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Sample records for radiotracer efficiency study

  1. Monoamine oxidase: Radiotracer chemistry and human studies

    DOE PAGESBeta

    Fowler, Joanna S.; Logan, Jean; Shumay, Elena; Alia-Klein, Nelly; Wang, Gene-Jack; Volkow, Nora D.

    2015-03-01

    Monoamine oxidase (MAO) oxidizes amines from both endogenous and exogenous sources thereby regulating the concentration of neurotransmitter amines such as serot onin, norepinephrine and dopamine as well as many xenobiotics. MAO inhibitor drugs are used in the treatment of Parkinson’s disease and in depression stimulating the development of radiotracer tools to probe the role of MAO in normal human biology and in disease. Over the past 30 since the first radiotracers were developed and the first PET images of MAO in humans were carried out, PET studies of brain MAO in healthy volunteers and in patients have identified different variablesmore » which have contributed to different MAO levels in brain and in peripheral organs. MAO radiotracers and PET have also been used to study the current and developing MAO inhibitor drugs including the selection of doses for clinical trials. In this article, we describe (1) the development of MAO radiotracers; (2) human studies including the relationship of brain MAO levels to genotype, personality, neurological and psychiatric disorders; (3) examples of the use of MAO radiotracers in drug research and development. We will conclude with outstanding needs to improve the radiotracers which are currently used and possible new applications.« less

  2. Monoamine oxidase: Radiotracer chemistry and human studies

    SciTech Connect

    Fowler, Joanna S.; Logan, Jean; Shumay, Elena; Alia-Klein, Nelly; Wang, Gene-Jack; Volkow, Nora D.

    2015-03-01

    Monoamine oxidase (MAO) oxidizes amines from both endogenous and exogenous sources thereby regulating the concentration of neurotransmitter amines such as serot onin, norepinephrine and dopamine as well as many xenobiotics. MAO inhibitor drugs are used in the treatment of Parkinson’s disease and in depression stimulating the development of radiotracer tools to probe the role of MAO in normal human biology and in disease. Over the past 30 since the first radiotracers were developed and the first PET images of MAO in humans were carried out, PET studies of brain MAO in healthy volunteers and in patients have identified different variables which have contributed to different MAO levels in brain and in peripheral organs. MAO radiotracers and PET have also been used to study the current and developing MAO inhibitor drugs including the selection of doses for clinical trials. In this article, we describe (1) the development of MAO radiotracers; (2) human studies including the relationship of brain MAO levels to genotype, personality, neurological and psychiatric disorders; (3) examples of the use of MAO radiotracers in drug research and development. We will conclude with outstanding needs to improve the radiotracers which are currently used and possible new applications.

  3. Radiotracers for PET and SPECT studies of neurotransmitter systems

    SciTech Connect

    Fowler, J.S.

    1991-01-01

    The study of neurotransmitter systems is one of the major thrusts in emission tomography today. The current generation of Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) radiotracers examines neurotransmitter properties from a number of different perspectives including their pre and post synaptic sites and the activity of the enzymes which regulate their concentration. Although the dopamine system has been the most extensively investigated, other neurotransmitter systems including the acetylcholine muscarine, serotonin, benzodiazepine, opiate, NMDA and others are also under intensive development. Enzymes involved in the synthesis and regulation of neurotransmitter concentration, for example monoamine oxidase and amino acid decarboxylase has also been probed in vivo. Medical applications range from the study of normal function and the characterization of neurotransmitter activity in neurological and psychiatric diseases and in heart disease and cancer to the study of the binding of therapeutic drugs and substances of abuse. This chapter will provide an overview of the current generation of radiotracers for PET and SPECT studies of neurotransmitter systems including radiotracer design, synthesis localization mechanisms and applications in emission tomography. 60 refs., 1 tab.

  4. MONOAMINE OXIDASE: RADIOTRACER DEVELOPMENT AND HUMAN STUDIES.

    SciTech Connect

    FOWLER,J.S.; LOGAN,J.; VOLKOW,N.D.; WANG,G.J.; MACGREGOR,R.R.; DING,Y.S.

    2000-09-28

    PET is uniquely capable of providing information on biochemical transformations in the living human body. Although most of the studies of monoamine oxidase (MAO) have focused on measurements in the brain, the role of peripheral MAO as a phase 1 enzyme for the metabolism of drugs and xenobiotics is gaining attention (Strolin Benedetti and Tipton, 1998; Castagnoli et al., 1997.). MAO is well suited for this role because its concentration in organs such as kidneys, liver and digestive organs is high sometimes exceeding that in the brain. Knowledge of the distribution of the MAO subtypes within different organs and different cells is important in determining which substrates (and which drugs and xenobiotics) have access to which MAO subtypes. The highly variable subtype distribution with different species makes human studies even more important. In addition, the deleterious side effects of combining MAO inhibitors with other drugs and with foodstuffs makes it important to know the MAO inhibitory potency of different drugs both in the brain and in peripheral organs (Ulus et al., 2000). Clearly PET can play a role in answering these questions, in drug research and development and in discovering some of the factors which contribute to the highly variable MAO levels in different individuals.

  5. Carbon-11 labeling of CP-126,998*: A radiotracer for in vivo studies of acetylcholinesterase

    SciTech Connect

    Musachio, J.L.; Flesher, J.E.; Scheffel, U.

    1996-05-01

    The study of acetylcholinesterase (AChE) via PET is of interest as reduced activity of this enzyme has been observed in Alzheimer`s disease. Our efforts to develop a radiotracer for mapping of AChE have focused on the N-benzylpiperidine benzisoxazole, CP-126,998, a highly potent (IC{sub 50}=0.48 nm) and selective inhibitor of AChE. High specific activity [C-11] CP-126,998 was synthesized (14 - 24% radiochemical yield, non-decay corrected) by treatment of the desmethyl precursor, CP-118,954, with [C-11] methyl iodide and tetrabutylammonium hydroxide in DMF. In vivo studies with [C-11] CP-126,998 in mice show that this radiotracer displays highest uptake in striatum (6.2 %ID/g), a brain region known to be rich in AChE. The (striatum-cerebellum)/cerebellar radioactivity ratio reached a maximum of 4.3 at 30 min postinjection, and this ratio decreased to 2.4 at 120 min. .Radiotracer binding was saturable in vivo by pretreatment with CP-118,954. Pretreatment of mice with diisopropylfluorophosphate (4 mg/kg i.p.), a known AChE inhibitor, significantly inhibited binding in striatum in a dose-dependent manner. Initial results suggest that [C-11] CP-126,998 may prove useful as a marker for the study of AChE in humans via PET.

  6. RADIOTRACER STUDIES OF INTERACTIONS BETWEEN SEDIMENTS AND FRESHWATER MACROBENTHOS

    EPA Science Inventory

    Gamma-emitting radioiosotopes were used to study the effect of five species of benthic macrofauna, common to the North American Great Lakes, on the movement of solutes and particles in sediments. In a special control cell with worm tubes but no live worms, there was no enhancemen...

  7. In vivo distribution of liposome encapsulated hemoglobin studied with imaging radiotracers. Progress report

    SciTech Connect

    Phillips, W.T.

    1992-12-01

    This project has as its objective the development of radiotracer imaging technology to follow the in vivo circulation and organ deposition of liposome encapsulated hemoglobin (LEH). LEH will be labeled with technetium-99m or indium-111 and infused into small animals to monitor any in vivo differences between different LEH formulations. These studies will be correlated with any hematological and pathological changes associated with LEH treatment. Development of such non-invasive monitoring techniques may lead to significant cost effective manufacturing and formulation improvements, and ultimately a more efficacious LEH product. The development of this elegant labeling technique should make it possible to study the effect of various LEH modifications on biodistribution non-invasively in primates and humans.

  8. A radiotracer study of cerium and manganese uptake onto suspended particles in Chesapeake Bay

    SciTech Connect

    Moffett, J.W. )

    1994-01-01

    The oxidation kinetics of Ce(III) and Mn(II) were studied in Chesapeake Bay in March and July 1990 to establish the role of water column redox processes in contributing to Ce anomalies observed in this estuary (SHOLKOVITZ and ELDERFIELD, 1988; SHOLKOVITZ et al., 1992). Oxidation was measured by adding Mn(II) and Ce(III) to freshly collected water samples as radiotracers and measuring their uptake onto the ambient suspended particle assemblage. Mn(II) oxidation was measured by following the uptake of [sup 54]Mn(II) onto suspended particles and utilizing protocols established by other workers to distinguish oxidation from Mn(II) adsorption. The same protocols were applicable to Ce(III), using [sup 139]Ce(III), and were supported by the use of [sup 152]Eu(III) as a nonredox reactive control. Specific rates of Ce(III) and MN(II) oxidation measured at a station in the North Bay (depth = 4 m) in July were 2016% per day and 4032% per day, respectively. In March, at the same station, the specific rate of Mn(II) of oxidation was only 1-% per day, and Ce(III) oxidation was undetectable. Both Ce(III) and Mn(II) oxidation processes were inhibited by azide, indicating that they were microbially mediated. The seasonal differences probably reflect strong seasonal variation in the abundance of Mn oxidizing bacteria. No Ce(III) oxidation occured in samples collected below the oxic/anoxic interface in July. The specific rates of oxidation for both elements were over 1000 times higher than those measured in the Sargasso Sea. However, the specific rates for Ce(III) and Mn(II) were very similar to each other. This fact, coupled with similar spatial and temporal trends for specific oxidation rates, suggests a common mechanism of oxidation of both elements which may be significant in a wide range of marine environments.

  9. A Philosophy for CNS Radiotracer Design

    PubMed Central

    2015-01-01

    are available to predict bioavailability, blood–brain barrier (BBB) permeability, and the associated issues of nonspecific binding and metabolic stability. To evaluate the synthesized chemical library, researchers need to consider high-throughput affinity assays, the analysis of specific binding, and the importance of fast binding kinetics. Finally, we describe how we initially assess preclinical radiotracer imaging, using brain uptake, specific binding, and preliminary kinetic analysis to identify promising radiotracers that may be useful for human brain imaging. Although we discuss these five design components separately and linearly in this Account, in practice we develop new PET-based radiotracers using these design components nonlinearly and iteratively to develop new compounds in the most efficient way possible. PMID:25272291

  10. Preclinical Comparative Study of (68)Ga-Labeled DOTA, NOTA, and HBED-CC Chelated Radiotracers for Targeting PSMA.

    PubMed

    Ray Banerjee, Sangeeta; Chen, Zhengping; Pullambhatla, Mrudula; Lisok, Ala; Chen, Jian; Mease, Ronnie C; Pomper, Martin G

    2016-06-15

    (68)Ga-labeled, low-molecular-weight imaging agents that target the prostate-specific membrane antigen (PSMA) are increasingly used clinically to detect prostate and other cancers with positron emission tomography (PET). The goal of this study was to compare the pharmacokinetics of three PSMA-targeted radiotracers: (68)Ga-1, using DOTA-monoamide as the chelating agent; (68)Ga-2, containing the macrocyclic chelating agent p-SCN-Bn-NOTA; and (68)Ga-DKFZ-PSMA-11, currently in clinical trials, which uses the acyclic chelating agent, HBED-CC. The PSMA-targeting scaffold for all three agents utilized a similar Glu-urea-Lys-linker construct. Each radiotracer enabled visualization of PSMA+ PC3 PIP tumor, kidney, and urinary bladder as early as 15 min post-injection using small animal PET/computed tomography (PET/CT). (68)Ga-2 demonstrated the fastest rate of clearance from all tissues in this series and displayed higher uptake in PSMA+ PC3 PIP tumor compared to (68)Ga-1 at 1 h post-injection. There was no significant difference in PSMA+ PC3 PIP tumor uptake for the three agents at 2 and 3 h post-injection. (68)Ga-DKFZ-PSMA-11 demonstrated the highest uptake and retention in normal tissues, including kidney, blood, spleen, and salivary glands and PSMA-negative PC3 flu tumors up to 3 h post-injection. In this preclinical evaluation (68)Ga-2 had the most advantageous characteristics for PSMA-targeted PET imaging. PMID:27076393

  11. Improving the In Vivo Profile of Minigastrin Radiotracers: A Comparative Study Involving the Neutral Endopeptidase Inhibitor Phosphoramidon.

    PubMed

    Kaloudi, Aikaterini; Nock, Berthold A; Lymperis, Emmanouil; Krenning, Eric P; de Jong, Marion; Maina, Theodosia

    2016-02-01

    Minigastrin radiotracers, such as [(111)In-DOTA]MG0 ([(111)In-DOTA-DGlu(1)]minigastrin), have been considered for diagnostic imaging and radionuclide therapy of CCK2R-positive human tumors, such as medullary thyroid carcinoma. However, the high kidney retention assigned to the pentaGlu(2-6) repeat in the peptide sequence has compromised their clinical applicability. On the other hand, truncated des(Glu)(2-6)-analogs, such as [(111)In-DOTA]MG11 ([(111)In-DOTA-DGlu(10),desGlu(2-6)]minigastrin), despite their low renal uptake, show poor bioavailability and tumor targeting. [(111)In]CP04 ([(111)In-DOTA-DGlu(1-6)]minigastrin) acquired by Glu(2-6)/DGlu(2-6) substitution showed promising tumor-to-kidney ratios in rodents. In the present study, we compare the biological profiles of [(111)In]CP04, [(111)In-DOTA]MG11, and [(111)In-DOTA]MG0 during in situ neutral endopeptidase (NEP) inhibition, recently shown to improve the bioavailability of several peptide radiotracers. After coinjection of the NEP inhibitor, phosphoramidon (PA), the stability of [(111)In]CP04 and [(111)In-DOTA]MG0 in peripheral mouse blood increased, with an exceptional >14-fold improvement monitored for [(111)In-DOTA]MG11. In line with these findings, PA treatment increased the uptake of [(111)In]CP04 (8.5 ± 0.4%ID/g to 16.0 ± 2.3%ID/g) and [(111)In-DOTA]MG0 (11.9 ± 2.2%ID/g to 17.2 ± 0.9%ID/g) in A431-CCK2R(+) tumors at 4 hours postinjection, whereas the respective increase for [(111)In-DOTA]MG11 was >6-fold (2.5 ± 0.9%ID/g to 15.1 ± 1.7%ID/g). Interestingly, kidney uptake remained lowest for [(111)In-DOTA]MG11, but unfavorably increased by PA treatment for [(111)In-DOTA]MG0. Thus, overall, the most favorable in vivo profile was displayed by [(111)In-DOTA]MG11 during NEP inhibition, highlighting the need to validate this promising concept in the clinic. PMID:26844849

  12. Optimization of integrated impeller mixer via radiotracer experiments.

    PubMed

    Othman, N; Kamarudin, S K; Takriff, M S; Rosli, M I; Engku Chik, E M F; Adnan, M A K

    2014-01-01

    Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, V dead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and V dead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization. PMID:24741344

  13. Optimization of Integrated Impeller Mixer via Radiotracer Experiments

    PubMed Central

    Othman, N.; Kamarudin, S. K.; Takriff, M. S.; Rosli, M. I.; Engku Chik, E. M. F.; Adnan, M. A. K.

    2014-01-01

    Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, Vdead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and Vdead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization. PMID:24741344

  14. Study of ⁷Be and ²¹⁰Pb as radiotracers of African intrusions in Malaga (Spain).

    PubMed

    Gordo, E; Liger, E; Dueñas, C; Fernández, M C; Cañete, S; Pérez, M

    2015-10-01

    The relationship between the particulate matter in the atmosphere of Malaga and the origin of air masses with special attention to African intrusions was analyzed. The concentrations of PM10 and the activities of some radionuclides ((7)Be and (210)Pb) as tracers of these intrusions are discussed. The origin of these radiotracers is completely different. (210)Pb is a good tracer of air masses traveling close to the ground and come from inland areas. On the other hand, the production of (7)Be is very low in the vicinity of the Earth's surface, and increases with altitude, making it a great tracer of stratospheric air masses in the troposphere. Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of (7)Be and (210)Pb in aerosols at Malaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2009-2011 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory. The average concentration values of (7)Be and (210)Pb over the 3-year period have been found to be 5.05 and 0.55 mBq m(-3), respectively, with mean aerosol mass concentration of 53.6 μg m(-3). Taking into account the outbreaks of the daily values limits of PM10 in the study period (2009-2011), the origin of air masses is studied to explain three different situations of both radionuclides (7)Be and (210)Pb: 1) high concentrations of (7)Be and low concentrations of (210)Pb; 2) high concentrations of (210)Pb and low concentrations of (7)Be and 3) high concentrations of (7)Be and (210)Pb. PMID:26164283

  15. The western Mediterranean basin as an aged aerosols reservoir. Insights from an old-fashioned but efficient radiotracer

    NASA Astrophysics Data System (ADS)

    Brattich, E.; Hernández-Ceballos, M. A.; Orza, J. A. G.; Bolívar, J. P.; Tositti, L.

    2016-09-01

    The long-term contemporary 210Pb time series acquired during the period 2004-2011 at two distant sites of different altitude in the Mediterranean basin, El Arenosillo (40 m a.s.l. in southwestern Spain) and Mt. Cimone (2165 m a.s.l. in northern Italy), are analyzed and compared. Besides being considered a tracer of continental air masses, 210Pb radionuclide is also a proxy of fine stable aerosol. For this reason, the measurements of PM10 mass concentrations collected at the same time and the corresponding 210Pb/PM10 ratio at the two sites are considered to gain better insights into the origin and size of the particles. Three statistical trajectory methods are applied to identify and characterize the 210Pb source regions at the two sites. The three methods yield similar outcomes in the source identification, which strengthens the robustness of our results. In addition to the importance of the transport from areas of continental Europe, this study highlights the relevant role of the Mediterranean Sea as a major 210Pb reservoir layer associated to the aged air masses that accumulate in the western Mediterranean basin. The analysis of the sources points out the significant influence of northern Africa to 210Pb increases at both sites as well, even though the most intensive episodes are not of Saharan origin.

  16. In vitro evaluation of radioiodinated butyrophenones as radiotracer for dopamine receptor study

    SciTech Connect

    Nakatsuka, I.; Saji, H.; Shiba, K.; Shimizu, H.; Okuno, M.; Yoshitake, A.; Yokoyama, A.

    1987-10-26

    Radioiodinated butyrophenone compounds are attracting the interest of those working on dopamine receptor studies; structure-activity relationship study has revealed the ortho position of the p-fluorobutyrophenone moiety as a very plausible iodination site. Various synthesized butyrophenones iodinated at the ortho position of p-fluorobutyrophenone moiety, 2'-iodohaloperidol (2'-IHP), 2'-iodotrifluperidol (2'-ITP) and 2'-iodospiperone (2'-ISP) were tested for their abilities to inhibit /sup 3/H-spiperone (SP) binding for the dopamine (D-2) receptor, together with reference compounds (SP, haloperidol(HP) and 4-iodospiperone (4-ISP)). The order of binding affinity of the tested compounds was SP > 2'-ISP > HP > 4-ISP > 2'-IHP > 2'-ITP. Whereas, the serotonin (S-2) receptor binding affinity of SP and its iodinated analogues were in the order of SP >> 4-ISP > 2'-ISP. These data indicated the 2'-ISP as holding high affinity for dopamine receptors and a low affinity for serotonin receptors. Thus, the /sup 125/I-2'-ISP was a very potent radioligand for in vitro dopamine (D-2) receptor studies, and /sup 123/I-2'-ISP holds very promising characteristics as for in vivo dopamine receptor studies, as well.

  17. Radio-tracer techniques for the study of flow in saturated porous materials

    USGS Publications Warehouse

    Skibitzke, H.E.; Chapman, H.T.; Robinson, G.M.; McCullough, Richard A.

    1961-01-01

    An experiment was conducted by the U.S. Geological Survey to determine the feasibility of using a radioactive substance as a tracer in the study of microscopic flow in a saturated porous solid. A radioactive tracer was chosen in preference to dye or other chemical in order to eliminate effects of the tracer itself on the flow system such as those relating to density, viscosity and surface tension. The porous solid was artificial "sandstone" composed of uniform fine grains of sand bonded together with an epoxy adhesive. The sides of the block thus made were sealed with an epoxy coating compound to insure water-tightness. Because of the chemical inertness of the block it was possible to use radioactive phosphorus (P32). Ion-exchange equilibrium was created between the block and nonradioactive phosphoric acid. Then a tracer tagged with P32 was injected into the block in the desired geometric configuration, in this case, a line source. After equilibrium in isotopic exchange was reached between the block and the line source, the block was rinsed, drained and sawn into slices. It was found that a quantitative analysis of the flow system may be made by assaying the dissected block. ?? 1961.

  18. Model studies using supercritical carbon dioxide fluid (SF CO{sub 2}) as a reaction medium for radiotracer synthesis and purification

    SciTech Connect

    Ferrieri, R.A.; Fowler, J.S.; Wolf, A.P.

    1994-05-01

    Supercritical fluids (SFs) have found widespread use in the analytical field as solvents for compound purification, and initial results on their use for radiotracer synthesis have been reported. SF`s possess the unique feature that their solvating strength can be altered drastically through small changes in pressure and temperature of the fluid within the supercritical regime. We have modified a SF chromatograph to allow us to investigate its use in radiotracer synthesis and purification. The solubility of several PET radiotracers was measured in SF CO{sub 2} at 5000 psi and 55{degrees}C and showed the following: raclopride, 68 {mu}g/mL{sup 2}; (L)-deprenyl, 85 {mu}g/mL; flumazenil, 61 {mu}g/mL; (-)cocaine, 108 {mu}g/mL; ritalin, 45 {mu}g/Ml; and cogentin, 250 {mu}g/mL. Analytical separations were achieved on 30 to 50 {mu}g amounts of (L)-deprenyl (3.9 min RT) and nor-deprenyl (4.7 min RT), as well as raclopride (10.8 min RT) and nor-raclopride (10.3 min RT) using 250 mm x 4.5 mm i.d. Ultracarb 5 ODS (30), and 75 mm x 4.5 mm i.d. silica columns, respectively, and pure SF CO{sub 2} as the mobile phase. Model studies on simple N-alkylation reactions were also carried out using pur SF CO{sub 2} as the reaction medium on a modified alumina support. (L)-Deprenyl was synthesized from only 100 {mu}g of the starting labelling substrate using 500 mg of alumina impregnated with triphenylphosphine diiodide (20% by wt.) and maintained at 170{degrees}C. The methylating agent, methyl iodide, was generated in situ from methanol, but was always present in excess of the substrate. Studies are in progress to reduce methanol amounts. Pressure studies of SF CO{sub 2} ranging from 3000 to 6000 psi showed an 80% increase in the methylation reaction relative to the amount of starting substrate suggesting an effect of the fluid density. Temperature was also a critical parameter here as the reaction did not proceed at 80{degrees}C for similiar pressures.

  19. PET Radiotracers: crossing the blood-brain barrier and surviving metabolism

    PubMed Central

    Pike, Victor W.

    2009-01-01

    Radiotracers for imaging protein targets in living human brain with positron emission tomography (PET) are increasingly useful in clinical research and in drug development. Such radiotracers must fulfill many criteria, among which an ability to enter brain adequately and reversibly without contamination by troublesome radiometabolites is desirable for accurate measurement of the density of a target protein (e.g., neuroreceptor, transporter, enzyme or plaque). Candidate radiotracers may fail as a result of poor passive brain entry, rejection from brain by efflux transporters or undesirable metabolism. These issues are reviewed. Emerging PET radiotracers for measuring efflux transporter function, and new strategies for ameliorating radiotracer metabolism are discussed. A growing understanding of the molecular features affecting the brain penetration, metabolism and efflux transporter sensitivity of prospective radiotracers should ultimately lead to their more rational and efficient design, and also to their greater efficacy. PMID:19616318

  20. FLARE EFFICIENCY STUDY

    EPA Science Inventory

    The report gives results of a full-scale experimental study to determine the efficiencies of flare burners for disposing of hydrocarbon (HC) emissions from refinery and petrochemical processes. With primary objectives of determining the combustion efficiency and HC destruction ef...

  1. Vivid tumor imaging utilizing liposome-carried bimodal radiotracer.

    PubMed

    Kim, Jonghee; Pandya, Darpan N; Lee, Woonghee; Park, Jang Woo; Kim, Youn Ji; Kwak, Wonjung; Ha, Yeong Su; Chang, Yongmin; An, Gwang Il; Yoo, Jeongsoo

    2014-04-10

    By developing a new bimodal radioactive tracer that emits both luminescence and nuclear signals, a trimodal liposome for optical, nuclear, and magnetic resonance imaging is efficiently prepared. Fast clearance of the radiotracer from reticuloendothelial systems enables vivid tumor imaging with minimum background. PMID:24900846

  2. Bioconcentration of Ag, Cd, Co, Mn and Zn in the Mangrove Oyster (Crassostrea gasar) and Preliminary Human Health Risk Assessment: A Radiotracer Study.

    PubMed

    Kuranchie-Mensah, Harriet; Teyssié, Jean-Louis; Oberhänsli, François; Tumnoi, Yutthana; Pouil, Simon; Warnau, Michel; Metian, Marc

    2016-09-01

    Bioaccumulation kinetics of five dissolved metals were determined in the mangrove oyster Crassostrea gasar, using corresponding radiotracers ((54)Mn, (57)Co, (65)Zn, (109)Cd and (110m)Ag). Additionally, their bioaccessibility to human consumers was estimated. Results indicated that over a 14-day exposure (54)Mn and (57)Co were linearly concentrated in oysters whereas (109)Cd, (65)Zn and (110m)Ag were starting to saturate (steady-state not reached). Whole-body concentration factors at 14 days (CF14d in toto) ranged from 187 ± 65 to 629 ± 179 with the lowest bioconcentration capacity for Co and the highest for Ag. Depuration kinetics were best described by a double-exponential model with associated biological half-lives ranging from 26 days (Ag) to almost 8 months (Zn and Cd). Bioaccessible fraction of the studied elements was estimated using in vitro digestions, which suggested that oysters consumed seasoned with lemon enhanced the accessibility of Cd, Mn and Zn to human consumers, but not Ag and Co. PMID:27194421

  3. Radiotracers for PETT: new developments and perspectives

    SciTech Connect

    Fowler, J.S.; Wolf, A.P.

    1983-01-01

    Radiotracer development with positron emitters has its major focus on problems in the neurosciences. Progress is reviewed for high-level isotope production and labelled precurser synthesis with the medical cyclotron. The study of regional brain glucose metabolism represented the first extension of one of the methods of neurochemical autoradiography to humans and the study of brain protein synthesis and neurotransmitter receptors followed. In a more general sense, one PETT instrumentation will provide resolution in the 5 mm range is already emerging. Research status is reviewed. 103 references. (PSB)

  4. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    NASA Astrophysics Data System (ADS)

    Chughtai, I. R.; Iqbal, W.; Din, G. U.; Mehdi, S.; Khan, I. H.; Inayat, M. H.; Jin, J. H.

    2013-05-01

    A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD) analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl) scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM) was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe˜102) which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  5. The Expanding Reach of Environmental Radiotracers - New Chronometers And More Sensitive Measurements

    NASA Astrophysics Data System (ADS)

    Aalseth, C.

    2015-12-01

    Radiotracers in the environment provide powerful tools for understanding environmental processes. Viewed as an age continuum, methods using shorter-lived radionuclides (<100 y) like 3H, 7Be, 85Kr, 134Cs, and 137Cs generally rely on measurements of radioactive decay in samples. Methods using longer-lived radionuclides (>1,000 y) like 10Be, 14C, 36Cl, and 81Kr generally rely on atom-counting measurements such as accelerator mass spectrometry. Significant challenges exist in the age range between 100 and 1,000 years where useful radiotracers are difficult to measure by either method and can have very low abundance. These challenges are being addressed with more sensitive measurements using both atom counting and radioactive decay, extending the reach of established radiotracers as well as adding new chronometers. Improvements in atom-counting methods will be reviewed; the practicality of using 81Kr (abundance ~5×10-13 in atmospheric krypton) for age-dating old aquifers has been established and current work focuses on improving sample utilization efficiency to allow smaller samples to be measured. Better efficiency also brings lower-abundance isotopes within reach, for example 39Ar. Improvements in radioactive decay counting will be reviewed; these take advantage of ultra-pure materials to achieve lower backgrounds and are adding new age-dating reach to the environmental science tool-set with intermediate half-life radionuclides, for example 32Si for sediment cores. These methods also improve sensitivity for established radiotracers like 3H and will allow smaller samples to be measured, allowing specific processes to be traced. For example, using 3H as an indicator of carbon cycling through organic compounds in soil systems. Progress in both atom counting and decay counting is expanding the use of 39Ar for age-dating aquifers, measuring ocean mixing, and age-dating younger glacial ice. Argon-39 is a challenging intermediate-age radiotracer (269-year half-life) with

  6. The heritage of radiotracers for PET

    SciTech Connect

    Fowler, J.S.; Wolf, A.P.

    1988-05-01

    The history of PET research clearly demonstrates that it is advances in chemistry coupled with a detailed examination of the biochemistry of new radiotracers which has allowed the PET method to be applied to new areas of biology and medicine. Radiotracers whose regional distribution reflects glucose metabolism, neutrotransmitter activity and enzyme activity have all required the development of rapid synthetic methods for the radiotracers themselves and the characterization of their biochemical behavior. This article traces some of the advances in the production of labeled precursors and in radiotracer synthesis and evaluation which have shaped the rapidly expanding application of PET to problems in the neurosciences, in cardiology and in oncology. 54 refs.

  7. The Heritage of Radiotracers for PET

    DOE R&D Accomplishments Database

    Fowler, J. S.; Wolf, A. P.

    1988-05-01

    The history of PET research clearly demonstrates that it is advances in chemistry coupled with a detailed examination of the biochemistry of new radiotracers which has allowed the PET method to be applied to new areas of biology and medicine. Radiotracers whose regional distribution reflects glucose metabolism, neutrotransmitter activity and enzyme activity have all required the development of rapid synthetic methods for the radiotracers themselves and the characterization of their biochemical behavior. This article traces some of the advances in the production of labeled precursors and in radiotracer synthesis and evaluation which have shaped the rapidly expanding application of PET to problems in the neurosciences, in cardiology and in oncology.

  8. Principle component analysis for radiotracer signal separation.

    PubMed

    Kasban, H; Arafa, H; Elaraby, S M S

    2016-06-01

    Radiotracers can be used in several industrial applications by injecting the radiotracer into the industrial system and monitoring the radiation using radiation detectors for obtaining signals. These signals are analyzed to obtain indications about what is happening within the system or to determine the problems that may be present in the system. For multi-phase system analysis, more than one radiotracer is used and the result is a mixture of radiotracers signals. The problem is in such cases is how to separate these signals from each other. The paper presents a proposed method based on Principle Component Analysis (PCA) for separating mixed two radiotracer signals from each other. Two different radiotracers (Technetium-99m (Tc(99m)) and Barium-137m (Ba(137m))) were injected into a physical model for simulation of chemical reactor (PMSCR-MK2) for obtaining the radiotracer signals using radiation detectors and Data Acquisition System (DAS). The radiotracer signals are mixed and signal processing steps are performed include background correction and signal de-noising, then applying the signal separation algorithms. Three separation algorithms have been carried out; time domain based separation algorithm, Independent Component Analysis (ICA) based separation algorithm, and Principal Components Analysis (PCA) based separation algorithm. The results proved the superiority of the PCA based separation algorithm to the other based separation algorithm, and PCA based separation algorithm and the signal processing steps gives a considerable improvement of the separation process. PMID:26974488

  9. Design, synthesis and evaluation of [(3)H]PF-7191, a highly specific nociceptin opioid peptide (NOP) receptor radiotracer for in vivo receptor occupancy (RO) studies.

    PubMed

    Zhang, Lei; Drummond, Elena; Brodney, Michael A; Cianfrogna, Julie; Drozda, Susan E; Grimwood, Sarah; Vanase-Frawley, Michelle A; Villalobos, Anabella

    2014-11-15

    Herein we report the identification of (+)-N-(2-((1H-pyrazol-1-yl)methyl)-3-((1R,3r,5S)-6'-fluoro-8-azaspiro[bicyclo[3.2.1]octane-3,1'-isochroman]-8-yl)propyl)-N-[(3)H]-methylacetamide {[(3)H]PF-7191 [(+)-11]} as a promising radiotracer for the nociceptin opioid peptide (NOP) receptor. (+)-11 demonstrated high NOP binding affinity (Ki = 0.1 nM), excellent selectivity over other opioid receptors (>1000×) and good brain permeability in rats (C(b,u)/C(p,u) = 0.29). Subsequent characterization of [(3)H](+)-11 showed a high level of specific binding and a brain bio-distribution pattern consistent with known NOP receptor expression. Furthermore, the in vivo brain binding of [(3)H](+)-11 in rats was inhibited by a selective NOP receptor antagonist in a dose-responsive manner. This overall favorable profile indicated that [(3)H](+)-11 is a robust radiotracer for pre-clinical in vivo receptor occupancy (RO) measurements and a possible substrate for carbon-11 labeling for positron emission tomography (PET) imaging in higher species. PMID:25442316

  10. A Mn-54 Radiotracer Study of Mn Isotope Solid-Liquid Exchange during Reductive Transformation of Vernadite (δ-MnO₂) by Aqueous Mn(II)

    SciTech Connect

    Elzinga, Evert J.; Kustka, Adam B.

    2015-04-09

    We employed Mn-54 radiotracers to characterize the extent and dynamics of Mn atom exchange between aqueous Mn(II) and vernadite (δ-Mn(IV)O2) at pH 7.5 under anoxic conditions. Exchange of Mn atoms between the solid and liquid phase is rapid, reaching dynamic equilibrium in 2–4 days. We propose that during the initial stages of reaction, Mn atom exchange occurs through consecutive comproportionation-disproportionation reactions where interfacial electron transfer from adsorbed Mn(II) to lattice Mn(IV) generates labile Mn(III) cations that rapidly disproportionate to reform aqueous Mn(II) and solid-phase Mn(IV). Following nucleation of Mn(III)OOH phases, additional exchange likely occurs through electron transfer from aqueous Mn(II) to solid-phase Mn(III). Our results provide evidence for the fast and extensive production of transient Mn(III) species at the vernadite surface upon contact of this substrate with dissolved Mn(II). We further show that HEPES buffer is a reductant of lattice Mn(IV) in the vernadite structure in our experiments. The methods and results presented here introduce application of Mn-54 tracers as a facile tool to further investigate the formation kinetics of labile Mn(III) surface species and their impacts on Mn-oxide structure and reactivity over a range of environmentally relevant geochemical conditions.

  11. Radiotracer investigation in a glass production unit.

    PubMed

    Pant, H J; Goswami, Sunil; Biswal, Jayashree; Samantaray, J S; Sharma, V K; Singhal, Sorabh

    2016-10-01

    A radiotracer investigation was carried out in a glass production unit in a glass industry. Lanthanum-140 as lanthanium oxide mixed with silica was used as a radiotracer to trace the molten glass in various sections of the unit. Residence time distributions of molten glass were measured and analyzed to identify the flow abnormities. The flow parameters such as breakthrough time, mean residence time, homogenization time, dead volume and flow patterns in different sections of the unit were obtained from the measured RTD data. The results of the investigation were used to improve and optimize the operation of the glass production unit. PMID:27474905

  12. A method based on Monte Carlo simulations and voxelized anatomical atlases to evaluate and correct uncertainties on radiotracer accumulation quantitation in beta microprobe studies in the rat brain

    NASA Astrophysics Data System (ADS)

    Pain, F.; Dhenain, M.; Gurden, H.; Routier, A. L.; Lefebvre, F.; Mastrippolito, R.; Lanièce, P.

    2008-10-01

    The β-microprobe is a simple and versatile technique complementary to small animal positron emission tomography (PET). It relies on local measurements of the concentration of positron-labeled molecules. So far, it has been successfully used in anesthetized rats for pharmacokinetics experiments and for the study of brain energetic metabolism. However, the ability of the technique to provide accurate quantitative measurements using 18F, 11C and 15O tracers is likely to suffer from the contribution of 511 keV gamma rays background to the signal and from the contribution of positrons from brain loci surrounding the locus of interest. The aim of the present paper is to provide a method of evaluating several parameters, which are supposed to affect the quantification of recordings performed in vivo with this methodology. We have developed realistic voxelized phantoms of the rat whole body and brain, and used them as input geometries for Monte Carlo simulations of previous β-microprobe reports. In the context of realistic experiments (binding of 11C-Raclopride to D2 dopaminergic receptors in the striatum; local glucose metabolic rate measurement with 18F-FDG and H2O15 blood flow measurements in the somatosensory cortex), we have calculated the detection efficiencies and corresponding contribution of 511 keV gammas from peripheral organs accumulation. We confirmed that the 511 keV gammas background does not impair quantification. To evaluate the contribution of positrons from adjacent structures, we have developed β-Assistant, a program based on a rat brain voxelized atlas and matrices of local detection efficiencies calculated by Monte Carlo simulations for several probe geometries. This program was used to calculate the 'apparent sensitivity' of the probe for each brain structure included in the detection volume. For a given localization of a probe within the brain, this allows us to quantify the different sources of beta signal. Finally, since stereotaxic accuracy is

  13. Production of gaseous radiotracers for industrial applications.

    PubMed

    Sharma, V K; Pant, H J; Goswami, Sunil; Jagadeesan, K C; Anand, S; Chitra, S; Rana, Y S; Sharma, Archana; Singh, Tej; Gujar, H G; Dash, Ashutosh

    2016-10-01

    This paper describes prerequisite tests, analysis and the procedure for irradiation of gaseous targets and production of gaseous radioisotopes i.e. argon-41 ((41)Ar) and krypton-79 ((79)Kr) in a 100MWTh DHRUVA reactor located at Bhabha Atomic Research Center (BARC), Trombay, Mumbai, India. The produced radioisotopes will be used as radiotracers for tracing gas phase in industrial process systems. Various details and prequalification tests required for irradiation of gaseous targets are discussed. The procedure for regular production of (41)Ar and (79)Kr, and assay of their activity were standardized. Theoretically estimated and experimentally produced amounts of activities of the two radioisotopes, irradiated at identical conditions, were compared and found to be in good agreement. Based on the various tests, radiological safety analysis and standardization of the irradiation procedure, necessary approval was obtained from the competent reactor operating and safety authorities for regular production of gaseous radiotracers in DHRUVA reactor. PMID:27518216

  14. Molecular Imaging of Prostate Cancer: PET Radiotracers

    PubMed Central

    Jadvar, Hossein

    2012-01-01

    OBJECTIVE Recent advances in the fundamental understanding of the complex biology of prostate cancer have provided an increasing number of potential targets for imaging and treatment. The imaging evaluation of prostate cancer needs to be tailored to the various phases of this remarkably heterogeneous disease. CONCLUSION In this article, I review the current state of affairs on a range of PET radiotracers for potential use in the imaging evaluation of men with prostate cancer. PMID:22826388

  15. Bioaccumulation of (63)Ni in the scleractinian coral Stylophora pistillata and isolated Symbiodinium using radiotracer techniques.

    PubMed

    Hédouin, Laetitia; Metian, Marc; Teyssié, Jean-Louis; Oberhänsli, François; Ferrier-Pagès, Christine; Warnau, Michel

    2016-08-01

    Development of nickel mining activities along the New Caledonia coasts threatens the biodiversity of coral reefs. Although the validation of tropical marine organisms as bioindicators of metal mining contamination has received much attention in the literature over the last decade, few studies have examined the potential of corals, the fundamental organisms of coral reefs, to monitor nickel (Ni) contamination in tropical marine ecosystems. In an effort to bridge this gap, the present work investigated the bioaccumulation of (63)Ni in the scleractinian coral Stylophora pistillata and in its isolated zooxanthellae Symbiodinium, using radiotracer techniques. Results highlight the high capacities of coral tissues (zooxanthellae and host tissues) to efficiently bioconcentrate (63)Ni compared to skeleton (Concentration Factors CF at 14 days of exposure are 3 orders of magnitude higher in tissues than in skeleton). When non-contaminated conditions were restored, (63)Ni was more efficiently retained in skeleton than in coral tissues, with biological half-lives (Tb½) of 44.3 and 6.5 days, respectively. In addition, our work showed that Symbiodinium bioconcentrated (63)Ni exponentially, with a vol/vol concentration factor at steady state (VCFSS) reaching 14,056. However, compilation of our results highlighted that despite efficient bioconcentration of (63)Ni in Symbiodinium, their contribution to the whole (63)Ni accumulation in coral nubbins represents less than 7%, suggesting that other biologically controlled processes occur in coral host allowing such efficient bioconcentration in coral tissues. PMID:27192479

  16. Impact of expression system on the function of the C6.5 diabody PET radiotracer.

    PubMed

    Miller, Joshua; Doss, Mohan; McQuillen, Ryan; Shaller, Calvin C; Tolner, Berend; Yu, Jian Q; Chester, Kerry; Robinson, Matthew K

    2012-06-01

    The ability of engineered antibodies to rapidly and selectively target tumors that express their target antigen makes them well suited for use as radioimaging tracers. The combination of molecular size and bivalent nature makes diabody molecules a particularly promising structure for use as radiotracers for diagnostic imaging. Previous data have demonstrated that the anti-HER2 C6.5 diabody (C6.5db) is an effective radiotracer in preclinical models of HER2-positive cancer. The aim of this study was to evaluate the impact on radiotracer performance, associated with expressing the C6.5db in the Pichia pastoris (P-C6.5db) system as compared to Escherichia coli (E. C6.5db). Glycosylation of P-C6.5db led to faster blood clearance and lower overall tumor uptake than seen with E. coli-produced C6.5db. However, P-C6.5db achieved high tumor/background ratios that are critical for effective imaging. Dosimetry measurements determined in this study for both (124)I-P-C6.5db and (124)I-E-C6.5db suggest that they are equivalent to other radiotracers currently being administered to patients. PMID:22383295

  17. Radiotracer Imaging of Sediment Columns

    NASA Astrophysics Data System (ADS)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (<1 day). This allows multiple measurements to be made on the same column and thus the sediment biology to be monitored non-invasively over time (i.e. after an augmentation has been introduced) and minimizes long-lived radioactive waste. Different parameters can be measured, depending on the tracer type and delivery. A constant infusion of a conservative tracer, such as the positron emitter Br-76 (T1/2= 16.2 hr), measures the exclusion fraction (as

  18. Methods to Increase the Metabolic Stability of (18)F-Radiotracers.

    PubMed

    Kuchar, Manuela; Mamat, Constantin

    2015-01-01

    The majority of pharmaceuticals and other organic compounds incorporating radiotracers that are considered foreign to the body undergo metabolic changes in vivo. Metabolic degradation of these drugs is commonly caused by a system of enzymes of low substrate specificity requirement, which is present mainly in the liver, but drug metabolism may also take place in the kidneys or other organs. Thus, radiotracers and all other pharmaceuticals are faced with enormous challenges to maintain their stability in vivo highlighting the importance of their structure. Often in practice, such biologically active molecules exhibit these properties in vitro, but fail during in vivo studies due to obtaining an increased metabolism within minutes. Many pharmacologically and biologically interesting compounds never see application due to their lack of stability. One of the most important issues of radiotracers development based on fluorine-18 is the stability in vitro and in vivo. Sometimes, the metabolism of (18)F-radiotracers goes along with the cleavage of the C-F bond and with the rejection of [(18)F]fluoride mostly combined with high background and accumulation in the skeleton. This review deals with the impact of radiodefluorination and with approaches to stabilize the C-F bond to avoid the cleavage between fluorine and carbon. PMID:26404227

  19. Synthesis of radiotracers for studying muscarinic cholinergic receptors in the living human brain using positron emission tomography: [11C]dexetimide and [11C]levetimide.

    PubMed

    Dannals, R F; Långström, B; Ravert, H T; Wilson, A A; Wagner, H N

    1988-01-01

    Dexetimide (Fig. 1a), a potent muscarinic cholinergic receptor antagonist, and levetimide (Fig. 1b), its pharmacologically inactive enantiomer, were labeled with 11C for non-invasive in vivo studies of muscarinic cholinergic receptors in the human brain using positron emission tomography. The syntheses were completed in approximately 32 min using [alpha-11C]benzyl iodide as the precursor. The synthesis, purification, characterization and determination of specific activity are presented and discussed. PMID:2838435

  20. Diffusion Experiment in Lithium Ionic Conductors with the Radiotracer of {sup 8}Li: from Micro- to Nano-diffusion

    SciTech Connect

    Jeong, Sun-Chan; Katayama, Ichiro; Kawakami, Hirokane; Watanabe, Yutaka; Ishiyama, Hironobu; Imai, Nobuaki; Hirayama, Yoshikazu; Miyatake, Hiroari; Sataka, Masao; Sugai, Hiroyuki; Okayasu, Satoru; Ichikawa, Shin-Ichi; Nishio, Katsuhisa; Mitsuoka, Shinichi; Nakanoya, Takamitsu; Hashimoto, Takashi; Hashimoto, Takanori; Yahagi, Masahito

    2009-05-04

    We have developed a radiotracer method for diffusion studies in lithium ionic conductors, by using, as the tracer, the short-lived {alpha}-emitting radioisotope of {sup 8}Li from TRIAC (Tokai Radioactive Ion Accelerator Complex). In the method, we measured {alpha}-particles coming out of the sample of interest and have found that the time-dependent yields of {alpha}-particle from the diffusing {sup 8}Li primarily implanted is a good measure of the Li diffusion in the sample. The method has been successfully applied to measure the lithium diffusion coefficients in a typical defect-mediated lithium ionic conductor of LiGa, well demonstrating that the method is very efficient to measure the diffusion in the micro-meter regime per second. Further development, as an extension of the present method, was proposed to measure the diffusion on the nanoscale in lithium ionic conductors.

  1. High efficiency thermionic converter studies

    NASA Technical Reports Server (NTRS)

    Huffman, F. N.; Sommer, A. H.; Balestra, C. L.; Briere, T. R.; Lieb, D.; Oettinger, P. E.; Goodale, D. B.

    1977-01-01

    Research in thermionic energy conversion technology is reported. The objectives were to produce converters suitable for use in out of core space reactors, radioisotope generators, and solar satellites. The development of emitter electrodes that operate at low cesium pressure, stable low work function collector electrodes, and more efficient means of space charge neutralization were investigated to improve thermionic converter performance. Potential improvements in collector properties were noted with evaporated thin film barium oxide coatings. Experiments with cesium carbonate suggest this substance may provide optimum combinations of cesium and oxygen for thermionic conversion.

  2. Long-Circulating and pH-Sensitive Liposome Preparation Trapping a Radiotracer for Inflammation Site Detection.

    PubMed

    Mota, Luciene Das Graças; de Barros, André Luís Branco; Fuscaldi, Leonardo Lima; de Oliveira, Mônica Cristina; Cardoso, Valbert Nascimento

    2015-06-01

    Inflammatory and infectious diseases are one of the most common causes of mortality and morbidity. This paper aimed to prepare and to evaluate the ability of long-circulating and pH-sensitive liposomes, trapping a radiotracer, to identify inflamed focus. The physicochemical characterization of freeze-dried liposomes, using glucose as cryoprotectant, showed 80% of the vesicles with adequate mean diameter and good vesicle size homogeneity. Radiotracer encapsulation percentage in liposomes was 10.65%, of which 4.88% was adsorbed on the surface of the vesicles. Furthermore, liposomes presented positive zeta potential. Freeze-dried liposomes, stored for 180 days at 4 degrees C, did not show significant changes in the mean diameter, indicating good stability. Free radiotracer and radiolabeled liposomes were injected into inflammation focus-bearing rats, and ex-vivo biodistribution studies and scintigraphic images were performed. Results showed that radiopharmaceutical, free and encapsulated into liposomes, were able to identify the inflamed site. Target/non-target ratios, obtained by scintigraphic images, were greater than 1.5 at all investigated times. Data did not show significant differences between the free radiotracer and radiolabeled liposomes. Results suggest that this liposomal preparation could be employed as an alternative procedure for inflamed site detection by means of scintigraphic images. However, as the radiotracer is adsorbed onto the liposome surface by electrostatic forces, it is suggested that a neutral radiopharmaceutical be used to confirm the potential of this formulation as a scintigraphic probe for inflammation/infection detection. PMID:26369024

  3. Radiotracer Technology in Mixing Processes for Industrial Applications

    PubMed Central

    Othman, N.; Kamarudin, S. K.

    2014-01-01

    Many problems associated with the mixing process remain unsolved and result in poor mixing performance. The residence time distribution (RTD) and the mixing time are the most important parameters that determine the homogenisation that is achieved in the mixing vessel and are discussed in detail in this paper. In addition, this paper reviews the current problems associated with conventional tracers, mathematical models, and computational fluid dynamics simulations involved in radiotracer experiments and hybrid of radiotracer. PMID:24616642

  4. Aqueous and dietary copper uptake and elimination in Daphnia magna determined by the ⁶⁷cu radiotracer.

    PubMed

    Zhao, Chun-Mei; Fan, Wen-Hong; Wang, Wen-Xiong

    2009-11-01

    Among the many toxic metals, the biokinetics of copper (Cu) in the freshwater cladoceran Daphnia magna have not been studied due to the lack of an ideal radiotracer. In the present study, a gamma radiotracer, ⁶⁷Cu (half-life = 61.9 h), was used to study the uptake of copper from the dissolved and dietary phase and efflux in D. magna, an important toxicity testing species. The influx rate of Cu from the dissolved phase increased with dissolved Cu concentration, with a calculated uptake rate constant of 0.055 L/g/h. The assimilation efficiency (AE) of Cu decreased significantly (from 92 to 16%) as the available food concentration increased, and the AE differed among the food types. As low as 1% of Cu AE was found in daphnids fed high concentrations (1.54 mg/L) of the green algae Chlorella pyrenoidosa. The AE decreased linearly as the ingestion rate of the daphnids increased. The efflux rate constant was 0.20/d at high food concentrations. Excretion accounted for 82 to 94% of total Cu loss from the animals, although Cu also was transferred maternally from female adults to their offspring. Under conditions of high food concentrations, approximately 6.5% of the mother's Cu was transferred to the offspring over 7 d. It was concluded that Cu accumulation is dominated by uptake from dietary sources, and there is a substantial need to understand the dietary toxicity of Cu to daphnids. The present study has implications for the choice of food particles in conducting the Cu toxicity testing in cladocerans. PMID:19839654

  5. Exploring the transport of plant metabolites using positron emitting radiotracers

    PubMed Central

    Kiser, Matthew R.; Reid, Chantal D.; Crowell, Alexander S.; Phillips, Richard P.; Howell, Calvin R.

    2008-01-01

    Short-lived positron-emitting radiotracer techniques provide time-dependent data that are critical for developing models of metabolite transport and resource distribution in plants and their microenvironments. Until recently these techniques were applied to measure radiotracer accumulation in coarse regions along transport pathways. The recent application of positron emission tomography (PET) techniques to plant research allows for detailed quantification of real-time metabolite dynamics on previously unexplored spatial scales. PET provides dynamic information with millimeter-scale resolution on labeled carbon, nitrogen, and water transport over a small plant-size field of view. Because details at the millimeter scale may not be required for all regions of interest, hybrid detection systems that combine high-resolution imaging with other radiotracer counting technologies offer the versatility needed to pursue wide-ranging plant physiological and ecological research. In this perspective we describe a recently developed hybrid detection system at Duke University that provides researchers with the flexibility required to carry out measurements of the dynamic responses of whole plants to environmental change using short-lived radiotracers. Following a brief historical development of radiotracer applications to plant research, the role of radiotracers is presented in the context of various applications at the leaf to the whole-plant level that integrates cellular and subcellular signals and∕or controls. PMID:19404430

  6. Development of a Fluorinated Class-I HDAC Radiotracer Reveals Key Chemical Determinants of Brain Penetrance.

    PubMed

    Strebl, Martin G; Wang, Changning; Schroeder, Frederick A; Placzek, Michael S; Wey, Hsiao-Ying; Van de Bittner, Genevieve C; Neelamegam, Ramesh; Hooker, Jacob M

    2016-05-18

    Despite major efforts, our knowledge about many brain diseases remains remarkably limited. Epigenetic dysregulation has been one of the few leads toward identifying the causes and potential treatments of psychiatric disease over the past decade. A new positron emission tomography radiotracer, [(11)C]Martinostat, has enabled the study of histone deacetylase in living human subjects. A unique property of [(11)C]Martinostat is its profound brain penetrance, a feature that is challenging to engineer intentionally. In order to understand determining factors for the high brain-uptake of Martinostat, a series of compounds was evaluated in rodents and nonhuman primates. The study revealed the major structural contributors to brain uptake, as well as a more clinically relevant fluorinated HDAC radiotracer with comparable behavior to Martinostat, yet longer half-life. PMID:26675505

  7. Sodium-22-radiolabeled silica nanoparticles as new radiotracer for biomedical applications: in vivo positron emission tomography imaging, biodistribution, and biocompatibility

    PubMed Central

    Al Faraj, Achraf; Alotaibi, Basem; Shaik, Abjal Pasha; Shamma, Khaled Z; Al Jammaz, Ibrahim; Gerl, Jürgen

    2015-01-01

    Despite their advantageous chemical properties for nuclear imaging, radioactive sodium-22 (22Na) tracers have been excluded for biomedical applications because of their extremely long lifetime. In the current study, we proposed, for the first time, the use of 22Na radiotracers for pre-clinical applications by efficiently loading with silica nanoparticles (SiNPs) and thus offering a new life for this radiotracer. Crown-ether-conjugated SiNPs (300 nm; −0.18±0.1 mV) were successfully loaded with 22Na with a loading efficacy of 98.1%±1.4%. Noninvasive positron emission tomography imaging revealed a transient accumulation of 22Na-loaded SiNPs in the liver and to a lower extent in the spleen, kidneys, and lung. However, the signal gradually decreased in a time-dependent manner to become not detectable starting from 2 weeks postinjection. These observations were confirmed ex vivo by quantifying 22Na radioactivity using γ-counter and silicon content using inductively coupled plasma-mass spectrometry in the blood and the different organs of interest. Quantification of Si content in the urine and feces revealed that SiNPs accumulated in the organs were cleared from the body within a period of 2 weeks and completely in 1 month. Biocompatibility evaluations performed during the 1-month follow-up study to assess the possibility of synthesized nanocarriers to induce oxidative stress or DNA damage confirmed their safety for pre-clinical applications. 22Na-loaded nanocarriers can thus provide an innovative diagnostic agent allowing ultra-sensitive positron emission tomography imaging. On the other hand, with its long lifetime, onsite generators or cyclotrons will not be required as 22Na can be easily stored in the nuclear medicine department and be used on-demand. PMID:26504381

  8. High efficiency thermionic converter studies

    NASA Technical Reports Server (NTRS)

    Huffman, F. N.; Sommer, A. H.; Balestra, C. L.; Briere, D. P.; Oettinger, P. E.

    1976-01-01

    The objective is to improve thermionic converter performance by means of reduced interelectrode losses, greater emitter capabilities, and lower collector work functions until the converter performance level is suitable for out-of-core space reactors and radioisotope generators. Electrode screening experiments have identified several promising collector materials. Back emission work function measurements of a ZnO collector in a thermionic diode have given values less than 1.3 eV. Diode tests were conducted over the range of temperatures of interest for space power applications. Enhanced mode converter experiments have included triodes operated in both the surface ionization and plasmatron modes. Pulsed triodes were studied as a function of pulse length, pulse potential, inert gas fill pressure, cesium pressure, spacing, emitter temperature and collector temperature. Current amplifications (i.e., mean output current/mean grid current) of several hundred were observed up to output current densities of one amp/sq cm. These data correspond to an equivalent arc drop less than 0.1 eV.

  9. SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for β-cell mass assessments

    PubMed Central

    Eter, Wael A.; Parween, Saba; Joosten, Lieke; Frielink, Cathelijne; Eriksson, Maria; Brom, Maarten; Ahlgren, Ulf; Gotthardt, Martin

    2016-01-01

    Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in β-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total β-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate β-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of β-cells. Uptake of a promising radiotracer for β-cell imaging by SPECT, 111In-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of 111In-exendin-3 and insulin positive β-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of β-cell radiotracers. PMID:27080529

  10. SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for β-cell mass assessments.

    PubMed

    Eter, Wael A; Parween, Saba; Joosten, Lieke; Frielink, Cathelijne; Eriksson, Maria; Brom, Maarten; Ahlgren, Ulf; Gotthardt, Martin

    2016-01-01

    Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in β-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total β-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate β-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of β-cells. Uptake of a promising radiotracer for β-cell imaging by SPECT, (111)In-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of (111)In-exendin-3 and insulin positive β-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of β-cell radiotracers. PMID:27080529

  11. Efficiency Studies in the British Universities.

    ERIC Educational Resources Information Center

    Lockwood, Geoffrey

    1986-01-01

    The background, purposes, and methods of institutional efficiency studies conducted at selected British universities are discussed. The evaluations focused on financial management, purchasing, and building maintenance and space utilization. (MSE)

  12. Diffusion of radiotracers in normal and ischemic brain slices.

    PubMed

    Patlak, C S; Hospod, F E; Trowbridge, S D; Newman, G C

    1998-07-01

    Diffusion in the extracellular space (ECS) is important in physiologic and pathologic brain processes but remains poorly understood. To learn more about factors influencing tissue diffusion and the role of diffusion in solute-tissue interactions, particularly during cerebral ischemia, we have studied the kinetics of several radiotracers in control and hypoxic 450-microm hippocampal slices and in 1,050-microm thick slices that model the ischemic penumbra. Kinetics were analyzed by nonlinear least squares methods using models that combine extracellular diffusion with tissue compartments in series or in parallel. Studies with 14C-polyethylene glycol confirmed prior measurements of extracellular volume and that ECS shrinks during ischemia. Separating diffusion from transport also revealed large amounts of 45Ca that bind to or enter brain as well as demonstrating a small, irreversibly bound compartment during ischemia. The rapidity of 3H2O entry into cells made it impossible for us to distinguish intracellular from extracellular diffusion. The diffusion-compartment analysis of 3-O-methylglucose data appears to indicate that 5 mmol/L glucose is inadequate to support glycolysis fully in thick slices. Unexpectedly, the diffusion coefficient for all four tracers rose in thick slices compared with thin slices, suggesting that ECS becomes less tortuous in the penumbra. PMID:9663508

  13. Radiotracers Used for the Scintigraphic Detection of Infection and Inflammation

    PubMed Central

    Tsopelas, Chris

    2015-01-01

    Over the last forty years, a small group of commercial radiopharmaceuticals have found their way into routine medical use, for the diagnostic imaging of patients with infection or inflammation. These molecular radiotracers usually participate in the immune response to an antigen, by tagging leukocytes or other molecules/cells that are endogenous to the process. Currently there is an advancing effort by researchers in the preclinical domain to design and develop new agents for this application. This review discusses radiopharmaceuticals used in the nuclear medicine clinic today, as well as those potential radiotracers that exploit an organism's defence mechanisms to an infectious or inflammatory event. PMID:25741532

  14. The uses of radiotracers in the life sciences

    NASA Astrophysics Data System (ADS)

    Ruth, Thomas J.

    2009-01-01

    Radionuclides have been used to follow physical, chemical and biological processes almost from the time of their discovery. Probably the application with the biggest impact has been in the medical field where radionuclides have been incorporated into biologically active molecules and used to diagnose a wide variety of diseases and to treat many disorders. Other uses in the life sciences, in general, are related to using a radioactive isotope as marker for an existing species such as nitrogen-13 in plant studies or copper-67 to track copper catalysts in phytoplankton. This review describes in general terms these uses as well as providing the reader with the background related to the physical properties of radioactive decay, the concepts associated with the production of radionuclides using reactors or accelerators and the fundamentals of imaging radioactivity. The advances in imaging technology in recent years has had a profound impact on the use of radionuclides in positron emission tomography and the coupling of other imaging modalities to provide very precise insights into human disease. The variety of uses for radiotracers in science is almost boundless dependent only upon ones imagination.

  15. Radiolabeled Cyclic RGD Peptides as Radiotracers for Imaging Tumors and Thrombosis by SPECT.

    PubMed

    Zhou, Yang; Chakraborty, Sudipta; Liu, Shuang

    2011-01-01

    The integrin family is a group of transmembrane glycoprotein comprised of 19 α- and 8 β-subunits that are expressed in 25 different α/β heterodimeric combinations on the cell surface. Integrins play critical roles in many physiological processes, including cell attachment, proliferation, bone remodeling, and wound healing. Integrins also contribute to pathological events such as thrombosis, atherosclerosis, tumor invasion, angiogenesis and metastasis, infection by pathogenic microorganisms, and immune dysfunction. Among 25 members of the integrin family, the α(v)β(3) is studied most extensively for its role of tumor growth, progression and angiogenesis. In contrast, the α(IIb)β(3 )is expressed exclusively on platelets, facilitates the intercellular bidirectional signaling ("inside-out" and "outside-in") and allows the aggregation of platelets during vascular injury. The α(IIb)β(3) plays an important role in thrombosis by its activation and binding to fibrinogen especially in arterial thrombosis due to the high blood flow rate. In the resting state, the α(IIb)β(3) on platelets does not bind to fibrinogen; on activation, the conformation of platelet is altered and the binding sites of α(IIb)β(3 )are exposed for fibrinogen to crosslink platelets. Over the last two decades, integrins have been proposed as the molecular targets for diagnosis and therapy of cancer, thrombosis and other diseases. Several excellent review articles have appeared recently to cover a broad range of topics related to the integrin-targeted radiotracers and their nuclear medicine applications in tumor imaging by single photon emission computed tomography (SPECT) or a positron-emitting radionuclide for positron emission tomography (PET). This review will focus on recent developments of α(v)β(3)-targeted radiotracers for imaging tumors and the use of α(IIb)β(3)-targeted radiotracers for thrombosis imaging, and discuss different approaches to maximize the targeting capability of

  16. Ultra-efficient Engine Diameter Study

    NASA Technical Reports Server (NTRS)

    Daggett, David L.; Brown, Stephen T.; Kawai, Ron T.

    2003-01-01

    Engine fan diameter and Bypass Ratio (BPR) optimization studies have been conducted since the beginning of the turbofan age with the recognition that reducing the engine core jet velocity and increasing fan mass flow rate generally increases propulsive efficiency. However, performance tradeoffs limit the amount of fan flow achievable without reducing airplane efficiency. This study identifies the optimum engine fan diameter and BPR, given the advanced Ultra-Efficient Engine Technology (UEET) powerplant efficiencies, for use on an advanced subsonic airframe. Engine diameter studies have historically focused on specific engine size options, and were limited by existing technology and transportation infrastructure (e.g., ability to fit bare engines through aircraft doors and into cargo holds). This study is unique in defining the optimum fan diameter and drivers for future 2015 (UEET) powerplants while not limiting engine fan diameter by external constraints. This report follows on to a study identifying the system integration issues of UEET engines. This Engine Diameter study was managed by Boeing Phantom Works, Seattle, Washington through the NASA Glenn Revolutionary Aero Space Engine Research (RASER) contract under task order 10. Boeing Phantom Works, Huntington Beach, completed the engine/airplane sizing optimization, while the Boeing Commercial Airplane group (BCA) provided design oversight. A separate subcontract to support the overall project was issued to Tuskegee University.

  17. Methods for studying close-track efficiency

    SciTech Connect

    Mac Mestayer; Konstantin Mikhaylov; Aleksey Stavinskiy; Alexander Vlassov

    2004-05-01

    Wire chambers used for particle tracking suffer a loss of efficiency when the trajectories of two particles from the same event are very close together in space. We describe two new methods for the study of this close-track efficiency. One is based on the study of a correlation function for particles with different masses as a function of their relative momenta in the laboratory reference system. The other method is based on the analysis of artificial events, constructed by merging raw data from separate events. Both methods and the standard Monte Carlo method were applied to data from the CLAS detector at Jefferson Laboratory. All three methods provide the same result for close-track efficiency with an accuracy sufficient for practical application.

  18. Stress and efficiency studies in EFG

    NASA Technical Reports Server (NTRS)

    Kalejs, J. P.

    1984-01-01

    Stress and efficiency studies in EFG were carried out for silicon sheet growth. Methods were developed to quantify influence of dislocation electrical activity on bulk lifetime. A new creep law formulation for silicon stress was developed. Bulk lifetime degradation due to increase in doping levels was also examined.

  19. The Study on Energy Efficiency in Africa

    NASA Astrophysics Data System (ADS)

    Wu, Jinduo

    This paper is dedicated to explore the dynamic performance of energy efficiency in Africa, with panel data in country level, taking energy yield, power consumption, electricity transmission and distribution losses into account, the paper employ stochastic frontier mode,highlighting a dummy variable in energy output in terms of net imports of energy and power, which minify the deviation of estimated variables. The results show that returns of scale did not appear in energy and power industry in Africa, electricity transmission and distribution losses contribute most to GDP per unit of energy. In country level, Republic of Congo and Botswana suggest an obvious energy efficiency advantage. Energy efficiency in Mozambique and Democratic Republic of Congo are not very satisfying during the studying year

  20. [18F]Fluoromethyl-[1,2-2H4]-choline: A novel radiotracer for imaging choline metabolism in tumors by positron emission tomography

    PubMed Central

    Leyton, Julius; Smith, Graham; Zhao, Yongjun; Perumal, Meg; Nguyen, Quang-De; Robins, Edward; Årstad, Erik; Aboagye, Eric O.

    2009-01-01

    Current radiotracers for positron emission tomography (PET) imaging of choline metabolism have poor systemic metabolic stability in vivo. We describe a novel radiotracer, [18F]fluoromethyl-[1,2-2H4]-choline (D4-FCH), that employs deuterium isotope effect to improve metabolic stability. D4-FCH proved more resistant to oxidation than its non-deuterated analog, [18F]fluoromethylcholine (FCH), in plasma, kidneys, liver and tumor, while retaining phosphorylation potential. Tumor radiotracer levels, a determinant of sensitivity in imaging studies, was improved by deuterium substitution; tumor uptake values expressed as %injected dose/voxel at 60 min were 7.43 ± 0.47 and 5.50 ± 0.49 for D4-FCH and FCH, respectively, (P = 0.04). D4-FCH was also found to be a useful response biomarker. Treatment with the mitogenic extracellular kinase inhibitor, PD0325901, resulted in a reduction in tumor radiotracer uptake that occurred in parallel with reductions in choline kinase A expression. In conclusion, D4-FCH is a very promising metabolically stable radiotracer for imaging choline metabolism in tumors. PMID:19773436

  1. Optical reaction cell and light source for [18F] fluoride radiotracer synthesis

    DOEpatents

    Ferrieri, R.A.; Schlyer, D.; Becker, R.J.

    1998-09-15

    An apparatus is disclosed for performing organic synthetic reactions, particularly no-carrier-added nucleophilic radiofluorination reactions for PET radiotracer production. The apparatus includes an optical reaction cell and a source of broadband infrared radiant energy, which permits direct coupling of the emitted radiant energy with the reaction medium to heat the reaction medium. Preferably, the apparatus includes means for focusing the emitted radiant energy into the reaction cell, and the reaction cell itself is preferably configured to reflect transmitted radiant energy back into the reaction medium to further improve the efficiency of the apparatus. The apparatus is well suited to the production of high-yield syntheses of 2-[{sup 18}F]fluoro-2-deoxy-Dglucose. Also provided is a method for performing organic synthetic reactions, including the manufacture of [{sup 18}F]-labeled compounds useful as PET radiotracers, and particularly for the preparation of 2-[{sup 18}F]fluoro-2-deoxy-D-glucose in higher yields than previously possible. 4 figs.

  2. Optical reaction cell and light source for ›18F! fluoride radiotracer synthesis

    DOEpatents

    Ferrieri, Richard A.; Schlyer, David; Becker, Richard J.

    1998-09-15

    Apparatus for performing organic synthetic reactions, particularly no-carrier-added nucleophilic radiofluorination reactions for PET radiotracer production. The apparatus includes an optical reaction cell and a source of broadband infrared radiant energy, which permits direct coupling of the emitted radiant energy with the reaction medium to heat the reaction medium. Preferably, the apparatus includes means for focusing the emitted radiant energy into the reaction cell, and the reaction cell itself is preferably configured to reflect transmitted radiant energy back into the reaction medium to further improve the efficiency of the apparatus. The apparatus is well suited to the production of high-yield syntheses of 2-›.sup.18 F!fluoro-2-deoxy-D-glucose. Also provided is a method for performing organic synthetic reactions, including the manufacture of ›.sup.18 F!-labeled compounds useful as PET radiotracers, and particularly for the preparation of 2-›.sup.18 F!fluoro-2-deoxy-D-glucose in higher yields than previously possible.

  3. Prediction of water vapor transport rates across polyvinylchloride packaging systems using a novel radiotracer method

    SciTech Connect

    Wood, R.W.; Mulski, M.J.; Kuu, W.Y. )

    1990-09-01

    A radiotracer method is used to study the transport properties of water vapor in polyvinylchloride (PVC), a plastic commonly used in the packaging of parenteral solutions. Water vapor transport across a PVC film appears to be Fickian in nature. Using the steady-state solution of Fick's second law and the permeability coefficient of water vapor across the PVC film obtained using the described method, the predicted water vapor transport rate (WVTR) for a parenteral solution packaged in PVC is in reasonable agreement with actual WVTR as determined by weight loss under precisely controlled conditions.

  4. Energy-efficient electric motors study

    NASA Astrophysics Data System (ADS)

    1981-03-01

    A survey conducted of purchasers of integral horsepower polyphase motors measured current knowledge of and awareness of energy efficient motors, decision making criteria, information sources, purchase and usage patterns, and related factors. The data obtained were used for the electric motor market penetration analysis. Additionally, a telephone survey was made. The study also provides analyses of distribution channels, commercialization constraints, and the impacts of government programs and rising energy prices. Study findings, conclusions, and recommendations are presented. Sample questionnaires and copies of letters to respondents are presented in appendices as well as descriptions of the methods used.

  5. Microbially mediated cobalt oxidation in seawater revealed by radiotracer experiments

    SciTech Connect

    Lee, B.G.; Fisher, N.S. )

    1993-12-01

    The influence of microbial activity on Co and Mn oxidation in decomposing diatom cultures was determined with radiotracer techniques. Adding a consortium of microorganisms collected from coastal seawater (0.2-3-[mu]m size fraction) to the cultures increased particulate Co formation rates at 18[degrees]C by an order of magnitude (to 3.8% d[sup [minus]1]) and particulate Mn formation rates 3-fold (to 7.9% d[sup [minus

  6. OEPSS operationally efficient propulsion system study

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A final report on the Operationally Efficient Propulsion System Study (OEPSS) is presented. A review of Launch Site Operations, OEPSS objectives, operations support structure, OEPSS Concerns List, and scope of OEPSS are summarized, along with goals of OEPSS technologies, and operations technology levels. Air-augmented ejector/rocket, flash boiling tank pressurization technology, and advanced LH2 turbopump are described. Launch facilities, operations-driven propulsion system architecture, integrated booster propulsion module, turbopump operating conditions, and payload capability using integrated engine elements are addressed among other topics.

  7. Chemistry and biology of radiotracers that target changes in sympathetic and parasympathetic nervous systems in heart disease.

    PubMed

    Eckelman, William C; Dilsizian, Vasken

    2015-06-01

    Following the discovery of the sympathetic and parasympathetic nervous system, numerous adrenoceptor drugs were radiolabeled and potent radioligands were prepared in order to image the β-adrenergic and the muscarinic systems. But the greatest effort has been in preparing noradrenaline analogs, such as norepinephrine, (11)C-metahydroxyephedrine, and (123)I-metaiodobenzylguanidine that measure cardiac sympathetic nerve varicosities. Given the technical and clinical challenges in designing and validating targeted adrenoceptor-binding radiotracers, namely the heavily weighted flow dependence and relatively low target-to-background ratio, both requiring complicated mathematic analysis, and the inability of targeted adrenoceptor radioligands to have an impact on clinical care of heart disease, the emphasis has been on radioligands monitoring the norepinephrine pathway. The chemistry and biology of such radiotracers, and the clinical and prognostic impact of these innervation imaging studies in patients with heart disease, are examined. PMID:26033907

  8. Measurement of residence time distribution of liquid phase in an industrial-scale continuous pulp digester using radiotracer technique.

