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Sample records for radiotracer efficiency study

  1. UV-photochemical vapor generation of selenium for atomic absorption spectrometry: Optimization and 75Se radiotracer efficiency study

    NASA Astrophysics Data System (ADS)

    Rybínová, Marcela; Musil, Stanislav; Červený, Václav; Vobecký, Miloslav; Rychlovský, Petr

    2016-09-01

    Volatile selenium compounds were generated UV-photochemically in the continuous flow mode using four UV-photoreactors differing in the material of the reaction coil; Teflon tubing and quartz tubes with various inner diameters and wall thicknesses were tested. Atomic absorption spectrometry with an externally heated quartz furnace atomizer was employed as the detector. The relevant experimental generation parameters were optimized and the basic analytical characteristics were determined. Using formic acid as the photochemical agent, limits of detection achieved for selenium were in the range 46-102 ng L- 1 in dependence on the type of UV-photoreactor employed. When nitric acid was also added to the photochemical agent, the limits of detection were reduced to 27-44 ng L- 1. The repeatability did not exceed 2.4% (5 μg L- 1 Se(IV), n = 10). Experiments with 75Se radiotracer have been performed for the first time to quantify the efficiency of UV-photochemical vapor generation (UV-PVG) of selenium. The highest efficiency of 67 ± 1% was obtained for a UV-photoreactor containing a quartz reaction coil (2.0 mm i.d., 4.0 mm o.d.). The generation efficiency of 61 ± 1% was obtained for a Teflon reaction coil (1.0 mm i.d., 1.4 mm o.d.). Mapping of the radiotracer distribution in the individual parts of the apparatus did not reveal substantial transport losses of the analyte in the UV-PVG system.

  2. Monoamine oxidase: radiotracer chemistry and human studies.

    PubMed

    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 serotonin, 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 years since the first radiotracers were developed and the first positron emission tomography (PET) images of MAO in humans were carried out, PET studies of brain MAO in healthy volunteers and in patients have identified different variables that 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 the following: (1) the development of MAO radiotracers; (2) human studies including the relationship of brain MAO levels to genotype, personality, neurological, and psychiatric disorders; and (3) examples of the use of MAO radiotracers in drug research and development. We will conclude with outstanding needs to improve the radiotracers that are currently used and possible new applications.

  3. 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

  4. 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.

  5. 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.

  6. Radiotracer Dilution Method for Mercury Inventory Study in Electrolytic Cells

    SciTech Connect

    Sugiharto; Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Santoso, Sigit Budi; Abidin, Zainal; Santoso, Gatot Budi

    2010-06-22

    Purpose of the experiment is to demonstrate feasibility the use of radiotracer to measure weight of mercury in electrolytic cells of soda industry. The weight of mercury in each cell of the plant is designed approximately 1700 kg. Radiotracer is prepared by mixing {sup 203}Hg radioactive mercury with 2400 g of inactive mercury in a bath. The respective precisely weighted mercury aliquots to be injected into the cells are prepared by pouring approximately 130 g of radioactive mercury taken from the bath into 13 standard vials, in accordance with the number of the cells tested. Four standard references prepared by further dilution of {+-}2 g active mercury taken from the bath to obtain the dilution factors range of 12,000 to 20,000 from which the calibration graph is constructed. The injection process is conducting by pouring the radioactive mercury from aliquots into the flowing mercury at the inlet side of the cell and allows them to mix thoroughly. It is assumed that the mass of the radiotracer injected into a closed system remains constant, at least during the period of the test. From this experiment it was observed that the mixing time is two days after injection of radioactive mercury. The inactive mercury in each electrolytic cell calculated by the radiotracer method is of the range 1351.529 kg to 1966.354 kg with maximum error (95% confidence) is 1.52 %. The accuracy of measurement of the present method is better than gravimetric one which accounts 4 % of error on average.

  7. 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.

  8. Radiotracer studies on ion-selective membranes based on poly(vinyl chloride) matrices.

    PubMed

    Jaber, A M; Moody, G J; Thomas, J D; Willcox, A

    1977-10-01

    Radiotracer studies with (45)Ca, (89)Sr and (133)Ba have provided evidence that the permeation of magnesium, strontium and barium ions through PVC membranes containing Orion 92-20-02 liquid ion-exchanger is inhibited by their low affinity for the liquid ion-exchanger sites. Experiments with (7)Be indicate a strong affinity of the membrane for beryllium ions with corresponding inhibition of permeation. When acid is present in the solution on one side of the membrane, preferential permeation by protons may lead to transport of ions against their concentration gradient in order to maintain the balance of charge.

  9. Anaerobic degradation of naphthalene in a fluvial aquifer: a radiotracer study.

    PubMed

    Bianchin, Mario; Smith, Leslie; Barker, James F; Beckie, Roger

    2006-03-20

    A radiotracer study was conducted in a creosote-contaminated aquifer beneath the Fraser River, British Columbia Canada to investigate the in situ degradation of naphthalene. The groundwater is anaerobic, with abundant methane, ferrous iron and carbon dioxide. This study followed earlier work at the site where the contaminant distribution could only be explained by invoking a mass loss through degradation, even though extensive field and laboratory microcosm studies closer to the source zone onshore could not confirm degradation. Accordingly, 14C-naphthalene was injected into the aquifer offshore, further from the source zone where modeling suggested degradation was occurring. During the 230-day monitoring period, 14CO2 was detected, confirming the degradation of the radio-labeled naphthalene tracer. A zero-order degradation rate of naphthalene of 5 microg/L-day was estimated based on the decrease in 14C-naphthalene concentration with time. While the degradation pathway could not be determined from the radiotracer study alone, the geochemistry of the site suggests that either iron reduction or methanogenesis is the terminal electron accepting processes responsible for naphthalene oxidation. PMID:16487624

  10. Radiotracer studies on calcium ion-selective electrode membranes based on poly(vinyl chloride) matrices.

    PubMed

    Craggs, A; Moody, G J; Thomas, J D; Willcox, A

    Radiotracer studies with (45)Ca and (36)Cl demonstrate that PVC matrix membranes containing Orion 92-20-02 liquid calcium ion-exchanger are permselective to counter-cations. Diffusion coefficients are quoted for the migration of (45)Ca between pairs of calcium solutions and are discussed in terms of solution concentration, membrane thickness and concentration level of sensor in the membrane. Migration of calcium ions from calcium chloride solution to a Group (II) metal chloride solution through a PVC membrane containing calcium liquid ion-exchanger is discussed in terms of solvent extraction and electrode selectivity coefficient parameters. Thus, magnesium, strontium and barium ions appear to inhibit migration through the membrane by their low affinity for the membrane liquid ion-exchanger sites, while the inhibition by beryllium ions is attributed to site blockage by the strong affinity of dialkylphosphate sites for beryllium.

  11. 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.

  12. PET studies of binding competition between endogenous dopamine and the D1 radiotracer [11C]NNC 756.

    PubMed

    Abi-Dargham, A; Simpson, N; Kegeles, L; Parsey, R; Hwang, D R; Anjilvel, S; Zea-Ponce, Y; Lombardo, I; Van Heertum, R; Mann, J J; Foged, C; Halldin, C; Laruelle, M

    1999-05-01

    NNC 756 ((+)-8-chloro-5-(2,3-dihydrobenzofuran-7-yl)-7-hydroxy-3-methyl-2,3,4,5- tetrahydro-1H-3-benzazepine) is a new high affinity dopamine (DA) D1 receptor antagonist. Labeled with C-11, it has been used as a PET radiotracer to visualize D1 receptors both in striatal and extrastriatal areas, such as the prefrontal cortex. The goal of this study was to evaluate several methods for derivation of D1 receptor binding potential (BP) with [11C]NNC 756 in baboons, and to use these methods to assess the vulnerability of [11C]NNC 756 binding to competition by endogenous DA. A three-compartment model provided a good fit to PET data acquired following a single bolus injection. BP values obtained with this analysis were in good agreement with values derived from in vitro studies. BP values measured following injection of the potent DA releaser amphetamine (1 mg/kg, n=2) were similar to values measured under control conditions. Kinetic parameters derived from single bolus experiments were used to design a bolus plus continuous infusion administration protocol aimed at achieving a state of sustained binding equilibrium. Injection of amphetamine during sustained equilibrium did not affect [11C]NNC 756 binding. Similar results were observed with another D1 radiotracer, [11C]SCH 23390. Doses of amphetamine used in this study are known to reduce by 20-40% the binding potential of several D2 receptors radiotracers. Therefore, the absence of displacement of [11C]NNC 756 by an endogenous DA surge may indicate important differences between D1 and D2 receptors in vivo, such as differences in proportion of high affinity states not occupied by DA at baseline. These findings may also imply that a simple binding competition model is inadequate to account for the effects of manipulation of endogenous DA levels on the in vivo binding of radiolabeled antagonists.

  13. A philosophy for CNS radiotracer design.

    PubMed

    Van de Bittner, Genevieve C; Ricq, Emily L; Hooker, Jacob M

    2014-10-21

    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.

  14. Radiotracer method for residence time distribution study in multiphase flow system.

    PubMed

    Sugiharto, S; Su'ud, Z; Kurniadi, R; Wibisono, W; Abidin, Z

    2009-01-01

    [(131)I] isotope in different chemical compounds have been injected into 24in hydrocarbon transmission pipeline containing approximately 95% water, 3% crude oil, 2% gas and negligible solid material, respectively. The system is operated at the temperature around 70 degrees C enabling fluids flow is easier in the pipeline. The segment of measurement was chosen far from the junction point of the pipeline, therefore, it was reasonably to assume that the fluids in such multiphase system were separated distinctively. Expandable tubing of injector was used to ensure that the isotopes were injected at the proper place in the sense that [(131)I]Na isotope was injected into water layer and iodo-benzene, ([131])IC(6)H(5,) was injected into crude oil regime. The radiotracer selection was based on the compatibility of radiotracer with each of fluids under investigation. [(131)I]Na was used for measuring flow of water while iodo-benzene, ([131])IC(6)H(5,) was used for measuring flow of crude oil. Two scintillation detectors were used and they are put at the distances 80 and 100m, respectively, from injection point. The residence time distribution data were utilized for calculation water and crude oil flows. Several injections were conducted in the experiments. Although the crude oil density is lighter than the density of water, the result of measurement shows that the water flow is faster than the crude oil flow. As the system is water-dominated, water may act as carrier and the movement of crude oil is slowed due to friction between crude oil with water and crude oil with gas at top layer. Above of all, this result was able to give answer on the question why crude oil always arrives behind water as it is checked at gathering station. In addition, the flow patterns of the water in the pipeline calculated by Reynolds number and predicted by simple tank-in-series model is turbulence in character.

  15. 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

  16. Novel methodology for the study of mercury methylation and reduction in sediments and water using 197Hg radiotracer.

    PubMed

    Ribeiro Guevara, Sergio; Zizek, Suzana; Repinc, Urska; Pérez Catán, Soledad; Jaćimović, Radojko; Horvat, Milena

    2007-03-01

    Mercury tracers are powerful tools that can be used to study mercury transformations in environmental systems, particularly mercury methylation, demethylation and reduction in sediments and water. However, mercury transformation studies using tracers can be subject to error, especially when used to assess methylation potential. The organic mercury extracted can be as low as 0.01% of the endogenous labeled mercury, and artefacts and contamination present during methylmercury (MeHg) extraction processes can cause interference. Solvent extraction methods based on the use of either KBr/H2SO4 or HCl were evaluated in freshwater sediments using 197Hg radiotracer. Values obtained for the 197Hg tracer in the organic phase were up to 25-fold higher when HCl was used, which is due to the coextraction of 197Hg2+ into the organic phase during MeHg extraction. Evaluations of the production of MeHg gave similar results with both MeHg extraction procedures, but due to the higher Hg2+ contamination of the controls, the uncertainty in the determination was higher when HCl was used. The Hg2+ contamination of controls in the HCl extraction method showed a nonlinear correlation with the humic acid content of sediment pore water. Therefore, use of the KBr/H2SO4 method is recommended, since it is free from these interferences. 197Hg radiotracer (T1/2=2.673 d) has a production rate that is about 50 times higher than that of 203Hg (T1/2=46.595 d), the most frequently used mercury radiotracer. Hence it is possible to obtain a similar level of performance to 203Hg when it is used it in short-term experiments and produced by the irradiation of 196Hg with thermal neutrons, using mercury targets with the natural isotopic composition. However, if the 0.15% natural abundance of the 196Hg isotope is increased, the specific activity of the 197Hg tracer can be significantly improved. In the present work, 197Hg tracer was produced from mercury 51.58% enriched in the 196Hg isotope, and a 340-fold

  17. Synthesis and evaluation of inhaled [11C]butane and intravenously injected [11C]acetone as potential radiotracers for studying inhalant abuse.

    PubMed

    Gerasimov, Madina R; Ferrieri, Richard A; Pareto, Deborah; Logan, Jean; Alexoff, David; Ding, Yu-Shin

    2005-02-01

    The phenomenon of inhalant abuse is a growing problem in the US and many countries around the world. Yet, relatively little is known about the pharmacokinetic properties of inhalants that underlie their abuse potential. While the synthesis of 11C-labeled toluene, acetone and butane has been proposed in the literature, none of these compounds has been developed as radiotracers for PET studies. In the present report we extend our previous studies with [11C]toluene to include [11C]acetone and [11C]butane with the goal of comparing the pharmacokinetic profiles of these three volatile abused substances. Both [11C]toluene and [11C]acetone were administered intravenously and [11C]butane was administered via inhalation to anesthesized baboons. Rapid and efficient uptake of radiolabeled toluene and acetone into the brain was followed by fast clearance in the case of toluene and slower kinetics in the case of acetone. [11C]Butane was detected in the blood and brain following inhalation, but the levels of radioactivity in both tissues dropped to half of the maximal values over the period of less than a minute. To our knowledge, this is the first reported study of the in vivo brain pharmacokinetics of labeled acetone and butane in nonhuman primates. These data provide insight into the pharmacokinetic features possibly associated with the abuse liability of toluene, acetone and butane.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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)

  6. 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.

  7. 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.

  8. Studies on In-situ Chelation/Supercritical Fluid Extraction of Lanthanides and Actinides Using a Radiotracer Technique

    SciTech Connect

    Lin, Yuehe; Wu, Hong; Smart, Neil G.; Wai, Chien M.

    2001-06-01

    Radioisotope tracer techniques were used to study the process of in-situ chelation/supercritical fluid extraction(SFE) of La3+ and Lu3+ from solid matrix using mixed ligand hexafluoroacetylacetone (HFA) and tributylphosphate (TBP) as chelating agents. A lab-built SFE extactor was used in this study and the extractor design was optimized based on the experimental results. Quantitative recovery of La and Lu was achieved when the extrator design was optimized. Extraction of uranium from real world samples was also investigated to demonstrate the capability of this chelation/SFE technology for environmental remediation applications. A novel on-line back extraction technique for the recovery of metal ions and regeneration of ligands is also reported.

  9. The use of [18F]4-fluorobenzyl iodide (FBI) in PET radiotracer synthesis: model alkylation studies and its application in the design of dopamine D1 and D2 receptor-based imaging agents.

    PubMed

    Mach, R H; Elder, S T; Morton, T E; Nowak, P A; Evora, P H; Scripko, J G; Luedtke, R R; Unsworth, C D; Filtz, T; Rao, A V

    1993-08-01

    [18F]4-Fluorobenzyl iodide ([18F]FBI) was prepared, and a series of model alkylation studies were conducted to determine its chemical reactivity toward nitrogen and sulfur nucleophiles of varying nucleophilicities. [18F]FBI was found to react rapidly with secondary amines and anilines to give the corresponding N-[18F]4-fluorobenzyl analogue in high yield. Amides and thiol groups required the use of a base catalyst. The utility of [18F]FBI was documented by investigation of dopamine D1 and D2 receptor-based radiotracers.

  10. "High specific activity" radiotracers for metallo-toxicological studies: cyclotron and nuclear reactor production, radiochemical separation and "quality control": platinum, iridium, gold, copper and gallium.

    PubMed

    Bonardi, Mauro; Groppi, Flavia; Birattari, Claudio; Arginelli, Dolores

    2002-09-01

    Very High Specific Activity RadioNuclides, HSARN, are a powerful tool to label a wide variety of chemical elements and compounds present in the biosphere in ultra-trace amounts. Medium and high Z radionuclides, can be produced by irradiation in light-ions accelerator and sometimes nuclear reactor. If the nuclear reaction product has atomic number different from irradiated target, it is possible separating the radioactive nuclide from irradiated target, without addition of isotopic carrier. These kinds of radionuclides are named No Carrier Added, NCA, and their specific activity is very high and can reach values close to the theoretical Carrier Free one. The true specific activity must be determined by use of very sensitive radioanalytical techniques. If a low isotopic dilution factor is obtained, these radiotracers are used to label inorganic species and complexes of elements, which are presently introduced into the echo-systems by human activities. New production methods for NCA Pt, Ir, Au, Cu and Ga radiotracers are presented, with some details on radiochemistry and quality controls.

  11. 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.

  12. 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.

  13. 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

  14. Spatially resolved micro-X-ray fluorescence and micro-X-ray absorption fine structure study of a fractured granite bore core following a radiotracer experiment

    NASA Astrophysics Data System (ADS)

    Denecke, Melissa A.; Brendebach, Boris; De Nolf, Wout; Falkenberg, Gerald; Janssens, Koen; Simon, Rolf

    2009-08-01

    Spatially resolved X-ray absorption and fluorescence investigation with a micrometer-scale resolution on actinide-containing samples provide information necessary for safety assessment of nuclear waste disposal. In this paper one example of such an experiment is presented. This example entails neptunium speciation in a fractured granite bore core from the Swedish Äspö Hard Rock Laboratory following a radiotracer experiment using µ-XAFS and µ-XRF. In order to probe micro-volumes below the surface in the granite samples and thereby avoid potential changes in the Np speciation during cutting of the bore core, a confocal irradiation-detection geometry is employed. µ-XAFS results for a selected granite bore core cross section with ~ 3 nmol Np/g reveal that Np, originally introduced as Np(V) in the tracer cocktail, is present in the granite in its reduced Np(IV) form. The Np(IV) is often present as particles, tens of µm in size. Elemental distribution maps show the tracer Np to be located in fissures and permeable channels not larger than 100 µm. The Np distribution appears often correlated with Zn also present in some fissures. We observe small granite fissures containing Fe (presumably Fe(II)), where we do not detect any Np. It is feasible that inflowing Np(V) has a shorter residence time in large fractures, while in the smaller fissures migration is slower, leading to longer residence times, i.e., reaction times, where it is reduced to less soluble Np(IV) and becomes thereby immobilized.

  15. 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

  16. 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

  17. A fluoro versus a nitro derivative-a high-performance liquid chromatography study of two basic analytes with different reversed phases and silica phases as basis for the separation of a positron emission tomography radiotracer.

    PubMed

    Wenzel, Barbara; Günther, Robert; Brust, Peter; Steinbach, Jörg

    2013-10-11

    To develop a basis for the separation of a (18)F-labeled PET radiotracer from its nitro precursor, we performed an analytical HPLC study using the unlabeled reference compound and the corresponding nitro precursor. Aim of the study was to find a separation in which the fluoro derivative elutes in front of the nitro precursor with appropriate separation parameters. Several RP phases as well as a bare silica column were investigated with ACN and MeOH as organic modifiers and aqueous NH4OAc because of the basic character of the analytes. Four types of separation were observed based on different interaction mechanisms. When ACN/20mM NH4OAc aq. was used mainly cationic-exchange and hydrophobic interactions contributed to the retention. A reversal of elution order could be observed starting from 95% ACN and subsequent increasing of the water content. This phenomenon was observed for all RP phases and seems to be independent of the different spacers bound to the silica. By contrast, using MeOH/20mM NH4OAc aq. the elution order depends on the phase material. Two columns with the potential to perform π-π interactions showed different separation behavior compared to the other RP phases.

  18. Design, evaluation, and comparison of ghrelin receptor agonists and inverse agonists as suitable radiotracers for PET imaging.

    PubMed

    Chollet, Constance; Bergmann, Ralf; Pietzsch, Jens; Beck-Sickinger, Annette G

    2012-04-18

    Ghrelin agonist and inverse agonist radiotracers, suitable for positron emission tomography (PET), were developed to study the behavior of ghrelin receptor ligands in vivo and for further design of druggable peptides. The target peptides were synthesized on solid support and conjugated to the bifunctional chelator 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA), which is known to form a stable complex with Ga(3+). Complexation with (68)Ga could be achieved under mild conditions and led to radiotracers with high radiochemical purity and specific activity. The biological activity of the radiotracers was evaluated in vitro by an inositol phosphate turnover assay. Pharmacokinetic profile and metabolic stability of the (68)Ga-NODAGA-radiotracers were investigated by small animal PET in rodent. Ghrelin derived agonists presented very high kidney accumulation, negligible tissue distribution, fast blood clearance, and poor stability in blood. Contrarily, the inverse agonist radiotracer exhibited very high stability in blood, large diffusion in tissues, reasonable kidney and liver metabolism, and slow blood clearance. This pharmacokinetic profile makes the ghrelin inverse agonist motif KwFwLL-CONH(2) suitable for further development of radiotracers and a promising lead to design peptide-based therapeutics against obesity. PMID:22372770

  19. Further evaluation of [11C]MP-10 as a radiotracer for phosphodiesterase 10A (PDE10A): PET imaging study in rhesus monkeys and brain tissue metabolite analysis

    PubMed Central

    Lin, Shu-fei; Labaree, David; Chen, Ming-Kai; Holden, Daniel; Gallezot, Jean-Dominique; Kapinos, Michael; Teng, Jo-Ku; Najafzadeh, Soheila; Plisson, Christophe; Rabiner, Eugenii A.; Gunn, Roger N.; Carson, Richard E.; Huang, Yiyun

    2014-01-01

    [11C]MP-10 is a potent and specific PET tracer previously shown to be suitable for imaging the PDE10A in baboons with reversible kinetics and high specific binding. However, another report indicated that [11C]MP-10 displayed seemingly irreversible kinetics in rhesus monkeys, potentially due to the presence of a radiolabeled metabolite capable of penetrating the blood-brain-barrier (BBB) into the brain. This study was designed to address the discrepancies between the species by re-evaluating [11C]MP-10 in vivo in rhesus monkey with baseline scans to assess tissue uptake kinetics and self-blocking scans with unlabeled MP-10 to determine binding specificity. Ex vivo studies with one rhesus monkey and 4 Sprague-Dawley rats were also performed to investigate the presence of radiolabeled metabolites in the brain. Our results indicated that [11C]MP-10 displayed reversible uptake kinetics in rhesus monkeys, albeit slower than in baboons. Administration of unlabeled MP-10 reduced the binding of [11C]MP-10 in a dose-dependent manner in all brain regions including the cerebellum. Consequently, the cerebellum appeared not to be a suitable reference tissue in rhesus monkeys. Regional volume of distribution (VT) was mostly reliably derived with the multilinear analysis (MA1) method. In ex vivo studies in the monkey and rats only negligible (< 2.7%) amount of radiometabolites was seen in the brain of either species. In summary, results from the present study strongly support the suitability of [11C]MP-10 as a radiotracer for PET imaging and quantification of PDE10A in non-human primates. PMID:25450608

  20. 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

  1. 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

  2. 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

  3. Radiotracers for low density lipoprotein biodistribution studies in vivo: technetium-99m low density lipoprotein versus radioiodinated low density lipoprotein preparations

    SciTech Connect

    Vallabhajosula, S.; Paidi, M.; Badimon, J.J.; Le, N.A.; Goldsmith, S.J.; Fuster, V.; Ginsberg, H.N.

    1988-07-01

    In an attempt to characterize the in vivo behavior of (99mTc) low density lipoprotein (LDL), biodistribution studies were performed in normal and hypercholesterolemic (HC) rabbits. In normal rabbits, 24 hr after the injection of (99mTc)LDL, 99mTc activity accumulated mainly in adrenal glands, spleen, liver, and kidney. In HC rabbits, however, there was a marked reduction of 99mTc activity in these organs. In both normal and HC rabbits, less than 17% of 99mTc activity appeared in the 24-hr urine following injection of (99mTc)LDL, suggesting that in vivo, (99mTc)LDL is trapped and accumulated within the tissues. Direct comparison of (99mTc)LDL, 125I-native-LDL and (131I)tyramine cellobiose-LDL (the previously validated trapped radioligand) in normal rabbits, demonstrated that the biodistribution of (99mTc)LDL was similar to that of (131I)tyramine cellobiose-LDL. The adrenal glands, liver, and spleen accumulated significantly greater quantities of 99mTc and 131I activity per gram of tissue than 125I (from native-LDL). In addition, imaging studies in monkeys, showed that the hepatic uptake and retention of (99mTc) LDL was similar to that of (131I)tyramine cellobiose LDL. In contrast, radioiodine from native-LDL was deiodinated in liver with subsequent excretion into the intestine. These results suggest that (99mTc)LDL acts as a trapped ligand in vivo and should therefore, be a good tracer for noninvasive quantitative biodistribution studies of LDL.

  4. Radiotracers for low density lipoprotein biodistribution studies in vivo: technetium-99m low density lipoprotein versus radioiodinated low density lipoprotein preparations.

    PubMed

    Vallabhajosula, S; Paidi, M; Badimon, J J; Le, N A; Goldsmith, S J; Fuster, V; Ginsberg, H N

    1988-07-01

    In an attempt to characterize the in vivo behavior of [99mTc] low density lipoprotein (LDL), biodistribution studies were performed in normal and hypercholesterolemic (HC) rabbits. In normal rabbits, 24 hr after the injection of [99mTc]LDL, 99mTc activity accumulated mainly in adrenal glands, spleen, liver, and kidney. In HC rabbits, however, there was a marked reduction of 99mTc activity in these organs. In both normal and HC rabbits, less than 17% of 99mTc activity appeared in the 24-hr urine following injection of [99mTc]LDL, suggesting that in vivo, [99mTc]LDL is trapped and accumulated within the tissues. Direct comparison of [99mTc]LDL, 125I-native-LDL and [131I]tyramine cellobiose-LDL (the previously validated trapped radioligand) in normal rabbits, demonstrated that the biodistribution of [99mTc]LDL was similar to that of [131I]tyramine cellobiose-LDL. The adrenal glands, liver, and spleen accumulated significantly greater quantities of 99mTc and 131I activity per gram of tissue than 125I (from native-LDL). In addition, imaging studies in monkeys, showed that the hepatic uptake and retention of [99mTc] LDL was similar to that of [131I]tyramine cellobiose LDL. In contrast, radioiodine from native-LDL was deiodinated in liver with subsequent excretion into the intestine. These results suggest that [99mTc]LDL acts as a trapped ligand in vivo and should therefore, be a good tracer for noninvasive quantitative biodistribution studies of LDL.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. 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

  10. [(64)Cu]diacetyl-bis(N(4)-methyl-thiosemicarbazone) - a radiotracer for tumor hypoxia.

