reduction process.

  6. Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

    International Nuclear Information System (INIS)

    Souza, Jose Antonio Batista de

    2011-01-01

    IPEN-CNEN/SP developed the technology to produce the dispersion type fuel elements for research reactors and made it available for routine production. Today, the fuel produced in IPEN-CNEN/SP is limited to the uranium concentration of 3.0 gU/cm 3 for U 3 Si 2 -Al dispersion-based and 2.3 gU/cm 3 for U 3 O 8 -Al dispersion. The increase of uranium concentration in fuel plates enables the reactivity of the reactor core reactivity to be higher and extends the fuel life. Concerning technology, it is possible to increase the uranium concentration in the fuel meat up to the limit of 4.8 gU/cm 3 in U 3 Si 2 -Al dispersion and 3.2 gU/cm 3 U 3 O 8 -Al dispersion. These dispersions are well qualified worldwide. This work aims to develop the manufacturing process of both fuel meats with high uranium concentrations, by redefining the manufacturing procedures currently adopted in the Nuclear Fuel Center of IPEN-CNEN/SP. Based on the results, it was concluded that to achieve the desired concentration, it is necessary to make some changes in the established procedures, such as in the particle size of the fuel powder and in the feeding process inside the matrix, before briquette pressing. These studies have also shown that the fuel plates, with a high concentration of U 3 Si 2 -Al, met the used specifications. On the other hand, the appearance of the microstructure obtained from U 3 O 8 -Al dispersion fuel plates with 3.2 gU/cm 3 showed to be unsatisfactory, due to the considerably significant porosity observed. The developed fabrication procedure was applied to U 3 Si 2 production at 4.8 gU/cm 3 , with enriched uranium. The produced plates were used to assemble the fuel element IEA-228, which was irradiated in order to check its performance in the IEA-R1 reactor at IPEN-CNEN/SP. These new fuels have potential to be used in the new Brazilian Multipurpose Reactor - RMB. (author)

  7. Mitigation of houses with extremely high indoor radon concentrations

    International Nuclear Information System (INIS)

    Jiranek, M.; Neznal, M.

    2006-01-01

    Full text of publication follows: The paper reports on the experience of the Czech Technical University in dealing with mitigation of houses in which unusually high indoor radon concentrations were found. The whole process of remediation is illustrated by example of an old single-family house that was built in the area formed by highly permeable soils with high radon content in the soil air. T he house has a small cellar located under 1/5 of the ground floor area. Two types of floors, i.e. timber floors and cracked concrete slabs were found in the house. As a result of extremely high radon concentration in the sub-floor region (up to 600 kBq/m 3 ) and leaky structures in contact with soil, radon concentrations around 100 kBq/m 3 in the cellar and up to 60 kBq/m 3 in the living rooms on the ground floor were measured prior to mitigation. Mitigation measures that were carried out in the house consist of reconstruction of timber floors and installation of active soil depressurization. Timber floors were replaced with concrete slab fitted with damp proof membrane, thermal insulation and floor covering. The soil depressurization system was made up of two sections. The first section is composed of the network of perforated pipes inserted in the drainage layer placed under the new floors and four perforated tubes drilled under the existing floors. The soil air from this section is extracted by means of a roof fan installed at the top of the vertical exhaust pipe running inside the living space and terminating above the roof. The second section was designed to withdraw by means of a small fan radon-laden air from the filling in the floor above the cellar and from perforated tubes drilled into the sub-floor region under the rooms adjacent to the cellar. It serves also for the active ventilation of the cellar. Pressure, temperature and radon concentration sensors were installed into the drainage layer during the reconstruction of floors to record variations in these

  8. Introduction of high oxygen concentrations into silicon wafers by high-temperature diffusion

    International Nuclear Information System (INIS)

    Casse, G.; Glaser, M.; Lemeilleur, F.; Ruzin, A.; Wegrzecki, M.

    1999-01-01

    The tolerance of silicon detectors to hadron irradiation can be improved by the introduction of a high concentration of oxygen into the starting material. High-resistivity Floating-Zone (FZ) silicon is required for detectors used in particle physics applications. A significantly high oxygen concentration (>10 17 atoms cm -3 ) cannot readily be achieved during the FZ silicon refinement. The diffusion of oxygen at elevated temperatures from a SiO 2 layer grown on both sides of a silicon wafer is a simple and effective technique to achieve high and uniform concentrations of oxygen throughout the bulk of a 300 μm thick silicon wafer

  9. Effect of membrane hyperpolarization induced by a K+ channel opener on histamine-induced Ca2+ mobilization in rabbit arterial smooth muscle.

    Science.gov (United States)

    Watanabe, Y; Suzuki, A; Suzuki, H; Itoh, T

    1996-03-01

    1. The role of membrane hyperpolarization on agonist-induced contraction was investigated in intact and alpha-toxin-skinned smooth muscles of rabbit mesenteric artery by use of the ATP-sensitive K+ channel opener, (-)-(3S,4R)-4-(N-acetyl-N-hydroxyamino)-6-cyano-3,4-dihydro-2,2- dimethyl-2H-1-benzopyran-3-ol (Y-26763), and either histamine (Hist) or noradrenaline (NA). 2. Hist (3 microM) and NA (10 microM) both produced a phasic, followed by a tonic increase in intracellular Ca2+ concentration ([Ca2+]i) and force. Y-26763 (10 microM) potently inhibited the NA-induced phasic and tonic increase in [Ca2+]i and force. In contrast, Y-26763 attenuated the Hist-induced phasic increase in [Ca2+]i and force but had almost no effect on the tonic response. However, ryanodine-treatment of muscles in order to inhibit the function of intracellular Ca2+ storage sites altered the action of Y-26763 which now attenuated the Hist-induced tonic increase in [Ca2+]i and force in a concentration-dependent manner (at concentrations > 1 microM). Glibenclamide (10 microM) attenuated the inhibitory action of Y-26763. 3. Hist (3 microM) depolarized the smooth muscle cells to the same extent as NA (10 microM). In the absence of either agonist, Y-26763 (over 30 nM) hyperpolarized the membrane and glibenclamide inhibited this hyperpolarization. Y-26763 (10 microM) almost abolished the NA-induced membrane depolarization, but only slightly attenuated the Hist-induced membrane depolarization in which the delta (delta) value (the difference before and after application of Hist) was not modified by any concentration of Y-26763. In ryanodine-treated smooth muscle cells, Y-26763 hyperpolarized the membrane and potently inhibited the membrane depolarization induced by Hist. 4. In ryanodine-treated muscle, Y-26763 had no measurable effect on the Hist-induced [Ca2+]i-force relationship. Y-26763 also had no apparent effect on the myofilament Ca(2+)-sensitivity in the presence of Hist in alpha

  10. Hyperpolarized 129Xe MRI: A viable functional lung imaging modality?

    International Nuclear Information System (INIS)

    Patz, Samuel; Hersman, F. William; Muradian, Iga; Hrovat, Mirko I.; Ruset, Iulian C.; Ketel, Stephen; Jacobson, Francine; Topulos, George P.; Hatabu, Hiroto; Butler, James P.

    2007-01-01

    The majority of researchers investigating hyperpolarized gas MRI as a candidate functional lung imaging modality have used 3 He as their imaging agent of choice rather than 129 Xe. This preference has been predominantly due to, 3 He providing stronger signals due to higher levels of polarization and higher gyromagnetic ratio, as well as its being easily available to more researchers due to availability of polarizers (USA) or ease of gas transport (Europe). Most researchers agree, however, that hyperpolarized 129 Xe will ultimately emerge as the imaging agent of choice due to its unlimited supply in nature and its falling cost. Our recent polarizer technology delivers vast improvements in hyperpolarized 129 Xe output. Using this polarizer, we have demonstrated the unique property of xenon to measure alveolar surface area noninvasively. In this article, we describe our human protocols and their safety, and our results for the measurement of the partial pressure of pulmonary oxygen (pO 2 ) by observation of 129 Xe signal decay. We note that the measurement of pO 2 by observation of 129 Xe signal decay is more complex than that for 3 He because of an additional signal loss mechanism due to interphase diffusion of 129 Xe from alveolar gas spaces to septal tissue. This results in measurements of an equivalent pO 2 that accounts for both traditional T 1 decay from pO 2 and that from interphase diffusion. We also provide an update on new technological advancements that form the foundation for an improved compact design polarizer as well as improvements that provide another order-of-magnitude scale-up in xenon polarizer output

  11. Astrocytic mitochondrial membrane hyperpolarization following extended oxygen and glucose deprivation.

    Directory of Open Access Journals (Sweden)

    Andrej Korenić

    Full Text Available Astrocytes can tolerate longer periods of oxygen and glucose deprivation (OGD as compared to neurons. The reasons for this reduced vulnerability are not well understood. Particularly, changes in mitochondrial membrane potential (Δψ(m in astrocytes, an indicator of the cellular redox state, have not been investigated during reperfusion after extended OGD exposure. Here, we subjected primary mouse astrocytes to glucose deprivation (GD, OGD and combinations of both conditions varying in duration and sequence. Changes in Δψ(m, visualized by change in the fluorescence of JC-1, were investigated within one hour after reconstitution of oxygen and glucose supply, intended to model in vivo reperfusion. In all experiments, astrocytes showed resilience to extended periods of OGD, which had little effect on Δψ(m during reperfusion, whereas GD caused a robust Δψ(m negativation. In case no Δψ(m negativation was observed after OGD, subsequent chemical oxygen deprivation (OD induced by sodium azide caused depolarization, which, however, was significantly delayed as compared to normoxic group. When GD preceded OD for 12 h, Δψ(m hyperpolarization was induced by both GD and subsequent OD, but significant interaction between these conditions was not detected. However, when GD was extended to 48 h preceding OGD, hyperpolarization enhanced during reperfusion. This implicates synergistic effects of both conditions in that sequence. These findings provide novel information regarding the role of the two main substrates of electron transport chain (glucose and oxygen and their hyperpolarizing effect on Δψ(m during substrate deprivation, thus shedding new light on mechanisms of astrocyte resilience to prolonged ischemic injury.

  12. Particulate Matter Concentrations in East Oakland's High Street Corridor

    Science.gov (United States)

    Lei, P.; Jackson, J.; Lewis, R.; Marigny, A.; Mitchell, J. D.; Nguyen, R.; Philips, B.; Randle, D.; Romero, D.; Spears, D.; Telles, C.; Weissman, D.

    2012-12-01

    Particulate matter (PM) is a complex mixture of small solid pieces and/or liquid droplets in the air. High concentrations of PM can pose a serious health hazard because inhalation can result in breathing problems and/or aggravate asthma. Long term exposure can increase the likelihood of respiratory problems like asthma and emphysema as well as cancer. The smaller the particles, the deeper they can get into the respiratory system. For this reason, the smallest particles, those smaller than 2.5 micrometers in diameter (PM2.5), are the most dangerous. PM2.5 is largely emitted from motor vehicles burning fuels that don't break down fully. Our research team investigated the levels of PM2.5 as well as particles smaller than 10 micrometers (PM10) and total suspended particulate (TSP) along the northeast-southwest trending High Street Corridor, near Fremont High School in East Oakland, California. Using the Aerocet 531 mass particle counter, team members walked through neighborhoods and along major roads within a 1 mile radius of Fremont High School. The Aerocet 531 recorded two minute average measurements of all the relevant PM sizes, which are reported in mg/m3. Measurements were consistently taken in the morning, between 8:30 and 11:30 am. Preliminary results indicate maximum readings of all PM sizes at sites that are in close proximity to a major freeway (Interstate-880). These results support our initial hypothesis that proximity to major roads and freeways, especially those with high diesel-fuel burning truck traffic, would be the primary factor affecting PM concentration levels. Preliminary median and maximum readings all suggest particulate matter levels below what the EPA would consider unhealthy or risky.

  13. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

    Directory of Open Access Journals (Sweden)

    R. S. Humphries

    2016-02-01

    Full Text Available Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3 concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between

  14. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

    Science.gov (United States)

    Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

    2016-02-01

    Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of

  15. Brain Imaging Using Hyperpolarized 129Xe Magnetic Resonance Imaging.

    Science.gov (United States)

    Chahal, Simrun; Prete, Braedan R J; Wade, Alanna; Hane, Francis T; Albert, Mitchell S

    2018-01-01

    Hyperpolarized (HP) 129 Xe magnetic resonance imaging (MRI) is a novel iteration of traditional MRI that relies on detecting the spins of 1 H. Since 129 Xe is a gaseous signal source, it can be used for lung imaging. Additionally, 129 Xe dissolves in the blood stream and can therefore be detectable in the brain parenchyma and vasculature. In this work, we provide detailed information on the protocols that we have developed to image 129 Xe within the brains of both rodents and human subjects. © 2018 Elsevier Inc. All rights reserved.

  16. Mechanisms of hyperpolarization in regenerated mature motor axons in cat

    DEFF Research Database (Denmark)

    Moldovan, Mihai; Krarup, Christian

    2004-01-01

    We found persistent abnormalities in the recovery of membrane excitability in long-term regenerated motor nerve fibres in the cat as indicated in the companion paper. These abnormalities could partly be explained by membrane hyperpolarization. To further investigate this possibility, we compared...... the changes in excitability in control nerves and long-term regenerated cat nerves (3-5 years after tibial nerve crush) during manoeuvres known to alter axonal membrane Na(+)-K(+) pump function: polarization, cooling to 20 degrees C, reperfusion after 10 min ischaemia, and up to 60 s of repetitive stimulation...

  17. Hyperpolarized Xenon Nuclear Magnetic Resonance (NMR of Building Stone Materials

    Directory of Open Access Journals (Sweden)

    Michele Mauri

    2012-09-01

    Full Text Available We have investigated several building stone materials, including minerals and rocks, using continuous flow hyperpolarized xenon (CF-HP NMR spectroscopy to probe the surface composition and porosity. Chemical shift and line width values are consistent with petrographic information. Rare upfield shifts were measured and attributed to the presence of transition metal cations on the surface. The evolution of freshly cleaved rocks exposed to the atmosphere was also characterized. The CF-HP 129Xe NMR technique is non-destructive and it could complement currently used techniques, like porosimetry and microscopy, providing additional information on the chemical nature of the rock surface and its evolution.

  18. Dynamically Decoupled 13C Spins in Hyperpolarized Nanodiamond

    Science.gov (United States)

    Rej, Ewa; Gaebel, Torsten; Boele, Thomas; Waddington, David; Reilly, David

    The spin-spin relaxation time, T2, which determines how long a quantum state remains coherent, is an important factor for many applications ranging from MRI to quantum computing. A common technique used in quantum information technology to extend the T2, involves averaging out certain noise spectra via dynamical decoupling sequences. Depending on the nature of the noise in the system, specific sequences, such as CPMG, UDD or KDD, can be tailored to optimize T2. Here we combine hyperpolarization techniques and dynamical decoupling sequences to extend the T2 of 13C nuclear spins in nanodiamond by three orders of magnitude.

  19. Field dependence of T1 for hyperpolarized [1-13C]pyruvate

    DEFF Research Database (Denmark)

    Chattergoon, N.; Martnez-Santiesteban, F.; Handler, W. B.

    2013-01-01

    conformation and properties of the dissolution media such as buffer composition, solution pH, temperature and magnetic field. We have measured the magnetic field dependence of the spin–lattice relaxation time of hyperpolarized [1-13C]pyruvate using field-cycled relaxometry. [1-13C]pyruvate was hyperpolarized...

  20. The role of level anti-crossings in nuclear spin hyperpolarization

    NARCIS (Netherlands)

    Ivanov, Konstantin L.; Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Vieth, Hans Martin; Kaptein, R

    2014-01-01

    Nuclear spin hyperpolarization is an important resource for increasing the sensitivity of NMR spectroscopy and MRI. Signal enhancements can be as large as 3-4 orders of magnitude. In hyperpolarization experiments, it is often desirable to transfer the initial polarization to other nuclei of choice,

  1. A novel MR contrast agent for angiography and perfusion: Hyperpolarized water

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh

    , hyperpolarized by dissolution Dynamic Nuclear Polarization (d-DNP), can be applied as an MRI contrast agent for angiography and perfusion. The first part of the project focuses on development of a protocol for production of large samples of hyperpolarized protons in D2O. The samples are polarized and dissolved...

  2. Metabolic imaging of patients with prostate cancer using hyperpolarized [1-¹³C]pyruvate

    DEFF Research Database (Denmark)

    Nelson, Sarah J; Kurhanewicz, John; Vigneron, Daniel B

    2013-01-01

    This first-in-man imaging study evaluated the safety and feasibility of hyperpolarized [1-¹³C]pyruvate as an agent for noninvasively characterizing alterations in tumor metabolism for patients with prostate cancer. Imaging living systems with hyperpolarized agents can result in more than 10,000-f...

  3. Hydrogen concentration and distribution in high-purity germanium crystals

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.; Luke, P.N.

    1981-10-01

    High-purity germanium crystals used for making nuclear radiation detectors are usually grown in a hydrogen ambient from a melt contained in a high-purity silica crucible. The benefits and problems encountered in using a hydrogen ambient are reviewed. A hydrogen concentration of about 2 x 10 15 cm -3 has been determined by growing crystals in hydrogen spiked with tritium and counting the tritium β-decays in detectors made from these crystals. Annealing studies show that the hydrogen is strongly bound, either to defects or as H 2 with a dissociation energy > 3 eV. This is lowered to 1.8 eV when copper is present. Etching defects in dislocation-free crystals grown in hydrogen have been found by etch stripping to have a density of about 1 x 10 7 cm -3 and are estimated to contain 10 8 H atoms each

  4. Risk factors associated with high linezolid trough plasma concentrations.

    Science.gov (United States)

    Morata, L; De la Calle, C; Gómez-Cerquera, J M; Manzanedo, L; Casals, G; Brunet, M; Cobos-Trigueros, N; Martínez, J A; Mensa, J; Soriano, A

    2016-06-01

    The major concern of linezolid is the adverse events. High linezolid trough serum concentration (Cmin) has been associated with toxicity. The aim of this study was to analyze factors associated with high Cmin. Main clinical characteristics of 104 patients treated with 600 mg/12 hours of linezolid were retrospectively reviewed. Samples were obtained just before the next dose after at least three doses and within the first 8 days of treatment. High Cmin was considered when it was >8 mg/L. Univariate and multivariate analysis were performed. 34.6% patients had a Cmin >8 mg/L, and they were older and had more frequently an estimated glomerular filtration by MDRD 8 was the renal function. Patients with an eGF 80 mL/min (OR: 4.273) and there was a trend towards a high Cmin in patients with eGF between 40-80 mL/min (OR: 2.109). High Cmin were frequent, especially in patients with MDRD <40 mL/min. Therapeutic drug monitoring could be useful to avoid toxicity in patients with renal dysfunction.

  5. Oleate induces KATP channel-dependent hyperpolarization in mouse hypothalamic glucose-excited neurons without altering cellular energy charge.

    Science.gov (United States)

    Dadak, Selma; Beall, Craig; Vlachaki Walker, Julia M; Soutar, Marc P M; McCrimmon, Rory J; Ashford, Michael L J

    2017-03-27

    The unsaturated fatty acid, oleate exhibits anorexigenic properties reducing food intake and hepatic glucose output. However, its mechanism of action in the hypothalamus has not been fully determined. This study investigated the effects of oleate and glucose on GT1-7 mouse hypothalamic cells (a model of glucose-excited (GE) neurons) and mouse arcuate nucleus (ARC) neurons. Whole-cell and perforated patch-clamp recordings, immunoblotting and cell energy status measures were used to investigate oleate- and glucose-sensing properties of mouse hypothalamic neurons. Oleate or lowered glucose concentration caused hyperpolarization and inhibition of firing of GT1-7 cells by the activation of ATP-sensitive K + channels (K ATP ). This effect of oleate was not dependent on fatty acid oxidation or raised AMP-activated protein kinase activity or prevented by the presence of the UCP2 inhibitor genipin. Oleate did not alter intracellular calcium, indicating that CD36/fatty acid translocase may not play a role. However, oleate activation of K ATP may require ATP metabolism. The short-chain fatty acid octanoate was unable to replicate the actions of oleate on GT1-7 cells. Although oleate decreased GT1-7 cell mitochondrial membrane potential there was no change in total cellular ATP or ATP/ADP ratios. Perforated patch and whole-cell recordings from mouse hypothalamic slices demonstrated that oleate hyperpolarized a subpopulation of ARC GE neurons by K ATP activation. Additionally, in a separate small population of ARC neurons, oleate application or lowered glucose concentration caused membrane depolarization. In conclusion, oleate induces K ATP- dependent hyperpolarization and inhibition of firing of a subgroup of GE hypothalamic neurons without altering cellular energy charge. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Regional alveolar partial pressure of oxygen measurement with parallel accelerated hyperpolarized gas MRI.

    Science.gov (United States)

    Kadlecek, Stephen; Hamedani, Hooman; Xu, Yinan; Emami, Kiarash; Xin, Yi; Ishii, Masaru; Rizi, Rahim

    2013-10-01

    Alveolar oxygen tension (Pao2) is sensitive to the interplay between local ventilation, perfusion, and alveolar-capillary membrane permeability, and thus reflects physiologic heterogeneity of healthy and diseased lung function. Several hyperpolarized helium ((3)He) magnetic resonance imaging (MRI)-based Pao2 mapping techniques have been reported, and considerable effort has gone toward reducing Pao2 measurement error. We present a new Pao2 imaging scheme, using parallel accelerated MRI, which significantly reduces measurement error. The proposed Pao2 mapping scheme was computer-simulated and was tested on both phantoms and five human subjects. Where possible, correspondence between actual local oxygen concentration and derived values was assessed for both bias (deviation from the true mean) and imaging artifact (deviation from the true spatial distribution). Phantom experiments demonstrated a significantly reduced coefficient of variation using the accelerated scheme. Simulation results support this observation and predict that correspondence between the true spatial distribution and the derived map is always superior using the accelerated scheme, although the improvement becomes less significant as the signal-to-noise ratio increases. Paired measurements in the human subjects, comparing accelerated and fully sampled schemes, show a reduced Pao2 distribution width for 41 of 46 slices. In contrast to proton MRI, acceleration of hyperpolarized imaging has no signal-to-noise penalty; its use in Pao2 measurement is therefore always beneficial. Comparison of multiple schemes shows that the benefit arises from a longer time-base during which oxygen-induced depolarization modifies the signal strength. Demonstration of the accelerated technique in human studies shows the feasibility of the method and suggests that measurement error is reduced here as well, particularly at low signal-to-noise levels. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  7. Alcohol consumption is associated with high concentrations of urinary hydroxytyrosol.

    Science.gov (United States)

    Schröder, Helmut; de la Torre, Rafael; Estruch, Ramón; Corella, Dolores; Martínez-González, Miguel Angel; Salas-Salvadó, Jordi; Ros, Emilio; Arós, Fernando; Flores, Gemma; Civit, Ester; Farré, Magí; Fiol, Miguel; Vila, Joan; Fernandez-Crehuet, Joaquín; Ruiz-Gutiérrez, Valentina; Lapetra, Jose; Sáez, Guillermo; Covas, María-Isabel

    2009-11-01

    Previously, we reported the presence of hydroxytyrosol in red wine and higher human urinary recovery of total hydroxytyrosol than that expected after a single red wine intake. We hypothesized that the alcohol present in wine could promote endogenous hydroxytyrosol generation. The objective was to assess the relation between alcohol consumption and urinary hydroxytyrosol concentrations. This was a cross-sectional study with baseline data from a subsample of the PREvención con DIeta MEDiterránea (PREDIMED) trial, an intervention study directed at testing the efficacy of the Mediterranean diet on the primary prevention of cardiovascular disease. Participants included 1045 subjects, aged 55-80 y, who were at high cardiovascular risk. Alcohol consumption was estimated through a validated food-frequency questionnaire. Urinary hydroxytyrosol and ethyl glucuronide, a biomarker of alcohol consumption, were measured. Urinary ethyl glucuronide concentrations were directly related to alcohol and wine consumption (P logistic regression analyses showed a significant linear trend (P 20 g (2 drinks)/d and >10 g (1 drink)/d alcohol in men and women, respectively, were associated (P wine as a source of hydroxytyrosol and alcohol as an indirect promoter of endogenous hydroxytyrosol generation. This trial was registered at controlled-trials.com/isrctn/ as ISRCTN 35739639.

  8. Thermal denitration of high concentration nitrate salts waste water

    International Nuclear Information System (INIS)

    Hwang, D. S.; Oh, J. H.; Choi, Y. D.; Hwang, S. T.; Park, J. H.; Latge, C.

    2003-01-01

    This study investigated the thermodynamic and the thermal decomposition properties of high concentration nitrate salts waste water for the lagoon sludge treatment. The thermodynamic property was carried out by COACH and GEMINI II based on the composition of nitrate salts waste water. The thermal decomposition property was carried out by TG-DTA and XRD. Ammonium nitrate and sodium nitrate were decomposed at 250 .deg. C and 730 . deg. C, respectively. Sodium nitrate could be decomposed at 450 .deg. C in the case of adding alumina for converting unstable Na 2 O into stable Na 2 O.Al 2 O 3 . The flow sheet for nitrate salts waste water treatment was proposed based on the these properties data. These will be used by the basic data of the process simulation

  9. Acquisition and Analysis of Data from High Concentration Solutions

    KAUST Repository

    Besong, Tabot M.D.

    2016-05-13

    The problems associated with ultracentrifugal analysis of macromolecular solutions at high (>10 mg/ml) are reviewed. Especially for the case of solutes which are non-monodisperse, meaningful results are not readily achievable using sedimentation velocity approaches. It is shown however by both simulation and analysis of practical data that using a modified form of an algorithm (INVEQ) published in other contexts, sedimentation equilibrium (SE) profiles can be analysed successfully, enabling topics such as oligomer presence or formation to be defined.To achieve this, it is necessary to employ an approach in which the solution density, which in an SE profile is radius-dependent, is taken into consideration. Simulation suggests that any reasonable level of solute concentration can be analysed.

  10. Acquisition and Analysis of Data from High Concentration Solutions

    KAUST Repository

    Besong, Tabot M.D.; Rowe, Arthur J.

    2016-01-01

    The problems associated with ultracentrifugal analysis of macromolecular solutions at high (>10 mg/ml) are reviewed. Especially for the case of solutes which are non-monodisperse, meaningful results are not readily achievable using sedimentation velocity approaches. It is shown however by both simulation and analysis of practical data that using a modified form of an algorithm (INVEQ) published in other contexts, sedimentation equilibrium (SE) profiles can be analysed successfully, enabling topics such as oligomer presence or formation to be defined.To achieve this, it is necessary to employ an approach in which the solution density, which in an SE profile is radius-dependent, is taken into consideration. Simulation suggests that any reasonable level of solute concentration can be analysed.

  11. Characterization of blood donors with high haemoglobin concentration

    DEFF Research Database (Denmark)

    Magnussen, K; Hasselbalch, H C; Ullum, H

    2013-01-01

    Background and Objectives  The literature contains little on the prevalence and causes of high predonation haemoglobin levels among blood donors. This study aimed to characterize and develop an algorithm to manage would-be donors with polycythaemia. Materials and Methods  Between November 2009...... and November 2011, we offered haematology consultations to blood donors with repeated haemoglobin concentration (Hb) above the WHO limit for polycythaemia vera (PV) (10·2 and 11·5 mm/16·5 and 18·5 g/dl for women and men, respectively). Investigation of such donors included Hb, haematocrit, mean cell volume......, erythropoietin, ferritin, platelet count and leucocyte count, JAK2 V617 and JAK2 exon12 analysis, as well as other routine measurements. Results  Among 46 such donors, 39 had a history of smoking, which contributes to erythrocytosis. Two had PV, five had severe hypertension, one of them because of renal artery...

  12. Highly Concentrated Acetic Acid Poisoning: 400 Cases Reviewed

    Directory of Open Access Journals (Sweden)

    Konstantin Brusin

    2012-12-01

    Full Text Available Background: Caustic substance ingestion is known for causing a wide array of gastrointestinal and systemic complications. In Russia, ingestion of acetic acid is a major problem which annually affects 11.2 per 100,000 individuals. The objective of this study was to report and analyze main complications and outcomes of patients with 70% concentrated acetic acid poisoning. Methods: This was a retrospective study of patients with acetic acid ingestion who were treated at Sverdlovsk Regional Poisoning Treatment Center during 2006 to 2012. GI mucosal injury of each patient was assessed with endoscopy according to Zargar’s scale. Data analysis was performed to analyze the predictors of stricture formation and mortality. Results: A total of 400 patients with median age of 47 yr were included. GI injury grade I was found in 66 cases (16.5%, IIa in 117 (29.3%, IIb in 120 (30%, IIIa in 27 (16.7% and IIIb in 70 (17.5%. 11% of patients developed strictures and overall mortality rate was 21%. Main complications were hemolysis (55%, renal injury (35%, pneumonia (27% and bleeding during the first 3 days (27%. Predictors of mortality were age 60 to 79 years, grade IIIa and IIIb of GI injury, pneumonia, stages “I”, “F” and “L” of kidney damage according to the RIFLE scale and administration of prednisolone. Predictors of stricture formation were ingestion of over 100 mL of acetic acid and grade IIb and IIIa of GI injury. Conclusion: Highly concentrated acetic acid is still frequently ingested in Russia with a high mortality rate. Patients with higher grades of GI injury, pneumonia, renal injury and higher amount of acid ingested should be more carefully monitored as they are more susceptible to develop fatal consequences.          

  13. Measuring glucose cerebral metabolism in the healthy mouse using hyperpolarized C-13 magnetic resonance

    DEFF Research Database (Denmark)

    Mishkovsky, Mor; Anderson, Brian; Karlsson, Magnus

    2017-01-01

    The mammalian brain relies primarily on glucose as a fuel to meet its high metabolic demand. Among the various techniques used to study cerebral metabolism, C-13 magnetic resonance spectroscopy (MRS) allows following the fate of C-13-enriched substrates through metabolic pathways. We herein...... glucose is split into 3-carbon intermediates by aldolase. This unique method allows direct detection of glycolysis in vivo in the healthy brain in a noninvasive manner....... demonstrate that it is possible to measure cerebral glucose metabolism in vivo with sub-second time resolution using hyperpolarized C-13 MRS. In particular, the dynamic C-13-labeling of pyruvate and lactate formed from C-13-glucose was observed in real time. An ad-hoc synthesis to produce [2,3,4,6,6-H-2(5), 3...

  14. Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

    International Nuclear Information System (INIS)

    Yoshida, Takahiro

    2011-01-01

    Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14 C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 o C. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH ≤ 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: → Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14 C compounds in cementitious repositories. → Nitrate-reducing bacteria can biodegrade acetate at pH ≤ 11. → Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.

  15. Modelling acceptance of sunlight in high and low photovoltaic concentration

    Energy Technology Data Exchange (ETDEWEB)

    Leutz, Ralf, E-mail: ralf.leutz@leopil.com [Leutz Optics and Illumination UG (haftungsbeschränkt), Marburg (Germany)

    2014-09-26

    A simple model incorporating linear radiation characteristics, along with the optical trains and geometrical concentration ratios of solar concentrators is presented with performance examples for optical trains of HCPV, LCPV and benchmark flat-plate PV.

  16. Modelling acceptance of sunlight in high and low photovoltaic concentration

    Science.gov (United States)

    Leutz, Ralf

    2014-09-01

    A simple model incorporating linear radiation characteristics, along with the optical trains and geometrical concentration ratios of solar concentrators is presented with performance examples for optical trains of HCPV, LCPV and benchmark flat-plate PV.

  17. Modelling acceptance of sunlight in high and low photovoltaic concentration

    International Nuclear Information System (INIS)

    Leutz, Ralf

    2014-01-01

    A simple model incorporating linear radiation characteristics, along with the optical trains and geometrical concentration ratios of solar concentrators is presented with performance examples for optical trains of HCPV, LCPV and benchmark flat-plate PV

  18. Metamaterial Receivers for High Efficiency Concentrated Solar Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Yellowhair, Julius E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Technologies Dept.; Kwon, Hoyeong [Univ. of Texas, Austin, TX (United States). Dept. of Electrical and Computer Engineering; Alu, Andrea [Univ. of Texas, Austin, TX (United States). Dept. of Electrical and Computer Engineering; Jarecki, Robert L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Technologies Dept.; Shinde, Subhash L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Technologies Dept.

    2016-09-01

    Operation of concentrated solar power receivers at higher temperatures (>700°C) would enable supercritical carbon dioxide (sCO2) power cycles for improved power cycle efficiencies (>50%) and cost-effective solar thermal power. Unfortunately, radiative losses at higher temperatures in conventional receivers can negatively impact the system efficiency gains. One approach to improve receiver thermal efficiency is to utilize selective coatings that enhance absorption across the visible solar spectrum while minimizing emission in the infrared to reduce radiative losses. Existing coatings, however, tend to degrade rapidly at elevated temperatures. In this report, we report on the initial designs and fabrication of spectrally selective metamaterial-based absorbers for high-temperature, high-thermal flux environments important for solarized sCO2 power cycles. Metamaterials are structured media whose optical properties are determined by sub-wavelength structural features instead of bulk material properties, providing unique solutions by decoupling the optical absorption spectrum from thermal stability requirements. The key enabling innovative concept proposed is the use of structured surfaces with spectral responses that can be tailored to optimize the absorption and retention of solar energy for a given temperature range. In this initial study through the Academic Alliance partnership with University of Texas at Austin, we use Tungsten for its stability in expected harsh environments, compatibility with microfabrication techniques, and required optical performance. Our goal is to tailor the optical properties for high (near unity) absorptivity across the majority of the solar spectrum and over a broad range of incidence angles, and at the same time achieve negligible absorptivity in the near infrared to optimize the energy absorbed and retained. To this goal, we apply the recently developed concept of plasmonic Brewster angle to suitably designed

  19. Alcoholic fermentation by immobilized yeast at high sugar concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Holcberg, I.B.; Margalith, P.

    1981-01-01

    Glucose fermentation by Saccharomyces cerevisiae immobilized by entrapment in agar, carrageenan, alginate and polyacrylamide gels, was compared to that of freely suspended cells at concentration of 10-50% (w.w.) sugar. The rate of ethanol production by the entrapped cells was 20-25% higher than that of the free cells. Concentrations of up to 14.5% w/w ethanol (30% glucose initial concentration) could be obtained. A number of hypotheses for the improved alcoholic fermentation are discussed.

  20. Cylindrically symmetric Fresnel lens for high concentration photovoltaic

    Science.gov (United States)

    Hung, Yu-Ting; Su, Guo-Dung

    2009-08-01

    High concentration photovoltaic (HCPV) utilizes point-focus cost-effective plastic Fresnel lens. And a millimeter-sized Ill-V compound multi-junction solar cell is placed underneath focusing optics which can achieve cell efficiency potential of up to 40.7 %. The advantage of HCPV makes less solar cell area and higher efficiency; however, the acceptance angle of HCPV is about +/-1°, which is very small and the mechanical tracking of the sun is necessary. In order to reduce the power consumption and the angle tracking error of tracking systems, a light collector model with larger acceptance angle is designed with ZEMAX®. In this model, the original radially symmetric Fresnel lens of HCPV is replaced by cylindrically symmetric Fresnel lens and a parabolic reflective surface. Light is collected in two dimensions separately. And a couple of lenses and a light pipe are added before the solar cell chip in order to collect more light when sun light deviates from incident angle of 00. An acceptance angle of +/-10° is achieved with GCR 400.

  1. Selection of common bean lines with high grain yield and high grain calcium and iron concentrations

    Directory of Open Access Journals (Sweden)

    Nerinéia Dalfollo Ribeiro

    2014-02-01

    Full Text Available Genetic improvement of common bean nutritional quality has advantages in marketing and can contribute to society as a food source. The objective of this study was to evaluate the genetic variability for grain yield, calcium and iron concentrations in grains of inbred common bean lines obtained by different breeding methods. For this, 136 F7 inbred lines were obtained using the Pedigree method and 136 F7 inbred lines were obtained using the Single-Seed Descent (SSD method. The lines showed genetic variability for grain yield, and concentrations of calcium and iron independently of the method of advancing segregating populations. The Pedigree method allows obtaining a greater number of lines with high grain yield. Selection using the SSD method allows the identification of a larger number of lines with high concentrations of calcium and iron in grains. Weak negative correlations were found between grain yield and calcium concentration (r = -0.0994 and grain yield and iron concentration (r = -0.3926. Several lines show genetic superiority for grain yield and concentrations of calcium and iron in grains and their selection can result in new common bean cultivars with high nutritional quality.

  2. An Automatic High Efficient Method for Dish Concentrator Alignment

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2014-01-01

    for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our method.

  3. Starch source in high concentrate rations does not affect rumen pH, histamine and lipopolysaccharide concentrations in dairy cows

    NARCIS (Netherlands)

    Pilachai, R.; Schonewille, J.T.; Thamrongyoswittayakul, C.; Aiumlamai, S.; Wachirapakom, C.; Everts, H.; Hendriks, W.H.

    2012-01-01

    The replacement of ground corn by cassava meal on rumen pH, lipopolysaccharide (LPS) and histamine concentrations under typical Thai feeding conditions (high concentrate diets and rice straw as the sole source of roughage) was investigated. Four rumen-fistulated crossbred Holstein, non-pregnant, dry

  4. A high-gain, compact, nonimaging concentrator: RXI.

    Science.gov (United States)

    Miñano, J C; Gonźlez, J C; Benítez, P

    1995-12-01

    The design procedure of a new nonimaging concentrator (called an RXI) is explained. Rays that impinge on the concentrator aperture, within the acceptance angle, are directed to the receiver by means of one refraction, one reflection, and one total internal reflection. The concentrator can be made as a single dielectric piece (in which the receiver is immersed) whose aspect ratio (thickness/aperture diameter) is close to 1/3. Ray-tracing analysis of a rotational symmetric RXI shows total transmissions of greater than 94.5% (no absorption or reflection losses are considered) when the acceptance angle of the incoming rays is small (<3°) and when the receiver area is the smallest possible (maximal concentration.).

  5. Intercomparison of passive microwave sea ice concentration retrievals over the high-concentration Arctic sea ice

    DEFF Research Database (Denmark)

    andersen, susanne; Tonboe, R.; Kaleschke, L.

    2007-01-01

    [1] Measurements of sea ice concentration from the Special Sensor Microwave Imager (SSM/I) using seven different algorithms are compared to ship observations, sea ice divergence estimates from the Radarsat Geophysical Processor System, and ice and water surface type classification of 59 wide...... with sensor noise between 1.3 and 1.8%. This is in accord with variability estimated from analysis of SSM/I time series. Algorithms, which primarily use 85 GHz information, consistently give the best agreement with both SAR ice concentrations and ship observations. Although the 85 GHz information is more...... sensitive to atmospheric influences, it was found that the atmospheric contribution is secondary to the influence of the surface emissivity variability. Analysis of the entire SSM/I time series shows that there are significant differences in trend between sea ice extent and area, using different algorithms...

  6. Efficacy of high iodine concentration contrast medium with saline pushing in hepatic CT in patients with chronic liver disease. Comparison of high doses-standard contrast medium concentration

    International Nuclear Information System (INIS)

    Matoba, Munetaka; Kondo, Tamaki; Nishikawa, Takahiro; Kuginuki, Yasuaki; Yokota, Hajime; Higashi, Kotaro; Tonami, Hisao

    2006-01-01

    The aim of this study was to compare the enhancement of liver parenchyama with high iodine concentration contrast medium with saline pushing to that with high doses standard iodine concentration in hepatic CT in patients with chronic liver disease. There was no statistically significant difference regarding to the enhancement of liver parenchyama between the 370 mgI/ml of contrast medium with saline pushing and high doses standard iodine concentration contrast medium. (author)

  7. Hyperpolarized metabolic MR in the study of cardiac function and disease

    DEFF Research Database (Denmark)

    Lauritzen, M. H.; Søgaard, L. V.; Madsen, Pia Lisbeth

    2014-01-01

    Several diseases of the heart have been linked to an insufficient ability to generate enough energy (ATP) to sustain proper heart function. Hyperpolarized magnetic resonance (MR) is a novel technique that can visualize and quantify myocardial energy metabolism. Hyperpolarization enhances the MR...... signal from a biological molecule of interest by more than 10,000 times, making it possible to measure its cellular uptake and conversion in specific enzymatic pathways in real time. We review the role of hyperpolarized MR in identifying changes in cardiac metabolism in vivo, and present the extensive...... literature on hyperpolarized pyruvate that has been used to characterize cardiac disease in various in vivo models, such as myocardial ischemia, hypertension, diabetes, hyperthyroidism and heart failure. The technical aspects of the technique are presented as well as the challenges of translating...

  8. Hyperpolarized Water Perfusion in the Porcine Brain – a Pilot Study

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Lipsø, Hans Kasper Wigh; Tougaard, Rasmus Stilling

    2017-01-01

    Dynamic Contrast-Enhanced MR (DCE-MR) perfusion assessment with gadolinium contrast agents is currently the most widely used cerebral perfusion MR method. Hyperpolarized water has recently been shown to succeed 13C probes as angiography probe. In this study, we demonstrate the feasibility...... of hyperpolarized water for visualizing the brain vasculature of a large animal in a clinically relevant setting. In detail, reference perfusion values were obtained and large to small arteries could be identified....

  9. Renal MR angiography and perfusion in the pig using hyperpolarized water

    DEFF Research Database (Denmark)

    Lipsø, Hans Kasper Wigh; Hansen, Esben Søvsø Szocska; Tougaard, Rasmus Stilling

    2016-01-01

    at 3 Tesla (T). Approximately 15 mL of hyperpolar-ized water was injected in the renal artery by hand over 4–5 s.Results: A liquid state polarization of 5.3 6 0.9% of 3.8 M pro-tons in 15 mL of deuterium oxide was achieved with a T1of24 6 1 s. This allowed injection through an arterial catheterinto...

  10. Hyperpolarized [U-(2) H, U-(13) C]Glucose reports on glycolytic and pentose phosphate pathway activity in EL4 tumors and glycolytic activity in yeast cells.

    Science.gov (United States)

    Timm, Kerstin N; Hartl, Johannes; Keller, Markus A; Hu, De-En; Kettunen, Mikko I; Rodrigues, Tiago B; Ralser, Markus; Brindle, Kevin M

    2015-12-01

    A resonance at ∼181 ppm in the (13) C spectra of tumors injected with hyperpolarized [U-(2) H, U-(13) C]glucose was assigned to 6-phosphogluconate (6PG), as in previous studies in yeast, whereas in breast cancer cells in vitro this resonance was assigned to 3-phosphoglycerate (3PG). These peak assignments were investigated here using measurements of 6PG and 3PG (13) C-labeling using liquid chromatography tandem mass spectrometry (LC-MS/MS) METHODS: Tumor-bearing mice were injected with (13) C6 glucose and the (13) C-labeled and total 6PG and 3PG concentrations measured. (13) C MR spectra of glucose-6-phosphate dehydrogenase deficient (zwf1Δ) and wild-type yeast were acquired following addition of hyperpolarized [U-(2) H, U-(13) C]glucose and again (13) C-labeled and total 6PG and 3PG were measured by LC-MS/MS RESULTS: Tumor (13) C-6PG was more abundant than (13) C-2PG/3PG and the resonance at ∼181 ppm matched more closely that of 6PG. (13) C MR spectra of wild-type and zwf1Δ yeast cells showed a resonance at ∼181 ppm after labeling with hyperpolarized [U-(2) H, U-(13) C]glucose, however, there was no 6PG in zwf1Δ cells. In the wild-type cells 3PG was approximately four-fold more abundant than 6PG CONCLUSION: The resonance at ∼181 ppm in (13) C MR spectra following injection of hyperpolarized [U-(2) H, U-(13) C]glucose originates predominantly from 6PG in EL4 tumors and 3PG in yeast cells. © 2014 Wiley Periodicals, Inc.

  11. Highly Sensitive Cadmium Concentration Sensor Using Long Period Grating

    Directory of Open Access Journals (Sweden)

    A. S. Lalasangi

    2011-08-01

    Full Text Available In this paper we have proposed a simple and effective Long Period Grating chemical sensor for detecting the traces of Cadmium (Cd++ in drinking water at ppm level. Long Period gratings (LPG were fabricated by point-by-point technique with CO2 laser. We have characterized the LPG concentration sensor sensitivity for different solutions of Cd concentrations varying from 0.01 ppm to 0.04 ppm by injecting white Light source and observed transmitted spectra using Optical Spectrum Analyzer (OSA. Proper reagents have been used in the solutions for detection of the Cd species. The overall shift in wavelength is 10 nm when surrounding medium gradually changed from water to 0.04 ppm of cadmium concentrations. A comparative study has been done using sophisticated spectroscopic atomic absorption spectrometer (AAS and Inductively Coupled Plasma (ICP instruments. The spectral sensitivity enhancement was done by modifying grating surface with gold nanoparticles.

  12. Carbon dioxide concentrations are very high in developing oilseeds.

    Science.gov (United States)

    Goffman, Fernando D; Ruckle, Mike; Ohlrogge, John; Shachar-Hill, Yair

    2004-09-01

    A new method has been developed to rapidly determine the total inorganic carbon concentration (gaseous [CO2] + aqueous [CO(2)] + [HCO3-] + [CO3(2)-]) in developing seeds. Seeds are rapidly dissected and homogenized in 1 N HCl in gas-tight vials. The headspace gas is then analyzed by infrared gas analysis. Developing rapeseed (Brassica napus L.) and soybean [Glycine max (L.) Merr.] seeds were analyzed and found to have up to 40 and 12 mM total inorganic carbon, respectively. These concentrations are ca. 600-2000-fold higher than in ambient air or values reported for leaves. Carbon dioxide concentrations in rapeseed peaked during the stage of maximum oil synthesis and declined as seeds matured. The consequences for seed metabolism, physiology and carbon economy are discussed.

  13. The obtaining a high-grade gadolinium concentrate

    International Nuclear Information System (INIS)

    Soltysiak, I.; Ozga, W.

    1982-01-01

    Gadolinium concentrates obtained by the fractional precipitation of lanthanon-potassium double chromates were separated by ion exchange with 0,4 M lactic acid solution in the presence of 0,1 M ammonium nitrate at pH of the medium 2,95-3,4. It was found out, that using the fractional precipitation of lanthanon-potassium double chromates (as the fast and cheap method that does not need special equipment) together with ion exchange separation with lactic acid solution as the eluent gave a highgrade gadolinium concentrate in a quick and economical way. (author)

  14. Passive shimming of the fringe field of a superconducting magnet for ultra-low field hyperpolarized noble gas MRI.

    Science.gov (United States)

    Parra-Robles, Juan; Cross, Albert R; Santyr, Giles E

    2005-05-01

    Hyperpolarized noble gases (HNGs) provide exciting possibilities for MR imaging at ultra-low magnetic field strengths (superconductive magnets used in clinical MR imaging can provide a stable magnetic field for this purpose. In addition to offering the benefit of HNG MR imaging alongside conventional high field proton MRI, this approach offers the other useful advantage of providing different field strengths at different distances from the magnet. However, the extremely strong field gradients associated with the fringe field present a major challenge for imaging since impractically high active shim currents would be required to achieve the necessary homogeneity. In this work, a simple passive shimming method based on the placement of a small number of ferromagnetic pieces is proposed to reduce the fringe field inhomogeneities to a level that can be corrected using standard active shims. The method explicitly takes into account the strong variations of the field over the volume of the ferromagnetic pieces used to shim. The method is used to obtain spectra in the fringe field of a high-field (1.89 T) superconducting magnet from hyperpolarized 129Xe gas samples at two different ultra-low field strengths (8.5 and 17 mT). The linewidths of spectra measured from imaging phantoms (30 Hz) indicate a homogeneity sufficient for MRI of the rat lung.

  15. Stability of Human Telomere Quadruplexes at High DNA Concentrations

    Czech Academy of Sciences Publication Activity Database

    Kejnovská, Iva; Vorlíčková, Michaela; Brázdová, Marie; Sagi, J.

    2014-01-01

    Roč. 101, č. 4 (2014), s. 428-438 ISSN 0006-3525 R&D Projects: GA ČR(CZ) GAP205/12/0466 Institutional support: RVO:68081707 Keywords : quadruplex * DNA concentration * folding topology Subject RIV: BO - Biophysics Impact factor: 2.385, year: 2014

  16. High concentrations of natural rubber latex allergens in gloves used ...

    African Journals Online (AJOL)

    Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported. Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a ...

  17. Quantitative chemical exchange saturation transfer with hyperpolarized nuclei (qHyper-CEST): sensing xenon-host exchange dynamics and binding affinities by NMR.

    Science.gov (United States)

    Kunth, M; Witte, C; Schröder, L

    2014-11-21

    The reversible binding of xenon to host molecules has found numerous applications in nuclear magnetic resonance studies. Quantitative characterization of the Xe exchange dynamics is important to understand and optimize the physico-chemical behavior of such Xe hosts, but is often challenging to achieve at low host concentrations. We have investigated a sensitive quantification technique based on chemical exchange saturation transfer with hyperpolarized nuclei, qHyper-CEST. Using simulated signals we demonstrated that qHyper-CEST yielded accurate and precise results and was robust in the presence of large amounts of noise (10%). This is of particular importance for samples with completely unknown exchange rates. Using these findings we experimentally determined the following exchange parameters for the Xe host cryptophane-A monoacid in dimethyl sulfoxide in one type of experiment: the ratio of bound and free Xe, the Xe exchange rate, the resonance frequencies of free and bound Xe, the Xe host occupancy, and the Xe binding constant. Taken together, qHyper-CEST facilitates sensitive quantification of the Xe exchange dynamics and binding to hydrophobic cavities and has the potential to analyze many different host systems or binding sites. This makes qHyper-CEST an indispensable tool for the efficient design of highly specific biosensors.

  18. High concentrations of pepsin in bronchoalveolar lavage fluid from children with cystic fibrosis are associated with high interleukin-8 concentrations.

    LENUS (Irish Health Repository)

    McNally, P

    2012-02-01

    BACKGROUND: Gastro-oesophageal reflux is common in children with cystic fibrosis (CF) and is thought to be associated with pulmonary aspiration of gastric contents. The measurement of pepsin in bronchoalveolar lavage (BAL) fluid has recently been suggested to be a reliable indicator of aspiration. The prevalence of pulmonary aspiration in a group of children with CF was assessed and its association with lung inflammation investigated. METHODS: This was a cross-sectional case-control study. BAL fluid was collected from individuals with CF (n=31) and healthy controls (n=7). Interleukin-8 (IL-8), pepsin, neutrophil numbers and neutrophil elastase activity levels were measured in all samples. Clinical, microbiological and lung function data were collected from medical notes. RESULTS: The pepsin concentration in BAL fluid was higher in the CF group than in controls (mean (SD) 24.4 (27.4) ng\\/ml vs 4.3 (4.0) ng\\/ml, p=0.03). Those with CF who had raised pepsin concentrations had higher levels of IL-8 in the BAL fluid than those with a concentration comparable to controls (3.7 (2.7) ng\\/ml vs 1.4 (0.9) ng\\/ml, p=0.004). Within the CF group there was a moderate positive correlation between pepsin concentration and IL-8 in BAL fluid (r=0.48, p=0.04). There was no association between BAL fluid pepsin concentrations and age, sex, body mass index z score, forced expiratory volume in 1 s or Pseudomonas aeruginosa colonisation status. CONCLUSIONS: Many children with CF have increased levels of pepsin in the BAL fluid compared with normal controls. Increased pepsin levels were associated with higher IL-8 concentrations in BAL fluid. These data suggest that aspiration of gastric contents occurs in a subset of patients with CF and is associated with more pronounced lung inflammation.

  19. High pressure inertial focusing for separating and concentrating bacteria at high throughput

    Science.gov (United States)

    Cruz, J.; Hooshmand Zadeh, S.; Graells, T.; Andersson, M.; Malmström, J.; Wu, Z. G.; Hjort, K.

    2017-08-01

    Inertial focusing is a promising microfluidic technology for concentration and separation of particles by size. However, there is a strong correlation of increased pressure with decreased particle size. Theory and experimental results for larger particles were used to scale down the phenomenon and find the conditions that focus 1 µm particles. High pressure experiments in robust glass chips were used to demonstrate the alignment. We show how the technique works for 1 µm spherical polystyrene particles and for Escherichia coli, not being harmful for the bacteria at 50 µl min-1. The potential to focus bacteria, simplicity of use and high throughput make this technology interesting for healthcare applications, where concentration and purification of a sample may be required as an initial step.

  20. X-radiation effect on the hyperpolarization of cells, the adeninenucleotide content and the distribution of sodium and potassium ions

    Energy Technology Data Exchange (ETDEWEB)

    Frol' kis, V V [Akademiya Meditsinskikh Nauk Ukrainskoj SSR, Kiev. Inst. Gerontologii

    1975-03-01

    X-radiation prevents the progress of hyperpolarization of muscle and liver cells caused by hormones (estradioldipropyonate, deoxycorticosteron-acetate and insulin) and by the loss of blood. X-radiation offsets the redistribution of K/sup +/ and Na/sup +/ ions caused by hyperpolarization and does not change the level of ATP, ADP, CP and Pi. X-radiation is suggested to affect the hyperpolarization and the ionic shifts via the system of protein biosynthesis.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  3. Pathway to cryogen free production of hyperpolarized Krypton-83 and Xenon-129.

    Directory of Open Access Journals (Sweden)

    Joseph S Six

    Full Text Available Hyperpolarized (hp (129Xe and hp (83Kr for magnetic resonance imaging (MRI are typically obtained through spin-exchange optical pumping (SEOP in gas mixtures with dilute concentrations of the respective noble gas. The usage of dilute noble gases mixtures requires cryogenic gas separation after SEOP, a step that makes clinical and preclinical applications of hp (129Xe MRI cumbersome. For hp (83Kr MRI, cryogenic concentration is not practical due to depolarization that is caused by quadrupolar relaxation in the condensed phase. In this work, the concept of stopped flow SEOP with concentrated noble gas mixtures at low pressures was explored using a laser with 23.3 W of output power and 0.25 nm linewidth. For (129Xe SEOP without cryogenic separation, the highest obtained MR signal intensity from the hp xenon-nitrogen gas mixture was equivalent to that arising from 15.5±1.9% spin polarized (129Xe in pure xenon gas. The production rate of the hp gas mixture, measured at 298 K, was 1.8 cm(3/min. For hp (83Kr, the equivalent of 4.4±0.5% spin polarization in pure krypton at a production rate of 2 cm(3/min was produced. The general dependency of spin polarization upon gas pressure obtained in stopped flow SEOP is reported for various noble gas concentrations. Aspects of SEOP specific to the two noble gas isotopes are discussed and compared with current theoretical opinions. A non-linear pressure broadening of the Rb D(1 transition was observed and taken into account for the qualitative description of the SEOP process.

  4. Pathway to cryogen free production of hyperpolarized Krypton-83 and Xenon-129.

    Science.gov (United States)

    Six, Joseph S; Hughes-Riley, Theodore; Stupic, Karl F; Pavlovskaya, Galina E; Meersmann, Thomas

    2012-01-01

    Hyperpolarized (hp) (129)Xe and hp (83)Kr for magnetic resonance imaging (MRI) are typically obtained through spin-exchange optical pumping (SEOP) in gas mixtures with dilute concentrations of the respective noble gas. The usage of dilute noble gases mixtures requires cryogenic gas separation after SEOP, a step that makes clinical and preclinical applications of hp (129)Xe MRI cumbersome. For hp (83)Kr MRI, cryogenic concentration is not practical due to depolarization that is caused by quadrupolar relaxation in the condensed phase. In this work, the concept of stopped flow SEOP with concentrated noble gas mixtures at low pressures was explored using a laser with 23.3 W of output power and 0.25 nm linewidth. For (129)Xe SEOP without cryogenic separation, the highest obtained MR signal intensity from the hp xenon-nitrogen gas mixture was equivalent to that arising from 15.5±1.9% spin polarized (129)Xe in pure xenon gas. The production rate of the hp gas mixture, measured at 298 K, was 1.8 cm(3)/min. For hp (83)Kr, the equivalent of 4.4±0.5% spin polarization in pure krypton at a production rate of 2 cm(3)/min was produced. The general dependency of spin polarization upon gas pressure obtained in stopped flow SEOP is reported for various noble gas concentrations. Aspects of SEOP specific to the two noble gas isotopes are discussed and compared with current theoretical opinions. A non-linear pressure broadening of the Rb D(1) transition was observed and taken into account for the qualitative description of the SEOP process.

  5. Validating excised rodent lungs for functional hyperpolarized xenon-129 MRI.

    Directory of Open Access Journals (Sweden)

    David M L Lilburn

    Full Text Available Ex vivo rodent lung models are explored for physiological measurements of respiratory function with hyperpolarized (hp (129Xe MRI. It is shown that excised lung models allow for simplification of the technical challenges involved and provide valuable physiological insights that are not feasible using in vivo MRI protocols. A custom designed breathing apparatus enables MR images of gas distribution on increasing ventilation volumes of actively inhaled hp (129Xe. Straightforward hp (129Xe MRI protocols provide residual lung volume (RV data and permit for spatially resolved tracking of small hp (129Xe probe volumes during the inhalation cycle. Hp (129Xe MRI of lung function in the excised organ demonstrates the persistence of post mortem airway responsiveness to intravenous methacholine challenges. The presented methodology enables physiology of lung function in health and disease without additional regulatory approval requirements and reduces the technical and logistical challenges with hp gas MRI experiments. The post mortem lung functional data can augment histological measurements and should be of interest for drug development studies.