    PubMed

    Sheoran, Meenakshi; Goswami, Sunil; Pant, Harish J; Biswal, Jayashree; Sharma, Vijay K; Chandra, Avinash; Bhunia, Haripada; Bajpai, Pramod K; Rao, S Madhukar; Dash, A

    2016-05-01

    A series of radiotracer experiments was carried out to measure residence time distribution (RTD) of liquid phase (alkali) in an industrial-scale continuous pulp digester in a paper industry in India. Bromine-82 as ammonium bromide was used as a radiotracer. Experiments were carried out at different biomass and white liquor flow rates. The measured RTD data were treated and mean residence times in individual digester tubes as well in the whole digester were determined. The RTD was also analyzed to identify flow abnormalities and investigate flow dynamics of the liquid phase in the pulp digester. Flow channeling was observed in the first section (tube 1) of the digester. Both axial dispersion and tanks-in-series with backmixing models preceded with a plug flow component were used to simulate the measured RTD and quantify the degree of axial mixing. Based on the study, optimum conditions for operating the digester were proposed. PMID:26896681

  9. Combination of sealed source and radiotracer technique to understand malfunctioning in a chemical plant.

    PubMed

    Yelgaonkar, V N; Jayakumar, T K; Singh, Sudhir; Sharma, M K

    2009-01-01

    Pure terphthalic acid (PTA) is produced by the oxidation of paraxylene in an oxidation reactor of a PTA plant. Since the reaction is exothermic, the temperature rises above 210 degrees C. Vapours formed in the reactor are passed through a series of heat exchangers and the cooled liquid is fed back to the reactor, which flows to the reactor by gravity. In one of the heat exchangers, improper flow distribution in the inlet and outlet pipelines was suspected. Maldistribution of flow in the heat exchanger was also suspected. Gamma scanning of the pipelines and a radiotracer experiment were carried out in the heat exchanger to study the malfunctioning. A specially fabricated pipe scanner was used to scan both 24in diameter and 16in diameter pipelines. From gamma scanning of the pipelines mostly on the bends, absence of the full bore flow of the liquid was observed. Presence of vapours along with the liquid could be obstructing the liquid flow, thereby causing the malfunctioning. A radiotracer experiment was also carried out to study the flow pattern in the heat exchanger. From the experiment, mean residence time of the heat exchanger was estimated as 470s, which theoretically should be about 102s. It indicated that the flow is decelerated in the heat exchanger because of the presence of vapour lock in the tube side. PMID:19318264

  10. Effect of Cyclosporin A on the Uptake of D3-Selective PET Radiotracers in Rat Brain

    PubMed Central

    Tu, Zhude; Li, Shihong; Xu, Jinbin; Chu, Wenhua; Jones, Lynne A.; Luedtke, Robert R.; Mach, Robert H.

    2011-01-01

    Introduction Four benzamide analogs having a high affinity and selectivity for D3 versus D2 receptors were radiolabeled with 11C or 18F for in vivo evaluation. Methods Precursors were synthesized and the four D3 selective benzamide analogs were radiolabeled. The tissue distribution and brain uptake of the four compounds were evaluated in control rats and rats pretreated with cyclosporin A, a modulator of P-glycoprotein and an inhibitor of other ABC efflux transporters that contribute to the blood brain barrier. MicroPET imaging was carried out for [11C]6 in a control and a cyclosporin A pre-treated rat. Results All four compounds showed low brain uptake in control rats at 5 and 30 min post-injection; despite recently reported rat behavioral studies conducted on analogs 6 (WC-10) and 7 (WC-44). Following administration of cyclosporin A, increased brain uptake was observed with all four PET radiotracers at both 5 and 30 min post-i.v. injection. An increase in brain uptake following modulation/inhibition of the ABC transporters was also observed in the microPET study. Conclusions These data suggest that D3 selective conformationally-flexible benzamide analogs which contain a N-2-methoxyphenylpiperazine moiety are substrates for P-glycoprotein or other ABC transporters expressed at the blood-brain barrier, and that PET radiotracers containing this pharmacophore may display low brain uptake in rodents due to the action of these efflux transporters. PMID:21718948

  11. Establishment of a trimodality analytical platform for tracing, imaging and quantification of gold nanoparticles in animals by radiotracer techniques.

    PubMed

    Chen, Chien-Hung; Lin, Fong-Sian; Liao, Wei-Neng; Liang, Sanching L; Chen, Min-Hua; Chen, Yo-Wen; Lin, Wan-Yu; Hsu, Ming-Hua; Wang, Mei-Ya; Peir, Jinn-Jer; Chou, Fong-In; Chen, Ching-Ya; Chen, Sih-Yu; Huang, Su-Chin; Yang, Mo-Hsiung; Hueng, Dueng-Yuan; Hwu, Yeukuang; Yang, Chung-Shi; Chen, Jen-Kun

    2015-01-01

    This study aims to establish a (198)Au-radiotracer technique for in vivo tracing, rapid quantification, and ex vivo visualization of PEGylated gold nanoparticles (GNPs) in animals, organs and tissue dissections. The advantages of GNPs lie in its superior optical property, biocompatibility and versatile conjugation chemistry, which are promising to develop diagnostic probes and drug delivery systems. (198)Au is used as a radiotracer because it simultaneously emits beta and gamma radiations with proper energy and half-life; therefore, (198)Au can be used for bioanalytical purposes. The (198)Au-tagged radioactive gold nanoparticles ((198)Au-GNPs) were prepared simply by irradiating the GNPs in a nuclear reactor through the (197)Au(n,γ)(198)Au reaction and subsequently the (198)Au-GNPs were subjected to surface modification with polyethylene glycol to form PEGylated (198)Au-GNPs. The (198)Au-GNPs retained physicochemical properties that were the same as those of GNP before neutron irradiation. Pharmacokinetic and biodisposition studies were performed by intravenously injecting three types of (198)Au-GNPs with or without PEGylation into mice; the γ radiation in blood specimens and dissected organs was then measured. The (198)Au-radiotracer technique enables rapid quantification freed from tedious sample preparation and shows more than 95% recovery of injected GNPs. Clinical gamma scintigraphy was proved feasible to explore spatial- and temporal-resolved biodisposition of (198)Au-GNPs in living animals. Moreover, autoradiography, which recorded beta particles from (198)Au, enabled visualizing the heterogeneous biodisposition of (198)Au-GNPs in different microenvironments and tissues. In this study, the (198)Au-radiotracer technique facilitated creating a trimodality analytical platform for tracing, quantifying and imaging GNPs in animals. PMID:25424326

  12. Synthesis of Diverse (11)C-Labeled PET Radiotracers via Direct Incorporation of [(11)C]CO2.

    PubMed

    Mossine, Andrew V; Brooks, Allen F; Jackson, Isaac M; Quesada, Carole A; Sherman, Phillip; Cole, Erin L; Donnelly, David J; Scott, Peter J H; Shao, Xia

    2016-05-18

    Three new positron emission tomography (PET) radiotracers of interest to our functional neuroimaging and translational oncology programs have been prepared through new developments in [(11)C]CO2 fixation chemistry. [(11)C]QZ (glutaminyl cyclase) was prepared via a tandem trapping of [(11)C]CO2/intramolecular cyclization; [(11)C]tideglusib (glycogen synthase kinase-3) was synthesized through a tandem trapping of [(11)C]CO2 followed by an intermolecular cycloaddition between a [(11)C]isocyanate and an isothiocyanate to form the 1,2,4-thiadiazolidine-3,5-dione core; [(11)C]ibrutinib (Bruton's tyrosine kinase) was synthesized through a HATU peptide coupling of an amino precursor with [(11)C]acrylic acid (generated from [(11)C]CO2 fixation with vinylmagnesium bromide). All radiochemical syntheses are fully automated on commercial radiochemical synthesis modules and provide radiotracers in 1-5% radiochemical yield (noncorrected, based upon [(11)C]CO2). All three radiotracers have advanced to rodent imaging studies and preliminary PET imaging results are also reported. PMID:27043721

  13. In situ anion diffusion experiments using radiotracers

    NASA Astrophysics Data System (ADS)

    Jansson, Mats; Eriksen, Trygve E.

    2004-02-01

    Diffusion experiments in compacted bentonite have been carried out in situ using the borehole laboratory CHEMLAB. The "ordinary" anion iodide and the redox-sensitive pertechnetate ion have been investigated. In spite of strongly reducing groundwater conditions, technetium was found to diffuse mostly unreduced as TcO 4-, although in some spots in the compacted clay, the activity was significantly higher, which may be explained by reduction of some TcO 4- by iron-containing minerals in the bentonite. The measured concentration profiles in the clay cannot be accommodated by assuming one single diffusion process. The experimental data are modeled assuming two diffusion paths, intralamellar diffusion and diffusion in external water. The apparent diffusivity for the intralamellar diffusion was found to be 8.6×10 -11 m 2 s -1 for iodide with a capacity factor of 0.1, while the apparent diffusivity for the diffusion in external water was found to be 5×10 -14 m 2 s -1 with α=2.26. The corresponding values for Tc were found to be Da=6×10 -11 m 2 s -1, α=0.1 and Da=1×10 -13 m 2 s -1, α=0.46, respectively. The diffusion constants and capacity factors obtained in this study are in accordance with data from laboratory experiments.

  14. Discharge rate measurements in a canal using radiotracer methods.

    PubMed

    Pant, H J; Goswami, Sunil; Biswal, Jayashree; Samantray, J S; Sharma, V K

    2016-06-01

    Discharge rates of water were measured in a canal using radiotracer methods with an objective to validate the efficacy of Concrete Volute Pumps (CVPs) installed at various pumping stations along the canal. Pulse velocity and dilution methods were applied to measure the discharge rates using Iodine-131 as a radiotracer. The discharge rate measured in one of the sections of the canal using the pulse velocity method was found to be 22.5m(3)/s, whereas the discharge rates measured using the dilution method in four different sections of the canal varied from 20.27 to 20.62m(3)/s with single CVP in operation. The standard error in discharge rate measurements using dilution method ranged from ±1.1 to ±1.8%. The experimentally measured values of the discharge rate were in good agreement with the design value of the discharge rate (20m(3)/s) thus validating the performance of the CVPs used in the canal. PMID:27016711

  15. Radiotracers for Cardiac Sympathetic Innervation: Transport Kinetics and Binding Affinities for the Human Norepinephrine Transporter

    PubMed Central

    Raffel, David M.; Chen, Wei; Jung, Yong-Woon; Jang, Keun Sam; Gu, Guie; Cozzi, Nicholas V.

    2013-01-01

    Introduction Most radiotracers for imaging of cardiac sympathetic innervation are substrates of the norepinephrine transporter (NET). The goal of this study was to characterize the NET transport kinetics and binding affinities of several sympathetic nerve radiotracers, including [11C]-(−)-meta-hydroxyephedrine, [11C]-(−)-epinephrine, and a series of [11C]-labeled phenethylguanidines under development in our laboratory. For comparison, the NET transport kinetics and binding affinities of some [3H]-labeled biogenic amines were also determined. Methods Transport kinetics studies were performed using rat C6 glioma cells stably transfected with the human norepinephrine transporter (C6-hNET cells). For each radiolabeled NET substrate, saturation transport assays with C6-hNET cells measured the Michaelis-Menten transport constants Km and Vmax for NET transport. Competitive inhibition binding assays with homogenized C6-hNET cells and [3H]mazindol provided estimates of binding affinities (KI) for NET. Results Km, Vmax and KI values were determined for each NET substrate with a high degree of reproducibility. Interestingly, C6-hNET transport rates for ‘tracer concentrations’ of substrate, given by the ratio Vmax/Km, were found to be highly correlated with neuronal transport rates measured previously in isolated rat hearts (r2 = 0.96). This suggests that the transport constants Km and Vmax measured using the C6-hNET cells accurately reflect in vivo transport kinetics. Conclusion The results of these studies show how structural changes in NET substrates influence NET binding and transport constants, providing valuable insights that can be used in the design of new tracers with more optimal kinetics for quantifying regional sympathetic nerve density. PMID:23306137

  16. Study of the Efficiency of STIRAP

    NASA Astrophysics Data System (ADS)

    Sun, Yuan; Zakharov, Vladislav; Metcalf, Harold

    2014-05-01

    We measure the efficiency of the STIRAP process in exciting 23S metastable He atoms (He*) to Rydberg states. Atoms in a beam are excited to 33P by λ = 389 nm light (blue), and from there to Rydberg states by ~ 800 nm (red) light. The parallel laser beams are perpendicular to the atomic beam, arranged so that the atoms encounter the red light first (in counterintuitive order), partially overlapping with the blue. Although the lasers are CW, the atoms fly through their mm-size beams at v ~ 1070 m/s so they see μs pulses of light. The primary detection scheme uses a stainless steel detector (SSD) as a target from which He* can efficiently eject an electron. A bichromatic light beam at λ = 1083 nm exerts a strong transverse force on He* atoms that deflects them into the offset SSD, but Rydberg atoms are unaffected, thus allowing an absolute measure of the Rydberg atoms. A secondary detection method exploits the relative ease of ionizing Rydberg atoms by background blackbody radiation. The efficiency of Rydberg production is partly limited by the residual transverse velocity spread of the atomic beam, causing Doppler broadening. This will be partially remedied with an optical molasses for transverse cooling just before the STIRAP region. Supported by ONR.

  17. Design of a serotonin 4 receptor radiotracer with decreased lipophilicity for single photon emission computed tomography.

    PubMed

    Fresneau, Nathalie; Dumas, Noé; Tournier, Benjamin B; Fossey, Christine; Ballandonne, Céline; Lesnard, Aurélien; Millet, Philippe; Charnay, Yves; Cailly, Thomas; Bouillon, Jean-Philippe; Fabis, Frédéric

    2015-04-13

    With the aim to develop a suitable radiotracer for the brain imaging of the serotonin 4 receptor subtype (5-HT4R) using single photon emission computed tomography (SPECT), we synthesized and evaluated a library of di- and triazaphenanthridines with lipophilicity values which were in the range expected to favour brain penetration, and which demonstrated specific binding to the target of interest. Adding additional nitrogen atoms to previously described phenanthridine ligands exhibiting a high unspecific binding, we were able to design a radioiodinated compound [(125)I]14. This compound exhibited a binding affinity value of 0.094 nM toward human 5-HT4R and a high selectivity over other serotonin receptor subtypes (5-HTR). In vivo SPECT imaging studies and competition experiments demonstrated that the decreased lipophilicity (in comparison with our previously reported compounds 4 and 5) allowed a more specific labelling of the 5-HT4R brain-containing regions. PMID:25778994

  18. Experimental observation of silver and gold penetration into dental ceramic by means of a radiotracer technique

    SciTech Connect

    Moya, F.; Payan, J.; Bernardini, J.; Moya, E.G.

    1987-12-01

    A radiotracer technique was used to study silver and gold diffusion into dental porcelain under experimental conditions close to the real conditions in prosthetic laboratories for porcelain bakes. It was clearly shown that these non-oxidizable elements were able to diffuse into the ceramic as well as oxidizable ones. The penetration depth varied widely according to the element. The ratio DAg/DAu was about 10(3) around 850 degrees C. In contrast to gold, the silver diffusion rate was high enough to allow silver, from the metallic alloy, to be present at the external ceramic surface after diffusion into the ceramic. Hence, the greening of dental porcelains baked on silver-rich alloys could be explained mainly by a solid-state diffusion mechanism.

  19. Barriers to Industrial Energy Efficiency - Study (Appendix A), June 2015

    SciTech Connect

    2015-06-01

    This study examines barriers that impede the adoption of energy efficient technologies and practices in the industrial sector, and identifies successful examples and opportunities to overcome these barriers. Three groups of energy efficiency technologies and measures were examined: industrial end-use energy efficiency, industrial demand response, and industrial combined heat and power. This study also includes the estimated economic benefits from hypothetical Federal energy efficiency matching grants, as directed by the Act.

  20. Synthesis, characterization and application of Au-198 nanoparticles as radiotracer for industrial applications.

    PubMed

    Goswami, Sunil; Pant, H J; Biswal, Jayashree; Samantray, J S; Sharma, V K; Dash, Ashutosh

    2016-05-01

    This paper describes synthesis and characterization of radioactive gold nanoparticles ((198)Au-NPs), and explores their utility as a radiotracer for tracing an aqueous phase in a continuous laboratory-scale bubble column at ambient conditions. The performance of the (198)Au-NPs as a radiotracer was compared with the results obtained with a conventional radiotracer i.e. bromine-82 ((82)Br) as ammonium bromide and found to be identical. A tank-in-series with backmixing model (TISBM) was used to simulate the RTDs of the aqueous phase and characterize flow in the bubble column. PMID:26897465

  1. Efficiency study comparing two helicopter planetary reduction stages

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy L.; Handschuh, Robert F.

    1990-01-01

    A study was conducted to compare the efficiency of two helicopter transmission planetary reduction stages. Experimental measurements and analytical predictions were made. The analysis predicted and experiments verified that one planetary stage was a more efficient design due to the type of planet bearing used in the stage. The effects of torque, speed, lubricant type, and lubricant temperature on planetary efficiency are discussed.

  2. Operationally efficient propulsion system study (OEPSS) data book. Volume 6; Space Transfer Propulsion Operational Efficiency Study Task of OEPSS

    NASA Technical Reports Server (NTRS)

    Harmon, Timothy J.

    1992-01-01

    This document is the final report for the Space Transfer Propulsion Operational Efficiency Study Task of the Operationally Efficient Propulsion System Study (OEPSS) conducted by the Rocketdyne Division of Rockwell International. This Study task studied, evaluated and identified design concepts and technologies which minimized launch and in-space operations and optimized in-space vehicle propulsion system operability.

  3. Optimization study of the efficient spindle

    NASA Astrophysics Data System (ADS)

    Kim, Y. D.; Chun, D. H.; Kang, M. S.; Kim, H. D.

    2008-09-01

    In the field of yarn dyeing, the most generally employed method is a type of package dyeing which uses a package of cheese stacked on a spindle made of a perforated tube. Spindles up to now, have been designed without considering the characteristics of dyeing liquid, focusing only on the geometric configuration which cause many problems such as lack of level dyeing. To improve the level dyeing and find the appropriate spindle configuration for the most effective dyeing process, this study examines the spindle flow-field in detail, using a computational method. Flow characteristics inside the spindle have been investigated with varying in porosity, porous diameter and the velocity of the flow. The results show that the total pressure of the flow through the spindle is used to overcome body force. The characteristics of the flow from the porous spindle could also be observed. Based on the results from this study, an effective spindle configuration for level-dyeing has been proposed.

  4. Stress and efficiency studies in EFG

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The goals of this program were: (1) to define minimum stress configurations for silicon sheet growth at high speeds; (2) to quantify dislocation electrical activity and their limits on minority carrier diffusion length in deformed silicon; and (3) to study reasons for degradation of lifetime with increases in doping level in edge-defined film-fed growth (EFG) materials. A finite element model was developed for calculating residual stress with plastic deformation. A finite element model was verified for EFG control variable relationships to temperature field of the sheet to permit prediction of profiles and stresses encountered in EFG systems. A residual stress measurement technique was developed for finite size EFG material blanks using shadow Moire interferometry. Transient creep response of silicon was investigated in the temperature range between 800 and 1400 C in strain and strain regimes of interest in stress analysis of sheet growth. Quantitative relationships were established between minority carrier diffusion length and dislocation densities using Electron Beam Induced Current (EBIC) measurement in FZ silicon deformed in four point bending tests.

  5. Coeur d'Alene Tribe Energy Efficiency Feasibility Study

    SciTech Connect

    Allgood, Tiffany L.; Sorter, Andy

    2015-01-13

    The Coeur d'Alene Tribe's Energy Efficiency Feasibility Study (EEFS) is the culminating document that compiles the energy efficiency and building performance assessment and project prioritization process completed on 36 Tribally owned and operated facilities within Tribal lands. The EEFS contains sections on initial findings, utility billing analyses, energy conservation measures and prioritization and funding sources and strategies for energy project implementation.

  6. Studying and Incorporating Efficiency into Gastrointestinal Endoscopy Centers

    PubMed Central

    Day, Lukejohn W.; Belson, David

    2015-01-01

    Efficiency is defined as the use of resources in such a way as to maximize the production of goods and services. Improving efficiency has been the focus of management in many industries; however, it has not been until recently that incorporating efficiency models into healthcare has occurred. In particular, the study and development of improvement projects aimed at enhancing efficiency in GI have been growing rapidly in recent years. This focus on improving efficiency in GI has been spurred by the dramatic rise in the demand for endoscopic procedures as well as the rising number of insured patients requiring GI care coupled at the same time with limited resources in terms of staffing and space in endoscopy centers. This paper will critically review the history of efficiency in endoscopy centers, first by looking at other healthcare industries that have extensively studied and improved efficiency in their fields, examine a number of proposed efficiency metrics and benchmarks in endoscopy centers, and finally discuss opportunities where endoscopy centers could improve their efficiency. PMID:26101525

  7. Strategies for Energy Efficient Remodeling: SEER 2003 Case Study Report

    SciTech Connect

    2004-11-01

    The goal of the Strategies for Energy Efficiency in Remodeling (SEER) project is to provide information, based on research and case studies, to remodelers and consumers about opportunities to increase home energy performance.

  8. Fluorinated quinazolinones as potential radiotracers for imaging kinesin spindle protein expression.

    PubMed

    Holland, Jason P; Jones, Michael W; Cohrs, Susan; Schibli, Roger; Fischer, Eliane

    2013-01-15

    Anti-mitotic anti-cancer drugs offer a potential platform for developing new radiotracers for imaging proliferation markers associated with the mitosis-phase of the cell-cycle. One interesting target is kinesin spindle protein (KSP)-an ATP-dependent motor protein that plays a vital role in bipolar spindle formation. In this work we synthesised a range of new fluorinated-quinazolinone compounds based on the structure of the clinical candidate KSP inhibitor, ispinesib, and investigated their properties in vitro as potential anti-mitotic agents targeting KSP expression. Anti-proliferation (MTT and BrdU) assays combined with additional studies including fluorescence-assisted cell sorting (FACS) analysis of cell-cycle arrest confirmed the mechanism and potency of these biphenyl compounds in a range of human cancer cell lines. Additional studies using confocal fluorescence microscopy showed that these compounds induce M-phase arrest via monoaster spindle formation. Structural studies revealed that compound 20-(R) is the most potent fluorinated-quinazolinone inhibitor of KSP and represents a suitable lead candidate for further studies on designing (18)F-radiolabelled agents for positron-emission tomography (PET). PMID:23245569

  9. The Synthesis and Evaluations of the 68Ga-Lissamine Rhodamine B (LRB) as a New Radiotracer for Imaging Tumors by Positron Emission Tomography

    PubMed Central

    Li, Xuena; Yin, Yafu; Du, Bulin; Li, Na; Li, Yaming

    2016-01-01

    Purpose. The aim of this study is to synthesize and evaluate 68Ga-labeled Lissamine Rhodamine B (LRB) as a new radiotracer for imaging MDA-MB-231 and MCF-7 cells induced tumor mice by positron emission tomography (PET). Methods. Firstly, we performed the radio synthesis and microPET imaging of 68Ga(DOTA-LRB) in athymic nude mice bearing MDA-MB-231 and MCF-7 human breast cancer xenografts. Additionally, the evaluations of 18F-fluorodeoxyglucose (FDG), as a glucose metabolism radiotracer for imaging tumors in the same xenografts, have been conducted as a comparison. Results. The radiochemical purity of 68Ga(DOTA-LRB) was >95%. MicroPET dynamic imaging revealed that the uptake of 68Ga(DOTA-LRB) was mainly in normal organs, such as kidney, heart, liver, and brain and mainly excreted from kidney. The MDA-MB-231 and MCF-7 tumors were not clearly visible in PET images at 5, 15, 30, 40, 50, and 60 min after injection of 68Ga(DOTA-LRB). The tumor uptake values of 18F-FDG were 3.79 ± 0.57 and 1.93 ± 0.48%ID/g in MDA-MB-231 and MCF-7 tumor xenografts, respectively. Conclusions. 68Ga(DOTA-LRB) can be easily synthesized with high radiochemical purity and stability; however, it may be not an ideal PET radiotracer for imaging of MDR-positive tumors. PMID:26949707

  10. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    NASA Astrophysics Data System (ADS)

    Kiser, Matthew R.

    be introduced to plants as biologically active molecules such as 11CO2, N13O-3, 18F--[H2O], and H152O . Plants for these studies are grown in controlled-environment chambers at the Phytotron. The chambers offer an array of control for temperature, humidity, atmospheric CO2 concentration, and light intensity. Additionally, the Phytotron houses one large reach-in growth chamber that is dedicated to this project for radioisotope labeling measurements. There are several important properties of short-lived positron-emitting radio-tracers that make them well suited for use in investigating metabolite transport in plants. First, because the molecular mass of a radioisotope-tagged compound is only minutely different from the corresponding stable compound, radiotracer substances should be metabolized and transported in plants the same as their non-radioactive counterparts. Second, because the relatively high energy gamma rays emitted from electron-positron annihilation are attenuated very little by plant tissue, the real-time distribution of a radiotracer can be measured in vivo in plants. Finally, the short radioactive half-lives of these isotopes allow for repeat measurements on the same plant in a short period of time. For example, in studies of short-term environmental changes on plant metabolite dynamics, a single plant can be labeled multiple times to measure its responses to different, environmental conditions. Also, different short-lived radiotracers can be applied to the same plant over a short period of time to investigate the transport and allocation of various metabolites. This newly developed system provides the capabilities for production of 11CO2 at TUNL, transfer of the 11CO 2 gas from the target area at TUNL to a radiation-shielded cryogenic trap at the Phytotron, labeling of photoassimilates with 11C, and in vivo gamma-ray detection for real-time measurements of the radiotracer distribution in small plants. The experimental techniques and instrumentation

  11. Methods of Efficient Study Habits and Physics Learning

    NASA Astrophysics Data System (ADS)

    Zettili, Nouredine

    2010-02-01

    We want to discuss the methods of efficient study habits and how they can be used by students to help them improve learning physics. In particular, we deal with the most efficient techniques needed to help students improve their study skills. We focus on topics such as the skills of how to develop long term memory, how to improve concentration power, how to take class notes, how to prepare for and take exams, how to study scientific subjects such as physics. We argue that the students who conscientiously use the methods of efficient study habits achieve higher results than those students who do not; moreover, a student equipped with the proper study skills will spend much less time to learn a subject than a student who has no good study habits. The underlying issue here is not the quantity of time allocated to the study efforts by the students, but the efficiency and quality of actions so that the student can function at peak efficiency. These ideas were developed as part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), an outreach grant funded by the Alabama Commission on Higher Education. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. )

  12. Cyclotron production of ``very high specific activity'' platinum radiotracers in No Carrier Added form

    NASA Astrophysics Data System (ADS)

    Birattari, C.; Bonardi, M.; Groppi, F.; Gini, L.; Gallorini, M.; Sabbioni, E.; Stroosnijder, M. F.

    2001-12-01

    At the "Radiochemistry Laboratory" of Accelerators and Applied Superconductivity Laboratory, LASA, several production and quality assurance methods for short-lived and high specific activity radionuclides, have been developed. Presently, the irradiations are carried out at the Scanditronix MC40 cyclotron (K=38; p, d, He-4 and He-3) of JRC-Ispra, Italy, of the European Community, while both chemical purity and specific activity determination are carried out at the TRIGA MARK II research reactor of University of Pavia and at LASA itself. In order to optimize the irradiation conditions for platinum radiotracer production, both thin- and thick-target excitation function of natOs(α,xn) nuclear reactions were measured. A very selective radiochemical separation to obtain Pt radiotracers in No Carrier Added form, has been developed. Both real specific activity and chemical purity of radiotracer, have been determined by neutron activation analysis and atomic absorption spectrometry. An Isotopic Dilution Factor (IDF) of the order of 50 is achieved.

  13. Distributed Microprocessor Automation Network for Synthesizing Radiotracers Used in Positron Emission Tomography [PET

    DOE R&D Accomplishments Database

    Russell, J. A. G.; Alexoff, D. L.; Wolf, A. P.

    1984-09-01

    This presentation describes an evolving distributed microprocessor network for automating the routine production synthesis of radiotracers used in Positron Emission Tomography. We first present a brief overview of the PET method for measuring biological function, and then outline the general procedure for producing a radiotracer. The paper identifies several reasons for our automating the syntheses of these compounds. There is a description of the distributed microprocessor network architecture chosen and the rationale for that choice. Finally, we speculate about how this network may be exploited to extend the power of the PET method from the large university or National Laboratory to the biomedical research and clinical community at large. (DT)

  14. Measurement of leaching from simulated nuclear-waste glass using radiotracers

    SciTech Connect

    Bates, J.K.; Jardine, L.J.; Steindler, M.J.

    1982-09-01

    The use of radiotracer spiking as a method of measuring the leaching from simulated nuclear-waste glass is shown to give results comparable with other analytical detection methods. The leaching behavior of /sup 85/Sr, /sup 106/Ru, /sup 133/Ba, /sup 137/Cs, /sup 141/Ce, /sup 152/Eu, and other isotopes is measured for several defense waste glasses. These tests show that radiotracer spiking is a sensitive, multielement technique that can provide leaching data, for actual waste elements, that are difficult to obtain by other methods. Additionally, a detailed procedure is described that allows spiked glass to be prepared with a suitable distribution of radionuclides.

  15. Biochemical quantification of sympathetic nervous activity in humans using radiotracer methodology: fallibility of plasma noradrenaline measurements

    SciTech Connect

    Esler, M.; Leonard, P.; O'Dea, K.; Jackman, G.; Jennings, G.; Korner, P.

    1982-01-01

    We have developed radiotracer techniques for studying noradrenaline kinetics, to assess better sympathetic nervous system function in humans. Tritiated l-noradrenaline was infused intravenously (0.35 microCi/m2/min) to plateau plasma concentration. Noradrenaline plasma clearance was calculated from plasma tritiated noradrenaline concentration at steady state, and the rate of spillover of noradrenaline to plasma derived from plasma noradrenaline specific radioactivity. Mean noradrenaline spillover at rest in 34 normal subjects was 0.33 micrograms/m2/min (range 0.17-0.61 micrograms/m2/min). Predictably, noradrenaline spillover was reduced in patients with subnormal sympathetic nervous system activity, 0.16 +/- 0.09 micrograms/m2/min in eight patients with idiopathic peripheral autonomic insufficiency, and 0.11 +/- 0.07 micrograms/m2/min (mean +/- SD) in six patients with essential hypertension treated with clonidine (0.45 mg daily). Noradrenaline line plasma clearance in normal subjects was 1.32 +/- 0.28 L/m2/min. Clearance fell with age, causing the previously described rise in plasma noradrenaline concentration with aging. Unexpected effects of drugs were encountered, for example chronic beta-adrenergic blockade in patients with essential hypertension reduced noradrenaline clearance. Plasma noradrenaline concentration measurements were not in agreement with noradrenaline release rate values, and do not reliably indicate sympathetic nervous system activity, in instances such as these where noradrenaline clearance is abnormal.

  16. Investigating phosphorus uptake in anoxic and sulfidic surface sediments with 33P radiotracer experiments

    NASA Astrophysics Data System (ADS)

    Dijkstra, Nikki; Kraal, Peter; Gonzalez, Santiago; Slomp, Caroline

    2016-04-01

    Phosphorus (P) is a key nutrient for marine organisms. Enhanced P availability in the water column can fuel algal blooms and the development of bottom water anoxia. Recently, it was suggested that micro-organisms in sediments overlain by anoxic and sulfidic bottom waters might take up dissolved P and form Fe(II)-P minerals, thereby enhancing P removal. In this study, we investigated the uptake of P in surface sediments with 33P radiotracer experiments. The sediments were recovered from the anoxic and sulfidic deep basin of the Black Sea and, for comparison, from the adjacent oxic shelf. Results suggest a very fast sedimentary uptake of 33P at all sites but in particular for sediments from the oxic shelf. At all sites, most 33P was sequestered in the citrate-dithionite-bicarbonate-(CDB)-extractable sediment P fraction. No significant differences with abiotic controls were observed, implying that micro-organisms were not directly involved in the P uptake. Whereas 33P uptake by the oxic shelf sediment was likely controlled by sorption of 33P to iron(Fe)-(oxyhydr)oxides, the nature of the CDB-extractable P fraction in the deep basin sediments remains unclear. We discuss whether authigenic formation of Fe(II)-P minerals or fast adsorption of P to calcites may explain our findings.

  17. Design and evaluation of radiotracers for determination of regional cerebral blood flow with PET

    SciTech Connect

    Lambrecht, R.M.; Duncan, C.C.; Shiue, C.Y.

    1982-01-01

    The tracer kinetics of 4-Fluoro(/sup 18/F)-, 4-Bromo(/sup 82/Br)- and 4-Iodo(/sup 125/I)-antipyrine and /sup 15/O-water were compared in a cat or baboon animal model. First-pass cerebral extraction and clearance with alterations in PaCO/sub 2/ were measured for whole brain. The Renkin/Crone model was used to evaluate brain capillary permeability-surface area product for 4-/sup 18/FAP in cats. Positron-emission-tomographic measurements required development of an instrument and technique for control of the arterial concentration of the radiotracer as a ramp function, so that tracer concentration changes due to radioactive decay or altered physiological processes could be accurately described with PET. Pharmacokinetic and tissue-distribution studies in cats were used to determine dosimetry for 4-/sup 18/FAP. 4-Bromoantipyrine labeled with /sup 78/Br (t = 6.5 m) is suggested as a tracer for determination of rCBF with PET.

  18. Numerical study of efficiency for a 670 GHz gyrotron

    SciTech Connect

    Pu Ruifeng; Nusinovich, Gregory S.; Sinitsyn, Oleksandr V.; Antonsen, Thomas M. Jr.

    2011-02-15

    In this paper, the results of the efficiency study of a 670 GHz gyrotron operating at TE{sub 31,8}-mode are presented. Calculations are performed by using the self-consistent nonstationary code MAGY. Three cavity configurations were examined. The effects of ohmic losses and electron velocity spread were included in the simulation. The results show that the output efficiency can reach 35% and the velocity spread in the electron beam does not degrade the operation significantly. Furthermore, we verified that the smoothing of the sharp corners for a small tapering angle would reduce mode conversion; the parasitic excitation of neighboring radial modes is less than 1% of the amplitude of the operating mode and the effect on efficiency is small. Lastly, the simulation results show that the after-cavity interaction causes only slight variations in the efficiency.

  19. A Study of Visual Efficiency Necessary for Beginning Reading.

    ERIC Educational Resources Information Center

    Young, Beverly S.; And Others

    A study was conducted to determine if there were significant differences in vision between beginning readers who learn to read easily and those who learn with difficulty (dyslexics). In addition, the study examined the mean of the high achievers (rather than expert opinion) to discover the degree to which visual efficiency was normally needed for…

  20. Efficiency of Social Studies Integrated Character Education Program

    ERIC Educational Resources Information Center

    Katilmis, Ahmet; Eksi, Halil; Ozturk, Cemil

    2011-01-01

    In this research, it is aimed to find out (i) the efficiency of a character education program based on overt values of Turkish 7th grade social studies lesson, and (ii) its hidden effects on the academic success. This research employed a semi-experimental design with pre-test, post-test and control group For this research primarily character…

  1. Energy-Efficient Schools: Three Case Studies from Oregon.

    ERIC Educational Resources Information Center

    2003

    This document presents case studies of three schools or districts in Oregon that have implemented steps to promote energy efficiency. Steps taken by the schools include daylighting, energy audits, special energy loans, new ventilation design, and sustainable building practices. The facilities described are Ash Creek Intermediate School in…

  2. Energy Efficiency of Higher Education Buildings: A Case Study

    ERIC Educational Resources Information Center

    Soares, Nelson; Pereira, Luísa Dias; Ferreira, João; Conceição, Pedro; da Silva, Patrícia Pereira

    2015-01-01

    Purpose: This paper aims to propose an energy efficiency plan (with technical and behavioural improvement measures) for a Portuguese higher education building--the Teaching Building of the Faculty of Economics of the University of Coimbra (FEUC). Design/methodology/approach: The study was developed in the context of both the "Green…

  3. [(18)F]-Group 13 fluoride derivatives as radiotracers for positron emission tomography.

    PubMed

    Chansaenpak, Kantapat; Vabre, Boris; Gabbaï, François P

    2016-02-21

    The field of (18)F chemistry is rapidly expanding because of the use of this radionuclide in radiotracers for positron emission tomography (PET). Until recently, most [(18)F]-radiotracers were generated by the direct attachment of (18)F to a carbon in the organic backbone of the radiotracer. The past decade has witnessed the emergence of a new strategy based on the formation of an (18)F-group 13 element bond. This approach, which is rooted in the field of fluoride anion complexation/coordination chemistry, has led to the development of a remarkable family of boron, aluminium and gallium [(18)F]-fluoride anion complexing agents which can be conjugated with peptides and small molecules to generate disease specific PET radiotracers. This review is dedicated to the chemistry of these group 13 [(18)F]-fluorides anion complexing agents and their use in PET. Some of the key fluoride-binding motifs covered in this review include the trifluoroborate unit bound to neutral or cationic electron deficient backbones, the BF2 unit of BODIPY dyes, and AlF or GaF3 units coordinated to multidentate Lewis basic ligands. In addition to describing how these moieties can be converted into their [(18)F]-analogs, this review also dicusses their incorporation into bioconjugates for application in PET. PMID:26548467

  4. Use of supercritical carbon dioxide fluid as a solvent for the purification of pet radiotracers

    SciTech Connect

    Ferrieri, R.A.; Fowler, J.S.; Wolf, A.P.

    1993-12-31

    We have identified superfluid chromatography (SFC) as a promising method which could offer advantages in radiotracer purification through rapid separation, as well as, improved recovery and purity of labeled product. Using SF CO{sub 2} as the mobile phase for chromatographic separation of labeled product would eliminate the need for solvent removal from product prior to delivery.

  5. An Investigation of the Effectiveness of Radiotracer Techniques for Instruction in Microbiology.

    ERIC Educational Resources Information Center

    Hurlburt, Evelyn McClelland

    Students in a junior college microbiology course were randomly assigned to one of two laboratory treatments: one using radiotracer techniques to investigate aspects of microbial metabolism, and the other using conventional techniques to investigate the same metabolic features. An achievement test administered at the completion of the unit and six…

  6. Radiolabeled multimeric cyclic RGD peptides as integrin alphavbeta3 targeted radiotracers for tumor imaging.

    PubMed

    Liu, Shuang

    2006-01-01

    Integrin alphavbeta3 plays a significant role in tumor angiogenesis and is a receptor for the extracellular matrix proteins with the exposed arginine-glycine-aspartic (RGD) tripeptide sequence. These include vitronectin, fibronectin, fibrinogen, lamin, collagen, Von Willibrand's factor, osteoponin, and adenovirus particles. Integrin alphavbeta3 is expressed at low levels on epithelial cells and mature endothelial cells, but it is overexpressed on the activated endothelial cells of tumor neovasculature and some tumor cells. The highly restricted expression of integrin alphavbeta3 during tumor growth, invasion, and metastasis presents an interesting molecular target for both early detection and treatment of rapidly growing solid tumors. In the past decade, many radiolabeled linear and cyclic RGD peptide antagonists have been evaluated as the integrin alphavbeta3 targeted radiotracers. Significant progress has been made on their use for imaging tumors of different origin by single photon emission computed tomography (SPECT) or positron emission tomography (PET) in several tumor-bearing animal models. [18F]Galacto-RGD is under clinical investigation as the first integrin alphavbeta3 targeted radiotracer for noninvasive visualization of the activated integrin alphavbeta3 in cancer patients. This review will focus on the radiolabeled multimeric cyclic RGD peptides (dimers and tetramers) useful as radiotracers to image the tumor integrin alphavbeta3 expression by SPECT and PET, and some fundamental aspects for the development of integrin alphavbeta3 targeted radiotracers. These include the choice of radionuclide and bifunctional chelators, selection of targeting biomolecules, and factors influencing the integrin alphavbeta3 binding affinity and tumor uptake, as well as different approaches for modification of radiotracer pharmacokinetics. PMID:17009846

  7. Operationally Efficient Propulsion System Study (OEPSS) data book. Executive summary

    NASA Technical Reports Server (NTRS)

    Wong, George S.

    1990-01-01

    The study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) program, the results of the Operationally Efficient Propulsion System Study (OEPSS) were organized into a series of OEPSS Data Books as follows: Volume 1, Generic Ground Operations Data; Volume 2, Ground Operations Problems; Volume 3, Operations Technology; Volume 4, OEPSS Design Concepts; and Volume 5, OEPSS Final Review Briefing, which summarizes the activities and results of the study. Summarized here are the salient results of the first year. A synopsis of each volume listed above is presented.

  8. SU-E-I-80: Beta-Minus Emitting Radiotracers Improves Molecular Endoscopy

    SciTech Connect

    Carpenter, C; Ma, X; Sun, C; Pratx, G; Cheng, Z; Xing, L

    2014-06-01

    Purpose: Molecular Endoscopy using Cerenkov Luminescence can be used to monitor the distribution of many clinically-available PET and SPECT probes for endoscopic applications. A main limitation of Cerenkov is its limited sensitivity to small concentrations of radiotracer when using light guides s. Herein we demonstrate that the use of a high energy beta emitting radioisotope, exemplified here with 90Y provides superior sensitivity to 18F because of its higher light output and its lack of corresponding gamma emission. Methods: A series of phantom experiments were performed to compare the sensitivity and noise of the CLE system for imaging 90Y and 18F. Three vials of known concentrations of 90Y (0.008 μCi, 0.08 μCi, 1 μCi) were placed in centrifuge tubes and isolated from each other. One vial of 18F (100 μCi) was placed in the imaging chamber and imaged over the course of decay (19 hours, 43 minutes, or ∼10 half-lives). Image time-points were formed from 5-minute integrations. Results: Using an SNR of 10 to define the noise-floor, the 90Y minimum detectable activity was 0.056 μCi. To the contrast, the minimum detectable activity for 18F was 11.63 μCi. These data demonstrate a 207-fold improvement in SNR of 90Y compared to 18F, when controlled for activity. Conclusion: This study demonstrated that a pure β- radionuclide such as 90Y be used is superior to 18F for Cerenkov Endoscopy. Further study is needed to demonstrate its utility in preclinical studies, endoscopic applications, intraoperative, and radiotherapy applications.

  9. Operationally Efficient Propulsion System Study (OEPSS): OEPSS Video Script

    NASA Technical Reports Server (NTRS)

    Wong, George S.; Waldrop, Glen S.; Trent, Donnie (Editor)

    1992-01-01

    The OEPSS video film, along with the OEPSS Databooks, provides a data base of current launch experience that will be useful for design of future expendable and reusable launch systems. The focus is on the launch processing of propulsion systems. A brief 15-minute overview of the OEPSS study results is found at the beginning of the film. The remainder of the film discusses in more detail: current ground operations at the Kennedy Space Center; typical operations issues and problems; critical operations technologies; and efficiency of booster and space propulsion systems. The impact of system architecture on the launch site and its facility infrastucture is emphasized. Finally, a particularly valuable analytical tool, developed during the OEPSS study, that will provide for the "first time" a quantitative measure of operations efficiency for a propulsion system is described.

  10. a Study of High Efficiency Thin Thermophotovoltaic Solar Cells.

    NASA Astrophysics Data System (ADS)

    Vera, Eduardo Sobrino

    1982-05-01

    High conversion efficiency of solar energy into electrical energy is possible if the incident radiation is first absorbed by an intermediate absorber and then re-emitted onto a photovoltaic (PV) solar cell. This mode of operation is known as solar thermophotovoltaic (TPV) energy conversion. This thesis explores the limits on performance of TPV systems based on germanium in which the source temperature and the opto-electronic structure of the germanium PV cell are varied and optimized with respect to overall radiant energy conversion efficiency. The principal characteristic of the optimized high efficiency TPV germanium cells is that they are thin p-n junction solar cells which incorporate minority carrier mirrors (MCM) and optical mirrors (OM) at the front and back surfaces of the device examined. In this study, the role of MCM and OM is studied theoretically by solving the minority carrier diffusion equation in the n- and p-type quasineutral regions of the cell with the appropriate boundary conditions at the end of these regions and an appropriate minority carrier generation function. The high theoretical efficiency calculated for these thin structures derives from the simultaneous use of optical and electronic reflection. The calculations presented here determine the theoretical upper limit to TPV conversion efficiency and show the dependence of this limit on cell geometry, resistivity, surface recombination and input density. In addition, TPV systems based on more than one PV cell, each utilizing a different photovoltaically active semiconductor are also considered. A number of possible TPV systems are treated within this theoretical framework. When blackbody thermal radiation sources having temperatures in the range 1500-2000 C are considered, the upper limit efficiency is found to be about 22% for an optimum design germanium cell 90 microns thick and about 26% for a two-junction silicon-germanium tandem cell arrangement 50 and 90 microns thick, respectively

  11. Economic impact study of consumer product efficiencies. Final report

    SciTech Connect

    Not Available

    1980-05-30

    The economic impact study of household appliance efficiencies is briefly reported. Task I, Direct Impact on Industry, contains 4 subtasks: materials, labor inputs, energy inputs, and investment. Task II, Direct Impact on Consumers, contains 3 subtasks: life-cycle cost to the consumer, usage patterns, and long-term demand forecast and analysis. The 2 subtasks in Task III, Energy Savings and Impact on Utilities, are residential energy savings and cost and impact on utility generating capacity.

  12. Evaluation of 64Cu-Labeled Acridinium Cation: A PET Radiotracer Targeting Tumor Mitochondria

    PubMed Central

    Zhou, Yang; Kim, Young-Seung; Shi, Jiyun; Jacobson, Orit; Chen, Xiaoyuan; Liu, Shuang

    2011-01-01

    This report presents the synthesis and evaluations of 64Cu(DO3A-xy-ACR) (DO3A-xy-ACR = 2,6-bis(dimethylamino)-10-(4-((4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-1-yl)methyl)benzyl)acridin-10-ium) as a radiotracer for imaging tumors in athymic nude mice bearing U87MG glioma xenografts by PET (positron emission tomography). The biodistribution data suggested that 64Cu(DO3A-xy-ACR) was excreted mainly through the renal system with >65% of injected radioactivity being recovered from urine samples at 1 h post-injection (p.i.). The tumor uptake of 64Cu(DO3A-xy-ACR) was 1.07 ± 0.23, 1.58 ± 0.55, 2.71 ± 0.66, 3.47 ± 1.19, and 3.52 ± 1.72 %ID/g at 0.5, 1, 2, 4 and 24 h p.i., respectively. 64Cu(DO3A-xy-ACR) had very high liver uptake (31.90 ± 3.98, 24.95 ± 5.64, 15.20 ± 4.29, 14.09 ± 6.82, and 8.18 ± 1.27 %ID/g at 0.5, 1, 2, 4 and 24 h p.i., respectively) with low tumor/liver ratios. MicroPET studies showed that the tumors were clearly visualized as early as 30 min p.i. in the glioma-bearing mouse administered with 64Cu(DO3A-xy-ACR). The high liver radioactivity accumulation was also seen. 64Cu(DO3A-xy-ACR) had a relatively high metabolic stability during excretion via both renal and hepatobiliary routes; but it was completely decomposed in the liver homogenate. We explored the localization mechanism of Cu(DO3A-xy-ACR) using both U87MG human glioma and the cultured primary U87MG glioma cells. The results from the cellular staining assays showed that 64Cu(DO3A-xy-ACR) is able to localize in the mitochondria of living U87MG glioma cells due to the enhanced negative mitochondrial potential as compared to normal cells. Although 64Cu(DO3A-xy-ACR) is not an ideal PET radiotracer for tumor imaging due to its high liver uptake, the results from this study strongly suggest that 64Cu-labeled acridinium cations are indeed able to localize in the energized mitochondria of tumor cells. PMID:21413736

  13. A study of IMRT planning parameters on planning efficiency, delivery efficiency, and plan quality

    SciTech Connect

    Mittauer, Kathryn; Lu Bo; Yan Guanghua; Kahler, Darren; Amdur, Robert; Liu Chihray; Gopal, Arun

    2013-06-15

    Purpose: To improve planning and delivery efficiency of head and neck IMRT without compromising planning quality through the evaluation of inverse planning parameters.Methods: Eleven head and neck patients with pre-existing IMRT treatment plans were selected for this retrospective study. The Pinnacle treatment planning system (TPS) was used to compute new treatment plans for each patient by varying the individual or the combined parameters of dose/fluence grid resolution, minimum MU per segment, and minimum segment area. Forty-five plans per patient were generated with the following variations: 4 dose/fluence grid resolution plans, 12 minimum segment area plans, 9 minimum MU plans, and 20 combined minimum segment area/minimum MU plans. Each plan was evaluated and compared to others based on dose volume histograms (DVHs) (i.e., plan quality), planning time, and delivery time. To evaluate delivery efficiency, a model was developed that estimated the delivery time of a treatment plan, and validated through measurements on an Elekta Synergy linear accelerator. Results: The uncertainty (i.e., variation) of the dose-volume index due to dose calculation grid variation was as high as 8.2% (5.5 Gy in absolute dose) for planning target volumes (PTVs) and 13.3% (2.1 Gy in absolute dose) for planning at risk volumes (PRVs). Comparison results of dose distributions indicated that smaller volumes were more susceptible to uncertainties. The grid resolution of a 4 mm dose grid with a 2 mm fluence grid was recommended, since it can reduce the final dose calculation time by 63% compared to the accepted standard (2 mm dose grid with a 2 mm fluence grid resolution) while maintaining a similar level of dose-volume index variation. Threshold values that maintained adequate plan quality (DVH results of the PTVs and PRVs remained satisfied for their dose objectives) were 5 cm{sup 2} for minimum segment area and 5 MU for minimum MU. As the minimum MU parameter was increased, the number of

  14. Improving AMS Detection of the Biomedical Radiotracer 41Ca with Segmented Radio-Frequency Quadrupoles

    NASA Astrophysics Data System (ADS)

    Alary, Jean-Francois; Javahery, Gholamreza; Kieser, William E.; Litherland, Albert E.; Cousins, Lisa M.

    41Ca is an important biomedical radiotracer finding many applications in biological, nutritional and medical studies. The detection of 41Ca by AMS is however limited by an important background signal of 41K originating from biological samples and from contaminated cesium in the source. An approach consisting of using PbF2-assisted in-source fluorination in combination with an Isobar Separator for Anions (ISA), a device incorporating a low energy radio frequency quadrupole (RFQ) gas cell, promises to push down the limit of detection of 41Ca attainable on small (<3 MV) accelerator mass spectrometry (AMS) systems by several orders of magnitude. Such on-line reduction of 41K should also result in a simplification of biological sample preparation and less concern about variable 41K contamination of the cesium beam. The selective collision-induced fragmentation of KF3- versus CaF3-, occurring in the gas cell of an ISA equipped with a double segment RFQ, have been reported earlier1), leading to K being suppressed by a factor of 1e4 over Ca. We present here the future configuration of the ISA, redesigned using multi-segmented RFQ to enhance further this effect and improve transmission through the gas cell. A segmented RFQ is an appropriate tool to finely control ion energy down to the few eV's separating the fragmentation energies of the two fluoride species. This pre-commercial ISA destined to be used at the newly established A. E. Lalonde AMS laboratory at University of Ottawa (Canada) will be presented. Some practicalities of integrating a low energy RFQ-based device in a high energy AMS system will also be discussed.

  15. Aircraft energy efficiency laminar flow control wing design study

    NASA Technical Reports Server (NTRS)

    Bonner, T. F., Jr.; Pride, J. D., Jr.; Fernald, W. W.

    1977-01-01

    An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft.

  16. In vivo imaging of beta cells with radiotracers: state of the art, prospects and recommendations for development and use.

    PubMed

    Eriksson, Olof; Laughlin, Maren; Brom, Maarten; Nuutila, Pirjo; Roden, Michael; Hwa, Albert; Bonadonna, Riccardo; Gotthardt, Martin

    2016-07-01

    Radiotracer imaging is characterised by high in vivo sensitivity, with a detection limit in the lower picomolar range. Therefore, radiotracers represent a valuable tool for imaging pancreatic beta cells. High demands are made of radiotracers for in vivo imaging of beta cells. Beta cells represent only a small fraction of the volume of the pancreas (usually 1-3%) and are scattered in the tiny islets of Langerhans throughout the organ. In order to be able to measure a beta cell-specific signal, one has to rely on highly specific tracer molecules because current in vivo imaging technologies do not allow the resolution of single islets in humans non-invasively. Currently, a considerable amount of preclinical data are available for several radiotracers and three are under clinical evaluation. We summarise the current status of the evaluation of these tracer molecules and put forward recommendations for their further evaluation. PMID:27094935

  17. Cutting Efficiency of Instruments with Different Movements: a Comparative Study

    PubMed Central

    Plotino, Gianluca; Al-Sudani, Dina; Rubini, Alessio Giansiracusa; Sannino, Gianpaolo; Piasecki, Lucila; Putortì, Ermanno; Testarelli, Luca; Gambarini, Gianluca

    2015-01-01

    ABSTRACT Objectives The aim of the present study was to evaluate the cutting efficiency of two new reciprocating instruments, Twisted File Adaptive and WaveOne Primary. Material and Methods 10 new Twisted File Adaptive (TF Adaptive) (SybronEndo, Glendora, CA, USA) and 10 new WaveOne Primary files (Dentsply Maillefer, Ballaigues, Switzerland) were activated using a torque-controlled motor, respectively TFA motor (SybronEndo, Glendora, CA, USA) and Silver motor (VDW, Munich, Germany). The device used for the cutting test consisted on a mainframe to which a mobile plastic support for the hand-piece is connected and a stainless-steel block containing a Plexiglas block against which the cutting efficiency of the instruments was tested. The length of the block cut in 1 minute was measured in a computerized program with a precision of 0.1 mm. Mean and standard deviations of each group were calculated and data were statistically analyzed with one-way ANOVA and Bonferroni t test (P < 0.05). Results TF Adaptive displayed significantly greater maximum penetration depth than WaveOne Primary (P < 0.05). In fact, TF Adaptive instruments (Group 1) cut the Plexiglas block to a mean depth of 8.7 (SD 0.5) mm, while WaveOne Primary instruments cut the Plexiglas block to a mean depth of 6.4 (SD 0.3) mm. Conclusions Twisted File Adaptive instruments demonstrated statistically higher cutting efficiency than WaveOne instruments. PMID:25937877

  18. Scintillator efficiency study with MeV x-rays

    NASA Astrophysics Data System (ADS)

    Baker, Stuart; Brown, Kristina; Curtis, Alden; Lutz, Stephen S.; Howe, Russell; Malone, Robert; Mitchell, Stephen; Danielson, Jeremy; Haines, Todd; Kwiatkowski, Kris

    2014-09-01

    We have investigated scintillator efficiency for MeV radiographic imaging. This paper discusses the modeled detection efficiency and measured brightness of a number of scintillator materials. An optical imaging camera records images of scintillator emission excited by a pulsed x-ray machine. The efficiency of various thicknesses of monolithic LYSO:Ce (cerium-doped lutetium yttrium orthosilicate) are being studied to understand brightness and resolution trade-offs compared with a range of micro-columnar CsI:Tl (thallium-doped cesium iodide) scintillator screens. The micro-columnar scintillator structure apparently provides an optical gain mechanism that results in brighter signals from thinner samples. The trade-offs for brightness versus resolution in monolithic scintillators is straightforward. For higher-energy x-rays, thicker materials generally produce brighter signal due to x-ray absorption and the optical emission properties of the material. However, as scintillator thickness is increased, detector blur begins to dominate imaging system resolution due to the volume image generated in the scintillator thickness and the depth of field of the imaging system. We employ a telecentric optical relay lens to image the scintillator onto a recording CCD camera. The telecentric lens helps provide sharp focus through thicker-volume emitting scintillators. Stray light from scintillator emission can also affect the image scene contrast. We have applied an optical light scatter model to the imaging system to minimize scatter sources and maximize scene contrasts.

  19. (Findings of the Costa Rica power sector efficiency study)

    SciTech Connect

    Waddle, D.B.

    1990-10-08

    To present findings of the Costa Rica Power Sector Efficiency Study to the Instituto Costarricense de Electridad, and to the Ministry of Energy, Natural Resources and Mining. To discuss the progress and plans for the Central American Rural Electrification Project with US Agency for International Development (USAID)/Regional Office Central American Program (ROCAP). I traveled to San Jose, Costa Rica to present the findings of the Costa Rica Power Sector Efficiency Study to our counterparts in the utility and the Ministry of Energy. Discussions were held with line level managers at Instituto Costarricensede Electricidad (ICE) and Ministry of Energy Mines and Natural Resources (MIRENEM), as well as a plan of action set for the final stage of the project. Discussions were held for a one day period with both the bilateral Agency for International Development (AID) and the regional AID mission regarding the need for a similar study in Guatemala and matters directly pertaining to the Central American Rural Electrification Study (CARES) project.

  20. Batch-reactor microfluidic device: first human use of a microfluidically produced PET radiotracer.

    PubMed

    Lebedev, Artem; Miraghaie, Reza; Kotta, Kishore; Ball, Carroll E; Zhang, Jianzhong; Buchsbaum, Monte S; Kolb, Hartmuth C; Elizarov, Arkadij

    2013-01-01

    The very first microfluidic device used for the production of (18)F-labeled tracers for clinical research is reported along with the first human Positron Emission Tomography scan obtained with a microfluidically produced radiotracer. The system integrates all operations necessary for the transformation of [(18)F]fluoride in irradiated cyclotron target water to a dose of radiopharmaceutical suitable for use in clinical research. The key microfluidic technologies developed for the device are a fluoride concentration system and a microfluidic batch reactor assembly. Concentration of fluoride was achieved by means of absorption of the fluoride anion on a micro ion-exchange column (5 μL of resin) followed by release of the radioactivity with 45 μL of the release solution (95 ± 3% overall efficiency). The reactor assembly includes an injection-molded reactor chip and a transparent machined lid press-fitted together. The resulting 50 μL cavity has a unique shape designed to minimize losses of liquid during reactor filling and liquid evaporation. The cavity has 8 ports for gases and liquids, each equipped with a 2-way on-chip mechanical valve rated for pressure up to 20.68 bar (300 psi). The temperature is controlled by a thermoelectric heater capable of heating the reactor up to 180 °C from RT in 150 s. A camera captures live video of the processes in the reactor. HPLC-based purification and reformulation units are also integrated in the device. The system is based on "split-box architecture", with reagents loaded from outside of the radiation shielding. It can be installed either in a standard hot cell, or as a self-shielded unit. Along with a high level of integration and automation, split-box architecture allowed for multiple production runs without the user being exposed to radiation fields. The system was used to support clinical trials of [(18)F]fallypride, a neuroimaging radiopharmaceutical under IND Application #109,880. PMID:23135409

  1. Radiation Dosimetry and Biodistribution of the Translocator Protein Radiotracer [11C]DAA1106 Determined with PET/CT in Healthy Human Volunteers

    PubMed Central

    Brody, Arthur L.; Okita, Kyoji; Shieh, Jennifer; Liang, Lidia; Hubert, Robert; Mamoun, Michael; Farahi, Judah; Mandelkern, Mark A.

    2014-01-01

    Introduction When microglia become activated (an integral part of neuroinflammation), cellular morphology changes and expression of translocator protein (TSPO) 18 kDa is increased. Over the past several years, [11C]DAA1106 has emerged as a reliable radiotracer for labeling TSPO with high affinity during positron emission tomography (PET) scanning. While [11C]DAA1106 PET scanning has been used in several research studies, a radiation dosimetry study of this radiotracer in humans has not yet been published. Methods Twelve healthy participants underwent full body dynamic [11C]DAA1106 PET scanning, with 8 sequential whole body scans (approximately 12 bed positions each), following a single injection. Regions of interest were drawn manually and time activity curves (TACs) were obtained for 15 organs. OLINDA/EXM 1.1 was used to compute radiation absorbed doses to the target organs, as well as effective dose (ED) and effective dose equivalent (EDE). Results The ED and EDE were 4.06 ± 0.58 μSv/MBq and 5.89 ± 0.83 μSv/MBq, respectively. The highest absorbed doses were to the heart wall, kidney, liver, pancreas, and spleen. TACs revealed that peak dose rates are during the first scan (at 6 min) for all organs other than the urinary bladder wall, which had its peak dose rate during the fourth scan (at 30 min). Conclusions The recently developed radiotracer [11C]DAA1106 has its EDE and target-organ absorbed dose such that, for a single administration, its radiation dosimetry is well within the U.S. FDA guidelines for basic research studies in adults. This dose level implies that the dosimetry for multiple [11C]DAA1106 scans within a given year also falls within FDA guidelines, and this favorable property makes this radiotracer suitable for examining microglial activation repeatedly over time, which may in the future be useful for longitudinal tracking of disease progression and monitoring of therapy response in conditions marked by neuroinflammation (e.g., head trauma and

  2. Energy efficient engine: Preliminary design and integration studies

    NASA Technical Reports Server (NTRS)

    Johnston, R. P.; Hirschkron, R.; Koch, C. C.; Neitzel, R. E.; Vinson, P. W.

    1978-01-01

    Parametric design and mission evaluations of advanced turbofan configurations were conducted for future transport aircraft application. Economics, environmental suitability and fuel efficiency were investigated and compared with goals set by NASA. Of the candidate engines which included mixed- and separate-flow, direct-drive and geared configurations, an advanced mixed-flow direct-drive configuration was selected for further design and evaluation. All goals were judged to have been met except the acoustic goal. Also conducted was a performance risk analysis and a preliminary aerodynamic design of the 10 stage 23:1 pressure ratio compressor used in the study engines.

  3. Synthesis of carbon-11, fluorine-18, and nitrogen-13 labeled radiotracers for biomedical applications

    SciTech Connect

    Fowler, J.S.; Wolf, A.P.

    1981-01-01

    A number of reviews, many of them recent, have appeared on various aspects of /sup 11/C, /sup 18/F and /sup 13/N-labeled radiotracers. This monograph treats the topic principally from the standpoint of synthetic organic chemistry while keeping in perspective the necessity of integrating the organic chemistry with the design and ultimate application of the radiotracer. Where possible, recent examples from the literature of organic synthesis are introduced to suggest potentially new routes which may be applied to problems in labeling organic molecules with the short-lived positron emitters, carbon-11, fluorine-18, and nitrogen-13. The literature survey of carbon-11, fluorine-18 and nitrogen-13 labeled compounds presented are of particular value to scientists working in this field. Two appendices are also included to provide supplementary general references. A subject index concludes this volume.

  4. (68) Ga-labeled Ciprofloxacin Conjugates as Radiotracers for Targeting Bacterial Infection.

    PubMed

    Satpati, Drishty; Arjun, Chanda; Krishnamohan, Repaka; Samuel, Grace; Banerjee, Sharmila

    2016-05-01

    With an aim of developing a bacteria-specific molecular imaging agent, ciprofloxacin has been modified with a propylamine spacer and linked to two common bifunctional chelators, p-SCN-Bz-DOTA and p-SCN-Bz-NOTA. The two ciprofloxacin conjugates, CP-PA-SCN-Bz-DOTA (1) and CP-PA-SCN-Bz-NOTA (2), were radiolabeled with (68)Ga in >90% radiochemical yield and were moderately stable in vitro for 4 h. The efficacy of (68)Ga-1 and (68)Ga-2 has been investigated in vitro in Staphylococcus aureus cells where bacterial binding of the radiotracers (0.9-1.0% for (68)Ga-1 and 1.6-2.3% for (68)Ga-2) could not be blocked in the presence of excess amount of unlabeled ciprofloxacin. However, uptake of radiotracers in live bacterial cells was significantly higher (p < 0.01) than that in non-viable bacterial cells. Bacterial infection targeting efficacy of (68)Ga-1 and (68)Ga-2 was tested in vivo in rats where the infected muscle-to-inflamed muscle ((68)Ga-1: 2 ± 0.2, (68)Ga-2: 3 ± 0.5) and infected muscle-to-normal muscle ratios ((68)Ga-1: 3 ± 0.4, (68)Ga-2: 6.6 ± 0.8) were found to improve at 120 min p.i. Fast blood clearance and renal excretion was observed for both the radiotracers. The two (68)Ga-labeled infection targeting radiotracers could discriminate between bacterial infection and inflammation in vivo and are worthy of further detailed investigation as infection imaging agents at the clinical level. PMID:26647765

  5. Residence time distribution measurements in a pilot-scale poison tank using radiotracer technique.

    PubMed

    Pant, H J; Goswami, Sunil; Samantray, J S; Sharma, V K; Maheshwari, N K

    2015-09-01

    Various types of systems are used to control the reactivity and shutting down of a nuclear reactor during emergency and routine shutdown operations. Injection of boron solution (borated water) into the core of a reactor is one of the commonly used methods during emergency operation. A pilot-scale poison tank was designed and fabricated to simulate injection of boron poison into the core of a reactor along with coolant water. In order to design a full-scale poison tank, it was desired to characterize flow of liquid from the tank. Residence time distribution (RTD) measurement and analysis was adopted to characterize the flow dynamics. Radiotracer technique was applied to measure RTD of aqueous phase in the tank using Bromine-82 as a radiotracer. RTD measurements were carried out with two different modes of operation of the tank and at different flow rates. In Mode-1, the radiotracer was instantaneously injected at the inlet and monitored at the outlet, whereas in Mode-2, the tank was filled with radiotracer and its concentration was measured at the outlet. From the measured RTD curves, mean residence times (MRTs), dead volume and fraction of liquid pumped in with time were determined. The treated RTD curves were modeled using suitable mathematical models. An axial dispersion model with high degree of backmixing was found suitable to describe flow when operated in Mode-1, whereas a tanks-in-series model with backmixing was found suitable to describe flow of the poison in the tank when operated in Mode-2. The results were utilized to scale-up and design a full-scale poison tank for a nuclear reactor. PMID:26057343

  6. Cerenkov Luminescence Endoscopy: Improved Molecular Sensitivity with β−-Emitting Radiotracers

    PubMed Central

    Carpenter, Colin M.; Ma, Xiaowei; Liu, Hongguang; Sun, Conroy; Pratx, Guillem; Wang, Jing; Gambhir, Sanjiv S.; Xing, Lei; Cheng, Zhen

    2015-01-01

    Cerenkov luminescence endoscopy (CLE) is an optical technique that captures the Cerenkov photons emitted from highly energetic moving charged particles (β+ or β−) and can be used to monitor the distribution of many clinically available radioactive probes. A main limitation of CLE is its limited sensitivity to small concentrations of radiotracer, especially when used with a light guide. We investigated the improvement in the sensitivity of CLE brought about by using a β− radiotracer that improved Cerenkov signal due to both higher β-particle energy and lower γ noise in the imaging optics because of the lack of positron annihilation. Methods The signal-to-noise ratio (SNR) of 90Y was compared with that of 18F in both phantoms and small-animal tumor models. Sensitivity and noise characteristics were demonstrated using vials of activity both at the surface and beneath 1 cm of tissue. Rodent U87MG glioma xenograft models were imaged with radiotracers bound to arginine-glycine-aspartate (RGD) peptides to determine the SNR. Results γ noise from 18F was demonstrated by both an observed blurring across the field of view and a more pronounced fall-off with distance. A decreased γ background and increased energy of the β particles resulted in a 207-fold improvement in the sensitivity of 90Y compared with 18F in phantoms. 90Y-bound RGD peptide produced a higher tumor-to-background SNR than 18F in a mouse model. Conclusion The use of 90Y for Cerenkov endoscopic imaging enabled superior results compared with an 18F radiotracer. PMID:25300598

  7. Positron detection in silica monoliths for miniaturised quality control of PET radiotracers.

    PubMed

    Tarn, Mark D; Maneuski, Dzmitry; Alexander, Richard; Brown, Nathaniel J; O'Shea, Val; Pimlott, Sally L; Pamme, Nicole; Archibald, Stephen J

    2016-06-01

    We demonstrate the use of the miniaturised Medipix positron sensor for detection of the clinical PET radiotracer, [(68)Ga]gallium-citrate, on a silica-based monolith, towards microfluidic quality control. The system achieved a far superior signal-to-noise ratio compared to conventional sodium iodide-based radio-HPLC detection and allowed real-time visualisation of positrons in the monolith. PMID:27029282

  8. A system to obtain radiotracer uptake data simultaneously with NMR spectra in a high field magnet

    SciTech Connect

    Buchanan, M.; Marsden, P.K.; Garlick, P.B.; Mielke, C.H.

    1996-06-01

    Radiotracer techniques and nuclear magnetic resonance (NMR) spectroscopy are two complementary methods that are widely used to investigate cardiac metabolism. The authors have now developed a novel gamma photon detector system that will operate within a wide-bore, 9.4 T magnet. With this detector in position, it is possible to acquire radiotracer uptake data while simultaneously collecting NMR spectra. The advantages of this new system are firstly, that it enables correlations between radiotracer and NMR data to be made on individual rat hearts, and secondly that it allows the number of experiments required to obtain results of statistical significance to be greatly decreased. The extension of the system, to one in which positron emission tomography (PET) and magnetic resonance imaging (MRI) data are acquired simultaneously, clearly has enormous clinical potential. The detector consists of a NaI(Tl) scintillation crystal coupled to a magnetic field-insensitive photomultiplier tube by a 72.5 cm long, acrylic light pipe. This detector configuration satisfies the two, conflicting requirements of the crystal being near the sample, and thus in a high magnetic field, and the PMT being in a low magnetic field and thus far from the sample. In this paper the authors present the technical specifications of their new system together with what they believe are the first examples of simultaneously acquired NMR spectra and {sup 18}F-fluorodeoxyglucose ({sup 18}FDG) uptake data, obtained from isolated, perfused rat hearts.

  9. Comparative study of spray booth filter system efficiency

    SciTech Connect

    Darvin, C.H.; Cox, L.S.; Smith, D.

    1997-12-31

    During recent years, greater emphasis has been placed on the control of particulate emissions from painting operations. This has gained importance as more is learned about the potential release of toxic metals to the atmosphere from painting operations. This has led to queries about the efficiency of various painting arrestor systems to reduce particulate discharges to the atmosphere. Even more important is the capability of the arrestor systems to control PM-10 emissions. In 1995, the USEPA initiated a study to evaluate various dry paint overspray arrestor systems. This study was designed to evaluate, not only the total emissions control capability of the arrestor, but also the PM-10 control capability of the various system designs. Paint overspray arrestor systems using five different filtration concepts and/or materials were selected. They include systems constructed of fiberglass, paper, styrofoam, and cardboard. These systems used filtration techniques incorporating the following filtration phenomena and designs: cyclone, baffle, bag systems, and mesh systems. The testing used an optical particle counting procedure to determine the concentration of particles of a given size fraction to penetrate a test arrestor system. The results of the testing indicated that there are significant differences in the efficiency of the tested system designs to capture and retain PM-10. This paper summarizes the results of the research conducted to determine the capability of the arrestor systems to capture particulate of particle sizes down to approximately 1 {micro}m in surface diameter.

  10. Energy efficient engine preliminary design and integration study

    NASA Technical Reports Server (NTRS)

    Gray, D. E.