    PubMed

    Wood, Katie A; Wong, Wai Lup; Saunders, Michele I

    2008-05-01

    Positron emission tomography scanning using the radiotracer-labeled copper (II)-diacetyl-bis(N(4)-methylthiosemicarbazone) has been proposed as a noninvasive method for evaluating tumor hypoxia. Tumor hypoxia results in a more aggressive tumor phenotype together with resistance to both radiotherapy and chemotherapy. A noninvasive technique for evaluation of tumor hypoxia is not currently available. Validation of this technique would provide clinicians with a tool for determining the most appropriate cancer therapy, prognostic information, and subvolume delineation for the radiotherapy dose escalation to the radioresistant hypoxic regions within a tumor. This review article describes the background to the development of this tracer, its proposed retention mechanism, biodistribution dosimetry and the preclinical and clinical studies to date. It outlines the potential use of this radiotracer for imaging in the field of oncology.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. Cross-coupling reactions as valuable tool for the preparation of PET radiotracers.

    PubMed

    Pretze, Marc; Grosse-Gehling, Philipp; Mamat, Constantin

    2011-01-26

    The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of new radiotracers and novel radiolabeling procedures with the most prominent short-lived positron emitters carbon-11 and fluorine-18. Radiolabeling with these radionuclides represents a remarkable challenge. Special attention has to be paid to synthesis time and specific labeling techniques due to the short physical half life of the respective radionuclides ¹¹C (t(½) = 20.4 min) and ¹⁸F (t½) = 109.8 min). In the past, numerous transition metal-catalyzed reactions were employed in organic chemistry, even though only a handful of these coupling reactions were adopted in radiochemical practice. Thus, the implementation of modern synthesis methods like cross-coupling reactions offers the possibility to develop a wide variety of novel radiotracers. The introduction of catalysts based on transition metal complexes bears a high potential for rapid, efficient, highly selective and functional group-tolerating incorporation of carbon-11 and fluorine-18 into target molecules. This review deals with design, application and improvement of transition metal-mediated carbon-carbon as well as carbon-heteroatom cross-coupling reactions as a labeling feature with the focus on the preparation of radiolabeled compounds for molecular imaging.

  17. 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.

  18. 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.

  19. Radiotracer investigation in an industrial-scale oxidizer.

    PubMed

    Pant, H J; Sharma, V K

    2015-05-01

    A radiotracer investigation was carried out in an industrial-scale oxidizer. The main objectives of the investigation were to measure residence time distribution (RTD) of organic process fluid, determine the mean residence time (MRT) and investigate the degree of axial mixing. Bromine-82 as p-dibromo biphenyl was used as a radiotracer for measuring RTD of the organic process fluid. The MRT of the fluid in the oxidizer was determined to be 390min. An ideal stirred tank model with a plug flow reactor in recirculation stream was used to simulate the measured RTD data and was found suitable for describing flow in the system. Based on the model simulation the mean residence times in oxidizer and recycle stream were estimated. The results of the investigation showed that the oxidizer behaved as a well-mixed reactor whereas the recycle stream behaved as a plug flow reactor. PMID:25766114

  20. 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

  1. Radionuclides, radiotracers and radiopharmaceuticals for in vivo diagnosis

    NASA Astrophysics Data System (ADS)

    Wiebe, Leonard I.

    Radioactive tracers for in vivo clinical diagnosis fall within a narrow, strictly-defined set of specifications in respect of their physical properties, chemical and biochemical characteristics, and (approved) medical applications. The type of radioactive decay and physical half-life of the radionuclide are immutable properties which, along with the demands of production and supply, limit the choice of radionuclides used in medicine to only a small fraction of those known to exist. In use, the biochemical and physiological properties of a radiotracer are dictated by the chemical form of the radionuclide. This chemical form may range from elemental, molecular or ionic, to complex compounds formed by coordinate or covalent bonding of the radionuclide to either simple organic or inorganic molecules, or complex macromolecules. Few of the radiotracers which are tested in model systems ever become radiopharmaceuticals in the strictest sense. Radionuclides, radiotracers and radiopharmaceuticals in use are reviewed. Drug legislation and regulations concerning drug manufacture, as well as hospital ethical constraints and legislation concerning unsealed sources of radiation must all be satisfied in order to translate a radiopharmaceutical from the laboratory to clinical use.

  2. Potential therapeutic radiotracers: preparation, biodistribution and metabolic characteristics of 177Lu-labeled cyclic RGDfK dimer.

    PubMed

    Shi, Jiyun; Liu, Zhaofei; Jia, Bing; Yu, Zilin; Zhao, Huiyun; Wang, Fan

    2010-06-01

    In this study, we reported the preparation and evaluation of (177)Lu-DOTA-RGD2, (177)Lu-DOTA-Bz-RGD2 and (177)Lu-DTPA-Bz-RGD2 (RGD2 = E[c(RGDfK)](2)) as a potential therapeutic radiotracers for the treatment of integrin alpha(v)beta(3)-positive tumors. The BALB/c nude mice bearing the U87MG human glioma xenografts were used to evaluate the biodistribution characteristics and excretion kinetics of (177)Lu-DOTA-RGD2, (177)Lu-DOTA-Bz-RGD2 and (177)Lu-DTPA-Bz-RGD2. It was found that there were no major differences in their lipophilicity and biodistribution characteristics, particularly at latter time points. A major advantage of using DTPA-Bz as the bifunctional chelator (BFC) was its high radiolabeling efficiency (fast and high yield radiolabeling) at room temperature. Using DOTA and DOTA-Bz as BFCs, the radiolabeling kinetics was slow, and heating at 100 degrees C and higher DOTA-conjugate concentration were needed for successful (177)Lu-labeling. Therefore, DTPA-Bz is an optimal BFC for routine preparation of (177)Lu-labeled cyclic RGDfK peptides, and (177)Lu-DTPA-Bz-RGD2 is worthy of further investigation for targeted radiotherapy of integrin alpha(v)beta(3)-positive tumors.

  3. 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

  4. 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.

  5. Development of gamma-emitting, receptor binding radiotracers for imaging the brain and pancreas

    SciTech Connect

    Reba, R.C.

    1990-01-01

    This progress report covers period from Nov. 1, 1989 to Aug. 31, 1990. The long term objective was to develop receptor-binding radiotracers for SPECT or PET imaging of CNS or peripheral nervous system. The specific chemistry aims, as understood on the basis of past findings, were: to synthesize and develop a more polar analogs of 4IQNB, possessing similar binding characteristics but eliminated more rapidly from the surrounding tissues and the target organ, to design a method of introducing a technetium chelating group onto a molecule or cholinergic agent without drastic lowering of its apparent affinity, to synthesize and develop radiotracers based on m-AChR antagonists selective for one of the subtypes of the receptor. The chemistry service aims were to prepare and characterize (R,R)- and (R,S)-4IQNB and derivatives, to provide the triazene intermediate to other investigators, and to provide ({sup 123}I)4IQNB for in vivo imaging. The biochemistry aims were to characterize the vitro and in vivo properties of novel compounds and to perform the pharmacokinetic studies. 3 refs., 5 tabs.

  6. Designing steriod receptor-based radiotracers to image breast and prostate tumors

    SciTech Connect

    Katzenellenbogen, J.A.

    1995-06-01

    Imaging of breast or prostate cancers based on their content of steroid receptors poses a major challenge in the design of radiotracers. Receptors for steroid hormones are proteins that interact at specific sites in chromatin. Several analogs of estrogens, progestins and androgens have been radiolabeled and evaluated both in vitro and in vivo for receptor binding affinity and selectivity. Breast tumors in patients have been imaged with [{sup 18}F]fluoroestradiol. Scintigraphic images with radiolabeled progestin analogs may be useful for monitoring the efficacy of tamoxifen treatment in breast cancer patients. Tissue distribution and imaging studies in animals with fluorine-substituted androgens indicate that it may be possible to develop a steroid receptor-based radiotracer for staging prostate cancer. Radiochemists are reporting some progress in labeling steroid receptor ligands with {sup 99m}Tc. By using the techniques of molecular nuclear medicine, new imaging procedures could be developed that might provide more precise information to help characterize disease and effect treatment decisions in patients with breast or prostate cancers. 55 refs., 4 figs., 4 tabs.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. PET-Specific Parameters and Radiotracers in Theoretical Tumour Modelling

    PubMed Central

    Marcu, Loredana G.; Bezak, Eva

    2015-01-01

    The innovation of computational techniques serves as an important step toward optimized, patient-specific management of cancer. In particular, in silico simulation of tumour growth and treatment response may eventually yield accurate information on disease progression, enhance the quality of cancer treatment, and explain why certain therapies are effective where others are not. In silico modelling is demonstrated to considerably benefit from information obtainable with PET and PET/CT. In particular, models have successfully integrated tumour glucose metabolism, cell proliferation, and cell oxygenation from multiple tracers in order to simulate tumour behaviour. With the development of novel radiotracers to image additional tumour phenomena, such as pH and gene expression, the value of PET and PET/CT data for use in tumour models will continue to grow. In this work, the use of PET and PET/CT information in in silico tumour models is reviewed. The various parameters that can be obtained using PET and PET/CT are detailed, as well as the radiotracers that may be used for this purpose, their utility, and limitations. The biophysical measures used to quantify PET and PET/CT data are also described. Finally, a list of in silico models that incorporate PET and/or PET/CT data is provided and reviewed. PMID:25788973

  13. Energy-efficient electric motors study

    SciTech Connect

    Not Available

    1981-03-23

    The study identifies the industrial decision makers, investigated the information they needed to know, how they can best be reached, and the motivating factors for purchasing energy-efficient electric motors. A survey was conducted of purchasers of integral horsepower polyphase motors. The survey measured current knowledge of and awareness of energy-efficient motors, decision-making criteria, information sources, purchase and usage patterns, and related factors. The survey data 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. A description of study findings, conclusions, and recommendations is presented. Sample questionnaires and copies of letters to respondents are presented in 3 appendices. Appendices D and E contain descriptions of the methods used. (MCW)

  14. The [18F]2-Fluoro-1,3-thiazolyl Moiety - an Easily-Accessible Structural Motif for Prospective Molecular Imaging Radiotracers

    PubMed Central

    Siméon, Fabrice G.; Wendahl, Matthew T.; Pike, Victor W.

    2010-01-01

    2-Fluoro-1,3-thiazoles were rapidly and efficiently labeled with no-carrier-added fluorine-18 (t1/2 = 109.7 min) by treatment of readily prepared 2-halo precursors with cyclotron-produced [18F]fluoride ion. The [18F]2-fluoro-1,3-thiazolyl moiety constitutes a new and easily-labeled structural motif for prospective molecular imaging radiotracers. PMID:21057601

  15. 64Cu-labeled lissamine rhodamine B: a promising PET radiotracer targeting tumor mitochondria.

    PubMed

    Zhou, Yang; Kim, Young-Seung; Yan, Xin; Jacobson, Orit; Chen, Xiaoyuan; Liu, Shuang

    2011-08-01

    Enhanced mitochondrial potential in carcinoma cells is an important characteristic of cancer. It is of great current interest to develop a radiotracer that is sensitive to mitochondrial potential changes at the early stage of tumor growth. In this report, we present the synthesis and evaluation of (64)Cu-labeled Lissamine rhodamine B (LRB), (64)Cu(DOTA-LRB) (DOTA-LRB = 2-(6-(diethylamino)-3-(diethyliminio)-3H-xanthen-9-yl)-5-(N-(2-(2-(4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclo-dodecan-1-yl)acetamido)ethyl)sulfamoyl)benzenesulfonate) as a new radiotracer for imaging tumors in athymic nude mice bearing U87MG human glioma xenografts by positron emission tomography (PET). We also explored its localization mechanism using Cu(DOTA-LRB) as the fluorescent probe in both the U87MG human glioma cell line and the cultured primary U87MG glioma cells. It was found that (64)Cu(DOTA-LRB) had the highest tumor uptake (6.54 ± 1.50, 6.91 ± 1.26, 5.68 ± 1.13, 7.58 ± 1.96, and 5.14 ± 1.50%ID/g at 0.5, 1, 2, 4, and 24 h postinjection, respectively) among many (64)Cu-labeled organic cations evaluated in the same animal model. The cellular staining study indicated that Cu(DOTA-LRB) was able to localize in mitochondria of U87MG glioma cells due to the enhanced negative mitochondrial potential. This statement is completely supported by the results from decoupling experiment with carbonylcyanide-m-chlorophenylhydrazone (CCCP). MicroPET data showed that the U87MG glioma tumors were clearly visualized as early as 30 min postinjection with (64)Cu(DOTA-LRB). (64)Cu(DOTA-LRB) remained stable during renal excretion, but underwent extensive degradation during hepatobiliary excretion. On the basis of the results from this study, it was concluded that (64)Cu(DOTA-LRB) represents a new class of promising PET radiotracers for noninvasive imaging of the MDR-negative tumors.

  16. 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.

  17. 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.

  18. Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

    PubMed Central

    Schiper, Luis; Faintuch, Bluma Linkowski; da Silva Badaró, Roberto José; de Oliveira, Erica Aparecida; Chavez, Victor E. Arana; Chinen, Elisangela; Faintuch, Joel

    2016-01-01

    OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT) and histological analysis. RESULTS: Radiolabeling achieved high (>95%) radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC)-E-[c(RGDfK)2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP), but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK)2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1) Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2) Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK)2. 3) These techniques appear promising and warrant further studies to determine their potential clinical applications. PMID

  19. OpenPET: A Flexible Electronics System for Radiotracer Imaging.

    PubMed

    Moses, W W; Buckley, S; Vu, C; Peng, Q; Pavlov, N; Choong, W-S; Wu, J; Jackson, C

    2009-10-24

    We present the design for OpenPET, an electronics readout system designed for prototype radiotracer imaging instruments. The critical requirements are that it has sufficient performance, channel count, channel density, and power consumption to service a complete camera, and yet be simple, flexible, and customizable enough to be used with almost any detector or camera design. An important feature of this system is that each analog input is processed independently. Each input can be configured to accept signals of either polarity as well as either differential or ground referenced signals. Each signal is digitized by a continuously sampled ADC, which is processed by an FPGA to extract pulse height information. A leading edge discriminator creates a timing edge that is "time stamped" by a TDC implemented inside the FPGA. This digital information from each channel is sent to an FPGA that services 16 analog channels, and information from multiple channels is processed by this FPGA to perform logic for crystal lookup, DOI calculation, calibration, etc. As all of this processing is controlled by firmware and software, it can be modified / customized easily. The system is open source, meaning that all technical data (specifications, schematics and board layout files, source code, and instructions) will be publicly available.

  20. OpenPET: A Flexible Electronics System for Radiotracer Imaging

    PubMed Central

    Moses, W. W.; Buckley, S.; Vu, C.; Peng, Q.; Pavlov, N.; Choong, W.-S.; Wu, J.; Jackson, C.

    2011-01-01

    We present the design for OpenPET, an electronics readout system designed for prototype radiotracer imaging instruments. The critical requirements are that it has sufficient performance, channel count, channel density, and power consumption to service a complete camera, and yet be simple, flexible, and customizable enough to be used with almost any detector or camera design. An important feature of this system is that each analog input is processed independently. Each input can be configured to accept signals of either polarity as well as either differential or ground referenced signals. Each signal is digitized by a continuously sampled ADC, which is processed by an FPGA to extract pulse height information. A leading edge discriminator creates a timing edge that is “time stamped” by a TDC implemented inside the FPGA. This digital information from each channel is sent to an FPGA that services 16 analog channels, and information from multiple channels is processed by this FPGA to perform logic for crystal lookup, DOI calculation, calibration, etc. As all of this processing is controlled by firmware and software, it can be modified / customized easily. The system is open source, meaning that all technical data (specifications, schematics and board layout files, source code, and instructions) will be publicly available. PMID:21297894

  1. Physician efficiency and reimbursement: a case study.

    PubMed

    Cantrell, L E; Flick, J A

    1986-01-01

    Joint ventures between hospitals and doctors are being widely developed and reported as the most promising mechanism for building alliances, providing financial rewards, and accessing new markets. However, joint ventures cannot be structured to involve an entire medical staff directly. Likewise, they cannot motivate a medical staff to change medical practice patterns in order to improve a hospital's reimbursement efficiency. This article describes a system of physician economic efficiency criteria that is being used by one hospital in making medical staff reappointment decisions and has the effect of placing all physicians at risk individually for the hospital's reimbursement performance. Although somewhat controversial, this economic efficiency program has proven a remarkably effective tool for change.

  2. Evaluation of 64Cu-labeled acridinium cation: a PET radiotracer targeting tumor mitochondria.

    PubMed

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

    2011-04-20

    This report presents the synthesis and evaluation of (64)Cu(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 (64)Cu(DO3A-xy-ACR) was excreted mainly through the renal system with >65% of injected radioactivity being recovered from urine samples at 1 h postinjection (p.i.). The tumor uptake of (64)Cu(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. (64)Cu(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 (64)Cu(DO3A-xy-ACR). The high liver radioactivity accumulation was also seen. (64)Cu(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 (64)Cu(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 (64)Cu(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 (64)Cu-labeled acridinium cations are indeed able to localize in the energized mitochondria of tumor cells.

  3. 64Cu-labeled phosphonium cations as PET radiotracers for tumor imaging.

    PubMed

    Zhou, Yang; Liu, Shuang

    2011-08-17

    Alteration in mitochondrial transmembrane potential (ΔΨ(m)) is an important characteristic of cancer. The observation that the enhanced negative mitochondrial potential is prevalent in tumor cell phenotype provides a conceptual basis for development of mitochondrion-targeting therapeutic drugs and molecular imaging probes. Since plasma and mitochondrial potentials are negative, many delocalized organic cations, such as rhodamine-123 and (3)H-tetraphenylphosphonium, are electrophoretically driven through these membranes, and able to localize in the energized mitochondria of tumor cells. Cationic radiotracers, such as (99m)Tc-Sestamibi and (99m)Tc-Tetrofosmin, have been clinically used for diagnosis of cancer by single photon emission computed tomography (SPECT) and noninvasive monitoring of the multidrug resistance (MDR) transport function in tumors of different origin. However, their diagnostic and prognostic values are often limited due to their insufficient tumor localization (low radiotracer tumor uptake) and high radioactivity accumulation in the chest and abdominal regions (low tumor selectivity). In contrast, the (64)Cu-labeled phosphonium cations represent a new class of PET (positron emission tomography) radiotracers with good tumor uptake and high tumor selectivity. This review article will focus on our recent experiences in evaluation of (64)Cu-labeled phosphonium cations as potential PET radiotracers. The main objective is to illustrate the impact of radiometal chelate on physical, chemical, and biological properties of (64)Cu radiotracers. It will also discuss some important issues related to their tumor selectivity and possible tumor localization mechanism.

  4. 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.

  5. 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.

  6. 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

  7. Cyclotron production and potential clinical application of Iodine-124 labeled radiotracers

    NASA Astrophysics Data System (ADS)

    Finn, R.; Balatoni, J.; Kothari, P.; Pentlow, K.; Sheh, Y.; Lom, C.; Dahl, J.; Eckelman, W.; Plascjak, P.; Adams, H. R.; Larson, S. M.

    2001-07-01

    Positron emission tomography (PET) is a dynamic molecular imaging technique applicable to clinical research, drug development as well as clinical diagnoses. The potential for PET is derived from specificity of the radiotracers and radioligands that are synthesized to monitor the biochemical or physiological processes. Further developments will depend on an increasing availability of unique radiotracers. Iodine-124, a radionuclide that has potential for both diagnostic and therapeutic applications, possesses a half-life of 4.18 days and decays by positron emission (23.3%) and electron capture (76.7%). The preparation of this radionuclide via the 124Te(p,n)124I nuclear reaction is described as well as chemistry associated with the preparation of specific radiotracers and radiopharmaceuticals incorporating iodine-124 at Memorial Sloan-Kettering Cancer Center.

  8. 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.

  9. Indepth diagnosis of a secondary clarifier by the application of radiotracer technique and numerical modeling.

    PubMed

    Kim, H S; Shin, M S; Jang, D S; Jung, S H

    2006-01-01

    To make an indepth diagnosis of a full-scale rectangular secondary clarifier, an experimental and numerical study has been performed in a wastewater treatment facility. Calculation results by the numerical model with the adoption of the SIMPLE algorithm of Patankar are validated with radiotracer experiments. Emphasis is given to the prediction of residence time distribution (RTD) curves. The predicted RTD profiles are in good agreement with the experimental RTD curves at the upstream and center sections except for the withdrawal zone of the complex effluent weir structure. The simulation results predict successfully the well-known flow characteristics of each stage such as the waterfall phenomenon at the front of the clarifier, the bottom density current and the surface return flow in the settling zone, and the upward flow in the exit zone. The detailed effects of density current are thoroughly investigated in terms of high SS loading and temperature difference between influent and ambient fluid. The program developed in this study shows the high potential to assist in the design and determination of optimal operating conditions to improve effluent quality in a full-scale secondary clarifier.

  10. 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.

  11. Distributed microprocessor automation network for synthesizing radiotracers used in positron emission tomography

    SciTech Connect

    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. 20 refs. (DT)

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. [(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

  19. Increasing the accuracy of radiotracer monitoring in one-dimensional flow using polynomial deconvolution correction.

    PubMed

    Peyvandi, Reza Gholipour; Taheri, Ali

    2016-01-01

    Factors such as type of fluid movement and gamma-ray scattering may decrease the precision of the radiotracer monitoring as the response to a short tracer injection. Practical experiences using polynomial deconvolution techniques are presented. These techniques were successfully applied for correcting the obtained experimental results and increasing the time resolution of the method. PMID:26609682

  20. 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.

  1. 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.

  2. Isatin sulfonamides: potent caspases-3 and -7 inhibitors, and promising PET and SPECT radiotracers for apoptosis imaging.

    PubMed

    Limpachayaporn, Panupun; Schäfers, Michael; Haufe, Günter

    2015-01-01

    Caspases-3 and -7 play an essential role in apoptosis. Isatin sulfonamides have been identified as potent inhibitors of these executing caspases. Besides pharmacological application, these compounds can also serve as recognition units to target caspases using positron emission tomography (PET) and single-photon emission computed tomography (SPECT) when labeled with a positron or a gamma emitter. Fluorinated, alkylated, arylated isatin derivatives, in addition to derivatives modified with heterocycles, have been prepared in order to improve their binding potency, selectivity and metabolic stability. Structural optimization has led to stable, highly active inhibitors, which after labeling have been applied in PET studies in tumor mouse models and for first preclinical and clinical investigations with healthy human volunteers. The results support further development of such radiotracers for clinical apoptosis imaging. PMID:26132525

  3. 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.

  4. Coeur d'Alene Tribe Energy Efficiency Feasibility Study

    SciTech Connect

    Allgood, Tiffany L.; Sorter, Andy

    2014-09-01

    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.

  5. Practice efficiency and physician compensation: a case study.

    PubMed

    Shaw, D V

    2002-01-01

    One of the major challenges facing today's health care executive is that of achieving maximum efficiency. The public also requires an efficient health care system. However, a problem occurs when the health care executive defines "efficiency" in a manner that is diametrically opposed to the public's definition. Maximum efficiency in the physician practice is defined by productivity equal to capacity. Maximum efficiency of the health care system is defined by lower health care costs. If the physician practice is achieving its goal of maximum efficiency, the market economy will likely force a failure in achieving the public's goal of a lower cost health care system! The following case study provides an opportunity to review this health care management conundrum and offers insights into a possible approach for some solution through attention to physician compensation. PMID:12534255

  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. Biological evaluation of new [(18) F]F-labeled synthetic amino acid derivatives as oncologic radiotracers.

    PubMed

    Kim, Yeseulmi; Lee, Sang Ju; Yook, Cheol-Min; Oh, Seung Jun; Ryu, Jin-Sook; Lee, Jong Jin

    2016-08-01

    The present study evaluated the tumoral uptake of the novel synthetic amino acid positron emission tomography (PET) tracers (S)-2-amino-3-(4-([(18) F]fluoromethyl)-1H-1,2,3-triazol-1-yl)propanoic acid (AMC-101), (S)-2-amino-4-(4-([(18) F]fluoromethyl)-1H-1,2,3-triazol-1-yl)butanoic acid (AMC-102), and (S)-2-amino-5-(4-([(18) F]fluoromethyl)-1H-1,2,3-triazol-1-yl)pentanoic acid (AMC-103), all of which are (S)-2-amino-(4-([(18) F]fluoromethyl)-1H-1,2,3-triazol-1-yl)alkyl acids. In vitro cellular uptake was investigated using the rat glioma cell lines 9L and C6. In vitro competitive inhibition tests were performed to identify the involvement of specific amino acid transporters. In vivo dynamic PET images of 9L xenograft tumor-bearing model mice were acquired over 2 h after AMC administration. [(18) F]FDOPA PET studies were performed with and without S-carbidopa pretreatment for comparison. All three AMCs exhibited good in vitro cell uptake through the L and alanine-serine-cysteine transporters and enabled clear tumor visualization on PET, leaving the brain devoid of the tracer. Thirty minutes after injection, the mean tumor standardized uptake values were 1.59 ± 0.05, 1.89 ± 0.27, and 1.74 ± 0.13 for AMC-101, AMC-102, and AMC-103, respectively. Although the tumor uptake values of AMCs were lower than that of [(18) F]FDOPA with S-carbidopa pretreatment, AMCs enabled higher contrast images with lower background activity compared with [(18) F]FDOPA with S-carbidopa pretreatment. Our results indicate the potential uses of these new synthetic amino acids as oncologic radiotracers.

  8. 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.

  9. 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.

  10. Pre-clinical characterization of [11C]R05013853 as a novel radiotracer for imaging of the glycine transporter type 1 by positron emission tomography.

