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Sample records for 11c fluence build-up

  1. Osteoporosis: Build Up Your Bones!

    MedlinePlus

    ... of this page please turn Javascript on. Feature: Osteoporosis Build Up Your Bones! Past Issues / Winter 2011 ... special needs of people with osteoporosis. A Complete Osteoporosis Program Remember, exercise is only one part of ...

  2. Electron-Cloud Build-Up: Summary

    SciTech Connect

    Furman, M.A.

    2007-06-18

    I present a summary of topics relevant to the electron-cloud build-up and dissipation that were presented at the International Workshop on Electron-Cloud Effects 'ECLOUD 07' (Daegu, S. Korea, April 9-12, 2007). This summary is not meant to be a comprehensive review of the talks. Rather, I focus on those developments that I found, in my personal opinion, especially interesting. The contributions, all excellent, are posted in http://chep.knu.ac.kr/ecloud07/.

  3. E-Cloud Build-up in Grooved Chambers

    SciTech Connect

    Venturini, Marco

    2007-05-01

    We simulate electron cloud build-up in a grooved vacuumchamber including the effect of space charge from the electrons. Weidentify conditions for e-cloud suppression and make contact withprevious estimates of an effective secondary electron yield for groovedsurfaces.

  4. Prediction of sulphide build-up in filled sewer pipes.

    PubMed

    Alani, Amir M; Faramarzi, Asaad; Mahmoodian, Mojtaba; Tee, Kong Fah

    2014-08-01

    Millions of dollars are being spent worldwide on the repair and maintenance of sewer networks and wastewater treatment plants. The production and emission of hydrogen sulphide has been identified as a major cause of corrosion and odour problems in sewer networks. Accurate prediction of sulphide build-up in a sewer system helps engineers and asset managers to appropriately formulate strategies for optimal sewer management and reliability analysis. This paper presents a novel methodology to model and predict the sulphide build-up for steady state condition in filled sewer pipes. The proposed model is developed using a novel data-driven technique called evolutionary polynomial regression (EPR) and it involves the most effective parameters in the sulphide build-up problem. EPR is a hybrid technique, combining genetic algorithm and least square. It is shown that the proposed model can provide a better prediction for the sulphide build-up as compared with conventional models. PMID:24956763

  5. Build Up Your Bones! | NIH MedlinePlus the Magazine

    MedlinePlus

    ... turn Javascript on. Feature: Osteoporosis Build Up Your Bones! Past Issues / Winter 2011 Table of Contents Exercise ... who have been diagnosed with osteoporosis. The Best Bone-Building Exercise The best exercise for your bones ...

  6. Pressure build-up characteristics in Austin Chalk wells

    SciTech Connect

    Claycomb, E.

    1983-02-28

    Pressure build-up data collected from wells in the Giddings Austin Chalk field have been analyzed through use of techniques currently available to the petroleum industry. The slope of ..delta..T vs. ..delta..P, along with a Horner graph and knowledge of well history, should indicate which method of analysis is applicable. The operator should know what kind of stimulation, if any; was performed on the well and the degree of success. A Horner graph, along with a graph of ..delta..T vs. ..delta..P should be plotted as a matter of course. Information gained from proper analysis of build-up data may be used both in well diagnosis and in prediction of well performance. In well diagnosis, a pressure buildup-falloff test is one of the few means of analyzing a problem well. Properly analyzed build-up data will give estimates of average reservoir pressure, in situ permeability, and fracture length. These data will aid in fracture optimization, reserve prediction, and performance prediction.

  7. Atomic Oxygen Fluence Monitor

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.

    2011-01-01

    This innovation enables a means for actively measuring atomic oxygen fluence (accumulated atoms of atomic oxygen per area) that has impinged upon spacecraft surfaces. Telemetered data from the device provides spacecraft designers, researchers, and mission managers with real-time measurement of atomic oxygen fluence, which is useful for prediction of the durability of spacecraft materials and components. The innovation is a compact fluence measuring device that allows in-space measurement and transmittance of measured atomic oxygen fluence as a function of time based on atomic oxygen erosion yields (the erosion yield of a material is the volume of material that is oxidized per incident oxygen atom) of materials that have been measured in low Earth orbit. It has a linear electrical response to atomic oxygen fluence, and is capable of measuring high atomic oxygen fluences (up to >10(exp 22) atoms/sq cm), which are representative of multi-year low-Earth orbital missions (such as the International Space Station). The durability or remaining structural lifetime of solar arrays that consist of polymer blankets on which the solar cells are attached can be predicted if one knows the atomic oxygen fluence that the solar array blanket has been exposed to. In addition, numerous organizations that launch space experiments into low-Earth orbit want to know the accumulated atomic oxygen fluence that their materials or components have been exposed to. The device is based on the erosion yield of pyrolytic graphite. It uses two 12deg inclined wedges of graphite that are over a grit-blasted fused silica window covering a photodiode. As the wedges erode, a greater area of solar illumination reaches the photodiode. A reference photodiode is also used that receives unobstructed solar illumination and is oriented in the same direction as the pyrolytic graphite covered photodiode. The short-circuit current from the photodiodes is measured and either sent to an onboard data logger, or

  8. Progressive Fracture of Fiber Composite Build-Up Structures

    NASA Technical Reports Server (NTRS)

    Gotsis, Pascal K.; Chamis, C. C.; Minnetyan, Levon

    1997-01-01

    Damage progression and fracture of built-up composite structures is evaluated by using computational simulation. The objective is to examine the behavior and response of a stiffened composite (0/ +/- 45/90)(sub s6) laminate panel by simulating the damage initiation, growth, accumulation, progression and propagation to structural collapse. An integrated computer code, CODSTRAN, was augmented for the simulation of the progressive damage and fracture of built-up composite structures under mechanical loading. Results show that damage initiation and progression have significant effect on the structural response. Influence of the type of loading is investigated on the damage initiation, propagation and final fracture of the build-up composite panel.

  9. Dark solitons in laser radiation build-up dynamics.

    PubMed

    Woodward, R I; Kelleher, E J R

    2016-03-01

    We reveal the existence of slowly decaying dark solitons in the radiation build-up dynamics of bright pulses in all-normal dispersion mode-locked fiber lasers, numerically modeled in the framework of a generalized nonlinear Schrödinger equation. The evolution of noise perturbations to quasistationary dark solitons is examined, and the significance of background shape and soliton-soliton collisions on the eventual soliton decay is established. We demonstrate the role of a restoring force in extending soliton interactions in conservative systems to include the effects of dissipation, as encountered in laser cavities, and generalize our observations to other nonlinear systems. PMID:27078358

  10. Electron Cloud Build-up Study for DAFNE

    SciTech Connect

    Vaccarezza, C.; Cimino, R.; Drago, A.; Zobov, M.; Bellodi, G.; Schulte, D.; Zimmermann, F.; Rumolo, G.; Ohmi, K.; Pivi, M.; /SLAC

    2005-05-27

    After the first experimental observations compatible with the presence of the e-cloud effect in the DAFNE positron ring, a more systematic study has been performed regarding the e-cloud build-up. The measured field map of the magnetic field has been taken into account in the simulation for elements present in the four 10 m long bending sections, representing 40% of the whole positron ring. The obtained simulation results are presented together with the recent experimental observations performed on the vacuum behavior of the positron ring.

  11. Design and automated production of 11C-alpha-methyl-l-tryptophan (11C-AMT).

    PubMed

    Huang, Xuan; Xiao, Xia; Gillies, Robert J; Tian, Haibin

    2016-05-01

    (11)C-alpha-methyl-l-tryptophan ([(11)C]AMT), a tryptophan metabolism PET tracer, has successfully been employed for brain serotonin pathway and indoleamine 2,3-dioxygenase (IDO) pathway related tumor imaging. We here report a reliable, automated procedure for routine synthesis of [(11)C]AMT based on an Eckert and Ziegler Modular-Lab system. The semi-preparative HPLC was incorporated into the system to improve chemical purity and specific activity. The 6-step radiosynthesis followed by HPLC-purification provided [(11)C]AMT in 5.3±1.2% (n=6, non-decay-corrected) overall radiochemical yield with radiochemical purity >99% and specific activity of 35-116GBq/μmol. Usually, 2.95±0.65GBq (n=6, EOS) patient ready dose was produced from about 55.5GBq [(11)C]CO2 in 50min. PMID:27150033

  12. Flammable gas cloud build up in a ventilated enclosure.

    PubMed

    Ivings, M J; Gant, S E; Saunders, C J; Pocock, D J

    2010-12-15

    Ventilation is frequently used as a means for preventing the build up of flammable or toxic gases in enclosed spaces. The effectiveness of the ventilation often has to be considered as part of a safety case or risk assessment. In this paper methods for assessing ventilation effectiveness for hazardous area classification are examined. The analysis uses data produced from Computational Fluid Dynamics (CFD) simulations of low-pressure jet releases of flammable gas in a ventilated enclosure. The CFD model is validated against experimental measurements of gas releases in a ventilation-controlled test chamber. Good agreement is found between the model predictions and the experimental data. Analysis of the CFD results shows that the flammable gas cloud volume resulting from a leak is largely dependent on the mass release rate of flammable gas and the ventilation rate of the enclosure. The effectiveness of the ventilation for preventing the build up of flammable gas can therefore be assessed by considering the average gas concentration at the enclosure outlet(s). It is found that the ventilation rate of the enclosure provides a more useful measure of ventilation effectiveness than considering the enclosure air change rate. PMID:20855156

  13. Preflare energy build-up in a filament circuit

    NASA Technical Reports Server (NTRS)

    Martens, P. C. H.

    1987-01-01

    The May 16, 1981 flare observed at Debrecen is studied by extending to a fully three-dimensional model the two-dimensional Van Tend and Kuperus (1978) scenario for preflare energy build-up. It is shown that there are 10 to the 33rd ergs of free energy available to explain the subsequent large two-ribbon flare. As a result of the three-dimensional character of the present model, this estimate is an order of magnitude larger than that made by Van Tend. It is confirmed that the global form of the preflare circuit is highly important in determining the amount of energy stored in the preflare configuration. The present model gives correct predictions for the independently observed photospheric flow velocity and current strength in filaments.

  14. Progressive Fracture of Fiber Composite Build-Up Structures

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Gotsis, Pascal K.; Chamis, C. C.

    1997-01-01

    Damage progression and fracture of built-up composite structures is evaluated by using computational simulation. The objective is to examine the behavior and response of a stiffened composite (0 +/-45/90)(sub s6) laminate panel by simulating the damage initiation, growth, accumulation, progression and propagation to structural collapse. An integrated computer code CODSTRAN was augmented for the simulation of the progressive damage and fracture of built-up composite structures under mechanical loading. Results show that damage initiation and progression to have significant effect on the structural response. Influence of the type of loading is investigated on the damage initiation, propagation and final fracture of the build-up composite panel.

  15. Electron-Cloud Build-Up: Theory and Data

    SciTech Connect

    Furman, M. A.

    2010-10-08

    We present a broad-brush survey of the phenomenology, history and importance of the electron-cloud effect (ECE). We briefly discuss the simulation techniques used to quantify the electron-cloud (EC) dynamics. Finally, we present in more detail an effective theory to describe the EC density build-up in terms of a few effective parameters. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire 'ECLOUD' series. In addition, the proceedings of the various flavors of Particle Accelerator Conferences contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC.

  16. Quiet Spike Build-Up Ground Vibration Testing Approach

    NASA Technical Reports Server (NTRS)

    Spivey, Natalie D.; Herrera, Claudia Y.; Truax, Roger; Pak, Chan-gi; Freund, Donald

    2007-01-01

    NASA's Dryden Flight Research Center uses a modified F-15B (836) aircraft as a testbed for a variety of flight research:experiments mounted underneath the aircraft fuselage. The F-15B was selected to fly Gulfstream Aerospace Corporation's (GAC)QuietSpike(TM)(QS) project; however, this experiment is very unique and unlike any of the previous testbed experiments flown on the F-15B. It involves the addition of a relatively long quiet spike boom attached to the radar bulkhead of the aircraft. This QS experiment is a stepping stone to airframe structural morphing technologies designed to mitigate sonic born strength of business jets over land. The QS boom is a concept in Which an aircraft's front-end would be extended prior to supersonic acceleration. This morphing would effectively lengthen the aircraft, reducing peak sonic boom amplitude, but is also expected to partition the otherwise strong bow shock into a series of reduced-strength, non-coalescing shocklets. Prior to flying the Quietspike(TM) experiment on the F-15B aircraft several ground vibration tests (GVT) were required in order to understand the QS modal characteristics and coupling effects with the F-15B. However, due to the project's late hardware delivery of the QS and the intense schedule, a "traditional" GVT of the mated F-1513 Quietspike(tm) ready-for-flight configuration would not have left sufficient time available for the finite element model update and flutter analyses before flight testing. Therefore, a "nontraditional" ground vibration testing approach was taken. The objective of the QuietSpike (TM) build-up ground testing approach was to ultimately obtain confidence in the F-15B Quietspike(TM) finite element model (FEM) to be used for the flutter analysis. In order to obtain the F15B QS FEM with reliable foundation stiffness between the QS and the F-15B radar bulkhead as well as QS modal characteristics, several different GVT configurations were performed. EAch of the four GVT's performed had a

  17. 1-/sup 11/C-D-glucose and related compounds

    SciTech Connect

    Shiue, C.Y.; Wolf, A.P.

    1982-01-26

    The novel compounds 1-/sup 11/C-D-glucose, 1-/sup 11/C-D-mannose, 1-/sup 11/C-D-galactose, 2-/sup 11/C-D-glucose, 2-/sup 11/C-D-mannose and 2-/sup 11/C-D-galactose which can be used in nuclear medicine to monitor the metabolism of glucose and galactose can be rapidly prepared by reaction of the appropriate aldose substrate with an alkali metal /sup 11/C-labeled cyanide followed by reduction with a Raney alloy in formic acid.

  18. 1-.sup.11 C-D-Glucose and related compounds

    DOEpatents

    Shiue, Chyng-Yann; Wolf, Alfred P.

    1984-03-27

    The novel compounds 1-.sup.11 C-D-glucose, 1-.sup.11 C-D-mannose, 1-.sup.11 C-D-galactose, 2-.sup.11 C-D-glucose, 2-.sup.11 C-D-mannose and 2-.sup.11 C-D-galactose which can be used in nuclear medicine to monitor the metabolism of glucose and galactose can be rapidly prepared by reaction of the appropriate aldose substrate with an alkali metal .sup.11 C-labeled cyanide followed by reduction with a Raney alloy in formic acid.

  19. Synthesis of [11C]Am80 via Novel Pd(0)-Mediated Rapid [11C]Carbonylation Using Arylboronate and [11C]Carbon Monoxide

    PubMed Central

    2012-01-01

    11C-labeled methylbenzoates [11C]4a–d were synthesized using Pd(0)-mediated rapid cross-coupling reactions employing [11C]carbon monoxide and arylboronic acid neopentyl glycol esters 3a–d under atmospheric pressure in methanol–dimethylformamide (MeOH–DMF), in radiochemical yields of 12 ± 5–26 ± 13% (decay-corrected based on [11C]O). The reaction conditions were highly favorable for the synthesis of [11C]Am80 ([11C]2) and [11C]methyl 4-((5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalen-2-yl)carbamoyl)benzoate ([11C]2-Me) using 4-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalen-2-yl)benzamide (5), both of which produced a decay-corrected radiochemical yield (RCY) of 26 ± 13%, with >99% radiochemical purity and an average specific radioactivity of 44 GBq/μmol. The yields of [11C]4a, [11C]2-Me, and [11C]2 were improved by the use of a 2-fold excess of the solvents and reagents under the same conditions to give respective yields of 66 ± 8, 65 ± 7, and 48 ± 2%. PMID:24900383

  20. Synthesis of [(11)C]Am80 via Novel Pd(0)-Mediated Rapid [(11)C]Carbonylation Using Arylboronate and [(11)C]Carbon Monoxide.

    PubMed

    Takashima-Hirano, Misato; Ishii, Hideki; Suzuki, Masaaki

    2012-10-11

    (11)C-labeled methylbenzoates [(11)C]4a-d were synthesized using Pd(0)-mediated rapid cross-coupling reactions employing [(11)C]carbon monoxide and arylboronic acid neopentyl glycol esters 3a-d under atmospheric pressure in methanol-dimethylformamide (MeOH-DMF), in radiochemical yields of 12 ± 5-26 ± 13% (decay-corrected based on [(11)C]O). The reaction conditions were highly favorable for the synthesis of [(11)C]Am80 ([(11)C]2) and [(11)C]methyl 4-((5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalen-2-yl)carbamoyl)benzoate ([(11)C]2-Me) using 4-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-N-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalen-2-yl)benzamide (5), both of which produced a decay-corrected radiochemical yield (RCY) of 26 ± 13%, with >99% radiochemical purity and an average specific radioactivity of 44 GBq/μmol. The yields of [(11)C]4a, [(11)C]2-Me, and [(11)C]2 were improved by the use of a 2-fold excess of the solvents and reagents under the same conditions to give respective yields of 66 ± 8, 65 ± 7, and 48 ± 2%. PMID:24900383

  1. Optimization of [11C]HCN production and no-carrier-added [1-11C]amino acid synthesis.

    PubMed

    Iwata, R; Ido, T; Takahashi, T; Nakanishi, H; Iida, S

    1987-01-01

    The optimal conditions for the catalytic production of [11C]HCN from [11C]CO2 were investigated. [11C]CO2 was reduced to [11C]CH4 with H2 on Ni and then converted to [11C]HCN by reaction with NH3 on Pt in a radiochemical yield of more than 95% under the optimized conditions of an NH3 concentration of 5 vol%, a Pt furnace temperature of 920 degrees C, and a reaction gas flow rate of over 200 mL/min. Absorbers were used to remove O2 and H2O from the reaction gas. The synthesis of no-carrier-added [1-11C]amino acids from [11C]HCN via [11C]aminonitriles was successfully carried out. This method is suitable for automation of [1-11C]amino acid production. PMID:3032866

  2. Opacity Build-up in Impulsive Relativistic Sources

    SciTech Connect

    Granot, Jonathan; Cohen-Tanugi, Johann; Silva, Eduardo do Couto e

    2007-09-28

    Opacity effects in relativistic sources of high-energy gamma-rays, such as gamma-ray bursts (GRBs) or Blazars, can probe the Lorentz factor of the outflow as well as the distance of the emission site from the source, and thus help constrain the composition of the outflow (protons, pairs, magnetic field) and the emission mechanism. Most previous works consider the opacity in steady state. Here we study the effects of the time dependence of the opacity to pair production ({gamma}{gamma} {yields} e{sup +}e{sup -}) in an impulsive relativistic source, which may be relevant for the prompt gamma-ray emission in GRBs or flares in Blazars. We present a simple, yet rich, semi-analytic model for the time and energy dependence of the optical depth, {tau}{gamma}{gamma}, in which a thin spherical shell expands ultra-relativistically and emits isotropically in its own rest frame over a finite range of radii, R{sub 0} {le} R {le} R{sub 0}+{Delta}R. This is particularly relevant for GRB internal shocks. We find that in an impulsive source ({Delta}R {approx}< R{sub 0}), while the instantaneous spectrum (which is typically hard to measure due to poor photon statistics) has an exponential cutoff above the photon energy {var_epsilon}1(T) where t{gamma}{gamma}({var_epsilon}1) = 1, the time integrated spectrum (which is easier to measure) has a power-law high-energy tail above the photon energy {var_epsilon}1* {approx} {var_epsilon}1({Delta}T) where {Delta}T is the duration of the emission episode. Furthermore, photons with energies {var_epsilon} > {var_epsilon}1* are expected to arrive mainly near the onset of the spike in the light curve or flare, which corresponds to the short emission episode. This arises since in such impulsive sources it takes time to build-up the (target) photon field, and thus the optical depth {tau}{gamma}{gamma}({var_epsilon}) initially increases with time and {var_epsilon}1(T) correspondingly decreases with time, so that photons of energy {var_epsilon} > {var

  3. Understanding the build-up of SMBH and Galaxies

    NASA Astrophysics Data System (ADS)

    Carrera, Francisco; Georgakakis, Antonis; Ueda, Yoshihiro; Akylas, Thanassis; Lanzuisi, Giorgio; Castello, N.