    1978-01-01

    The technology and configurational requirements of an all new 1990's energy efficient turbofan engine having a twin spool arrangement with a directly coupled fan and low-pressure turbine, a mixed exhaust nacelle, and a high 38.6:1 overall pressure ratio were studied. Major advanced technology design features required to provide the overall benefits were a high pressure ratio compression system, a thermally actuated advanced clearance control system, lightweight shroudless fan blades, a low maintenance cost one-stage high pressure turbine, a short efficient mixer and structurally integrated engine and nacelle. A conceptual design analysis was followed by integration and performance analyses of geared and direct-drive fan engines with separate or mixed exhaust nacelles to refine previously designed engine cycles. Preliminary design and more detailed engine-aircraft integration analysis were then conducted on the more promising configurations. Engine and aircraft sizing, fuel burned, and airframe noise studies on projected 1990's domestic and international aircraft produced sufficient definition of configurational and advanced technology requirements to allow immediate initiation of component technology development.

  11. Efficient Project Delivery Using Lean Principles - An Indian Case Study

    NASA Astrophysics Data System (ADS)

    Kovvuri, P. Ramachandra Reddy; Sawhney, Anil; Ahuja, Ritu; Sreekumar, Aiswarya

    2016-03-01

    Construction industry in India is growing at a rapid pace. Along with this growth, the industry is facing numerous challenges that are making delivery of projects inefficient. Experts believe that capacity constraints in the industry need to be addressed immediately. Government has recommended `introduction of efficient technologies and modern management techniques' to increase the productivity of the industry. In this context, lean principles can act as a lever to make project delivery more efficient and provide the much needed impetus to the Indian construction sector. Around the globe lean principles are showing positive results on the projects. Project teams are reporting improvements in construction time, cost and quality along with softer benefits of enhanced collaboration, coordination and trust in project teams. Can adoption of lean principles provide similar benefits in the Indian construction sector? This research was conducted to answer this question. Using an action research approach a key lean construction tool called Last Planner System (LPS) was tested on a large Indian construction project. The work described in this work investigates the improvements achieved in project delivery by adopting LPS in Indian construction sector. Comparison in pre- and post-implementation data demonstrates increase in the certainty of work-flow and improves schedule compliance. This is measured through a simple LPS metric called percent plan complete. Explicit improvements in schedule performance are seen during 8 week LPS implementation along with implicit improvements in coordination, collaboration and trust in the project team. This work reports the findings of LPS implementation on the case study project outlining the barriers and drivers to adoption, strategies needed to ensure successful implementation and roadmap for implementation. Based on the findings the authors envision that lean construction can make project delivery more efficient in India.

  12. Basic studies of 3-V high efficiency cell components

    NASA Astrophysics Data System (ADS)

    Lundstrom, M. S.; Melloch, M. R.; Pierret, R. F.; Carpenter, M. S.; Chuang, H. L.; Keshavarzi, A.; Klausmeier-Brown, M. E.; Lush, G. B.; Morgan, J. M.; Stellwag, T. B.

    1990-07-01

    This project's objective is to improve our fundamental understanding of the generation, recombination, and transport of carriers within III-V homo- and heterostructures. The research consists of fabricating and characterizing solar cell building blocks such as junctions and heterojunctions as well as basic measurements of material parameters. A significant effort is also being directed at characterizing loss mechanisms in high-quality, III-V solar cells fabricated in industrial research laboratories throughout the United States. The project's goal is to use our understanding of the device physics of high-efficiency cell components to maximize cell efficiency. A related goal is the demonstration of new cell structures fabricated by molecular beam epitaxy (MBE). The development of measurement techniques and characterization methodologies is also a project objective. We expect that the insight into III-V device physics occurring during the course of this work will help to identify paths toward higher efficiency III-V cells. This report describes our progress during the fourth year of the project. The past year's efforts centered on completing studies of heavy doping effects in p(sup +)-GaAs and assessing the importance of similar effects in n(sup +)-GaAs, and at continuing research on characterizing, controlling, and passivating perimeter recombination currents. We also initiated work to identify the dominant loss mechanism in Al(sub 0.2)Ga(sub 0.8) As solar cells and brought on-line a new MBE growth facility and demonstrated the high-quality of the films by fabricating, with assistance from Spire Corporation, 23.8 percent 1-sun solar cells.

  13. Synthesis and Biological Evaluation of Thiophene-Based Cannabinoid Receptor Type 2 Radiotracers for PET Imaging

    PubMed Central

    Haider, Ahmed; Müller Herde, Adrienne; Slavik, Roger; Weber, Markus; Mugnaini, Claudia; Ligresti, Alessia; Schibli, Roger; Mu, Linjing; Mensah Ametamey, Simon

    2016-01-01

    Over the past two decades, our understanding of the endocannabinoid system has greatly improved due to the wealth of results obtained from exploratory studies. Currently, two cannabinoid receptor subtypes have been well-characterized. The cannabinoid receptor type 1 (CB1) is widely expressed in the central nervous system, while the levels of the cannabinoid receptor type 2 (CB2) in the brain and spinal cord of healthy individuals are relatively low. However, recent studies demonstrated a CB2 upregulation on activated microglia upon neuroinflammation, an indicator of neurodegeneration. Our research group aims to develop a suitable positron emission tomography (PET) tracer to visualize the CB2 receptor in patients suffering from neurodegenerative diseases. Herein we report two novel thiophene-based 11C-labeled PET ligands designated [11C]AAT-015 and [11C]AAT-778. The reference compounds were synthesized using Gewald reaction conditions to obtain the aminothiophene intermediates, followed by amide formation. Saponification of the esters provided their corresponding precursors. Binding affinity studies revealed Ki-values of 3.3 ± 0.5 nM (CB2) and 1.0 ± 0.2 μM (CB1) for AAT-015. AAT-778 showed similar Ki-values of 4.3 ± 0.7 nM (CB2) and 1.1 ± 0.1 μM (CB1). Radiosynthesis was carried out under basic conditions using [11C]iodomethane as methylating agent. After semi-preparative HPLC purification both radiolabeled compounds were obtained in 99% radiochemical purity and the radiochemical yields ranged from 12 to 37%. Specific activity was between 96 and 449 GBq/μmol for both tracers. In order to demonstrate CB2 specificity of [11C]AAT-015 and [11C]AAT-778, we carried out autoradiography studies using CB2-positive mouse/rat spleen tissues. The obtained results revealed unspecific binding in spleen tissue that was not blocked by an excess of CB2-specific ligand GW402833. For in vivo analysis, [11C]AAT-015 was administered to healthy rats via tail-vein injection

  14. Online crowdsourcing for efficient rating of speech: A validation study

    PubMed Central

    Byun, Tara McAllister; Halpin, Peter F.; Szeredi, Daniel

    2015-01-01

    Blinded listener ratings are essential for valid assessment of interventions for speech disorders, but collecting these ratings can be time-intensive and costly. This study evaluated the validity of speech ratings obtained through online crowdsourcing, a potentially more efficient approach. 100 words from children with /r/ misarticulation were electronically presented for binary rating by 35 phonetically trained listeners and 205 naïve listeners recruited through the Amazon Mechanical Turk (AMT) crowdsourcing platform. Bootstrapping was used to compare different-sized samples of AMT listeners against a “gold standard” (mode across all trained listeners) and an “industry standard” (mode across bootstrapped samples of 3 trained listeners). There was strong overall agreement between trained and AMT listeners. The “industry standard” level of performance was matched by bootstrapped samples with n = 9 AMT listeners. These results support the hypothesis that valid ratings of speech data can be obtained in an efficient manner through AMT. Researchers in communication disorders could benefit from increased awareness of this method. PMID:25578293

  15. (Energy efficiency improvement studies for Costa Rica and Guatemala)

    SciTech Connect

    Waddle, D.B.

    1990-05-30

    I travelled to San Jose, Cost Rica, on May 20, 1990 to report on the progress of the Integrated Power Sector Efficiency Analysis Project to the Instituto Costarrincense de Electricidad, and to USAID/San Jose. I also discussed the progress and plans for the CONELECTRICAS Small Hydroelectric Project supported by ORNL through the Renewable Energy Applications and Training Project. Both projects are proceeding on schedule. ORNL will complete further supply side analysis after comments are submitted by ICE, with respect to the information provided on this visit. The CONELECTRICAS project will require further ORNL input to assist in optimization of equipment selection and to perform the required financial and economic cost analyses. I travelled to Guatemala City on May 22, 1990. I met with Instituto Nacional de Electricacion (INDE) to discuss the findings and recommendations of the Electric Power Utility Efficiency Improvement Study undertaken in February, 1990. I also met with Mario Funes to discuss future ORNL assistance to ROCAP in support of the CARES project as well as other ROCAP energy initiatives.

  16. Experimental study on mixing efficiency in water supply rectangular tanks

    NASA Astrophysics Data System (ADS)

    Bateman, A.; Medina, V.; Mujal, A.

    2009-04-01

    Phenomenon of mixing in drinking water storage tanks and reservoirs has a direct effect on the quality of water. Creation of poor mixing zones and volume stratification can have negative effects in public health. The design of a storage tank must consider the conditions of the inlet and outlets, and also their orientation (vertical or horizontal) to prevent the formation of these zones. Experiments done in a reduced scaled-model with a rectangular base and three different inlets (two waterfalls and a pipe inlet) had the objective to decide which of these inlets achieved the best mixing efficiency. Four situations were considered while three entrances, two unsteady: filling and drawing, and two steady with different outlets. Moreover the effects of columns that support the roof of the tank were studied by running the three entrances with and without columns in the four situations. Neglecting the viscous scale effects, the time taken to mix the volume stored depends on the distance between the inlet and the opposite wall as though as its orientation. Taking into account the whole tank columns have a negative effect on mixing efficiency although they divide the flux and create local zones of turbulence around them, increasing local mixing. Using a digital treating image technique the results are found in a quantitative way.

  17. In vivo imaging of reactive oxygen species in mouse brain by using [3H]hydromethidine as a potential radical trapping radiotracer.

    PubMed

    Abe, Kohji; Takai, Nozomi; Fukumoto, Kazumi; Imamoto, Natsumi; Tonomura, Misato; Ito, Miwa; Kanegawa, Naoki; Sakai, Katsunori; Morimoto, Kenji; Todoroki, Kenichiro; Inoue, Osamu

    2014-12-01

    To assess reactive oxygen species (ROS) production by detecting the fluorescent oxidation product, hydroethidine has been used extensively. The present study was undertaken to evaluate the potential of the hydroethidine derivative as a radiotracer to measure in vivo brain ROS production. [(3)H]-labeled N-methyl-2,3-diamino-6-phenyl-dihydrophenanthridine ([(3)H]Hydromethidine) was synthesized, and evaluated using in vitro radical-induced oxidization and in vivo brain ROS production model. In vitro studies have indicated that [(3)H]Hydromethidine is converted to oxidized products by a superoxide radical (O(2)(•)-) and a hydroxyl radical (OH(•)-) but not hydrogen peroxide (H(2)O(2)). In vivo whole-body distribution study showed that [(3)H]Hydromethidine rapidly penetrated the brain and then was washed out in normal mice. Microinjection of sodium nitroprusside (SNP) into the brain was performed to produce ROS such as OH(•)- via Fenton reaction. A significant accumulation of radioactivity immediately after [(3)H]Hydromethidine injection was seen in the side of the brain treated with SNP (5 and 20 nmol) compared with that in the contralateral side. These results indicated that [(3)H]Hydromethidine freely penetrated into the brain where it was rapidly converted to oxidized forms, which were trapped there in response to the production of ROS. Thus, [(3)H]Hydromethidine should be useful as a radical trapping radiotracer in the brain. PMID:25227606

  18. Suitable scheme study of Chinese Building Energy Efficiency CDM Projects

    NASA Astrophysics Data System (ADS)

    Huang, Beijia; Yang, Haizhen; Wang, Shaoping; Wang, Feng

    2010-11-01

    China has great potential to develop Building Energy Efficiency Clean Development Mechanism (BEE CDM) projects, although have many challenges. Our results show that large-scale public buildings and urban residential buildings have relatively high BEE CDM potential, when comparing their characteristics to the CDM project requirements. The building enclosure, illumination energy conservation, air condition energy saving, solar thermal, and solar photovoltaic technology have relatively high application potential while considering the energy saving potential and marginal emission reduction cost. Case study of large-scale buildings shows that technology integration of building enclosure, illumination energy conservation, air condition energy saving, solar thermal can reduce required building number to 130 in order to meet the 1×105 tCO2 e/a reduction criteria. Some suggestions are also given in this paper.

  19. Assimilation efficiencies of chemical contaminants in aquatic invertebrates: A synthesis

    SciTech Connect

    Wang, W.X.; Fisher, N.S.

    1999-09-01

    Assimilation efficiencies of contaminants from ingested food are critical for understanding chemical accumulation and trophic transfer in aquatic invertebrates. Assimilation efficiency is a first-order physiological parameter that can be used to systematically compare the bioavailability of different contaminants from different foods. The various techniques used to measure contaminant assimilation efficiencies are reviewed. Pulse-chase feeding techniques and the application of gamma-emitting radiotracers have been invaluable in measuring metal assimilation efficiencies in aquatic animals. Uniform radiolabeling of food is required to measure assimilation, but this can be difficult when sediments are the food source. Biological factors that influence contaminant assimilation include food quantity and quality, partitioning of contaminants in the food particles, and digestive physiology of the animals. Other factors influencing assimilation include the behavior of the chemical within the animal's gut and its associations with different geochemical fractions of food particles. Assimilation efficiency is a critical parameter to determine (and to make predictions of) bioaccumulation of chemicals from dietary exposure. Robust estimates of assimilation efficiency coupled with estimates of aqueous uptake can be used to determine the relative importance of aqueous and dietary exposures. For bioaccumulation of metals from sediments, additional studies are required to test whether metals bound to the acid-volatile sulfide fraction of sediments can be available to benthic deposit-feeding inverterbrates. Most assimilation efficiency studies have focused on chemical transfer in organisms at the bottom of the food chain; additional studies are required to examine chemical transfer at higher trophic levels.

  20. Development of a system for real-time measurements of metabolite transport in plants using short-lived positron-emitting radiotracers

    NASA Astrophysics Data System (ADS)

    Kiser, Matthew R.

    be introduced to plants as biologically active molecules such as 11CO2, N13O-3, 18F--[H2O], and H152O . Plants for these studies are grown in controlled-environment chambers at the Phytotron. The chambers offer an array of control for temperature, humidity, atmospheric CO2 concentration, and light intensity. Additionally, the Phytotron houses one large reach-in growth chamber that is dedicated to this project for radioisotope labeling measurements. There are several important properties of short-lived positron-emitting radio-tracers that make them well suited for use in investigating metabolite transport in plants. First, because the molecular mass of a radioisotope-tagged compound is only minutely different from the corresponding stable compound, radiotracer substances should be metabolized and transported in plants the same as their non-radioactive counterparts. Second, because the relatively high energy gamma rays emitted from electron-positron annihilation are attenuated very little by plant tissue, the real-time distribution of a radiotracer can be measured in vivo in plants. Finally, the short radioactive half-lives of these isotopes allow for repeat measurements on the same plant in a short period of time. For example, in studies of short-term environmental changes on plant metabolite dynamics, a single plant can be labeled multiple times to measure its responses to different, environmental conditions. Also, different short-lived radiotracers can be applied to the same plant over a short period of time to investigate the transport and allocation of various metabolites. This newly developed system provides the capabilities for production of 11CO2 at TUNL, transfer of the 11CO 2 gas from the target area at TUNL to a radiation-shielded cryogenic trap at the Phytotron, labeling of photoassimilates with 11C, and in vivo gamma-ray detection for real-time measurements of the radiotracer distribution in small plants. The experimental techniques and instrumentation

  1. Applications of Beta Particle Detection for Synthesis and Usage of Radiotracers Developed for Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Dooraghi, Alex Abreu

    Positron Emission Tomography (PET) is a noninvasive molecular imaging tool that requires the use of a radioactive compound or radiotracer which targets a molecular pathway of interest. We have developed and employed three beta particle radiation detection systems to advance PET. Specifically, the goals of these systems are to: 1. Automate dispensing of solutions containing a positron emitting isotope. 2. Monitor radioactivity on-chip during synthesis of a positron emitting radiotracer. 3. Assay cellular uptake on-chip of a positron emitting radiotracer. Automated protocols for measuring and dispensing solutions containing radioisotopes are essential not only for providing an optimum environment for radiation workers, but also to ensure a quantitatively accurate workflow. For the first project, we describe the development and performance of a system for automated radioactivity distribution of beta particle emitting radioisotopes such as fluorine-18 (F-18). Key to the system is a radiation detector in-line with a peristaltic pump. The system demonstrates volume accuracy within 5 % for volumes of 20 muL or greater. When considering volumes of 20 muL or greater, delivered radioactivity is in agreement with the requested radioactivity as measured with the dose calibrator. The integration of the detector and pump leads to a flexible system that can accurately dispense solutions containing F-18 in radioactivity concentrations directly produced from a cyclotron (~ 0.1-1 mCi/muL), to low activity concentrations intended for preclinical mouse scans (~ 1-10 muCi/muL), and anywhere in between. Electrowetting on dielectric (EWOD) is an attractive microfluidic platform for batch synthesis of PET radiotracers. Visualization of radioisotopes on-chip is critical for synthesis optimization and technological development. For the second project, we describe the development and performance of a Cerenkov/real-time imaging system for PET radiotracer synthesis on EWOD. We also investigate

  2. A theoretical study of the efficiency of the general circulation

    NASA Technical Reports Server (NTRS)

    Schulman, L. L.

    1977-01-01

    The paper examines the problem of explaining the atmospheric efficiency, or equivalently, the rate of generation of available potential energy (APE) by diabatic heating. Attention is focused on determining the maximum possible rate of generation of APE and its accompanying temperature field, which does not require a knowledge of the atmospheric motions leading to temperature distribution. Qualitative and quantitative results indicate that the atmosphere may be operating within approximately a factor of 2 of its maximum efficiency. The general circulation may be operating at nearly its maximum efficiency.

  3. Evaluation of [11C]metergoline as a PET radiotracer for 5HTR in nonhuman primates

    SciTech Connect

    Hooker, J.M.; Hooker, J.M.; Kim, S.W.; Reibel, A.T.; Alexoff, D.; Xu, Y.; Shea, C.

    2010-04-20

    Metergoline, a serotonin receptor antagonist, was labeled with carbon-11 in order to evaluate its pharmacokinetics and distribution in non-human primates using positron emission tomography. [{sup 11}C]Metergoline had moderate brain uptake and exhibited heterogeneous specific binding, which was blocked by pretreatment with metergoline and altanserin throughout the cortex. Non-specific binding and insensitivity to changes in synaptic serotonin limit its potential as a PET radiotracer. However, the characterization of [{sup 11}C]metergoline pharmacokinetics and binding in the brain and peripheral organs using PET improves our understanding of metergoline drug pharmacology.

  4. Development of radiotracers for oncology – the interface with pharmacology

    PubMed Central

    Sharma, Rohini; Aboagye, Eric

    2011-01-01

    There is an increasing role for positron emission tomography (PET) in oncology, particularly as a component of early phase clinical trials. As a non-invasive functional imaging modality, PET can be used to assess both pharmacokinetics and pharmacodynamics of novel therapeutics by utilizing radiolabelled compounds. These studies can provide crucial information early in the drug development process that may influence the further development of novel therapeutics. PET imaging probes can also be used as early biomarkers of clinical response and to predict clinical outcome prior to the administration of therapeutic agents. We discuss the role of PET imaging particularly as applied to phase 0 studies and discuss the regulations involved in the development and synthesis of novel radioligands. The review also discusses currently available tracers and their role in the assessment of pharmacokinetics and pharmacodynamics as applied to oncology. LINKED ARTICLES This article is part of a themed section on Imaging. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2011.163.issue-8BJP has previously published an Imaging in Pharmacology themed section, edited by A Davenport and C Daly. To view this section visit http://dx.doi.org/10.1111/bph.2010.159.issue-4 PMID:21175573

  5. Radiotracers application to determine laminar flow at a pipe

    SciTech Connect

    Ramirez-Garcia, F.P.; Cortes-Islas, E. )

    1988-06-01

    To measure gas flow in a gas venting line in an Oil Refinery the method of two points and iodine-131 labelled methyl iodide molecule was used. Forty-four complete sets of data were obtained corresponding to measurements performed in the gas venting line. Conditions of laminar and semi-turbulent flow were found. In the case of laminar flow measurement it was necessary to construct an injection equipment, consisting of a tubing with five slits to simultaneously inject the tracer into the gas stream at different points. For the laminar flow is obtained the transversal distribution of fluid velocities. The mean flow of the gas transported by the line under study was determined, and its standard deviation was calculated.

  6. Radiotracer computer modeling evidence that phospho-base methylation is the main route of choline synthesis in tobacco

    SciTech Connect

    McNeil, S.D.; Nuccio, M.L.; Rhodes, D.; Shachar-Hill, Y.; Hanson, A.D.

    2000-05-01

    Among flowering plants, the synthesis of choline (Cho) from ethanolamine (EA) can potentially occur via three parallel, interconnected pathways involving methylation of free bases, phospho-bases, or phosphatidyl-bases. The authors investigated which pathways operate in tobacco (Nicotiana tabacum L.) because previous work has shown that the endogenous Cho supply limits accumulation of glycine betaine in transgenic tobacco plants engineered to convert Cho to glycine betaine. The kinetics of metabolite labeling were monitored in leaf discs supplied with [{sup 33}P]phospho-EA,[{sup 33}P]phospho-monomethylethanolamine, or [{sup 14}C]formate, and the data were subjected to computer modeling. Because partial hydrolysis of phospho-bases occurred in the apoplast, modeling of phospho-base metabolism required consideration of the re-entry of [{sup 33}P]phosphate into the network. Modeling of [{sup 14}C]formate metabolism required consideration of the labeling of the EA and methyl moieties of Cho. Results supported the following conclusions: (a) The first methylation step occurs solely at the phospho-base level; (b) the second and third methylations occur mainly (83%--92% and 65%--85%, respectively) at the phospho-base level, with the remainder occurring at the phosphatidyl-base level; and (c) free Cho originates predominantly from phosphatidylcholine rather than from phospho-Cho. This study illustrates how computer modeling of radiotracer data, in conjunction with information on chemical pool sizes, can provide a coherent, quantitative picture of fluxes within a complex metabolic network.

  7. Optimizing tumor targeting of the lipophilic EGFR-binding radiotracer SKI 243 using a liposomal nanoparticle delivery system.

    PubMed

    Medina, Oula Penate; Pillarsetty, Nagavarakishore; Glekas, Athanasios; Punzalan, Blesida; Longo, Valerie; Gönen, Mithat; Zanzonico, Pat; Smith-Jones, Peter; Larson, Steven M

    2011-02-10

    Positron emission tomography (PET) of epidermal growth factor receptor (EGFR) kinase-specific radiolabeled tracers could provide a means for non-invasively characterizing EGFR expression and signaling activity in patients' tumors before, during, and after therapy with EGFR inhibitors. Towards this goal, our group has developed PET tracers which irreversibly bind to EGFR. However, tumor uptake is relatively low because of both the lipophilicity of such tracers (e.g. the morpholino-[124I]-IPQA [SKI 212243]), with octanol-to-water partition coefficients of up to 4, and a short dwell time in the blood and significant hepatobiliary clearance and intestinal reuptake. Liposomal nanoparticle delivery systems may favorably alter the pharmacokinetic profile and improve tumor targeting of highly lipophilic but otherwise promising cancer imaging tracers, such as the EGFR inhibitor SKI 243. SKI 243 is therefore an interesting model molecule for incorporation into lipid-based nanoparticles, as it would not only improve their solubility but also increase the circulation time, availability and, potentially, targeting of tumors. In the current study, we compared the pharmacokinetics and tumor targeting of the bare EGFR kinase-targeting radiotracer SKI 212243 (SKI 243) with that of the same tracer embedded in liposomes. SKI 243 and liposomal SKI 243 are both taken up by tumor xenografts but liposomal SKI 243 remained in the blood longer and consequently exhibited a 3- to 6-fold increase in uptake in the tumor among several other organs. PMID:21047536

  8. Optimizing tumor targeting of the lipophilic EGFR-binding radiotracer SKI243 using a liposomal nanoparticle delivery system

    PubMed Central

    Pillarsetty, Nagavarakishore; Glekas, Athanasios; Punzalan, Blesida; Longo, Valerie; Gönen, Mithat; Zanzonico, Pat; Smith-Jones, Peter

    2015-01-01

    Positron emission tomography (PET) of epidermal growth factor receptor (EGFR) kinase-specific radiolabeled tracers could provide a means for non-invasively characterizing EGFR expression and signaling activity in patients' tumors before, during, and after therapy with EGFR inhibitors. Towards this goal, our group has developed PET tracers which irreversibly bind to EGFR. However, tumor uptake is relatively low because of both the lipophilicity of such tracers (e.g. the morpholino-[124I]-IPQA [SKI212243]), with octanol-to-water partition coefficients of up to 4, and a short dwell time in the blood and significant hepatobiliary clearance and intestinal reuptake. Liposomal nanoparticle delivery systems may favorably alter the pharmacokinetic profile and improve tumor targeting of highly lipophilic but otherwise promising cancer imaging tracers, such as the EGFR inhibitor SKI243. SKI243 is therefore an interesting model molecule for incorporation into lipid-based nanoparticles, as it would not only improve their solubility but also increase the circulation time, availability and, potentially, targeting of tumors. In the current study, we compared the pharmacokinetics and tumor targeting of the bare EGFR kinase-targeting radiotracer SKI212243 (SKI243) with that of the same tracer embedded in liposomes. SKI243 and liposomal SKI243 are both taken up by tumor xenografts but liposomal SKI243 remained in the blood longer and consequently exhibited a 3- to 6-fold increase in uptake in the tumor among several other organs. PMID:21047536

  9. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G.

    1989-04-01

    One of the major goals of all compressor manufacturers is to build as efficient a compressor as possible. Over the last several years improvements to the design of screw compressors has made them efficiently competitive with other types of compressors, especially at large loads. The primary purpose of this research is to investigate four different methods of cooling a 250 horsepower compressor and determine their effects on the efficiency of the compressor. Two conventional methods, liquid injection and thermosyphon cooling, and two new methods, V-PLUS and Fresco oil injection, are investigated. The screw compressor used in the tests was a VRS-500 screw compressor made by the Vilter Manufacturing Corporation. 6 figs.

  10. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

  11. Pulmonary clearance of radiotracers after positive end-expiratory pressure or acute lung injury

    SciTech Connect

    Barrowcliffe, M.P.; Zanelli, G.D.; Jones, J.G.

    1989-01-01

    In anesthetized rabbits we measured clearance from lung to blood of eight aerosolized technetium-99m-labeled compounds: diethylenetriaminepentaacetate (99mTc-DTPA); cytochrome c; myoglobin; a myoglobin polymer; albumin; and anionic, cationic, and neutral dextrans of equivalent molecular size. We investigated the effect of applying positive end-expiratory pressure (PEEP) and, on a subsequent occasion, of injecting oleic acid intravenously to produce acute lung injury on the pulmonary clearance rate. Base-line clearance rates were monoexponential and varied with the molecular weights of the radiotracers. For each tracer the rate of clearance was increased a similar degree by either PEEP or oleic acid. However, with PEEP, clearance remained monoexponential, whereas after oleic acid, smaller molecular-weight radiotracers had multiexponential clearance curves. This suggests that after oleic acid the alveolar epithelium breaks down in a nonuniform fashion. We conclude that differentiation of the effect of PEEP from that of severe lung injury caused by oleic acid is not readily accomplished by either increasing the size of the tracer molecule or by varying the molecular charge.

  12. Study of High-Efficiency Motors Using Soft Magnetic Cores

    NASA Astrophysics Data System (ADS)

    Tokoi, Hirooki; Kawamata, Shoichi; Enomoto, Yuji

    We have been developed a small and highly efficient axial gap motor whose stator core is made of a soft magnetic core. First, the loss sensitivities to various motor design parameters were evaluated using magnetic field analysis. It was found that the pole number and core dimensions had low sensitivity (≤ 2.2dB) in terms of the total loss, which is the sum of the copper loss and the iron losses in the stator core and the rotor yoke respectively. From this, we concluded that to improve the motor efficiency, it is essential to reduce the iron loss in the rotor yoke and minimize other losses. With this in mind, a prototype axial gap motor is manufactured and tested. The motor has four poles and six slots. The motor is 123mm in diameter and the axial length is 47mm. The rotor has parallel magnetized magnets and a rotor yoke with magnetic steel sheets. The maximum measured motor efficiency is 93%. This value roughly agrees with the maximum calculated efficiency of 95%.

  13. Basic studies of 3-5 high efficiency cell components

    SciTech Connect

    Lundstrom, M.S.; Melloch, M.R.; Pierret, R.F.; Carpenter, M.S.; Chuang, H.L.; Dodd, P.E.; Keshavarzi, A.; Klausmeier-Brown, M.E.; Lush, G.B.; Stellwag, T.B. )

    1993-01-01

    This project's objective is to improve our understanding of the generation, recombination, and transport of carriers within III-V homo- and heterostructures. The research itself consists of fabricating and characterizing solar cell building blocks'' such as junctions and heterojunctions as well as basic measurements of material parameters. A significant effort is also being directed at characterizing loss mechanisms in high-quality, III-V solar cells fabricated in industrial research laboratories throughout the United States. The project's goal is to use our understanding of the device physics of high-efficiency cell components to maximize cell efficiency. A related goal is the demonstration of new cell structures fabricated by molecular beam epitaxy (MBE). The development of measurement techniques and characterization methodologies is also a project objective. This report describes our progress during the fifth and final year of the project. During the past five years, we've teamed a great deal about heavy doping effects in p[sup +] and n[sup +] GaAs and have explored their implications for solar cells. We have developed an understanding of the dominant recombination losses in present-day, high-efficiency cells. We've learned to appreciated the importance of recombination at the perimeter of the cell and have developed techniques for chemically passivating such edges. Finally, we've demonstrated that films grown by molecular beam epitaxy are suitable for high-efficiency cell research.

  14. An Efficient Method to Study Nondiffusive Motion of Brownian Particles

    NASA Astrophysics Data System (ADS)

    Lisý, Vladimír; Tóthová, Jana

    2016-02-01

    The experimental access to short timescales has pointed to the inadequacy of the standard Langevin theory of the Brownian motion (BM) in fluids. The hydrodynamic theory of the BM describes well the observed motion of the particles; however, the published approach should be improved in several points. In particular, it leads to incorrect correlation properties of the thermal noise driving the particles. In our contribution we present an efficient method, which is applicable to linear generalized Langevin equations describing the BM of particles with any kind of memory and apply it to interpret the experiments where nondiffusive BM of particles was observed. It is shown that the applicability of the method is much broader, allowing, among all, to obtain efficient solutions of various problems of anomalous BM.

  15. Efficiency study of oil cooling of a screw compressor

    SciTech Connect

    Tree, D.R.; McKellar, M.G. . Ray W. Herrick Labs.); Fresco, A. )

    1990-01-01

    One of the major goals of all compressor manufacturers is to design and build as efficient a compressor as possible. In a screw compressor it appears that the way the compressor is cooled can have an effect on the compressor's efficiency. This paper presents experimental data on three different screw compressor cooling methods: Liquid Refrigerant Injection Cooling System; Thermosyphon Cooling System; and Oil Injection System. All tests were conducted on a hot gas bypass system using refrigerant R-22. The data taken shows that the Oil Injection System is slightly better than the other two. These tests should be repeated with a higher oil flow rate and ammonia as the working fluid. 10 figs.

  16. Energy efficient engine preliminary design and integration studies

    NASA Technical Reports Server (NTRS)

    Johnston, R. P.; Hemsworth, M. C.

    1978-01-01

    The characteristics and systems benefits of an energy efficient engine (E3) suitable for use on advanced subsonic transport aircraft were determined. Relative to a current CF6-50C engine, the following benefits were estimated: 14.4% reduction in installed cruise specific fuel consumption, and a reduction in direct operating cost of more than 5%. The advanced technology E3 system would also permit: compliance with FAR 36 (1977) noise limits, and compliance with 1981 EPA emission standards.

  17. Improving the stability of peptidic radiotracers by the introduction of artificial scaffolds: which structure element is most useful?

    PubMed

    Bacher, Lisa; Fischer, Gabriel; Litau, Shanna; Schirrmacher, Ralf; Wängler, Björn; Baller, Marko; Wängler, Carmen

    2015-08-01

    Peptidic radiotracers are highly potent substances for the specific in vivo imaging of various biological targets with Single Photon Emission Computed Tomography and Positron Emission Tomography. However, some radiolabeled peptides such as bombesin analogs were shown to exhibit only a limited stability, hampering a successful target visualization. One option to positively influence the stability of radiolabeled peptides is the introduction of certain artificial molecular scaffolds. In order to comparatively assess the influence of different structure elements on the stability of radiolabeled peptides and to identify those structure elements being most useful for peptide radiotracer stabilization, several monomeric and dimeric bombesin derivatives were synthesized, exhibiting differing molecular designs and the chelator NODAGA for (68) Ga-labeling. The radiolabeled peptides were evaluated regarding their in vitro stability in human serum to determine the influence of the introduced molecular scaffolds on the peptides' serum stabilities. The results of the evaluations showed that the introduction of scaffold structures and the overall molecular design have a substantial impact on the stabilities of the resulting peptidic radiotracers. But besides some general trends found using certain scaffold structures, the obtained results point to the necessity to empirically assess their influence on stability for each susceptible peptidic radiotracer individually. PMID:26219022

  18. Structural efficiency study of graphite-epoxy aircraft rib structures

    NASA Technical Reports Server (NTRS)

    Swanson, Gary D.; Gurdal, Zafer; Starnes, James H., Jr.

    1988-01-01

    Attention is given to the structural efficiencies obtainable with optimally designed graphite/epoxy wing rib panel configurations that are potentially economically manufacturable. Some ribs are commonly used as fuel cell closeout panels, and are accordingly subjected to out-of-plane pressure loads in addition to the in-plane axial compressive and shear loads resulting from the wing loading. The present minimum-weight panel designs satisfy buckling and strength constraints for wing rib panels subjected to a wide range of combined load conditions.

  19. Study on Efficiency Improvement of Hermetic Rotary Compressors

    NASA Astrophysics Data System (ADS)

    Matsushima, Masatoshi; Nomura, Tomohiro; Nishimura, Nobuya; Iyota, Hiroyuki; Inaba, Koichi

    This research was conducted in order to better identify the torque loss of a hermetic rotary compressor for one revolution, and to directly obtain the actual shaft power of the compressor. A testing compressor and a gas cycle type simplified calorimeter were developed for direct measurement of the compressor torque. A strain gauge was stuck on the shaft between a compressor and a motor. Thus, the compressor torque could be measured directly by the strain gauge and data were transmitted to out of the compressor's vessel through a slip ring. Rotational speed of the compressor was measured by using a gap sensor also. From these measurement results, actual shaft power was calculated experimentally. On the other hand, effective compressive torque for compressing refrigerant gas was predicted theoretically. From both experimental and theoretical results, torque loss of the compressor was determined as the difference of the compressor torque from the effective compressive torque. Consequently, a loss of over-compression could be revealed from the torque loss experimentally. Furthermore, overall adiabatic efficiencies of compressors obtained by the actual shaft power were 1.1∼3.5% higher than former overall adiabatic efficiencies obtained by the motor output.

  20. Development of kit formulations for (99m) TcN-MPO: a cationic radiotracer for myocardial perfusion imaging.

    PubMed

    Zheng, Yumin; Ji, Shundong; Tomaselli, Elena; Liu, Shuang

    2014-07-01

    The objective of this study was to develop a kit formulation for [(99m) TcN(mpo)(PNP5)](+) (MPO = 2-mercaptopyridine oxide), ((99m) TcN-MPO) to support its clinical evaluations as a SPECT radiotracer. Radiolabeling studies were performed using three different formulations (two-vial formulation and single-vial formulations with/without SnCl2 ) to explore the factors influencing radiochemical purity (RCP) of (99m) TcN-MPO. We found that the most important factor affecting the RCP of (99m) TcN-MPO was the purity of PNP5. (99m) TcN-MPO was prepared >98% RCP (n = 20) using the two-vial formulation. For single-vial formulations with/without SnCl2 , β-cyclodextrin (β-CD) is particularly useful as a stabilizer for PNP5. The RCP of (99m) TcN-MPO was 95-98% using β-CD, but its RCP was only 90-93% with γ-cyclodextrin (γ-CD). It seems that PNP5 fits better into the inner cavity of β-CD, which forms more stable inclusion complex than γ-CD in the single-vial formulations. The results from biodistribution and imaging studies in Sprague-Dawley rats clearly demonstrated biological equivalence of three different formulations. Single photon-emission computed tomography data suggested that high quality images could be obtained at 0-30-min post-injection without significant interference from the liver radioactivity. Considering the ease for (99m) Tc-labeling and high RCP of (99m) TcN-MPO, the non-SnCl2 single-vial formulation is an attractive choice for future clinical studies. PMID:25070025

  1. Structural efficiency study of composite wing rib structures

    NASA Technical Reports Server (NTRS)

    Swanson, Gary D.; Gurdal, Zafer; Starnes, James H., Jr.

    1988-01-01

    A series of short stiffened panel designs which may be applied to a preliminary design assessment of an aircraft wing rib is presented. The computer program PASCO is used as the primary design and analysis tool to assess the structural efficiency and geometry of a tailored corrugated panel, a corrugated panel with a continuous laminate, a hat stiffened panel, a blade stiffened panel, and an unstiffened flat plate. To correct some of the shortcomings in the PASCO analysis when shear is present, a two step iterative process using the computer program VICON is used. The loadings considered include combinations of axial compression, shear, and lateral pressure. The loading ranges considered are broad enough such that the designs presented may be applied to other stiffened panel applications. An assessment is made of laminate variations, increased spacing, and nonoptimum geometric variations, including a beaded panel, on the design of the panels.

  2. [The randomized study of efficiency of preoperative photodynamic].

    PubMed

    Akopov, A L; Rusanov, A A; Molodtsova, V P; Gerasin, A V; Kazakov, N V; Urtenova, M A; Chistiakov, I V

    2013-01-01

    The authors made a prospective randomized comparison of results of preoperative photodynamic therapy (PhT) with chemotherapy, preoperative chemotherapy in initial unresectable central non-small cell lung cancer in stage III. The efficiency and safety of preoperative therapy were estimated as well as the possibility of subsequent surgical treatment. The research included patients in stage IIIA and IIIB of central non-small cell lung cancer with lesions of primary bronchi and lower section of the trachea, which initially were unresectable, but potentially the patients could be operated on after preoperative treatment. The photodynamic therapy was performed using chlorine E6 and the light of wave length 662 nm. Since January 2008 till December 2011,42 patients were included in the research, 21 patients were randomized in the group for photodynamic therapy and 21--in group without PhT. These groups were compared according to their sex, age, stage of the disease and histological findings. After nonadjuvant treatment the remissions were reached in 19 (90%) patients of the group with PhT and in 16 (76%) patients without PhT and all the patients were operated on. The explorative operations were made on 3 patients out of 16 operated on in the group without PhT (19%). In the group PhT 14 pneumonectomies and 5 lobectomies were perfomed opposite 10 pneumonectomies and 3 lobectomies in group without PhT. The degree of radicalism of resection appears to be reliably higher in the group PhT (RO-89%, R1-11% as against RO-54%, R1-46% in group without PhT), p = 0.038. The preoperative endobronchial PhT conducted with chemotherapy was characterized by efficiency and safety, allowed the surgical treatment and elevated the degree of radicalism of this treatment in selected patients, initially assessed as unresectable. PMID:23808222

  3. Enhancing health programme efficiency: a Cambodian case study.

    PubMed

    Stuer, F

    1998-09-01

    In 1995, the Cambodian Urban Health Care Association (CUHCA) was set up as facilitator between private health care providers and patients, guaranteeing good quality health care and fair pricing to patients and providing training and logistic support to providers. Providers were engaged on a fee-for-service basis and competition encouraged. CUHCA's objectives followed the same line of thought as the 1993 World Development Report, aiming at influencing the unregulated private health care market through competition mechanisms. But soon after the start of the project the basic problem was recognized to be not the absence of effective government regulation but rather that consumers lack the requisite knowledge to make good choices in the market for health services. CUHCA had not adequately addressed the demand for health services. The original supply-side strategy of improving health services by increasing competition was a failure. In order to improve CUHCA's health programme efficiency the association's objectives were subsequently redefined and its functioning reorganized. CUHCA now tries to educate consumers and provides good quality services so that consumers will be able to act on the basis of their newly acquired knowledge. CUHCA's health centres serve as model clinics for first-line health care. Community educators organize information, education and communication (IEC) activities. Staff help school teachers to improve formal health education in schools and CUHCA assists local leaders in sanitation development. Only full-time personnel are employed, encouraging team spirit and communication with the target population. Salaries are based on team performance. The CUHCA programme demonstrates that, depending on the market situation, health programme models need to address both the supply and the demand for services in order to be efficient. Where consumers lack essential knowledge to make appropriate choices in the health service market, interventions should focus

  4. Working against time: Rapid radiotracer synthesis and imaging the human brain

    SciTech Connect

    Fowler, J.S.; Wolf, A.P.

    1997-04-01

    In this Account, the authors describe some advances in radiotracer chemistry which have made it possible to probe the chemical anatomy of the human brain while working within a very restricted time scale. Though we highlight research from our laboratory, it is important to emphasize that advances in PET brain imaging have come from many laboratories throughout the world. Thus, for a more comprehensive treatment of PET technology the reader is referred to textbooks and review articles cited in this Account. Since many of the milestones in delineating biochemical transformations and the movement of drugs in the human brain have involved radiosynthesis with carbon-11 and fluorine-18, we focus on these two isotopes. 50 refs., 6 figs., 1 tab.

  5. Distribution of nickel hydroxide in sintered nickel plaques measured by radiotracer method during electroimpregnation

    SciTech Connect

    Ng, P.K.; Schneider, E.W.

    1986-01-01

    Sintered nickel positive electrodes were prepared by electroimpregnating nickel hydroxide inside a porous nickel plaque in a nickel nitrate solution. The distribution of nickel hydroxide inside the plaque was measured using a radio-tracer method with /sup 63/Ni as the radioactivity source. Autoradiography and ..beta.. counting were used to follow qualitative and quantitative distributions, respectively, of the pore filling process. Relatively uniform distribution was observed at low current density, and the precipitation of Ni(OH)/sub 2/ extends to the center of the plaque. At high current density, most of the Ni(OH)/sub 2/ aggregated in the region just underneath the plaque surface, causing a somewhat nonuniform distribution. Nickel hydroxide also precipitates heavily on the surface of the plaque at high current density, reducing the penetration of electrolyte to the inside of the plaque.

  6. Database generation and exploitation for efficient and intensive simulation studies

    NASA Astrophysics Data System (ADS)

    Miorelli, Roberto; Artusi, Xavier; Abdessalem, Anis Ben; Reboud, Christophe

    2016-02-01

    This communication proposes a study on the application of surrogate modelling for intensive simulations studies. In particular, stochastic inversion approaches, model assisted probability of detection (MAPOD) and sensitivity analysis studies are addressed. Some illustrative examples, corresponding to real applications and involving different non-destructive testing methods, are also presented.

  7. 2'[(18)F]-fluoroethylrhodamine B is a promising radiotracer to measure P-glycoprotein function.

    PubMed

    Trencsényi, György; Kertész, István; Krasznai, Zoárd T; Máté, Gábor; Szalóki, Gábor; Szabó Judit, P; Kárpáti, Levente; Krasznai, Zoltán; Márián, Teréz; Goda, Katalin

    2015-07-10

    In vivo detection of the emergence of P-glycoprotein (Pgp) mediated multidrug resistance in tumors could be beneficial for patients treated with anticancer drugs. PET technique in combination with appropriate radiotracers could be the most convenient method for detection of Pgp function. Rhodamine derivatives are validated fluorescent probes for measurement of mitochondrial membrane potential and also Pgp function. The aim of this study was to investigate whether 2'[(18)F]-fluoroethylrhodamine B ((18)FRB) a halogenated rhodamine derivative previously synthesized for PET assessment of myocardial perfusion preserved its Pgp substrate character. ATPase assay as well as accumulation experiments carried out using Pgp(+) and Pgp(-) human gynecologic (A2780/A2780(AD) and KB-3-1/KB-V1) and a mouse fibroblast cell pairs (NIH 3T3 and NIH 3T3 MDR1) were applied to study the interaction of (18)FRB with Pgp. ATPase assay proved that (18)FRB is a high affinity substrate of Pgp. Pgp(-) cells accumulated the (18)FRB rapidly in accordance with its lipophilic character. Dissipation of the mitochondrial proton gradient by a proton ionophore CCCP decreased the accumulation of rhodamine 123 (R123) and (18)FRB into Pgp(-) cells. Pgp(+) cells exhibited very low R123 and (18)FRB accumulation (around 1-8% of the Pgp(-) cell lines) which was not sensitive to the mitochondrial proton gradient; rather it was increased by the Pgp inhibitor cyclosporine A (CsA). Based on the above data we conclude that (18)FRB is a high affinity Pgp substrate and consequently a potential PET tracer to detect multidrug resistant tumors as well as the function of physiological barriers expressing Pgp. PMID:25857708

  8. Investigating the pharmacokinetics and biological distribution of silver-loaded polyphosphoester-based nanoparticles using 111Ag as a radiotracer

    PubMed Central

    Aweda, Tolulope A.; Zhang, Shiyi; Mupanomunda, Chiedza; Burkemper, Jennifer; Heo, Gyu Seong; Bandara, Nilantha; Lin, Mai; Cutler, Cathy S.; Cannon, Carolyn L.; Youngs, Wiley; Wooley, Karen L.; Lapi, Suzanne E.

    2015-01-01

    Purified 111Ag was used as a radiotracer to investigate silver loading and release, pharmacokinetics and biodistribution of polyphosphoester-based degradable shell crosslinked knedel-like (SCK) nanoparticles as a comparison to the previously reported small molecule, N-heterocyclic silver carbene complex analogue (SCC1) for the delivery of therapeutic silver ions in mouse models. Biodistribution studies were conducted by aerosol administration of 111Ag acetate, [111Ag]SCC1 and [111Ag]SCK doses directly into the lungs of C57BL/6 mice. Nebulization of the 111Ag antimicrobials resulted in an average uptake of 1.07 ± 0.12% of the total aerosolized dose given per mouse. The average dose taken into the lungs of mice was estimated to be 2.6 ± 0.3% of the dose inhaled per mouse for [111Ag]SCC1 and twice as much dose was observed for the [111Ag]SCKs (5.0 ± 0.3% and 5.9 ± 0.8% for [111Ag]aSCK and [111Ag]zSCK, respectively) at 1 h post administration (p.a.). [111Ag]SCKs also exhibited higher dose retention in the lungs; 62 – 68% for [111Ag]SCKs and 43% for [111Ag]SCC1 of the initial 1 h dose was observed in the lungs at 24 h post administration (p.a.). This study demonstrates the utility of 111Ag as a useful tool for monitoring the pharmacokinetics of silver loaded antimicrobials in vivo. PMID:25952472

  9. Investigating the pharmacokinetics and biological distribution of silver-loaded polyphosphoester-based nanoparticles using (111) Ag as a radiotracer.

    PubMed

    Aweda, Tolulope A; Zhang, Shiyi; Mupanomunda, Chiedza; Burkemper, Jennifer; Heo, Gyu Seong; Bandara, Nilantha; Lin, Mai; Cutler, Cathy S; Cannon, Carolyn L; Youngs, Wiley J; Wooley, Karen L; Lapi, Suzanne E

    2015-05-30

    Purified (111) Ag was used as a radiotracer to investigate silver loading and release, pharmacokinetics, and biodistribution of polyphosphoester-based degradable shell crosslinked knedel-like (SCK) nanoparticles as a comparison to the previously reported small molecule, N-heterocyclic silver carbene complex analog (SCC1) for the delivery of therapeutic silver ions in mouse models. Biodistribution studies were conducted by aerosol administration of (111) Ag acetate, [(111) Ag]SCC1, and [(111) Ag]SCK doses directly into the lungs of C57BL/6 mice. Nebulization of the (111) Ag antimicrobials resulted in an average uptake of 1.07 ± 0.12% of the total aerosolized dose given per mouse. The average dose taken into the lungs of mice was estimated to be 2.6 ± 0.3% of the dose inhaled per mouse for [(111) Ag]SCC1 and twice as much dose was observed for the [(111) Ag]SCKs (5.0 ± 0.3% and 5.9 ± 0.8% for [(111) Ag]aSCK and [(111) Ag]zSCK, respectively) at 1 h post administration (p.a.). [(111) Ag]SCKs also exhibited higher dose retention in the lungs; 62-68% for [(111) Ag]SCKs and 43% for [(111) Ag]SCC1 of the initial 1 h dose were observed in the lungs at 24 h p.a.. This study demonstrates the utility of (111) Ag as a useful tool for monitoring the pharmacokinetics of silver-loaded antimicrobials in vivo. PMID:25952472

  10. Spin Contrast Variation Study of Fuel-efficient Tire Rubber

    NASA Astrophysics Data System (ADS)

    Noda, Yohei; Yamaguchi, Daisuke; Hashimoto, Takeji; Shamoto, Shin-ichi; Koizumi, Satoshi; Yuasa, Takeshi; Tominaga, Tetsuo; Sone, Takuo

    The scattering length of a proton against a polarized neutron depends strongly on the polarization of proton spins (PH). This dependence can be utilized for contrast variation in small angle neutron scattering (SANS). We applied this spin contrast variation technique to a silica-filled SBR rubber specimen, which is widely used for tread rubber of fuel-efficient tires. For realizing high PH, we used dynamic nuclear polarization (DNP) technique, in which large polarization of electron spin at low temperature and high magnetic field is transferred to proton spin by microwave irradiation with a tuned frequency. As this electron spin source, we doped stable radical TEMPO (2,2,6,6-tetramethyl piperidine 1-oxyl) into the rubber sample by use of a vapor sorption technique. For the TEMPO-doped rubber sample, SANS measurements were conducted at PH = -20%, 0%, and +13%, with almost fully polarized neutron beam %) with its wavelength of 6.5±0.6 Å. The SANS profile clearly changed as a function of PH, which can be explained by the PH dependence of the neutron scattering length densities of the main three components (SBR, silica and zinc oxide). By a linear transformation of the profiles obtained at the three different PH values, we successfully determined the partial scattering function of silica, which reflects the aggregation of silica particles.

  11. High efficient ZnO nanowalnuts photocatalyst: A case study

    SciTech Connect

    Yan, Feng; Zhang, Siwen; Liu, Yang; Liu, Hongfeng; Qu, Fengyu; Cai, Xue; Wu, Xiang

    2014-11-15

    Highlights: • Walnut-like ZnO nanostructures are synthesized through a facile hydrothermal method. • Morphologies and microstructures of the as-obtained ZnO products were investigated. • The photocatalytic results demonstrate that methyl orange (MO) aqueous solution can be degraded over 97% after 45 min under UV light irradiation. - Abstract: Walnut-like ZnO nanostructures are successfully synthesized through a facile hydrothermal method. The structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic properties of ZnO nanowalnuts are investigated by photodegradating several organic dyes, such as Congo red (CR), methyl orange (MO) and eosin red aqueous solutions under UV irradiation, respectively. The results demonstrate that methyl orange (MO) aqueous solution can be degraded over 97% after 45 min under UV light irradiation. In addition, eosin red and Congo red (CR) aqueous solution degradation experiments are also conducted in the same condition, respectively. It showed that ZnO nanowalnuts represent high photocatalytic activities with a degradation efficiency of 87% for CR with 115 min of irradiation and 97% for eosin red with 55 min of irradiation. The reported ZnO products may be promising candidates as the photocatalysts in waste water treatment.

  12. Study of efficient video compression algorithms for space shuttle applications

    NASA Technical Reports Server (NTRS)

    Poo, Z.

    1975-01-01

    Results are presented of a study on video data compression techniques applicable to space flight communication. This study is directed towards monochrome (black and white) picture communication with special emphasis on feasibility of hardware implementation. The primary factors for such a communication system in space flight application are: picture quality, system reliability, power comsumption, and hardware weight. In terms of hardware implementation, these are directly related to hardware complexity, effectiveness of the hardware algorithm, immunity of the source code to channel noise, and data transmission rate (or transmission bandwidth). A system is recommended, and its hardware requirement summarized. Simulations of the study were performed on the improved LIM video controller which is computer-controlled by the META-4 CPU.

  13. Integrated energy management study. Energy efficient transport program

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The Integrated Energy Management (IEM) Study investigated the practicality and feasibility of a closed-loop energy management system for transport aircraft. The study involved: (1) instrumentation and collection of in-flight data for a United Airlines 727-200 flying 80 revenue flights throughout the United Airlines network,(2) analysis of the in-flight data to select representative city pairs and establish operational procedures employed in flying a reference flight profile, (3) simulation of the reference profile in a fast-time model to verify the model and establish performance values against which to measure IEM benefits, (4) development of IEM algorithms, and (5) assessment of the IEM concept.

  14. Stress and efficiency studies in edge-defined film-fed growth

    NASA Technical Reports Server (NTRS)

    Kalejs, J.

    1986-01-01

    The progress was reviewed for stress and efficiency studies of edge-defined film-fed growth (EFG) material. Effort was concentrated on the definition of condiitions that will reduce stress, on quantifying dislocation electrical activity and limits on solar cell efficiency, and on studying the effects of dopants on EFG characteristics.

  15. Development of gamma emitting receptor binding radiotracers for imaging the brain and pancreas. Final technical progress report, March 1, 1988--May 31, 1993

    SciTech Connect

    1996-01-01

    This document give paragraph synopses of results in research on brain and pancreas imaging, using radiotracers. General catagories of research included chemistry, pharmacology, imaging physics, and kinetic modeling. A list of publications is included

  16. A pilot study of energy efficient air cleaning for ozone

    SciTech Connect

    Gundel, Lara A.; Sullivan, Douglas P.; Katsapov, Gregory Y.; Fisk, William J.

    2002-11-01

    A laboratory pilot study has been undertaken with the material that showed the most promise (high capacity and low pressure drop) based on the literature review and associated calculations. The best-performing air cleaner was a commercially available pleated filter that contained a thin layer of small activated carbon particles between two sheets of non-woven fibrous webbing. We will refer to this unit as the ''ozone filter'' although it is marketed for removal of volatile organic compounds (VOCs) from automobile passenger compartments. This pilot study strongly suggests that ozone air cleaning can be practical in commercial air handling systems; however, further tests are needed to assess air cleaner performance under a wider range of conditions.

  17. An efficient empirical Bayes method for genomewide association studies.

    PubMed

    Wang, Q; Wei, J; Pan, Y; Xu, S

    2016-08-01

    Linear mixed model (LMM) is one of the most popular methods for genomewide association studies (GWAS). Numerous forms of LMM have been developed; however, there are two major issues in GWAS that have not been fully addressed before. The two issues are (i) the genomic background noise and (ii) low statistical power after Bonferroni correction. We proposed an empirical Bayes (EB) method by assigning each marker effect a normal prior distribution, resulting in shrinkage estimates of marker effects. We found that such a shrinkage approach can selectively shrink marker effects and reduce the noise level to zero for majority of non-associated markers. In the meantime, the EB method allows us to use an 'effective number of tests' to perform Bonferroni correction for multiple tests. Simulation studies for both human and pig data showed that EB method can significantly increase statistical power compared with the widely used exact GWAS methods, such as GEMMA and FaST-LMM-Select. Real data analyses in human breast cancer identified improved detection signals for markers previously known to be associated with breast cancer. We therefore believe that EB method is a valuable tool for identifying the genetic basis of complex traits. PMID:26582716

  18. Energy Efficient Engine program advanced turbofan nacelle definition study

    NASA Technical Reports Server (NTRS)

    Howe, David C.; Wynosky, T. A.

    1985-01-01

    Advanced, low drag, nacelle configurations were defined for some of the more promising propulsion systems identified in the earlier Benefit/Cost Study, to assess the benefits associated with these advanced technology nacelles and formulate programs for developing these nacelles and low volume thrust reversers/spoilers to a state of technology readiness in the early 1990's. The study results established the design feasibility of advanced technology, slim line nacelles applicable to advanced technology, high bypass ratio turbofan engines. Design feasibility was also established for two low volume thrust reverse/spoiler concepts that meet or exceed the required effectiveness for these engines. These nacelle and thrust reverse/spoiler designs were shown to be applicable in engines with takeoff thrust sizes ranging from 24,000 to 60,000 pounds. The reduced weight, drag, and cost of the advanced technology nacelle installations relative to current technology nacelles offer a mission fuel burn savings ranging from 3.0 to 4.5 percent and direct operating cost plus interest improvements from 1.6 to 2.2 percent.

  19. Study of parallel efficiency in message passing environments

    SciTech Connect

    Hanebutte, U.R.; Tatsumi, Masahiro

    1996-03-01

    A benchmark test using the Message Passing Interface (MPI, an emerging standard for writing message passing programs) has been developed, to study parallel performance in message passing environments. The test is comprised of a computational task of independent calculations followed by a round-robin data communication step. Performance data as a function of computational granularity and message passing requirements are presented for the IBM SPx at Argonne National Laboratory and for a cluster of quasi-dedicated SUN SPARC Station 20`s. In the later portion of the paper a widely accepted communication cost model combined with Amdahl`s law is used to obtain performance predictions for uneven distributed computational work loads.

  20. A study of the efficiency of hydrogen liquefaction

    NASA Technical Reports Server (NTRS)

    Baker, C. R.; Shaner, R. L.

    1976-01-01

    The use of liquid hydrogen as a jet aircraft fuel has a number of environmental and technological advantages over conventional fuels. The liquefaction of hydrogen requires a large expenditure of energy. There are many inefficiencies that are a part of any practical liquefaction process. Current technology was investigated for the best available system. Parametric studies were made to identify where inefficiencies occur and to optimize and integrate the component parts. Flowsheets are presented for a module that produces 250 tons per day of liquid hydrogen. Approximately ten of these modules is needed for a major airport in the 1990's. The advantages of producing a product with a minimum amount of ortho to para hydrogen conversion are pointed out. The optimum degree of conversion was determined for a liquid hydrogen product that will be used within a given time. An assessment was made regarding the potentials for improvement of the processing schemes and equipment over the next 10 to 25 years.

  1. Optimal design study of high efficiency indium phosphide space solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1990-01-01

    Recently indium phosphide solar cells have achieved beginning of life AMO efficiencies in excess of 19 pct. at 25 C. The high efficiency prospects along with superb radiation tolerance make indium phosphide a leading material for space power requirements. To achieve cost effectiveness, practical cell efficiencies have to be raised to near theoretical limits and thin film indium phosphide cells need to be developed. The optimal design study is described of high efficiency indium phosphide solar cells for space power applications using the PC-1D computer program. It is shown that cells with efficiencies over 22 pct. AMO at 25 C could be fabricated by achieving proper material and process parameters. It is observed that further improvements in cell material and process parameters could lead to experimental cell efficiencies near theoretical limits. The effect of various emitter and base parameters on cell performance was studied.

  2. Schizophrenia symptoms and brain network efficiency: A resting-state fMRI study.

    PubMed

    Su, Tsung-Wei; Hsu, Tun-Wei; Lin, Yi-Ching; Lin, Ching-Po

    2015-11-30

    Schizophrenia is a condition marked by a disrupted brain functional network. In schizophrenia, the brain network is characterized by reduced distributed information processing efficiency; however, the correlation between information processing efficiency and the symptomatology of schizophrenia remains unclear. Few studies have examined path length efficiencies in schizophrenia. In this study, we examined small-world network metrics computed from resting state functional magnetic resonance imaging data collected from 49 patients with schizophrenia and 28 healthy people. We calculated brain network efficiency using graph theoretical analysis of the networks of brain areas, as defined by the Automated Anatomical Labeling parcellation scheme, and investigated efficiency correlations by using the 5-factor model of psychopathology, which considers the various domains of schizophrenic symptoms and might also consider discrete pathogenetic processes. The global efficiency of the resting schizophrenic brains was lower than that of the healthy controls, but local efficiency did not differ between the groups. The severity of psychopathology, negative symptoms, and depression and anxiety symptoms were correlated with global efficiency in schizophrenic brains. The severity of psychopathology was correlated with increased network efficiency from short-range connections, but not networks from long-range connections. Our findings indicate that schizophrenic psychopathology is correlated with brain network information processing efficiency. PMID:26409574

  3. A study of improvements in silicon solar cell efficiency due to various geometrical and doping modifications

    NASA Technical Reports Server (NTRS)

    Dunbar, P. M.; Hauser, J. R.

    1976-01-01

    This paper presents the results of continued studies of silicon solar cell operation and limitations. The objective of this paper is to report on geometrical and doping changes in silicon solar cells which result in predictions of high efficiencies. Efficiencies as high as 20 per cent (uncorrected for metal coverage and ohmic sheet resistance) have been calculated for optimized cells. The conditions required to achieve these efficiency values are discussed.

  4. Semi-automated lab-on-a-chip for dispensing GA-68 radiotracers

    SciTech Connect

    Weinberg, Irving

    2014-03-12

    We solved a technical problem that is hindering American progress in molecular medicine, and restricting US citizens from receiving optimal diagnostic care. Specifically, the project deals with a mother/daughter generator of positron-emitting radiotracers (Ge-68/Ga-68). These generator systems are approved in Europe but cannot be used in the USA, because of safety issues related to possible breakthrough of long-lived Ge-68 (mother) atoms. Europeans have demonstrated abilities of Ga-68-labeled radiotracers to image cancer foci with high sensitivity and specificity, and to use such methods to effectively plan therapy.The USA Food and Drug Administration (FDA) and Nuclear Regulatory Commission (NRC) have taken the position that every patient administration of Ga-68 should be preceded by an assay demonstrated that Ge-68 breakthrough is within acceptable limits. Breakthrough of parent elements is a sensitive subject at the FDA, as evidenced by the recent recall of Rb-82 generators due to inadvertent administrations of Sr-82. Commercially, there is no acceptable rapid method for assaying breakthrough of Ge-68 prior to each human administration. The gamma emissions of daughter Ga-68 have higher energies than the parent Ge-68, so that the shielding assays typically employed for Mo-99/Tc-99m generators cannot be applied to Ga-68 generators. The half-life of Ga-68 is 68 minutes, so that the standard 10-half-life delay (used to assess breakthrough in Sr-82/Rb-82 generators) cannot be applied to Ga-68 generators. As a result of the aforementioned regulatory requirements, Ga-68 generators are sold in the USA for animal use only.The American clinical community’s inability to utilize Ga-68 generators impairs abilities to treat patients domestically, and puts the USA at a disadvantage in developing exportable products. The proposed DOE project aimed to take advantage of recent technological advances developed for lab-on-a-chip (LOC) applications. Based on our experiences

  5. BWR Spent Nuclear Fuel Interfacial Bonding Efficiency Study

    SciTech Connect

    Wang, Jy-An John; Jiang, Hao

    2015-04-30

    The objective of this project is to perform a systematic study of spent nuclear fuel (SNF, also known as “used nuclear fuel” [UNF]) integrity under simulated transportation environments using the Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT) hot-cell testing technology developed at Oak Ridge National Laboratory (ORNL) in August 2013. Under Nuclear Regulatory Commission (NRC) sponsorship, ORNL completed four benchmark tests, four static tests, and twelve dynamic or cycle tests on H. B. Robinson (HBR) high burn-up (HBU) fuel. The clad of the HBR fuels was made of Zircaloy-4. Testing was continued in fiscal year (FY) 2014 using Department of Energy (DOE) funds. Additional CIRFT testing was conducted on three HBR rods; two specimens failed, and one specimen was tested to over 2.23 × 107 cycles without failing. The data analysis on all the HBR SNF rods demonstrated that it is necessary to characterize the fatigue life of the SNF rods in terms of (1) the curvature amplitude and (2) the maximum absolute of curvature extremes. The maximum extremes are significant because they signify the maximum tensile stress for the outer fiber of the bending rod. CIRFT testing has also addressed a large variation in hydrogen content on the HBR rods. While the load amplitude is the dominant factor that controls the fatigue life of bending rods, the hydrogen content also has an important effect on the lifetime attained at each load range tested. In FY 15, eleven SNF rod segments from the Limerick BWR were tested using the ORNL CIRFT equipment; one test under static conditions and ten tests under dynamic loading conditions. Under static unidirectional loading, a moment of 85 N·m was obtained at a maximum curvature of 4.0 m-1. The specimen did not show any sign of failure during three repeated loading cycles to a similar maximum curvature. Ten cyclic tests were conducted with amplitudes varying from 15.2 to 7.1 N·m. Failure was observed in nine of

  6. Development of indazolylpyrimidine derivatives as high-affine EphB4 receptor ligands and potential PET radiotracers.

    PubMed

    Ebert, Kristin; Wiemer, Jens; Caballero, Julio; Köckerling, Martin; Steinbach, Jörg; Pietzsch, Jens; Mamat, Constantin

    2015-09-01

    Due to their essential role in the pathogenesis of cancer, members of the Eph (erythropoietin-producing hepatoma cell line-A2) receptor tyrosine kinase family represent promising candidates for molecular imaging. Thus, the development and preparation of novel radiotracers for the noninvasive imaging of the EphB4 receptor via positron emission tomography (PET) is described. First in silico investigations with the indazolylpyrimidine lead compound which is known to be highly affine to EphB4 were executed to identify favorable labeling positions for an introduction of fluorine-18 to retain the affinity. Based on this, reference compounds as well as precursors were developed and labeled with carbon-11 and fluorine-18, respectively. For this purpose, a protecting group strategy essentially had to be generated to prevent unwanted methylation and to enable the introduction of fluorine-18. Further, a convenient radiolabeling strategy using [(11)C]methyl iodide was established which afforded the isotopically labeled radiotracer in 30-35% RCY (d.c.) which is identical with the original inhibitor molecule. A spiro ammonium precursor was prepared for radiolabeling with fluorine-18. Unfortunately, the labeling did not lead to the desired (18)F-radiotracer under the chosen conditions. PMID:26189032

  7. Undergraduate Degree Completion: A Study of Time and Efficiency to Degree

    ERIC Educational Resources Information Center

    Runyan, Lisa M.

    2011-01-01

    The purpose of this quantitative study was to examine time and efficiency to undergraduate degree completion. Four dependent variables were examined including semesters enrolled, semesters elapsed, graduation efficiency index (GEI), and alternative GEI. Many independent variables were assessed to determine if they had a correlation to time or…

  8. Efficiency of a Care Coordination Model: A Randomized Study with Stroke Patients

    ERIC Educational Resources Information Center

    Claiborne, Nancy

    2006-01-01

    Objectives: This study investigated the efficiency of a social work care coordination model for stroke patients. Care coordination addresses patient care and treatment resources across the health care system to reduce risk, improve clinical outcomes, and maximize efficiency. Method: A randomly assigned, pre-post experimental design measured…

  9. Transfection efficiency of chitosan and thiolated chitosan in retinal pigment epithelium cells: A comparative study

    PubMed Central

    Oliveira, Ana V.; Silva, Andreia P.; Bitoque, Diogo B.; Silva, Gabriela A.; Rosa da Costa, Ana M.

    2013-01-01

    OBJECTIVE: Gene therapy relies on efficient vector for a therapeutic effect. Efficient non-viral vectors are sought as an alternative to viral vectors. Chitosan, a cationic polymer, has been studied for its gene delivery potential. In this work, disulfide bond containing groups were covalently added to chitosan to improve the transfection efficiency. These bonds can be cleaved by cytoplasmic glutathione, thus, releasing the DNA load more efficiently. MATERIALS AND METHODS: Chitosan and thiolated chitosan nanoparticles (NPs) were prepared in order to obtain a NH3+:PO4− ratio of 5:1 and characterized for plasmid DNA complexation and release efficiency. Cytotoxicity and gene delivery studies were carried out on retinal pigment epithelial cells. RESULTS: In this work, we show that chitosan was effectively modified to incorporate a disulfide bond. The transfection efficiency of chitosan and thiolated chitosan varied according to the cell line used, however, thiolation did not seem to significantly improve transfection efficiency. CONCLUSION: The apparent lack of improvement in transfection efficiency of the thiolated chitosan NPs is most likely due to its size increase and charge inversion relatively to chitosan. Therefore, for retinal cells, thiolated chitosan does not seem to constitute an efficient strategy for gene delivery. PMID:23833516

  10. The Super Efficient Refrigerator Program: Case study of a Golden Carrot program

    SciTech Connect

    Eckert, J B

    1995-07-01

    The work in this report was conducted by the Analytic Studies Division (ASD) of the National Renewable Energy Laboratory (NREL) for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy, Office of Building Technologies. This case study describes the development and implementation of the Super Efficient Refrigerator Program (SERP), which awarded $30 million to the refrigerator manufacturer that developed and commercialized a refrigerator that exceeded 1993 federal efficiency standards by at least 25%. The program was funded by 24 public and private utilities. As the first Golden Carrot program to be implemented in the United States, SERP was studied as an example for future `market-pull` efforts.

  11. Methodological considerations regarding the use of inorganic 197Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment

    USGS Publications Warehouse

    Perez, Catan S.; Guevara, S.R.; Marvin-DiPasquale, M.; Magnavacca, C.; Cohen, I.M.; Arribere, M.

    2007-01-01

    Methodological considerations on the determination of benthic methyl-mercury (CH3Hg) production potentials were investigated on lake sediment, using 197Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and ??-irradiation. Flash freezing showed similar CH3Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with ??-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated 197Hg(II) carry-over in the organic extraction and/or [197Hg]CH3Hg produced via abiotic reactions. Two CH3Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO4 and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over. ?? 2007 Elsevier Ltd. All rights reserved.

  12. Production of 191Pt radiotracer with high specific activity for the development of preconcentration procedures

    NASA Astrophysics Data System (ADS)

    Parent, M.; Strijckmans, K.; Cornelis, R.; Dewaele, J.; Dams, R.

    1994-04-01

    A radiotracer of Pt with suitable nuclear characteristics and high specific activity (i.e. activity to mass ratio) is a powerful tool when developing preconcentration methods for the determination of base-line levels of Pt in e.g. environmental and biological samples. Two methods were developed for the production of 191Pt with high specific activity and radionuclidic purity: (1) via the 190Pt(n, γ) 191Pt reaction by neutron irradiation of enriched Pt in a nuclear reactor at high neutron fluence rate and (2) via the 191Ir(p, n) 191Pt reaction by proton irradiation of natural Ir with a cyclotron, at an experimentally optimized proton energy. For the latter method it was necessary to separate Pt from the Ir matrix. For that reason either liquid-liquid extraction with dithizone or adsorption chromatography were used. The yields, the specific activities and the radionuclidic purities were experimentally determined as a function of the proton energy and compared to the former method. The half-life of 191Pt was accurately determined to be 2.802 ± 0.025 d.

  13. Calcium carbonate scaling kinetics determined from radiotracer experiments with calcium-47

    SciTech Connect

    Turner, C.W.; Smith, D.W.

    1998-02-01

    The deposition of calcium carbonate is one of the principal modes of fouling of the heat-transfer surface of a fresh-water-cooled heat exchanger. The deposition rate of calcium carbonate on a heat-transfer surface has been measured using a calcium-47 radiotracer and compared to the measured rate of thermal fouling. The crystalline phase of calcium carbonate that precipitates depends on the degree of supersaturation at the heat-transfer surface, with aragonite precipitating at higher supersaturations and calcite precipitating at lower supersaturations. Whereas the mass deposition rates were constant with time, the thermal fouling rates decreased throughout the course of each experiment as a result of densification of the deposit. It is proposed that the densification was driven by the temperature gradient across the deposit together with the retrograde solubility of calcium carbonate. The temperature dependence of the deposition rate yielded an activation energy of 79 {+-} 4 kJ/mol for the precipitation of calcium carbonate on a heat-transfer surface.