    PubMed

    Borroni, Edilio; Zhou, Yun; Ostrowitzki, Susanne; Alberati, Daniela; Kumar, Anil; Hainzl, Dominik; Hartung, Thomas; Hilton, John; Dannals, Robert F; Wong, Dean F

    2013-07-15

    A specific positron emission tomography (PET) radiotracer for the glycine transporter type 1 (GlyT1) would constitute an imaging biomarker to investigate the distribution of GlyT1 in normal individuals and those with neuropsychiatric disorders. In addition it could demonstrate the ability of a novel drug to reach its target in the brain and enable receptor occupancy studies, thus facilitating drug development. In this article we describe the evaluation in non-human primates of two candidate PET radiotracers ([(11)C]RO5013852 and [(11)C]RO5013853) previously characterized in the rat. Both radiotracers showed acceptable uptake in the baboon brain and heterogeneous distribution consistent with that reported for GlyT1. In vivo blockade studies with two specific glycine reuptake inhibitors (GRIs), RO5013853 and bitopertin (RG1678, reduced uptake of both tracers to homogenous levels across brain regions and demonstrated specificity of the signal. [(11)C]RO5013853 showed a larger specific signal and slightly higher brain uptake and was therefore selected for further characterization. Quantitative compartmental analysis of PET data showed that the 2-tissue compartment model with 5 parameters was the most appropriate to describe the kinetics of [(11)C]RO5013853. Two additional methods were used: a) the Logan graphical analysis using plasma input and, b) a linear parametric imaging approach with the 2-tissue compartmental model. These produced VT estimates of comparable magnitude, namely, pons, thalamus and cerebellum>caudate, putamen and cortical regions. High resolution autoradiography with tritiated RO5013853 was used to confirm the binding pattern observed by PET. In vivo metabolism studies in the baboon demonstrated the formation of a single, radiolabeled metabolite more polar than the parent compound. Finally, [(11)C]RO5013853 was used to quantify the degree of cerebral GlyT1 occupancy observed in the baboon following oral administration of bitopertin, a selective GRI

  11. 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.

  12. 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. )

  13. (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

  14. 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

  15. 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.

  16. 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

  17. Environmental biochemistry of current environmental levels of heavy metals: preparation of radiotracers with very high specific radioactivity for metallobiochemical experiments on laboratory animals.

    PubMed

    Sabbioni, E; Goetz, L; Birattari, C; Bonardi, M

    1981-03-01

    Environmental toxicology research on dose-response relationships of heavy metals requires experiments on laboratory animals exposed to "low doses" of trace elements which should reflect "present or actual environmental levels" characteristic of polluted environments. Unfortunately no criteria exist to establish the "low doses" to which laboratory animals must be exposed, in practice the choice of the level used is made in an almost arbitrary manner. In order to define the "present environmental levels" of heavy metals which should be administered to laboratory animals an approach is suggested, based upon knowledge of the concentrations of trace elements in the diet, air and food as well as the fractions absorbed. Today daily intakes of trace elements by man are of the order of few micrograms or nanograms thus requiring the use of extremely sensitive analytical techniques to determine the very low amounts of heavy metals in tissues and cellular components. In these fields of research the use of radiotracers with very high specific radioactivity appears particularly advantageous but requires considerable care during their preparation and use. The first part of this paper deals with a definition of the ranges of concentrations of trace elements which should be used for metabolic studies on laboratory animals when they are exposed via different routes such as ingestion, inhalation in injection; the second part describes the production of radiotracers with very high specific radioactivity by proton activation in the cyclotron and by neutron irradiation in the nuclear reactor. Their use to label present levels of heavy metals under conditions adapted for biochemical purposes, as well as the preparation of different metal-labelled chemical species is also reported. Particular attention is directed to quality control of the radiotracer solutions which are administered to the animals including those of radioactivity concentrations, radioisotopic purity, radiochemical purity

  18. In Vivo Metabolic Trapping Radiotracers for Imaging Monoamine Oxidase-A and -B Enzymatic Activity.

    PubMed

    Brooks, Allen F; Shao, Xia; Quesada, Carole A; Sherman, Phillip; Scott, Peter J H; Kilbourn, Michael R

    2015-12-16

    The isozymes of monoamine oxidase (MAO-A and MAO-B) are important enzymes involved in the metabolism of numerous biogenic amines, including the neurotransmitters serotonin, dopamine, and norepinephrine. Recently, changes in concentrations of MAO-B have been proposed to be an in vivo marker of neuroinflammation associated with Alzheimer's disease. Previous developments of in vivo radiotracers for imaging changes in MAO enzyme expression or activity have utilized the irreversible propargylamine-based suicide inhibitors or high-affinity reversibly binding inhibitors. As an alternative approach, we have investigated 1-[(11)C]methyl-4-aryloxy-1,2,3,6-tetrahydropyridines as metabolic trapping agents for the monoamine oxidases. MAO-mediated oxidation and spontaneous hydrolysis yield 1-[(11)C]methyl-2,3-dihydro-4-pyridinone as a hydrophilic metabolite that is trapped within brain tissues. Radiotracers with phenyl, biphenyl, and 7-coumarinyl ethers were evaluated using microPET imaging in rat and primate brains. No isozyme selectivity for radiotracer trapping was observed in the rat brain for any compound, but in the monkey brain, the phenyl ether demonstrated MAO-A selectivity and the coumarinyl ether showed MAO-B selectivity. These are lead compounds for further development of 1-[(11)C]methyl-4-aryloxy-1,2,3,6-tetrahydropyridines with optimized brain pharmacokinetics and isozyme selectivity.

  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. 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

  1. Preclinical radiation dosimetry for the novel SV2A radiotracer [18F]UCB-H

    PubMed Central

    2013-01-01

    Background [18F]UCB-H was developed as a novel radiotracer with a high affinity for synaptic vesicle protein 2A, the binding site for the antiepileptic levetiracetam. The objectives of this study were to evaluate the radiation dosimetry of [18F]UCB-H in a preclinical trial and to determine the maximum injectable dose according to guidelines for human biomedical research. The radiation dosimetry was derived by organ harvesting and dynamic micro positron emission tomography (PET) imaging in mice, and the results of both methods were compared. Methods Twenty-four male C57BL-6 mice were injected with 6.96 ± 0.81 MBq of [18F]UCB-H, and the biodistribution was determined by organ harvesting at 2, 5, 10, 30, 60, and 120 min (n = 4 for each time point). Dynamic microPET imaging was performed on five male C57BL-6 mice after the injection of 9.19 ± 3.40 MBq of [18F]UCB-H. A theoretical dynamic bladder model was applied to simulate urinary excretion. Human radiation dose estimates were derived from animal data using the International Commission on Radiological Protection 103 tissue weighting factors. Results Based on organ harvesting, the urinary bladder wall, liver and brain received the highest radiation dose with a resulting effective dose of 1.88E-02 mSv/MBq. Based on dynamic imaging an effective dose of 1.86E-02 mSv/MBq was calculated, with the urinary bladder wall and liver (brain was not in the imaging field of view) receiving the highest radiation. Conclusions This first preclinical dosimetry study of [18F]UCB-H showed that the tracer meets the standard criteria for radiation exposure in clinical studies. The dose-limiting organ based on US Food and Drug Administration (FDA) and European guidelines was the urinary bladder wall for FDA and the effective dose for Europe with a maximum injectable single dose of approximately 325 MBq was calculated. Although microPET imaging showed significant deviations from organ harvesting, the Pearson’s correlation coefficient

  2. Implementation of maximin efficient designs in dose-finding studies.

    PubMed

    Fackle-Fornius, Ellinor; Miller, Frank; Nyquist, Hans

    2015-01-01

    This paper considers the maximin approach for designing clinical studies. A maximin efficient design maximizes the smallest efficiency when compared with a standard design, as the parameters vary in a specified subset of the parameter space. To specify this subset of parameters in a real situation, a four-step procedure using elicitation based on expert opinions is proposed. Further, we describe why and how we extend the initially chosen subset of parameters to a much larger set in our procedure. By this procedure, the maximin approach becomes feasible for dose-finding studies. Maximin efficient designs have shown to be numerically difficult to construct. However, a new algorithm, the H-algorithm, considerably simplifies the construction of these designs. We exemplify the maximin efficient approach by considering a sigmoid Emax model describing a dose-response relationship and compare inferential precision with that obtained when using a uniform design. The design obtained is shown to be at least 15% more efficient than the uniform design.

  3. 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…

  4. 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…

  5. 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.

  6. 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

  7. A 1-methyl-4-piperidinyl cytectrene carboxylate labeled by the technetium 99m, a radiotracer for rat brain acetylcholinesterase activity.

    PubMed

    Mejri, Najoua; Barhoumi, Chokri; Trabelsi, Moez; Mekni, Abdelkader; Said, Nadia Malek; Saidi, Mouldi

    2010-02-01

    Alzheimer's disease (AD) is a degenerative neurological disorder that causes progressive and irreversible loss of connections between brain cells and loss of mental functions. Clinical and postmortem studies show that the biochemical changes in brains of AD patients include decrease in acetylcholinesterase (AChE) activity. Our aim was to study AChE activity using piperidinyl ester labelled with technetium-99m. In vivo and in vitro studies demonstrated that labelled piperidinyl ester was a substrate for AChE. The hydrolytic rate of this substrate was measured and the specificity was evaluated using the inhibitor BW284c51. The rhenium analogues of the technetium-labelled substrate were used to determine the affinity constant (K(m)) and the maximum reaction velocity (V(max)) because of the high specific activity of technetium. The high hydrolytic rate and high specificity of the substrate for AChE make it suitable as an in vivo radiotracer for studying AChE activity in the brain.

  8. 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

  9. Investigation of hydrodynamic behaviour of membranes using radiotracer techniques

    NASA Astrophysics Data System (ADS)

    Miskiewicz, A.; Zakrzewska-Trznadel, G.

    2013-05-01

    The aim of the work was to study membrane devices using short-lived radioisotopes like Ba-137m and Ga-68 as tracers. These radioisotopes were obtained from radionuclide generators: Cs-137/Ba-137m and Ge-68/Ga-68. The first radionuclide, namely Ba-137m with a half-life of 2.55 minutes was applied as a liquid phase tracer for studying hydrodynamic conditions inside the membrane apparatus. The membrane module with ceramic membranes was tested by using Ba-137m. The experiments showed that this radionuclide with a short half-life is a perfect tracer for liquid phase, whereas Ga-68 with longer half-life equal to 68 minutes was considered as a solid phase (bentonite) tracer. Ga-68 was used to gain more knowledge about the phenomena occurring in the membrane boundary layer. After kinetic studies of isotope adsorption into the carrier material, the growth rate of the deposit layer as well as deposit's thickness on the flat-sheet membrane were studied. The influence of such process parameters like pressure, linear velocity of liquid and feed concentration on formation of the bentonite layer on the membrane surface was studied.

  10. 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.

  11. 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.

  12. 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.

  13. [(18)F]6-fluoro-3,4-dihydroxy-L-phenylalanine--recent modern syntheses for an elusive radiotracer.

    PubMed

    Edwards, Richard; Wirth, Thomas

    2015-05-15

    [(18)F]6-fluoro-3,4-dihydroxy-L-phenylalanine ([(18)F]F-DOPA) has been known to be a useful radiotracer for over 30 years. Its widespread clinical use has been hampered by the lack of a robust, high yielding synthesis. This review summarises new developments in radiochemistry that are providing solutions to long standing problems involved in the synthesis of this important but elusive radiotracer. Considerable advances in nucleophilic synthesis have been achieved by optimising multistep strategies and using both hypervalent iodine chemistry and transition metal-mediated fluorinations allowing for the production of high specific activity [(18)F]F-DOPA. PMID:25882075

  14. [(18)F]6-fluoro-3,4-dihydroxy-L-phenylalanine--recent modern syntheses for an elusive radiotracer.

    PubMed

    Edwards, Richard; Wirth, Thomas

    2015-05-15

    [(18)F]6-fluoro-3,4-dihydroxy-L-phenylalanine ([(18)F]F-DOPA) has been known to be a useful radiotracer for over 30 years. Its widespread clinical use has been hampered by the lack of a robust, high yielding synthesis. This review summarises new developments in radiochemistry that are providing solutions to long standing problems involved in the synthesis of this important but elusive radiotracer. Considerable advances in nucleophilic synthesis have been achieved by optimising multistep strategies and using both hypervalent iodine chemistry and transition metal-mediated fluorinations allowing for the production of high specific activity [(18)F]F-DOPA.

  15. 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

  16. 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.

  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. (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.

  19. 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.

  20. Comparative study of spray booth filter system efficiency.

    PubMed

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

    1999-03-01

    During recent years, greater emphasis has been placed on the control of particulate emissions from painting operations. This has gained more 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 PM10 emissions. In 1995, the U.S. Environmental Protection Agency 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 PM10 control capability of the various system designs. Paint overspray arrestor systems using five different filtration concepts or materials were selected. They include systems constructed of fiberglass, paper, Styrofoam, and cardboard materials. 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 PM10. This paper summarizes the results of the research conducted to determine the capability of the arrestor systems to capture particulate of sizes down to approximately 1 micron in surface diameter. PMID:10202455

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Metabolite identification of a radiotracer by electrochemistry coupled to liquid chromatography with mass spectrometric and radioactivity detection.

    PubMed

    Baumann, Anne; Faust, Andreas; Law, Marylin P; Kuhlmann, Michael T; Kopka, Klaus; Schäfers, Michael; Karst, Uwe

    2011-07-01

    Radioligands, which specifically bind to a receptor or enzyme (target), enable molecular imaging of the target expression by positron emission tomography (PET). One very promising PET tracer is (S)-1-(4-(2-[(18)F]-fluoroethoxy)benzyl)-5-[1-(2-methoxymethylpyrrolidinyl)sulfonyl]isatin (isatin), a caspase-3 inhibitor, which has been developed at the University Hospital of Münster to image cell death (apoptosis). The translation of this novel tracer from preclinical evaluation to clinical examinations requires biodistribution studies, which characterize the pharmakodynamics and metabolic fate of the compound. This information is used to further optimize the radioligands and to interpret radioactive signals from tissues upon injection of the radioligand in vivo with respect to their specificity. The analysis of the metabolism of radioligands is hampered by the low amount of the compound being typically injected (nano/picomolar amount per injection). In the present study, electrochemistry (EC) is applied to elucidate the oxidative metabolism pathway of the radiotracer. Previous studies have demonstrated that EC can be utilized as a complementary tool to conventional in vitro approaches in drug metabolism studies. Thereby, potential oxidative metabolites of the isatin are determined by EC coupled to electrospray ionization mass spectrometry (EC/ESI-MS). Moreover, using EC/liquid chromatography (LC) and ESI-ion trap MS(n), structural elucidation of the oxidation products is performed. Comparatively to EC, in vitro metabolism studies with rat liver microsomes are conducted. Finally, the developed LC/ESI-MS method is applied to determine metabolites in body fluids and cell extracts from in vivo studies with the nonradioactive ((19)F) and radioactive isatin ((18)F). On the basis of the electrochemically generated oxidation products of the radioligand, the major radioactive metabolite occurring in vivo was successfully identified.

  7. 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

  8. 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.

  9. H-CRRETAWAC-OH, a Lead Structure for the Development of Radiotracer Targeting Integrin α5β1?

    PubMed Central

    Maschauer, Simone; Einsiedel, Jürgen; Eder, Iris E.; Gmeiner, Peter; Virgolini, Irene J.

    2014-01-01

    Imaging of angiogenic processes is of great interest in preclinical research as well as in clinical settings. The most commonly addressed target structure for imaging angiogenesis is the integrin αvβ3. Here we describe the synthesis and evaluation of [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH, a radiolabelled peptide designed to selectively target the integrin α5β1. Conjugation of 4-nitrophenyl-(RS)-2-[18F]fluoropropionate provided [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH in high radiochemical purity (>95%) and a radiochemical yield of approx. 55%. In vitro evaluation showed α5β1 binding affinity in the nanomolar range, whereas affinity to αvβ3 and αIIbβ3 was >50 μM. Cell uptake studies using human melanoma M21 (αvβ3-positive andα5β1-negative), human melanoma M21-L (αvβ3-negative and α5β1-negative), and human prostate carcinoma DU145 (αvβ3-negative and α5β1-positive) confirmed receptor-specific binding. The radiotracer was stable in human serum and showed low protein binding. Biodistribution studies showed tumour uptake ranging from 2.5 to 3.5% ID/g between 30 and 120 min post-injection. However, blocking studies and studies using mice bearing α5β1-negative M21 tumours did not confirm receptor-specific uptake of [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH, although this radiopeptide revealed high affinity and substantial selectivity to α5β1 in vitro. Further experiments are needed to study the in vivo metabolism of this peptide and to develop improved radiopeptide candidates suitable for PET imaging of α5β1 expression in vivo. PMID:25374888

  10. 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.

  11. 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.

  12. 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.

  13. Federal energy efficiency and water conservation funding study

    SciTech Connect

    1998-01-01

    This report contains the results of a study required by section 162 of the Energy Policy Act of 1992 (EPAct). It outlines options for financing energy and water conservation measures at Federal facilities as required by Part 3 of Title V of the National Energy Policy and Conservation Act (NECPA) (42 U.S.C. 8251 et seq.) as amended by EPAct. It addresses: (1) the estimated Federal financial investment necessary to install energy and water conservation measures to meet NECPA and Executive Order requirements; (2) the use of revolving funds and other funding mechanisms which offer stable, long-term financing of energy and water conservation measures; and (3) the means for capitalizing such funds. On March 8, 1994, President Clinton signed Executive Order 12902. This Executive Order is an aggressive mandate to improve energy efficiency and water conservation in Federal buildings nationwide. This Executive Order is designed to meet and exceed requirements for Federal energy and water efficiency that were contained in section 152 of EPAct. Section 152 mandated that Federal agencies use all cost effective measures with less than a ten year payback to reduce energy consumption in their facilities by 20% by the year 2000 compared to 1985 levels. In addition, Executive Order 12902 established a requirement to use cost effective measures to reduce energy use by fiscal year 2005 by 30% compared to 1985 energy use. This report provides estimates for the energy and water conservation investments needed to achieve the NECPA and Executive Order goals as well as estimates for the contribution from various funding sources and a review of the mechanisms for funding these investments.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. Efficiency of thermography in the study of hydrological connectivity

    NASA Astrophysics Data System (ADS)

    Cantreul, Vincent; Burgeon, Victor; Triquet, Johan; Tuerlinck, Manon; Vaelen, Guillaume; Leemans, Vincent; Degré, Aurore

    2016-04-01

    Hydrologic connectivity is an emerging concept which permits deeper understanding of catchments behavior. However, the measurements of functional connectivity is complex and still needs new developments in order to approach the « dynamic » part of the story. This study aims at assessing the efficiency of thermography to analyze hydrologic connectivity in an agricultural catchment in Belgium (loamy soils). Tests have been performed on experimental tubs at first and on field at second. Under controlled conditions, hot milk was spread on an experimental tub with bare soil and grass. The hot milk permits to compare color tracer with thermic one. The results are quite good. The binarization of pictures from usual camera and from thermic one gives similar percentage of runoff coverage at same locations. The mean difference is about 8% for bare soils and 10% for planted grass. There is a slight overestimation with thermic camera because of time delay of soil cooling after milk passing. In the same time in the planted grass, there are some runoff pixels which are hidden by vegetation. On field, blue colored water was used to simulate a rainfall on a field covered with mustard and on the same field without any coverage. Where runoff flows, the soil appears warmer because of heat extracted by water in the soil. The results comparing visual and thermic pictures are more nuanced. The mean difference reaches 30% on bare soil. Indeed, (i) the rainfall drops seem to hide the runoff during the rain; (ii) the vegetation density (mustard) is quite a problem for runoff detection. However, the difference between successive time pictures permits to distinguish flow paths easily. In conclusion, thermography stands as a good alternative for connectivity study. It's obviously a preliminary study which gives some indications of the possible use of thermography. At present, we are testing real rainfalls (different types) with different camera's positions and different land use (different

  19. 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.

  20. 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

  1. Chewing efficiency and state of dentition. A methodologic study.

    PubMed

    Helkimo, E; Carlsson, G E; Helkimo, M

    1978-01-01

    Chewing efficiency, defined as the ability to grind a certain portion of a test food during a given time, was tested in 139 Skolt Lapps, ages 14-65. 94 persons had natural teeth and the remaining 45 wore dentures (partial and/or complete). The test food was almonds. Number of chewing strokes, swallowings and chewing time was denoted. The chewing efficiency was classified after a scale from 1 to 5 where 1 meant very good and 5 very poor ability to reduce the particle size of the test food. Clear associations were found between chewing efficiency and dental state. Number of occluding pairs of teeth was closely correlated with chewing efficiency and individuals with less than 20 teeth had a higher index score than those with more than 20 teeth. The values noted for number of chewing strokes, swallowings and chewing time were smaller for those with a good chewing efficiency, but the variation was not linear and not always significant. Denture wearers had statistically significantly higher chewing efficiency score than those with natural teeth, without dentures, and needed more chewing time before swallowing.

  2. 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

  3. 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.

  4. Analytical structural efficiency studies of borsic/aluminum compression panels

    NASA Technical Reports Server (NTRS)

    Mcwithey, R. R.

    1976-01-01

    Analytically determined mass-strength curves, strain-strength curves, and dimensions are presented for structurally efficient hat-stiffened panels, corrugation-stiffened panels, hat-stiffened honeycomb-core sandwich panels, open-section corrugation panels, and honeycomb-core sandwich panels. The panels were assumed to be fabricated from either titanium, borsic/aluminum, or a combination of these materials. Borsic/aluminum panels and titanium panels reinforced with borsic/aluminum were lighter and stiffer than comparably designed titanium panels. Reinforced titanium panels had the same extensional stiffness as comparably designed Borsic/aluminum panels. For a given load, the structural efficiency of the hat-stiffened honeycomb-core sandwich panel was higher than the structural efficiency of the other stiffened panels.

  5. 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.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Macro versus Microlab: A Controlled Study of Time Efficiency.

    ERIC Educational Resources Information Center

    Pickering, Miles; LaPrade, Joseph E.

    1986-01-01

    Describes a comparison of scale of laboratory with respect to time efficiency. Compared full scale and one-tenth scale Grignard reactions with full scale averaging 330 minutes to completion and scaled-down averaging 204. Savings are seen in air pollution, toxicity, solvent cost, and time. (JM)

  10. 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.

  11. PET and SPECT Radiotracers to Assess Function and Expression of ABC Transporters in Vivo

    PubMed Central

    Mairinger, Severin; Erker, Thomas; Müller, Markus; Langer, Oliver

    2013-01-01

    Adenosine triphosphate-binding cassette (ABC) transporters, such as P-glycoprotein (Pgp, ABCB1), breast cancer resistance protein (BCRP, ABCG2) and multidrug resistance-associated proteins (MRPs) are expressed in high concentrations at various physiological barriers (e.g. blood-brain barrier, blood-testis barrier, blood-tumor barrier), where they impede the tissue accumulation of various drugs by active efflux transport. Changes in ABC transporter expression and function are thought to be implicated in various diseases, such as cancer, epilepsy, Alzheimer’s and Parkinson’s disease. The availability of a non-invasive imaging method which allows for measuring ABC transporter function or expression in vivo would be of great clinical use in that it could facilitate the identification of those patients that would benefit from treatment with ABC transporter modulating drugs. To date three different kinds of imaging probes have been described to measure ABC transporters in vivo: i) radiolabelled transporter substrates ii) radiolabelled transporter inhibitors and iii) radiolabelled prodrugs which are enzymatically converted into transporter substrates in the organ of interest (e.g. brain). The design of new imaging probes to visualize efflux transporters is inter alia complicated by the overlapping substrate recognition pattern of different ABC transporter types. The present article will describe currently available ABC transporter radiotracers for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) and critically discuss strengths and limitations of individual probes and their potential clinical applications. PMID:21434859

  12. Whole lake addition of cadmium-109: radiotracer accumulation in the mussel population in the first season.

    PubMed

    Malley, D F; Chang, P S; Hesslein, R H

    1989-11-01

    Cadmium with the radiotracer 109Cd was added to the epilimnion of Precambrian Shield Lake 382 in the Experimental Lakes Area, northwestern Ontario to monitor pathways of Cd from water to abiotic and biotic components, to quantify Cd accumulation and distribution in biota and to evaluate adverse biological and ecological effects. This experiment will permit evaluation of the adequacy of the water quality guidelines of 0.2 microgram Cd l-1 in protecting aquatic life in softwater lakes. As part of the whole-lake experiment, we monitored the activities of 109Cd in various body parts of the floater mussel Anodonta grandis grandis to determine accumulation and distribution of Cd. Additions of Cd from 23 June to the end of October 1987 (a total of 900 g Cd and 89 mCi of 109Cd) increased the total [Cd] in the water from 1.6 to about 85 ng l-1. Cadmium-109 was accumulated in body parts of the mussels, in increasing concentration: mantle less than foot less than gill less than visceral mass less than kidney. After 4 months exposure to the increased water [Cd], the mussels had increased body burden of Cd by an estimated 5-9 times. At the latter increase, the population of 7330 +/- 2100 mussels in the lake contained an estimated 0.011-0.020% of the added 109Cd.

  13. Food chains and biogeochemical pathways: contributions of fallout and other radiotracers.

    PubMed

    Whicker, F Ward; Pinder, John E

    2002-05-01

    This paper reviews examples of how measurements of global fallout in the environment and related tracer radionuclides have been used to enhance our basic knowledge of biogeochemical processes and food-chain pathways. Because it is these fundamental, natural processes that control the transport and accumulation of such trace substances in the environment, direct measurements of trace substances over time and space reveal strong insights into these processes. The necessity to monitor global fallout transport, although largely motivated by human health concerns, gave rise to a plethora of new information about plants, animals, and natural and agricultural ecosystems and how they function. This review provides a small selection of examples in the areas of plant and animal physiology, productivity and energy transfer in food chains, biogeochemical cycles of certain elements and their analogues, feeding relationships and movements of organisms, and the agriculture-based human food chain. It is concluded that if society is to cope successfully with continued growth of the human population and resource consumption, more knowledge is still required about these fundamental processes. The use of radiotracers can contribute greatly to this need, but current funding priorities, societal attitudes, and onerous regulations on the use of radioactivity may continue to limit such applications.

  14. 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.