  6. Spontaneous deswelling of pNIPAM microgels at high concentrations

    Science.gov (United States)

    Gasser, Urs; Scotti, Andrea; Herman, Emily S.; Pelaez-Fernandez, Miguel; Han, Jun; Menzel, Andreas; Lyon, L. Andrew; Fernandez-Nieves, Alberto

    Polydisperse suspensions of pNIPAM microgel particles show a unique, spontaneous particle deswelling behavior. Beyond a critical concentration, the largest microgels deswell and thereby reduce the polydispersity of the suspension. We have recently unraveled the mechanism of this spontaneous, selective deswelling. pNIPAM microgels carry charged sulfate groups originating from the ammonium persulfate starter used in particle synthesis. Most of the ammonium counterions are trapped close to the microgel surface, but a fraction of them escapes the electrostatic attraction and contributes to the osmotic pressure of the suspension. The counterion clouds of neighboring particles progressively overlap with increasing volume fraction, leading to an increase of free counterions and the osmotic pressure outside but not inside the microgel particles. We find particles to deswell when the resulting osmotic pressure difference between the inside and the outside becomes larger their bulk modulus. For pNIPAM microgels synthesized with the same protocol, the largest particles are the softest and deswell first.

  7. High Concentration Protein Ultrafiltration: a Comparative Fouling Assessment

    Science.gov (United States)

    Lim, Y. P.; Mohammad, A. W.

    2018-05-01

    In this paper, the predominant fouling mechanism via pH manipulation in gelatin ultrafiltration (UF) at constant operating pressure was studied. Two 30 kDa molecular weight cut off (MWCO) UF membranes with different hydrophilic/hydrophobic properties were tested at solution pH near gelatin isoelectric point (IEP), pH below and above gelatin’s IEP. The resistance-in-series model was used to determine quantitatively the contribution of each filtration resistance occurred during gelatin UF. The governing fouling mechanisms were investigated using classical blocking laws. The results demonstrated that concentration polarization remain as dominant fouling resistance in gelatin UF, but exceptional case was observed at pH away from gelatin’s IEP, showing that combined reversible and irreversible fouling resistances contributed around 57% and 37%, respectively to the overall fouling resistances. Under all experimental condition tested, permeate flux decline was accurately predicted by all the models studied. Fouling profile was fitted well with “Standard Blocking”, “Intermediate Blocking” and “Cake Filtration” model for regenerated cellulose acetate (RCA) membrane and “Cake Filtration” model for polyethersulphone (PES) membrane.

  8. Adaptive sensor-based ultra-high accuracy solar concentrator tracker

    Science.gov (United States)

    Brinkley, Jordyn; Hassanzadeh, Ali

    2017-09-01

    Conventional solar trackers use information of the sun's position, either by direct sensing or by GPS. Our method uses the shading of the receiver. This, coupled with nonimaging optics design allows us to achieve ultra-high concentration. Incorporating a sensor based shadow tracking method with a two stage concentration solar hybrid parabolic trough allows the system to maintain high concentration with acute accuracy.

  9. Deep Sea Memory of High Atmospheric CO2 Concentration

    Science.gov (United States)

    Mathesius, Sabine; Hofmann, Matthias; Caldeira, Ken; Schellnhuber, Hans Joachim

    2015-04-01

    Carbon dioxide removal (CDR) from the atmosphere has been proposed as a powerful measure to mitigate global warming and ocean acidification. Planetary-scale interventions of that kind are often portrayed as "last-resort strategies", which need to weigh in if humankind keeps on enhancing the climate-system stock of CO2. Yet even if CDR could restore atmospheric CO2 to substantially lower concentrations, would it really qualify to undo the critical impacts of past emissions? In the study presented here, we employed an Earth System Model of Intermediate Complexity (EMIC) to investigate how CDR might erase the emissions legacy in the marine environment, focusing on pH, temperature and dissolved oxygen. Against a background of a world following the RCP8.5 emissions path ("business-as-usual") for centuries, we simulated the effects of two massive CDR interventions with CO2 extraction rates of 5 GtC yr-1 and 25 GtC yr-1, respectively, starting in 2250. We found that the 5 GtC yr-1 scheme would have only minor ameliorative influence on the oceans, even after several centuries of application. By way of contrast, the extreme 25 GtC yr-1 scheme eventually leads to tangible improvements. However, even with such an aggressive measure, past CO2 emissions leave a substantial legacy in the marine environment within the simulated period (i.e., until 2700). In summary, our study demonstrates that anthropogenic alterations of the oceans, caused by continued business-as-usual emissions, may not be reversed on a multi-centennial time scale by the most aspirational geoengineering measures. We also found that a transition from the RCP8.5 state to the state of a strong mitigation scenario (RCP2.6) is not possible, even under the assumption of extreme extraction rates (25 GtC yr-1). This is explicitly demonstrated by simulating additional scenarios, starting CDR already in 2150 and operating until the atmospheric CO2 concentration reaches 280 ppm and 180 ppm, respectively. The simulated

  10. High urinary phthalate concentration associated with delayed pubarche in girls

    DEFF Research Database (Denmark)

    Frederiksen, H; Sørensen, K; Mouritsen, A

    2012-01-01

    Phthalates are a group of chemicals present in numerous consumer products. They have anti-androgenic properties in experimental studies and are suspected to be involved in human male reproductive health problems. A few studies have shown associations between phthalate exposure and changes...... and controls. We demonstrated that delayed pubarche, but not thelarche, was associated with high phthalate excretion in urine samples from 725 healthy school girls, which may suggest anti-androgenic actions of phthalates in our study group of girls....

  11. High plasma uric acid concentration: causes and consequences

    Directory of Open Access Journals (Sweden)

    de Oliveira Erick

    2012-04-01

    Full Text Available Abstract High plasma uric acid (UA is a precipitating factor for gout and renal calculi as well as a strong risk factor for Metabolic Syndrome and cardiovascular disease. The main causes for higher plasma UA are either lower excretion, higher synthesis or both. Higher waist circumference and the BMI are associated with higher insulin resistance and leptin production, and both reduce uric acid excretion. The synthesis of fatty acids (tryglicerides in the liver is associated with the de novo synthesis of purine, accelerating UA production. The role played by diet on hyperuricemia has not yet been fully clarified, but high intake of fructose-rich industrialized food and high alcohol intake (particularly beer seem to influence uricemia. It is not known whether UA would be a causal factor or an antioxidant protective response. Most authors do not consider the UA as a risk factor, but presenting antioxidant function. UA contributes to > 50% of the antioxidant capacity of the blood. There is still no consensus if UA is a protective or a risk factor, however, it seems that acute elevation is a protective factor, whereas chronic elevation a risk for disease.

  12. Effects of pulmonary inhalation on hyperpolarized krypton-83 magnetic resonance T1 relaxation.

    Science.gov (United States)

    Stupic, K F; Elkins, N D; Pavlovskaya, G E; Repine, J E; Meersmann, T

    2011-07-07

    The (83)Kr magnetic resonance (MR) relaxation time T(1) of krypton gas in contact with model surfaces was previously found to be highly sensitive to surface composition, surface-to-volume ratio, and surface temperature. The work presented here explored aspects of pulmonary (83)Kr T(1) relaxation measurements in excised lungs from healthy rats using hyperpolarized (hp) (83)Kr with approximately 4.4% spin polarization. MR spectroscopy without spatial resolution was applied to the ex vivo lungs that actively inhale hp (83)Kr through a custom designed ventilation system. Various inhalation schemes were devised to study the influence of anatomical dead space upon the measured (83)Kr T(1) relaxation times. The longitudinal (83)Kr relaxation times in the distal airways and the respiratory zones were independent of the lung inhalation volume, with T(1) = 1.3 s and T(1) = 1.0 s, depending only on the applied inhalation scheme. The obtained data were highly reproducible between different specimens. Further, the (83)Kr T(1) relaxation times in excised lungs were unaffected by the presence of up to 40% oxygen in the hp gas mixture. The results support the possible importance of (83)Kr as a biomarker for evaluating lung function.

  13. High-order optical nonlinearities in nanocomposite films dispersed with semiconductor quantum dots at high concentrations

    International Nuclear Information System (INIS)

    Tomita, Yasuo; Matsushima, Shun-suke; Yamagami, Ryu-ichi; Jinzenji, Taka-aki; Sakuma, Shohei; Liu, Xiangming; Izuishi, Takuya; Shen, Qing

    2017-01-01

    We describe the nonlinear optical properties of inorganic-organic nanocomposite films in which semiconductor CdSe quantum dots as high as 6.8 vol.% are dispersed. Open/closed Z-scan measurements, degenerate multi-wave mixing and femtosecond pump-probe/transient grating measurements are conducted. It is shown that the observed fifth-order optical nonlinearity has the cascaded third-order contribution that becomes prominent at high concentrations of CdSe QDs. It is also shown that there are picosecond-scale intensity-dependent and nanosecond-scale intensity-independent decay components in absorptive and refractive nonlinearities. The former is caused by the Auger process, while the latter comes from the electron-hole recombination process. (paper)

  14. Quantification of human lung structure and physiology using hyperpolarized 129Xe.

    Science.gov (United States)

    Chang, Yulin V; Quirk, James D; Ruset, Iulian C; Atkinson, Jeffrey J; Hersman, F William; Woods, Jason C

    2014-01-01

    To present in vivo, human validation of a previously proposed method to measure key pulmonary parameters related to lung microstructure and physiology. Some parameters, such as blood-air barrier thickness, cannot be measured readily by any other noninvasive modality. Healthy volunteers (n = 12) were studied in 1.5T and 3T whole body human scanners using hyperpolarized xenon. Xenon uptake by lung parenchyma and blood was measured using a chemical shift saturation recovery sequence. Both dissolved-xenon peaks at 197 ppm and 217-218 ppm were fitted against a model of xenon exchange (MOXE) as functions of exchange time. Parameters related to lung function and structure can be obtained by fitting to this model. The following results were obtained from xenon uptake (averaged over all healthy volunteers): surface-area-to-volume ratio = 210 ± 50 cm(-1) ; total septal wall thickness = 9.2 ± 6.5 μm; blood-air barrier thickness = 1.0 ± 0.3 μm; hematocrit = 27 ± 4%; pulmonary capillary blood transit time = 1.3 ± 0.3 s, in good agreement with literature values from invasive experiments. More detailed fitting results are listed in the text. The initial in vivo human results demonstrate that our proposed methods can be used to noninvasively determine lung physiology by simultaneous quantification of a few important pulmonary parameters. This method is highly promising to become a versatile screening method for lung diseases. Copyright © 2013 Wiley Periodicals, Inc.

  15. Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material for ²⁹Si Magnetic Resonance Imaging.

    Science.gov (United States)

    Seo, Hyeonglim; Choi, Ikjang; Whiting, Nicholas; Hu, Jingzhe; Luu, Quy Son; Pudakalakatti, Shivanand; McCowan, Caitlin; Kim, Yaewon; Zacharias, Niki; Lee, Seunghyun; Bhattacharya, Pratip; Lee, Youngbok

    2018-05-20

    Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for ²⁹Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their ²⁹Si MR signals; the particles demonstrated long ²⁹Si spin-lattice relaxation (T₁) times (~ 25 mins), which suggests potential applicability for medical imaging. Furthermore, ²⁹Si hyperpolarization levels were sufficient to allow ²⁹Si MRI in phantoms. These results underscore the potential of porous silicon nanoparticles that, when combined with hyperpolarized magnetic resonance imaging, can be a powerful theragnostic deep tissue imaging platform to interrogate various biomolecular processes in vivo. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Modeling non-linear kinetics of hyperpolarized [1-(13)C] pyruvate in the crystalloid-perfused rat heart

    NARCIS (Netherlands)

    Mariotti, E.; Orton, M. R.; Eerbeek, O.; Ashruf, J. F.; Zuurbier, C. J.; Southworth, R.; Eykyn, T. R.

    2016-01-01

    Hyperpolarized (13)C MR measurements have the potential to display non-linear kinetics. We have developed an approach to describe possible non-first-order kinetics of hyperpolarized [1-(13)C] pyruvate employing a system of differential equations that agrees with the principle of conservation of mass

  17. Emulsifier development for high-concentrated reverse emulsions

    Directory of Open Access Journals (Sweden)

    I.L. Kovalenko

    2016-05-01

    Full Text Available The reverse emulsions have found broad application in ore mining industry as matrixes of emulsion explosive substances and boring washing waters. The defining characteristic of reverse emulsions of industrial explosive substances is the high stability and immunity to crystallization. Aim: The aim of this work is to assess the mechanism of emulsifiers effect like SMO and some PIBSA-derivatives, that are most abundantly used in world practice, and also to develop an effective domestic emulsifier of reverse emulsions. Materials and methods: Using the semi-dynamic method with use of the reverse stalagmometer it was determined the decreasing in interfacial tension on “water / diesel fuel” border in the presence of 0.5 wt % sorbitan monooleate of various producers. Emulsions with use of the chosen emulsifiers using the dynamic mixer on the basis of monosolution of ammonium nitrate and diesel fuel have been produced. The emulsions have the following composition, wt %: ammonium nitrate – 76.8; water – 15.6; diesel fuel – 6.0; emulsifier – 1.6. Results: By the researches results of the interfacial tension “surfactant water / solution in diesel fuel”, the stability of emulsions using monosolution of ammonium nitrate and the IR spectrums of SMO of various producers it is established that presence in product of impurity of oleic acid, di- and trioleates leads to decreasing in interphase activity, increasing of emulsifier oil solubility and decreasing the resistance of emulsions to crystallization. On the basis of the spectral data analysis it is suggested about possibility of specific interaction on the mechanism of “spectral resonance” between emulsifiers of the PIBSA-MEA, LZX type and crystals nucleus of NH4NO3 ammonium nitrate in dispersed phase of emulsion. Amidation of vegetable oils by monoethanol amine is implemented at the reduced temperatures (90…100 °C. It was proved the availability mainly of fatty acids amides in product

  18. MR imaging of the stomach and relaxation measurement with intraluminal hyperpolarized 129Xenon gas

    International Nuclear Information System (INIS)

    Yanagawa, Yasuhiro; Kimura, Atsuomi; Fujiwara, Hideaki; Kinoshita, Yoshimasa; Hattori, Mineyuki; Hiraga, Takashi; Iida, Hidehiro

    2001-01-01

    Using laser optical pumping, the nuclear spin polarization of noble gases can be strongly enhanced. The purpose of this study was to make a simple apparatus that can provide hyperpolarized 129 Xe gas, which can then be used in an attempt to obtain magnetic resonance imaging (MRI). We would also like to study the relaxation behavior of hyperpolarized 129 Xe gas through the measurement of the relaxation time. First, we demonstrated that hyperpolarized 129 Xe gas can be applied to magnetic resonance imaging of the stomach, by using a rat as a model. This was performed under a 4.7 T magnet field using the following imaging parameters for the hyperpolarized 129 Xe gas: TR=50 ms, TE=15 ms, FOV=10 x 10 cm 2 , matrix size 64 x 64, THK=2.54 cm. By using these parameters, we were able to obtain a hyperpolarized image of the stomach in rats for the first time. Next, we measured the relaxation times of the hyperpolarized 129 Xe gas enclosed in cavities such as the stomach of rats as well as in phantoms created by glass and gelatin bulbs. The cavity size dependency of the relaxation time was analyzed on the basis of the kinetic theory of gases. This analysis showed a linear relationship between the relaxation rate (1/T 1 ) and a square inverse of the cavity diameter (1/d 2 ). From this relationship, the wall effect on the 129 Xe relaxation can be estimated in the novel parameter t 1 , wall . This shows drastic dependency on the material of the wall, suggesting a potential use of the relaxation experiment as a diagnostic tool for organ surfaces in the future. (author)

  19. Hyperpolarization moves S4 sensors inward to open MVP, a methanococcal voltage-gated potassium channel.

    Science.gov (United States)

    Sesti, Federico; Rajan, Sindhu; Gonzalez-Colaso, Rosana; Nikolaeva, Natalia; Goldstein, Steve A N

    2003-04-01

    MVP, a Methanococcus jannaschii voltage-gated potassium channel, was cloned and shown to operate in eukaryotic and prokaryotic cells. Like pacemaker channels, MVP opens on hyperpolarization using S4 voltage sensors like those in classical channels activated by depolarization. The MVP S4 span resembles classical sensors in sequence, charge, topology and movement, traveling inward on hyperpolarization and outward on depolarization (via canaliculi in the protein that bring the extracellular and internal solutions into proximity across a short barrier). Thus, MVP opens with sensors inward indicating a reversal of S4 position and pore state compared to classical channels. Homologous channels in mammals and plants are expected to function similarly.

  20. In vivo assessment of intracellular redox state in rat liver using hyperpolarized [1-13 C]Alanine.

    Science.gov (United States)

    Park, Jae Mo; Khemtong, Chalermchai; Liu, Shie-Chau; Hurd, Ralph E; Spielman, Daniel M

    2017-05-01

    The intracellular lactate to pyruvate concentration ratio is a commonly used tissue assay biomarker of redox, being proportional to free cytosolic [NADH]/[NAD + ]. In this study, we assessed the use of hyperpolarized [1- 13 C]alanine and the subsequent detection of the intracellular products of [1- 13 C]pyruvate and [1- 13 C]lactate as a useful substrate for assessing redox levels in the liver in vivo. Animal experiments were conducted to measure in vivo metabolism at baseline and after ethanol infusion. A solution of 80-mM hyperpolarized [1- 13 C]alanine was injected intravenously at baseline (n = 8) and 45 min after ethanol infusion (n = 4), immediately followed by the dynamic acquisition of 13 C MRS spectra. In vivo rat liver spectra showed peaks from [1- 13 C] alanine and the products of [1- 13 C]lactate, [1- 13 C]pyruvate, and 13 C-bicarbonate. A significantly increased 13 C-lactate/ 13 C-pyruvate ratio was observed after ethanol infusion (8.46 ± 0.58 at baseline versus 13.58 ± 0.69 after ethanol infusion; P alanine is presented, with the validity of the proposed 13 C-pyruvate/ 13 C-lactate metric tested using an ethanol challenge to alter liver redox state. Magn Reson Med 77:1741-1748, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  1. Physical interactions of hyperpolarized gas in the lung

    Science.gov (United States)

    Chen, Xiu-Hao Josette

    1999-09-01

    This thesis addresses key interactions of hyperpolarized (HP) gas within the biological environment of the lung using magnetic resonance imaging (MRI). The first excised lung image was obtained in 1994 by Albert et al ., indicating the relative youth of the HP gas MRI field. Thus, there are a multitude of parameters which need to be explored to optimize contrast mechanisms and pulse sequences for in vivo applications. To perform HP gas MRI, both the production of HP gas and development of appropriate MRI pulse sequences were necessary. The apparatus for gas polarization was transferred from Princeton University, then modified and optimized to provide larger quantities and higher polarizations. It was ultimately replaced by a prototype commercial apparatus. Existing MRI pulse sequences were changed to accommodate and exploit the unique situation of non-equilibrium polarized gas. Several physical parameters of the gas relating to structure and function in the lung were investigated. It was found that using a range of excitation powers, acquisition windows, and ventilatory cycle segments yielded dramatically different types of images in the guinea pig. Spatially localized lineshapes of HP 3He showed differentiated peaks (corresponding to frequency shifts) which represent gas in major airways (2 ppm) and alveoli (1-2 ppm). Quantitative maps of the diffusion coefficient (D) showed evidence of free diffusion in the trachea (average of 2.4 cm2/s for 3He and 0.68 cm2/s for 129Xe) and restricted diffusion combined with effects of gas mixtures in the distal pulmonary airspaces (average of 0.16 cm2/s for 3He and 0.021 cm2/s for 129Xe). Experimental measurements were verified with gas mixture and porous media theory for both 3He and 129Xe. The dephasing parameter, T*2 , was mapped showing sensitivity to changes in tidal volume and oxygen level. The T*2 values ranged from 9.2 to 15.9 ms in the intrapulmonary airspaces depending on the breathing paradigm. Experimental results

  2. Characterization and flip angle calibration of 13C surface coils for hyperpolarization studies

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Gutte, Henrik; Larsen, Majbrit M E

    The aim of the present work is to address the challenge of optimal The aim of the present work is to address the challenge of optimal flflip angle calibration of ip angle calibration of C surface coils in C surface coils in hyperpolarization studies. To this end, we characterize the spatial pro h...

  3. Role of endothelium-derived hyperpolarization in the vasodilatation of rat intrarenal arteries

    DEFF Research Database (Denmark)

    Pinilla, Estéfano; Sánchez-Pina, Ana; Muñoz Picos, Mercedes

    2016-01-01

    Background and purpose: Endothelium-dependent vasodilation plays an important role in the regulation of vascular tone in different vascular beds. Besides the release of prostacyclin (PGI2) and nitric oxide (NO), the endothelium mediates vasodilation through endothelium-derived hyperpolarization (...

  4. Irreversible Catalyst Activation Enables Hyperpolarization and Water Solubility for NMR Signal Amplification by Reversible Exchange

    Science.gov (United States)

    2016-09-12

    G. R.; Duckett, S. B.; Spiess , H. W.; Schreiber, L. M.; Münnemann, K. Continuous Proton Hyperpolarization Via SABRE and Hollow Fibre Membranes. Proc...M.; Kindervater, P.; Raich, H.-P.; Bargon, J.; Spiess , H. W.; Muennemann, K. Continuous H-1 and C-13 Signal Enhancement in NMR Spectroscopy and MRI

  5. Phase dependency of electrotonic spread of hyperpolarizing current pulses in the rabbit sinoatrial node

    NARCIS (Netherlands)

    Duivenvoorden, J. J.; Bouman, L. N.; Bukauskas, F. F.; Opthof, T.; Jongsma, H. J.

    1990-01-01

    Electrotonic current spread in the SA node of the rabbit was measured by means of hyperpolarizing current pulses (1 to 10 microA, 60 ms), which were injected intracellularly through a K(+)-perfused suction electrode. The pulses were applied at the beginning, middle or end of the diastolic

  6. Hyperpolarized 3-helium MR imaging of the lungs: testing the concept of a central production facility

    International Nuclear Information System (INIS)

    Beek, E.J.R. van; Schmiedeskamp, J.; Filbir, F.; Heil, W.; Wolf, M.; Otten, E.; Wild, J.M.; Paley, M.N.J.; Fichele, S.; Woodhouse, N.; Swift, A.; Knitz, F.; Mills, G.H.

    2003-01-01

    The aim of this study was to test the feasibility of a central production facility with distribution network for implementation of hyperpolarized 3-helium MRI. The 3-helium was hyperpolarized to 50-65% using a large-scale production facility based at a university in Germany. Using a specially designed transport box, containing a permanent low-field shielded magnet and dedicated iron-free glass cells, the hyperpolarized 3-helium gas was transported via airfreight to a university in the UK. At this location, the gas was used to perform in vivo MR experiments in normal volunteers and patients with chronic obstructive lung diseases. Following initial tests, the transport (road-air-road cargo) was successfully arranged on six occasions (approximately once per month). The duration of transport to imaging averaged 18 h (range 16-20 h), which was due mainly to organizational issues such as working times and flight connections. During the course of the project, polarization at imaging increased from 20% to more than 30%. A total of 4 healthy volunteers and 8 patients with chronic obstructive pulmonary disease were imaged. The feasibility of a central production facility for hyperpolarized 3-helium was demonstrated. This should enable a wider distribution of gas for this novel technology without the need for local start-up costs. (orig.)

  7. Synthesis of long T silicon nanoparticles for hyperpolarized Si magnetic resonance imaging

    DEFF Research Database (Denmark)

    Atkins, T.M.; Ganguly, S.; Kauzlarich, S.M.

    2013-01-01

    silicide (Na Si) and silicon tetrachloride (SiCl) and were surface functionalized with a variety of passivating ligands. The synthesis scheme results in particles of diameter ~10 nm with long size-adjusted Si spin-lattice relaxation (T) times (>600 s), which are retained after hyperpolarization by low...

  8. In vivo single-shot (13)C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding

    DEFF Research Database (Denmark)

    Schmidt, Rita; Laustsen, Christoffer; Dumez, Jean-Nicolas

    2014-01-01

    are necessary. Several approaches have been customized for hyperpolarized (13)C MRI, including CSI with a center-out k-space encoding, EPSI, and spectrally selective pulses in combination with spiral EPI acquisitions. Recent studies have described the potential of single-shot alternatives based...... temporal) data sets were obtained at 7T from a murine lymphoma tumor model....

  9. Apparent rate constant mapping using hyperpolarized [1-(13) C]pyruvate

    DEFF Research Database (Denmark)

    Khegai, O.; Schulte, R. F.; Janich, M. A.

    2014-01-01

    Hyperpolarization of [1-13C]pyruvate in solution allows real-time measurement of uptake and metabolism using MR spectroscopic methods. After injection and perfusion, pyruvate is taken up by the cells and enzymatically metabolized into downstream metabolites such as lactate, alanine, and bicarbona...

  10. Hyperpolarized 1-13C Pyruvate Imaging of Porcine Cardiac Metabolism shift by GIK Intervention

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Tougaard, Rasmus Stilling; Mikkelsen, Emmeli

    to evaluate the general feasibility to detect an imposed shift in metabolic substrate utilization during metabolic modulation with glucose, insulin and potassium (GIK) infusion. This study demonstrates that hyperpolarized 13C-pyruvate, in a large animal, is a feasible method for cardiac studies, and...

  11. Efficient purification and concentration of viruses from a large body of high turbidity seawater.

    Science.gov (United States)

    Sun, Guowei; Xiao, Jinzhou; Wang, Hongming; Gong, Chaowen; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2014-01-01

    Marine viruses are the most abundant entities in the ocean and play crucial roles in the marine ecological system. However, understanding of viral diversity on large scale depends on efficient and reliable viral purification and concentration techniques. Here, we report on developing an efficient method to purify and concentrate viruses from large body of high turbidity seawater. The developed method characterizes with high viral recovery efficiency, high concentration factor, high viral particle densities and high-throughput, and is reliable for viral concentration from high turbidity seawater. Recovered viral particles were used directly for subsequent analysis by epifluorescence microscopy, transmission electron microscopy and metagenomic sequencing. Three points are essential for this method:•The sampled seawater (>150 L) was initially divided into two parts, water fraction and settled matter fraction, after natural sedimentation.•Both viruses in the water fraction concentrated by tangential flow filtration (TFF) and viruses isolated from the settled matter fraction were considered as the whole viral community in high turbidity seawater.•The viral concentrates were re-concentrated by using centrifugal filter device in order to obtain high density of viral particles.

  12. NMR study of hyper-polarized {sup 129}Xe and applications to liquid-phase NMR experiments; Etude de la resonance magnetique nucleaire du Xenon{sup 129} hyperpolarise et applications en RMN des liquides

    Energy Technology Data Exchange (ETDEWEB)

    Marion, D

    2008-07-15

    In liquid samples where both nuclear polarization and spin density are strong, the magnetization dynamics, which can be analysed by NMR (nuclear magnetic resonance) methods, is deeply influenced by the internal couplings induced by local dipolar fields. The present thesis describes some of the many consequences associated to the presence in the sample of concentrated xenon hyper-polarized by an optical pumping process. First, we deal with the induced modifications in frequency and line width of the proton and xenon spectra, then we present the results of SPIDER, a coherent polarization transfer experiment designed to enhance the polarization of protons, in order to increase their NMR signal level. A third part is dedicated to the description of the apparition of repeated chaotic maser emissions by un unstable xenon magnetization coupled to the detection coil tuned at the xenon Larmor frequency (here 138 MHz). In the last part, we present a new method allowing a better tuning of any NMR detection probe and resulting in sensible gains in terms of sensitivity and signal shaping. Finally, we conclude with a partial questioning of the classical relaxation theory in the specific field of highly polarized and concentrated spin systems in a liquid phase. (author)

  13. CYP epoxygenase-derived H2O2 is involved in the endothelium-derived hyperpolarization (EDH) and relaxation of intrarenal arteries.

    Science.gov (United States)

    Muñoz, Mercedes; López-Oliva, Maria Elvira; Pinilla, Estéfano; Martínez, María Pilar; Sánchez, Ana; Rodríguez, Claudia; García-Sacristán, Albino; Hernández, Medardo; Rivera, Luis; Prieto, Dolores

    2017-05-01

    Reactive oxygen species (ROS) like hydrogen peroxide (H 2 O 2 ) are involved in the in endothelium-derived hyperpolarization (EDH)-type relaxant responses of coronary and mesenteric arterioles. The role of ROS in kidney vascular function has mainly been investigated in the context of harmful ROS generation associated to kidney disease. The present study was sought to investigate whether H 2 O 2 is involved in the endothelium-dependent relaxations of intrarenal arteries as well the possible endothelial sources of ROS generation involved in these responses. Under conditions of cyclooxygenase (COX) and nitric oxide (NO) synthase inhibition, acetylcholine (ACh) induced relaxations and stimulated H 2 O 2 release that were reduced by catalase and by the glutathione peroxidase (GPx) mimetic ebselen in rat renal interlobar arteries, suggesting the involvement of H 2 O 2 in the endothelium-dependent responses. ACh relaxations were also blunted by the CYP2C inhibitor sulfaphenazole and by the NADPH oxidase inhibitor apocynin. Acetylcholine stimulated both superoxide (O 2 •- ) and H 2 O 2 production that were reduced by sulfaphenazole and apocynin. Expression of the antioxidant enzyme CuZnSOD and of the H 2 O 2 reducing enzymes catalase and GPx-1 was found in both intrarenal arteries and renal cortex. On the other hand, exogenous H 2 O 2 relaxed renal arteries by decreasing vascular smooth muscle (VSM) intracellular calcium concentration [Ca 2+ ] i and markedly enhanced endothelial K Ca currents in freshly isolated renal endothelial cells. CYP2C11 and CYP2C23 epoxygenases were highly expressed in interlobar renal arteries and renal cortex, respectively, and were co-localized with eNOS in renal endothelial cells. These results demonstrate that H 2 O 2 is involved in the EDH-type relaxant responses of renal arteries and that CYP 2C epoxygenases are physiologically relevant endothelial sources of vasodilator H 2 O 2 in the kidney. Copyright © 2017 Elsevier Inc. All rights

  14. High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Chris G.; Laycak, Danny T.; Hoppes, William; Tran,Nguyen T.; Shi, Frank G.

    2004-05-26

    Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrations greater than 4 g/L. The FIT and turbidity measurements were sensitive to sediment particle size. Particle size dependence of transmittance and turbidity measurement poses the greatest problem for calibration to suspended sediment concentration. While the FIT was demonstrated to provide acceptable measurements of high suspended sediment concentrations, approaches to real-time suspended sediment detection need to address the particle size dependence in concentration measurements.

  15. Rheology of dilute acid hydrolyzed corn stover at high solids concentration.

    Science.gov (United States)

    Ehrhardt, M R; Monz, T O; Root, T W; Connelly, R K; Scott, C T; Klingenberg, D J

    2010-02-01

    The rheological properties of acid hydrolyzed corn stover at high solids concentration (20-35 wt.%) were investigated using torque rheometry. These materials are yield stress fluids whose rheological properties can be well represented by the Bingham model. Yield stresses increase with increasing solids concentration and decrease with increasing hydrolysis reaction temperature, acid concentration, and rheometer temperature. Plastic viscosities increase with increasing solids concentration and tend to decrease with increasing reaction temperature and acid concentration. The solids concentration dependence of the yield stress is consistent with that reported for other fibrous systems. The changes in yield stress with reaction conditions are consistent with observed changes in particle size. This study illustrates that torque rheometry can be used effectively to measure rheological properties of concentrated biomass.

  16. Novel DDR Processing of Corn Stover Achieves High Monomeric Sugar Concentrations from Enzymatic Hydrolysis (230 g/L) and High Ethanol Concentration (10% v/v) During Fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaowen; Jennings, Ed; Shekiro, Joe; Kuhn, Erik M.; O' Brien, Marykate; Wang, Wei; Schell, Daniel J.; Himmel, Mike; Elander, Richard T.; Tucker, Melvin P.

    2015-04-03

    Distilling and purifying ethanol, butanol, and other products from second and later generation lignocellulosic biorefineries adds significant capital and operating cost for biofuels production. The energy costs associated with distillation affects plant gate and life cycle analysis costs. Lower titers in fermentation due to lower sugar concentrations from pretreatment increase both energy and production costs. In addition, higher titers decrease the volumes required for enzymatic hydrolysis and fermentation vessels. Therefore, increasing biofuels titers has been a research focus in renewable biofuels production for several decades. In this work, we achieved over 200 g/L of monomeric sugars after high solids enzymatic hydrolysis using the novel deacetylation and disc refining (DDR) process on corn stover. The high sugar concentrations and low chemical inhibitor concentrations from the DDR process allowed ethanol titers as high as 82 g/L in 22 hours, which translates into approximately 10 vol% ethanol. To our knowledge, this is the first time that 10 vol% ethanol in fermentation derived from corn stover without any sugar concentration or purification steps has been reported. Techno-economic analysis shows the higher titer ethanol achieved from the DDR process could significantly reduce the minimum ethanol selling price from cellulosic biomass.

  17. Investigating high-concentration monoclonal antibody powder suspension in nonaqueous suspension vehicles for subcutaneous injection.

    Science.gov (United States)

    Bowen, Mayumi; Armstrong, Nick; Maa, Yuh-Fun

    2012-12-01

    Developing high-concentration monoclonal antibody (mAb) liquid formulations for subcutaneous (s.c.) administration is challenging because increased viscosity makes injection difficult. To overcome this obstacle, we investigated a nonaqueous powder suspension approach. Three IgG1 mAbs were spray dried and suspended at different concentrations in Miglyol® 840, benzyl benzoate, or ethyl lactate. Suspensions were characterized for viscosity, particle size, and syringeability; physical stability was visually inspected. Suspensions generally outperformed liquid solutions for injectability despite higher viscosity at the same mAb concentrations. Powder formulations and properties had little effect on viscosity or injectability. Ethyl lactate suspensions had lowest viscosity (Miglyol® 840 improved overall performance in high mAb concentration suspensions. This study demonstrated the viability of high mAb concentration (>300 mg/mL) in suspension formulations for s.c. administration. Copyright © 2012 Wiley Periodicals, Inc.

  18. High-concentration mirror-based Kohler integrating system for tandem solar cells

    Science.gov (United States)

    Winston, R.; Benitez, P.; Cvetkovic, A.

    2006-06-01

    A novel two-mirror high concentration nonimaging optic has been designed that shares the advantages of present two mirror aplanatic imaging concentrators but also overcomes their main limitation of trade-off between acceptance angle and irradiance uniformity. A system concept has been defined, and a first prototype in under development.

  19. Development of automatic high-concentration boron measurement technique; Konodo hoso jido sokutei gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, T.; Honda, S.; Ito, A. [Kyushu Electric Power Co. Inc., Fukuoka (Japan)

    1997-03-01

    The technology that can automatically measure the boron concentration in boric acid water was developed. A high-concentration boric acid solution must be held at a high temperature to prevent the deposition. Skill and precision ({plus_minus}0.2 to 0.3% for 10 to 2500 ppm as boron concentration, and {plus_minus}2 to 3% for 2500 to 25,000 ppm) are required to analyze the boric acid solution manually. In theory, the boron concentration in a wide range can be measured, and boron has a constant-temperature function. A density hydrometer method that facilitates the treatment and calibration in high precision and at low cost was chosen. The vibration period generated when vibration is given to the solution specimen put in a U-tube is higher as the density is lower. On the basis of this theory, the density of a specimen can be obtained according to the relation with the same data of the known-concentration boric acid water. The high-concentration boric acid water that cannot be measured by the existing boron densitometer can be measured directly. It can also be measured in a low-concentration area. The technique can be used in a laboratory as the simplified method that is replaced by the current manual analysis. The reduction effect of analytical chemical`s waste liquid can also be expected. In the electric power industry, automated equipment is required for high efficiency and labor saving. 13 figs., 3 tabs.

  20. Using fractional extraction method to separate Mo from U in high concentration solution

    International Nuclear Information System (INIS)

    Zhao Pinzhi; Cheng Guangrong; Ma Xiuhua

    1996-01-01

    The author presents investigation on separating Mo from U in acid high concentration lixivium with fractional extraction of secondary amine (7203) and D2EHPA and preparing qualified products of ammonium molybdate and sodium diuranate

  1. Application of Hydrothermal Treatment to High Concentrated Sewage Sludge for Anaerobic Digestion Process

    OpenAIRE

    M. Orikawa; H. Kamahara; Y. Atsuta; H. Daimon

    2013-01-01

    Tomato and seaweed were produced by utilizing CO2 and heat discharged from power generation using biogas in Toyogawa biomass park, Japan. The biogas was obtained by anaerobic digestion with hydrothermal treatment. The hydrothermal treatment was applied to the high concentrated sewage sludge (22 % total solids (TS) dewatered sludge). The purpose of this study is to clarify the effect of hydrothermal treatment on the qualities of high concentrated sewage sludge, by analyzing particulate organic...

  2. High surface hole concentration p-type GaN using Mg implantation

    International Nuclear Information System (INIS)

    Long Tao; Yang Zhijian; Zhang Guoyi

    2001-01-01

    Mg ions were implanted on Mg-doped GaN grown by metalorganic chemical vapor deposition (MOCVD). The p-type GaN was achieved with high hole concentration (8.28 x 10 17 cm -3 ) conformed by Van derpauw Hall measurement after annealing at 800 degree C for 1 h. this is the first experimental report of Mg implantation on Mg-doped GaN and achieving p-type GaN with high surface hole concentration

  3. Compact high-flux two-stage solar collectors based on tailored edge-ray concentrators

    Science.gov (United States)

    Friedman, Robert P.; Gordon, Jeffrey M.; Ries, Harald

    1995-08-01

    Using the recently-invented tailored edge-ray concentrator (TERC) approach for the design of compact two-stage high-flux solar collectors--a focusing primary reflector and a nonimaging TERC secondary reflector--we present: 1) a new primary reflector shape based on the TERC approach and a secondary TERC tailored to its particular flux map, such that more compact concentrators emerge at flux concentration levels in excess of 90% of the thermodynamic limit; and 2) calculations and raytrace simulations result which demonstrate the V-cone approximations to a wide variety of TERCs attain the concentration of the TERC to within a few percent, and hence represent practical secondary concentrators that may be superior to corresponding compound parabolic concentrator or trumpet secondaries.

  4. Gravitational settling of a highly concentrated system of solid spherical particles

    Science.gov (United States)

    Arkhipov, V. A.; Usanina, A. S.

    2017-09-01

    In the present paper, we report on the results of an experimental study of the process of gravity sedimentation of a cloud of monodispersed solid spherical particles with initial volume concentration C > 0.03, which was performed in a wide range of Reynolds numbers. An analytical estimate of the settling regimes of spherical particle clouds is presented. A new method for creating a spherical particle cloud with a high concentration of particles is proposed. A qualitative picture of the settling process of a highly concentrated particle cloud under gravity is revealed. A criterial dependence for the drag coefficient of a sedimenting spherical particle cloud as an entity is obtained.

  5. High serum uric acid concentration predicts poor survival in patients with breast cancer.

    Science.gov (United States)

    Yue, Cai-Feng; Feng, Pin-Ning; Yao, Zhen-Rong; Yu, Xue-Gao; Lin, Wen-Bin; Qian, Yuan-Min; Guo, Yun-Miao; Li, Lai-Sheng; Liu, Min

    2017-10-01

    Uric acid is a product of purine metabolism. Recently, uric acid has gained much attraction in cancer. In this study, we aim to investigate the clinicopathological and prognostic significance of serum uric acid concentration in breast cancer patients. A total of 443 female patients with histopathologically diagnosed breast cancer were included. After a mean follow-up time of 56months, survival was analysed using the Kaplan-Meier method. To further evaluate the prognostic significance of uric acid concentrations, univariate and multivariate Cox regression analyses were applied. Of the clinicopathological parameters, uric acid concentration was associated with age, body mass index, ER status and PR status. Univariate analysis identified that patients with increased uric acid concentration had a significantly inferior overall survival (HR 2.13, 95% CI 1.15-3.94, p=0.016). In multivariate analysis, we found that high uric acid concentration is an independent prognostic factor predicting death, but insufficient to predict local relapse or distant metastasis. Kaplan-Meier analysis indicated that high uric acid concentration is related to the poor overall survival (p=0.013). High uric acid concentration predicts poor survival in patients with breast cancer, and might serve as a potential marker for appropriate management of breast cancer patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Evaluation of heterogeneous metabolic profile in an orthotopic human glioblastoma xenograft model using compressed sensing hyperpolarized 3D 13C magnetic resonance spectroscopic imaging.

    Science.gov (United States)

    Park, Ilwoo; Hu, Simon; Bok, Robert; Ozawa, Tomoko; Ito, Motokazu; Mukherjee, Joydeep; Phillips, Joanna J; James, C David; Pieper, Russell O; Ronen, Sabrina M; Vigneron, Daniel B; Nelson, Sarah J

    2013-07-01

    High resolution compressed sensing hyperpolarized (13)C magnetic resonance spectroscopic imaging was applied in orthotopic human glioblastoma xenografts for quantitative assessment of spatial variations in (13)C metabolic profiles and comparison with histopathology. A new compressed sensing sampling design with a factor of 3.72 acceleration was implemented to enable a factor of 4 increase in spatial resolution. Compressed sensing 3D (13)C magnetic resonance spectroscopic imaging data were acquired from a phantom and 10 tumor-bearing rats following injection of hyperpolarized [1-(13)C]-pyruvate using a 3T scanner. The (13)C metabolic profiles were compared with hematoxylin and eosin staining and carbonic anhydrase 9 staining. The high-resolution compressed sensing (13)C magnetic resonance spectroscopic imaging data enabled the differentiation of distinct (13)C metabolite patterns within abnormal tissues with high specificity in similar scan times compared to the fully sampled method. The results from pathology confirmed the different characteristics of (13)C metabolic profiles between viable, non-necrotic, nonhypoxic tumor, and necrotic, hypoxic tissue. Copyright © 2012 Wiley Periodicals, Inc.

  7. Study on high concentration solar concentrator using a Fresnel lens with a secondary concentrator; Fresnel lens to niji shukokei wo mochiita solar chemistry yo kobairitsu shukokei ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, T; Suzuki, A; Fujibayashi, K [Tokyo University of Agriculture and Technology, Tokyo (Japan)

    1997-11-25

    A high concentration light collection system for solar chemistry was devised by using an inexpensive Fresnel lens in a primary concentration system and a conical type concentrator in a secondary concentration system. A Fresnel lens alone would not achieve sufficiently high light collecting magnification to attain high temperatures because of restrictions in the opening angle as seen from a focus. Therefore, a secondary concentration system was installed on a focus for an attempt of stopping. Reflection plane of a three-dimensional compound parabolic concentrator (CPC) is a rotary parabolic plane, whose process is expensive because of its surface processing accuracy. Therefore, a conical type concentrator was employed as a secondary concentration system. This system may not be capable of achieving as high concentration as in the CPC, but its shape is simple and it is inexpensive. In its optimization, a complete black body surface placed in vacuum atmosphere was hypothesized as a light concentrating part for the secondary concentration system to calculate heat collecting efficiencies at respective temperature settings. Using simultaneously the secondary concentration system, rather than collecting heat by using a Fresnel lens alone, has attained as high value as from 5.99% (500 degC) to 43.47% (1400 degC). Economical high-temperature heat collection of solar chemistry level may be possible by using a Fresnel lens and a conical secondary concentration system. 1 ref., 7 figs., 2 tabs.

  8. Investigating tumor perfusion and metabolism using multiple hyperpolarized 13C compounds: HP001, pyruvate and urea

    DEFF Research Database (Denmark)

    von Morze, Cornelius; Larson, Peder E.Z.; Hu, Simon

    2012-01-01

    The metabolically inactive hyperpolarized agents HP001 (bis-1,1-(hydroxymethyl)-[1-13C]cyclopropane-d8) and urea enable a new type of perfusion magnetic resonance imaging based on a direct signal source that is background-free. The addition of perfusion information to metabolic information obtained...... (T1=95 s ex vivo, 32 s in vivo at 3 T) using a pulse sequence with balanced steady-state free precession and ramped flip angle over time for efficient utilization of the hyperpolarized magnetization and three-dimensional echo-planar spectroscopic imaging of urea copolarized with [1-13C...... of separate dynamic HP001 imaging and copolarized pyruvate/urea imaging were compared. A strong and significant correlation (R=0.73, P=.02) detected between the urea and HP001 data confirmed the value of copolarizing urea with pyruvate for simultaneous assessment of perfusion and metabolism....

  9. Dysfunctional Hyperpolarization-Activated Cyclic Nucleotide-gated Ion Channels in Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    Xiaoqi Zhao

    Full Text Available Abstract Hyperpolarization-activated cyclic nucleotide-gated (HCN channels are reverse voltage-dependent, and their activation depends on the hyperpolarization of the membrane and may be directly or indirectly regulated by the cyclic adenosine monophosphate (cAMP or other signal-transduction cascades. The distribution, quantity and activation states of HCN channels differ in tissues throughout the body. Evidence exhibits that HCN channels play critical roles in the generation and conduction of the electrical impulse and the physiopathological process of some cardiac diseases. They may constitute promising drug targets in the treatment of these cardiac diseases. Pharmacological treatment targeting HCN channels is of benefit to these cardiac conditions.

  10. Methods to assess high-resolution subsurface gas concentrations and gas fluxes in wetland ecosystems

    DEFF Research Database (Denmark)

    Elberling, Bo; Kühl, Michael; Glud, Ronnie Nøhr

    2013-01-01

    The need for measurements of soil gas concentrations and surface fluxes of greenhouse gases at high temporal and spatial resolution in wetland ecosystem has lead to the introduction of several new analytical techniques and methods. In addition to the automated flux chamber methodology for high-re...

  11. Prodigious Effects of Concentration Intensification on Nanoparticle Synthesis: A High-Quality, Scalable Approach

    KAUST Repository

    Williamson, Curtis B.

    2015-12-23

    © 2015 American Chemical Society. Realizing the promise of nanoparticle-based technologies demands more efficient, robust synthesis methods (i.e., process intensification) that consistently produce large quantities of high-quality nanoparticles (NPs). We explored NP synthesis via the heat-up method in a regime of previously unexplored high concentrations near the solubility limit of the precursors. We discovered that in this highly concentrated and viscous regime the NP synthesis parameters are less sensitive to experimental variability and thereby provide a robust, scalable, and size-focusing NP synthesis. Specifically, we synthesize high-quality metal sulfide NPs (<7% relative standard deviation for Cu2-xS and CdS), and demonstrate a 10-1000-fold increase in Cu2-xS NP production (>200 g) relative to the current field of large-scale (0.1-5 g yields) and laboratory-scale (<0.1 g) efforts. Compared to conventional synthesis methods (hot injection with dilute precursor concentration) characterized by rapid growth and low yield, our highly concentrated NP system supplies remarkably controlled growth rates and a 10-fold increase in NP volumetric production capacity (86 g/L). The controlled growth, high yield, and robust nature of highly concentrated solutions can facilitate large-scale nanomanufacturing of NPs by relaxing the synthesis requirements to achieve monodisperse products. Mechanistically, our investigation of the thermal and rheological properties and growth rates reveals that this high concentration regime has reduced mass diffusion (a 5-fold increase in solution viscosity), is stable to thermal perturbations (64% increase in heat capacity), and is resistant to Ostwald ripening.

  12. Imaging cerebral 2-ketoisocaproate metabolism with hyperpolarized (13)C Magnetic Resonance Spectroscopic Imaging

    DEFF Research Database (Denmark)

    Butt, Sadia Asghar; Søgaard, Lise Vejby-Christensen; Magnusson, Peter O.

    2012-01-01

    The branched chain amino acid transaminase (BCAT) has an important role in nitrogen shuttling and glutamate metabolism in the brain. The purpose of this study was to describe the cerebral distribution and metabolism of hyperpolarized 2-keto[1-(13)C]isocaproate (KIC) in the normal rat using magnet...... & Metabolism advance online publication, 28 March 2012; doi:10.1038/jcbfm.2012.34....

  13. High nitrate concentrations in some Midwest United States streams in 2013 after the 2012 drought

    Science.gov (United States)

    Van Metre, Peter C.; Frey, Jeffrey W.; Musgrove, MaryLynn; Nakagaki, Naomi; Qi, Sharon L.; Mahler, Barbara J.; Wieczorek, Michael; Button, Daniel T.

    2016-01-01

    Nitrogen sources in the Mississippi River basin have been linked to degradation of stream ecology and to Gulf of Mexico hypoxia. In 2013, the USGS and the USEPA characterized water quality stressors and ecological conditions in 100 wadeable streams across the midwestern United States. Wet conditions in 2013 followed a severe drought in 2012, a weather pattern associated with elevated nitrogen concentrations and loads in streams. Nitrate concentrations during the May to August 2013 sampling period ranged from nitrate concentrations at the 100 sites were compared with May to June concentrations predicted from a regression model developed using historical nitrate data. Observed concentrations for 17 sites, centered on Iowa and southern Minnesota, were outside the 95% confidence interval of the regression-predicted mean, indicating that they were anomalously high. The sites with a nitrate anomaly had significantly higher May to June nitrate concentrations than sites without an anomaly (means, 19.8 and 3.6 mg L−1, respectively) and had higher antecedent precipitation indices, a measure of the departure from normal precipitation, in 2012 and 2013. Correlations between nitrate concentrations and watershed characteristics and nitrogen and oxygen isotopes of nitrate indicated that fertilizer and manure used in crop production, principally corn, were the dominant sources of nitrate. The anomalously high nitrate levels in parts of the Midwest in 2013 coincide with reported higher-than-normal nitrate loads in the Mississippi River.

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

    Science.gov (United States)

    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@Ag 2 S@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 selective electrocatalyst–based direct methanol fuel cell operated at high concentrations of methanol

    Science.gov (United States)

    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

  16. High frequency measurement of nitrate concentration in the Lower Mississippi River, USA

    Science.gov (United States)

    Duan, Shuiwang; Powell, Rodney T.; Bianchi, Thomas S.

    2014-11-01

    Nutrient concentrations in the Mississippi River have increased dramatically since the 1950s, and high frequency measurements on nitrate concentration are required for accurate load estimations and examinations on nitrate transport and transformation processes. This three year record of high temporal resolution (every 2-3 h) data clearly illustrates the importance of high frequency sampling in improving load estimates and resolving variations in nitrate concentration with river flow and tributary inputs. Our results showed large short-term (days to weeks) variations in nitrate concentration but with no diurnal patterns. A repeatable and pronounced seasonal pattern of nitrate concentration was observed, and showed gradual increases from the lowest values in September (during base-flow), to the highest in June - which was followed by a rapid decrease. This seasonal pattern was only moderately linked with water discharge, and more controlled by nitrogen transformation/export from watershed as well as mixing patterns of the two primary tributaries (the upper Mississippi and the Ohio Rivers), which have distinctly different nitrate concentrations and flow patterns. Based on continuous in situ flow measurements, we estimated 554-886 × 106 kg of nitrate-N was exported from the Mississippi River system during years 2004-2006, which was <9% and <16% lower than U.S. Geological Survey's (USGS) estimates using their LOADEST or composite methods, respectively. USGS methods generally overestimated nitrate loads during rising stages and underestimated the loads during falling stages. While changes in nitrate concentrations in large rivers are generally not as responsive to alterations in diurnal inputs and/or watershed hydrology as small rivers, high-frequency water quality sampling would help in monitoring short-term (days to weeks) variations in nutrient concentration patterns and thus improve the accuracy of nutrient flux estimates.

  17. Real-time tracking of dissociation of hyperpolarized 89Y-DTPA: a model for degradation of open-chain Gd3+ MRI contrast agents

    Science.gov (United States)

    Ferguson, Sarah; Niedbalski, Peter; Parish, Christopher; Kiswandhi, Andhika; Kovacs, Zoltan; Lumata, Lloyd

    Gadolinium (Gd) complexes are widely used relaxation-based clinical contrast agents in magnetic resonance imaging (MRI). Gd-based MRI contrast agents with open-chain ligand such as Gd-DTPA, commercially known as magnevist, are less stable compared to Gd complexes with macrocyclic ligands such as GdDOTA (Dotarem). The dissociation of Gd-DPTA into Gd ion and DTPA ligand under certain biological conditions such as high zinc levels can potentially cause kidney damage. Since Gd is paramagnetic, direct NMR detection of the Gd-DTPA dissociation is quite challenging due to ultra-short relaxation times. In this work, we have investigated Y-DTPA as a model for Gd-DPTA dissociation under high zinc content solutions. Using dissolution dynamic nuclear polarization (DNP), the 89Y NMR signal is amplified by several thousand-fold. Due to the the relatively long T1 relaxation time of 89Y which translates to hyperpolarization lifetime of several minutes, the dissociation of Y-DTPA can be tracked in real-time by hyperpolarized 89Y NMR spectroscopy. Dissociation kinetic rates and implications on the degradation of open-chain Gd3+ MRI contrast agents will be discussed. This work was supported by the U.S. Department of Defense Award Number W81XWH-14-1-0048 and by the Robert A. Welch Foundation research Grant Number AT-1877.

  18. Clearly Transparent Nanopaper from Highly Concentrated Cellulose Nanofiber Dispersion Using Dilution and Sonication

    Directory of Open Access Journals (Sweden)

    Takaaki Kasuga

    2018-02-01

    Full Text Available Nanopaper prepared from holocellulose pulp is one of the best substrates for flexible electronics because of its high thermal resistance and high clear transparency. However, the clearness of nanopaper decreases with increasing concentration of the starting cellulose nanofiber dispersion—with the use of a 2.2 wt % dispersion, for example—resulting in translucent nanopaper with a high haze of 44%. To overcome this problem, we show that the dilution of this high-concentration dispersion with water followed by sonication for 10 s reduces the haze to less than 10% while maintaining the high thermal resistance of the nanopaper. Furthermore, the combination of water dilution and a short sonication treatment improves the clearness of the nanopaper, which would translate into cost savings for the transportation and storage of this highly concentrated cellulose nanofiber dispersion. Finally, we demonstrate the improvement of the electrical conductivity of clear transparent nanopaper prepared from an initially high-concentration dispersion by dropping and heating silver nanowire ink on the nanopaper. These achievements will pave the way toward the realization of the mass production of nanofiber-based flexible devices.

  19. High Voltage Solar Concentrator Experiment with Implications for Future Space Missions

    Science.gov (United States)

    Mehdi, Ishaque S.; George, Patrick J.; O'Neill, Mark; Matson, Robert; Brockschmidt, Arthur

    2004-01-01

    This paper describes the design, development, fabrication, and test of a high performance, high voltage solar concentrator array. This assembly is believed to be the first ever terrestrial triple-junction-cell solar array rated at over 1 kW. The concentrator provides over 200 W/square meter power output at a nominal 600 Vdc while operating under terrestrial sunlight. Space-quality materials and fabrication techniques were used for the array, and the 3005 meter elevation installation below the Tropic of Cancer allowed testing as close as possible to space deployment without an actual launch. The array includes two concentrator modules, each with a 3 square meter aperture area. Each concentrator module uses a linear Fresnel lens to focus sunlight onto a photovoltaic receiver that uses 240 series-connected triple-junction solar cells. Operation of the two receivers in series can provide 1200 Vdc which would be adequate for the 'direct drive' of some ion engines or microwave transmitters in space. Lens aperture width is 84 cm and the cell active width is 3.2 cm, corresponding to a geometric concentration ratio of 26X. The evaluation includes the concentrator modules, the solar cells, and the materials and techniques used to attach the solar cells to the receiver heat sink. For terrestrial applications, a finned aluminum extrusion was used for the heat sink for the solar cells, maintaining a low cell temperature so that solar cell efficiency remains high.

  20. The role of hyperpolarized {sup 129}xenon in MR imaging of pulmonary function

    Energy Technology Data Exchange (ETDEWEB)

    Ebner, Lukas [Cardiothoracic Imaging, Duke University Medical Center, Department of Radiology, Duke University, Durham, NC (United States); Kammerman, Jeff [Department of Medical Physics, University of Wisconsin, Madison, WI (United States); Driehuys, Bastiaan [Center for In Vivo Microscopy, Duke University, Durham, NC (United States); Schiebler, Mark L. [Department of Radiology, University of Wisconsin, Madison, WI (United States); Cadman, Robert V. [Department of Medical Physics, University of Wisconsin, Madison, WI (United States); Fain, Sean B., E-mail: sfain@wisc.edu [Departments of Medical Physics, Radiology, and Biomedical Engineering, University of Wisconsin, Madison, WI (United States)

    2017-01-15

    Highlights: • Recent advances in hyperpolarized 129Xe MRI are reviewed. • Xenon MRI allows for functional imaging of ventilation, diffusion, and gas exchange. • Xenon’s unique gas exchange imaging capabilities are highlighted. • Applications to obstructive and restrictive lung diseases are presented. • These advances are ready for translation to clinical applications. - Abstract: In the last two decades, functional imaging of the lungs using hyperpolarized noble gases has entered the clinical stage. Both helium ({sup 3}He) and xenon ({sup 129}Xe) gas have been thoroughly investigated for their ability to assess both the global and regional patterns of lung ventilation. With advances in polarizer technology and the current transition towards the widely available {sup 129}Xe gas, this method is ready for translation to the clinic. Currently, hyperpolarized (HP) noble gas lung MRI is limited to selected academic institutions; yet, the promising results from initial clinical trials have drawn the attention of the pulmonary medicine community. HP {sup 129}Xe MRI provides not only 3-dimensional ventilation imaging, but also unique capabilities for probing regional lung physiology. In this review article, we aim to (1) provide a brief overview of current ventilation MR imaging techniques, (2) emphasize the role of HP {sup 129}Xe MRI within the array of different imaging strategies, (3) discuss the unique imaging possibilities with HP {sup 129}Xe MRI, and (4) propose clinical applications.