  14. Characterization of fast-decaying PET radiotracers solely through LC-MS/MS of constituent radioactive and carrier isotopologues

    PubMed Central

    2013-01-01

    Background The characterization of fast-decaying radiotracers that are labeled with carbon-11 (t1/2 = 20.38 min), including critical measurement of specific radioactivity (activity per mole at a specific time) before release for use in positron-emission tomography (PET), has relied heavily on chromatographic plus radiometric measurements, each of which may be vulnerable to significant errors. Thus, we aimed to develop a mass-specific detection method using sensitive liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) for identifying 11C-labeled tracers and for verifying their specific radioactivities. Methods The LC-MS/MS was tuned and set up with methods to generate and measure the product ions specific for carbon-11 species and M + 1 carrier (predominantly the carbon-13 isotopologue) in four 11C-labeled tracers. These radiotracers were synthesized and then analyzed before extensive carbon-11 decay. The peak areas of carbon-11 species and M + 1 carrier from the LC-MS/MS measurement and the calculated abundances of carbon-12 carrier and M + 1 radioactive species gave the mole fraction of carbon-11 species in each sample. This value upon multiplication with the theoretical specific radioactivity of carbon-11 gave the specific radioactivity of the radiotracer. Results LC-MS/MS of each 11C-labeled tracer generated the product ion peaks for carbon-11 species and M + 1 carrier at the expected LC retention time. The intensity of the radioactive peak diminished as time elapsed and was undetectable after six half-lives of carbon-11. Measurements of radiotracer-specific radioactivity determined solely by LC-MS/MS at timed intervals gave a half-life for carbon-11 (20.43 min) in excellent agreement with the value obtained radiometrically. Additionally, the LC-MS/MS measurement gave specific radioactivity values (83 to 505 GBq/μmol) in good agreement with those from conventional radiometric methods. Conclusions 11C-Labeled tracers were

  15. Studies of oxygen- and carbon-related defects in high-efficiency silicon solar cells

    NASA Technical Reports Server (NTRS)

    Corbett, J.

    1984-01-01

    Studies were conducted to investigate the vague nature of carbon and oxygen related defects in high efficiency silicon solar cells. High temperature tests were employed to perform these investigations.

  16. Robust Timing Synchronization for Aviation Communications, and Efficient Modulation and Coding Study for Quantum Communication

    NASA Technical Reports Server (NTRS)

    Xiong, Fugin

    2003-01-01

    One half of Professor Xiong's effort will investigate robust timing synchronization schemes for dynamically varying characteristics of aviation communication channels. The other half of his time will focus on efficient modulation and coding study for the emerging quantum communications.

  17. Experimental studies of silver iodide pyrotechnic aerosol ice forming efficiency dynamics

    NASA Astrophysics Data System (ADS)

    Shilin, A. G.; Drofa, A. S.; Ivanov, V. N.; Savchenko, A. V.; Shilin, V. A.

    2013-05-01

    The study concerns the problems connected with the temporal variability of aerosol ice forming activity at introduction into the sub-cloud layer and the comparison of aerosol efficiency of produced pyrotechnic mixtures with different silver contents.

  18. [{sup 11}C]d-threo-Methylphenidate, a new radiotracer for the dopamine transporter. Characterization in baboon and human brain

    SciTech Connect

    Ding, Y.S.; Volkow, N.D.; Fowler, J.S.

    1995-05-01

    dl-threo Methylphenidate (MP, Ritalin) is a psychostimulant drug which binds to the dopamine transporter (DAT). We evaluated [{sup 11}C]d-threo-methylphenidate ([{sup 11}C]d-MP), the more active enantiomer, as a radiotracer for the DAT in baboons and human brain. Stereoselectivity, saturability and pharmacological specificity and reproducibility were examined. Stereoselectivity was examined in baboons by comparing [{sup 11C}]d-MP,[{sup 11}C]l-MP and [{sup 11}C]dl-MP. Unlabeled MP was used to assess the reversibility and saturability of the binding. GBR 12909,{beta}-(4-iodophenyl)tropane-2-carboxylic acid methyl ester ({beta}-CIT), tomoxetine and citalopram were used to assess the specificity of the binding. The ratios between the radioactivity in the striatum to that in cerebellum (ST/CB) were 3.3,2.2 and 1.1 for [{sup 11}C]d-MP,[{sup 11}C]dl-MP and [{sup 11}C]l-MP respectively. Most of the striatal binding of [{sup 11}C]d-threo-MP was displaced by injection of nonradioactive MP demonstrating reversibility. Pretreatment with MP (0.5 mg/kg), GBR12909 (1.5 mg/kg) or {beta}-CIT (0.3 mg/kg) reduced ST/CB by about 60% and the ratios of distribution volumes at the steady-state for the triatum to cerebellum (DV{sub st/}DV{sub cb}) by about 50%. Pretreatment with tomoxetine (3.0 mg/kg) or citalopram (2.0 mg/kg), inhibitors of the norepinephrine and serotonin transporter, had no effect. Studies of [{sup 11}C]d-MP in the human brain showed highest uptake in basal ganglia with a half clearance time of about 60 minutes. Repeated studies in 6 normal human subjects showed differences in DV{sub st/}DV{sub cb} between -7% and 8%. MP pretreatment decreased BG but no cortical or cerebellar binding and reduced Bmax/Kd by 91%.

  19. Synthesis and Evaluation of [11C]LY2795050 as a Novel Kappa Opioid Receptor Antagonist Radiotracer for PET Imaging

    PubMed Central

    Zheng, Ming-Qiang; Nabulsi, Nabeel; Kim, Su Jin; Tomasi, Giampaolo; Lin, Shu-fei; Mitch, Charles; Quimby, Steven; Barth, Vanessa; Rash, Karen; Masters, John; Navarro, Antonio; Seest, Eric; Morris, Evan E.; Carson, Richard E.; Huang, Yiyun

    2013-01-01

    Kappa opioid receptors (KOR) are believed to be involved in the pathophysiology of depression, anxiety disorders, drug abuse and alcoholism. To date, only one tracer, the kappa opioid receptor agonist [11C]GR103545, has been reported to be able to image KOR in primates. The goal of the present study was to synthesize the selective KOR antagonist [11C]LY2795050 and evaluate its potential as a PET tracer to image KOR in vivo. METHODS In vitro binding affinity of LY2795050 was measured in radioligand competition binding assays. Ex vivo experiments were conducted using microdosing of the unlabelled ligand in Sprague-Dawley rats, as well as wild-type and KOR knock-out mice, to assess the ligand’s potential as a tracer candidate. Imaging experiments with [11C]LY2795050 in monkeys were carried out on the Focus-220 PET scanner with arterial blood input function measurement. Binding parameters were determined with kinetic modeling analysis. RESULTS LY2795050 displays full antagonist activity and high binding affinity and selectivity for KOR. Microdosing studies in rodents and ex vivo analysis of tissue concentrations with LC/MS/MS identified LY2795050 as an appropriate tracer candidate able to provide specific binding signals in vivo. [11C]LY2795050 was prepared in an average yield of 12% and >99% radiochemical purity. In rhesus monkeys, [11C]LY2795050 displayed a moderate rate of peripheral metabolism, with ∼40% of parent compound remaining at 30 min postinjection. In the brain, [11C]LY2795050 displayed fast uptake kinetics (regional activity peak times < 20 min) and an uptake pattern consistent with the distribution of KOR in primates. Pretreatment with naloxone (1 mg/kg, iv) resulted in a uniform distribution of radioactivity. Further, specific binding of [11C]LY2795050 was reduced by the selective KOR antagonist LY2456302 in a dose-dependent manner. CONCLUSION [11C]LY2795050 displayed favorable pharmacokinetic properties and binding profiles in vivo, and therefore

  20. Development of the brain's structural network efficiency in early adolescence: A longitudinal DTI twin study.

    PubMed

    Koenis, Marinka M G; Brouwer, Rachel M; van den Heuvel, Martijn P; Mandl, René C W; van Soelen, Inge L C; Kahn, René S; Boomsma, Dorret I; Hulshoff Pol, Hilleke E

    2015-12-01

    The brain is a network and our intelligence depends in part on the efficiency of this network. The network of adolescents differs from that of adults suggesting developmental changes. However, whether the network changes over time at the individual level and, if so, how this relates to intelligence, is unresolved in adolescence. In addition, the influence of genetic factors in the developing network is not known. Therefore, in a longitudinal study of 162 healthy adolescent twins and their siblings (mean age at baseline 9.9 [range 9.0-15.0] years), we mapped local and global structural network efficiency of cerebral fiber pathways (weighted with mean FA and streamline count) and assessed intelligence over a three-year interval. We find that the efficiency of the brain's structural network is highly heritable (locally up to 74%). FA-based local and global efficiency increases during early adolescence. Streamline count based local efficiency both increases and decreases, and global efficiency reorganizes to a net decrease. Local FA-based efficiency was correlated to IQ. Moreover, increases in FA-based network efficiency (global and local) and decreases in streamline count based local efficiency are related to increases in intellectual functioning. Individual changes in intelligence and local FA-based efficiency appear to go hand in hand in frontal and temporal areas. More widespread local decreases in streamline count based efficiency (frontal cingulate and occipital) are correlated with increases in intelligence. We conclude that the teenage brain is a network in progress in which individual differences in maturation relate to level of intellectual functioning. PMID:26368846

  1. The Efficiency and Budgeting of Public Hospitals: Case Study of Iran

    PubMed Central

    Yusefzadeh, Hasan; Ghaderi, Hossein; Bagherzade, Rafat; Barouni, Mohsen

    2013-01-01

    Background Hospitals are the most costly and important components of any health care system, so it is important to know their economic values, pay attention to their efficiency and consider factors affecting them. Objective The aim of this study was to assess the technical scale and economic efficiency of hospitals in the West Azerbaijan province of Iran, for which Data Envelopment Analysis (DEA) was used to propose a model for operational budgeting. Materials and Methods This study was a descriptive-analysis that was conducted in 2009 and had three inputs and two outputs. Deap2, 1 software was used for data analysis. Slack and radial movements and surplus of inputs were calculated for selected hospitals. Finally, a model was proposed for performance-based budgeting of hospitals and health sectors using the DEA technique. Results The average scores of technical efficiency, pure technical efficiency (managerial efficiency) and scale efficiency of hospitals were 0.584, 0.782 and 0.771, respectively. In other words the capacity of efficiency promotion in hospitals without any increase in costs and with the same amount of inputs was about 41.5%. Only four hospitals among all hospitals had the maximum level of technical efficiency. Moreover, surplus production factors were evident in these hospitals. Conclusions Reduction of surplus production factors through comprehensive planning based on the results of the Data Envelopment Analysis can play a major role in cost reduction of hospitals and health sectors. In hospitals with a technical efficiency score of less than one, the original and projected values of inputs were different; resulting in a surplus. Hence, these hospitals should reduce their values of inputs to achieve maximum efficiency and optimal performance. The results of this method was applied to hospitals a benchmark for making decisions about resource allocation; linking budgets to performance results; and controlling and improving hospitals performance

  2. Efficiency and quality of care in nursing homes: an Italian case study.

    PubMed

    Garavaglia, Giulia; Lettieri, Emanuele; Agasisti, Tommaso; Lopez, Silvano

    2011-03-01

    This study investigates efficiency and quality of care in nursing homes. By means of Data Envelopment Analysis (DEA), the efficiency of 40 nursing homes that deliver their services in the north-western area of the Lombardy Region was assessed over a 3-year period (2005-2007). Lombardy is a very peculiar setting, since it is the only Region in Italy where the healthcare industry is organised as a quasi-market, in which the public authority buys health and nursing services from independent providers-establishing a reimbursement system for this purpose. The analysis is conducted by generating bootstrapped DEA efficiency scores for each nursing home (stage one), then regressing those scores on explanatory variables (stage two). Our DEA model employed two input (i.e. costs for health and nursing services and costs for residential services) and three output variables (case mix, extra nursing hours and residential charges). In the second-stage analysis, Tobit regressions and the Kruskall-Wallis tests of hypothesis to the efficiency scores were applied to define what are the factors that affect efficiency: (a) the ownership (private nursing houses outperform their public counterparts); and (b) the capability to implement strategies for labour cost and nursing costs containment, since the efficiency heavily depends upon the alignment of the costs to the public reimbursement system. Lastly, even though the public institutions are less efficient than the private ones, the results suggest that public nursing homes are moving towards their private counterparts, and thus competition is benefiting efficiency. PMID:20922483

  3. Case Studies in the Field of Marketing Education: Learner Impact, Case Performance, and Cost Efficiency

    ERIC Educational Resources Information Center

    Spais, George S.

    2005-01-01

    The major objective of this study is to identify a methodology that will help educators in marketing to efficiently manage the design, impact, and cost of case studies. It is my intention is to examine the impact of case study characteristics in relation to the degree of learner involvement in the learning process. The author proposes that…

  4. The Effect of Curriculum for Developing Efficient Studying Skills on Academic Achievements and Studying Skills of Learners

    ERIC Educational Resources Information Center

    Demir, Semra; Kilinc, Mehmet; Dogan, Ali

    2012-01-01

    Purpose of this study is to examine the effect of "Development of Efficient Studying Skills Curriculum" on academic achievements and studying skills of 7th grade primary school students. In this study, pre-test post-test from experiment models and semi-experimental model with control group were preferred. The reason for the preference is…

  5. New Tabu Search based global optimization methods outline of algorithms and study of efficiency.

    PubMed

    Stepanenko, Svetlana; Engels, Bernd

    2008-04-15

    The study presents two new nonlinear global optimization routines; the Gradient Only Tabu Search (GOTS) and the Tabu Search with Powell's Algorithm (TSPA). They are based on the Tabu-Search strategy, which tries to determine the global minimum of a function by the steepest descent-mildest ascent strategy. The new algorithms are explained and their efficiency is compared with other approaches by determining the global minima of various well-known test functions with varying dimensionality. These tests show that for most tests the GOTS possesses a much faster convergence than global optimizer taken from the literature. The efficiency of the TSPA compares to the efficiency of genetic algorithms. PMID:17910004

  6. Structural efficiency studies of corrugated compression panels with curved caps and beaded webs

    NASA Technical Reports Server (NTRS)

    Davis, R. C.; Mills, C. T.; Prabhakaran, R.; Jackson, L. R.

    1984-01-01

    Curved cross-sectional elements are employed in structural concepts for minimum-mass compression panels. Corrugated panel concepts with curved caps and beaded webs are optimized by using a nonlinear mathematical programming procedure and a rigorous buckling analysis. These panel geometries are shown to have superior structural efficiencies compared with known concepts published in the literature. Fabrication of these efficient corrugation concepts became possible by advances made in the art of superplastically forming of metals. Results of the mass optimization studies of the concepts are presented as structural efficiency charts for axial compression.

  7. Evaluation of the anti-HER2 C6.5 diabody as a PET radiotracer to monitor HER2 status and predict response to trastuzumab treatment

    PubMed Central

    Reddy, Smitha; Shaller, Calvin C.; Doss, Mohan; Shchaveleva, Irina; Marks, James D.; Yu, Jian Q.; Robinson, Matthew K.

    2011-01-01

    Purpose The rapid tumor targeting and pharmacokinetic properties of engineered antibodies make them potentially suitable for use in imaging strategies to predict and monitor response to targeted therapies. This study aims to evaluate C6.5 diabody (C6.5db), a non-covalent anti-HER2 single chain-Fv dimer, as a radiotracer for predicting response to HER2-targeted therapies such as trastuzumab. Experimental Design Immunodeficient mice bearing established HER2-positive tumor xenografts were injected with radioiodinated C6.5db and imaged using PET/CT. Radiotracer biodistribution was quantified using biopsied tumor and normal tissues. Potential competition between trastuzumab and C6.5db was examined in vitro by flow cytometry and co-immunoprecipitations. Results Biodistribution analysis of mice bearing xenografts with varying HER2 density revealed that the tumor uptake of 125I-C6.5db correlates with HER2 tumor density. In vitro competition experiments suggest that the C6.5db targets an epitope on HER2 that is distinct from that bound by trastuzumab. Treatment of SK-OV-3-tumored mice with trastuzumab for 3 d caused a 42% (P=0.002) decrease in tumor uptake of 125I-C6.5db. This is consistent with a dramatic decrease in the tumor PET signal of 124I-C6.5db after trastuzumab treatment. Furthermore, BT-474-tumored mice showed a ∼60% decrease (P=0.0026) in C6.5db uptake after 6 d of trastuzumab treatment. Immunohistochemistry of excised xenograft sections and in vitro flow cytometry revealed that the decreased C6.5db uptake upon trastuzumab treatment is not associated with HER2 downregulation. Conclusions These studies suggest that 124I-C6.5db-based imaging can be used to evaluate HER2 levels as a predictor of respone to HER2-directed therapies. PMID:21177408

  8. A study of the efficiency of hydrogen liquefaction. [jet aircraft applications

    NASA Technical Reports Server (NTRS)

    Baker, C. R.; Shaner, R. L.

    1976-01-01

    The search for an environmentally acceptable fuel to eventually replace petroleum-based fuels for long-range jet aircraft has singled out liquid hydrogen as an outstanding candidate. Hydrogen liquefaction is discussed, along with the effect of several operating parameters on process efficiency. A feasible large-scale commercial hydrogen liquefaction facility based on the results of the efficiency study is described. Potential future improvements in hydrogen liquefaction are noted.

  9. Synthesis and characterization of (68)Ga-labeled curcumin and curcuminoid complexes as potential radiotracers for imaging of cancer and Alzheimer's disease.

    PubMed

    Asti, Mattia; Ferrari, Erika; Croci, Stefania; Atti, Giulia; Rubagotti, Sara; Iori, Michele; Capponi, Pier C; Zerbini, Alessandro; Saladini, Monica; Versari, Annibale

    2014-05-19

    Curcumin (CUR) and curcuminoids complexes labeled with fluorine-18 or technetium-99m have recently shown their potential as diagnostic tools for Alzheimer's disease. Gallium-68 is a positron-emitting, generator-produced radionuclide, and its properties can be exploited in situ in medical facilities without a cyclotron. Moreover, CUR showed a higher uptake in tumor cells compared to normal cells, suggesting potential diagnostic applications in this field. In spite of this, no studies using labeled CUR have been performed in this direction, so far. Herein, (68)Ga-labeled complexes with CUR and two curcuminoids, namely diacetyl-curcumin (DAC) and bis(dehydroxy)curcumin (bDHC), were synthesized and characterized by means of experimental and theoretical approaches. Moreover, a first evaluation of their affinity to synthetic β-amyloid fibrils and uptake by A549 lung cancer cells was performed to show the potential application of these new labeled curcuminoids in these diagnostic fields. The radiotracers were prepared by reacting (68)Ga(3+) obtained from a (68)Ge/(68)Ga generator with 1 mg/mL curcuminoids solutions. Reaction parameters (precursor amount, reaction temperature, and pH) were optimized to obtain high and reproducible radiochemical yield and purity. Stoichiometry and formation of the curcuminoid complexes were investigated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, NMR, ultraviolet-visible, and fluorescence spectroscopy on the equivalent (nat)Ga-curcuminoids (nat = natural) complexes, and their structure was computed by theoretical density functional theory calculations. The analyses evidenced that CUR, DAC, and bDHC were predominantly in the keto-enol form and attested to Ga(L)2(+) species formation. Identity of the (68)Ga(L)2(+) complexes was confirmed by coelution with the equivalent (nat)Ga(L)2(+) complexes in ultrahigh-performance liquid chromatography analyses.(68)Ga(CUR)2(+), (68)Ga(DAC)2(+), and (68)Ga(bDHC)2

  10. Integrated power sector efficiency analysis: A case study of Costa Rica

    SciTech Connect

    Waddle, D.B.; MacDonald, J.M.

    1990-03-01

    In an effort to analyze and document the potential for power sector efficiency improvements from generation to end-use, the Agency for International Development and the Government of Costa Rica are jointly conducting an integrated power sector efficiency analysis. Potential for energy and cost savings in power plants, transmission and distribution, and demand-side management programs are being evaluated. The product of this study will be an integrated investment plan for the Instituto Costarricense de Electricidad, incorporating both supply and demand side investment options. This paper presents the methodology employed in the study, as well as preliminary estimates of the results of the study. 14 refs., 2 figs., 5 tabs.

  11. Shuttle Ground Operations Efficiencies/Technologies (SGOE/T) study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Scholz, A. L.; Hart, M. T.; Lowry, D. J.

    1987-01-01

    Methods and technolgoy were defined to reduce the overall operations cost of a major space program. Space Shuttle processing at Kennedy Space Center (KSC) was designed as the working model that would be the source of the operational information. Methods of improving efficiency of ground operations were assessed and technology elements that could reduce cost identified. Emphasis is on: (1) specific technology items and (2) management approaches required to develop and support efficient ground operations. Prime study results are to be recommendations on how to achieve more efficient operations and identification of existing or new technology that would make vehicle processing in both the current program and future programs more efficient and, therefore, less costly.

  12. Human Resource Management Strategies and Teacher's Efficiency within Schools: A Co-Relational Study

    ERIC Educational Resources Information Center

    Hashmi, Kiran

    2014-01-01

    The aim of the paper is to study Human Resource Management and Development (HRMD) strategies and their effect on teachers' efficiency within the Catholic Board of Education (CBE) schools of Pakistan whose teachers are graduates in educational leadership courses from a private teacher education institutes in Karachi. The study endeavored to build a…

  13. A Fundamental Study for Efficient Implementaion of Online Collaborative Activities in Large-Scale Classes

    ERIC Educational Resources Information Center

    Matsuba, Ryuichi; Suzuki, Yusei; Kubota, Shin-Ichiro; Miyazaki, Makoto

    2015-01-01

    We study tactics for writing skills development through cross-disciplinary learning in online large-scale classes, and particularly are interested in implementation of online collaborative activities such as peer reviewing of writing. The goal of our study is to carry out collaborative works efficiently via online effectively in large-scale…

  14. Diffuse pulmonary uptake of bone-seeking radiotracer in bone scintigraphy of a rare case of pulmonary alveolar microlithiasis

    PubMed Central

    Fallahi, Babak; Ghafary, Bahar Moasses; Fard-Esfahani, Armaghan; Eftekhari, Mohammad

    2015-01-01

    Pulmonary alveolar microlithiasis (PAM) is a rare diffuse pulmonary disease representing microliths formed by deposition of calcium phosphonate in the alveolar airspaces. PAM is often diagnosed incidentally during chest X-ray imaging. Most of them are asymptomatic. We present a 39-year-old man referring for a bone scan due to a complaint of right leg pain. Bone scan showed diffuse uptake of bone-seeking radiotracer on both lung fields predominantly in basal regions. The bronchoalveolar lavage test confirmed the diagnosis of PAM. PMID:26170578

  15. Radiotracers in PETT: strategies for in vivo receptor activity, Schizophernia, and Alzheimer's Dementia studies

    SciTech Connect

    Wolf, A.P.

    1984-01-01

    Using /sup 18/F-spiperone, a one compartment system with a driving function as model, blocking agents such as butaclamol and ketanserin, assay of the live adult female baboon striatum over the 8 h period, and assay of the parent compound in plasma, it is apparent that residence times in the living tissue and those estimated from in vitro tritium data are at variance. Occupancy rises to a maximum for /sup 18/F benperidol and /sup 18/F haloperidol after approx. 25 minutes and for /sup 18/F spiperone after approx. 75 minutes, but the striatum concentration of /sup 18/F-spiperone and benperiodol remain nearly constant over an eight hour period whereas /sup 18/F haloperidol concentration starts falling almost immediately to half its maximum value at 8 hrs. The best fit to our current data gives a preliminary off rate constant of 0.0057 min/sup -1/.

  16. Radiotracers binding to estrogen receptors: I: tissue distribution of 17 alpha-ethynylestradiol and moxestrol in normal and tumor-bearing rats

    SciTech Connect

    Feenstra, A.; Nolten, G.M.; Vaalburg, W.; Reiffers, S.; Woldring, M.G.

    1982-07-01

    Ethynylestradiol and moxestrol can be labeled with /sup 11/C by introducing this positron emitter in the 17 alpha-ethynyl group. To investigate their potential as radiotracers binding to estrogen receptors, researchers studied the tissue distribution of tritiated ethynylestradiol and moxestrol, with specific activities of 57 Ci/mmol and 77-90 Ci/mmol, respectively, in the adult female rat. At 30 min after injection, both compounds showed specific uptake in the uterus (% dose/g): 2.52 for ethynylestradiol and of 2.43 for moxestrol. A decrease of the specific activity to 6-9 Ci/mmol resulted in uterine uptakes of 1.60 and 2.10 respectively, for ethynylestradiol and moxestrol, at 30 min. In the female rat bearing DMBA-induced mammary tumors, specific uptake was also measured in the tumors, although the values were only 25-30% of the uterine uptake. Moxestrol showed a greater uptake selectivity in the tumors compared with ethynylestradiol. From this study researchers conclude that ethynylestradiol and moxestrol have good potential as tracers binding to mammary tumors that contain estrogen receptors.

  17. On the efficiency of electrical submersible pumps equipped with variable frequency drives: A field study

    SciTech Connect

    Patterson, M.M.

    1996-02-01

    A field study was conducted on 18 electrical-submersible-pump- (ESP-) equipped wells operating in the Williston basin. Fifteen of these wells were run with variable frequency drives (VFD`s). The purpose of the study was to determine the efficiency and operating characteristics of ESP`s operating with VFD`s and compare them to those without. Voltage, current, power, and frequency were measured at the drive input, the drive output, and ESP input. Production data were recorded and power and efficiency were calculated at all measurement locations and compared to published data.

  18. Product lifetime, energy efficiency and climate change: A case study of air conditioners in Japan.

    PubMed

    Nishijima, Daisuke

    2016-10-01

    This study proposed a modelling technique for estimating life-cycle CO2 emissions of durable goods by considering changes in product lifetime and energy efficiency. The stock and flow of durable goods was modelled by Weibull lifetime distributions and the trend in annual energy efficiency (i.e., annual electricity consumption) of an "average" durable good was formulated as a reverse logistic curve including a technologically critical value (i.e., limit energy efficiency) with respect to time. I found that when the average product lifetime is reduced, there is a trade-off between the reduction in emissions during product use (use phase), due to the additional purchases of new, more energy-efficient air conditioners, and the increase in emissions arising from the additional production of new air conditioners stimulated by the reduction of the average product lifetime. A scenario analysis focused on residential air conditioners in Japan during 1972-2013 showed that for a reduction of average lifetime of 1 year, if the air conditioner energy efficiency limit can be improved by 1.4% from the estimated current efficiency level, then CO2 emissions can be reduced by approximately the same amount as for an extension of average product lifetime of 1 year. PMID:27423771

  19. Variation in efficiency of parallel algorithms. [for study of stiffness matrices in planar trusses

    NASA Technical Reports Server (NTRS)

    Hayashi, A.; Melosh, R. J.; Utku, S.; Salama, M.

    1985-01-01

    The present study has the objective to investigate some iterative parallel-processor linear equation solving algorithms with respect to efficiency for analyses of typical linear engineering systems. Attention is given to a set of n linear equations, Ku = p, where K = an n x n positive definite, sparsely populated, symmetric matrix, u = an n x 1 vector of unknown responses, and p = an n x 1 vector of prescribed constants. This study is concerned with a hybrid method in which iteration is used to solve the problem, while a direct method is used on the local processor level. Variations in the efficiency of parallel algorithms are explored. Measures of the efficiency are based on computer experiments regarding the algorithms. For all the algorithms, the wall clock time is found to decrease as the number of processors increases.

  20. Radiosynthesis of a dopamine receptor-binding radiotracer for positron emission tomography: 3-N-(C-11-methyl)-methyl-spiperone

    SciTech Connect

    Ravert, H.T.; Burns, H.D.; Dannals, R.F.; Langstrom, B.; Duelfer, T.; Wilson, A.A.; Zemyan, S.E.; Wagner, H.N. Jr.

    1984-01-01

    Dopamine receptors appear to be involved with abnormalities related to disorders such as Parkinson's disease and schizophrenia. Spiperone is an extremely potent neuroleptic which binds with high affinity to dopamine receptors. Based on in vitro binding studies, the authors selected 3-N-methylspiperone, a derivative of spiperone which has similar binding characteristics, for radiolabeling. C-11 Methyl iodide was prepared from C-11 carbon dioxide and bubbled through a methylene chloride solution of spiperone. Aqueous tetrabutylammonium hydroxide was added with mixing by sonication. The product was isolated by preparative reverse phase high performance liquid chromatography (HPLC) and analyzed for radiochemical purity by analytical C-18 HPLC. Further refinement of the radiochemical synthesis has reduced the time of preparation from an average of 80 minutes to approximately 30 minutes. As many as 5 production runs have been carried out per day. Three are performed routinely due to the shortened synthesis time and the judicious use of remote handling. Automation of the process is now in progress. In 108 consecutive production runs of this radiotracer, the average radiochemical yield has been 35% with an average synthesis time of 36 minutes and the average specific activity of 294 mCi/..mu..mole E.O.S.

  1. Affinity of (nat/68)Ga-Labelled Curcumin and Curcuminoid Complexes for β-Amyloid Plaques: Towards the Development of New Metal-Curcumin Based Radiotracers.

    PubMed

    Rubagotti, Sara; Croci, Stefania; Ferrari, Erika; Iori, Michele; Capponi, Pier C; Lorenzini, Luca; Calzà, Laura; Versari, Annibale; Asti, Mattia

    2016-01-01

    Curcumin derivatives labelled with fluorine-18 or technetium-99m have recently shown their potential as diagnostic tools for Alzheimer's disease. Nevertheless, no study by exploiting the labelling with gallium-68 has been performed so far, in spite of its suitable properties (positron emitter, generator produced radionuclide). Herein, an evaluation of the affinity for synthetic β-amyloid fibrils and for amyloid plaques of three (nat/68)Ga-labelled curcumin analogues, namely curcumin curcumin (CUR), bis-dehydroxy-curcumin (bDHC) and diacetyl-curcumin (DAC), was performed. Affinity and specificity were tested in vitro on amyloid synthetic fibrils by using gallium-68 labelled compounds. Post-mortem brain cryosections from Tg2576 mice were used for the ex vivo visualization of amyloid plaques. The affinity of (68)Ga(CUR)₂⁺, (68)Ga(DAC)₂⁺, and (68)Ga(bDHC)₂⁺ for synthetic β-amyloid fibrils was moderate and their uptake could be observed in vitro. On the other hand, amyloid plaques could not be visualized on brain sections of Tg2576 mice after injection, probably due to the low stability of the complexes in vivo and of a hampered passage through the blood-brain barrier. Like curcumin, all (nat/68)Ga-curcuminoid complexes maintain a high affinity for β-amyloid plaques. However, structural modifications are still needed to improve their applicability as radiotracers in vivo. PMID:27608011

  2. Financial Analysis of Incentive Mechanisms to Promote Energy Efficiency: Case Study of a Prototypical Southwest Utility

    SciTech Connect

    Cappers, Peter; Goldman, Charles; Chait, Michele; Edgar, George; Schlegel, Jeff; Shirley, Wayne

    2009-03-04

    Many state regulatory commissions and policymakers want utilities to aggressively pursue energy efficiency as a strategy to mitigate demand and energy growth, diversify the resource mix, and provide an alternative to building new, costly generation. However, as the National Action Plan for Energy Efficiency (NAPEE 2007) points out, many utilities continue to shy away from aggressively expanding their energy efficiency efforts when their shareholder's fundamental financial interests are placed at risk by doing so. Thus, there is increased interest in developing effective ratemaking and policy approaches that address utility disincentives to pursue energy efficiency or lack of incentives for more aggressive energy efficiency efforts. New regulatory initiatives to promote increased utility energy efficiency efforts also affect the interests of consumers. Ratepayers and their advocates are concerned with issues of fairness, impacts on rates, and total consumer costs. From the perspective of energy efficiency advocates, the quid pro quo for utility shareholder incentives is the obligation to acquire all, or nearly all, achievable cost-effective energy efficiency. A key issue for state regulators and policymakers is how to maximize the cost-effective energy efficiency savings attained while achieving an equitable sharing of benefits, costs and risks among the various stakeholders. In this study, we modeled a prototypical vertically-integrated electric investor-owned utility in the southwestern US that is considering implementing several energy efficiency portfolios. We analyze the impact of these energy efficiency portfolios on utility shareholders and ratepayers as well as the incremental effect on each party when lost fixed cost recovery and/or utility shareholder incentive mechanisms are implemented. A primary goal of our quantitative modeling is to provide regulators and policymakers with an analytic framework and tools that assess the financial impacts of

  3. ACEEE 1990 summer study on energy efficiency in buildings: Proceedings. Subject and Author Index

    SciTech Connect

    Not Available

    1990-12-31

    The sixth Summer Study on Energy Efficiency in Buildings, a biennial conference, attracts an international and interdisciplinary audience from utilities, public-interest groups, public utility commissions, government agencies, universities, research institutions, and appliance manufacturers, as well as builders, architects, and engineers. During this year`s week-long conference, participants exchange information and share ideas on how to improve the efficient use of energy in buildings. The 1990 Summer Study focuses on what we know now about energy efficiency in buildings and where we should be headed. Topics examined include new technologies for residential, commercial, and industrial buildings; improved appliance and equipment efficiency; cost-effective building retrofits; design and implementation of government programs; marketing demand-side programs; least-cost utility planning; and other utility issues. This year, because of the increased interest in such environmental issues as global warming, acid rain, and ozone depletion, recently completed research on energy efficiency and the environment is also presented for discussion. These individual papers are processed separately for the Energy Data Base. This current volume includes author and subject indexes to these papers.

  4. Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique.

    PubMed

    Pant, H J; Sharma, V K; Shenoy, K T; Sreenivas, T

    2015-03-01

    An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40-60MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation. PMID:25528019

  5. Novel Histone Deacetylase Class IIa Selective Substrate Radiotracers for PET Imaging of Epigenetic Regulation in the Brain

    PubMed Central

    Bonomi, Robin; Mukhopadhyay, Uday; Shavrin, Aleksandr; Yeh, Hsien-Hsien; Majhi, Anjoy; Dewage, Sajeewa W.; Najjar, Amer; Lu, Xin; Cisneros, G. Andrés; Tong, William P.; Alauddin, Mian M.; Liu, Ren-Shuan; Mangner, Thomas J.; Turkman, Nashaat; Gelovani, Juri G.

    2015-01-01

    Histone deacetylases (HDAC’s) became increasingly important targets for therapy of various diseases, resulting in a pressing need to develop HDAC class- and isoform-selective inhibitors. Class IIa deacetylases possess only minimal deacetylase activity against acetylated histones, but have several other client proteins as substrates through which they participate in epigenetic regulation. Herein, we report the radiosyntheses of the second generation of HDAC class IIa–specific radiotracers: 6-(di-fluoroacetamido)-1-hexanoicanilide (DFAHA) and 6-(tri-fluoroacetamido)-1-hexanoicanilide ([18F]-TFAHA). The selectivity of these radiotracer substrates to HDAC class IIa enzymes was assessed in vitro, in a panel of recombinant HDACs, and in vivo using PET/CT imaging in rats. [18F]TFAHA showed significantly higher selectivity for HDAC class IIa enzymes, as compared to [18F]DFAHA and previously reported [18F]FAHA. PET imaging with [18F]TFAHA can be used to visualize and quantify spatial distribution and magnitude of HDAC class IIa expression-activity in different organs and tissues in vivo. Furthermore, PET imaging with [18F]TFAHA may advance the understanding of HDACs class IIa mediated epigenetic regulation of normal and pathophysiological processes, and facilitate the development of novel HDAC class IIa-specific inhibitors for therapy of different diseases. PMID:26244761

  6. Study on Providing Professors with Efficient Service Based on Time Management Strategy

    ERIC Educational Resources Information Center

    Li, Chunlin; Liu, Mengchao; Wang, Yining

    2016-01-01

    Time management is the study to use time scientifically by deploying skills, techniques and means, and maximizing time value to help individuals or organizations efficiently complete tasks and achieve goals. University professor as a body is an important force in teaching and research. In order to ensure high-quality teaching, productive research,…

  7. Expectation-Based Efficiency and Quality Improvements in Research Administration: Multi-Institutional Case Studies

    ERIC Educational Resources Information Center

    Saha, Dhanonjoy C.; Ahmed, Abrar; Hanumandla, Shailaja

    2011-01-01

    Conventional wisdom may support the presumed notion that higher expectations increase efficiency and improve quality. However, this claim may only be validated when workers are equipped with appropriate tools, training, and a conducive work environment. This study implements various interventions, observes outcomes, and analyzes data collected in…

  8. An Action Research Study of Effective and Efficient Rehearsals in a Grade 8 Band Setting

    ERIC Educational Resources Information Center

    Ferley, Maureen

    2007-01-01

    Involving 28 grade eight students, this action research study examined strategies that lead to effective and efficient band rehearsals at the junior high level. Data was gathered concerning the proportion of instructional time spent on teaching concepts and skills, on active music making, and on classroom management. From this, and a review of the…

  9. Tracking Our Success: How TAFE Institutes Measure Their Effectiveness and Efficiency--Case Studies. Support Document

    ERIC Educational Resources Information Center

    Misko, Josie; Wynes, Sian Halliday

    2009-01-01

    This report is the support document to "Tracking Our Success: How TAFE Institutes Measure Their Effectiveness and Efficiency". It comprises reports on each of the nine technical and further education (TAFE) institutes that have taken part in the study. Information was collected via in-depth interviews with chief executive officers and their senior…

  10. A Study on the Learning Efficiency of Multimedia-Presented, Computer-Based Science Information

    ERIC Educational Resources Information Center

    Guan, Ying-Hua

    2009-01-01

    This study investigated the effects of multimedia presentations on the efficiency of learning scientific information (i.e. information on basic anatomy of human brains and their functions, the definition of cognitive psychology, and the structure of human memory). Experiment 1 investigated whether the modality effect could be observed when the…

  11. Greens, suits, and bureaucrats: A sociological study of dynamic organizational relationships in energy efficient appliance policy

    NASA Astrophysics Data System (ADS)

    Shwom-Evelich, Rachael Leah

    In this dissertation I develop an approach to understanding dynamic organizational relations and the processes of environmental degradation and reform. To do this, I draw on environmental and organizational sociology to inform an empirical study of interorganizational relationships in defining and promoting energy efficient appliances in the United States (US). The dissertation follows a three paper approach which involves (a) an overall introduction to the substantive issue of appliance energy efficiency in the US; (b) producing three separate and stand alone articles of publishable quality to be submitted to professional journals; and (c) an overall conclusion. The three articles are as follows: (1) a synthetic literature review identifying five lessons that organizational sociology and environmental sociology can learn from each other to advance our sociological understanding of organizations, energy issues, and climate change (2) a qualitative case study of the changing relationships between business, government and environmental and energy advocacy organizations around mandatory appliance efficiency standards supporting the development of a context-dependent theory of ecological modernization and treadmill of production theories in environmental sociology and (3) a network analysis of public government, business and energy efficiency advocate's interorganizational relationships and its influence on subsequent organizational behaviors in the appliance energy efficiency field. The second and third articles are based on extensive archival research on organizational negotiations of public record over defining energy efficient appliances in both regulatory and voluntary settings. Finally I will provide an overall conclusion that brings together the most significant findings of each individual article in anticipation of a synthetic approach to the study of organizations in environmental reform.

  12. Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 5: OEPSS final briefing for first year study

    NASA Technical Reports Server (NTRS)

    Wong, George S.; Waldrop, Glen S.

    1990-01-01

    This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) Program, the results of the Operationally Efficient Propulsion System Study (OEPSS) were organized into a series of OEPSS Data Books. This volume contains the final briefing on the OEPSS first-year effort. This briefing was presented to MSFC as part of an effort to promote greater interaction between the design community and the launch site operator.

  13. The hidden regional costs of improving irrigation efficiency: a case study from India

    NASA Astrophysics Data System (ADS)

    Grogan, D. S.; Frolking, S. E.; Lammers, R. B.; Wisser, D.; Proussevitch, A. A.; Glidden, S.

    2013-12-01

    Indian agriculture depends heavily on groundwater pumping. These water withdrawals are not all consumed directly by the crops they irrigate; estimated irrigation inefficiencies indicate that two thirds of irrigation water withdrawals in India are 'lost'. Withdrawals lost through leaky canals and flood irrigation systems become runoff and re-enter the surface water system. This mechanism causes irrigation inefficiencies to re-distribute water across basins, and can significantly alter the amount of surface water available both locally and downstream. In this study we used a gridded water balance model to track the path of groundwater from its pumping location, through irrigation systems, and to its downstream consumption or discharge from river mouths. We find that nearly half of all groundwater pumped at rates higher than recharge are re-used downstream. Furthermore, increasing the efficiency of irrigation systems has the potential to decrease surface water levels downstream. We used the water balance model to simulate scenarios of increased irrigation efficiency and find that doubling efficiency does not reduce India's dependence on pumping deep groundwater by half as would be expected from standard measures of irrigation efficiency, but rather by only 38%. Increasing irrigation efficiency to 100% (i.e., no irrigation water losses) causes a decrease in modeled river discharge in both the Indus and the Ganges. The water balance model can also simulate scenarios in which groundwater pumping is limited to recharge rates. In this case, increasing irrigation efficiency to 100% results in a decrease in available surface water across large regions of eastern India, revealing the region's dependence on surface water that was originally sourced from deep groundwater pumping upstream. These results have two important implications. First, they raise questions about the strategy of increasing irrigation efficiency as a strategy for reducing water stress. Second, they show

  14. Comparative study of fusion algorithms and implementation of new efficient solution

    NASA Astrophysics Data System (ADS)

    Besrour, Amine; Snoussi, Hichem; Siala, Mohamed; Abdelkefi, Fatma

    2014-05-01

    High Dynamic Range (HDR) imaging has been the subject of significant researches over the past years, the goal of acquiring the best cinema-quality HDR images of fast-moving scenes using an efficient merging algorithm has not yet been achieved. In fact, through the years, many efficient algorithms have been implemented and developed. However, they are not yet efficient since they don't treat all the situations and they have not enough speed to ensure fast HDR image reconstitution. In this paper, we will present a full comparative analyze and study of the available fusion algorithms. Also, we will implement our personal algorithm which can be more optimized and faster than the existed ones. We will also present our investigated algorithm that has the advantage to be more optimized than the existing ones. This merging algorithm is related to our hardware solution allowing us to obtain four pictures with different exposures.

  15. A precise study on effects that trigger alkaline hemicellulose extraction efficiency.

    PubMed

    Hutterer, Christian; Schild, Gabriele; Potthast, Antje

    2016-08-01

    The conversion of paper-grade pulps into dissolving pulps requires efficient strategies and process steps to remove low-molecular noncellulosic macromolecules generally known as hemicelluloses. Current strategies include alkaline extractions and enzymatic treatments. This study focused on the evaluation of extraction efficiencies in alkaline extractions of three economically interesting hardwood species: beech (Fagus sylvatica), birch (Betula papyrifera), and eucalyptus (Eucalyptus globulus). Substrate pulps were subjected to alkaline treatments at different temperatures and alkalinities using white liquor as the alkali source, followed by analyses of both pulps and hemicellulose-containing extraction lyes. The extracted hardwood xylans have strong potential as an ingredient in the food and pharmaceutical industries. Subsequent analyses revealed strong dependencies of the extraction efficiencies and molar mass distributions of hemicelluloses on the process variables of temperature and effective alkalinity. The hemicellulose content of the initial pulps, the hardwood species, and the type of applied base played minor roles. PMID:27163434

  16. Study on deposition rate and laser energy efficiency of Laser-Induction Hybrid Cladding

    NASA Astrophysics Data System (ADS)

    Wang, DengZhi; Hu, QianWu; Zheng, YinLan; Xie, Yong; Zeng, XiaoYan

    2016-03-01

    Laser-Induction Hybrid Cladding (LIHC) was introduced to prepare metal silicide based composite coatings, and influence of different factors such as laser type, laser power, laser scan speed and induction preheating temperature on the coating deposition rate and laser energy efficiency was studied systematically. Compared with conventional CO2 laser cladding, fiber laser-induction hybrid cladding improves the coating deposition rate and laser energy efficiency by 3.7 times. When a fiber laser with laser power of 4 kW was combined with an induction preheating temperature of 850 °C, the maximum coating deposition rate and maximum laser energy efficiency reaches 71 g/min and 64% respectively.

  17. Simulation Study of Current Drive Efficiency for KSTAR 5 GHz LHCD

    SciTech Connect

    Aria, A. K.; Bae, Y. S.; Yang, H. L.; Kwon, M.; Do, H. J.; Namkung, W.; Cho, M. H.; Park, H.

    2011-12-23

    Theoretical 5 GHz lower hybrid current drive (LHCD) efficiency using power spectrum given by 0-D Brambilla code and Lower Hybrid Simulation Code (LSC) have been studied for KSTAR. In LSC simulation, RF-driven current and current drive efficiency has been found to be deeply dependent on the profiles of the plasma density and temperature as well as on current profile in order to obtain hollow current profile favorable for advance tokamak operation mode and steady state operation. The peaked density and broad temperature profile control has been found to be efficient in current drive with maximum RF-driven current larger than 400 kA/MW with very high efficiency when the peak plasma density is ranged from 0.2 to 2.0x1020 m-3, and the peak electron temperature range of 2-20 keV together with toroidal field 2-3.5 T and Ip = 0.5-2 MA. The on-/off-axis current profile controllability is also investigated through parametric scan, and small negative magnetic shear is seen at the narrow region of the off-axis for very high temperature regime and for high BT and I{sub p}. In order to achieve the same for lower temperature regime Ip has to be lower and also for higher LH-power compromising with CD efficiency in this case.

  18. Eco-efficiency in extended supply chains: a case study of furniture production.

    PubMed

    Michelsen, Ottar; Fet, Annik Magerholm; Dahlsrud, Alexander

    2006-05-01

    This paper presents a methodology about how eco-efficiency in extended supply chains (ESCs) can be understood and measured. The extended supply chain includes all processes in the life cycle of a product and the eco-efficiency is measured as the relative environmental and value performance in one ESC compared to other ESCs. The paper is based on a case study of furniture production in Norway. Nine different environmental performance indicators are identified. These are based on suggestions from the World Business Council for Sustainable Development and additional indicators that are shown to have significant impacts in the life cycle of the products. Value performance is measured as inverse life cycle costs. The eco-efficiency for six different chair models is calculated and the relative values are shown graphically in XY-diagrams. This provides information about the relative performance of the products, which is valuable in green procurement processes. The same method is also used for analysing changes in eco-efficiency when possible alterations in the ESC are introduced. Here, it is shown that a small and realistic change of end-of-life treatment significantly changes the eco-efficiency of a product. PMID:16253417

  19. An experimental study on the efficiency of transpiration cooling in laminar and turbulent hypersonic flows

    NASA Astrophysics Data System (ADS)

    Gülhan, A.; Braun, S.

    2011-03-01

    An experimental study on the efficiency of transpiration cooling in hypersonic laminar and turbulent flow regimes is carried out in the Hypersonic Windtunnel Cologne with a focus on the aerothermal problems downstream of the cooled model part. The model is made of a material of low thermal conductivity (PEEK) with an integrated probe of a porous material. The experimental setup allows the direct comparison of the thermal behavior of transpiration cooling to a well-defined and radiatively cooled reference surface. Experiments are performed at Mach number of 6 and two different Reynolds numbers. Air, argon and helium are used as coolants at various flow rates, in order to identify the influence of coolant medium on cooling efficiency. The cooling efficiency of air and argon is comparable. Helium provides significantly higher cooling efficiency at the same blowing ratio, i.e. same coolant mass flow rate. The experimental data shows that the efficiency of the transpiration cooling in turbulent flows is much lower than in laminar flow.

  20. Studies of micromorphology and current efficiency of zinc electrodeposited from flowing chloride electrolytes

    SciTech Connect

    Mc Vay, L.; Muller, R.H.; Tobias, C.W.

    1986-05-01

    Results of a study of the micromorphology and current efficiency of zinc electrodeposited from flowing, acidic chloride solutions are reported. The effects of six variables were examined: flow rate, current density, zinc and hydrogen ion concentration, concentrations of nickel, iron and cadmium impurity ions, and the nature of the substrate. The development of micromorphology was studied in-situ by means of videomicrography and ex-situ by means of scanning electron microscopy. This investigation focused on the formation of grooved deposits, which are found under a wide range of deposition conditions. The major conclusions of this study are: the most important variable determining whether grooved deposits form is the interfacial concentration; large protrusions orient themselves parallel to the flow direction with the orientation starting upstream and progressing downstream; large protrusions become ridges due to growth of the highest current density portions of the electrode under mass transport control. The current efficiency was measured using EDTA titration and weight measurements. The fraction of the current taken by zinc deposition increased with zinc concentration, ranging up to 100%, and decreased with pH. The efficiency of zinc deposition was affected by the flow rate and the substrate employed. Impurities lowered the current efficiency.

  1. Analytical and experimental study of structurally efficient composite hat-stiffened panels loaded in axial compression

    NASA Technical Reports Server (NTRS)

    Williams, J. G.; Mikulus, M. M., Jr.

    1976-01-01

    Structural efficiency studies were made to determine the weight saving potential of graphite/epoxy composite structures for compression panel applications. Minimum weight hat-stiffened and open corrugation configurations were synthesized using a nonlinear mathematical programming technique. Selected configurations were built and tested to study local and Euler buckling characteristics. Test results for 23 panels critical in local buckling and six panels critical in Euler buckling are compared with analytical results obtained using the BUCLASP-2 branched plate buckling program. A weight efficiency comparison is made between composite and aluminum compression panels using metal test data generated by the NACA. Theoretical studies indicate that potential weight savings of up to 50% are possible for composite hat-stiffened panels when compared with similar aluminum designs. Weight savings of 32% to 42% were experimentally achieved. Experience suggests that most of the theoretical weight saving potential is available if design deficiencies are eliminated and strict fabrication control is exercised.

  2. Home energy efficiency and radon related risk of lung cancer: modelling study

    PubMed Central

    Milner, James; Shrubsole, Clive; Das, Payel; Jones, Benjamin; Ridley, Ian; Chalabi, Zaid; Hamilton, Ian; Armstrong, Ben; Davies, Michael

    2014-01-01

    Objective To investigate the effect of reducing home ventilation as part of household energy efficiency measures on deaths from radon related lung cancer. Design Modelling study. Setting England. Intervention Home energy efficiency interventions, motivated in part by targets for reducing greenhouse gases, which entail reduction in uncontrolled ventilation in keeping with good practice guidance. Main outcome measures Modelled current and future distributions of indoor radon levels for the English housing stock and associated changes in life years due to lung cancer mortality, estimated using life tables. Results Increasing the air tightness of dwellings (without compensatory purpose-provided ventilation) increased mean indoor radon concentrations by an estimated 56.6%, from 21.2 becquerels per cubic metre (Bq/m3) to 33.2 Bq/m3. After the lag in lung cancer onset, this would result in an additional annual burden of 4700 life years lost and (at peak) 278 deaths. The increases in radon levels for the millions of homes that would contribute most of the additional burden are below the threshold at which radon remediation measures are cost effective. Fitting extraction fans and trickle ventilators to restore ventilation will help offset the additional burden but only if the ventilation related energy efficiency gains are lost. Mechanical ventilation systems with heat recovery may lower radon levels and the risk of cancer while maintaining the advantage of energy efficiency for the most airtight dwellings but there is potential for a major adverse impact on health if such systems fail. Conclusion Unless specific remediation is used, reducing the ventilation of dwellings will improve energy efficiency only at the expense of population wide adverse impact on indoor exposure to radon and risk of lung cancer. The implications of this and other consequences of changes to ventilation need to be carefully evaluated to ensure that the desirable health and environmental benefits of

  3. A Radiotracer Strategy to Quantify PARP-1 Expression In Vivo Provides a Biomarker That Can Enable Patient Selection for PARP Inhibitor Therapy.

    PubMed

    Makvandi, Mehran; Xu, Kuiying; Lieberman, Brian P; Anderson, Redmond-Craig; Effron, Samuel Sander; Winters, Harrison D; Zeng, Chenbo; McDonald, Elizabeth S; Pryma, Daniel A; Greenberg, Roger A; Mach, Robert H

    2016-08-01

    Despite the availability of PARP inhibitors for cancer therapy, a biomarker to clearly stratify patients for selection of this treatment remains lacking. Here we describe a radiotracer-based method that addresses this issue, using the novel compound [(125)I] KX1: as a PARP-1-selective radiotracer that can accurately measure PARP-1 expression in vitro and in vivo The pharmacologic properties of the PARP radiotracer [(125)I] KX1: was characterized in multiple cell lines where single-agent sensitivity was correlated with [(125)I] KX1: binding to PARP-1. In vivo evaluation of [(125)I] KX1: verified in vitro results, validating PARP radiotracers to define PARP-1 enzyme expression as an in vivo biomarker. Notably, PARP-1 expression as quantified by [(125)I] KX1: correlated positively with the cytotoxic sensitivity of cell lines evaluated with PARP inhibitors. Overall, our results defined a novel technology with the potential to serve as a companion diagnostic to identify patients most likely to respond therapeutically to a PARP inhibitor. Cancer Res; 76(15); 4516-24. ©2016 AACR. PMID:27261505

  4. Synthesis and evaluation of an (125)I-labeled azide prosthetic group for efficient and bioorthogonal radiolabeling of cyclooctyne-group containing molecules using copper-free click reaction.

    PubMed

    Choi, Mi Hee; Shim, Ha Eun; Nam, You Ree; Kim, Hye Rim; Kang, Jung Ae; Lee, Dong-Eun; Park, Sang Hyun; Choi, Dae Seong; Jang, Beom-Su; Jeon, Jongho

    2016-02-01

    Herein we report the radiosynthesis of a pyridine derived azide prosthetic group for iodine radioisotope labeling of dibenzocyclooctyne (DBCO) conjugated molecules. The radiolabeling of the stannylated precursor 2 was conducted using [(125)I]NaI and chloramine-T to give (125)I-labeled azide ([(125)I]1) with high radiochemical yield (72±8%, n=4) and radiochemical purity (>99%). Using (125)I-labeled azide ([(125)I]1), cyclic RGD peptide and near infrared fluorescent molecule were efficiently labeled with modest to good radiochemical yields. The biodistribution study and SPECT/CT images showed that [(125)I]1 underwent rapid renal clearance. These results clearly demonstrated that [(125)I]1 could be used as an useful radiotracer for in vivo pre-targeted imaging as well as efficient in vitro radiolabeling of DBCO containing molecules. PMID:26748695

  5. Pollutant emissions and energy efficiency of Chinese gasifier cooking stoves and implications for future intervention studies.

    PubMed

    Carter, Ellison M; Shan, Ming; Yang, Xudong; Li, Jiarong; Baumgartner, Jill

    2014-06-01

    Household air pollution from solid fuel combustion is the leading environmental health risk factor globally. In China, almost half of all homes use solid fuel to meet their household energy demands. Gasifier cookstoves offer a potentially affordable, efficient, and low-polluting alternative to current solid fuel combustion technology, but pollutant emissions and energy efficiency performance of this class of stoves are poorly characterized. In this study, four Chinese gasifier cookstoves were evaluated for their pollutant emissions and efficiency using the internationally recognized water boiling test (WBT), version 4.1.2. WBT performance indicators included PM2.5, CO, and CO2 emissions and overall thermal efficiency. Laboratory investigation also included evaluation of pollutant emissions (PM2.5 and CO) under stove operating conditions designed to simulate common Chinese cooking practices. High power average overall thermal efficiencies ranged from 22 to 33%. High power average PM2.5 emissions ranged from 120 to 430 mg/MJ of useful energy, and CO emissions ranged from 1 to 30 g/MJ of useful energy. Compared with several widely disseminated "improved" cookstoves selected from the literature, on average, the four Chinese gasifier cookstoves had lower PM2.5 emissions and higher CO emissions. The recent International Organization for Standardization (ISO) International Workshop Agreement on tiered cookstove ranking was developed to help classify stove performance and identify the best-performing stoves. The results from this study highlight potential ways to further improve this approach. Medium power stove operation emitted nearly twice as much PM2.5 as was emitted during high power stove operation, and the lighting phase of a cooking event contributed 45% and 34% of total PM2.5 emissions (combined lighting and cooking). Future approaches to laboratory-based testing of advanced cookstoves could improve to include greater differentiation between different modes of

  6. Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 3: Operations technology

    NASA Technical Reports Server (NTRS)

    Vilja, John O.

    1990-01-01

    The study was initiated to identify operational problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) program, the results of the OEPSS study were organized into a series of OEPSS Data Books. This volume describes operations technologies that will enhance operational efficiency of propulsion systems. A total of 15 operations technologies were identified that will eliminate or mitigate operations problems described in Volume 2. A recommended development plan is presented for eight promising technologies that will simplify the propulsion system and reduce operational requirements.

  7. Ion generation and CPC detection efficiency studies in sub 3-nm size range

    SciTech Connect

    Kangasluoma, J.; Junninen, H.; Sipilae, M.; Kulmala, M.; Petaejae, T.; Lehtipalo, K.; Mikkilae, J.; Vanhanen, J.; Attoui, M.; Worsnop, D.

    2013-05-24

    We studied the chemical composition of commonly used condensation particle counter calibration ions with a mass spectrometer and found that in our calibration setup the negatively charged ammonium sulphate, sodium chloride and tungsten oxide are the least contaminated whereas silver on both positive and negative and the three mentioned earlier in positive mode are contaminated with organics. We report cut-off diameters for Airmodus Particle Size Magnifier (PSM) 1.1, 1.3, 1.4, 1.6 and 1.6-1.8 nm for negative sodium chloride, ammonium sulphate, tungsten oxide, silver and positive organics, respectively. To study the effect of sample relative humidity on detection efficiency of the PSM we used different humidities in the differential mobility analyzer sheath flow and found that with increasing relative humidity also the detection efficiency of the PSM increases.

  8. Experimental Study for High Efficiency on R410A Scroll Compressor

    NASA Astrophysics Data System (ADS)

    Sawai, Kiyoshi; Hiwata, Akira; Sakuda, Atsushi; Iida, Noboru; Morimoto, Takashi; Ishii, Noriaki

    In scroll compressors, oil injection to the compression chambers reduces refrigerant leakage loss in the compression process, while causes the heating loss in the suction process. In the previous experimental study where the relationship between the oil flow rate to the compression chambers and the compressor performance was investigated, we reported that the present R410A scroll compressor can be operated at higher efficiency as decreasing the oil flow rate. Based on this experimental result, we adopted a new oil supply device, which is the intermittent oil supply mechanism installed in the orbiting scroll, thus improving the efficiency. We studied theoretical oil flow rate of this new device, and addressing that this mechanism has excellent characteristics in oil flow control. Then we provided appropriate oil flow rate for the compression chambers with this new oil supply device, thus achieving higher performance on the R410A scroll compressor.

  9. A Study on Market Efficiency of Selected Commodity Derivatives Traded on NCDEX During 2011

    NASA Astrophysics Data System (ADS)

    Sajipriya, N.

    2012-10-01

    The study aims at testing the weak form of Efficient Market Hypothesis in the context of an emerging commodity market - National Commodity Derivatives Exchange (NCDEX), which is considered as the prime commodity derivatives market in India. The study considered daily spot and futures prices of five selected commodities traded on NCDEX over 12 month period (the futures contracts originating and expiring during the period January 2011 to December 2011) The five commodities chosen are Pepper, Crude palm Oil, steel silver and Chana as they account for almost two-thirds of the value of agricultural commodity derivatives traded on NCDEX. The results of Run test indicate that both spot and futures prices are weak form efficient

  10. Studies of Four Wave Mixing in a Cold Atomic Ensemble for Efficient Generation of Photon Pairs

    NASA Astrophysics Data System (ADS)

    Ferdinand, Andrew Richard; Luo, Xijie; Becerra, Francisco Elohim

    2016-05-01

    Photon pairs generated by spontaneous four-wave mixing (FWM) in atomic ensembles provide a natural path toward quantum light-matter interfaces due to their intrinsic compatibility with atomic quantum memories. We study the generation of light from a semi-classical FWM process in an elongated ensemble of cold cesium (Cs) atoms. We investigate the generation efficiency as a function of power, detuning, and polarization of the pump fields in the process. This study will allow us to determine the pump-field parameters in our system for the efficient generation of correlated photon pairs from a spontaneous FWM process. This work is supported by AFOSR Grant FA9550-14-1-0300.

  11. ACEEE 1990 summer study on energy efficiency in buildings: Proceedings. Volume 4, Environment

    SciTech Connect

    Not Available

    1990-12-31

    This panel of the 1990 Summer Study examines the potential contribution of energy efficiency in buildings to environmental protection. The Panel also covers other aspects of the relationship between building efficiency and the environment, including indoor air quality, radon exposure, and urban heat island effects. Global environmental risks, growing interest in market-based environmental regulation, and the integration of environmental and energy planning have focused attention on energy efficiency as a low-cost pollution prevention strategy. This combination of factors is making public concern over the environment a driving force for improvements in energy efficiency. The environmental issues that are related to air pollution include the group of problems that have been in the public consciousness for two decades: acid rain, urban smog, ozone depletion, and general outdoor air pollution. Indoor air quality is also an air pollution problem. Whereas indoor air pollution causes direct health impacts on occupants of the space in question, outdoor air pollution affects others, often at remote locations, in ways that are more difficult to quantify. There is an immediacy to the indoor pollution issue that has important policy implications. The papers in the indoor air quality and radon sessions focus on several of the important issues in this area. For these conference proceedings, individual papers are processed separately for the Energy Data Base.

  12. Efficiency of particle acceleration at interplanetary shocks: Statistical study of STEREO observations

    NASA Astrophysics Data System (ADS)

    Dresing, N.; Theesen, S.; Klassen, A.; Heber, B.

    2016-04-01

    Context. Among others, shocks are known to be accelerators of energetic charged particles. However, many questions regarding the acceleration efficiency and the required conditions are not fully understood. In particular, the acceleration of electrons by shocks is often questioned. Aims: In this study we determine the efficiency of interplanetary shocks for <100 keV electrons, and for ions at ~0.1 and ~2 MeV energies, as measured by the Solar Electron and Proton Telescope (SEPT) instruments aboard the twin Solar Terrestrial Relations Observatory (STEREO) spacecraft. Methods: We employ an online STEREO in situ shock catalog that lists all shocks observed between 2007 and mid 2014 (observed by STEREO A) and until end of 2013 (observed by STEREO B). In total 475 shocks are listed. To determine the particle acceleration efficiency of these shocks, we analyze the associated intensity increases (shock spikes) during the shock crossings. For the near-relativistic electrons, we take into account the issue of possible ion contamination in the SEPT instrument. Results: The highest acceleration efficiency is found for low energy ions (0.1 MeV), which show a shock-associated increase at 27% of all shocks. The 2 MeV ions show an associated increase only during 5% of the shock crossings. In the case of the electrons, the shocks are nearly ineffective. Only five shock-associated electron increases were found, which correspond to only 1% of all shock crossings.

  13. A Study About Improvement of Efficiency of a Sewage Heat Utilization System

    NASA Astrophysics Data System (ADS)

    Kobayakawa, Tomoaki; Hihara, Eiji; Hanazaki, Hirotaka

    On the basis of the data analysis of operational performance at the DHC plant in Makuhari HB area, it is examined how the properties of the sewage used as a heat source affect the effectiveness of the system. The result of this study suggests that a sewage heat utilization system is able to perform higher efficiency when it is designed as a distributed system that has separate heat sources than a central system.

  14. A study on the coagulation of polycyclic aromatic hydrocarbon clusters to determine their collision efficiency

    SciTech Connect

    Raj, Abhijeet; Sander, Markus; Janardhanan, Vinod; Kraft, Markus

    2010-03-15

    This paper presents a theoretical study on the physical interaction between polycyclic aromatic hydrocarbons (PAHs) and their clusters of different sizes in laminar premixed flames. Two models are employed for this study: a detailed PAH growth model, referred to as the kinetic Monte Carlo - aromatic site (KMC-ARS) model [Raj et al., Combust. Flame 156 (2009) 896-913]; and a multivariate PAH population balance model, referred to as the PAH - primary particle (PAH-PP) model. Both the models are solved by kinetic Monte Carlo methods. PAH mass spectra are generated using the PAH-PP model, and compared to the experimentally observed spectra for a laminar premixed ethylene flame. The position of the maxima of PAH dimers in the spectra and their concentrations are found to depend strongly on the collision efficiency of PAH coagulation. The variation in the collision efficiency with various flame and PAH parameters is studied to determine the factors on which it may depend. A correlation for the collision efficiency is proposed by comparing the computed and the observed spectra for an ethylene flame. With this correlation, a good agreement between the computed and the observed spectra for a number of laminar premixed ethylene flames is found. (author)

  15. Preliminary thermodynamic study for an efficient turbo-blower external combustion Rankine cycle

    NASA Astrophysics Data System (ADS)

    Romero Gómez, Manuel; Romero Gómez, Javier; Ferreiro Garcia, Ramón; Baaliña Insua, Álvaro

    2014-08-01

    This research paper presents a preliminary thermodynamic study of an innovative power plant operating under a Rankine cycle fed by an external combustion system with turbo-blower (TB). The power plant comprises an external combustion system for natural gas, where the combustion gases yield their thermal energy, through a heat exchanger, to a carbon dioxide Rankine cycle operating under supercritical conditions and with quasi-critical condensation. The TB exploits the energy from the pressurised exhaust gases for compressing the combustion air. The study is focused on the comparison of the combustion system's conventional technology with that of the proposed. An energy analysis is carried out and the effect of the flue gas pressure on the efficiency and on the heat transfer in the heat exchanger is studied. The coupling of the TB results in an increase in efficiency and of the convection coefficient of the flue gas with pressure, favouring a reduced volume of the heat exchanger. The proposed innovative system achieves increases in efficiency of around 12 % as well as a decrease in the heat exchanger volume of 3/5 compared with the conventional technology without TB.

  16. The effect of a cadence retraining protocol on running biomechanics and efficiency: a pilot study.

    PubMed

    Hafer, Jocelyn F; Brown, Allison M; deMille, Polly; Hillstrom, Howard J; Garber, Carol Ewing

    2015-01-01

    Many studies have documented the association between mechanical deviations from normal and the presence or risk of injury. Some runners attempt to change mechanics by increasing running cadence. Previous work documented that increasing running cadence reduces deviations in mechanics tied to injury. The long-term effect of a cadence retraining intervention on running mechanics and energy expenditure is unknown. This study aimed to determine if increasing running cadence by 10% decreases running efficiency and changes kinematics and kinetics to make them less similar to those associated with injury. Additionally, this study aimed to determine if, after 6 weeks of cadence retraining, there would be carryover in kinematic and kinetic changes from an increased cadence state to a runner's preferred running cadence without decreased running efficiency. We measured oxygen uptake, kinematic and kinetic data on six uninjured participants before and after a 6-week intervention. Increasing cadence did not result in decreased running efficiency but did result in decreases in stride length, hip adduction angle and hip abductor moment. Carryover was observed in runners' post-intervention preferred running form as decreased hip adduction angle and vertical loading rate. PMID:25369525

  17. Energy efficiency in cognitive radio network: Study of cooperative sensing using different channel sensing methods

    NASA Astrophysics Data System (ADS)

    Cui, Chenxuan

    When cognitive radio (CR) operates, it starts by sensing spectrum and looking for idle bandwidth. There are several methods for CR to make a decision on either the channel is occupied or idle, for example, energy detection scheme, cyclostationary detection scheme and matching filtering detection scheme [1]. Among them, the most common method is energy detection scheme because of its algorithm and implementation simplicities [2]. There are two major methods for sensing, the first one is to sense single channel slot with varying bandwidth, whereas the second one is to sense multiple channels and each with same bandwidth. After sensing periods, samples are compared with a preset detection threshold and a decision is made on either the primary user (PU) is transmitting or not. Sometimes the sensing and decision results can be erroneous, for example, false alarm error and misdetection error may occur. In order to better control error probabilities and improve CR network performance (i.e. energy efficiency), we introduce cooperative sensing; in which several CR within a certain range detect and make decisions on channel availability together. The decisions are transmitted to and analyzed by a data fusion center (DFC) to make a final decision on channel availability. After the final decision is been made, DFC sends back the decision to the CRs in order to tell them to stay idle or start to transmit data to secondary receiver (SR) within a preset transmission time. After the transmission, a new cycle starts again with sensing. This thesis report is organized as followed: Chapter II review some of the papers on optimizing CR energy efficiency. In Chapter III, we study how to achieve maximal energy efficiency when CR senses single channel with changing bandwidth and with constrain on misdetection threshold in order to protect PU; furthermore, a case study is given and we calculate the energy efficiency. In Chapter IV, we study how to achieve maximal energy efficiency when CR

  18. Synthesis and Evaluation of New Generation Cross-Bridged Bifunctional Chelator for (64)Cu Radiotracers.

    PubMed

    Dale, Ajit V; An, Gwang Il; Pandya, Darpan N; Ha, Yeong Su; Bhatt, Nikunj; Soni, Nisarg; Lee, Hochun; Ahn, Heesu; Sarkar, Swarbhanu; Lee, Woonghee; Huynh, Phuong Tu; Kim, Jung Young; Gwon, Mi-Ri; Kim, Sung Hong; Park, Jae Gyu; Yoon, Young-Ran; Yoo, Jeongsoo

    2015-09-01

    Bifunctional chelators have been successfully used to construct (64)Cu-labeled radiopharmaceuticals. Previously reported chelators with cross-bridged cyclam backbones have various essential features such as high stability of the copper(II) complex, high efficiency of radiolabeling at room temperature, and good biological inertness of the radiolabeled complex, along with rapid body clearance. Here, we report a new generation propylene-cross-bridged chelator with hybrid acetate/phosphonate pendant groups (PCB-TE1A1P) developed with the aim of combining these key properties in a single chelator. The PCB-TE1A1P was synthesized from cyclam with good overall yield. The Cu(II) complex of our chelator showed good robustness in kinetic stability evaluation experiments, such as acidic decomplexation and cyclic voltammetry studies. The Cu(II) complex of PCB-TE1A1P remained intact under highly acidic conditions (12 M HCl, 90 °C) for 8 d and showed quasi-reversible reduction/oxidation peaks at -0.77 V in electrochemical studies. PCB-TE1A1P was successfully radiolabeled with (64)Cu ions in an acetate buffer at 60 °C within 60 min. The electrophoresis study revealed that the (64)Cu-PCB-TE1A1P complex has net negative charge in aqueous solution. The biodistribution and in vivo stability study profiles of (64)Cu-PCB-TE1A1P indicated that the radioactive complex was stable under physiological conditions and cleared rapidly from the body. A whole body positron emission tomography (PET) imaging study further confirmed high in vivo stability and fast clearance of the complex in mouse models. In conclusion, PCB-TE1A1P has good potential as a bifunctional chelator for (64)Cu-based radiopharmaceuticals, especially those involving peptides. PMID:26286436

  19. A Successful Case Study of Small Business Energy Efficiency and Demand Response with Communicating Thermostats

    SciTech Connect

    Herter, Karen; Wayland, Seth; Rasin, Josh

    2009-08-12

    This report documents a field study of 78 small commercial customers in the Sacramento Municipal Utility District service territory who volunteered for an integrated energy-efficiency/demand-response (EE-DR) program in the summer of 2008. The original objective for the pilot was to provide a better understanding of demand response issues in the small commercial sector. Early findings justified a focus on offering small businesses (1) help with the energy efficiency of their buildings in exchange for occasional load shed, and (2) a portfolio of options to meet the needs of a diverse customer sector. To meet these expressed needs, the research pilot provided on-site energy efficiency advice and offered participants several program options, including the choice of either a dynamic rate or monthly payment for air-conditioning setpoint control. Overall results show that pilot participants had energy savings of 20%, and the potential for an additional 14% to 20% load drop during a 100 F demand response event. In addition to the efficiency-related bill savings, participants on the dynamic rate saved an estimated 5% on their energy costs compared to the standard rate. About 80% of participants said that the program met or surpassed their expectations, and three-quarters said they would probably or definitely participate again without the $120 participation incentive. These results provide evidence that energy efficiency programs, dynamic rates and load control programs can be used concurrently and effectively in the small business sector, and that communicating thermostats are a reliable tool for providing air-conditioning load shed and enhancing the ability of customers on dynamic rates to respond to intermittent price events.