    2015-09-01

    . The excellent survey capabilities of Athena/WFI (effective area, angular resolution, field of view) will allow to measure the incidence of feedback in the shape of warm absorbers and Ultra Fast Outflows among the general population of AGN, as well as to complete the census of black hole growth by detecting and characterising significant samples of the most heavily obscured (including Compton thick) AGN, to redshifts z~3-4. The outstanding spectral throughput and resolution of Athena/X-IFU will permit measuring the energetics of those outflows to assess their influence on their host galaxies. The demographics of the heavily obscured and outflowing populations relative to their hosts are fundamental for understanding how major black hole growth events relate to the build-up of galaxies.

  4. High molar activity of [11C]TCH346 via [11C]methyl triflate using the "wet" [11C]CO2 reduction method.

    PubMed

    Ermert, Johannes; Stüsgen, Stefan; Lang, Markus; Roden, Werner; Coenen, Heinz H

    2008-05-01

    [(11)C]TCH346, a compound acting on the glycolytic enzyme, glycerol-aldehyde-3-phosphate dehydrogenase, was produced under optimised conditions by methylation of the desmethyl compound with no-carrier added (n.c.a.) [(11)C]methyl triflate. An i.v. injectable solution of n.c.a. [(11)C]TCH346 containing 4040+/-1550 MBq (n=6) containing a molar activity between 40 and 5700 GBq/micromol and a radiochemical purity of >99% was obtained within 30 min (after EOB) by irradiation of nitrogen gas containing 0.5% oxygen with 16.5 MeV protons at 45 microA for 30 min. The alkylation reagent [(11)C]methyl triflate was prepared via on-line conversion of [(11)C]methyl iodide. For the formation of [(11)C]methyl iodide, [(11)C]carbon dioxide from the target chamber was reduced by a lithium aluminium hydride solution, and the methanol obtained on-line was converted using triphenylphosphine diiodide. The molar activity of [(11)C]TCH346 could be improved from 40 up to nearly 5700GB q/micromol during the optimisation of the synthesis using the same stock solution of lithium aluminium hydride solution in tetrahydrofuran. PMID:17827025

  5. Synthesis of (11)C-labeled retinoic acid, [(11)C]ATRA, via an alkenylboron precursor by Pd(0)-mediated rapid C-[(11)C]methylation.

    PubMed

    Suzuki, Masaaki; Takashima-Hirano, Misato; Ishii, Hideki; Watanabe, Chika; Sumi, Kengo; Koyama, Hiroko; Doi, Hisashi

    2014-08-01

    Retinoids are a class of chemical compounds which include both natural dietary vitamin A (retinol) metabolites and active synthetic analogs. Both experimental and clinical studies have revealed that retinoids regulate a wide variety of essential biological processes. In this study, we synthesized (11)C-labeled all-trans-retinoic acid (ATRA), the most potent biologically active metabolite of retinol and used in the treatment of acute promyelocytic leukemia. The synthesis of (11)C-labeled ATRA was accomplished by a combination of rapid Pd(0)-mediated C-[(11)C]methylation of the corresponding pinacol borate precursor prepared by 8 steps and hydrolysis. [(11)C]ATRA will prove useful as a PET imaging agent, particularly for elucidating the improved therapeutic activity of ATRA (natural retinoid) for acute promyelocytic leukemia by comparing with the corresponding PET probe [(11)C]Tamibarotene (artificial retinoid). PMID:24930828

  6. Process variability of pollutant build-up on urban road surfaces.

    PubMed

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2015-06-15

    Knowledge of the pollutant build-up process is a key requirement for developing stormwater pollution mitigation strategies. In this context, process variability is a concept which needs to be understood in-depth. Analysis of particulate build-up on three road surfaces in an urban catchment confirmed that particles <150 μm and >150 μm have characteristically different build-up patterns, and these patterns are consistent over different field conditions. Three theoretical build-up patterns were developed based on the size-fractionated particulate build-up patterns, and these patterns explain the variability in particle behavior and the variation in particle-bound pollutant load and composition over the antecedent dry period. Behavioral variability of particles <150 μm was found to exert the most significant influence on the build-up process variability. As characterization of process variability is particularly important in stormwater quality modeling, it is recommended that the influence of behavioral variability of particles <150 μm on pollutant build-up should be specifically addressed. This would eliminate model deficiencies in the replication of the build-up process and facilitate the accounting of the inherent process uncertainty, and thereby enhance the water quality predictions. PMID:25777949

  7. Taxonomy of factors which influence heavy metal build-up on urban road surfaces.

    PubMed

    Liu, An; Gunawardana, Chandima; Gunawardena, Janaka; Egodawatta, Prasanna; Ayoko, Godwin A; Goonetilleke, Ashantha

    2016-06-01

    Heavy metals build-up on urban road surfaces is a complex process and influenced by a diverse range of factors. Although numerous research studies have been conducted in the area of heavy metals build-up, limited research has been undertaken to rank these factors in terms of their influence on the build-up process. This results in limitations in the identification of the most critical factor/s for accurately estimating heavy metal loads and for designing effective stormwater treatment measures. The research study undertook an in-depth analysis of the factors which influence heavy metals build-up based on data generated from a number of different geographical locations around the world. Traffic volume was found to be the highest ranked factor in terms of influencing heavy metals build-up while land use was ranked the second. Proximity to arterial roads, antecedent dry days and road surface roughness has a relatively lower ranking. Furthermore, the study outcomes advances the conceptual understanding of heavy metals build-up based on the finding that with increasing traffic volume, total heavy metal build-up load increases while the variability decreases. The outcomes from this research study are expected to contribute to more accurate estimation of heavy metals build-up loads leading to more effective stormwater treatment design. PMID:26897571

  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. An efficient and practical radiosynthesis of [11C]temozolomide

    PubMed Central

    Moseley, Christian K.; Carlin, Stephen M.; Neelamegam, Ramesh

    2014-01-01

    Temozolomide (TMZ) is a prodrug for an alkylating agent used for the treatment of malignant brain tumors. A positron emitting version, [11C]TMZ, has been utilized to help elucidate the mechanism and biodistribution of TMZ. Challenges in [11C]TMZ synthesis and reformulation make it difficult for routine production. Herein we report a highly reproducible one-pot radiosynthesis of [11C]TMZ with a radiochemical yield of 17±5% and >97% radiochemical purity. PMID:23151019

  10. No-carrier-added [1.sup.11 c]putrescine

    DOEpatents

    McPherson, Daniel W.; Fowler, Joanna S.; Wolf, Alfred P.

    1989-01-01

    The invention relates to a new radiolabeled imaging agent, no-carrier-added [1-.sup.11 C]putrescine, and to the use of this very pure material as a radiotracer with positron emission tomography for imaging brain tumors. The invention further relates to the synthesis of no-carrier-added [1-.sup.11 C]putrescine based on the Michael addition of potassium .sup.11 C-labeled cyanide to acrylonitrile followed by reduction of the .sup.11 C-labeled dinitrile. The new method is rapid and efficient and provides radiotracer with a specific activity greater than 1.4 curies per millimol and in a purity greater than 95%.

  11. Characterizing polycyclic aromatic hydrocarbon build-up processes on urban road surfaces.

    PubMed

    Liu, Liang; Liu, An; Li, Dunzhu; Zhang, Lixun; Guan, Yuntao

    2016-07-01

    Reliable prediction models are essential for modeling pollutant build-up processes on urban road surfaces. Based on successive samplings of road deposited sediments (RDS), this study presents empirical models for mathematical replication of the polycyclic aromatic hydrocarbon (PAH) build-up processes on urban road surfaces. The contaminant build-up behavior was modeled using saturation functions, which are commonly applied in US EPA's Stormwater Management Model (SWMM). Accurate fitting results were achieved in three typical urban land use types, and the applicability of the models was confirmed based on their acceptable relative prediction errors. The fitting results showed high variability in PAH saturation value and build-up rate among different land use types. Results of multivariate data and temporal-based analyses suggested that the quantity and property of RDS significantly influenced PAH build-up. Furthermore, pollution sources, traffic parameters, road surface conditions, and sweeping frequency could synthetically impact the RDS build-up and RDS property change processes. Thus, changes in these parameters could be the main reason for variations in PAH build-up in different urban land use types. PMID:27086074

  12. Absorbed dose measurements in the build-up region of flattened versus unflattened megavoltage photon beams.

    PubMed

    De Puysseleyr, Annemieke; Lechner, Wolfgang; De Neve, Wilfried; Georg, Dietmar; De Wagter, Carlos

    2016-06-01

    This study evaluated absorbed dose measurements in the build-up region of conventional (FF) versus flattening filter-free (FFF) photon beams. The absorbed dose in the build-up region of static 6 and 10MV FF and FFF beams was measured using radiochromic film and extrapolation chamber dosimetry for single beams with a variety of field sizes, shapes and positions relative to the central axis. Removing the flattening filter generally resulted in slightly higher relative build-up doses. No considerable impact on the depth of maximum dose was found. PMID:27020966

  13. Electron contamination and build-up doses in conformal radiotherapy fields.

    PubMed

    Hounsell, A R; Wilkinson, J M

    1999-01-01

    The dose in the build-up region depends upon the primary photon beam, backscattered radiation from the patient and contamination radiation from outside the patient. In this paper, a model based on measured data is proposed which allows the build-up dose for arbitrarily shaped treatment fields to be determined. The dose in the build-up region is assumed to comprise a primary photon component and a contamination component that is a function of the field size and shape. This contamination component, for modelling purposes, is subdivided into contributions that correspond to elements of 1 cm by 1 cm cross-sectional area at the plane of the isocentre. The magnitude of these components has been obtained by fitting measured data to an exponential function. The exponent was found to vary linearly with depth for energies between 4 MV and 20 MV. The coefficient decreased linearly with depth at 4, 6 and 8 MV, but exhibited a broad build-up region at 20 MV. The primary component, in the build-up region, could be approximated by a 100 - (100 - PSD) e(-mu d) function, where PSD is the primary surface dose. The values obtained during the fitting procedure were used to calculate dose in the build-up region for arbitrarily shaped fields. Good agreement was found in each case. PMID:10071874

  14. Assessing uncertainty in pollutant build-up and wash-off processes.

    PubMed

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2016-05-01

    Assessing build-up and wash-off process uncertainty is important for accurate interpretation of model outcomes to facilitate informed decision making for developing effective stormwater pollution mitigation strategies. Uncertainty inherent to pollutant build-up and wash-off processes influences the variations in pollutant loads entrained in stormwater runoff from urban catchments. However, build-up and wash-off predictions from stormwater quality models do not adequately represent such variations due to poor characterisation of the variability of these processes in mathematical models. The changes to the mathematical form of current models with the incorporation of process variability, facilitates accounting for process uncertainty without significantly affecting the model prediction performance. Moreover, the investigation of uncertainty propagation from build-up to wash-off confirmed that uncertainty in build-up process significantly influences wash-off process uncertainty. Specifically, the behaviour of particles <150 μm during build-up primarily influences uncertainty propagation, resulting in appreciable variations in the pollutant load and composition during a wash-off event. PMID:26840516

  15. The clinical use of PET with 11C-acetate

    PubMed Central

    Grassi, Ilaria; Nanni, Cristina; Allegri, Vincenzo; Morigi, Joshua James; Montini, Gian Carlo; Castellucci, Paolo; Fanti, Stefano

    2012-01-01

    The aim of this review is to evaluate clinical applications of 11C-acetate positron emission tomography (PET). Acetate is quickly metabolized into acetyl-CoA in human cells. In this form it can either enter into the tricarboxylic acid cycle, thus producing energy, as happens in the myocardium, or participate in cell membrane lipid synthesis, as happens in tumor cells. 11C-acetate PET was originally employed in cardiology, to study myocardial oxygen metabolism. More recently it has also been used to evaluate myocardial perfusion, as well as in oncology. The first studies of 11C-acetate focused on its use in prostate cancer. Subsequently, 11C-acetate was studied in other urological malignancies, as well as renal cell carcinoma and bladder cancer. Well differentiated hepatocellular carcinoma represents an 18F-fluoro-deoxyglucose (18F-FDG) PET pitfall, so many authors have proposed to use 11C-acetate in addition to 18F-FDG in studying this tumor. 11C-acetate PET has also been used in other malignancies, such as brain tumors and lung carcinoma. Some authors reported a few cases in which 11C-acetate PET incidentally found multiple myeloma or rare tumors, such as thymoma, multicentric angiomyolipoma of the kidney and cerebellopontine angle schwannoma. Lastly, 11C-acetate PET was also employed in a differential diagnosis case between glioma and encephalitis. The numerous studies on 11C-acetate have demonstrated that it can be used in cardiology and oncology with no contraindications apart from pregnancy and the necessity of a rapid scan. Despite its limited availability, this tracer can surely be considered to be a promising one, because of its versatility and capacity to even detect non 18F-FDG-avid neoplasm, such as differentiated lung cancer or hepatocellular carcinoma. PMID:23133801

  16. Positron annihilation spectroscopy of biological tissue in 11C irradiation

    NASA Astrophysics Data System (ADS)

    Sakurai, Hiroshi; Itoh, Fumitake; Hirano, Yoshiyuki; Nitta, Munetaka; Suzuki, Kosuke; Kato, Daisuke; Yoshida, Eiji; Nishikido, Fumihiko; Wakizaka, Hidekatsu; Kanai, Tatsuaki; Yamaya, Taiga

    2014-11-01

    Positron annihilation spectroscopy (PAS) spectra of biological tissue in 11C irradiation are reported and spatial resolution coefficient of positron emission tomography (PET) obtained from the PAS spectrum is discussed for 11C irradiation. A PAS spectrum of the biological tissue with water is the same as that of the water pool phantom in 11C irradiation. However, a PAS spectrum of the biological tissue with less water differs from that of the water pool phantom. The PET spatial resolution coefficient depends on the kind of biological tissue. However, the PET spatial resolution coefficient, 0.00243  ±  0.00014, can be used as a common value of maximum limit.

  17. Synthesis of [11C]Bexarotene by Cu-Mediated [11C]Carbon Dioxide Fixation and Preliminary PET Imaging

    PubMed Central

    2014-01-01

    Bexarotene (Targretin) is a retinoid X receptor (RXR) agonist that has applications for treatment of T cell lymphoma and proposed mechanisms of action in Alzheimer’s disease that have been the subject of recent controversy. Carbon-11 labeled bexarotene ([11C-carbonyl]4-[1-(3,5,5,8,8-pentamethyltetralin-2-yl)ethenyl]benzoic acid) was synthesized using a Cu-mediated cross-coupling reaction employing an arylboronate precursor 1 and [11C]carbon dioxide under atmospheric pressure in 15 ± 2% uncorrected radiochemical yield (n = 3), based on [11C]CO2. Judicious choice of solvents, catalysts, and additives, as well as precursor concentration and purity of [11C]CO2, enabled the preparation of this 11C-labeled carboxylic acid. Formulated [11C]bexarotene was isolated (>37 mCi) with >99% radiochemical purity in 32 min. Preliminary positron emission tomography–magnetic resonance imaging revealed rapid brain uptake in nonhuman primate in the first 75 s following intravenous administration of the radiotracer (specific activity >0.3 Ci/μmol at time of injection), followed by slow clearance (Δ = −43%) over 60 min. Modest uptake (SUVmax = 0.8) was observed in whole brain and regions with high RXR expression. PMID:24944741

  18. New interplanetary proton fluence model

    NASA Technical Reports Server (NTRS)

    Feynman, Joan; Armstrong, T. P.; Dao-Gibner, L.; Silverman, S.

    1990-01-01

    A new predictive engineering model for the interplanetary fluence of protons with above 10 MeV and above 30 MeV is described. The data set used is a combination of observations made from the earth's surface and from above the atmosphere between 1956 and 1963 and observations made from spacecraft in the vicinity of earth between 1963 and 1985. The data cover a time period three times as long as the period used in earlier models. With the use of this data set the distinction between 'ordinary proton events' and 'anomalously large events' made in earlier work disappears. This permitted the use of statistical analysis methods developed for 'ordinary events' on the entire data set. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. At energies above 30 MeV, the old and new models agree. In contrast to earlier models, the results do not depend critically on the fluence from any one event and are independent of sunspot number. Mission probability curves derived from the fluence distribution are presented.

  19. Influence of hydrogen fluence on surface blistering of H and He co-implanted Ge

    NASA Astrophysics Data System (ADS)

    Dai, Jiayun; Xue, Zhongying; Zhang, Miao; Wei, Xing; Wang, Gang; Di, Zengfeng

    2016-02-01

    The effect of hydrogen fluence on surface blistering of H and He co-implanted Ge is investigated using atom force microscope, X-ray diffraction and transmission electron microscopy. With a fixed He, we find that for 1 × 1016 cm-2 H implantation fluence, only a few small dome-shaped blisters appear, for 3 × 1016 cm-2 H implantation fluence, large blisters as well as craters are formed, while for 5 × 1016 cm-2 H implantation fluence, no blisters can be observed. The strain evolution and platelet forming tendency are found to be relevant for the different blistering phenomenon. The weak blistering phenomenon for 1 × 1016 cm-2 H implantation fluence may be attributed to less "free" H for the building up of internal pressure of platelets and the sustained growth of platelets. While the absence of blistering phenomenon for 5 × 1016 cm-2 H implantation fluence is likely due to the retarded relief of the decreased uniform compressive stress throughout the damage region.