  1. A catalyzing phantom for reproducible dynamic conversion of hyperpolarized [1-¹³C]-pyruvate.

    Science.gov (United States)

    Walker, Christopher M; Lee, Jaehyuk; Ramirez, Marc S; Schellingerhout, Dawid; Millward, Steven; Bankson, James A

    2013-01-01

    In vivo real time spectroscopic imaging of hyperpolarized ¹³C labeled metabolites shows substantial promise for the assessment of physiological processes that were previously inaccessible. However, reliable and reproducible methods of measurement are necessary to maximize the effectiveness of imaging biomarkers that may one day guide personalized care for diseases such as cancer. Animal models of human disease serve as poor reference standards due to the complexity, heterogeneity, and transient nature of advancing disease. In this study, we describe the reproducible conversion of hyperpolarized [1-¹³C]-pyruvate to [1-¹³C]-lactate using a novel synthetic enzyme phantom system. The rate of reaction can be controlled and tuned to mimic normal or pathologic conditions of varying degree. Variations observed in the use of this phantom compare favorably against within-group variations observed in recent animal studies. This novel phantom system provides crucial capabilities as a reference standard for the optimization, comparison, and certification of quantitative imaging strategies for hyperpolarized tracers.

  2. A catalyzing phantom for reproducible dynamic conversion of hyperpolarized [1-¹³C]-pyruvate.

    Directory of Open Access Journals (Sweden)

    Christopher M Walker

    Full Text Available In vivo real time spectroscopic imaging of hyperpolarized ¹³C labeled metabolites shows substantial promise for the assessment of physiological processes that were previously inaccessible. However, reliable and reproducible methods of measurement are necessary to maximize the effectiveness of imaging biomarkers that may one day guide personalized care for diseases such as cancer. Animal models of human disease serve as poor reference standards due to the complexity, heterogeneity, and transient nature of advancing disease. In this study, we describe the reproducible conversion of hyperpolarized [1-¹³C]-pyruvate to [1-¹³C]-lactate using a novel synthetic enzyme phantom system. The rate of reaction can be controlled and tuned to mimic normal or pathologic conditions of varying degree. Variations observed in the use of this phantom compare favorably against within-group variations observed in recent animal studies. This novel phantom system provides crucial capabilities as a reference standard for the optimization, comparison, and certification of quantitative imaging strategies for hyperpolarized tracers.

  3. The role of hyperpolarized 129xenon in MR imaging of pulmonary function

    International Nuclear Information System (INIS)

    Ebner, Lukas; Kammerman, Jeff; Driehuys, Bastiaan; Schiebler, Mark L.; Cadman, Robert V.; Fain, Sean B.

    2017-01-01

    Highlights: • Recent advances in hyperpolarized 129Xe MRI are reviewed. • Xenon MRI allows for functional imaging of ventilation, diffusion, and gas exchange. • Xenon’s unique gas exchange imaging capabilities are highlighted. • Applications to obstructive and restrictive lung diseases are presented. • These advances are ready for translation to clinical applications. - Abstract: In the last two decades, functional imaging of the lungs using hyperpolarized noble gases has entered the clinical stage. Both helium ( 3 He) and xenon ( 129 Xe) gas have been thoroughly investigated for their ability to assess both the global and regional patterns of lung ventilation. With advances in polarizer technology and the current transition towards the widely available 129 Xe gas, this method is ready for translation to the clinic. Currently, hyperpolarized (HP) noble gas lung MRI is limited to selected academic institutions; yet, the promising results from initial clinical trials have drawn the attention of the pulmonary medicine community. HP 129 Xe MRI provides not only 3-dimensional ventilation imaging, but also unique capabilities for probing regional lung physiology. In this review article, we aim to (1) provide a brief overview of current ventilation MR imaging techniques, (2) emphasize the role of HP 129 Xe MRI within the array of different imaging strategies, (3) discuss the unique imaging possibilities with HP 129 Xe MRI, and (4) propose clinical applications.

  4. Acute hypertensive stress imaged by cardiac hyperpolarized [1-C]pyruvate magnetic resonance

    DEFF Research Database (Denmark)

    Tougaard, Rasmus Stilling; Hansen, Esben Søvsø Szocska; Laustsen, Christoffer

    2018-01-01

    PURPOSE: Deranged metabolism is now recognized as a key causal factor in a variety of heart diseases, and is being studied extensively. However, invasive methods may alter metabolism, and conventional imaging techniques measure tracer uptake but not downstream metabolism. These challenges may...... be overcome by hyperpolarized MR, a noninvasive technique currently crossing the threshold into human trials. The aim of this study was to image metabolic changes in the heart in response to endogastric glucose bolus and to acute hypertension. METHODS: Five postprandial pigs were scanned with hyperpolarized.......008) and ejection fraction decreased from 54 ± 2% to 47 ± 6% (P = 0.03) The hemodynamic changes were accompanied by increases in the hyperpolarized [1-13C]pyruvate MR derived ratios of lactate/alanine (from 0.58 ± 0.13 to 0.78 ± 0.06, P = 0.03) and bicarbonate/alanine (from 0.55 ± 0.12 to 0.91 ± 0.14, P = 0...

  5. Structural changes induced by high-pressure processing in micellar casein and milk protein concentrates.

    Science.gov (United States)

    Cadesky, Lee; Walkling-Ribeiro, Markus; Kriner, Kyle T; Karwe, Mukund V; Moraru, Carmen I

    2017-09-01

    Reconstituted micellar casein concentrates and milk protein concentrates of 2.5 and 10% (wt/vol) protein concentration were subjected to high-pressure processing at pressures from 150 to 450 MPa, for 15 min, at ambient temperature. The structural changes induced in milk proteins by high-pressure processing were investigated using a range of physical, physicochemical, and chemical methods, including dynamic light scattering, rheology, mid-infrared spectroscopy, scanning electron microscopy, proteomics, and soluble mineral analyses. The experimental data clearly indicate pressure-induced changes of casein micelles, as well as denaturation of serum proteins. Calcium-binding α S1 - and α S2 -casein levels increased in the soluble phase after all pressure treatments. Pressurization up to 350 MPa also increased levels of soluble calcium and phosphorus, in all samples and concentrations, whereas treatment at 450 MPa reduced the levels of soluble Ca and P. Experimental data suggest dissociation of calcium phosphate and subsequent casein micelle destabilization as a result of pressure treatment. Treatment of 10% micellar casein concentrate and 10% milk protein concentrate samples at 450 MPa resulted in weak, physical gels, which featured aggregates of uniformly distributed, casein substructures of 15 to 20 nm in diameter. Serum proteins were significantly denatured by pressures above 250 MPa. These results provide information on pressure-induced changes in high-concentration protein systems, and may inform the development on new milk protein-based foods with novel textures and potentially high nutritional quality, of particular interest being the soft gel structures formed at high pressure levels. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

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

    Science.gov (United States)

    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.

  7. Photoluminescence of highly compensated GaAs doped with high concentration of Ge

    Science.gov (United States)

    Watanabe, Masaru; Watanabe, Akira; Suezawa, Masashi

    1999-12-01

    We have studied the photoluminescence (PL) properties of Ge-doped GaAs crystals to confirm the validity of a theory developed by Shklovskii and Efros to explain the donor-acceptor pair (DAP) recombination in potential fluctuation. GaAs crystals doped with Ge of various concentrations were grown by a liquid-encapsulated Czochralski method. They were homogenized by annealing at 1200°C for 20 h under the optimum As vapor pressure. Both quasi-continuous and time-resolved PL spectra were measured at 4.2 K. The quasi-continuous PL spectra showed that the peak position shifted to lower energy as the Ge concentration increased, which was consistent with the Shklovskii and Efros's theory. Under very strong excitation in time-resolved measurements, the exciton peak appeared within short periods after excitation and then the peak shifted to that of DAP recombination. This clearly showed that the potential fluctuation disappeared under strong excitation and then recovered as the recombination proceeded.

  8. Storage in high-barrier pouches increases the sulforaphane concentration in broccoli florets.

    Directory of Open Access Journals (Sweden)

    Yoshio Makino

    Full Text Available Sulforaphane is a phytochemical that is usually found in cruciferous vegetables and is known to have a depressive effect on gastric cancer. Preliminary investigations showed that the sulforaphane concentration in broccoli (Brassica oleracea var. italica florets increased under anoxia. Therefore, in the present study, we examined the effect of different atmospheric conditions on the sulforaphane concentration in broccoli and also tested whether there are concurrent effects on the concentration of ethanol, which is an unfavorable byproduct of fermentation. The sulforaphane concentration in broccoli florets was significantly elevated by 1.9- to 2.8-fold after 2 d of storage under hypoxia at ca. 0% O2 and ca. 24% CO2 at 20°C, whereas no such increase was observed following storage under normoxia at ca. 0% O2 without CO2 at 20°C. Furthermore, after 2 d, the sulforaphane concentration under hypoxia was 1.6- to 2.3-fold higher than that under normoxia. These results suggest that storage under hypoxia with high CO2 levels can elevate the sulforaphane concentration in broccoli florets. However, the elevated sulforaphane concentration could not be maintained beyond 2 d. There was no significant difference in the concentration of ethanol between florets that were stored under hypoxia with/without CO2 or normoxia at 2 d. However, the ethanol concentrations inside the pouches significantly increased between 2 d and 7 d. These findings indicate that the quality of broccoli florets can be improved through storage under hypoxia with high CO2 levels at 20°C for 2 d.

  9. Storage in high-barrier pouches increases the sulforaphane concentration in broccoli florets.

    Science.gov (United States)

    Makino, Yoshio; Nishimura, Yuto; Oshita, Seiichi; Mizosoe, Takaharu; Akihiro, Takashi

    2018-01-01

    Sulforaphane is a phytochemical that is usually found in cruciferous vegetables and is known to have a depressive effect on gastric cancer. Preliminary investigations showed that the sulforaphane concentration in broccoli (Brassica oleracea var. italica) florets increased under anoxia. Therefore, in the present study, we examined the effect of different atmospheric conditions on the sulforaphane concentration in broccoli and also tested whether there are concurrent effects on the concentration of ethanol, which is an unfavorable byproduct of fermentation. The sulforaphane concentration in broccoli florets was significantly elevated by 1.9- to 2.8-fold after 2 d of storage under hypoxia at ca. 0% O2 and ca. 24% CO2 at 20°C, whereas no such increase was observed following storage under normoxia at ca. 0% O2 without CO2 at 20°C. Furthermore, after 2 d, the sulforaphane concentration under hypoxia was 1.6- to 2.3-fold higher than that under normoxia. These results suggest that storage under hypoxia with high CO2 levels can elevate the sulforaphane concentration in broccoli florets. However, the elevated sulforaphane concentration could not be maintained beyond 2 d. There was no significant difference in the concentration of ethanol between florets that were stored under hypoxia with/without CO2 or normoxia at 2 d. However, the ethanol concentrations inside the pouches significantly increased between 2 d and 7 d. These findings indicate that the quality of broccoli florets can be improved through storage under hypoxia with high CO2 levels at 20°C for 2 d.

  10. Cation effect on small phosphonium based ionic liquid electrolytes with high concentrations of lithium salt

    Science.gov (United States)

    Chen, Fangfang; Kerr, Robert; Forsyth, Maria

    2018-05-01

    Ionic liquid electrolytes with high alkali salt concentrations have displayed some excellent electrochemical properties, thus opening up the field for further improvements to liquid electrolytes for lithium or sodium batteries. Fundamental computational investigations into these high concentration systems are required in order to gain a better understanding of these systems, yet they remain lacking. Small phosphonium-based ionic liquids with high concentrations of alkali metal ions have recently shown many promising results in experimental studies, thereby prompting us to conduct further theoretical exploration of these materials. Here, we conducted a molecular dynamics simulation on four small phosphonium-based ionic liquids with 50 mol. % LiFSI salt, focusing on the effect of cation structure on local structuring and ion diffusional and rotational dynamics—which are closely related to the electrochemical properties of these materials.

  11. High-dimensional orbital angular momentum entanglement concentration based on Laguerre–Gaussian mode selection

    International Nuclear Information System (INIS)

    Zhang, Wuhong; Su, Ming; Wu, Ziwen; Lu, Meng; Huang, Bingwei; Chen, Lixiang

    2013-01-01

    Twisted photons enable the definition of a Hilbert space beyond two dimensions by orbital angular momentum (OAM) eigenstates. Here we propose a feasible entanglement concentration experiment, to enhance the quality of high-dimensional entanglement shared by twisted photon pairs. Our approach is started from the full characterization of entangled spiral bandwidth, and is then based on the careful selection of the Laguerre–Gaussian (LG) modes with specific radial and azimuthal indices p and ℓ. In particular, we demonstrate the possibility of high-dimensional entanglement concentration residing in the OAM subspace of up to 21 dimensions. By means of LabVIEW simulations with spatial light modulators, we show that the Shannon dimensionality could be employed to quantify the quality of the present concentration. Our scheme holds promise in quantum information applications defined in high-dimensional Hilbert space. (letter)

  12. An assessment of a spiral duct centrifuge using standard and high concentration aerosols

    International Nuclear Information System (INIS)

    Smith, A.D.

    1982-12-01

    The Stoeber spiral duct centrifuge has been calibrated by means of polystyrene latex microspheres for the subsequent measurement of aerosol particle size distributions. Intermediate (1 g m -3 ) ad high (100 g m -3 ) sodium chloride aerosol concentrations have been sampled by the centrifuge to determine possible limitations in the equipment. Corrections have to be made for the effect of Coriolis forces, and aerosol concentrations above 1 g m -3 should be diluted before sampling. The spiral duct centrifuge is an extremely versatile instrument for aerosol analysis, and shows a high degree of reliability when operated under well-defined conditions. (author)

  13. High surface hole concentration p-type GaN using Mg implantation

    CERN Document Server

    Long Tao; Zhang Guo Yi

    2001-01-01

    Mg ions were implanted on Mg-doped GaN grown by metalorganic chemical vapor deposition (MOCVD). The p-type GaN was achieved with high hole concentration (8.28 x 10 sup 1 sup 7 cm sup - sup 3) conformed by Van derpauw Hall measurement after annealing at 800 degree C for 1 h. this is the first experimental report of Mg implantation on Mg-doped GaN and achieving p-type GaN with high surface hole concentration

  14. Vitamin E concentrations in adults with HIV/AIDS on highly active antiretroviral therapy.

    Science.gov (United States)

    Itinoseki Kaio, Daniella J Itinoseki; Rondó, Patricia Helen C; Luzia, Liania Alves; Souza, José Maria P; Firmino, Aline Vale; Santos, Sigrid Sousa

    2014-09-15

    HIV/AIDS patients are probably more predisposed to vitamin E deficiency, considering that they are more exposed to oxidative stress. Additionally, there are an extensive number of drugs in the highly active antiretroviral therapy (HAART) regimens that may interfere with vitamin E concentrations. The objective of this study was to compare serum concentrations of alpha-tocopherol in 182 HIV/AIDS patients receiving different HAART regimens. The patients were divided into three groups according to regimen: nucleoside analog reverse-transcriptase inhibitors (NRTIs) + non-nucleoside analog reverse-transcriptase inhibitors (NNRTIs); NRTIs + protease inhibitors + ritonavir; NRTIs + other classes. Alpha-tocopherol was assessed by high-performance liquid chromatography. Multiple linear regression analysis was used to evaluate the effects of HAART regimen, time of use, and compliance with the regimen on alpha-tocopherol concentrations. Alpha-tocopherol concentrations were on average 4.12 μmol/L lower for the NRTIs + other classes regimen when compared to the NRTIs + NNRTIs regimen (p = 0.037). A positive association (p < 0.001) was observed between alpha-tocopherol and cholesterol concentrations, a finding due, in part, to the relationship between liposoluble vitamins and lipid profile. This study demonstrated differences in alpha-tocopherol concentrations between patients using different HAART regimens, especially regimens involving the use of new drugs. Long-term prospective cohort studies are needed to monitor vitamin E status in HIV/AIDS patients since the beginning of treatment.

  15. Separation and Concentration without Clogging Using a High-Throughput Tunable Filter

    Science.gov (United States)

    Mossige, E. J.; Jensen, A.; Mielnik, M. M.

    2018-05-01

    We present a detailed experimental study of a hydrodynamic filtration microchip and show how chip performance can be tuned and clogging avoided by adjusting the flow rates. We demonstrate concentration and separation of microspheres at throughputs as high as 29 ml /min and with 96% pureness. Results of streakline visualizations show that the thickness of a tunable filtration layer dictates the cutoff size and that two different concentration mechanisms exist. Particles larger than pores are concentrated by low-velocity rolling over the filtration pillars, while particles smaller than pores are concentrated by lateral drift across the filtration layer. Results of microscopic particle image velocimetry and particle-tracking velocimetry show that the degree of lateral migration can be quantified by the slip velocity between the particle and the surrounding fluid. Finally, by utilizing differences in inertia and separation mode, we demonstrate size-based separation of particles in a mixture.

  16. Optical performance evaluation of a solar furnace by measuring the highly concentrated solar flux

    International Nuclear Information System (INIS)

    Lee, Hyunjin; Chai, Kwankyo; Kim, Jongkyu; Lee, Sangnam; Yoon, Hwanki; Yu, Changkyun; Kang, Yongheack

    2014-01-01

    We evaluated optical performance of a solar furnace in the KIER (Korea Institute of Energy Research) by measuring the highly concentrated solar flux with the flux mapping method. We presented and analyzed optical performance in terms of concentrated solar flux distribution and power distribution. We investigated concentration ratio, stagnation temperature, total power, and concentration accuracy with help of a modeling code based on the ray tracing method and thereby compared with other solar furnaces. We also discussed flux changes by shutter opening angles and by position adjustment of reflector facets. In the course of flux analysis, we provided a better understanding of reference flux measurement for calibration, reflectivity measurement with a portable reflectometer, shadowing area consideration for effective irradiation, as well as accuracy and repeatability of flux measurements. The results in the present study will help proper utilization of a solar furnace by facilitating comparison between flux measurements at different conditions and flux estimation during operation

  17. PKU: high plasma phenylalanine concentrations are associated with increased prevalence of mood swings.

    Science.gov (United States)

    Anjema, Karen; van Rijn, Margreet; Verkerk, Paul H; Burgerhof, Johannes G M; Heiner-Fokkema, M Rebecca; van Spronsen, Francjan J

    2011-11-01

    In phenylketonuria, knowledge about the relation between behavior and plasma phenylalanine is scarce. The aim of this study was to determine whether high phenylalanine is associated with disturbed behavior noticed by the patient and or close environment (parents or partners). 48 early treated PKU patients (median age 8.5, range 0-35 years) participated (median phenylalanine concentration in total sample 277 (range 89-1171) μmol/l; and in patients introvert or extravert behavior. The interviewer as well as the respondents were blinded with regard to the phenylalanine concentration. Patients reported less deviant behavior compared to close environment. Mood swings were positively associated with phenylalanine concentrations in the total group (P=0.039) and patients introvert and extravert behavior were not statistically significant. there is a positive association between phenylalanine concentrations and mood swings. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Search after new agents for hyperpolarization-activated and cyclic nucleotide-gated ion channels; Suche nach neuen Wirkstoffen fuer Hyperpolarisationsaktivierte und zyklisch Nukleotid-gesteuerte Ionenkanaele

    Energy Technology Data Exchange (ETDEWEB)

    Struenker, T.

    2005-12-01

    Rhythmic activity of single cells or cellular networks is a common feature of most organisms. Cellular rhythms govern the beating of the heart, cycles of sleep and wakefulness, breathing, and the release of hormones. The endogenous rhythmic activity of many neurons and cardiac relies on a complex interplay between several distinct ion channels. In particular, one type of ion channel plays a prominent role in the control of rhythmic electrical activity because it determines the frequency of the oscillations. The activity of the channels is thus setting the ''pace'' of the activity; therefore, these channels are often referred to as ''pacemaker'' channels. Despite their obvious physiological importance it hasn't been until a few years ago that the genes encoding pacemaker channels have been identified. Because both hyperpolarization and cyclic nucleotides are key elements that control their activity, pacemaker channels have now been designated hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels. From a scientific as well as medical point of view, HCN channels are interesting drug targets. Only a few substances are known that specifically affect HCN channels. In the present study, a microtiter plate-based high throughput screening assay for HCN1 and HCN4 channels was developed. With this assay, known drugs for HCN channels were characterized. Subsequently, venoms of snails, spiders, scorpions, and snakes were screened for toxins affecting HCN channel activity. A few venoms were identified that possibly contain drugs that act on HCN channels. (orig.)

  19. Enhanced Enzymatic Production of Cephalexin at High Substrate Concentration with in situ Product Removal by Complexation

    Directory of Open Access Journals (Sweden)

    Dengchao Li

    2008-01-01

    Full Text Available Cephalexin (CEX was synthesized with 7-amino-3-deacetoxycephalosporanic acid (7-ADCA and D(–-phenylglycine methyl ester (PGME using immobilized penicillin G acylase from Escherichia coli. It was found that substrate concentration and in situ product could remarkably influence the ratio of synthesis to hydrolysis (S/H and the efficiency of CEX synthesis. The optimal ratio of enzyme to substrate was 65 IU/mM 7-ADCA. High substrate concentration improved the 7-ADCA conversion from 61 to 81 % in the process without in situ product removal (ISPR, while in the synthetic process with ISPR, high substrate concentration increased the 7-ADCA conversion from 88 to 98 %. CEX was easily separated from CEX/β-naphthol complex and its purity and overall yield were 99 and 70 %, respectively.

  20. Niacin alters the ruminal microbial composition of cattle under high-concentrate condition

    Directory of Open Access Journals (Sweden)

    Dan Luo

    2017-06-01

    Full Text Available To understand the effects of niacin on the ruminal microbial ecology of cattle under high-concentrate diet condition, Illumina MiSeq sequencing technology was used. Three cattle with rumen cannula were used in a 3 × 3 Latin-square design trial. Three diets were fed to these cattle during 3 periods for 3 days, respectively: high-forage diet (HF; forage-to-concentrate ratio = 80:20, high-concentrate diet (HC; forage-to-concentrate ratio = 20:80, and HC supplemented with 800 mg/kg niacin (HCN. Ruminal pH was measured before feeding and every 2 h after initiating feeding. Ruminal fluid was sampled at the end of each period for microbial DNA extraction. Overall, our findings revealed that subacute ruminal acidosis (SARA was induced and the α-diversity of ruminal bacterial community decreased in the cattle of HC group. Adding niacin in HC could relieve the symptoms of SARA in the cattle but the ruminal pH value and the Shannon index of ruminal bacterial community of HCN group were still lower than those of HF group. Whatever the diet was, the ruminal bacterial community of cattle was dominated by Bacteroidetes, Firmicutes and Proteobacteria. High-concentrate diet significantly increased the abundance of Prevotella, and decreased the abundance of Paraprevotella, Sporobacter, Ruminococcus and Treponema than HF. Compared with HC, HCN had a trend to decrease the percentage of Prevotella, and to increase the abundance of Succiniclasticum, Acetivibrio and Treponema. Increasing concentrate ratio could decrease ruminal pH value, and change the ruminal microbial composition. Adding niacin in HC could increase the ruminal pH value, alter the ruminal microbial composition.

  1. Implications of Industrial Processing Strategy on Cellulosic Ethanol Production at High Solids Concentrations

    DEFF Research Database (Denmark)

    Cannella, David

    The production of cellulosic ethanol is a biochemical process of not edible biomasses which contain the cellulose. The process involves the use of enzymes to hydrolyze the cellulose in fermentable sugars to finally produce ethanol via fermentative microorganisms (i.e. yeasts). These biomasses...... are the leftover of agricultural productions (straws), not edible crops (giant reed) or wood, thus the ethanol so produced is also called second generation (or 2G ethanol), which differs from the first generation produced from starch (sugar beets mostly). In the industrial production of cellulosic ethanol high...... solids strategy resulted critical for its cost effectiveness: high concentration of initial biomass it will lead to high concentration of the final product (ethanol), thus more convenient to isolate. This thesis investigate the implementation of a high solids loading concept into cellulosic ethanol...

  2. Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

    International Nuclear Information System (INIS)

    Lowry, N.J.

    1998-01-01

    This report provides results of an analytical study of high concentration PCB paint in a shutdown nuclear test reactor located at the US Department of Energy's Savannah River Site (SRS). The study was designed to obtain data relevant for an evaluation of potential hazards associated with the use of and exposure to such paints

  3. Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, N.J.

    1998-10-21

    This report provides results of an analytical study of high concentration PCB paint in a shutdown nuclear test reactor located at the US Department of Energy's Savannah River Site (SRS). The study was designed to obtain data relevant for an evaluation of potential hazards associated with the use of and exposure to such paints.

  4. Resting serum concentration of high-sensitivity C-reactive protein ...

    African Journals Online (AJOL)

    Resting serum concentration of high-sensitivity C-reactive protein (hs-CRP) in sportsmen and untrained male adults. F.A. Niyi-Odumosu, O. A. Bello, S.A. Biliaminu, B.V. Owoyele, T.O. Abu, O.L. Dominic ...

  5. The preparation and ethanol fermentation of high-concentration sugars from steam-explosion corn stover.

    Science.gov (United States)

    Xie, Hui; Wang, Fengqin; Yin, Shuangyao; Ren, Tianbao; Song, Andong

    2015-05-01

    In the field of biofuel ethanol, high-concentration- reducing sugars made from cellulosic materials lay the foundation for high-concentration ethanol fermentation. In this study, corn stover was pre-treated in a process combining chemical methods and steam explosion; the cellulosic hydrolyzed sugars obtained by fed-batch saccharification were then used as the carbon source for high-concentration ethanol fermentation. Saccharomyces cerevisiae 1308, Angel yeast, and Issatchenkia orientalis were shake-cultured with Pachysolen tannophilus P-01 for fermentation. Results implied that the ethanol yields from the three types of mixed strains were 4.85 g/100 mL, 4.57 g/100 mL, and 5.02 g/100 mL (separately) at yield rates of 91.6, 89.3, and 92.2%, respectively. Therefore, it was inferred that shock-fermentation using mixed strains achieved a higher ethanol yield at a greater rate in a shorter fermentation period. This study provided a theoretical basis and technical guidance for the fermentation of industrial high-concentrated cellulosic ethanol.

  6. Mapping the Life Satisfaction of Adolescents in Hong Kong Secondary Schools with High Ethnic Concentration

    Science.gov (United States)

    Yuen, Yuet Mui Celeste; Lee, Moosung

    2016-01-01

    The present study aims to map the life satisfaction of adolescents from ethnic minority/immigrant backgrounds in schools with high concentrations of co-ethnic peers by comparing them with their mainstream counterparts in Hong Kong. The life satisfaction of 1,522 students was measured by the validated Multidimensional Students' Life Satisfaction…

  7. Production of ethanol from wheat straw by pretreatment and fermentation at high dry matter concentrations

    NARCIS (Netherlands)

    Groenestijn, J.W. van; Slomp, R.S.

    2011-01-01

    High concentrations of substrate and product are important for the economy of second-generation bioethanol production. By a dilute acid thermal pretreatment of large pieces of relatively dry wheat straw using a novel rapid heating method, followed by fed-batch preliquefaction with hydrolytic

  8. Decadal and seasonal trends of nutrient concentration and export from highly managed coastal catchments.

    Science.gov (United States)

    Wan, Yongshan; Wan, Lei; Li, Yuncong; Doering, Peter

    2017-05-15

    Understanding anthropogenic and hydro-climatic influences on nutrient concentrations and export from highly managed catchments often necessitates trend detection using long-term monitoring data. This study analyzed the temporal trend (1979-2014) of total nitrogen (TN) and total phosphorus (TP) concentrations and export from four adjacent coastal basins in south Florida where land and water resources are highly managed through an intricate canal network. The method of integrated seasonal-trend decomposition using LOESS (LOcally weighted regrESSion) was employed for trend detection. The results indicated that long-term trends in TN and TP concentrations (increasing/decreasing) varied with basins and nutrient species, reflecting the influence of basin specific land and water management practices. These long-term trends were intervened by short-term highs driven by high rainfall and discharges and lows associated with regional droughts. Seasonal variations in TP were more apparent than for TN. Nutrient export exhibited a chemostatic behavior for TN from all the basins, largely due to the biogenic nature of organic N associated with the ubiquity of organic materials in the managed canal network. Varying degrees of chemodynamic export was present for TP, reflecting complex biogeochemical responses to the legacy of long-term fertilization, low soil P holding capacity, and intensive stormwater management. The anthropogenic and hydro-climatic influences on nutrient concentration and export behavior had great implications in nutrient loading abatement strategies for aquatic ecosystem restoration of the downstream receiving waterbody. Published by Elsevier Ltd.

  9. Innovative encapsulated oxygen-releasing beads for bioremediation of BTEX at high concentration in groundwater.

    Science.gov (United States)

    Lin, Chi-Wen; Wu, Chih-Hung; Guo, Pei-Yu; Chang, Shih-Hsien

    2017-12-15

    Both a low concentration of dissolved oxygen and the toxicity of a high concentration of BTEX inhibit the bioremediation of BTEX in groundwater. A novel method of preparing encapsulated oxygen-releasing beads (encap-ORBs) for the biodegradation of BTEX in groundwater was developed. Experimental results show that the integrality and oxygen-releasing capacity of encap-ORBs exceeded those of ORBs. The use of polyvinyl alcohol (PVA) with high M.W. to prepare encap-ORBs improved their integrality. The encap-ORBs effectively released oxygen for 128 days. High concentration of BTEX (480 mg L -1 ) inhibited the biodegradation by the free cells. Immobilization of degraders in the encap-ORB alleviated the inhibition. Scanning electron microscope analysis reveals that the BTEX degraders grew on the surface of encap-ORB after bioremediation. The above results indicate that the encap-ORBs were effective in the bioremediation of BTEX at high concentration in groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Real-Time in Vivo Detection of H2O2 Using Hyperpolarized 13C-Thiourea.

    Science.gov (United States)

    Wibowo, Arif; Park, Jae Mo; Liu, Shie-Chau; Khosla, Chaitan; Spielman, Daniel M

    2017-07-21

    Reactive oxygen species (ROS) are essential cellular metabolites widely implicated in many diseases including cancer, inflammation, and cardiovascular and neurodegenerative disorders. Yet, ROS signaling remains poorly understood, and their measurements are a challenge due to high reactivity and instability. Here, we report the development of 13 C-thiourea as a probe to detect and measure H 2 O 2 dynamics with high sensitivity and spatiotemporal resolution using hyperpolarized 13 C magnetic resonance spectroscopic imaging. In particular, we show 13 C-thiourea to be highly polarizable and to possess a long spin-lattice relaxation time (T 1 ), which enables real-time monitoring of ROS-mediated transformation. We also demonstrate that 13 C-thiourea reacts readily with H 2 O 2 to give chemically distinguishable products in vitro and validate their detection in vivo in a mouse liver. This study suggests that 13 C-thiourea is a promising agent for noninvasive detection of H 2 O 2 in vivo. More broadly, our findings outline a viable clinical application for H 2 O 2 detection in patients with a range of diseases.

  11. Quality of care and patient satisfaction in hospitals with high concentrations of black patients.

    Science.gov (United States)

    Brooks-Carthon, J Margo; Kutney-Lee, Ann; Sloane, Douglas M; Cimiotti, Jeannie P; Aiken, Linda H

    2011-09-01

    To examine the influence of nursing-specifically nurse staffing and the nurse work environment-on quality of care and patient satisfaction in hospitals with varying concentrations of Black patients. Cross-sectional secondary analysis of 2006-2007 nurse survey data collected across four states (Florida, Pennsylvania, New Jersey, and California), the Hospital Consumer Assessment of Healthcare Providers and Systems survey, and administrative data. Global analysis of variance and linear regression models were used to examine the association between the concentration of Black patients on quality measures (readiness for discharge, patient or family complaints, health care-associated infections) and patient satisfaction, before and after accounting for nursing and hospital characteristics. Nurses working in hospitals with higher concentrations of Blacks reported poorer confidence in patients' readiness for discharge and more frequent complaints and infections. Patients treated in hospitals with higher concentrations of Blacks were less satisfied with their care. In the fully adjusted regression models for quality and patient satisfaction outcomes, the effects associated with the concentration of Blacks were explained in part by nursing and structural hospital characteristics. This study demonstrates a relationship between nursing, structural hospital characteristics, quality of care, and patient satisfaction in hospitals with high concentrations of Black patients. Consideration of nursing factors, in addition to other important hospital characteristics, is critical to understanding and improving quality of care and patient satisfaction in minority-serving hospitals. © 2011 Sigma Theta Tau International.

  12. High concentrations of thiosulfate in scala tympani perilymph after systemic administration in the guinea pig.

    Science.gov (United States)

    Pierre, Pernilla Videhult; Engmér, Cecilia; Wallin, Inger; Laurell, Göran; Ehrsson, Hans

    2009-02-01

    High concentrations of the antioxidant thiosulfate reach scala tympani perilymph after i.v. administration in the guinea pig. Thiosulfate concentrations in perilymph remain elevated longer than in blood. This warrants further studies on the possibility of obtaining otoprotection by thiosulfate administration several hours before that of cisplatin without compromising the anticancer effect caused by cisplatin inactivation in the blood compartment. Thiosulfate may reduce cisplatin-induced ototoxicity, presumably by oxidative stress relief and formation of inactivate platinum complexes. This study aimed to explore to what extent thiosulfate reaches scala tympani perilymph after systemic administration in the guinea pig. Scala tympani perilymph (1 microl) was aspirated from the basal turn of each cochlea up to 3 h after thiosulfate administration (103 mg/kg b.w., i.v.). Blood samples were also taken. Thiosulfate was quantified by HPLC and fluorescence detection. Substantial thiosulfate concentrations were found in perilymph. The area under the concentration-time curve for thiosulfate in perilymph and blood was 3100 microMxmin and 6300 microMxmin, respectively. The highest thiosulfate concentrations in perilymph were found at the first sampling at about 10 min. Due to a more rapid elimination from blood, perilymph concentrations exceeded those of blood towards the end of the experiment.

  13. Concentration-Induced Association in a Protein System Caused by a Highly Directional Patch Attraction.

    Science.gov (United States)

    Li, Weimin; Persson, Björn A; Lund, Mikael; Bergenholtz, Johan; Zackrisson Oskolkova, Malin

    2016-09-01

    Self-association of the protein lactoferrin is studied in solution using small-angle X-ray scattering techniques. Effective static structure factors have been shown to exhibit either a monotonic or a nonmonotonic dependence on protein concentration in the small wavevector limit, depending on salt concentration. The behavior correlates with a nonmonotonic dependence of the second virial coefficient on salt concentration, such that a maximum appears in the structure factor at a low protein concentration when the second virial coefficient is negative and close to a minimum. The results are interpreted in terms of an integral equation theory with explicit dimers, formulated by Wertheim, which provides a consistent framework able to explain the behavior in terms of a monomer-dimer equilibrium that appears because of a highly directional patch attraction. Short attraction ranges preclude trimer formation, which explains why the protein system behaves as if it were subject to a concentration-dependent isotropic protein-protein attraction. Superimposing an isotropic interaction, comprising screened Coulomb repulsion and van der Waals attraction, on the patch attraction allows for a semiquantitative modeling of the complete transition pathway from monomers in the dilute limit to monomer-dimer systems at somewhat higher protein concentrations.

  14. Physiological epidermal growth factor concentrations activate high affinity receptors to elicit calcium oscillations.

    Directory of Open Access Journals (Sweden)

    Béatrice Marquèze-Pouey

    Full Text Available Signaling mediated by the epidermal growth factor (EGF is crucial in tissue development, homeostasis and tumorigenesis. EGF is mitogenic at picomolar concentrations and is known to bind its receptor on high affinity binding sites depending of the oligomerization state of the receptor (monomer or dimer. In spite of these observations, the cellular response induced by EGF has been mainly characterized for nanomolar concentrations of the growth factor, and a clear definition of the cellular response to circulating (picomolar concentrations is still lacking. We investigated Ca2+ signaling, an early event in EGF responses, in response to picomolar doses in COS-7 cells where the monomer/dimer equilibrium is unaltered by the synthesis of exogenous EGFR. Using the fluo5F Ca2+ indicator, we found that picomolar concentrations of EGF induced in 50% of the cells a robust oscillatory Ca2+ signal quantitatively similar to the Ca2+ signal induced by nanomolar concentrations. However, responses to nanomolar and picomolar concentrations differed in their underlying mechanisms as the picomolar EGF response involved essentially plasma membrane Ca2+ channels that are not activated by internal Ca2+ store depletion, while the nanomolar EGF response involved internal Ca2+ release. Moreover, while the picomolar EGF response was modulated by charybdotoxin-sensitive K+ channels, the nanomolar response was insensitive to the blockade of these ion channels.

  15. Physiological epidermal growth factor concentrations activate high affinity receptors to elicit calcium oscillations.

    Science.gov (United States)

    Marquèze-Pouey, Béatrice; Mailfert, Sébastien; Rouger, Vincent; Goaillard, Jean-Marc; Marguet, Didier

    2014-01-01

    Signaling mediated by the epidermal growth factor (EGF) is crucial in tissue development, homeostasis and tumorigenesis. EGF is mitogenic at picomolar concentrations and is known to bind its receptor on high affinity binding sites depending of the oligomerization state of the receptor (monomer or dimer). In spite of these observations, the cellular response induced by EGF has been mainly characterized for nanomolar concentrations of the growth factor, and a clear definition of the cellular response to circulating (picomolar) concentrations is still lacking. We investigated Ca2+ signaling, an early event in EGF responses, in response to picomolar doses in COS-7 cells where the monomer/dimer equilibrium is unaltered by the synthesis of exogenous EGFR. Using the fluo5F Ca2+ indicator, we found that picomolar concentrations of EGF induced in 50% of the cells a robust oscillatory Ca2+ signal quantitatively similar to the Ca2+ signal induced by nanomolar concentrations. However, responses to nanomolar and picomolar concentrations differed in their underlying mechanisms as the picomolar EGF response involved essentially plasma membrane Ca2+ channels that are not activated by internal Ca2+ store depletion, while the nanomolar EGF response involved internal Ca2+ release. Moreover, while the picomolar EGF response was modulated by charybdotoxin-sensitive K+ channels, the nanomolar response was insensitive to the blockade of these ion channels.

  16. Plasma methylphenidate concentrations in youths treated with high-dose osmotic release oral system formulation.

    Science.gov (United States)

    Stevens, Jonathan R; George, Robert A; Fusillo, Steven; Stern, Theodore A; Wilens, Timothy E

    2010-02-01

    Children and adolescents are being treated increasingly for attention-deficit/hyperactivity disorder (ADHD) with a variety of stimulants in higher than Food and Drug Administration (FDA)-approved doses and in combination with other medications. We sought to determine methylphenidate (MPH) concentrations in children and adolescents treated with high-dose, extended-release osmotic release oral system (OROS) MPH plus concomitant medications, and to examine MPH concentrations with respect to the safety and tolerability of treatment. Plasma MPH concentrations were measured by liquid chromatography-mass spectrometry 4-5 hours after administration of medication in a sample of youths diagnosed with ADHD. These youths were treated naturalistically with higher than FDA-approved doses of OROS MPH in addition to their concomitant medications. Markers of safety and tolerability (e.g., measures of blood pressure and heart rate) were also examined. Among the 17 patients (with a mean age of 16.2 +/- 2 years and a mean number of concurrent medications of 2.23 +/- 0.94), the mean plasma MPH concentration was 28 +/- 9.1 ng/mL, despite a mean daily dose of OROS MPH of 169 +/- 5 mg (3.0 +/- 0.8 mg/kg per day). No patient had a plasma MPH level >or=50 ng/mL or clinical signs of stimulant toxicity. No correlation was found between plasma MPH concentrations and OROS MPH dose or changes in vital signs. High-dose OROS MPH, used in combination with other medications, was not associated with either unusually elevated plasma MPH concentrations or with clinically meaningful changes in vital signs. Study limitations include a single time-point sampling of MPH concentrations, a small sample size, and a lack of outcome measures to address treatment effectiveness.

  17. Investigation on the effect of thermal resistances on a highly concentrated photovoltaic-thermoelectric hybrid system

    International Nuclear Information System (INIS)

    Zhang, Jin; Xuan, Yimin

    2016-01-01

    Highlights: • The highly concentrated PV-TE hybrid system is studied. • The performances of different cooling systems are analyzed and compared. • Sandwiching a copper plate between the PV and TE can improve the efficiency. • Four thermal design principles of the system are proposed. - Abstract: A thermal analysis of a highly concentrated photovoltaic-thermoelectric (PV-TE) hybrid system is carried out in this paper. Both the output power and the temperature distribution in the hybrid system are calculated by means of a three-dimensional numerical model. Three possible approaches for designing the highly concentrated PV-TE hybrid system are presented by analyzing the thermal resistance of the whole system. First, the sensitivity analysis shows that the thermal resistance between the TE module and the environment has a more great effect on the output power than the thermal resistance between the PV and the TE. The influence of the natural convection and the radiation can be ignored for the highly concentrated PV-TE hybrid system. Second, it is necessary to sandwich a copper plate between the PV and the TE for decreasing the thermal resistance between the PV and the TE. The role of the copper plate is to improve the temperature uniformity. Third, decreasing the area of PV cells can improve the efficiency of the highly concentrated PV-TE hybrid system. It should be pointed out that decreasing the area of PV cells also increases the total thermal resistance, but the raise of the efficiency is caused by the reduction of the heat transfer rate of the system. Therefore, the principle of minimizing the total thermal resistance may not be suitable for optimizing the area of PV cells.

  18. Influence of vibration on structure rheological properties of a highly concentrated suspension

    Science.gov (United States)

    Ouriev Uriev, Boris N.; Uriev, Naum B.

    2005-08-01

    The influence of mechanical vibration on the flow properties of a highly concentrated multiphase food system is explored in this work. An experimental set-up was designed and adapted to a conventional rotational rheometer with precise rheological characterization capability. A number of calibration tests were performed prior to fundamental experiments with a highly concentrated chocolate suspension. Also, the prediction of wall slippage in shear flow under vibration was evaluated. Analysis of the boundary conditions shows that no side effects such as wall slippage or the Taylor effect were present during the shear experiment under vibration. It was found that superposition of mechanical vibration and shear flow radically decreases the shear viscosity. Comparison between reference shear viscosities at specified shear rates and those measured under vibration shows considerable differences in flow properties. Conversion of the behaviour of the concentrated suspension from strongly shear-thinning to Newtonian flow is reported. Also, the appearance of vibration-induced dilatancy as a new phenomenon is described. It is suggested to relate such phenomena to the non-equilibrium between structure formation and disintegration under vibration and hydrodynamic forces of shear flow. The influence of vibration on structure formation can be well observed during measurement of the yield value of the chocolate suspension under vibration. Comparison with reference data shows how sensitive the structure of the concentrated suspension is to vibration in general. The effects and observations revealed provide a solid basis for further fundamental investigations of structure formation regularities in the flow of any highly concentrated system. The results also show the technological potential for non-conventional treatment of concentrated, multiphase systems.

  19. Plasma PCSK9 concentrations during an oral fat load and after short term high-fat, high-fat high-protein and high-fructose diets

    Directory of Open Access Journals (Sweden)

    Cariou Bertrand

    2013-01-01

    Full Text Available Abstract Background PCSK9 (Proprotein Convertase Subtilisin Kexin type 9 is a circulating protein that promotes hypercholesterolemia by decreasing hepatic LDL receptor protein. Under non interventional conditions, its expression is driven by sterol response element binding protein 2 (SREBP2 and follows a diurnal rhythm synchronous with cholesterol synthesis. Plasma PCSK9 is associated to LDL-C and to a lesser extent plasma triglycerides and insulin resistance. We aimed to verify the effect on plasma PCSK9 concentrations of dietary interventions that affect these parameters. Methods We performed nutritional interventions in young healthy male volunteers and offspring of type 2 diabetic (OffT2D patients that are more prone to develop insulin resistance, including: i acute post-prandial hyperlipidemic challenge (n=10, ii 4 days of high-fat (HF or high-fat/high-protein (HFHP (n=10, iii 7 (HFruc1, n=16 or 6 (HFruc2, n=9 days of hypercaloric high-fructose diets. An acute oral fat load was also performed in two patients bearing the R104C-V114A loss-of-function (LOF PCSK9 mutation. Plasma PCSK9 concentrations were measured by ELISA. For the HFruc1 study, intrahepatocellular (IHCL and intramyocellular lipids were measured by 1H magnetic resonance spectroscopy. Hepatic and whole-body insulin sensitivity was assessed with a two-step hyperinsulinemic-euglycemic clamp (0.3 and 1.0 mU.kg-1.min-1. Findings HF and HFHP short-term diets, as well as an acute hyperlipidemic oral load, did not significantly change PCSK9 concentrations. In addition, post-prandial plasma triglyceride excursion was not altered in two carriers of PCSK9 LOF mutation compared with non carriers. In contrast, hypercaloric 7-day HFruc1 diet increased plasma PCSK9 concentrations by 28% (p=0.05 in healthy volunteers and by 34% (p=0.001 in OffT2D patients. In another independent study, 6-day HFruc2 diet increased plasma PCSK9 levels by 93% (p Conclusions Plasma PCSK9 concentrations vary

  20. Design and Optimization of Fresnel Lens for High Concentration Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Lei Jing

    2014-01-01

    Full Text Available A practical optimization design is proposed, in which the solar direct light spectrum and multijunction cell response range are taken into account in combination, particularly for the Fresnel concentrators with a high concentration and a small aspect ratio. In addition, the change of refractive index due to temperature variation in outdoor operation conditions is also considered in the design stage. The calculation results show that this novel Fresnel lens achieves an enhancement of energy efficiency of about 10% compared with conventional Fresnel lens for a given solar spectrum, solar cell response, and corrected sunshine hours of different ambient temperature intervals.

  1. Enhanced Cycling Stability of Rechargeable Li-O2 Batteries Using High Concentration Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin; Xu, Wu; Yan, Pengfei; Sun, Xiuliang; Bowden, Mark E.; Read, Jeffrey; Qian, Jiangfeng; Mei, Donghai; Wang, Chong M.; Zhang, Jiguang

    2016-01-26

    The electrolyte stability against reactive reduced-oxygen species is crucial for the development of rechargeable Li-O2 batteries. In this work, we systematically investigated the effect of lithium salt concentration in 1,2-dimethoxyethane (DME)-based electrolytes on the cycling stability of Li-O2 batteries. Cells with high concentration electrolyte illustrate largely enhanced cycling stability under both the full discharge/charge (2.0-4.5 V vs. Li/Li+) and the capacity limited (at 1,000 mAh g-1) conditions. These cells also exhibit much less reaction-residual on the charged air electrode surface, and much less corrosion to the Li metal anode. The density functional theory calculations are conducted on the molecular orbital energies of the electrolyte components and the Gibbs activation barriers for superoxide radical anion to attack DME solvent and Li+-(DME)n solvates. In a highly concentrated electrolyte, all DME molecules have been coordinated with salt and the C-H bond scission of a DME molecule becomes more difficult. Therefore, the decomposition of highly concentrated electrolyte in a Li-O2 battery can be mitigated and both air-cathodes and Li-metal anodes exhibits much better reversibility. As a results, the cyclability of Li-O2 can be largely improved.

  2. Spectral and Concentration Sensitivity of Multijunction Solar Cells at High Temperature: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Daniel J.; Steiner, Myles A.; Perl, Emmett E.; Simon, John

    2017-06-14

    We model the performance of two-junction solar cells at very high temperatures of ~400 degrees C and beyond for applications such as hybrid PV/solar-thermal power production, and identify areas in which the design and performance characteristics behave significantly differently than at more conventional near-room-temperature operating conditions. We show that high-temperature operation reduces the sensitivity of the cell efficiency to spectral content, but increases the sensitivity to concentration, both of which have implications for energy yield in terrestrial PV applications. For other high-temperature applications such as near-sun space missions, our findings indicate that concentration may be a useful tool to enhance cell efficiency.

  3. Influence of a High-Pressure Comminution Technology on Concentrate Yields in Copper Ore Flotation Processes

    Directory of Open Access Journals (Sweden)

    Saramak D.

    2014-10-01

    Full Text Available The article concerns the issues of flotation process effectiveness in relationship to the operating conditions of a high-pressure comminution process course. Experimental programme covering a flotation laboratory batch tests was a verification technique of a high-pressure crushing operations course. The most favorable values of flotation concentrate weight recoveries were obtained for the pressing force 6 kN and 4% of the feed moisture. It was also determined the model of the concentrate weight recovery as a function of pressing force in the press and feed moisture content. This model was the basis for the optimization of effects of copper ore flotation processes preceded in high-pressure crushing operation in roller presses.

  4. The role of silicon interstitials in the deactivation and reactivation of high concentration boron profiles

    Energy Technology Data Exchange (ETDEWEB)

    Aboy, Maria [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain)]. E-mail: marabo@tel.uva.es; Pelaz, Lourdes [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Marques, Luis A. [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Lopez, Pedro [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Barbolla, Juan [Campus Miguel Delibes, University of Valladolid, 47011 Valladolid (Spain); Venezia, V.C. [Philips Research Leuven, Leuven (Belgium); Duffy, R. [Philips Research Leuven, Leuven (Belgium); Griffin, Peter B. [Stanford University, Stanford, CA (United States)

    2004-12-15

    Boron cluster formation and dissolution in high concentration B profiles and the role of Si interstitials in these processes are analyzed by kinetic non-lattice Monte Carlo atomistic simulations. For this purpose, we use theoretical structures as simplifications of boron implants into preamorphized Si, followed by low-temperature solid phase epitaxial (SPE) regrowth or laser thermal annealing process. We observe that in the presence of high B concentrations (above 10{sup 20} cm{sup -3}), significant deactivation occurs during high temperature anneal, even in the presence of only equilibrium Si interstitials. The presence of additional Si interstitials from an end of range (EOR) damage region accelerates the deactivation process and makes B deactivation slightly higher. We show that B deactivation and reactivation processes can be clearly correlated to the evolution of Si interstitial defects at the EOR. The minimum level of activation occurs when the Si interstitial defects at EOR dissolve or form very stable defects.

  5. Phenomenon of energy concentration in super-high energy γ-hadron families

    International Nuclear Information System (INIS)

    Dai Zhiqiang; Xue Liang; Li Jinyu; Zhang Xueyao; Feng Cunfeng; Fu Yu; Li Jie; Cao Peiyuan; Zhang Naijian; He Mao; Wang Chengrui; Ren Jingru; Lu Suiling

    2000-01-01

    The family events observed with iron emulsion chambers at Mt. Kanbala are analyzed and compared with the simulations by the COSMOS code and CORSIKA code respectively. A detailed study on the production of super-high energy γ-hadron families with energy concentration behavior is carried out. The preliminary conclusions are: 1) the energy concentration behavior of super-high energy γ-hadron families is the external embodiment of high energy central shower clusters contained in the families. 2) the mean lateral spread of these clusters is about 0.37 cm. 3) the frequency of this phenomenon appeared under the conditions of R≤10 mm and X 10 ≥90% is (20.5 +- 3.1)%. 4) compared to the COSMOS code based on the phenomenological multi-cluster model, the simulation by the CORSIKA code that adopts SIBYLL model is closer to the analytical results of experiment

  6. High concentrations of H2O2 make aerobic glycolysis energetically more favourable than cellular respiration.

    Directory of Open Access Journals (Sweden)

    Hamid R Molavian

    2016-08-01

    Full Text Available Since the original observation of the Warburg Effect in cancer cells, over eight decades ago, the major question of why aerobic glycolysis is favored over oxidative phosphorylation has remained unresolved. An understanding of this phenomenon may well be the key to the development of more effective cancer therapies. In this paper, we use a semi-empirical method to throw light on this puzzle. We show that aerobic glycolysis is in fact energetically more favorable than oxidative phosphorylation for concentrations of peroxide (H2O2 above some critical threshold value. The fundamental reason for this is the activation and high engagement of the pentose phosphate pathway (PPP in response to the production of reactive oxygen species H2O2 by mitochondria and the high concentration of H2O2 (produced by mitochondria and other sources. This makes oxidative phosphorylation an inefficient source of energy since it leads (despite high levels of ATP production to a concomitant high energy consumption in order to respond to the hazardous waste products resulting from cellular processes associated with this metabolic pathway. We also demonstrate that the high concentration of H2O2 results in an increased glucose consumption, and also increases the lactate production in the case of glycolysis.

  7. Quality evaluation of moluodan concentrated pill using high-performance liquid chromatography fingerprinting coupled with chemometrics.

    Science.gov (United States)

    Tao, Lingyan; Zhang, Qing; Wu, Yongjiang; Liu, Xuesong

    2016-12-01

    In this study, a fast and effective high-performance liquid chromatography method was developed to obtain a fingerprint chromatogram and quantitative analysis simultaneously of four indexes including gallic acid, chlorogenic acid, albiflorin and paeoniflorin of the traditional Chinese medicine Moluodan Concentrated Pill. The method was performed by using a Waters X-bridge C 18 reversed phase column on an Agilent 1200S high-performance liquid chromatography system coupled with diode array detection. The mobile phase of the high-performance liquid chromatography method was composed of 20 mmol/L phosphate solution and acetonitrile with a 1 mL/min eluent velocity, under a detection temperature of 30°C and a UV detection wavelength of 254 nm. After the methodology validation, 16 batches of Moluodan Concentrated Pill were analyzed by this high-performance liquid chromatography method and both qualitative and quantitative evaluation results were achieved by similarity analysis, principal component analysis and hierarchical cluster analysis. The results of these three chemometrics were in good agreement and all indicated that batch 10 and batch 16 showed significant differences with the other 14 batches. This suggested that the developed high-performance liquid chromatography method could be applied in the quality evaluation of Moluodan Concentrated Pill. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Vasopressin activates Akt/mTOR pathway in smooth muscle cells cultured in high glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Daniela K.; Brenet, Marianne; Muñoz, Vanessa C.; Burgos, Patricia V.; Villanueva, Carolina I. [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Figueroa, Carlos D. [Department of Anatomy, Histology and Pathology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); González, Carlos B., E-mail: cbgonzal@uach.cl [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2013-11-29

    Highlights: •AVP induces mTOR phosphorylation in A-10 cells cultured in high glucose concentration. •The mTOR phosphorylation is mediated by the PI3K/Akt pathway activation. •The AVP-induced mTOR phosphorylation inhibited autophagy and stimulated cell proliferation. -- Abstract: Mammalian target of rapamycin (mTOR) complex is a key regulator of autophagy, cell growth and proliferation. Here, we studied the effects of arginine vasopressin (AVP) on mTOR activation in vascular smooth muscle cells cultured in high glucose concentration. AVP induced the mTOR phosphorylation in A-10 cells grown in high glucose, in contrast to cells cultured in normal glucose; wherein, only basal phosphorylation was observed. The AVP-induced mTOR phosphorylation was inhibited by a PI3K inhibitor. Moreover, the AVP-induced mTOR activation inhibited autophagy and increased thymidine incorporation in cells grown in high glucose. This increase was abolished by rapamycin which inhibits the mTORC1 complex formation. Our results suggest that AVP stimulates mTOR phosphorylation by activating the PI3K/Akt signaling pathway and, subsequently, inhibits autophagy and raises cell proliferation in A-10 cells maintained in high glucose concentration.

  9. Characterization and optimization of the visualization performance of continuous flow overhauser DNP hyperpolarized water MRI: Inversion recovery approach.

    Science.gov (United States)

    Terekhov, Maxim; Krummenacker, Jan; Denysenkov, Vasyl; Gerz, Kathrin; Prisner, Thomas; Schreiber, Laura Maria

    2016-03-01

    Overhauser dynamic nuclear polarization (DNP) allows the production of liquid hyperpolarized substrate inside the MRI magnet bore as well as its administration in continuous flow mode to acquire MR images with enhanced signal-to-noise ratio. We implemented inversion recovery preparation in order to improve contrast-to-noise ratio and to quantify the overall imaging performance of Overhauser DNP-enhanced MRI. The negative enhancement created by DNP in combination with inversion recovery (IR) preparation allows canceling selectively the signal originated from Boltzmann magnetization and visualizing only hyperpolarized fluid. The theoretical model describing gain of MR image intensity produced by steady-state continuous flow DNP hyperpolarized magnetization was established and proved experimentally. A precise quantification of signal originated purely from DNP hyperpolarization was achieved. A temperature effect on longitudinal relaxation had to be taken into account to fit experimental results with numerical prediction. Using properly adjusted IR preparation, the complete zeroing of thermal background magnetization was achieved, providing an essential increase of contrast-to-noise ratio of DNP-hyperpolarized water images. To quantify and optimize the steady-state conditions for MRI with continuous flow DNP, an approach similar to that incorporating transient-state thermal magnetization equilibrium in spoiled fast field echo imaging sequences can be used. © 2015 Wiley Periodicals, Inc.

  10. Circulating adiponectin concentration and body composition are altered in response to high-intensity interval training.

    Science.gov (United States)

    Shing, Cecilia M; Webb, Jessica J; Driller, Matthew W; Williams, Andrew D; Fell, James W

    2013-08-01

    Adiponectin influences metabolic adaptations that would prove beneficial to endurance athletes, and yet to date there is little known about the response of adiponectin concentrations to exercise, and, in particular, the response of this hormone to training in an athlete population. This study aimed to determine the response of plasma adiponectin concentrations to acute exercise after 2 different training programs and to determine the influence of the training on body composition. Seven state-level representative rowers (age: 19 ± 1.2 years [mean ± SD], height: 1.77 ± 0.10 m, body mass: 74.0 ± 10.7 kg, VO2peak 62.1 ± 7.0 ml·kg·min) participated in the double-blind, randomized crossover investigation. Rowers performed an incremental graded exercise test before and after completing 4 weeks of high-intensity interval ergometer training and 4 weeks of traditional ergometer rowing training. Rowers' body composition was assessed at baseline and after each training program. Significant increases in plasma adiponectin concentration occurred in response to maximal exercise after completion of the high-intensity interval training (p = 0.016) but not after traditional ergometer rowing training (p = 0.69). The high-intensity interval training also resulted in significant increases in mean 4-minute power output (p = 0.002) and VO2peak (p = 0.05), and a decrease in body fat percentage (p = 0.022). Mean 4-minute power output, VO2peak, and body fat percentage were not significantly different after 4 weeks of traditional ergometer rowing training (p > 0.05). Four weeks of high-intensity interval training is associated with an increase in adiponectin concentration in response to maximal exercise and a reduction in body fat percentage. The potential for changes in adiponectin concentration to reflect positive training adaptations and athlete performance level should be further explored.