  20. Radiotracer measurements as a sensitive tool for the detection of metal penetration in molecular-based organic electronics

    SciTech Connect

    Scharnberg, M.; Hu, J.; Kanzow, J.; Raetzke, K.; Adelung, R.; Faupel, F.; Pannemann, C.; Hilleringmann, U.; Meyer, S.; Pflaum, J.

    2005-01-10

    The metallization of organic thin films is a crucial point in the development of molecular electronics. However, there is no method established yet to detect trace amounts of metal atoms in those thin films. Radiotracer measurements can quantify even very small amounts of material penetrating into the bulk, in our case less than 0.01% of a monolayer. Here, the application of this technique on two different well-characterized organic thin film systems (diindenoperylene and pentacene) is demonstrated. The results show that Ag is mainly adsorbed on the surface, but indicate that already at moderate deposition temperatures Ag can penetrate into the organic thin films and agglomerate at the film/substrate interface.

  1. The role of electromagnetic separators in the production of radiotracers for bio-medical research and nuclear medical application

    NASA Astrophysics Data System (ADS)

    Beyer, Gerd J.; Ruth, Thomas J.

    2003-05-01

    With the growing complexity of positron emission tomography/single photon emission computed tomography imaging and the new developments in systemic radionuclide therapy there is a growing need for radioisotope preparations with higher radiochemical and radionuclidic purity that has not been achievable before. Especially important for the new applications is the specific activity of the radiotracer. Conventional methods in medical isotope production have reached their technical limitations. The role of isotope separators is discussed with examples of typical production and characterization experiments conducted at the ISOLDE and TRIUMF facilities. These preliminary experiments indicate that isotope separators have a definite role to play in the future for the production of radioisotopes for biomedical research and medical application.

  2. Imaging glutamate homeostasis in cocaine addiction with the mGluR5 PET radiotracer [11C]ABP688 and Magnetic Resonance Spectroscopy

    PubMed Central

    Martinez, Diana; Slifstein, Mark; Nabulsi, Nabeel; Grassetti, Alexander; Urban, Nina; Perez, Audrey; Liu, Fei; Lin, Shu-fei; Ropchan, Jim; Mao, Xiangling; Kegeles, Lawrence S.; Shungu, Dikoma C.; Carson, Richard E.; Huang, Yiyun

    2014-01-01

    Background Preclinical studies demonstrate that glutamate homeostasis in the striatum is disrupted following cocaine exposure, including a decrease in metabotropic glutamate receptor type 5 (mGluR5) expression and reduced glutamate turnover. The goal of this study was to use imaging of the human brain to investigate alterations in the glutamate signaling in cocaine addiction. Methods Positron Emission tomography (PET) imaging with the radiotracer [11C]ABP688 was used to measure mGluR5 binding and magnetic resonance spectroscopy (MRS) was used to measure glutamate-glutamine levels in the striatum of cocaine addicted participants (n=15) compared to healthy controls (n=15). Following the scans, the cocaine addicted volunteers performed cocaine self-administration sessions in order to investigate the correlation between cocaine seeking behavior and mGluR5 receptor binding. Results The results of the study showed that cocaine addiction was associated with a 20–22% reduction in [11C]ABP688 binding in the striatum. A secondary analysis of cortical and subcortical regions other than the striatum showed a similar reduction in [11C]ABP688 binding, suggesting that the decrease is widespread. No between-group differences were seen in the MRS measures of glutamate-glutamine in the left striatum. In addition, no correlation was seen between [11C]ABP688 binding in the striatum and the choice to self-administer cocaine. Conclusions Overall, these results show that long-term cocaine use is associated with a decrease in mGluR5 availability compared to matched healthy controls and suggests that this receptor may serve as a viable target for treatment development for this disorder. PMID:24035345

  3. 124I-Epidepride: A PET Radiotracer for Extended Imaging of Dopamine D2/D3 Receptors

    PubMed Central

    Pandey, Suresh; Venugopal, Archana; Kant, Ritu; Coleman, Robert; Mukherjee, Jogeshwar

    2014-01-01

    Objectives A new radiotracer, 124I-epidepride, has been developed for the imaging of dopamine D2/3 receptors (D2/3Rs). 124I-epidepride (half-life of 124I = 4.2days) allows imaging over extended periods compared to 18F-fallypride (half-life of 18F = 0.076days) and may maximize visualization of D2/3Rs in the brain and pancreas (allowing clearance from adjacent organs). D2/3Rs are also present in pancreatic islets where they co-localize with insulin to produce granules and may serve as a surrogate marker for imaging diabetes. Methods 124I-Epidepride was synthesized using N-[[(2S)-1-ethylpyrrolidin-2-yl]methyl]-5-tributyltin-2,3-dimethoxybenzamide and 124I-iodide under no carrier added condition. Rats were used for in vitro and in vivo imaging. Brain slices were incubated with 124I-epidepride (0.75μCi/cc) and nonspecific binding measured with 10 μM haloperidol. Autoradiograms were analyzed by OptiQuant. 124I-Epidepride (0.2 to 0.3 mCi, iv) was administered to rats and brain uptake at 3 hours, 24 hours, and 48 hours post injection was evaluated. Results 124I-Epidepride was synthesized with 50% radiochemical yield and high radiochemical purity (>95%). 124I-Epidepride localized in the striatum with a striatum to cerebellum ratio of 10. Binding was displaced by dopamine and haloperidol. Brain slices demonstrated localization of 124I-epidepride up until 48 hr in the striatum. However, the extent of binding was reduced significantly. Conclusions 124I-Epidepride is a new radiotracer suitable for extended imaging of dopamine D2/3 receptors and may have applications in imaging of receptors in the brain and monitoring pancreatic islet cell grafting. PMID:24602412

  4. Quantitative analysis and efficiency study of PSD methods for a LaBr3:Ce detector

    NASA Astrophysics Data System (ADS)

    Zeng, Ming; Cang, Jirong; Zeng, Zhi; Yue, Xiaoguang; Cheng, Jianping; Liu, Yinong; Ma, Hao; Li, Junli

    2016-03-01

    The LaBr3:Ce scintillator has been widely studied for nuclear spectroscopy because of its optimal energy resolution (<3%@ 662 keV) and time resolution (~300 ps). Despite these promising properties, the intrinsic radiation background of LaBr3:Ce is a critical issue, and pulse shape discrimination (PSD) has been shown to be an efficient potential method to suppress the alpha background from the 227Ac. In this paper, the charge comparison method (CCM) for alpha and gamma discrimination in LaBr3:Ce is quantitatively analysed and compared with two other typical PSD methods using digital pulse processing. The algorithm parameters and discrimination efficiency are calculated for each method. Moreover, for the CCM, the correlation between the CCM feature value distribution and the total charge (energy) is studied, and a fitting equation for the correlation is inferred and experimentally verified. Using the equations, an energy-dependent threshold can be chosen to optimize the discrimination efficiency. Additionally, the experimental results show a potential application in low-activity high-energy γ measurement by suppressing the alpha background.

  5. Low Noise Cruise Efficient Short Take-Off and Landing Transport Vehicle Study

    NASA Technical Reports Server (NTRS)

    Kim, Hyun D.; Berton, Jeffrey J.; Jones, Scott M.

    2007-01-01

    The saturation of the airspace around current airports combined with increasingly stringent community noise limits represents a serious impediment to growth in world aviation travel. Breakthrough concepts that both increase throughput and reduce noise impacts are required to enable growth in aviation markets. Concepts with a 25 year horizon must facilitate a 4x increase in air travel while simultaneously meeting community noise constraints. Attacking these horizon issues holistically is the concept study of a Cruise Efficient Short Take-Off and Landing (CESTOL) high subsonic transport under the NASA's Revolutionary Systems Concepts for Aeronautics (RSCA) project. The concept is a high-lift capable airframe with a partially embedded distributed propulsion system that takes a synergistic approach in propulsion-airframe-integration (PAI) by fully integrating the airframe and propulsion systems to achieve the benefits of both low-noise short take-off and landing (STOL) operations and efficient high speed cruise. This paper presents a summary of the recent study of a distributed propulsion/airframe configuration that provides low-noise STOL operation to enable 24-hour use of the untapped regional and city center airports to increase the capacity of the overall airspace while still maintaining efficient high subsonic cruise flight capability.

  6. Case studies of energy efficiency financing in the original five pilot states, 1993-1996

    SciTech Connect

    Farhar, B C; Collins, N E; Walsh, R W

    1997-05-01

    The purpose of this report is to document progress in state-level programs in energy efficiency financing programs that are linked with home energy rating systems. Case studies are presented of programs in five states using a federal pilot program to amortize the costs of home energy improvements. The case studies present background information, describe the states` program, list preliminary evaluation data and findings, and discuss problems and solution encountered in the programs. A comparison of experiences in pilot states will be used to provide guidelines for program implementers, federal agencies, and Congress. 5 refs.

  7. Studies on the mechanism of efficient extraction of tea components by aqueous ethanol.

    PubMed

    Hu, Ci-Jie; Gao, Ying; Liu, Yang; Zheng, Xin-Qiang; Ye, Jian-Hui; Liang, Yue-Rong; Lu, Jian-Liang

    2016-03-01

    Effect of solvent on the extraction yield and its relevant mechanism have been studied in this paper. Compared with extraction by water, catechins and caffeine could be easily extracted from green tea by aqueous ethanol, but hardly at all by absolute ethanol. Results of the vacuum-assisted extraction, solubility determination of EGCG and caffeine, as well as swelling ratio analysis of the infused leaves, indicated that an excellent leaf-matrix-swelling effect and high solubility of tea components might be the key mechanisms for high extraction efficiency by the aqueous ethanol. These mechanisms were further confirmed by the pre-swelling extraction. This is a first report on the mechanism of efficient extraction by aqueous organic solvent. Application of pre-swelling extraction is also discussed. PMID:26471560

  8. A Study for Efficient Methods of System Calibration between Optical and Range Sensors

    NASA Astrophysics Data System (ADS)

    Choi, W.; Kim, C.; Kim, Y.

    2015-06-01

    Recently, interests in 3D indoor modeling and positioning have been growing. Data fusion by using different sensors data is one of the 3D model producing methods. For a data fusion between two kinds of sensors, precise system calibration is essential. If relative geometric location of each sensor can be accurately measured with a system-calibration, it is possible to locate a pixel that corresponds to the same object in two different images, and thus, produce a more precise data-fusion. Purpose of this study is finding more efficient method of system calibration between optical and range sensor. For this purpose, experiment was designed by considering following variables, i) system calibration method, ii) testbed type, iii) and distance data(whether use it or not). So, In this study, test-bed for system calibration was designed by considering the characteristics of sensors. Also, precise simulation was done to find efficient method of system calibration, and its results were reflected in real experiment. Results of simulation show that the bundle adjustment method is more efficient than single photo resection in system calibration between range and optical sensors. And the most efficient case was when using i) the bundle adjustment with ii) the simulated data set which were obtained between 2m to 4m away from the test-bed. These results of simulation were reflected in real system calibration. Finally, real system calibration were performed and its results were compared to results of simulation. And accuracy of system calibration was evaluated by producing fusion data between range and optical sensors.

  9. Energy Efficiency Potential in Existing Commercial Buildings: Review of Selected Recent Studies

    SciTech Connect

    Belzer, David B.

    2009-04-03

    This report reviews six recent studies (from 2002 through 2006) by states and utilities to assess the energy saving potential in existing commercial buildings. The studies cover all or portions of California, Connecticut, Vermont, Colorado, Illinois, and the Pacific Northwest. The studies clearly reveal that lighting remains the single largest and most cost effective end use that can be reduced to save energy. Overall the study indicated that with existing technologies and costs, a reasonable range of economic savings potential in existing commercial buildings is between 10 and 20 percent of current energy use. While not a focus of the study, an additional conclusion is that implementation of commercial building monitoring and controls would also play an important role in the nation’s efforts to improve energy efficiency of existing buildings.

  10. Test-retest reproducibility of binding parameters in humans with 11C-LY2795050, an antagonist PET radiotracer for the kappa opioid receptor

    PubMed Central

    Naganawa, Mika; Zheng, Ming-Qiang; Henry, Shannan; Nabulsi, Nabeel; Lin, Shu-Fei; Ropchan, Jim; Labaree, David; Najafzadeh, Soheila; Kapinos, Michael; Tauscher, Johannes; Neumeister, Alexander; Carson, Richard E.; Huang, Yiyun

    2015-01-01

    11C-LY2795050 is a new antagonist PET radioligand for the kappa opioid receptor (KOR). In this study, we assessed the reproducibility of the binding parameters of 11C-LY2795050 in healthy human subjects. Methods Sixteen healthy subjects (11 men, 5 women) underwent two separate 90-min PET scans with arterial input function and plasma free fraction measurements. The two-tissue compartment model and multilinear analysis-1 were applied to calculate five outcome measures in 14 brain regions: distribution volume (VT), distribution volume normalized by plasma free fraction (VT/fP), and three binding potentials (BPND, BPP, BPF). Since KOR is distributed ubiquitously throughout the brain, there are no suitable reference regions. We used a fixed fraction of individual cerebellum VT value as the non-displaceable distribution volume VND (= VT CER/1.17). The relative and absolute test-retest variability and intra-class correlation coefficient were evaluated for the outcome measures of 11C-LY2795050. Results The test-retest variability of 11C-LY2795050 for VT was ≤ 10% in all regions, and 12% in the amygdala. For binding potentials (BPND and BPP), the test-retest variability was good in regions of moderate and high KOR density (BPND > 0.4) and poor in regions of low density. Correction by fP (VT/fP or BPF) did not improve the test-retest performance. Conclusion Our results suggest that quantification of 11C-LY2795050 imaging is reproducible and reliable in the regions with moderate and high KOR density. Therefore we conclude that this first antagonist radiotracer is highly useful for PET studies of KOR. PMID:25593119

  11. Energy Efficiency Feasibility Study and Resulting Plan for the Bay Mills Indian Community

    SciTech Connect

    Kushman, Chris

    2014-02-03

    In 2011 the Inter-Tribal Council of Michigan, Inc. was awarded an Energy Efficiency Development and Deployment in Indian Country grant from the U.S. Department of Energy’s Tribal Energy Program. This grant aimed to study select Bay Mills Indian Community community/government buildings to determine what is required to reduce each building’s energy consumption by 30%. The Bay Mills Indian Community (BMIC) buildings with the largest expected energy use were selected for this study and included the Bay Mills Ellen Marshall Health Center building, Bay Mills Indian Community Administration Building, Bay Mills Community College main campus, Bay Mills Charter School and the Waishkey Community Center buildings. These five sites are the largest energy consuming Community buildings and comprised the study area of this project titled “Energy Efficiency Feasibility Study and Resulting Plan for the Bay Mills Indian Community”. The end objective of this study, plan and the Tribe is to reduce the energy consumption at the Community’s most energy intensive buildings that will, in turn, reduce emissions at the source of energy production, reduce energy expenditures, create long lasting energy conscious practices and positively affect the quality of the natural environment. This project’s feasibility study and resulting plan is intended to act as a guide to the Community’s first step towards planned energy management within its buildings/facilities. It aims to reduce energy consumption by 30% or greater within the subject facilities with an emphasis on energy conservation and efficiency. The energy audits and related power consumption analyses conducted for this study revealed numerous significant energy conservation and efficiency opportunities for all of the subject sites/buildings. In addition, many of the energy conservation measures require no cost and serve to help balance other measures requiring capital investment. Reoccurring deficiencies relating to heating

  12. The Efficiency Analysis of Low Impact Development Applied in Taiwan: A Case Study of Porous Pavement

    NASA Astrophysics Data System (ADS)

    Huang, Y. H.; Liu, H. J.; Hsu, N. S.; Chang, F. M.

    2014-12-01

    Low Impact Development (LID) has been developed since the end of 1990s. Lots of successful experience based on this new technology have been made. Taiwan Executive Yuan is conducting a six-year (2014~2019) program "Integrated River Basin Management Plan" applying LID to build sponge cities. Construction and Planning Agency, Ministry of the Interior is editing the manual of LID technology for Taiwan. However, since the hydrological environments, physiographic conditions, climates, the strength and frequency of disasters in Taiwan are different from that in America, this study takes the first laboratory experiment and model simulation to evaluate the efficiency of application of LID in Taiwan.LID Facilities includes porous pavement, rain garden, green roof, tree box filter facilities and so on, and in this study, porous pavement is taken as an example for discussion. In the part of laboratory experiments, the sand box experiments is designed to operate with the specified rainfall return period calculated by Horton formula and rainfall characteristics of Taipei. Then the outflow hydrograph in each designed rainfall of specified return period can be evaluated. As for model simulation, this study constructs LID simulation elements by SWMM model and tests the suitability for simulation of the outflow hydrograph obtained from experiments, and definitely quantifies the efficiency of water retention and flood reduction of porous pavement. The results fits well with the experimental observation data with less than 10% error of pick flow. It suggests that, with LID simulation elements constructed in this study, the efficiency of LID in actual on-site application can be evaluated.The results shows that porous pavement is able to delay arrival time of pick about 5% ~10% and reduce the pick flow about 5%~20%, and hold the ability of near 3~5% water retention. It proves that application of LID can retain water and reduce flood in Taiwan.

  13. Degradation efficiency of agricultural biogas plants--a full-scale study.

    PubMed

    Ruile, Stephan; Schmitz, Sabine; Mönch-Tegeder, Matthias; Oechsner, Hans

    2015-02-01

    The degradation efficiency of 21 full-scale agricultural CSTR biogas plants was investigated. The residual methane potential of the digestion stages was determined in batch digestion tests (20.0 and 37.0 °C). The results of this study showed that the residual methane yield is significantly correlated to the HRT (r=-0.73). An almost complete degradation of the input substrates was achieved due to a HRT of more than 100 days (0.097±0.017 Nm(3)/kg VS). The feedstock characteristics have the largest impact to the degradation time. It was found that standard values of the methane yield are a helpful tool for evaluating the degradation efficiency. Adapting the HRT to the input materials is the key factor for an efficient degradation in biogas plants. No influence of digester series configuration to the VS degradation was found. The mean VS degradation rate in the total reactor systems was 78±7%. PMID:25453437

  14. An empirical study on energy efficiency improvement through photovoltaic systems and a LED lighting control system

    NASA Astrophysics Data System (ADS)

    Choi, Young Kwan; Lee, Jae Hyeong

    2015-09-01

    In this research, a facility was constructed and its performance was analyzed to improve the energy efficiency of a vertical-type water treatment building. After the design and construction of a fixed tilt Photovoltaic in Building (PVIB) on the rooftop using a crystalline silicon solar cell module and photovoltaic generator integrated with the building by using a Building Integrated Photovoltaic System (BIPV), a thin-film module on the rooftop and outer wall of water treatment building, and the generation efficiency was analyzed. Also, a DC distribution was established for use of a brushless DC (BLDC) pump motor, and the existing lighting-facility-based manual on-off method was turned into a system for energy conservation by controlling light emitting diode (LED) through a wireless motion sensor and dimming control. In addition, a Building Energy Management System (BEMS) for a real-time analysis of the energy efficiency for a vertical0type water treatment building was prepared and tested. The vertical-type water treatment building developed in this study is currently operating the BEMS. The vertical-type water treatment building reported in this paper is expected to reduce energy consumption by about 30% compared to existing water treatment systems.

  15. Study on Equity and Efficiency of Health Resources and Services Based on Key Indicators in China

    PubMed Central

    Zhang, Xinyu; Zhao, Lin; Cui, Zhuang; Wang, Yaogang

    2015-01-01

    Background This study aims to evaluate the dialectical relationship between equity and efficiency of health resource allocation and health service utilization in China. Methods We analyzed the inequity of health resource allocation and health service utilization based on concentration index (CI) and Gini coefficient. Data envelopment analysis (DEA) was used to evaluate the inefficiency of resource allocation and service utilization. Factor Analysis (FA) was used to determine input/output indicators. Results The CI of Health Institutions, Beds in Health Institutions, Health Professionals and Outpatient Visits were -0.116, -0.012, 0.038, and 0.111, respectively. Gini coefficient for the 31 provinces varied between 0.05 and 0.43; out of these 23 (742%) were observed to be technically efficient constituting the “best practice frontier”. The other 8 (25.8%) provinces were technically inefficient. Conclusions Health professionals and outpatient services are focused on higher income levels, while the Health Institutions and Beds in Health Institutions were concentrated on lower income levels. In China, a few provinces attained a basic balance in both equity and efficiency in terms of current health resource and service utilization, thus serving as a reference standard for other provinces. PMID:26679187

  16. Vanadium redox flow battery efficiency and durability studies of sulfonated Diels Alder poly(phenylene)s

    SciTech Connect

    Fujimoto, Cy H.; Kim, Soowhan; Stains, Ronald; Wei, Xiaoliang; Li, Liyu; Yang, Zhenguo

    2012-07-01

    Sulfonated Diels Alder poly(phenylene) (SDAPP) was examined for vanadium redox flow battery (VRFB) use. The ion exchange capacity (IEC) was varied from 1.4, 1.6 and 2.0 meq/g in order to tune the proton conductivity and vanadium permeability. Coulombic efficiencies between 92 to 99% were observed, depending on IEC (lower IEC, higher coulombic efficiencies). In all cases the SDAPP displayed comparable energy efficiencies (88 - 90%) to Nafion 117 (88%) at 50mA/cm2. Membrane durability also was dependent on IEC; SDAPP with the highest IEC lasted slightly over 50 cycles while SDAPP with the lowest IEC lasted over 400 cycles and testing was discontinued only due to time constraints. Accelerated vanadium lifetime studies were initialed with SDAPP, by soaking films in a 0.1 M V5+ and 5.0 M total SO4-2 solution. The rate of degradation was also proportional with IEC; the 2 meq/g sample dissolved within 376 hours, the 1.6 meq/g sample dissolved after 860 hours, while the 1.4 meq/g sample broke apart after 1527 hours.

  17. A study of the structural efficiency of fluted core graphite-epoxy panels

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.

    1990-01-01

    The structural efficiency of compression-loaded graphite-epoxy sandwich panels with fluted cores is studied to determine their weight saving potential. Graphite-epoxy equilateral triangular elements are used to construct the fluted cores for the sandwich panels. Two panel configurations are considered. One configuration has two layers of triangular elements in the fluted core and the second configuration has only one layer of triangular elements in the core. An optimization code is used to find the minimum weight design for each panel configuration. Laminate ply orientations are limited to approx. 45, 0, and 90 deg. A constraint on the axial stiffness is included in the design process so the panel will conform to typical constraints for aircraft wing structures. Minimum thickness requirements for each laminate and maximum allowable strains are also included. A comparison is made of the calculated structural efficiency of the fluted core panels to the structural efficiency of aluminum transport aircraft structures and simple blade-stiffened graphite-epoxy panels. Limited experimental results are also included for comparison with the analytical predictions and to identify the critical failure mechanisms of graphite-epoxy fluted-core sandwich panels.

  18. Further evaluation of the carbon11-labelled D2/3 agonist PET radiotracer PHNO: reproducibility in tracer characteristics and characterization of extrastriatal binding

    PubMed Central

    Egerton, Alice; Hirani, Ella; Ahmad, Rabia; Turton, David R; Brickute, Diana; Rosso, Lula; Howes, Oliver D; Luthra, Sajinder K; Grasby, Paul M

    2014-01-01

    [11C]-(+)-PHNO is a new dopamine D2/3 receptor agonist radiotracer which has been successfully used to measure D2/3 receptor availability in experimental animals and man. Here we report in vivo evaluation in the rat of the biodistribution, metabolism, specificity, selectivity and dopamine sensitivity of carbon-11 labeled PHNO ([11C]-3-PHNO) produced by an alternative radiochemical synthesis method. [11C]-3-PHNO showed rapid metabolism and clearance from most peripheral organs and tissues. [11C]-3-PHNO, but not its polar metabolite, readily crossed the blood-brain barrier and showed high levels of uptake in the D2/3 -rich striatum. Pre-treatment with unlabelled PHNO and the D2/3 receptor antagonist raclopride indicated that binding in the striatum was specific and selective to D2/3 receptors. PET studies in anaesthetized rats revealed significant reductions in [11C]-3-PHNO binding in the striatum following amphetamine administration, indicating sensitivity to increases in endogenous dopamine concentrations. D2/3 antagonist pre-treatment additionally indicated moderate levels of [11C]-3-PHNO specific binding in several extrastriatal brain areas – most notably the olfactory bulbs and tubercles, thalamus and hypothalamus. Of particular interest, approximately 30% of [11C]-3-PHNO signal in the cerebellum – a region often used as a ‘low-binding’ reference region for PET quantification - was attributable to specific signal. These data demonstrate that [11C]-3-PHNO shows similar tracer characteristics to [11C]-(+)-PHNO, but additionally indicate that radiolabeled PHNO may be used to estimate D2/3 receptor availability in select extrastriatal brain regions with PET. PMID:19957364

  19. Governance of preventive Health Intervention and On time Verification of its Efficiency: the GIOVE Study

    PubMed Central

    Baio, Gianluca; Montagano, Giuseppe; Cauzillo, Gabriella; Locuratolo, Francesco; Becce, Gerardo; Gitto, Lara; Marcellusi, Andrea; Zweifel, Peter; Capone, Alessandro; Favato, Giampiero

    2012-01-01

    Objectives The GIOVE Study was aimed to the achievement of allocative efficiency of the budget allocated to the prevention of human papillomavirus (HPV)-induced diseases. An ex-ante determination of the most efficient allocation of resources between screening and multicohort quadrivalent immunisation programmes was followed by the ex-post assessment of the allocative efficiency actually achieved after a 12-month period. Design A bound optimisation model was developed to determine the ex-ante allocative efficiency of resources. The alternatives compared were the screening programme alone and the quadrivalent immunisation with access to screening. A sensitivity analysis was carried out to assess the uncertainty associated with the main inputs of the model. Subsequently, a cohort of girls with a complete recorded vaccination history were enrolled in an observational retrospective study for 18 months to ensure full compliance with the recommended schedule of vaccination (0, 2, 6 months) within a 12-month time horizon. Setting Basilicata region, in the south of Italy. Participants 12 848 girls aged 12, 15, 18 or 25 years. Intervention Immunisation with quadrivalent anti-HPV vaccine. Outcome measures The vaccination coverage rate was considered to be the indicator of the best achievable benefit, given the budgetary constraints. Results Assuming a vaccine price of €100 per dose, a vaccination coverage rate of 59.6% was required for the most effective allocation of resources. The optimal rate of coverage was initially in favour of the multicohort strategy of vaccination against HPV (72.8%±2%). When the price paid for the quadrivalent vaccine dropped to €85 per dose, the most efficient coverage rate (69.5%) shifted closer to the immunisation rate actually achieved during the 12-month observation period. Conclusions The bound optimisation model demonstrated to be a useful approach to the ex-ante allocation and the ex-post assessment of the resources allocated to

  20. A critical study on efficiency of different materials for fluoride removal from aqueous media

    PubMed Central

    2013-01-01

    Fluoride is a persistent and non-biodegradable pollutant that accumulates in soil, plants, wildlife and in human beings. Therefore, knowledge of its removal, using best technique with optimum efficiency is needed. The present survey highlights on efficacy of different materials for the removal of fluoride from water. The most important results of extensive studies on various key factors (pH, agitation time, initial fluoride concentration, temperature, particle size, surface area, presence and nature of counter ions and solvent dose) fluctuate fluoride removal capacity of materials are reviewed. PMID:23497619

  1. Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 2: Ground operations problems

    NASA Technical Reports Server (NTRS)

    Waldrop, Glen S.

    1990-01-01

    Operations problems and cost drivers were identified for current propulsion systems and design and technology approaches were identified to increase the operational efficiency and to reduce operations costs for future propulsion systems. To provide readily usable data for the ALS program, the results of the OEPSS study were organized into a series of OEPSS Data Books. This volume presents a detailed description of 25 major problems encountered during launch processing of current expendable and reusable launch vehicles. A concise description of each problem and its operational impact on launch processing is presented, along with potential solutions and technology recommendation.

  2. Efficient transformation of DDTs with Persulfate Activation by Zero-valent Iron Nanoparticles: A Mechanistic Study.

    PubMed

    Zhu, Changyin; Fang, Guodong; Dionysiou, Dionysios D; Liu, Cun; Gao, Juan; Qin, Wenxiu; Zhou, Dongmei

    2016-10-01

    In this study, persulfate (PS) activation by nano-Fe(0) was used to degrade dichlorodiphenyltrichloroethane (DDT), and the mechanism of this process was elucidated with EPR, GC-MS and free-radical quenching studies. It was found that DDT was degraded efficiently in PS/nano-Fe(0), and GC-MS analysis showed that benzoic acid, benzyl alcohol, dichlorobenzophenone and 2,2-bis(p-chlorophenyl)-ethane were the dominant products of DDT degradation, while only dechlorination products (DDD and DDE) were observed in nano-Fe(0) without persulfate. EPR results showed that persulfate activation by nano-Fe(0) led to the production of more sulfate radicals and hydroxyl radicals, which accounted for DDT degradation. But the free radical quenching studies suggested that the addition of ethanol to PS/nano-Fe(0) favored the reductive dechlorination of DDT, which was ascribed that the formed ethanol radical (CH(CH3)OH) enhanced the reductive dechlorination of DDT. Furthermore, the nano-Fe(0) loading not only affected the degradation efficiency of DDT, but also influenced the intermediate product distribution of DDT degradation in the PS/nano-Fe(0) process. PMID:27236432

  3. A parametric study of thrust and efficiency of an oscillating airfoil

    NASA Astrophysics Data System (ADS)

    Mackowski, A. W.; Williamson, C. H. K.

    2012-11-01

    An oscillating airfoil serves as a classic test case for a variety of unsteady phenomena in fluid mechanics. In nature, fish, birds, and insects oscillate their fins and wings to produce thrust and maneuvering forces, often studied by approximating the appendages as airfoils. On the other hand, the unsteady fluid mechanics of an oscillating airfoil involve vortex shedding and vortex advection, which are essential to understanding unsteady thrust, and worth studying in their own right. This information is useful in areas such as flow control, fluid-structure interaction, and undersea robotics. In this work, we examine the thrust and efficiency of a heaving (or pitching) foil as a function of variables such as the reduced frequency and amplitude (noting previous related studies such as Koochesfahani 1989; Anderson et al. 1998). Further, our novel experimental ``cyber-physical'' technique [Mackowski & Williamson, 2011] allows the airfoil to propel itself under its own thrust. Our experimental apparatus constantly monitors the fluid forces acting on the foil, and commands velocity to a carriage system in accordance with these forces. With this capability, we are able to measure the terminal velocity of a self-propelled airfoil, as well as its stationary thrust and efficiency.

  4. Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 1: Generic ground operations data

    NASA Technical Reports Server (NTRS)

    Byrd, Raymond J.

    1990-01-01

    This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advance Launch System (ALS) program, the results of the Operationally Efficient Propulsion System Study (OEPSS) were organized into a series of OEPSS Data Books as follows: Volume 1, Generic Ground Operations Data; Volume 2, Ground Operations Problems; Volume 3, Operations Technology; Volume 4, OEPSS Design Concepts; and Volume 5, OEPSS Final Review Briefing, which summarizes the activities and results of the study. This volume presents ground processing data for a generic LOX/LH2 booster and core propulsion system based on current STS experience. The data presented includes: top logic diagram, process flow, activities bar-chart, loaded timelines, manpower requirements in terms of duration, headcount and skill mix per operations and maintenance instruction (OMI), and critical path tasks and durations.

  5. A Study of Global Cirrus Optical and Microphysical Properties Based on an Efficient Infrared Retrieval Method

    NASA Astrophysics Data System (ADS)

    Li, Y.; Heidinger, A. K.

    2015-12-01

    Current studies of global upper tropospheric cirrus clouds from satellite observations are focused on daytime, primarily due to dependence on solar reflectance in the retrieval technique. Here, utilizing an accurate and efficient infrared based retrieval technique, cirrus cloud optical properties, including cloud optical thickness and effective particle size, are investigated using Aqua MODIS data during both day and night conditions. It is revealed that contrast of averaged day and night properties is small, despite of an apparent distinction in occurrence frequencies. The geographical differences are more pronounced. Seasonal variations, vertical distributions, as well as interrelations with other macrophysical and microphysical properties are also studied. The findings of this study will be useful for developing future cirrus cloud parameterization schemes in climate models.

  6. Ventilatory efficiency and breathing pattern in world-class cyclists: A three-year observational study.

    PubMed

    Salazar-Martínez, Eduardo; Terrados, Nicolás; Burtscher, Martin; Santalla, Alfredo; Naranjo Orellana, José

    2016-07-15

    The purpose of this three-year observational study was to analyze the ventilatory efficiency and breathing pattern in world-class professional cyclists. Twelve athletes (22.61±3.8years; 177.38±5.5cm; 68.96±5.5kg and VO2max 75.51±3.3mLkg(-1)min(-1)) were analyzed retrospectively. For each subject, respiratory and performance variables were recorded during incremental spiroergometry: oxygen uptake (VO2), carbon dioxide output (VCO2), pulmonary ventilation (VE), tidal volume (Vt), breathing frequency (fR), driving (Vt/Ti), timing (Ti/Ttot), peak power output (PPO) and maximum oxygen uptake (VO2max). Ventilatory efficiency (VE/VCO2 slope) was calculated from the beginning of exercise testing to the second ventilatory threshold (VT2). The VE/VCO2 slope was unaffected during the study period (24.63±3.07; 23.61±2:79; 24:89±2:61) with a low effect size (ES=0.04). The PPO improved significantly in the third year (365±33.74; 386.36±32.33; 415.00±24.15) (p<0.05). The breathing pattern variables, Vt/Ti and Ti/Ttot, did not change significantly over the three year period (ES=0.00; ES=0.03 respectively). These findings suggest that changes in cycling performance in world-class professional cyclists do not modify breathing variables related to the control of ventilatory efficiency. PMID:27083403

  7. Internalizing and externalizing traits predict changes in sleep efficiency in emerging adulthood: an actigraphy study

    PubMed Central

    Yaugher, Ashley C.; Alexander, Gerianne M.

    2015-01-01

    Research on psychopathology and experimental studies of sleep restriction support a relationship between sleep disruption and both internalizing and externalizing disorders. The objective of the current study was to extend this research by examining sleep, impulsivity, antisocial personality traits, and internalizing traits in a university sample. Three hundred and eighty six individuals (161 males) between the ages of 18 and 27 years (M = 18.59, SD = 0.98) wore actigraphs for 7 days and completed established measures of disorder-linked personality traits and sleep quality (i.e., Personality Assessment Inventory (PAI), Triarchic Psychopathy Measure, Barratt Impulsiveness Scale-11, and the Pittsburgh Sleep Quality Index). As expected, sleep measures and questionnaire scores fell within the normal range of values and sex differences in sleep and personality were consistent with previous research results. Similar to findings in predominantly male forensic psychiatric settings, higher levels of impulsivity predicted poorer subjective sleep quality in both women and men. Consistent with well-established associations between depression and sleep, higher levels of depression in both sexes predicted poorer subjective sleep quality. Bidirectional analyses showed that better sleep efficiency decreases depression. Finally, moderation analyses showed that gender does have a primary role in sleep efficiency and marginal effects were found. The observed relations between sleep and personality traits in a typical university sample add to converging evidence of the relationship between sleep and psychopathology and may inform our understanding of the development of psychopathology in young adulthood. PMID:26500575

  8. Internalizing and externalizing traits predict changes in sleep efficiency in emerging adulthood: an actigraphy study.

    PubMed

    Yaugher, Ashley C; Alexander, Gerianne M

    2015-01-01

    Research on psychopathology and experimental studies of sleep restriction support a relationship between sleep disruption and both internalizing and externalizing disorders. The objective of the current study was to extend this research by examining sleep, impulsivity, antisocial personality traits, and internalizing traits in a university sample. Three hundred and eighty six individuals (161 males) between the ages of 18 and 27 years (M = 18.59, SD = 0.98) wore actigraphs for 7 days and completed established measures of disorder-linked personality traits and sleep quality (i.e., Personality Assessment Inventory (PAI), Triarchic Psychopathy Measure, Barratt Impulsiveness Scale-11, and the Pittsburgh Sleep Quality Index). As expected, sleep measures and questionnaire scores fell within the normal range of values and sex differences in sleep and personality were consistent with previous research results. Similar to findings in predominantly male forensic psychiatric settings, higher levels of impulsivity predicted poorer subjective sleep quality in both women and men. Consistent with well-established associations between depression and sleep, higher levels of depression in both sexes predicted poorer subjective sleep quality. Bidirectional analyses showed that better sleep efficiency decreases depression. Finally, moderation analyses showed that gender does have a primary role in sleep efficiency and marginal effects were found. The observed relations between sleep and personality traits in a typical university sample add to converging evidence of the relationship between sleep and psychopathology and may inform our understanding of the development of psychopathology in young adulthood. PMID:26500575

  9. Presence of a highly efficient binding to bacterial contamination can distort data from binding studies

    SciTech Connect

    Balcar, V.J. )

    1990-12-01

    {sup 3}HGABA at low concentrations (5-10 nM) was bound by what appeared to be a GABA receptor binding site in bacterial contamination originating from a batch of distilled water. Under experimental conditions similar to those usually employed in {sup 3}HGABA binding studies, the apparent binding displayed a very high specific component and a high efficiency in terms of {sup 3}HGABA bound per mg of protein. The binding was blocked by muscimol but not by isoguvacine, SR95531 and nipecotic acid. These characteristics suggest that the presence of such spurious binding in the experiments using 3H-labeled ligands in brain homogenates may not always be very obvious and, moreover, it can result in subtle, but serious, distortions of data from such studies, which may not be immediately recognized.

  10. Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 4: OEPSS design concepts

    NASA Technical Reports Server (NTRS)

    Wong, George S.; Ziese, James M.; Farhangi, Shahram

    1990-01-01

    This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) program, the results of the OEPSS study have been organized into a series of OEPSS Data Books. This volume describes three propulsion concepts that will simplify the propulsion system design and significantly reduce operational requirements. The concepts include: (1) a fully integrated, booster propulsion module concept for the ALS that avoids the complex system created by using autonomous engines with numerous artificial interfaces; (2) an LOX tank aft concept which avoids potentially dangerous geysering in long LOX propellant lines; and (3) an air augmented, rocket engine nozzle afterburning propulsion concept that will significantly reduce LOX propellant requirements, reduce vehicle size and simplify ground operations and ground support equipment and facilities.

  11. FINEMAP: efficient variable selection using summary data from genome-wide association studies

    PubMed Central

    Benner, Christian; Spencer, Chris C.A.; Havulinna, Aki S.; Salomaa, Veikko; Ripatti, Samuli; Pirinen, Matti

    2016-01-01

    Motivation: The goal of fine-mapping in genomic regions associated with complex diseases and traits is to identify causal variants that point to molecular mechanisms behind the associations. Recent fine-mapping methods using summary data from genome-wide association studies rely on exhaustive search through all possible causal configurations, which is computationally expensive. Results: We introduce FINEMAP, a software package to efficiently explore a set of the most important causal configurations of the region via a shotgun stochastic search algorithm. We show that FINEMAP produces accurate results in a fraction of processing time of existing approaches and is therefore a promising tool for analyzing growing amounts of data produced in genome-wide association studies and emerging sequencing projects. Availability and implementation: FINEMAP v1.0 is freely available for Mac OS X and Linux at http://www.christianbenner.com. Contact: christian.benner@helsinki.fi or matti.pirinen@helsinki.fi PMID:26773131

  12. Experimental study of the thermal-acoustic efficiency in a long turbulent diffusion-flame burner

    NASA Technical Reports Server (NTRS)

    Mahan, J. R.

    1983-01-01

    A two-year study of noise production in a long tubular burner is described. The research was motivated by an interest in understanding and eventually reducing core noise in gas turbine engines. The general approach is to employ an acoustic source/propagation model to interpret the sound pressure spectrum in the acoustic far field of the burner in terms of the source spectrum that must have produced it. In the model the sources are assumed to be due uniquely to the unsteady component of combustion heat release; thus only direct combustion-noise is considered. The source spectrum is then the variation with frequency of the thermal-acoustic efficiency, defined as the fraction of combustion heat release which is converted into acoustic energy at a given frequency. The thrust of the research was to study the variation of the source spectrum with the design and operating parameters of the burner.

  13. Multivariate Meta-Analysis of Heterogeneous Studies Using Only Summary Statistics: Efficiency and Robustness

    PubMed Central

    Liu, Dungang; Liu, Regina; Xie, Minge

    2014-01-01

    Meta-analysis has been widely used to synthesize evidence from multiple studies for common hypotheses or parameters of interest. However, it has not yet been fully developed for incorporating heterogeneous studies, which arise often in applications due to different study designs, populations or outcomes. For heterogeneous studies, the parameter of interest may not be estimable for certain studies, and in such a case, these studies are typically excluded from conventional meta-analysis. The exclusion of part of the studies can lead to a non-negligible loss of information. This paper introduces a metaanalysis for heterogeneous studies by combining the confidence density functions derived from the summary statistics of individual studies, hence referred to as the CD approach. It includes all the studies in the analysis and makes use of all information, direct as well as indirect. Under a general likelihood inference framework, this new approach is shown to have several desirable properties, including: i) it is asymptotically as efficient as the maximum likelihood approach using individual participant data (IPD) from all studies; ii) unlike the IPD analysis, it suffices to use summary statistics to carry out the CD approach. Individual-level data are not required; and iii) it is robust against misspecification of the working covariance structure of the parameter estimates. Besides its own theoretical significance, the last property also substantially broadens the applicability of the CD approach. All the properties of the CD approach are further confirmed by data simulated from a randomized clinical trials setting as well as by real data on aircraft landing performance. Overall, one obtains an unifying approach for combining summary statistics, subsuming many of the existing meta-analysis methods as special cases. PMID:26190875

  14. Efficiency of goal-oriented communicating agents in different graph topologies: A study with Internet crawlers

    NASA Astrophysics Data System (ADS)

    Lőrincz, András; Lázár, Katalin A.; Palotai, Zsolt

    2007-05-01

    To what extent does the communication make a goal-oriented community efficient in different topologies? In order to gain insight into this problem, we study the influence of learning method as well as that of the topology of the environment on the communication efficiency of crawlers in quest of novel information in different topics on the Internet. Individual crawlers employ selective learning, function approximation-based reinforcement learning (RL), and their combination. Selective learning, in effect, modifies the starting URL lists of the crawlers, whilst RL alters the URL orderings. Real data have been collected from the web and scale-free worlds, scale-free small world (SFSW), and random world environments (RWEs) have been created by link reorganization. In our previous experiments [ Zs. Palotai, Cs. Farkas, A. Lőrincz, Is selection optimal in scale-free small worlds?, ComPlexUs 3 (2006) 158-168], the crawlers searched for novel, genuine documents and direct communication was not possible. Herein, our finding is reproduced: selective learning performs the best and RL the worst in SFSW, whereas the combined, i.e., selective learning coupled with RL is the best-by a slight margin-in scale-free worlds. This effect is demonstrated to be more pronounced when the crawlers search for different topic-specific documents: the relative performance of the combined learning algorithm improves in all worlds, i.e., in SFSW, in SFW, and in RWE. If the tasks are more complex and the work sharing is enforced by the environment then the combined learning algorithm becomes at least equal, even superior to both the selective and the RL algorithms in most cases, irrespective of the efficiency of communication. Furthermore, communication improves the performance by a large margin and adaptive communication is advantageous in the majority of the cases.

  15. Study on light extraction efficiency of light-emitting diodes having periodically corrugated enhancement structures with different duty cycles

    NASA Astrophysics Data System (ADS)

    Ku, Hao Ming; Wang, Huei Tsz; Huang, Chen Yang; Pan, Huang Wei; Chao, Shiuh

    2016-02-01

    The duty cycle effect on the light extraction efficiency of light-emitting diodes having different periodically corrugated enhancement structures placed opposite to the emission surface was studied. The experimental results were compared with numerical simulation results. The numerical simulation was performed using a rigorous-coupled-wave-analysis method. In the case of common structures such as a patterned-sapphire structure, we found that, in general, extraction efficiency increased drastically when duty cycle was increased from zero, and then it varied relatively slowly as the duty cycle was increased further; after that, the extraction efficiency dropped drastically as the duty cycle approached 100%. However, for a structure that was composed of autocloned-photonic crystals super-imposing on the periodical corrugation, the efficiency increased monotonically with the duty cycle and reached 83.4% (corresponding to 589% enhancement efficiency) when the duty cycle approached 100%. A method for the fabrication of such high-efficiency structures was proposed.

  16. A one-step microwave-assisted synthetic method for an O/S-chemoselective route to derivatives of the first adenosine A3 PET radiotracer.

    PubMed

    Shanab, Karem; Neudorfer, Catharina; Holzer, Wolfgang; Mitterhauser, Markus; Wadsak, Wolfgang; Spreitzer, Helmut

    2014-01-01

    The synthesis of reference standards and expected in vivo metabolites of the first adenosine A3 PET radiotracer [18F]FE@SUPPY ([18F]fluoroethyl 4,6-diethyl-5-[(ethyl-sulfanyl)carbonyl]-2-phenylpyridine-3-carboxylate) was achieved by using a straightforward microwave assisted alkylation method, which allowed O/S-chemoselective alkylation of the starting material 1 to give each target compound 2-8 in a single step. PMID:24699149

  17. In Vitro Studies of Bacterial Cellulose and Magnetic Nanoparticles Smart Nanocomposites for Efficient Chronic Wounds Healing

    PubMed Central

    Bunea, Mihaela-Cristina; Stanescu, Paul; Casarica, Angela; Iovu, Horia; Zaharia, Catalin

    2015-01-01

    The quality of life of patients with chronic wounds can be extremely poor and, therefore, over the past decades, great efforts have been made to develop efficient strategies to improve the healing process and the social impact associated with these conditions. Cell based therapy, as a modern tissue engineering strategy, involves the design of 3D cell-scaffold bioconstructs obtained by preseeding drug loaded scaffolds with undifferentiated cells in order to achieve in situ functional de novo tissue. This paper reports on the development of bionanocomposites based on bacterial cellulose and magnetic nanoparticles (magnetite) for efficient chronic wounds healing. Composites were obtained directly in the cellulose bacterial culture medium by dispersing various amounts of magnetite nanoparticles during the biosynthesis process. After purification and drying, the membranes were characterized by Raman spectroscopy and X-ray diffraction to reveal the presence of magnetite within the bacterial cellulose matrix. Morphological investigation was employed through SEM and TEM analyses on bionanocomposites. The biocompatibility of these innovative materials was studied in relation to human adipose derived stem cells in terms of cellular morphology, viability, and proliferation as well as scaffolds cytotoxic potential. PMID:26106420

  18. Estimating Endogenous Dopamine Levels at D2 and D3 Receptors in Humans using the Agonist Radiotracer [11C]-(+)-PHNO

    PubMed Central

    Caravaggio, Fernando; Nakajima, Shinichiro; Borlido, Carol; Remington, Gary; Gerretsen, Philip; Wilson, Alan; Houle, Sylvain; Menon, Mahesh; Mamo, David; Graff-Guerrero, Ariel

    2014-01-01

    Using positron emission tomography (PET) and an acute dopamine depletion challenge it is possible to estimate endogenous dopamine levels occupying dopamine D2/3 receptors (D2/3R) in humans in vivo. Our group has developed [11C]-(+)-PHNO, the first agonist radiotracer with preferential in vivo affinity for D3R. Thus, the use of [11C]-(+)-PHNO offers the novel possibility of (i) estimating in vivo endogenous dopamine levels at D2/3R using an agonist radiotracer, and (ii) estimating endogenous dopamine levels at D3R in extrastriatal regions such as the substantia nigra, hypothalamus, and ventral pallidum. Ten healthy participants underwent a [11C]-(+)-PHNO PET scan under baseline conditions and another under acute endogenous dopamine depletion achieved via oral administration of alpha-methyl-para-tyrosine (64 mg/kg). [11C]-(+)-PHNO binding was sensitive to acute dopamine depletion, allowing in vivo estimates of endogenous dopamine in D2R-rich regions (caudate and putamen), mixed D2/3R-rich regions (ventral striatum and globus pallidus), and extrastriatal D3R-rich regions (hypothalamus and ventral pallidum). Dopamine depletion decreased self-reported vigor, which was correlated with the reduction in dopamine levels in the globus pallidus. [11C]-(+)-PHNO is a suitable radiotracer for use in estimating endogenous dopamine levels at D2R and D3R in neuropsychiatric populations. PMID:24874713

  19. Synthesis and Evaluation of [N-methyl-11C]N-Desmethyl-loperamide as a New and Improved PET Radiotracer for Imaging P-gp Function

    PubMed Central

    Lazarova, Neva; Zoghbi, Sami S.; Hong, Jinsoo; Seneca, Nicholas; Tuan, Ed; Gladding, Robert L.; Liow, Jeih-San; Taku, Andrew; Innis, Robert B.; Pike, Victor W.

    2009-01-01

    [11C]Loperamide has been proposed for imaging P-glycoprotein (P-gp) function with positron emission tomography (PET), but its metabolism to [N-methyl-11C]N-desmethyl-loperamide ([11C]dLop; [11C]3) precludes quantification. We considered that [11C]3 might itself be a superior radiotracer for imaging brain P-gp function and therefore aimed to prepare [11C]3 and characterize its efficacy. An amide precursor (2) was synthesized and methylated with [11C]iodomethane to give [11C]3. After administration of [11C]3 to wild type mice, brain radioactivity uptake was very low. In P-gp (mdr-1a (−/−)) knockout mice, brain uptake of radioactivity at 30 min increased about 3.5 fold by PET measures, and over seven-fold by ex vivo measures. In knockout mice, brain radioactivity was predominantly (90%) unchanged radiotracer. In monkey PET experiments, brain radioactivity uptake was also very low, but after P-gp blockade increased more than seven-fold. [11C]3 is an effective new radiotracer for imaging brain P-gp function and, in favor of future successful quantification, appears free of extensive brain-penetrant radiometabolites. PMID:18783208

  20. Design, Synthesis, and Evaluation of an (18)F-Labeled Radiotracer Based on Celecoxib-NBD for Positron Emission Tomography (PET) Imaging of Cyclooxygenase-2 (COX-2).

    PubMed

    Kaur, Jatinder; Tietz, Ole; Bhardwaj, Atul; Marshall, Alison; Way, Jenilee; Wuest, Melinda; Wuest, Frank

    2015-10-01

    A series of novel fluorine-containing cyclooxygenase-2 (COX-2) inhibitors was designed and synthesized based on the previously reported fluorescent COX-2 imaging agent celecoxib-NBD (3; NBD=7-nitrobenzofurazan). In vitro COX-1/COX-2 inhibitory data show that N-(4-fluorobenzyl)-4-(5-p-tolyl-3-trifluoromethylpyrazol-1-yl)benzenesulfonamide (5; IC50 =0.36 μM, SI>277) and N-fluoromethyl-4-(5-p-tolyl-3-trifluoromethylpyrazol-1-yl)benzenesulfonamide (6; IC50 =0.24 μM, SI>416) are potent and selective COX-2 inhibitors. Compound 5 was selected for radiolabeling with the short-lived positron emitter fluorine-18 ((18) F) and evaluated as a positron emission tomography (PET) imaging agent. Radiotracer [(18) F]5 was analyzed in vitro and in vivo using human colorectal cancer model HCA-7. Although radiotracer uptake into COX-2-expressing HCA-7 cells was high, no evidence for COX-2-specific binding was found. Radiotracer uptake into HCA-7 tumors in vivo was low and similar to that of muscle, used as reference tissue. PMID:26287271

  1. Assessment of Supply Chain Energy Efficiency Potentials: A U.S. Case Study

    SciTech Connect

    Masanet, Eric; Kramer, Klaas Jan; Homan, Gregory; Brown, Richard; Worrell, Ernst

    2009-01-01

    This paper summarizes a modeling framework that characterizes the key underlying technologies and processes that contribute to the supply chain energy use and greenhouse gas (GHG) emissions of a variety of goods and services purchased by U.S. consumers. The framework couples an input-output supply chain modeling approach with"bottom-up" fuel end use models for individual IO sectors. This fuel end use modeling detail allows energy and policy analysts to better understand the underlying technologies and processes contributing to the supply chain energy and GHG"footprints" of goods and services. To illustrate the policy-relevance of thisapproach, a case study was conducted to estimate achievable household GHG footprint reductions associated with the adoption of best practice energy-efficient supply chain technologies.

  2. Experimental Study on Efficiency Improvement of R410A Scroll Compressor for Air Conditioner

    NASA Astrophysics Data System (ADS)

    Sawai, Kiyoshi; Sakuda, Atsushi; Iida, Noboru; Hiwata, Akira; Morimoto, Takashi; Ishii, Noriaki

    In scroll compressors, an increase in oil flow rate into thecompression chamber improves sealing effectsand decreases refrigerant leakage. On the other hand, as the oil supplies the heat energy, the suction refrigerantis heated and the volumetric efficiency degreases. In the present study, we made an apparatus which suppliesthe oil into the compression chamber while measuring the mass flow rate, thus investigating the relationshipbetween the oil flow rate and the compressor performance. Experimental results indicated that the presentR410A scroll compressor provided higher performance as the oil flow rate decreased under the rated conditionof the air-conditioner. In addition, based on the experimental results, we discussed that the oil flow in thecapillary installed in the orbiting scroll was considered to be a laminar flow, and the volumetric efficiencywould degrease by the effect of a quarter of the oil heat energy.

  3. Study of anomalous charge collection efficiency in heavily irradiated silicon strip detectors

    NASA Astrophysics Data System (ADS)

    Mikuž, M.; Cindro, V.; Kramberger, G.; Mandić, I.; Zavrtanik, M.

    2011-04-01

    Anomalous charge collection efficiency observed in heavily irradiated silicon strip detectors operated at high bias voltages has been studied in terms of a simple model and experimentally using 25 ns shaping electronics and transient current technique (TCT) with edge-on laser injection. The model confirmed qualitatively the explanation by electron impact ionization in the high electric field close to the strips, but failed in the quantitative description of the collected charge. First results on a Hamamatsu strip detector irradiated to 5×1015 neq/cm2 and operated at bias voltages in excess of 1000 V exhibit charge collection similar to what obtained on Micron devices. TCT tests with local charge injection by a laser confirm the validity of a linear extrapolation of trapping to very high fluences and reveal significant charge collection from the non-depleted volume of the detector.

  4. Assessment of Supply Chain Energy Efficiency Potentials: A U.S. Case Study

    SciTech Connect

    Masanet, Eric; Kramer, Klaas Jan; Homan, Gregory; Brown, Richard; Worrell, Ernst

    2009-01-01

    This paper summarizes a modeling framework that characterizes the key underlying technologies and processes that contribute to the supply chain energy use and greenhouse gas (GHG) emissions of a variety of goods and services purchased by U.S. consumers. The framework couples an input-output supply chain modeling approach with"bottom-up" fuel end use models for individual IO sectors. This fuel end use modeling detail allows energy and policy analysts to better understand the underlying technologies and processes contributing to the supply chain energy and GHG"footprints" of goods and services. To illustrate the policy-relevance of this approach, a case study was conducted to estimate achievable household GHG footprint reductions associated with the adoption of best practice energy-efficient supply chain technologies.

  5. Study of HVDC controls through efficient dynamic digital simulation of converters

    SciTech Connect

    Padiyar, K.R. ); Sachchidanand; Srivastava, A. ); Kothari, A.G. ); Bhattacharyya, S. )

    1989-10-01

    This paper describes the converter model for 6/12 pulse operation and presents its applications for the study of the performance of converter controls. The simulation is simplified by representing the converter as a time varying equivalent circuit on the DC side which is derived on the basis of graph theory. Elimination of the need to store connection matrices and an efficient way of generating the converter equations are further innovations introduced here. The converter control based on digital techniques has been considered along with representation of voltage dependent current order limit. The results of various test simulations considering both weak and strong ac system characteristics are represented to illustrate the simulation capability.

  6. Resting metabolic rate and work efficiency of rural Beninese women: a 2-y longitudinal study.

    PubMed

    Ategbo, E A; van Raaij, J M; de Koning, F L; Hautvast, J G

    1995-03-01

    This study was performed on 34 female farmers in northern Benin during 2 consecutive years. Body composition, energy intake, energy expenditure, resting metabolic rate (RMR), and energy cost of cycling on a bicycle were measured in three periods per year. Energy intake showed seasonal fluctuations of approximately 1.7 MJ/d in 1990 and 0.6 MJ/d in 1991. Body weight fluctuated between periods, with the lowest weight in preharvest periods. Observed changes in body weight were 2.6 +/- 2.3 and 0.9 +/- 1.7 kg in 1990 and 1991, respectively. The same pattern was observed in both fat mass and fat-free mass. RMR, energy cost of cycling, and delta work efficiency did not show any seasonal changes. It is concluded that metabolic adaptation, as a response to a seasonal food shortage up to 15% of average daily intake, will not occur. PMID:7872208

  7. Design, synthesis and biological studies of efficient multivalent melanotropin ligands: tools towards melanoma diagnosis and treatment

    PubMed Central

    Brabez, Nabila; Lynch, Ronald M.; Xu, Liping; Gillies, Robert J.; Chassaing, Gerard; Lavielle, Solange; Hruby, Victor J.

    2011-01-01

    In order to achieve early detection and specific cancer treatment we propose the use of multivalent interactions in which a series of binding events leads to increased affinity and consequently to selectivity. Using melanotropin (MSH) ligands, our aim is to target melanoma cells, which overexpress melanocortin receptors. In this study, we report the design and efficient synthesis of new trivalent ligands bearing MSH ligands. Evaluation of these multimers on a cell model engineered to overexpress melanocortin 4 receptors (MC4R) showed up to a 350-fold increase in binding compared to the monomer, resulting in a trivalent construct with nanomolar affinity starting from a micromolar affinity ligand. Cyclic adenosine monophosphate (cAMP) production was also investigated leading to more insights into the effects of multivalent compounds on transduction mechanisms. PMID:21928837

  8. Ten case history studies of energy efficiency improvements in pulp and paper mills. Final report

    SciTech Connect

    Not Available

    1981-01-01

    The ten technologies chosen for case history development are: sonic sootblowing in boilers, boiler operation on oil-water emulsified fuel, energy efficient motors, computerized control of excess air for boilers, boiler control and load allocation, driving of waste-activated sludge by multiple effect evaporation, pre-drying of hog fuel, lime kiln computerization, heat wheel for process heat recovery, and organic Rankine bottoming cycle for thermomechanical pulping heat recovery. For each case study, there is given: the company name, employee contact, plant summary, a description of the energy consuming process and of the energy-saving action, an assessment of energy savings, and the decision process leading to the adoption of the measure. A data summary for discounted cash flow analysis is tabulated for each case. (LEW)

  9. Efficiency index: a new parameter to define breathing patterns during dynamic Xe-127 ventilation studies

    SciTech Connect

    Slosman, D.; Susskind, H.; Bossuyt, A.; Tang, Y.N.; Brill, A.B.

    1986-03-01

    Ventilation imaging can be improved by gating scintigraphic data with the respiratory cycle using temporal Fourier analysis (TFA) to quantify the temporal behavior of the ventilation. Sixteen consecutive images, representing equal-time increments of an average respiratory cycle, were produced by TFA in the posterior view on a pixel-by-pixel basis. An Efficiency Index (EFF), defined as the ratio of the summation of all the differences between maximum and minimum counts for each pixel to that for the entire lung during the respiratory cycle, was derived to describe the pattern of ventilation. The gated ventilation studies were carried out with Xe-127 in 12 subjects: normal lung function (4), small airway disease (2), COPD (5), and restrictive disease (1). EFF for the first three harmonics correlated linearly with FEV1 (r = 0.701, p< 0.01). This approach is suggested as a very sensitive method to quantify the extent and regional distribution of airway obstruction.

  10. Impact of environmental production conditions on productivity and efficiency: a case study of wheat farmers in Bangladesh.

    PubMed

    Rahman, Sanzidur; Hasan, M Kamrul

    2008-09-01

    Environmental conditions significantly affect production, but are often ignored in studies analysing productivity and efficiency leading to biased results. In this study, we examine the influence of selected environmental factors on productivity and efficiency in wheat farming in Bangladesh. Results reveal that environmental production conditions significantly affect the parameters of the production function and technical efficiency, as well as correlates of inefficiency. Controlling for environmental production conditions improves technical efficiency by 4 points (p<0.01) from 86% to 90%. Large farms are more efficient relative to small and medium sized farms (p<0.01 and 0.05), with no variation among regions. Policy implications include soil fertility improvement through soil conservation and crop rotation, improvement in managerial practices through extension services and adoption of modern technologies, promotion of education, strengthening the research-extension link, and development of new varieties that have higher yield potential and are also suitable for marginal areas. PMID:17764818

  11. Efficiency improvement in a vibration power generator for a linear MR damper: numerical study

    NASA Astrophysics Data System (ADS)

    Sapiński, Bogdan; Krupa, Stanisław

    2013-04-01

    This paper summarizes a numerical analysis of the electromagnetic field, voltage and circuit properties and the cogging force in a vibration power generator comprising permanent magnets and a coil with a foil winding. The device converts the energy harvested from vibrations into electrical energy which is next used to vary the damping characteristics of a linear MR damper attached to the generator. The objective of the study is to propose a sufficiently efficient generator whose finally developed (target) version could be integrated with a small-scale MR damper to build a single device. Two design options for the device are numerically studied, the previously engineered generator 1 and the newly devised generator 2. Generator 1 incorporates two magnet systems having four magnets each and a single-section coil, while generator 2 comprises three magnet systems with four magnets each and a two-section coil. Calculations were performed to determine the electromagnetic field, voltage and current properties and the cogging force in the generators. The electromagnetic field parameters include the distribution of the magnetic field, the electrical potential field and the current density in the open turn and closed turn of the generators’ coils. The voltage and current properties include electromotive force (emf) in the generators and the voltage, current, instantaneous power and energy of the magnetic field in the MR damper control coil which is represented by resistance parameter R and inductance parameter L. The cogging force expresses the magnetic interactions between the permanent magnet systems and ferromagnetic structural components of the generators. The occurrence of this force is very unfavourable and attempts should be made to reduce it through control of the parameters of the magnetic circuit components. On one hand, comparison of the numerical results for the electromagnetic field parameters and voltage and current properties revealed that for the

  12. High-efficiency particulate air filter test stand and aerosol generator for particle loading studies.

    PubMed

    Arunkumar, R; Hogancamp, Kristina U; Parsons, Michael S; Rogers, Donna M; Norton, Olin P; Nagel, Brian A; Alderman, Steven L; Waggoner, Charles A

    2007-08-01

    This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30 x 30 x 29 cm(3) nuclear grade high-efficiency particulate air (HEPA) filters under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5 to 12 standard m(3)/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150 degrees C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the particle size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA filters at and beyond rated media velocities by consistently providing, into a nominal flow of 7 standard m(3)/min, high mass concentrations (approximately 25 mg/m(3)) of dry aerosol streams having count mean diameters centered near the most penetrating particle size for HEPA filters (120-160 nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test filter. Types of filter performance related studies that can be performed using this test stand system include filter lifetime studies, filtering efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream particle size distributions. PMID

  13. High-efficiency particulate air filter test stand and aerosol generator for particle loading studies

    NASA Astrophysics Data System (ADS)

    Arunkumar, R.; Hogancamp, Kristina U.; Parsons, Michael S.; Rogers, Donna M.; Norton, Olin P.; Nagel, Brian A.; Alderman, Steven L.; Waggoner, Charles A.

    2007-08-01

    This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30×30×29cm3 nuclear grade high-efficiency particulate air (HEPA) filters under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5to12standardm3/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150°C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the particle size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA filters at and beyond rated media velocities by consistently providing, into a nominal flow of 7standardm3/min, high mass concentrations (˜25mg/m3) of dry aerosol streams having count mean diameters centered near the most penetrating particle size for HEPA filters (120-160nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test filter. Types of filter performance related studies that can be performed using this test stand system include filter lifetime studies, filtering efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream particle size distributions.

  14. A rapid and efficient preparation of [123I]radiopharmaceuticals using a small HPLC (Rocket) column.

    PubMed

    Katsifis, Andrew; Papazian, Vahan; Jackson, Timothy; Loc'h, Christian

    2006-01-01

    A simplified method for the rapid and efficient preparation of [(123)I]radiopharmaceuticals is described. Three radiopharmaceuticals, [(123)I]beta-CIT, [(123)I]MIBG and [(123)I]clioquinol, were synthesised and purified as model compounds. The radiotracers were labelled with iodine-123 using electrophilic oxidative conditions and purified by a compact semi-preparative reverse phase column (C-18, 3 microm, 7 x 53 mm, Alltima Rocket, Alltech) using aqueous-ethanol as HPLC solvents that were directly used for radiopharmaceutical formulation. The radiochemical purity of the radioiodinated tracers as assessed by analytical HPLC was higher than 99% with specific activity higher than 3 GBq/nmol. The total preparation time of a radiotracer ranged from 40 to 60 min and, starting from 3.7 GBq of iodine-123, more than 2.5 GBq of formulated radiopharmaceuticals were available for clinical investigations. PMID:16129607

  15. Aberrant Brain Network Efficiency in Parkinson’s Disease Patients with Tremor: A Multi-Modality Study

    PubMed Central

    Zhang, Delong; Wang, Jinhui; Liu, Xian; Chen, Jun; Liu, Bo

    2015-01-01

    The coordination of spontaneous brain activity is widely enhanced relative to compensation activity in Parkinson’s disease (PD) with tremor; however, the associated topological organization remains unclear. This study collected magnetic resonance imaging data from 36 participants [i.e., 16 PD patients and 20 matched normal controls (NCs)] and constructed wavelet-based functional and morphological brain networks for individual participants. Graph-based network analysis indicated that the information translation efficiency in the functional brain network was disrupted within the wavelet scale 2 (i.e., 0.063–0.125 Hz) in PD patients. Compared with the NCs, the network local efficiency was decreased and the network global efficiency was increased in PD patients. Network local efficiency could effectively discriminate PD patients from the NCs using multivariate pattern analysis, and could also describe the variability of tremor based on a multiple linear regression model (MLRM). However, these observations were not identified in the network global efficiency. Notably, the global and local efficiency were both significantly increased in the morphological brain network of PD patients. We further found that the global and local network efficiency both worked well on PD classifications (i.e., using MVPA) and clinical performance descriptions (i.e., using MLRM). More importantly, functional and morphological brain networks were highly associated in terms of network local efficiency in PD patients. This study sheds lights on network disorganization in PD with tremor and helps for understanding the neural basis underlying this type of PD. PMID:26379547

  16. Statistical efficiency and optimal design for stepped cluster studies under linear mixed effects models.

    PubMed

    Girling, Alan J; Hemming, Karla

    2016-06-15

    In stepped cluster designs the intervention is introduced into some (or all) clusters at different times and persists until the end of the study. Instances include traditional parallel cluster designs and the more recent stepped-wedge designs. We consider the precision offered by such designs under mixed-effects models with fixed time and random subject and cluster effects (including interactions with time), and explore the optimal choice of uptake times. The results apply both to cross-sectional studies where new subjects are observed at each time-point, and longitudinal studies with repeat observations on the same subjects. The efficiency of the design is expressed in terms of a 'cluster-mean correlation' which carries information about the dependency-structure of the data, and two design coefficients which reflect the pattern of uptake-times. In cross-sectional studies the cluster-mean correlation combines information about the cluster-size and the intra-cluster correlation coefficient. A formula is given for the 'design effect' in both cross-sectional and longitudinal studies. An algorithm for optimising the choice of uptake times is described and specific results obtained for the best balanced stepped designs. In large studies we show that the best design is a hybrid mixture of parallel and stepped-wedge components, with the proportion of stepped wedge clusters equal to the cluster-mean correlation. The impact of prior uncertainty in the cluster-mean correlation is considered by simulation. Some specific hybrid designs are proposed for consideration when the cluster-mean correlation cannot be reliably estimated, using a minimax principle to ensure acceptable performance across the whole range of unknown values. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. PMID:26748662

  17. Comparative mesocosm study of biostimulation efficiency in two different oil-amended sub-antarctic soils.

    PubMed

    Delille, Daniel; Coulon, Frédéric

    2008-08-01

    Biological treatment has become increasingly popular as a remediation method for soils and groundwater contaminated with petroleum hydrocarbon, chlorinated solvents, and pesticides. Bioremediation has been considered for application in cold regions such as Arctic and sub-Arctic climates and Antarctica. Studies to date suggest that indigenous microbes suitable for bioremediation exist in soils in these regions. This paper reports on two case studies at the sub-Antarctic Kerguelen Island in which indigenous bacteria were found that were capable of mineralizing petroleum hydrocarbons in soil contaminated with crude oil and diesel fuel. All results demonstrate a serious influence of the soil properties on the biostimulation efficiency. Both temperature elevation and fertilizer addition have a more significant impact on the microbial assemblages in the mineral soil than in the organic one. Analysis of the hydrocarbons remaining at the end of the experiments confirmed the bacterial observations. Optimum temperature seems to be around 10 degrees C in organic soil, whereas it was higher in mineral soil. The benefit of adding nutrients was much stronger in mineral than in the organic soil. Overall, this study suggests that biostimulation treatments were driven by soil properties and that ex situ bioremediation for treatment of cold contaminated soils will allow greater control over soil temperature, a limiting factor in cold climates. PMID:18074169

  18. Efficient capture of magnetic microbeads by sequentially switched electroosmotic flow—an experimental study

    NASA Astrophysics Data System (ADS)

    Das, Debarun; Al-Rjoub, Marwan F.; Heineman, William R.; Banerjee, Rupak K.

    2016-05-01

    Magnetophoretic separation is a commonly used immunoassay technique in microfluidic platforms where magnetic microbeads (mMBs) coated with specific epitopes (antibodies) entrap target pathogens by antigen-antibody kinetics. The mMB-cell complexes are then separated from the continuous flow using an external magnetic field. The goal of this study was to design and test a microfluidic device for efficient separation of fluorescence-tagged mMBs driven by electroosmotic flow (EOF) under steady (time invariant) and switched (time varying) electric field conditions. The EOF was driven at electric fields of 100–180 V cm‑1. The mMBs were captured by a neodymium (NdFeB) permanent earth magnet. The capture efficiency (η c) of these mMBs was improved by sequential switching of the applied electric field driven-EOF. The fluorescent images of the captured mMBs, obtained using an inverted epifluorescence microscope, were quantified using image processing tools. In steady EOF, induced by constant electric field, the number of captured mMBs decreased by 72.3% when the electric field was increased from 100 V cm‑1 to 180 V cm‑1. However, alternating the direction of flow through sequential switching of EOF increased the η c by bringing the escaped mMBs back to the capture zone and increasing their residence time in the area of higher magnetic fields. The average increase in η c was 54.3% for an mMB concentration of 1  ×  106 beads ml‑1 (C 1) and 41.6% for a concentration of 2  ×  106 beads ml‑1 (C 2). These improvements were particularly significant at higher electric fields where the η c with switching was, on average, ~70% more compared to flow without switching. The technique of sequential switching demonstrates an efficient method for capture of mMBs for application in magnetophoretic immunoassay.