  20. Improved Automated Radiosynthesis of [11C]PBR28

    PubMed Central

    Solingapuram Sai, Kiran Kumar; Gage, Don; Nader, Mike; Mach, Robert H.; Mintz, Akiva

    2015-01-01

    Microglial activation is commonly identified by elevated levels of the 18 kDa translocator protein (TSPO) in response to several inflammatory processes. [11C]PBR28 is one of the most promising PET tracers to image TSPO in both human and non-human primates. In this study, we optimized the radiolabeling procedure of [11C]PBR28 for higher radiochemical yield, radiochemical purity, and specific activity, which can be easily translated to any automated module for clinical trials. Time-activity curves (TACs) derived from the dynamic PET imaging of male rhesus monkey brains demonstrated that [11C]PBR28 had suitable kinetics with radiotracer accumulation observed in the caudate, putamen, cerebellum, and frontal cortex region. PMID:26839827

  1. Preclinical PET Neuroimaging of [11C]Bexarotene.

    PubMed

    Rotstein, Benjamin H; Placzek, Michael S; Krishnan, Hema S; Pekošak, Aleksandra; Collier, Thomas Lee; Wang, Changning; Liang, Steven H; Burstein, Ethan S; Hooker, Jacob M; Vasdev, Neil

    2016-01-01

    Activation of retinoid X receptors (RXRs) has been proposed as a therapeutic mechanism for the treatment of neurodegeneration, including Alzheimer's and Parkinson's diseases. We previously reported radiolabeling of a Food and Drug Administration-approved RXR agonist, bexarotene, by copper-mediated [(11)C]CO2 fixation and preliminary positron emission tomography (PET) neuroimaging that demonstrated brain permeability in nonhuman primate with regional binding distribution consistent with RXRs. In this study, the brain uptake and saturability of [(11)C]bexarotene were studied in rats and nonhuman primates by PET imaging under baseline and greater target occupancy conditions. [(11)C]Bexarotene displays a high proportion of nonsaturable uptake in the brain and is unsuitable for RXR occupancy measurements in the central nervous system. PMID:27553293

  2. Myocradial extraction of 1-[{sup 11}C] betamethylheptadecanoic acid

    SciTech Connect

    Elmaleh, D.R.; Livni, E.; Alpert, N.M.

    1994-03-01

    Betamethylheptadecanoic acid (BMHA) is a branched chain fatty acid analog that is transported into myocardial cells by the same long chain fatty acid carrier protein mechanism as natural fatty acids, but cannot be completely catabolzied and accumulates in the tissue. Thus, {sup 11}C-labeled BMHA is a useful tracer for the noninvasive evaluation of myocardial fatty acid utilization by positron emission tomography (PET). As a prelude to PET studies, the metabolism of BMHA was studied by classical techniques. The authors measured the net extraction fraction (E{sub n}) of 1-[{sup 11}C]-beta-R,S-methylheptadecanoic acid (1-[{sup 11}C]BMHA) and compared it to that of natural fatty acids in dogs, using arterial/venous measurements and a mathematical model. Two groups of conditioned dogs were studied. In the first group, measurements were made under fasting (normal control) conditions and in the second group, measurements were made during glucose and insulin infusion. Myocardial blood flow, and the extraction/utilization of other substrates (glucose, oxygen and lactate) were also measured. For natural fatty acids in the basal state, E{sub n}(FA) was 0.335. After glucose/insulin infusion, this value decreased to 0.195. The 1-[{sup 11}C]BMHA showed a similar decrease in E{sub n}(BMHA) from 0.220 in the control group to 0.100 in the group treated with glucose/insulin infusion. Preliminary PET studies with 1-[{sup 11}C]BMHA verified the validity of performing these measurements noninvasively. The results of these studies indicate that rates of fatty acid metabolism in the myocardium can be determined from steady-state concentrations of 1-[{sup 11}C]BMHA. 36 refs., 6 figs., 4 tabs.

  3. The needs for prediction and real-time monitoring for the flare build-up study

    NASA Technical Reports Server (NTRS)

    Svestka, Z.

    1979-01-01

    Similarities between plasma instabilities occurring in the magnetospheric tail and in active regions on the Sun are discussed. Intense observations of the flare build-up processes on the Sun planned for May and June 1980 as a part of the Solar Maximum Year are described.

  4. Implications for flare build-up and heating from observations made by OSO-7

    NASA Technical Reports Server (NTRS)

    Neupert, W. M.

    1975-01-01

    The evolution of the EUV and soft X-ray emission in the event on January 19, 1972 are discussed in terms of the slow (passive) and fast (active) phases of flare evolution that were previously discussed. The implications are summarized for a flare build-up model which was derived-from these observations.

  5. Radiosynthesis and preliminary PET evaluation of glycogen synthase kinase 3β (GSK-3β) inhibitors containing [(11)C]methylsulfanyl, [(11)C]methylsulfinyl or [(11)C]methylsulfonyl groups.

    PubMed

    Kumata, Katsushi; Yui, Joji; Xie, Lin; Zhang, Yiding; Nengaki, Nobuki; Fujinaga, Masayuki; Yamasaki, Tomoteru; Shimoda, Yoko; Zhang, Ming-Rong

    2015-08-15

    Three compounds 1-3 containing methyl-sufanyl, sufinyl, or sulfonyl groups are strong inhibitors of glycogen synthase kinase 3β (GSK-3β), an enzyme associated with Alzheimer's disease. We labeled 1-3 with (11)C for a positron emission tomography (PET) brain imaging study. A novel thiophenol precursor 4 for radiosynthesis was prepared by reacting sulfoxide 2 with trifluoroacetic anhydride. [(11)C]1 was synthesized by reacting 4 with [(11)C]methyl iodide in 52 ± 5% radiochemical yield (n = 5, based on [(11)C]CO2, corrected for decay). Oxidation of [(11)C]1 with Oxone® produced [(11)C]2 and [(11)C]3, respectively. PET with [(11)C]1 and [(11)C]3 showed 2 fold higher brain uptake of radioactivity in a mouse model of cold water stress in which GSK-3β expression was increased, than in the controls. PMID:26067173

  6. Depositional evolution of lower permian Palaeoaplysina build-ups, Kapp duner formation, Bjørnøya, Arctic Norway

    NASA Astrophysics Data System (ADS)

    Stemmerik, L.; Larson, P. A.; Larssen, G. B.; Mørk, A.; Simonsen, B. T.

    1994-09-01

    The Lower Permian Kapp Duner Formation on Bjørnøya includes an approximately 45 m thick Palaeoaplysina build-up complex. This complex is composed of stacked cycles of thin (0-1 m thick) restricted shelf mudstones and thicker (< 10 m thick) build-ups of Palaeoaplysina wackestone to boundstone capped by subaerial exposure surfaces. In the lower part of the complex, the build-ups are tabular and laterally more widespread than the lenticular build-ups found in the upper part of the complex. The depositional cycles most likely formed in response to fourth-order glacio-eustatic fluctuations in sea level, while the history of the build-up complex is controlled by longer-term, third-order fluctuations in relative sea level. The position of the build-up complex is structurally controlled.

  7. Particle Test Fluence: What's the Right Number?

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.

    2016-01-01

    While we have been utilizing standard fluence levels such as those listed in the JESD57 document, we have begun revisiting what an appropriate test fluence is when it comes to qualifying a device for single events. Instead of a fixed fluence level or until a specific number of events occurs, a different thought process is required.

  8. Monitoring the stress build-up in dental cements: a novel optical characterization technique

    NASA Astrophysics Data System (ADS)

    Ottevaere, Heidi; Tabak, M.; Bartholomees, F.; de Wilde, Willy P.; Veretennicoff, Irina P.; Thienpont, Hugo

    2001-01-01

    It is well known that during the curing of dental cements, polymerization shrinkage induces unacceptable stresses, which can result into cracks and an over-sensitivity of the teeth. We demonstrate that polarimetric optical fiber sensors can be used to characterize this shrinkage quantitatively. To determine the time evolution and the amount of shrinkage we embed a highly birefringent optical fiber in the dental cement and analyze the change in optical polarization at its output. This change is a measure for the dynamic stress-build up. We also demonstrate the repeatability of our characterization method for these cements. Moreover we given indications that this technique allows for in- vivo monitoring of the stress build-up dynamics between dentine and porcelain facings. This may bring durable all-ceramic restorations closer to reality. In this paper we present the principle of this original optical fiber sensor, its practical implementation and the experimental results we obtained for this application.

  9. Build-up material requirements in clinical dosimetry during total body irradiation treatments

    PubMed Central

    Butson, Martin; Pope, Dane; Haque, Mamoon; Chen, Tom; Song, Guangli; Whitaker, May

    2016-01-01

    Total body irradiation (TBI) treatments are mainly used in a preparative regimen for hematopoietic stem cell (or bone marrow) transplantation. Our standard clinical regimen is a 12 Gy/6 fraction bi-daily technique using 6MV X-rays at a large extended source to surface distance (SSD). This work investigates and quantifies the dose build-up characteristics and thus the requirements for bolus used for in vivo dosimetry for TBI applications. Percentage dose build-up characteristics of photon beams have been investigated at large extended SSDs using ionization chambers and Gafchromic film. Open field measurements at different field sizes and with differing scatter conditions such as the introduction of standard Perspex scattering plates at different distances to the measurement point were made in an effort to determine the required bolus/build-up material required for accurate determination of applied dose. Percentage surface dose values measured for open fields at 300 cm SSD were found to range from 20% up to 65.5% for fields 5 cm × 5 cm to 40 cm × 40 cm, respectively. With the introduction of 1 cm Perspex scattering plates used in TBI treatments, the surface dose values increased up to 83–90% (93–97% at 1 mm depth), depending on the position of the Perspex scattering plate compared to the measurement point. Our work showed that at least 5 mm water equivalent bolus/scatter material should be placed over the EBT3 film for accurate dose assessment for TBI treatments. Results also show that a small but measurable decrease in measured dose occurred with 5 mm water equivalent thick bolus material of areas '3 cm2. As such, we recommend that 3 cm × 3 cm × 5 mm bolus build-up is the smallest size that should be placed over EBT3 Gafchromic film when used for accurate in vivo dosimetry for TBI applications. PMID:27217628

  10. Build-up material requirements in clinical dosimetry during total body irradiation treatments.

    PubMed

    Butson, Martin; Pope, Dane; Haque, Mamoon; Chen, Tom; Song, Guangli; Whitaker, May

    2016-01-01

    Total body irradiation (TBI) treatments are mainly used in a preparative regimen for hematopoietic stem cell (or bone marrow) transplantation. Our standard clinical regimen is a 12 Gy/6 fraction bi-daily technique using 6MV X-rays at a large extended source to surface distance (SSD). This work investigates and quantifies the dose build-up characteristics and thus the requirements for bolus used for in vivo dosimetry for TBI applications. Percentage dose build-up characteristics of photon beams have been investigated at large extended SSDs using ionization chambers and Gafchromic film. Open field measurements at different field sizes and with differing scatter conditions such as the introduction of standard Perspex scattering plates at different distances to the measurement point were made in an effort to determine the required bolus/build-up material required for accurate determination of applied dose. Percentage surface dose values measured for open fields at 300 cm SSD were found to range from 20% up to 65.5% for fields 5 cm × 5 cm to 40 cm × 40 cm, respectively. With the introduction of 1 cm Perspex scattering plates used in TBI treatments, the surface dose values increased up to 83-90% (93-97% at 1 mm depth), depending on the position of the Perspex scattering plate compared to the measurement point. Our work showed that at least 5 mm water equivalent bolus/scatter material should be placed over the EBT3 film for accurate dose assessment for TBI treatments. Results also show that a small but measurable decrease in measured dose occurred with 5 mm water equivalent thick bolus material of areas '3 cm(2). As such, we recommend that 3 cm × 3 cm × 5 mm bolus build-up is the smallest size that should be placed over EBT3 Gafchromic film when used for accurate in vivo dosimetry for TBI applications. PMID:27217628

  11. Build-up dynamics of heavy metals deposited on impermeable urban surfaces.

    PubMed

    Wicke, D; Cochrane, T A; O'Sullivan, A

    2012-12-30

    A method using thin boards (3 cm thick, 0.56 m(2)) comprising different paving materials typically used in urban environments (2 asphalt types and concrete) was employed to specifically investigate air-borne deposition dynamics of TSS, zinc, copper and lead. Boards were exposed at an urban car park near vehicular traffic to determine the rate of contaminant build-up over a 13-day dry period. Concentration profiles from simulated rainfall wash-off were used to determine contaminant yields at different antecedent dry days. Maximum contaminant yields after 13 days of exposure were 2.7 kg ha(-1) for TSS, 35 g ha(-1) zinc, 2.3 g ha(-1) copper and 0.4 g ha(-1) lead. Accumulation of all contaminants increased over the first week and levelled off thereafter, supporting theoretical assumptions that contaminant accumulation on impervious surfaces asymptotically approaches a maximum. Comparison of different surface types showed approximately four times higher zinc concentrations in runoff from asphalt surfaces and two times higher TSS concentrations in runoff from concrete, which is attributed to different physical and chemical compositions of the pavement types. Contaminant build-up and wash-off behaviours were modelled using exponential and saturation functions commonly applied in the US EPA's Stormwater Management Model (SWMM) showing good correlation between measured and modelled concentrations. Maximum build-up, half-saturation time, build-up rate constants and wash-off coefficients, necessary for stormwater contaminant modelling, were determined for the four contaminants studied. These parameters are required to model contaminant concentrations in urban runoff assisting in stormwater management decisions. PMID:23044158

  12. Processing ultrasonic inspection data from multiple scan patterns for turbine rotor weld build-up evaluations

    SciTech Connect

    Guan, Xuefei; Zhou, S. Kevin; Rasselkorde, El Mahjoub; Abbasi, Waheed

    2015-03-31

    The study presents a data processing methodology for weld build-up using multiple scan patterns. To achieve an overall high probability of detection for flaws with different orientations, an inspection procedure with three different scan patterns is proposed. The three scan patterns are radial-tangential longitude wave pattern, axial-radial longitude wave pattern, and tangential shear wave pattern. Scientific fusion of the inspection data is implemented using volume reconstruction techniques. The idea is to perform spatial domain forward data mapping for all sampling points. A conservative scheme is employed to handle the case that multiple sampling points are mapped to one grid location. The scheme assigns the maximum value for the grid location to retain the largest equivalent reflector size for the location. The methodology is demonstrated and validated using a realistic ring of weld build-up. Tungsten balls and bars are embedded to the weld build-up during manufacturing process to represent natural flaws. Flat bottomed holes and side drilled holes are installed as artificial flaws. Automatic flaw identification and extraction are demonstrated. Results indicate the inspection procedure with multiple scan patterns can identify all the artificial and natural flaws.

  13. Characterizing heavy metal build-up on urban road surfaces: implication for stormwater reuse.

    PubMed

    Liu, An; Liu, Liang; Li, Dunzhu; Guan, Yuntao

    2015-05-15

    Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a "fit-for-purpose" road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. PMID:25687783

  14. On spatial stabilization of dielectric barrier discharge microfilaments by residual heat build-up in air

    NASA Astrophysics Data System (ADS)

    Ráhel, Jozef; Szalay, Zsolt; Čech, Jan; Morávek, Tomás

    2016-04-01

    Microfilaments of dielectric barrier discharge are known for their multiple re-appearance at the same spot on dielectrics. This effect of localized re-appearance is driven by residual excited species and ions, surface charge deposited on the dielectric and the local temperature build-up resulting in the local increase of reduced electric field E/ΔN. To assess the magnitude of the latter, the breakdown voltage vs. temperature up to 180 °C was carefully measured at coplanar DBD and used as an input into the numerical simulation of heat build-up by the train of discharge pulses. An average reduction of breakdown voltage was found to be 20 V/K. The model predicted a quasi-stable microfilament temperature into which the thermal build-up rapidly converges. Its magnitude agreed well with the reported rotational temperature of similar electrode configuration. The impact of quasi-stable temperature on microfilament formation dynamics is further discussed. Contribution to the Topical Issue "Recent Breakthroughs in Microplasma Science and Technology", edited by Kurt Becker, Jose Lopez, David Staack, Klaus-Dieter Weltmann and Wei Dong Zhu.

  15. Building Up of the Plastid Transcriptional Machinery during Germination and Early Plant Development1

    PubMed Central

    Demarsy, Emilie; Courtois, Florence; Azevedo, Jacinthe; Buhot, Laurence; Lerbs-Mache, Silva

    2006-01-01

    The plastid genome is transcribed by three different RNA polymerases, one is called plastid-encoded RNA polymerase (PEP) and two are called nucleus-encoded RNA polymerases (NEPs). PEP transcribes preferentially photosynthesis-related genes in mature chloroplasts while NEP transcribes preferentially housekeeping genes during early phases of plant development, and it was generally thought that during plastid differentiation the building up of the NEP transcription system precedes the building up of the PEP transcription system. We have now analyzed in detail the establishment of the two different transcription systems, NEP and PEP, during germination and early seedling development on the mRNA and protein level. Experiments have been performed with two different plant species, Arabidopsis (Arabidopsis thaliana) and spinach (Spinacia oleracea). Results show that the building up of the two different transcription systems is different in the two species. However, in both species NEP as well as PEP are already present in seeds, and results using Tagetin as a specific inhibitor of PEP activity demonstrate that PEP is important for efficient germination, i.e. PEP is already active in not yet photosynthetically active seed plastids. PMID:16963522

  16. Optimal Thermo-Structural Analysis for High Density Package Mounting on Build-up Board

    NASA Astrophysics Data System (ADS)

    Nakanishi, Tohru; Hase, Tomohiro

    The importance of the high density packaging technology and mounting technology on the printed wiring build-up board has been increased for the consumer electric products. On the other hand, the chance to use the build-up boards for mounting the high density packages has been increased. However, the understanding that the reliability of the solder connection depends on the structure of the package, the motherboard, and the material properties, is not very high. In this paper, the reliability for high density packaging, mounted on the build-up board, is assessed. The compact numerical analysis model for the reliability assessment is suggested and the most reliable packaging design with optimizing each of the parameters is reported. For introduction to the reliability assessment of the FCA attachment, ceramic and silicon are compared as the inter-poser with the parameter of the solder height. The verification of the numerical analysis results using tests on the actual hardware is also shown. And the established numerical analysis model is applied to the study of influence of the copper balance between the front side and the back side copper layers.

  17. The influence of target torque and torque build-up time on physical stress in right angle nutrunner operation.

    PubMed

    Oh, S A; Radwin, R G

    1998-02-01

    This study used a computer-controlled electric right angle nutrunner to investigate the relative effects of different power hand tool and process parameters on operator muscular exertions, handle stability and subjective ratings of perceived exertion. Target torque (25, 40 and 55 Nm), torque build-up time (35, 150, 300, 500 and 900 ms), and workstation orientation (horizontal and vertical) were studied. Dependent variables included EMG activity of the finger flexors, biceps, and triceps, handle velocity and displacement, work done on the tool-hand system and power involved in doing work, subjective ratings of perceived exertion, and task acceptance. Six inexperienced subjects (three females and three males) participated. Ten replications were performed for each combination of experimental conditions. The consequences of increasing the torque reaction force were greater handle instability and perceived exertion. The effect of torque build-up time on handle kinematics, muscular activity and perceived exertion was not monotonic. Among five build-up times tested, the hand was most unstable (greater peak handle velocity and power against the operator) for a 150 ms build-up time. Greater peak handle displacement, total work against the operator and average EMG were observed for 150 and 300 ms build-up times than for other build-up time conditions. Integrated EMG and EMG latency significantly increased as build-up time increased. Average EMG latency between the onset of EMG burst and the onset of torque build-up was 40 ms for a 35 ms build-up time and 330 ms for a 900 ms build-up time. Subjective ratings of perceived exertion were the least when torque build-up time was 35 ms, however greater peak torque variance was associated with this condition. PMID:9494431

  18. (11)C-Methionine uptake in secondary brain epilepsy.