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

    PubMed

    Pérez Catán, Soledad; Guevara, Sergio Ribeiro; Marvin-DiPasquale, Mark; Magnavacca, Cecilia; Cohen, Isaac Marcos; Arribere, María

    2007-09-01

    Methodological considerations on the determination of benthic methyl-mercury (CH(3)Hg) production potentials were investigated on lake sediment, using (197)Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and gamma-irradiation. Flash freezing showed similar CH(3)Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with gamma-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 (197)Hg(II) carry-over in the organic extraction and/or [(197)Hg]CH(3)Hg produced via abiotic reactions. Two CH(3)Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO(4) 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.

  16. 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.

  17. Does microbial biomass affect pelagic ecosystem efficiency? An experimental study.

    PubMed

    Wehr, J D; Le, J; Campbell, L

    1994-01-01

    Bacteria and other microorganisms in the pelagic zone participate in the recycling of organic matter and nutrients within the water column. The microbial loop is thought to enhance ecosystem efficiency through rapid recycling and reduced sinking rates, thus reducing the loss of nutrients contained in organisms remaining within the photic zone. We conducted experiments with lake communities in 5400-liter mesocosms, and measured the flux of materials and nutrients out of the water column. A factorial design manipulated 8 nutrient treatments: 4 phosphorus levels × 2 nitrogen levels. Total sedimentation rates were greatest in high-N mesocosms; within N-surplus communities, [Symbol: see text]1 µM P resulted in 50% increase in total particulate losses. P additions without added N had small effects on nutrient losses from the photic zone; +2 µM P tanks received 334 mg P per tank, yet after 14 days lost only 69 mg more particulate-P than did control communities. Nutrient treatments resulted in marked differences in phytoplankton biomass (twofold N effect, fivefold P effect in +N mesocosms only), bacterioplankton densities (twofold N-effect, twofold P effects in -N and +N mesocosms), and the relative importance of autotrophic picoplankton (maximum in high NY mesocosms). Multiple regression analysis found that of 8 plankton and water chemistry variables, the ratio of autotrophic picoplankton to total phytoplankton (measured as chlorophyll α) explained the largest portion of the total variation in sedimentation loss rates (65% of P-flux, 57% of N-flux, 26% of total flux). In each case, systems with greater relative importance of autotrophic picoplankton had significantly reduced loss rates. In contrast, greater numbers of planktonic bacteria were associated with increased sedimentation rates and lower system efficiency. We suggest that different microbial components may have contrasting effects on the presumed enhanced efficiency provided by the microbial loop.

  18. Flow Structures and Efficiency of Swimming Fish school: Numerical Study

    NASA Astrophysics Data System (ADS)

    Yatagai, Yuzuru; Hattori, Yuji

    2013-11-01

    The flow structure and energy-saving mechanism in fish school is numerically investigated by using the volume penalization method. We calculate the various patterns of configuration of fishes and investigate the relation between spatial arrangement and the performance of fish. It is found that the down-stream fish gains a hydrodynamic advantage from the upstream wake shed by the upstream fish. The most efficient configuration is that the downstream fish is placed in the wake. It reduces the drag force of the downstream fish in comparison with that in solo swimming.

  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. [{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%.

  1. Study on High Efficient Electric Vehicle Wireless Charging System

    NASA Astrophysics Data System (ADS)

    Chen, H. X.; Liu, Z. Z.; Zeng, H.; Qu, X. D.; Hou, Y. J.

    2016-08-01

    Electric and unmanned is a new trend in the development of automobile, cable charging pile can not meet the demand of unmanned electric vehicle. Wireless charging system for electric vehicle has a high level of automation, which can be realized by unmanned operation, and the wireless charging technology has been paid more and more attention. This paper first analyses the differences in S-S (series-series) and S-P (series-parallel) type resonant wireless power supply system, combined with the load characteristics of electric vehicle, S-S type resonant structure was used in this system. This paper analyses the coupling coefficient of several common coil structure changes with the moving distance of Maxwell Ansys software, the performance of disc type coil structure is better. Then the simulation model is established by Simulink toolbox in Matlab, to analyse the power and efficiency characteristics of the whole system. Finally, the experiment platform is set up to verify the feasibility of the whole system and optimize the system. Based on the theoretical and simulation analysis, the higher charging efficiency is obtained by optimizing the magnetic coupling mechanism.

  2. 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.

  3. Discovery of a fluorinated 4-oxo-quinoline derivative as a potential positron emission tomography radiotracer for imaging cannabinoid receptor type 2.

    PubMed

    Slavik, Roger; Müller Herde, Adrienne; Haider, Ahmed; Krämer, Stefanie D; Weber, Markus; Schibli, Roger; Ametamey, Simon M; Mu, Linjing

    2016-09-01

    The cannabinoid receptor type 2 (CB2) is part of the endocannabinoid system and has gained growing attention in recent years because of its important role in neuroinflammatory/neurodegenerative diseases. Recently, we reported on a carbon-11 labeled 4-oxo-quinoline derivative, designated RS-016, as a promising radiotracer for imaging CB2 using PET. In this study, three novel fluorinated analogs of RS-016 were designed, synthesized, and pharmacologically evaluated. The results of our efforts led to the identification of N-(1-adamantyl)-1-(2-(2-fluoroethoxy)ethyl)-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxamide (RS-126) as the most potent candidate for evaluation as a CB2 PET ligand. [(18) F]RS-126 was obtained in ≥ 99% radiochemical purity with an average specific radioactivity of 98 GBq/μmol at the end of the radiosynthesis. [(18) F]RS-126 showed a logD7.4 value of 1.99 and is stable in vitro in rat and human plasma over 120 min, whereas 55% intact parent compound was found in vivo in rat blood plasma at 10 min post injection. In vitro autoradiographic studies with CB2-positive rat spleen tissue revealed high and blockable binding which was confirmed in in vivo displacement experiments with rats by dynamic PET imaging. Ex vivo biodistribution studies confirmed accumulation of [(18) F]RS-126 in rat spleen with a specificity of 79% under blocking conditions. The moderate elevated CB2 levels in LPS-treated mice brain did not permit the detection of CB2 by [(18) F]RS-126 using PET imaging. In summary, [(18) F]RS-126 demonstrated high specificity toward CB2 receptor in vitro and in vivo and is a promising radioligand for imaging CB2 receptor expression. Cannabinoid receptor type 2 (CB2) is an interesting target for PET imaging. Specific binding of [(18) F]RS-126 in CB2-positive spleen tissue (white arrow head) was confirmed in in vivo displacement experiments with rats. Time activity curve of [(18) F]RS-126 in the spleen after the addition of GW405833 (CB2

  4. [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

  5. 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

  6. 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.

  7. Problems of process-efficiency studies in psychotherapy.

    PubMed

    Meyer, A E

    1996-01-01

    Three areas of psychotherapy research can be delimited of which differential efficiency research promises to be the most fruitful, because it will eventually inform us which interventions with what kind of patient and what kind of problem will be the most constructive. One problem it can solve is the so-called equivalence paradox. This epitheton designates the fact, that in spite of the enormous differences in theory and interventions between the different kinds of psychotherapies, their results are not remarkably divergent. One quite popular hypothesis is that this is due to common factors, commun to any and every kind of psychotherapy. Our results indicate that this explanation is too simplistic because it uses a monosubstance-doses-effect-relationship model and disregards interaction. One other avenue is the relevant events approach. Our examples yield equivocal results. Nevertheless this remains a promising field of investigation. Finally there are time series analyses which are probably most germane to the field of psychotherapies. One illustration with a case of negative psychotherapy outcome is presented. Time series analysis is able to show that the patient changed to a negativistic attitude in the middle of session, whereas the psychoanalyst only changed at the beginning of session 10 respectively in its middle.

  8. 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

  9. Ionization efficiency studies for xenon ions with thesuperconducting ECR ion source VENUS

    SciTech Connect

    Leitner, Daniela; Lyneis, Claude M.; Todd, DamonS.; Tarvainen,Olli

    2007-06-05

    Ionization efficiency studies for high charge state xenon ions using a calibrated gas leak are presented. A 75% enriched {sup 129}Xe gas leak with a gas flow equivalent to 5.11p{mu}A was used in all the measurements. The experiments were performed at the VENUS (Versatile ECR ion source for Nuclear Science) ion source for 18 GHz, 28 GHz and double frequency operation. Overall, total ionization efficiencies close to 100% and ionization efficiencies into a single charge state up to 22% were measured. The influence of the biased disk on the ionization efficiency was studied and the results were somewhat surprising. When the biased disk was removed from the plasma chamber, the ionization efficiency was dramatically reduced for single frequency operation. However, using double frequency heating the ionization efficiencies achieved without the biased disk almost matched the ionization efficiencies achieved with the biased probe. In addition, we have studied the influence of the support gas on the charge state distribution of the xenon ions. Either pure oxygen or a mixture of oxygen and helium were used as support gases. The addition of a small amount of helium can increase the ionization efficiency into a single charge state by narrowing the charge state distribution. Furthermore by varying the helium flow the most efficient charge state can be shifted over a wide range without compromising the ionization efficiency. This is not possible using only oxygen as support gas. Results from these studies are presented and discussed.

  10. 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.

  11. 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.

  12. 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/.

  13. 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.

  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. 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.

  16. 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.

  17. 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

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

    PubMed Central

    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/68Ga-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 68Ga(CUR)2+, 68Ga(DAC)2+, and 68Ga(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/68Ga-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

  19. Synthesis, radioiodination and in vivo screening of novel potent iodinated and fluorinated radiotracers as melanoma imaging and therapeutic probes.

    PubMed

    Maisonial, Aurélie; Billaud, Emilie M F; Besse, Sophie; Rbah-Vidal, Latifa; Papon, Janine; Audin, Laurent; Bayle, Martine; Galmier, Marie-Josèphe; Tarrit, Sébastien; Borel, Michèle; Askienazy, Serge; Madelmont, Jean-Claude; Moins, Nicole; Auzeloux, Philippe; Miot-Noirault, Elisabeth; Chezal, Jean-Michel

    2013-05-01

    In order to develop new iodinated and fluorinated matched-pair radiotracers for Single-Photon Emission Computed Tomography (SPECT)/Positron Emission Tomography (PET) imaging and targeted radionuclide therapy of melanoma, we successfully synthesized and radiolabelled with iodine-125 seven new derivatives, starting from our previously described lead structure 3. The relevance of these radiotracers for gamma scintigraphic imaging of melanoma in rodent was assessed. The tumoural radioactivity uptake was most often high and specific even at early time points (12.1-18.3% ID/g at 3 h p.i. for [(125)I]39-42) and a fast clearance from the non-target organs was observed. Also, calculated effective doses that could be delivered to tumours when using corresponding [(131)I]-labelled analogues were generally higher than 100 cGy/MBq injected (98.9-150.5 cGy/MBq for [(131)I]39-42). These results make compounds 39-42 suitable candidates for (i) PET imaging of melanoma after labelling with fluorine-18 and (ii) targeted radionuclide therapy of disseminated melanoma after labelling with iodine-131.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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

  5. Study of Total Detection Efficiency (η) of Charge Exchange Analyzer (CXA) in TVD Tokamak

    NASA Astrophysics Data System (ADS)

    Kazemi, M.; Habibi, M.; Tafreshi, M.

    2013-02-01

    Diagnostic devices detection efficiency consist of many parameters. Contribution of each part in main detection efficiency need to study all aspect of devices and experimentally researches. In this paper experimental results and theoretical study merged to figure out the total detection efficiency of CXA. Most important primary parameters has been recognized (stripping foil thickness, incident energy, etc.) and effect of these parameters in related part studied. For CXA of TVD tokamak total detection efficiency presented and shown for 3 keV this parameter equal to .09 and stripping efficiency is equal 1.1 approximately. Choosing appropriate system for stripping of neutral beam is the most important factor in CXA diagnostic devices specially for high energy beams.

  6. 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…

  7. How efficient are Greek hospitals? A case study using a double bootstrap DEA approach.

    PubMed

    Kounetas, Kostas; Papathanassopoulos, Fotis

    2013-12-01

    The purpose of this study was to measure Greek hospital performance using different input-output combinations, and to identify the factors that influence their efficiency thus providing policy makers with valuable input for the decision-making process. Using a unique dataset, we estimated the productive efficiency of each hospital through a bootstrapped data envelopment analysis (DEA) approach. In a second stage, we explored, using a bootstrapped truncated regression, the impact of environmental factors on hospitals' technical and scale efficiency. Our results reveal that over 80% of the examined hospitals appear to have a technical efficiency lower than 0.8, while the majority appear to be scale efficient. Moreover, efficiency performance differed with inclusion of medical examinations as an additional variable. On the other hand, bed occupancy ratio appeared to affect both technical and scale efficiency in a rather interesting way, while the adoption of advanced medical equipment and the type of hospital improves scale and technical efficiency, correspondingly. The findings of this study on Greek hospitals' performance are not encouraging. Furthermore, our results raise questions regarding the number of hospitals that should operate, and which type of hospital is more efficient. Finally, the results indicate the role of medical equipment in performance, confirming its misallocation in healthcare expenditure.

  8. 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.

  9. 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

  10. Technology Efficiency Study on Nuclear Power and Coal Power in Guangdong Province Based on DEA

    SciTech Connect

    Yinong Li; Dong Wang

    2006-07-01

    Guangdong Province has taken the lead in embarking on nuclear power development to resolve its dire lack of primary resources. With the deepening of the on-going structural reform in the electric power sector in China, the market competition scheme is putting electricity generation enterprises under severe strain. Consequently, it is incumbent upon the nuclear power producers to steadily upgrade management, enhance technical capabilities, reduce cost and improve efficiency. At present, gradual application of such efficiency evaluation methodology has already commenced in some sectors in China including the electric power industry. The purpose of this paper is to use the Data Envelopment Analysis (DEA), which is a cutting-edge approach in the efficiency evaluation field - to study the technological efficiency between nuclear power and coal power in Guangdong Province. The DEA results demonstrate that, as far as Guangdong Province is concerned, the technological efficiency of nuclear power is higher than that of coal power in terms of Technological Efficiency (TE), Pure Technology Efficiency (PTE) and Scale Efficiency (SE). The reason is that nuclear power technology is advanced with a much higher equipment availability factor. Under the same scale, the generation output of nuclear power is far higher than that of equivalent coal power generation. With the environmental protection and sustainable development requirements taken into full account, nuclear power constitutes a clean, safe and highly-efficient energy form which should be extensively harnessed in Guangdong Province to fuel its future continuing economic growth. (authors)

  11. Study of the efficiency of immobilized algal technology for wastewater treatment.

    PubMed

    Kanherkar, S V; Late, A M; Nalawade, P M; Bhosaleanda, B J; Dhapate, S A

    2012-01-01

    The present paper deals with the study of efficiency of immobilized algal technology in wastewater treatment. The acclimatized algal species and wastewater samples were collected from three different sampling sites such as Kham River, Waluj [MIDC], Salim Ali Lake for the study. The encapsulation of collected algal species such as Spirogyra, Cyanobacteria in mixture form and Arthospira from selected sampling sites were made in sodium alginate for wastewater treatment. The percentage efficiency of immobilized algal technology for wastewater treatment was studied with respect to physico-chemical parameters. The physicochemical parameters were analyzed before and after treatment and compared for percentage efficiency study. The results obtained from present investigation reveal that the immobilized algal technology has maximum percentage efficiency in reduction of BOD, COD, Total Hardness, Total Alkalinity, Chloride. TSS, TDS and TSS. Whereas, the minimum fluctuations were found in pH and temperature. However, the immobilized algal technology is also useful to increase the dissolved oxygen concentration in wastewater treatment process.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. PET radiotracer [18F]-P6 selectively targeting COX-1 as a novel biomarker in ovarian cancer: Preliminary investigation

    PubMed Central

    Uddin, Jashim; Vitale, Paola; Panella, Andrea; Crews, Brenda C.; Daniel, Cristina K.; Ghebreselasie, Kebreab; Nickels, Mike; Tantawy, Mohammed N.; Manning, H. Charles; Marnett, Lawrence J.; Scilimati, Antonio

    2015-01-01

    Cyclooxygenase-1 (COX-1), but not COX-2, is expressed at high levels in the early stages of human epithelial ovarian cancer where it seems to play a key role in cancer onset and progression. As a consequence, COX-1 is an ideal biomarker for early ovarian cancer detection. A series of novel fluorinated COX-1-targeted imaging agents derived from P6 was developed by using a highly selective COX-1 inhibitor as a lead compound. Among these new compounds, designed by structural modification of P6, 3-(5-chlorofuran-2-yl)-5-(fluoromethyl)-4-phenylisoxazole ([18/19F]-P6) is the most promising derivative [IC50 = 2.0 μM (purified oCOX-1) and 1.37 μM (hOVCAR-3 cell COX-1)]. Its tosylate precursor was also prepared and, a method for radio[18F]chemistry was developed and optimized. The radiochemistry was carried out using a carrier-free K18F/Kryptofix 2.2.2 complex, that afforded [18F]-P6 in good radio-chemical yield (18%) and high purity (>95%). In vivo PET/CT imaging data showed that the radiotracer [18F]-P6 was selectively taken up by COX-1-expressing ovarian carcinoma (OVCAR 3) tumor xenografts as compared with the normal leg muscle. Our results suggest that [18F]-P6 might be an useful radiotracer in preclinical and clinical settings for in vivo PET-CT imaging of tissues that express elevated levels of COX-1. PMID:24832612

  17. 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

  18. 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…

  19. 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.

  20. 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…

  1. 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.

  2. 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.

  3. Parametric study of factors affecting the fuel efficiency of advanced turboprop airplanes

    NASA Technical Reports Server (NTRS)

    Johnson, V. S.

    1983-01-01

    Results of a parametric study to determine the effects of design variables and penalties on the fuel efficiency of Mach 0.8, 125-passenger, advanced turboprop airplanes show that propeller-wing interference penalty has a major effect. Propeller tip speed has a minor effect, and could be decreased to alleviate the noise problem without significant effects on fuel efficiency. The anticipated noise levels produced by the propfan will require additional acoustical treatment for the fuselage; this additional weight can have a significant effect on fuel efficiency. The propfan advantage over an equivalent technology turbofan is strongly dependent on the interference penalty and acoustical treatment weight. Lowering the cruise Mach number to around 0.73 would result in greatly increased fuel efficiency.

  4. Efficiency Study of NLS Base-Year Design. RTI-22U-884-3.

    ERIC Educational Resources Information Center

    Moore, R. P.; And Others

    An efficiency study was conducted of the base year design used for the National Longitudinal Study of the High School Class of 1972 (NLS). Finding the optimal design involved a search for the numbers of sample schools and students that would maximize the variance at a given cost. Twenty-one variables describing students' plans, attitudes,…

  5. 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…

  6. Validation of methodology for determination of the mercury methylation potential in sediments using radiotracers.

    PubMed

    Zizek, Suzana; Ribeiro Guevara, Sergio; Horvat, Milena

    2008-04-01

    Experiments to determine the mercury methylation potential were performed on sediments from two locations on the river Idrijca (Slovenia), differing in ambient mercury concentrations. The tracer used was the radioactive isotope (197)Hg. The benefit of using this tracer is its high specific activity, which enables spikes as low as 0.02 ng Hg(2+) g(-1) of sample to be used. It was therefore possible to compare the efficiency of the methylation potential experiments over a range of spike concentrations from picogram to microgram levels. The first part of the work aimed to validate the experimental blanks and the second part consisted of several series of incubation experiments on two different river sediments using a range of tracer additions. The results showed high variability in the obtained methylation potentials. Increasing Hg(2+) additions gave a decrease in the percentage of the tracer methylated during incubation; in absolute terms, the spikes that spanned four orders of magnitude (0.019-190 pg g(-1) of sediment slurry) resulted in MeHg formation between 0.01 and 0.1 ng MeHg g(-1) in Podroteja and Kozarska Grapa. Higher spikes resulted in slightly elevated MeHg production (up to a maximum of 0.27 ng g(-1)). The values of methylation potential were similar in both sediments. The results imply that the experimental determination of mercury methylation potential strongly depends on the experimental setup itself and the amount of tracer added to the system under study. It is therefore recommended to use different concentrations of tracer and perform the experiments in several replicates. The amount of mercury available for methylation in nature is usually very small. Therefore, adding very low amounts of tracer in the methylation potential studies probably gives results that have a higher environmental relevance. It is also suggested to express the results obtained in absolute amounts of MeHg produced and not just as the percentage of the added tracer.

  7. Technical efficiency of public district hospitals and health centres in Ghana: a pilot study

    PubMed Central

    Osei, Daniel; d'Almeida, Selassi; George, Melvill O; Kirigia, Joses M; Mensah, Ayayi Omar; Kainyu, Lenity H

    2005-01-01

    Background The Government of Ghana has been implementing various health sector reforms (e.g. user fees in public health facilities, decentralization, sector-wide approaches to donor coordination) in a bid to improve efficiency in health care. However, to date, except for the pilot study reported in this paper, no attempt has been made to make an estimate of the efficiency of hospitals and/or health centres in Ghana. The objectives of this study, based on data collected in 2000, were: (i) to estimate the relative technical efficiency (TE) and scale efficiency (SE) of a sample of public hospitals and health centres in Ghana; and (ii) to demonstrate policy implications for health sector policy-makers. Methods The Data Envelopment Analysis (DEA) approach was used to estimate the efficiency of 17 district hospitals and 17 health centres. This was an exploratory study. Results Eight (47%) hospitals were technically inefficient, with an average TE score of 61% and a standard deviation (STD) of 12%. Ten (59%) hospitals were scale inefficient, manifesting an average SE of 81% (STD = 25%). Out of the 17 health centres, 3 (18%) were technically inefficient, with a mean TE score of 49% (STD = 27%). Eight health centres (47%) were scale inefficient, with an average SE score of 84% (STD = 16%). Conclusion This pilot study demonstrated to policy-makers the versatility of DEA in measuring inefficiencies among individual facilities and inputs. There is a need for the Planning and Budgeting Unit of the Ghana Health Services to continually monitor the productivity growth, allocative efficiency and technical efficiency of all its health facilities (hospitals and health centres) in the course of the implementation of health sector reforms. PMID:16188021

  8. 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

  9. Study of Night Ventilation Efficiency in Urban Environment: Technical and Legal Aspects

    NASA Astrophysics Data System (ADS)

    Maragogiannis, Konstantinos; Kolokotsa, Dionysia; Maria, Efpraxia-Aithra

    2011-01-01

    Night Ventilation is a critical technique of passive cooling, as it combines a significant decrease of cooling demand and improvement of thermal comfort and indoor air quality. The aim of the present paper is to study the technical and legal aspects of night ventilation in urban climatic conditions. The technical part examines the efficiency of night ventilation techniques for urban residential buildings. Moreover, the influence of urban heat island on the night ventilation effectiveness is studied. Urban heat provokes the degradation of urban air quality and causes changes in the urban area microclimate which reduce the night ventilation effectiveness as a passive cooling technique. Moreover, this paper studies the legal framework of energy efficiency in buildings and pinpoints the institutional deficiencies of the existing regulation regarding energy efficiency and passive cooling techniques

  10. 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.

  11. Gallium(III) complexes of NOTA-bis (phosphonate) conjugates as PET radiotracers for bone imaging.

    PubMed

    Holub, Jan; Meckel, Marian; Kubíček, Vojtěch; Rösch, Frank; Hermann, Petr

    2015-01-01

    Ligands with geminal bis(phosphonic acid) appended to 1,4,7-triazacyclonone-1,4-diacetic acid fragment through acetamide (NOTAM(BP) ) or methylenephosphinate (NO2AP(BP) ) spacers designed for (68) Ga were prepared. Ga(III) complexation is much faster for ligand with methylenephosphinate spacer than that with acetamide one, in both chemical (high reactant concentrations) and radiolabeling studies with no-carrier-added (68) Ga. For both ligands, formation of Ga(III) complex was slower than that with NOTA owing to the strong out-of-cage binding of bis(phosphonate) group. Radiolabeling was efficient and fast only above 60 °C and in a narrow acidity region (pH ~3). At higher temperature, hydrolysis of amide bond of the carboxamide-bis(phosphonate) conjugate was observed during complexation reaction leading to Ga-NOTA complex. In vitro sorption studies confirmed effective binding of the (68) Ga complexes to hydroxyapatite being comparable with that found for common bis(phosphonate) drugs such as pamindronate. Selective bone uptake was confirmed in healthy rats by biodistribution studies ex vivo and by positron emission tomography imaging in vivo. Bone uptake was very high, with SUV (standardized uptake value) of 6.19 ± 1.27 for [(68) Ga]NO2AP(BP) ) at 60 min p.i., which is superior to uptake of (68) Ga-DOTA-based bis(phosphonates) and [(18) F]NaF reported earlier (SUV of 4.63 ± 0.38 and SUV of 4.87 ± 0.32 for [(68) Ga]DO3AP(BP) and [(18) F]NaF, respectively, at 60 min p.i.). Coincidently, accumulation in soft tissue is generally low (e.g. for kidneys SUV of 0.26 ± 0.09 for [(68) Ga]NO2AP(BP) at 60 min p.i.), revealing the new (68) Ga complexes as ideal tracers for noninvasive, fast and quantitative imaging of calcified tissue and for metastatic lesions using PET or PET/CT.

  12. 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

  13. 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.

  14. 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

  15. Technical and scale efficiency of public community hospitals in Eritrea: an exploratory study

    PubMed Central

    2013-01-01

    Background Eritrean gross national income of Int$610 per capita is lower than the average for Africa (Int$1620) and considerably lower than the global average (Int$6977). It is therefore imperative that the country’s resources, including those specifically allocated to the health sector, are put to optimal use. The objectives of this study were (a) to estimate the relative technical and scale efficiency of public secondary level community hospitals in Eritrea, based on data generated in 2007, (b) to estimate the magnitudes of output increases and/or input reductions that would have been required to make relatively inefficient hospitals more efficient, and (c) to estimate using Tobit regression analysis the impact of institutional and contextual/environmental variables on hospital inefficiencies. Methods A two-stage Data Envelopment Analysis (DEA) method is used to estimate efficiency of hospitals and to explain the inefficiencies. In the first stage, the efficient frontier and the hospital-level efficiency scores are first estimated using DEA. In the second stage, the estimated DEA efficiency scores are regressed on some institutional and contextual/environmental variables using a Tobit model. In 2007 there were a total of 20 secondary public community hospitals in Eritrea, nineteen of which generated data that could be included in the study. The input and output data were obtained from the Ministry of Health (MOH) annual health service activity report of 2007. Since our study employs data that are five years old, the results are not meant to uncritically inform current decision-making processes, but rather to illustrate the potential value of such efficiency analyses. Results The key findings were as follows: (i) the average constant returns to scale technical efficiency score was 90.3%; (ii) the average variable returns to scale technical efficiency score was 96.9%; and (iii) the average scale efficiency score was 93.3%. In 2007, the inefficient hospitals could

  16. 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,…

  17. 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…

  18. 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…

  19. 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…

  20. 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

  1. 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.