  11. Inhibition of raw starch digestion by one glucoamylase preparation from black Aspergillus at high enzyme concentration

    Energy Technology Data Exchange (ETDEWEB)

    Saka, B C; Veda, S

    1981-09-01

    Raw starch digestion by glucoamylase I (Ab. G-I) preparation from black Aspergillus was inhibited significantly at relatively high concentration of the enzyme. The properties of this enzyme were studied together with those of another glucoamylase I (Nor. G-I), also from black Aspergillus. The two glucoamylases do not differ so much in their physico-chemical properties such as molecular weight, pH and thermal stability, pH and temperature optimum, substrate specificity, debranching activity, isoelectric point etc. The adsorption rate of both enzymes on raw starch increased by the increase of enzyme concentration. The raw starch digestion rate by adsorbed Ab. G-I, however, was decreased with the increase of concentration of enzyme whereas the same was increased in case of Nor. G-I. The inhibitory effect was weaker at 60 deg. Celcius or above. (Refs. 11).

  12. Advanced Oxidation Processes (AOPs for Refinery Wastewater Treatment Contains High Phenol Concentration

    Directory of Open Access Journals (Sweden)

    Azizah Alif Nurul

    2018-01-01

    Full Text Available Petroleum Refinery wastewater is characterized by a high phenol content. Phenol is toxic and resistant to biological processes for treatment of the petroleum refinery wastewater. The combination of an AOP and a biological process can be used for treatment of the refinery wastewater. It is necessary to conduct a study to determine the appropriate condition of AOP to meet the phenol removal level. Two AOP configurations were investigated: H2O2 / UV and H2O2 / UV / O3. From each process samples, COD, phenol and pH were measured. The oxidation was carried out until the targeted phenol concentration of treated effluent were obtained. The better result obtained by using process H2O2 / UV / O3 with the H2O2 concentration 1000 ppm. After 120 minutes, the final target has been achieved in which phenol concentration of 37.5 mg/L or phenol degradation of 93.75%.

  13. Diffusion of ion-implanted B in high concentration P- and As-doped silicon

    International Nuclear Information System (INIS)

    Fair, R.B.; Pappas, P.N.

    1975-01-01

    The diffusion of ion-implanted B in Si in the presence of a uniform background of high concentration P or As was studied by correlating numerical profile calculations with profiles determined by secondary-ion mass spectrometry (SIMS). Retarded B diffusion is observed in both As- and P-doped Si, consistent with the effect of the local Fermi-level position in the Si band gap on B diffusivity, D/sub B/. It is shown that D/sub B/ is linearly dependent on the free hole concentration, p, over the range 0.1 less than p/n/sub ie/ less than 30, where n/sub ie/ is the effective intrinsic electron concentration. This result does not depend on the way in which the background dopant has been introduced (implantation predeposition or doped-oxide source), nor the type of dopant used (P or As). (U.S.)

  14. Effect of Temperature on Chinese Rice Wine Brewing with High Concentration Presteamed Whole Sticky Rice

    Directory of Open Access Journals (Sweden)

    Dengfeng Liu

    2014-01-01

    Full Text Available Production of high quality Chinese rice wine largely depends on fermentation temperature. However, there is no report on the ethanol, sugars, and acids kinetics in the fermentation mash of Chinese rice wine treated at various temperatures. The effects of fermentation temperatures on Chinese rice wine quality were investigated. The compositions and concentrations of ethanol, sugars, glycerol, and organic acids in the mash of Chinese rice wine samples were determined by HPLC method. The highest ethanol concentration and the highest glycerol concentration both were attained at the fermentation mash treated at 23°C. The highest peak value of maltose (90 g/L was obtained at 18°C. Lactic acid and acetic acid both achieved maximum values at 33°C. The experimental results indicated that temperature contributed significantly to the ethanol production, acid flavor contents, and sugar contents in the fermentation broth of the Chinese rice wines.

  15. Effect of Temperature on Chinese Rice Wine Brewing with High Concentration Presteamed Whole Sticky Rice

    Science.gov (United States)

    Zhang, Hong-Tao; Xiong, Weili; Hu, Jianhua; Xu, Baoguo; Lin, Chi-Chung; Xu, Ling; Jiang, Lihua

    2014-01-01

    Production of high quality Chinese rice wine largely depends on fermentation temperature. However, there is no report on the ethanol, sugars, and acids kinetics in the fermentation mash of Chinese rice wine treated at various temperatures. The effects of fermentation temperatures on Chinese rice wine quality were investigated. The compositions and concentrations of ethanol, sugars, glycerol, and organic acids in the mash of Chinese rice wine samples were determined by HPLC method. The highest ethanol concentration and the highest glycerol concentration both were attained at the fermentation mash treated at 23°C. The highest peak value of maltose (90 g/L) was obtained at 18°C. Lactic acid and acetic acid both achieved maximum values at 33°C. The experimental results indicated that temperature contributed significantly to the ethanol production, acid flavor contents, and sugar contents in the fermentation broth of the Chinese rice wines. PMID:24672788

  16. Biodegradation of high concentrations of phenol by baker’s yeast in anaerobic sequencing batch reactor

    Directory of Open Access Journals (Sweden)

    Ali Asghar Najafpoor

    2015-06-01

    Full Text Available Background: Phenol, as a pure substance, is used in many fields because of its disinfectant, germicidal, local anesthetic, and peptizing properties. Aqueous solutions of phenol are produced as waste in industries and discharged into the environment. Therefore, elevated concentrations of phenol may be found in air or water because of industrial discharge or the use of phenolic products. Method: The strains of Saccharomyces cerevisiae used in this project were natural strains previously purchased from Razavy company. They were grown at 30°C on Petri plates containing yeast extract glucose (YGC and then purified by being spread onto new plates, and isolated colonies were obtained. These colonies provided the basis of selection. Prepared strains were applied in anaerobic sequencing batch reactors (ASBRs as first seed. The experiment conditions were optimized using response surface methodology (RSM. After the determined runs were performed using Design-Expert software, data were analyzed using mentioned software as well. Results: This study evaluated the capability of baker’s yeast to remove phenol in high concentrations. The tested strains showed excellent tolerance to phenol toxicity at concentrations up to 6100 mg/L. Study of the batch degradation process showed that the phenol removal rate could exceed 99.9% in 24 hours at a concentration of 1000 mg/L. The results showed catechol is the first intermediate product of phenol degradation. In survey results of the Design–Expert software, R2 and Adeq precision were 0.97 and 25.65, respectively. Conclusion: The results demonstrated that ASBR performs robustly under variable influent concentrations of inhibitory compounds. The high removal performance despite the high phenol concentration may be a result of reactor operating strategies. Based on the progressive increase of inlet phenol concentration, allowing for an enhanced biomass acclimation in a short time, results at the microbiological levels

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

    Directory of Open Access Journals (Sweden)

    Ichim Christine V

    2011-08-01

    Full Text Available Abstract 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

  18. Performance analysis of high-concentrated multi-junction solar cells in hot climate

    Science.gov (United States)

    Ghoneim, Adel A.; Kandil, Kandil M.; Alzanki, Talal H.; Alenezi, Mohammad R.

    2018-03-01

    Multi-junction concentrator solar cells are a promising technology as they can fulfill the increasing energy demand with renewable sources. Focusing sunlight upon the aperture of multi-junction photovoltaic (PV) cells can generate much greater power densities than conventional PV cells. So, concentrated PV multi-junction solar cells offer a promising way towards achieving minimum cost per kilowatt-hour. However, these cells have many aspects that must be fixed to be feasible for large-scale energy generation. In this work, a model is developed to analyze the impact of various atmospheric factors on concentrator PV performance. A single-diode equivalent circuit model is developed to examine multi-junction cells performance in hot weather conditions, considering the impacts of both temperature and concentration ratio. The impacts of spectral variations of irradiance on annual performance of various high-concentrated photovoltaic (HCPV) panels are examined, adapting spectra simulations using the SMARTS model. Also, the diode shunt resistance neglected in the existing models is considered in the present model. The present results are efficiently validated against measurements from published data to within 2% accuracy. Present predictions show that the single-diode model considering the shunt resistance gives accurate and reliable results. Also, aerosol optical depth (AOD) and air mass are most important atmospheric parameters having a significant impact on HCPV cell performance. In addition, the electrical efficiency (η) is noticed to increase with concentration to a certain concentration degree after which it decreases. Finally, based on the model predictions, let us conclude that the present model could be adapted properly to examine HCPV cells' performance over a broad range of operating conditions.

  19. Serum vitamin E concentrations among highly functioning hip fracture patients are higher than in nonfracture controls.

    Science.gov (United States)

    D'Adamo, Christopher R; Shardell, Michelle D; Hicks, Gregory E; Orwig, Denise L; Hochberg, Marc C; Semba, Richard D; Yu-Yahiro, Janet A; Ferrucci, Luigi; Magaziner, Jay S; Miller, Ram R

    2011-03-01

    fracture patients demonstrated higher vitamin E concentrations. Thus, the relatively high degree of function among this cohort of hip fracture patients may explain their higher-than-expected vitamin E concentrations. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Enhanced excitatory input to MCH neurons during developmental period of high food intake is mediated by GABA

    Science.gov (United States)

    Li, Ying; van den Pol, Anthony N.

    2010-01-01

    In contrast to the local axons of GABA neurons of the cortex and hippocampus, lateral hypothalamic neurons containing melanin concentrating hormone (MCH) and GABA send long axons throughout the brain and play key roles in energy homeostasis and mental status. In adults, MCH neurons maintain a hyperpolarized membrane potential and most of the synaptic input is inhibitory. In contrast, we found that developing MCH neurons received substantially more excitatory synaptic input. Based on gramicidicin-perforated patch recordings in hypothalamic slices from MCH-GFP transgenic mice, we found that GABA was the primary excitatory synaptic transmitter in embryonic and neonatal ages up to postnatal day 10. Surprisingly, glutamate assumed only a minor excitatory role, if any. GABA plays a complex role in developing MCH neurons, with its actions conditionally dependent on a number of factors. GABA depolarization could lead to an increase in spikes either independently or in summation with other depolarizing stimuli, or alternately, depending on the relative timing of other depolarizing events, could lead to shunting inhibition. The developmental shift from depolarizing to hyperpolarizing occurred later in the dendrites than in the cell body. Early GABA depolarization was based on a Cl− dependent inward current. An interesting secondary depolarization in mature neurons that followed an initial hyperpolarization was based on a bicarbonate mechanism. Thus during the early developmental period when food consumption is high, MCH neurons are more depolarized than in the adult, and an increased level of excitatory synaptic input to these orexigenic cells is mediated by GABA. PMID:19955372

  1. Fluidized bed combustion of single coal char particles at high CO{sub 2} concentration

    Energy Technology Data Exchange (ETDEWEB)

    Scala, F.; Chirone, R. [CNR, Naples (Italy)

    2010-12-15

    Combustion of single coal char particles was studied at 850{sup o}C in a lab-scale fluidized bed at high CO{sub 2} concentration, typical of oxyfiring conditions. The burning rate of the particles was followed as a function of time by continuously measuring the outlet CO and O{sub 2} concentrations. Some preliminary evaluations on the significance of homogeneous CO oxidation in the reactor and of carbon gasification by CO{sub 2} in the char were also carried out. Results showed that the carbon burning rate increases with oxygen concentration and char particle size. The particle temperature is approximately equal to that of the bed up to an oxygen concentration of 2%, but it is considerably higher for larger oxygen concentrations. Both CO{sub 2} gasification of char and homogeneous CO oxidation are not negligible. The gasification reaction rate is slow and it is likely to be controlled by intrinsic kinetics. During purely gasification conditions the extent of carbon loss due to particle attrition by abrasion (estimated from the carbon mass balance) appears to be much more important than under combustion conditions.

  2. Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

    Science.gov (United States)

    Voichick, Nicholas; Topping, David J.; Griffiths, Ronald E.

    2018-03-01

    Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator-prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples) are necessary to

  3. Novel bioevaporation process for the zero-discharge treatment of highly concentrated organic wastewater.

    Science.gov (United States)

    Yang, Benqin; Zhang, Lei; Lee, Yongwoo; Jahng, Deokjin

    2013-10-01

    A novel process termed as bioevaporation was established to completely evaporate wastewater by metabolic heat released from the aerobic microbial degradation of the organic matters contained in the highly concentrated organic wastewater itself. By adding the glucose solution and ground food waste (FW) into the biodried sludge bed, the activity of the microorganisms in the biodried sludge was stimulated and the water in the glucose solution and FW was evaporated. As the biodegradable volatile solids (BVS) concentration in wastewater increased, more heat was produced and the water removal ratio increased. When the volatile solids (VS) concentrations of both glucose and ground FW were 120 g L(-1), 101.7% and 104.3% of the added water was removed, respectively, by completely consuming the glucose and FW BVS. Therefore, the complete removal of water and biodegradable organic contents was achieved simultaneously in the bioevaporation process, which accomplished zero-discharge treatment of highly concentrated organic wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. High Pb concentration stress on Typha latifolia growth and Pb removal in microcosm wetlands.

    Science.gov (United States)

    Han, Jianqiu; Chen, Fengzhen; Zhou, Yumei; Wang, Chaohua

    2015-01-01

    When constructed wetlands are used to treat high-Pb wastewater, Pb may become a stress to wetland plants, which subsequently reduces treatment performance and the other ecosystem services. To facilitate the design and operation of constructed wetlands for treatment of Pb-rich wastewater, we investigated the irreversible inhibitory level of Pb for Typha latifolia through experiments in microcosm wetlands. Seven horizontal subsurface flow constructed wetlands were built with rectangular plastic tanks and packed with marble chips and sand. All wetlands were transplanted with nine stems of Typha latifolia each. The wetlands were batch operated in a greenhouse with artificial wastewater (10 L each) for 12 days. Influent to the seven wetlands had different concentrations of Pb: 0 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 200 mg/L, and 500 mg/L, respectively. The results suggested that leaf chlorophyll relative content, relative growth rate, photosynthetic characteristics, activities of superoxide dismutase, peroxidase, and content of malondialdehyde were not affected when initial Pb concentration was at 100 mg/L and below. But when initial Pb concentration was above 100 mg/L, all of them were seriously affected. We conclude that high Pb concentrations wastewater could inhibit the growth of Typha latifolia and decrease the removal rate of wetlands.

  5. Investigation on the improved radiation hardness of silicon detectors with high oxygen concentration

    CERN Document Server

    Moll, Michael; Lindström, G

    2000-01-01

    We present an investigation on the influence of the oxygen concentration on radiation-induced changes in the effective doping concentration of silicon detectors. Diodes fabricated from silicon with interstitial oxygen content ranging from below 2*10/sup 14/ to 9*10/sup 17/ cm/sup -3/ have been irradiated with fast neutrons up to a fluence of 2*10/sup 15/ cm/sup -2/. Our main interest focused on the so-called stable damage component in the change of the effective doping concentration being of prime importance for the application of silicon detectors in high-energy physics experiments. We demonstrate, that with a high oxygen enrichment the donor removal is appreciably reduced, reaching a value of only 10601130f the initial doping concentration for [O/sub i/]=9*10/sup 17/ cm/sup -3/, while for normal detector grade material with [O/sub i/] below 5*10/sup 16/ cm /sup -3/ that value is 60-90Furthermore, we show that the fluence proportional introduction of stable acceptors is independent of the oxygen concentratio...

  6. Concentrate Supplement Modifies the Feeding Behavior of Simmental Cows Grazing in Two High Mountain Pastures.

    Science.gov (United States)

    Romanzin, Alberto; Corazzin, Mirco; Piasentier, Edi; Bovolenta, Stefano

    2018-05-16

    During grazing on Alpine pastures, the use of concentrates in dairy cows' diet leads to a reduction of the environmental sustainability of farms, and influences the selective pressure on some plant species. In order to minimize the use of concentrates, it is imperative to obtain data on the grazing behavior of cows. The aim of this study was to assess the effect of concentrate levels on the behavior of dairy cows during grazing. One hundred and ten lactating Italian Simmental cows, that sequentially grazed two pastures characterized by Poion alpinae (Poion) and Seslerion caeruleae (Seslerion) alliance, were considered. For each pasture, eight cows were selected and assigned to two groups: High and Low, supplemented with 4 kg/head/d, and 1 kg/head/d of concentrate respectively. Cows were equipped with a noseband pressure sensor and a pedometer (RumiWatch system, ITIN-HOCH GmbH) to assess grazing, ruminating, and walking behavior. In addition, the plant selection of the animals was assessed. On Poion, increased supplement intake caused a more intense selection of legumes, without affecting feeding and walking times. On Seslerion, grazing time was higher in Low than High. Grazing management in alpine region must take into account the great variability of pastures that largely differ from a floristic and nutritional point of view.

  7. Concentrate Supplement Modifies the Feeding Behavior of Simmental Cows Grazing in Two High Mountain Pastures

    Directory of Open Access Journals (Sweden)

    Alberto Romanzin

    2018-05-01

    Full Text Available During grazing on Alpine pastures, the use of concentrates in dairy cows’ diet leads to a reduction of the environmental sustainability of farms, and influences the selective pressure on some plant species. In order to minimize the use of concentrates, it is imperative to obtain data on the grazing behavior of cows. The aim of this study was to assess the effect of concentrate levels on the behavior of dairy cows during grazing. One hundred and ten lactating Italian Simmental cows, that sequentially grazed two pastures characterized by Poion alpinae (Poion and Seslerion caeruleae (Seslerion alliance, were considered. For each pasture, eight cows were selected and assigned to two groups: High and Low, supplemented with 4 kg/head/d, and 1 kg/head/d of concentrate respectively. Cows were equipped with a noseband pressure sensor and a pedometer (RumiWatch system, ITIN-HOCH GmbH to assess grazing, ruminating, and walking behavior. In addition, the plant selection of the animals was assessed. On Poion, increased supplement intake caused a more intense selection of legumes, without affecting feeding and walking times. On Seslerion, grazing time was higher in Low than High. Grazing management in alpine region must take into account the great variability of pastures that largely differ from a floristic and nutritional point of view.

  8. High Concentrations of Measles Neutralizing Antibodies and High-Avidity Measles IgG Accurately Identify Measles Reinfection Cases

    Science.gov (United States)

    Rota, Jennifer S.; Hickman, Carole J.; Mercader, Sara; Redd, Susan; McNall, Rebecca J.; Williams, Nobia; McGrew, Marcia; Walls, M. Laura; Rota, Paul A.; Bellini, William J.

    2016-01-01

    In the United States, approximately 9% of the measles cases reported from 2012 to 2014 occurred in vaccinated individuals. Laboratory confirmation of measles in vaccinated individuals is challenging since IgM assays can give inconclusive results. Although a positive reverse transcription (RT)-PCR assay result from an appropriately timed specimen can provide confirmation, negative results may not rule out a highly suspicious case. Detection of high-avidity measles IgG in serum samples provides laboratory evidence of a past immunologic response to measles from natural infection or immunization. High concentrations of measles neutralizing antibody have been observed by plaque reduction neutralization (PRN) assays among confirmed measles cases with high-avidity IgG, referred to here as reinfection cases (RICs). In this study, we evaluated the utility of measuring levels of measles neutralizing antibody to distinguish RICs from noncases by receiver operating characteristic curve analysis. Single and paired serum samples with high-avidity measles IgG from suspected measles cases submitted to the CDC for routine surveillance were used for the analysis. The RICs were confirmed by a 4-fold rise in PRN titer or by RT-quantitative PCR (RT-qPCR) assay, while the noncases were negative by both assays. Discrimination accuracy was high with serum samples collected ≥3 days after rash onset (area under the curve, 0.953; 95% confidence interval [CI], 0.854 to 0.993). Measles neutralizing antibody concentrations of ≥40,000 mIU/ml identified RICs with 90% sensitivity (95% CI, 74 to 98%) and 100% specificity (95% CI, 82 to 100%). Therefore, when serological or RT-qPCR results are unavailable or inconclusive, suspected measles cases with high-avidity measles IgG can be confirmed as RICs by measles neutralizing antibody concentrations of ≥40,000 mIU/ml. PMID:27335386

  9. Hyperpolarization-activated current (In is reduced in hippocampal neurons from Gabra5-/- mice.

    Directory of Open Access Journals (Sweden)

    Robert P Bonin

    Full Text Available Changes in the expression of γ-aminobutyric acid type A (GABAA receptors can either drive or mediate homeostatic alterations in neuronal excitability. A homeostatic relationship between α5 subunit-containing GABAA (α5GABAA receptors that generate a tonic inhibitory conductance, and HCN channels that generate a hyperpolarization-activated cation current (Ih was recently described for cortical neurons, where a reduction in Ih was accompanied by a reciprocal increase in the expression of α5GABAA receptors resulting in the preservation of dendritosomatic synaptic function. Here, we report that in mice that lack the α5 subunit gene (Gabra5-/-, cultured embryonic hippocampal pyramidal neurons and ex vivo CA1 hippocampal neurons unexpectedly exhibited a decrease in Ih current density (by 40% and 28%, respectively, compared with neurons from wild-type (WT mice. The resting membrane potential and membrane hyperpolarization induced by blockade of Ih with ZD-7288 were similar in cultured WT and Gabra5-/- neurons. In contrast, membrane hyperpolarization measured after a train of action potentials was lower in Gabra5-/- neurons than in WT neurons. Also, membrane impedance measured in response to low frequency stimulation was greater in cultured Gabra5-/- neurons. Finally, the expression of HCN1 protein that generates Ih was reduced by 41% in the hippocampus of Gabra5-/- mice. These data indicate that loss of a tonic GABAergic inhibitory conductance was followed by a compensatory reduction in Ih. The results further suggest that the maintenance of resting membrane potential is preferentially maintained in mature and immature hippocampal neurons through the homeostatic co-regulation of structurally and biophysically distinct cation and anion channels.

  10. A comparison of quantitative methods for clinical imaging with hyperpolarized (13)C-pyruvate.

    Science.gov (United States)

    Daniels, Charlie J; McLean, Mary A; Schulte, Rolf F; Robb, Fraser J; Gill, Andrew B; McGlashan, Nicholas; Graves, Martin J; Schwaiger, Markus; Lomas, David J; Brindle, Kevin M; Gallagher, Ferdia A

    2016-04-01

    Dissolution dynamic nuclear polarization (DNP) enables the metabolism of hyperpolarized (13)C-labelled molecules, such as the conversion of [1-(13)C]pyruvate to [1-(13)C]lactate, to be dynamically and non-invasively imaged in tissue. Imaging of this exchange reaction in animal models has been shown to detect early treatment response and correlate with tumour grade. The first human DNP study has recently been completed, and, for widespread clinical translation, simple and reliable methods are necessary to accurately probe the reaction in patients. However, there is currently no consensus on the most appropriate method to quantify this exchange reaction. In this study, an in vitro system was used to compare several kinetic models, as well as simple model-free methods. Experiments were performed using a clinical hyperpolarizer, a human 3 T MR system, and spectroscopic imaging sequences. The quantitative methods were compared in vivo by using subcutaneous breast tumours in rats to examine the effect of pyruvate inflow. The two-way kinetic model was the most accurate method for characterizing the exchange reaction in vitro, and the incorporation of a Heaviside step inflow profile was best able to describe the in vivo data. The lactate time-to-peak and the lactate-to-pyruvate area under the curve ratio were simple model-free approaches that accurately represented the full reaction, with the time-to-peak method performing indistinguishably from the best kinetic model. Finally, extracting data from a single pixel was a robust and reliable surrogate of the whole region of interest. This work has identified appropriate quantitative methods for future work in the analysis of human hyperpolarized (13)C data. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

  11. Ovariectomy increases the participation of hyperpolarizing mechanisms in the relaxation of rat aorta.

    Directory of Open Access Journals (Sweden)

    Ana Sagredo

    Full Text Available This study examines the downstream NO release pathway and the contribution of different vasodilator mediators in the acetylcholine-induced response in rat aorta 5-months after the loss of ovarian function. Aortic segments from ovariectomized and control female Sprague-Dawley rats were used to measure: the levels of superoxide anion, the superoxide dismutases (SODs activity, the cGMP formation, the cGMP-dependent protein kinase (PKG activity and the involvement of NO, cGMP, hydrogen peroxide and hyperpolarizing mechanisms in the ACh-induced relaxation. The results showed that ovariectomy did not alter ACh-induced relaxation; incubation with L-NAME, a NO synthase inhibitor, decreased the ACh-induced response to a lesser extent in aorta from ovariectomized than from control rats, while ODQ, a guanylate cyclase inhibitor, decreased that response to a similar extent; the blockade of hyperpolarizing mechanisms, by precontracting arteries with KCl, decreased the ACh-induced response to a greater extent in aortas from ovariectomized than those from control rats; catalase, that decomposes hydrogen peroxide, decreased the ACh-induced response only in aorta from ovariectomized rats. In addition, ovariectomy increased superoxide anion levels and SODs activity, decreased cGMP formation and increased PKG activity. Despite the increased superoxide anion and decreased cGMP in aorta from ovariectomized rats, ACh-induced relaxation is maintained by the existence of hyperpolarizing mechanisms in which hydrogen peroxide participates. The greater contribution of hydrogen peroxide in ACh-induced relaxation is due to increased SOD activity, in an attempt to compensate for increased superoxide anion formation. Increased PKG activity could represent a redundant mechanism to ensure vasodilator function in the aorta of ovariectomized rats.

  12. Assessing the transport rate of hyperpolarized pyruvate and lactate from the intra- to the extracellular space.

    Science.gov (United States)

    Reineri, Francesca; Daniele, Valeria; Cavallari, Eleonora; Aime, Silvio

    2016-08-01

    The use of [1-(13) C]pyruvate hyperpolarized by means of dynamic nuclear polarization provides a direct way to track the metabolic transformations of this metabolite in vivo and in cell cultures. The identification of the intra- and extracellular contributions to the (13) C NMR resonances is not straightforward. In order to obtain information about the rate of pyruvate and lactate transport through the cellular membrane, we set up a method that relies on the sudden 'quenching' of the extracellular metabolites' signal. The paramagnetic Gd-tetraazacyclododecane triacetic acid (Gd-DO3A) complex was used to dramatically decrease the longitudinal relaxation time constants of the (13) C-carboxylate resonances of both pyruvate and lactate. When Gd-DO3A was added to an MCF-7 cellular culture, which had previously received a dose of hyperpolarized [1-(13) C]pyruvate, the contributions of the extracellular pyruvate and lactate signals were deleted. From the analysis of the decay curves of the (13) C-carboxylate resonances of pyruvate and lactate it was possible to extract information about the exchange rate of the two metabolites across the cellular membrane. In particular, it was found that, in the reported experimental conditions, the lactate transport from the intra- to the extracellular space is not much lower than the rate of lactate formation. The method reported herein is non-destructive and it could be translated to in vivo studies. It opens a route for the use of hyperpolarized pyruvate to assess altered activity of carboxylate transporter proteins that may occur in pathological conditions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. High Concentration of Melatonin Regulates Leaf Development by Suppressing Cell Proliferation and Endoreduplication in Arabidopsis.

    Science.gov (United States)

    Wang, Qiannan; An, Bang; Shi, Haitao; Luo, Hongli; He, Chaozu

    2017-05-05

    N -acetyl-5-methoxytryptamine (Melatonin), as a crucial messenger in plants, functions in adjusting biological rhythms, stress tolerance, plant growth and development. Several studies have shown the retardation effect of exogenous melatonin treatment on plant growth and development. However, the in vivo role of melatonin in regulating plant leaf growth and the underlying mechanism are still unclear. In this study, we found that high concentration of melatonin suppressed leaf growth in Arabidopsis by reducing both cell size and cell number. Further kinetic analysis of the fifth leaves showed that melatonin remarkably inhibited cell division rate. Additionally, flow cytometic analysis indicated that melatonin negatively regulated endoreduplication during leaf development. Consistently, the expression analysis revealed that melatonin regulated the transcriptional levels of key genes of cell cycle and ribosome. Taken together, this study suggests that high concentration of melatonin negatively regulated the leaf growth and development in Arabidopsis , through modulation of endoreduplication and the transcripts of cell cycle and ribosomal key genes.

  14. High pressure-temperature electrical conductivity of magnesiowustite as a function of iron oxide concentration

    Science.gov (United States)

    Li, Xiaoyuan; Jeanloz, Raymond

    1990-01-01

    The electrical conductivity of (Mg, Fe)O magnesiowustite containing 9 and 27.5 mol pct FeO has been measured at simultaneously high pressures (30-32 GPa) and temperatures using a diamond anvil cell heated with a continuous wave Nd:YAG laser and an external resistance heater. The conductivity depends strongly on the FeO concentration at both ambient and high pressures. At the pressures and temperatures of about 30 GPa and 2000 K, conditions expected in the lower mantle, the magnesiowustite containing 27.5 percent FeO is 3 orders of magnitude more conductive than that containing 9 percent FeO. The activation energy of magnesiowustite decreases with increasing iron concentration from 0.38 (+ or - 0.09) eV at 9 percent FeO to 0.29 (+ or - 0.05) eV at 27.5 percent FeO.

  15. High concentrations of cadmium, cerium and lanthanum in indoor air due to environmental tobacco smoke

    International Nuclear Information System (INIS)

    Böhlandt, Antje; Schierl, Rudolf; Diemer, Juergen; Koch, Christoph; Bolte, Gabriele; Kiranoglu, Mandy; Fromme, Hermann; Nowak, Dennis

    2012-01-01

    Background: Environmental tobacco smoke (ETS) is one of the most important sources for indoor air pollution and a substantial threat to human health, but data on the concentrations of the trace metals cerium (Ce) and lanthanum (La) in context with ETS exposure are scarce. Therefore the aim of our study was to quantify Ce and La concentrations in indoor air with high ETS load. Methods: In two subsequent investigations Ce, La and cadmium (Cd) in 3 smokers' (11 samples) and 7 non-smokers' (28 samples) households as well as in 28 hospitality venues in Southern Germany were analysed. Active sampling of indoor air was conducted continuously for seven days in every season in the smokers' and non-smokers' residences, and for 4 h during the main visiting hours in the hospitality venues (restaurants, pubs, and discotheques). Results: In terms of residences median levels of Cd were 0.1 ng/m 3 for non-smokers' and 0.8 ng/m 3 for smokers' households. Median concentrations of Ce were 0.4 ng/m 3 and 9.6 ng/m 3 , and median concentrations of La were 0.2 ng/m 3 and 5.9 ng/m 3 for non-smokers' and for smokers' households, respectively. In the different types of hospitality venues median levels ranged from 2.6 to 9.7 ng/m 3 for Cd, from 18.5 to 50.0 ng/m 3 for Ce and from 10.6 to 23.0 ng/m 3 for La with highest median levels in discotheques. Conclusions: The high concentrations of Ce and La found in ETS enriched indoor air of smokers' households and hospitality venues are an important finding as Ce and La are associated with adverse health effects and data on this issue are scarce. Further research on their toxicological, human and public health consequences is urgently required. - Highlights: ► We quantified cer, lanthanum and cadmium concentrations in indoor air. ► Cer and lanthanum concentrations were high in tobacco smoke enriched locations. ► Both elements can be considered as good markers for indoor air quality.

  16. Hyperpolarized 13C Urea Relaxation Mechanism Reveals Renal Changes in Diabetic Nephropathy

    DEFF Research Database (Denmark)

    Laustsen, Christoffer; Stokholm Nørlinger, Thomas; Christoffer Hansen, David

    2016-01-01

    Purpose: Our aim was to assess a novel 13C radial fast spin echo golden ratio single shot method for interrogating early renal changes in the diabetic kidney, using hyperpolarized (HP) [13C,15N2]urea as a T2 relaxation based contrast bio-probe. Methods: A novel HP 13C MR contrast experiment...... saturation level and the relaxation times were observed in the healthy controls. Conclusion: HP [13C,15N2]urea apparent T2 mapping may be a useful for interrogating local renal pO2 status and renal tissue alterations....

  17. Monitoring Cancer Response to Treatment with Hyperpolarized 13C MRS

    DEFF Research Database (Denmark)

    Eldirdiri, Abubakr

    , and the patient is exposed to ionizing radiation. The introduction of hyperpolarized 13C MRS has opened completely new possibilities to study the biochemical changes in disease processes. Numerous 13C-labeled compounds were proposed to interrogate various aspects of cancer cell metabolism. The aim of this study......Monitoring the cancer response to treatment, non-invasively, by medical imaging is a key element in the management of cancer. For patients undergoing treatment, it is crucial to determine responders from non-responders in order to guide treatment decisions. Currently, PET is the most widely used...

  18. Hypercalcemia and high parathyroid hormone-related protein concentration associated with malignant melanoma in a dog.

    Science.gov (United States)

    Pressler, Barrak M; Rotstein, David S; Law, Jerry M; Rosol, Thomas J; LeRoy, Bruce; Keene, Bruce W; Jackson, Mark W

    2002-07-15

    A 12-year-old Cocker Spaniel with an oral malignant melanoma was evaluated for progressive lethargy and anorexia. No metastases were identified during antemortem evaluation, but severe hypercalcemia was evident. Antemortem diagnostic testing failed to identify a cause for the hypercalcemia. No neoplasms other than the melanoma were identified on postmortem examination. Serum parathyroid hormone-related protein concentration was markedly high, and the melanoma had moderate to marked immunostaining for this protein. Paraneoplastic syndromes are rare in dogs with malignant melanoma.

  19. Effect of high concentration of molybdenum on the structure and properties of niobium

    International Nuclear Information System (INIS)

    Trekina, M.I.; Vasil'eva, E.V.

    1989-01-01

    The effect of alloying of 20,25 and 30 % Mo on the structure and mechanical properties of niobium is studied. It is shown that niobium alloying with molybdenum in the studied concentration leads to grain grinding, which increases with the molybdenum content growth in the alloy. The effective energy values of recrystallization activation of the studied niobium and molybdenum alloys are determined. The high hardness level at some plasticity and deformability of niobium alloy with 20 % Mo is established

  20. Natural radionuclides in food in an area with high concentrations of radionuclides

    International Nuclear Information System (INIS)

    Pereira, W.S.; Moraes, S.R.; Cavalcante, J.J.V.; Kelecom, A.; Silva, A.X. da; Lopez, J.M.; Filgueiras, R.; Carmo, A.S.

    2017-01-01

    Areas of high natural radiation expose the local population to doses greater than the world average. One of the routes of exposure is food intake. The activity concentration (AC) of 5 natural radionuclides in 7 types of foods was analyzed. The highest CA measured was 2.40 Bq.kg -1 for the U nat in the potato. The multivariate statistic identified two groups: (U nat e 232 Th) and [( 210 Pb and 228 Ra) and 226 Ra

  1. High concentrations of heavy metals in PM from ceramic factories of Southern Spain

    Science.gov (United States)

    Sánchez de la Campa, Ana M.; de la Rosa, Jesús D.; González-Castanedo, Yolanda; Fernández-Camacho, Rocío; Alastuey, Andrés; Querol, Xavier; Pio, Casimiro

    2010-06-01

    In this study, physicochemical characterization of Atmospheric Particulate Matter (PM) was performed in an urban-industrial site background (Bailén, Southern Spain), highly influenced by the impact of emission plumes from ceramic factories. This area is considered one of the towns with the highest PM 10 levels and average SO 2 concentration in Spain. A three stages methodology was used: 1) real-time measurements of levels of PM 10 and gaseous pollutants, and sampling of PM; 2) chemical characterization using ICP-MS, ICP-OES, CI and TOT, and source apportionment analysis (receptor modelling) of PM; and 3) chemical characterization of emission plumes derived from representative factories. High ambient air concentrations were found for most major components and trace elements compared with other industrialized towns in Spain. V and Ni are considered fingerprints of PM derived from the emissions of brick factories in this area, and were shown to be of particular interest. This highlights the high V and Ni concentrations in PM 10 (122 ngV/m 3 and 23.4 ngNi/m 3), with Ni exceeding the 2013 annual target value for the European Directive 2004/107/EC (20 ng/m 3). The methodology of this work can be used by Government departments responsible for Environment and Epidemiology in planning control strategies for improving air quality.

  2. Direct Analysis of Proteins from Solutions with High Salt Concentration Using Laser Electrospray Mass Spectrometry

    Science.gov (United States)

    Karki, Santosh; Shi, Fengjian; Archer, Jieutonne J.; Sistani, Habiballah; Levis, Robert J.

    2018-05-01

    The detection of lysozyme, or a mixture of lysozyme, cytochrome c, and myoglobin, from solutions with varying salt concentrations (0.1 to 250 mM NaCl) is compared using laser electrospray mass spectrometry (LEMS) and electrospray ionization-mass spectrometry (ESI-MS). Protonated protein peaks were observed up to a concentration of 250 mM NaCl in the case of LEMS. In the case of ESI-MS, a protein solution with salt concentration > 0.5 mM resulted in predominantly salt-adducted features, with suppression of the protonated protein ions. The constituents in the mixture of proteins were assignable up to 250 mM NaCl for LEMS and were not assignable above a NaCl concentration of 0.5 mM for ESI. The average sodium adducts () bound to the 7+ charge state of lysozyme for LEMS measurements from salt concentrations of 2.5, 25, 50, and 100 mM NaCl are 1.71, 5.23, 5.26, and 5.11, respectively. The conventional electrospray measurements for lysozyme solution containing salt concentrations of 0.1, 1, 2, and 5 mM NaCl resulted in of 2.65, 6.44, 7.57, and 8.48, respectively. LEMS displays an approximately two orders of magnitude higher salt tolerance in comparison with conventional ESI-MS. The non-equilibrium partitioning of proteins on the surface of the charged droplets is proposed as the mechanism for the high salt tolerance phenomena observed in the LEMS measurements. [Figure not available: see fulltext.

  3. Modulating fluorescence quantum yield of highly concentrated fluorescein using differently shaped green synthesized gold nanoparticles

    International Nuclear Information System (INIS)

    John, Jisha; Thomas, Lincy; Kurian, Achamma; George, Sajan D.

    2016-01-01

    The interaction of dye molecules with differently shaped nanoparticles is of great interest owing to the potential applications in areas of bioimaging, sensing and photodynamic therapy (biology) as well as solar cells (photonics) applications. For such applications, noble metallic nanoparticles are commonly employed to either enhance or quench the luminescence of a nearby fluorophore. However, in most of the studies, the dye concentration is limited to avoid self-quenching. This paper reports the influence of differently shaped gold nanoparticles (spherical, bean and star), prepared via green synthesis, on the emission behavior as well as on the fluorescence quantum yield of fluorescein dye at concentrations for which self-quenching occurs. The emission behavior is probed via laser based steady state fluorescence whereas quantum yield is measured using a dual beam laser based thermal lens technique. The experimentally observed fluorescence quenching with a concomitant increase in thermal lens signal in the vicinity of nanoparticles are explained in terms of nonradiative energy transfer between the donor and the acceptor. Further, the influence of pH of the prepared gold nanofluid on the absorption, emission as well as quantum yield are also accounted. These studies elucidate that even at high concentrations of dye, the gold nanoparticle and its shape clearly influences the optical properties of nearby dye molecules and thus can be exploited for future applications. - Highlights: • Green synthesis of differently shaped gold nanoparticles. • Tailoring emission properties of fluorescein with respect to nanoparticle concentration and shape. • Tailoring the quantum yield of highly concentrated fluorescein with nanoparticles.

  4. Investigation on the improved radiation hardness of silicon detectors with high oxygen concentration

    International Nuclear Information System (INIS)

    Moll, M.; Fretwurst, E.; Lindstroem, G.

    2000-01-01

    We present an investigation on the influence of the oxygen concentration on radiation-induced changes in the effective doping concentration of silicon detectors. Diodes fabricated from silicon with interstitial oxygen content ranging from below 2x10 14 to 9x10 17 cm -3 have been irradiated with fast neutrons up to a fluence of 2x10 15 cm -2 . Our main interest focused on the so-called stable damage component in the change of the effective doping concentration being of prime importance for the application of silicon detectors in high-energy physics experiments. We demonstrate, that with a high oxygen enrichment the donor removal is appreciably reduced, reaching a value of only 10% of the initial doping concentration for [O i ]=9x10 17 cm -3 , while for normal detector grade material with [O i ] below 5x10 16 cm -3 that value is 60-90%. Furthermore, we show that the fluence proportional introduction of stable acceptors is independent of the oxygen concentration with an averaged introduction rate of (1.49±0.03)x10 -2 cm -1 . Only one material was found exhibiting a significantly smaller value of about 0.6x10 -2 cm -1 and thus indicating the possibility to suppress the radiation-induced acceptor creation by material modification. Finally, we show that the experimental findings disagree in several important aspects with predictions made by microscopic defect kinetics models, leaving the physical background of some of the measured data as an open question

  5. On the peculiarities of LDA method in two-phase flows with high concentrations of particles

    Science.gov (United States)

    Poplavski, S. V.; Boiko, V. M.; Nesterov, A. U.

    2016-10-01

    Popular applications of laser Doppler anemometry (LDA) in gas dynamics are reviewed. It is shown that the most popular method cannot be used in supersonic flows and two-phase flows with high concentrations of particles. A new approach to implementation of the known LDA method based on direct spectral analysis, which offers better prospects for such problems, is presented. It is demonstrated that the method is suitable for gas-liquid jets. Owing to the progress in laser engineering, digital recording of spectra, and computer processing of data, the method is implemented at a higher technical level and provides new prospects of diagnostics of high-velocity dense two-phase flows.

  6. Estimating NOx emissions and surface concentrations at high spatial resolution using OMI

    Science.gov (United States)

    Goldberg, D. L.; Lamsal, L. N.; Loughner, C.; Swartz, W. H.; Saide, P. E.; Carmichael, G. R.; Henze, D. K.; Lu, Z.; Streets, D. G.

    2017-12-01

    In many instances, NOx emissions are not measured at the source. In these cases, remote sensing techniques are extremely useful in quantifying NOx emissions. Using an exponential modified Gaussian (EMG) fitting of oversampled Ozone Monitoring Instrument (OMI) NO2 data, we estimate NOx emissions and lifetimes in regions where these emissions are uncertain. This work also presents a new high-resolution OMI NO2 dataset derived from the NASA retrieval that can be used to estimate surface level concentrations in the eastern United States and South Korea. To better estimate vertical profile shape factors, we use high-resolution model simulations (Community Multi-scale Air Quality (CMAQ) and WRF-Chem) constrained by in situ aircraft observations to re-calculate tropospheric air mass factors and tropospheric NO2 vertical columns during summertime. The correlation between our satellite product and ground NO2 monitors in urban areas has improved dramatically: r2 = 0.60 in new product, r2 = 0.39 in operational product, signifying that this new product is a better indicator of surface concentrations than the operational product. Our work emphasizes the need to use both high-resolution and high-fidelity models in order to re-calculate vertical column data in areas with large spatial heterogeneities in NOx emissions. The methodologies developed in this work can be applied to other world regions and other satellite data sets to produce high-quality region-specific emissions estimates.

  7. Comparison of Low Concentration and High Concentration Arsenic Removal Techniques and Evaluation of Concentration of Arsenic in Ground Water: A Case Study of Lahore, Pakistan

    International Nuclear Information System (INIS)

    Yasar, Abdullah; Tabinda, Amtul Bari; Shahzadi, Uzma; Saleem, Pakeeza

    2014-01-01

    The main focus of this study was the evaluation of arsenic concentration in the ground water of Lahore at different depth and application of different mitigation techniques for arsenic removal. Twenty four hours of solar oxidation gives 90% of arsenic removal as compared to 8 hr. or 16 hr. Among oxides, calcium oxide gives 96% of As removal as compared to 93% by lanthanum oxide. Arsenic removal efficiency was up to 97% by ferric chloride, whereas 95% by alum. Activated alumina showed 99% removal as compared to 97% and 95% removal with bauxite and charcoal, respectively. Elemental analysis of adsorbents showed that the presence of phosphate and silica can cause a reduction of arsenic removal efficiency by activated alumina, bauxite and charcoal. This study has laid a foundation for further research on arsenic in the city of Lahore and has also provided suitable techniques for arsenic removal

  8. Comparison of Low Concentration and High Concentration Arsenic Removal Techniques and Evaluation of Concentration of Arsenic in Ground Water: A Case Study of Lahore, Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Yasar, Abdullah; Tabinda, Amtul Bari; Shahzadi, Uzma; Saleem, Pakeeza [GC University, Lahore (Pakistan)

    2014-10-15

    The main focus of this study was the evaluation of arsenic concentration in the ground water of Lahore at different depth and application of different mitigation techniques for arsenic removal. Twenty four hours of solar oxidation gives 90% of arsenic removal as compared to 8 hr. or 16 hr. Among oxides, calcium oxide gives 96% of As removal as compared to 93% by lanthanum oxide. Arsenic removal efficiency was up to 97% by ferric chloride, whereas 95% by alum. Activated alumina showed 99% removal as compared to 97% and 95% removal with bauxite and charcoal, respectively. Elemental analysis of adsorbents showed that the presence of phosphate and silica can cause a reduction of arsenic removal efficiency by activated alumina, bauxite and charcoal. This study has laid a foundation for further research on arsenic in the city of Lahore and has also provided suitable techniques for arsenic removal.

  9. A highly concentrated diet increases biogas production and the agronomic value of young bull's manure.

    Science.gov (United States)

    Mendonça Costa, Mônica Sarolli Silva de; Lucas, Jorge de; Mendonça Costa, Luiz Antonio de; Orrico, Ana Carolina Amorim

    2016-02-01

    The increasing demand for animal protein has driven significant changes in cattle breeding systems, mainly in feedlots, with the use of young bulls fed on diets richer in concentrate (C) than in forage (F). These changes are likely to affect animal manure, demanding re-evaluation of the biogas production per kg of TS and VS added, as well as of its agronomic value as a biofertilizer, after anaerobic digestion. Here, we determined the biogas production and agronomic value (i.e., the macronutrient concentration in the final biofertilizer) of the manure of young bulls fed on diets with more (80% C+20% F; 'HighC' diet) or less (65% C+35% F; 'LowC' diet) concentrate, evaluating the effects of temperature (25, 35, and 40°C) and the use of an inoculum, during anaerobic digestion. A total of 24 benchtop reactors were used, operating in a semi-continuous system, with a 40-day hydraulic retention time (HRT). The manure from animals given the HighC diet had the greatest potential for biogas production, when digested with the use of an inoculum and at 35 or 40°C (0.6326 and 0.6207m(3)biogas/kg volatile solids, or VS, respectively). We observed the highest levels of the macronutrients N, P, and K in the biofertilizer from the manure of animals given HighC. Our results show that the manure of young bulls achieves its highest potential for biogas production and agronomic value when animals are fed diets richer in concentrate, and that biogas production increases if digestion is performed at higher temperatures, and with the use of an inoculum. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. High fetal plasma adenosine concentration: a role for the fetus in preeclampsia?

    LENUS (Irish Health Repository)

    Espinoza, Jimmy

    2012-02-01

    OBJECTIVE: Clinical observations suggest a role for the fetus in the maternal manifestations of preeclampsia, but the possible signaling mechanisms remain unclear. This study compares the fetal plasma concentrations of adenosine from normal pregnancies with those from preeclampsia. STUDY DESIGN: This secondary data analysis included normal pregnancies (n = 27) and patients with preeclampsia (n = 39). Patients with preeclampsia were subclassified into patients with (n = 25) and without (n = 14) abnormal uterine artery Doppler velocimetry (UADV). RESULTS: Fetal plasma concentrations of adenosine were significantly higher in patients with preeclampsia (1.35 +\\/- 0.09 mumol\\/L) than in normal pregnancies (0.52 +\\/- 0.06 mumol\\/L; P < .0001). Fetal plasma concentrations of adenosine in patients with preeclampsia with abnormal UADV (1.78 +\\/- 0.15 mumol\\/L), but not with normal UADV (0.58 +\\/- 0.14 mumol\\/L), were significantly higher than in normal pregnancies (P < .0001). CONCLUSION: Patients with preeclampsia with sonographic evidence of chronic uteroplacental ischemia have high fetal plasma concentrations of adenosine.

  11. Origin of methane and sources of high concentrations in Los Angeles groundwater

    Science.gov (United States)

    Kulongoski, Justin; McMahon, Peter B.; Land, Michael; Wright, Michael; Johnson, Theodore; Landon, Matthew K.

    2018-01-01

    In 2014, samples from 37 monitoring wells at 17 locations, within or near oil fields, and one site >5 km from oil fields, in the Los Angeles Basin, California, were analyzed for dissolved hydrocarbon gas isotopes and abundances. The wells sample a variety of depths of an aquifer system composed of unconsolidated and semiconsolidated sediments under various conditions of confinement. Concentrations of methane in groundwater samples ranged from 0.002 to 150 mg/L—some of the highest concentrations reported in a densely populated urban area. The δ13C and δ2H of the methane ranged from −80.8 to −45.5 per mil (‰) and −249.8 to −134.9‰, respectively, and, along with oxidation‐reduction processes, helped to identify the origin of methane as microbial methanogenesis and CO2 reduction as its main formation pathway. The distribution of methane concentrations and isotopes is consistent with the high concentrations of methane in Los Angeles Basin groundwater originating from relatively shallow microbial production in anoxic or suboxic conditions. Source of the methane is the aquifer sediments rather than the upward migration or leakage of thermogenic methane associated with oil fields in the basin.

  12. The ability of fungus Mucor racemosus Fresenius to degrade high concentration of detergent

    Directory of Open Access Journals (Sweden)

    Jakovljević Violeta D.

    2014-01-01

    Full Text Available The ability of fungus Mucor racemosus Fresenius to decompose high concentration of commercial detergent (MERIX, Henkel, Serbia was investigated in this study. Fungus was cultivated in liquid growth medium by Czapek with addition of detergent at concentration 0.5% during 16 days. The biochemical changes of pH, redox potential, amount of free and total organic acids, and activity of alkaline phosphatase were evaluated by analysis of fermentation broth. Simultaneously, biodegradation percentage of anionic surfactant of tested detergent was confirmed by MBAS assay. At the same time, the influence of detergent on fungal growth and total dry weight biomass was determined. Detergent at concentration 0.5% influenced on decreasing of pH value and increasing of redox potential as well as increasing of free and total organic acids. Enzyme activity of alkaline phosphatase was reduced by detergent at concentration 0.5%. The fungus was decomposed about 62% of anionic surfactant during 16 day. Due to fungus was produced higher dry weight biomass (53% in relation to control. [Projekat Ministarstva nauke Republike Srbije, br. III 43004

  13. Imaging regional metabolic changes in the ischemic rat heart in vivo using hyperpolarized(1-13C)Pyruvate

    DEFF Research Database (Denmark)

    Lauritzen, Mette Hauge; Magnusson, Peter; Laustsen, Christoffer

    2017-01-01

    in the in vivo rat heart in an open-chest model of ischemia reperfusion. Hyperpolarized MRI enables new possibilities for evaluating changes in cardiac metabolism noninvasively and in real time, which potentially could be used for research to evaluate new treatments and metabolic interventions for myocardial......We evaluated the use of hyperpolarized 13C magnetic resonance imaging (MRI) in an open-chest rat model of myocardial infarction to image regional changes in myocardial metabolism. In total, 10 rats were examined before and after 30 minutes of occlusion of the left anterior descending coronary...

  14. Is a high serum copper concentration a risk factor for implantation failure?

    Science.gov (United States)

    Matsubayashi, Hidehiko; Kitaya, Kotaro; Yamaguchi, Kohei; Nishiyama, Rie; Takaya, Yukiko; Ishikawa, Tomomoto

    2017-08-10

    Copper-containing contraceptive devices may deposit copper ions in the endometrium, resulting in implantation failure. The deposition of copper ions in many organs has been reported in patients with untreated Wilson's disease. Since these patients sometimes exhibit subfertility and/or early pregnancy loss, copper ions were also considered to accumulate in the uterine endometrium. Wilson's disease patients treated with zinc successfully delivered babies because zinc interfered with the absorption of copper from the gastrointestinal tract. These findings led to the hypothesis that infertile patients with high serum copper concentrations may have implantation failure due to the excess accumulation of copper ions. The relationship between implantation (pregnancy) rates and serum copper concentrations has not yet been examined. The Japanese government recently stated that actual copper intake was higher among Japanese than needed. Therefore, the aim of the present study was to investigate whether serum copper concentrations are related to the implantation (pregnancy) rates of human embryos in vivo. We included 269 patients (age copper, and zinc concentrations were measured 16 days after the first date of progesterone replacement. We compared 96 women who were pregnant without miscarriage at 10 weeks of gestation (group P) and 173 women who were not pregnant (group NP). No significant differences were observed in age or BMI between the groups. Copper concentrations were significantly higher in group NP (average 193.2 μg/dL) than in group P (average 178.1 μg/dL). According to the area under the curve (AUC) on the receiver operating characteristic curve for the prediction of clinical pregnancy rates, the Cu/Zn ratio (AUC 0.64, 95% CI 0.54-0.71) was a better predictor than copper or zinc. When we set the cut-off as 1.59/1.60 for the Cu/Zn ratio, sensitivity, specificity, the positive predictive value, and negative predictive value were 0.98, 0.29, 0.71, and 0

  15. Highly Stable Operation of Lithium Metal Batteries Enabled by the Formation of a Transient High Concentration Electrolyte Layer

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Yan, Pengfei; Mei, Donghai; Engelhard, Mark H.; Cartmell, Samuel S.; Polzin, Bryant; Wang, Chong M.; Zhang, Jiguang; Xu, Wu

    2016-02-08

    Lithium (Li) metal has been extensively investigated as an anode for rechargeable battery applications due to its ultrahigh specific capacity and the lowest redox potential. However, significant challenges including dendrite growth and low Coulombic efficiency are still hindering the practical applications of rechargeable Li metal batteries. Here, we demonstrate that long-term cycling of Li metal batteries can be realized by the formation of a transient high concentration electrolyte layer near the surface of Li metal anode during high rate discharge process. The highly concentrated Li+ ions in this transient layer will immediately solvate with the available solvent molecules and facilitate the formation of a stable and flexible SEI layer composed of a poly(ethylene carbonate) framework integrated with other organic/inorganic lithium salts. This SEI layer largely suppresses the corrosion of Li metal anode by free organic solvents and enables the long-term operation of Li metal batteries. The fundamental findings in this work provide a new direction for the development and operation of Li metal batteries that could be operated at high current densities for a wide range of applications.

  16. Hydrogen-bonded structure in highly concentrated aqueous LiBr solutions

    International Nuclear Information System (INIS)

    Imano, Masahiro; Kameda, Yasuo; Usuki, Takeshi; Uemura, Osamu

    2001-01-01

    Neutron diffraction measurements were carried out for H/D isotopically substituted aqueous 10, 25 and 33 mol% LiBr solutions in order to obtain structural information on the intermolecular hydrogen bonds among water molecules in highly concentrated aqueous solutions. Observed scattering cross sections for D 2 O (99.9 % D), 0 H 2 O(35.9 % D) and 0-2 H 2 O(68.0 % D) solutions were combined to deduce partial structure factors, a HH (Q), a XH (Q) and a XX (Q) (X: O, Br and Li). The least squares fitting analysis was applied to the observed partial structure factors to determine the nearest neighbor interatomic distance, root-mean-square amplitude and coordination number. Intermolecular distances, r OH =1.91(1) A, r HH =2.38(1) A and r OO =3.02(1) A, between the nearest neighbor water molecules, were obtained for the 10 mol% LiBr solution. On the other hand, the intermolecular O···H interaction was found to almost disappear in concentrated 25 and 33 mol% LiBr solutions. The result implies that the hydrogen-bonded network is completely broken in highly concentrated aqueous LiBr solutions. (author)

  17. Analysis of serotonin concentrations in human milk by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Chiba, Takeshi; Maeda, Tomoji; Tairabune, Tomohiko; Tomita, Takashi; Sanbe, Atsushi; Takeda, Rika; Kikuchi, Akihiko; Kudo, Kenzo

    2017-03-25

    Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in milk volume homeostasis in the mammary gland during lactation; 5-HT in milk may also affect infant development. However, there are few reports on 5-HT concentrations in human breast milk. To address this issue, we developed a simple method based on high-performance liquid chromatography with fluorescence detection (HPLC-FD) for measuring 5-HT concentrations in human breast milk. Breast milk samples were provided by four healthy Japanese women. Calibration curves for 5-HT in each sample were prepared with the standard addition method between 5 and 1000 ng/ml, and all had correlation coefficients >0.999. The recovery of 5-HT was 96.1%-101.0%, with a coefficient of variation of 3.39%-8.62%. The range of 5-HT concentrations estimated from the calibration curves was 11.1-51.1 ng/ml. Thus, the HPLC-FD method described here can effectively extract 5-HT from human breast milk with high reproducibility. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Tailoring Microbial Electrochemical Cells for Production of Hydrogen Peroxide at High Concentrations and Efficiencies.

    Science.gov (United States)

    Young, Michelle N; Links, Mikaela J; Popat, Sudeep C; Rittmann, Bruce E; Torres, César I

    2016-12-08

    A microbial peroxide producing cell (MPPC) for H 2 O 2 production at the cathode was systematically optimized with minimal energy input. First, the stability of H 2 O 2 was evaluated using different catholytes, membranes, and catalyst materials. On the basis of these results, a flat-plate MPPC fed continuously using 200 mm NaCl catholyte at a 4 h hydraulic retention time was designed and operated, producing H 2 O 2 for 18 days. H 2 O 2 concentration of 3.1 g L -1 H 2 O 2 with 1.1 Wh g -1 H 2 O 2 power input was achieved in the MPPC. The high H 2 O 2 concentration was a result of the optimum materials selected. The small energy input was largely the result of the 0.5 cm distance between the anode and cathode, which reduced ionic transport losses. However, >50 % of operational overpotentials were due to the 4.5-5 pH unit difference between the anode and cathode chambers. The results demonstrate that a MPPC can continuously produce H 2 O 2 at high concentration by selecting compatible materials and appropriate operating conditions. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Leaching of copper concentrates with high arsenic content in chlorine-chloride media

    International Nuclear Information System (INIS)

    Herreros, O.; Fuentes, G.; Quiroz, R.; Vinals, J.