    PubMed

    Lopci, E; Bello, L; Chiti, A

    2014-01-01

    Carbon-11 methionine ((11)C-Methionine) is a radio-labeled amino acid currently utilized in Positron Emission Tomography (PET) for imaging primary and metastatic brain tumors. Its clinical use relies mostly on oncologic applications, but the tracer has the potential to investigate other non-malignant conditions. So far, very limited evidence concerns the use of (11)C-Methionine in patients suffering from seizure; however, the tracer can find a proper utilization in this setting especially as a diagnostic complement to (18)F-Fluorodeoxyglucose ((18)F-FDG). Herein we report the case of a 57-year-old patient presenting with epileptic crises secondary to a brain metastasis from bladder carcinoma, who was investigated in our institution with (11)C-Methionine PET. The scan documented the disease recurrence in the left parietal lobe associated with a diffused tracer uptake in the surrounding cerebral circumvolutions, derived from the comitial status. After surgical removal of the metastatic lesion, the patient experienced a complete recovery of symptoms and no further onset of secondary seizure. PMID:24630372

  19. Study of the 11C(p,gamma) reaction via the indirect d(11C,12N)ntransfer reaction

    SciTech Connect

    Lee, Dongwon; Powell, James; Perajarvi, Kari; Guo, Fanqing; Moltz, Dennis; Cerny, Joseph

    2008-01-07

    The {sup 11}C(p,{gamma}){sup 12}N reaction is expected to be an important branch point in supermassive low-metallicity stars because it could produce CNO seed nuclei before the traditional triple-alpha process turns on. In the present work, the d({sup 11}C, {sup 12}N)n transfer reaction was employed to evaluate this reaction using a radioactive ion beam of 150 MeV {sup 11}C with 6 x 10{sup 5} ions/s on target from the BEARS project at the 88-inch cyclotron at Lawrence Berkeley National Laboratory. Excellent agreement was obtained between the experimental cross sections ({theta}{sub c.m.} = 10.9{sup o} to 71.5{sup o}) and DWBA calculations. The asymptotic normalization coefficient was deduced to be (C{sub eff}{sup 12N}){sup 2} = (C{sub p1/2}{sup 12N}){sup 2} + (C{sub p3/2}{sup 12N}){sup 2} = 1.83 {+-} 0.27 fm{sup -1}.

  20. Fracture resistance of five pin-retained core build-up materials on teeth with and without extracoronal preparation.

    PubMed

    Burke, F J; Shaglouf, A G; Combe, E C; Wilson, N H

    2000-01-01

    Core build-ups should provide satisfactory strength and resistance to fracture both before and after crown preparation. This paper examines the resistance to fracture of core build-ups in different materials and the fracture resistance of core build-ups when these have been reduced for full crown preparation. Standardized core build-ups were made on groups of extracted molar teeth of similar size, with 10 teeth per group. Three resin-composite (prisma APH: Dentsply, Weybridge, UK; Ti-Core, Essential Dental Systems, NJ, US and Coradent, Vivadent, Liechtenstein), one cermet (Ketac-Silver, ESPE GmbH, Seefeld, Germany) and one amalgam material (Duralloy, Degussa Ltd, Cheshire, UK). These specimens were subjected to compressive force on a universal testing machine and the force at fracture noted. Standardized full crown preparations were made on a further five groups of core build-up specimens using the same materials as above. These prepared specimens were subjected to compressive force on a universal testing machine and the force to fracture noted. The results indicated that amalgam core build-ups demonstrated higher fracture resistance than the other materials examined. There was a general decrease in the fracture strength of the specimens following crown preparation, with the teeth restored with the amalgam core build-ups showing a greater percentage reduction in fracture strength than the other materials tested. Prepared core build-ups in a hybrid composite material provided the highest fracture resistance. The cermet material used provided the lowest resistance to fracture in both the core build-up and crown preparation specimens. In terms of fracture resistance, no advantage was apparent in using the two composite materials designated as being specifically appropriate for core build-ups. PMID:11203847

  1. Uncertainty analysis of pollutant build-up modelling based on a Bayesian weighted least squares approach.

    PubMed

    Haddad, Khaled; Egodawatta, Prasanna; Rahman, Ataur; Goonetilleke, Ashantha

    2013-04-01

    Reliable pollutant build-up prediction plays a critical role in the accuracy of urban stormwater quality modelling outcomes. However, water quality data collection is resource demanding compared to streamflow data monitoring, where a greater quantity of data is generally available. Consequently, available water quality datasets span only relatively short time scales unlike water quantity data. Therefore, the ability to take due consideration of the variability associated with pollutant processes and natural phenomena is constrained. This in turn gives rise to uncertainty in the modelling outcomes as research has shown that pollutant loadings on catchment surfaces and rainfall within an area can vary considerably over space and time scales. Therefore, the assessment of model uncertainty is an essential element of informed decision making in urban stormwater management. This paper presents the application of a range of regression approaches such as ordinary least squares regression, weighted least squares regression and Bayesian weighted least squares regression for the estimation of uncertainty associated with pollutant build-up prediction using limited datasets. The study outcomes confirmed that the use of ordinary least squares regression with fixed model inputs and limited observational data may not provide realistic estimates. The stochastic nature of the dependent and independent variables need to be taken into consideration in pollutant build-up prediction. It was found that the use of the Bayesian approach along with the Monte Carlo simulation technique provides a powerful tool, which attempts to make the best use of the available knowledge in prediction and thereby presents a practical solution to counteract the limitations which are otherwise imposed on water quality modelling. PMID:23454702

  2. Regional Brain [11C]carfentanil Binding Following Tobacco Smoking

    PubMed Central

    Domino, Edward F; Hirasawa-Fujita, Mika; Ni, Lisong; Guthrie, Sally K; Zubieta, Jon Kar

    2015-01-01

    Objective To determine if overnight tobacco abstinent carriers of the AG or GG (*G) vs. the AA variant of the human mu opioid receptor (OPRM1) A118G polymorphism (rs1799971) differ in [11C]carfentanil binding after tobacco smoking. Methods Twenty healthy American male smokers who abstained from tobacco overnight were genotyped and completed positron emission tomography (PET) scans with the mu opioid receptor agonist, [11C]carfentanil. They smoked deniconized (denic) and average nicotine (avnic) cigarettes during the PET scans. Results Smoking avnic cigarette decreased the binding potential (BPND) of [11C]carfentanil in the right medial prefrontal cortex (mPfc; 6,56,18), left anterior medial prefrontal cortex (amPfc; −2,46,44), right ventral striatum (vStr; 16, 3, −10), left insula (Ins; −42,10, −12), right hippocampus (Hippo; 18, −6, −14) and left cerebellum (Cbl; −10, −88, −34), and increased the BPND in left amygdala (Amy; −20,0, −22), left putamen (Put; −22, 10, −6) and left nucleus accumbens (NAcc; −10,12, −8). In the AA allele carriers, avnic cigarette smoking significantly changed the BPND compared to after denic smoking in most brain areas listed above. However in the *G carriers the significant BPND changes were confirmed in only amPfc and vStr. Free mu opioid receptor availability was significantly less in the *G than the AA carriers in the Amy and NAcc. Conclusion The present study demonstrates BPND changes induced by avnic smoking in OPRM1 *G carriers were blunted compared to the AA carriers. Also *G smokers had less free mu opioid receptor availability in Amy and NAcc. PMID:25598501

  3. Simulations of electron cloud build-up and saturation in the APS

    SciTech Connect

    Harkay, K.C.; Rosenberg, R.A.; Furman, M.A.; Pivi, M.

    2002-06-19

    In studies with positron beams in the Advanced Photon Source, a dramatic amplification was observed in the electron cloud for certain bunch current and bunch spacings. In modeling presented previously, we found qualitative agreement with the observed beam-induced multipacting condition, provided reasonable values were chosen for the secondary electron yield parameters, including the energy distribution. In this paper, we model and discuss the build-up and saturation process observed over long bunch trains at the resonance condition. Understanding this saturation mechanism in more detail may have implications for predicting electron cloud amplification, multipacting, and instabilities in future rings.

  4. 18F-Labelled Intermediates for Radiosynthesis by Modular Build-Up Reactions: Newer Developments

    PubMed Central

    Ermert, Johannes

    2014-01-01

    This brief review gives an overview of newer developments in 18F-chemistry with the focus on small 18F-labelled molecules as intermediates for modular build-up syntheses. The short half-life (<2 h) of the radionuclide requires efficient syntheses of these intermediates considering that multistep syntheses are often time consuming and characterized by a loss of yield in each reaction step. Recent examples of improved synthesis of 18F-labelled intermediates show new possibilities for no-carrier-added ring-fluorinated arenes, novel intermediates for tri[18F]fluoromethylation reactions, and 18F-fluorovinylation methods. PMID:25343144

  5. Cryogenic molecular separation system for radioactive 11C ion acceleration

    NASA Astrophysics Data System (ADS)

    Katagiri, K.; Noda, A.; Suzuki, K.; Nagatsu, K.; Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ramzdorf, A. Yu.; Nakao, M.; Hojo, S.; Wakui, T.; Noda, K.

    2015-12-01

    A 11C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. In the ISOL system, 11CH4 molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive 12CH4 gases, which can simulate the chemical characteristics of 11CH4 gases. We investigated the separation of CH4 molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH4. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system.

  6. Blind Via Hole in Multi-layer AFRP Printed Wiring Boards by Build-Up Process

    NASA Astrophysics Data System (ADS)

    Hirogaki, Toshiki; Nakagawa, Heisaburo; Aoyama, Eiichi; Katayama, Tsutao; Inoue, Hisahiro

    In the printed wiring board manufacturing sector, methods have been developed to improve the circuit packaging density. The multi-layer printed wiring board manufacturing process is receiving particular attention. In the current manufacture of these boards, the method frequently used is to laminate the core with insulating resin, namely a build-up process. Etching is generally used to form the holes connecting the circuits of these boards. However, a problem has emerged in that the strength of the substrate decreases due to the insulating resin part as the multi-layers are progressively formed. Thus, it becomes necessary to use FRP for the insulation layer part. Since it is very difficult to etch composites, lasers have been proposed for a new way to drill holes in such materials. By appropriate adjustment of the laser penetration energy, the holes are drilled only in the insulation part, and a technique is proposed to stop the holes using the copper foil forming the circuit. AFRP has been considered a suitable FRP for such laser processing. In the present study, attempts were made to experimentally produce multi-layer boards using AFRP and GFRP for the build-up insulation layer, and the characteristics of blind via holes drilling with a small power laser were investigated.

  7. Build-up of toxic metals on the impervious surfaces of a commercial seaport.

    PubMed

    Ziyath, Abdul M; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2016-05-01

    In the context of increasing threats to the sensitive marine ecosystem by toxic metals, this study investigated the metal build-up on impervious surfaces specific to commercial seaports. The knowledge generated from this study will contribute to managing toxic metal pollution of the marine ecosystem. The study found that inter-modal operations and main access roadway had the highest loads followed by container storage and vehicle marshalling sites, while the quay line and short term storage areas had the lowest. Additionally, it was found that Cr, Al, Pb, Cu and Zn were predominantly attached to solids, while significant amount of Cu, Pb and Zn were found as nutrient complexes. As such, treatment options based on solids retention can be effective for some metal species, while ineffective for other species. Furthermore, Cu and Zn are more likely to become bioavailable in seawater due to their strong association with nutrients. Mathematical models to replicate the metal build-up process were also developed using experimental design approach and partial least squares regression. The models for Cr and Pb were found to be reliable, while those for Al, Zn and Cu were relatively less reliable, but could be employed for preliminary investigations. PMID:26866754

  8. Investigation of Pectin/Chitosan Multilayers Build-up on Corona Charged Polylactide Substrates

    NASA Astrophysics Data System (ADS)

    Yovcheva, T. A.; Marudova, M. G.; Viraneva, A. P.; Gencheva, E. A.; Mekishev, G. A.; Sainov, S. H.

    2010-01-01

    The aim of the present research is to investigate the formation and stability of pectin/chitosan multilayer films on preliminary corona charged polylactide substrate with different polarity. For this purpose two different multilayer structures with alternative ordering of polycation and polyanion layers were prepared. Layer-by-layer (LbL) deposition technique was used for multilayer build-up. The FT-IR transmittance spectra of the substrates with multilayers indicated of the presence of pectin and chitosan. The intensity of the typical bands was found to increase with increasing of the number of the deposited layers. The stability and physico-chemical properties of the multilayer structures were investigated by determination of surface refractive index and swelling behaviour. Multilayers are stable enough in distilled water and their equilibrium degree of swelling increases with the increase of build-up layers. This relation is correlated with the increased amount of hydrophilic biopolymers. It was found out that chitosan/pectin multilayers buil-up on negatively charged substrate consist of higher amount of polyelectrolytes and are more stable in distilled water.

  9. Optical fiber sensors and their application in monitoring stress build-up in dental resin cements

    NASA Astrophysics Data System (ADS)

    Ottevaere, H.; Tabak, M.; Fernandez Fernandez, A.; Berghmans, F.; Thienpont, H.

    2005-09-01

    The field of optical fiber sensing is highly diverse and this diversity is perceived as a great advantage over more conventional sensors in that an optical sensor can be tailored to measure any of a myriad of physical parameters. In this paper we present a niche application for optical fiber sensors in the domain of biophotonics, namely the monitoring of stress build-up during the curing process of dental resin cements. We discuss the origin of this stress build-up and the problems it can cause when treating patients. Optical fiber sensors aim at excelling in two kind of applications: firstly to perform quality control on batch produced dental cements and measure their total material shrinkage, secondly to monitor the hardening of the cement during in-vivo measurements resulting in the dynamic measurement of the shrinkage and to control the stress in a facing based restoration. We therefore investigated two types of optical fiber sensors as alternatives to conventional measurement techniques; namely polarimetric optical fiber sensors and fiber Bragg gratings written in polarization maintaining fibers. After discussing the results obtained with both optical fiber sensors, we will conclude with a critical assessment of the suitability of the two proposed sensing configurations for multi-parameter stress monitoring.

  10. Impact of Eccentricity Build-Up and Graveyard Disposal Strategies on Meo Navigation Constellations

    NASA Astrophysics Data System (ADS)

    Radtke, Jonas; Flegel, Sven Kevin; Sanchez-Ortiz, Noelia; Dominguez-Gonzalez, Raul; Merz, Klaus

    With currently two constellations being in or close to the build-up phase, in a few years the Medium Earth Orbit (MEO) region will be populated with four complete navigation systems in relatively close orbital altitudes: The American GPS, Russian GLONASS, European Galileo and Chinese Beidou. To guarantee an appropriate visibility of constellation satellites from Earth, these constellations rely on certain defined orbits. For these, both the repeat pattern, which is basically defined by the semi-major axis and inclination, as well as the orbital planes, which are defined by the right ascension of ascending node, are important. To avoid an overcrowding of the region of interest, the disposal of satellites after their end-of-life is recommended. Because of their distances to Earth, ordinary disposal manoeuvers leading to a direct or delayed re-entry due to atmospheric drag are not feasible: The needed fuel masses for such manoeuvers are by far above the reasonable limits and available fuel budgets. Thus, additional approaches have to be applied. For this, in general two options do exist: Disposal to graveyard orbits or the disposal to eccentricity build-up orbits. For the graveyard strategy, the key criterium for the disposed spacecraft is that they must keep a safe minimum distance to altitude of the active constellation on a long-term time scale of up to 200 years. This constraint imposes stringent requirements on the stability of the graveyard orbit. Similar disposals are also performed for high LEO satellites. The eccentricity build-up strategy on the other hand uses an effect that is characteristic for the orbital regime of MEO navigation constellations: Due to resonant effects between the Earth's geopotential, the Sun and the Moon, depending on the initial conditions, a large eccentricity build-up takes place, which can lead to a re-entry of the satellite. In this paper, the effects of applying either the first or the second disposal strategy on all payloads

  11. Impact of eccentricity build-up and graveyard disposal Strategies on MEO navigation constellations

    NASA Astrophysics Data System (ADS)

    Radtke, Jonas; Domínguez-González, Raúl; Flegel, Sven K.; Sánchez-Ortiz, Noelia; Merz, Klaus

    2015-12-01

    With currently two constellations being in or close to the build-up phase, in a few years the Medium Earth Orbit (MEO) region will be populated with four complete navigation systems in relatively close orbital altitudes: The American GPS, Russian GLONASS, European Galileo, and Chinese BeiDou. To guarantee an appropriate visibility of constellation satellites from Earth, these constellations rely on certain defined orbits. For this, both the repeat pattern, which is basically defined by the semimajor axis and inclination, as well as the orbital planes, which are defined by the right ascension of ascending node, are determining values. To avoid an overcrowding of the region of interest, the disposal of satellites after their end-of-life is recommended. However, for the MEO region, no internationally agreed mitigation guidelines exist. Because of their distances to Earth, ordinary disposal manoeuvres leading to a direct or delayed re-entry due to atmospheric drag are not feasible: The needed fuel masses for such manoeuvres are by far above the reasonable limits and available fuel budgets. Thus, additional approaches have to be applied. For this, in general two options exist: disposal to graveyard orbits or the disposal to eccentricity build-up orbits. In the study performed, the key criterion for the graveyard strategy is that the disposed spacecraft must keep a safe minimum distance to the altitude of the active constellation on a long-term time scale of up to 200 years. This constraint imposes stringent requirements on the stability of the graveyard orbit. Similar disposals are also performed for high LEO satellites and disposed GEO payloads. The eccentricity build-up strategy on the other hand uses resonant effects between the Earth's geopotential, the Sun and the Moon. Depending on the initial conditions, these can cause a large eccentricity build-up, which finally can lead to a re-entry of the satellite. In this paper, the effects of applying either the first or

  12. [11C]phenytoin revisited: synthesis by [11C]CO carbonylation and first evaluation as a P-gp tracer in rats

    PubMed Central

    2012-01-01

    Background At present, several positron emission tomography (PET) tracers are in use for imaging P-glycoprotein (P-gp) function in man. At baseline, substrate tracers such as R-[11C]verapamil display low brain concentrations with a distribution volume of around 1. [11C]phenytoin is supposed to be a weaker P-gp substrate, which may lead to higher brain concentrations at baseline. This could facilitate assessment of P-gp function when P-gp is upregulated. The purpose of this study was to synthesize [11C]phenytoin and to characterize its properties as a P-gp tracer. Methods [11C]CO was used to synthesize [11C]phenytoin by rhodium-mediated carbonylation. Metabolism and, using PET, brain pharmacokinetics of [11C]phenytoin were studied in rats. Effects of P-gp function on [11C]phenytoin uptake were assessed using predosing with tariquidar. Results [11C]phenytoin was synthesized via [11C]CO in an overall decay-corrected yield of 22 ± 4%. At 45 min after administration, 19% and 83% of radioactivity represented intact [11C]phenytoin in the plasma and brain, respectively. Compared with baseline, tariquidar predosing resulted in a 45% increase in the cerebral distribution volume of [11C]phenytoin. Conclusions Using [11C]CO, the radiosynthesis of [11C]phenytoin could be improved. [11C]phenytoin appeared to be a rather weak P-gp substrate. PMID:22747744

  13. The use of tetrabutylammonium fluoride to promote N- and O-(11) C-methylation reactions with iodo[(11) C]methane in dimethyl sulfoxide.