  2. Estimating endogenous dopamine levels at D2 and D3 receptors in humans using the agonist radiotracer [(11)C]-(+)-PHNO.

    PubMed

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

    2014-11-01

    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 [(11)C]-(+)-PHNO, the first agonist radiotracer with preferential in vivo affinity for D3R. Thus, the use of [(11)C]-(+)-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 [(11)C]-(+)-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). [(11)C]-(+)-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. [(11)C]-(+)-PHNO is a suitable radiotracer for use in estimating endogenous dopamine levels at D2R and D3R in neuropsychiatric populations.

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. The correlation between wake transition and propulsive efficiency of a flapping foil: A numerical study

    NASA Astrophysics Data System (ADS)

    Deng, Jian; Sun, Liping; Teng, Lubao; Pan, Dingyi; Shao, Xueming

    2016-09-01

    We study numerically the propulsive wakes produced by a flapping foil. Both pure pitching and pure heaving motions are considered, respectively, at a fixed Reynolds number of Re = 1700. As the major innovation of this paper, we find an interesting coincidence that the efficiency maximum agrees well with the 2D-3D transition boundary, by plotting the contours of propulsive efficiency in the frequency-amplitude parametric space and comparing to the transition boundaries. Although there is a lack of direct 3D simulations, it is reasonable to conjecture that the propulsive efficiency increases with Strouhal number until the wake transits from a 2D state to a 3D state. By comparing between the pure pitching motion and the pure heaving motion, we find that the 2D-3D transition occurs earlier for the pure heaving foil than that of the pure pitching foil. Consequently, the efficiency for the pure heaving foil peaks more closely to the wake deflection boundary than that of the pure pitching foil. Furthermore, since we have drawn the maps on the same parametric space with the same Reynolds number, it is possible to make a direct comparison in the propulsive efficiency between a pure pitching foil and a pure heaving foil. We note that the maximum efficiency for a pure pitching foil is 15.6%, and that of a pure heaving foil is 17%, indicating that the pure heaving foil has a slightly better propulsive performance than that of the pure pitching foil for the currently studied Reynolds number.

  10. Synthesis and In Vitro Evaluation of Novel Nortropane Derivatives as Potential Radiotracers for Muscarinic M2 Receptors

    PubMed Central

    Knol, Remco J. J.; van den Bos, Jan C.; Janssen, Anton G. M.; de Bruin, Kora; van Eck-Smit, Berthe L. F.; Booij, Jan

    2011-01-01

    Disturbances of the cerebral cholinergic neurotransmitter system are present in neurodegenerative disorders. SPECT or PET imaging, using radiotracers that selectively target muscarinic receptor subtypes, may be of value for in vivo evaluation of such conditions. 6β-acetoxynortropane, a potent muscarinic M2 receptor agonist, has previously demonstrated nanomolar affinity and high selectivity for this receptor. Based on this compound we synthesized four nortropane derivatives that are potentially suitable for SPECT imaging of the M2 receptor. 6β-acetoxynortropane and the novel derivatives were tested in vitro for affinity to the muscarinic M1−3 receptors. The original 6β-acetoxynortropane displayed high affinity (Ki = 70–90 nM) to M2 receptors and showed good selectivity ratios to the M1 (65-fold ratio) and the M3 (70-fold ratio) receptors. All new derivatives showed reduced affinity to the M2 subtype and loss of subtype selectivity. It is therefore concluded that the newly synthesized derivatives are not suitable for human SPECT imaging of M2 receptors. PMID:21755053

  11. Investigation of flow dynamics of liquid phase in a pilot-scale trickle bed reactor using radiotracer technique.

    PubMed

    Pant, H J; Sharma, V K

    2016-10-01

    A radiotracer investigation was carried out to measure residence time distribution (RTD) of liquid phase in a trickle bed reactor (TBR). The main objectives of the investigation were to investigate radial and axial mixing of the liquid phase, and evaluate performance of the liquid distributor/redistributor at different operating conditions. Mean residence times (MRTs), holdups (H) and fraction of flow flowing along different quadrants were estimated. The analysis of the measured RTD curves indicated radial non-uniform distribution of liquid phase across the beds. The overall RTD of the liquid phase, measured at the exit of the reactor was simulated using a multi-parameter axial dispersion with exchange model (ADEM), and model parameters were obtained. The results of model simulations indicated that the TBR behaved as a plug flow reactor at most of the operating conditions used in the investigation. The results of the investigation helped to improve the existing design as well as to design a full-scale industrial TBR for petroleum refining applications. PMID:27544314

  12. Grain boundary diffusion and segregation of Bi in Cu: radiotracer measurements in B and C diffusion regimes

    SciTech Connect

    Divinski, Sergiy; Lohmann, Maik; Herzig, Christian

    2004-08-02

    Grain boundary (GB) radiotracer diffusion of {sup 207}Bi in polycrystalline Cu was measured in Harrison's B (1198-843 K) and C (659-536 K) kinetic regimes. In the B regime the triple product P=s{center_dot}{delta}{center_dot}D{sub gb} (where s is the segregation factor and {delta} the GB width) was found to obey the Arrhenius law P=6.6x10{sup -12}xexp (-102.8 kJ mol{sup -1}/RT) m{sup 3} s{sup -1}. The measurements in the C regime yielded the temperature dependence of the Bi GB diffusion coefficient D{sub gb} in Cu, D{sub gb}=0.24xexp (-156.2 kJ mol{sup -1}/RT) m{sup 2} s{sup -1}. Assuming that {delta} congruent with 5x10{sup -10} m the segregation factor s of Bi in Cu was determined in the limit of very dilute solute concentration to follow an Arrhenius dependence s=s{sub 0}exp(-{delta}H{sub s}/RT) with the pre-exponential factor s{sub 0}=0.054 and the segregation enthalpy {delta}H{sub s}=-53.4 kJ mol{sup -1}.

  13. Investigation of flow dynamics of liquid phase in a pilot-scale trickle bed reactor using radiotracer technique.

    PubMed

    Pant, H J; Sharma, V K

    2016-10-01

    A radiotracer investigation was carried out to measure residence time distribution (RTD) of liquid phase in a trickle bed reactor (TBR). The main objectives of the investigation were to investigate radial and axial mixing of the liquid phase, and evaluate performance of the liquid distributor/redistributor at different operating conditions. Mean residence times (MRTs), holdups (H) and fraction of flow flowing along different quadrants were estimated. The analysis of the measured RTD curves indicated radial non-uniform distribution of liquid phase across the beds. The overall RTD of the liquid phase, measured at the exit of the reactor was simulated using a multi-parameter axial dispersion with exchange model (ADEM), and model parameters were obtained. The results of model simulations indicated that the TBR behaved as a plug flow reactor at most of the operating conditions used in the investigation. The results of the investigation helped to improve the existing design as well as to design a full-scale industrial TBR for petroleum refining applications.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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)

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. A review of statistical designs for improving the efficiency of phase II studies in oncology.

    PubMed

    Wason, James Ms; Jaki, Thomas

    2016-06-01

    Phase II oncology trials are carried out to assess whether an experimental anti-cancer treatment shows sufficient signs of effectiveness to justify being tested in a phase III trial. Traditionally such trials are conducted as single-arm studies using a binary response rate as the primary endpoint. In this article, we review and contrast alternative approaches for such studies. Each approach uses only data that are necessary for the traditional analysis. We consider two broad classes of methods: ones that aim to improve the efficiency using novel design ideas, such as multi-stage and multi-arm multi-stage designs; and ones that aim to improve the analysis, by making better use of the richness of the data that is ignored in the traditional analysis. The former class of methods provides considerable gains in efficiency but also increases the administrative and logistical issues in running the trial. The second class consists of viable alternatives to the standard analysis that come with little additional requirements and provide considerable gains in efficiency. PMID:26031358

  8. Efficacy and efficiency: self-designed versus instructor-designed study tools.

    PubMed

    Stern, E B; Hassanein, R S

    1992-03-01

    During the course of their education, occupational therapy students learn to administer complex structured assessments. For easier administration of these assessments, students design note cards, which then replace cumbersome test manuals during administration. This study considered whether students could learn test administration with equal efficiency and efficacy if given test administration note cards rather than having to design their own. The results showed that the subjects using instructor-designed cards earned written test and practical examination scores similar to those of the subjects using self-designed cards. The subjects using instructor-designed cards spent significantly less (p = .003) total time in study than did the subjects using self-designed cards. The difference in time between the two groups was attributable to the time spent designing note cards. Therefore, distribution of instructor-designed note cards appears to offer equally effective and significantly more efficient learning when compared with that produced when students design their own cards. The differences in efficacy and efficiency were similar for students of different learning styles (as classified by Witkin's field-dependence/field-independence continuum) [corrected].

  9. Efficiency studies of hysteretic and PWM boost converters: Controller- and battery-type effects

    NASA Astrophysics Data System (ADS)

    Sanchez, Juan Herminio, III

    A continuous conduction boost converter is studied as a function of four battery types and two controllers. The battery types are alkaline, NiCd, NiMH, and sealed lead-acid. The controllers implement voltage-mode pulse-width modulation (PWM) and hysteretic current-mode (HCM) control schemes, respectively. The boost converter is designed to produce an output of 3W at 12V DC with battery voltages ranging from 6V to 3V. The study focuses on converter efficiency as affected by battery type, controller type, and the combined effects of battery type and controller type. Computer simulations predict and experimental results verify that differences in converter efficiency between the different battery types are due to differences in capacity, current-handling capabilities, and sustained voltage levels. The HCM controller uses a control scheme, in which the switching frequency decreases as battery voltage decreases, resulting in lower MOSFET switching losses. This effect partially compensates for the increased conduction losses in converter components as more current is drawn from batteries at lower input voltages. The PWM controller has a fixed switching frequency (50 kHz) and both its switching and conduction losses increase with decreasing input voltage. Efficiency levels of 88% are achieved for higher battery voltages, decreasing to 80% for lower voltages. A difference of up to 2% higher efficiency is observed in the HCM over the PWM. The major power losses are due to the combination of the inductor's ESR and the resistance of the wire used to increase the Hall-effect current sensor turns-ratio (increasing from 400mW to 1.2W). Simulations predict that in the absence of this resistance, efficiency levels of 95% can be achieved. Conduction losses through the rectifier are in the range of 40mW to 50mW for both controllers. MOSFET switching losses amount to 50mW for both controllers at high input voltages, increasing to 100mW for the PWM, but only to 65mW for the HCM at

  10. 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.

  11. Studying nanoscale CuInSe2 for high efficient tandem cell applications

    NASA Astrophysics Data System (ADS)

    Reum Jeong, Ah; Shin, Ran Hee; Lee, Nuri; Jo, William

    2010-03-01

    We report Cu(In,Ga)Se2 nanoparticle-based cells using transparent conductive oxide back contacts. The structure is very important for next-generation tandem quantum-dot solar cells. The nanoparticles were synthesized by in-situ pulsed laser ablation and subsequently by a selenization process. X-ray diffraction, transmission electron microscopy, and atomic force microscopy of the nanoparticles were measured to study phase, crystalline information, chemical composition, and morphology. Optical characterization yielded transmission, bandgap shift, and absorption coefficient. Local current-voltage behaviors were also investigated with a contact-mode conducting scanning probe in dark and bright illuminating conditions. CdS buffer layers were found to be critical to obtain high external quantum efficiency (EQE) and energy conversion efficiency (η). More than 20 % of EQE and 1 % of η were obtained and are now being improved.

  12. 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.

  13. Nitrogen-use efficiency in maize (Zea mays L.): from 'omics' studies to metabolic modelling.

    PubMed

    Simons, Margaret; Saha, Rajib; Guillard, Lenaïg; Clément, Gilles; Armengaud, Patrick; Cañas, Rafael; Maranas, Costas D; Lea, Peter J; Hirel, Bertrand

    2014-10-01

    In this review, we will present the latest developments in systems biology with particular emphasis on improving nitrogen-use efficiency (NUE) in crops such as maize and demonstrating the application of metabolic models. The review highlights the importance of improving NUE in crops and provides an overview of the transcriptome, proteome, and metabolome datasets available, focusing on a comprehensive understanding of nitrogen regulation. 'Omics' data are hard to interpret in the absence of metabolic flux information within genome-scale models. These models, when integrated with 'omics' data, can serve as a basis for generating predictions that focus and guide further experimental studies. By simulating different nitrogen (N) conditions at a pseudo-steady state, the reactions affecting NUE and additional gene regulations can be determined. Such models thus provide a framework for improving our understanding of the metabolic processes underlying the more efficient use of N-based fertilizers. PMID:24863438

  14. 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

  15. Efficient production of high specific activity 64Cu using a biomedical cyclotron.

    PubMed

    McCarthy, D W; Shefer, R E; Klinkowstein, R E; Bass, L A; Margeneau, W H; Cutler, C S; Anderson, C J; Welch, M J

    1997-01-01

    Copper-64 (T 1/2 = 12.7 h) is an intermediate-lived positron-emitting radionuclide that is a useful radiotracer for positron emission tomography (PET) as well as a promising radiotherapy agent for the treatment for cancer. Currently, copper-64 suitable for biomedical studies is produced in the fast neutron flux trap (irradiation of zinc with fast neutrons) at the Missouri University Research Reactor. Access to the fast neutron flux trap is only possible on a weekly basis, making the availability of this tracer very limited. In order to significantly increase the availability of this intermediate-lived radiotracer, we have investigated and developed a method for the efficient production of high specific activity Cu-64 using a small biomedical cyclotron. It has been suggested that it may be possible to produce Cu-64 on a small biomedical cyclotron utilizing the 64Ni(p,n)64Cu nuclear reaction. We have irradiated both natural nickel and enriched (95% and 98%) Ni-64 plated on gold disks. Nickel has been electroplated successfully at thicknesses of approximately 20-300 mm and bombarded with proton currents of 15-45 microA. A special water-cooled target had been designed to facilitate the irradiations on a biomedical cyclotron up to 60 microA. We have shown that it is possible to separate Cu-64 from Ni-64 and other reaction byproducts rapidly and efficiently by using ion exchange chromatography. Production runs using 19-55 mg of 95% enriched Ni-64 have yielded 150-600 mCi of Cu-64 (2.3-5.0 mCi/microAh) with specific activities of 94-310 mci/microgram Cu. The cyclotron produced Cu-64 had been used to radiolabel PTSM [pyruvaldehyde bis-(N4-methylthiosemicarbazone), used to quantify myocardial, cerebral, renal, and tumor blood flow], MAb 1A3 [monoclonal antibody MAb to colon cancer], and octreotide. A recycling technique for the costly Ni-64 target material has been developed. This technique allows the nickel eluted off the column to be recovered and reused in the

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Systematic study of highly efficient white light generation in transparent materials using intense femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Dharmadhikari, A. K.; Rajgara, F. A.; Mathur, D.

    2005-01-01

    We report the results of a systematic study of white light generation in different high band-gap optical media (BaF2, acrylic, water and BK-7 glass) using ultrashort (45 fs) laser pulses. We have investigated the influence of different parameters, such as focal position of the incident laser light within the medium, the polarization state of the incident laser radiation and the pulse duration of the incident laser beam on the white light generation. Our results indicate that for intense, ultrashort pulses, the position of physical focus inside the media is crucial in the generation, with high efficiency, of white light spectra over the wavelength range 400 1100 nm. Linearly polarized incident laser light generates white light with higher intensity in the blue region than circularly polarized light. Ultrashort (45 fs) pulses generate a flatter spectrum with higher white light conversion efficiency than longer (300 fs) pulses of the same laser power. We believe that a flat response over a wide range of wavelengths in the continuum may be efficiently compressed for generation of sub-10 fs pulses.

  2. 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.

  3. The Efficiency of South African Universities: A Study Based on the Analytical Review Technique.

    ERIC Educational Resources Information Center

    Taylor, B.; Harris, G.

    2002-01-01

    Examined the relative efficiency of 10 South African universities between 1994 and 1997 using the analytical review technique. Identified the relatively efficient, relatively inefficient, and least efficient. Important efficiency factors include student population dimensions, quality and deployment of personnel resources, and allocation of…

  4. 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.

  5. 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

  6. 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.

  7. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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 programing 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 to date suggests that most of the theoretical weight-saving potential is available if design deficiencies are eliminated and strict fabrication control is exercised.

  9. Efficient Estimation of Semiparametric Transformation Models for Two-Phase Cohort Studies

    PubMed Central

    ZENG, DONGLIN; LIN, D. Y.

    2013-01-01

    Under two-phase cohort designs, such as case-cohort and nested case-control sampling, information on observed event times, event indicators, and inexpensive covariates is collected in the first phase, and the first-phase information is used to select subjects for measurements of expensive covariates in the second phase; inexpensive covariates are also used in the data analysis to control for confounding and to evaluate interactions. This paper provides efficient estimation of semiparametric transformation models for such designs, accommodating both discrete and continuous covariates and allowing inexpensive and expensive covariates to be correlated. The estimation is based on the maximization of a modified nonparametric likelihood function through a generalization of the expectation-maximization algorithm. The resulting estimators are shown to be consistent, asymptotically normal and asymptotically efficient with easily estimated variances. Simulation studies demonstrate that the asymptotic approximations are accurate in practical situations. Empirical data from Wilms’ tumor studies and the Atherosclerosis Risk in Communities (ARIC) study are presented. PMID:24659837

  10. 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.

  11. Spectroscopic and structural studies of energetically efficient transport in nanocontacts to NiSi nanowires

    NASA Astrophysics Data System (ADS)

    Stein, A.; Farhat, I. A. H.; Lacevic, N.; Bazuhair, S. K.; Azhar, S. S.; Isakovic, A. F.

    Understanding correlations between mechanical, thermal, structural and electronic transport properties of different nanocontact geometries to nanowires, such as Au/Cu-NiSi-Si, remain one of the major goals of nanodevices reliability and scalability research. Aiming to clarify the failure modes and processes that affect the energy efficiency of transport and switching in constrained nanocontact geometries, such as end contacts, we conducted the structural, spectroscopic, and noise correlation studies. We show how the spatial (in)homogeneity at and in the near vicinity of the interface affects the transport performance of the nanojunctions. Mobile Ni clusters are identified at the nanojunction interface via Raman spectromicroscopy and their influence on charge transport is analyzed. We also show that the noise correlation spectra and micro-X-ray stress-strain studies in the nanojunctions are effictive tools in predicting the energy efficiency of the nanojunctions. A computational study of the interfacial properties of metal/Ni-Si via DFT and MD simulations is implemented. Work supported by Mubadala-SRC # 2011-KJ-2190. A part of the work done at BNL-CFN, supported by DOE. A part of the work done at Cornell Univ.CFN and CCMR, supported by the NSF.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Development of a PET Radiotracer for Noninvasive Imaging of the Reactive Oxygen Species, Superoxide, in vivo

    PubMed Central

    Chu, Wenhua; Chepetan, Andre; Zhou, Dong; Shoghi, Kooresh I.; Xu, Jinbin; Dugan, Laura L.; Gropler, Robert J.; Mintun, Mark A.; Mach, Robert H.

    2014-01-01

    Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of human disease states and drug toxicities, but development of imaging tools to study ROS biology in vivo remains a challenge. Here we synthesized and validated a novel PET tracer (12) and its 18F radiolabeled version [18F]12 to allow PET (positron emission tomography) imaging of superoxide in vivo. Initial analysis of ROS reaction kinetics found that compound 12 was rapidly and selectively oxidized by superoxide, but not other ROS. Cell culture studies in EMT6 cells exposed to the cancer chemotherapeutic agent Doxorubicin (DOX), which activates the superoxide-generating enzyme, NADPH oxidase, showed that compound 12 was a sensitive and specific probe for superoxide in cells. The microPET imaging of heart in mice with DOX-induced cardiac inflammation observed 2-fold greater oxidation of [18F]12 in the DOX-treated mice compared to controls (p=0.02), the results were confirmed by distribution studies on organs subsequently removed from the mice and HPLC analysis of [18F] radioactivity compounds. These data indicate that compound 12 is a useful PET tracer to imaging ROS in vivo. PMID:24847866

  17. 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

  18. Density Functional Theory and Electrochemical Studies: Structure-Efficiency Relationship on Corrosion Inhibition.

    PubMed

    Camacho-Mendoza, Rosa L; Gutiérrez-Moreno, Evelin; Guzmán-Percástegui, Edmundo; Aquino-Torres, Eliazar; Cruz-Borbolla, Julián; Rodríguez-Ávila, José A; Alvarado-Rodríguez, José G; Olvera-Neria, Oscar; Thangarasu, Pandiyan; Medina-Franco, José L

    2015-11-23

    The relationship between structure and corrosion inhibition of a series of 30 imidazol, benzimidazol, and pyridine derivatives has been established through the investigation of quantum descriptors calculated with PBE/6-311++G**. A quantitative structure-property relationship model was obtained by examination of these descriptors using a genetic functional approximation method based on a multiple linear regression analysis. Our results indicate that the efficiency of corrosion inhibitors is strongly associated with aromaticity, electron donor ability, and molecular volume descriptors. In order to calibrate and validate the proposed model, we performed electrochemical impedance spectroscopy (EIS) studies on imidazole, 2-methylimidazole, benzimidazole, 2-chloromethylbenzimidazole, pyridine, and 2-aminopyridine compounds. The experimental values for efficiency of corrosion inhibition are in good agreement with the estimated values obtained by our model, thus confirming that our approach represents a promising and suitable tool to predict the inhibition of corrosion attributes of nitrogen containing heterocyclic compounds. The adsorption behavior of imidazole or benzimidazole heterocyclic molecules on the Fe(110) surface was also studied to elucidate the inhibition mechanism; the aromaticity played an important role in the adsorbate-surface complex.

  19. 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.

  20. 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

  1. The human component of sustainability: a study for assessing "human performances" of energy efficient construction blocks.

    PubMed

    Attaianese, Erminia; Duca, Gabriella

    2012-01-01

    This paper presents an applied research aimed at understanding the relevance and the applicability of human related criteria in sustainability assessment of construction materials. Under a theoretical perspective, human factors consideration is strongly encouraged by building sustainability assessment methods, but the practice demonstrates that current models for building sustainability assessment neglect ergonomic issues, especially those ones concerning the construction phase. The study starts from the observation that new construction techniques for high energy efficient external walls are characterized by elements generally heavier and bigger than traditional materials. In this case, high sustainability performances connected with energy saving could be reached only consuming high, and then not very much sustainable, human efforts during setting-up operations. The paper illustrates a practical approach for encompassing human factors in sustainability assessment of four block types for energy efficient external walls. Research steps, from block selections to bricklaying task analysis, human factors indicators and metrics formulation, data gathering and final assessment are going to be presented. Finally, open issues and further possible generalizations from the particular case study will be discussed.

  2. (Development of gamma emitting, receptor-binding, radiotracers for imaging the brain and pancreas)

    SciTech Connect

    Not Available

    1989-01-01

    This progress report covers the period from March 1, 1987 to Feb. 28, 1988. In studies to better understand the nature of the m-AChR receptor subtypes, we have generated a manuscript which has been submitted for publication in Life sciences entitled: The effect of chronic atropine and diisopropylfluorophosphate on rat brain muscarinic acetylcholine receptor subtype concentrations. We have also developed a more direct synthesis of 3-quinuclidinyl 4-iodobenzilate and its analogues. During this contract period, we have been involved with the synthesis of analogues 3-quinuclidinyl benzilate (QNB). We have determined the affinity constants of various compounds synthesized this year for the muscarinic receptor from rat corpus striatum. We have continued our investigation of the m-AChR in pancreas. 25 refs., 3 figs., 5 tabs.

  3. 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

  4. 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.

  5. 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.

  6. Automated reporting of pharmacokinetic study results: gaining efficiency downstream from the laboratory.

    PubMed

    Schaefer, Peter

    2011-07-01

    The purpose of bioanalysis in the pharmaceutical industry is to provide 'raw' data about the concentration of a drug candidate and its metabolites as input for studies of drug properties such as pharmacokinetic (PK), toxicokinetic, bioavailability/bioequivalence and other studies. Building a seamless workflow from the laboratory to final reports is an ongoing challenge for IT groups and users alike. In such a workflow, PK automation can provide companies with the means to vastly increase the productivity of their scientific staff while improving the quality and consistency of their reports on PK analyses. This report presents the concept and benefits of PK automation and discuss which features of an automated reporting workflow should be translated into software requirements that pharmaceutical companies can use to select or build an efficient and effective PK automation solution that best meets their needs.

  7. 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.

  8. A study of the efficiency of various Navier-Stokes solvers. [finite difference methods

    NASA Technical Reports Server (NTRS)

    Atias, M.; Wolfshtein, M.; Israeli, M.

    1975-01-01

    A comparative study of the efficiency of some finite difference methods for the solution of the Navier-Stokes equations was conducted. The study was restricted to the two-dimensional steady, uniform property vorticity-stream function equations. The comparisons were drawn by recording the CPU time required to obtain a solution as well as the accuracy of this solution using five numerical methods: central differences, first order upwind differences, second order upwind differences, exponential differences, and an ADI solution of the central difference equations. Solutions were obtained for two test cases: a recirculating eddy inside a square cavity with a moving top, and an impinging jet flow. The results show that whenever the central difference method is stable it generates results with a given accuracy for less CPU time than any other method.