    2003-01-01

    This work reports the results of copper concentrates leaching which have high arsenic concepts (up to 2.5%). The treatments were carried out using chlorine that forms from sodium hypochlorite and sulphuric acid. The aim of this work is to obtain a solution having high copper content 4 to 6 g/l and 5 to 7 g/l free acid in order to submit it directly to a solvent extraction stage. In addition, this solution should have minimum content of arsenic and chloride ions. To carry out this investigation, an acrylic reactor was constructed where the leaching tests were made at constant temperature in a thermostatic bath under atmospheric pressure. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Typical variables were studied, such as leaching agent concentration, leaching time, pulp density and temperature among others. Some of the residues were analyzed by XRD and EPS. On the other hand, the solutions were analyzed by Atomic Absorption Spectroscopy. The results indicate solutions having the contents stated above can be obtained. (Author) 19 refs

  20. Research on high-temperature heat receiver in concentrated solar radiation system

    Directory of Open Access Journals (Sweden)

    Estera Przenzak

    2017-01-01

    Full Text Available The article presents the results of experimental and computer simulations studies of the high temperature heat receiver working in the concentrated solar radiation system. In order to study the radiation absorption process and heat exchange, the two types of computer simulations were carried out. The first one was used to find the best location for absorber in the concentrating installation. Ray Tracing Monte Carlo (RTMC method in Trace Pro software was used to perform the optical simulations. The results of these simulations were presented in the form of the solar radiation distribution map and chart. The data obtained in RTMC simulations were used as a second type boundary conditions for Computational Fluid Dynamics (CFD simulations. These studies were used to optimize the internal geometry of the receiver and also to select the most effective flow parameters of the working medium. In order to validate the computer simulations, high temperature heat receiver was tested in experimental conditions. The article presents the results of experimental measurements in the form of temperature, radiation intensity and power graphs. The tests were performed for varied flow rate and receiver location. The experimental and computer simulation studies presented in this article allowed to optimize the configuration of concentrating and heat receiving system.

  1. High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrator Application

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, Seth

    2012-09-12

    The High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrators project seeks to provide new photovoltaic cells for Concentrator Photovoltaics (CPV) Systems with higher cell efficiency, more favorable temperature coefficients and less sensitivity to changes in spectral distribution. The main objective of this project is to provide high efficiency III-V solar cells that will reduce the overall cost per Watt for power generation using CPV systems.This work is focused both on a potential near term application, namely the use of indium arsenide (InAs) QDs to spectrally "tune" the middle (GaAs) cell of a SOA triple junction device to a more favorable effective bandgap, as well as the long term goal of demonstrating intermediate band solar cell effects. The QDs are confined within a high electric field i-region of a standard GaAs solar cell. The extended absorption spectrum (and thus enhanced short circuit current) of the QD solar cell results from the increase in the sub GaAs bandgap spectral response that is achievable as quantum dot layers are introduced into the i-region. We have grown InAs quantum dots by OMVPE technique and optimized the QD growth conditions. Arrays of up to 40 layers of strain balanced quantum dots have been experimentally demonstrated with good material quality, low residual stain and high PL intensity. Quantum dot enhanced solar cells were grown and tested under simulated one sun AM1.5 conditions. Concentrator solar cells have been grown and fabricated with 5-40 layers of QDs. Testing of these devices show the QD cells have improved efficiency compared to baseline devices without QDs. Device modeling and measurement of thermal properties were performed using Crosslight APSYS. Improvements in a triple junction solar cell with the insertion of QDs into the middle current limiting junction was shown to be as high as 29% under one sun illumination for a 10 layer stack QD enhanced triple junction solar cell. QD devices have strong

  2. Process evaluation of enzymatic hydrolysis with filtrate recycle for the production of high concentration sugars.

    Science.gov (United States)

    Xue, Ying; Rusli, Jannov; Chang, Hou-Min; Phillips, Richard; Jameel, Hasan

    2012-02-01

    Process simulation and lab trials were carried out to demonstrate and confirm the efficiency of the concept that recycling hydrolysate at low total solid enzymatic hydrolysis is one of the options to increase the sugar concentration without mixing problems. Higher sugar concentration can reduce the capital cost for fermentation and distillation because of smaller retention volume. Meanwhile, operation cost will also decrease for less operating volume and less energy required for distillation. With the computer simulation, time and efforts can be saved to achieve the steady state of recycling process, which is the scenario for industrial production. This paper, to the best of our knowledge, is the first paper discussing steady-state saccharification with recycling of the filtrate form enzymatic hydrolysis to increase sugar concentration. Recycled enzymes in the filtrate (15-30% of the original enzyme loading) resulted in 5-10% higher carbohydrate conversion compared to the case in which recycled enzymes were denatured. The recycled hydrolysate yielded 10% higher carbohydrate conversion compared to pure sugar simulated hydrolysate at the same enzyme loading, which indicated hydrolysis by-products could boost enzymatic hydrolysis. The high sugar concentration (pure sugar simulated) showed inhibition effect, since about 15% decrease in carbohydrate conversion was observed compared with the case with no sugar added. The overall effect of hydrolysate recycling at WinGEMS simulated steady-state conditions with 5% total solids was increasing the sugar concentration from 35 to 141 g/l, while the carbohydrate conversion was 2% higher for recycling at steady state (87%) compared with no recycling strategy (85%). Ten percent and 15% total solid processes were also evaluated in this study.

  3. Bleaching and enamel surface interactions resulting from the use of highly-concentrated bleaching gels.

    Science.gov (United States)

    Grazioli, Guillermo; Valente, Lisia Lorea; Isolan, Cristina Pereira; Pinheiro, Helena Alves; Duarte, Camila Gonçalves; Münchow, Eliseu Aldrighi

    2018-03-01

    Tooth bleaching is considered a non-invasive treatment, although the use of highly-concentrated products may provoke increased surface roughness and enamel demineralization, as well as postoperative sensitivity. Thus, the aim of this study was to investigate whether hydrogen peroxide (H 2 O 2 ) concentration would affect tooth bleaching effectiveness and the enamel surface properties. Enamel/dentin bovine specimens (6 × 4 mm) were immersed in coffee solution for 7 days and evaluated with a spectrophotometer (Easyshade; baseline), using the CIEL * a * b * color parameters. Hardness was measured using a hardness tester. The specimens were randomly assigned into four groups: one negative control, in which the specimens were not bleached, but they were irradiated with a laser-light source (Whitening Lase II, DMC Equipments); and three groups using distinct H 2 O 2 concentration, namely LP15% (15% Lase Peroxide Lite), LP25% (25% Lase Peroxide Sensy), and LP35% (35% Lase Peroxide Sensy), all products from DMC. The bleached specimens were also irradiated with the laser-light source. After bleaching, all specimens were evaluated using scanning electron microscopy (SEM). pH kinetics and rate was monitored during bleaching. The data were analyzed using ANOVA and Tukey's test (p bleaching gels produced similar color change (p > 0.05). Concerning hardness, only the LP25% and LP35% significantly reduced hardness after bleaching; also, there was a progressive tendency for a greater percentage reduction in hardness with increased H 2 O 2 concentration of the gel (R 2  = 0.9973, p bleaching effectiveness, and may increase the possibility for alteration of enamel hardness, surface morphology, and acidity of the medium. When using H 2 O 2 -based bleaching agents, dental practitioners should choose for less concentrated gels, e.g., around the 15% level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Diagnostic of N2(A) concentration in high velocity nitrogen afterglow at atmospheric pressure

    Science.gov (United States)

    Pointu, Anne-Marie; Mintusov, Evgeny

    2009-10-01

    An optical emission diagnostic was used to measure N2(A) concentration in a high velocity (1000 cm/s) N2 flowing afterglow of corona discharge at atmospheric pressure, used for biological decontamination. Introducing impurities of NO (measured at different axial distances and for different values of NO injected flow. Moreover, it has been demonstrated that N2(A) creation comes from N+N+N2 atom recombination with a global rate around 2e-33 cm^6/s, a result which agrees with literature, as well as N2(A) loss mechanisms were confirmed to go via quenching with O and N atoms. The order of magnitude of obtained N2(A) concentration, about 1e11 cm-3, coincides with the results of direct measurement (by Vegard-Kaplan band), using a spectrometer of better resolution.

  5. Carbon dioxide as working fluid for medium and high-temperature concentrated solar thermal systems

    Directory of Open Access Journals (Sweden)

    Van Duong

    2014-03-01

    Full Text Available This paper explores the benefits and drawbacks of using carbon dioxide in solar thermal systems at medium and high operating temperatures. For medium temperatures, application of CO2 in non-imaging-optics based compound parabolic concentrators (CPC combined with evacuated-tube collectors is studied. These collectors have been shown to obtain efficiencies higher than 40% operating at around 200℃ without the need of tracking. Validated numerical models of external compound parabolic concentrators (XCPCs are used to simulate their performance using CO2 as working fluid. For higher temperatures, a mathematical model is implemented to analyze the operating performance of a parabolic trough solar collector (PTC using CO2 at temperatures between 100℃ and 600℃.

  6. Phenomenon of energy concentration in high-energy family events of cosmic rays

    CERN Document Server

    Wang He; Dai Zhi Qiang; Xue Liang; Feng Cun Feng; Zhang Xue Yao; Li Jin; Zhang Nai Jian; He Mao; Wang Cheng Rui; Ren Jing Ru; Lu Sui Ling

    2002-01-01

    The phenomenon of energy concentration in high-energy family events of cosmic rays is studied by comparing the results of family events of total visible energies 100-400 TeV observed in the Kanbala emulsion chamber experiment with the Monte Carlo simulation data. The simulation is made by the program CORSIKA in which QGSJET is applied as the hadronic interaction model, and the chemical composition of primary cosmic rays is obtained from the rigidity-cut model and the extrapolation of new results of direct measurements. This shows that the whole distribution tendency of the rate of energy concentration of simulated family events is basically consistent with that of the experiment

  7. Green synthesis of highly concentrated aqueous colloidal solutions of large starch-stabilised silver nanoplatelets.

    Science.gov (United States)

    Cheng, Fei; Betts, Jonathan W; Kelly, Stephen M; Hector, Andrew L

    2015-01-01

    A simple, environmentally friendly and cost-effective method has been developed to prepare a range of aqueous silver colloidal solutions, using ascorbic acid as a reducing agent, water-soluble starch as a combined crystallising, stabilising and solubilising agent, and water as the solvent. The diameter of silver nanoplatelets increases with higher concentrations of AgNO3 and starch. The silver nanoparticles are also more uniform in shape the greater the diameter of the nanoparticles. Colloidal solutions with a very high concentration of large, flat, hexagonal silver nanoplatelets (~230 nm in breadth) have been used to deposit and fix an antibacterial coating of these large starch-stabilised silver nanoplates on commercial cotton fibres, using a simple dip-coating process using water as the solvent, in order to study the dependence of the antibacterial properties of these nanoplatelets on their size. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. NMR and MRI of continuously dissolved hyperpolarized {sup 129}Xe by means of hollow fibers

    Energy Technology Data Exchange (ETDEWEB)

    Amor, Nadia; Kueppers, Markus; Bluemich, Bernhard [ITMC of RWTH Aachen University (Germany); Hamilton, Kathrin; Schmitz-Rode, Thomas; Steinseifer, Ulrich [HIA of RWTH Aachen University (Germany); Appelt, Stephan [Research Center Juelich (Germany)

    2011-07-01

    Various methods of hyperpolarizing (HP) spin systems have been developed during the last years to increase the intrinsically low sensitivity of NMR by several orders of magnitude. Among them is the hyperpolarization of {sup 129}Xe via Spin Exchange Optical Pumping (SEOP). NMR of HP {sup 129}Xe is of great interest because of its good solubility and its very sensitive chemical shift. The main obstacle for many applications is the efficient and continuous dissolution into carrier agents without formation of foams or bubbles. It has been overcome by the so-called ''xenonizer'' setups. They mainly consist of commercially available hollow fiber membranes typically used in clinical oxygenators. A purpose-built xenonizer setup has been developed and analyzed in detail by NMR spectroscopy and MRI for varying fiber materials as well as for different fluids, including bio-relevant fluids such as blood, plasma, and erythrocytes. As a result, the xenonizer technology could be further understood and improved, and new applications of HP {sup 129}Xe for medical NMR were explored.

  9. Quantified pH imaging with hyperpolarized (13) C-bicarbonate.

    Science.gov (United States)

    Scholz, David Johannes; Janich, Martin A; Köllisch, Ulrich; Schulte, Rolf F; Ardenkjaer-Larsen, Jan H; Frank, Annette; Haase, Axel; Schwaiger, Markus; Menzel, Marion I

    2015-06-01

    Because pH plays a crucial role in several diseases, it is desirable to measure pH in vivo noninvasively and in a spatially localized manner. Spatial maps of pH were quantified in vitro, with a focus on method-based errors, and applied in vivo. In vitro and in vivo (13) C mapping were performed for various flip angles for bicarbonate (BiC) and CO2 with spectral-spatial excitation and spiral readout in healthy Lewis rats in five slices. Acute subcutaneous sterile inflammation was induced with Concanavalin A in the right leg of Buffalo rats. pH and proton images were measured 2 h after induction. After optimizing the signal to noise ratio of the hyperpolarized (13) C-bicarbonate, error estimation of the spectral-spatial excited spectrum reveals that the method covers the biologically relevant pH range of 6 to 8 with low pH error (< 0.2). Quantification of pH maps shows negligible impact of the residual bicarbonate signal. pH maps reflect the induction of acute metabolic alkalosis. Inflamed, infected regions exhibit lower pH. Hyperpolarized (13) C-bicarbonate pH mapping was shown to be sensitive in the biologically relevant pH range. The mapping of pH was applied to healthy in vivo organs and interpreted within inflammation and acute metabolic alkalosis models. © 2014 Wiley Periodicals, Inc.

  10. Role of an inward rectifier K+ current and of hyperpolarization in human myoblast fusion

    Science.gov (United States)

    Liu, J-H; Bijlenga, P; Fischer-Lougheed, J; Occhiodoro, T; Kaelin, A; Bader, C R; Bernheim, L

    1998-01-01

    The role of K+ channels and membrane potential in myoblast fusion was evaluated by examining resting membrane potential and timing of expression of K+ currents at three stages of differentiation of human myogenic cells: undifferentiated myoblasts, fusion-competent myoblasts (FCMBs), and freshly formed myotubes. Two K+ currents contribute to a hyperpolarization of myoblasts prior to fusion: IK(NI), a non-inactivating delayed rectifier, and IK(IR), an inward rectifier. IK(NI) density is low in undifferentiated myoblasts, increases in FCMBs and declines in myotubes. On the other hand, IK(IR) is expressed in 28 % of the FCMBs and in all myotubes. IK(IR) is reversibly blocked by Ba2+ or Cs+. Cells expressing IK(IR) have resting membrane potentials of −65 mV. A block by Ba2+ or Cs+ induces a depolarization to a voltage determined by IK(NI) (−32 mV). Cs+ and Ba2+ ions reduce myoblast fusion. It is hypothesized that the IK(IR)-mediated hyperpolarization allows FCMBs to recruit Na+, K+ and T-type Ca2+ channels which are present in these cells and would otherwise be inactivated. FCMBs, rendered thereby capable of firing action potentials, could amplify depolarizing signals and may accelerate fusion. PMID:9705997

  11. Molecular MRI in the Earth's Magnetic Field Using Continuous Hyperpolarization of a Biomolecule in Water.

    Science.gov (United States)

    Rovedo, Philipp; Knecht, Stephan; Bäumlisberger, Tim; Cremer, Anna Lena; Duckett, Simon B; Mewis, Ryan E; Green, Gary G R; Burns, Michael; Rayner, Peter J; Leibfritz, Dieter; Korvink, Jan G; Hennig, Jürgen; Pütz, Gerhard; von Elverfeldt, Dominik; Hövener, Jan-Bernd

    2016-06-30

    In this work, we illustrate a method to continuously hyperpolarize a biomolecule, nicotinamide, in water using parahydrogen and signal amplification by reversible exchange (SABRE). Building on the preparation procedure described recently by Truong et al. [ J. Phys. Chem. B , 2014 , 118 , 13882 - 13889 ], aqueous solutions of nicotinamide and an Ir-IMes catalyst were prepared for low-field NMR and MRI. The (1)H-polarization was continuously renewed and monitored by NMR experiments at 5.9 mT for more than 1000 s. The polarization achieved corresponds to that induced by a 46 T magnet (P = 1.6 × 10(-4)) or an enhancement of 10(4). The polarization persisted, although reduced, if cell culture medium (DPBS with Ca(2+) and Mg(2+)) or human cells (HL-60) were added, but was no longer observable after the addition of human blood. Using a portable MRI unit, fast (1)H-MRI was enabled by cycling the magnetic field between 5 mT and the Earth's field for hyperpolarization and imaging, respectively. A model describing the underlying spin physics was developed that revealed a polarization pattern depending on both contact time and magnetic field. Furthermore, the model predicts an opposite phase of the dihydrogen and substrate signal after one exchange, which is likely to result in the cancelation of some signal at low field.

  12. Observations of high droplet number concentrations in Southern Ocean boundary layer clouds

    Directory of Open Access Journals (Sweden)

    T. Chubb

    2016-01-01

    Full Text Available Cloud physics data collected during the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER Pole-to-Pole Observations (HIPPO campaigns provide a snapshot of unusual wintertime microphysical conditions in the boundary layer over the Southern Ocean. On 29 June 2011, the HIAPER sampled the boundary layer in a region of pre-frontal warm air advection between 58 and 48° S to the south of Tasmania. Cloud droplet number concentrations were consistent with climatological values in the northernmost profiles but were exceptionally high for wintertime in the Southern Ocean at 100–200 cm−3 in the southernmost profiles. Sub-micron (0.06  < D <  1 µm aerosol concentrations for the southern profiles were up to 400 cm−3. Analysis of back trajectories and atmospheric chemistry observations revealed that while conditions in the troposphere were more typical of a clean remote ocean airmass, there was some evidence of continental or anthropogenic influence. However, the hypothesis of long-range transport of continental aerosol fails to explain the magnitude of the aerosol and cloud droplet concentration in the boundary layer. Instead, the gale force surface winds in this case (wind speed at 167 m above sea level was  > 25 m s−1 were most likely responsible for production of sea spray aerosol which influenced the microphysical properties of the boundary layer clouds. The smaller size and higher number concentration of cloud droplets is inferred to increase the albedo of these clouds, and these conditions occur regularly, and are expected to increase in frequency, over windy parts of the Southern Ocean.

  13. The salivary microbiome is altered in the presence of a high salivary glucose concentration.

    Directory of Open Access Journals (Sweden)

    J Max Goodson

    Full Text Available Type II diabetes (T2D has been associated with changes in oral bacterial diversity and frequency. It is not known whether these changes are part of the etiology of T2D, or one of its effects.We measured the glucose concentration, bacterial counts, and relative frequencies of 42 bacterial species in whole saliva samples from 8,173 Kuwaiti adolescents (mean age 10.00 ± 0.67 years using DNA probe analysis. In addition, clinical data related to obesity, dental caries, and gingivitis were collected. Data were compared between adolescents with high salivary glucose (HSG; glucose concentration ≥ 1.0 mg/d, n = 175 and those with low salivary glucose (LSG, glucose concentration < 0.1 mg/dL n = 2,537.HSG was associated with dental caries and gingivitis in the study population. The overall salivary bacterial load in saliva decreased with increasing salivary glucose concentration. Under HSG conditions, the bacterial count for 35 (83% of 42 species was significantly reduced, and relative bacterial frequencies in 27 species (64% were altered, as compared with LSG conditions. These alterations were stronger predictors of high salivary glucose than measures of oral disease, obesity, sleep or fitness.HSG was associated with a reduction in overall bacterial load and alterations to many relative bacterial frequencies in saliva when compared with LSG in samples from adolescents. We propose that hyperglycemia due to obesity and/or T2D results in HSG and subsequent acidification of the oral environment, leading to a generalized perturbation in the oral microbiome. This suggests a basis for the observation that hyperglycemia is associated with an increased risk of dental erosion, dental caries, and gingivitis. We conclude that HSG in adolescents may be predicted from salivary microbial diversity or frequency, and that the changes in the oral microbial composition seen in adolescents with developing metabolic disease may the consequence of hyperglycemia.

  14. Root based responses account for Psidium guajava survival at high nickel concentration.

    Science.gov (United States)

    Bazihizina, Nadia; Redwan, Mirvat; Taiti, Cosimo; Giordano, Cristiana; Monetti, Emanuela; Masi, Elisa; Azzarello, Elisa; Mancuso, Stefano

    2015-02-01

    The presence of Psidium guajava in polluted environments has been reported in recent studies, suggesting that this species has a high tolerance to the metal stress. The present study aims at a physiological characterization of P. guajava response to high nickel (Ni) concentrations in the root-zone. Three hydroponic experiments were carried out to characterize the effects of toxic Ni concentrations on morphological and physiological parameters of P. guajava, focusing on Ni-induced damages at the root-level and root ion fluxes. With up to 300μM NiSO4 in the root-zone, plant growth was similar to that in control plants, whereas at concentrations higher than 1000μM NiSO4 there was a progressive decline in plant growth and leaf gas exchange parameters; this occurred despite, at all considered concentrations, plants limited Ni(2+) translocation to the shoot, therefore avoiding shoot Ni(2+) toxicity symptoms. Maintenance of plant growth with 300μM Ni(2+) was associated with the ability to retain K(+) in the roots meanwhile 1000 and 3000μM NiSO4 led to substantial K(+) losses. In this study, root responses mirror all plant performances suggesting a direct link between root functionality and Ni(2+) tolerance mechanisms and plant survival. Considering that Ni was mainly accumulated in the root system, the potential use of P. guajava for Ni(2+) phytoextraction in metal-polluted soils is limited; nevertheless, the observed physiological changes indicate a good Ni(2+) tolerance up to 300μM NiSO4 suggesting a potential role for the phytostabilization of polluted soils. Copyright © 2014 Elsevier GmbH. All rights reserved.

  15. High Ice Water Concentrations in the 19 August 2015 Coastal Mesoconvective System

    Science.gov (United States)

    Proctor, Fred H.; Harrah, Steven; Switzer, George F.; Strickland, Justin K.; Hunt, Patricia J.

    2017-01-01

    During August 2015, NASA's DC-8 research aircraft was flown into High Ice Water Content (HIWC) events as part of a three-week campaign to collect airborne radar data and to obtain measurements from microphysical probes. Goals for this flight campaign included improved characterization of HIWC events, especially from an airborne radar perspective. This paper focuses on one of the flight days, in which a coastal mesoscale convective system (MCS) was investigated for HIWC conditions. The system appears to have been maintained by bands of convection flowing in from the Gulf of Mexico. These convective bands were capped by a large cloud canopy, which masks the underlying structure if viewed from an infrared sensing satellite. The DC-8 was equipped with an IsoKinetic Probe that measured ice concentrations of up to 2.3 g m(exp -3) within the cloud canopy of this system. Sustained measurements of ice crystals with concentrations exceeding 1 g m(exp -3) were encountered for up to ten minutes of flight time. Airborne Radar reflectivity factors were found to be weak within these regions of high ice water concentrations, suggesting that Radar detection of HIWC would be a challenging endeavor. This case is then investigated using a three-dimensional numerical cloud model. Profiles of ice water concentrations and radar reflectivity factor demonstrate similar magnitudes and scales between the flight measurements and model simulation. Also discussed are recent modifications to the numerical model's ice-microphysics that are based on measurements during the flight campaign. The numerical model and its updated ice-microphysics are further validated with a simulation of a well-known case of a supercell hailstorm measured during the Cooperative Convective Precipitation Experiment. Differences in HIWC between the continental supercell and the coastal MCS are discussed.

  16. Use of high concentrations of carbon dioxide for stunning rabbits reared for meat production

    Directory of Open Access Journals (Sweden)

    A. Dalmau

    2016-03-01

    Full Text Available Abstract: An investigation was performed to determine whether high concentrations of carbon dioxide (CO2 at 70-98% in atmospheric air are a suitable alternative for stunning rabbits compared to conventional approaches such as electronarcosis. Aversion to the gas and efficacy in causing prolonged unconsciousness and death were studied in a total of 480 rabbits by means of behavioural parameters, physiological indicators (presence of rhythmic breathing and corneal reflex and electroencephalography (EEG, brain function. The use of any of the 4 studied concentrations of the gas caused more nasal discomfort and vocalisations than the use of atmospheric air (P<0.001. EEG activity confirmed that loss of posture is a good indicator of the onset of unconsciousness in rabbits exposed to CO2, occurring earlier (P<0.05 at 90 and 98% than at 70 and 80%. Rabbits showed signs of aversion for 15 s before the onset of unconsciousness, which occurred around 30 s after the beginning of the exposure to the gas, similar to species such as swine in which high concentrations of CO2 are also used for stunning. CO2 at 80 to 98% is suggested as a reasonable concentration range to induce a long state of unconsciousness and death in rabbits, while 70% CO2 is not recommended because it requires too long duration of exposure (more than 360 s to ensure effectiveness. Despite the advantages in terms of pre-stun handling and irreversibility, CO2 is not free of animal welfare concerns. In consequence, a debate is necessary to ascertain if CO2 can be considered a suitable alternative to stun rabbits, considering the advantages and drawbacks cited, quantified in the present study as 15 s of aversion (nasal discomfort and vocalisations before losing posture.

  17. Factors affecting biotic mercury concentrations and biomagnification through lake food webs in the Canadian high Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Lescord, Gretchen L., E-mail: glescord@gmail.com [University of New Brunswick/Canadian Rivers Institute, 100 Tucker Park Rd, Saint John, NB E2L 4A6 (Canada); Kidd, Karen A. [University of New Brunswick/Canadian Rivers Institute, 100 Tucker Park Rd, Saint John, NB E2L 4A6 (Canada); Kirk, Jane L. [Environment Canada, Aquatic Contaminants Research Division, 867 Lakeshore Rd, Burlington, ON L7S 1A1 (Canada); O' Driscoll, Nelson J. [Acadia University, 15 University Ave, Wolfville, NS B4P 2R6 (Canada); Wang, Xiaowa; Muir, Derek C.G. [Environment Canada, Aquatic Contaminants Research Division, 867 Lakeshore Rd, Burlington, ON L7S 1A1 (Canada)

    2015-03-15

    In temperate regions of Canada, mercury (Hg) concentrations in biota and the magnitude of Hg biomagnification through food webs vary between neighboring lakes and are related to water chemistry variables and physical lake features. However, few studies have examined factors affecting the variable Hg concentrations in landlocked Arctic char (Salvelinus alpinus) or the biomagnification of Hg through their food webs. We estimated the food web structure of six high Arctic lakes near Resolute Bay, Nunavut, Canada, using stable carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) isotopes and measured Hg (total Hg (THg) in char, the only fish species, and methylmercury (MeHg) in chironomids and zooplankton) concentrations in biota collected in 2010 and 2011. Across lakes, δ{sup 13}C showed that benthic carbon (chironomids) was the dominant food source for char. Regression models of log Hg versus δ{sup 15}N (of char and benthic invertebrates) showed positive and significant slopes, indicting Hg biomagnification in all lakes, and higher slopes in some lakes than others. However, no principal components (PC) generated using all water chemistry data and physical characteristics of the lakes predicted the different slopes. The PC dominated by aqueous ions was a negative predictor of MeHg concentrations in chironomids, suggesting that water chemistry affects Hg bioavailability and MeHg concentrations in these lower-trophic-level organisms. Furthermore, regression intercepts were predicted by the PCs dominated by catchment area, aqueous ions, and MeHg. Weaker relationships were also found between THg in small char or MeHg in pelagic invertebrates and the PCs dominated by catchment area, and aqueous nitrate and MeHg. Results from these high Arctic lakes suggest that Hg biomagnification differs between systems and that their physical and chemical characteristics affect Hg concentrations in lower-trophic-level biota. - Highlights: • Mercury (Hg) in Arctic char and invertebrates

  18. Reactive Transport Modeling Investigation of High Dissolved Sulfide Concentrations in Sedimentary Basin Rocks

    Science.gov (United States)

    Xie, M.; Mayer, U. K.; MacQuarrie, K. T. B.

    2017-12-01

    Water with total dissolved sulfide in excess of 1 mmol L-1is widely found in groundwater at intermediate depths in sedimentary basins, including regions of the Michigan basin in southeastern Ontario, Canada. Conversely, at deeper and shallower depths, relatively low total dissolved sulfide concentrations have been reported. The mechanisms responsible for the occurrence of these brackish sulfide-containing waters are not fully understood. Anaerobic microbial sulfate reduction is a common process resulting in the formation of high sulfide concentrations. Sulfate reduction rates depend on many factors including the concentration of sulfate, the abundance of organic substances, redox conditions, temperature, salinity and the species of sulfate reducing bacteria (SRB). A sedimentary basin-specific conceptual model considering the effect of salinity on the rate of sulfate reduction was developed and implemented in the reactive transport model MIN3P-THCm. Generic 2D basin-scale simulations were undertaken to provide a potential explanation for the dissolved sulfide distribution observed in the Michigan basin. The model is 440 km in the horizontal dimension and 4 km in depth, and contains fourteen sedimentary rock units including shales, sandstones, limestones, dolostone and evaporites. The main processes considered are non-isothermal density dependent flow, kinetically-controlled mineral dissolution/precipitation and its feedback on hydraulic properties, cation exchange, redox reactions, biogenic sulfate reduction, and hydromechanical coupling due to glaciation-deglaciation events. Two scenarios were investigated focusing on conditions during an interglacial period and the transient evolution during a glaciation-deglaciation cycle. Inter-glaciation simulations illustrate that the presence of high salinity brines strongly suppress biogenic sulfate reduction. The transient simulations show that glaciation-deglaciation cycles can have an impact on the maximum depth of

  19. Solution Behavior and Activity of a Halophilic Esterase under High Salt Concentration

    Science.gov (United States)

    Rao, Lang; Zhao, Xiubo; Pan, Fang; Li, Yin; Xue, Yanfen; Ma, Yanhe; Lu, Jian R.

    2009-01-01

    Background Halophiles are extremophiles that thrive in environments with very high concentrations of salt. Although the salt reliance and physiology of these extremophiles have been widely investigated, the molecular working mechanisms of their enzymes under salty conditions have been little explored. Methodology/Principal Findings A halophilic esterolytic enzyme LipC derived from archeaon Haloarcula marismortui was overexpressed from Escherichia coli BL21. The purified enzyme showed a range of hydrolytic activity towards the substrates of p-nitrophenyl esters with different alkyl chains (n = 2−16), with the highest activity being observed for p-nitrophenyl acetate, consistent with the basic character of an esterase. The optimal esterase activities were found to be at pH 9.5 and [NaCl] = 3.4 M or [KCl] = 3.0 M and at around 45°C. Interestingly, the hydrolysis activity showed a clear reversibility against changes in salt concentration. At the ambient temperature of 22°C, enzyme systems working under the optimal salt concentrations were very stable against time. Increase in temperature increased the activity but reduced its stability. Circular dichroism (CD), dynamic light scattering (DLS) and small angle neutron scattering (SANS) were deployed to determine the physical states of LipC in solution. As the salt concentration increased, DLS revealed substantial increase in aggregate sizes, but CD measurements revealed the maximal retention of the α-helical structure at the salt concentration matching the optimal activity. These observations were supported by SANS analysis that revealed the highest proportion of unimers and dimers around the optimal salt concentration, although the coexistent larger aggregates showed a trend of increasing size with salt concentration, consistent with the DLS data. Conclusions/Significance The solution α-helical structure and activity relation also matched the highest proportion of enzyme unimers and dimers. Given that

  20. Soil and Water Assessment Tool model predictions of annual maximum pesticide concentrations in high vulnerability watersheds.

    Science.gov (United States)

    Winchell, Michael F; Peranginangin, Natalia; Srinivasan, Raghavan; Chen, Wenlin

    2018-05-01

    Recent national regulatory assessments of potential pesticide exposure of threatened and endangered species in aquatic habitats have led to increased need for watershed-scale predictions of pesticide concentrations in flowing water bodies. This study was conducted to assess the ability of the uncalibrated Soil and Water Assessment Tool (SWAT) to predict annual maximum pesticide concentrations in the flowing water bodies of highly vulnerable small- to medium-sized watersheds. The SWAT was applied to 27 watersheds, largely within the midwest corn belt of the United States, ranging from 20 to 386 km 2 , and evaluated using consistent input data sets and an uncalibrated parameterization approach. The watersheds were selected from the Atrazine Ecological Exposure Monitoring Program and the Heidelberg Tributary Loading Program, both of which contain high temporal resolution atrazine sampling data from watersheds with exceptionally high vulnerability to atrazine exposure. The model performance was assessed based upon predictions of annual maximum atrazine concentrations in 1-d and 60-d durations, predictions critical in pesticide-threatened and endangered species risk assessments when evaluating potential acute and chronic exposure to aquatic organisms. The simulation results showed that for nearly half of the watersheds simulated, the uncalibrated SWAT model was able to predict annual maximum pesticide concentrations within a narrow range of uncertainty resulting from atrazine application timing patterns. An uncalibrated model's predictive performance is essential for the assessment of pesticide exposure in flowing water bodies, the majority of which have insufficient monitoring data for direct calibration, even in data-rich countries. In situations in which SWAT over- or underpredicted the annual maximum concentrations, the magnitude of the over- or underprediction was commonly less than a factor of 2, indicating that the model and uncalibrated parameterization

  1. Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

    Science.gov (United States)

    Voichick, Nicholas; Topping, David; Griffiths, Ronald

    2018-01-01

    Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator–prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples

  2. Preparation of a highly concentrated, completely monomeric, active sarcoplasmic reticulum Ca2+-ATPase.

    Science.gov (United States)

    Lüdi, H; Hasselbach, W

    1985-11-21

    Sarcoplasmic reticulum vesicles from fast skeletal muscle were partially delipidated with sodium cholate at high ionic strength and sedimented in a discontinuous sucrose gradient. Phospholipid content was reduced from 0.777 mumol/mg protein to 0.242 mumol/mg protein. As judged from gel electrophoresis and high pressure liquid gel chromatography, accessory proteins were removed during centrifugation and the Ca2+-ATPase was obtained in an almost pure form. Addition of myristoylglycerophosphocholine (1 mg/mg protein) reactivates ATPase and dinitrophenylphosphatase activity to the same degree obtained with native vesicles. Using the analytical ultracentrifuge it could be demonstrated that the reactivated Ca2+-ATPase was present exclusively in a monomeric state. These results were obtained at high and low ionic strength and up to a protein concentration of 10 mg/ml. Therefore this preparation should be very useful to investigate differences between oligomeric and monomeric Ca2+-ATPase.

  3. Large-area, high-intensity PV arrays for systems using dish concentrating optics

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.S.; Duda, A.; Zweibel, K.; Coutts, T.J. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    In this paper, the authors report on efforts to fabricate monolithic interconnected modules (MIMs) using III-V semiconductors with bandgaps appropriate for the terrestrial solar spectrum. The small size of the component cells comprising the MIM allows for operation at extremely high flux densities and relaxes the requirement for a small spot size to be generated by the optics. This makes possible a PV option for the large dish concentrator systems that have been developed by the solar thermal community for use with Stirling engines. Additionally, the highly effective back-surface reflector integrated into the MIM design is an effective tool for thermal management of the array. Development of this technology would radically alter the projections for PV manufacturing capacity because of the potential for extremely high power generation per unit area of semiconductor material.

  4. Corrosion mechanism of 13Cr stainless steel in completion fluid of high temperature and high concentration bromine salt

    International Nuclear Information System (INIS)

    Liu, Yan; Xu, Lining; Lu, Minxu; Meng, Yao; Zhu, Jinyang; Zhang, Lei

    2014-01-01

    Highlights: • The corrosion behavior of 13Cr steel exposed to bromine salt completion fluid containing high concentration bromine ions was investigated. • There are passive circles around pits on the 13Cr steel surface after 7 d of exposure. • Macroscopic galvanic corrosion formed between the passive halo and the pit. • The mechanism of pitting corrosion on 13Cr stainless steel exposed to heavy bromine brine was established. - Abstract: A series of corrosion tests of 13Cr stainless steel were conducted in a simulated completion fluid environment of high temperature and high concentration bromine salt. Corrosion behavior of specimens and the component of corrosion products were investigated by means of scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). The results indicate that 13Cr steel suffers from severe local corrosion and there is always a passive halo around every pit. The formation mechanism of the passive halo is established. OH − ligand generates and adsorbs in a certain scale because of abundant OH − on the surface around the pits. Passive film forms around each pit, which leads to the occurrence of passivation in a certain region. Finally, the dissimilarities in properties and morphologies of regions, namely the pit and its corresponding passive halo, can result in different corrosion sensitivities and may promote the formation of macroscopic galvanic pairs

  5. Characteristics and treatment mechanism of mine water with high concentration of iron and manganese

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.; Yang, J.; He, X.; Yang, J.; Tian, T. [Hebei University of Engineering, Handan (China)

    2006-12-15

    The characteristics and treatment of mine water with high concentration or iron and manganese were studied with mine water produced in Jiukuang and Siwan belonging to Hebi Coal Industry Group Co., Ltd. Analysis shows that the mine water is abundant in dissolved oxygen and has high TDS and high turbidity so the mine water does not need aeration. The effect of removal of iron and manganese by coagulation-sedimentation and the influence of filter material and influent water flow rate on effluent quality were investigated. It is shown that the removal rate of iron can reach 90% while removal of manganese can only reach about 20%. The concentration of iron and manganese in the effluent is lower than 0.1 mg/L with filter material of manganese sand which was immersed in KMnO{sub 4} solution at a filtration rate of 7 - 9 m/h. The results show that the layer of activated compound substance membrane formed on the surface of the manganese sand plays an important role in the removal of manganese. 7 refs., 2 figs., 3 tabs.

  6. Preparation of ultra-light magnetic nanocomposites using highly concentrated emulsions

    International Nuclear Information System (INIS)

    Ghosh, Goutam; Vilchez, Alejandro; Esquena, Jordi; Solans, Conxita; Rodriguez-Abreu, Carlos

    2011-01-01

    Highlights: → Polystyrene-divinylbenzene-iron oxide nanocomposites. → Porous magnetic nanocomposites from highly concentrated emulsions. → Ultralight materials with relatively high magnetic moment. - Abstract: Hybrid inorganic-organic ultra-light magnetic solid foams with iron oxide nanoparticles embedded in a divinylbenzene-polystyrene matrix were prepared using a highly concentrated emulsion polymerization method. Iron oxide nanoparticles with diameters of 3 and 10 nm were synthesized using two different methods. For comparison purposes, nanocomposites with magnetite nanoparticles dispersed in a non-porous polymeric matrix obtained by bulk polymerization were also investigated. Materials were characterized using several techniques such as dynamic light scattering (DLS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and magnetization measurements. SEM and TEM images showed that solid foams are made of well-defined macro pores with nanoparticles embedded in the walls. The density of the solid foams was ca. 50-70 kg m -3 , which is about 20 times lighter than the non-porous monoliths. The magnetic measurements show that both nanocomposites are superparamagnetic, and that there are differences regarding the interparticle interactions depending on matrix porosity. The synthesized materials may find applications in adsorbents, tissue reparation, enzyme supports, microreactors, or in water decontamination.

  7. Preparation of ultra-light magnetic nanocomposites using highly concentrated emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Goutam; Vilchez, Alejandro; Esquena, Jordi; Solans, Conxita [Instituto de Quimica Avanzada de Cataluna, Consejo Superior de Investigaciones Cientificas (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Rodriguez-Abreu, Carlos, E-mail: carlos.rodriguez@inl.int [Instituto de Quimica Avanzada de Cataluna, Consejo Superior de Investigaciones Cientificas (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); International Iberian Nanotechnology Laboratory (INL), Av. Mestre Jose Veiga, 4715-330 Braga (Portugal)

    2011-10-17

    Highlights: {yields} Polystyrene-divinylbenzene-iron oxide nanocomposites. {yields} Porous magnetic nanocomposites from highly concentrated emulsions. {yields} Ultralight materials with relatively high magnetic moment. - Abstract: Hybrid inorganic-organic ultra-light magnetic solid foams with iron oxide nanoparticles embedded in a divinylbenzene-polystyrene matrix were prepared using a highly concentrated emulsion polymerization method. Iron oxide nanoparticles with diameters of 3 and 10 nm were synthesized using two different methods. For comparison purposes, nanocomposites with magnetite nanoparticles dispersed in a non-porous polymeric matrix obtained by bulk polymerization were also investigated. Materials were characterized using several techniques such as dynamic light scattering (DLS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and magnetization measurements. SEM and TEM images showed that solid foams are made of well-defined macro pores with nanoparticles embedded in the walls. The density of the solid foams was ca. 50-70 kg m{sup -3}, which is about 20 times lighter than the non-porous monoliths. The magnetic measurements show that both nanocomposites are superparamagnetic, and that there are differences regarding the interparticle interactions depending on matrix porosity. The synthesized materials may find applications in adsorbents, tissue reparation, enzyme supports, microreactors, or in water decontamination.

  8. Regional and local meteorology influences high-resolution tropospheric ozone concentration in the Los Angeles Basin

    Science.gov (United States)

    Koutzoukis, S.; Jenerette, D.; Chandler, M.; Wang, J.; Ge, C.; Ripplinger, J.

    2017-12-01

    Urban air quality and climate directly affect resident health. The Los Angeles (LA) Basin is a highly populated metropolitan area, with widespread point sources of ozone (O3) precursors (NOx , Volatile Organic Compounds, CO) from fossil fuel combustion. The LA basin exists on a coast-to-mountain gradient, with increasing temperatures towards the Transverse Ranges, which rise to 1700m. Frequently not compliant with 8-hour O3 standards, the LA and South Coast Air Basins are designated as severe and extreme non-attainment areas. Summer weather in the LA basin is characterized by a persistent high pressure system, creating an inversion that traps air pollutants, including O3 precursors, coupled with physical geography that blocks prevailing upper atmosphere air flow. These interactions make neighborhood-level O3 levels more variable than common regional models. Over the summer of 2017, we investigated the importance of local meteorology, wind patterns and air temperature, in transporting and mixing ozone precursors from point sources along the coast-to-mountain gradient. We deployed a network of six EPA federal equivalent method ozone and meteorological sensors in three campaigns in the LA basin along the coast-to-mountain transect. Each campaign, we collaborated with citizen scientists to deploy three sensor stations in two, 4 km2 quadrats, for a total of six high-resolution 4 km2 pixels. O3 concentrations vary greatly along the transect. At the coastal sites, daily O3 ranges from 0ppm to 60ppm and the range increases at the inland sites, to 100ppm. At all sites, there was a positive relationship between wind speed, air temperature, and O3 concentration, with increasing correlation inland. The Pearson correlation coefficient between wind speed and O3 concentration doubles from the coast to inland, and triples between air temperature and O3. The site-specific relationships between O3 and wind direction and temperature vary, suggesting neighborhood-effects from local

  9. Effects of meals rich in either monounsaturated or saturated fat on lipid concentrations and on insulin secretion and action in subjects with high fasting triglyceride concentrations.

    Science.gov (United States)

    Lopez, Sergio; Bermudez, Beatriz; Ortega, Almudena; Varela, Lourdes M; Pacheco, Yolanda M; Villar, Jose; Abia, Rocio; Muriana, Francisco J G

    2011-03-01

    The nature of dietary fats and fasting concentrations of triglycerides affect postprandial hypertriglyceridemia and glucose homeostasis. The objectives were to examine the effects of meals enriched in monounsaturated fatty acids (MUFAs) or saturated fatty acids (SFAs) on postprandial lipid, glucose, and insulin concentrations and to examine the extent of β cell function and insulin sensitivity in subjects with high fasting triglyceride concentrations. Fourteen men with fasting hypertriglyceridemia and normal glucose tolerance were given meals (≈10 kcal/kg body weight) containing MUFAs, SFAs, or no fat. Blood samples were collected at baseline and hourly over 8 h for analysis. The high-fat meals significantly increased postprandial concentrations of triglycerides, nonesterified fatty acids, and insulin and postprandial indexes of β cell function. However, postprandial indexes of insulin sensitivity decreased significantly. These effects were significantly attenuated with MUFAs relative to SFAs. MUFAs postprandially buffered β cell hyperactivity and insulin intolerance relative to SFAs in subjects with high fasting triglyceride concentrations. These data suggest that, in contrast with SFAs, MUFA-based strategies may provide cardiovascular benefits to persons at risk by limiting lipid and insulin excursions and may contribute to optimal glycemic control after meal challenges.

  10. Effect of concentrate feeder design on performance, eating and animal behavior, welfare, ruminal health, and carcass quality in Holstein bulls fed high-concentrate diets.

    Science.gov (United States)

    Verdú, M; Bach, A; Devant, M

    2015-06-01

    A total of 240 Holstein bulls (121 ± 2.0 kg initial BW; 99 ± 1.0 d of age), from 2 consecutive fattening cycles, were randomly allocated in 1 of 6 pens and assigned to 1 of the 3 treatments consisting of different concentrate feeder designs: a control feeder with 4 feeding spaces (CF), a feeder with less concentrate capacity (CFL), and a single-space feeder with lateral protections (SF). Each pen had a straw feeder and a drinker. All animals were fed a high-concentrate diet for ad libitum intake. Concentrate consumption was recorded daily using a computerized feeder, straw consumption was recorded weekly, and BW was recorded every 14 d. Animal behavior was registered on d 1, 3, 5, 8, and 14 and every 28 d by scan sampling. Eating behavior at concentrate feeders was filmed on d 12, 125, and 206. On d 7, 120, and 204, samples of rumen contents were collected for measurement of pH and VFA and blood samples were obtained to analyze NEFA, haptoglobin, glucose, and insulin. Animals were slaughtered after 223 d, and HCW and lesions of the rumen wall and liver were recorded. The accumulative concentrate consumption per animal tended (P = 0.09) to be greater with CF than with CFL and SF. Also, CV of concentrate consumption was greater (P carcass data. Also, no differences among treatments in rumen wall evaluation and liver abscesses were observed. At 7 and 204 d of study, SF bulls had greater (P animal welfare in Holstein bulls fed high-concentrate diets. However, at the beginning, there was evidence that animals fed using SF had problems with adaptation.

  11. Study on automatic control of high uranium concentration solvent extraction with pulse sieve-plate column

    International Nuclear Information System (INIS)

    You Wenzhi; Xing Guangxuan; Long Maoxiong; Zhang Jianmin; Zhou Qin; Chen Fuping; Ye Lingfeng

    1998-01-01

    The author mainly described the working condition of the automatic control system of high uranium concentration solvent extraction with pulse sieve-plate column on a large scale test. The use of the automatic instrument and meter, automatic control circuit, and the best feedback control point of the solvent extraction processing with pulse sieve-plate column are discussed in detail. The writers point out the success of this experiment on automation, also present some questions that should be cared for the automatic control, instruments and meters in production in the future

  12. Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective.

    Science.gov (United States)

    Santos, Bruna Marques Dos; Balbuena, Tiago Santana

    2017-01-06

    Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO 2 concentrations. Growth under a high concentration of CO 2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO 2 . Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO 2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO 2 . Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO 2 -enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates. The sample enrichment strategy and data analysis used here enabled the identification of all enzymes and most protein isoforms involved in the Calvin-Benson-Bessham cycle in Eucalyptus urophylla. Upon growth in CO 2 -enriched chambers, Eucalyptus urophylla plantlets responded by reducing the vascular bundle area and stomatal aperture size and by increasing the abundance of six of the eleven core enzymes involved in carbon fixation. Our proteome approach provides an estimate on how a commercially important C3-type plant would respond to an increase in CO 2 concentrations. Additionally, confirmation at the protein level of the predicted genes involved in

  13. Composition of highly concentrated silicate electrolytes and ultrasound influencing the plasma electrolytic oxidation of magnesium

    Science.gov (United States)

    Simchen, F.; Rymer, L.-M.; Sieber, M.; Lampke, T.

    2017-03-01

    Magnesium and its alloys are increasingly in use as lightweight construction materials. However, their inappropriate corrosion and wear resistance often prevent their direct practical use. The plasma electrolytic oxidation (PEO) is a promising, environmentally friendly method to improve the surface characteristics of magnesium materials by the formation of oxide coatings. These PEO layers contain components of the applied electrolyte and can be shifted in their composition by increasing the concentration of the electrolyte constituents. Therefore, in contrast to the use of conventional low concentrated electrolytes, the process results in more stable protective coatings, in which electrolyte species are the dominating constitutes. In the present work, the influence of the composition of highly concentrated alkaline silicate electrolytes with additives of phosphate and glycerol on the quality of PEO layers on the magnesium alloy AZ31 was examined. The effect of ultrasound coupled into the electrolyte bath was also considered. The process was monitored by recording the electrical process variables with a transient recorder and by observation of the discharge phenomena on the sample surface with a camera. The study was conducted on the basis of a design of experiments. The effects of the process parameter variation are considered with regard to the coatings thickness, hardness and corrosion resistance. Information about the statistical significance of the effects of the parameters on the considered properties is obtained by an analysis of variance (ANOVA).

  14. High plasma concentrations of asymmetric dimethylarginine inhibit ischemic cardioprotection in hypercholesterolemic rats

    International Nuclear Information System (INIS)

    Landim, M.B.P.; Dourado, P.M.M.; Casella-Filho, A.; Chagas, A.C.P.; Luz, P.L. da

    2013-01-01

    A low concentration of nitric oxide associated with a high concentration of asymmetric dimethylarginine (ADMA) can explain the lack of ischemic cardioprotection observed in the presence of hypercholesterolemia. The objective of the present study was to evaluate the effect of hypercholesterolemia on ischemic pre- and postconditioning and its correlation with plasma concentrations of ADMA. Male Wistar rats (6-8 weeks old) fed a 2% cholesterol diet (n = 21) for 8 weeks were compared to controls (n = 25) and were subjected to experimental myocardial infarction and reperfusion, with ischemic pre- and postconditioning. Total cholesterol and ADMA were measured in plasma before the experimental infarct and the infarct area was quantified. Weight, total cholesterol and plasma ADMA (means ± SE; 1.20 ± 0.06, 1.27 ± 0.08 and 1.20 ± 0.08 vs 0.97 ± 0.04, 0.93 ± 0.05 and 0.97 ± 0.04 µM) were higher in animals on the hypercholesterolemic diet than in controls, respectively. Cardioprotection did not reduce infarct size in the hypercholesterolemic animals (pre: 13.55% and post: 8% compared to 7.95% observed in the group subjected only to ischemia and reperfusion), whereas infarct size was reduced in the animals on a normocholesterolemic diet (pre: 8.25% and post: 6.10% compared to 12.31%). Hypercholesterolemia elevated ADMA and eliminated the cardioprotective effects of ischemic pre- and postconditioning in rats

  15. High plasma concentrations of asymmetric dimethylarginine inhibit ischemic cardioprotection in hypercholesterolemic rats

    Energy Technology Data Exchange (ETDEWEB)

    Landim, M.B.P.; Dourado, P.M.M.; Casella-Filho, A.; Chagas, A.C.P.; Luz, P.L. da [Unidade de Aterosclerose, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

    2013-05-10

    A low concentration of nitric oxide associated with a high concentration of asymmetric dimethylarginine (ADMA) can explain the lack of ischemic cardioprotection observed in the presence of hypercholesterolemia. The objective of the present study was to evaluate the effect of hypercholesterolemia on ischemic pre- and postconditioning and its correlation with plasma concentrations of ADMA. Male Wistar rats (6-8 weeks old) fed a 2% cholesterol diet (n = 21) for 8 weeks were compared to controls (n = 25) and were subjected to experimental myocardial infarction and reperfusion, with ischemic pre- and postconditioning. Total cholesterol and ADMA were measured in plasma before the experimental infarct and the infarct area was quantified. Weight, total cholesterol and plasma ADMA (means ± SE; 1.20 ± 0.06, 1.27 ± 0.08 and 1.20 ± 0.08 vs 0.97 ± 0.04, 0.93 ± 0.05 and 0.97 ± 0.04 µM) were higher in animals on the hypercholesterolemic diet than in controls, respectively. Cardioprotection did not reduce infarct size in the hypercholesterolemic animals (pre: 13.55% and post: 8% compared to 7.95% observed in the group subjected only to ischemia and reperfusion), whereas infarct size was reduced in the animals on a normocholesterolemic diet (pre: 8.25% and post: 6.10% compared to 12.31%). Hypercholesterolemia elevated ADMA and eliminated the cardioprotective effects of ischemic pre- and postconditioning in rats.

  16. Compact high-sensitivity potentiometer for detection of low ion concentrations in liquids

    Science.gov (United States)

    Balevicius, Z.; Lescinskas, R.; Celiesiute, R.; Stirke, A.; Balevicius, S.; Kersulis, S.; Bleizgys, V.; Maciuleviciene, R.; Ramanavicius, A.; Zurauskiene, N.

    2018-04-01

    The compact potentiometer, based on an electronic circuit protected from electrostatic and electromagnetic interference, was developed for the measurement of low ion concentrations in liquids. The electronic circuit of the potentiometer, consisting of analogous and digital parts, enables the measurement of fA currents. This makes it possible to perform reliable measurements of ion concentrations in liquids that are as small as 10-8-10-7M. The instrument was tested using electrodes that were selective for tetraphenylphosphonium (TPP+) ions. It was demonstrated that the characteristic response time of the potentiometer electronic circuit to changes in the concentration of these ions in a liquid was in the order of 10 s. An investigation of TPP+ absorption by baker yeast has shown that this device can be successfully used for long term (several hours) measurements with zero signal drift, which was about 1 μV/s. Finally, due to the small dimensions of the electronic circuit (7.5 × 2 × 1.5 cm), this potentiometer can be easily installed at a large apparatus in the laboratory condition (≈25 °C), such as high pulsed electrical generators of magnetic fields that are used in electroporation studies of biological cells.

  17. Effect of thymol and carvacrol on nutrient digestibility in rams fed high or low concentrate diets.

    Science.gov (United States)

    Zamiri, M J; Azizabadi, E; Momeni, Z; Rezvani, M R; Atashi, H; Akhlaghi, A

    2015-01-01

    Published data on the effects of essential oils (EO) on in vivo nutrient digestibility in sheep are contradictory. In 2 experiments, the effect of thymol and carvacrol on nutrient digestibility was studied in sheep fed with high (70%) or low (52%) concentrate diets, using incomplete Latin Square designs. The essential oils were mixed with the concentrate portion of the diet at the rate of 0.0, 0.3, or 0.6 g per kg dry matter (DM) diet. Supplementation of thymol had no significant effect on digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and acid detergent fiber (ADF). The main effect of thymol on neutral detergent fiber (NDF) and ether extract (EE) digestibility and on nitrogen balance (NB) was significant (Pdigestibility. The main effect of carvacrol on ruminal ammonia levels and NB was significant, but within each level of dietary concentrate no significant differences were observed in ammonia levels and NB. Inclusion of 0.3 g/kg diet DM of carvacrol or thyme was more effective than 0.6 g/kg diet DM in terms of NB but neither dose affected nutrient digestibility. Future research should determine the long-term effects of essential oils on digestibility and performance in sheep, before recommendation can be made for their use under practical husbandry conditions.

  18. High resolution 4-D spectroscopy with sparse concentric shell sampling and FFT-CLEAN.

    Science.gov (United States)

    Coggins, Brian E; Zhou, Pei

    2008-12-01

    Recent efforts to reduce the measurement time for multidimensional NMR experiments have fostered the development of a variety of new procedures for sampling and data processing. We recently described concentric ring sampling for 3-D NMR experiments, which is superior to radial sampling as input for processing by a multidimensional discrete Fourier transform. Here, we report the extension of this approach to 4-D spectroscopy as Randomized Concentric Shell Sampling (RCSS), where sampling points for the indirect dimensions are positioned on concentric shells, and where random rotations in the angular space are used to avoid coherent artifacts. With simulations, we show that RCSS produces a very low level of artifacts, even with a very limited number of sampling points. The RCSS sampling patterns can be adapted to fine rectangular grids to permit use of the Fast Fourier Transform in data processing, without an apparent increase in the artifact level. These artifacts can be further reduced to the noise level using the iterative CLEAN algorithm developed in radioastronomy. We demonstrate these methods on the high resolution 4-D HCCH-TOCSY spectrum of protein G's B1 domain, using only 1.2% of the sampling that would be needed conventionally for this resolution. The use of a multidimensional FFT instead of the slow DFT for initial data processing and for subsequent CLEAN significantly reduces the calculation time, yielding an artifact level that is on par with the level of the true spectral noise.