    PubMed

    Kikuchi, Tatsuya; Minegishi, Katsuyuki; Hashimoto, Hiroki; Zhang, Ming-Rong; Kato, Koichi

    2013-11-01

    The N- or O-methylation reactions of compounds bearing amide, aniline, or phenol moieties using iodo[(11) C]methane (1) with the aid of a base are frequently applied to the preparation of (11) C-labeled radiopharmaceuticals. Although sodium hydride and alkaline metal hydroxides are commonly employed as bases in these reactions, their poor solubility properties in organic solvents and hydrolytic activities have sometimes limited their application and made the associated (11) C-methylation reactions difficult. In contrast to these bases, tetrabutylammonium fluoride (TBAF) is moderately basic, highly soluble in organic solvents, and weakly nucleophilic. Although it was envisaged that TBAF could be used as the preferred base for (11) C-methylation reactions using 1, studies concerning the use of TBAF to promote (11) C-methylation reactions are scarce. Herein, we have evaluated the efficiency of the (11) C-methylation reactions of 13 model compounds using TBAF and 1. In most cases, the N-(11) C-methylations were efficiently promoted by TBAF in dimethyl sulfoxide at ambient temperature, whereas the O-(11) C-methylations required heating in some cases. Comparison studies revealed that the efficiencies of the (11) C-methylation reactions with TBAF were comparable or sometimes greater than those conducted with sodium hydride. Based on these results, TBAF should be considered as the preferred base for (11) C-methylation reactions using 1. PMID:25196029

  14. Analytical expressions for the gate utilization factors of passive multiplicity counters including signal build-up

    SciTech Connect

    Croft, Stephen; Evans, Louise G; Schear, Melissa A

    2010-01-01

    In the realm of nuclear safeguards, passive neutron multiplicity counting using shift register pulse train analysis to nondestructively quantify Pu in product materials is a familiar and widely applied technique. The approach most commonly taken is to construct a neutron detector consisting of {sup 3}He filled cylindrical proportional counters embedded in a high density polyethylene moderator. Fast neutrons from the item enter the moderator and are quickly slowed down, on timescales of the order of 1-2 {micro}s, creating a thermal population which then persists typically for several 10's {micro}s and is sampled by the {sup 3}He detectors. Because the initial transient is of comparatively short duration it has been traditional to treat it as instantaneous and furthermore to approximate the subsequent capture time distribution as exponential in shape. With these approximations simple expressions for the various Gate Utilization Factors (GUFs) can be obtained. These factors represent the proportion of time correlated events i.e. Doubles and Triples signal present in the pulse train that is detected by the coincidence gate structure chosen (predelay and gate width settings of the multiplicity shift register). More complicated expressions can be derived by generalizing the capture time distribution to multiple time components or harmonics typically present in real systems. When it comes to applying passive neutron multiplicity methods to extremely intense (i.e. high emission rate and highly multiplying) neutron sources there is a drive to use detector types with very fast response characteristics in order to cope with the high rates. In addition to short pulse width, detectors with a short capture time profile are also desirable so that a short coincidence gate width can be set in order to reduce the chance or Accidental coincidence signal. In extreme cases, such as might be realized using boron loaded scintillators, the dieaway time may be so short that the build-up

  15. Development of a modular system for the synthesis of PET [(11)C]labelled radiopharmaceuticals.

    PubMed

    Boschi, Stefano; Lodi, Filippo; Cicoria, Gianfranco; Raul Ledesma, Jorge; Knopp, Roger; Rizzello, Anna; Di Pierro, Donato; Trespidi, Silvia; Marengo, Mario

    2009-10-01

    [((11))C]labelled radiopharmaceuticals as N-[(11)C]methyl-choline ([(11)C]choline), l-(S-methyl-[(11)C])methionine ([(11)C]methionine) and [(11)C]acetate have gained increasing importance in clinical PET and for the routine production of these radiopharmaceuticals, simple and reliable modules are needed to produce clinically relevant radioactivity. On the other hand, flexible devices are needed not only for the routine synthesis but also for more complex applications as the development of new tracers. The aim of this work was the adaptation of an Eckert Ziegler modular system for easy routine synthesis of [(11)C]choline, [(11)C]methionine and [(11)C]acetate using components that account for straightforward scaling up and upgrades. PMID:19535255

  16. Acoustic build-up in on-chip stimulated Brillouin scattering

    NASA Astrophysics Data System (ADS)

    Wolff, C.; Steel, M. J.; Eggleton, B. J.; Poulton, C. G.

    2015-09-01

    We investigate the role of the spatial evolution of the acoustic field in stimulated Brillouin scattering processes in short high-gain structures. When the gain is strong enough that the gain length becomes comparable to the acoustic wave decay length of order 100 microns, standard approximations treating the acoustic field as a local response no longer apply. Treating the acoustic evolution more accurately, we find that the backward SBS gain of sub-millimetre long waveguides is significantly reduced from the value obtained by the conventional treatment because the acoustic mode requires several decay lengths to build up to its nominal value. In addition, the corresponding resonance line is broadened with the development of side bands. In contrast, we argue that intra-mode forward SBS is not expected to show these effects. Our results have implications for several recent proposals and experiments on high-gain stimulated Brillouin scattering in short semiconductor waveguides.

  17. Model Study of the Pressure Build-Up during Subcutaneous Injection

    PubMed Central

    Thomsen, Maria; Hernandez-Garcia, Anier; Mathiesen, Joachim; Poulsen, Mette; Sørensen, Dan N.; Tarnow, Lise; Feidenhans'l, Robert

    2014-01-01

    In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws of a porous medium. For equivalent injection forces we measure the change in the infusion rate between injections in air at atmospheric pressure and in tissue. From a best fit with our model, we then determine the flow permeability as well as the bulk modulus of the tissue, estimated to be of the order 10−11–10−10 m2 and 105 Pa, respectively. The permeability is in good agreement with reported values for adipose porcine tissue. We suggest our model as a general way to estimate the pressure build-up in tissue during subcutaneous injection. PMID:25122138

  18. Acoustic build-up in on-chip stimulated Brillouin scattering

    PubMed Central

    Wolff, C.; Steel, M. J.; Eggleton, B. J.; Poulton, C. G.

    2015-01-01

    We investigate the role of the spatial evolution of the acoustic field in stimulated Brillouin scattering processes in short high-gain structures. When the gain is strong enough that the gain length becomes comparable to the acoustic wave decay length of order 100 microns, standard approximations treating the acoustic field as a local response no longer apply. Treating the acoustic evolution more accurately, we find that the backward SBS gain of sub-millimetre long waveguides is significantly reduced from the value obtained by the conventional treatment because the acoustic mode requires several decay lengths to build up to its nominal value. In addition, the corresponding resonance line is broadened with the development of side bands. In contrast, we argue that intra-mode forward SBS is not expected to show these effects. Our results have implications for several recent proposals and experiments on high-gain stimulated Brillouin scattering in short semiconductor waveguides. PMID:26338720

  19. Pharmacokinetic Analysis of 11C-PBR28 in the Rat Model of Herpes Encephalitis: Comparison with (R)-11C-PK11195.

    PubMed

    Parente, Andrea; Feltes, Paula Kopschina; Vállez García, David; Sijbesma, Jurgen W A; Moriguchi Jeckel, Cristina M; Dierckx, Rudi A J O; de Vries, Erik F J; Doorduin, Janine

    2016-05-01

    (11)C-PBR28 is a second-generation translocator protein (TSPO) tracer with characteristics supposedly superior to the most commonly used tracer for neuroinflammation, (R)-(11)C-PK11195. Despite its use in clinical research, no studies on the imaging properties and pharmacokinetic analysis of (11)C-PBR28 in rodent models of neuroinflammation have been published yet. Therefore, this study aimed to evaluate (11)C-PBR28 as a tool for detection and quantification of neuroinflammation in preclinical research and to compare its imaging properties with (R)-(11)C-PK11195. The herpes simplex encephalitis (HSE) model was used for induction of neuroinflammation in male Wistar rats. Six or 7 d after virus inoculation, a dynamic (11)C-PBR28 or (R)-(11)C-PK11195 PET scan with arterial blood sampling was obtained. Pharmacokinetic modeling was performed on the PET data and analyzed using volumes of interest and a voxel-based approach. Volume-of-interest- and voxel-based analysis of (11)C-PBR28 images showed overexpression of TSPO in brain regions known to be affected in the HSE rat model. (11)C-PBR28 was metabolized faster than (R)-(11)C-PK11195, with a metabolic half-life in plasma of 5 and 21 min, respectively. Overall, (11)C-PBR28 was more sensitive than (R)-(11)C-PK11195 in detecting neuroinflammation. The binding potential (BPND) of (11)C-PBR28 was significantly higher (P < 0.05) in the medulla (176%), pons (146%), midbrain (101%), hippocampus (85%), thalamus (73%), cerebellum (54%), and hypothalamus (49%) in HSE rats than in control rats, whereas (R)-(11)C-PK11195 showed a higher BPND only in the medulla (32%). The BPND in control animals was not significantly different between tracers, suggesting that the nonspecific binding of both tracers is similar. (11)C-PBR28 was more sensitive than (R)-(11)C-PK11195 in the detection of TSPO overexpression in the HSE rat model, because more brain regions with significantly increased tracer uptake could be found, irrespective of the data

  20. Can captive orangutans (Pongo pygmaeus abelii) be coaxed into cumulative build-up of techniques?

    PubMed

    Lehner, Stephan R; Burkart, Judith M; Schaik, Carel P van

    2011-11-01

    While striking cultural variation in behavior from one site to another has been described in chimpanzees and orangutans, cumulative culture might be unique to humans. Captive chimpanzees were recently found to be rather conservative, sticking to the technique they had mastered, even after more effective alternatives were demonstrated. Behavioral flexibility in problem solving, in the sense of acquiring new solutions after having learned another one earlier, is a vital prerequisite for cumulative build-up of techniques. Here, we experimentally investigate whether captive orangutans show such flexibility, and if so, whether they show techniques that cumulatively build up (ratchet) on previous ones after conditions of the task are changed. We provided nine Sumatran orangutans (Pongo pygmaeus abelii) with two types of transparent tubes partly filled with syrup, along with potential tools such as sticks, twigs, wood wool and paper. In the first phase, the orangutans could reach inside the tubes with their hands (Regular Condition), but in the following phase, tubes had been made too narrow for their hands to fit in (Restricted Condition 1), or in addition the setup lacked their favorite materials (Restricted Condition 2). The orangutans showed high behavioral flexibility, applying nine different techniques under the regular condition in total. Individuals abandoned preferred techniques and switched to different techniques under restricted conditions when this was advantageous. We show for two of these techniques how they cumulatively built up on earlier ones. This suggests that the near-absence of cumulative culture in wild orangutans is not due to a lack of flexibility when existing solutions to tasks are made impossible. PMID:21767010

  1. Comparison of photobleaching and fluence rate effects in PpIX and BPD-MA photosensitization of rat bladder tumor in vivo

    NASA Astrophysics Data System (ADS)

    Iinuma, Seiichi; Wagnieres, Georges A.; Schomacker, Kevin T.; Bamberg, Mike; Hasan, Tayyaba

    1995-05-01

    Photobleaching of 5-aminolevulinic acid (ALA) -induced protoporphyrin IX (PpIX) and benzoporphyrin derivative-monoacid ring A (BPD-MA) was investigated using an orthotopic rat bladder tumor model. For both photosensitizers used, the photobleaching rate constant was not fluence- rate-dependent under conditions that photodynamic response was fluence rate-dependent. These data suggest that photobleaching pathways may be independent of the photochemical paths involved in tissue destruction. The fluorescence spectrum was followed during irradiation by using laser-induced fluorescence method and a build-up of photoproducts of PpIX was observed whereas no fluorescence of photoproducts was obtained in the case of BPD-MA.

  2. Synthesis and 11C-Radiolabelling of 2-Carboranyl Benzothiazoles.

    PubMed

    Gona, Kiran B; Thota, Jaya Lakshmi V N P; Baz, Zuriñe; Gómez-Vallejo, Vanessa; Llop, Jordi

    2015-01-01

    Dicarba-closo-dodecaboranes, commonly known as carboranes, possess unique physico-chemical properties and can be used as hydrophobic moieties during the design of new drugs or radiotracers. In this work, we report the synthesis of two analogues of 2-(4-aminophenyl)benzothiazole (a compound that was found to elicit pronounced inhibitory effects against certain breast cancer cell lines in vitro) in which the phenyl ring has been substituted by a m-carborane cage. Two different synthetic strategies have been used. For the preparation of 1-(9-amino-1,7-dicarba-closo-dodecaboran-1-yl)-benzo-thiazole, the benzothiazole group was first introduced on one of the cluster carbon atoms of m-carborane and the amine group was further attached in three steps. For the synthesis of 1-(9-amino-1,7-dicarba-closo-dodecaboran-1-yl)-6-hydroxybenzothiazole, iodination was performed before introducing the benzothiazole group, and the amino group was subsequently introduced in six steps. Both compounds were radiolabelled with carbon-11 using [11C]CH3OTf as the labelling agent. Radiolabelling yields and radiochemical purities achieved should enable subsequent in vitro and in vivo investigations. PMID:25915463

  3. An automated classification approach to ranking photospheric proxies of magnetic energy build-up

    NASA Astrophysics Data System (ADS)

    Al-Ghraibah, A.; Boucheron, L. E.; McAteer, R. T. J.

    2015-07-01

    Aims: We study the photospheric magnetic field of ~2000 active regions over solar cycle 23 to search for parameters that may be indicative of energy build-up and its subsequent release as a solar flare in the corona. Methods: We extract three sets of parameters: (1) snapshots in space and time: total flux, magnetic gradients, and neutral lines; (2) evolution in time: flux evolution; and (3) structures at multiple size scales: wavelet analysis. This work combines standard pattern recognition and classification techniques via a relevance vector machine to determine (i.e., classify) whether a region is expected to flare (≥C1.0 according to GOES). We consider classification performance using all 38 extracted features and several feature subsets. Classification performance is quantified using both the true positive rate (the proportion of flares correctly predicted) and the true negative rate (the proportion of non-flares correctly classified). Additionally, we compute the true skill score which provides an equal weighting to true positive rate and true negative rate and the Heidke skill score to allow comparison to other flare forecasting work. Results: We obtain a true skill score of ~0.5 for any predictive time window in the range 2 to 24 h, with a true positive rate of ~0.8 and a true negative rate of ~0.7. These values do not appear to depend on the predictive time window, although the Heidke skill score (<0.5) does. Features relating to snapshots of the distribution of magnetic gradients show the best predictive ability over all predictive time windows. Other gradient-related features and the instantaneous power at various wavelet scales also feature in the top five (of 38) ranked features in predictive power. It has always been clear that while the photospheric magnetic field governs the coronal non-potentiality (and hence likelihood of producing a solar flare), photospheric magnetic field information alone is not sufficient to determine this in a unique manner

  4. Build-up Approach to Updating the Mock Quiet Spike(TM)Beam Model

    NASA Technical Reports Server (NTRS)

    Herrera, Claudia Y.; Pak, Chan-gi

    2007-01-01

    A crucial part of aircraft design is ensuring that the required margin for flutter is satisfied. A trustworthy flutter analysis, which begins by possessing an accurate dynamics model, is necessary for this task. Traditionally, a model was updated manually by fine tuning specific stiffness parameters until the analytical results matched test data. This is a time consuming iterative process. The NASA Dryden Flight Research Center has developed a mode matching code to execute this process in a more efficient manner. Recently, this code was implemented in the F-15B/Quiet Spike (Gulfstream Aerospace Corporation, Savannah, Georgia) model update. A build-up approach requiring several ground vibration test configurations and a series of model updates was implemented to determine the connection stiffness between aircraft and test article. The mode matching code successfully updated various models for the F-15B/Quiet Spike project to within 1 percent error in frequency and the modal assurance criteria values ranged from 88.51-99.42 percent.

  5. Build-up Approach to Updating the Mock Quiet Spike(TradeMark) Beam Model

    NASA Technical Reports Server (NTRS)

    Herrera, Claudia Y.; Pak, Chan-gi

    2007-01-01

    A crucial part of aircraft design is ensuring that the required margin for flutter is satisfied. A trustworthy flutter analysis, which begins by possessing an accurate dynamics model, is necessary for this task. Traditionally, a model was updated manually by fine tuning specific stiffness parameters until the analytical results matched test data. This is a time consuming iterative process. NASA Dryden Flight Research Center has developed a mode matching code to execute this process in a more efficient manner. Recently, this code was implemented in the F-15B/Quiet Spike(TradeMark) (Gulfstream Aerospace Corporation, Savannah, Georgia) model update. A build-up approach requiring several ground vibration test configurations and a series of model updates was implemented in order to determine the connection stiffness between aircraft and test article. The mode matching code successfully updated various models for the F-15B/Quiet Spike(TradeMark) project to within 1 percent error in frequency and the modal assurance criteria values ranged from 88.51-99.42 percent.

  6. Comparative study of mechanical properties of direct core build-up materials

    PubMed Central

    Kumar, Girish; Shivrayan, Amit

    2015-01-01

    Background and Objectives: The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. Materials and Methods: All the materials were manipulated according to the manufacturer's recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Results: Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Conclusions: Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success. PMID:25684905

  7. Serial PET studies of human cerebral malignancy with (1-/sup 11/C)putrescine and (1-/sup 11/C)2-deoxy-D-glucose

    SciTech Connect

    Hiesiger, E.; Fowler, J.S.; Wolf, A.P.; Logan, J.; Brodie, J.D.; McPherson, D.; MacGregor, R.R.; Christman, D.R.; Volkow, N.D.; Flamm, E.

    1987-08-01

    Serial PET measurements of (1-/sup 11/C)putrescine ((/sup 11/C)PUT) uptake and glucose metabolic rate (GMR) using (1-/sup 11/C)2-deoxy-D-glucose ((/sup 11/C)2DG) were made on eight human subjects with a radiological and, in most cases, pathological diagnosis of primary or metastatic brain tumor. Blood-to-brain influx constants (Ki) were calculated for (/sup 11/C)PUT. Tumor uptake of /sup 11/C after (/sup 11/C)PUT injection was unidirectional peaking at 15 min. The mean +/- s.d. Kis for (/sup 11/C)PUT for tumor and normal brain tissue were 0.78 +/- 0.045 and 0.024 +/- 0.007 ml cc-1 min-1, respectively (average of ratio, 3.11 whereas the ratio of GMR for tumor and normal brain tissue was 1.2 +/- 0.5. The mean Ki for four active, high grade astrocytomas was 0.098 +/- 0.030 in contrast to 0.027 +/- 0.008 ml cc-1 min-1 for two patients with low grade astrocytoma. Active high grade astrocytomas also showed marked CT contrast enhancement and regional glucose hypermetabolism. In one subject with brain metastases, both (/sup 11/C)PUT and GMR correlated with a declining clinical picture in repeated studies over a 4-mo period. PET studies with (/sup 11/C)PUT provide a better signal:noise ratio than GMR measurements, are useful for locating small glycolytically hypometabolic tumors and, when used in longitudinal studies in a single subject, appear to provide an index of degree of malignancy.

  8. Target design considerations for high specific activity [{sup 11}C]O{sub 2}

    SciTech Connect

    Ferrieri, R.A.; Alexoff, D.L.; Schlyer, D.J.; McDonald, K.; Wolf, A.P.