  19. A person-centred segmentation study in elderly care: towards efficient demand-driven care.

    PubMed

    Eissens van der Laan, M R; van Offenbeek, M A G; Broekhuis, H; Slaets, J P J

    2014-07-01

    Providing patients with more person-centred care without increasing costs is a key challenge in healthcare. A relevant but often ignored hindrance to delivering person-centred care is that the current segmentation of the population and the associated organization of healthcare supply are based on diseases. A person-centred segmentation, i.e., based on persons' own experienced difficulties in fulfilling needs, is an elementary but often overlooked first step in developing efficient demand-driven care. This paper describes a person-centred segmentation study of elderly, a large and increasing target group confronted with heterogeneous and often interrelated difficulties in their functioning. In twenty-five diverse healthcare and welfare organizations as well as elderly associations in the Netherlands, data were collected on the difficulties in biopsychosocial functioning experienced by 2019 older adults. Data were collected between March 2010 and January 2011 and sampling took place based on their (temporarily) living conditions. Factor Mixture Model was conducted to categorize the respondents into segments with relatively similar experienced difficulties concerning their functioning. First, the analyses show that older adults can be empirically categorized into five meaningful segments: feeling vital; difficulties with psychosocial coping; physical and mobility complaints; difficulties experienced in multiple domains; and feeling extremely frail. The categorization seems robust as it was replicated in two population-based samples in the Netherlands. The segmentation's usefulness is discussed and illustrated through an evaluation of the alignment between a segment's unfulfilled biopsychosocial needs and current healthcare utilization. The set of person-centred segmentation variables provides healthcare providers the option to perform a more comprehensive first triage step than only a disease-based one. The outcomes of this first step could guide a focused and

  20. Efficiency of different protocols for enamel clean-up after bracket debonding: an in vitro study

    PubMed Central

    Sigilião, Lara Carvalho Freitas; Marquezan, Mariana; Elias, Carlos Nelson; Ruellas, Antônio Carlos; Sant'Anna, Eduardo Franzotti

    2015-01-01

    Objective: This study aimed to assess the efficiency of six protocols for cleaning-up tooth enamel after bracket debonding. Methods: A total of 60 premolars were divided into six groups, according to the tools used for clean-up: 12-blade bur at low speed (G12L), 12-blade bur at high speed (G12H), 30-blade bur at low speed (G30L), DU10CO ORTHO polisher (GDU), Renew System (GR) and Diagloss polisher (GD). Mean roughness (Ra) and mean roughness depth (Rz) of enamel surface were analyzed with a profilometer. Paired t-test was used to assess Ra and Rz before and after enamel clean-up. ANOVA/Tukey tests were used for intergroup comparison. The duration of removal procedures was recorded. The association between time and variation in enamel roughness (∆Ra, ∆Rz) were evaluated by Pearson's correlation test. Enamel topography was assessed by scanning electron microscopy (SEM). Results: In Groups G12L and G12H, original enamel roughness did not change significantly. In Groups G30L, GDU, GR and GD, a smoother surface (p < 0.05) was found after clean-up. In Groups G30L and GD, the protocols used were more time-consuming than those used in the other groups. Negative and moderate correlation was observed between time and (∆Ra, ∆Rz); Ra and (∆Ra, ∆Rz); Rz (r = - 0.445, r = - 0.475, p < 0.01). Conclusion: All enamel clean-up protocols were efficient because they did not result in increased surface roughness. The longer the time spent performing the protocol, the lower the surface roughness. PMID:26560825

  1. Photoionization mass spectrometric study of HOCl: Photoionization efficiency spectrum and ionization energy

    SciTech Connect

    Thorn, R.P. Jr.; Stief, L.J.

    1999-02-18

    The photoionization efficiency (PIE) spectrum of HOCl was measured over the wavelength range {lambda} = 102--115 nm, using a discharge flow-photoionization mass spectrometer (DF-PIMS) apparatus coupled to a synchrotron radiation source. The PIE spectra displayed steplike behavior near threshold. This study represents the first determination of the HOCl photoionization efficiency spectrum and the photoionization threshold. A value of 11.12{sub 3} {+-} 0.01{sub 8} eV was obtained for the adiabatic ionization energy (IE) of HOCl from analysis of photoion thresholds, corresponding to the HOCl{sup +}(X{sup 2}A{double_prime}) {l_arrow} HOCl(X{sup 1}A{double_prime}) transition. The PIMS result is identical to the only previous experimental measurement and in good agreement with a recent ab initio calculation. From the result for IE(HOCl), a value of 999.4 {+-} 3.6 kJ mol{sup {minus}1} was calculated for {Delta}{sub f}H{degree}{sub 0}(HOCl{sup +}), and from the latter, the proton affinity of ClO at T = 0 K, PA{sub 0}(ClO), was determined to be 629.6 {+-} 3.6 kJ mol{sup {minus}1}. At 298 K, the computed values for {Delta}{sub f}H{degree}{sub 298}(HOCl{sup +}) and PA{sub 298}(ClO) are 996.5 {+-} 3.6 and 635.1 {+-} 3.6 kJ mol{sup {minus}1}, respectively.

  2. An efficient hierarchical generalized linear mixed model for pathway analysis of genome-wide association studies

    PubMed Central

    Wang, Lily; Jia, Peilin; Wolfinger, Russell D.; Chen, Xi; Grayson, Britney L.; Aune, Thomas M.; Zhao, Zhongming

    2011-01-01

    Motivation: In genome-wide association studies (GWAS) of complex diseases, genetic variants having real but weak associations often fail to be detected at the stringent genome-wide significance level. Pathway analysis, which tests disease association with combined association signals from a group of variants in the same pathway, has become increasingly popular. However, because of the complexities in genetic data and the large sample sizes in typical GWAS, pathway analysis remains to be challenging. We propose a new statistical model for pathway analysis of GWAS. This model includes a fixed effects component that models mean disease association for a group of genes, and a random effects component that models how each gene's association with disease varies about the gene group mean, thus belongs to the class of mixed effects models. Results: The proposed model is computationally efficient and uses only summary statistics. In addition, it corrects for the presence of overlapping genes and linkage disequilibrium (LD). Via simulated and real GWAS data, we showed our model improved power over currently available pathway analysis methods while preserving type I error rate. Furthermore, using the WTCCC Type 1 Diabetes (T1D) dataset, we demonstrated mixed model analysis identified meaningful biological processes that agreed well with previous reports on T1D. Therefore, the proposed methodology provides an efficient statistical modeling framework for systems analysis of GWAS. Availability: The software code for mixed models analysis is freely available at http://biostat.mc.vanderbilt.edu/LilyWang. Contact: lily.wang@vanderbilt.edu; zhongming.zhao@vanderbilt.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:21266443

  3. Efficient Enzymatic Preparation of (13) N-Labelled Amino Acids: Towards Multipurpose Synthetic Systems.

    PubMed

    da Silva, Eunice S; Gómez-Vallejo, Vanessa; Baz, Zuriñe; Llop, Jordi; López-Gallego, Fernando

    2016-09-12

    Nitrogen-13 can be efficiently produced in biomedical cyclotrons in different chemical forms, and its stable isotopes are present in the majority of biologically active molecules. Hence, it may constitute a convenient alternative to Fluorine-18 and Carbon-11 for the preparation of positron-emitter-labelled radiotracers; however, its short half-life demands for the development of simple, fast, and efficient synthetic processes. Herein, we report the one-pot, enzymatic and non-carrier-added synthesis of the (13) N-labelled amino acids l-[(13) N]alanine, [(13) N]glycine, and l-[(13) N]serine by using l-alanine dehydrogenase from Bacillus subtilis, an enzyme that catalyses the reductive amination of α-keto acids by using nicotinamide adenine dinucleotide (NADH) as the redox cofactor and ammonia as the amine source. The integration of both l-alanine dehydrogenase and formate dehydrogenase from Candida boidinii in the same reaction vessel to facilitate the in situ regeneration of NADH during the radiochemical synthesis of the amino acids allowed a 50-fold decrease in the concentration of the cofactor without compromising reaction yields. After optimization of the experimental conditions, radiochemical yields were sufficient to carry out in vivo imaging studies in small rodents. PMID:27515007

  4. Designing More Efficient Preclinical Experiments: A Simulation Study in Chemotherapy-Induced Myelosupression

    PubMed Central

    Martin, Emma C.; Aarons, Leon; Yates, James W. T.

    2016-01-01

    A new more efficient preclinical study design (referred to as a compact design) is proposed that removes the need for satellite animals for the collection of toxicokinetic (TK) data by sampling from the main study animals, taking no more than one sample in 24 h to build up a full profile over the course of the study. The compact design’s performance was tested with a simulation study, using an example of chemotherapy-induced myelosupression in rats. Data sets were simulated from a model based on available data, following both the compact design and a traditional design using satellite animals, with 100 studies being simulated for each. The effect of the compact design on parameter and variance estimates for the TK and neutrophil models were investigated, as well as the potential effect of interoccasion variability (IOV). The compact design performed equally as well as the traditional design, and had little impact on parameter or variation estimates, indicating that it would be a suitable alternative to traditional satellite designs while reducing the number of animals required. When IOV was present but not accounted for during the TK analysis some parameter estimates were biased and interindividual variation and residual errors inflated; this was reduced by allowing for IOV in the analysis. Using the compact design removes the need for a satellite group, reducing the number of animals required, without affecting the ability to model the data. If large IOV is suspected, caution should be exercised to avoid parameter estimation bias, and inflation of variability and residual error. PMID:26678701

  5. Designing More Efficient Preclinical Experiments: A Simulation Study in Chemotherapy-Induced Myelosupression.

    PubMed

    Martin, Emma C; Aarons, Leon; Yates, James W T

    2016-03-01

    A new more efficient preclinical study design (referred to as a compact design) is proposed that removes the need for satellite animals for the collection of toxicokinetic (TK) data by sampling from the main study animals, taking no more than one sample in 24 h to build up a full profile over the course of the study. The compact design's performance was tested with a simulation study, using an example of chemotherapy-induced myelosupression in rats. Data sets were simulated from a model based on available data, following both the compact design and a traditional design using satellite animals, with 100 studies being simulated for each. The effect of the compact design on parameter and variance estimates for the TK and neutrophil models were investigated, as well as the potential effect of interoccasion variability (IOV). The compact design performed equally as well as the traditional design, and had little impact on parameter or variation estimates, indicating that it would be a suitable alternative to traditional satellite designs while reducing the number of animals required. When IOV was present but not accounted for during the TK analysis some parameter estimates were biased and interindividual variation and residual errors inflated; this was reduced by allowing for IOV in the analysis. Using the compact design removes the need for a satellite group, reducing the number of animals required, without affecting the ability to model the data. If large IOV is suspected, caution should be exercised to avoid parameter estimation bias, and inflation of variability and residual error. PMID:26678701

  6. Experimental study of elementary collection efficiency of aerosols by spray: Design of the experimental device

    SciTech Connect

    Ducret, D.; Vendel, J.; Garrec. S.L.

    1995-02-01

    The safety of a nuclear power plant containment building, in which pressure and temperature could increase because of a overheating reactor accident, can be achieved by spraying water drops. The spray reduces the pressure and the temperature levels by condensation of steam on cold water drops. The more stringent thermodynamic conditions are a pressure of 5.10{sup 5} Pa (due to steam emission) and a temperature of 413 K. Moreover its energy dissipation function, the spray leads to the washout of fission product particles emitted in the reactor building atmosphere. The present study includes a large program devoted to the evaluation of realistic washout rates. The aim of this work is to develop experiments in order to determine the collection efficiency of aerosols by a single drop. To do this, the experimental device has to be designed with fundamental criteria:-Thermodynamic conditions have to be representative of post-accident atmosphere. Thermodynamic equilibrium has to be attained between the water drops and the gaseous phase. Thermophoretic, diffusiophoretic and mechanical effects have to be studied independently. Operating conditions have to be homogenous and constant during each experiment. This paper presents the design of the experimental device. In practice, the consequences on the design of each of the criteria given previously and the necessity of being representative of the real conditions will be described.

  7. Development of a modified vermireactor for efficient vermicomposting: a laboratory study.

    PubMed

    Jain, K; Singh, J; Gupta, S K

    2003-12-01

    Waste has become an index of growth. Utilization of waste materials for productivity purposes is important for both economic and environmental reasons. Vermicomposting is an important aspect as it converts waste to wealth. In this context, a modified vermireactor in place of the conventional vermireactor for efficient vermicomposting has been developed. In the conventional low- and high-rate vermireactors, the space for vermicomposting is reduced due to the thick layer of vermibed at the bottom of the reactor, thus a small amount of worm casts is produced. In the modified vermireactors there was only a thick moist cloth at the bottom in place of the thick vermibed which allowed a comparatively large quantity of organic waste to be vermicomposted as compared to conventional vermireactors. Laboratory studies showed that the modified vermireactor performed better than the conventional vermireactor in average vermicast produced and mg castings l(-1) (digester volume) day(-1). The study further showed that only the volume of the vermireactor was responsible for the high yield of worm casts. PMID:14575958

  8. A comparative study of the hovering efficiency of flapping and revolving wings.

    PubMed

    Zheng, L; Hedrick, T; Mittal, R

    2013-09-01

    Direct numerical simulations are used to explore the hovering performance and efficiency for hawkmoth-inspired flapping and revolving wings at Reynolds (Re) numbers varying from 50 to 4800. This range covers the gamut from small (fruit fly size) to large (hawkmoth size) flying insects and is also relevant to the design of micro- and nano-aerial vehicles. The flapping wing configuration chosen here corresponds to a hovering hawkmoth and the model is derived from high-speed videogrammetry of this insect. The revolving wing configuration also employs the wings of the hawkmoth but these are arranged in a dual-blade configuration typical of helicopters. Flow for both of these configurations is simulated over the range of Reynolds numbers of interest and the aerodynamic performance of the two compared. The comparison of these two seemingly different configurations raises issues regarding the appropriateness of various performance metrics and even characteristic scales; these are also addressed in the current study. Finally, the difference in the performance between the two is correlated with the flow physics of the two configurations. The study indicates that viscous forces dominate the aerodynamic power expenditure of the revolving wing to a degree not observed for the flapping wing. Consequently, the lift-to-power metric of the revolving wing declines rapidly with decreasing Reynolds numbers resulting in a hovering performance that is at least a factor of 2 lower than the flapping wing at Reynolds numbers less than about 100. PMID:23680659

  9. The impact of specific exertion on the efficiency and ease of the voice: a pilot study.

    PubMed

    Bagnall, Alison D; McCulloch, Kirsty

    2005-09-01

    Even though most singers and other professional voice users are encouraged to relax to optimize the quality and performance of the voice, observations of acclaimed singers, actors, and public speakers would suggest otherwise. These successful vocal performers appear to be energized, actively working and exerting themselves. For this reason, a study was designed to explore the role of exertion in maintaining and optimizing the voice. The focus of this study was the possibility that increasing exertion could improve the voice and might result in the voice user experiencing less strain and, therefore, more comfort and ease. Ten subjects were recorded before and after completing a workshop to develop their skills with precise use of effort involving selected parameters of the larynx and vocal tract. Self-reported ratings of degree of exertion and level of comfort were collected at the time of each recording. The preworkshop and postworkshop recordings were analyzed acoustically and perceptually to compare the degree of noise in the signal that corresponds with the efficiency of the voice. The results indicated that, for all subjects, the quality of the voice improved with an increase in the use of specific exertion. Furthermore, ease and comfort also significantly increased. PMID:16102665

  10. An efficient method for studying low-frequency two-state fluctuators

    NASA Astrophysics Data System (ADS)

    Yan, Fei; Gustavsson, Simon; Jin, Xiaoyue; Kamal, Archana; Orlando, Terry; Oliver, William

    2014-03-01

    We propose a driven-evolution-based pulse sequence as an efficient tool to study low-frequency random telegraph noise. The sequence originates from the two-dimensional chemical exchange experiment in NMR, but dramatically reduces measuring time with a one-dimensional modification. The sequence is also more sensitive to weak fluctuators than the dynamical-decoupling-type sequences. By applying the sequence to a qubit, the existence of a two-state fluctuator is characterized by an oscillating signal, whose frequency and amplitude correspond to the fluctuator's strength and correlation time respectively. The method opens a way to investigate noise in the quasistatic regime, which cannot be resolved by conventional coherence-characterization methods. The pulse sequence can be used to study phenomena in Josephon-junction qubits such as quasiparticle tunneling. The Lincoln Laboratory portion of this work was sponsored by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract number FA8721-05-C-0002. Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the United States Government.

  11. Poinsettia protoplasts - a simple, robust and efficient system for transient gene expression studies

    PubMed Central

    2012-01-01

    Background Transient gene expression systems are indispensable tools in molecular biology. Yet, their routine application is limited to few plant species often requiring substantial equipment and facilities. High chloroplast and chlorophyll content may further impede downstream applications of transformed cells from green plant tissue. Results Here, we describe a fast and simple technique for the high-yield isolation and efficient transformation (>70%) of mesophyll-derived protoplasts from red leaves of the perennial plant Poinsettia (Euphorbia pulccherrima). In this method no particular growth facilities or expensive equipments are needed. Poinsettia protoplasts display an astonishing robustness and can be employed in a variety of commonly-used downstream applications, such as subcellular localisation (multi-colour fluorescence) or promoter activity studies. Due to low abundance of chloroplasts or chromoplasts, problems encountered in other mesophyll-derived protoplast systems (particularly autofluorescence) are alleviated. Furthermore, the transgene expression is detectable within 90 minutes of transformation and lasts for several days. Conclusions The simplicity of the isolation and transformation procedure renders Poinsettia protoplasts an attractive system for transient gene expression experiments, including multi-colour fluorescence, subcellular localisation and promoter activity studies. In addition, they offer hitherto unknown possibilities for anthocyan research and industrial applications. PMID:22559320

  12. An efficient and general approach for implementing thermodynamic phase equilibria information in geophysical and geodynamic studies

    NASA Astrophysics Data System (ADS)

    Afonso, Juan Carlos; Zlotnik, Sergio; Díez, Pedro

    2015-10-01

    We present a flexible, general, and efficient approach for implementing thermodynamic phase equilibria information (in the form of sets of physical parameters) into geophysical and geodynamic studies. The approach is based on Tensor Rank Decomposition methods, which transform the original multidimensional discrete information into a separated representation that contains significantly fewer terms, thus drastically reducing the amount of information to be stored in memory during a numerical simulation or geophysical inversion. Accordingly, the amount and resolution of the thermodynamic information that can be used in a simulation or inversion increases substantially. In addition, the method is independent of the actual software used to obtain the primary thermodynamic information, and therefore, it can be used in conjunction with any thermodynamic modeling program and/or database. Also, the errors associated with the decomposition procedure are readily controlled by the user, depending on her/his actual needs (e.g., preliminary runs versus full resolution runs). We illustrate the benefits, generality, and applicability of our approach with several examples of practical interest for both geodynamic modeling and geophysical inversion/modeling. Our results demonstrate that the proposed method is a competitive and attractive candidate for implementing thermodynamic constraints into a broad range of geophysical and geodynamic studies. MATLAB implementations of the method and examples are provided as supporting information and can be downloaded from the journal's website.

  13. Ionization efficiency studies with charge breeder and conventional electron cyclotron resonance ion source

    SciTech Connect

    Koivisto, H. Tarvainen, O.; Toivanen, V.; Komppula, J.; Kronholm, R.; Lamy, T.; Angot, J.; Delahaye, P.; Maunoury, L.; Patti, G.; Standylo, L.; Steczkiewicz, O.; Choinski, J.

    2014-02-15

    Radioactive Ion Beams play an increasingly important role in several European research facility programs such as SPES, SPIRAL1 Upgrade, and SPIRAL2, but even more for those such as EURISOL. Although remarkable advances of ECRIS charge breeders (CBs) have been achieved, further studies are needed to gain insight on the physics of the charge breeding process. The fundamental plasma processes of charge breeders are studied in the frame of the European collaboration project, EMILIE, for optimizing the charge breeding. Important information on the charge breeding can be obtained by conducting similar experiments using the gas mixing and 2-frequency heating techniques with a conventional JYFL 14 GHz ECRIS and the LPSC-PHOENIX charge breeder. The first experiments were carried out with noble gases and they revealed, for example, that the effects of the gas mixing and 2-frequency heating on the production of high charge states appear to be additive for the conventional ECRIS. The results also indicate that at least in the case of noble gases the differences between the conventional ECRIS and the charge breeder cause only minor impact on the production efficiency of ion beams.

  14. An investigation of Forex market efficiency based on detrended fluctuation analysis: A case study for Iran

    NASA Astrophysics Data System (ADS)

    Abounoori, Esmaiel; Shahrazi, Mahdi; Rasekhi, Saeed

    2012-06-01

    The efficient market hypothesis (EMH) states that asset prices fully reflect all available information. As a result, speculators cannot predict the future behavior of asset prices and earn excess profits at least after adjusting for risk. Although initial tests of the EMH were performed on stock market data, the EMH was soon applied to other markets including foreign exchange (FX). This study uses the detrended fluctuation analysis (DFA) technique to test 01:12:2005-18:04:2010 Iranian Rial/US Dollar exchange rate time series data to see if it can be explained by the weak form of the EMH. Moreover, to determine changes in the degree of inefficiency over time, the whole period has been divided into four subperiods. The study shows that the Iranian Forex market (the Rial/Dollar case) is weak-form inefficient over the whole period and in each of the subperiods. However, the degree of inefficiency is not constant over time. The findings suggest that profitable risk-adjusted trades could be made using past data.

  15. On extracting design principles from biology: II. Case study-the effect of knee direction on bipedal robot running efficiency.

    PubMed

    Haberland, M; Kim, S

    2015-01-01

    Comparing the leg of an ostrich to that of a human suggests an important question to legged robot designers: should a robot's leg joint bend in the direction of running ('forwards') or opposite ('backwards')? Biological studies cannot answer this question for engineers due to significant differences between the biological and engineering domains. Instead, we investigated the inherent effect of joint bending direction on bipedal robot running efficiency by comparing energetically optimal gaits of a wide variety of robot designs sampled at random from a design space. We found that the great majority of robot designs have several locally optimal gaits with the knee bending backwards that are more efficient than the most efficient gait with the knee bending forwards. The most efficient backwards gaits do not exhibit lower touchdown losses than the most efficient forward gaits; rather, the improved efficiency of backwards gaits stems from lower torque and reduced motion at the hip. The reduced hip use of backwards gaits is enabled by the ability of the backwards knee, acting alone, to (1) propel the robot upwards and forwards simultaneously and (2) lift and protract the foot simultaneously. In the absence of other information, designers interested in building efficient bipedal robots with two-segment legs driven by electric motors should design the knee to bend backwards rather than forwards. Compared to common practices for choosing robot knee direction, application of this principle would have a strong tendency to improve robot efficiency and save design resources. PMID:25643285

  16. Experimental Study Of SHEFEX II Hypersonic Aerodynamics And Canard Efficiency In H2K

    NASA Astrophysics Data System (ADS)

    Neeb, D.; Gulhan, A.

    2011-05-01

    One main objective of the DLR SHEFEX programme is to prove that sharp edged vehicles are capable of performing a re-entry into earth atmosphere by using a simple thermal protection system consisting of flat ceramic tiles. In comparison to blunt nose configurations like the Space shuttle, which are normally used for re-entry configurations, the SHEFEX TPS design is able to significantly reduce the costs and complexity of TPS structures and simultaneously increase the aerodynamic performance of the flight vehicle [1], [2]. To study its characteristics and perform several defined in-flight experiments during re-entry, the vehicle’s attitude will be controlled actively by canards [3]. In the framework of the SHEFEX II project an experimental investigation has been conducted in the hypersonic wind tunnel H2K to characterize the aerodynamic performance of the vehicle in hypersonic flow regime. The model has a modular design to enable the study of a variety of different influencing parameters. Its 4 circumferential canards have been made independently adjustable to account for the simulation of different manoeuvre conditions. To study the control behaviour of the vehicle and validate CFD data, a variation of canard deflections, angle of attack and angle of sideslip have been applied. Tests have been carried out at Mach 7 and 8.7 with a Reynolds number sensitivity study at the lower Mach number. The model was equipped with a six component internal balance to realize accurate coefficient measurements. The flow topology has been analyzed using Schlieren images. Beside general aerodynamic performance and canard efficiencies, flow phenomena like shock impingement on the canards could be determined by Schlieren images as well as by the derived coefficients.

  17. Developing Effective and Efficient care pathways in chronic Pain: DEEP study protocol

    PubMed Central

    2014-01-01

    Background Pain affecting the face or mouth and lasting longer than three months (“chronic orofacial pain”, COFP) is relatively common in the UK. This study aims to describe and model current care pathways for COFP patients, identify areas where current pathways could be modified, and model whether these changes would improve outcomes for patients and use resources more efficiently. Methods/Design The study takes a prospective operations research approach. A cohort of primary and secondary care COFP patients (n = 240) will be recruited at differing stages of their care in order to follow and analyse their journey through care. The cohort will be followed for two years with data collected at baseline 6, 12, 18, and 24 months on: 1) experiences of the care pathway and its impacts; 2) quality of life; 3) pain; 4) use of health services and costs incurred; 5) illness perceptions. Qualitative in-depth interviews will be used to collect data on patient experiences from a purposive sub-sample of the total cohort (n = 30) at baseline, 12 and 24 months. Four separate appraisal groups (public, patient, clincian, service manager/commissioning) will then be given data from the pathway analysis and asked to determine their priority areas for change. The proposals from appraisal groups will inform an economic modelling exercise. Findings from the economic modelling will be presented as incremental costs, Quality Adjusted Life Years (QALYs), and the incremental cost per QALY gained. At the end of the modelling a series of recommendations for service change will be available for implementation or further trial if necessary. Discussion The recent white paper on health and the report from the NHS Forum identified chronic conditions as priority areas and whilst technology can improve outcomes, so can simple, appropriate and well-defined clinical care pathways. Understanding the opportunity cost related to care pathways benefits the wider NHS. This research develops a

  18. Health effects of home energy efficiency interventions in England: a modelling study

    PubMed Central

    Milner, James; Chalabi, Zaid; Das, Payel; Jones, Benjamin; Shrubsole, Clive; Davies, Mike; Wilkinson, Paul

    2015-01-01

    Objective To assess potential public health impacts of changes to indoor air quality and temperature due to energy efficiency retrofits in English dwellings to meet 2030 carbon reduction targets. Design Health impact modelling study. Setting England. Participants English household population. Intervention Three retrofit scenarios were modelled: (1) fabric and ventilation retrofits installed assuming building regulations are met; (2) as with scenario (1) but with additional ventilation for homes at risk of poor ventilation; (3) as with scenario (1) but with no additional ventilation to illustrate the potential risk of weak regulations and non-compliance. Main outcome Primary outcomes were changes in quality adjusted life years (QALYs) over 50 years from cardiorespiratory diseases, lung cancer, asthma and common mental disorders due to changes in indoor air pollutants, including secondhand tobacco smoke, PM2.5 from indoor and outdoor sources, radon, mould, and indoor winter temperatures. Results The modelling study estimates showed that scenario (1) resulted in positive effects on net mortality and morbidity of 2241 (95% credible intervals (CI) 2085 to 2397) QALYs per 10 000 persons over 50 years follow-up due to improved temperatures and reduced exposure to indoor pollutants, despite an increase in exposure to outdoor-generated particulate matter with a diameter of 2.5 μm or less (PM2.5). Scenario (2) resulted in a negative impact of −728 (95% CI −864 to −592) QALYs per 10 000 persons over 50 years due to an overall increase in indoor pollutant exposures. Scenario (3) resulted in −539 (95% CI −678 to -399) QALYs per 10 000 persons over 50 years follow-up due to an increase in indoor exposures despite the targeting of pollutants. Conclusions If properly implemented alongside ventilation, energy efficiency retrofits in housing can improve health by reducing exposure to cold and air pollutants. Maximising the health benefits requires careful

  19. Technical efficiency and productivity of Chinese county hospitals: an exploratory study in Henan province, China

    PubMed Central

    Cheng, Zhaohui; Tao, Hongbing; Cai, Miao; Lin, Haifeng; Lin, Xiaojun; Shu, Qin; Zhang, Ru-ning

    2015-01-01

    Objectives Chinese county hospitals have been excessively enlarging their scale during the healthcare reform since 2009. The purpose of this paper is to examine the technical efficiency and productivity of county hospitals during the reform process, and to determine whether, and how, efficiency is affected by various factors. Setting and participants 114 sample county hospitals were selected from Henan province, China, from 2010 to 2012. Outcome measures Data envelopment analysis was employed to estimate the technical and scale efficiency of sample hospitals. The Malmquist index was used to calculate productivity changes over time. Tobit regression was used to regress against 4 environmental factors and 5 institutional factors that affected the technical efficiency. Results (1) 112 (98.2%), 112 (98.2%) and 104 (91.2%) of the 114 sample hospitals ran inefficiently in 2010, 2011 and 2012, with average technical efficiency of 0.697, 0.748 and 0.790, respectively. (2) On average, during 2010–2012, productivity of sample county hospitals increased by 7.8%, which was produced by the progress in technical efficiency changes and technological changes of 0.9% and 6.8%, respectively. (3) Tobit regression analysis indicated that government subsidy, hospital size with above 618 beds and average length of stay assumed a negative sign with technical efficiency; bed occupancy rate, ratio of beds to nurses and ratio of nurses to physicians assumed a positive sign with technical efficiency. Conclusions There was considerable space for technical efficiency improvement in Henan county hospitals. During 2010–2012, sample hospitals experienced productivity progress; however, the adverse change in pure technical efficiency should be emphasised. Moreover, according to the Tobit results, policy interventions that strictly supervise hospital bed scale, shorten the average length of stay and coordinate the proportion among physicians, nurses and beds, would benefit hospital efficiency

  20. A Comparison of Masticatory Performance and Efficiency of Complete Dentures Made with High Impact and Flexible Resins: A Pilot Study

    PubMed Central

    Bhoyar, Anjali; Mishra, Sunil Kumar; Yadav, Naveen S.; Mahajan, Harsh

    2015-01-01

    Background In patients with extensive tooth loss, restoration of masticatory function and aesthetics is main concern for a prosthodontist. Aim of Study This study aimed to evaluate and compare differences in masticatory efficiency of patients treated with complete dentures made with either high impact or flexible resins. Setting and Design The sample size consisted of 10 study subjects. Two sets of dentures first conventional followed by flexible dentures were fabricated for each subject and both the sets of dentures were accessed for masticatory performance and efficiency. Materials and Methods This study compared the masticatory performance and efficiency of dentures by means of standardized mesh sieves. Masticatory efficiency was calculated by recording the total number of chewing cycles and time required to completely swallow a standardized food item. A patient satisfaction questionnaire was given and evaluated. Statistical Analysis Used The statistical analyses were performed using Z-test of Proportion and Paired t-test. Results The masticatory performance ratio was found to be more for hard food in conventional dentures. The values of masticatory performance ratios for soft food, time and number of masticatory strokes were indicating better masticatory efficiency of conventional dentures. Conclusion Though masticatory efficiency and performance were found to be better for patient’s dentures made with Polymethyl methacrylate (PMMA), a statistically significant number of patients reported that the flexible dentures were more satisfying than the conventional dentures. PMID:26266213

  1. The study of capacitive deionization behavior of a carbon nanotube electrode from the perspective of charge efficiency.

    PubMed

    Li, Haibo; Liang, Sen; Gao, Mangmang; Li, Guolong; Li, Jin; He, Lijun

    2015-01-01

    In this work, the capacitive deionization (CDI) performance of a single-walled carbon nanotube (CNT) electrode has been studied from the point view of charge efficiency theory. It is revealed here that the charge efficiency of a CNT electrode is strongly dependent upon the cell voltage and solution concentration. Either the high cell voltage or the low ionic strength results in a high charge efficiency, implying that CDI is expected to be a promising technique for an aqueous solution with low ionic strength. Additionally, it is found that the high decay constant and high electrical double-layer capacity are beneficial to enhance electrosorption performance. PMID:25607673

  2. Study of tracking efficiency and its systematic uncertainty from J/ψ → pp̅π+π- at BESIII

    NASA Astrophysics Data System (ADS)

    Wen-Long, Yuan; Xiao-Cong, Ai; Xiao-Bin, Ji; Shen-Jian, Chen; Yao, Zhang; Ling-Hui, Wu; Liang-Liang, Wang; Ye, Yuan

    2016-02-01

    Based on J/ψ events collected with the BESIII detector, with corresponding Monte Carlo samples, the tracking efficiency and its systematic uncertainty are studied using a control sample of J/ψ → pp̅π+π-. Validation methods and different factors influencing the tracking efficiency are presented in detail. The tracking efficiency and its systematic uncertainty for protons and pions with the transverse momentum and polar angle dependence are also discussed. Supported by Joint Funds of National Natural Science Foundation of China (U1232201), National Natural Science Foundation of China (11275210, 11205182, 11205184) and National Key Basic Research Program of China (2015CB856700)

  3. Multiphoton microscopy: an efficient tool for in-situ study of cultural heritage artifacts

    NASA Astrophysics Data System (ADS)

    Latour, Gaël.; Echard, Jean-Philippe; Didier, Marie; Schanne-Klein, Marie-Claire

    2013-05-01

    We present multimodal nonlinear optical imaging of historical artifacts by combining Two-Photon Excited Fluorescence (2PEF) and Second Harmonic Generation (SHG) microscopies. Three-dimensional (3D) non-contact laser-scanning imaging with micrometer resolution is performed without any preparation of the objects under study. 2PEF signals are emitted by a wide range of fluorophores such as pigments and binder, which can be discriminated thanks to their different emission spectral bands by using suitable spectral filters in the detection channel. SHG signals are specific for dense non-centrosymmetric organizations such as the crystalline cellulose within the wood cell walls. We also show that plaster particles exhibit SHG signals. These particles are bassanite crystals with a non-centrosymmetric crystalline structure, while the other types of calcium sulphates exhibit a centrosymmetric crystalline structure with no SHG signal. In our study, we first characterize model single-layered samples: wood, gelatin-based films containing plaster or cochineal lake and sandarac film containing cochineal lake. We then study multilayered coating systems on wood and show that multimodal nonlinear microscopy successfully reveals the 3D distribution of all components within the stratified sample. We also show that the fine structure of the wood can be assessed, even through a thick multilayered varnish coating. Finally, in situ multimodal nonlinear imaging is demonstrated in a historical violin. SHG/2PEF imaging thus appears as an efficient non-destructive and contactless 3D imaging technique for in situ investigation of historical coatings and more generally for wood characterization and coating analysis at micrometer scale.

  4. Public Health Benefits of End-Use Electrical Energy Efficiency in California: An Exploratory Study

    SciTech Connect

    McKone, Thomas E.; Lobscheid, A.B.

    2006-06-01

    This study assesses for California how increasing end-use electrical energy efficiency from installing residential insulation impacts exposures and disease burden from power-plant pollutant emissions. Installation of fiberglass attic insulation in the nearly 3 million electricity-heated homes throughout California is used as a case study. The pollutants nitrous oxides (NO{sub x}), sulfur dioxide (SO{sub 2}), fine particulate matter (PM2.5), benzo(a)pyrene, benzene, and naphthalene are selected for the assessment. Exposure is characterized separately for rural and urban environments using the CalTOX model, which is a key input to the US Environmental Protection Agency (EPA) Tool for the Reduction and Assessment of Chemicals and other environmental Impacts (TRACI). The output of CalTOX provides for urban and rural populations emissions-to-intake factors, which are expressed as an individual intake fraction (iFi). The typical iFi from power plant emissions are on the order of 10{sup -13} (g intake per g emitted) in urban and rural regions. The cumulative (rural and urban) product of emissions, population, and iFi is combined with toxic effects factors to determine human damage factors (HDFs). HDF are expressed as disability adjusted life years (DALYs) per kilogram pollutant emitted. The HDF approach is applied to the insulation case study. Upgrading existing residential insulation to US Department of Energy (DOE) recommended levels eliminates over the assmned 50-year lifetime of the insulation an estimated 1000 DALYs from power-plant emissions per million tonne (Mt) of insulation installed, mostly from the elimination of PM2.5 emissions. In comparison, the estimated burden from the manufacture of this insulation in DALYs per Mt is roughly four orders of magnitude lower than that avoided.

  5. Computerized Provider Order Entry with Pager Notification Improves Efficiency in STAT Radiographic Studies and Respiratory Treatments

    PubMed Central

    Jacobs, Brian R; Crotty, Eric; Conway, Ed; Hart, Kim Ward; Dietrich, Craig; Pettinichi, Scott; Racadio, John

    2010-01-01

    Background The use of computerized provider order entry (CPOE) has been widely linked to improvements in patient safety. We hypothesized that electronic routing of CPOE-generated orders through individual pagers would improve the efficiency of STAT radiographic studies and respiratory treatments. Methods The study was conducted in two periods before and after implementing pager notification of STAT orders. In the Baseline Period, CPOE-generated STAT orders were communicated to radiology technicians or respiratory therapists through the use of printed orders, manual paging and/or telephone communication. The time to process the order and deliver a radiology result or respiratory treatment was tracked. In the Intervention Period CPOE-generated STAT orders were electronically routed to the radiology technician’s or respiratory therapist’s pager. During both time periods, clinicians completed user satisfaction surveys. Results Using pager notification, there was a significant reduction in radiology technician arrival time (16.8±2.1 vs 7.9±0.7 mins, p<0.001). Similarly there was a significant reduction in the cumulative time required to capture the radiographic image, image availability in the picture archiving and communication system (PACS) and the verbal report from the radiologist (p<0.05). The time required in obtaining a preliminary or final radiographic written report and the total cycle times were not significantly reduced. For STAT respiratory therapy orders there was a significant reduction in the mean time from ordering to administration of respiratory therapy treatments (124.7±14.1 vs 49.8±11.4 minutes, p<0.01). Radiologists, respiratory therapists and ordering clinicians reported improved satisfaction after implementation of pager notification. Conclusion Computer-generated orders for STAT radiographic studies and respiratory treatments can be carried out significantly faster through the use of direct pager notification. The implementation of this

  6. Study on an Efficient Dehumidifying Air-conditioning System utilizing Phase Change of Intermediate Pressure Refrigerant

    NASA Astrophysics Data System (ADS)

    Maeda, Kensaku; Inaba, Hideo

    The present study has proven a new dehumidifying system that aimed to reduce the sensible heat factor(SHF) of cooling process without using additional heat to relieve the internationally indicated conflict between energy saving and dehumidification necessary for keeping adequate indoor air quality (IAQ). In this system, we used intermediate pressure refrigerant in a vapor compression refrigerating cycle as heat transfer medium of a characteristic heat exchanger to precool the process air entering into an evaporator as well as to reheat the process air leaving from the evaporator. By this system, the present results achieved higher moisture removal and consequently higher efficiency of dehumidifying process. In addition to this fact, since this system has capability of integration into air-conditioning apparatus(HVAC system), it will be able to work for wide range of cooling load by variable SHF function. In the present paper, technical information, experimental results, and simulation results which assumed to apply this system into HVAC system are reported.

  7. Dynamic light scattering as an efficient tool to study glyconanoparticle-lectin interactions.

    PubMed

    Wang, Xin; Ramström, Olof; Yan, Mingdi

    2011-10-21

    Glyconanomaterials, an emerging class of bio-functional nanomaterials, have shown promise in detecting, imaging and targeting proteins, bacteria, and cells. In this article, we report that dynamic light scattering (DLS) can be used as an efficient tool to study glyconanoparticle (GNP)--lectin interactions. Silica and Au nanoparticles (NPs) conjugated with D-mannose (Man) and D-galactose (Gal) were treated with the lectins Concanavalin A (Con A) and Ricinus communis agglutinin (RCA(120)), and the hydrodynamic volumes of the resulting aggregates were measured by DLS. The results showed that the particle size grew with increasing lectin concentration. The limit of detection (LOD) was determined to be 2.9 nM for Con A with Man-conjugated and 6.6 nM for RCA(120) with Gal-conjugated silica NPs (35 nm), respectively. The binding affinity was also determined by DLS and the results showed 3-4 orders of magnitude higher affinity of GNPs than the free ligands with lectins. The assay sensitivity and affinity were particle size dependent and decreased with increasing particle diameter. Because the method relies on the particle size growth, it is therefore general and can be applied to nanomaterials of different compositions. PMID:21858301

  8. Eriobotrya japonica seed biocomposite efficiency for copper adsorption: Isotherms, kinetics, thermodynamic and desorption studies.

    PubMed

    Mushtaq, Mehwish; Bhatti, Haq Nawaz; Iqbal, Munawar; Noreen, Saima

    2016-07-01

    Adsorption techniques are widely used to remove pollutants from wastewater; however, composites are gaining more importance due to their excellent adsorption properties. Bentonite composite with Eriobotrya japonica seed was prepared and used for the adsorption of copper (Cu) metal from aqueous media. The process variables such as pH, Cu(II) ions initial concentration, adsorbent dose, contact time and temperature were optimized for maximum Cu(II) adsorption. At pH 5, adsorbent dose 0.1 g, contact time 45 min, Cu(II) ions initial concentration 75 mg/L and temperature 45 °C, maximum Cu(II) adsorption was achieved. Desorption studies revealed that biocomposite is recyclable. Langmuir, Freundlich and Harkins-Jura isotherms as well as pseudo-first and pseudo-second-order kinetics models were applied to understand the adsorption mechanism. Thermodynamic parameters (ΔG(0), ΔH(0) and ΔS(0)) suggest that the adsorption process was spontaneous and endothermic in nature. The pseudo-second-order kinetic model and Langmuir isotherm fitted well to the adsorption data. Results showed that biocomposite was more efficient for Cu(II) adsorption in comparison to individuals native Eriobotrya japonica seed biomass and Na-bentonite. PMID:27039361

  9. Study on the correlation between state of charge and coulombic efficiency for commercial lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zheng, Yuejiu; Ouyang, Minggao; Lu, Languang; Li, Jianqiu; Zhang, Zhendong; Li, Xiangjun

    2015-09-01

    Coulombic efficiency (CE) is an important parameter for battery cells. Unfortunately, precise measurement of CE is extremely difficult, so CE is seldom focused during cell performance study. Nevertheless, correlation between stage of charge (SOC) and CE has significant impact on battery pack performance, while the influences of different correlations between SOC and CE on battery packs have never been explored as far as we know. We present a novel method which implements two series-connected cells that can determine the correlation between SOC and CE. The experimental result shows that CE is almost invariant with SOC changes for the experimental commercial LiFePO4/C cells. This paper further investigates series-connected cells with three typical correlations between SOC and CE in simulations. The simulation results indicate that cells with negative correlations between CE and SOC are preferred for series-connected battery packs, as they tend to diminish SOC difference and increase the pack capacity which can be considered as a self-balancing mechanism.

  10. Foraging efficiency of a predator flock for randomly moving prey: A simulation study

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee; Kwon, Ohsung

    2016-03-01

    Flocking behavior of animals is highly advantageous for taking food resources. The degree of the advantage is related to the ability of flock members to detect their prey and the mobility of prey individuals. In this study, to explore the relation, we constructed a model to simulate a predator flock and its randomly moving prey. The predator members have the prey detection ability, which was characterized as sensing distance, R, and a sensing angle, θ. The mobility of the prey individuals was characterized as the maximum traveling distance of an iteration time step, L. The relative flock foraging efficiency, ɛ, was defined as ɛ = 1 ‑ (Td/Tup). Tup and Td represent the spent time for the flock to eat all prey individuals and to uptake the last remaining 10% prey, respectively. Simulation results showed that ɛ increased, maximized, and decreased with the increase of R, regardless of L. As the number of prey, N, increased, the tendency of the increasing and decreasing was diluted. The result was briefly discussed in relation to the flock foraging behavior and the development of the model toward applications for real ecosystems.

  11. Study of energy efficient supercritical coal-fired power plant dynamic responses and control strategies

    NASA Astrophysics Data System (ADS)

    Mohamed, Omar R. Ibrahim

    The world is facing the challenge of global warming and environment protection. On the other hand, the demand of electricity is growing fast due to economic growth and increase in population. Since the growth in demand is also a heavy factor in energy equations, then the renewable energy alone is not able to generate enough electricity to fill the gap within a short time of period. Therefore, fossil fuel such as coal fired power plants cannot be ruled out immediately due to their generation capacity and flexibility in load following. However, any new coal fired stations should be cleaner compared with traditional power plants. Supercritical power plants are one of the most suitable choices for environmental enhancement and higher efficiency. However, there has been an issue of whether or not to adopt this technology in the UK because it is not clear whether the performance for SC plants can satisfy the British Grid Code requirement. This thesis reports a study of dynamic responses of SC power plants through mathematical modelling, and simulation for Grid Code compliance. It also presents a new control strategy based on an alternative configuration of generalized predictive control for power plant control..

  12. Numerical Study of Usage Efficiency of Multistage Filters on Mineral Leaching Process

    NASA Astrophysics Data System (ADS)

    Inkarbekov, Medet; Kuljabekov, Alibek; Alibayeva, Karlygash; Kaltayev, Aidarkhan

    2013-11-01

    The numerical study of the usage efficiency of the multistage filters setting technology is carried out on the basis of mathematical simulation. And its application on in-situ mineral leaching process is considered. So long as mineral bearing sandstone in deposit mostly is separated by interbedded layers of sands and clays, it's expedient to use multistage filters setting technology at the mineral extraction. A comparison of the extraction degree at single and multistage filters is implemented. The results of calculations show that the distribution of flow (inflow) on well height is not uniform. In the calculations the well accepted as high-permeability channel, depending on the construction of the filter. Obtained results for a multistage filters setting qualitatively conform to the experimental findings. Wellbore is considered as a surface with a constant reduced pressure in the bottomhole formation zone. But such assumption does not show a qualitative picture of the fluid flow in the bottomhole zone [Brovin K.G., Grabovnikov V.A., 1997]. To construct an accurate mathematical model it's necessary to use Navier-Stokes equation for the interior of a vertical wellbore, and the filtration law for modeling the filtration in the reservoir. Strictly speaking, it would have had to sew two laws on the contact surface of a rock and filter. Such review requires enormous computing, as far as computational grid must be sufficiently thick to cover the interior of the wellbore.

  13. Study on collection efficiency of fission products by spray: Experimental device and modelling

    SciTech Connect

    Ducret, D.; Roblot, D.; Vendel, J.; Billarand, Y.

    1997-08-01

    Consequences of an hypothetical overheating reactor accident in nuclear power plants can be limited by spraying cold water drops into containment building. The spray reduces the pressure and the temperature levels by condensation of steam and leads to the washout of fission products (aerosols and gaseous iodine). The present study includes a large program devoted to the evaluation of realistic washout rates. An experimental device (named CARAIDAS) was designed and built in order to determine the collection efficiency of aerosols and iodine absorption by drops with representative conditions of post-accident atmosphere. This experimental device is presented in the paper and more particularly: (1) the experimental enclosure in which representative thermodynamic conditions can be achieved, (2) the monosized drops generator, the drops diameter measurement and the drops collector, (3) the cesium iodide aerosols generator and the aerosols measurements. Modelling of steam condensation on drops aerosols collection and iodine absorption are described. First experimental and code results on drops and aerosols behaviour are compared. 8 refs., 18 figs.

  14. Energy efficiency advocacy groups: A study of selected interactive efforts and independent initiatives

    SciTech Connect

    Schweitzer, M.; English, M.; Schexnayder, S.; Altman, J.

    1994-03-01

    Non-utility groups participate in a myriad of activities--initiated by themselves and others--aimed at influencing the policies and actions of utilities and their regulators related to Integrated Resource Planning (IRP) and Demand-Side Management (DSM). Some of these activities are not directed toward a particular regulatory body or utility but are designed to influence public knowledge and acceptance of IRP and DSM. Other activities involve interaction with a particular utility or regulatory body. The traditional forum for this interaction is an adversarial debate (i.e., litigation or regulatory intervention) over the merits of a utility`s plan or proposed action. However, an increasingly common forum is one in which non-utility groups and utilities cooperatively develop plans, policies, and/or programs. Arrangements of this type are referred to in this report as ``interactive efforts``. This report presents the findings derived from ten case studies of energy efficiency advocacy groups (EEAG) activities to influence the use of cost-effective DSM and to promote IRP; nine of these ten cases involve some form of interactive effort and all of them also include other EEAG activities. The goal of this research is not to measure the success of individual activities of the various groups, but to glean from a collective examination of their activities an understanding of the efficacy of various types of interactive efforts and other EEAG activities and of the contextual and procedural factors that influence their outcomes.

  15. On the Relationship Between Tooth Shape and Masticatory Efficiency: A Finite Element Study.

    PubMed

    Berthaume, Michael A

    2016-05-01

    Dental topography has successfully linked disparate tooth shapes to distinct dietary categories, but not to masticatory efficiency. Here, the relationship between four dental topographic metrics and brittle food item breakdown efficiency during compressive biting was investigated using a parametric finite element model of a bunodont molar. Food item breakdown efficiency was chosen to represent masticatory efficiency as it isolated tooth-food item interactions, where most other categories of masticatory efficiency include several aspects of the masticatory process. As relative food item size may affect the presence/absence of any relationship, four isometrically scaled, hemispherical, proxy food items were considered. Topographic metrics were uncorrelated to food item breakdown efficiency irrespective of relative food item size, and dental topographic metrics were largely uncorrelated to one another. The lack of a correlation between topographic metrics and food item breakdown efficiency is not unexpected as not all food items break down in the same manner (e.g., nuts are crushed, leaves are sheared), and only one food item shape was considered. In addition, food item breakdown efficiency describes tooth-food item interactions and requires location and shape specific information, which are absent from dental topographic metrics. This makes it unlikely any one efficiency metric will be correlated to all topographic metrics. These results emphasize the need to take into account how food items break down during biting, ingestion, and mastication when investigating the mechanical relationship between food item shape, size, mechanical properties, and breakdown, and tooth shape. Anat Rec, 299:679-687, 2016. © 2016 Wiley Periodicals, Inc. PMID:26910570

  16. Can Time Efficient Exercise Improve Cardiometabolic Risk Factors in Type 2 Diabetes? A Pilot Study

    PubMed Central

    Revdal, Anders; Hollekim-Strand, Siri M.; Ingul, Charlotte B.

    2016-01-01

    Exercise is considered a cornerstone in the prevention and treatment of type 2 diabetes, but few individuals with type 2 diabetes exercise according to guidelines. We investigated the effect of two time efficient high intensity exercise interventions on exercise capacity, glycemic control and other cardiometabolic risk factors in patients with type 2 diabetes. Twenty-one individuals with type 2 diabetes were randomly assigned to low volume high intensity interval exercise (HIIE; 27 minutes/bout; 10x1-minute at 90 % of HRmax; n = 10) or extremely low volume sprint interval exercise (SIE; 10 minutes/bout; 2x20 seconds at maximum achievable intensity; n = 11) 3 days/week for 12 weeks. Aerobic exercise capacity (VO2peak), glycosylated hemoglobin (HbA1c), blood pressure and body composition were measured at baseline and post test. Both HIIE and SIE improved VO2peak (3.3 mL·min-1·kg-1, 10.4 %), p < 0.01, and 1.4 mL·min-1·kg-1 (4.6 %), p = 0.03, respectively). Only HIIE reduced body fat percentage (4.5 %, p = 0.04) and two minute heart rate recovery (11.0 bpm, p = 0.02). Neither HIIE nor SIE improved HbA1c. In conclusion, this study indicates that substantially lower exercise volumes than recommended in current guidelines can improve aerobic exercise capacity in individuals with type 2 diabetes. However, 12 weeks of time efficient high intensity exercise did not improve glycemic control, and interventions of longer duration should be investigated. Key points Low volume high-intensity interval exercise can improve peak oxygen uptake in previously sedentary individuals with type 2 diabetes The weekly exercise volumes in the two intervention groups of 81 and 30 minutes respectively, is substantially lower than recommended in current exercise guidelines and could reduce the time-barrier associated with exercise among patients with type 2 diabetes. However, 12 weeks of structured, supervised low-volume exercise did not improve glycemic control, indicating a need for

  17. Can Time Efficient Exercise Improve Cardiometabolic Risk Factors in Type 2 Diabetes? A Pilot Study.

    PubMed

    Revdal, Anders; Hollekim-Strand, Siri M; Ingul, Charlotte B

    2016-06-01

    Exercise is considered a cornerstone in the prevention and treatment of type 2 diabetes, but few individuals with type 2 diabetes exercise according to guidelines. We investigated the effect of two time efficient high intensity exercise interventions on exercise capacity, glycemic control and other cardiometabolic risk factors in patients with type 2 diabetes. Twenty-one individuals with type 2 diabetes were randomly assigned to low volume high intensity interval exercise (HIIE; 27 minutes/bout; 10x1-minute at 90 % of HRmax; n = 10) or extremely low volume sprint interval exercise (SIE; 10 minutes/bout; 2x20 seconds at maximum achievable intensity; n = 11) 3 days/week for 12 weeks. Aerobic exercise capacity (VO2peak), glycosylated hemoglobin (HbA1c), blood pressure and body composition were measured at baseline and post test. Both HIIE and SIE improved VO2peak (3.3 mL·min(-1)·kg(-1), 10.4 %), p < 0.01, and 1.4 mL·min(-1)·kg(-1) (4.6 %), p = 0.03, respectively). Only HIIE reduced body fat percentage (4.5 %, p = 0.04) and two minute heart rate recovery (11.0 bpm, p = 0.02). Neither HIIE nor SIE improved HbA1c. In conclusion, this study indicates that substantially lower exercise volumes than recommended in current guidelines can improve aerobic exercise capacity in individuals with type 2 diabetes. However, 12 weeks of time efficient high intensity exercise did not improve glycemic control, and interventions of longer duration should be investigated. Key pointsLow volume high-intensity interval exercise can improve peak oxygen uptake in previously sedentary individuals with type 2 diabetesThe weekly exercise volumes in the two intervention groups of 81 and 30 minutes respectively, is substantially lower than recommended in current exercise guidelines and could reduce the time-barrier associated with exercise among patients with type 2 diabetes.However, 12 weeks of structured, supervised low-volume exercise did not improve glycemic control, indicating a need for

  18. Simple instrument for biochemical studies of the living human brain

    SciTech Connect

    Bice, A.N.; Wagner, H.N. Jr.; Lee, M.C.; Frost, J.J.

    1986-09-01

    A simple, relatively inexpensive radiation detection system was developed for measurement of positron-emitting receptor-binding drugs in the human brain. This high-efficiency coincidence counting system requires that only a few hundred microcuries of labeled drug be administered to the subject, thereby allowing for multiple studies without an excessive radiation dose. Measurement of the binding of (/sup 11/C)-carfentanil, a high-affinity synthetic opiate, to opiate receptors in the presence and in the absence of a competitive opiate antagonist exemplifies the use of this system for estimating different degrees of receptor binding of drugs in the human brain. The instrument has also been used for measurement of the transport into the brain of other positron-emitting radiotracers, such as large neutral amino acids.

  19. Ozone production efficiency of a ship-plume: ITCT 2K2 case study.

    PubMed

    Kim, Hyun S; Kim, Yong H; Han, Kyung M; Kim, Jhoon; Song, Chul H

    2016-01-01

    Ozone production efficiency (OPE) of ship plume was first evaluated in this study, based on ship-plume photochemical/dynamic model simulations and the ship-plume composition data measured during the ITCT 2K2 (Intercontinental Transport and Chemical Transformation 2002) aircraft campaign. The averaged instantaneous OPEs (OPE(i)‾) estimated via the ship-plume photochemical/dynamic modeling for the ITCT 2K2 ship-plume ranged between 4.61 and 18.92, showing that the values vary with the extent of chemical evolution (or chemical stage) of the ship plume and the stability classes of the marine boundary layer (MBL). Together with OPE(i)‾, the equivalent OPEs (OPE(e)‾) for the entire ITCT 2K2 ship-plume were also estimated. The OPE(e)‾ values varied between 9.73 (for the stable MBL) and 12.73 (for the moderately stable MBL), which agreed well with the OPE(e)‾ of 12.85 estimated based on the ITCT 2K2 ship-plume observations. It was also found that both the model-simulated and observation-based OPE(e)‾ inside the ship-plume were 0.29-0.38 times smaller than the OPE(e)‾ calculated/measured outside the ITCT 2K2 ship-plume. Such low OPEs insides the ship plume were due to the high levels of NO and non-liner ship-plume photochemistry. Possible implications of this ship-plume OPE study in the global chemistry-transport modeling are also discussed. PMID:26009472

  20. Materials design concepts for efficient blue OLEDs: A joint theoretical and experimental study

    SciTech Connect

    Polikarpov, Evgueni; Padmaperuma, Asanga B.

    2012-04-01

    Since their discovery, organic light emitting devices have evolved from a scientific curiosity into a technology with applications in flat panel displays and the potential to revolutionize the lighting market. During their relatively short history, the technology incorporated into OLEDs has rapidly advanced. Device quantum efficiencies have increased more than 20-fold since the first OLEDs, approaching the theoretical limit for internal quantum efficiencies. , , At this point, OLED research moves towards optimization of manufacturing processes, drive circuitry, light extraction, and overall cost reduction. However, finding the organic materials that provide both operational stability and high efficiency for the devices still remains one of the biggest challenges, particularly for blue emission. In this presentation, we will describe our approach to design functional OLED materials to meet the complex criteria set forth by device efficiency and stability goals.

  1. A study on operation efficiency evaluation based on firm's financial index and benchmark selection: take China Unicom as an example

    NASA Astrophysics Data System (ADS)

    Wu, Zu-guang; Tian, Zhan-jun; Liu, Hui; Huang, Rui; Zhu, Guo-hua

    2009-07-01

    Being the only listed telecom operators of A share market, China Unicom has always been attracted many institutional investors under the concept of 3G recent years,which itself is a great technical progress expectation.Do the institutional investors or the concept of technical progress have signficant effect on the improving of firm's operating efficiency?Though reviewing the documentary about operating efficiency we find that schoolars study this problem useing the regress analyzing based on traditional production function and data envelopment analysis(DEA) and financial index anayzing and marginal function and capital labor ratio coefficient etc. All the methods mainly based on macrodata. This paper we use the micro-data of company to evaluate the operating efficiency.Using factor analyzing based on financial index and comparing the factor score of three years from 2005 to 2007, we find that China Unicom's operating efficiency is under the averge level of benchmark corporates and has't improved under the concept of 3G from 2005 to 2007.In other words,institutional investor or the conception of technical progress expectation have faint effect on the changes of China Unicom's operating efficiency. Selecting benchmark corporates as post to evaluate the operating efficiency is a characteristic of this method ,which is basicallly sipmly and direct.This method is suit for the operation efficiency evaluation of agriculture listed companies because agriculture listed also face technical progress and marketing concept such as tax-free etc.

  2. Improved Most-Probable-Number Method To Detect Sulfate-Reducing Bacteria with Natural Media and a Radiotracer

    PubMed Central

    Vester, Flemming; Ingvorsen, Kjeld

    1998-01-01

    A greatly improved most-probable-number (MPN) method for selective enumeration of sulfate-reducing bacteria (SRB) is described. The method is based on the use of natural media and radiolabeled sulfate (35SO42−). The natural media used consisted of anaerobically prepared sterilized sludge or sediment slurries obtained from sampling sites. The densities of SRB in sediment samples from Kysing Fjord (Denmark) and activated sludge were determined by using a normal MPN (N-MPN) method with synthetic cultivation media and a tracer MPN (T-MPN) method with natural media. The T-MPN method with natural media always yielded significantly higher (100- to 1,000-fold-higher) MPN values than the N-MPN method with synthetic media. The recovery of SRB from environmental samples was investigated by simultaneously measuring sulfate reduction rates (by a 35S-radiotracer method) and bacterial counts by using the T-MPN and N-MPN methods, respectively. When bacterial numbers estimated by the T-MPN method with natural media were used, specific sulfate reduction rates (qSO42−) of 10−14 to 10−13 mol of SO42− cell−1 day−1 were calculated, which is within the range of qSO42− values previously reported for pure cultures of SRB (10−15 to 10−14 mol of SO42− cell−1 day−1). qSO42− values calculated from N-MPN values obtained with synthetic media were several orders of magnitude higher (2 × 10−10 to 7 × 10−10 mol of SO42− cell−1 day−1), showing that viable counts of SRB were seriously underestimated when standard enumeration media were used. Our results demonstrate that the use of natural media results in significant improvements in estimates of the true numbers of SRB in environmental samples. PMID:9572939

  3. Study of the technology of the plasma nanostructuring of silicon to form highly efficient emission structures

    SciTech Connect

    Galperin, V. A.; Kitsyuk, E. P.; Pavlov, A. A.; Shamanaev, A. A.

    2015-12-15

    New methods for silicon nanostructuring and the possibility of raising the aspect ratios of the structures being formed are considered. It is shown that the technology developed relates to self-formation methods and is an efficient tool for improving the quality of field-emission cathodes based on carbon nanotubes (CNTs) by increasing the Si–CNT contact area and raising the efficiency of the heat sink.

  4. Study of Transport Behavior and Conversion Efficiency in Pillar Structured Neutron Detectors

    SciTech Connect

    Nikolic, R

    2007-04-26

    Room temperature, high efficiency and scalable radiation detectors can be realized by manipulating materials at the micro scale. With micro-semiconductor-pillars, we will advance the thermal neutron detection efficiency of semiconductor detectors to over 70% with 50 mm in detector thickness. New material science, new transport behavior, neutron to alpha conversion dynamics and their relationship with neutron detection will be discovered with the proposed structures.

  5. A national study of the efficiency of hospitals in urban markets.

    PubMed Central

    Ozcan, Y A; Luke, R D

    1993-01-01

    Using a sample of 3,000 urban hospitals, this article examines the contributions of selected hospital characteristics to variations in hospital technical efficiencies, while it accounts for multiple products and inputs, and controls for local environmental variations. Four hospital characteristics are examined: hospital size, membership in a multihospital system, ownership, and payer mix (managed care contracts, percent Medicare, and percent Medicaid). Ownership and percent Medicare are consistently found to be related significantly to hospital efficiency. Within the ownership variable, government hospitals tend to be more efficient and for-profit hospitals less efficient than other hospitals. Higher percentages of Medicare payment are negatively related to efficiency. While not consistently significant across all five of the MSA size categories in which the analyses are conducted, possession of managed care contracts, membership in a multihospital system, and size all are consistently related positively to hospital technical efficiency. These variables are also all significant when the hospitals are examined in a combined analysis. Percent Medicaid was not significant in any of the analyses. Implications for policy and the need for methodological work are discussed. PMID:8428810

  6. Evaluating run of the river hydropower feasibility and efficiency under climate change for UK study sites

    NASA Astrophysics Data System (ADS)

    Pasten-Zapata, Ernesto; Moggridge, Helen; Jones, Julie

    2015-04-01

    As renewable energy generation has been encouraged by the UK Government, hydropower importance has also been highlighted. Moreover, the UK Environment Agency has mapped feasible run of the river (ROR) hydropower sites within England and Wales and small hydropower schemes have been provided with economic grants by the Government to support their initial operation. However, ROR hydropower schemes depend on the available river flow volumes and are therefore vulnerable to variations in river regimes. Therefore, an analysis of the impacts of climate change towards existing and feasible run of the river schemes is important and required. The main objective of this research is to evaluate the impacts of climate change on river regimes and its implications to installed and feasible ROR hydropower operations by analyzing four study sites distributed across the UK. Study sites present different characteristics accounting for diverse properties of hydropower schemes including: catchment characteristics (topography, land use, climate, etc.), turbine type, turbine efficiency and head. Both feasible and currently operating schemes will be included in the analysis. Operating sites will be analysed according to their installed turbine type, hands off flow and maximum generation. On the other hand, feasible sites will be analysed considering different possible turbine types and changes in river flow that could affect the hands off flow and maximum generation thresholds. Future climate is simulated based on the temperature and precipitation outputs from Global Climate Models. Due to their relatively coarse resolution, output from these models will be downscaled, bias corrected and coupled to previously calibrated and validated hydrological models for each of the study catchments (linked to poster in session CL5.5/CR3.7/HS4.8/SSS12.14). By coupling model simulations of future climate change and hydrological models, future river flow volumes will be estimated and used as inputs for

  7. Simulation study to determine the impact of different design features on design efficiency in discrete choice experiments

    PubMed Central

    Vanniyasingam, Thuva; Cunningham, Charles E; Foster, Gary; Thabane, Lehana

    2016-01-01

    Objectives Discrete choice experiments (DCEs) are routinely used to elicit patient preferences to improve health outcomes and healthcare services. While many fractional factorial designs can be created, some are more statistically optimal than others. The objective of this simulation study was to investigate how varying the number of (1) attributes, (2) levels within attributes, (3) alternatives and (4) choice tasks per survey will improve or compromise the statistical efficiency of an experimental design. Design and methods A total of 3204 DCE designs were created to assess how relative design efficiency (d-efficiency) is influenced by varying the number of choice tasks (2–20), alternatives (2–5), attributes (2–20) and attribute levels (2–5) of a design. Choice tasks were created by randomly allocating attribute and attribute level combinations into alternatives. Outcome Relative d-efficiency was used to measure the optimality of each DCE design. Results DCE design complexity influenced statistical efficiency. Across all designs, relative d-efficiency decreased as the number of attributes and attribute levels increased. It increased for designs with more alternatives. Lastly, relative d-efficiency converges as the number of choice tasks increases, where convergence may not be at 100% statistical optimality. Conclusions Achieving 100% d-efficiency is heavily dependent on the number of attributes, attribute levels, choice tasks and alternatives. Further exploration of overlaps and block sizes are needed. This study's results are widely applicable for researchers interested in creating optimal DCE designs to elicit individual preferences on health services, programmes, policies and products. PMID:27436671

  8. A study on characteristic of different sample pretreatment methods to evaluate the entrapment efficiency of liposomes.

    PubMed

    Ran, Congcong; Chen, Dan; Xu, Meng; Du, Chaohui; Li, Qinglian; Jiang, Ye

    2016-08-15

    To examine how methods affect the evaluation of entrapment efficiency (EE) of liposomes, four different sample pretreatment methods were adopted in the experiment. The four sample pretreatment methods were size-exclusion chromatography (SEC), solid-phase extraction (SPE), centrifugation ultrafiltration (CF-UF) and hollow fiber centrifugal ultrafiltration (HF-CF-UF). Amphotericin B (AmB), which could self-associate to form aggregates in water is adopted as the model drugs in this paper. In the present work, it was found that the characterization results of four methods were quite different. The EE of liposome by SEC was about 93%, only 5-13% using C18 or HLB columns, and approximately 100% by CF-UF. The EE of HF-CF-UF reached up to nearly 99.0%. Further, this paper revealed the reasons making the difference of EE among four methods. Conventional SEC may distort the authentic of EE of liposomes with mainly employing some small liposomes or excessive water as eluent. For SPE, cholesterol on liposome surface could interact with the stationary phase making it hard to elute with water, and increase the risk of liposome leakage. While for CF-UF, concentration polarization was a main limitation hindering unentrapped drug to pass through membrane, making unentrapped drug undetectable in liposome. HF-CF-UF could truly reflect EE of liposomes with the concentration of unentrapped AmB lower than 25.0μg/mL. However, when the concentration was higher than 25.0μg/mL, AmB aggregates could be entrapped by hollow fiber. From the above analysis, this paper came to the conclusion that each method had its own feature in characterization. This study provided a reasonable guideline for choosing methods to character the EE of liposome. PMID:27322630

  9. Comparison of intravascular (nondiffusible) and diffusible radiotracers in diagnosis of testicular-scrotal disorders

    SciTech Connect

    Skarzynski, J.J.; Rosenberg, R.J.; Sziklas, J.J.; Walzak, M.P.; Karimeddini, M.K.; Spencer, R.P.

    1985-05-01

    The radionuclide approach to testicular-scrotal lesions has been described in the literature in terms of dynamic and static images. However, there has been little consideration of which radiopharmaceutical to utilize. In essence, the desired procedure is to estimate relative blood flow to each testicular-scrotal area. An intravascular (nondiffusible) radiolabel may therefore be advantageous. We reviewed 18 consecutive radionuclide studies that were performed for suspected testicular-scrotal pathology. Three radiopharmaceuticals were utilized; 7 with Tc-99m-RBC or HSA, 7 with Tc-99m-pertechnetate, and 4 with Tc-99m-DTPA. Studies were read ''blind'' as to the agent employed and rated on a scale of 1+ (least satisfactory) to 4+. Criteria included ability to delineate the testes-scrotum, background activity, and clarity of the dynamic phase. Studies with the intravascular labels (6 with tagged RBC and 1 with labeled HSA) had a mean rating of 3.6 out of 4. Pertechnetate studies had a rating of 3.0. Those performed with DTPA received a rating of 2.0. The major problems with DTPA studies were rapid entry into soft tissue (likely extracellular fluid), which created a high background; in addition, bladder counts detracted from imaging the testicular-scrotal region. Intravascular labels appear to be a distinct improvement over Tc-99m-pertechnetate for testicular-scrotal imaging.

  10. A generally adoptable radiotracing method for tracking carbon nanotubes in animals

    NASA Astrophysics Data System (ADS)

    Deng, Xiaoyong; Yang, Shengtao; Nie, Haiyu; Wang, Haifang; Liu, Yuanfang

    2008-02-01

    Carbon nanotube (CNT) mediated drug delivery systems have currently aroused a great deal of interest. Such delivery systems for drugs, proteins and genes have been preliminarily studied using cellular and animal models. For the further study of the pharmacokinetics and related biological behaviours of CNTs in vivo, a fast and convenient tracing method is particularly demanded. In this paper, we developed a generally adoptable tracing method for the biodistribution study of functionalized CNTs in vivo. Taurine covalently functionalized multi-walled carbon nanotubes (tau-MWNTs) and Tween-80 wrapped MWNTs (Tween-MWNTs) were labelled with 125I, and then their distribution in mice was determined. It is interesting that Tween-80 can reduce the RES uptake of MWNTs remarkably. The resulting distribution of 125I-tau-MWNTs was very consistent with that using 14C-taurine-MWNTs as the CNTs tracer, which means the easy 125I labelling method is reliable and effective.

  11. Evaluation of the In Vivo and Ex Vivo Binding of Novel BC1 Cannabinoid Receptor Radiotracers

    SciTech Connect

    Miller, A.; Gatley, J.; Gifford, A.

    2002-01-01

    The primary active ingredient of marijuana, 9-tetrahydrocannabinol, exerts its psychoactive effects by binding to cannabinoid CB1 receptors. These receptors are found throughout the brain with high concentrations in the hippocampus and cerebellum. The current study was conducted to evaluate the binding of a newly developed putative cannabinoid antagonist, AM630, and a classical cannabinoid 8-tetrahydrocannabinol as potential PET and/or SPECT imaging agents for brain CB1 receptors. For both of these ligands in vivo and ex vivo studies in mice were conducted. AM630 showed good overall brain uptake (as measure by %IA/g) and a moderately rapid clearance from the brain with a half-clearance time of approximately 30 minutes. However, AM630 did not show selective binding to CB1 cannabinoid receptors. Ex vivo autoradiography supported the lack of selective binding seen in the in vivo study. Similar to AM630, 8-tetrahydrocanibol also failed to show selective binding to CB1 receptor rich brain areas. The 8-tetrahydrocanibol showed moderate overall brain uptake and relatively slow brain clearance as compared to AM630. Further studies were done with AM2233, a cannabinoid ligand with a similar structure as AM630. These studies were done to develop an ex vivo binding assay to quantify the displacement of [131I]AM2233 binding by other ligands in Swiss-Webster and CB1 receptor knockout mice. By developing this assay we hoped to determine the identity of an unknown binding site for AM2233 present in the hippocampus of CB1 knockout mice. Using an approach based on incubation of brain slices prepared from mice given intravenous [131I]AM2233 in either the presence or absence of AM2233 (unlabelled) it was possible to demonstrate a significant AM2233-displacable binding in the Swiss-Webster mice. Future studies will determine if this assay is appropriate for identifying the unknown binding site for AM2233 in the CB1 knockout mice.