  9. Advances in the development of tau PET radiotracers and their clinical applications.

    PubMed

    Okamura, Nobuyuki; Harada, Ryuichi; Furukawa, Katsutoshi; Furumoto, Shozo; Tago, Tetsuro; Yanai, Kazuhiko; Arai, Hiroyuki; Kudo, Yukitsuka

    2016-09-01

    Alzheimer's disease and other neurodegenerative dementias belong to the family of tauopathies. These diseases are characterized by the deposition of insoluble tau aggregates possessing an enriched β-sheet structure. In vivo imaging of the tau deposits by positron emission tomography (PET) will facilitate the early and accurate diagnosis of these diseases, tracking of disease progression, assessment of disease severity, and prediction of disease prognosis. Furthermore, this technology is expected to play a vital role in the monitoring of treatment outcomes and in the selection of patients for the therapeutic trials of anti-dementia drugs. Recently, several tau PET tracers have been successfully developed and demonstrated as having high binding affinity and selectivity to tau protein deposits. Recent clinical studies using these tracers have demonstrated significant tracer retention in sites susceptible to tau deposition in Alzheimer's disease, as well as correlations with the disease severity and cognitive impairment in cases with dementia. These tracers, thus, have the potential to effectively diagnose the tauopathies. Further longitudinal assessment will clarify the effect of the tau deposition on the neurodegenerative process and cognitive decline and the interaction of tau with amyloid-β in the human brain.

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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.

  15. Association analysis between feed efficiency studies and expression of hypothalamic neuropeptide genes in laying ducks.

    PubMed

    Zeng, T; Chen, L; Du, X; Lai, S J; Huang, S P; Liu, Y L; Lu, L Z

    2016-10-01

    Residual feed intake (RFI) is now considered a more reasonable metric to evaluate animal feed efficiency. In this study, the correlation between RFI and other feed efficiency traits was investigated and gene expression within the hypothalamus was determined in low RFI (LRFI) and high RFI (HRFI) ducks. Further, several hypothalamic neuropeptide genes were measured using quantitative real-time PCR. The mean feed intake value was 160 g/day, whereas the egg mass laid (EML) and body weight were approximately 62.4 g/day and 1.46 kg respectively. Estimates for heritability of RFI, feed conversion ratio (FCR) and feed intake were 0.26, 0.18 and 0.23 respectively. RFI is phenotypically positively correlated with feed intake and FCR (P < 0.01). The expression of neuropeptide Y (NPY) and neuropeptide Y receptor Y5 (NPY5R) mRNA was higher in HRFI ducks compared with LRFI ducks (P < 0.05), whereas that of proopiomelanocortin (POMC), melanocortin 4 receptor (MC4R) and cholecystokinin (CCK) was lower (P < 0.05). The mRNA expression of gonadotropin-releasing hormone 1 (luteinizing-releasing hormone) (GNRH1) and prolactin receptor (PRLR) was unchanged between LRFI and HRFI ducks. The results indicate that selection for LRFI could reduce feed intake without significant changes in EML, whereas selection on FCR will increase EML. PMID:27329478

  16. 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

  17. Evaluating Humidity Recovery Efficiency of Currently Available Heat and Moisture Exchangers: A Respiratory System Model Study

    PubMed Central

    Lucato, Jeanette Janaina Jaber; Adams, Alexander Bernard; Souza, Rogério; Torquato, Jamili Anbar; Carvalho, Carlos Roberto Ribeiro; Marini, John J

    2009-01-01

    OBJECTIVES: To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate. INTRODUCTION: Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers’ humidifying performance. METHODS: Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37°C), a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH) was calculated for each setting. RESULTS: Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow. CONCLUSIONS: Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers. PMID:19578664

  18. Association analysis between feed efficiency studies and expression of hypothalamic neuropeptide genes in laying ducks.

    PubMed

    Zeng, T; Chen, L; Du, X; Lai, S J; Huang, S P; Liu, Y L; Lu, L Z

    2016-10-01

    Residual feed intake (RFI) is now considered a more reasonable metric to evaluate animal feed efficiency. In this study, the correlation between RFI and other feed efficiency traits was investigated and gene expression within the hypothalamus was determined in low RFI (LRFI) and high RFI (HRFI) ducks. Further, several hypothalamic neuropeptide genes were measured using quantitative real-time PCR. The mean feed intake value was 160 g/day, whereas the egg mass laid (EML) and body weight were approximately 62.4 g/day and 1.46 kg respectively. Estimates for heritability of RFI, feed conversion ratio (FCR) and feed intake were 0.26, 0.18 and 0.23 respectively. RFI is phenotypically positively correlated with feed intake and FCR (P < 0.01). The expression of neuropeptide Y (NPY) and neuropeptide Y receptor Y5 (NPY5R) mRNA was higher in HRFI ducks compared with LRFI ducks (P < 0.05), whereas that of proopiomelanocortin (POMC), melanocortin 4 receptor (MC4R) and cholecystokinin (CCK) was lower (P < 0.05). The mRNA expression of gonadotropin-releasing hormone 1 (luteinizing-releasing hormone) (GNRH1) and prolactin receptor (PRLR) was unchanged between LRFI and HRFI ducks. The results indicate that selection for LRFI could reduce feed intake without significant changes in EML, whereas selection on FCR will increase EML.

  19. Synthesis of Radioisotope Mn-56@SiO2, Sm-153@SiO2, and Dy-165@SiO2 Hybrid Nanoparticles for Use as Radiotracer.

    PubMed

    Seo, Sang-Ei; Kang, Yun Ok; Jung, Sung-Hee; Choi, Seong-Ho

    2015-09-01

    Radioisotope hybrid nanoparticles (NPs) of Mn-56@SiO2, Sm-153@SiO2, and Dy-165@SiO2 were synthesized by neutron irradiation of Mn-55@SiO2, Sm-150@SiO2, and Dy-163@SiO2 NPs respectively using the HANARO research reactor. The Mn-55@SiO2, Sm-150@SiO2, and Dy-163@SiO2 NPs were synthesized by calcination in air flow at 500 degrees C for 8 h of the hybrid NPs that has been prepared by the sol-gel reaction of tetraethyl silicate in the presence of the complex precursors. Mn-55, Sm-150, and Dy-163 were selected for use as radiotracers were selected because these elements can be easily gamma-activated by neutrons (activation limits: 1 picogram (Dy), 1-10 picogram (Mn), 10-100 picogram (Sm)). The successful synthesis of the radioisotope hybrid NPs was confirmed by Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectrometry (EDS), Scanning Electron Microscopy (SEM), and Gamma Spectroscopy analysis. The synthesized the radioisotope hybrid NPs could be used as radiotracers in the scientific, environmental, engineering, and industrial fields.

  20. Theoretical study of the effect of ground proximity on the induced efficiency of helicopter rotors

    NASA Technical Reports Server (NTRS)

    Heyson, H. H.

    1977-01-01

    A study of rotors in forward flight within ground effect showed that the ground-induced interference is an upwash and a decrease in forward velocity. The interference velocities are large, oppose the normal flow through the rotor, and have large effects on the induced efficiency. Hovering with small ground clearances may result in significant blade stall. As speed is increased from hover in ground effect, power initially increases rather than decreases. At very low heights above the ground, the power requirements become nonlinear with speed as a result of the streamwise interference. The streamwise interference becomes greater as the wake approaches the ground and eventually distorts the wake to form the ground vortex which contributes to certain observed directional stability problems.

  1. 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.

  2. The Energy Efficiency Of Willow Biomass Production In Poland - A Comparative Study

    NASA Astrophysics Data System (ADS)

    Szczukowski, Stefan; Tworkowski, Józef; Stolarski, Mariusz J.; Krzyżaniak, Michał

    2015-01-01

    Field experiments with willow (Salix L.) coppice cultivation and Eko-Salix systems have been conducted at the University of Warmia and Mazury since 1992. In that wider context, the aim of the work described here was to compare energy inputs involved in setting up a plantation and producing biomass, and to assess the efficiency of willow-chips production under the coppice and Eko-Salix systems. The energy gain determined in the experiments was several to more than twenty times as great as the inputs needed to operate the plantation and to harvest willow biomass, this leaving both systems of willow cultivation under study attractive where setting up short-rotation coppices is concerned.

  3. Effects of the number of people on efficient capture and sample collection: a lion case study.

    PubMed

    Ferreira, Sam M; Maruping, Nkabeng T; Schoultz, Darius; Smit, Travis R

    2013-01-01

    Certain carnivore research projects and approaches depend on successful capture of individuals of interest. The number of people present at a capture site may determine success of a capture. In this study 36 lion capture cases in the Kruger National Park were used to evaluate whether the number of people present at a capture site influenced lion response rates and whether the number of people at a sampling site influenced the time it took to process the collected samples. The analyses suggest that when nine or fewer people were present, lions appeared faster at a call-up locality compared with when there were more than nine people. The number of people, however, did not influence the time it took to process the lions. It is proposed that efficient lion capturing should spatially separate capture and processing sites and minimise the number of people at a capture site.

  4. 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.

  5. 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

  6. Public preferences over efficiency, equity and autonomy in vaccination policy: an empirical study.

    PubMed

    Luyten, Jeroen; Dorgali, Veronica; Hens, Niel; Beutels, Philippe

    2013-01-01

    Vaccination programs increasingly have to comply with standards of evidence-based decision making. However, such a framework tends to ignore social and ethical sensitivities, risking policy choices that lack crucial public support. Research is needed under which circumstances and to which extent equity and autonomy should prevail over effectiveness and cost-effectiveness in matters of infectious disease prevention. We report on a study investigating public preferences over various vaccination policy options, based on a population survey held in Flanders, Belgium (N = 1049) between March and July 2011. We found (1) that public support varied considerably between policies that were equally efficient in preventing disease but differed according to target group or incentives to improve uptake and (2) that preferences over the use of legal compulsion, financial accountability or the offering of rewards appear to be driven by individuals' social orientation.

  7. 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)

  8. Experimental study on the spiral and oval spiral EGR cooler efficiencies in a diesel engine

    NASA Astrophysics Data System (ADS)

    Park, Sang-Ki; Lee, Jungkoo; Kim, Hyung-Man

    2014-12-01

    The cooled exhaust gas recirculation (EGR) system is one of the most effective techniques currently available for reducing nitrogen oxide emissions in diesel engine. Because the combustion characteristics in diesel engine involves high temperature and load, the amount of particulate matter (PM) emission tends to increase, thereby the PM fouling in EGR cooler degrades the heat transfer performance considerably, which in turn has a significant influence on the design of the EGR cooler. In the present study, engine dynamometer tests are performed to investigate the influences of PM fouling on the heat exchange characteristics of spiral and oval-spiral type EGR coolers equipped with a diesel engine. The evaluation test results show that the oval-spiral type EGR cooler has higher efficiency by approximate 10 % than the spiral type EGR cooler because of the increase of heat transfer area and the increased removal of PM from the deposit layer due to fluid shear force.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Correction: Theoretical study and design of multifunctional phosphorescent platinum(ii) complexes containing triarylboron moieties for efficient OLED emitters.

    PubMed

    Wu, Yong; Shan, Guo-Gang; Li, Hai-Bin; Wu, Shui-Xing; Ren, Xin-Yao; Geng, Yun; Su, Zhong-Min

    2015-02-14

    Correction for 'Theoretical study and design of multifunctional phosphorescent platinum(ii) complexes containing triarylboron moieties for efficient OLED emitters' by Yong Wu et al., Phys. Chem. Chem. Phys., 2015, DOI: .

  14. Bioconcentration of the anionic surfactant linear alkylbenzene sulfonate (LAS) in the marine shrimp Palaemonetes varians: a radiotracer study.

    PubMed

    Renaud, Florent; Warnau, Michel; Oberhänsli, François; Teyssié, Jean-Louis; Temara, Ali; Rouleau, Claude; Metian, Marc

    2014-08-15

    Uptake and depuration kinetics of dissolved [(14)C]C₁₂-6-linear alkylbenzene sulfonate (LAS) were determined in the shrimp Palaemonetes varians using environmentally relevant exposure concentration. The shrimp concentrated LAS from seawater with a mean BCF value of 120 L kg(-1) after a 7-day exposure. Uptake biokinetics were best described by a saturation model, with an estimated BCFss, of 159 ± 34 L kg(-1), reached after 11.5 days. Shrimp weight influenced significantly BCF value with smaller individuals presenting higher affinity to LAS. To the light of a whole body autoradiography, major accumulation of LAS occurred in the cephalothorax circulatory system (gills, heart, hepatopancreas) and ocular peduncle, but not in the flesh, limiting potential transfer to human consumers. LAS depuration rate constant value of the shrimp was 1.18 ± 0.08 d(-1) leading to less than 1% of remaining LAS in its tissues after 8 days of depuration.

  15. 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

  16. Enhanced detection and study of murine norovirus-1 using a more efficient microglial cell line

    PubMed Central

    Cox, Courtney; Cao, Shengbo; Lu, Yuanan

    2009-01-01

    Background Human Noroviruses are the predominant cause of non-bacterial gastroenteritis worldwide. To facilitate prevention and control, a norovirus isolated from mice can provide a model to understand human noroviruses. To establish optimal viral infectivity conditions for murine noroviruses, several cell lines of hematopoietic lineage, including murine BV-2, RAW 264.7, and TIB, as well as human CHME-5, were tested comparatively for their sensitivity to murine norovirus-1. Results Except for CHME-5, all three murine-derived cell lines were susceptible to MNV infection. Viral infection of these cells was confirmed by RT-PCR. Using both viral plaque and replication assays, BV-2 and RAW 264.7 cells were determined to have comparable sensitivities to MNV-1 infection. Comparisons of cell growth characteristics, general laboratory handling and potential in-field applications suggest the use of BV-2 to be more advantageous. Conclusion Results obtained from these studies demonstrate that an immortalized microglial cell line can support MNV-1 replication and provides a more efficient method to detect and study murine noroviruses, facilitating future investigations using MNV-1 as a model to study, detect, and control Human Norovirus. PMID:19903359

  17. A study on radon absorption efficiencies of edible oils produced in India.

    PubMed

    Karunakara, N; Al-Azmi, Darwish

    2010-04-01

    A study on absorption of radon by different edible oils of plant origins produced and used in India was conducted in order to identify efficient radon-absorbing oils. A comparative study of radon absorption by edible oils of India with that of olive oil, which is known as a good absorber of radon, was also carried out. The study was performed by bubbling known concentrations of radon through the oil contained in a bottle and then evaluating the bubbled oil by gamma-ray spectrometry using an HPGe detector. The results show that oils such as coconut oil, gingelly oil (till oil), ground nut oil, mustard oil, sunflower oil, and saffola kardi oil are also good absorbers for radon, and among them coconut oil and gingelly oils are better absorbers than olive oil. The Henry's equilibrium constant (or the concentration factor), an indicator for the solubility of gas in liquids, was also measured for different types of oil by saturating a known volume of the oil with radon. The Henry's equilibrium constant varied in the range 7.32-8.22 for the Indian vegetable oils, and for olive oil it was found to be 7.88. The details of the experimental technique employed and results obtained are presented and discussed in this paper.

  18. 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.

  19. 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.

  20. Case study: purification efficiency of a treatment wetland used at a peat extraction area

    NASA Astrophysics Data System (ADS)

    Eskelinen, Riku; Ronkanen, Anna-Kaisa; Marttila, Hannu; Kløve, Bjørn

    2014-05-01

    The inflow and outflow of a treatment wetland was intensively monitored between March 2012 and October 2012. Sampling was done with automated sampling equipment bidaily during the snowmelt period and daily for the rest of the study period. The treatment wetland is located downstream of a peat extraction area with a surface area of 208 ha. Drainage network at the peat extraction area has been fitted with peak flow control structures and a sedimentation basin from which the water is pumped to the treatment wetland. The treatment wetland has a surface area of 11 ha of peatland soil and is covered by grassy vegetation during the summer season. After flowing through the wetland water is discharging to a small stream through a v-notch weir. All samples were analysed for electric conductivity (EC), suspended solids (SS), Colour, Turbidity and pH. Additional analyses for various elements and nutrients were done for samples selected on the basis of hydrology. Results of the additional analyses represent the dissolved fraction of analysed elements as the samples were first filtrated with 0.45 µm filter for SS. Our results show that the purification efficiency varies during the measurement period. For example, to SS the overall purification efficiency was 62 %. However during the spring flood the purification efficiency is negative which can be caused by snowmelt water flushing previous year's dead vegetation or particulate matter accumulated during the winter period. After midsummer we can observe drastic increase in the retention of SS. Similar pattern can be seen in the retention of phosphorous with overall retention of 11 % of the total phosphorous. In the case of nitrogen the overall performance for the wetland is poor. Some of this can be explained by poor retention of NO2-3-N due to cold weather during spring melt season. However during the summer time denitrification process seems to be working as the retention of N improves. Retention of dissolved organic carbon

  1. 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.

  2. 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

  3. Cutting efficiency of apical preparation using ultrasonic tips with microprojections: confocal laser scanning microscopy study

    PubMed Central

    Kwak, Sang-Won; Moon, Young-Mi; Yoo, Yeon-Jee; Baek, Seung-Ho; Lee, WooCheol

    2014-01-01

    Objectives The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. Materials and Methods The apical 3-mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. Results There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Conclusions Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency. PMID:25383346

  4. 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

  5. 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

  6. 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. PMID:26910570

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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.

  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. 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

  14. Study of highly selective and efficient thiol derivatization using selenium reagents by mass spectrometry.

    PubMed

    Xu, Kehua; Zhang, Yun; Tang, Bo; Laskin, Julia; Roach, Patrick J; Chen, Hao

    2010-08-15

    This paper reports a systemic mass spectrometry (MS) investigation of a novel strategy for labeling biological thiols, involving the cleavage of the Se-N bond by thiol to form a new Se-S bond. Our data show that the reaction is highly selective, rapid, reversible, and efficient. Among 20 amino acids, only cysteine is reactive toward Se-N containing reagents and the reaction occurs in seconds. With the addition of dithiothreitol, peptides derivatized by selenium reagents can be recovered. The high reaction selectivity and reversibility provide potential in both selective identification and isolation of thiols from mixtures. Also, with dependence on the selenium reagent used, derivatized peptide ions exhibit tunable dissociation behaviors (either facile cleavage or preservation of the formed Se-S bond upon collision-induced dissociation), a feature that is useful in proteomics studies. Equally importantly, the thiol derivatization yield is striking, as reflected by 100% conversion of protein beta-lactoglobulin A using ebselen within 30 s. In addition, preliminary applications such as rapid screening of thiol peptides from mixtures and identification of the number of protein free and bound thiols have been demonstrated. The unique selenium chemistry uncovered in this study would be valuable in the MS analysis of thiols and disulfide bonds of proteins/peptides.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. On extracting design principles from biology: II. Case study-the effect of knee direction on bipedal robot running efficiency.

    PubMed

    Haberland, M; Kim, S

    2015-02-02

    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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. Study on nitrogen load reduction efficiency of agricultural conservation management in a small agricultural watershed.

    PubMed

    Liu, Xiaoli; Chen, Qiuwen; Zeng, Zhaoxia

    2014-01-01

    Different crops can generate different non-point source (NPS) loads because of their spatial topography heterogeneity and variable fertilization application rates. The objective of this study was to assess nitrogen NPS load reduction efficiency by spatially adjusting crop plantings as an agricultural conservation management (ACM) measure in a typical small agricultural watershed in the black soil region in northeast China. The assessment was undertaken using the Soil and Water Assessment Tool (SWAT). Results showed that lowland crops produce higher nitrogen NPS loads than those in highlands. It was also found that corn gave a comparatively larger NPS load than soybeans due to its larger fertilization demand. The ACM assessed was the conversion of lowland corn crops into soybean crops and highland soybean crops into corn crops. The verified SWAT model was used to evaluate the impact of the ACM action on nitrogen loads. The results revealed that the ACM could reduce NO3-N and total nitrogen loads by 9.5 and 10.7%, respectively, without changing the area of crops. Spatially optimized regulation of crop planting according to fertilizer demand and geological landscapes can effectively decrease NPS nitrogen exports from agricultural watersheds. PMID:24759530

  6. Study on nitrogen load reduction efficiency of agricultural conservation management in a small agricultural watershed.

    PubMed

    Liu, Xiaoli; Chen, Qiuwen; Zeng, Zhaoxia

    2014-01-01

    Different crops can generate different non-point source (NPS) loads because of their spatial topography heterogeneity and variable fertilization application rates. The objective of this study was to assess nitrogen NPS load reduction efficiency by spatially adjusting crop plantings as an agricultural conservation management (ACM) measure in a typical small agricultural watershed in the black soil region in northeast China. The assessment was undertaken using the Soil and Water Assessment Tool (SWAT). Results showed that lowland crops produce higher nitrogen NPS loads than those in highlands. It was also found that corn gave a comparatively larger NPS load than soybeans due to its larger fertilization demand. The ACM assessed was the conversion of lowland corn crops into soybean crops and highland soybean crops into corn crops. The verified SWAT model was used to evaluate the impact of the ACM action on nitrogen loads. The results revealed that the ACM could reduce NO3-N and total nitrogen loads by 9.5 and 10.7%, respectively, without changing the area of crops. Spatially optimized regulation of crop planting according to fertilizer demand and geological landscapes can effectively decrease NPS nitrogen exports from agricultural watersheds.

  7. 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.

  8. Transfection efficiency and structural studies on nonviral gene carriers containing cholesterol and other sterols

    NASA Astrophysics Data System (ADS)

    Evans, Heather

    2005-03-01

    Lipid based nonviral gene delivery currently focuses on cationic liposomes, which typically consist of a mixture of cationic and neutral (helper) lipids. Motivated by the plasma membrane composition of mammalian cells, which contain large amounts of cholesterol, this molecule is often used as a helper lipid. The presented work investigates the effect of cholesterol and structurally related molecules on the transfection efficiency (TE) of cationic lipid-DNA (CL-DNA) complexes in mammalian cells. Previous studies have identified the membrane charge density as a universal parameter, predicting TE for CL-DNA complexes in the lamellar Lα^C phase [1,2]. Addition of cholesterol to low transfecting CL-DNA complexes results in dramatic improvements in TE that significantly deviate from the TE model for lamellar complexes. A model system using negatively charged giant vesicles has been developed to mimic the cell membrane and understand the behavior pattern of CL-DNA complexes containing cholesterol. Funding provided by NIH GM-59288. [1] Lin AJ, Slack NL, Ahmad A, George CX, Samuel CE, Safinya CR, Biophys. J., 2003, V84:3307 [2] Ahmad A, Evans HM, Ewert K, and Safinya CR, J. Gene Med., accepted

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. [Experimental study on crop photosynthesis, transpiration and high efficient water use].

    PubMed

    Wang, Huixiao; Liu, Changming

    2003-10-01

    It is well known that the development of water-saving agriculture is a strategic choice for getting rid of the crisis of water shortage. In this paper, the crop photosynthesis, transpiration, stomatic behavior, and their affecting factors were studied in view of increasing the crop water use efficiency. The experimental results showed that there was a parabola relationship between photosynthesis and transpiration. The transpiration at the maximum photosynthesis was a critical value, above which, transpiration was the luxurious part. The luxurious transpiration could be controlled without affecting photosynthetic production. It is possible that the measures for increasing stomatic resistance and preventing transpiration could save water, and improve photosynthesis and yield as well. The photosynthesis rate increased with photosynthetic active radiation, and the light saturation point for photosynthesis existed. The light saturation point of dry treatment was much lower than that of wet treatment, and the relationship between transpiration and radiation was linear. When the photosynthetic active radiation was bigger than 1,000 mumol.m-2.s-1, some treatments could be carried out for decreasing transpiration and improving photosynthesis.

  17. 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

  18. 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

  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. 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.

  1. 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.

  2. An efficiency study of PVDF film transducers and their waveform modeling in cylindrical geometry

    SciTech Connect

    Zhang, Zhong.

    1991-12-20

    In this thesis, the efficiency formulas for a transducer working as a transmitter or a receiver was derived directively from the piezoelectric constitutive equation. The transducer efficiency in a pulse-echo measurement was also given by multiplying the efficiencies for the transmitter and the receiver. The comparison between the PVDF (polyvinylidene fluoride) film transducer and the conventional PZT ceramic transducers was made based on the efficiency formulas. Based on the impulse response approach, an analytical model was built to predict the pulse waveform for through-transmission and pulse-echo measurements when the film transducer was applied in geometry. The experiments were also made to observe echo waveforms in cylindrical rod samples. The same approach was also expanded to evaluate the echo waveforms from artificial flaws inside the cylindrical rod. The model prediction and the experimental results were in reasonably good agreement. 26 refs.

  3. 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.

  4. A study on the efficiency improvement of a single fiber guided illumination system for disposable flexible endoscope (DFE)

    NASA Astrophysics Data System (ADS)

    Bang, Hyeon Jin; Park, Byung Jun; Won, Young Jae; Lee, Seungrag

    2016-03-01

    We have studied the method to improve the illumination efficiency in DFE with optical illumination design software. We have showed the result of illumination efficiency according to the change of geometrical shape in distal tip of plastic optical fiber (POF). We simulated the illumination efficiency in the case of the polished POF distal tip and the unpolished one, respectively using optical illumination system design software. We obtained the illumination efficiency was increased by about 46 percent in the polished distal tip more than in the unpolished distal tip when a light emitting diode (LED) was directly excited to the distal tip of POF. In order to demonstrate the simulated results, we showed the polishing fabrication of the distal tip in POF and have measured the illumination efficiency of the polished POF using LED. The measured results showed that illumination efficiency was increased by about 23 percent in the polished distal tip more than in the unpolished distal tip of POF. We have demonstrated the optimized geometrical shapes of the POF for minimization of the illumination loss. We have suggested the method to improve the illumination efficiency by 69 percent for a single fiber illumination delivery system of DFE.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. Magnetism reflectometer study shows LiF layers improve efficiency in spin valve devices

    SciTech Connect

    Bardoel, Agatha A; Lauter, Valeria; Szulczewski, Greg J

    2012-01-01

    been found to enhance the injection of electrons through the semiconductor. Researchers from the University of Alabama and ORNL used polarized neutrons at the magnetism reflectometer at SNS to investigate the electronic, magnetic, and structural properties of the electrodes in a novel system. In this system, the magnetic layers cobalt and Ni{sub 80}Fe{sub 20} are interfaced with spacer layers composed of the organic semiconductor Alq3. A coupling layer of LiF is inserted to separate the magnetized layers from the semiconductor. 'ALQ3 is an organic semiconductor material,' said Lauter. 'Normally in these systems a first magnetic layer is grown on a hard substrate so that one can get the controlled magnetic parameters. Then you grow the organic semiconductor layer, followed by another magnetic material layer, such as cobalt.' In addition to determining the effect of the LiF layers on the efficiency of the electron injection, the researchers wanted to determine the magnetic properties of the cobalt and Ni{sub 80}Fe{sub 20} as well as the interfacial properties: whether there is interdiffusion of cobalt through the LiF layer to the semiconductor, for example. The researchers used polarized neutrons at beam line 4A to probe the entire, layer-by-layer assembly of the system. 'Reflectometry with polarized neutrons is a perfect method to study thin magnetic films,' Lauter said. 'These thin films - if you put one on a substrate, you see it just like a mirror. However, this mirror has a very complicated internal multilayer structure. The neutrons look inside this complicated structure and characterize each and every interface. Due to the depth sensitivity of the method, we measure the structural and magnetic properties of each layer with the resolution of 0.5 nm. The neutron scattering results found that inserting LiF as a barrier significantly improves the quality of the interface, increasing the injection of electrons from the magnetic layer through the organic semiconductor

  10. Efficient three-dimensional global models for climate studies: models I and II

    SciTech Connect

    Hansen, J.; Russell, G.; Rind, D.; Stone, P.; Lacis, A.; Lebedeff, S.; Ruedy, R.; Travis, L.