  19. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea-ice

    Science.gov (United States)

    Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

    2015-10-01

    The effect of aerosols on clouds and their radiative properties is one of the largest uncertainties in our understanding of radiative forcing. A recent study has concluded that better characterisation of pristine, natural aerosol processes leads to the largest reduction in these uncertainties. Antarctica, being far from anthropogenic activities, is an ideal location for the study of natural aerosol processes. Aerosol measurements in Antarctica are often limited to boundary layer air-masses at spatially sparse coastal and continental research stations, with only a handful of studies in the sea ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the ice-breaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the Polar Front, with mean Polar Cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air-masses quickly from the free-troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea ice boundary layer air-masses travelled equator-ward into the low albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei where, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and

  20. Individual and environmental risk factors for high blood lead concentrations in Danish indoor shooters.

    Science.gov (United States)

    Grandahl, Kasper; Suadicani, Poul; Jacobsen, Peter

    2012-08-01

    International studies have shown blood lead at levels causing health concern in recreational indoor shooters. We hypothesized that Danish recreational indoor shooters would also have a high level of blood lead, and that this could be explained by shooting characteristics and the physical environment at the shooting range. This was an environmental case study of 58 male and female shooters from two indoor shooting ranges with assumed different ventilation and cleaning conditions. Information was obtained on general conditions including age, gender, tobacco and alcohol use, and shooting conditions: weapon type, number of shots fired, frequency of stays at the shooting range and hygiene habits. A venous blood sample was drawn to determine blood lead concentrations; 14 non-shooters were included as controls. Almost 60% of the shooters, hereof five out of 14 women, had a blood lead concentration above 0.48 micromol/l, a level causing long-term health concern. All controls had blood lead values below 0.17 micromol/l. Independent significant associations with blood lead concentrations above 0.48 micromol/l were found for shooting at a poorly ventilated range, use of heavy calibre weapons, number of shots and frequency of stays at the shooting range. A large proportion of Danish recreational indoor shooters had potentially harmful blood lead concentrations. Ventilation, amounts of shooting, use of heavy calibre weapons and stays at the shooting ranges were independently associated with increased blood lead. The technical check at the two ranges was performed by the Danish Technological Institute and costs were defrayed by the Danish Rifle Association. To pay for the analyses of blood lead, the study was supported by the The Else & Mogens Wedell-Wedellsborg Foundation. The Danish Regional Capital Scientific Ethics Committee approved the study, protocol number H-4-2010-130.

  1. Exploiting level anti-crossings for efficient and selective transfer of hyperpolarization in coupled nuclear spin systems

    NARCIS (Netherlands)

    Pravdivtsev, A.N.; Yurkovskaya, A.V.; Kaptein, R.; Miesel, K.; Vieth, H.-M.; Ivanov, K.L.

    2013-01-01

    Spin hyperpolarization can be coherently transferred to other nuclei in field-cycling NMR experiments. At low magnetic fields spin polarization is redistributed in a strongly coupled network of spins. Polarization transfer is most efficient at fields where level anti-crossings (LACs) occur for the

  2. Acute afterload-imposed change in porcine cardiac metabolism imaged by hyperpolarized [1-13C]Pyruvate

    DEFF Research Database (Denmark)

    Tougaard, Rasmus Stilling; Søvsø Szocska Hansen, Esben; Laustsen, Christoffer

    Deranged metabolism is now considered a key causal factor in heart failure and has therefore gained considerable scientific interest. The novel technique hyperpolarized MR has emerged as a leading methodological candidate to study these derangements. We employed a clinically relevant, large animal...

  3. Ex vivo hyperpolarized MR spectroscopy on isolated renal tubular cells: A novel technique for cell energy phenotyping.

    Science.gov (United States)

    Juul, Troels; Palm, Fredrik; Nielsen, Per Mose; Bertelsen, Lotte Bonde; Laustsen, Christoffer

    2017-08-01

    It has been demonstrated that hyperpolarized 13 C MR is a useful tool to study cultured cells. However, cells in culture can alter phenotype, which raises concerns regarding the in vivo significance of such findings. Here we investigate if metabolic phenotyping using hyperpolarized 13 C MR is suitable for cells isolated from kidney tissue, without prior cell culture. Isolation of tubular cells from freshly excised kidney tissue and treatment with either ouabain or antimycin A was investigated with hyperpolarized MR spectroscopy on a 9.4 Tesla preclinical imaging system. Isolation of tubular cells from less than 2 g of kidney tissue generally resulted in more than 10 million live tubular cells. This amount of cells was enough to yield robust signals from the conversion of 13 C-pyruvate to lactate, bicarbonate and alanine, demonstrating that metabolic flux by means of both anaerobic and aerobic pathways can be quantified using this technique. Ex vivo metabolic phenotyping using hyperpolarized 13 C MR in a preclinical system is a useful technique to study energy metabolism in freshly isolated renal tubular cells. This technique has the potential to advance our understanding of both normal cell physiology as well as pathological processes contributing to kidney disease. Magn Reson Med 78:457-461, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  4. Extremely high hole concentrations in c-plane GaN

    Energy Technology Data Exchange (ETDEWEB)

    Trybus, Elaissa; Moseley, Michael; Henderson, Walter; Billingsley, Daniel [Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Namkoong, Gon [Old Dominion University, Applied Research Center, Newport News, VA (United States); Look, David C. [Wright State University, Semiconductor Research Center, Dayton, OH (United States); Doolittle, W.A.

    2009-06-15

    Metal Modulated Epitaxy (S. D. Burnham et al., J. Appl. Phys. 104, 024902 (2008)[1]) is extended to include modulation of both the shutters of Ga and Mg, the Mg being delivered from a Veeco corrosive series valved cracker (S. D. Burnham et al., Mater. Res. Soc. Proc. 798, Y8.11 (2003)[2]). The Ga fluxes used are sufficiently large that droplets rapidly form when the Ga shutter opens and are subsequently depleted when the Ga shutter closes. The result is the ability to limit surface faceting while predominantly growing under average N-rich growth conditions and thus, possibly reduce N-vacancy defects. N-vacancy defects are known to result in compensation. This ability to grow higher quality materials under N-rich conditions results in very high hole concentrations and low resistivity p-type materials. Hole concentrations as high as 2 x 10{sup 19} cm{sup -3} have been achieved on c-plane GaN resulting in resistivities as low as 0.38 ohm-cm. The dependence on Ga flux, shutter timing, the corresponding RHEED images for each condition is detailed and clearly show minimization of faceting and crystal quality variations as determined by X-ray diffraction. Quantification of the Mg incorporation and residual impurities such as hydrogen, oxygen, and carbon by SIMS, eliminates co-doping, while temperature dependent hall measurements show reduced activation energies. X-ray diffraction data compares crystalline quality with hole concentration. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Adaptation to high salt concentrations in halotolerant/ halophilic fungi: a molecular perspective

    Directory of Open Access Journals (Sweden)

    Ana ePlemenitas

    2014-05-01

    Full Text Available Molecular studies of salt tolerance of eukaryotic microorganisms have until recently been limited to the baker’s yeast Saccharomyces cerevisiae and a few other moderately halotolerant yeast. Discovery of the extremely halotolerant and adaptable fungus Hortaea werneckii and the obligate halophile Wallemia ichthyophaga introduced two new model organisms into studies on the mechanisms of salt tolerance in eukaryotes. H. werneckii is unique in its adaptability to fluctuations in salt concentrations, as it can grow without NaCl as well as in the presence of up to 5 M NaCl. On the other hand, W. ichthyophaga requires at least 1.5 M NaCl for growth, but also grows in up to 5 M NaCl. Our studies have revealed the novel and intricate molecular mechanisms used by these fungi to combat high salt concentrations, which differ in many aspects between the extremely halotolerant H. werneckii and the halophilic W. ichthyophaga. Specifically, the high osmolarity glycerol signalling pathway that is important for sensing and responding to increased salt concentrations is here compared between H. werneckii and W. ichthyophaga. In both of these fungi, the key signalling components are conserved, but there are structural and regulation differences between these pathways in H. werneckii and W. ichthyophaga. We also address differences that have been revealed from analysis of their newly sequenced genomes. The most striking characteristics associated with H. werneckii are the large genetic redundancy, the expansion of genes encoding metal cation transporters, and a relatively recent whole genome duplication. In contrast, the genome of W. ichthyophaga is very compact, as only 4,884 protein-coding genes are predicted, which cover almost three quarters of the sequence. Importantly, there has been a significant increase in their hydrophobins, cell-wall proteins that have multiple cellular functions.

  6. Plasmonic Refractive Index Sensor with High Figure of Merit Based on Concentric-Rings Resonator

    Science.gov (United States)

    Zhang, Zhaojian; Yang, Junbo; He, Xin; Zhang, Jingjing; Huang, Jie; Chen, Dingbo; Han, Yunxin

    2018-01-01

    A plasmonic refractive index (RI) sensor based on metal-insulator-metal (MIM) waveguide coupled with concentric double rings resonator (CDRR) is proposed and investigated numerically. Utilizing the novel supermodes of the CDRR, the FWHM of the resonant wavelength can be modulated, and a sensitivity of 1060 nm/RIU with high figure of merit (FOM) 203.8 is realized in the near-infrared region. The unordinary modes, as well as the influence of structure parameters on the sensing performance, are also discussed. Such plasmonic sensor with simple framework and high optical resolution could be applied to on-chip sensing systems and integrated optical circuits. Besides, the special cases of bio-sensing and triple rings are also discussed. PMID:29300331

  7. Derived air concentration for high exposure plutonium : revised values based on ICRP -30 recommendations

    International Nuclear Information System (INIS)

    Sharma, Lata; Janardhanan, S.; Krishnamurthi, T.N.

    1983-01-01

    Derived Air Concentration (DAC) limits for plutonium isotopic mixtures, as obtained from reprocessing of spent fuel heavy water reactors, are presented in this paper. DAC for the mixtures is expressed in terms of alpha activity of plutonium. Growth of 241 Am in the product is taken into consideration. Current recommedations on DAC limits for individual Pu isotopes, as laid down in ICRP-30 report, are used for estimating DAC for the mixture. DACsub(α) for high exposure plutonium is found to be less by a factor of 2-3, when compared with the limit for 239 Pu. As a result, detection and alarm limits for air monitoring instruments should be scaled down while handling high exposure plutonium. (author)

  8. Derived air concentration for high exposure plutonium : revised values based on ICRP -30 recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, L.; Janardhanan, S.; Krishnamurthi, T.N. (Bhabha Atomic Research Centre, Bombay (India). Health Physics Div.)

    Derived Air Concentration (DAC) limits for plutonium isotopic mixtures, as obtained from reprocessing of spent fuel heavy water reactors, are presented in this paper. DAC for the mixtures is expressed in terms of alpha activity of plutonium. Growth of /sup 241/Am in the product is taken into consideration. Current recommedations on DAC limits for individual Pu isotopes, as laid down in ICRP-30 report, are used for estimating DAC for the mixture. DACsub(..cap alpha..) for high exposure plutonium is found to be less by a factor of 2-3, when compared with the limit for /sup 239/Pu. As a result, detection and alarm limits for air monitoring instruments should be scaled down while handling high exposure plutonium.

  9. The uropathogenic species Staphylococcus saprophyticus tolerates a high concentration of D-serine.

    Science.gov (United States)

    Sakinç, Türkân; Michalski, Nadine; Kleine, Britta; Gatermann, Sören G

    2009-10-01

    Human urine contains a relatively high concentration of d-serine, which is toxic to several nonuropathogenic bacteria, but can be utilized or detoxified by uropathogenic Escherichia coli (UPEC). The sequenced genome of uropathogenic Staphylococcus saprophyticus contains a gene with homology to the d-serine deaminase gene (dsdA) of UPEC. We found the gene in several clinical isolates of S. saprophyticus; however, the gene was absent in Staphylococcus xylosus and Staphylococcus cohnii, phylogenetically close relatives of S. saprophyticus, and could also not be detected in isolates of Staphylococcus aureus, Staphylococcus epidermidis and 13 other staphylococcal species. In addition, the genomes of other sequenced staphylococci do not harbor homologues of this operon. Interestingly, S. saprophyticus could grow in media supplemented with relatively high concentrations of d-serine, whereas S. aureus, S. epidermidis and other staphylococcal species could not. The association of the dsdA gene with growth in media including d-serine was proved by introducing the gene into S. aureus Newman. Given the fact that UPEC and S. saprophyticus tolerate this compound, d-serine utilization and detoxification may be a general property of uropathogenic bacteria. © 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  10. High Concentration of Red Clay as an Alternative for Antibiotics in Aquaculture.

    Science.gov (United States)

    Jung, Jaejoon; Jee, Seung Cheol; Sung, Jung-Suk; Park, Woojun

    2016-01-01

    The use of antibiotics in aquaculture raises environmental and food safety concerns because chronic exposure of an aquatic ecosystem to antibiotics can result in the spread of antibiotic resistance, bioaccumulation of antibiotics in the organisms, and transfer of antibiotics to humans. In an attempt to overcome these problems, high-concentration red clay was applied as an alternative antibiotic against the following common fish pathogens: Aeromonas salmonicida, Vibrio alginolyticus, and Streptococcus equinus. The growth of A. salmonicida and V. alginolyticus was retarded by red clay, whereas that of S. equinus was promoted. Phase contrast and scanning electron microscopy analyses confirmed the attachment of red clay on cell surfaces, resulting in rapid gravitational removal and cell surface damage in both A. salmonicida and V. alginolyticus, but not in S. equinus. Different cell wall properties of grampositive species may explain the unharmed cell surface of S. equinus. Significant levels of oxidative stress were generated in only the former two species, whereas significant changes in membrane permeability were found only in S. equinus, probably because of its physiological adaptation. The bacterial communities in water samples from Oncorhynchus mykiss aquacultures supplemented with red clay showed similar structure and diversity as those from oxytetracycline-treated water. Taken together, the antibiotic effects of high concentrations of red clay in aquaculture can be attributed to gravitational removal, cell surface damage, and oxidative stress production, and suggest that red clay may be used as an alternative for antibiotics in aquaculture.

  11. Highly Concentrated Alginate-Gellan Gum Composites for 3D Plotting of Complex Tissue Engineering Scaffolds

    Directory of Open Access Journals (Sweden)

    Ashwini Rahul Akkineni

    2016-04-01

    Full Text Available In tissue engineering, additive manufacturing (AM technologies have brought considerable progress as they allow the fabrication of three-dimensional (3D structures with defined architecture. 3D plotting is a versatile, extrusion-based AM technology suitable for processing a wide range of biomaterials including hydrogels. In this study, composites of highly concentrated alginate and gellan gum were prepared in order to combine the excellent printing properties of alginate with the favorable gelling characteristics of gellan gum. Mixtures of 16.7 wt % alginate and 2 or 3 wt % gellan gum were found applicable for 3D plotting. Characterization of the resulting composite scaffolds revealed an increased stiffness in the wet state (15%–20% higher Young’s modulus and significantly lower volume swelling in cell culture medium compared to pure alginate scaffolds (~10% vs. ~23%. Cytocompatibility experiments with human mesenchymal stem cells (hMSC revealed that cell attachment was improved—the seeding efficiency was ~2.5–3.5 times higher on the composites than on pure alginate. Additionally, the composites were shown to support hMSC proliferation and early osteogenic differentiation. In conclusion, print fidelity of highly concentrated alginate-gellan gum composites was comparable to those of pure alginate; after plotting and crosslinking, the scaffolds possessed improved qualities regarding shape fidelity, mechanical strength, and initial cell attachment making them attractive for tissue engineering applications.

  12. High 5-hydroxymethylfurfural concentrations are found in Malaysian honey samples stored for more than one year.

    Science.gov (United States)

    Khalil, M I; Sulaiman, S A; Gan, S H

    2010-01-01

    5-Hydroxymethylfurfural (HMF) content is an indicator of the purity of honey. High concentrations of HMF in honey indicate overheating, poor storage conditions and old honey. This study investigated the HMF content of nine Malaysian honey samples, as well as the correlation of HMF formation with physicochemical properties of honey. Based on the recommendation by the International Honey Commission, three methods for the determination of HMF were used: (1) high performance liquid chromatography (HPLC), (2) White spectrophotometry and (3) Winkler spectrophotometry methods. HPLC and White spectrophotometric results yielded almost similar values, whereas the Winkler method showed higher readings. The physicochemical properties of honey (pH, free acids, lactones and total acids) showed significant correlation with HMF content and may provide parameters that could be used to make quick assessments of honey quality. The HMF content of fresh Malaysian honey samples stored for 3-6 months (at 2.80-24.87 mg/kg) was within the internationally recommended value (80 mg/kg for tropical honeys), while honey samples stored for longer periods (12-24 months) contained much higher HMF concentrations (128.19-1131.76 mg/kg). Therefore, it is recommended that honey should generally be consumed within one year, regardless of the type. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  13. Performance of high amylose starch-composited gelatin films influenced by gelatinization and concentration.

    Science.gov (United States)

    Wang, Wenhang; Wang, Kun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana; Liu, Anjun

    2017-01-01

    In order to study the impact of starch in film performance, high amylose corn starch was composited in gelatin films under different gelatinization conditions and, in high and low concentrations (10 and 50wt.%). It was found that hot water gelatinized starch (Gel-Shw) increased film mechanical strength and was dependent upon the starch concentration. The addition of an alkali component to the starch significantly enhanced the swelling of the starch granules and expedited the gelatinization process. Incorporation of starch, especially the alkalized starch (Sha), into the gelatin films decreased film solubility which improved its water resistance and water vapor permeability (WVP). Multiple techniques (DSC, TGA, FT-IR, and XRD) were used to characterize the process and results, including the crosslinking of the dissolved starch molecules and the particles formed from gelatinized starch during retrogradation process, which played an important role in improving the thermal stability of the composited gelatin films. Overall, the starch-gelatin composition provides a potential approach to improve gelatin film performance and benefit its applications in the food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Torres-JArdon, R.

    2013-05-01

    Torres-Jardón, R.*, Rosas-Pérez, I., Granada-Macías, L. M., Ruiz-Suárez, L. G. Centro de Ciencias de la Atmósfera, UNAM, México D. F. México * rtorres@unam.mx For many years, the vegetation of forest species such as Abies religiosa in natural parks located in the southwest mountains of Mexico City has attracted much attention since these parks have been experiencing a severe decline of unclear etiology. The high ozone levels in the area and the observed naked eye macroscopic, histological and cytological injuries on these species, strongly suggest an important contribution of tropospheric ozone to this deterioration process. Apart of historical short monitoring campaigns for measuring ozone levels in these mountains, it is known just a little is known about the present exposure levels at which the local vegetation is exposed. A continuous ozone analyzer has been in operation since 2011 at a high-elevation forest site (Parque Nacional Miguel Hidalgo, PNMH; 3110 m above mean sea level) located downwind of Mexico City Metropolitan Area (MCMA), in order to characterize the local ozone diel amplitude and its seasonal trend, as well as the influence of MCMA on the local O3 concentrations. Hourly average ozone data in PNMH shows that in general, the diel of ozone concentrations in the forest site has a statistical significant correlation with the pattern of ozone levels observed in several monitoring sites (smog receptor sites) within the MCMA, although the high elevation O3 levels are relatively lower than those in the urban area (around 2200 m above mean sea level). It is possible that a part of the oxidants in the air masses are removed by sink deposition processes during the air mass transport across the hills. The diel amplitude of ozone concentrations is small in the cold season, increasing as the seasons advance to June. As in the city, the highest ozone concentrations occur in April or May and the lowest levels during the rainy season, which extends from

  15. Development of a hyperpolarized 129Xe system on 3T for the rat lungs

    International Nuclear Information System (INIS)

    Sato, Hiroshi; Enmi, Jun-ichiro; Hayashi, Takuya

    2004-01-01

    MRI (magnetic resonance imaging) with 129 Xe has gained much attention as a diagnostic methodology because of its affinity for lipids and possible polarization. The quantitative estimation of net detectability and stability of hyperpolarized 129 Xe in the dissolved phase in vivo is valuable to the development of clinical applications. The goal of this study was to develop a stable hyperpolarized 129 Xe experimental 3T system to statistically analyze the dissolved-phase 129 Xe signal in the rat lungs. The polarization of 129 Xe with buffer gases at the optical pumping cell was measured under adiabatic fast passage against the temperature of an oven and laser absorption at the cell. The gases were insuffiated into the lungs of Sprague-Dawley rats (n=15, 400-550 g) through an endotracheal tube under spontaneous respiration. Frequency-selective spectroscopy was performed for the gas phase and dissolved phase. We analyzed the 129 Xe signal in the dissolved phase to measure the chemical shift, T 2 * , delay and its ratio in a rat lungs on 3T. The polarizer was able to produce polarized gas (1.1±0.47%, 120 cm 3 ) hundreds of times with the laser absorption ratio (25%) kept constant at the cell. The optimal buffer gas ratio of 25-50% rendered the maximum signal in the dissolved phase. Two dominant peaks of 211.8±0.9 and 201.1±0.6 ppm were observed with a delay of 0.4±0.9 and 0.9±1.0 s from the gas phase spectra. The ratios of their average signal to that of the gas phase were 5.6±5.2% and 4.4±4.7%, respectively. The T 2 * of the air space in the lungs was 2.5±0.5 ms, which was 3.8 times shorter than that in a syringe. We developed a hyperpolarized 129 Xe experimental system using a 3T MRI scanner that yields sufficient volume and polarization and quantitatively analyzed the dissolved-phase 129 Xe signal in the rat lungs. (author)

  16. Volumetric spiral chemical shift imaging of hyperpolarized [2-(13) c]pyruvate in a rat c6 glioma model.

    Science.gov (United States)

    Park, Jae Mo; Josan, Sonal; Jang, Taichang; Merchant, Milton; Watkins, Ron; Hurd, Ralph E; Recht, Lawrence D; Mayer, Dirk; Spielman, Daniel M

    2016-03-01

    MRS of hyperpolarized [2-(13)C]pyruvate can be used to assess multiple metabolic pathways within mitochondria as the (13)C label is not lost with the conversion of pyruvate to acetyl-CoA. This study presents the first MR spectroscopic imaging of hyperpolarized [2-(13)C]pyruvate in glioma-bearing brain. Spiral chemical shift imaging with spectrally undersampling scheme (1042 Hz) and a hard-pulse excitation was exploited to simultaneously image [2-(13)C]pyruvate, [2-(13)C]lactate, and [5-(13)C]glutamate, the metabolites known to be produced in brain after an injection of hyperpolarized [2-(13)C]pyruvate, without chemical shift displacement artifacts. A separate undersampling scheme (890 Hz) was also used to image [1-(13)C]acetyl-carnitine. Healthy and C6 glioma-implanted rat brains were imaged at baseline and after dichloroacetate administration, a drug that modulates pyruvate dehydrogenase kinase activity. The baseline metabolite maps showed higher lactate and lower glutamate in tumor as compared to normal-appearing brain. Dichloroacetate led to an increase in glutamate in both tumor and normal-appearing brain. Dichloroacetate-induced %-decrease of lactate/glutamate was comparable to the lactate/bicarbonate decrease from hyperpolarized [1-(13)C]pyruvate studies. Acetyl-carnitine was observed in the muscle/fat tissue surrounding the brain. Robust volumetric imaging with hyperpolarized [2-(13)C]pyruvate and downstream products was performed in glioma-bearing rat brains, demonstrating changes in mitochondrial metabolism with dichloroacetate. © 2015 Wiley Periodicals, Inc.

  17. Rapid assessment of pulmonary gas transport with hyperpolarized 129Xe MRI using a 3D radial double golden-means acquisition with variable flip angles.

    Science.gov (United States)

    Ruppert, Kai; Amzajerdian, Faraz; Hamedani, Hooman; Xin, Yi; Loza, Luis; Achekzai, Tahmina; Duncan, Ian F; Profka, Harrilla; Siddiqui, Sarmad; Pourfathi, Mehrdad; Cereda, Maurizio F; Kadlecek, Stephen; Rizi, Rahim R

    2018-04-22

    To demonstrate the feasibility of using a 3D radial double golden-means acquisition with variable flip angles to monitor pulmonary gas transport in a single breath hold with hyperpolarized xenon-129 MRI. Hyperpolarized xenon-129 MRI scans with interleaved gas-phase and dissolved-phase excitations were performed using a 3D radial double golden-means acquisition in mechanically ventilated rabbits. The flip angle was either held fixed at 15 ° or 5 °, or it was varied linearly in ascending or descending order between 5 ° and 15 ° over a sampling interval of 1000 spokes. Dissolved-phase and gas-phase images were reconstructed at high resolution (32 × 32 × 32 matrix size) using all 1000 spokes, or at low resolution (22 × 22 × 22 matrix size) using 400 spokes at a time in a sliding-window fashion. Based on these sliding-window images, relative change maps were obtained using the highest mean flip angle as the reference, and aggregated pixel-based changes were tracked. Although the signal intensities in the dissolve-phase maps were mostly constant in the fixed flip-angle acquisitions, they varied significantly as a function of average flip angle in the variable flip-angle acquisitions. The latter trend reflects the underlying changes in observed dissolve-phase magnetization distribution due to pulmonary gas uptake and transport. 3D radial double golden-means acquisitions with variable flip angles provide a robust means for rapidly assessing lung function during a single breath hold, thereby constituting a particularly valuable tool for imaging uncooperative or pediatric patient populations. © 2018 International Society for Magnetic Resonance in Medicine.

  18. Technique development of 3D dynamic CS-EPSI for hyperpolarized 13 C pyruvate MR molecular imaging of human prostate cancer.

    Science.gov (United States)

    Chen, Hsin-Yu; Larson, Peder E Z; Gordon, Jeremy W; Bok, Robert A; Ferrone, Marcus; van Criekinge, Mark; Carvajal, Lucas; Cao, Peng; Pauly, John M; Kerr, Adam B; Park, Ilwoo; Slater, James B; Nelson, Sarah J; Munster, Pamela N; Aggarwal, Rahul; Kurhanewicz, John; Vigneron, Daniel B

    2018-03-25

    The purpose of this study was to develop a new 3D dynamic carbon-13 compressed sensing echoplanar spectroscopic imaging (EPSI) MR sequence and test it in phantoms, animal models, and then in prostate cancer patients to image the metabolic conversion of hyperpolarized [1- 13 C]pyruvate to [1- 13 C]lactate with whole gland coverage at high spatial and temporal resolution. A 3D dynamic compressed sensing (CS)-EPSI sequence with spectral-spatial excitation was designed to meet the required spatial coverage, time and spatial resolution, and RF limitations of the 3T MR scanner for its clinical translation for prostate cancer patient imaging. After phantom testing, animal studies were performed in rats and transgenic mice with prostate cancers. For patient studies, a GE SPINlab polarizer (GE Healthcare, Waukesha, WI) was used to produce hyperpolarized sterile GMP [1- 13 C]pyruvate. 3D dynamic 13 C CS-EPSI data were acquired starting 5 s after injection throughout the gland with a spatial resolution of 0.5 cm 3 , 18 time frames, 2-s temporal resolution, and 36 s total acquisition time. Through preclinical testing, the 3D CS-EPSI sequence developed in this project was shown to provide the desired spectral, temporal, and spatial 5D HP 13 C MR data. In human studies, the 3D dynamic HP CS-EPSI approach provided first-ever simultaneously volumetric and dynamic images of the LDH-catalyzed conversion of [1- 13 C]pyruvate to [1- 13 C]lactate in a biopsy-proven prostate cancer patient with full gland coverage. The results demonstrate the feasibility to characterize prostate cancer metabolism in animals, and now patients using this new 3D dynamic HP MR technique to measure k PL , the kinetic rate constant of [1- 13 C]pyruvate to [1- 13 C]lactate conversion. © 2018 International Society for Magnetic Resonance in Medicine.

  19. High-concentration boron doping of graphene nanoplatelets by simple thermal annealing and their supercapacitive properties

    Science.gov (United States)

    Yeom, Da-Young; Jeon, Woojin; Tu, Nguyen Dien Kha; Yeo, So Young; Lee, Sang-Soo; Sung, Bong June; Chang, Hyejung; Lim, Jung Ah; Kim, Heesuk

    2015-05-01

    For the utilization of graphene in various energy storage and conversion applications, it must be synthesized in bulk with reliable and controllable electrical properties. Although nitrogen-doped graphene shows a high doping efficiency, its electrical properties can be easily affected by oxygen and water impurities from the environment. We here report that boron-doped graphene nanoplatelets with desirable electrical properties can be prepared by the simultaneous reduction and boron-doping of graphene oxide (GO) at a high annealing temperature. B-doped graphene nanoplatelets prepared at 1000 °C show a maximum boron concentration of 6.04 ± 1.44 at %, which is the highest value among B-doped graphenes prepared using various methods. With well-mixed GO and g-B2O3 as the dopant, highly uniform doping is achieved for potentially gram-scale production. In addition, as a proof-of-concept, highly B-doped graphene nanoplatelets were used as an electrode of an electrochemical double-layer capacitor (EDLC) and showed an excellent specific capacitance value of 448 F/g in an aqueous electrolyte without additional conductive additives. We believe that B-doped graphene nanoplatelets can also be used in other applications such as electrocatalyst and nano-electronics because of their reliable and controllable electrical properties regardless of the outer environment.

  20. High-concentration boron doping of graphene nanoplatelets by simple thermal annealing and their supercapacitive properties.

    Science.gov (United States)

    Yeom, Da-Young; Jeon, Woojin; Tu, Nguyen Dien Kha; Yeo, So Young; Lee, Sang-Soo; Sung, Bong June; Chang, Hyejung; Lim, Jung Ah; Kim, Heesuk

    2015-05-05

    For the utilization of graphene in various energy storage and conversion applications, it must be synthesized in bulk with reliable and controllable electrical properties. Although nitrogen-doped graphene shows a high doping efficiency, its electrical properties can be easily affected by oxygen and water impurities from the environment. We here report that boron-doped graphene nanoplatelets with desirable electrical properties can be prepared by the simultaneous reduction and boron-doping of graphene oxide (GO) at a high annealing temperature. B-doped graphene nanoplatelets prepared at 1000 °C show a maximum boron concentration of 6.04 ± 1.44 at %, which is the highest value among B-doped graphenes prepared using various methods. With well-mixed GO and g-B2O3 as the dopant, highly uniform doping is achieved for potentially gram-scale production. In addition, as a proof-of-concept, highly B-doped graphene nanoplatelets were used as an electrode of an electrochemical double-layer capacitor (EDLC) and showed an excellent specific capacitance value of 448 F/g in an aqueous electrolyte without additional conductive additives. We believe that B-doped graphene nanoplatelets can also be used in other applications such as electrocatalyst and nano-electronics because of their reliable and controllable electrical properties regardless of the outer environment.

  1. Use of high concentration contrast media (HCCM): principles and rationale--body CT

    International Nuclear Information System (INIS)

    Brink, James A.

    2003-01-01

    Numerous complex pharmacokinetic interrelationships affect the use of contrast media for computed tomography (CT) imaging. The volume, concentration, and rate of injection, all affect the degree of enhancement that is achieved with an injection of contrast material. In addition, the injection technique, whether the contrast is infused with a constant injection rate (uniphasic injection) or whether the rate is altered during the injection (multiphasic injection) also affect the magnitude and duration of contrast enhancement. In body CT imaging, the liver poses unique challenges in managing the use of intravenous contrast material because of its dual blood supply and the need to complete imaging before equilibrium occurs between the intravascular and extravascular compartments. The magnitude of hepatic enhancement that is ultimately achieved is related primarily to the amount of iodinated contrast material that accumulates in the extravascular space within the target organ, independent of the speed of the CT scanner. The key determinant of the onset of the equilibrium phase is the injection duration. Given that a high injection flow rate (4-5 ml/s) is desirable for arterial phase imaging, the injection duration is maintained with use of an appropriate contrast volume. Thus, modifications of total iodine dose are best done with alterations in contrast concentration. The magnitude of arterial enhancement that is achieved is related to both the concentration and rate of contrast administration. The speed of the scanner determines its ability to record image data during the most advantageous time period, the peak of arterial enhancement. Thus, rapid imaging is particularly advantageous for optimal contrast use in CT angiography as well as in multiphasic imaging of the parenchymal organs

  2. Ultrafine particles in inhabited areas in the Arctic - From very low to high concentrations

    DEFF Research Database (Denmark)

    Pétursdóttir, Una; Kirkelund, Gunvor Marie; Press-Kristensen, Kåre

    2017-01-01

    The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d < 100 nm) in the town Sisimiut and two nearby settlements, Sarfann......The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d ..., Sarfannguit and Itilleq, in West Greenland. Measurements were carried out during three weeks in April and May 2016. Air temperatures during the measurements ranged from −4.4 to +8.7 °C. A portable condensation particle counter (P-Trak) was used for the measurements. Results showed that the lowest...... in Sisimiut, while subsequent measurements at the same location showed much lower PNCs. The presence of heavy machinery elevated PNCs highly during two measurement events, giving PNCs up to 270,993 cm−3 but dropping to 1180 cm−3 10 min later, after the vehicle had passed by. A measurement event in Sisimiut...

  3. A study of building structural features associated with high indoor air concentrations of organochlorine termiticides.

    Science.gov (United States)

    Pisaniello, D L; Gun, R T; Tkaczuk, M N; Hann, C; Crea, J

    1993-09-01

    As part of a two-year study of post-treatment residential exposure to the termiticide, aldrin, the building structural features of ten houses with crawl-space-type floors were assessed by an independent inspector. Building attributes recorded on a checklist included the age of the dwelling, room characteristics, floor details and the nature of subfloor ventilation. At the end of each inspection, the inspector, who was blinded to data on airborne aldrin concentrations, provided a rating of expected indoor air contamination. Several of the building attributes, including the age of the house, the area of exterior subfloor vents, as well as the inspector's rating, were significantly correlated with airborne aldrin values. No single building variable, however, was highly correlated with every measure of aldrin concentration over a 12-month period. The observed data are consistent with poor subfloor ventilation and a 'leaky' floor being important contributors to indoor air pollution. It is recommended that pest control companies advise householders about any obvious floor and ventilation deficiencies before soil treatment work is undertaken. Pesticide exposure (by analogy with geological radon exposure) may be reduced by sealing gaps in floors and/or by improving subfloor ventilation.

  4. High Concentrations of Organic Contaminants in Air from Ship Breaking Activities in Chittagong, Bangladesh.

    Science.gov (United States)

    Nøst, Therese H; Halse, Anne K; Randall, Scott; Borgen, Anders R; Schlabach, Martin; Paul, Alak; Rahman, Atiqur; Breivik, Knut

    2015-10-06

    The beaches on the coast of Chittagong in Bangladesh are one of the most intense ship breaking areas in the world. The aim of the study was to measure the concentrations of organic contaminants in the air in the city of Chittagong, including the surrounding ship breaking areas using passive air samplers (N = 25). The compounds detected in the highest amounts were the polycyclic aromatic hydrocarbons (PAHs) and short-chain chlorinated paraffins (SCCPs), whereas dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs) were several orders of magnitude lower in comparison. PCBs, PAHs, and HCB were highest at sites near the ship breaking activities, whereas DDTs and SCCPs were higher in the urban areas. Ship breaking activities likely act as atmospheric emission sources of PCBs, PAHs, and HCB, thus adding to the international emphasis on responsible recycling of ships. Concentrations of PAHs, PCBs, DDTs, HCB, and SCCPs in ambient air in Chittagong are high in comparison to those found in similar studies performed in other parts of Asia. Estimated toxic equivalent quotients indicate elevated human health risks caused by inhalation of PAHs at most sites.

  5. Novel approach in k0-NAA for highly concentrated REE Samples.

    Science.gov (United States)

    Abdollahi Neisiani, M; Latifi, M; Chaouki, J; Chilian, C

    2018-04-01

    The present paper presents a new approach for k 0 -NAA for accurate quantification with short turnaround analysis times for rare earth elements (REEs) in high content mineral matrices. REE k 0 and Q 0 values, spectral interferences and nuclear interferences were experimentally evaluated and improved with Alfa Aesar Specpure Plasma Standard 1000mgkg -1 mono-rare earth solutions. The new iterative gamma-ray self-attenuation and neutron self-shielding methods were investigated with powder standards prepared from 100mg of 99.9% Alfa Aesar mono rare earth oxide diluted with silica oxide. The overall performance of the new k 0 -NAA method for REEs was validated using a certified reference material (CRM) from Canadian Certified Reference Materials Project (REE-2) with REE content ranging from 7.2mgkg -1 for Yb to 9610mgkg -1 for Ce. The REE concentration was determined with uncertainty below 7% (at 95% confidence level) and proved good consistency with the CRM certified concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Arbuscular mycorrhizal fungi differentially affect the response to high zinc concentrations of two registered poplar clones

    International Nuclear Information System (INIS)

    Lingua, Guido; Franchin, Cinzia; Todeschini, Valeria; Castiglione, Stefano; Biondi, Stefania; Burlando, Bruno; Parravicini, Valerio; Torrigiani, Patrizia; Berta, Graziella

    2008-01-01

    The effects of a high concentration of zinc on two registered clones of poplar (Populus alba Villafranca and Populus nigra Jean Pourtet), inoculated or not with two arbuscular mycorrhizal fungi (Glomus mosseae or Glomus intraradices) before transplanting them into polluted soil, were investigated, with special regard to the extent of root colonization by the fungi, plant growth, metal accumulation in the different plant organs, and leaf polyamine concentration. Zinc accumulation was lower in Jean Pourtet than in Villafranca poplars, and it was mainly translocated to the leaves; the metal inhibited mycorrhizal colonization, compromised plant growth, and, in Villafranca, altered the putrescine profile in the leaves. Most of these effects were reversed or reduced in plants pre-inoculated with G. mosseae. Results indicate that poplars are suitable for phytoremediation purposes, confirming that mycorrhizal fungi can be useful for phytoremediation, and underscore the importance of appropriate combinations of plant genotypes and fungal symbionts. - Inoculation with arbuscular mycorrhizal fungi can improve poplar tolerance to heavy metals in phytoremediation programmes

  7. High concentration tritium gas measurement with small volume ionization chambers for fusion fuel gas monitors

    International Nuclear Information System (INIS)

    Uda, Tatsuhiko; Okuno, Kenji; Matsuda, Yuji; Naruse, Yuji

    1991-01-01

    To apply ionization chambers to fusion fuel gas processing systems, high concentration tritium gas was experimentally measured with small volume 0.16 and 21.6 cm 3 ionization chambers. From plateau curves, the optimum electric field strength was obtained as 100∼200 V/cm. Detection efficiency was confirmed as dependent on the ionization ability of the filled gas, and moreover on its stopping power, because when the range of the β-rays was shortened, the probability of energy loss by collisions with the electrode and chamber wall increased. Loss of ions by recombination was prevented by using a small volume ionization chamber. For example the 0.16 cm 3 ionization chamber gave measurement with linearity to above 40% tritium gas. After the tritium gas measurements, the concentration levels inside the chamber were estimated from their memory currents. Although more than 1/4,000 of the maximum, current was observed as a memory effect, the smaller ionization chamber gave a smaller memory effect. (author)

  8. Nitrogen concentration profiles in oxy-nitrited high-speed steel

    International Nuclear Information System (INIS)

    Barcz, A.; Turos, A.; Wielunski, L.

    1976-01-01

    Nuclear microanalysis has been applied for the determination of in-depth concentration profiles of nitrogen in oxy-nitrided high-speed steel. The concentration profiles were deduced from measurements of the nitrogen content, determined by means of the 14 N(d,α) 12 C reaction for the set of initially identical samples after the removal of surface layers of sequentially increasing thicknesses. The 1.2 MeV deuterons were obtained from the Institute of Nuclear Research Van de Graaf accelerator LECH. The α-particles produced in the 14 N(d,α) 12 C reaction were detected by means of silicon surface barrier detector mounted at 150 deg C. Strong blocking of the nitrogen diffusion due to the presence of oxygen has been observed. The accuracy of nitrogen detection is of the order of 5% for nitrogen-rich regions and 10% for the matrix. However, the local non-uniformity of the steel may cause a spread of about 20% of the measured values. (T.G.)

  9. Concentrations of radionuclides in cassava growing in high background radiation area and their transfer

    Energy Technology Data Exchange (ETDEWEB)

    Jialin, Huang; Yongru, Zha; Yicao, Guo

    1985-04-01

    The concentrations of several natural radionuclides in common cassava (Manihot esculenta Crantz) growing in Yangjiang County, a high background radiation area in Guangdong Province, and their uptake from soil and distribution in the plant were investigated. The results show that the concentrations of natural uranium and thorium in cassava root are of the order of 10/sup -6/ g/kg, and those of radium-226, radium-228, lead-210 and polonium-210 are of the order of 10/sup -11/ Ci/kg. The highest level is 9.30 +- 0.30 x 10/sup -11/ Ci/kg (lead-210), and the lowest is 3.99 +- 0.20 x 10/sup -11/ Ci/kg (radium-226). The levels of natural uranium, thorium, radium-226 and polonium-210 in cassava are below the limits stipulated by the regulations for food hygiene in China, while the lead-210 level approaches the limit. It is noticeable that the highest level of radium-228 is 7.28 +- 1.03 x 10/sup -11/ Ci/kg, 10.4 times higher than the limit. The transfer of all the nuclides from soil to different parts of cassava shows a pattern contrary to that of he nuclides in the other regions where uranium-and radium-containing waste water and phosphate fertilizer are used in agriculture.

  10. Concentrations of radionuclides in cassava growing in high background radiation area and their transfer

    International Nuclear Information System (INIS)

    Huang Jialin; Zha Yongru; Guo Yicao

    1985-01-01

    The concentrations of several natural radionuclides in common cassava (Manihot esculenta Crantz) growing in Yangjiang County, a high background radiation area in Guangdong Province, and their uptake from soil and distribution in the plant were investigated. The results show that the concentrations of natural uranium and thorium in cassava root are of the order of 10 -6 g/kg, and those of radium-226, radium-228, lead-210 and polonium-210 are of the order of 10 -11 Ci/kg. The highest level is 9.30 +- 0.30 x 10 -11 Ci/kg (lead-210), and the lowest is 3.99 +- 0.20 x 10 -11 Ci/kg (radium-226). The levels of natural uranium, thorium, radium-226 and polonium-210 in cassava are below the limits stipulated by the regulations for food hygiene in China, while the lead-210 level approaches the limit. It is noticeable that the highest level of radium-228 is 7.28 +- 1.03 x 10 -11 Ci/kg, 10.4 times higher than the limit. The transfer of all he nuclides from soil to different parts of cassava shows a pattern contrary to that of he nuclides in the other regions where uranium-and radium-containing waste water and phosphate fertilizer are used in agriculture

  11. Highly efficient luminescent solar concentrators based on earth-abundant indirect-bandgap silicon quantum dots

    Science.gov (United States)

    Meinardi, Francesco; Ehrenberg, Samantha; Dhamo, Lorena; Carulli, Francesco; Mauri, Michele; Bruni, Francesco; Simonutti, Roberto; Kortshagen, Uwe; Brovelli, Sergio

    2017-02-01

    Building-integrated photovoltaics is gaining consensus as a renewable energy technology for producing electricity at the point of use. Luminescent solar concentrators (LSCs) could extend architectural integration to the urban environment by realizing electrode-less photovoltaic windows. Crucial for large-area LSCs is the suppression of reabsorption losses, which requires emitters with negligible overlap between their absorption and emission spectra. Here, we demonstrate the use of indirect-bandgap semiconductor nanostructures such as highly emissive silicon quantum dots. Silicon is non-toxic, low-cost and ultra-earth-abundant, which avoids the limitations to the industrial scaling of quantum dots composed of low-abundance elements. Suppressed reabsorption and scattering losses lead to nearly ideal LSCs with an optical efficiency of η = 2.85%, matching state-of-the-art semi-transparent LSCs. Monte Carlo simulations indicate that optimized silicon quantum dot LSCs have a clear path to η > 5% for 1 m2 devices. We are finally able to realize flexible LSCs with performances comparable to those of flat concentrators, which opens the way to a new design freedom for building-integrated photovoltaics elements.

  12. Human parvovirus B19 infection in hemophiliacs first infused with two high-purity, virally attenuated factor VIII concentrates.

    Science.gov (United States)

    Azzi, A; Ciappi, S; Zakvrzewska, K; Morfini, M; Mariani, G; Mannucci, P M

    1992-03-01

    Human parvovirus B19 can be transmitted by coagulation factor concentrates and is highly resistant to virucidal methods. To evaluate whether the additional removal of virus by chromatographic methods during the manufacture of high-purity concentrates reduces the risk of B19 transmission, we have prospectively evaluated the rate of anti-B19 seroconversion in two groups of susceptible (anti-B19 negative) hemophiliacs infused with high-purity, heated (pasteurized) or solvent-detergent-treated factor VIII concentrates. Both products infected a relatively high proportion of patients (nine of 20).

  13. Probing the porosity of cocrystallized MCM-49/ZSM-35 zeolites by hyperpolarized 129Xe NMR.

    Science.gov (United States)

    Liu, Yong; Zhang, Weiping; Xie, Sujuan; Xu, Longya; Han, Xiuwen; Bao, Xinhe

    2008-01-31

    One- and two-dimensional 129Xe NMR spectroscopy has been employed to study the porosity of cocrystallized MCM-49/ZSM-35 zeolites under the continuous flow of hyperpolarized xenon gas. It is found by variable-temperature experiments that Xe atoms can be adsorbed in different domains of MCM-49/ZSM-35 cocrystallized zeolites and the mechanically mixed counterparts. The exchange of Xe atoms in different types of pores is very fast at ambient temperatures. Even at very low temperature two-dimensional exchange spectra (EXSY) show that Xe atoms still undergo much faster exchange between MCM-49 and ZSM-35 analogues in the cocrystallized zeolites than in the mechanical mixture. This demonstrates that the MCM-49 and ZSM-35 analogues in cocrystallized zeolites may be stacked much closer than in the physical mixture, and some parts of intergrowth may be formed due to the partially similar basic structure of MCM-49 and ZSM-35.

  14. Effects of pyruvate dose on in vivo metabolism and quantification of hyperpolarized 13C spectra

    DEFF Research Database (Denmark)

    Janich, M. A.; Menzel, M. I.; Wiesinger, F.

    2012-01-01

    Real‐time in vivo measurements of metabolites are performed by signal enhancement of [1‐13C]pyruvate using dynamic nuclear polarization, rapid dissolution and intravenous injection, acquisition of free induction decay signals and subsequent quantification of spectra. The commonly injected dose...... uptake and metabolic conversion. The goal of this study was to examine the effects of a [1‐13C]pyruvate bolus on metabolic conversion in vivo. Spectra were quantified by three different methods: frequency‐domain fitting with LCModel, time‐domain fitting with AMARES and simple linear least‐squares fitting...... in the time domain. Since the simple linear least‐squares approach showed bleeding artifacts and LCModel produced noisier time signals. AMARES performed best in the quantification of in vivo hyperpolarized pyruvate spectra. We examined pyruvate doses of 0.1–0.4 mmol/kg (body mass) in male Wistar rats...

  15. Effects of anesthesia on renal function and metabolism in rats assessed by hyperpolarized MRI

    DEFF Research Database (Denmark)

    Qi, Haiyun; Mariager, Christian Østergaard; Lindhardt, Jakob

    2018-01-01

    . In the present study, we aimed to investigate the renal functional and metabolic consequences of 3 typical rodent anesthetics used in preclinical MRI: sevoflurane, inaction, and a mixture of fentanyl, fluanisone, and midazolam (FFM). METHODS: The renal effects of 3 different classes of anesthetics (inactin......, servoflurane, and FFM) were investigated using functional and metabolic MRI. The renal glucose metabolism and hemodynamics was characterized with hyperpolarized [1-13C]pyruvate MRI and by DCE imaging. RESULTS: Rats receiving sevoflurane or FFM had blood glucose levels that were 1.3-fold to 1.4-fold higher than...... rats receiving inactin. A 2.9-fold and 4.8-fold increased13C-lactate/13C-pyruvate ratio was found in the FFM mixture anesthetized group compared with the sevoflurane and the inactin anesthetized groups. The FFM anesthesia resulted in a 50% lower renal plasma flow compared with the sevoflurane...

  16. Acute renal metabolic effect of metformin treatment assessed with hyperpolarized magnetic resonance imaging

    DEFF Research Database (Denmark)

    Qi, Haiyun; Nielsen, Per Mose; Schroeder, Marie

    2017-01-01

    Metformin is the primary anti-diabetic drug in type-2 diabetes patients. However, controversy exists on its use in patients with renal impairment. Here we investigated the acute metabolic effects of metformin treatment in rat kidneys, with hyperpolarized 13C pyruvate and Clark......-electrodes. A significantly altered metabolic phenotype was observed 30 min post metformin treatment. Anaerobic metabolism was elevated in the cytosol, indicated by increased lactate/pyruvate ratio, and mitochondrial aerobic metabolism was reduced, indicated by decreased bicarbonate/pyruvate ratio. Acute metformin treatment...... increased renal blood flow with higher O2 saturation and did not change tubular O2 consumption. These results indicate that metformin reduces mitochondrial respiration and enhances anaerobic metabolism, even with enough oxygen supply, within only 30 min of treatment....

  17. The protective role of low-concentration alcohol in high-fructose induced adverse cardiovascular events in mice.

    Science.gov (United States)

    Wu, Xiaoqi; Pan, Bo; Wang, Ying; Liu, Lingjuan; Huang, Xupei; Tian, Jie

    2018-01-01

    Cardiovascular disease remains a worldwide public health issue. As fructose consumption is dramatically increasing, it has been demonstrated that a fructose-rich intake would increase the risk of cardiovascular disease. In addition, emerging evidences suggest that low concentration alcohol intake may exert a protective effect on cardiovascular system. This study aimed to investigate whether low-concentration alcohol consumption would prevent the adverse effects on cardiovascular events induced by high fructose in mice. From the results of hematoxylin-eosin staining, echocardiography, heart weight/body weight ratio and the expression of hypertrophic marker ANP, we found high-fructose result in myocardial hypertrophy and the low-concentration alcohol consumption would prevent the cardiomyocyte hypertrophy from happening. In addition, we observed low-concentration alcohol consumption could inhibit mitochondria swollen induced by high-fructose. The elevated levels of glucose, triglyceride, total cholesterol in high-fructose group were reduced by low concentration alcohol. Low expression levels of SIRT1 and PPAR-γ induced by high-fructose were significantly elevated when fed with low-concentration alcohol. The histone lysine 9 acetylation (acH3K9) level was decreased in PPAR-γ promoter in high-fructose group but elevated when intake with low concentration alcohol. The binding levels of histone deacetylase SIRT1 were increased in the same region in high-fructose group, while the low concentration alcohol can prevent the increased binding levels. Overall, our study indicates that low-concentration alcohol consumption could inhibit high-fructose related myocardial hypertrophy, cardiac mitochondria damaged and disorders of glucose-lipid metabolism. Furthermore, these findings also provide new insights into histone acetylation-deacetylation mechanisms of low-concentration alcohol treatment that may contribute to the prevention of cardiovascular disease induced by high

  18. Bottom-Up Cost Analysis of a High Concentration PV Module; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, K.; Woodhouse, M.; Lee, H.; Smestad, G.

    2015-04-13

    We present a bottom-up model of III-V multi-junction cells, as well as a high concentration PV (HCPV) module. We calculate $0.65/Wp(DC) manufacturing costs for our model HCPV module design with today’s capabilities, and find that reducing cell costs and increasing module efficiency offer the promising pathways for future cost reductions. Cell costs could be significantly reduced via an increase in manufacturing scale, substrate reuse, and improved manufacturing yields. We also identify several other significant drivers of HCPV module costs, including the Fresnel lens primary optic, module housing, thermal management, and the receiver board. These costs could potentially be lowered by employing innovative module designs.

  19. EPRI 25kW high concentration photovoltaic integrated array concept and associated economics

    International Nuclear Information System (INIS)

    Gunn, J.A.; Dostalek, F.J.

    1993-01-01

    This paper describes a cost effective photovoltaic array design for the high concentration technology being developed by the Electric Power Research Institute for utility scale applications. The concept of an ''integrated array'' is to attach Fresnel lens parquets directly to the front of the tracker structure and PV panels directly to the back of the structure thereby eliminating redundant structural components. The concept also incorporates the maximum use of automated manufacturing techniques for all components thereby minimizing material waste, fabrication and assembly labor. This paper also describes the results of a first approach cost and economic study for the technology which shows the potential for levelized energy cost below $0.10/kWh for a 50 MW ac plant given a mature technology

  20. Ozone concentration characteristics in and over a high-altitude forest

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, G.L.; Zeller, K.F.; Musselman, R.C. [USDA Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO (United States)

    1994-12-31

    Four years of atmospheric ozone data from a subalpine forest site at an elevation of 3180 m above mean sea level (msl) about 55 km west of Laramie, Wyoming, U.S.A., and at a 2680 msl forest-steppe ecotone site 15 km to the southeast, have been analyzed. These sites appear to be free of any urban or industrial pollutants. Data for January through June show that the amplitude of the diurnal cycle of hourly mean values is small in winter, then increases through June. The highest monthly mean concentrations occur in April or May, and decrease in June. Episodal high O{sub 3} values were measured during spring months in connection with cutoff low pressure centers aloft and probable stratospheric intrusions. Spectral analyses yield a peak at the diurnal period and broad peaks at longer periodicities, particularly during the spring season. (orig.)

  1. Formulation and make-up of simulated concentrated water, high ionic content aqueous solution

    International Nuclear Information System (INIS)

    Gdowski, G.

    1997-01-01

    This procedure describes the formulation and make-up of Simulated Concentrated Water (SCW), a high-ionic-content water to be used for Activity E-20-50 Long-Term Corrosion Studies. This water has an ionic content which is nominally a factor of a thousand higher than that of representative waters at or near Yucca Mountain. Representative waters were chosen as J-13 well water [Harrar, 1990] and perched water at Yucca Mountain [Glassley, 1996]. J-13 well water is obtained from ground water that is in contact with the Topopah Spring tuff, which is the repository horizon rock. The perched water is located in the Topopah Spring tuff, but below the repository horizon and above the water table. A nominal thousand times higher ionic content was chosen to simulate the water that would result from the wetting of salts which have been previously deposited on a container surface

  2. Study on radon concentration monitoring using activated charcoal canisters in high humidity environments

    International Nuclear Information System (INIS)

    Wang Yuexing; Wang Haijun; Yang Yifang; Qin Sichang; Wang Zhentao; Zhang Zhenjiang

    2009-01-01

    The effects of humidity on the sensitivity using activated charcoal canisters for measuring radon concentrations in high humidity environments were studied. Every canister filled with 80 g of activated charcoal, and they were exposed to 48 h or 72 h in the relative humidity of 68%, 80%, 88% and 96% (28 degree C), respectively. The amount of radon absorbed in the canisters was determined by counting the gamma rays from 214 Pb and 214 Bi (radon progeny). The results showed that counts decreased with the increase of relative humidity. There was a negative linear relationship between count and humidity. In the relative humidity range of 68%-96%, the sensitivity of radon absorption decreased about 2.4% for every 1% (degree)rise in humidity. The results also showed that the exposure time of the activated charcoal canisters should be less than 3 days. (authors)

  3. Cesium Isotherm Testing with Spherical Resorcinol-Formaldehyde Resin at High Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smoot, Margaret R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rinehart, Donald E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-04-01

    Washington River Protection Solutions (WRPS) is developing a Low-Activity Waste Pretreatment System (LAWPS) to provide low-activity waste (LAW) directly to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste Facility for immobilization. The pretreatment that will be conducted on tank waste supernate at the LAWPS facility entails filtration to remove entrained solids and cesium (Cs) ion exchange to remove Cs from the product sent to the WTP. Currently, spherical resorcinol-formaldehyde (sRF) resin (Microbeads AS, Skedsmokorset, Norway) is the Cs ion exchange resin of choice. Most work on Cs ion exchange efficacy in Hanford tank waste has been conducted at nominally 5 M sodium (Na). WRPS is examining the possibility of processing supernatant at high Na concentrations—up to 8 M Na—to maximize processing efficiency through the LAWPS. Minimal Cs ion exchange work has been conducted at 6 M and 8 M Na concentrations..

  4. Improving the Output Power Stability of a High Concentration Photovoltaic System with Supercapacitors: A Preliminary Evaluation

    Directory of Open Access Journals (Sweden)

    Yu-Pei Huang

    2015-01-01

    Full Text Available The output power of a high concentration photovoltaic (HCPV system is very sensitive to fluctuating tracking errors and weather patterns. To help compensate this shortcoming, supercapacitors have been successfully incorporated into photovoltaic systems to improve their output power stability. This study examined the output power stability improvement of an HCPV module with a supercapacitor integrated into its circuit. Furthermore, the equivalent model of the experimental circuit is presented and analyzed. Experimental results suggest that integrating a supercapacitor into an HCPV module could improve its output power stability and further extend its acceptance angle. This paper provides preliminary data of the improvement and its evaluation method, which could be utilized for further improvements to an HCPV system.

  5. Use of high concentration contrast media: principles and rationale--vascular district

    International Nuclear Information System (INIS)

    Fleischmann, Dominik.

    2003-01-01

    Optimal contrast medium delivery remains a crucial issue in CT angiography and it will become even more critical with continuously evolving, faster CT scanner technology. This review article first explains the fundamentals of arterial enhancement using mathematical models of early contrast medium dynamics. The relationship of contrast medium volume, injection flow rates and injection duration are explicitly illustrated. Next, current techniques of contrast medium application are reviewed, with particular attention to methods of accurate timing of the scanning delay (test-bolus and automated bolus triggering), tools for automated saline-flushing of the veins (double-syringe power injectors) and the use of high-concentration contrast medium. From there, rational CT angiographic injection protocols for a wide range of selectable acquisition times for 4-, 8- and 16-channel MDCT are proposed

  6. Concentration of 210Po in local foodstuffs grown nearby High Background Areas (HBRA)

    International Nuclear Information System (INIS)

    Kamesh Viswanathan, B.; Arunachalam, Kantha D.; Sathesh Kumar, A.; Jayakrishna, K.; Rao, D.D.