  12. Determination of CFTR chloride channel activity and pharmacology using radiotracer flux methods.

    PubMed

    Norez, Caroline; Heda, Ghanshyam D; Jensen, Timothy; Kogan, Ilana; Hughes, Lauren K; Auzanneau, Céline; Dérand, Renaud; Bulteau-Pignoux, Laurence; Li, Canhui; Ramjeesingh, Mohabir; Li, Hongyu; Sheppard, David N; Bear, Christine E; Riordan, John R; Becq, Frédéric

    2004-08-01

    Flux studies using either radioisotopes or ion-selective electrodes are a convenient method to assay the function of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel. Here, we described three different protocols to study the properties, regulation and pharmacology of the CFTR Cl- channel in populations of cells and artificial vesicles. These techniques are widely used to evaluate the function of wild-type and mutant CFTR prior to detailed analyses using the patch-clamp technique. Moreover, they have proved especially valuable in the search for new drugs to treat cystic fibrosis. PMID:15463942

  13. Study of relationships of material properties and high efficiency solar cell performance on material composition

    NASA Astrophysics Data System (ADS)

    Sah, C. T.

    1983-07-01

    The performance improvements obtainable from extending the traditionally thin back-surface-field (BSF) layer deep into the base of silicon solar cells under terrestrial solar illumination (AM1) are analyzed. This extended BSF cell is also known as the back-drift-field cell. About 100 silicon cells were analyzed, each with a different emitter or base dopant impurity distribution whose selection was based on physically anticipated improvements. The four principal performance parameters (the open-circuit voltage, the short-circuit current, the fill factor, and the maximum efficiency) are computed using a FORTRAN program, called Circuit Technique for Semiconductor-device Analysis, CTSA, which numerically solves the six Shockley Equations under AM1 solar illumination at 88.92 mW/cm, at an optimum cell thickness of 50 um. The results show that very significant performance improvements can be realized by extending the BSF layer thickness from 2 um (18% efficiency) to 40 um (20% efficiency).

  14. Study of relationships of material properties and high efficiency solar cell performance on material composition

    NASA Technical Reports Server (NTRS)

    Sah, C. T.

    1983-01-01

    The performance improvements obtainable from extending the traditionally thin back-surface-field (BSF) layer deep into the base of silicon solar cells under terrestrial solar illumination (AM1) are analyzed. This extended BSF cell is also known as the back-drift-field cell. About 100 silicon cells were analyzed, each with a different emitter or base dopant impurity distribution whose selection was based on physically anticipated improvements. The four principal performance parameters (the open-circuit voltage, the short-circuit current, the fill factor, and the maximum efficiency) are computed using a FORTRAN program, called Circuit Technique for Semiconductor-device Analysis, CTSA, which numerically solves the six Shockley Equations under AM1 solar illumination at 88.92 mW/cm, at an optimum cell thickness of 50 um. The results show that very significant performance improvements can be realized by extending the BSF layer thickness from 2 um (18% efficiency) to 40 um (20% efficiency).

  15. Comparative study on the energy efficiency of logic gates based on single-electron transistor technology

    NASA Astrophysics Data System (ADS)

    Choi, Changmin; Lee, Jieun; Park, Sungwook; Chung, In-Young; Kim, Chang-Joon; Park, Byung-Gook; Kim, Dong Myong; Kim, Dae Hwan

    2009-06-01

    The performance and the power consumption of single-electron transistor (SET) technology-based ultra-energy-efficient signal processing circuits are compared based on the SPICE model including non-ideal effects of the experimental data for the first time. In terms of ultra-energy-efficient logic circuits, the binary decision diagram (BDD) logic circuit is the most promising with a dissipated power of 0.29 nW at Vdd = 0.1 V and fin = 50 MHz among the static complementary metal-oxide-semiconductor (CMOS)-like SET logic, the dynamic SET/CMOS hybrid logic, cellular nonlinear network (CNN) and BDD. This result means that the transition of a paradigm substituting the current for the voltage as a state variable of a signal processing is strongly required in post-CMOS signal processing and ultra-energy-efficient applications.

  16. Study on an environmental-friendly and high-efficient fuel cell energy conversion system.

    PubMed

    Yu, Li-Jun; Cao, Guang-Yi; Zhu, Xin-Jian; Jiang, An-Zhong; Tian, Zi-Ping

    2003-01-01

    The kinds and the distribution of the coal in China are investigated. The results indicated that the 80% coal in China is used by the method of the coal gasification. The possibility of utilization and development of the fuel cell power plant in China is analyzed. A combined cycle generation system is designed. Its net electrical efficiency is about 55% (LHV), which is higher than that of the fire power plant. So it is environmental-friendly and high-efficient generation mode. PMID:12602611

  17. Study on structural characteristics of pillared clay modified phosphate fertilizers and its increase efficiency mechanism*

    PubMed Central

    Wu, Ping-xiao; Liao, Zong-wen

    2005-01-01

    Three types of new high-efficiency phosphate fertilizers were made when pillared clays at certain proportions were added into ground phosphate rock. Chemical analyses showed that their soluble phosphorus content decreased more than that of superphosphate. Pot experiment showed that, under equal weights, the new fertilizers increased their efficiency by a large margin over that of superphosphate. Researches on their structures by means of XRD, IR and EPR spectrum revealed that their crystal structures changed considerably, improving their activity and preventing the fixation of available phosphorus in the soil, and consequently, greatly improved the bioavailability and became the main cause of the increase of biomass. PMID:15682504

  18. Loss mechanisms in high-efficiency solar cells: Study of material properties and high-efficiency solar-cell performance on material composition: Project tasks

    NASA Technical Reports Server (NTRS)

    Sah, C. T.

    1985-01-01

    Loss mechanisms in high-efficiency solar cells were discussed. Fundamental limitations and practical solutions were stressed. Present cell efficiency is limited by many recombination sites: emitter, base, contacts, and oxide/silicon interface. Use of polysilicon passivation was suggested. After reduction of these losses, a 25% efficient cell could be built. A floating emitter cell design was shown that had the potential of low recombination losses.

  19. Improving Efficiency and Effectiveness of Training: A Six Year Case Study of Systematic Change.

    ERIC Educational Resources Information Center

    Chevalier, Roger D.

    1990-01-01

    Describes changes in the training system at the U.S. Coast Guard Training Center in Petaluma (CA) that improved the effectiveness and the efficiency of training. Topics discussed include the Instructional Systems Design (ISD) methodology; the process of change; curriculum development; criterion-referenced instruction and testing; cost…

  20. The Role of Awards Programs in Stimulating Energy Efficient Behavior: A Study of Award Winners

    SciTech Connect

    McDermott, Christa; Malone, Elizabeth L.

    2014-07-01

    The value of formal awards programs may be principally in gaining wider recognition for achievements in energy efficiency. But how do these programs contribute to the goal that is presumably behind this value, i.e., stimulating further energy efficient behavior, beyond publicizing the awards ceremonies and describing the projects via websites, posters, and the like? Interviews with 22 individuals and teams of award winners under the Department of Energy Federal Energy Management Program (DOE FEMP) yield insights on the roles that awards programs can play in stimulating energy efficient behavior, especially with regard to institutional dimensions of such behavior. Award winners identified institutional facilitators and barriers in their projects and programs as well as factors in their implementation processes, thus providing information that can guide other efforts. Although only one of the interviewees affirmed that winning an award was a motivating factor, awards do validate often-hard-won achievements through recognition and, in some cases, additional resources, thus stimulating both the winners themselves and those who see the achievements to further energy-saving activities. Finally, award winners’ responses demonstrated the importance of behavioral and institutional change in energy efficiency.

  1. South Carolina School Food Service Programs: A Study To Determine Fiscal Efficiency.

    ERIC Educational Resources Information Center

    Fulmer, Karl E.; Swann, John M.; Taylor, Susan L.

    This report identifies those qualities and characteristics that are usually associated with efficiently and effectively operated school food-service programs. Data were extracted from district audit reports filed with the South Carolina State Department of Education; from the South Carolina Department of Education Office of School Food-services;…

  2. A case study for efficient management of high throughput primary lab data

    PubMed Central

    2011-01-01

    Background In modern life science research it is very important to have an efficient management of high throughput primary lab data. To realise such an efficient management, four main aspects have to be handled: (I) long term storage, (II) security, (III) upload and (IV) retrieval. Findings In this paper we define central requirements for a primary lab data management and discuss aspects of best practices to realise these requirements. As a proof of concept, we introduce a pipeline that has been implemented in order to manage primary lab data at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK). It comprises: (I) a data storage implementation including a Hierarchical Storage Management system, a relational Oracle Database Management System and a BFiler package to store primary lab data and their meta information, (II) the Virtual Private Database (VPD) implementation for the realisation of data security and the LIMS Light application to (III) upload and (IV) retrieve stored primary lab data. Conclusions With the LIMS Light system we have developed a primary data management system which provides an efficient storage system with a Hierarchical Storage Management System and an Oracle relational database. With our VPD Access Control Method we can guarantee the security of the stored primary data. Furthermore the system provides high performance upload and download and efficient retrieval of data. PMID:22005096

  3. Material studies regarding InP-based high-efficiency solar cells

    NASA Astrophysics Data System (ADS)

    Schimper, H.-J.; Kollonitsch, Z.; Möller, K.; Seidel, U.; Bloeck, U.; Schwarzburg, K.; Willig, F.; Hannappel, T.

    2006-01-01

    Aiming at the improvement of the conversion efficiency of a monolithic high-efficiency multi-junction solar cell based on the lattice constant of InP different types of low-band gap n/p solar cells were prepared on the lattice constant of InP via metal organic chemical vapor deposition (MOCVD) using only non-gaseous, so-called alternative precursors like tertiarybutylphosphine (TBP). Employing this less-toxic precursor compared to phosphine an InP single n/p solar cell was prepared as reference yielding the highest internal quantum efficiency reported in the literature. New materials were introduced on the lattice constant of InP, in particular GaAsSb (E=0.75 eV) and InAlGaAs (E=1.03 eV). The new absorber materials were compared to more established materials like InGaAs (E=0.75 eV) and InGaAsP (E=1.03 eV). It will be shown that the latter cell with 18% Al reached an internal quantum efficiency close to that of the InGaAsP cell.

  4. Breakdown of deterministic lateral displacement efficiency for non-dilute suspensions: A numerical study.

    PubMed

    Vernekar, R; Krüger, T

    2015-09-01

    We investigate the effect of particle volume fraction on the efficiency of deterministic lateral displacement (DLD) devices. DLD is a popular passive sorting technique for microfluidic applications. Yet, it has been designed for treating dilute suspensions, and its efficiency for denser samples is not well known. We perform 3D simulations based on the immersed-boundary, lattice-Boltzmann and finite-element methods to model the flow of red blood cells (RBCs) in different DLD devices. We quantify the DLD efficiency in terms of appropriate "failure" probabilities and RBC counts in designated device outlets. Our main result is that the displacement mode breaks down upon an increase of RBC volume fraction, while the zigzag mode remains relatively robust. This suggests that the separation of larger particles (such as white blood cells) from a dense RBC background is simpler than separating smaller particles (such as platelets) from the same background. The observed breakdown stems from non-deterministic particle collisions interfering with the designed deterministic nature of DLD devices. Therefore, we postulate that dense suspension effects generally hamper efficient particle separation in devices based on deterministic principles. PMID:26143149

  5. Single Wall Diesel Particulate Filter (DPF) Filtration Efficiency Studies Using Laboratory Generated Particles

    SciTech Connect

    Yang, Juan; Stewart, Marc; Maupin, Gary D.; Herling, Darrell R.; Zelenyuk, Alla

    2009-04-15

    Diesel offers higher fuel efficiency, but produces higher exhaust particulate matter. Diesel particulate filters are presently the most efficient means to reduce these emissions. These filters typically trap particles in two basic modes: at the beginning of the exposure cycle the particles are captured in the filter holes, and at longer times the particles form a "cake" on which particles are trapped. Eventually the "cake" removed by oxidation and the cycle is repeated. We have investigated the properties and behavior of two commonly used filters: silicon carbide (SiC) and cordierite (DuraTrap® RC) by exposing them to nearly-spherical ammonium sulfate particles. We show that the transition from deep bed filtration to "cake" filtration can easily be identified by recording the change in pressure across the filters as a function of exposure. We investigated performance of these filters as a function of flow rate and particle size. The filters trap small and large particles more efficiently than particles that are ~80 to 200 nm in aerodynamic diameter. A comparison between the experimental data and a simulation using incompressible lattice-Boltzmann model shows very good qualitative agreement, but the model overpredicts the filter’s trapping efficiency.

  6. Numerical study on the influence of boss cap fins on efficiency of controllable-pitch propeller

    NASA Astrophysics Data System (ADS)

    Xiong, Ying; Wang, Zhanzhi; Qi, Wanjiang

    2013-03-01

    Numerical simulation is investigated to disclose how propeller boss cap fins (PBCF) operate utilizing Reynolds-averaged Navier-Stokes (RANS) method. In addition, exploration of the influencing mechanism of PBCF on the open water efficiency of one controllable-pitch propeller is analyzed through the open water characteristic curves, blade surface pressure distribution and hub streamline distribution. On this basis, the influence of parameters including airfoil profile, diameter, axial position of installation and circumferential installation angle on the open water efficiency of the controllable-pitch propeller is investigated. Numerical results show: for the controllable-pitch propeller, the thrust generated is at the optimum when the radius of boss cap fins is 1.5 times of propeller hub with an optimal installation position in the axial direction, and its optimal circumferential installation position is the midpoint of the extension line of the front and back ends of two adjacent propeller roots in the front of fin root. Under these optimal parameters, the gain of open water efficiency of the controllable-pitch propeller with different advance velocity coefficients is greater than 0.01, which accounts for approximately an increase of 1%-5% of open water efficiency.

  7. Study of Core Competency Elements and Factors Affecting Performance Efficiency of Government Teachers in Northeastern Thailand

    ERIC Educational Resources Information Center

    Chansirisira, Pacharawit

    2012-01-01

    The research aimed to investigate the core competency elements and the factors affecting the performance efficiency of the civil service teachers in the northeastern region, Thailand. The research procedure consisted of two steps. In the first step, the data were collected using a questionnaire with the reliability (Cronbach's Alpha) of 0.90. The…

  8. Efficient use of historical data for genomic selection: a case study of rust resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic selection (GS) is a new methodology that can improve wheat breeding efficiency. To implement GS, a training population (TP) with both phenotypic and genotypic data is required to train a statistical model used to predict genotyped selection candidates (SCs). Several factors impact prediction...

  9. A model study of the efficiency of the Asp-His-Ser triad.

    PubMed

    Lankau, Timm; Yu, Chin-Hui

    2010-07-15

    The observation of the Asp-His-Ser triad (Asp: aspartate, His: histidine, Ser: serine) triad both in mammalian and bacterial proteases suggests a special efficiency. A series of B3LYP/D95*(d,p) calculations on various [X-H(beta)Y](-) dyads (as part of the [X-H(beta)Y-H(alpha)Ac](-) model triad, HAc: acetic acid) made from eight different anions X(-) and 15 different coupling elements H(beta)Y was done to analyze the molecular origin of this efficiency. The X(-) anion acts merely as an electron density donor independent of its chemical nature, and the evolutionary selection of Asp for the catalytic triad therefore seems to be caused by the pH of the triads environment. As the linking proton H(beta) moves from Y(-) to X(-), electron density is effectively moved from X(-) to Y(-) thereby increasing the proton affinity (PA) of the [X-HY](-) dyad, which finally leads to the deprotonization of the HAc molecule. The degree to which the position of H(alpha) controls the PA is dominantly determined by the coupling element HY. The model calculations indicate that 4-methyl-1H-imidazole (HMim) is a very efficient coupling element, which suggest that the evolutionary convergence to the Asp-His-Ser is not only controlled by the ready availability of the imidazole motive in His but also by its high efficiency. PMID:20082386

  10. Genome-wide association study of reproductive efficiency in female cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reproductive efficiency is of economic importance in commercial beef cattle production, as failure to achieve pregnancy reduces the number of calves marketed per cow exposed to breeding. Identification of genetic markers with predictive merit for reproductive success would facilitate accurate predic...

  11. Flock Foraging Efficiency in Relation to Food Sensing Ability and Distribution: a Simulation Study

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee

    2013-08-01

    Flocking may be an advantageous strategy for acquiring food resources. The degree of advantage is related to two factors: the ability of flock members to detect food resources and patterns of food distribution in the environment. To understand foraging efficiency as a function of these factors, I constructed a two-dimensional (2D) flocking model incorporating the two factors. At the start of the simulation, food particles were heterogeneously distributed. The heterogeneity, H, was characterized as a value ranging from 0.0 to 1.0. For each flock member, food sensing ability was defined by two variables: sensing distance, R and sensing angle, θ. Foraging efficiency of a flock was defined as the time, τ, required for a flock to consume all the available food resources. Simulation results showed that flock foraging is most efficient when individuals had an intermediate sensing ability (R = 60), but decreased for low (R < 60) and high (R > 60) sensing ability. When R > 60, patterns in foraging efficiency with increasing sensing distance and food resource aggregation were less consistent. This inconsistency was due to instability of the flock and a higher rate of individuals failing to capture target food resources. In addition, I briefly discuss the benefits obtained by foraging in flocks from an evolutionary perspective.

  12. Study on Design Standard of Distribution Transformers considering Economic Efficiency and CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Yamada, Tomoyuki; Takagi, Masaaki; Yamamoto, Hiromi; Yamaji, Kenji

    No load loss of amorphous transformer (i.e. amorphous metal-based transformer) could be reduced by about 70% compared with traditional transformers (e.g. silicon steel-based transformer). Amorphous transformers have the potential to realize large amount of energy savings and reduction of CO2. However, amorphous transformers have disadvantages of high initial costs and high load loss parameters compared with traditional transformers. In Japan, JIS (Japanese industrial standards) set two regulations about efficiencies of transformers. One is a regulation about amount of total loss at equivalent load factor Pe = 40%, which is made to improve efficiency in actual usage. The other is a regulation about efficiency of rated load (Pe = 100%). Authors propose an optimal design of transformers considering trade-off between the material cost and power loss cost with taking into account the standard in the rated load. Economies of transformers are evaluated in the paper by the sum of the initial cost and the power loss cost. Simulation results show that the two regulations about efficiency of JIS are not reasonable. If there were not the regulation in the rated load, we could design low initial cost and environmentally compatible transformers.

  13. Dosimetry of exendin-4 based radiotracer for glucagonlike peptide-1 receptor imaging: an initial report

    NASA Astrophysics Data System (ADS)

    Tomaszuk, M.; Sowa-Staszczak, A.; Lenda-Tracz, W.; Glowa, B.; Pach, D.; Buziak-Bereza, M.; Stefanska, A.; Janota, B.; Pawlak, D.; Mikolajczak, R.; Hubalewska-Dydejczyk, A. B.

    2011-09-01

    Overexpression of glucagonlike peptide-1 (GLP-1) receptors in human tumours is a potential target for future imaging and therapy. The GLP-1 receptor imaging using [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 could be useful in the localization of unknown insulinoma focus. The aim of this study was to present the first experience of our unit with the new radiopharmaceutical and its dose estimates. Imaging studies and dose assessment, according to the MIRD schema and MIRD Pamphlet No.11, were performed for 3 patients (2 with suspicion of insulinoma, 1 with suspected insulinoma recurrence). In the first case suspicion of insulinoma was not confirmed. In the second case localized accumulation of tracer in the pancreas was removed by surgery and the clinical symptoms of insulinoma receded. In the third case, pathological accumulation of tracer was localized and recurrence of insulinoma was confirmed in fusion with CT images. The biological half-time did not exceed 2.7.h. The effective half-time did not exceed 4.8 h. The total-body radiation dose did not exceed 0.0038 mGy/MBq and is comparable with the radiation dose to patient after somatostatin receptor scintigraphy. The highest radiation dose was calculated for kidneys (~ 0.070 mGy/MBq). [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 is a good candidate for clinical GLP-1 receptor imaging studies and appears safe for the patient from radiological safety point of view.

  14. Efficient nitrogen recycling through sustainable use of organic wastes in agriculture - an Australian case study

    NASA Astrophysics Data System (ADS)

    Rigby, Hannah; Landman, Michael; Collins, David; Walton, Katrina; Penney, Nancy; Pritchard, Deborah

    2014-05-01

    The effective recycling of nutrients in treated sewage sludge (biosolids) domestic (e.g. source separated food waste), agricultural, and commercial and industrial (C&I) biowastes (e.g. food industry wastes, papermill sludge) for use on land, generally following treatment (e.g. composting, anaerobic digestion or thermal conversion technologies) as alternatives to conventional mineral fertilisers in Australia can have economic benefits, ensure food security, and close the nutrient loop. In excess of 75% of Australian agricultural soils have less than 1% organic matter (OM), and, with 40 million tonnes of solid waste per year potentially available as a source of OM, biowastes also build soil carbon (C) stocks that improve soil structure, fertility and productivity, and enhance soil ecosystem services. In recent years, the increasing cost of conventional mineral fertilisers, combined with changing weather patterns have placed additional pressure on regional and rural communities. Nitrogen (N) is generally the most limiting nutrient to crop production, and the high-energy required and GHGs associated with its manufacture mean that, additionally, it is critical to use N efficiently and recycle N resources where possible. Biosolids and biowastes have highly variable organic matter (OM) and nutrient contents, with N often present in a variety of forms only some of which are plant-available. The N value is further influenced by treatment process, storage and fundamental soil processes. The correct management of N in biowastes is essential to reduce environmental losses through leaching or runoff and negative impacts on drinking water sources and aquatic ecosystems. Gaseous N emissions also impact upon atmospheric quality and climate change. Despite the body of work to investigate N supply from biosolids, recent findings indicate that historic and current management of agricultural applications of N from biosolids and biowastes in Australia may still be inefficient leading

  15. Water uptake efficiency of a maize plant - A simulation case study

    NASA Astrophysics Data System (ADS)

    Meunier, Félicien; Leitner, Daniel; Bodner, Gernot; Javaux, Mathieu; Schnepf, Andrea

    2014-05-01

    Water uptake by plant roots is a complex mechanism controlled by biological and physical properties of the soil-plant-atmosphere system and affects a major component of the water cycle, transpiration. This uptake of water by plants is one of the major factors of plant development. Since water uptake occurs at the roots, root architecture and hydraulic properties both play a crucial role in plant productivity. A fundamental understanding of the main processes of water uptake will enable better breeding of drought resistant plants and the improvement of irrigation strategies. In this work we analyzed the differences of root water uptake between idealized genotypes of a plant using mathematical modelling The numerical simulations were performed by the R-SWMS software (Javaux et al., 2008). The model describes 3-D water movement in soil by solving Richard's equation with a sink term representing root uptake. Water flow within the root xylem network and between soil and root is modelled based on water pressure gradients and calculated according to Doussan's model. The sink term is calculated by integration of local uptakes within rooted representative elementary volumes of soil. The plant water demand is described by a boundary condition at the base of the shoot. We compare the water uptake efficiency of three types of root system architectures of a maize plant. Two are actual architectures from genotypes showing significant differences regarding the internodal distance, the root growth rate and the insertion angle of their primary roots. The third one is an ideotype according to Lynch of the maize plant designed to perform better in one dry environment. We generated with RootBox five repetitions of these three root systems with the same total root volume and simulated two drought scenarios at the flowering stage (lack of water at the top or at the bottom of the soil domain). We did these simulations for two distinct distributions of local conductivities of root

  16. First-pass cerebral extraction of benzamide-derivative radiotracers for SPECT.

    PubMed

    Bottoncetti, A; Pupi, A; Sestini, S; Pecorale, A; Raspanti, S; Meldolesi, U

    1998-04-01

    Central dopaminergic receptors are widely studied for their importance in the pathophysiology of neurological and psychiatric diseases. We have investigated the cerebral delivery kinetics of three dopaminergic ligands in rats through the use of an indicator fractionation method to measure the tracer's regional influx rate constant with respect to regional blood flow. The aim is to collect the in vivo kinetic parameters of the radioligand cerebral distribution, which are necessary if, dealing with SPECT and "trapped" tracers, one wishes to analyse data using a graphical approach. PMID:9620635

  17. Elucidating genetic diversity among sour orange rootstocks: a comparative study of the efficiency of RAPD and SSR markers.

    PubMed

    Lamine, Myriam; Mliki, Ahmed

    2015-03-01

    In order to compare the effectiveness of two molecular marker systems, a set of six RAPD and nine SSR markers were used to study the genetic diversity in a population of 46 sour orange accessions, a common rootstock used in almost all citrus orchards in Tunisia. Genetic diversity parameters [average and effective number of alleles, percentage of polymorphism, polymorphic information content (PIC), effective marker index (EMI), and marker index (MI) parameters] for RAPD, SSR, and RAPD + SSR were determined in order to assess the efficiency of the two marker systems. The results revealed that these parameters were significantly higher when using RAPD markers. Similarly, cluster analysis using the results of RAPD was practically the same as that obtained when combining data from the two marker systems (RAPD + SSR) demonstrating the efficiency of RAPD in discriminating between sour orange accessions. Therefore, the use of SSR markers, known to be more efficient and discriminatory, does not bring significant supplementary information in this work. Indeed, results would have been obtained using only the RAPD markers. Accordingly, this work highlights the efficiency and advantages of RAPD, as an easy and efficient technique, in studying citrus rootstock's genetic diversity, and establishing genetic relationships among citrus accessions. PMID:25586488

  18. Synthesis and evaluation of novel serotonin 4 receptor radiotracers for single photon emission computed tomography.

    PubMed

    Lalut, Julien; Tournier, Benjamin B; Cailly, Thomas; Lecoutey, Cédric; Corvaisier, Sophie; Davis, Audrey; Ballandonne, Céline; Since, Marc; Millet, Philippe; Fabis, Frédéric; Dallemagne, Patrick; Rochais, Christophe

    2016-06-30

    Despite its implication in several physiological and pathological processes the serotonin subtype-4 receptor (5-HT4R) has seen limited effort for the development of radiolabeling agent especially concerning single photon emission computed tomography (SPECT). Bearing an ester function, the available ligands are rapidly susceptible to hydrolysis which limits their use in vivo. In this study the synthesis of iodinated benzamide and ketone analogs were described. Their affinity for the 5-HT4R and their lipophilicity were evaluated and the most promising derivatives were evaluated ex vivo for their binding to the receptor and for their ability to displace the reference ligand [(125)I]-SB207710. PMID:27060761

  19. Marine anthropogenic radiotracers in the Southern Hemisphere: New sampling and analytical strategies

    NASA Astrophysics Data System (ADS)

    Levy, I.; Povinec, P. P.; Aoyama, M.; Hirose, K.; Sanchez-Cabeza, J. A.; Comanducci, J.-F.; Gastaud, J.; Eriksson, M.; Hamajima, Y.; Kim, C. S.; Komura, K.; Osvath, I.; Roos, P.; Yim, S. A.

    2011-04-01

    The Japan Agency for Marine Earth Science and Technology conducted in 2003-2004 the Blue Earth Global Expedition (BEAGLE2003) around the Southern Hemisphere Oceans, which was a rare opportunity to collect many seawater samples for anthropogenic radionuclide studies. We describe here sampling and analytical methodologies based on radiochemical separations of Cs and Pu from seawater, as well as radiometric and mass spectrometry measurements. Several laboratories took part in radionuclide analyses using different techniques. The intercomparison exercises and analyses of certified reference materials showed a reasonable agreement between the participating laboratories. The obtained data on the distribution of 137Cs and plutonium isotopes in seawater represent the most comprehensive results available for the Southern Hemisphere Oceans.

  20. A DEVELOPMENTAL STUDY OF THE RELATIONSHIP BETWEEN REACTION-TIME AND PROBLEM-SOLVING EFFICIENCY. FINAL REPORT.

    ERIC Educational Resources Information Center

    FRIEDMAN, STANLEY R.

    MANY STUDIES HAVE INDICATED THE PRESENCE OF A SLUMP OR INVERSION IN THE PROBLEM-SOLVING EFFICIENCY OF CHILDREN AT THE FOURTH GRADE LEVEL. IT HAS BEEN SUGGESTED THAT THIS MAY BE DUE TO THE INTERFERING EFFECT OF THE FORMATION OF COMPLEX HYPOTHESES BY THE CHILDREN. SINCE A TENDENCY TO RESPOND RAPIDLY WOULD PRESUMABLY INHIBIT THE FORMATION OF COMPLEX…

  1. Identification of ABC Transporter Interaction of a Novel Cyanoquinoline Radiotracer and Implications for Tumour Imaging by Positron Emission Tomography

    PubMed Central

    Slade, Rozanna L.; Pisaneschi, Federica; Nguyen, Quang-De; Smith, Graham; Carroll, Laurence; Beckley, Alice; Kaliszczak, Maciej A.; Aboagye, Eric O.

    2016-01-01

    Background The epidermal growth factor receptor (EGFR) is overexpressed in many cancers including lung, ovarian, breast, head and neck and brain. Mutation of this receptor has been shown to play a crucial role in the response of non-small cell lung carcinoma (NSCLC) to EGFR-targeted therapies. It is envisaged that imaging of EGFR using positron emission tomography (PET) could aid in selection of patients for treatment with novel inhibitors. We recognised multi-drug resistant phenotype as a threat to development of successful imaging agents. In this report, we describe discovery of a novel cyanoquinoline radiotracer that lacks ABC transporter activity. Methods Cellular retention of the prototype cyanoquinoline [18F](2E)-N-{4-[(3-chloro-4-fluorophenyl)amino]-3-cyano-7-ethoxyquinolin-6-yl}-4-({[1-(2-fluoroethyl)-1H-1,2,3-triazol-4-yl]methyl}amino)-but-2-enamide ([18F]FED6) and [18F](2E)-N-{4-[(3-chloro-4-fluorophenyl)amino]-3-cyano-7-ethoxyquinolin-6-yl}-4-[({1-[(2R,5S)-3-fluoro-4,5-dihydroxy-6-(hydroxymethyl)oxan-2-yl]-1H-1,2,3-triazol-4-yl}methyl)amino]but-2-enamide ([18F]FED20) were evaluated to establish potential for imaging specificity. The substrate specificity of a number of cyanoquinolines towards ABC transporters was investigated in cell lines proficient or deficient in ABCB1 or ABCG2. Results FED6 demonstrated substrate specificity for both ABCG2 and ABCB1, a property that was not observed for all cyanoquinolines tested, suggesting scope for designing novel probes. ABC transporter activity was confirmed by attenuating the activity of transporters with drug inhibitors or siRNA. We synthesized a more hydrophilic compound [18F]FED20 to overcome ABC transporter activity. FED20 lacked substrate specificity for both ABCB1 and ABCG2, and maintained a strong affinity for EGFR. Furthermore, FED20 showed higher inhibitory affinity for active mutant EGFR versus wild-type or resistant mutant EGFR; this property resulted in higher [18F]FED20 cellular retention in active

  2. Tissue biodistribution and blood clearance rates of intravenously administered carbon nanotube radiotracers

    NASA Astrophysics Data System (ADS)

    Singh, Ravi; Pantarotto, Davide; Lacerda, Lara; Pastorin, Giorgia; Klumpp, Cédric; Prato, Maurizio; Bianco, Alberto; Kostarelos, Kostas

    2006-02-01

    Carbon nanotubes (CNT) are intensively being developed for biomedical applications including drug and gene delivery. Although all possible clinical applications will require compatibility of CNT with the biological milieu, their in vivo capabilities and limitations have not yet been explored. In this work, water-soluble, single-walled CNT (SWNT) have been functionalized with the chelating molecule diethylentriaminepentaacetic (DTPA) and labeled with indium (111In) for imaging purposes. Intravenous (i.v.) administration of these functionalized SWNT (f-SWNT) followed by radioactivity tracing using gamma scintigraphy indicated that f-SWNT are not retained in any of the reticuloendothelial system organs (liver or spleen) and are rapidly cleared from systemic blood circulation through the renal excretion route. The observed rapid blood clearance and half-life (3 h) of f-SWNT has major implications for all potential clinical uses of CNT. Moreover, urine excretion studies using both f-SWNT and functionalized multiwalled CNT followed by electron microscopy analysis of urine samples revealed that both types of nanotubes were excreted as intact nanotubes. This work describes the pharmacokinetic parameters of i.v. administered functionalized CNT relevant for various therapeutic and diagnostic applications. nanomedicine | blood circulation half-life | drug delivery | pharmacokinetics | nanotoxicology

  3. Toward the Optimization of Bombesin-Based Radiotracers for Tumor Targeting.

    PubMed

    Valverde, Ibai E; Vomstein, Sandra; Mindt, Thomas L

    2016-04-28

    The peptide bombesin (BBN) is a peptide with high affinity for the gastrin-releasing peptide receptor (GRPr), a receptor that is overexpressed by, for example, breast and prostate cancers. Thus, GRPr agonists can be used as cancer-targeting vectors to shuttle diagnostic and therapeutic agents into tumor cells. With the aim of optimizing the tumor targeting properties of a radiolabeled [Nle(14)]BBN(7-14) moiety, novel BBN(7-14)- and BBN(6-14)-based radioconjugates were synthesized, labeled with Lu-177, and fully evaluated in vitro and in vivo. The effect of residue and backbone modification on several parameters such as the internalization of the radiolabeled peptides into PC3 and AR42J tumor cells, their affinity toward the human GRPr, metabolic stability in blood plasma, and biodistribution in mice bearing GRPr-expressing PC3 xenografts was studied. As a result of our investigations, a novel radiolabeled GRPr agonist with a high tumor uptake and a high tumor-to-kidney ratio was identified. PMID:27054526

  4. Comparison of three high affinity SPECT radiotracers for the dopamine D2 receptor.

    PubMed

    al-Tikriti, M S; Baldwin, R M; Zea-Ponce, Y; Sybirska, E; Zoghbi, S S; Laruelle, M; Malison, R T; Kung, H F; Kessler, R M; Charney, D S

    1994-02-01

    The regional brain distribution and pharmacological specificity of three high affinity tracers for the dopamine (DA) D2 receptor: [123I]IBF, [123I]epidepride, and [123I]2'-ISP were assessed by SPECT imaging of non-human primates. The ratios of striatal-to-occipital activities at the time of peak striatal uptake were 2.2, 6.3 and 1.7, respectively. From the peak striatal activities, washout rates were 33, 4 and 16%/h for [123I]IBF, [123I]epidepride and [123I]2'-ISP, respectively. The reversibility of the striatal uptake of all three agents was demonstrated by the rapid displacement induced by the dopamine D2 selective antipsychotic agent raclopride, which increased washout rates to 96, 58 and 43%/h. The administration of d-amphetamine, which induces release of dopamine, had no noticeable effect on [123I]epidepride but increased the washout rate of [123I]IBF. These results suggest that, among these three agents, [123I]epidepride is the superior tracer for in vivo displacement studies because of its slow washout and high target-to-background ratios. However, for tracer kinetic modeling, [123I]IBF may be the superior agent because of its early time of peak uptake and its higher target-to-background ratios than [123I]2'-ISP. PMID:9234281

  5. Impact of D2 Receptor Internalization on Binding Affinity of Neuroimaging Radiotracers

    PubMed Central

    Guo, Ningning; Guo, Wen; Kralikova, Michaela; Jiang, Man; Schieren, Ira; Narendran, Raj; Slifstein, Mark; Abi-Dargham, Anissa; Laruelle, Marc; Javitch, Jonathan A; Rayport, Stephen

    2010-01-01

    Synaptic dopamine (DA) levels seem to affect the in vivo binding of many D2 receptor radioligands. Thus, release of endogenous DA induced by the administration of amphetamine decreases ligand binding, whereas DA depletion increases binding. This is generally thought to be due to competition between endogenous DA and the radioligands for D2 receptors. However, the temporal discrepancy between amphetamine-induced increases in DA as measured by microdialysis, which last on the order of 2 h, and the prolonged decrease in ligand binding, which lasts up to a day, has suggested that agonist-induced D2 receptor internalization may contribute to the sustained decrease in D2 receptor-binding potential seen following a DA surge. To test this hypothesis, we developed an in vitro system showing robust agonist-induced D2 receptor internalization following treatment with the agonist quinpirole. Human embryonic kidney 293 (HEK293) cells were stably co-transfected with human D2 receptor, G-protein-coupled receptor kinase 2 and arrestin 3. Agonist-induced D2 receptor internalization was demonstrated by fluorescence microscopy, flow cytometry, and radioligand competition binding. The binding of seven D2 antagonists and four agonists to the surface and internalized receptors was measured in intact cells. All the imaging ligands bound with high affinity to both surface and internalized D2 receptors. Affinity of most of the ligands to internalized receptors was modestly lower, indicating that internalization would reduce the binding potential measured in imaging studies carried out with these ligands. However, between-ligand differences in the magnitude of the internalization-associated affinity shift only partly accounted for the data obtained in neuroimaging experiments, suggesting the involvement of mechanisms beyond competition and internalization. PMID:19956086

  6. Efficient and selective isotopic labeling of hemes to facilitate the study of multiheme proteins

    SciTech Connect

    Fonseca, Bruno M.; Tien, Ming; Rivera, Mario; Shi, Liang; Louro, Ricardo O.

    2012-04-02

    Specific isotopic labeling of hemes provides a unique opportunity to characterize the structure and function of heme-proteins. Unfortunately, present day methods do not allow efficient labeling in high yields of multiheme cytochromes c, which are of great biotechnological interest. Here, a method for production of recombinant multiheme cytochromes c in Escherichia coli with isotopically labeled hemes is reported. A small tetraheme cytochrome of 12 kDa from Shewanella oneidensis MR-1 was used to demonstrate the method, achieving a production of 4 mg of pure protein per liter. This method achieves, in a single step, efficient expression and incorporation of hemes isotopically labeled in specific atom positions adequate for spectroscopic characterization of these complex heme proteins. It is, furthermore, of general application to heme proteins opening new possibilities in the characterization of this important class of proteins.

  7. A Comprehensive Study on Energy Efficiency and Performance of Flash-based SSD

    SciTech Connect

    Park, Seon-Yeon; Kim, Youngjae; Urgaonkar, Bhuvan; Lee, Joonwon; Seo, Euiseong

    2011-01-01

    Use of flash memory as a storage medium is becoming popular in diverse computing environments. However, because of differences in interface, flash memory requires a hard-disk-emulation layer, called FTL (flash translation layer). Although the FTL enables flash memory storages to replace conventional hard disks, it induces significant computational and space overhead. Despite the low power consumption of flash memory, this overhead leads to significant power consumption in an overall storage system. In this paper, we analyze the characteristics of flash-based storage devices from the viewpoint of power consumption and energy efficiency by using various methodologies. First, we utilize simulation to investigate the interior operation of flash-based storage of flash-based storages. Subsequently, we measure the performance and energy efficiency of commodity flash-based SSDs by using microbenchmarks to identify the block-device level characteristics and macrobenchmarks to reveal their filesystem level characteristics.

  8. CO2 dissociation in an atmospheric pressure plasma/catalyst system: a study of efficiency

    NASA Astrophysics Data System (ADS)

    Spencer, L. F.; Gallimore, A. D.

    2013-02-01

    The continual and increasing use of fossil fuels throughout the world has advanced concerns of atmospheric carbon dioxide (CO2) concentrations, causing a swell of scientific interest to ease the predicted effects of global warming. This work experimentally investigates the conversion of CO2 to carbon monoxide (CO) and oxygen in an atmospheric pressure microwave plasma/catalyst system. Diagnostics such as mass spectrometry and optical emission spectroscopy are used to identify the gas species present after plasma treatment and to measure plasma temperatures. The CO2 gas is first treated with plasma alone, and is then treated with a combination of plasma and rhodium (Rh) catalyst material. While the plasma system alone is able to achieve a 20% energy efficiency, the Rh catalyst actually causes a drop in efficiency due to reverse reactions occurring on the surface. The plasma temperature measurements indicate thermal equilibrium between Tr and Tv around 6000-7000 K.

  9. Final Technical Report "Study of Efficiency of Raman Backscattering Amplification in Plasma"

    SciTech Connect

    Suckewer, Szymon

    2014-03-31

    General : Our major scientific achievements in Raman Backscattering (RBS) amplification and compression of short laser pulses in plasma. The laser system based on RBS steps in where the current technology of chirped pulse amplification (CPA) (extremely successful in developing ultra-short and ultra-intense laser pulses in last 2 decades) becomes difficult and very expensive to apply. Good base for such RBS laser was created by our recent experiments, which were supported by GPS grants. The main objective of the present grant was: improvement efficiency of energy transfer from pump to seed. The results surpassed our expectations; we improved the efficiency of energy transfer from pump to seed by a factor of 6 compared to the best of our previous results and amplified seed pulse compressed down to about 50 fsec.

  10. A Study For Efficiently Solving Optimisation Problems With An Increasing Number Of Design Variables

    SciTech Connect

    Trichon, S.; Ponthot, J.-P.; Bonte, M. H. A.; Boogaard, A. H. van den

    2007-05-17

    Coupling optimisation algorithms to Finite Element Methods (FEM) is a very promising way to achieve optimal metal forming processes. However, many optimisation algorithms exist and it is not clear which of these algorithms to use. This paper investigates the sensitivity of a Sequential Approximate Optimisation algorithm (SAO) proposed to an increasing number of design variables and compares it with two other algorithms: an Evolutionary Strategy (ES) and an Evolutionary version of the SAO (ESAO). In addition, it observes the influence of different Designs Of Experiments used with the SAO. It is concluded that the SAO is very capable and efficient and its combination with an ES is not beneficial. Moreover, the use of SAO with Fractional Factorial Design is the most efficient method, rather than Full Factorial Design as proposed.

  11. A parametric study of the destruction efficiency of Bacillus spores in low pressure oxygen-based plasmas.

    PubMed

    Hury, S; Vidal, D R; Desor, F; Pelletier, J; Lagarde, T

    1998-06-01

    The destruction of Bacillus spores in oxygen-based plasmas sustained in the millitorr pressure range has been studied as functions of various biological and plasma parameters, namely Bacillus species, surface concentration of spores, treatment temperature, and gas composition. In an oxygen plasma, Bacillus stearothermophilus appears less plasma-resistant than the other spores tested. Oxygen, H2O2 and chiefly CO2 plasmas are clearly shown to be much more efficient in destroying Bacillus subtilis spores than pure argon plasma. The bacterial surface concentration on the spore carriers and the treatment temperature also lead to significant variations in the destruction efficiency of spores when using CO2 plasma. PMID:9717311

  12. A Study on Efficient Mobile IPv6 Fast Handover Scheme Using Reverse Binding Mechanism

    NASA Astrophysics Data System (ADS)

    Tolentino, Randy S.; Lee, Kijeong; Kim, Sung-Gyu; Kim, Miso; Park, Byungjoo

    This paper proposes a solution for solving the packet handover issues of MIPv6. We propose an efficient scheme that can support fast handover effectively in standard Mobile IPv6 (MIPv6) by optimizing the associated data and the flow of signal during handover. A new signaling message Reverse Packet Binding Mechanism is defined and utilized to hasten the handover procedure by adding a buffer in access point (AP) and home agent (HA).

  13. A scoping study on energy-efficiency market transformation by California Utility DSM Programs

    SciTech Connect

    Eto, J.; Prahl, R.; Schlegel, J.

    1996-07-01

    Market transformation has emerged as a central policy objective for future publicly-funded energy-efficiency programs in California. California Public Utilities Commission (CPUC) Decision 95-12-063 calls for public funding to shift to activities designed to transform the energy-efficiency market. The CPUC envisions that funding {open_quotes}would only be needed for specific and limited periods of time to cause the market to be transformed{close_quotes}. At the same time, the CPUC also acknowledges that {open_quotes}there are many definitions of market transformation{close_quotes} ... and does {open_quotes}not attempt to refine those definitions today{close_quotes}. We argue that a definition of market transformation is essential. The literature is now replete with definitions, and an operational definition is needed for the CPUC to decide on which programs should be supported with public funds. The CPUC decision initially indicated a preference for programs that do not provide financial assistance 4-efficiency programs that rely on financial assistance to customers. However, energy customers have traditionally accounted for a substantial portion of California utility`s DSM programs, so the CPUC`s direction to use ratepayer funds to support programs that will transform the market raises critical questions about how to analyze what has happened in order to plan effectively for the future: Which utility energy-efficiency programs, including those that provide financial assistance to customers, have had market transforming effects? To what extent do current regulatory rules and practices encourage or discourage utilities from running programs that are designed to transform the market? Should the rules and programs be modified, and, if so, how, to promote market transformation?

  14. A stochastic frontier approach to study the relationship between gastrointestinal nematode infections and technical efficiency of dairy farms.

    PubMed

    van der Voort, Mariska; Van Meensel, Jef; Lauwers, Ludwig; Vercruysse, Jozef; Van Huylenbroeck, Guido; Charlier, Johannes

    2014-01-01

    The impact of gastrointestinal (GI) nematode infections in dairy farming has traditionally been assessed using partial productivity indicators. But such approaches ignore the impact of infection on the performance of the whole farm. In this study, efficiency analysis was used to study the association of the GI nematode Ostertagia ostertagi on the technical efficiency of dairy farms. Five years of accountancy data were linked to GI nematode infection data gained from a longitudinal parasitic monitoring campaign. The level of exposure to GI nematodes was based on bulk-tank milk ELISA tests, which measure the antibodies to O. ostertagi and was expressed as an optical density ratio (ODR). Two unbalanced data panels were created for the period 2006 to 2010. The first data panel contained 198 observations from the Belgian Farm Accountancy Data Network (Brussels, Belgium) and the second contained 622 observations from the Boerenbond Flemish farmers' union (Leuven, Belgium) accountancy system (Tiber Farm Accounting System). We used the stochastic frontier analysis approach and defined inefficiency effect models specified with the Cobb-Douglas and transcendental logarithmic (Translog) functional form. To assess the efficiency scores, milk production was considered as the main output variable. Six input variables were used: concentrates, roughage, pasture, number of dairy cows, animal health costs, and labor. The ODR of each individual farm served as an explanatory variable of inefficiency. An increase in the level of exposure to GI nematodes was associated with a decrease in technical efficiency. Exposure to GI nematodes constrains the productivity of pasture, health, and labor but does not cause inefficiency in the use of concentrates, roughage, and dairy cows. Lowering the level of infection in the interquartile range (0.271 ODR) was associated with an average milk production increase of 27, 19, and 9L/cow per year for Farm Accountancy Data Network farms and 63, 49, and

  15. Redox conditions and the efficiency of chlorinated ethene biodegradation: Field studies

    USGS Publications Warehouse

    Chapelle, F.H.; Bradley, P.M.

    2000-01-01

    The effect of redox conditions on the efficiency of chlorinated ethene biodegradation was investigated at two field sites. One site (NAS Cecil Field, FL) is characterized by predominantly Fe(III)-reducing conditions in the contaminant source area, grading to predominantly sulfate- reducing conditions downgradient. This sequence of redox conditions led to relatively inefficient biodegradation of chlorinated ethenes, with high concentrations of trichloroethene extending more than 400 meters downgradient of the source area. In contrast, a second site (NBS Kings Bay, GA) characterized by predominantly sulfate-reducing conditions in the source area followed by Fe(III)-reducing conditions downgradient. In this system perchloroethene (PCE) and TCE were rapidly biodegraded and extended less than 100 meters downgradient. Rates of ground- water transport are similar at the two sites (???0.2 m/d) indicating that the succession of redox processes, rather than other hydrologic factors, is the principal control on biodegradation. In particular, redox conditions that favor the initial reduction of highly chlorinated ethenes (methanogenic or sulfate-reducing conditions) followed by more oxidizing conditions (Fe(III)- reducing or oxic conditions) favors efficient biodegradation. Thus, documenting the succession of redox processes is an important step in understanding the efficiency of chlorinated ethene biodegradation in ground-water systems.

  16. Electronic and thermal transport study of sinusoidally corrugated nanowires aiming to improve thermoelectric efficiency.

    PubMed

    Park, K H; Martin, P N; Ravaioli, U

    2016-01-22

    Improvement of thermoelectric efficiency has been very challenging in the solid-state industry due to the interplay among transport coefficients which measure the efficiency. In this work, we modulate the geometry of nanowires to interrupt thermal transport with causing only a minimal impact on electronic transport properties, thereby maximizing the thermoelectric power generation. As it is essential to scrutinize comprehensively both electronic and thermal transport behaviors for nano-scale thermoelectric devices, we investigate the Seebeck coefficient, the electrical conductance, and the thermal conductivity of sinusoidally corrugated silicon nanowires and eventually look into an enhancement of the thermoelectric figure-of-merit [Formula: see text] from the modulated nanowires over typical straight nanowires. A loss in the electronic transport coefficient is calculated with the recursive Green function along with the Landauer formalism, and the thermal transport is simulated with the molecular dynamics. In contrast to a small influence on the thermopower and the electrical conductance of the geometry-modulated nanowires, a large reduction of the thermal conductivity yields an enhancement of the efficiency by 10% to 35% from the typical nanowires. We find that this approach can be easily extended to various structures and materials as we consider the geometrical modulation as a sole source of perturbation to the system. PMID:26650977

  17. Measuring Physician Quality and Efficiency in an Era of Practice Transformation: PCMH as a Case Study

    PubMed Central

    Sandy, Lewis G.; Haltson, Heidi; Metfessel, Brent A.; Reese, Conway

    2015-01-01

    Practicing physicians face myriad challenges as health care undergoes considerable transformation, including advancing efforts to measure and report on physician quality and efficiency, as well as the growth of new care models such as Accountable Care Organizations and patient-centered medical homes (PCMHs). How do these transformational forces relate to one another? How should practicing physicians focus and prioritize their improvement efforts? This Special Report examines how physicians’ performance on quality and efficiency measures may interact with delivery reforms, focusing on the PCMH. We note that although the PCMH is a promising model, published evidence is mixed. Using data and experience from a large commercial insurer’s performance transparency and PCMH programs, we further report that longitudinal analysis of UnitedHealthcare’s PCMH program experience has shown favorable changes; however, cross-sectional analysis indicates that National Committee for Quality Assurance’s PCMH designation is positively associated with achieving program Quality benchmarks, but negatively associated with program Efficiency benchmarks. This example illustrates some key issues for physicians in the current environment, and we provide suggestions for physicians and other stakeholders on understanding and acting on information from physician performance measurement programs. PMID:25964406

  18. Efficient Heterogeneous Execution on Large Multicore and Accelerator Platforms: Case Study Using a Block Tridiagonal Solver

    SciTech Connect

    Park, Alfred J; Perumalla, Kalyan S

    2013-01-01

    The algorithmic and implementation principles are explored in gainfully exploiting GPU accelerators in conjunction with multicore processors on high-end systems with large numbers of compute nodes, and evaluated in an implementation of a scalable block tridiagonal solver. The accelerator of each compute node is exploited in combination with multicore processors of that node in performing block-level linear algebra operations in the overall, distributed solver algorithm. Optimizations incorporated include: (1) an efficient memory mapping and synchronization interface to minimize data movement, (2) multi-process sharing of the accelerator within a node to obtain balanced load with multicore processors, and (3) an automatic memory management system to efficiently utilize accelerator memory when sub-matrices spill over the limits of device memory. Results are reported from our novel implementation that uses MAGMA and CUBLAS accelerator software systems simultaneously with ACML for multithreaded execution on processors. Overall, using 940 nVidia Tesla X2090 accelerators and 15,040 cores, the best heterogeneous execution delivers a 10.9-fold reduction in run time relative to an already efficient parallel multicore-only baseline implementation that is highly optimized with intra-node and inter-node concurrency and computation-communication overlap. Detailed quantitative results are presented to explain all critical runtime components contributing to hybrid performance.

  19. Efficiency of a solar cell with intermediate energy levels: An example study on hydrogen implanted Si solar cells

    NASA Astrophysics Data System (ADS)

    Ichimura, Masaya; Sakakibara, Hiromu; Wada, Koji; Kato, Masashi

    2013-09-01

    For any pn junction solar cell, there is a theoretical limit to its conversion efficiency, which is determined by its band gap. This efficiency may exceed the limit by introducing an intermediate level (IL) that can facilitate the sub-band-gap optical absorption, but the IL can simultaneously enhance the carrier recombination rate. To understand the net effects of the IL, it is necessary to estimate the rates of both the optical absorption and carrier capture via the IL. In this study, trap parameters and the optical absorption coefficient are evaluated for defect levels in hydrogen implanted silicon wafers using deep level transient spectroscopy, the optical-capacitance transient spectroscopy, and carrier lifetime measurements. Using the obtained trap parameters, the characteristics of hydrogen implanted silicon solar cells are simulated. The simulation results indicate that it is not possible to realize improvements in efficiency by performing hydrogen implantation.

  20. Study of convergence rate and efficiency of two-phase methods for approximating the Edgeworth-Pareto hull

    NASA Astrophysics Data System (ADS)

    Kamenev, G. K.

    2013-04-01

    The convergence rate and efficiency of two-phase methods for approximating the Edgeworth-Pareto hull in nonlinear multicriteria optimization problems is studied. A feature of two-phase methods is that the criteria images of randomly generated points of the decision space approach the Pareto frontier via local optimization of adaptively chosen convolutions of criteria. It is shown that the convergence rate of two-phase methods is determined by the metric properties of the set of local extrema of criteria convolutions, specifically, by its upper metric dimension. The efficiency of two-phase methods is examined; i.e., they are compared with hypothetical optimal methods of the same class. It is shown that the efficiency of two-phase methods is determined by the ratio of the ɛ-entropy and ɛ-capacity for the set of local extrema of criteria convolutions.

  1. The influence of bioaugmentation and biosurfactant addition on bioremediation efficiency of diesel-oil contaminated soil: feasibility during field studies.

    PubMed

    Szulc, Alicja; Ambrożewicz, Damian; Sydow, Mateusz; Ławniczak, Łukasz; Piotrowska-Cyplik, Agnieszka; Marecik, Roman; Chrzanowski, Łukasz

    2014-01-01

    The study focused on assessing the influence of bioaugmentation and addition of rhamnolipids on diesel oil biodegradation efficiency during field studies. Initial laboratory studies (measurement of emitted CO2 and dehydrogenase activity) were carried out in order to select the consortium for bioaugmentation as well as to evaluate the most appropriate concentration of rhamnolipids. The selected consortium consisted of following bacterial taxa: Aeromonas hydrophila, Alcaligenes xylosoxidans, Gordonia sp., Pseudomonas fluorescens, Pseudomonas putida, Rhodococcus equi, Stenotrophomonas maltophilia, Xanthomonas sp. It was established that the application of rhamnolipids at 150 mg/kg of soil was most appropriate in terms of dehydrogenase activity. Based on the obtained results, four treatment methods were designed and tested during 365 days of field studies: I) natural attenuation; II) addition of rhamnolipids; III) bioaugmentation; IV) bioaugmentation and addition of rhamnolipids. It was observed that bioaugmentation contributed to the highest diesel oil biodegradation efficiency, whereas the addition of rhamnolipids did not notably influence the treatment process. PMID:24291585

  2. Financial Impact of Energy Efficiency under a Federal Renewable Electricity Standard: Case Study of a Kansas"super-utility"

    SciTech Connect

    Goldman, Charles A.; Cappers, Peter

    2009-12-01

    Local, state and federal policies that jointly promote the generation of electricity from renewable technologies and the pursuit of energy efficiency are expected to help mitigate the detrimental effects of global climate change and foster energy independence. We examine the financial impacts on various stakeholders from alternative compliance strategies with a Combined Efficiency and Renewable Electricity Standard (CERES) using a case study approach for utilities in Kansas. If only supply-side options are considered, our analysis suggests that a Kansas"super-utility" would prefer to build its own renewable energy resources, while ratepayers would favor a procurement strategy that relies on long-term renewable power purchase agreements. Introducing energy efficiency under varying levels as a CERES resource will, under our analysis, reduce ratepayer bills by ~;;$400M to ~;;$1.0B between 2009 and 2028, but commensurately erode shareholder returns by ~;;10 to ~;;100 basis points. If a business model for energy efficiency inclusive of both a lost fixed cost recovery mechanism and a shareholder incentive mechanism is implemented, our results illustrate how shareholder returns can be improved through the pursuit of energy efficiency, by at most ~;;20 basis points if certain conditions apply, while ratepayers continue to save between $10M and ~;;$840M over 20 years.

  3. A Monte Carlo study of lung counting efficiency for female workers of different breast sizes using deformable phantoms

    PubMed Central

    Hegenbart, L; Na, Y H; Zhang, J Y; Urban, M; Xu, X George

    2009-01-01

    There are currently no physical phantoms available for calibrating in vivo counting devices that represent women with different breast sizes because such phantoms are difficult, time consuming and expensive to fabricate. In this work, a feasible alternative involving computational phantoms was explored. A series of new female voxel phantoms with different breast sizes were developed and ported into a Monte Carlo radiation transport code for performing virtual lung counting efficiency calibrations. The phantoms are based on the RPI adult female phantom, a boundary representation (BREP) model. They were created with novel deformation techniques and then voxelized for the Monte Carlo simulations. Eight models have been selected with cup sizes ranging from AA to G according to brassiere industry standards. Monte Carlo simulations of a lung counting system were performed with these phantoms to study the effect of breast size on lung counting efficiencies, which are needed to determine the activity of a radionuclide deposited in the lung and hence to estimate the resulting dose to the worker. Contamination scenarios involving three different radionuclides, namely Am-241, Cs-137 and Co-60, were considered. The results show that detector efficiencies considerably decrease with increasing breast size, especially for low energy photon emitting radionuclides. When the counting efficiencies of models with cup size AA were compared to those with cup size G, a difference of up to 50% was observed. The detector efficiencies for each radionuclide can be approximated by curve fitting in the total breast mass (polynomial of second order) or the cup size (power). PMID:18780959

  4. The effects of solution chemistry on the sticking efficiencies of viable Enterococcus faecalis: An atomic force microscopy and modeling study

    NASA Astrophysics Data System (ADS)

    Cail, Tracy L.; Hochella, Michael F.

    2005-06-01

    Atomic force microscopy (AFM) and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in combination with the interaction force boundary layer (IFBL) model have been used to empirically and theoretically calculate sticking efficiencies (α) of Enterococcus faecalis cells against a silica glass surface. Sticking efficiencies were calculated in solutions of varying pH and ionic strength and related to maximum distances of transport through a hypothetical soil block using colloid filtration theory. AFM measurements show that the repulsive and attractive forces between E. faecalis cells and a glass surface are a function of ionic strength but are less sensitive to changes in solution pH. Zeta (ζ)-potential measurements of the cells and glass surfaces correlate with these trends. Calculated DLVO energy profiles predict much greater sensitivity to changing solution chemistry. Sticking efficiencies derived from AFM measurements range from 9.6 × 10 -17 to 1 in solutions of low ionic strength (IS) and from 2.6 × 10 -33 to 1 at higher IS. Corresponding α values determined from DLVO theory are essentially zero in all tested solutions. Sticking efficiencies calculated in this study are smaller than values determined from column and field studies in similar systems; however, α derived from AFM data and the IFBL model more closely represent field data than do values calculated from DLVO energy values. A comparison with different methods of calculating α suggests that reversible adhesion may be significant in column-scale transport studies.

  5. Efficient Use of Terrestrial Economic Services: A Case Study in South Korea

    NASA Astrophysics Data System (ADS)

    Nguyen, T. T.; Tenhunen, J.; Hoang, V. N.; Koellner, T.; Shin, H.; Pham, V. D.; Seo, B.

    2012-04-01

    Understanding the linkages between social and ecological systems is crucial for managing potential responses to global change. Agricultural production requires resources, is determined by ecological processes, and results in economic goods and services for society. However, production leads at the same time to both positive and negative externalities. The externalities can be enhanced or mitigated by human behavior in management, which is mainly driven by expectations related to economic gains and losses. Ecological and economic processes are interrelated, and continuously interact in a complex manner. Therefore, understanding potential economic gains and losses in response to global change is a fundamental consideration in order to carry out well-informed decision-making. The International Research and Training Group TERRECO at the University of Bayreuth has intensively investigated ecological systems and processes in forested and agricultural landscapes as well as at regional scale in South Korea. These ongoing efforts provide a unique opportunity to examine the economic gains, losses and trade-offs that may occur with future climate and land-use change. Within this framework, we first investigated the environmental and economic efficiency of rice farms in Kangwon Province of South Korea, since rice is the most important food crop in this country. We then expanded our analysis to include dry farm highland vegetable crops in an intensively farmed region of the country, Haean Catchment. Our main objectives are (1) to categorize different types of farms, (2) determine their economic and environmental efficiency, and (3) to determine the trade-offs that occur in economic and environmental efficiencies under alternative management schemes and alternative climate regimes. Our preliminary analysis for rice farms yielded several important findings. First, both the production cost and environmental pollution by rice farms could be reduced significantly. Improvements in

  6. National Energy Efficiency Evaluation, Measurement and Verification (EM&V) Standard: Scoping Study of Issues and Implementation Requirements

    SciTech Connect

    Schiller Consulting, Inc.; Schiller, Steven R.; Goldman, Charles A.; Galawish, Elsia

    2011-02-04

    This report is a scoping study that identifies issues associated with developing a national evaluation, measurement and verification (EM&V) standard for end-use, non-transportation, energy efficiency activities. The objectives of this study are to identify the scope of such a standard and define EM&V requirements and issues that will need to be addressed in a standard. To explore these issues, we provide and discuss: (1) a set of definitions applicable to an EM&V standard; (2) a literature review of existing guidelines, standards, and 'initiatives' relating to EM&V standards as well as a review of 'bottom-up' versus 'top-down' evaluation approaches; (3) a summary of EM&V related provisions of two recent federal legislative proposals (Congressman Waxman's and Markey's American Clean Energy and Security Act of 2009 and Senator Bingaman's American Clean Energy Leadership Act of 2009) that include national efficiency resource requirements; (4) an annotated list of issues that that are likely to be central to, and need to be considered when, developing a national EM&V standard; and (5) a discussion of the implications of such issues. There are three primary reasons for developing a national efficiency EM&V standard. First, some policy makers, regulators and practitioners believe that a national standard would streamline EM&V implementation, reduce costs and complexity, and improve comparability of results across jurisdictions; although there are benefits associated with each jurisdiction setting its own EM&V requirements based on their specific portfolio and evaluation budgets and objectives. Secondly, if energy efficiency is determined by the US Environmental Protection Agency to be a Best Available Control Technology (BACT) for avoiding criteria pollutant and/or greenhouse gas emissions, then a standard can be required for documenting the emission reductions resulting from efficiency actions. The third reason for a national EM&V standard is that such a standard is

  7. Efficiency Goals

    ERIC Educational Resources Information Center

    Graham, Donald

    2009-01-01

    The lighting of learning environments is an important focus in designing new schools and renovating older schools. Studies long have shown that appropriate lighting levels and daylighting improve learning; now, climbing energy budgets have spurred school administrators to seek more efficient use of lighting. Electricity rates are expected to rise…

  8. Construction of low current 30 keV proton accelerator for detection efficiency studies

    NASA Astrophysics Data System (ADS)

    Salas Bacci, Americo; Baessler, Stefan; Ross, Aaron; Roane, Nicholas; Whitaker, C. J.

    2013-10-01

    We have constructed a small ion source and proton accelerator at UVA. This accelerator is needed for the characterization of the detection efficiency of a large area, thick, 127-hexagonal segmented Silicon detector for the neutron beta decay ``Nab'' experiment that will be carried out at SNS, Oak Ridge National Laboratory in search of physics beyond the standard model. We will present the design, simulations, operation, and detection of 30 keV H+ and H2+, as well as our efforts to stabilize and correlate both ion currents.

  9. Photodissociation Efficiency Spectroscopy Study of the Rydberg Excited Ion-Pair States of Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Feng, Qiang; Xu, Yun-Feng; Sun, Jin-Da; Tian, Shan-Xi; Shan, Xiao-Bin; Liu, Fu-Yi; Sheng, Liu-Si

    2009-10-01

    Photodissociation efficiency spectrum of anionic oxygen atom produced via ion-pair dissociations of carbon dioxide is recorded by means of the synchrotron radiation excitation (XUV photon energy 17.40-20.00 eV). The present spectrum is assigned as the Rydberg-like excited ion-pair states, i.e., Tanaka-Ogawa and Henning series, tilde C2Σg+ (CO+2) vibrational ground-state and excitation series. Three Rydberg series, npσu, npπu, and nfu, converging to tilde C2Σg+ (0, 0, 0), show the higher cross sections.

  10. Impact of storm water runoff on efficiency of the effluent treatment plant - a case study

    SciTech Connect

    Suresh, I.V.; Murthy, M.V.R.L.; Sanghi, S.K.; Yadava, R.N.; Wanganeo, A.

    1996-04-01

    This paper evaluates the impact of storm water runoff on an existing sewage treatment plant situated in an industrial township. Significant dilution effect is observed during the monsoon period (June-September) in the influent and effluent characteristics of sewage. The estimated excess runoff water during these months is mainly due to the rainfall in the region and due to the absence of proper control or design for the collection of storm water, thereby avoiding the discharge of the storm water into the treatment plant. This has resulted in the reduction of BOD, COD, total nitrogen and total phosphorus, thus decreasing the efficiency of gas generation. 7 refs., 5 figs., 5 tabs.

  11. Optimal thickness of silicon membranes to achieve maximum thermoelectric efficiency: A first principles study

    NASA Astrophysics Data System (ADS)

    Mangold, Claudia; Neogi, Sanghamitra; Donadio, Davide

    2016-08-01

    Silicon nanostructures with reduced dimensionality, such as nanowires, membranes, and thin films, are promising thermoelectric materials, as they exhibit considerably reduced thermal conductivity. Here, we utilize density functional theory and Boltzmann transport equation to compute the electronic properties of ultra-thin crystalline silicon membranes with thickness between 1 and 12 nm. We predict that an optimal thickness of ˜7 nm maximizes the thermoelectric figure of merit of membranes with native oxide surface layers. Further thinning of the membranes, although attainable in experiments, reduces the electrical conductivity and worsens the thermoelectric efficiency.

  12. Joint implementation initiatives in South Africa: A case study of two energy-efficiency projects

    SciTech Connect

    Van Horen, C.; Simmonds, G.; Parker, G.

    1998-11-01

    This paper explores the issues pertinent to Joint Implementation (JI) in South Africa by examining two prototype potential projects on energy efficiency with the potential for reducing greenhouse gas (GHG) emissions. The first is an energy-efficient lighting project based on the public electricity utility, Eskom's plan for a compact fluorescent lighting program in the residential sector. The analysis indicates that the CFL program could avoid emissions of up to 243 thousand tons of carbon over the first five years, at negative cost (that is, with a positive economic return). The second project involves the delivery of passive solar, energy-efficient housing to a low-income township in the Western Cape Province, at an incremental capital cost of approximately $2.5m for the 6000 houses. In this case, the avoided GHG emissions over the first five years amount to between 14 and 20 tons of carbon, and over the 50 year life-span of the project it will result to 140 to 200 thousand tons of avoided emissions at a cost of $13 to $17 per ton. The housing project has significant non-GHG benefits such as savings on energy bills and health, which accrue to the low-income dwellers. A number of important JI-specific issues and concerns emerge with respect to the two projects, which can also be applied to other potential JI opportunities in the country generally. These include the issues of carbon credit sharing, for which a number of scenarios are suggested, as well as estimating unknown macroeconomic impacts, such as the effects of CFLs on the country's incandescent lighting industry. Findings from an examination of both potential projects conclude that capacity-building within the country is critical to ensure that the technology being transferred balances efficiency, cost and quality appropriate to the South African context. Finally, assessment and evaluation, monitoring and verification criteria and institutions are called for to guarantee measurable long-term environmental

  13. Relationship between efficiency and clinical effectiveness indicators in an adjusted model of resource consumption: a cross-sectional study

    PubMed Central

    2013-01-01

    Background Adjusted clinical groups (ACG®) have been widely used to adjust resource distribution; however, the relationship with effectiveness has been questioned. The purpose of the study was to measure the relationship between efficiency assessed by ACG® and a clinical effectiveness indicator in adults attended in Primary Health Care Centres (PHCs). Methods Research design: cross-sectional study. Subjects: 196, 593 patients aged >14 years in 13 PHCs in Catalonia (Spain). Measures: Age, sex, PHC, basic care team (BCT), visits, episodes (diagnoses), and total direct costs of PHC care and co-morbidity as measured by ACG® indicators: Efficiency indices for costs, visits, and episodes (costs EI, visits EI, episodes EI); a complexity or risk index (RI); and effectiveness measured by a general synthetic index (SI). The relationship between EI, RI, and SI in each PHC and BCT was measured by multiple correlation coefficients (r). Results In total, 56 of the 106 defined ACG® were present in the study population, with five corresponding to 44.5% of the patients, 11 to 68.0% of patients, and 30 present in less than 0.5% of the sample. The RI in each PHC ranged from 0.9 to 1.1. Costs, visits, and episodes had similar trends for efficiency in six PHCs. There was moderate correlation between costs EI and visits EI (r = 0.59). SI correlation with episodes EI and costs EI was moderate (r = 0.48 and r = −0.34, respectively) and was r = −0.14 for visits EI. Correlation between RI and SI was r = 0.29. Conclusions The Efficiency and Effectiveness ACG® indicators permit a comparison of primary care processes between PHCs. Acceptable correlation exists between effectiveness and indicators of efficiency in episodes and costs. PMID:24139144

  14. Can diversity in root architecture explain plant water use efficiency? A modeling study

    PubMed Central

    Tron, Stefania; Bodner, Gernot; Laio, Francesco; Ridolfi, Luca; Leitner, Daniel

    2015-01-01

    Drought stress is a dominant constraint to crop production. Breeding crops with adapted root systems for effective uptake of water represents a novel strategy to increase crop drought resistance. Due to complex interaction between root traits and high diversity of hydrological conditions, modeling provides important information for trait based selection. In this work we use a root architecture model combined with a soil-hydrological model to analyze whether there is a root system ideotype of general adaptation to drought or water uptake efficiency of root systems is a function of specific hydrological conditions. This was done by modeling transpiration of 48 root architectures in 16 drought scenarios with distinct soil textures, rainfall distributions, and initial soil moisture availability. We find that the efficiency in water uptake of root architecture is strictly dependent on the hydrological scenario. Even dense and deep root systems are not superior in water uptake under all hydrological scenarios. Our results demonstrate that mere architectural description is insufficient to find root systems of optimum functionality. We find that in environments with sufficient rainfall before the growing season, root depth represents the key trait for the exploration of stored water, especially in fine soils. Root density, instead, especially near the soil surface, becomes the most relevant trait for exploiting soil moisture when plant water supply is mainly provided by rainfall events during the root system development. We therefore concluded that trait based root breeding has to consider root systems with specific adaptation to the hydrology of the target environment. PMID:26412932

  15. Power-efficiency trade-off in low-dimensional thermoelectrics- An RTD study

    NASA Astrophysics Data System (ADS)

    Agarwal, Akshay; Muralidharan, Bhaskaran

    2014-03-01

    A distortion in the quantum mechanical transmission due to confinement in a low-dimensional thermoelectric often points to a better figure of merit (zT). While an enhancement in zT is a highly desirable feature for a good thermoelectric, it does not provide a complete picture of the thermoelectric operation. One such aspect not apparent with a zT-based anaylsis is the trade-off between the power generated and the efficiency resulting from such a distortion. Another aspect is the role of Coulomb charging resulting from the confinement. In this talk, we elucidate the role of charging as well as the distortion in the transmission function on the thermoelectric performance using a double barrier resonant tunneling diode (RTD) set up. Transport simulations are performed using the non-equilibrium Green's function (NEGF) formalism coupled self-consistently with the Poisson equation. Various levels of transmission distortion and charging scenarios are achieved by tailoring the physical parameter space of the RTD device. The resulting set of physical situations in the simulated RTD device will provide a detailed insight into the power-efficiency trade-off trend that should result from a generic quantum confinement scenario.