    1983-04-01

    A global atmospheric model is developed with a computational efficiency which allows long-range climate experiments. The model solves the simultaneous equations for conservation of mass, energy and momentum, and the equation of state on a grid. Differencing schemes for the dynamics are based on work of Arakawa. Cloud cover and vertical distribution are computed. Convection mixes moisture, heat and momentum, with buoyant air allowed to penetrate to a height determined by its buoyancy. Ground temperature calculations include diurnal variation and seasonal heat storage. Ground hydrology incorporates a water-holding capacity appropriate for the root zone of local vegetation. Snow depth is computed. Snow albedo includes effects of snow age and masking by vegetation. Surface fluxes are obtained from a drag-law formulation and parameterization of the Monin-Obukhov similarity relations. The initial Model I is used for 60 climate sensitivity experiments with integration times from 3 months to 5 years. These experiments determine the dependence of model simulation on various physical assumptions and model parameters. Several modifications are incorporated to produce Model II, the greatest changes arising from more realistic parameterization of the effect of boundary layer stratification on surface fluxes and the addition of friction in the top stratospheric layer to minimize effects of wave reflection from the rigid model top. The model's climate simulations are compared to observations and a brief study is made of effects of horizontal resolution. It is verified that the major features of global climate can be realistically simulated with a resolution as coarse as 1000 km, which requires an order of magnitude less computation time than used by most general circulation models. 93 references, 44 figures, 8 tables.

  11. 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

  12. Comparisons of electron acceleration efficiency among different structures during magnetic reconnection: a Cluster multicase study

    NASA Astrophysics Data System (ADS)

    Zhou, M.; Li, T.; Deng, X.; Huang, S.; Li, H.

    2015-12-01

    Magnetic reconnection has long been believed to be an efficient engine for energetic electrons production. Four different structures have been proposed for electrons being energized: flux pileup region, density cavity located around the separatrix, magnetic island and thin current sheet. In this paper, we compare the electron acceleration efficiency among these structures based on 12 magnetotail reconnection events observed by the Cluster spacecraft in 2001-2006. We used the flux ratio between the energetic electrons (> 50 keV) and lower energy electrons (< 26 keV) to quantify the electron acceleration efficiency. We do not find any specific sequence in which electrons are accelerated within these structures, though the flux pileup region, magnetic island and thin current sheet have higher probabilities to reach the maximum efficiency among the four structures than the density cavity. However, the most efficient electron energization usually occurs outside these structures. We suggest that other structures may also play important roles in energizing electrons. Our results could provide important constraints for the further modeling of electron acceleration during magnetic reconnection.

  13. 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).

  14. [Comparative experimental study of antioxidant efficiency in treatment of acute pancreatitis].

    PubMed

    Kliuĭko, D A; Korik, V E; Zhidkov, S A

    2011-01-01

    The aims of our experiments on animals were (i) to evaluate by direct oximery the efficiency of various antioxidant drugs in a complex treatment of acute pancreatitis and (ii) to determine the diagnostic value of the direct oximetry method for estimation of the efficiency of medical treatment. The article presents data obtained in a group 75 outbred Guinea with a model acute pancreatitis, which were treated with mexibel (group 1), emoxipin (group 2), end cytoflavin (group 3), with subsequent investigation of the pancreatic tissues by the direct oximetry method. The obtained results confirmed that the intraperitoneal injection of cytoflavin to animals stimulates tissue respiration, improves metabolism, promotes pancreas recovery, and also improves the prognosis and reduces the lethal outcome. The efficiency of cytoflavin within the complex therapy exceeds the effect of other antioxidants (mexibel and emoxipin) under otherwise equal conditions.

  15. 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...

  16. 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.

  17. Hathaway ''Solar Patriot'' House: A Case Study in Efficiency and Renewable Energy

    SciTech Connect

    Norton, P.; Hancock, E.; Barker, G.; Reeves, P.

    2005-05-01

    This report details the monitored and modeled performance of a solar home outside of Washington, D.C. We modeled the home energy performance using DOE2.2, performed numerous short-terms tests on the home and monitored its occupied performance for 29 months. The home uses modular construction, solar water heating, a ground-coupled heat pump, efficient appliances and compact fluorescent lighting to reduce its energy consumption by 35% compared to the Building America research benchmark home. The addition of 6kW of photovoltaics increases the savings to 67% compared to the Building America research benchmark. A more efficient shell to reduce space conditioning loads would have brought the home closer to its zero energy goals. However, even with efficient lighting and appliances, the lights, appliance and plug loads are a significant energy consumer. About 4 kW of PV are required to meet the needs of these loads alone. To achieve the zero energy goal with no further efficiency increases, the Hathaway house would need about 2.6 kW of PV in addition to the 6.0 kW it now has.

  18. A Case Study in the Measurement of Educational Efficiency in Open and Distance Learning

    ERIC Educational Resources Information Center

    Tattersall, Colin; Waterink, Wim; Hoppener, Pierre; Koper, Rob

    2006-01-01

    Open and distance learning (ODL) gives learners control of the time, place, and pace of learning, often being characterized as flexible learning. However, this flexibility goes hand-in-hand with procrastination and non-completion. As a result, the efficiency of the educational process is of importance to ODL providers, government funding agencies,…

  19. a Study of the Home Heating Index and Comparison with Other Energy-Efficiency Indices.

    NASA Astrophysics Data System (ADS)

    Huebner, Jonathan Daniel

    The Home Heating Index (HHI), with units of Btu/F(DEGREES) -day-ft('2) or W/C(DEGREES)-m('2), and related quantities have been used to evaluate the energy-efficiency of homes in Ames, Iowa during the winter of 1984-85. From these measurements, it has been discovered that the HHI can be determined to within about 10% when the energy consumption of a house is monitored for three days. However, the amount of solar radiation significantly affected the HHI of homes with a large south-glazing area, and wind speed similarly affected the HHI of homes with a high air infiltration rate. A comparison of the HHI with other indices currently in use shows that the HHI is the only consistent index when the average inside temperature of a building or its internal heat gain is varied. Most indices are flawed in that they do not take the efficiency of the heating system into consideration, or they put too much emphasis on the solar heat input. A calculation of HHI values for different types of passive solar homes from across the United States has shown that the HHI can be applied to these homes as an indicator of energy-efficiency, and that most of these homes are indeed energy-efficient.

  20. Nitrogen use efficiency goals in dairy production systems: -a review and case study examples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen use efficiency (NUE), the ratio between N outputs in products over N inputs, is often used to evaluate N use outcomes of an agricultural system and the risk of environmental N loss. In this paper we address the question what realistic NUE goals can be targeted for dairy production systems? ...

  1. 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.

  2. 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.

  3. 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…

  4. Economic rationalism and the cost efficiency of hospital chaplaincy: an Australian study.

    PubMed

    Newell, C; Carey, L B

    2000-01-01

    Health care reform is also occurring in Australia and effects hospital chaplaincy programs. "Economic rationalism" is the philosophic foundation of this effort and its contrast with the values inherit in hospital chaplaincy are highlighted. Selected research results from the Australian system are described and the authors offer a perspective on the cost efficiency of hospital chaplaincy.

  5. 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.

  6. 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…

  7. 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

  8. 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

  9. 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.

  10. Efficiency of the Technology Acceptance Model to Explain Pre-Service Teachers' Intention to Use Technology: A Turkish Study

    ERIC Educational Resources Information Center

    Teo, Timothy; Ursavas, Omer Faruk; Bahcekapili, Ekrem

    2011-01-01

    Purpose: The purpose of this study is to assess the efficiency of the technology acceptance model (TAM) to explain pre-service teachers' intention to use technology in Turkey. Design/methodology/approach: A total of 197 pre-service teachers from a Turkish university completed a survey questionnaire measuring their responses to four constructs…

  11. 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…

  12. A Further Application of the Quadriform to the Study of Economic Efficiency in K-12 Schools in Illinois.

    ERIC Educational Resources Information Center

    Genge, Fred C.

    This study presents a means of identifying economically efficient school districts in Illinois and provides an analysis of select school variables: school population; salary expenditure; level of teacher preparedness; number of years of teaching experience; and select ratios incorporating pupils, administrators, teachers, test scores, and percent…

  13. Gait energetic efficiency in older adults with and without knee pain: results from the Baltimore Longitudinal Study of Aging.

    PubMed

    Ko, Seung-Uk; Simonsick, Eleanor M; Ferrucci, Luigi

    2015-02-01

    With aging, customary gait patterns change and energetic efficiency declines, but the relationship between these alterations is not well understood. If gait characteristics that develop with aging explain part of the decline in energetic efficiency that occur in most aging individuals, then efforts to modify these characteristics could delay or prevent mobility limitation. This study characterizes gait patterns in older persons with and without knee pain and tests the hypothesis that changes in gait characteristics due to knee pain are associated with increased energetic cost of walking in older adults. Study participants were 364 men and 170 women aged 60 to 96 years enrolled in the Baltimore Longitudinal Study of Aging (BLSA), of whom 86 had prevalent knee pain. Gait patterns were assessed at participant self-selected usual pace in the gait laboratory, and the energetic cost of walking was assessed by indirect calorimetry during self-selected usual pace walking over 2.5 min in a tiled corridor using a portable equipment. Participants with knee pain were less energetically efficient than those without pain (oxygen consumption 0.97 vs. 0.88 ml/(10 m · 100 kg); p = 0.002) and had slower gait speed and smaller range of motion (ROM) at the hip and knee joints (p < 0.05, for all). Slower gait speed and lower knee ROM in participants with knee pain and longer double support time and higher ankle ROM in participants without knee pain were associated with lower energetic efficiency (p < 0.05, for all). Slower gait speed and lower knee ROM were correlates of knee pain and were found to mediate the association between age and oxygen consumption. Although knee pain is associated with a higher energetic cost of walking, gait characteristics associated with energetic efficiency differ by pain status which suggests that compensatory strategies both in the presence and absence of pain may impact gait efficiency.

  14. Efficient method for iodine radioisotope labeling of cyclooctyne-containing molecules using strain-promoted copper-free click reaction.

    PubMed

    Jeon, Jongho; Kang, Jung Ae; Shim, Ha Eun; Nam, You Ree; Yoon, Seonhye; Kim, Hye Rim; Lee, Dong Eun; Park, Sang Hyun

    2015-07-01

    Herein we report an efficient method for iodine radioisotope labeling of cyclooctyne-containing molecules using copper-free click reaction. For this study, radioiodination using the tin precursor 2 was carried out at room temperature to give (125)I-labeled azide ([(125)I]1) with high radiochemical yield (85%) and excellent radiochemical purity. Dibenzocyclooctyne (DBCO) containing cRGD peptide and gold nanoparticle were labeled with [(125)I]1 at 37°C for 30min to give triazoles with good radiochemical yields (67-95%). We next carried out tissue biodistribution study of [(125)I]1 in normal ICR mice to investigate the level of organ accumulation which needs to be considered for pre-targeted in vivo imaging. Large amount of [(125)I]1 distributed rapidly in liver and kidney from bloodstream and underwent rapid renal and hepatobiliary clearance. Moreover [(125)I]1 was found to be highly stable (>92%) in mouse serum for 24h. Therefore [(125)I]1 could be used as a potentially useful radiotracer for pre-targeted imaging. Those results clearly indicated that the present radiolabeling method using copper free click reaction would be quite useful for both in vitro and in vivo labeling of DBCO group containing molecules with iodine radioisotopes. PMID:25960325

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. Single degenerate supernova type Ia progenitors. Studying the influence of different mass retention efficiencies

    NASA Astrophysics Data System (ADS)

    Bours, M. C. P.; Toonen, S.; Nelemans, G.

    2013-04-01

    Context. There is general agreement that supernovae Ia correspond to the thermonuclear runaway of a white dwarf that is part of a compact binary, but the details of the progenitor systems are still unknown and much debated. One of the proposed progenitor theories is the single-degenerate channel in which a white dwarf accretes from a companion, grows in mass, reaches a critical mass limit, and is then consumed after thermonuclear runaway sets in. However, there are major disagreements about the theoretical delay time distribution and the corresponding time-integrated supernova Ia rate from this channel. Aims: We investigate whether the differences are due to the uncertainty in the common envelope phase and the fraction of transferred mass that is retained by the white dwarf. This so-called retention efficiency may have a strong influence on the final amount and timing of supernovae Ia. Methods: Using the population synthesis code SeBa, we simulated large numbers of binaries for various assumptions on common envelopes and retention efficiencies. We compare the resulting supernova Ia rates and delay time distributions with each other and with those from the literature, including observational data. Results: For the three assumed retention efficiencies, the integrated rate varies by a factor 3-4 to even more than a factor 100, so in extreme cases, the retention efficiency strongly suppresses the single-degenerate channel. Our different assumptions for the common envelope phase change the integrated rate by a factor 2-3. Although our results do recover the trend in the theoretical predictions from different binary population synthesis codes, they do not fully explain the large disagreement among them.

  20. 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?

  1. 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.

  2. 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.

  3. 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

  4. [Study on transmission efficiency of interference system in spatially modulated Fourier transform spectrometer].

    PubMed

    Lü, Jin-Guang; Liang, Jing-Qiu; Liang, Zhong-Zhu; Qin, Yu-Xin; Tian, Chao

    2013-03-01

    The reflection of the optic system surface and the absorption of the infrared material could reduce the transmission of the incident light in spatially modulated Fourier transform infrared spectrometer. Through the calculation of the transmission function of the interference system and the simulation of the interferogram image and recovered spectrum affected by transmission function, it was indicated that the contrast of the interferogram image declined and the spectral line intensity weakened. The theoretical analysis shows that the contrast of the interferogram image was related to the intensity reflectance of the anti-reflection film, and the attenuation of the spectrum was determined by transmission efficiency concerned with intensity reflectance R1 of the anti-reflection film, intensity reflectance R2 of the beam splitter film, and the absorption coefficient. By means of the analysis and argumentation, the absorption of the material could be ignored in our investigative wave band. So the transmission efficiency was determined only by R1 and R2. Then taking the transmission efficiency as the design target, according to the transmission required by system, the tolerance of the R1 and R2 could be gained.

  5. Impact of technical and technological changes on energy efficiency of production company - case study

    NASA Astrophysics Data System (ADS)

    Szwedzka, K.; Gruszka, J.; Szafer, P.

    2016-08-01

    Improving energy efficiency is one of the strategic objectives of the European Union for rational energy economy. To make efforts to improve energy efficiency have been obliged both small and large end-users. This article aims to show the possibilities of improving energy efficiency by introducing technical and technological process changes of pine lumber drying. The object of the research is process of drying lumber implemented in a production company, which is a key supplier of large furniture manufacturer. Pine lumber drying chamber consume about 45% of total electricity in sawmill. According to various sources, drying of 1m3 of lumber uses about 3060kWh and is dependent of inter alia: the drying process itself, the factors affecting the processing time and the desired output moisture content of the timber. The article proposals for changes in the process of drying lumber pine have been positively validated in the company, and as a result their energy consumption per 1 m3 of product declined by 18%.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. A Monte Carlo study of lung counting efficiency for female workers of different breast sizes using deformable phantoms

    NASA Astrophysics Data System (ADS)

    Hegenbart, L.; Na, Y. H.; Zhang, J. Y.; Urban, M.; Xu, X. George

    2008-10-01

    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).

  11. 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.

  12. Reduced Topological Efficiency in Cortical-Basal Ganglia Motor Network of Parkinson's Disease: A Resting State fMRI Study

    PubMed Central

    Long, Zhiliang; Wu, Guo-Rong; Hu, Xiaofei; Zhang, Yanling; Wang, Jian

    2014-01-01

    Parkinson's disease (PD) is mainly characterized by dopamine depletion of the cortico-basal ganglia (CBG) motor circuit. Given that dopamine dysfunction could affect functional brain network efficiency, the present study utilized resting-state fMRI (rs-fMRI) and graph theoretical approach to investigate the topological efficiency changes of the CBG motor network in patients with PD during a relatively hypodopaminergic state (12 hours after a last dose of dopamimetic treatment). We found that PD compared with controls had remarkable decreased efficiency in the CBG motor network, with the most pronounced changes observed in rostral supplementary motor area (pre-SMA), caudal SMA (SMA-proper), primary motor cortex (M1), primary somatosensory cortex (S1), thalamus (THA), globus pallidus (GP), and putamen (PUT). Furthermore, reduced efficiency in pre-SMA, M1, THA and GP was significantly correlated with Unified Parkinson's Disease Rating Scale (UPDRS) motor scores in PD patients. Together, our results demonstrate that individuals with PD appear to be less effective at information transfer within the CBG motor pathway, which provides a novel perspective on neurobiological explanation for the motor symptoms in patients. These findings are in line with the pathophysiology of PD, suggesting that network efficiency metrics may be used to identify and track the pathology of PD. PMID:25279557

  13. 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

  14. First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides

    NASA Astrophysics Data System (ADS)

    Sarmadian, N.; Saniz, R.; Partoens, B.; Lamoen, D.

    2016-08-01

    Cu-based chalcogenides are promising materials for thin-film solar cells with more than 20% measured cell efficiency. Using first-principles calculations based on density functional theory, the optoelectronic properties of a group of Cu-based chalcogenides Cu2-II-IV-VI4 is studied. They are then screened with the aim of identifying potential absorber materials for photovoltaic applications. The spectroscopic limited maximum efficiency (SLME) introduced by Yu and Zunger [Phys. Rev. Lett. 108, 068701 (2012)] is used as a metric for the screening. After constructing the current-voltage curve, the SLME is calculated from the maximum power output. The role of the nature of the band gap, direct or indirect, and also of the absorptivity of the studied materials on the maximum theoretical power conversion efficiency is studied. Our results show that Cu2II-GeSe4 with II = Cd and Hg, and Cu2-II-SnS4 with II = Cd, Hg, and Zn have a higher theoretical efficiency compared with the materials currently used as absorber layer.

  15. Assessing program efficiency: a time and motion study of the Mental Health Emergency Care - Rural Access Program in NSW Australia.

    PubMed

    Saurman, Emily; Lyle, David; Kirby, Sue; Roberts, Russell

    2014-08-01

    The Mental Health Emergency Care-Rural Access Program (MHEC-RAP) is a telehealth solution providing specialist emergency mental health care to rural and remote communities across western NSW, Australia. This is the first time and motion (T&M) study to examine program efficiency and capacity for a telepsychiatry program. Clinical services are an integral aspect of the program accounting for 6% of all activities and 50% of the time spent conducting program activities, but half of this time is spent completing clinical paperwork. This finding emphasizes the importance of these services to program efficiency and the need to address variability of service provision to impact capacity. Currently, there is no efficiency benchmark for emergency telepsychiatry programs. Findings suggest that MHEC-RAP could increase its activity without affecting program responsiveness. T&M studies not only determine activity and time expenditure, but have a wider application assessing program efficiency by understanding, defining, and calculating capacity. T&M studies can inform future program development of MHEC-RAP and similar telehealth programs, both in Australia and overseas. PMID:25089774

  16. 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.

  17. Assessing program efficiency: a time and motion study of the Mental Health Emergency Care - Rural Access Program in NSW Australia.

    PubMed

    Saurman, Emily; Lyle, David; Kirby, Sue; Roberts, Russell

    2014-08-01

    The Mental Health Emergency Care-Rural Access Program (MHEC-RAP) is a telehealth solution providing specialist emergency mental health care to rural and remote communities across western NSW, Australia. This is the first time and motion (T&M) study to examine program efficiency and capacity for a telepsychiatry program. Clinical services are an integral aspect of the program accounting for 6% of all activities and 50% of the time spent conducting program activities, but half of this time is spent completing clinical paperwork. This finding emphasizes the importance of these services to program efficiency and the need to address variability of service provision to impact capacity. Currently, there is no efficiency benchmark for emergency telepsychiatry programs. Findings suggest that MHEC-RAP could increase its activity without affecting program responsiveness. T&M studies not only determine activity and time expenditure, but have a wider application assessing program efficiency by understanding, defining, and calculating capacity. T&M studies can inform future program development of MHEC-RAP and similar telehealth programs, both in Australia and overseas.

  18. 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…

  19. Study of the efficiency of chemically assisted enucleation method for handmade cloning in goat (Capra hircus).

    PubMed

    Akshey, Y S; Malakar, D; De, A K; Jena, M K; Sahu, S; Dutta, R

    2011-08-01

    The present investigation was carried out to find an efficient chemically assisted procedure for enucleation of goat oocytes related to handmade cloning (HMC) technique. After 22-h in vitro maturation, oocytes were incubated with 0.5 μg/ml demecolcine for 2 h. Cumulus cells were removed by pipetting and vortexing in 0.5 mg/ml hyaluronidase, and zona pellucida were digested with pronase. Oocytes with extrusion cones were subjected to oriented bisection. One-third of the cytoplasm with the extrusion cone was removed with a micro blade. The remaining cytoplasts were used as recipients in HMC. Goat foetal fibroblasts were used as nuclear donors. The overall efficiency measured as the number of cytoplasts obtained per total number of oocytes used was significantly (p < 0.05) higher in chemically assisted handmade enucleation (CAHE) than oriented handmade enucleation without demecolcine (OHE) (80.02 ± 1.292% vs. 72.9 ± 1.00%, respectively, mean ± SEM). The reconstructed and activated embryos were cultured in embryo development medium (EDM) for 7 days. Fusion, cleavage and blastocyst development rate were 71.63 ± 1.95%, 92.94 ± 0.91% and 23.78 ± 3.33% (mean ± SEM), respectively which did not differ significantly from those achieved with random handmade enucleation and OHE. In conclusion, chemically assisted enucleation is a highly efficient and reliable enucleation method for goat HMC which eliminates the need of expensive equipment (inverted fluorescence microscope) and potentially harmful chromatin staining and ultraviolet (UV) irradiation for cytoplast selection.

  20. The radiative efficiency of relativistic jet and wind: a case study of GRB 070110

    NASA Astrophysics Data System (ADS)

    Du, Shuang; Lü, Hou-Jun; Zhong, Shu-Qing; Liang, En-Wei

    2016-11-01

    A rapidly spinning, strongly magnetized neutron star (NS) is invoked as the central engine for some gamma-ray bursts (GRBs), especially, the `internal plateau' feature of X-ray afterglow. However, for these `internal plateau' GRBs, how to produce their prompt emission remains an open question. Two different physical processes have been proposed in the literature, (1) a new-born NS is surrounded by a hyper-accreting and neutrino cooling disc, the GRB jet can be powered by neutrino annihilation aligning the spin axis; (2) a differentially rotating millisecond pulsar was formed due to different angular velocity between the interior core and outer shell parts of the NS, which can power an episodic GRB jet. In this paper, by analysing the data of one peculiar GRB 070110 (with internal plateau), we try to test which model is being favoured. By deriving the physical parameters of magnetar with observational data, the parameter regime for initial period (P0) and surface polar cap magnetic field (Bp) of the central NS are 0.96 ˜ 1.2 ms and (2.4 ˜ 3.7) × 1014 G, respectively. The radiative efficiency of prompt emission is about ηγ ˜ 6 per cent. However, the radiative efficiency of internal plateau (ηX) is larger than 31 per cent assuming the MNS ˜ 1.4 M⊙ and P0˜ 1.2 ms. The clear difference between the radiation efficiencies of prompt emission and internal plateau implies that they maybe originated from different components (e.g. prompt emission from the relativistic jet powered by neutrino annihilation, while the internal plateau from the magnetic outflow wind).

  1. 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.

  2. 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

  3. Case study on aid in district heating energy efficiency and gas transportation leakages in Russia

    SciTech Connect

    Gritsevich, I.

    1997-12-31

    Russia makes one of the greatest contribution to GHG emissions in the world and is listed in the FCCC as a country with economy in transition committed to return by the end of the present decade to its GHG emissions level in 1990. Russia has accumulated a significant reserve for carbon credit as a result of production decline: GHG emissions fell down by 25% in 1995/1990, and one of the greatest energy efficiency potentials (more than 480 mln tce). Russia is interested in international cooperation, for instance, in the form of JI projects.

  4. Study on Efficient Numerical Simulation Technology of Mold Filling Process of Casting

    NASA Astrophysics Data System (ADS)

    Yang, Liushuan; Wang, Xiao; Huang, Jinliang; Zhang, Shaoli

    The paper based on the SOLA-VOF, depended on the meaning of the equation result in the algebra and geometry, brings forward a new idea and the rapid iterative arithmetic. According to the rapid iterative arithmetic, a program of the rapid calculating method of flow field and the numerical simulation experiment using the standard casting have been made by the author. The result showed that the calculating efficiency has increased by 3~4 times than before, the accuracy equals to the SOLA-VOF, which can meet the requirements of the application.