    2012-01-01

    210 Po is the decay product of natural radionuclide of 238 U series. The presence of a radionuclide migrates from soil > plant > food and ingested by the humans residing in the areas of syentite rocks nearby the High Background Radiation Area's (HBRA). The food samples were studied by Market Basket Study (MBS). The average concentration of 210 Po in foodstuffs like green leafy vegetables, other vegetables, roots and tubers; fruits, fish, other flesh foods, milk and cereals were 1671 ± 163.3, 28.2 ± 7.3, 320 ± 99, 53 ± 17.5, 251.5 ± 54.5, 37 ± 14.5, 16 ± 6 and 230 ± 75 mBq. Kg -1 fresh weight. (author)

  7. Water temperature and concentration measurements within the expanding blast wave of a high explosive

    International Nuclear Information System (INIS)

    Carney, J R; Lightstone, J M; Piecuch, S; Koch, J D

    2011-01-01

    We present an application of absorption spectroscopy to directly measure temperature and concentration histories of water vapor within the expansion of a high explosive detonation. While the approach of absorption spectroscopy is well established, the combination of a fast, near-infrared array, broadband light source, and rigid gauge allow the first application of time-resolved absorption measurements in an explosive environment. The instrument is demonstrated using pentaerythritol tetranitrate with a sampling rate of 20 kHz for 20 ms following detonation. Absorption by water vapor is measured between 1335 and 1380 nm. Water temperatures are determined by fitting experimental transmission spectra to a simulated database. Water mole fractions are deduced following the temperature assignment. The sources of uncertainty and their impact on the results are discussed. These measurements will aid the development of chemical-specific reaction models and the predictive capability in technical fields including combustion and detonation science

  8. Graphene oxide as efficient high-concentration formaldehyde scavenger and reutilization in supercapacitor.

    Science.gov (United States)

    Liang, Hongyu; Bu, Yongfeng; Zhang, Yutian; Zhang, Junyan

    2015-04-15

    Graphene oxide (GO) was investigated as a low-cost and high-efficient scavenger for high-concentration formaldehyde in alkali media. It showed very high removal capacity, 411 mg of formaldehyde per milligram of GO, and strong resistant to temperature changes. Additionally, the used GO can be easily renewed by a simple electrochemical method. By analyzing the componential and electrochemical characterizations of GO before and after use, the results showed that the degradation mechanism of formaldehyde is a collaborative process of chemical oxidation and physical adsorption, and the former dominates the degradation process. With the aid of oxygen-containing groups in GO, most formaldehyde can be easily oxidized by GO in alkaline media (this is equivalent to GO was reduced by formaldehyde). On the other hand, the used GO (reduced GO, noted as rGO) exhibits more ideal electronic double-layer capacitor (EDLC) feature than GO, along with higher rate capacitance (up to 136 F g(-1) at 50 A g(-1)). In short, GO is not only an efficient formaldehyde scavenger, but the used GO (rGO) can serve as promising electrical energy storage material. This study provides new insights for us to reutilize the discarded adsorbents generated from the environmental protection. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

    Energy Technology Data Exchange (ETDEWEB)

    Stechel, Ellen Beth; Ambrosini, Andrea; Hall, Aaron Christopher; Lambert, Timothy L.; Staiger, Chad Lynn; Bencomo, Marlene

    2010-09-01

    Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications.

  10. Inhibition of Coenzyme Qs Accumulation in Engineered Escherichia coli by High Concentration of Farnesyl Diphosphate

    Science.gov (United States)

    Samoudi, Mojtaba; Omid Yeganeh, Negar; Shahbani Zahiri, Hossein; Shariati, Parvin; Hajhosseini, Reza

    2015-01-01

    Background: Coenzyme Q 10 (CoQ 10 ) is an isoprenoid component used widely in nutraceutical industries. Farnesyl diphosphate synthase (FPPS) is a responsible enzyme for biosynthesis of farnesyl diphosphate (FPP), a key precursor for CoQs production. This research involved investigating the effect of FPPS over-expression on CoQs production in engineered CoQ 10 -producing Escherichia coli (E. coli). Methods: Two CoQ 10 -producing strains, as referred to E. coli Ba and E. coli Br, were transformed by the encoding gene for FPPS (ispA) under the control of either the trc or P BAD promoters. Results: Over-expression of ispA under the control of P BAD promoter led to a relative increase in CoQ 10 production only in recombinant E. coli Br although induction by arabinose resulted in partial reduction of CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains. Over-expression of ispA under the control of stronger trc promoter, however, led to a severe decrease in CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains, as reflected by reductions from 629±40 to 30±13 and 564±28 to 80±14 μg/g Dried Cell Weight (DCW), respectively. The results showed high level of FPP reduces endogenous CoQ 8 production as well and that CoQs are produced in a complimentary manner, as the increase in production of one decreases the production of the other. Conclusion: The reduction in CoQ 10 production can be a result of Dds inhibition by high FPP concentration. Therefore, more effort is needed to verify the role of intermediate metabolite concentration and to optimize production of CoQ 10 . PMID:26306151

  11. Quantified Hole Concentration in AlGaN Nanowires for High-Performance Ultraviolet Emitters

    KAUST Repository

    Zhao, Chao; Ebaid, Mohamed; Zhang, Huafan; Priante, Davide; Janjua, Bilal; Zhang, Daliang; Wei, Nini; Alhamoud, Abdullah; Shakfa, M. Khaled; Ng, Tien Khee; Ooi, Boon S.

    2018-01-01

    P-type doping in wide bandgap and new classes of ultra-wide bandgap materials has long been a scientific and engineering problem. The challenges arise from the large activation energy of dopants and high densities of dislocations in materials. We report here, a significantly enhanced p-type conduction using high-quality AlGaN nanowires. For the first time, the hole concentration in Mg-doped AlGaN nanowires is quantified. The incorporation of Mg into AlGaN was verified by correlation with photoluminescence and Raman measurements. The open-circuit potential measurements further confirmed the p-type conductivity; while Mott-Schottky experiments measured a hole concentration of 1.3×1019 cm-3. These results from photoelectrochemical measurements allow us to design prototype ultraviolet (UV) light-emitting diodes (LEDs) incorporating the AlGaN quantum-disks-in-nanowire and optimized p-type AlGaN contact layer for UV-transparency. The ~335-nm LEDs exhibited a low turn-on voltage of 5 V with a series resistance of 32 Ω, due to the efficient p-type doping of the AlGaN nanowires. The bias-dependent Raman measurements further revealed the negligible self-heating of devices. This study provides an attractive solution to evaluate electrical properties of AlGaN, which is applicable to other wide bandgap nanostructures. Our results are expected to open doors to new applications for wide and ultra-wide bandgap materials.

  12. Quantified Hole Concentration in AlGaN Nanowires for High-Performance Ultraviolet Emitters

    KAUST Repository

    Zhao, Chao

    2018-05-29

    P-type doping in wide bandgap and new classes of ultra-wide bandgap materials has long been a scientific and engineering problem. The challenges arise from the large activation energy of dopants and high densities of dislocations in materials. We report here, a significantly enhanced p-type conduction using high-quality AlGaN nanowires. For the first time, the hole concentration in Mg-doped AlGaN nanowires is quantified. The incorporation of Mg into AlGaN was verified by correlation with photoluminescence and Raman measurements. The open-circuit potential measurements further confirmed the p-type conductivity; while Mott-Schottky experiments measured a hole concentration of 1.3×1019 cm-3. These results from photoelectrochemical measurements allow us to design prototype ultraviolet (UV) light-emitting diodes (LEDs) incorporating the AlGaN quantum-disks-in-nanowire and optimized p-type AlGaN contact layer for UV-transparency. The ~335-nm LEDs exhibited a low turn-on voltage of 5 V with a series resistance of 32 Ω, due to the efficient p-type doping of the AlGaN nanowires. The bias-dependent Raman measurements further revealed the negligible self-heating of devices. This study provides an attractive solution to evaluate electrical properties of AlGaN, which is applicable to other wide bandgap nanostructures. Our results are expected to open doors to new applications for wide and ultra-wide bandgap materials.

  13. High concentrations of manganese and sulfur in deposits on Murray Ridge, Endeavour Crater, Mars

    Science.gov (United States)

    Arvidson, Raymond E.; Squyres, Steven W.; Morris, Richard V.; Knoll, Andrew H.; Gellert, Ralf; Clark, Benton C.; Catalano, Jeffrey G.; Jolliff, Bradley L.; McLennan, Scott M.; Herkenhoff, Kenneth E.; VanBommel, Scott; Mittelfehldt, David W.; Grotzinger, John P.; Guinness, Edward A.; Johnson, Jeffrey R.; Bell, James F.; Farrand, William H.; Stein, Nathan; Fox, Valerie K.; Golombek, Matthew P.; Hinkle, Margaret A. G.; Calvin, Wendy M.; de Souza, Paulo A.

    2016-01-01

    Mars Reconnaissance Orbiter HiRISE images and Opportunity rover observations of the ~22 km wide Noachian age Endeavour Crater on Mars show that the rim and surrounding terrains were densely fractured during the impact crater-forming event. Fractures have also propagated upward into the overlying Burns formation sandstones. Opportunity’s observations show that the western crater rim segment, called Murray Ridge, is composed of impact breccias with basaltic compositions, as well as occasional fracture-filling calcium sulfate veins. Cook Haven, a gentle depression on Murray Ridge, and the site where Opportunity spent its sixth winter, exposes highly fractured, recessive outcrops that have relatively high concentrations of S and Cl, consistent with modest aqueous alteration. Opportunity’s rover wheels serendipitously excavated and overturned several small rocks from a Cook Haven fracture zone. Extensive measurement campaigns were conducted on two of them: Pinnacle Island and Stuart Island. These rocks have the highest concentrations of Mn and S measured to date by Opportunity and occur as a relatively bright sulfate-rich coating on basaltic rock, capped by a thin deposit of one or more dark Mn oxide phases intermixed with sulfate minerals. We infer from these unique Pinnacle Island and Stuart Island rock measurements that subsurface precipitation of sulfate-dominated coatings was followed by an interval of partial dissolution and reaction with one or more strong oxidants (e.g., O2) to produce the Mn oxide mineral(s) intermixed with sulfate-rich salt coatings. In contrast to arid regions on Earth, where Mn oxides are widely incorporated into coatings on surface rocks, our results demonstrate that on Mars the most likely place to deposit and preserve Mn oxides was in fracture zones where migrating fluids intersected surface oxidants, forming precipitates shielded from subsequent physical erosion.

  14. Formation of calcium phosphates by vapour diffusion in highly concentrated ionic micro-droplets

    Energy Technology Data Exchange (ETDEWEB)

    Iafisco, M. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy); Universita del Piemonte Orientale, Dipartimento di Scienze Mediche, Via Solaroli 4, 28100 Novara (Italy); Delgado-Lopez, J.M.; Gomez-Morales, J.; Hernandez-Hernandez, M.A.; Rodriguez-Ruiz, I. [Laboratorio de Estudios Cristalograficos, IACT CSIC-UGR, Edificio Lopez Neyra, Avenida del Conocimiento, s/n 18100 Armilla (Spain); Roveri, N. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy)

    2011-08-15

    In this work we have used the sitting drop vapour diffusion technique, employing the ''crystallization mushroom '' to analyze the evolution of calcium phosphate crystallization in micro-droplets containing high initial concentrations of Ca{sup 2+} and HPO{sub 4}{sup 2-}. The decomposition of NH{sub 4}HCO{sub 3} solution produces vapours of NH{sub 3} and CO{sub 2} which diffuse through the droplets containing an aqueous solution of Ca(CH{sub 3}COO){sub 2} and (NH{sub 4}){sub 2}HPO{sub 4}. The result is the increase of pH by means of the diffusion of NH{sub 3} gas and the doping of the calcium phosphate with CO{sub 3}{sup 2-} ions by means of the diffusion of CO{sub 2} gas. The pH of the crystallization process is monitored and the precipitates at different times are characterized by XRD, FTIR, TGA, SEM and TEM techniques. The slow increase of pH and the high concentration of Ca{sup 2+} and HPO{sub 4}{sup 2-} in the droplets induce the crystallization of three calcium phosphate phases: dicalcium phosphate dihydrate (DCPD, brushite), octacalcium phosphate (OCP) and carbonate-hydroxyapatite (HA). The amount of HA nanocrystals with needle-like morphology and dimensions of about 100 nm, closely resembling the inorganic phase of bones, gradually increases, with the precipitation time up to 7 days, whereas the amount of DCPD, growing along the b axis, increases up to 3 days. Then, DCDP crystals start to hydrolyze yielding OCP nanoribbons and HA nanocrystals. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Microwave enhanced Fenton-like process for the treatment of high concentration pharmaceutical wastewater

    International Nuclear Information System (INIS)

    Yang Yu; Wang Peng; Shi Shujie; Liu Yuan

    2009-01-01

    This paper explored a novel process for wastewater treatment, i.e. microwave enhanced Fenton-like process. This novel process was introduced to treat high concentration pharmaceutical wastewater with initial COD loading of 49,912.5 mg L -1 . Operating parameters were investigated and the optimal condition included as follows: microwave power was 300 W, radiation time was 6 min, initial pH was 4.42, H 2 O 2 dosage was 1300 mg L -1 and Fe 2 (SO 4 ) 3 dosage was 4900 mg L -1 , respectively. Within the present experimental condition used, the COD removal and UV 254 removal reached to 57.53% and 55.06%, respectively, and BOD 5 /COD was enhanced from 0.165 to 0.470. The variation of molecular weight distribution indicated that both macromolecular substances and micromolecular substances were eliminated quite well. The structure of flocs revealed that one ferric hydrated ion seemed to connect with another ferric hydrated ion and/or organic compound molecule to form large-scale particles by means of van der waals force and/or hydrogen bond. Subsequently, these particles aggregated to form flocs and settled down. Comparing with traditional Fenton-like reaction and conventional heating assisted Fenton-like reaction, microwave enhanced Fenton-like process displayed superior treatment efficiency. Microwave was in favor of improving the degradation efficiency, the settling quality of sludge, as well as reducing the yield of sludge and enhancing the biodegradability of effluent. Microwave enhanced Fenton-like process is believed to be a promising treatment technology for high concentration and biorefractory wastewater.

  16. Reaction monitoring using hyperpolarized NMR with scaling of heteronuclear couplings by optimal tracking

    Science.gov (United States)

    Zhang, Guannan; Schilling, Franz; Glaser, Steffen J.; Hilty, Christian

    2016-11-01

    Off-resonance decoupling using the method of Scaling of Heteronuclear Couplings by Optimal Tracking (SHOT) enables determination of heteronuclear correlations of chemical shifts in single scan NMR spectra. Through modulation of J-coupling evolution by shaped radio frequency pulses, off resonance decoupling using SHOT pulses causes a user-defined dependence of the observed J-splitting, such as the splitting of 13C peaks, on the chemical shift offset of coupled nuclei, such as 1H. Because a decoupling experiment requires only a single scan, this method is suitable for characterizing on-going chemical reactions using hyperpolarization by dissolution dynamic nuclear polarization (D-DNP). We demonstrate the calculation of [13C, 1H] chemical shift correlations of the carbanionic active sites from hyperpolarized styrene polymerized using sodium naphthalene as an initiator. While off resonance decoupling by SHOT pulses does not enhance the resolution in the same way as a 2D NMR spectrum would, the ability to obtain the correlations in single scans makes this method ideal for determination of chemical shifts in on-going reactions on the second time scale. In addition, we present a novel SHOT pulse that allows to scale J-splittings 50% larger than the respective J-coupling constant. This feature can be used to enhance the resolution of the indirectly detected chemical shift and reduce peak overlap, as demonstrated in a model reaction between p-anisaldehyde and isobutylamine. For both pulses, the accuracy is evaluated under changing signal-to-noise ratios (SNR) of the peaks from reactants and reaction products, with an overall standard deviation of chemical shift differences compared to reference spectra of 0.02 ppm when measured on a 400 MHz NMR spectrometer. Notably, the appearance of decoupling side-bands, which scale with peak intensity, appears to be of secondary importance.

  17. Cell-Type Specific Development of the Hyperpolarization-Activated Current, Ih, in Prefrontal Cortical Neurons

    Directory of Open Access Journals (Sweden)

    Sha-Sha Yang

    2018-05-01

    Full Text Available H-current, also known as hyperpolarization-activated current (Ih, is an inward current generated by the hyperpolarization-activated cyclic nucleotide-gated (HCN cation channels. Ih plays an essential role in regulating neuronal properties, synaptic integration and plasticity, and synchronous activity in the brain. As these biological factors change across development, the brain undergoes varying levels of vulnerability to disorders like schizophrenia that disrupt prefrontal cortex (PFC-dependent function. However, developmental changes in Ih in PFC neurons remains untested. Here, we examine Ih in pyramidal neurons vs. gamma-aminobutyric acid (GABAergic parvalbumin-expressing (PV+ interneurons in developing mouse PFC. Our findings show that the amplitudes of Ih in these cell types are identical during the juvenile period but differ at later time points. In pyramidal neurons, Ih amplitude significantly increases from juvenile to adolescence and follows a similar trend into adulthood. In contrast, the amplitude of Ih in PV+ interneurons decreases from juvenile to adolescence, and does not change from adolescence to adulthood. Moreover, the kinetics of HCN channels in pyramidal neurons is significantly slower than in PV+ interneurons, with a gradual decrease in pyramidal neurons and a gradual increase in PV+ cells across development. Our study reveals distinct developmental trajectories of Ih in pyramidal neurons and PV+ interneurons. The cell-type specific alteration of Ih during the critical period from juvenile to adolescence reflects the contribution of Ih to the maturation of the PFC and PFC-dependent function. These findings are essential for a better understanding of normal PFC function, and for elucidating Ih’s crucial role in the pathophysiology of neurodevelopmental disorders.

  18. ACh-induced hyperpolarization and decreased resistance in mammalian type II vestibular hair cells.

    Science.gov (United States)

    Poppi, Lauren A; Tabatabaee, Hessam; Drury, Hannah R; Jobling, Phillip; Callister, Robert J; Migliaccio, Americo A; Jordan, Paivi M; Holt, Joseph C; Rabbitt, Richard D; Lim, Rebecca; Brichta, Alan M

    2018-01-01

    In the mammalian vestibular periphery, electrical activation of the efferent vestibular system (EVS) has two effects on afferent activity: 1) it increases background afferent discharge and 2) decreases afferent sensitivity to rotational stimuli. Although the cellular mechanisms underlying these two contrasting afferent responses remain obscure, we postulated that the reduction in afferent sensitivity was attributed, in part, to the activation of α9- containing nicotinic acetylcholine (ACh) receptors (α9*nAChRs) and small-conductance potassium channels (SK) in vestibular type II hair cells, as demonstrated in the peripheral vestibular system of other vertebrates. To test this hypothesis, we examined the effects of the predominant EVS neurotransmitter ACh on vestibular type II hair cells from wild-type (wt) and α9-subunit nAChR knockout (α9 -/- ) mice. Immunostaining for choline acetyltransferase revealed there were no obvious gross morphological differences in the peripheral EVS innervation among any of these strains. ACh application onto wt type II hair cells, at resting potentials, produced a fast inward current followed by a slower outward current, resulting in membrane hyperpolarization and decreased membrane resistance. Hyperpolarization and decreased resistance were due to gating of SK channels. Consistent with activation of α9*nAChRs and SK channels, these ACh-sensitive currents were antagonized by the α9*nAChR blocker strychnine and SK blockers apamin and tamapin. Type II hair cells from α9 -/- mice, however, failed to respond to ACh at all. These results confirm the critical importance of α9nAChRs in efferent modulation of mammalian type II vestibular hair cells. Application of exogenous ACh reduces electrical impedance, thereby decreasing type II hair cell sensitivity. NEW & NOTEWORTHY Expression of α9 nicotinic subunit was crucial for fast cholinergic modulation of mammalian vestibular type II hair cells. These findings show a multifaceted

  19. Hyperpolarized 3He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Mathew, Lindsay; Kirby, Miranda; Etemad-Rezai, Roya; Wheatley, Andrew; McCormack, David G.; Parraga, Grace

    2011-01-01

    Rationale and objectives: Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 ( 3 He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for 3 He MRI in detecting the lung structural and functional COPD phenotypes. Materials and methods: We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, 1 H MRI and hyperpolarized 3 He MRI at 3.0 T. 3 He ventilation defect percent (VDP) was generated from 3 He static ventilation images and 1 H thoracic images and the 3 He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI. Results: Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant 3 He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group). Conclusion: In this small pilot study, a preliminary analysis shows the potential for 3 He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.

  20. Mis-estimation and bias of hyperpolarized apparent diffusion coefficient measurements due to slice profile effects.

    Science.gov (United States)

    Gordon, Jeremy W; Milshteyn, Eugene; Marco-Rius, Irene; Ohliger, Michael; Vigneron, Daniel B; Larson, Peder E Z

    2017-09-01

    The purpose of this work was to explore the impact of slice profile effects on apparent diffusion coefficient (ADC) mapping of hyperpolarized (HP) substrates. Slice profile effects were simulated using a Gaussian radiofrequency (RF) pulse with a variety of flip angle schedules and b-value ordering schemes. A long T 1 water phantom was used to validate the simulation results, and ADC mapping of HP [ 13 C, 15 N 2 ]urea was performed on the murine liver to assess these effects in vivo. Slice profile effects result in excess signal after repeated RF pulses, causing bias in HP measurements. The largest error occurs for metabolites with small ADCs, resulting in up to 10-fold overestimation for metabolites that are in more-restricted environments. A mixed b-value scheme substantially reduces this bias, whereas scaling the slice-select gradient can mitigate it completely. In vivo, the liver ADC of hyperpolarized [ 13 C, 15 N 2 ]urea is nearly 70% lower (0.99 ± 0.22 vs 1.69 ± 0.21 × 10 -3 mm 2 /s) when slice-select gradient scaling is used. Slice profile effects can lead to bias in HP ADC measurements. A mixed b-value ordering scheme can reduce this bias compared to sequential b-value ordering. Slice-select gradient scaling can also correct for this deviation, minimizing bias and providing more-precise ADC measurements of HP substrates. Magn Reson Med 78:1087-1092, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  1. Higs-instrument: design and demonstration of a high performance gas concentration imager

    Science.gov (United States)

    Verlaan, A. L.; Klop, W. A.; Visser, H.; van Brug, H.; Human, J.

    2017-09-01

    Climate change and environmental conditions are high on the political agenda of international governments. Laws and regulations are being setup all around the world to improve the air quality and to reduce the impact. The growth of a number of trace gasses, including CO2, Methane and NOx are especially interesting due to their environmental impact. The regulations made are being based on both models and measurements of the trend of those trace gases over the years. Now the regulations are in place also enforcement and therewith measurements become more and more important. Instruments enabling high spectral and spatial resolution as well as high accurate measurements of trace gases are required to deliver the necessary inputs. Nowadays those measurements are usually performed by space based spectrometers. The requirement for high spectral resolution and measurement accuracy significantly increases the size of the instruments. As a result the instrument and satellite becomes very expensive to develop and to launch. Specialized instruments with a small volume and the required performance will offer significant advantages in both cost and performance. Huib's Innovative Gas Sensor (HIGS, named after its inventor Huib Visser), currently being developed at TNO is an instrument that achieves exactly that. Designed to measure only a single gas concentration, opposed to deriving it from a spectrum, it achieves high performance within a small design volume. The instrument enables instantaneous imaging of the gas distribution of the selected gas. An instrument demonstrator has been developed for NO2 detection. Laboratory measurements proved the measurement technique to be successful. An on-sky measurement campaign is in preparation. This paper addresses both the instrument design as well as the demonstrated performances.

  2. Economic Justification of Concentrating Solar Power in High Renewable Energy Penetrated Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, Brian S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kroposki, Benjamin D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Du, Ershun [Tsinghua University; Zhang, Ning [Tsinghua University; Kang, Chongqing [Tsinghua University; Xia, Qing [Tsinghua University

    2018-04-24

    Concentrating solar power (CSP) plants are able to provide both renewable energy and operational flexibility at the same time due to its thermal energy storage (TES). It is ideal generation to power systems lacking in flexibility to accommodate variable renewable energy (VRE) generation such as wind power and photovoltaics. However, its investment cost currently is too high to justify its benefit in terms of providing renewable energy only. In this paper we evaluate the economic benefit of CSP in high renewable energy penetrated power systems from two aspects: generating renewable energy and providing operational flexibility to help accommodating VRE. In order to keep the same renewable energy penetration level during evaluation, we compare the economic costs between the system with a high share of VRE and another in which some part of the VRE generation is replaced by CSP generation. The generation cost of a power system is analyzed through chronological operation simulation over a whole year. The benefit of CSP is quantified into two parts: (1) energy benefit - the saving investment of substituted VRE generation and (2) flexibility benefit - the reduction in operating cost due to substituting VRE with CSP. The break-even investment cost of CSP is further discussed. The methodology is tested on a modified IEEE RTS-79 system. The economic justifications of CSP are demonstrated in two practical provincial power systems with high penetration of renewable energy in northwestern China, Qinghai and Gansu, where the former province has massive inflexible thermal power plants but later one has high share of flexible hydro power. The results suggest that the CSP is more beneficial in Gansu system than in Qinghai. The levelized benefit of CSP, including both energy benefit and flexibility benefit, is about 0.177-0.191 $/kWh in Qinghai and about 0.238-0.300 $/kWh in Gansu, when replacing 5-20% VRE generation with CSP generation.

  3. Near-bed observations of high-concentration sediment transport in the Changjiang Estuary

    Science.gov (United States)

    Zhou, Z.; Ge, J.; Ding, P.

    2017-12-01

    The North Passage, the core of turbidity maximum in the Changjiang Estuary, is now under the strong sedimentation due to the abundant sediment supply from the upstream Changjiang River and the river-tide interacted dynamics. Recent studies suggested that strong siltation could be attributed to bottom high-concentration sediment transport, which however is very difficult to be detected and observed by vessel-anchored survey methods. To better understand the mechanisms of sediment transport and deposition in the channel region of the North Passage and its adjacent areas, we conducted continuous field observations which covered spring and neap tide period in the wintertime of 2016, the summertime of 2015 and 2017, focusing on near-bottom sediment transport. Tripods mounted with multiple instruments, including up-looking and down-looking Acoustic Doppler Current Profilers(ADCP), Vector Current Meter(ADV), Optical Backscatter Sensor(OBS), ASM, ALEC and RBR were used to observe the near-bottom physical process and its induced sediment dynamics. Results of these observations clearly described the current-wave-sediment interaction, which produced different patterns of bottom mud suspension at different tripods. Both hydrodynamic features and suspended sediment showed variations between spring and neap tide. Taking data of 2016 as an example, averaged suspended sediment concentration(SSC) at two tripods was 1.52 g/L and 2.13 g/L during the neap tide, 4.51 g/L and 5.75 g/L with the peak value reaching 25 g/L during the spring tide. At the tripod which was closer to the channel region, three peaks of SSC during the spring tide occurred near the flood slack with notable salinity increase, indicating the impact of saltwater intrusion on the bottom hydrodynamics. The results showed the occurrence of high-concentration suspended sediment was probably related to combined effects of bottom salinity intrusion, turbulent kinetic energy(TKE) and local stratification due to density

  4. Plasma capric acid concentrations in healthy subjects determined by high-performance liquid chromatography.

    Science.gov (United States)

    Shrestha, Rojeet; Hui, Shu-Ping; Imai, Hiromitsu; Hashimoto, Satoru; Uemura, Naoto; Takeda, Seiji; Fuda, Hirotoshi; Suzuki, Akira; Yamaguchi, Satoshi; Hirano, Ken-Ichi; Chiba, Hitoshi

    2015-09-01

    Capric acid (FA10:0, decanoic acid) is a medium-chain fatty acid abundant in tropical oils such as coconut oil, whereas small amounts are present in milk of goat, cow, and human. Orally ingested FA10:0 is transported to the liver and quickly burnt within it. Only few reports are available for FA10:0 concentrations in human plasma. Fasting (n = 5, male/female = 3/2, age 31 ± 9.3 years old) and non-fasting (n = 106, male/female = 44/62, age 21.9 ± 3.2 years old) blood samples were collected from apparently healthy Japanese volunteers. The total FA10:0 in the plasma were measured by high-performance liquid chromatography after derivatization with 2-nitrophenylhydrazine followed by UV detection. Inter and intra-assay coefficient of variation of FA10:0 assay at three different concentrations ranged in 1.7-3.9 and 1.3-5.4%, respectively, with an analytical recovery of 95.2-104.0%. FA10:0 concentration was below detection limit (0.1 µmol/L) in each fasting human plasma. FA10:0 was not detected in 50 (47.2%) of 106 non-fasting blood samples, while 29 (27.4%) plasma samples contained FA10:0 less than or equal to 0.5 µmol/L (0.4 ± 0.1), and 27 (25.5%) contained it at more than 0.5 µmol/L (0.9 ± 0.3). A half of the non-fasting plasma samples contained detectable FA10:0. This simple, precise, and accurate high-performance liquid chromatography method might be useful for monitoring plasma FA10:0 during medium-chain triglycerides therapy. © The Author(s) 2015.

  5. Assessment of high precision, high accuracy Inductively Coupled Plasma-Optical Emission Spectroscopy to obtain concentration uncertainties less than 0.2% with variable matrix concentrations

    International Nuclear Information System (INIS)

    Rabb, Savelas A.; Olesik, John W.

    2008-01-01

    The ability to obtain high precision, high accuracy measurements in samples with complex matrices using High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy (HP-ICP-OES) was investigated. The Common Analyte Internal Standard (CAIS) procedure was incorporated into the High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy method to correct for matrix-induced changes in emission intensity ratios. Matrix matching and standard addition approaches to minimize matrix-induced errors when using High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy were also assessed. The High Performance Inductively Coupled Plasma-Optical Emission Spectroscopy method was tested with synthetic solutions in a variety of matrices, alloy standard reference materials and geological reference materials

  6. Development of Concentration and Calcination Technology For High Level Liquid Waste

    International Nuclear Information System (INIS)

    Pande, D.P.

    2006-01-01

    The concentrated medium and high-level liquid radio chemicals effluents contain nitric acid, water along with the dissolved chemicals including the nitrates of the radio nuclides. High level liquid waste contain mainly nitrates of cesium, strontium, cerium, zirconium, chromium, barium, calcium, cobalt, copper, pickle, iron etc. and other fission products. This concentrated solution requires further evaporation, dehydration, drying and decomposition in temperature range of 150 to 700 deg. C. The addition of the calcined solids in vitrification pot, instead of liquid feed, helps to avoid low temperature zone because the vaporization of the liquid and decomposition of nitrates do not take place inside the melter. In our work Differential and thermo gravimetric studies has been carried out in the various stages of thermal treatment including drying, dehydration and conversion to oxide forms. Experimental studies were done to characterize the chemicals present in high-level radioactive waste. A Rotary Ball Kiln Calciner was used for development of the process because this is amenable for continuous operation and moderately good heat transfer can be achieved inside the kiln. This also has minimum secondary waste and off gases generation. The Rotary Ball Kiln Calciner Demonstration facility system was designed and installed for the demonstration of calcination process. The Rotary Ball Kiln Calciner is a slowly rotating slightly inclined horizontal tube that is externally heated by means of electric resistance heating. The liquid feed is sprayed onto the moving bed of metal balls in a slowly rotating calciner by a peristaltic type-metering pump. The vaporization of the liquid occurs in the pre-calcination zone due to counter current flow of hot gases. The dehydration and denitration of the solids occurs in the calcination zone, which is externally heated by electrical furnace. The calcined powder is cooled in the post calcination portion. It has been demonstrated that the

  7. Response of plants to high concentrations of uranium stress and the screening of remediation plants

    International Nuclear Information System (INIS)

    Tang Yongjin; Luo Xuegang; Zeng Feng; Jiang Shijie

    2013-01-01

    Studies of the resistance and accumulation ability of different plant species to uranium (U) has important influence on the bioremediation of U contaminated soil. The resistance and enrichment ability of high concentrations of U (500 mg · kg"-"1 soil) in fourteen plant species were investigated and evaluated in this study in order to screen remediation plants for governance soil U contamination. The results showed that: (1) high concentrations of U stress had different effects on the emergence and survival of the different plants. The seed emergence of Hibiscus esculentus was reduced by 2/3, but the seed emergence of Gynura cusimbua (D. Don) S. Moore, Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not reduced. Under the contaminated soil, all the sesamum indicum died within a month after the emergence and the survival number of Amaranth and Iresine herbstii 'Aureo-reticulata' reduced by about 80%. But the survival number of Alternanthera philoxeroides (Mart.) Griseb., Chenopodium album L. and Phaseolus vulgaris var. humilis Alef were not influenced. (2) The biomass of the plants would be reduced by 8-99% in the uranium-contaminated soil. The anti-stress ability of Phaseolus vulgaris var. humilis Alef was the strongest in the fourteen plants, and Cucurbita pepo L., Sorghumbicolor (L.) Moench, Ipomoea aquatica Forsk, Helianthus annuus, Chenopodium album L. and Alternanthera philoxeroides (Mart.) Griseb. showed some the anti-stress ability. (3) Significant differences were found in the capacity of plants to absorb uranium between under high-uranium contaminated soil and under the non-uranium contaminated soil were. The plants with higher uranium content in thenon-contaminated soil were Gomphrena globosa, and Cucurbita pepo L., which were 2.249 mg · kg"-"1 DW and 1.620 mg · kg"-"1 DW, respectively. But the plants with higher uranium content in the high uranium contaminated soil were Cichorium intybus L., Amaranth and Ipomoea aquatica Forsk, which

  8. The effect of extremely high glucose concentrations on 21 routine chemistry and thyroid Abbott assays: interference study

    OpenAIRE

    ?uhadar, Serap; K?seo?lu, Mehmet; ?inpolat, Yasemin; Bu?dayc?, G?ler; Usta, Murat; Semerci, Tuna

    2016-01-01

    Abstract Introduction: Extremely high glucose concentrations have been shown to interfere with creatinine assays especially with Jaffe method in peritoneal dialysate. Because diabetes is the fastest growing chronic disease in the world, laboratories study with varying glucose concentrations. We investigated whether different levels of glucose spiked in serum interfere with 21 routine chemistry and thyroid assays at glucose concentrations between 17-51 mmol/L. Materials and methods: Base...

  9. A strategy for urban outdoor production of high-concentration algal biomass for green biorefining.

    Science.gov (United States)

    Lim, Chun Yong; Chen, Chia-Lung; Wang, Jing-Yuan

    2013-05-01

    The present study was to investigate the feasibility of carrying out effective microalgae cultivation and high-rate tertiary wastewater treatment simultaneously in a vertical sequencing batch photobioreactor with small areal footprint, suitable for sustainable urban microalgae production. For 15 consecutive days, Chlorella sorokiniana was cultivated in synthetic wastewater under various trophic conditions. A cycle of 12-h heterotrophic: 12-h mixotrophic condition produced 0.98 g l(-1) d(-1) of algal biomass in tandem with a 94.7% removal of 254.4 mg l(-1) C-acetate, a 100% removal of 84.7 mg l(-1) N-NH4 and a removal of 15.0 mg l(-1) P-PO4. The cells were harvested via cost-effective chitosan flocculation with multiple dosing (3 times) applying established chitosan:cell ratio (1:300 w/w) and pH control (6.3-6.8). Reproducible flocculation efficiencies of greater than 99% and high-concentration algal broths (>20% solids) were achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. User characteristics and effect profile of Butane Hash Oil: An extremely high-potency cannabis concentrate.

    Science.gov (United States)

    Chan, Gary C K; Hall, Wayne; Freeman, Tom P; Ferris, Jason; Kelly, Adrian B; Winstock, Adam

    2017-09-01

    Recent reports suggest an increase in use of extremely potent cannabis concentrates such as Butane Hash Oil (BHO) in some developed countries. The aims of this study were to examine the characteristics of BHO users and the effect profiles of BHO. Anonymous online survey in over 20 countries in 2014 and 2015. Participants aged 18 years or older were recruited through onward promotion and online social networks. The overall sample size was 181,870. In this sample, 46% (N=83,867) reported using some form of cannabis in the past year, and 3% reported BHO use (n=5922). Participants reported their use of 7 types of cannabis in the past 12 months, the source of their cannabis, reasons for use, use of other illegal substances, and lifetime diagnosis for depression, anxiety and psychosis. Participants were asked to rate subjective effects of BHO and high potency herbal cannabis. Participants who reported a lifetime diagnosis of depression (OR=1.15, p=0.003), anxiety (OR=1.72, pcannabis. BHO users also reported stronger negative effects and less positive effects when using BHO than high potency herbal cannabis (pcannabis. Copyright © 2017. Published by Elsevier B.V.

  11. Improvement in mechanical properties of high concentration particle doped thermoset composites

    International Nuclear Information System (INIS)

    Ahmed, N.

    2009-01-01

    The paper relates to high concentration particle doped composites based on thermosetting polymer systems in which the sequential addition of particles of certain size distribution is followed by curing and casting of the slurry to form a thermoset composite. Conventionally, at a threshold of beyond 90% of particles by weight of the polymer using triglyceride, the mechanical properties of the composite exhibit a sharp decline. The present research mitigates this behavior by incorporating a unique combination of cross-linking agents in the base polymer to impart exceptional mechanical properties to the composite. More specifically, the base polymer consists of butadiene, with triglyceride as cross-linking agent together with hydroxy-alkane as the chain extension precursors, when tune to the appropriate level of hard segment ratio in the polymer. An added advantage according to the present work resides in the analytical nature of butadiene pre-polymer as opposed to natural product; traditional composites based on natural sources are hampered by their inconsistent chemical composition and poor shelf life in the fabricated composite. The thermoset composite according the present research exhibits superior tensile strength (200-300 psi) properties using particle loading as high as 92% by weight of the fabricated composite as measured on a Tinius Olsen machine. Dynamic Mechanical Testing reveals interesting combination of storage and loss moduli in the fabricated specimens as a function of optimizing the thermal response of the viscoelastic composite to imposed vibration loading. (author)

  12. Process design of high-concentration benzimidazole wastewater treatment based on the molecular structure of contaminants.

    Science.gov (United States)

    Li, Chenru; Qian, Kun; Liu, Qinyao; Zhang, Qianyi; Yao, Chen; Song, Wei; Wang, Yihong

    2018-04-01

    Benzimidazole is an important intermediate in industry and it is usually difficult to be degraded by many treatment technologies. Looking for a highly effective, environment-friendly degradation process for benzimidazole wastewater is of great significance to reduce pollution. Based on the structure of contaminants, the micro-electrolysis (ME) coupled with the Fenton technique was chosen to degrade the industrial benzimidazole wastewater. Special feeding was applied to maintain the suitable hydrogen peroxide (H 2 O 2 ) concentration to produce the hydroxyl radicals (•OH) as much as possible and protect •OH from being quenched by excess H 2 O 2 according to the reaction mechanism. The results showed that this combined technique was highly efficient to decompose benzimidazole compounds. More chemical oxygen demand (COD) could be reduced when flow control was used, compared to the flow not being controlled. The COD removal rate could reach 85.2% at optimal parameters. Then the effluent of this process was combined with the existing biochemical system for further degradation. The studies of Ultraviolet Spectrophotometry, Fourier Transform Infrared Spectroscopy and Liquid Chromatography Mass Spectrometry showed that both 2-(a-Hydroxyethyl) benzimidazole and 2-Acetylbenzimidazole were decomposed to the isopropanolamine and aniline after the ME treatment; then the intermediates were oxidized into oxalic acid after the Fenton reaction.

  13. Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

    Energy Technology Data Exchange (ETDEWEB)

    Keskinen, J; Hautanen, J; Laitinen, A [Tampere Univ. of Technology (Finland). Physics

    1997-10-01

    The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

  14. [Geographic distribution and exposure population of drinking water with high concentration of arsenic in China].

    Science.gov (United States)

    Zhang, L; Chen, C

    1997-09-01

    According to the data obtained from the "National Survey on Drinking Water Quality and Waterborne Diseases", the geographic distribution and exposure population of high arsenic drinking water were reported. From the data of more than 28,800 water samples, we found 9.02 million people drinking the water with As concentration of 0.030-0.049 mg/L, 3.34 million people having their water of 0.050-0.099 mg/L and 2.29 million people having water of > 0.1 mg/L. A total of 14.6 million people, about 1.5% of the surveyed population was exposed to As (> 0.030 mg/L) from drinking water. 80% of high-As-drinking water was groundwater. The situation of As in drinking water in provinces, autonomous regions and municipalities were listed. The locations of sampling site where water As exceeded the national standard for drinking water were illustrated.

  15. High Concentration of Zinc in Sub-retinal Pigment Epithelial Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Lengyel,I.; Flinn, J.; Peto, T.; Linkous, D.; Cano, K.; Bird, A.; Lanzirotti, A.; Frederickson, C.; van Kuijk, F.

    2007-01-01

    One of the hallmarks of age-related macular degeneration (AMD), the leading cause of blindness in the elderly in Western societies, is the accumulation of sub-retinal pigment epithelial deposits (sub-RPE deposits), including drusen and basal laminar deposits, in Bruch's membrane (BM). The nature and the underlying mechanisms of this deposit formation are not fully understood. Because we know that zinc contributes to deposit formation in neurodegenerative diseases, we tested the hypothesis that zinc might be involved in deposit formation in AMD. Using zinc specific fluorescent probes and microprobe synchrotron X-ray fluorescence we showed that sub-RPE deposits in post-mortem human tissues contain unexpectedly high concentrations of zinc, including abundant bio-available (ionic and/or loosely protein bound) ions. Zinc accumulation was especially high in the maculae of eyes with AMD. Internal deposit structures are especially enriched in bio-available zinc. Based on the evidence provided here we suggest that zinc plays a role in sub-RPE deposit formation in the aging human eye and possibly also in the development and/or progression of AMD.

  16. High Concentration of Zinc in Sub-retinal Pigment Epithelial Deposits

    International Nuclear Information System (INIS)

    Lengyel, I.; Flinn, J.; Peto, T.; Linkous, D.; Cano, K.; Bird, A.; Lanzirotti, A.; Frederickson, C.; van Kuijk, F.

    2007-01-01

    One of the hallmarks of age-related macular degeneration (AMD), the leading cause of blindness in the elderly in Western societies, is the accumulation of sub-retinal pigment epithelial deposits (sub-RPE deposits), including drusen and basal laminar deposits, in Bruch's membrane (BM). The nature and the underlying mechanisms of this deposit formation are not fully understood. Because we know that zinc contributes to deposit formation in neurodegenerative diseases, we tested the hypothesis that zinc might be involved in deposit formation in AMD. Using zinc specific fluorescent probes and microprobe synchrotron X-ray fluorescence we showed that sub-RPE deposits in post-mortem human tissues contain unexpectedly high concentrations of zinc, including abundant bio-available (ionic and/or loosely protein bound) ions. Zinc accumulation was especially high in the maculae of eyes with AMD. Internal deposit structures are especially enriched in bio-available zinc. Based on the evidence provided here we suggest that zinc plays a role in sub-RPE deposit formation in the aging human eye and possibly also in the development and/or progression of AMD

  17. G eobacter sp. SD-1 with enhanced electrochemical activity in high-salt concentration solutions

    KAUST Repository

    Sun, Dan; Call, Douglas; Wang, Aijie; Cheng, Shaoan; Logan, Bruce E.

    2014-01-01

    © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd. Summary: An isolate, designated strain SD-1, was obtained from a biofilm dominated by Geobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD-1 was compared with type strains, G.sulfurreducensPCA and Geobacter metallireducensGS-15, and a mixed culture in microbial electrolysis cells. SD-1 produced a maximum current density of 290±29Am-3 in a high-concentration phosphate buffer solution (PBS-H, 200mM). This current density was significantly higher than that produced by the mixed culture (189±44Am-3) or the type strains (<70Am-3). In a highly saline water (SW; 50mM PBS and 650mM NaCl), current by SD-1 (158±4Am-3) was reduced by 28% compared with 50mM PBS (220±4Am-3), but it was still higher than that of the mixed culture (147±19Am-3), and strains PCA and GS-15 did not produce any current. Electrochemical tests showed that the improved performance of SD-1 was due to its lower charge transfer resistance and more negative potentials produced at higher current densities. These results show that the electrochemical activity of SD-1 was significantly different than other Geobacter strains and mixed cultures in terms of its salt tolerance.

  18. G eobacter sp. SD-1 with enhanced electrochemical activity in high-salt concentration solutions

    KAUST Repository

    Sun, Dan

    2014-07-16

    © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd. Summary: An isolate, designated strain SD-1, was obtained from a biofilm dominated by Geobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD-1 was compared with type strains, G.sulfurreducensPCA and Geobacter metallireducensGS-15, and a mixed culture in microbial electrolysis cells. SD-1 produced a maximum current density of 290±29Am-3 in a high-concentration phosphate buffer solution (PBS-H, 200mM). This current density was significantly higher than that produced by the mixed culture (189±44Am-3) or the type strains (<70Am-3). In a highly saline water (SW; 50mM PBS and 650mM NaCl), current by SD-1 (158±4Am-3) was reduced by 28% compared with 50mM PBS (220±4Am-3), but it was still higher than that of the mixed culture (147±19Am-3), and strains PCA and GS-15 did not produce any current. Electrochemical tests showed that the improved performance of SD-1 was due to its lower charge transfer resistance and more negative potentials produced at higher current densities. These results show that the electrochemical activity of SD-1 was significantly different than other Geobacter strains and mixed cultures in terms of its salt tolerance.

  19. Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

    Science.gov (United States)

    Amitai, Yona; Winston, Gary; Sack, Joseph; Wasser, Janice; Lewis, Matthew; Blount, Benjamin C; Valentin-Blasini, Liza; Fisher, Nirah; Israeli, Avi; Leventhal, Alex

    2007-09-01

    To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

  20. Electrical resistivity of liquid iron with high concentration of light element impurities

    Science.gov (United States)

    Wagle, F.; Steinle-Neumann, G.

    2017-12-01

    The Earth's outer core mainly consists of liquid iron, enriched with several weight percent of lighter elements, such as silicon, oxygen, sulfur or carbon. Electrical resistivities of alloys of this type determine the stability of the geodynamo. Both computational and experimental results show that resistivites of Fe-based alloys deviate significantly from values of pure Fe. Using optical conductivity values computed with the Kubo-Greenwood formalism for DFT-based molecular dynamics results, we analyze the high-P and T behavior of resitivities for Fe-alloys containing various concentrations of sulfur, oxygen and silicon. As the electron mean free path length in amorphous and liquid material becomes comparable to interatomic distances at high P and T, electron scattering is expected to be dominated by the short-range order, rather than T-dependent vibrational contributions, and we describe such correlations in our results. In analogy to macroscopic porous media, we further show that resistivity of a liquid metal-nonmetal alloy is determined to first order by the resistivity of the metallic matrix and the volume fraction of non-metallic impurities.

  1. Examination of hepatic dynamic CT images following infusion of high-concentration contrast media

    International Nuclear Information System (INIS)

    Takeyama, Nobuyuki; Hayashi, Takaki; Kinebuchi, Yuko; Kitahara, Tadashi; Ohbuchi, Masao; Shinjyo, Hidenori; Ohgiya, Yoshimitsu

    2008-01-01

    There are scarce examinations on the integrated effects of given iodine weight (mgI) and its rate (mgI/sec) on the quality and diagnostic accuracy in the hepatic contrast CT imaging while the former is known to affect the image of parenchyma and the latter, of arterial systems. The purpose of this study is to analyze and evaluate the effects qualitatively and quantitatively in hepatic dynamic CT images of patients with moderate body weight in whom different concentrations of I are given at the same flux rate and total weight. Patients having chronic hepatitis suspicious of carcinoma, or cirrhosis were 52-84 years old (M 50/F 55, b. wt. 50-65 kg) and were randomly divided in A and B group. A group received infusion of 25 sec in the right elbow vein of iopamidol, 300 mgI/100 mL, and B group, 370 mgI/80 mL: the I flux of ca. 1.2 gI/sec and total I of ca. 30 gI. Before and at 25 (early arterial phase), 40 (late art. phase), 70 (portal vein) and 180 (equilibrium) sec after infusion, CT images were obtained with the machine Light Speed select (GE Healthcare), Housfield Units before and after enhancing were used for quantitative evaluation, three experts qualitatively read images, and PACS system in Synapse 3.1.0 (Fuji Film Med.) was used for observation of tumor nodules if present. Neither qualitative nor quantitative differences were found in these CT images of the 4 phases and use of high-concentration contrast media was confirmed to be possible for lowered infusion rate. Authors also pointed out the importance of care for radiation exposure in this CT technique. (R.T.)

  2. Calorie Restricted High Protein Diets Downregulate Lipogenesis and Lower Intrahepatic Triglyceride Concentrations in Male Rats

    Directory of Open Access Journals (Sweden)

    Lee M. Margolis

    2016-09-01

    Full Text Available The purpose of this investigation was to assess the influence of calorie restriction (CR alone, higher-protein/lower-carbohydrate intake alone, and combined CR higher-protein/lower-carbohydrate intake on glucose homeostasis, hepatic de novo lipogenesis (DNL, and intrahepatic triglycerides. Twelve-week old male Sprague Dawley rats consumed ad libitum (AL or CR (40% restriction, adequate (10%, or high (32% protein (PRO milk-based diets for 16 weeks. Metabolic profiles were assessed in serum, and intrahepatic triglyceride concentrations and molecular markers of de novo lipogenesis were determined in liver. Independent of calorie intake, 32% PRO tended to result in lower homeostatic model assessment of insulin resistance (HOMA-IR values compared to 10% PRO, while insulin and homeostatic model assessment of β-cell function (HOMA-β values were lower in CR than AL, regardless of protein intake. Intrahepatic triglyceride concentrations were 27.4 ± 4.5 and 11.7 ± 4.5 µmol·g−1 lower (p < 0.05 in CR and 32% PRO compared to AL and 10% PRO, respectively. Gene expression of fatty acid synthase (FASN, stearoyl-CoA destaurase-1 (SCD1 and pyruvate dehydrogenase kinase, isozyme 4 (PDK4 were 45% ± 1%, 23% ± 1%, and 57% ± 1% lower (p < 0.05, respectively, in CR than AL, regardless of protein intake. Total protein of FASN and SCD were 50% ± 1% and 26% ± 1% lower (p < 0.05 in 32% PRO compared to 10% PRO, independent of calorie intake. Results from this investigation provide evidence that the metabolic health benefits associated with CR—specifically reduction in intrahepatic triglyceride content—may be enhanced by consuming a higher-protein/lower-carbohydrate diet.

  3. Mechanism of de-activation and clustering of B in Si at extremely high concentration

    International Nuclear Information System (INIS)

    Romano, L.; Piro, A.M.; Privitera, V.; Rimini, E.; Fortunato, G.; Svensson, B.G.; Foad, M.; Grimaldi, M.G.

    2006-01-01

    It is known that B deactivation and clustering occur in the presence of an excess of Si self-interstitials (Is). First principle calculations predicted the path of clusters growth, but the precursor complexes are too small to be visible even by the highest resolution microscopy. Channeling with nuclear reaction analyses allowed to detect the location of small B-Is complexes into the lattice formed as a consequence of the B interaction with the Is. In this work we extend this method to determine the complexes formed during the initial stage of B precipitation in Si doped at extremely high concentration (4 at%) and subjected to thermal treatment. The samples were prepared by excimer laser annealing (ELA) of Si implanted with 1 keV B. The thickness of the molten layer was 100 nm and the B profile was boxlike with a maximum hole concentration of ∼2 x 10 21 cm -3 . The electrical deactivation and carrier mobility of this metastable system has been studied as a function of subsequent annealing in the temperature range between 200 and 850 deg. C. Channeling analyses have been performed to investigate the B lattice location at the initial stage of precipitation. The difference, with respect to previous investigations, is the very small distance (<1 nm) between adjacent B atoms substitutional located in the lattice and the absence of Is that can be released during annealing, since the end of range defects were completely dissolved by ELA. In this way, information on the B complex evolution in a free-of-defects sample have been obtained

  4. Mangiferin binding to serum albumin is non-saturable and induces conformational changes at high concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, P.G.; Barbosa, A.F. [Biochemistry Laboratory, Institute of Exact Sciences, Federal University of Alfenas, Unifal-MG, R. Gabriel Monteiro da Silva, 700, 37130-000 Alfenas, MG (Brazil); Saraiva, L.A. [Phytochemistry and Medicinal Chemistry Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Camps, I. [Physics Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Silveira, N.J.F. da [Bioinformatics Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Veloso, M.P. [Phytochemistry and Medicinal Chemistry Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Santos, M.H., E-mail: poliany.santos@gmail.com [Phytochemistry and Medicinal Chemistry Laboratory, Institute of Exact Sciences, Unifal-MG (Brazil); Schneedorf, J.M., E-mail: zemasfs@gmail.com [Biochemistry Laboratory, Institute of Exact Sciences, Federal University of Alfenas, Unifal-MG, R. Gabriel Monteiro da Silva, 700, 37130-000 Alfenas, MG (Brazil)

    2012-11-15

    The binding interaction between mangiferin (MGF), which a natural xanthone isolated from mangoes, and bovine serum albumin (BSA) was studied with absorbance and fluorescence spectroscopy, cyclic voltammetry and molecular modeling. The data were analyzed to assess the binding mechanism, effect of pH and ionic strength, conformational changes in the protein and electrical charge transfer involved. The MGF-BSA complex exhibited positive cooperativity with a 1:1 stoichiometry (K{sub d}=0.38 mmol L{sup -1}) for the first binding site and a non-saturable binding at high ligand concentrations. Furthermore, the data also suggest an increase in drug bioavailability in the acidic region and relatively low ionic strength values, which are close to physiological levels. The data suggest a specific electrostatic interaction together with hydrophobic effects and H-bonding displayed in MGF binding to the BSA IIA subdomain. Synchronous fluorescence spectra indicate that there are conformational changes in the polypeptide backbone upon ligand binding. Cyclic voltammetry indicates that there is an irreversible charge transfer between MGF and BSA that is modulated by diffusion on the electrode surface, where two electrons are transferred. These results can help the knowledge of the pharmacokinetic activities of natural or chemical xanthone-based drugs. - Highlights: Black-Right-Pointing-Pointer The MGF-BSA complex exhibited positive cooperativity beyond 1:1 stoichiometry. Black-Right-Pointing-Pointer The interaction of MGF with BSA is non-saturable at higher ligand concentration. Black-Right-Pointing-Pointer The binding was accomplished by H-bonding, hydrophobic and electrostatic forces. Black-Right-Pointing-Pointer The apparent binding constant for MGF-BSA was 0.38 mmol L{sup -1}. Black-Right-Pointing-Pointer MGF binds electrostatically to BSA, different from a hydrophobic interaction to HSA.

  5. Genomic and transcriptomic insights into how bacteria withstand high concentrations of benzalkonium chloride biocides.

    Science.gov (United States)

    Kim, Minjae; Hatt, Janet K; Weigand, Michael R; Krishnan, Raj; Pavlostathis, Spyros G; Konstantinidis, Konstantinos T

    2018-04-13

    Benzalkonium chlorides (BAC) are commonly used biocides in broad-spectrum disinfectant solutions. How microorganisms cope with BAC exposure remains poorly understood, despite its importance for disinfection and disinfectant-induced antibiotic resistance. To provide insights into these issues, we exposed two isolates of an opportunistic pathogen, Pseudomonas aeruginosa , to increasing concentrations of BAC. One isolate was pre-adapted to BAC as it originated from a bioreactor fed with sub-inhibitory concentrations of BAC for 3 years, while the other originated from a bioreactor that received no BAC. Replicated populations of both isolates were able to survive high concentrations of BAC, up to 1200 and 1600mg/L for the non- and pre-adapted ones, respectively, exceeding typical application doses. RNA-seq analysis revealed up-regulation of efflux pump genes and decreased expression of porins related to BAC transport as well as reduced growth rate. Increased expression of spermidine (a polycation) synthase genes and mutations in the pmrB (polymyxin resistance) gene, which cause a reduction in membrane negative charge, suggested that a major adaptation to exposure to the cationic surfactant BAC was to actively stabilize cell surface charge. Collectively, these results revealed that P. aeruginosa adapts to BAC exposure by a combination of mechanisms, and provided genetic markers to monitor BAC-resistant organisms that may have applications in the practice of disinfection. Importance Benzalkonium chlorides (BAC) are widely used as biocides in disinfectant solutions, food processing lines, domestic households, and healthcare facilities. Due to their wide use and mode of action, there has been rising concern that BAC may promote antibiotic resistance. Consistently, at least 40 outbreaks have been attributed to infection by disinfectant- and antibiotic-resistant pathogens such as Pseudomonas aeruginosa However, the underlying molecular mechanisms that bacteria deal with BAC

  6. High salt inclusion reduces concentrate intake without major effects on renal function in young bulls

    Directory of Open Access Journals (Sweden)

    Mireia Blanco

    2014-08-01

    Full Text Available Beef producers prefer to feed concentrates on an ad libitum basis to increase the flexibility of their work. Including salt, which is a self-limiting supplement, could control or reduce concentrate intake without increasing the workforce. The aim of the study was to evaluate the effect of including 10%NaCl in the concentrate on intake, growth, blood ions (sodium, potassium and chlorine, renal function (through creatinine and urea concentrations in blood, and daytime behaviour of bulls over 6 weeks. Bulls consuming the control concentrate (Control bulls had greater weight gain (P<0.05 and concentrate intake (P<0.001 than those consuming the concentrate with 10%NaCl (10%NaCl bulls. Lower plasma sodium concentration was found in Control bulls after 6 weeks (P<0.05, while potassium concentration was lower after 4 (P<0.05 and 6 weeks (P<0.01. Blood urea did not differ between the groups, and creatinine only differed at week 4 (P<0.01. Control bulls spent less time eating hay (P<0.001 and more time idling (P<0.01 during daylight hours. In conclusion, the inclusion of 10%NaCl in the concentrate for short periods could be used to reduce concentrate intake without major effects on renal function; however, a concomitant decrease in weight gain should be expected.