    1993-12-31

    In the routine preparation of {sup 11}C-labeled compounds through N-[{sup 11}C]-methylation using [{sup 11}C]H{sub 3}I, total masses are always higher than synthesis mass contribution, suggesting that the target system contributes carrier carbon to the final product mass. This conclusion prompted this evaluation of target materials and target design for [{sup 11}C]O{sub 2} production. Ultimately, one is faced with the sprospect of compromising between [{sup 11}C]O{sub 2} specific activity and the amount that can be extracted from the target after a reasonable irradiation time.

  9. Influence of uncertainty inherent to heavy metal build-up and wash-off on stormwater quality.

    PubMed

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2016-03-15

    Uncertainty inherent to heavy metal build-up and wash-off stems from process variability. This results in inaccurate interpretation of stormwater quality model predictions. The research study has characterised the variability in heavy metal build-up and wash-off processes based on the temporal variations in particle-bound heavy metals commonly found on urban roads. The study outcomes found that the distribution of Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb were consistent over particle size fractions <150 μm and >150 μm, with most metals concentrated in the particle size fraction <150 μm. When build-up and wash-off are considered as independent processes, the temporal variations in these processes in relation to the heavy metals load are consistent with variations in the particulate load. However, the temporal variations in the load in build-up and wash-off of heavy metals and particulates are not consistent for consecutive build-up and wash-off events that occur on a continuous timeline. These inconsistencies are attributed to interactions between heavy metals and particulates <150 μm and >150 μm, which are influenced by particle characteristics such as organic matter content. The behavioural variability of particles determines the variations in the heavy metals load entrained in stormwater runoff. Accordingly, the variability in build-up and wash-off of particle-bound pollutants needs to be characterised in the description of pollutant attachment to particulates in stormwater quality modelling. This will ensure the accounting of process uncertainty, and thereby enhancing the interpretation of the outcomes derived from modelling studies. PMID:26803262

  10. Optimization of [11C]DASB-synthesis: vessel-based and flow-through microreactor methods.

    PubMed

    Ungersboeck, Johanna; Philippe, Cecile; Haeusler, Daniela; Mitterhauser, Markus; Lanzenberger, Rupert; Dudczak, Robert; Wadsak, Wolfgang

    2012-11-01

    The intention for the present study was to implement a microfluidic set-up for N-(11)C-methylations in a flow-through microreactor device with [(11)C]DASB as model-compound and [(11)C]CH(3)I and [(11)C]CH(3)OTf, respectively, as (11)C-methylation agents. Due to an observed "aging" effect of the (11)C-methylation agents' solution, this goal was not achieved. Nevertheless, based on these observations, the time consumption for the vessel-based routine production of [(11)C]DASB was reduced (34±1 min) and RCY was increased to 45.1±4.6% (EOB; 5.2±0.95 GBq EOS). PMID:22940416

  11. An efficient and practical synthesis of [2-11C]indole via superfast nucleophilic [11C]cyanation and RANEY® Nickel catalyzed reductive cyclization

    DOE PAGESBeta

    So Jeong Lee; Fowler, Joanna S.; Alexoff, David; Schueller, Michael; Kim, Dohyun; Nauth, Alexander; Weber, Carina; Kim, Sung Won; Hooker, Jacob M.; Ma, Ling; et al

    2015-09-21

    We developed a rapid method for the synthesis of carbon-11 radiolabeled indole using a sub-nanomolar quantity of no-carrier-added [11C]cyanide as radio-precursor. Based upon a reported synthesis of 2-(2-nitrophenyl)acetonitrile (2), a highly reactive substrate 2-nitrobenzyl bromide (1) was evaluated for nucleophilic [11C]cyanation. Additionally, related reaction conditions were explored with the goal of obtaining of highly reactive 2-(2-nitrophenyl)-[1-11C]acetonitrile ([11C]-2) while inhibiting its rapid conversion to 2,3-bis(2-nitrophenyl)-[1-11C]propanenitrile ([11C]-3). Next, a Raney Nickel catalyzed reductive cyclization method was utilized for synthesizing the desired [2-11C]indole with hydrazinium monoformate as the active reducing agent. Extensive and iterative screening of basicity, temperature and stoichiometry was required tomore » overcome the large stoichiometry bias that favored 2-nitrobenzylbromide (1) over [11C]cyanide, which both caused further alkylation of the desired nitrile and poisoned the Raney Nickel catalyst. The result is an efficient two-step, streamlined method to reliably synthesize [2-11C]indole with an entire radiochemical yield of 21 ± 2.2% (n = 5, ranging from 18 – 24%). The radiochemical purity of the final product was > 98% and specific activity was 176 ± 24.8 GBq/μmol (n = 5, ranging from 141 – 204 GBq/μmol). The total radiosynthesis time including product purification by semi-preparative HPLC was 50 – 55 min from end of cyclotron bombardment.« less

  12. Algorithms for optimizing CT fluence control

    NASA Astrophysics Data System (ADS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-03-01

    The ability to customize the incident x-ray fluence in CT via beam-shaping filters or mA modulation is known to improve image quality and/or reduce radiation dose. Previous work has shown that complete control of x-ray fluence (ray-by-ray fluence modulation) would further improve dose efficiency. While complete control of fluence is not currently possible, emerging concepts such as dynamic attenuators and inverse-geometry CT allow nearly complete control to be realized. Optimally using ray-by-ray fluence modulation requires solving a very high-dimensional optimization problem. Most optimization techniques fail or only provide approximate solutions. We present efficient algorithms for minimizing mean or peak variance given a fixed dose limit. The reductions in variance can easily be translated to reduction in dose, if the original variance met image quality requirements. For mean variance, a closed form solution is derived. The peak variance problem is recast as iterated, weighted mean variance minimization, and at each iteration it is possible to bound the distance to the optimal solution. We apply our algorithms in simulations of scans of the thorax and abdomen. Peak variance reductions of 45% and 65% are demonstrated in the abdomen and thorax, respectively, compared to a bowtie filter alone. Mean variance shows smaller gains (about 15%).

  13. A comprehensive interpretation of the NEEM basal ice build-up using a multi parametric approach

    NASA Astrophysics Data System (ADS)

    Goossens, Thomas; Sapart, Celia Julia; Popp, Trevor; El Amri, Saïda; Tison, Jean-louis

    2015-04-01

    Basal ice is a common expression to describe debris-laden ice layers found close to the ice-bedrock interface under glaciers and ice sheets. The study of basal ice properties provides us with the unique opportunity of improving our understanding of subglacial environments and processes and refine ice sheet behaviour modelling. Here, we present and discuss the results of water stable isotopes (δ18O and δD), ice fabrics, debris weight and gas content of the basal part of the NEEM (North Eemian Ice Drilling Program) ice core. Below 2533.85 m deep, almost 10 m of basal debris-rich material were retrieved from the borehole. The situation at NEEM is different from the previously well-documented GRIP core where the basal ice corresponds to pre ice sheet ice overridden by the growing ice sheet. At NEEM, the basal debris-rich material presents δ18O values from -39.89 to -34.36 permil within the range of the above last 300 m of meteoric ice from -44.86 to -30.59 permil. The sequence is however composed of an alternation of three visually contrasting types of ice : clear ice with specks of particulate inclusions, stratified debris-rich layers, and ice containing dispersed debris. Using water stable isotopes (δ18O and δ D) signatures, each of these ice types are discriminated and clues are given for their conditions of formation and transformation processes. The proposed interpretation is then refined in the light of the other available parameters. While clear basal ice with specks corresponds to altered meteoric glacial ice, stratified debris-rich layer and ice containing dispersed debris present a melting/refreezing signature, somewhat blurred by mixing processes. Based on the identified origins of the different ice types, the present study proposes a first interpretative framework for the build-up of the NEEM basal ice sequence.

  14. How does the interaction between spelling and motor processes build up during writing acquisition?

    PubMed

    Kandel, Sonia; Perret, Cyril

    2015-03-01

    How do we recall a word's spelling? How do we produce the movements to form the letters of a word? Writing involves several processing levels. Surprisingly, researchers have focused either on spelling or motor production. However, these processes interact and cannot be studied separately. Spelling processes cascade into movement production. For example, in French, producing letters PAR in the orthographically irregular word PARFUM (perfume) delays motor production with respect to the same letters in the regular word PARDON (pardon). Orthographic regularity refers to the possibility of spelling a word correctly by applying the most frequent sound-letter conversion rules. The present study examined how the interaction between spelling and motor processing builds up during writing acquisition. French 8-10 year old children participated in the experiment. This is the age handwriting skills start to become automatic. The children wrote regular and irregular words that could be frequent or infrequent. They wrote on a digitizer so we could collect data on latency, movement duration and fluency. The results revealed that the interaction between spelling and motor processing was present already at age 8. It became more adult-like at ages 9 and 10. Before starting to write, processing irregular words took longer than regular words. This processing load spread into movement production. It increased writing duration and rendered the movements more dysfluent. Word frequency affected latencies and cascaded into production. It modulated writing duration but not movement fluency. Writing infrequent words took longer than frequent words. The data suggests that orthographic regularity has a stronger impact on writing than word frequency. They do not cascade in the same extent. PMID:25525970

  15. The accelerated build-up of the red sequence in high-redshift galaxy clusters

    NASA Astrophysics Data System (ADS)

    Cerulo, P.; Couch, W. J.; Lidman, C.; Demarco, R.; Huertas-Company, M.; Mei, S.; Sánchez-Janssen, R.; Barrientos, L. F.; Muñoz, R. P.

    2016-04-01

    We analyse the evolution of the red sequence in a sample of galaxy clusters at redshifts 0.8 < z < 1.5 taken from the HAWK-I Cluster Survey (HCS). The comparison with the low-redshift (0.04 < z < 0.08) sample of the WIde-field Nearby Galaxy-cluster Survey (WINGS) and other literature results shows that the slope and intrinsic scatter of the cluster red sequence have undergone little evolution since z = 1.5. We find that the luminous-to-faint ratio and the slope of the faint end of the luminosity distribution of the HCS red sequence are consistent with those measured in WINGS, implying that there is no deficit of red galaxies at magnitudes fainter than M_V^{ast } at high redshifts. We find that the most massive HCS clusters host a population of bright red sequence galaxies at MV < -22.0 mag, which are not observed in low-mass clusters. Interestingly, we also note the presence of a population of very bright (MV < -23.0 mag) and massive (log (M*/M⊙) > 11.5) red sequence galaxies in the WINGS clusters, which do not include only the brightest cluster galaxies and which are not present in the HCS clusters, suggesting that they formed at epochs later than z = 0.8. The comparison with the luminosity distribution of a sample of passive red sequence galaxies drawn from the COSMOS/UltraVISTA field in the photometric redshift range 0.8 < zphot < 1.5 shows that the red sequence in clusters is more developed at the faint end, suggesting that halo mass plays an important role in setting the time-scales for the build-up of the red sequence.

  16. Young and embedded clusters in Cygnus-X: evidence for building up the initial mass function?

    NASA Astrophysics Data System (ADS)

    Maia, F. F. S.; Moraux, E.; Joncour, I.

    2016-05-01

    We provide a new view on the Cygnus-X north complex by accessing for the first time the low mass content of young stellar populations in the region. Canada-France-Hawaii Telescope/Wide-Field Infrared Camera was used to perform a deep near-infrared survey of this complex, sampling stellar masses down to ˜0.1 M⊙. Several analysis tools, including a extinction treatment developed in this work, were employed to identify and uniformly characterize a dozen unstudied young star clusters in the area. Investigation of their mass distributions in low-mass domain revealed a relatively uniform log-normal initial mass function (IMF) with a characteristic mass of 0.32 ± 0.08 M⊙ and mass dispersion of 0.40 ± 0.06. In the high-mass regime, their derived slopes showed that while the youngest clusters (age < 4 Myr) presented slightly shallower values with respect to the Salpeter's, our older clusters (4 Myr < age < 18 Myr) showed IMF compliant values and a slightly denser stellar population. Although possibly evidencing a deviation from an `universal' IMF, these results also supports a scenario where these gas-dominated young clusters gradually `build up' their IMF by accreting low-mass stars formed in their vicinity during their first ˜3 Myr, before the gas expulsion phase, emerging at the age of ˜4 Myr with a fully fledged IMF. Finally, the derived distances to these clusters confirmed the existence of at least three different star-forming regions throughout Cygnus-X north complex, at distances of 500-900 pc, 1.4-1.7 and 3.0 kpc, and revealed evidence of a possible interaction between some of these stellar populations and the Cygnus OB2 association.

  17. Gradual Inflation of Coronal Arcades Building up to Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Liu, Rui; Liu, C.; Park, S.; Wang, H.

    2010-05-01

    The pre-CME structure is of great importance to understanding the origin of CMEs, which, however, has been largely unknown for CMEs originating from active regions. In this presentation, we investigate this issue using the wavelet-enhanced EUV Imaging Telescope observations combined with the Large Angle and Spectrometric Coronagraph, Michelson Doppler Imager, and GOES soft X-ray observations. Two types of active-region coronal arcades whose gradual inflation may build up to CMEs are identified, namely, post-eruptive arcades and overlying arcades. The observed inflation of 16 selected events sustains for 8.7 +/- 4.1 hours, with the arcade rising from 1.15 +/- 0.06 to 1.36 +/- 0.07 solar radii at a speed of less than 5 km/s, which eventually blast up as a CME similar in morphology to the pre-CME arcade. For the 4 events that were observed on the disk, it is found that the gradual inflation of the arcade is temporally associated with the helicity injection from photosphere. This pre-CME structure is apparently unaffected by the flares occurring during its quasi-static inflation phase, but is closely coupled with the flare occurring during its acceleration phase. In particular, a swirling structure, which is reminiscent of a magnetic flux rope, was observed in one of the arcades over 4 hrs prior to the subsequent CME, and the growth of the arcade is temporally associated with the injection of helicity of opposite sense into the active region via flux emergence. We propose a four-phase evolution paradigm for the observed CMEs, i.e., a quasi-static inflation phase which corresponds to the buildup of magnetic free energy in the corona, followed by the frequently observed three-phase paradigm, including an initial phase, an acceleration phase and a gradual phase.

  18. Binding of nitrided type 410 stainless steel valve stems caused by corrosion product build-up

    SciTech Connect

    Coffin, S.M.; Hardies, R.O.

    1996-10-01

    Nitrided type 410 stainless steel governor valve stems are used in safety-related reactor core isolation cooling (RCIC) and auxiliary feedwater (AFW) pumps at Boiling Water Reactors and Pressurized Water Reactors, respectively. Corrosion of the governor valve stems in the packing assembly area has been noted in at least seventeen nuclear power plants. Corrosion product build-up between the valve stem and packing assembly has resulted in binding of the valve stem in at least nine of these plants. Nitriding is known to degrade the corrosion resistance of, stainless steels. This is due to the formation of chromium nitrides in the diffusion layer of the hardened case which leave the surrounding matrix depleted in chromium. The rate of corrosion is substantially affected by the presence or absence of a continuous, adherent compound layer. The compound layer is less susceptible to corrosion than the diffusion layer and acts to protect the underlying diffusion layer from being exposed to moisture. At Calvert Cliffs, the original nitrided stem had a continuous, adherent compound layer and a hardened case of approximately 60 microns in depth. This stem performed acceptably for years. In contrast, the replacement nitrided stems did not have a continuous, adherent compound layer and had a hardened case of approximately 10 microns in depth. These stems performed acceptably for three or four months. This difference in performance is attributed primarily to the absence of an adherent, continuous compound layer in the recently-supplied nitrided stems. Since nitrided type 410 stainless steel valve stems will corrode in the presence of moisture (although at substantially different rates), the replacement valve stems will be fabricated from Inconel 718.

  19. Comparison of (+)-11C-McN5652 and 11C-DASB as Serotonin Transporter Radioligands Under Various Experimental Conditions

    PubMed Central

    Szabo, Zsolt; McCann, Una D.; Wilson, Alan A.; Scheffel, Ursula; Owonikoko, Taofeek; Mathews, William B.; Ravert, Hayden T.; Hilton, John; Dannals, Robert F.; Ricaurte, George A.

    2007-01-01

    There has been considerable interest in the development of a PET radioligand selective for the serotonin (5-hydroxytryptamine [5-HT]) transporter (SERT) that can be used to image 5-HT neurons in the living human brain. The most widely used SERT radiotracer to date, trans-1,2,3,5,6,10-β-hexahydro-6-[4-(methylthio)phenyl[pyrrolo-[2,1-a]isoquinoline ((+)-11C-McN5652), has been successful in this regard but may have some limitations. Recently, another promising SERT radiotracer, 3-11C-amino-4-(2-dimethylaminomethylphenylsulfanyl)benzonitrile (11C-DASB), has been described. The purpose of this study was to compare and contrast (+)-11C-McN5652 and 11C-DASB under various experimental conditions. Methods: Radioligand comparisons were performed in a control baboon, a baboon with reduced SERT density ((±)-3,4-methylenedioxymethamphetamine [MDMA] lesion), and a baboon with reduced SERT availability (paroxetine pretreatment). Under each of these experimental conditions, repeated (triplicate) PET studies were performed with each ligand. Results: Both radiotracers bound preferentially in brain regions known to contain high SERT density. For both ligands, there was a high correlation between the amount of regional brain ligand binding and the known regional brain concentration of SERT. Binding of both ligands was decreased after MDMA neurotoxicity (reduced SERT density), and (+)-11C-McN5652 and 11C-DASB were comparably effective in detecting reduced SERT density after MDMA-induced 5-HT neurotoxicity. Pretreatment with paroxetine dramatically altered the metabolism and kinetics of both tracers and appeared to displace both ligands primarily from regions with high SERT density. Compared with (+)-11C-McN5652, 11C-DASB had higher brain activity and a faster washout rate and provided greater contrast between subcortical and cortical brain regions. Conclusion: 11C-DASB and (+)-11C-McN5652 are suitable as PET ligands of the SERT and for detecting MDMA-induced 5-HT neurotoxicity. 11C

  20. The solar physics shuttle/Spacelab program and its relationship to studies of the flare build-up

    NASA Technical Reports Server (NTRS)

    Neupert, W. M.

    1975-01-01

    The definition of the NASA program to support astronomical observations from shuttle/Spacelab is discussed. Steps are described which were taken to insure that instruments to be used in specific scientific efforts such as a flare build-up study have flight opportunities.

  1. [11C]PR04.MZ, a promising DAT ligand for low concentration imaging: synthesis, efficient 11C-0-methylation and initial small animal PET studies

    SciTech Connect

    Riss, P.J.; Hooker, J.; Alexoff, D.; Kim, Sung-Won; Fowler, J.S.; Roesch, F.

    2009-05-01

    PR04.MZ was designed as a highly selective dopamine transporter inhibitor, derived from natural cocaine. Its binding profile indicates that [{sup 11}C]PR04.MZ may be suited as a PET radioligand for the non-invasive exploration of striatal and extrastriatal DAT populations. As a key feature, its structural design facilitates both, labelling with fluorine-18 at its terminally fluorinated butynyl moiety and carbon-11 at its methyl ester function. The present report concerns the efficient [{sup 11}C]MeI mediated synthesis of [{sup 11}C]PR04.MZ from an O-desmethyl precursor trifluoroacetic acid salt with Rb{sub 2}CO{sub 3} in DMF in up to 95 {+-} 5% labelling yield. A preliminary {mu}PET-experiment demonstrates the reversible, highly specific binding of [{sup 11}C]PR04.MZ in the brain of a male Sprague-Dawley rat.