  5. 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

  6. Will intra-specific differences in transpiration efficiency in wheat be maintained in a high CO₂ world? A FACE study.

    PubMed

    Tausz-Posch, Sabine; Norton, Robert M; Seneweera, Saman; Fitzgerald, Glenn J; Tausz, Michael

    2013-06-01

    This study evaluates whether the target breeding trait of superior leaf level transpiration efficiency is still appropriate under increasing carbon dioxide levels of a future climate using a semi-arid cropping system as a model. Specifically, we investigated whether physiological traits governing leaf level transpiration efficiency, such as net assimilation rates (A(net)), stomatal conductance (g(s)) or stomatal sensitivity were affected differently between two Triticum aestivum L. cultivars differing in transpiration efficiency (cv. Drysdale, superior; cv. Hartog, low). Plants were grown under Free Air Carbon dioxide Enrichment (FACE, approximately 550 µmol mol⁻¹ or ambient CO₂ concentrations (approximately 390 µmol mol⁻¹). Mean A(net) (approximately 15% increase) and gs (approximately 25% decrease) were less affected by elevated [CO₂] than previously found in FACE-grown wheat (approximately 25% increase and approximately 32% decrease, respectively), potentially reflecting growth in a dry-land cropping system. In contrast to previous FACE studies, analyses of the Ball et al. model revealed an elevated [CO₂] effect on the slope of the linear regression by 12% indicating a decrease in stomatal sensitivity to the combination of [CO₂], photosynthesis rate and humidity. Differences between cultivars indicated greater transpiration efficiency for Drysdale with growth under elevated [CO₂] potentially increasing the response of this trait. This knowledge adds valuable information for crop germplasm improvement for future climates. PMID:23035842

  7. Will intra-specific differences in transpiration efficiency in wheat be maintained in a high CO₂ world? A FACE study.

    PubMed

    Tausz-Posch, Sabine; Norton, Robert M; Seneweera, Saman; Fitzgerald, Glenn J; Tausz, Michael

    2013-06-01

    This study evaluates whether the target breeding trait of superior leaf level transpiration efficiency is still appropriate under increasing carbon dioxide levels of a future climate using a semi-arid cropping system as a model. Specifically, we investigated whether physiological traits governing leaf level transpiration efficiency, such as net assimilation rates (A(net)), stomatal conductance (g(s)) or stomatal sensitivity were affected differently between two Triticum aestivum L. cultivars differing in transpiration efficiency (cv. Drysdale, superior; cv. Hartog, low). Plants were grown under Free Air Carbon dioxide Enrichment (FACE, approximately 550 µmol mol⁻¹ or ambient CO₂ concentrations (approximately 390 µmol mol⁻¹). Mean A(net) (approximately 15% increase) and gs (approximately 25% decrease) were less affected by elevated [CO₂] than previously found in FACE-grown wheat (approximately 25% increase and approximately 32% decrease, respectively), potentially reflecting growth in a dry-land cropping system. In contrast to previous FACE studies, analyses of the Ball et al. model revealed an elevated [CO₂] effect on the slope of the linear regression by 12% indicating a decrease in stomatal sensitivity to the combination of [CO₂], photosynthesis rate and humidity. Differences between cultivars indicated greater transpiration efficiency for Drysdale with growth under elevated [CO₂] potentially increasing the response of this trait. This knowledge adds valuable information for crop germplasm improvement for future climates.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. A study of the relative efficiencies of three commercially available dehydrated Rappaport-Vassiliadis media.

    PubMed Central

    Quail, E.; McGibbon, L.; Fricker, C. R.

    1986-01-01

    The relative efficiencies of three commercially available dehydrated Rappaport-Vassiliadis media have been compared with a similar medium prepared from individual constituents in our own laboratory. An inoculation ratio of 1:100 was found to be optimal for each of the media tested. Laboratory produced RV-medium was significantly better than the three commercial preparations after 24 h incubation. However, when the duration of incubation was extended to 48 h, there was no significant difference in the number of salmonella isolates obtained when using our own RV medium and that produced by Oxoid Ltd and Difco Ltd (P greater than 0.05). All of these three media were, however, significantly more effective than the medium produced by Lab.M. (P less than 0.01). PMID:3734428

  15. Efficient cascaded parameter scan approach for studying top-off safety in storage rings

    NASA Astrophysics Data System (ADS)

    Li, Yongjun; Yang, Lingyun; Krinsky, Samuel

    2011-03-01

    We introduce a new algorithm, which we call the cascaded parameter scan method, to efficiently carry out the scan over magnet parameters in the safety analysis for top-off injection in synchrotron radiation storage rings. In top-off safety analysis, one must track particles populating phase space through a beam line containing magnets and apertures and clearly demonstrate that, for all possible magnet settings and errors, all particles are lost on scrapers within the properly shielded region. In the usual approach, if one considers m magnets and scans each magnet through n setpoints, then one must carry out nm tracking runs. In the cascaded parameter scan method, the number of tracking runs is reduced to n×m. This reduction of exponential to linear dependence on the number of setpoints n greatly reduces the required computation time and allows one to more densely populate phase space and to increase the number n of setpoints scanned for each magnet.

  16. 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.

  17. 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.

  18. Positioning matrix of economic efficiency and complexity: a case study in a university hospital.

    PubMed

    Ippolito, Adelaide; Viggiani, Vincenzo

    2014-01-01

    At the end of 2010, the Federico II University Hospital in Naples, Italy, initiated a series of discussions aimed at designing and applying a positioning matrix to its departments. This analysis was developed to create a tool able to extract meaningful information both to increase knowledge about individual departments and to inform the choices of general management during strategic planning. The name given to this tool was the positioning matrix of economic efficiency and complexity. In the matrix, the x-axis measures the ratio between revenues and costs, whereas the y-axis measures the index of complexity, thus showing "profitability" while bearing in mind the complexity of activities. By using the positioning matrix, it was possible to conduct a critical analysis of the characteristics of the Federico II University Hospital and to extract useful information for general management to use during strategic planning at the end of 2010 when defining medium-term objectives.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. Designing validation studies more efficiently according to the modular approach: retrospective analysis of the EPISKIN test for skin corrosion.

    PubMed

    Hoffmann, Sebastian; Hartung, Thomas

    2006-05-01

    It is claimed that the modular approach to validation, which involves seven independent modules, will make the assessment of test validity more flexible and more efficient. In particular, the aspects of between-laboratory variability and predictive capacity are formally separated. Here, the main advantage of the approach is to offer the opportunity for reduced labour, and thus to allow study designs to be more time efficient and cost effective. The impact of this separation was analysed by taking the ECVAM validation study on in vitro methods for skin corrosivity as an example of a successful validation study - two of its methods triggered new OECD test guidelines. Lean study designs, which reduced the number of tests required by up to 60%, were simulated with the original validation data for the EPISKIN model. By using resampling techniques, we were able to demonstrate the effects of the lean designs on three between-laboratory variability measures and on the predictive capacity in terms of sensitivity and specificity, in comparison with the original study. Overall, the study results, especially the levels of confidence, were only slightly affected by the lean designs that were modelled. It is concluded that the separation of the two modules is a promising way to speed-up prospective validation studies and to substantially reduce costs, without compromising study quality.

  4. 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...

  5. 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...

  6. Depuration and uptake kinetics of I, Cs, Mn, Zn and Cd by the earthworm (Lumbricus terrestris) in radiotracer-spiked litter

    SciTech Connect

    Sheppard, S.C.; Evenden, W.G.; Cornwell, T.C.

    1997-10-01

    The relative depuration and uptake kinetics of contaminants should be known to interpret appropriately the use of organisms such as earthworms in environmental bioassays and monitoring. For example, 14-d earthworm bioassays should be interpreted with the knowledge that some contaminants will continue to accumulate in tissues for months. The radiotracers {sup 125}I, {sup 134}Cs, {sup 54}Mn, {sup 65}Zn, and {sup 109}Cd were applied to deciduous litter and specimens of Lumbricus terrestris were exposed, either to litter alone or to litter on the top of soil columns. Depuration was monitored for 120 d and uptake, in a separate experiment, for 20 d. Both depuration and uptake were described using two-phase, first-order statistical models. Cut clearance had a mean half-time of 1.4 d. The mean half-time for physiological depuration decreased from I (210 d) > Cd (150 d) > Zn (69 d) > Mn (40 d) > Cs (24 d). Both the depuration and the uptake experiments were necessary to resolve even partially the multiphase processes. Earthworm/soil dry weight concentration ratios decreased from Cd > Zn > I {ge} Cs {ge} Mn. The very slow kinetics indicate that tissue concentrations will increase continuously for a long time, with important implications for subsequent food-chain transfers.

  7. Metabolism, distribution, and excretion of deoxynivalenol with combined techniques of radiotracing, high-performance liquid chromatography ion trap time-of-flight mass spectrometry, and online radiometric detection.

    PubMed

    Wan, Dan; Huang, Lingli; Pan, Yuanhu; Wu, Qinghua; Chen, Dongmei; Tao, Yanfei; Wang, Xu; Liu, Zhenli; Li, Juan; Wang, Liye; Yuan, Zonghui

    2014-01-01

    Dispositions of deoxynivalenol (DON) in rats and chickens were investigated, using a radiotracer method coupled with a novel γ-accurate radioisotope counting (γ-ARC) radio-high-performance liquid chromatography ion trap time-of-flight tandem mass spectrometry (radio-HPLC-IT-TOF-MS/MS) system. 3β-(3)H-DON was chemically synthesized and orally administrated to both sexes of rats and chickens as single or multiple doses. The results showed that DON was widely distributed and quickly eliminated in all tissues. The highest concentration was found in the gastrointestinal tract at 6 h post-administration. Substantially lower levels were detected in the kidney, liver, heart, lung, spleen, and brain. Three new metabolites were identified tentatively as 10-deoxynivalenol-sulfonate, 10-deepoxy-deoxynivalenol (DOM-1)-sulfonate, and deoxynivalenol-3α-sulfate. Deoxynivalenol-3α-sulfate was a major metabolite in chickens, while the major forms in rats were DOM-1 and DON. Additionally, a higher excretion rate in urine was observed in female rats than in male rats. The differences in metabolite profiles and excretion rates, which suggested diverse ways to detoxify, may relate to the different tolerances in different genders or species.

  8. (54)Mn Radiotracers Demonstrate Continuous Dissolution and Reprecipitation of Vernadite (δ-MnO2) during Interaction with Aqueous Mn(II).

    PubMed

    Elzinga, Evert J

    2016-08-16

    (54)Mn radiotracers were used to assess Mn atom exchange between aqueous Mn(II) and vernadite (δ-MnO2) at pH 5.0. Continuous solid-liquid redistribution of (54)Mn atoms occurred, and systems are near isotopic equilibrium after reaction for 3 months. Despite this extensive exchange, X-ray diffraction and X-ray absorption spectroscopy data showed no major changes in vernadite bulk mineralogy. These results demonstrate that the vernadite-Mn(II) interface is dynamic, with the substrate undergoing continuous dissolution and reprecipitation mediated by aqueous Mn(II) without observable impacts on its mineralogy. Interfacial redox reactions between adsorbed Mn(II) and solid-phase Mn(IV) and Mn(III) are proposed as the main drivers of this process. Interaction between aqueous Mn(II) and structural Mn(III) likely involves interfacial electron transfer coupled with Mn atom exchange. The exchange of aqueous Mn(II) and solid-phase Mn(IV) is more complex and is proposed to result from coupled interfacial comproportionation-disproportionation reactions, where electron transfer from adsorbed Mn(II) to lattice Mn(IV) produces transient Mn(III) species that disproportionate to regenerate aqueous Mn(II) and structural Mn(IV). These findings provide further evidence of the importance of Mn(II)(aq)-MnO2(s) interactions and the attendant production of transient Mn(III) intermediates to the geochemical functioning of phyllomanganates in environments undergoing Mn redox cycling.

  9. 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

  10. Technology installation review. A case study on energy-efficient technologies

    SciTech Connect

    Baxter, Van

    2001-12-31

    The purpose of this Technology Installation Review is to provide an overview of hybrid geothermal heat pump systems. It presents the results of recent research on these systems, looks at system types, energy savings, maintenance considerations, and measured technology performance from several examples. Using the ground as a thermal energy source and/or a heat sink for heat pumps has long been recognized to have a number of advantages over the similar use of ambient air. Ground temperatures at about 3-ft depth or lower are much less variable than ambient air temperatures. Further, soil or rock at these depths is usually warmer than ambient air during the coldest winter months and cooler than ambient air during the summer months. This fact leads directly to cooler condensation temperatures (during cooling operation) and warmer evaporating temperatures (during heating) for a heat pump with consequent improved energy efficiency. It also results in increased heating and cooling capacity at extreme temperatures, thereby reducing or eliminating the need for auxiliary heat.

  11. 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

  12. Design principles for high efficiency small-grain polysilicon solar cells, with supporting experimental studies

    NASA Technical Reports Server (NTRS)

    Lindholm, F. A.; Neugroschel, A.; Sah, C. T.

    1982-01-01

    Design principles suggested here aim toward high conversion efficiency (greater than 15 percent) in polysilicon cells. The principles seek to decrease the liabilities of both intragranular and grain-boundary-surface defects. The advantages of a phosphorus atom concentration gradient in a thin (less than 50 microns) base of a p(+)/n(x)/n(+) drift-field solar cell, which produces favorable gradients in chemical potential, minority-carrier mobility and diffusivity, and recombination lifetime (via phosphorus gettering) are suggested. The degrading effects of grain boundaries are reduced by these three gradients and by substituting atoms (P, H, F or Li) for vacancies on the grain-boundary surface. From recent experiments comes support for the benefits of P diffusion down grain boundaries and, for quasi-grain-boundary-free and related structures. New analytic solutions for the n(x)-base include the effect of a power-law dependence between P concentration and lifetime. These provide an upper-bound estimate on the open circuit voltage. Finite-difference numerical solutions of the six Shockley equations furnish complete information about all solar-cell parameters and add insight concerning design.

  13. 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.

  14. 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

  15. [Studies on high efficient plant regeneration system from anther callus of Bupleurum chinense].

    PubMed

    Xu, Jie-Sen; Zhao, Li-Zi; Wei, Jian-He; Tao, Yun-Wen; Sun, Jing; Sui, Chun; Yang, Cheng-Min

    2013-11-01

    The callus of Bupleurum chinense with anthers at the stage of uninucleate was induced. After several subcultures, anther calli of B. chinense were cultured at 20 MS culture mediums with different plant hormones to differentiate into plantlets. Differentiation of callus was detected after 21 and 49 days to select the most effective medium. There were 19 culture mediums in which anther callus could differentiate into plantlets with differentiation rate range from 3% to 60% , and most less than 20%. MS + KT 0.5 mg x L(-1) + sucrose 30 g c L(-1) + phytagel 5 g x L(-1) was the best differentiation medium with the differentiation rate of 60%, followed by MS + ZT 1.0 mg x L(-1) + sucrose 30 g x L(-1) + phytagel 5 g x L(-1) with the differentiation rate of 58%. Then plantlets were transferred to rooting medium to obtain whole plant. All plantlets could root in the rooting medium of MS + sucrose 30 g x L(-1) + phytagel 5 g x L(-1) and 1/2 MS + NAA 0.5 mg x L(-1) + sucrose 30 g x L(-1) + phytagel of 5 g L(-1) with the rooting rate of 100%. As a result, the high efficient and stable plant regeneration system was established from anther callus of B. chinense. PMID:24494550

  16. 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.

  17. 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.

  18. 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}.

  19. Study of Displacement Efficiency and Flow Behavior of Foamed Gel in Non-Homogeneous Porous Media

    PubMed Central

    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

  20. The practicality of nanoceria-PAN-based (68)Ge/(68)Ga generator toward preparation of (68)Ga-labeled cyclic RGD dimer as a potential PET radiotracer for tumor imaging.

    PubMed

    Chakraborty, Sudipta; Chakravarty, Rubel; Sarma, Haladhar D; Dash, Ashutosh; Pillai, M R A

    2013-02-01

    Cyclic RGD (Arg-Gly-Asp) peptides radiolabeled with (68)Ga have great potential for the early tumor detection and noninvasive monitoring of tumor metastasis and therapeutic response. Herein, the preparation of (68)Ga-labeled DOTA-E[c(RGDfK)](2) (DOTA=1,4,7,10-tetraazacylododecane-1,4,7,10-tetracetic acid; E=Glutamic acid; R=Arginine; G=Glycine; D=Aspartic acid; f=phenyl alanine; K=lysine) using (68)Ga directly eluted from a nanoceria-polyacrylonitrile (CeO(2)-PAN)-based (68)Ge/(68)Ga generator developed in-house was reported. The (68)Ga complex of DOTA-E[c(RGDfK)](2) was synthesized with >98% radiochemical purity by incubating 20 μg of the conjugate with (68)GaCl(3) (74-111 MBq) in acetate buffer (pH 3.5-4.0) at 90°C for 10 minutes. The complex exhibited excellent in vitro stability in 0.1 M EDTA solution at room temperature upto 1 hour studied (radiochemical purity: 98.0%). The biological efficacy of the radiolabeled conjugate was studied in C57/BL6 mice bearing melanoma tumors. The results of the biodistribution studies revealed significant tumor uptake (4.14±0.54%ID/g) within 10 minutes postinjection (p.i.), which increased further to 4.61±0.31%ID/g at 30 minutes p.i. The tumor-to-blood ratio was found to increase from 1.75±0.42 at 10 minutes p.i. to 2.25±0.20 at 60 minutes p.i., whereas the tumor-to-liver and tumor-to-muscle ratio between the same time points increased from 2.71±0.76 to 3.31±0.84 and 5.37±1.08 to 8.97±1.32, respectively. The study successfully demonstrated the preparation of (68)Ga-DOTA-E[c(RGDfK)](2) as a potential positron-emission tomography radiotracer for possible use in tumor imaging by using (68)Ga eluted from a reliable, easy-to-handle (68)Ge/(68)Ga generator developed in-house, without any postelution purification of (68)Ga.

  1. 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.

  2. 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

  3. Powerful and Cost-Efficient Designs for Longitudinal Intervention Studies with Two Treatment Groups

    ERIC Educational Resources Information Center

    Moerbeek, Mirjam

    2008-01-01

    Three issues need to be decided in the design stage of a longitudinal intervention study: the number of persons, the number of repeated measurements per person, and the duration of the study. The degree to which polynomial effects vary across persons and the drop-out pattern also influence the statistical power to detect intervention effects. This…

  4. A rapid and efficient method to study the function of crop plant transporters in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Iron (Fe) is an essential micronutrient for humans. Fe deficiency disease is wide-spread and has lead to extensive studies on the mechanisms of Fe uptake and storage, especially in staple food crops such as rice. However, studies of functionally related genes in rice and other crops are often time a...

  5. 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.

  6. 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.

  7. Factors affecting the technical efficiency of health systems: A case study of Economic Cooperation Organization (ECO) countries (2004–10)

    PubMed Central

    Ravangard, Ramin; Hatam, Nahid; Teimourizad, Abedin; Jafari, Abdosaleh

    2014-01-01

    Background: Improving efficiency of health sector is of particular importance in all countries. To reach this end, it is paramount to measure the efficiency. On the other hand, there are many factors that affect the efficiency of health systems. This study aimed to measure the Technical Efficiency (TE) of health systems in Economic Cooperation Organization (ECO) countries during 2004–10 and to determine the factors affecting their TE. Methods: This was a descriptive-analytical and panel study. The required data were gathered using library and field studies, available statistics and international websites through completing data collection forms. In this study, the TE of health systems in 10 ECO countries was measured using their available data and Data Envelopment Analysis (DEA) through two approaches. The first approach used GDP per capita, education and smoking as its inputs and life expectancy and infant mortality rates as the outputs. The second approach, also, used the health expenditures per capita, the number of physicians per thousand people, and the number of hospital beds per thousand people as its inputs and life expectancy and under-5 mortality rates as the outputs. Then, the factors affecting the TE of health systems were determined using the panel data logit model. Excel 2010, Win4Deap 1.1.2 and Stata 11.0 were used to analyze the collected data. Results: According to the first approach, the mean TE of health systems was 0.497 and based on the second one it was 0.563. Turkey and Turkmenistan had, respectively, the highest and lowest mean of efficiency. Also, the results of panel data logit model showed that only GDP per capita and health expenditures per capita had significant relationships with the TE of health systems. Conclusion: In order to maximize the TE of health systems, health policy-makers should pay special attention to the proper use of healthcare resources according to the people’s needs, the appropriate management of the health

  8. 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

  9. Coagulation efficiency, organic-matter glues and the dynamics of particles during a phytoplankton bloom in a mesocosm study

    NASA Astrophysics Data System (ADS)

    Dam, Hans G.; Drapeau, David T.

    The combination of phytoplankton aggregate formation and subsequent sedimentation has been proposed as a mechanism for termination of phytoplankton blooms. To test this hypothesis, the evolution of a phytoplankton bloom was studied in a mesocosm. During a seven-day period, the concentration and size of small particles (<51-μm equivalent spherical diameter) and their coagulation efficiency, or stickiness, which is the probability that when particles collide they will remain together, was measured daily. During the study, the concentration of particles increased eight-fold, their mean volume increased six-fold and their volume fraction increased 45 fold. Particle stickiness dropped from 0.8 at the beginning to <0.1 towards the end of the study and was positively correlated with particle growth rate. These results are opposite of what has been speculated to occur during phytoplankton blooms. The relationship between stickiness and putative organic-matter glues, such as transparent exopolymer particles (TEP) and carbohydrates, was examined. Particle stickiness was strongly correlated with the chlorophyll weight-specific TEP concentration and the chlorophyll weight-specific carbohydrate concentration (both total and surface-active fraction). These relationships also hold if TEP and carbohydrate concentrations are normalized by other measures of volume or mass of particles. These results, on the relationship between particle stickiness and the chlorophyll weight-specific concentration of putative organic-matter glues (TEP, surface-active carbohydrates), can explain previous observations that the coagulation efficiency of particles declines with time during blooms. Employing the observed particle concentrations, sizes and coagulation efficiencies, the critical concentration at which growth of particles is balanced by losses due to coagulation and subsequent sedimentation was estimated. The estimates of the critical concentration towards the end of the study are in good

  10. 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.

  11. Bactericidal efficiency and mode of action: a comparative study of photochemistry and photocatalysis.

    PubMed

    Pigeot-Rémy, S; Simonet, F; Atlan, D; Lazzaroni, J C; Guillard, C

    2012-06-15

    In order to compare the disinfection potential of photocatalysis and photochemistry, the effects of these two processes on bacteria in water were investigated under exposure to UV-A and UV-C. The well-known bacterial model Escherichia coli (E. coli) was used as the experimental organism. Radiation exposure was produced with an HPK 125 W lamp and the standard TiO(2) Degussa P-25 was used as the photocatalyst. Firstly, the impact of photocatalysis and photochemistry on the cultivability of bacterial cells was investigated. UV-A radiation resulted in low deleterious effects on bacterial cultivability but generated colonies of size smaller than average. UV-C photocatalysis demonstrated a greater efficiency than UV-A photocatalysis in altering bacterial cultivability. From a cultivability point of view only, UV-C radiation appeared to be the most deleterious treatment. A rapid epifluorescence staining method using the LIVE/DEAD Bacterial Viability Kit was then used to assess the modifications in bacterial membrane permeability. UV-A radiation did not induce any alterations in bacterial permeability for 420 min of exposure whereas only a few minutes of exposure to UV-C radiation, with the same total radiance intensity, induced total loss of permeability. Moreover, after 20 and 60 min of exposure to UV-C and UV-A photocatalysis respectively, all bacteria lost their membrane integrity, suggesting that the bacterial envelope is the primary target of reactive oxygen species (ROS) generated at the surface of TiO(2) photocatalyst. These results were further confirmed by the formation of malondialdehyde (MDA) during the photocatalytic inactivation of bacterial cells and suggest that destruction of the cell envelope is a key step in the bactericidal action of photocatalysis. The oxidation of bacterial membrane lipids was also correlated with the monitoring of carboxylic acids, which can be considered as representatives of lipid peroxidation by-products. Finally, damages to

  12. Enhancement of Magma Mixing Efficiency by Chaotic Dynamics: an Experimental Study

    NASA Astrophysics Data System (ADS)

    Perugini, D.; de Campos, C. P.; Ertel, W.; Dingwell, D. B.; Poli, G.

    2010-12-01

    important petrological implications. In particular: (1) it is shown that, in contrast with current thinking, magmas with highly contrasting rheology can mix, thus extending significantly the spectrum of geological conditions under which magma mixing processes can occur efficiently; (2) the geochemical modelling of mixing process cannot be performed using the classical linear two-end-member mixing model; and (3) the chemical compositions on short-length scales represent snapshots within the process of chaotic mixing and, therefore, must be considered as transient compositions. Their connection to the composition of original end-members is, thus, not trivial. This implies that microanalysis on short-length scales may provide misleading information on the parental composition of magmas.

  13. Automated synthesis and dosimetry of 6-deoxy-6-[18F]fluoro-D-fructose (6-[18F]FDF): a radiotracer for imaging of GLUT5 in breast cancer

    PubMed Central

    Bouvet, Vincent; Jans, Hans S; Wuest, Melinda; Soueidan, Olivier-Mohamad; Mercer, John; McEwan, Alexander JB; West, Frederick G; Cheeseman, Chris I; Wuest, Frank

    2014-01-01

    6-Deoxy-6-[18F]fluoro-D-fructose (6-[18F]FDF) is a promising PET radiotracer for imaging GLUT5 in breast cancer. The present work describes GMP synthesis of 6-[18F]FDF in an automated synthesis unit (ASU) and dosimetry calculations to determine radiation doses in humans. GMP synthesis and dosimetry calculations are important prerequisites for first-in-human clinical studies of 6-[18F]FDF. The radiochemical synthesis of 6-[18F]FDF was optimized and adapted to an automated synthesis process using a Tracerlab FXFN ASU (GE Healthcare). Starting from 30 GBq of cyclotron-produced n.c.a. [18F]fluoride, 2.9 ± 0.1 GBq of 6-[18F]FDF could be prepared within 50 min including HPLC purification resulting in an overall decay-corrected radiochemical yield of 14 ± 3% (n = 11). Radiochemical purity exceeded 95%, and the specific activity was greater than 5.1 GBq/μmol. Sprague-Dawley rats were used for biodistribution experiments, and dynamic and static small animal PET experiments. Biodistribution studies served as basis for allometric extrapolation to the standard man anatomic model and normal organ-absorbed dose calculations using OLINDA/EXM software. The calculated human effective dose for 6-[18F]FDF was 0.0089 mSv/MBq. Highest organ doses with a dose equivalent of 0.0315 mSv/MBq in a humans were found in bone. Injection of 370 MBq (10 mCi) of 6-[18F]FDF results in an effective whole body radiation dose of 3.3 mSv in humans, a value comparable to that of other 18F-labeled PET radiopharmaceuticals. The optimized automated synthesis under GMP conditions, the good radiochemical yield and the favorable human radiation dosimetry estimates support application of 6-[18F]FDF in clinical trials for molecular imaging of GLUT5 in breast cancer patients. PMID:24795839

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.