  16. A high-efficiency system for the generation and study of human induced pluripotent stem cells.

    PubMed

    Maherali, Nimet; Ahfeldt, Tim; Rigamonti, Alessandra; Utikal, Jochen; Cowan, Chad; Hochedlinger, Konrad

    2008-09-11

    Direct reprogramming of human fibroblasts to a pluripotent state has been achieved through ectopic expression of the transcription factors OCT4, SOX2, and either cMYC and KLF4 or NANOG and LIN28. Little is known, however, about the mechanisms by which reprogramming occurs, which is in part limited by the low efficiency of conversion. To this end, we sought to create a doxycycline-inducible lentiviral system to convert primary human fibroblasts and keratinocytes into human induced pluripotent stem cells (hiPSCs). hiPSCs generated with this system were molecularly and functionally similar to human embryonic stem cells (hESCs), demonstrated by gene expression profiles, DNA methylation status, and differentiation potential. While expression of the viral transgenes was required for several weeks in fibroblasts, we found that 10 days was sufficient for the reprogramming of keratinocytes. Using our inducible system, we developed a strategy to induce hiPSC formation at high frequency. Upon addition of doxycycline to hiPSC-derived differentiated cells, we obtained "secondary" hiPSCs at a frequency at least 100-fold greater than the initial conversion. The ability to reprogram cells at high efficiency provides a unique platform to dissect the underlying molecular and biochemical processes that accompany nuclear reprogramming. PMID:18786420

  17. Efficiency of an emissions payment system for nitrogen in sewage treatment plants - a case study.

    PubMed

    Malmaeus, J Mikael; Ek, Mats; Åmand, Linda; Roth, Susanna; Baresel, Christian; Olshammar, Mikael

    2015-05-01

    An emissions payment system for nitrogen in Swedish sewage treatment plants (STPs) was evaluated using a semi-empirical approach. The system was based on a tariff levied on each unit of nitrogen emitted by STPs, and profitable measures to reduce nitrogen emissions were identified for twenty municipal STPs. This was done through direct involvement with the plant personnel and the results were scaled up to cover all treatment plants larger than 2000 person equivalents in the Swedish tributary areas of the Kattegat and the Baltic Proper. The sum of costs and nitrogen reductions were compared with an assumed command-and-control regulation requiring all STPs to obtain 80% total nitrogen reduction in their effluents. Costs for the latter case were estimated using a database containing standard estimates for reduction costs by six specified measures. For both cases a total reduction target of 3000 tonnes of nitrogen was set. We did not find that the emissions payment system was more efficient in terms of total reduction costs, although some practical and administrative advantages could be identified. Our results emphasize the need to evaluate the performance of policy instruments on a case-by-case basis since the theoretical efficiency is not always reflected in practice. PMID:25753396

  18. A Study on Energy Efficient MAC Protocol of Wireless Sensor Network for Ubiquitous Agriculture

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Chul; Lee, Ji-Woong; Hwang, Jeong-Hwan; Yoe, Hyun

    Various technologies are used in the agricultural sites now. Especially, the recent application of sensor network related technology is quite notable. Considering the efficiency of MAC protocol of WSN is being researched in various aspects, it is believed that a research on how to apply the MAC protocol to agriculture would be also required. This research is based on the sensor node developed by Sunchon University ITRC. Once the sensor nodes are effectively located in the farm, they operate for a long time and they are rarely relocated once installed. The concentration of multiple sensor nodes in a narrow area is another characteristic the sensor node. The purpose of this research is to select a sensor network MAC protocol, which would be most proper to agricultural site with good energy efficiency and excellent transmission delay performance. The applicable protocols such as S-MAC and X-MAC were set up for the installation environment. They were compared and a methodology to select the most optimum protocol to agricultural site is suggested.

  19. Study of lower hybrid current drive efficiency and its correlation with photon temperatures in the HT-7 tokamak

    NASA Astrophysics Data System (ADS)

    Younis, J.; Wan, B. N.; Lin, S. Y.; Shi, Y. J.; Ding, B. J.; Gong, X.; HT-7 Team

    2009-07-01

    Lower hybrid current drive (LHCD) efficiency is a very important parameter. The experimental current drive efficiency is defined as η = IrfneR/PLH, where Irf is the current driven by the lower hybrid waves (LHWs), ne is the central line-average density, R is the major radius of the plasma and PLH is the injected LH wave power absorbed by the plasma through Landau damping. A study of current drive efficiency of LHWs in the HT-7 tokamak has been carried out in the parameter ranges: ne = (1.2-2.5) × 1019 m-3, Ip = (80-200) kA, Bt = 1.8 T, PLH = (188-532) kW in the limiter configuration. Current drive efficiency is investigated through a simple correlation with photon temperature and normalized intensity of fast electron bremstrahlung emission, which is, in the first approximation, proportional to the averaged velocity and population of the fast electrons. The plasma current scanning experiment shows that CD efficiency increase is due to the increase in both the photon temperature and the population of the fast electrons generated by LHWs. The density scanning experiment shows that as the plasma density is increased, an increment in CD efficiency along with the increase in the population of fast electrons is observed. The slowing down through the collisions with bulk electrons is mainly responsible for the decreased photon temperature during the plasma density scan. These experiments strongly suggest the dominant role of the population of fast electrons generated by LHCD and the generation of the current carried by fast electrons.

  20. Comparative Study of Three Commonly Used Methods for Hospital Efficiency Analysis in Beijing Tertiary Public Hospitals, China

    PubMed Central

    Xu, Guo-Chao; Zheng, Jian; Zhou, Zi-Jun; Zhou, Chuan-Kun; Zhao, Yang

    2015-01-01

    Background: Tertiary hospitals serve as the medical service center within the region and play an important role in the medical and health service system. They are also the key targets of public hospital reform in the new era in China. Through the reform of health system, the public hospital efficiency has changed remarkably. Therefore, this study aimed to provide some advice for efficiency assessment of public hospitals in China by comparing and analyzing the consistency of results obtained by three commonly used methods for examining hospital efficiency, that is, ratio analysis (RA), stochastic frontier analysis (SFA), and data envelopment analysis (DEA). Methods: The theoretical basis, operational processes, and the application status of RA, SFA, and DEA were learned through literature analysis. Then, the empirical analysis was conducted based on measured data from 51 tertiary public hospitals in Beijing from 2009 to 2011. Results: The average values of hospital efficiency calculated by SFA with index screening and principal component analysis (PCA) results and those calculated by DEA with index screening results were relatively stable. The efficiency of specialized hospitals was higher than that of general hospitals and that of traditional Chinese medicine hospitals. The results obtained by SFA with index screening results and the results obtained by SFA with PCA results showed a relatively high correlation (r-value in 2009, 2010, and 2011 were 0.869, 0.753, and 0.842, respectively, P < 0.01). The correlation between results obtained by DEA with index screening results and PCA results and results obtained by other methods showed statistical significance, but the correlation between results obtained by DEA with index screening results and PCA results was lower than that between results obtained by SFA with index screening results and PCA results. Conclusions: RA is not suitable for multi-index evaluation of hospital efficiency. In the given conditions, SFA is a

  1. MARKING INSECTS FOR STUDYING ECOLOGY AND ETHOLOGY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different kinds of markers can be used for studying insect ecology and behavior, and each have special strengths, weaknesses, and applications. Various kinds of markers are described, including visual tags (e.g., paint, wires, dyes, pollen, and spores), rubidium, radiotracers, rare earth elements, ...

  2. Study on High Efficient Absorption Refrigerator Using Multi-effect Cycle

    NASA Astrophysics Data System (ADS)

    Inoue, Naoyuki; Irie, Tomoyoshi; Saito, Kiyoshi; Kawai, Sunao

    Double effect chillers are commonly used as cooling machines for air condition. Great efforts have been making to improve the efficiency for a long time, and now the COP is very near to the limitation of double effect cycles. Triple effect cycles are expected for the next step beyond double effect cycles, but have some problems of high temperature and high pressure in the high stage generator. High temperature of absorbent causes corrosion problem and high vapor pressure over atmospheric pressure causes the restriction of legal regulation. This paper deals with many types of triple effect cycles. The temperature and dew point of the high stage generator are analyzed, several types are selected for low dew point, and one of them is more analyzed in detail.

  3. Study on the Efficient Drive of a Desiccant Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Jeong, Jong-Soo; Saito, Kiyoshi; Kawai, Sunao

    This paper constructs the static simulation model of a desiccant air conditioning system and gives the guidelines for the efficient drive of the desiccant air conditioning system. The desiccant air conditioning system is composed of a desiccant wheel, a heat exchanger, two evaporative coolers and a heater. The process air and regeneration air are supplied to this system. The desiccant is Silica gel. In the simulation model, two-dimensional model in space is adopted for the desiccant wheel. As the simulation result, it is clarified that optimum outlet temperature of the regeneration air in the heater, rotational speed of the desiccant wheel, the rejected air flow rate of the regeneration air, the process and regeneration air flow rate that maximize COP exist. For example, in case that the regeneration temperature is 63°C and relative humidity is 55% maximum COP is about 0.62.

  4. An efficient computational method for use in structural studies of crystals with substitutional disorder.

    PubMed

    Poloni, Roberta; Íñiguez, Jorge; García, Alberto; Canadell, Enric

    2010-10-20

    We present a computationally efficient semi-empirical method, based on standard first-principles techniques and the so-called virtual crystal approximation, for determining the average atomic structure of crystals with substitutional disorder. We show that, making use of a minimal amount of experimental information, it is possible to define convenient figures of merit that allow us to recast the determination of the average atomic ordering within the unit cell as a minimization problem. We have tested our approach by applying it to a wide variety of materials, ranging from oxynitrides to borocarbides and transition-metal perovskite oxides. In all the cases we were able to reproduce the experimental solution, when it exists, or the first-principles result obtained by means of much more computationally intensive approaches. PMID:21386597

  5. [Study of clinical efficiency of essential phospholipids and silymarin combination in nonalcoholic and alcoholic steatohepatitis].

    PubMed

    Iakimchuk, G N; Gendrikson, L N

    2011-01-01

    The issues of steatohepatitis treatment in the pathogenesis of which a major role plays lipid accumulation in hepatocyte and increased processes of free radical oxidation of lipids. Developed a method of treatment of patients with alcoholic and nonalcoholic steatohepatitis with the inclusion of a combination of essential phospholipids (EPL) and silymarin (SM). A comparative assessment of results of treatment with the inclusion of a combination of EPL and SM, Essentiale and Carsil in 60 patients with alcoholic and nonalcoholic steatohepatitis. Revealed the preferential efficiency of combination EPL and SM in these patients in regard of shortening the time clinical manifestations of disease, reducing transaminase activity, normalization of the cholestasis and cholesterol. Given practical recommendations of treatment patients with alcoholic and nonalcoholic steatohepatitis with the inclusion of a combination of EPL and CM. PMID:22364002

  6. Efficient utilization of launched threads on GPUs: The spherical harmonic transform as a case study

    NASA Astrophysics Data System (ADS)

    Lu, Feng-shun; Song, Jun-qiang; Lin, Wang-qun; Pang, Yu-fei; Ren, Kai-jun; Shi, Pei-chang

    2013-11-01

    Maximum utilization of hardware resources is crucial to leverage the enormous computational power of graphics processing units (GPUs). However, there lacks an effective metric to denote whether the launched threads are kept busy. To address this issue, we propose a metric called ETU to describe the efficiency of threads utilization. First, we execute several CUDA-SDK sample codes, with(out) double precision arithmetic, on two generations of GPUs so as to perform a preliminary validation of the ETU metric. Taking the spherical harmonic transform as an example, we then give two GPU implementations for Legendre transforms and check the relationship between ETU and application performance. Experimental results show that applications with larger ETU can usually achieve better performance, which is more accurate than occupancy proposed by NVIDIA. Finally, we select the GPU implementations with better performance to accelerate Legendre transforms in STSWM, which is a spectral transform shallow water model.

  7. Report of feasibility study on international-cooperation in high efficient energy conversion technology

    NASA Astrophysics Data System (ADS)

    1993-03-01

    With regard to accelerated introduction of high efficient energy conversion technology to developing countries, the paper investigates the countries' thoughts of the introduction of the technology and the status of the introduction bases. The countries for survey are the Philippines, Indonesia, Malaysia and Thailand. The Philippine government expects to develop cogeneration as well as large power sources and to widen effective use of natural energy. In Indonesia, they largely expect effective use of biomass energy using Stirling engines by international cooperation and the promoted local electrification using standalone distributed fuel cells. In Malaysia, they have great expectations of the introduction of air conditioning facilities using Stirling engines and the use of standalone distributed fuel cells for promotion of local electrification. Thailand hopes for the use of Stirling engines to air conditioning systems, and the development of solar Stirling generators with solar energy as a heat source and electric vehicles.

  8. An experimental study of energy loss mechanisms and efficiency consideration in the low power dc arcjet

    NASA Technical Reports Server (NTRS)

    Curran, F. M.

    1985-01-01

    The potential utility of the low power dc arcjet in auxiliary propulsion was investigated. It was indicated that improvements in the areas of stability, energy efficiency, reliability, and electrode erosion are necessary to obtain a useful device. A water-cooled arcjet simulator was tested to investigate both the energy loss mechanisms at the electrodes and the stability of different conventional arcjet configurations in the presence of a vortex flow field. It is shown that in certain configurations only 25 to 30% of the input energy is lost to the electrodes. It is also shown that vortex stabilization is not difficult to obtain in many cases at the flow rates used and that a careful starting procedure is effective in minimizing electrode damage.

  9. An experimental study of energy loss mechanisms and efficiency considerations in the low power dc arcjet

    NASA Technical Reports Server (NTRS)

    Curran, F. M.

    1985-01-01

    The potential utility of the low power dc arcjet in auxiliary propulsion was investigated. It was indicated that improvements in the areas of stability, energy efficiency, reliability, and electrode erosion are necessary to obtain a useful device. A water-cooled arcjet simulator was tested to investigate both the energy loss mechanisms at the electrodes and the stability of different conventional arcjet configurations in the presence of a vortex flow field. It is shown that in certain configurations only 25 to 30 percent of the input energy is lost to the electrodes. It is also shown that vortex stabilization is not difficult to obtain in many cases at the flow rates used and that a careful starting procedure is effective in minimizing electrode damage.

  10. A computational study of the effect of unstructured mesh quality on solution efficiency

    SciTech Connect

    Batdorf, M.; Freitag, L.A.; Ollivier-Gooch, C.

    1997-09-01

    It is well known that mesh quality affects both efficiency and accuracy of CFD solutions. Meshes with distorted elements make solutions both more difficult to compute and less accurate. We review a recently proposed technique for improving mesh quality as measured by element angle (dihedral angle in three dimensions) using a combination of optimization-based smoothing techniques and local reconnection schemes. Typical results that quantify mesh improvement for a number of application meshes are presented. We then examine effects of mesh quality as measured by the maximum angle in the mesh on the convergence rates of two commonly used CFD solution techniques. Numerical experiments are performed that quantify the cost and benefit of using mesh optimization schemes for incompressible flow over a cylinder and weakly compressible flow over a cylinder.

  11. Efficient screening for COPD using three steps: a cross-sectional study in Mexico City

    PubMed Central

    Franco-Marina, Francisco; Fernandez-Plata, Rosario; Torre-Bouscoulet, Luis; García-Sancho, Cecilia; Sanchez-Gallen, Elisa; Martinez, David; Perez-Padilla, Rogelio

    2014-01-01

    Background: Underdiagnosis of chronic obstructive pulmonary disease (COPD) in primary care can be improved by a more efficient screening strategy. Aims: To evaluate a three-step method of screening for COPD consisting of an initial short questionnaire followed by measurement of forced expiratory volume in 1s/forced expiratory volume in 6s (FEV1/FEV6) using an inexpensive pocket spirometer in those with high risk, and diagnostic quality spirometry in those with a low FEV1/FEV6. Methods: We analysed two related Mexico City cross-sectional samples. The 2003 Mexico City PLATINO survey (n=542) was used to develop a short questionnaire to determine the risk of COPD and a 2010 survey (n=737) additionally used a pocket spirometer. The discriminatory power of the two instruments was assessed with receiver operator characteristic (ROC) curves using three COPD definitions. Results: The developed COPD scale included two variables from a simple questionnaire and, in ROC analysis, an area under the curve (AUC) between 0.64 and 0.77 was found to detect COPD. The pocket spirometer had an AUC between 0.85 and 0.88 to detect COPD. Using the COPD scale as a first screening step excluded 35–48% of the total population from further testing at the cost of not detecting 8–18% of those with COPD. Using the pocket spirometer and sending those with a FEV1/FEV6<0.80 for diagnostic quality spirometry is very efficient, and substantially improved the positive predictive value at the cost of not detecting one-third of COPD cases. Conclusions: A three-step screening strategy for COPD substantially reduces the need for spirometry testing when only a COPD scale is used for screening. PMID:24841708

  12. Experimental study on the disinfection efficiencies of a continuous-flow ultrasound/ultraviolet baffled reactor.

    PubMed

    Zhou, Xiaoqin; Guo, Hao; Li, Zifu; Zhao, Junyuan; Yun, Yupan

    2015-11-01

    A self-designed continuous-flow ultrasound/ultraviolet (US/UV) baffled reactor was tested in this work, and the disinfection efficiency of secondary effluent from a wastewater treatment plant (WWTP) was investigated in terms of the different locations of ultrasonic transducers inside the reactor under similar input power densities and specific energy consumptions. Results demonstrated that the two-stage simultaneous US/UV irradiation in both chambers 2 and 3 at a flow rate of 1200 L/h performed excellent disinfection efficiency. It achieved an average feacal coliforms concentration of 201±78 colony forming unit (CFU)/L in the effluent and an average of (4.24±0.26) log10 reduction. Thereafter, 8 days of continuous operation was performed under such a condition. A total of 31 samples were taken, and all the samples were analyzed in triplicate for feacal coliforms analysis. Experimental results showed that feacal coliforms concentrations remained at about 347±174 CFU/L under the selected optimum disinfection condition, even if the influent concentrations fluctuated from 3.97×10(5) to 3.57×10(6) CFU/L. This finding implied that all effluents of continuous-flow-baffled-reactor with simultaneous US/UV disinfection could meet the requirements of the discharge standard of pollutants for municipal WWTP (GB 18918-2002) Class 1-A (1000 CFU/L) with a specific energy consumption of 0.219 kWh/m(3). Therefore, the US/UV disinfection process has great potential for practical applications. PMID:26186823

  13. Case study on incentive mechanism of energy efficiency retrofit in coal-fueled power plant in China.

    PubMed

    Yuan, Donghai; Guo, Xujing; Cao, Yuan; He, Liansheng; Wang, Jinggang; Xi, Beidou; Li, Junqi; Ma, Wenlin; Zhang, Mingshun

    2012-01-01

    An ordinary steam turbine retrofit project is selected as a case study; through the retrofit, the project activities will generate emission reductions within the power grid for about 92,463 tCO(2)e per annum. The internal rate of return (IRR) of the project is only -0.41% without the revenue of carbon credits, for example, CERs, which is much lower than the benchmark value of 8%. Only when the unit price of carbon credit reaches 125 CNY/tCO(2), the IRR could reach the benchmark and an effective carbon tax needs to increase the price of carbon to 243 CNY/tce in order to make the project financially feasible. Design of incentive mechanism will help these low efficiency enterprises improve efficiency and reduce CO(2) emissions, which can provide the power plants sufficient incentive to implement energy efficiency retrofit project in existing coal-fuel power generation-units, and we hope it will make a good demonstration for the other low efficiency coal-fueled power generation units in China. PMID:23365532

  14. Case Study on Incentive Mechanism of Energy Efficiency Retrofit in Coal-Fueled Power Plant in China

    PubMed Central

    Yuan, Donghai; Guo, Xujing; Cao, Yuan; He, Liansheng; Wang, Jinggang; Xi, Beidou; Li, Junqi; Ma, Wenlin; Zhang, Mingshun

    2012-01-01

    An ordinary steam turbine retrofit project is selected as a case study; through the retrofit, the project activities will generate emission reductions within the power grid for about 92,463 tCO2e per annum. The internal rate of return (IRR) of the project is only −0.41% without the revenue of carbon credits, for example, CERs, which is much lower than the benchmark value of 8%. Only when the unit price of carbon credit reaches 125 CNY/tCO2, the IRR could reach the benchmark and an effective carbon tax needs to increase the price of carbon to 243 CNY/tce in order to make the project financially feasible. Design of incentive mechanism will help these low efficiency enterprises improve efficiency and reduce CO2 emissions, which can provide the power plants sufficient incentive to implement energy efficiency retrofit project in existing coal-fuel power generation-units, and we hope it will make a good demonstration for the other low efficiency coal-fueled power generation units in China. PMID:23365532

  15. Evaluation of the Efficiency of the Atraumatic Endotracheal Tube in the Pulmonary-Gas Exchange: an Experimental Study

    PubMed Central

    Antonelli, Raíssa Quaiatti; Moreira, Marcos Mello; Martins, Luiz Claudio; Negro, Maíra Soliani Del; Baldasso, Tiago Antonio; Tincani, Alfio José

    2015-01-01

    OBJECTIVE Mechanical ventilation is frequently necessary, in which case the use of an endotracheal tube is mandatory. The tube has an inflatable balloon in its distal extremity, whose aim is, among other functions, an efficient arterialization. However, serious injuries in the place of contact of the balloon with the trachea can be frequent. Some studies point out that balloons with permanent pressure may reduce this complication. Nevertheless, air scape, expressed by the inspiratory (IV) and expiratory volume (EV) variation (Δ IV-EV), may occur, possibly leading to hypoxemia. Thus, the goal of this study was to verify the efficiency of a modified endotracheal tube on arterializations compared to the traditional endotracheal tube. METHODS The modified endotracheal tube presents intermittent insufflation, with three drillings in the internal region of the cuff, allowing for insufflation in the inspiratory phase of the mechanical ventilation. Three animals were used for the control group, with a cuff pressure of 30 cmH2O, and seven pigs had the modified endotracheal tube. Each animal was kept under mechanical ventilation (FIO2=0.21) for 6 hours. Arterial and venous gases were measured every three hours (T0; T3; T6). RESULTS The gases confirmed the lack of hypoxia between the Groups, with a difference in the ΔIV-EV at T0 (P=0.0486). CONCLUSIONS In this study, the lack of hypoxia showed the efficiency of the modified endotracheal tube. However, new studies are necessary, particularly in diseased lungs, in order to evaluate the real efficiency of the mentioned device on the pulmonary gas exchange. PMID:26934410

  16. Does dimethyl sulfoxide increase protein immunomarking efficiency for dispersal and predation studies?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marking biological control agents facilitates studies of dispersal and predation. This study examines the effect of a biological solvent, dimethyl sulfoxide (DMSO), on retention of immunoglobulin G (IgG) protein solutions applied to Diorhabda carinulata (Desbrochers) (Coleoptera: Chrysomelidae) eit...

  17. STUDY TO IDENTIFY IMPORTANT PARAMETERS FOR CHARACTERIZING PESTICIDE RESIDUE TRANSFER EFFICIENCIES

    EPA Science Inventory

    To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to identify the important parameters for...

  18. Soil Segregation technology: reducing uncertainty and increasing efficiency during radiological decommissioning - a case study

    SciTech Connect

    Lombardo, A.J.; Orthen, R.F.; Shonka, J.J.; Scott, L.M.

    2007-07-01

    the segregation system and the as-left configuration of the refilled excavation, the end state model of the site was prepared with substantially reduced uncertainty. The major projected benefits of this approach are reviewed as well as the performance of the segregation system and lessons learned including: 1) Total, first-attempt data discovery brought about by simultaneously conducted characterization and final status surveys, 2) Lowered project costs stemming from efficient analysis and abstraction of impacted material and reduced offsite waste disposal volume, 3) Lowered project costs due to increased remediation/construction efficiency and decreased survey and radio-analytical expenses, and 4) Improving the decommissioning experience with new regulatory guidance. (authors)

  19. Study of a high efficiency optical MEMS transducer for the generation of narrowband laser ultrasound

    NASA Astrophysics Data System (ADS)

    Chen, Xuesheng; Stratoudaki, Theodosia; Sharples, Steve D.; Clark, Matt

    2010-03-01

    In this paper we demonstrate an optically powered ultrasonic t ransducer. It has a high efficiency and was designed and fabricated using MEMS (microelectromechanical system) techniques. It can generate narrowband ultrasound from broadband laser excitation. It is a simple two-mask-level MEMS device with a micro-disc seated on a micro-stem. As a laser pulse is incident on the disc centre, the disc is excited into a 'flapping' motion because of the thermomechanical interaction between the absorbing and non-absorbing parts of the disc. This flapping motion is dominated by one of the resonances of the disc, coupling a narrowband longitudinal bulk wave propagating along the axis of the micro-stem into the sample. Experiments with these transducers have shown that narrowband ultrasonic waves with a high SNR (signal to noise ratio) were generated successfully. The device is simple to excite optically and generates higher amplitudes than by normal thermoelastic generation. No physical contact is required to excite the transducer, making it suitable for remote non-contact ultrasonic applications.

  20. Theoretical study on a series of iridium complexes with low efficiency roll-off property.

    PubMed

    Song, Ming-Xing; Wang, Guo-Feng; Wang, Jin; Wang, Yu-Hai; Bai, Fu-Quan; Qin, Zheng-Kun

    2015-01-01

    A series of heteroleptic cyclometalated Ir (III) complexes for OLEDs application have been investigated theoretically to explore their electronic structures and spectroscopic properties. The geometries, electronic structures, and the lowest-lying singlet absorptions and triplet emissions of (piq)₂Ir(acac) (labeled 1) and theoretically designed models (piq)₂Ir(dpis) (labeled 2), (4Fpiq)₂Ir(dpis) (labeled 3), (4F5M-piq)₂Ir(dpis) (labeled 4), (4,5-2F-piq)₂Ir(dpis) (labeled 5) and (5-F-piq)₂Ir(dpis) (labeled 6) were investigated with density functional theory (DFT)-based approaches, where, piq=1-phenylisoquinolato, acac=acetylacetonate and dpis=diphenylimidodisilicate. Their structures in the ground and excited states have been optimized at the DFT/B3LYP/LANL2DZ and TDDFT/B3LYP/LANL2DZ levels, and the lowest absorptions and emissions were evaluated at B3LYP and M062X level of theory, respectively. Furthermore, the energy-transfer mechanism of these complexes also be analyzed here, and the result shown that the complexes 1-6 are having the low efficiency roll-off property. Except that, the oscillator strength analyze shown that the complexes 2-6, which were designed by theory, are suitable for OLED since their high oscillator strength property. PMID:25025313

  1. Microsaccades enable efficient synchrony-based coding in the retina: a simulation study

    PubMed Central

    Masquelier, Timothée; Portelli, Geoffrey; Kornprobst, Pierre

    2016-01-01

    It is now reasonably well established that microsaccades (MS) enhance visual perception, although the underlying neuronal mechanisms are unclear. Here, using numerical simulations, we show that MSs enable efficient synchrony-based coding among the primate retinal ganglion cells (RGC). First, using a jerking contrast edge as stimulus, we demonstrate a qualitative change in the RGC responses: synchronous firing, with a precision in the 10 ms range, only occurs at high speed and high contrast. MSs appear to be sufficiently fast to be able reach the synchronous regime. Conversely, the other kinds of fixational eye movements known as tremor and drift both hardly synchronize RGCs because of a too weak amplitude and a too slow speed respectively. Then, under natural image stimulation, we find that each MS causes certain RGCs to fire synchronously, namely those whose receptive fields contain contrast edges after the MS. The emitted synchronous spike volley thus rapidly transmits the most salient edges of the stimulus, which often constitute the most crucial information. We demonstrate that the readout could be done rapidly by simple coincidence-detector neurons without knowledge of the MS landing time, and that the required connectivity could emerge spontaneously with spike timing-dependent plasticity. PMID:27063867

  2. Combinatorial fabrication and studies of intense efficient ultraviolet--violet organic light-emitting device arrays

    SciTech Connect

    Zou, L.; Savvate'ev, V.; Booher, J.; Kim, C.-H.; Shinar, J.

    2001-10-01

    Arrays of ultraviolet--violet (indium tin oxide)/[copper phthalocyanine (CuPc)]/[4,4'-bis(9-carbazolyl)biphenyl (CBP)]/[2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4oxadiazole (Bu-PBD)]/CsF/Al organic light-emitting devices, fabricated combinatorially using a sliding shutter technique, are described. Comparison of the OLED electroluminescence and CBP photoluminescence spectra indicates that the emission originates from the bulk of that layer. In arrays of devices in which the thickness of the CuPc and Bu--PBD were varied, but that of CBP was fixed at 50 nm, the optimal radiance R was obtained at CuPc and Bu--PBD thicknesses of 15 and 18 nm, respectively. At 10 mA/cm{sup 2}, R was 0.38 mW/cm{sup 2}, i.e., the external quantum efficiency was 1.25%; R increased to {approx}1.2 mW/cm{sup 2} at 100 mA/cm{sup 2}.

  3. Study of displacement efficiency and flow behavior of foamed gel in non-homogeneous porous media.

    PubMed

    Wang, Yanling; Jin, Jiafeng; Bai, Baojun; Wei, Mingzhen

    2015-01-01

    Field trials have demonstrated that foamed gel is a very cost-effective technology for profile modification and water shut-off. However, the mechanisms of profile modification and flow behavior of foamed gel in non-homogeneous porous media are not yet well understood. In order to investigate these mechanisms and the interactions between foamed gel and oil in porous media, coreflooding and pore-scale visualization waterflooding experiments were performed in the laboratory. The results of the coreflooding experiment in non-homogeneous porous media showed that the displacement efficiency improved by approximately 30% after injecting a 0.3 pore volume of foamed gel, and was proportional to the pore volumes of the injected foamed gel. Additionally, the mid-high permeability zone can be selectively plugged by foamed gel, and then oil located in the low permeability zone will be displaced. The visualization images demonstrated that the amoeba effect and Jamin effect are the main mechanisms for enhancing oil recovery by foamed gel. Compared with conventional gel, a unique benefit of foamed gel is that it can pass through micropores by transforming into arbitrary shapes without rupturing, this phenomenon has been named the amoeba effect. Additionally, the stability of foam in the presence of crude oil also was investigated. Image and statistical analysis showed that these foams boast excellent oil resistance and elasticity, which allows them to work deep within formations. PMID:26030282

  4. Microsaccades enable efficient synchrony-based coding in the retina: a simulation study.

    PubMed

    Masquelier, Timothée; Portelli, Geoffrey; Kornprobst, Pierre

    2016-01-01

    It is now reasonably well established that microsaccades (MS) enhance visual perception, although the underlying neuronal mechanisms are unclear. Here, using numerical simulations, we show that MSs enable efficient synchrony-based coding among the primate retinal ganglion cells (RGC). First, using a jerking contrast edge as stimulus, we demonstrate a qualitative change in the RGC responses: synchronous firing, with a precision in the 10 ms range, only occurs at high speed and high contrast. MSs appear to be sufficiently fast to be able reach the synchronous regime. Conversely, the other kinds of fixational eye movements known as tremor and drift both hardly synchronize RGCs because of a too weak amplitude and a too slow speed respectively. Then, under natural image stimulation, we find that each MS causes certain RGCs to fire synchronously, namely those whose receptive fields contain contrast edges after the MS. The emitted synchronous spike volley thus rapidly transmits the most salient edges of the stimulus, which often constitute the most crucial information. We demonstrate that the readout could be done rapidly by simple coincidence-detector neurons without knowledge of the MS landing time, and that the required connectivity could emerge spontaneously with spike timing-dependent plasticity. PMID:27063867

  5. Efficiency Study of a Commercial Thermoelectric Power Generator (TEG) Under Thermal Cycling

    NASA Astrophysics Data System (ADS)

    Hatzikraniotis, E.; Zorbas, K. T.; Samaras, I.; Kyratsi, Th.; Paraskevopoulos, K. M.

    2010-09-01

    Thermoelectric generators (TEGs) make use of the Seebeck effect in semiconductors for the direct conversion of heat to electrical energy. The possible use of a device consisting of numerous TEG modules for waste heat recovery from an internal combustion (IC) engine could considerably help worldwide efforts towards energy saving. However, commercially available TEGs operate at temperatures much lower than the actual operating temperature range in the exhaust pipe of an automobile, which could cause structural failure of the thermoelectric elements. Furthermore, continuous thermal cycling could lead to reduced efficiency and lifetime of the TEG. In this work we investigate the long-term performance and stability of a commercially available TEG under temperature and power cycling. The module was subjected to sequential hot-side heating (at 200°C) and cooling for long times (3000 h) in order to measure changes in the TEG’s performance. A reduction in Seebeck coefficient and an increase in resistivity were observed. Alternating-current (AC) impedance measurements and scanning electron microscope (SEM) observations were performed on the module, and results are presented and discussed.

  6. Strategies and Challenges for Energy Efficient Retrofitting: Study of the Empire State Building

    NASA Astrophysics Data System (ADS)

    De, B.; Mukherjee, M.

    2013-11-01

    Operational and maintenance cost of existing buildings is escalating making it tough for both the owner and the tenants. Retrofitting them with state of the art technologies help them to keep pace with amended recent code provisions and thus extending the older building stocks one more chance to live responsively. Retrofitted iconic buildings can thus retain their status in commerce driven real estate sector. It helps in reducing green house gas emission as well. World's iconic skyscraper, the Empire State Building (ESB), has undergone an exemplary retrofit process since 2008 to reduce its energy demands. To achieve the goal of operational cost and energy consumption reduction, stiff challenges had taken care in a systematic manner to realize benefit throughout the entire lifespan of the ESB. Least disturbances to the tenant and on-site component handling strategies required precise planning. The present paper explores strategies and process adopted for retrofitting the ESB, and derived insightful guidelines towards operational cost savings and energy efficiency of existing buildings through retrofitting.

  7. A Computational Study of Energy Efficiency and Pressure Losses in the Total Cavopulmonary Connection

    NASA Astrophysics Data System (ADS)

    Marsden, Alison

    2005-11-01

    The total cavopulmonary connection (TCPC) is an operation performed to treat single ventricle congenital heart defects. The superior and inferior vena cavae are connected to the pulmonary arteries in a t-shaped junction, separating the systemic and pulmonary circulations. In this work, we hypothesize that the effects of respiration and exercise cause significant hemodynamic disturbances and energy loss. Time- dependent, 3-D blood flow simulations are performed using a custom finite element solver and patient specific geometry. Blood flow features, pressure, and energy losses are analyzed at rest and with increasing flow rates to simulate exercise conditions. Resistance boundary conditions are enforced at the pulmonary artery outlets. Energy efficiency is high at rest but drops substantially with maximal exercise. Flow vortices increase in intensity with respiration and exercise, explaining higher energy dissipation when compared to rest. Pressure drop and energy loss in the TCPC are small at rest but increase to significant levels, even at moderate exercise. We conclude that the effects of respiration and exercise should be incorporated in models to provide realistic evaluations of TCPC performance, and for future work in optimizing TCPC geometry.

  8. Computationally efficient modeling of proprioceptive signals in the upper limb for prostheses: a simulation study

    PubMed Central

    Williams, Ian; Constandinou, Timothy G.

    2014-01-01

    Accurate models of proprioceptive neural patterns could 1 day play an important role in the creation of an intuitive proprioceptive neural prosthesis for amputees. This paper looks at combining efficient implementations of biomechanical and proprioceptor models in order to generate signals that mimic human muscular proprioceptive patterns for future experimental work in prosthesis feedback. A neuro-musculoskeletal model of the upper limb with 7 degrees of freedom and 17 muscles is presented and generates real time estimates of muscle spindle and Golgi Tendon Organ neural firing patterns. Unlike previous neuro-musculoskeletal models, muscle activation and excitation levels are unknowns in this application and an inverse dynamics tool (static optimization) is integrated to estimate these variables. A proprioceptive prosthesis will need to be portable and this is incompatible with the computationally demanding nature of standard biomechanical and proprioceptor modeling. This paper uses and proposes a number of approximations and optimizations to make real time operation on portable hardware feasible. Finally technical obstacles to mimicking natural feedback for an intuitive proprioceptive prosthesis, as well as issues and limitations with existing models, are identified and discussed. PMID:25009463

  9. Three-wavelength light control of freely moving Drosophila Melanogaster for less perturbation and efficient social-behavioral studies

    PubMed Central

    Lin, Yen-Yin; Wu, Ming-Chin; Hsiao, Po-Yen; Chu, Li-An; Yang, Mei-Mei; Fu, Chien-Chung; Chiang, Ann-Shyn

    2015-01-01

    We developed a real-time automated laser-tracking system combined with continuous wave 1064-nm infrared or 473-nm blue lasers to provide punishment for studying memory in Drosophila Melanogaster. Combining optogenetic tools with laser properties, such as 473-nm and 593-nm lasers that activate light sensitive proteins in artificial transgenic flies, we can manipulate the specific neuron of an assigned fly among multiple flies to investigate neuron circuit relationships in social interactions. In restraining condition assay or optogenetic experiments, a ventral irradiated system would be more efficient due to higher ventral cuticle transmissions and neuron ganglia locations. Therefore, ventral irradiated systems cause less perturbation during behavior studies. PMID:25780741

  10. Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

    NASA Technical Reports Server (NTRS)

    Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

    1987-01-01

    A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

  11. Comparative study of the efficiency of synthetic and natural mediators in laccase-assisted bleaching of eucalyptus kraft pulp.

    PubMed

    Moldes, D; Díaz, M; Tzanov, T; Vidal, T

    2008-11-01

    The natural phenolic compounds syringaldehyde and vanillin were compared to the synthetic mediators 1-hydroxybenzotriazole, violuric acid and promazine in terms of boosting efficiency in a laccase-assisted biobleaching of eucalyptus kraft pulp. Violuric acid and 1-hydroxybenzotriazole revealed to be the most effective mediators of the bioprocess. Nevertheless, laccase-syringaldehyde system also improved the final pulp properties (28% delignification and 63.5% ISO brightness) compared to the process without mediator (23% and 61.5% respectively), in addition to insignificant denaturation effect over laccase. The efficiency of the biobleaching process was further related to changes in non-conventionally used optical and chromatic parameters of pulp, such as (L*), chroma (C*) and dye removal index (DRI) showing good correlation. Adverse coupling reactions of the natural phenolic mediators on pulp lignin were predicted by electrochemical studies, demonstrating the complexity of the laccase-mediator reaction on pulp. PMID:18499450

  12. Theoretical study of inhibition efficiencies of some amino acids on corrosion of carbon steel in acidic media: green corrosion inhibitors.

    PubMed

    Dehdab, Maryam; Shahraki, Mehdi; Habibi-Khorassani, Sayyed Mostafa

    2016-01-01

    Inhibition efficiencies of three amino acids [tryptophan (B), tyrosine (c), and serine (A)] have been studied as green corrosion inhibitors on corrosion of carbon steel using density functional theory (DFT) method in gas and aqueous phases. Quantum chemical parameters such as EH OMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), hardness (η), polarizability ([Formula: see text]), total negative charges on atoms (TNC), molecular volume (MV) and total energy (TE) have been calculated at the B3LYP level of theory with 6-311++G** basis set. Consistent with experimental data, theoretical results showed that the order of inhibition efficiency is tryptophan (B) > tyrosine (C) > serine (A). In order to determine the possible sites of nucleophilic and electrophilic attacks, local reactivity has been evaluated through Fukui indices. PMID:26347374

  13. Study of a prototype high quantum efficiency thick scintillation crystal video-electronic portal imaging device

    SciTech Connect

    Samant, Sanjiv S.; Gopal, Arun

    2006-08-15

    Image quality in portal imaging suffers significantly from the loss in contrast and spatial resolution that results from the excessive Compton scatter associated with megavoltage x rays. In addition, portal image quality is further reduced due to the poor quantum efficiency (QE) of current electronic portal imaging devices (EPIDs). Commercial video-camera-based EPIDs or VEPIDs that utilize a thin phosphor screen in conjunction with a metal buildup plate to convert the incident x rays to light suffer from reduced light production due to low QE (<2% for Eastman Kodak Lanex Fast-B). Flat-panel EPIDs that utilize the same luminescent screen along with an a-Si:H photodiode array provide improved image quality compared to VEPIDs, but they are expensive and can be susceptible to radiation damage to the peripheral electronics. In this article, we present a prototype VEPID system for high quality portal imaging at sub-monitor-unit (subMU) exposures based on a thick scintillation crystal (TSC) that acts as a high QE luminescent screen. The prototype TSC system utilizes a 12 mm thick transparent CsI(Tl) (thallium-activated cesium iodide) scintillator for QE=0.24, resulting in significantly higher light production compared to commercial phosphor screens. The 25x25 cm{sup 2} CsI(Tl) screen is coupled to a high spatial and contrast resolution Video-Optics plumbicon-tube camera system (1240x1024 pixels, 250 {mu}m pixel width at isocenter, 12-bit ADC). As a proof-of-principle prototype, the TSC system with user-controlled camera target integration was adapted for use in an existing clinical gantry (Siemens BEAMVIEW{sup PLUS}) with the capability for online intratreatment fluoroscopy. Measurements of modulation transfer function (MTF) were conducted to characterize the TSC spatial resolution. The measured MTF along with measurements of the TSC noise power spectrum (NPS) were used to determine the system detective quantum efficiency (DQE). A theoretical expression of DQE(0) was

  14. Study of a prototype high quantum efficiency thick scintillation crystal video-electronic portal imaging device.

    PubMed

    Samant, Sanjiv S; Gopal, Arun

    2006-08-01

    Image quality in portal imaging suffers significantly from the loss in contrast and spatial resolution that results from the excessive Compton scatter associated with megavoltage x rays. In addition, portal image quality is further reduced due to the poor quantum efficiency (QE) of current electronic portal imaging devices (EPIDs). Commercial video-camera-based EPIDs or VEPIDs that utilize a thin phosphor screen in conjunction with a metal buildup plate to convert the incident x rays to light suffer from reduced light production due to low QE (<2% for Eastman Kodak Lanex Fast-B). Flat-panel EPIDs that utilize the same luminescent screen along with an a-Si:H photodiode array provide improved image quality compared to VEPIDs, but they are expensive and can be susceptible to radiation damage to the peripheral electronics. In this article, we present a prototype VEPID system for high quality portal imaging at sub-monitor-unit (subMU) exposures based on a thick scintillation crystal (TSC) that acts as a high QE luminescent screen. The prototype TSC system utilizes a 12 mm thick transparent CsI(Tl) (thallium-activated cesium iodide) scintillator for QE=0.24, resulting in significantly higher light production compared to commercial phosphor screens. The 25 X 25 cm2 CsI(Tl) screen is coupled to a high spatial and contrast resolution Video-Optics plumbicon-tube camera system (1240 X 1024 pixels, 250 microm pixel width at isocenter, 12-bit ADC). As a proof-of-principle prototype, the TSC system with user-controlled camera target integration was adapted for use in an existing clinical gantry (Siemens BEAMVIEW(PLUS)) with the capability for online intratreatment fluoroscopy. Measurements of modulation transfer function (MTF) were conducted to characterize the TSC spatial resolution. The measured MTF along with measurements of the TSC noise power spectrum (NPS) were used to determine the system detective quantum efficiency (DQE). A theoretical expression of DQE(0) was developed

  15. Study of the detective quantum efficiency for the kinestatic charge detector as a megavoltage imaging device

    NASA Astrophysics Data System (ADS)

    Samant, Sanjiv S.; Gopal, Arun; DiBianca, Frank A.

    2003-06-01

    Megavoltage x-ray imaging suffers from relatively poor contrast and spatial resolution compared to diagnostic kilovoltage x-ray imaging due to the dominant Compton scattering in the former. Recently available amorphous silicon/selenium based flat-panel imagers overcome many of the limitations of poor contrast and spatial resolution that affect conventional video based electronic portal imaging devices (EPIDs). An alternative technology is presented here: kinestatic charge detection (KCD). The KCD uses a slot photon beam, high-pressure gas (xenon, 100 atm) and a multi-ion rectangular chamber in scanning mode. An electric field is used to regulate the cation drift velocity. By matching the scanning speed with that of the cation drift, the cations remain static in the object frame of reference, allowing temporal integration of the signal. KCD imaging is characterized by reduced scatter and a high signal-to-noise ratio. Measurements and Monte Carlo simulations of modulation transfer function (MTF), noise power spectrum (NPS) and the detective quantum efficiency (DQE) of a prototype small field of view KCD detector (384 channels, 0.5 mm spacing) were carried out. Measurements yield DQE[0]=0.19 and DQE[0.5cy/mm]=0.01. KCD imaging is compared to film and commercial EPID systems using phantoms, with the KCD requiring an extremely low dose (0.1 cGy) per image. A proposed cylindrical chamber design with a higher ion-collection depth is expected to further improve image quality (DQE[0]>0.25).

  16. Study of Highly Selective and Efficient Thiol Derivatization using Selenium Reagents by Mass Spectrometry

    SciTech Connect

    Xu, Kehua; Zhang, Yun W.; Tang, Bo; Laskin, Julia; Roach, Patrick J.; Chen, Hao

    2010-08-15

    Biological thiols are critical physiological components and their detection often involves derivatization. This paper reports a systemic mass spectrometry (MS) investigation of the cleavage of Se-N bond by thiol to form a new Se-S bond, the new selenium chemistry for thiol labeling. Our data shows that the reaction is highly selective, rapid, reversible and efficient. For instance, among twenty amino acids, only cysteine was found to be reactive with Se-N containing reagents and the reaction takes place in seconds. By adding dithiothreitol (DTT), the newly formed Se-S bond of peptides/proteins can be reduced back to free thiol. The high selectivity and excellent reversibility of the reaction provide potential of using this chemistry for selective identification of thiol compounds or enriching and purifying thiol peptides/proteins. In addition, the derivatized thiol peptides have interesting dissociation behavior, which is tunable using different selenium reagents. For example, by introducing an adjacent nucleophilic group into the selenium reagent in the case of using ebselen, the reaction product of ebselen with glutathione (GSH) is easy to lose the selenium tag upon collision-induced dissociation (CID), which is useful to "fish out" those peptides containing free cysteine residues by precursor ion scan. By contrast, the selenium tag of N-(phenylseleno) phthalimide reagent can be stable and survive in CID process, which would be of value in pinpointing thiol location using a top-down proteomic approach. Also, the high conversion yield of the reaction allows the counting of total number of thiol in proteins. We believe that ebselen or N-(phenylseleno) phthalimide as tagging thiol-protein reagents will have important applications in both qualitative and quantitative analysis of different thiol-proteins derived from living cells by MS method.

  17. Evaluation of the endotoxin binding efficiency of clay minerals using the Limulus Amebocyte lysate test: an in vitro study

    PubMed Central

    2014-01-01

    Endotoxins are part of the cell wall of Gram-negative bacteria. They are potent immune stimulators and can lead to death if present in high concentrations. Feed additives, which bind endotoxins in the gastrointestinal tract of animals, could help to prevent their negative impact. The objective of our study was to determine the potential of a bentonite (Bentonite 1), a sodium bentonite (Bentonite 2), a chemically treated smectite (Organoclay 1) and a modified attapulgite (Organoclay 2) to bind endotoxins in vitro. Polymyxin B served as positive control. The kinetic chromogenic Limulus Amebocyte lysate test was adapted to measure endotoxin activity. Firstly, a single sorption experiment (10 endotoxin units/mL (EU/mL)) was performed. Polymyxin B and organoclays showed 100% binding efficiency. Secondly, the adsorption efficiency of sorbents in aqueous solution with increasing endotoxin concentrations (2,450 – 51,700 EU/mL) was investigated. Organoclay 1 (0.1%) showed a good binding efficiency in aqueous solution (average 81%), whereas Bentonite 1 (0.1%) obtained a lower binding efficiency (21-54%). The following absorbent capacities were calculated in highest endotoxin concentration: 5.59 mg/g (Organoclay 1) > 3.97 mg/g (Polymyxin B) > 2.58mg/g (Organoclay 2) > 1.55 mg/g (Bentonite 1) > 1.23 mg/g (Bentonite 2). Thirdly, a sorption experiment in artificial intestinal fluid was conducted. Especially for organoclays, which are known to be unspecific adsorbents, the endotoxin binding capacity was significantly reduced. In contrast, Bentonite 1 showed comparable results in artificial intestinal fluid and aqueous solution. Based on the results of this in vitro study, the effect of promising clay minerals will be investigated in in vivo trials. PMID:24383578

  18. 111In- and 203Pb-Labeled Cyclic RGD Peptide Conjugate as an αvβ3 Integrin-Binding Radiotracer

    PubMed Central

    Nwe, Kido; Kim, Young-Seung; Milenic, Diane E.; Baidoo, Kwamena E.; Brechbiel, Martin W.

    2012-01-01

    Methodology for site-specific modification and chelate conjugation of a cyclic RGD (cRGD) peptide for the preparation of a radiotracer molecular imaging agent suitable for detecting αvβ3 integrin is described. The method involves functionalizing the peptide with an aldehyde moiety and conjugation to a 1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid (DOTA) derivative that possesses an aldehyde reactive aminooxy group. The binding assay of the 111In-labeled peptide conjugate with αvβ3 integrin showed 60% bound when four equivalents of the integrin was added, a reasonable binding affinity for a mono-valent modified RGD peptide. PMID:23162207

  19. Inappropriate Intra-cervical Injection of Radiotracer for Sentinel Lymph Node Mapping in a Uterine Cervix Cancer Patient: Importance of Lymphoscintigraphy and Blue Dye Injection

    PubMed Central

    Kadkhodayan, Sima; Farahabadi, Elham Hosseini; Yousefi, Zohreh; Hasanzadeh, Malihe; Sadeghi, Ramin

    2014-01-01

    Herein, we report a case of sentinel lymph node mapping in a uterine cervix cancer patient, referring to the nuclear medicine department of our institute. Lymphoscintigraphy images showed inappropriate intra-cervical injection of radiotracer. Blue dye technique was applied for sentinel lymph node mapping, using intra-cervical injection of methylene blue. Two blue/cold sentinel lymph nodes, with no pathological involvement, were intra-operatively identified, and the patient was spared pelvic lymph node dissection. The present case underscores the importance of lymphoscintigraphy imaging in sentinel lymph node mapping and demonstrates the added value of blue dye injection in selected patients. It is suggested that pre-operative lymphoscintigraphy imaging be considered as an integral part of sentinel lymph node mapping in surgical oncology. Detailed results of lymphoscintigraphy images should be provided for surgeons prior to surgery, and in case the sentinel lymph nodes are not visualized, use of blue dye for sentinel node mapping should be encouraged.

  20. Inappropriate Intra-cervical Injection of Radiotracer for Sentinel Lymph Node Mapping in a Uterine Cervix Cancer Patient: Importance of Lymphoscintigraphy and Blue Dye Injection.

    PubMed

    Kadkhodayan, Sima; Farahabadi, Elham Hosseini; Yousefi, Zohreh; Hasanzadeh, Malihe; Sadeghi, Ramin

    2014-01-01

    Herein, we report a case of sentinel lymph node mapping in a uterine cervix cancer patient, referring to the nuclear medicine department of our institute. Lymphoscintigraphy images showed inappropriate intra-cervical injection of radiotracer. Blue dye technique was applied for sentinel lymph node mapping, using intra-cervical injection of methylene blue. Two blue/cold sentinel lymph nodes, with no pathological involvement, were intra-operatively identified, and the patient was spared pelvic lymph node dissection. The present case underscores the importance of lymphoscintigraphy imaging in sentinel lymph node mapping and demonstrates the added value of blue dye injection in selected patients. It is suggested that pre-operative lymphoscintigraphy imaging be considered as an integral part of sentinel lymph node mapping in surgical oncology. Detailed results of lymphoscintigraphy images should be provided for surgeons prior to surgery, and in case the sentinel lymph nodes are not visualized, use of blue dye for sentinel node mapping should be encouraged. PMID:27408871

  1. Synthesis and biological evaluation of positron emission tomography radiotracers targeting serotonin 4 receptors in brain: [18F]MNI-698 and [18F]MNI-699.

    PubMed

    Caillé, Fabien; Morley, Thomas J; Tavares, Adriana Alexandre S; Papin, Caroline; Twardy, Nicole M; Alagille, David; Lee, H Sharon; Baldwin, Ronald M; Seibyl, John P; Barret, Olivier; Tamagnan, Gilles D

    2013-12-01

    Two new benzodioxane derivatives were synthesized as candidates to image the serotonin 4 receptors by positron emission tomography (PET) and radiolabeled with fluorine-18 via a two-step procedure. Competition binding assays demonstrated that MNI-698 and MNI-699 had sub-nanomolar binding affinities against rat striatal 5-HT4 receptors (Ki of 0.20 and 0.07 nM, respectively). PET imaging in rhesus monkey showed that the regional brain distribution of [(18)F]MNI-698 and [(18)F]MNI-699 were consistent with the known densities of 5-HT4 in brain. [(18)F]MNI-698 and [(18)F]MNI-699 are among the first fluorine-18 radiotracers developed for imaging the 5-HT4 receptors in vivo and are currently under preclinical investigation in primates for future human use. PMID:24157369

  2. Shuttle Ground Operations Efficiencies/Technologies (SGOE/T) study. Volume 2: Ground Operations evaluation

    NASA Technical Reports Server (NTRS)

    Scholz, A. L.; Hart, M. T.; Lowry, D. J.

    1987-01-01

    The Ground Operations Evaluation describes the breath and depth of the various study elements selected as a result of an operational analysis conducted during the early part of the study. Analysis techniques used for the evaluation are described in detail. Elements selected for further evaluation are identified; the results of the analysis documented; and a follow-on course of action recommended. The background and rationale for developing recommendations for the current Shuttle or for future programs is presented.

  3. Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device

    SciTech Connect

    Peng, S.Y.

    1991-07-01

    Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system ({rho},{xi}) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number {alpha} as well as the complete EM fields. The computational study involves a multiple eigenmode computational analysis of the fields that exist within the plasma-vacuum system. The inhomogeneous axial field is treated by dividing the geometry into a series of transverse axial slices and using a constant dielectric tensor in each individual slice. The slices are then connected by longitudinal boundary conditions.

  4. Evaluation of two spike-and-recovery controls for assessment of extraction efficiency in microbial source tracking studies.

    PubMed

    Stoeckel, Donald M; Stelzer, Erin A; Dick, Linda K

    2009-11-01

    Quantitative PCR (qPCR), applied to complex environmental samples such as water, wastewater, and feces, is susceptible to methodological and sample related biases. In this study, we evaluated two exogenous DNA spike-and-recovery controls as proxies for recovery efficiency of Bacteroidales 16S rDNA gene sequences (AllBac and qHF183) that are used for microbial source tracking (MST) in river water. Two controls--(1) the plant pathogen Pantoea stewartii, carrying the chromosomal target gene cpsD, and (2) Escherichia coli, carrying the plasmid-borne target gene DsRed2--were added to raw water samples immediately prior to concentration and DNA extraction for qPCR. When applied to samples processed in replicate, recovery of each control was positively correlated with the observed concentration of each MST marker. Adjustment of MST marker concentrations according to recovery efficiency reduced variability in replicate analyses when consistent processing and extraction methodologies were applied. Although the effects of this procedure on accuracy could not be tested due to uncertainties in control DNA concentrations, the observed reduction in variability should improve the strength of statistical comparisons. These findings suggest that either of the tested spike-and-recovery controls can be useful to measure efficiency of extraction and recovery in routine laboratory processing. PMID:19589555

  5. Factors influencing the ablative efficiency of high intensity focused ultrasound (HIFU) treatment for adenomyosis: A retrospective study.

    PubMed

    Gong, Chunmei; Yang, Bin; Shi, Yarong; Liu, Zhongqiong; Wan, Lili; Zhang, Hong; Jiang, Denghua; Zhang, Lian

    2016-08-01

    Objectives The aim of this study was to investigate factors affecting ablative efficiency of high intensity focused ultrasound (HIFU) for adenomyosis. Materials and methods In all, 245 patients with adenomyosis who underwent ultrasound guided HIFU (USgHIFU) were retrospectively reviewed. All patients underwent dynamic contrast-enhanced magnetic resonance imaging (MRI) before and after HIFU treatment. The non-perfused volume (NPV) ratio, energy efficiency factor (EEF) and greyscale change were set as dependent variables, while the factors possibly affecting ablation efficiency were set as independent variables. These variables were used to build multiple regression models. Results A total of 245 patients with adenomyosis successfully completed HIFU treatment. Enhancement type on T1 weighted image (WI), abdominal wall thickness, volume of adenomyotic lesion, the number of hyperintense points, location of the uterus, and location of adenomyosis all had a linear relationship with the NPV ratio. Distance from skin to the adenomyotic lesion's ventral side, enhancement type on T1WI, volume of adenomyotic lesion, abdominal wall thickness, and signal intensity on T2WI all had a linear relationship with EEF. Location of the uterus and abdominal wall thickness also both had a linear relationship with greyscale change. Conclusion The enhancement type on T1WI, signal intensity on T2WI, volume of adenomyosis, location of the uterus and adenomyosis, number of hyperintense points, abdominal wall thickness, and distance from the skin to the adenomyotic lesion's ventral side can all be used as predictors of HIFU for adenomyosis. PMID:27385316

  6. COD, nutrient removal and disinfection efficiency of a combined subsurface and surface flow constructed wetland: A case study.

    PubMed

    Sartori, Laura; Canobbio, Sergio; Fornaroli, Riccardo; Cabrini, Riccardo; Marazzi, Francesca; Mezzanotte, Valeria

    2016-01-01

    A constructed wetland system composed of a subsurface flow wetland, a surface flow wetland and a facultative pond was studied from July 2008 until May 2012. It was created to treat the domestic sewage produced by a hamlet of 150 inhabitants. Monthly physicochemical and microbiological analyses were carried out in order to evaluate the removal efficiency of each stage of the process and of the total treatment system. Pair-wise Student's t-tests showed that the mean removal of each considered parameter was significantly different (α = 0.05) between the various treatment phases. Two-way ANOVA and Tukey's HSD tests were used to find significant differences between wetland types and seasons in the removal efficiency of the considered water quality parameters. Significant differences in percent removal efficiency between the treatment phases were observed for total phosphorus, total nitrogen, ammonia nitrogen and organic load (expressed as Chemical Oxygen Demand). In general, the wastewater treatment was carried by the sub-superficial flow phase mainly, both in growing season and in quiescence season. Escherichia coli removal ranged from 98% in quiescence season to >99% in growing season (approximately 2-3 orders of magnitude). The inactivation of fecal bacteria was not influenced by the season, but only by the treatment phase. PMID:26552725

  7. Evaluation of two spike-and-recovery controls for assessment of extraction efficiency in microbial source tracking studies

    USGS Publications Warehouse

    Stoeckel, D.M.; Stelzer, E.A.; Dick, L.K.

    2009-01-01

    Quantitative PCR (qPCR), applied to complex environmental samples such as water, wastewater, and feces, is susceptible to methodological and sample related biases. In this study, we evaluated two exogenous DNA spike-and-recovery controls as proxies for recovery efficiency of Bacteroidales 16S rDNA gene sequences (AllBac and qHF183) that are used for microbial source tracking (MST) in river water. Two controls-(1) the plant pathogen Pantoea stewartii, carrying the chromosomal target gene cpsD, and (2) Escherichia coli, carrying the plasmid-borne target gene DsRed2-were added to raw water samples immediately prior to concentration and DNA extraction for qPCR. When applied to samples processed in replicate, recovery of each control was positively correlated with the observed concentration of each MST marker. Adjustment of MST marker concentrations according to recovery efficiency reduced variability in replicate analyses when consistent processing and extraction methodologies were applied. Although the effects of this procedure on accuracy could not be tested due to uncertainties in control DNA concentrations, the observed reduction in variability should improve the strength of statistical comparisons. These findings suggest that either of the tested spike-and-recovery controls can be useful to measure efficiency of extraction and recovery in routine laboratory processing. ?? 2009 Elsevier Ltd.

  8. Evaluation of efficiency of aircraft liquid waste treatment and identification of daily inspection indices: a case study in Changchun, China.

    PubMed

    Xu, Jianling; Yang, Jiaqi; Zhao, Nan; Sheng, Lianxi; Zhao, Yuanhui; Tang, Zhanhui

    2013-07-01

    Evaluation of the efficiency of aircraft liquid waste treatment has previously been conducted to prevent pollution of the environment. The current study aimed to provide a set of practical methods for efficient airport sanitary supervision. Aircraft liquid waste was collected at Longjia International Airport, Changchun from multiple flights. The efficiency of liquid waste treatment as well as the water quality of the wastewater processed via a second-stage wastewater facility were examined by measuring a number of physical, chemical, and biological indices. Our results indicated that treatment solely via resolvable sanitizing liquid was not sufficient. Although the contents of first-class pollutants all met the requirements of the standard criteria, the contents of a number of second-class pollutants did not satisfy these criteria. However, after further treatment via a second-stage wastewater facility installed at the airport, all indices reached second-grade requirements of the discharge standard. We suggest that daily inspection and quarantine indices at airports should include the suspension content, biological oxygen demands after 5 days, chemical oxygen demand total organic carbon content, amino nitrogen content, total phosphorous content, and the level of fecal coliforms. PMID:23192680

  9. Efficiency of a "small-world" brain network depends on consciousness level: a resting-state FMRI study.

    PubMed

    Uehara, Taira; Yamasaki, Takao; Okamoto, Tsuyoshi; Koike, Takahiko; Kan, Shigeyuki; Miyauchi, Satoru; Kira, Jun-Ichi; Tobimatsu, Shozo

    2014-06-01

    It has been revealed that spontaneous coherent brain activity during rest, measured by functional magnetic resonance imaging (fMRI), self-organizes a "small-world" network by which the human brain could sustain higher communication efficiency across global brain regions with lower energy consumption. However, the state-dependent dynamics of the network, especially the dependency on the conscious state, remain poorly understood. In this study, we conducted simultaneous electroencephalographic recording with resting-state fMRI to explore whether functional network organization reflects differences in the conscious state between an awake state and stage 1 sleep. We then evaluated whole-brain functional network properties with fine spatial resolution (3781 regions of interest) using graph theoretical analysis. We found that the efficiency of the functional network evaluated by path length decreased not only at the global level, but also in several specific regions depending on the conscious state. Furthermore, almost two-thirds of nodes that showed a significant decrease in nodal efficiency during stage 1 sleep were categorized as the default-mode network. These results suggest that brain functional network organizations are dynamically optimized for a higher level of information integration in the fully conscious awake state, and that the default-mode network plays a pivotal role in information integration for maintaining conscious awareness. PMID:23349223

  10. Weak network efficiency in young children with Autism Spectrum Disorder: Evidence from a functional near-infrared spectroscopy study.

    PubMed

    Li, Yanwei; Yu, Dongchuan

    2016-10-01

    Functional near infrared spectroscopy (fNIRS) is particularly suited for the young population and ecological measurement. However, thus far, not enough effort has been given to the clinical diagnosis of young children with Autism Spectrum Disorder (ASD) by using fNIRS. The current study provided some insights into the quantitative analysis of functional networks in young children (ages 4.8-8.0years old) with and without ASD and, in particular, investigated the network efficiency and lobe-level connectivity of their functional networks while watching a cartoon. The main results included that: (i) Weak network efficiency was observed in young children with ASD, even for a wide range of threshold for the binarization of functional networks; (ii) A maximum classification accuracy rate of 83.3% was obtained for all participants by using the k-means clustering method with network efficiencies as the feature parameters; and (iii) Weak lobe-level inter-region connections were uncovered in the right prefrontal cortex, including its linkages with the left prefrontal cortex and the bilateral temporal cortex. Such results indicate that the right prefrontal cortex might make a major contribution to the psychopathology of young children with ASD at the functional network architecture level, and at the functional lobe-connectivity level, respectively. PMID:27474793

  11. Shuttle ground operations efficiencies/technologies study. Volume 4: Preliminary Issues Database (PIDB) catalog

    NASA Technical Reports Server (NTRS)

    Scholz, A. L.; Hart, M. T.; Lowry, D. J.

    1987-01-01

    The Preliminary Issues Database (PIDB) was assembled very early in the study as one of the fundamental tools to be used throughout the study. Data was acquired from a variety of sources and compiled in such a way that the data could be easily sorted in accordance with a number of different analytical objectives. The system was computerized to significantly expedite sorting and make it more usable. The information contained in the PIDB is summarized and the reader is provided with the capability to manually find items of interest.

  12. Operationally efficient propulsion system study (OEPSS) data book. Volume 10; Air Augmented Rocket Afterburning

    NASA Technical Reports Server (NTRS)

    Farhangi, Shahram; Trent, Donnie (Editor)

    1992-01-01

    A study was directed towards assessing viability and effectiveness of an air augmented ejector/rocket. Successful thrust augmentation could potentially reduce a multi-stage vehicle to a single stage-to-orbit vehicle (SSTO) and, thereby, eliminate the associated ground support facility infrastructure and ground processing required by the eliminated stage. The results of this preliminary study indicate that an air augmented ejector/rocket propulsion system is viable. However, uncertainties resulting from simplified approach and assumptions must be resolved by further investigations.

  13. Growth, spectral and thermal studies of an efficient NLO material: Diaquadicinnamatocadmium(II)

    SciTech Connect

    Roy, Sunalya M.; Sudarsanakumar, M. R.; Dhanya, V. S.

    2014-01-28

    A nonlinear metal–organic crystal, diaquadicinnamatocadmium(II) has been grown by controlled gel diffusion technique. Sodium metasilicate was used to prepare the gel. The chemical composition of the crystal has been determined by CHN analysis. Powder X-ray diffraction studies confirm the crystalline nature of the grown crystal. Functional groups present in the compound were identified by FT-IR spectral analysis. The thermal decomposition of the compound was studied using thermogravimetry (TG). The optical transparency range and the lower cut-off wavelength were identified from the UV-Visible-NIR spectrum. The NLO activity of the grown crystal was confirmed using Kurtz and Perry powder test.

  14. Performance of manual ventilation: how to define its efficiency in bench studies? A review of the literature.

    PubMed

    Khoury, A; De Luca, A; Sall, F S; Pazart, L; Capellier, G

    2015-08-01

    Bench studies have become the preferred way to evaluate the performance of airway equipment, since clinical trials are not specifically required before marketing these devices. However, it is difficult to assess the efficiency of ventilation without recording physiological data. This review analyses how efficiency of manual ventilation has been defined in recent studies, and how their results may be affected. We searched electronic databases from 2000 to April 2014. The main inclusion criterion was the analysis of performance of ventilation. Nine relevant articles were selected from 53 eligible publications. Most studies used the same parameters; tidal volume and ventilation rate. However, there were significant differences between the definitions of performance of ventilation, both in terms of criteria of judgement and methods of analysis. None of these approaches is able to provide a clear understanding of variability of ventilation during a given period. A new definition may increase the relevance of bench studies to clinical medicine, by more appropriately assessing the performance of ventilation. PMID:25997146

  15. Parametric Study of Up-Conversion Efficiency in Er-Doped Lanthanide Hosts Under 780 nm/980 nm Excitation Wavelengths

    NASA Astrophysics Data System (ADS)

    Samir, E.; Shehata, N.; Aldacher, M.; Kandas, I.

    2016-06-01

    Up-conversion is a process of converting low energy light photons to higher energy ones, which can be extensively used in many applications. This paper presents a detailed parametric study of the up-conversion process under different wavelength excitations—780 nm and 980 nm—showing the optical conversion mechanisms that affect the emitted light quantum yield efficiencies. The studied material is erbium-doped β-NaYF4 material, which is one of the most recently studied materials due to its low phonon energy. The studied simulation considers most processes and possible transitions that can take place between Er3+ ions. Einstein coefficients, which are the main parameters that are responsible for the transitions probabilities, are discussed in detail using Judd-Ofelt analysis. In addition, the effect of changing some parametric values is discussed, showing their optimum values that could improve the quantum yield efficiency. This model is very promising, and generic, and can be applied for any host material under any excitation wavelengths by varying the material-dependent parameters.

  16. Bathroom greywater recycling using polyelectrolyte-complex bilayer membrane: Advanced study of membrane structure and treatment efficiency.

    PubMed

    Oh, K S; Poh, P E; Chong, M N; Chan, E S; Lau, E V; Saint, C P

    2016-09-01

    Polyelectrolyte-complex bilayer membrane (PCBM) was fabricated using biodegradable chitosan and alginate polymers for subsequent application in the treatment of bathroom greywater. In this study, the properties of PCBMs were studied and it was found that the formation of polyelectrolyte network reduced the molecular weight cut-off (MWCO) from 242kDa in chitosan membrane to 2.71kDa in PCBM. The decrease in MWCO of PCBM results in better greywater treatment efficiency, subsequently demonstrated in a greywater filtration study where treated greywater effluent met the household reclaimed water standard of <2 NTU turbidity and <30ppm total suspended solids (TSS). In addition, a further 20% improvement in chemical oxygen demand (COD) removal was achieved as compared to a single layer chitosan membrane. Results from this study show that the biodegradable PCBM is a potential membrane material in producing clean treated greywater for non-potable applications. PMID:27185127

  17. Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope

    SciTech Connect

    Kachulis, Chris; /Yale U. /SLAC

    2011-06-22

    The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope provides charged particle rejection for the Large Area Telescope (LAT). We use two calibrations used by the ACD to conduct three studies on the performance of the ACD. We examine the trending of the calibrations to search for damage and find a timescale over which the calibrations can be considered reliable. We also calculated the number of photoelectrons counted by a PMT on the ACD from a normal proton. Third, we calculated the veto efficiencies of the ACD for two different veto settings. The trends of the calibrations exhibited no signs of damage, and indicated timescales of reliability for the calibrations of one to two years. The number of photoelectrons calculated ranged from 5 to 25. Large errors in the effect of the energy spectrum of the charged particles caused these values to have very large errors of around 60 percent. Finally, the veto efficiencies were found to be very high at both veto values, both for charged particles and for the lower energy backsplash spectrum. The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope is a detector system built around the silicon strip tracker on the Large Area Telescope (LAT). The purpose of the ACD is to provide charged particle rejection for the LAT. To do this, the ACD must be calibrated correctly in flight, and must be able to efficiently veto charged particle events while minimizing false vetoes due to 'backsplash' from photons in the calorimeter. There are eleven calibrations used by the ACD. In this paper, we discuss the use of two of these calibrations to preform three studies on the performance of the ACD. The first study examines trending of the calibrations to check for possible hardware degradation. The second study uses the calibrations to explore the efficiency of an on-board hardware veto. The third study uses the calibrations to calculate the number of photoelectrons seen by each PMT when a minimum ionizing

  18. Study of the Effectiveness and Efficiency of Charter Schools in Indiana. Special Report

    ERIC Educational Resources Information Center

    Akey, Terri; Plucker, Jonathan A.; Hansen, John A.; Michael, Robert; Branon, Suzanne; Fagen, Rebecca; Zhou, Zejun

    2009-01-01

    In July of 2007, the Center for Evaluation and Education Policy (CEEP) at Indiana University was contracted by the state legislature to conduct an evaluation of the Indiana charter schools. The current study reports the results of an evaluation that has been designed to ensure that all objectives of the provisions of HEA 1001-2007 are fulfilled.…

  19. Study of the Effectiveness and Efficiency of Charter Schools in Indiana

    ERIC Educational Resources Information Center

    Akey, Terri; Plucker, Jonathan A.; Hansen, John A.; Michael, Robert; Branon, Suzanne; Fagen, Rebecca; Zhou, Gary

    2008-01-01

    In July of 2007, the Center for Evaluation and Education Policy (CEEP) at Indiana University was contracted to conduct an evaluation of the Indiana charter schools. The evaluation has been designed to ensure that all objectives of the provisions of HEA 1001-2007 are fulfilled. In addition, the framework of the study is based in IC 20-24-2-1,…

  20. Analyzing Task-Based User Study Data to Determine Colormap Efficiency

    SciTech Connect

    Ashton, Zoe Charon Maria; Wendelberger, Joanne Roth; Ticknor, Lawrence O.; Turton, Terece; Samsel, Francesca

    2015-07-23

    Domain scientists use colormaps to visualize their data. These are useful for identifying areas of interest including Eddy Identification and Characterizing Currents. New colormaps have been designed by visual artist Francesca Samsel. User studies have been implemented to determine whether or not these colormaps are an improvement.