  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. Improving compound–protein interaction prediction by building up highly credible negative samples

    PubMed Central

    Liu, Hui; Sun, Jianjiang; Guan, Jihong; Zheng, Jie; Zhou, Shuigeng

    2015-01-01

    Motivation: Computational prediction of compound–protein interactions (CPIs) is of great importance for drug design and development, as genome-scale experimental validation of CPIs is not only time-consuming but also prohibitively expensive. With the availability of an increasing number of validated interactions, the performance of computational prediction approaches is severely impended by the lack of reliable negative CPI samples. A systematic method of screening reliable negative sample becomes critical to improving the performance of in silico prediction methods. Results: This article aims at building up a set of highly credible negative samples of CPIs via an in silico screening method. As most existing computational models assume that similar compounds are likely to interact with similar target proteins and achieve remarkable performance, it is rational to identify potential negative samples based on the converse negative proposition that the proteins dissimilar to every known/predicted target of a compound are not much likely to be targeted by the compound and vice versa. We integrated various resources, including chemical structures, chemical expression profiles and side effects of compounds, amino acid sequences, protein–protein interaction network and functional annotations of proteins, into a systematic screening framework. We first tested the screened negative samples on six classical classifiers, and all these classifiers achieved remarkably higher performance on our negative samples than on randomly generated negative samples for both human and Caenorhabditis elegans. We then verified the negative samples on three existing prediction models, including bipartite local model, Gaussian kernel profile and Bayesian matrix factorization, and found that the performances of these models are also significantly improved on the screened negative samples. Moreover, we validated the screened negative samples on a drug bioactivity dataset. Finally, we derived

  4. Public health policy and the building up of a Brazilian medical identity.

    PubMed

    de Castro-Santos, L A

    2005-12-01

    Since George Herbert Mead studied "the social self" and the interactionists went further in distinguishing "images of self", a lecture on the building up of a Brazilian medical identity should try to focus on the patterns of self-images, presented images, and aspired-to images among the Brazilian medical elites during the First Republic (1889-1930). In no other period of Brazilian history were those "images" of professional identity so close--in contrast, later periods of Brazilian history witnessed an almost permanent "collision" or the clashing of such images among public health specialists. Oswaldo Cruz, Carlos Chagas, Artur Neiva and Belisário Pena are perhaps the best examples of successful careers as "sanitarians" (to recall John Duffy's historical work on luminaries before and after the "New Public Health" in the United States), and as important political actors during Brazil's First Republic. In light of the prominent political, policy-oriented, and scientific roles public health professionals played in Brazil, it is interesting to suggest that in large part such prominence resulted from the symbolic impact of the ideologies of sanitary reform on the political agenda of that period of Brazilian history. Where many studies look for personal rivalries and disputes around Chagas and Neiva as public figures, we may also see the importance of finding identity-building processes among public health specialists as an integrated group (e.g., trying to appear as "significant others" for the new generations of medical graduates in the country), regardless of existing rivalries. Cruz and Chagas, especially, were names with great impact in the Brazilian press (pro and con), a circumstance made possible largely by their easy and direct access to the Brazilian presidents Rodrigues Alves and Epitácio Pessoa, and, most clearly, by public health being one of Brazil's political priorities to find a place among the "civilized nations" of the world. A task that further

  5. Clinical comparison of various esthetic restorative options for coronal build-up of primary anterior teeth

    PubMed Central

    Duhan, Himanshu; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika; Kochhar, Gulsheen Kaur

    2015-01-01

    Background: This study was designed to compare the clinical performance of composite, strip crowns, biological restoration, and composite with stainless steel band when used for the coronal build-up of anterior teeth. Materials and Methods: A total of 20 patients aged 3-6 years presenting with mutilated primary anterior teeth due to caries or trauma were selected for the study using randomized simple sampling. A total of 52 primary anterior teeth were randomly divided into four equal groups having 13 teeth in each group. Teeth in Group I were restored with composite, in Group II with strip crowns, in Group III with biologic restoration and with stainless steel band reinforced composite in group IV. The restorations were evaluated for color match, retention, surface texture, and anatomic form according to Ryge's Direct (US Public Health Service) evaluation criteria at baseline (immediate postoperative), after 48 h, 3, 6, and 9 months. The data obtained were statistically analyzed using Chi-square test, and level of significance, that is, P value was determined. Results: At baseline, none of the groups showed any color changes. Other than Group III all other groups showed highly significant changes (P < 0.05) in color after 3 months. Loss of retention was seen in both Groups I and IV after 3 months. After 6 months, retention loss was seen in all the groups except Group II, in which loss was seen after 9 months (P > 0.05). Deterioration in surface texture was exhibited maximum by restorations in Group IV followed by Group I at 3 months. Whereas, no surface changes were seen in Group II and III. Only Group I and IV showed discontinuity in anatomic form after 3 months. After 6 months, except in Group II, discontinuity in anatomic form was observed in all the groups. Discontinuity in anatomic form was seen in all the 4 groups after 9 months although the difference was not significant (P > 0.05). Conclusion: Biological restoration was found to be most satisfying

  6. Assessment of Myocardial Triglyceride Oxidation with PET and 11C-Palmitate

    PubMed Central

    Kisrieva-Ware, Zulfia; Coggan, Andrew R.; Sharp, Terry L.; Dence, Carmen S.; Gropler, Robert J.; Herrero, Pilar

    2010-01-01

    Background The goal of this study was to test whether myocardial triglyceride (TG) turnover including oxidation of TG-derived fatty acids could be assessed with PET and 11C-palmitate. Methods and Results 26 dogs were studied fasted (FAST), during Intralipid infusion (IL), during a hyperinsulinemic-euglycemic clamp without (HIEG) or with Intralipid infusion (HIEG+IL). 11C-palmitate was injected, and 45 min were allowed for labeling of myocardial TG pool. 3-D PET data were then acquired for 60 min, with first 15 min at baseline followed by 45 min during cardiac work stimulated with constant infusion of either phenylephrine (FAST, n=6; IL, n=6; HIEG+IL, n=6) or dobutamine (FAST, n=4; HIEG, n=4). Myocardial 11C washout during adrenergic stimulation (AS) was fitted to a mono-exponential function (Km(PET)). To determine the source of this 11C clearance, Km(PET) was compared to direct coronary sinus-arterial measurements of total 11C activity, 11C-palmitate, and 11CO2. Before AS, PET curves in all groups were flat indicating absence of net clearance of 11C activity from heart. In both FAST groups, AS resulted in negligible net 11C activity and 11CO2 production higher than net 11C-palmitate uptake. AS with phenylephrine resulted in net myocardial uptake of total 11C activity and 11C-palmitate in IL and HIEG+IL, and 11CO2 production lower than 11C-palmitate uptake. In contrast, AS with dobutamine in HIEG resulted in net clearance of all 11C metabolites (total 11C activity, 11C-palmitate and 11CO2) with 11CO2 contributing 66% to endogenous FA oxidation. AS resulted in significant Km(PET) in all groups, except HIEG+IL. However, positive correlation between Km(PET) and 11CO2 was observed only in HIEG (R2=0.83, P=0.09). Conclusions This is the first study to demonstrate that using PET and pre-labeling of intracardiac TG pool with 11C-palmitate, noninvasive assessment of myocardial TG use is feasible under metabolic conditions that favor endogenous TG use such as increased

  7. Sources and build up of Zn, Cd, Cr and Pb in the sludge of Gaza.

    PubMed

    Shomar, Basem

    2009-08-01

    A comprehensive monitoring program was conducted for the sludge of Gaza between 2001 and 2006. All 32 tested parameters except zinc and adsorbable organic halogens were within the allowable values for sludge to be applied in agriculture. Average concentrations of zinc (Zn) in the sludge from the Gaza Strip for the 4 years 2002-2005 reached 2,000 mg/kg which represents a major limiting factor for sludge application in agriculture. This study aimed to measure levels of Zn in the wastewater and sludge in December 2006 and to identify the sources and the build up of Zn in the sludge in Gaza. Cd, Cr and Pb were also assessed for their relationship to sources and buildup of Zn. The results showed that there is no significant fluctuation in the concentration of Cd, Cr and Pb in the different stages of wastewater treatment. Zn, however, is concentrated inside the treatment plant by processes of precipitation and/or absorption, particularly in the aerobic facilities. Although the plant receives wastewater with Zn concentrations of only 9 microg/l, this concentration increased 18-fold inside the aerobic lagoon of the treatment plant, before dropping to an average of 14 microg/l in the effluent wastewater. The sludge from the first sedimentation pond showed a Zn concentration of 567 mg/kg and increased in the effluent polishing pond to 1,643 mg/kg. The Zn concentration in 3-month-old sludge averaged 592 mg/kg. There was no correlation between the Zn concentrations in the sludge and the wastewater at the same location. However, there was a strong correlation between Zn and Pb in the sludge. The electroplating and galvanization industries are the major Zn producing industries in Gaza, with an average Zn of 2,995 and 1,557 microg/l, respectively in their effluent wastewater. These values do not represent a significant Zn pollution load to the treatment plant because these industries are limited in size and number, and their effluents are diluted before entering the treatment

  8. Understanding the build-up of supermassive black holes and galaxies

    NASA Astrophysics Data System (ADS)

    Carrera, Francisco; Ueda, Yoshihiro; Georgakakis, Antonis

    2016-07-01

    . The excellent survey capabilities of Athena/WFI (effective area, angular resolution, field of view) will allow to measure the incidence of feedback in the shape of warm absorbers and Ultra Fast Outflows among the general population of AGN, as well as to complete the census of black hole growth by detecting and characterising significant samples of the most heavily obscured (including Compton thick) AGN, to redshifts z~3-4. The outstanding spectral throughput and resolution of Athena/X-IFU will permit measuring the energetics of those outflows to assess their influence on their host galaxies. The demographics of the heavily obscured and outflowing populations relative to their hosts are fundamental for understanding how major black hole growth events relate to the build-up of galaxies.

  9. Development of additive [11C]CO2 target system in the KOTRON-13 cyclotron and its application for [11C]radiopharmaceutical production

    NASA Astrophysics Data System (ADS)

    Moon, Byung Seok; Lee, Hong Jin; Lee, Won Kyung; Hur, Min Goo; Yang, Seung Dae; Lee, Byung Chul; Kim, Sang Eun

    2015-08-01

    The KOTRON-13 cyclotron, which was developed in South Korea for the production of medical radioisotopes, has the structural limitation of only one beam-output port, restricting the production of the carbon-11 isotope. In the present study, we investigate the design of a switchable target system and develop an effective carbon-11 target in the KOTRON-13 cyclotron, for combination with the fluorine-18 target. The target system was designed by introducing a sliding-type element between the fluorine-18 and carbon-11 targets, a tailor-made C-11 target and its cooling system. For the efficient production of [11C]CO2, the desirable target shape and internal volume were determined by a Stopping and Range of Ions in Matter (SRIM) simulation program, and the target grid was modified to resist the cavity pressure during beam irradiation. We evaluated the [11C]CO2 production while varying the material and thickness of the target foil, oxygen content of the nitrogen gas, and target loading pressure. Using sliding-type equipment including an additional gate valve and a high vacuum in a beam line, the bi-directional conversion between the fluorine-18 and carbon-11 targets was efficient regarding the accurate beam irradiation on both targets. The optimal [11C]CO2 production for 30 min irradiation at 60 μA (86.6 ± 1.7 GBq in the target at EOB) was observed at a thickness of 19 μm with HAVAR® material as a target foil and a target loading pressure of 24 bar with nitrogen plus 300 ppb of oxygen gas. Additionally, the coolant cavity system in the target grid and target chamber is useful to remove the heat transferred to the target body by the internal convection of water and thereby ensure the stability of the [11C]CO2 production under a high beam current. In the application of C-11 labeled radiopharmaceuticals such as [11C]PIB, [11C]DASB, [11C]PBR28, [11C]Methionine and [11C]Clozapine, the radiochemical yields were shown to be 25-38% (decay corrected) with over 166 GBq/μmol of

  10. Synthesis and positron emission tomographic (PET) baboon studies of [{sup 11}C]methadone and R-(-)-[{sup 11}C]methandone

    SciTech Connect

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

    1996-05-01

    Methadone (MET) maintenance has been used successfully for many years in the rehabilitation of heroin addicts. MET, a typical m{mu}-opioid receptor agonist, exists as two enantiomers and is used clinically as the racemic mixture. However, R-(-)-MET has a 10-fold higher affinity for m{mu} receptors than S-(+)-MET (IC{sub 50}: 3.0 nM and 26.4 nM, respectively) and R-(-)-MET is almost entirely responsible for the therapeutic actions of the racemate. In order to examine the pharmacokinetics and stereoselectivity of the drug, we have synthesized both [{sup 11}C]MET and R-(-)-[{sup 11}C]MET. Preparing the precursor by one-step approach to the N-demethylated methadone was precluded as other investigators cited problems with intramolecular cyclization. Therefore, a four-step synthesis using MET (or R-(-)-MET) as starting material was required to obtain the precursor, followed by a two-step radiolabeling synthesis (N-methylation followed by oxidation) to obtain [{sup 11}C]MET (or R-(-)-[{sup 11}C]MET). Comparative PET studies in the same baboon showed peak striatal uptake was 0.022%/cc at 5 minutes with a half time of clearance from peak of 100 minutes for R-(-)-[{sup 11}C]MET and a peak uptake of 0.013%/cc with a half time of 90 min for [{sup 11}C]MET. R-(-)-[{sup 11}C]MET also showed a slower disappearance in plasma. Both tracers showed higher C-11 in basal ganglia (BG), thalamus and midbrain relative to the cerebellum (CB) and occipital cortex (OC) but the BG/OC ratio was higher for R-(-)-[{sup 11}C]MET (1.3 vs 1.1). Pretreatment with naloxone (1 mg/kg, iv) increased R-(-)-[{sup 11}C]MET uptake in all brain regions whereas unlabeled MET slightly increased C-11 clearance in BG, OC and CB. These initial results show higher brain concentration and specificity of the pharmacologically active enantiomer of methadone along with significant non-specific binding.

  11. 1-/sup 11/C-2-deoxy-D-glucose and process for the preparation thereof

    DOEpatents

    MacGregor, R.R.; Wolf, A.P.; Shiue, C.Y.; Wan, C.N.

    1980-02-08

    The novel labelled compound 1-/sup 11/C-2-deoxy-D-glucose, and a process for its preparation from 2,3:4,5-di-O-isopropylidene-D-arabinitol derivatives of relatively high reactivity are disclosed. 1-/sup 11/C-2-deoxy-D-glucose is useful for measuring regional brain glucose metabolism in vivo.

  12. Effect of curing mode on the hardness of dual-cured composite resin core build-up materials.

    PubMed

    Arrais, César Augusto Galvão; Kasaz, Aline de Cerqueira; Albino, Luís Gustavo Barrote; Rodrigues, José Augusto; Reis, Andre Figueiredo

    2010-01-01

    This study evaluated the Knoop Hardness (KHN) values of two dual-cured composite resin core build-up materials and one resin cement exposed to different curing conditions. Two dual-cured core build-up composite resins (LuxaCore-Dual, DMG; and FluoroCore2, Dentsply Caulk), and one dual-cured resin cement (Rely X ARC, 3M ESPE) were used in the present study. The composite materials were placed into a cylindrical matrix (2 mm in height and 3 mm in diameter), and the specimens thus produced were either light-activated for 40 s (Optilux 501, Demetron Kerr) or were allowed to self-cure for 10 min in the dark (n = 5). All specimens were then stored in humidity at 37 degrees C for 24 h in the dark and were subjected to KHN analysis. The results were submitted to 2-way ANOVA and Tukey's post-hoc test at a pre-set alpha of 5%. All the light-activated groups exhibited higher KHN values than the self-cured ones (p = 0.00001), regardless of product. Among the self-cured groups, both composite resin core build-up materials showed higher KHN values than the dual-cured resin cement (p = 0.00001). LuxaCore-Dual exhibited higher KHN values than FluoroCore2 (p = 0.00001) when they were allowed to self-cure, while no significant differences in KHN values were observed among the light-activated products. The results suggest that dual-cured composite resin core build-up materials may be more reliable than dual-cured resin cements when curing light is not available. PMID:20658046

  13. Experimental method of in-vivo dosimetry without build-up device on the skin for external beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Jeon, Hosang; Nam, Jiho; Lee, Jayoung; Park, Dahl; Baek, Cheol-Ha; Kim, Wontaek; Ki, Yongkan; Kim, Dongwon

    2015-06-01

    Accurate dose delivery is crucial to the success of modern radiotherapy. To evaluate the dose actually delivered to patients, in-vivo dosimetry (IVD) is generally performed during radiotherapy to measure the entrance doses. In IVD, a build-up device should be placed on top of an in-vivo dosimeter to satisfy the electron equilibrium condition. However, a build-up device made of tissue-equivalent material or metal may perturb dose delivery to a patient, and requires an additional laborious and time-consuming process. We developed a novel IVD method using a look-up table of conversion ratios instead of a build-up device. We validated this method through a monte-carlo simulation and 31 clinical trials. The mean error of clinical IVD is 3.17% (standard deviation: 2.58%), which is comparable to that of conventional IVD methods. Moreover, the required time was greatly reduced so that the efficiency of IVD could be improved for both patients and therapists.