  7. In vitro characterization of high purity factor IX concentrates for the treatment of hemophilia B.

    Science.gov (United States)

    Limentani, S A; Gowell, K P; Deitcher, S R

    1995-04-01

    This study employed sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoblotting to assess the purity of seven high purity factor IX concentrates: Aimafix (Aima), AlphaNine-SD (Alpha Therapeutic), Factor IX VHP (Biotransfusion), Immunine (Immuno), Mononine (Armour Pharmaceutical), Nanotiv (Kabi Pharmacia), and 9MC (Blood Products Laboratory). The mean specific activity of these products ranged from 68 U factor IX/mg (Aimafix) to 246 U factor IX/mg (Mononine). SDS-PAGE analysis showed that the highest purity product, Mononine, had a single contaminating band under non-reducing conditions. Two additional bands were detected when this product was analyzed under reducing conditions. All other products had multiple contaminating bands that were more apparent under reducing than non-reducing conditions. The immunoblot for factor IX showed a dominant factor IX band for all products. In addition, visible light chain of factor IX was detected for AlphaNine-SD, Factor IX VHP, Immunine, Mononine, Nanotiv, and 9MC, suggesting that the factor IX in these products had undergone partial activation to factor IXa. Another contaminating band was visible at 49,500 for all of the products except 9MC. In addition to this band, high molecular weight contaminants were apparent for some products, most notably AlphaNine-SD. The identity of these bands is unknown. Immunoblotting failed to demonstrate factor VII as a contaminant of any of the high purity products, although factor VIIa could be detected in some lots of Immunine, Nanotiv, and 9MC by a clot-based assay. Factor X contaminated Aimafix, AlphaNine-SD, Factor IX VHP, Immunine, Nanotiv, and 9MC, but activation products of factor X were not detected.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Incorporation of the stress concentration slots into the flexures for a high-performance microaccelerometer

    International Nuclear Information System (INIS)

    Zhao Yulong; Sun Lu; Liu Yan; Wang Weizhong; Tian Bian

    2012-01-01

    Presented in this paper is a development of a high-performance piezoresistive microaccelerometer based on the slot etching in the quad flexures for the vibration detection of high speed spindle. The proposed structure consists of a proof mass supported by four thin flexures with slots etched in the middle. Boron diffused piezoresistors located near the stress concentration regions are used for sensing the localized stress resulting from the incorporation of the slots into the flexures. Theoretical analysis and finite element analysis show satisfactory results of an improved sensitivity and favorable natural frequency higher than 10 kHz, conforming to the initial design requirements. The microfabrication techniques are described to prototype the two accelerometer chips, one with slots and the other one without slots. The tested microaccelerometers with 3 V DC power supply show an average sensitivity of 0.424 mV/g normal to the proof mass plane, increased by 60.6% than the ones without slots. An average transverse sensitivity is found to be 9.2 μV/g along X axis and 14.2 μV/g along Y axis, either of which is less than 3.5% of prime-axis sensitivity. Concerning the resonant frequency, dynamic experiment shows about 12.46 kHz and is available for the proposed design with a tiny loss of 3.5% compared with the quad-beam design. When taking the product of sensitivity and natural frequency as judgment criteria, an inspiring increase by 28.6% of the figure of merit is accomplished for the proposed accelerometer. Overall, the findings of this study confirm the feasibility of incorporating slots into the conventional configurations to improve the sensor sensitivity while maintaining a comparatively high natural frequency.

  9. Treatment of marine sewage pumpout and RV park pumpout wastewater containing high strength concentrations of formaldehyde

    International Nuclear Information System (INIS)

    Salonich, J.

    2002-01-01

    'Full text:' A consortium of companies has developed an integrated 'on-site' wastewater treatment technology that is capable of handling and degrading RV Park and Marine Sewage Pumpout Wastes which contain formaldehyde [35 - 80 mg/L]. Boat and RV owners add formaldehyde to their toilets to eliminate odors. When these materials are pumped out they are high in solids content and have high concentrations of HCHO, which makes them difficult to degrade at POTWs. At the heart of this process is 1. An aeration tank with a Venturi Aerator totally external to the tank and 2. The addition of a blend of cultured bacteria that have selected for their ability to degrade formaldehyde. For a complete 'on-site' treatment system Bioclere Trickling Filters can follow this aeration/bacterial treatment system. This is an ideal system configuration for remote locations (RV Parks) or for fresh water lake Marinas looking to reduce their disposal costs and for groundwater discharge with no adverse effect on water quality. Until the development of the formaldehyde degrading bacteria for an industrial wastewater process there were no cultures commercially available specifically for degrading formaldehyde. The most commonly used bacteria were pseudomonas strains for carbohydrate or hydrocarbon wastewater extracted from activated sludge plants. And since formaldehyde is infinitely soluble in a liquid it is difficult to degrade or mineralize. The process in an activated sludge WWTP plant took over 72 hours. With the newly selected consortia of cultures, HCHO can be degraded in 12-14 hours on a batch basis. This is accomplished in a uniquely configured aeration tank where the 'environment' of the tank is constantly conditioned by a Venturi Aerator which strips carbon dioxide generated by the aerobes to maintain a neutral pH, and provide high levels of DO (>5.0 mg/L) to keep the process aerobic. (author)

  10. Tri-Lateral Noor al Salaam High Concentration Solar Central Receiver Program

    Energy Technology Data Exchange (ETDEWEB)

    Blackmon, James B

    2008-03-31

    This report documents the efforts conducted primarily under the Noor al Salaam (“Light of Peace”) program under DOE GRANT NUMBER DE-FC36-02GO12030, together with relevant technical results from a closely related technology development effort, the U.S./Israel Science and Technology Foundation (USISTF) High Concentration Solar Central Receiver program. These efforts involved preliminary design, development, and test of selected prototype power production subsystems and documentation of an initial version of the system definition for a high concentration solar hybrid/gas electrical power plant to be built in Zaafarana, Egypt as a first step in planned commercialization. A major part of the planned work was halted in 2007 with an amendment in October 2007 requiring that we complete the technical effort by December 31, 2007 and provide a final report to DOE within the following 90 days. This document summarizes the work conducted. The USISTF program was a 50/50 cost-shared program supported by the Department of Commerce through the U.S./Israel Science and Technology Commission (USISTC). The USISTC was cooperatively developed by President Clinton and the late Prime Minister Rabin of Israel "to encourage technological collaboration" and "support peace in the Middle East through economic development". The program was conducted as a follow-on effort to Israel's Magnet/CONSOLAR Program, which was an advanced development effort to design, fabricate, and test a solar central receiver and secondary optics for a "beam down" central receiver concept. The status of these hardware development programs is reviewed, since they form the basis for the Noor al Salaam program. Descriptions are provided of the integrated system and the major subsystems, including the heliostat, the high temperature air receiver, the power conversion unit, tower and tower reflector, compound parabolic concentrator, and the master control system. One objective of the USISTF program was to conduct

  11. Are There High Meteorite Concentrations in the Atacama Desert/Chile?

    Science.gov (United States)

    Scherer, P.; Delisle, G.

    1992-07-01

    We have visited numerous regions of the Atacama desert between Copiapo (27 degrees, 15'S) and Calama (22 degrees, 25'S) to assess their potential as a high-yield meteorite concentration surface, easily exploitable by search efforts within a reasonable time frame. According to our observations, this desert is characterized by the following features: a) A high percentage of the desert consists of sloping surfaces on which soil movement occurs, presumably by very infrequent, though heavy rain. b) Vast areas of the desert are covered by a dm-thick sand layer of dark colour. Since the sand is too coarse-grained to be transported by wind it presumably resulted from in-situ weathering of rock debris derived from nearby mountains. We suspect that impacting smaller objects can easily penetrate the sand layer. c) The sand layer is typically dotted by rocks, fist-size or smaller, that are covered by a thick layer of desert paint (reddish-brown to black colour). Most country rocks are of volcanic origin (rhyolite, andesite, basalt) and are typically of grey to black colour. A noticeable colour contrast in particular to potential stony meteorites is almost nonexistent. d) Soil salts with a potential to speed up weathering processes are ubiquitous near the surface. e) The Pampa de Mejillones, 45 km north of Antofagasta, is one of the few light-coloured areas in the Atacama desert. The surface, being of Mio-Pliocene age, consists of an almost continuous layer of light-brown fossil shells (bivalves and gastropodes). Fluvially transported dark rocks from adjacent outcrops rest on top. The latter material is covered again by desert paint. Few meteorite discoveries have been reported from this area (Pampa (a),(b),(c)). f) Numerous old tire tracks, in particular around mines in operation, crisscross most areas of the Atacama. Undetected objects such as large masses of iron bodies are not likely to have remained undiscovered in great numbers any more. We conclude that the potential of

  12. Fibrinogen and thrombin concentrations are critical for fibrin glue adherence in rat high-risk colon anastomoses

    Directory of Open Access Journals (Sweden)

    Eliseo Portilla-de Buen

    2014-04-01

    Full Text Available OBJECTIVE: Fibrin glues have not been consistently successful in preventing the dehiscence of high-risk colonic anastomoses. Fibrinogen and thrombin concentrations in glues determine their ability to function as sealants, healers, and/or adhesives. The objective of the current study was to compare the effects of different concentrations of fibrinogen and thrombin on bursting pressure, leaks, dehiscence, and morphology of high-risk ischemic colonic anastomoses using fibrin glue in rats. METHODS: Colonic anastomoses in adult female Sprague-Dawley rats (weight, 250-350 g treated with fibrin glue containing different concentrations of fibrinogen and thrombin were evaluated at post-operative day 5. The interventions were low-risk (normal or high-risk (ischemic end-to-end colonic anastomoses using polypropylene sutures and topical application of fibrinogen at high (120 mg/mL or low (40 mg/mL concentrations and thrombin at high (1000 IU/mL or low (500 IU/mL concentrations. RESULTS: Ischemia alone, anastomosis alone, or both together reduced the bursting pressure. Glues containing a low fibrinogen concentration improved this parameter in all cases. High thrombin in combination with low fibrinogen also improved adherence exclusively in low-risk anastomoses. No differences were detected with respect to macroscopic parameters, histopathology, or hydroxyproline content at 5 days post-anastomosis. CONCLUSIONS: Fibrin glue with a low fibrinogen content normalizes the bursting pressure of high-risk ischemic left-colon anastomoses in rats at day 5 after surgery.

  13. Evaluation of the acute adverse reaction of contrast medium with high and moderate iodine concentration in patients undergoing computed tomography

    International Nuclear Information System (INIS)

    Nagamoto, Masashi; Gomi, Tatsuya; Terada, Hitoshi; Terada, Shigehiko; Kohda, Eiichi

    2006-01-01

    The aim of this prospective study was to evaluate and compare acute adverse reactions between contrast medium containing moderate and high concentrations of iodine in patients undergoing computed tomography (CT). A total of 945 patients undergoing enhanced CT were randomly assigned to receive one of two doses of contrast medium. We then prospectively investigated the incidence of adverse reactions. Iopamidol was used as the contrast medium, with a high concentration of 370 mgI/ml and a moderate concentration of 300 mgI/ml. The frequency of adverse reactions, such as pain at the injection site and heat sensation, were determined. Acute adverse reactions were observed in 2.4% (11/458) of the moderate-concentration group compared to 3.11% (15/482) of the high-concentration group; there was no significant difference in incidence between the two groups. Most adverse reactions were mild, and there was no significant difference in severity. One patient in the high-concentration group was seen to have a moderate adverse reaction. No correlation existed between the incidence of adverse reactions and patient characteristics such as sex, age, weight, flow amount, and flow rate. The incidence of pain was not significantly different between the two groups. In contrast, the incidence of heat sensation was significantly higher in the high-concentration group. The incidence and severity of acute adverse reactions were not significantly different between the two groups, and there were no severe adverse reactions in either group. (author)

  14. The flow field structure of highly stabilized partially premixed flames in a concentric flow conical nozzle burner with coflow

    KAUST Repository

    Elbaz, Ayman M.; Zayed, M.F.; Samy, M.; Roberts, William L.; Mansour, Mohy S.

    2015-01-01

    The stability limits, the stabilization mechanism, and the flow field structure of highly stabilized partially premixed methane flames in a concentric flow conical nozzle burner with air co-flow have been investigated and presented in this work

  15. A technology for production of a ''Cureless'' paste containing a high concentration of tetrabasic lead sulfate and a low concentration of free lead

    Energy Technology Data Exchange (ETDEWEB)

    Boden, David P.; Loosemore, Daniel [Hammond Lead Products, Division of Hammond Group Inc., 6544 Osborn Avenue, Hammond, IN 46320 (United States)

    2007-05-25

    The conventional paste used to produce plates for lead-acid batteries comprises a mixture of leady oxide, water and sulfuric acid. Fibre and other additives, such as expander in negative plates, are added to improve paste properties and battery performance. Following pasting of the plates, they have to be cured to provide the correct chemical composition and crystal morphology, and to oxidize any residual free lead metal to lead monoxide. The desired result of the curing process is a positive plate with a high concentration of uniformly sized tetrabasic lead sulfate (4BS) crystals and with both positive and negative plates having a low concentration of free lead. Curing is a time-consuming and expensive process, which requires large numbers of chambers capable of being heated to 85 C and containing an atmosphere with a relative humidity greater than 95%. This process adds significant cost to the battery. (author)

  16. Development and impact of hooks of high droplet concentration on remote southeast Pacific stratocumulus

    Directory of Open Access Journals (Sweden)

    R. C. George

    2013-07-01

    Full Text Available Over the southeastern Pacific (SEP, droplet concentration (Nd in the typically unpolluted marine stratocumulus west of 80° W (> 1000 km offshore is periodically strongly enhanced in zonally elongated "hook"-shaped features that increase albedo. Here, we examine three hook events using the chemistry version of the Weather Research and Forecasting model (WRF-Chem with 14 km horizontal resolution, satellite data, and aircraft data from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx. A particularly strong hook yields insights into the development, decay, and radiative impact of these features. Hook development occurs with Nd increasing to polluted levels over the remote ocean primarily due to entrainment of cloud condensation nuclei (CCN from the lower free troposphere (FT. The feature advects northwestward until the FT CCN source is depleted, after which Nd decreases over a few days due to precipitation and dilution. The model suggests that the FT CCN source supplying the hook consists of high concentrations of small accumulation-mode aerosols that contribute a relatively small amount of aerosol mass to the MBL, in agreement with near-coast VOCALS measurements of polluted layers in the FT. The aerosol particles in this hook originate mainly from a pulse of offshore flow that transports Santiago-region (33–35° S emissions to the remote marine FT. To provide pollution CCN that can sustain hooks, the FT transport of pollution plumes to the remote ocean requires strong, deep offshore flow. Such flow is favored by a trough approaching the South American coast and a southeastward shift of the climatological subtropical high-pressure system. The model simulations show precipitation suppression in the hook and a corresponding increase in liquid water path (LWP compared with a simulation without anthropogenic sources. LWP also increases as the hook evolves over time due to increasing stability and decreasing subsidence. WRF

  17. Relationships Between Land Use and Stream Nutrient Concentrations in a Highly Urbanized Tropical Region of Brazil: Thresholds and Riparian Zones.

    Science.gov (United States)

    Tromboni, F; Dodds, W K

    2017-07-01

    Nutrient enrichment in streams due to land use is increasing globally, reducing water quality and causing eutrophication of downstream fresh and coastal waters. In temperate developed countries, the intensive use of fertilizers in agriculture is a main driver of increasing nutrient concentrations, but high levels and fast rates of urbanization can be a predominant issue in some areas of the developing world. We investigated land use in the highly urbanized tropical State of Rio de Janeiro, Brazil. We collected total nitrogen, total phosphorus, and inorganic nutrient data from 35 independent watersheds distributed across the State and characterized land use at a riparian and entire watershed scales upstream from each sample station, using ArcGIS. We used regression models to explain land use influences on nutrient concentrations and to assess riparian protection relationships to water quality. We found that urban land use was the primary driver of nutrient concentration increases, independent of the scale of analyses and that urban land use was more concentrated in the riparian buffer of streams than in the entire watersheds. We also found significant thresholds that indicated strong increases in nutrient concentrations with modest increases in urbanization reaching maximum nutrient concentrations between 10 and 46% urban cover. These thresholds influenced calculation of reference nutrient concentrations, and ignoring them led to higher estimates of these concentrations. Lack of sewage treatment in concert with urban development in riparian zones apparently leads to the observation that modest increases in urban land use can cause large increases in nutrient concentrations.

  18. The association between etanercept serum concentration and psoriasis severity is highly age-dependent.

    Science.gov (United States)

    Detrez, Iris; Van Steen, Kristel; Segaert, Siegfried; Gils, Ann

    2017-06-01

    The association between etanercept serum concentration and psoriasis disease severity is poorly investigated, and currently etanercept serum concentration monitoring that is aiming to optimize the psoriasis treatment lacks evidence. In this prospective study, we investigated the relation between etanercept exposure and disease severity via measuring etanercept concentrations at five consecutive time points in 56 psoriasis patients. Disease severity assessments included the Psoriasis Area and Severity Index (PASI), body surface area (BSA) and Physician Global Assessment (PGA), and etanercept and anti-etanercept antibody concentrations were determined every 3 months for a period of 1 year. The present study demonstrated that the association between etanercept concentration and psoriasis severity is age-dependent: when patients were stratified into three groups, patients in the youngest age group (-50 years) showed a lower PASI at a higher etanercept concentration (β = -0.26), whereas patients in the oldest age group (+59 years) showed the opposite trend (β =0.22). Similar age effects were observed in the relation of etanercept concentration with BSA ( P =0.02) and PGA ( P =0.02). The influence of age and length of time in therapy on the etanercept concentration-disease severity relation was unaffected by body mass index (BMI) or any other possible confounder. Incidence of anti-etanercept antibodies was low (2%). The age-dependent relation between etanercept serum concentrations is both unexpected and intriguing and needs further investigation. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  19. Gold Leaching Characteristics and Intensification of a High S and As-Bearing Gold Concentrate

    Science.gov (United States)

    Yang, Yong-bin; Liu, Xiao-liang; Jiang, Tao; Li, Qian; Xu, Bin; Zhang, Yan

    Some high sulfur and arsenic-bearing gold concentrate has a gold leaching rate less than 80% by oxidation roasting-pickling-cyanidation process. The characteristics and intensification of gold leaching were studied systemically. By combining chemical composition and phase analysis, the low gold leaching rate was found to lie in the capsulation of gold by iron-containing phases including iron oxides, arsenopyrite and pyrite. 96.66% of gold in the industrial leaching residue was capsulated and 95.88% of the capsulated turned out to be in the iron-containing phases. The results of laboratory pickling-cyanidation experiments on the calcine and industrial leaching residue presented further demonstration for the fact that gold capsulated in the iron-containing phases was hard to be leached. However, the gold cyanide leaching rate of calcine could be raised over 95% by a reduction roasting-pickling pretreatment which played such a significant role in exposing the capsulated gold that gold leaching was intensified remarkably.

  20. Enhanced growth of the red alga Porphyra-Yezoensis Ueda in high CO sub 2 concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Gao, K.; Aruga, Y.; Asada, K.; Ishihara, T.; Akano, T.; Kiyohara, M. (Kansai Environmental Engineering Centre, Osaka (Japan))

    1991-12-01

    Leafy thalli of the red alga Porphyra yezoensis Ueda, initiated from conchospores released from free-living conchocelis, were cultured using aeration with high CO{sub 2}. It was found that the higher the CO{sub 2} concentration, the faster the growth of the thalli. Aeration with elevated CO{sub 2} lowered pH in dark, but raised pH remarkably in light with the thalli, because the photosynthetic conversion of HCO{sub 3} {sup -} to OH{sup -} and CO{sub 2} proceeded much faster than the dissociation of hydrated CO{sub 2} releasing H{sup +}. Photosynthesis of the alga was found to be enhanced in the seawater of elevated dissolved inorganic carbon DIC, CO{sub 2} + HCO{sub 3}{sup -} + CO{sub 3}{sup -}. It is concluded that the increased pH in the light resulted in the increase of DIC in the culture media, thus enhancing photosynthesis and growth. The relevance of the results to removal of atmospheric CO{sub 2} by marine algae is discussed.

  1. Effect of growing plants on denitrification at high soil nitrate concentrations

    International Nuclear Information System (INIS)

    Haider, K.; Mosier, A.; Heinemeyer, O.

    1987-01-01

    The availability of plant rhizosphere C deposits and its influence on microbial denitrification is not clearly defined. Conflicting reports as to the influence of plants and root exudation on denitrification continue to appear in the literature. The results of the authors earlier phytotron study indicated that denitrification was not stimulated in soils planted with corn or wheat compared to unplanted soils. Lower nitrate concentrations in the planted soils, however, may have led to misinterpretation of this data. A second study was conducted, to evaluate the effect of actively growing plants on denitrification where the NO 3 7 content of planted soils was maintained similar to unplanted soils. Simultaneously the C fixed by corn (Zea mays) and the fate of fertilizer N applied to the soil during the growing season were quantified. The corn was grown in a phytotron under a continuous supply of 14 CO 2 in 15 N fertilized soils to which 15 N-NO 3 - was added periodically during the growing season. The results of these studies showed that denitrification was not stimulated in soils planted with corn during active plant growth phase even when soil NO 3 - was relatively high. Denitrification was, however, greater in corn planted than unplanted soil when the recoverable root biomass began to decrease. Less N was immobilized and net 15 N immobilization was lower in planted soils than in unplanted soils. As denitrification was lower in planted soils during the time of active plant growth, the study suggests that root exudates did not stimulate either process

  2. Efficient fermentation of xylose to ethanol at high formic acid concentrations by metabolically engineered Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Hasunuma, Tomohisa; Yoshimura, Kazuya; Matsuda, Fumio [Kobe Univ., Hyogo (Japan). Organization of Advanced Science and Technology; Sung, Kyung-mo; Sanda, Tomoya; Kondo, Akihiko [Kobe Univ., Hyogo (Japan). Dept. of Chemical Science and Engineering

    2011-05-15

    Recombinant yeast strains highly tolerant to formic acid during xylose fermentation were constructed. Microarray analysis of xylose-fermenting Saccharomyces cerevisiae strain overexpressing endogenous xylulokinase in addition to xylose reductase and xylitol dehydrogenase from Pichia stipitis revealed that upregulation of formate dehydrogenase genes (FDH1 and FDH2) was one of the most prominent transcriptional events against excess formic acid. The quantification of formic acid in medium indicated that the innate activity of FDH was too weak to detoxify formic acid. To reinforce the capability for formic acid breakdown, the FDH1 gene was additionally overexpressed in the xylose-metabolizing recombinant yeast. This modification allowed the yeast to rapidly decompose excess formic acid. The yield and final ethanol concentration in the presence of 20 mM formic acid is as essentially same as that of control. The fermentation profile also indicated that the production of xylitol and glycerol, major by-products in xylose fermentation, was not affected by the upregulation of FDH activity. (orig.)

  3. Characterization of gypsum crystals exposed to a high CO2 concentration fog using x-ray

    International Nuclear Information System (INIS)

    Carreño-Márquez, I. J. A.; Castillo-Sandoval, I.; Esparza-Ponce, H. E.; Fuentes-Cobas, L.; Montero-Cabrera, M. E.

    2015-01-01

    In Chihuahua State, a little town called Naica has the largest gypsum single crystals in the world. The growth of these structures has been described as a long and stable process developed over thousands of years. Due to the change in the environmental conditions, these crystals could suffer alterations on their surface. In this project we study the cause of possible deterioration of the giant crystals and intend to suggest measures for their preservation. For this sake, our first experiment consists on several gypsum crystals that have been subjected in a climate chamber to a fog at high CO 2 concentration and 51 °C for a period of time of six months, extracting two crystals every 15 days. Then the crystals have been characterized through Grazing Incidence X-Ray Diffraction using a diffractometer PanAlytical X’PertPro with two different detectors; Xe-filled proportional detector and a Pixel 3D detector. The results were compared to determine which technique is the most suitable to study the degradation of gypsum single crystals. In the two cases, we have identified only the gypsum phase, but with different crystal plane orientations

  4. Struvite Crystallization of Anaerobic Digestive Fluid of Swine Manure Containing Highly Concentrated Nitrogen

    Directory of Open Access Journals (Sweden)

    Eun Young Lee

    2015-07-01

    Full Text Available In this study, the optimal operation factors for struvite crystallization for removing and recovering nitrogen and phosphorus from anaerobic digestive fluid of swine manure containing highly concentrated nitrogen was determined. Every experiment for the struvite crystallization reaction was conducted by placing 1,000 mL of digestion fluid in a 2,000 mL Erlenmeyer flask at various temperatures, pH, and mixing speed. Except for special circumstances, the digestion fluid was centrifuged (10,000 rpm, 10 min and then the supernatant was used for the experiment at room temperature and 100 rpm. The optimal mole ratio of PO43−:Mg2+ was 1:1.5, and the pH effect ranging from 9 to 11 was similar, when mixed for 1 hour. Under this condition, the removal efficiency of NH4+-N and PO43−-P was 40% and 88.6%, respectively. X-shaped crystal was observed by light and scanning electron microscopy. In addition, struvite crystal structure was confirmed through X-ray diffraction analysis.

  5. High concentrations of radon. Specifically affected buildings; Hohe Radonkonzentrationen. Besonders betroffene Gebaeudetypen

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Winfried [Bundesamt fuer Strahlenschutz, Berlin (Germany)

    2015-07-01

    The paper presents a concept for the prognosis of exceeding probabilities of thresholds of radon in dwellings in different building types. A transfer model for the interface subsoil - building was used as a basis. The partial datasets obtained by stratification of five relevant building characteristics can be de-scribed by a 3-parametric-lognormal distribution good in most times. The available data permit statistical predictions to 60 combinations of building characteristics for the region ''east'' and 85 combinations of building characteristics for the region ''West''. The uncertainties for the probability of exceeding a threshold were estimated from the data with bootstrapping. The importance of different building characteristics for the presence of enhanced radon concentrations can be predicted from the results of this estimation. Therefore, targeting of affected buildings is possible on this basis. Regional prognoses of exceeding probabilities for building types with high presence can also be created by the use of transfer factors. A Strategy to reduce the health risk from radon in the long run might be derived, where alongside the delineation of radon prone areas, special attention should be paid to a set out building characteristics, also outside the radon prone areas.

  6. Thermodynamics of Highly Concentrated Aqueous Electrolytes: Based on Boltzmann's eponymous equation

    Energy Technology Data Exchange (ETDEWEB)

    Ally, Moonis Raza [ORNL

    2018-05-01

    This sharply focused book invites the reader to explore the chemical thermodynamics of highly concentrated aqueous electrolytes from a different vantage point than traditional methods. The book's foundation is deeply rooted in Ludwig Boltzmann's eponymous equation. The pathway from micro to macro thermodynamics is explained heuristically, in a step-by-step approach. Concepts and mathematical formalism are explained in detail to captivate and maintain interest as the algebra twists and turns. Every significant result is derived in a lucid and piecemeal fashion. Application of the theory is exemplified with examples. It is amazing to realize that Boltamann's simple equation contains sufficient information from which such an elaborate theory can emerge. This book is suitable for undergraduate and graduate level classes in chemical engineering, chemistry, geochemistry, environmental sciences, and those studying aerosol particles in the troposphere. Students interested in understanding how thermodynamic theories may be developed would be inspired by the methodology. The author wishes that readers get as much excitement reading this book as he did writing it.

  7. Determination of radionuclide concentrations in ground level air using the ASS-500 high volume sampler

    International Nuclear Information System (INIS)

    Frenzel, E.; Arnold, D.; Wershofen, H.

    1996-01-01

    A method for determination of radionuclide concentrations in air aerosol samples collected by the high volume aerosol sampler ASS-500 was elaborated. The aerosol sampling station ASS-500 is a Stand alone, all-weather proofed instrument. It is designed for representative sampling of airborne radionuclides from ground level air at a height of about 1.5 m above ground level. The ASS-500 station enables continuous air monitoring both normal and emergency Situations. The collection of aerosols on the Petrianov FPP-15-1.5 type filter out of an air volume of about 100,000 m 3 (sampling period 1 wk) or of about 250,000 m 3 (sampling period 3 wk) admits accurate spectrometric low level measurements of natural and artificial radionuclides. The achieved detection limit is 0.5 μBq m -3 and 0.2 μBq m -3 for 137 Cs, respectively. A new developed air flow Meter system allows to enhance the collected air volume to about 150,000 m 3 per week and lowers the detection limit to -3 for 137 Cs for weekly collected aerosol samples. In Poland the CLOR uses 9 Stations ASS-500 at different sites as atmospheric radioactivity control system. On the basis of spectrometric measurements of natural and artificial radionuclides in the collected aerosol samples at the different sites, CLOR establishes a weekly report about the radiological situation at Poland for responsible authorities. The very low achievable detection limit of the Station ASS-500 due 10 the high air flow fate and the long possible sampling period were the key argument for other government radiation protection authorities in Europe to introduce the Station ASS-500 into their low level radionuclide atmospheric monitoring programs (Austria, Belarus, France, Germany, Iceland, Spain, Switzerland, Ukraine)

  8. Feeding a high-concentrate corn straw diet induced epigenetic alterations in the mammary tissue of dairy cows.

    Directory of Open Access Journals (Sweden)

    Guozhong Dong

    Full Text Available The objective of this study was to investigate the effects of feeding a high-concentrate corn straw (HCS diet (65% concentrate+35% corn straw on the epigenetic changes in the mammary tissue of dairy cows in comparison with a low-concentrate corn straw (LCS diet (46% concentrate+54% corn straw and with a low-concentrate mixed forage (LMF diet (46% concentrate+54% mixed forage.Multiparous mid-lactation Chinese Holstein cows were fed one of these three diets for 6 weeks, at which time blood samples and mammary tissue samples were collected. Mammary arterial and venous blood samples were analyzed for lipopolysaccharide (LPS concentrations while mammary tissue samples were assayed for histone H3 acetylation and the methylation of specific genes associated with fat and protein synthesis.Extraction of histones and quantification of histone H3 acetylation revealed that acetylation was significantly reduced in cows fed the HCS diet, as compared with cows fed the LCS diet. Cows fed the HCS diet had significantly higher LPS concentrations in the mammary arterial blood, as compared with cows fed the LCS diet. We found that the extent of histone H3 acetylation was negatively correlated with LPS concentrations. The methylation of the stearoyl-coenzyme A desaturase gene associated with milk fat synthesis was increased in cows fed the HCS diet. By contrast, methylation of the gene encoding the signal transducer and activator of transcription 5A was reduced in cows fed the HCS diet, suggesting that feeding a high-concentrate corn straw diet may alter the methylation of specific genes involved in fat and protein synthesis in the mammary tissue of dairy cows.Feeding the high-concentrate diet induced epigenetic changes in the mammary tissues of dairy cows, possibly through effecting the release of differing amounts of LPS into the mammary blood.

  9. 15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH.

    Science.gov (United States)

    Shchepin, Roman V; Barskiy, Danila A; Coffey, Aaron M; Theis, Thomas; Shi, Fan; Warren, Warren S; Goodson, Boyd M; Chekmenev, Eduard Y

    2016-06-24

    15 N nuclear spins of imidazole- 15 N 2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15 N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole- 15 N 2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15 N site of imidazole occurs at physiological pH (p K a ∼ 7.0), and the binding event changes the 15 N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. 15 N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.

  10. Facilitated Anion Transport Induces Hyperpolarization of the Cell Membrane That Triggers Differentiation and Cell Death in Cancer Stem Cells.

    Science.gov (United States)

    Soto-Cerrato, Vanessa; Manuel-Manresa, Pilar; Hernando, Elsa; Calabuig-Fariñas, Silvia; Martínez-Romero, Alicia; Fernández-Dueñas, Víctor; Sahlholm, Kristoffer; Knöpfel, Thomas; García-Valverde, María; Rodilla, Ananda M; Jantus-Lewintre, Eloisa; Farràs, Rosa; Ciruela, Francisco; Pérez-Tomás, Ricardo; Quesada, Roberto

    2015-12-23

    Facilitated anion transport potentially represents a powerful tool to modulate various cellular functions. However, research into the biological effects of small molecule anionophores is still at an early stage. Here we have used two potent anionophore molecules inspired in the structure of marine metabolites tambjamines to gain insight into the effect induced by these compounds at the cellular level. We show how active anionophores, capable of facilitating the transmembrane transport of chloride and bicarbonate in model phospholipid liposomes, induce acidification of the cytosol and hyperpolarization of plasma cell membranes. We demonstrate how this combined effect can be used against cancer stem cells (CSCs). Hyperpolarization of cell membrane induces cell differentiation and loss of stemness of CSCs leading to effective elimination of this cancer cell subpopulation.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  12. III-V/Active-Silicon Integration for Low-Cost High-Performance Concentrator Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Ringel, Steven [The Ohio State Univ., Columbus, OH (United States); Carlin, John A [The Ohio State Univ., Columbus, OH (United States); Grassman, Tyler [The Ohio State Univ., Columbus, OH (United States)

    2018-04-17

    This FPACE project was motivated by the need to establish the foundational pathway to achieve concentrator solar cell efficiencies greater than 50%. At such an efficiency, DOE modeling projected that a III-V CPV module cost of $0.50/W or better could be achieved. Therefore, the goal of this project was to investigate, develop and advance a III-V/Si mulitjunction (MJ) CPV technology that can simultaneously address the primary cost barrier for III-V MJ solar cells while enabling nearly ideal MJ bandgap profiles that can yield efficiencies in excess of 50% under concentrated sunlight. The proposed methodology was based on use of our recently developed GaAsP metamorphic graded buffer as a pathway to integrate unique GaAsP and Ga-rich GaInP middle and top junctions having bandgaps that are adjustable between 1.45 – 1.65 eV and 1.9 – 2.1 eV, respectively, with an underlying, 1.1 eV active Si subcell/substrate. With this design, the Si can be an active component sub-cell due to the semi-transparent nature of the GaAsP buffer with respect to Si as well as a low-cost alternative substrate that is amenable to scaling with existing Si foundry infrastructure, providing a reduction in materials cost and a low cost path to manufacturing at scale. By backside bonding of a SiGe, a path to exceed 50% efficiency is possible. Throughout the course of this effort, an expansive range of new understanding was achieved that has stimulated worldwide efforts in III-V/Si PV R&D that spanned materials development, metamorphic device optimization, and complete III-V/Si monolithic integration. Highlights include the demonstration of the first ideal GaP/Si interfaces grown by industry-standard MOCVD processes, the first high performance metamorphic tunnel junctions designed for III-V/Si integration, record performance of specific metamorphic sub-cell designs, the first fully integrated GaInP/GaAsP/Si double (1.7 eV/1.1 eV) and triple (1.95 eV/1.5 eV/1.1 eV) junction solar cells, the first

  13. Concentration of bisphenol A in highly consumed canned foods on the U.S. market.

    Science.gov (United States)

    Noonan, Gregory O; Ackerman, Luke K; Begley, Timothy H

    2011-07-13

    Metal food and drink cans are commonly coated with epoxy films made from phenolic polymers produced from bisphenol A (BPA). It is well established that residual BPA monomer migrates into can contents during processing and storage. While a number of studies have reported BPA concentrations in foods from foreign markets and specialty foods on the U.S. market, very few peer-reviewed data for the BPA concentrations in canned food from the U.S. market were available. This study quantified BPA concentrations in 78 canned and two frozen food products from the U.S. market using an adaptation of a previously reported liquid chromatography-tandem mass spectrometry method. The tested products represented 16 different food types that are from the can food classifications that constitute approximately 65% of U.S. canned food sales and canned food consumption. BPA was detected in 71 of the 78 canned food samples but was not detected in either of the two frozen food samples. Detectable BPA concentrations across all foods ranged from 2.6 to 730 ng/g. Large variations in BPA concentrations were found between different products of the same food type and between different lots of the same product. Given the large concentration ranges, the only distinguishable trend was that fruits and tuna showed the lowest BPA concentrations. Experiments with fortified frozen vegetables and brine solutions, as well as higher BPA concentrations in canned food solids over liquid portions, clearly indicated that BPA partitions into the solid portion of foods.

  14. Effect of low-fat diets on plasma high-density lipoprotein concentrations

    NARCIS (Netherlands)

    Katan, M.B.

    1998-01-01

    Low concentrations of HDLs in plasma are a strong predictor of risk for coronary as well as other cardiovascular diseases. There is increasing evidence that this relation is causal and that interventions that change HDL concentrations also change risk. One such intervention is exchanging fat and

  15. Hyperpolarized 13C-Urea MRI for the assessment of the urea gradient in the porcine kidney

    DEFF Research Database (Denmark)

    Søvsø Szocska Hansen, Esben; Stewart, Neil James; Wild, Jim Michael

    Renal anatomical and pathophysiological alterations are directly associated with the fluid and electrolyte balance in the kidney, which is regulated by the extracellular corticomedullary osmolality gradient. We introduce a novel magnetic resonance imaging (MRI) approach to monitor...... treatment resulted in an increased urea accumulation in the cortical space. This work demonstrates intra-renal functional assessment with hyperpolarized 13C-urea MRI in multi-papillary kidneys....

  16. Direct hyperpolarization of micro- and nanodiamonds for bioimaging applications - Considerations on particle size, functionalization and polarization loss

    Science.gov (United States)

    Kwiatkowski, Grzegorz; Jähnig, Fabian; Steinhauser, Jonas; Wespi, Patrick; Ernst, Matthias; Kozerke, Sebastian

    2018-01-01

    Due to the inherently long relaxation time of 13C spins in diamond, the nuclear polarization enhancement obtained with dynamic nuclear polarization can be preserved for a time on the order of about one hour, opening up an opportunity to use diamonds as a new class of long-lived contrast agents. The present communication explores the feasibility of using 13C spins in directly hyperpolarized diamonds for MR imaging including considerations for potential in vivo applications.

  17. Integrated B1+ Mapping for Hyperpolarized 13C MRI in a Clinical Setup using Multi-Channel Receive Arrays

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Shin, Peter J.; Gordon, Jeremy W.

    inhomogeneous transmit coils, and because kinetic modeling based on incorrect flip angles can lead to incorrect rate constant estimations. This study demonstrates the feasibility of integrated B1+ mapping for large volume thermal and hyperpolarized phantoms in a clinical setup using a clamshell transmit coil...... and a 16-channel receive array, and a 3D stack-of-spirals sequence. Phase-sensitive coil-combination was achieved using ESPIRiT....

  18. The Copper concentration variation to physical properties of high copper amalgam alloy

    Directory of Open Access Journals (Sweden)

    Aminatun Aminatun

    2006-09-01

    Full Text Available The function of copper (Cu inside amalgam is to increase hardness and impact force and to decrease thermal expansion coefficient. In general, amalgam which is used in dentistry and available in the market is contain Cu 22%, while the maximum Cu concentration is 30%. It is necessary to determine the concentration Cu does generate the best physical properties to be used as dental restorative agent. Amalgam is made by mixing blended-metal Ag-Sn-Cu (with Cu concentration of 13%, 21%, 22%, and 29% and Hg, stirred manually in a bowl for 15 minutes,leave it in temperature 27°C for 24 hours to become hardened. The result of X-Ray Diffractometer (XRD, analyzed by Rietveld method and Rietica program, shows amalgam with Cu 29% concentration for Cu3Sn compound density is 31.790 sma/Å3, for Ag2Hg3 compound is 41.733 sma/ Å3, a Cu3Sn relative weight percentage of 43.23%, Ag2Hg3 of 54.54%, Cu 7Hg6 of 2.23% and hardness of Cu 29% is 90.700 ± 0.005 kgf/mm2. These numbers are the highest values on Cu 29% concentrations compared to other copper concentration variants. Whereas amalgam thermal expansion coefficient on Cu 29% is (2.17 ± 0.9110-3 mm/°C is the lowest value compared to other Cu concentration. The conclution is that adding Cu concentration into amalgam will increase density value, Cu3Sn relative weight percentage, hardness level and will decrease amalgam thermal expansion coefficient. Amalgam 29% Cu concentration has better physical properties compared to amalgam Cu 22% concentration.

  19. Diet-induced obesity impairs endothelium-derived hyperpolarization via altered potassium channel signaling mechanisms.

    Directory of Open Access Journals (Sweden)

    Rebecca E Haddock

    Full Text Available BACKGROUND: The vascular endothelium plays a critical role in the control of blood flow. Altered endothelium-mediated vasodilator and vasoconstrictor mechanisms underlie key aspects of cardiovascular disease, including those in obesity. Whilst the mechanism of nitric oxide (NO-mediated vasodilation has been extensively studied in obesity, little is known about the impact of obesity on vasodilation to the endothelium-derived hyperpolarization (EDH mechanism; which predominates in smaller resistance vessels and is characterized in this study. METHODOLOGY/PRINCIPAL FINDINGS: Membrane potential, vessel diameter and luminal pressure were recorded in 4(th order mesenteric arteries with pressure-induced myogenic tone, in control and diet-induced obese rats. Obesity, reflecting that of human dietary etiology, was induced with a cafeteria-style diet (∼30 kJ, fat over 16-20 weeks. Age and sexed matched controls received standard chow (∼12 kJ, fat. Channel protein distribution, expression and vessel morphology were determined using immunohistochemistry, Western blotting and ultrastructural techniques. In control and obese rat vessels, acetylcholine-mediated EDH was abolished by small and intermediate conductance calcium-activated potassium channel (SK(Ca/IK(Ca inhibition; with such activity being impaired in obesity. SK(Ca-IK(Ca activation with cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl-6-methyl-pyrimidin-4-yl]-amine (CyPPA and 1-ethyl-2-benzimidazolinone (1-EBIO, respectively, hyperpolarized and relaxed vessels from control and obese rats. IK(Ca-mediated EDH contribution was increased in obesity, and associated with altered IK(Ca distribution and elevated expression. In contrast, the SK(Ca-dependent-EDH component was reduced in obesity. Inward-rectifying potassium channel (K(ir and Na(+/K(+-ATPase inhibition by barium/ouabain, respectively, attenuated and abolished EDH in arteries from control and obese rats, respectively; reflecting differential K

  20. High concentrations of coarse particles emitted from a cattle feeding operation

    Directory of Open Access Journals (Sweden)

    N. Hiranuma

    2011-08-01

    Full Text Available Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS and a GRIMM Portable Aerosol Spectrometer (PAS, were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less were as high as 1200 μg m−3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health.

  1. Photo-oxidation of histidine peptides yields high concentrations of unstable peroxides

    International Nuclear Information System (INIS)

    Policarpio, V.V.; Hawkins, C.L.; Davies, M.J.

    2003-01-01

    Oxidation of proteins by UV, and visible light in the presence of sensitizers, results in side chain modification as well as aggregation and fragmentation. In particular, singlet oxygen has been reported to oxidize Met, Trp, Tyr, Cys and His side chains in a selective manner. In this study the oxidation of histidine and its derivatives, and His-containing peptides is examined using a range of sensitizers, to determine whether peroxides are major intermediates, and the mechanism of formation of these species. Visible light-sensitised oxidation of Gly-His-Gly in the presence of oxygen and rose bengal gives unstable substrate-derived peroxides with the peroxide yield increasing with increasing photolysis time. Similar behaviour was detected with other photosensitizers, though the peroxide yields varied with the sensitizer at identical concentrations with rose bengal > aluminium phthalocyanine > hematoporphyrin IX > zinc phthalocyanine > tetrakisporphine. The peroxide yield was decreased in the presence of azide and enhanced when deuterium oxide was employed as the solvent, consistent with peroxide formation being singlet oxygen mediated. Experiments using anoxic conditions gave low yields of peroxides confirming the oxygen-dependence of these reactions. HPLC analysis showed rapid loss of the parent peptide, with subsequent formation of both stable and unstable products; these are currently being characterized by MS and NMR. Similar behavior has been observed with other His derivatives. The yield of singlet oxygen formed in these reactions has been estimated using a bleaching assay (N, N-dimethyl-4-nitrosoaniline). Quantification of singlet oxygen formation and Gly-His-Gly derived peroxide during rose bengal-mediated photooxidation indicated a conversion efficiency of the initial singlet oxygen into substrate-derived peroxides of ca. 75% indicating that peroxide formation is a highly efficient and major reaction pathway

  2. High-frequency productivity estimates for a lake from free-water CO2 concentration measurements

    Science.gov (United States)

    Provenzale, Maria; Ojala, Anne; Heiskanen, Jouni; Erkkilä, Kukka-Maaria; Mammarella, Ivan; Hari, Pertti; Vesala, Timo

    2018-04-01

    Lakes are important actors in biogeochemical cycles and a powerful natural source of CO2. However, they are not yet fully integrated in carbon global budgets, and the carbon cycle in the water is still poorly understood. In freshwater ecosystems, productivity studies have usually been carried out with traditional methods (bottle incubations, 14C technique), which are imprecise and have a poor temporal resolution. Consequently, our ability to quantify and predict the net ecosystem productivity (NEP) is limited: the estimates are prone to errors and the NEP cannot be parameterised from environmental variables. Here we expand the testing of a free-water method based on the direct measurement of the CO2 concentration in the water. The approach was first proposed in 2008, but was tested on a very short data set (3 days) under specific conditions (autumn turnover); despite showing promising results, this method has been neglected by the scientific community. We tested the method under different conditions (summer stratification, typical summer conditions for boreal dark-water lakes) and on a much longer data set (40 days), and quantitatively validated it comparing our data and productivity models. We were able to evaluate the NEP with a high temporal resolution (minutes) and found a very good agreement (R2 ≥ 0.71) with the models. We also estimated the parameters of the productivity-irradiance (PI) curves that allow the calculation of the NEP from irradiance and water temperature. Overall, our work shows that the approach is suitable for productivity studies under a wider range of conditions, and is an important step towards developing this method so that it becomes more widely used.

  3. High-frequency productivity estimates for a lake from free-water CO2 concentration measurements

    Directory of Open Access Journals (Sweden)

    M. Provenzale

    2018-04-01

    Full Text Available Lakes are important actors in biogeochemical cycles and a powerful natural source of CO2. However, they are not yet fully integrated in carbon global budgets, and the carbon cycle in the water is still poorly understood. In freshwater ecosystems, productivity studies have usually been carried out with traditional methods (bottle incubations, 14C technique, which are imprecise and have a poor temporal resolution. Consequently, our ability to quantify and predict the net ecosystem productivity (NEP is limited: the estimates are prone to errors and the NEP cannot be parameterised from environmental variables. Here we expand the testing of a free-water method based on the direct measurement of the CO2 concentration in the water. The approach was first proposed in 2008, but was tested on a very short data set (3 days under specific conditions (autumn turnover; despite showing promising results, this method has been neglected by the scientific community. We tested the method under different conditions (summer stratification, typical summer conditions for boreal dark-water lakes and on a much longer data set (40 days, and quantitatively validated it comparing our data and productivity models. We were able to evaluate the NEP with a high temporal resolution (minutes and found a very good agreement (R2 ≥ 0.71 with the models. We also estimated the parameters of the productivity–irradiance (PI curves that allow the calculation of the NEP from irradiance and water temperature. Overall, our work shows that the approach is suitable for productivity studies under a wider range of conditions, and is an important step towards developing this method so that it becomes more widely used.

  4. High concentrations of coarse particles emitted from a cattle feeding operation

    Science.gov (United States)

    Hiranuma, N.; Brooks, S. D.; Gramann, J.; Auvermann, B. W.

    2011-08-01

    Housing roughly 10 million head of cattle in the United States alone, open air cattle feedlots represent a significant but poorly constrained source of atmospheric particles. Here we present a comprehensive characterization of physical and chemical properties of particles emitted from a large representative cattle feedlot in the Southwest United States. In the summer of 2008, measurements and samplings were conducted at the upwind and downwind edges of the facility. A series of far-field measurements and samplings was also conducted 3.5 km north of the facility. Two instruments, a GRIMM Sequential Mobility Particle Sizer (SMPS) and a GRIMM Portable Aerosol Spectrometer (PAS), were used to measure particle size distributions over the range of 0.01 to 25 μm diameter. Raman microspectroscopy was used to determine the chemical composition of particles on a single particle basis. Volume size distributions of dust were dominated by coarse mode particles. Twenty-four hour averaged concentrations of PM10 (particulate matter with a diameter of 10 μm or less) were as high as 1200 μg m-3 during the campaign. The primary constituents of the particulate matter were carbonaceous materials, such as humic acid, water soluble organics, and less soluble fatty acids, including stearic acid and tristearin. A significant fraction of the organic particles was present in internal mixtures with salts. Basic characteristics such as size distribution and composition of agricultural aerosols were found to be different than the properties of those found in urban and semi-urban aerosols. Failing to account for such differences may lead to errors in estimates of aerosol effects on local air quality, visibility, and public health.

  5. Effect of high calcium concentration influents on enhanced biological phosphorus removal process

    International Nuclear Information System (INIS)

    Montoya Martinez, T.; Aguado Garcia, D.; Ferrer Polo, J.

    2010-01-01

    In this work, the effect of calcium concentration in wastewater on the polyphosphate accumulating organisms (PAO) is investigated as well as its influence in PAO metabolism, specifically in the Y P O4 (ratio between phosphorus release and acetic acid uptake). For this study a sequencing batch reactor (SBR) anaerobic-aerobic was used, in which the PAO enriched biomass was exposed to different calcium concentrations in the influent wastewater. The results indicate that until a given calcium level in the influent wastewater (35 mg Ca/l) the metabolism is not affect, but higher calcium concentrations lead to significant Y P O4 decline. (Author) 18 refs.

  6. Highly Sensitive Multi-Channel IDC Sensor Array for Low Concentration Taste Detection

    Directory of Open Access Journals (Sweden)

    Md. Rajibur Rahaman Khan

    2015-06-01

    Full Text Available In this study, we designed and developed an interdigitated capacitor (IDC-based taste sensor array to detect different taste substances. The designed taste sensing array has four IDC sensing elements. The four IDC taste sensing elements of the array are fabricated by incorporating four different types of lipids into the polymer, dioctyl phenylphosphonate (DOPP and tetrahydrofuran (THF to make the respective dielectric materials that are individually placed onto an interdigitated electrode (IDE via spin coating. When the dielectric material of an IDC sensing element comes into contact with a taste substance, its dielectric properties change with the capacitance of the IDC sensing element; this, in turn, changes the voltage across the IDC, as well as the output voltage of each channel of the system. In order to assess the effectiveness of the sensing system, four taste substances, namely sourness (HCl, saltiness (NaCl, sweetness (glucose and bitterness (quinine-HCl, were tested. The IDC taste sensor array had rapid response and recovery times of about 12.9 s and 13.39 s, respectively, with highly stable response properties. The response property of the proposed IDC taste sensor array was linear, and its correlation coefficient R2 was about 0.9958 over the dynamic range of the taste sensor array as the taste substance concentration was varied from 1 μM to 1 M. The proposed IDC taste sensor array has several other advantages, such as real-time monitoring capabilities, high sensitivity 45.78 mV/decade, good reproducibility with a standard deviation of about 0.029 and compactness, and the circuitry is based on readily available and inexpensive electronic components. The proposed IDC taste sensor array was compared with the potentiometric taste sensor with respect to sensitivity, dynamic range width, linearity and response time. We found that the proposed IDC sensor array has better performance. Finally, principal component analysis (PCA was applied

  7. Effect of high Xe-concentration in a plasma display panel with a SrCaO cold cathode

    International Nuclear Information System (INIS)

    Uchida, Giichiro; Kajiyama, Hiroshi; Shinoda, Tsutae; Uchida, Satoshi; Akiyama, Toshiyuki

    2010-01-01

    We present here measurements of high Xe-contents plasma display panel (PDP) with SrCaO cold cathode. Luminous efficacy (η) shows a two-step increase with Xe-concentration in Ne/Xe gas mixture: η drastically increases up to Xe-concentration of 30% (Xe: 30%), and then attains 5 lm/W at the highest Xe-concentration of Xe: 100%. The high performance PDP with Xe: 100% can be operated at low applied voltage between 230 and 377 V due to the high secondary electron emission from the SrCaO cathode. Emission measurements clearly show the change in discharge characteristics at Xe: 30%, where the discharge changes from a Ne/Xe mixture discharge to an almost pure Xe discharge, and the vacuum ultraviolet (VUV) radiation from the combination of resonance and excimer radiations to only excimer radiation. Theoretical analysis solving Boltzmann equation for electron demonstrates that increasing Xe-concentration enhances the collision frequency for electron impact excitation directly from ground state to lower levels concerned with the VUV radiation, resulting in a drastic increase in luminous efficacy up to Xe: 30%. Also, one-dimensional fluid simulation of a Ne/Xe dielectric barrier discharge clearly shows that a combination of high secondary electron emission cathode and high Xe-concentration is quite effective for high VUV radiation efficiency because it induces a drastic increase in electron-heating efficiency.

  8. High concentration of Daunorubicin and Daunorubicinol in human malignant astrocytomas after systemic administration of liposomal Daunorubicin

    NARCIS (Netherlands)

    Albrecht, K. W.; de Witt Hamer, P. C.; Leenstra, S.; Bakker, P. J.; Beijnen, J. H.; Troost, D.; Kaaijk, P.; Bosch, A. D.

    2001-01-01

    The value of chemotherapy in patients with malignant astrocytoma remains controversial. In our laboratories in vitro experiments with organotypic spheroid cultures showed superior effectiveness of anthracyclines. Systemic administration did not provide in therapeutic concentrations so far. Because

  9. Sustained high serum caspase-3 concentrations and mortality in septic patients.

    Science.gov (United States)

    Lorente, L; Martín, M M; Pérez-Cejas, A; González-Rivero, A F; López, R O; Ferreres, J; Solé-Violán, J; Labarta, L; Díaz, C; Palmero, S; Jiménez, A

    2018-02-01

    Caspase-3 is the main executor of the apoptotic process. Higher serum caspase-3 concentrations in non-survivor compared to survivor septic patients have been found. The objectives of this work (with the increase of sample size to 308 patients, and the determination of serum caspase-3 concentrations also on days 4 and 8 of diagnosis of severe sepsis) were to know whether an association between serum caspase-3 concentrationss during the first week, degree of apoptosis, sepsis severity, and sepsis mortality exists. We collected serum samples of 308 patients with severe sepsis from eight intensive care units on days 1, 4 and 8 to measure concentrations of caspase-3 and caspase-cleaved cytokeratin (CCCK)-18 (to assess degree of apoptosis). End point was 30-day mortality. We found higher serum concentrations of caspase-3 and CCCK-18 in non-survivors compared to survivors on days 1 (p < 0.001), 4 (p < 0.001), and 8 (p < 0.001). We found an association between serum caspase-3 concentrations on days 1, 4 and 8 of severe sepsis diagnosis and serum CCCK-18 concentrations (p < 0.001), SOFA (p < 0.001), serum acid lactic concentrations (p < 0.001), and 30-day sepsis mortality (p < 0.001). The new findings of this work were that an association between serum caspase-3 concentrations during the first week, apoptosis degree, sepsis severity, and sepsis mortality exists.

  10. Serum vitamin E concentrations among highly functioning hip fracture patients are higher than in nonfracture controls

    OpenAIRE

    D’Adamo, Christopher R.; Shardell, Michelle D.; Hicks, Gregory E.; Orwig, Denise L.; Hochberg, Marc C.; Semba, Richard D.; Yu-Yahiro, Janet A.; Ferrucci, Luigi; Magaziner, Jay S.; Miller, Ram R.

    2011-01-01

    Malnutrition after hip fracture is common and associated with poor outcomes and protracted recovery. Low concentrations of vitamin E have been associated with incident decline in physical function among older adults and may, therefore, be particularly important to functionally compromised patients hip fracture patients. Serum concentrations of α-tocopherol and γ-tocopherol, the 2 major forms of vitamin E, were assessed in 148 female hip fracture patients 65 years or older from the Baltimore H...

  11. Honeybee males use highly concentrated nectar as fuel for mating flights.

    Science.gov (United States)

    Hayashi, Masaki; Nakamura, Jun; Sasaki, Ken; Harano, Ken-Ichi

    Honeybees use nectar held in the crop as their main source of energy for flight but the mass of the crop nectar load may be a cost burden. This study investigated whether males of the honeybee Apis mellifera adjust their nectar fuel load and concentration to enhance the success of mating flights. When the crop content was compared between males staying in the hive and those departing, the latter group had the larger volume (median, 5.0μl; range, 0.0-17.8μl) and higher concentration (median, 71.6%; range, 49.0%-77.6%), indicating that departing males load concentrated nectar as fuel before mating flights. Moreover, the crop nectar concentration was significantly higher in departing males than in departing workers. These results suggest that concentrated nectar is advantageous to males because it provides more sugar for energy at lower mass and secures longer or more effective mating flights for higher chance of reproductive success. No significant effect of age was detected in crop volume, and concentration and amount of dissolved sugars in the crop content. In addition, laboratory experiments showed that males had only about 5μl of nectar in the crop soon after feeding, irrespective of fed volume (5-15μl), suggesting they do not hold much nectar in the crop but send it rapidly to the midgut, unlike workers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. High Concentration of Heat Pumps in Suburban Areas and Reduction of Their Impact on the Electricity Network

    NARCIS (Netherlands)

    Pruissen, O.P. van; Kamphuis, I.G.

    2011-01-01

    One of the challenges of the near future for a more renewable Dutch electricity infrastructure is the embedding of high concentrations of heat pumps in currently built domestic residences. In the Dutch situation demand of electricity occurs simultaneously with demand of heat, high electricity peak

  13. Conformational Analysis of Proteins in Highly Concentrated Solutions by Dialysis-Coupled Hydrogen/Deuterium Exchange Mass Spectrometry

    DEFF Research Database (Denmark)

    Houde, Damian; Esmail Nazari, Zeinab; Bou-Assaf, George M

    2016-01-01

    When highly concentrated, an antibody solution can exhibit unusual behaviors, which can lead to unwanted properties, such as increased levels of protein aggregation and unusually high viscosity. Molecular modeling, along with many indirect biophysical measurements, has suggested that the cause fo...... in industry. Graphical Abstract ᅟ....

  14. The effect of extremely high glucose concentrations on 21 routine chemistry and thyroid Abbott assays: interference study.

    Science.gov (United States)

    Çuhadar, Serap; Köseoğlu, Mehmet; Çinpolat, Yasemin; Buğdaycı, Güler; Usta, Murat; Semerci, Tuna

    2016-01-01

    Extremely high glucose concentrations have been shown to interfere with creatinine assays especially with Jaffe method in peritoneal dialysate. Because diabetes is the fastest growing chronic disease in the world, laboratories study with varying glucose concentrations. We investigated whether different levels of glucose spiked in serum interfere with 21 routine chemistry and thyroid assays at glucose concentrations