  14. Source term evaluation model for high-level radioactive waste repository with decay chain build-up.

    PubMed

    Chopra, Manish; Sunny, Faby; Oza, R B

    2016-09-18

    A source term model based on two-component leach flux concept is developed for a high-level radioactive waste repository. The long-lived radionuclides associated with high-level waste may give rise to the build-up of activity because of radioactive decay chains. The ingrowths of progeny are incorporated in the model using Bateman decay chain build-up equations. The model is applied to different radionuclides present in the high-level radioactive waste, which form a part of decay chains (4n to 4n + 3 series), and the activity of the parent and daughter radionuclides leaching out of the waste matrix is estimated. Two cases are considered: one when only parent is present initially in the waste and another where daughters are also initially present in the waste matrix. The incorporation of in situ production of daughter radionuclides in the source is important to carry out realistic estimates. It is shown that the inclusion of decay chain build-up is essential to avoid underestimation of the radiological impact assessment of the repository. The model can be a useful tool for evaluating the source term of the radionuclide transport models used for the radiological impact assessment of high-level radioactive waste repositories. PMID:27337157

  15. Measurement of excitation functions in the reactions 197Au(11C, xn)208-xAt using a radioactive 11C beam

    PubMed

    Joosten; Powell; Guo; Haustein; Larimer; McMahan; Norman; O'Neil; Rowe; VanBrocklin; Wutte; Xu; Cerny

    2000-05-29

    A light-element radioactive ion-beam capability has been developed at the LBNL 88-Inch Cyclotron. The system is based on the coupled-cyclotrons method and utilizes short-lived species, e.g., 11C, 14O, 13N produced by (p,n) and (p,alpha) reactions at the LBNL Biomedical Isotope Facility Cyclotron. In a first experiment, 197Au(11C,xn)208-xAt excitation functions have been measured for energies ranging from the Coulomb barrier up to 110 MeV using a beam of 11C with intensities up to (1-2)x10(8) ions/sec on target. The results of this experiment are compared to measurements of 197Au(12C, xn)209-xAt excitation functions. PMID:10990868

  16. PET Imaging of CRF1 with [11C]R121920 and [11C]DMP696: Is the Target of Sufficient Density?

    PubMed Central

    Sullivan, Gregory M.; Parsey, Ramin V.; Kumar, J. S. Dileep; Arango, Victoria; Kassir, Suham A.; Huang, Yung‐yu; Simpson, Norman R.; Van Heertum, Ronald L.; Mann, J. John

    2007-01-01

    Aim Overstimulation of the CRF type 1 receptor (CRF1) is implicated in anxiety and depressive disorders. The aim of this study was to investigate the in vivo binding characteristics of [11C]R121920 and [11C]DMP696 in the non‐human primate for application in positron emission tomography (PET) studies of CRF1. Methods PET imaging with the two novel CRF1 radioligands was performed in baboon. In vitro binding studies for CRF1 were performed in postmortem brain tissue of baboon and human to assess sufficiency of receptor density for PET. Results Both [11C]R121920 and [11C]DMP696 distributed rapidly and uniformly throughout brain. Washout was comparable across brain regions, without differences in volume of distribution between regions reported to have high and low in vitro CRF1 binding. Membrane‐enriched tissue homogenate assay using [125I]Tyr0‐sauvagine and specific CRF1 antagonists CP154,526 and SN003 in human occipital cortex yielded maximal binding (Bmax) of 63.3 and 147.3 fmol/mg protein, respectively, and in human cerebellar cortex yielded Bmax of 103.6 and 64.6 fmol/mg protein, respectively. Dissociation constants (KD) were subnanomolar. In baboon, specific binding was not detectable in the same regions; therefore Bmax and KD were not measurable. Autoradiographic results were consistent except there was also detectable CRF1‐specific binding in baboon cerebellum. Conclusion Neither [11C]R121920 nor [11C]DMP696 demonstrated quantifiable regional binding in vivo in baboon. In vitro results suggest CRF1 density in baboon may be insufficient for PET. Studies in man may generate more promising results due to the higher CRF1 density compared with baboon in cerebral cortex and cerebellum. PMID:17499724

  17. Understanding the uncertainty associated with particle-bound pollutant build-up and wash-off: A critical review.

    PubMed

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2016-09-15

    Accurate prediction of stormwater quality is essential for developing effective pollution mitigation strategies. The use of models incorporating simplified mathematical replications of pollutant processes is the common practice for determining stormwater quality. However, an inherent process uncertainty arises due to the intrinsic variability associated with pollutant processes, which has neither been comprehensively understood, nor well accounted for in uncertainty assessment of stormwater quality modelling. This review provides the context for defining and quantifying the uncertainty associated with pollutant build-up and wash-off on urban impervious surfaces based on the hypothesis that particle size is predominant in influencing process variability. Critical analysis of published research literature brings scientific evidence together in order to establish the fact that particle size changes with time, and different sized particles exhibit distinct behaviour during build-up and wash-off, resulting in process variability. Analysis of the different adsorption behaviour of particles confirmed that the variations in pollutant load and composition are influenced by particle size. Particle behaviour and variations in pollutant load and composition are related due to the strong affinity of pollutants such as heavy metals and hydrocarbons for specific particle size ranges. As such, the temporal variation in particle size is identified as the key to establishing a basis for assessing build-up and wash-off process uncertainty. Therefore, accounting for pollutant build-up and wash-off process variability, which is influenced by particle size, would facilitate the assessment of the uncertainty associated with modelling outcomes. Furthermore, the review identified fundamental knowledge gaps where further research is needed in relation to: (1) the aggregation of particles suspended in the atmosphere during build-up; (2) particle re-suspension during wash-off; (3) pollutant

  18. In-house development of an optimized synthetic module for routine [11C]acetate production

    PubMed Central

    Jang, Hwa Youn; Kwon, Seong Young; Pyo, Ayoung; Hur, Min Goo; Kim, Sang Wook; Park, Jeong-Hoon; Kim, Hee-Jung; Yang, Seung Dae; Lee, Sunwoo; Kim, Dong-Yeon

    2015-01-01

    [11C]Acetate, a radiotracer for PET imaging, is a promising radiopharmaceutical for overcoming the limitation of 2-deoxy-2-[18F]fluoro-d-glucose in a number of cancers. Here, the optimized automatic synthesis of [11C]acetate using an in-house-developed module under different conditions has been reported for routine production. [11C]CO2 was produced in a 16.4 MeV PETtrace cyclotron, and methyl magnesium chloride was used for synthesis. For product purification, ion-exchange solid-phase extraction cartridges were used, connected in series. High-performance liquid chromatography and gas chromatography were used to measure radiochemical and chemical purity. The Limulus amebocyte lysate test and the fluid thioglycollate medium test were performed for quality control of [11C]acetate. The total reaction time of [11C]acetate was within 15 min, and the overall decay-corrected radiochemical yield was 84.33±8.85%. Radiochemical purity was greater than 98% when evaluated on an analytical high-performance liquid chromatography system. No endotoxins or anaerobic bacteria were seen on quality control checks. Optimized production of [11C]acetate was achieved by the in-house module. Radiochemical and biological properties of the [11C]acetate produced were appropriate for clinical PET study. PMID:25244351

  19. Proton Particle Test Fluence: What's the Right Number?

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Ladbury, Raymond

    2015-01-01

    While we have been utilizing standard fluence levels such as those listed in the JESD57 document, we have begun revisiting what an appropriate test fluence is when it comes to qualifying a device for single events. Instead of a fixed fluence level or until a specific number of events occurs, a different thought process is required.

  20. Incidental finding of parathyroid adenoma with 11C-choline PET/CT.

    PubMed

    Mapelli, Paola; Busnardo, Elena; Magnani, Patrizia; Freschi, Massimo; Picchio, Maria; Gianolli, Luigi; Messa, Cristina

    2012-06-01

    Positron emission tomography/computed tomography (PET/CT) with 11C-choline is an established diagnostic tool for restaging prostate cancer patients with biochemical failure after primary treatment. In the present case, 11C-choline PET/CT was performed in a prostate cancer patient with skeletal metastases, treated with hormonal therapy. In addition to the detection of pathologic uptake at prostate and vertebra, 11C-choline uptake occurred in the neck. The finding was suggestive for a parathyroid adenoma on subsequent ultrasound, then finally confirmed by parathyroid scintigraphy and histopathological analysis performed after hemithyroidectomy. PMID:22614195

  1. On scale and magnitude of pressure build-up induced by large-scale geologic storage of CO2

    SciTech Connect

    Zhou, Q.; Birkholzer, J. T.

    2011-05-01

    The scale and magnitude of pressure perturbation and brine migration induced by geologic carbon sequestration is discussed assuming a full-scale deployment scenario in which enough CO{sub 2} is captured and stored to make relevant contributions to global climate change mitigation. In this scenario, the volumetric rates and cumulative volumes of CO{sub 2} injection would be comparable to or higher than those related to existing deep-subsurface injection and extraction activities, such as oil production. Large-scale pressure build-up in response to the injection may limit the dynamic storage capacity of suitable formations, because over-pressurization may fracture the caprock, may drive CO{sub 2}/brine leakage through localized pathways, and may cause induced seismicity. On the other hand, laterally extensive sedimentary basins may be less affected by such limitations because (i) local pressure effects are moderated by pressure propagation and brine displacement into regions far away from the CO{sub 2} storage domain; and (ii) diffuse and/or localized brine migration into overlying and underlying formations allows for pressure bleed-off in the vertical direction. A quick analytical estimate of the extent of pressure build-up induced by industrial-scale CO{sub 2} storage projects is presented. Also discussed are pressure perturbation and attenuation effects simulated for two representative sedimentary basins in the USA: the laterally extensive Illinois Basin and the partially compartmentalized southern San Joaquin Basin in California. These studies show that the limiting effect of pressure build-up on dynamic storage capacity is not as significant as suggested by Ehlig-Economides and Economides, who considered closed systems without any attenuation effects.

  2. (11)C-labeling and preliminary evaluation of vortioxetine as a PET radioligand.

    PubMed

    Andersen, Valdemar L; Hansen, Hanne D; Herth, Matthias M; Knudsen, Gitte M; Kristensen, Jesper L

    2014-06-01

    Vortioxetine is a new multi-modal drug against major depressive disorder with high affinity for a range of different serotonergic targets in the CNS. We report the (11)C-labeling of vortioxetine with [(11)C]MeI using a Suzuki-protocol that allows for the presence of an unprotected amine. Preliminary evaluation of [(11)C]vortioxetine in a Danish Landrace pig showed rapid brain uptake and brain distribution in accordance with the pharmacological profile, all though an unexpected high binding in cerebellum was also observed. [(11)C]vortioxetine displayed slow tracer kinetics with peak uptake after 60 min and with limited wash-out from the brain. Further studies are needed but this radioligand may prove to be a valuable tool in unraveling the clinical effects of vortioxetine. PMID:24786133

  3. Component build-up method for engineering analysis of missiles at low-to-high angles of attack

    NASA Technical Reports Server (NTRS)

    Hemsch, Michael J.

    1992-01-01

    Methods are presented for estimating the component build-up terms, with the exception of zero-lift drag, for missile airframes in steady flow and at arbitrary angles of attack and bank. The underlying and unifying bases of all these efforts are slender-body theory and its nonlinear extensions through the equivalent angle-of-attack concept. Emphasis is placed on the forces and moments which act on each of the fins, so that control cross-coupling effects as well as longitudinal and lateral-directional effects can be determined.

  4. LOWTHRM: a thermal fluence code. Master's thesis

    SciTech Connect

    Westbrook, C.R.

    1980-03-01

    A Fortran computer program LOWTERM is described for calculating nuclear thermal fluence incident upon a target area. Atmospheric transmissivity factors in the spectral region 0.25 to 28.5 microns are determined through use of the LOWTRAN5 computer code. The program provides a choice of six model atmospheres covering seasonal and latitudinal variations from sea level to 100 km, eight haze models, and accounts for molecular absorption, molecular scattering, and aerosol extinction. Atmospheric refraction, earth curvature effects, thermal scattering, and thermal ground reflection contributions are included.

  5. 11C-Choline and FDG PET/CT Imaging of Primary Cholangiocarcinoma: A Comparative Analysis

    PubMed Central

    Chotipanich, Chanisa; Promteangtrong, Chetsadaporn; Kunawudhi, Anchisa; Chanwat, Rawisak; Sricharunrat, Thaniya; Suratako, Savitree; Wongsa, Paramest

    2015-01-01

    Objective(s): This study aimed to compare the diagnostic values of 11C-choline and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with cholangiocarcinoma (CCA). Methods: This prospective study was conducted on 10 patients (6 males and 4 females), aged 42-69 years, suspected of having CCA based on CT or magnetic resonance imaging (MRI) results. 11C-choline and 18F-FDG PET/CT studies were performed in all patients over 1 week. PET/CT results were visually analyzed by 2 independent nuclear medicine physicians and quantitatively by calculating the tumor-to-background ratio (T/B). Results: No 11C-choline PET/CT uptake was observed in primary extrahepatic or intrahepatic CCA cases. Intense 18F-FDG avidity was detected in the tumors of 8 patients (%80). Two patients, who were 18F-FDG negative, had primary extrahepatic CCA. Ki-67 measurements were positive in all patients (range; 14.2%-39.9%). The average T/B values of 11C-choline and 18F-FDG were 0.4±0.2 and 2.0±1.0 in all cases of primary CCA, respectively; these values were significantly lower for 11C-choline (P<0.005). Both FDG and 11C-choline PET/CT detected metastatic CCA foci in all 8 patients (two patients had no metastases). Conclusion: As the results suggested, primary CCA lesions showed a poor avidity for 11C-choline, whereas 18F-FDG PET/CT was of value for the detection of most primary CCA cases. In contrast to primary lesions, metastatic CCA lesions showed 11C-choline avidity.

  6. Production and suppression of {sup 11}C in the solar neutrino experiment Borexino

    SciTech Connect

    Meindl, Quirin; Bellini, G.; Benziger, J.; Bonetti, S.; Avanzini, M. Buizza; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Carraro, C.; Chavarria, A.; Chepurnov, A.; Dalnoki-Veress, F.; D'Angelo, D.; Davini, S.; Kerret, H. de; Derbin, A.; Etenko, A.; Feilitzsch, F. von; Fomenko, K.; Franco, D.

    2011-04-27

    Cosmogenic {sup 11}C is produced in-situ by atmospheric muons and forms the main background for the measurement of solar pep- and CNO-neutrinos. However, FLUKA simulations show that the majority of {sup 11}C is accompanied by a free neutron in the final state, thus allowing for an efficient tagging method, the so-called Three-Fold Coincidence technique. The technique and its first applications on Borexino data are presented.

  7. 11C-radiolabeling study of methanol decomposition on copper oxide modified mesoporous SBA-15 silica

    NASA Astrophysics Data System (ADS)

    Tsoncheva, Tanya; Sarkadi-Priboczki, Eva

    2011-05-01

    11C-radiolabeling technique is applied to investigate methanol decomposition on copper oxide modified SBA-15. Nitrogen physisorption, XRD, FTIR, UV-vis and TPR techniques are used for catalyst characterization. Selective adsorption coverage of the catalytic active sites with 11C- and 12C-methanol molecules is carried out and the products of their conversion are followed. The mechanism of methyl formate, methylal and CO 2 formation from methanol is discussed.

  8. Serotonin 2A receptor agonist binding in the human brain with [11C]Cimbi-36

    PubMed Central

    Ettrup, Anders; da Cunha-Bang, Sophie; McMahon, Brenda; Lehel, Szabolcs; Dyssegaard, Agnete; Skibsted, Anine W; Jørgensen, Louise M; Hansen, Martin; Baandrup, Anders O; Bache, Søren; Svarer, Claus; Kristensen, Jesper L; Gillings, Nic; Madsen, Jacob; Knudsen, Gitte M

    2014-01-01

    [11C]Cimbi-36 was recently developed as a selective serotonin 2A (5-HT2A) receptor agonist radioligand for positron emission tomography (PET) brain imaging. Such an agonist PET radioligand may provide a novel, and more functional, measure of the serotonergic system and agonist binding is more likely than antagonist binding to reflect 5-HT levels in vivo. Here, we show data from a first-in-human clinical trial with [11C]Cimbi-36. In 29 healthy volunteers, we found high brain uptake and distribution according to 5-HT2A receptors with [11C]Cimbi-36 PET. The two-tissue compartment model using arterial input measurements provided the most optimal quantification of cerebral [11C]Cimbi-36 binding. Reference tissue modeling was feasible as it induced a negative but predictable bias in [11C]Cimbi-36 PET outcome measures. In five subjects, pretreatment with the 5-HT2A receptor antagonist ketanserin before a second PET scan significantly decreased [11C]Cimbi-36 binding in all cortical regions with no effects in cerebellum. These results confirm that [11C]Cimbi-36 binding is selective for 5-HT2A receptors in the cerebral cortex and that cerebellum is an appropriate reference tissue for quantification of 5-HT2A receptors in the human brain. Thus, we here describe [11C]Cimbi-36 as the first agonist PET radioligand to successfully image and quantify 5-HT2A receptors in the human brain. PMID:24780897

  9. Reference region modeling approaches for amphetamine challenge studies with [11C]FLB 457 and PET.

    PubMed

    Sandiego, Christine M; Gallezot, Jean-Dominique; Lim, Keunpoong; Ropchan, Jim; Lin, Shu-fei; Gao, Hong; Morris, Evan D; Cosgrove, Kelly P

    2015-04-01

    Detecting fluctuations in synaptic dopamine levels in extrastriatal brain regions with [(11)C]FLB 457 and positron emission tomography (PET) is a valuable tool for studying dopaminergic dysfunction in psychiatric disorders. The evaluation of reference region modeling approaches would eliminate the need to obtain arterial input function data. Our goal was to explore the use of reference region models to estimate amphetamine-induced changes in [(11)C]FLB 457 dopamine D2/D3 binding. Six healthy tobacco smokers were imaged with [(11)C]FLB 457 at baseline and at 3 hours after amphetamine (0.4 to 0.5 mg/kg, per os) administration. Simplified reference tissue models, SRTM and SRTM2, were evaluated against the 2-tissue compartmental model (2TC) to estimate [(11)C]FLB 457 binding in extrastriatal regions of interest (ROIs), using the cerebellum as a reference region. No changes in distribution volume were observed in the cerebellum between scan conditions. SRTM and SRTM2 underestimated binding, compared with 2TC, in ROIs by 26% and 9%, respectively, with consistent bias between the baseline and postamphetamine scans. Postamphetamine, [(11)C]FLB 457 binding significantly decreased across several brain regions as measured with SRTM and SRTM2; no significant change was detected with 2TC. These data support the sensitivity of [(11)C]FLB 457 for measuring amphetamine-induced dopamine release in extrastriatal regions with SRTM and SRTM2. PMID:25564239

  10. In vivo depletion of CD11c+ cells impairs scrapie agent neuroinvasion from the intestine.

    PubMed

    Raymond, Claudine R; Aucouturier, Pierre; Mabbott, Neil A

    2007-12-01

    Following oral exposure, some transmissible spongiform encephalopathy (TSE) agents accumulate first upon follicular dendritic cells (DCs) in the GALT. Studies in mice have shown that TSE agent accumulation in the GALT, in particular the Peyer's patches, is obligatory for the efficient transmission of disease to the brain. However, the mechanism through which TSE agents are initially conveyed from the gut lumen to the GALT is not known. Studies have implicated migratory hemopoietic DCs in this process, but direct demonstration of their involvement in vivo is lacking. In this study, we have investigated the contribution of CD11c(+) DCs in scrapie agent neuroinvasion through use of CD11c-diptheria toxin receptor-transgenic mice in which CD11c(+) DCs can be specifically and transiently depleted. Using two distinct scrapie agent strains (ME7 and 139A scrapie agents), we show that when CD11c(+) DCs were transiently depleted in the GALT and spleen before oral exposure, early agent accumulation in these tissues was blocked. In addition, CD11c(+) cell depletion reduced susceptibility to oral scrapie challenge indicating that TSE agent neuroinvasion from the GALT was impaired. In conclusion, these data demonstrate that migratory CD11c(+) DCs play a key role in the translocation of the scrapie agent from the gut lumen to the GALT from which neuroinvasion subsequently occurs. PMID:18025222

  11. Effects of Incident Electron Fluence and Energy on the Election Yield Curves and Emission Spectra of Dielectrics

    NASA Technical Reports Server (NTRS)

    Sim, Alec; Dennison, J. R.; Thomson, Clint

    2005-01-01

    We present an experimental study of evolution of electron emission yields and spectra as a result of internal charge build up due to electron dose. Reliable total, backscattered and secondary yield curves and electron emission spectra for un-charged insulators using a low fluence, pulsed electron beam (= or < 5 microsec at = or < 3 nA/sq mm or = or < 10(exp 5) e/sq mm per pulse) with low energy electron and UV flooding to neutralize the charging between pulses. Quantifiable changes in yield curves are observed due to < 100 fC/sq mm fluences for several excellent dielectric thin film materials. We find good agreement with a phenomenological argument based on insulator charging predicted by the yield curve; this includes an approximately linear decrease in the magnitude of the yield as incident energies approach the crossover energies and an exponential decrease in yield as accumulated internal charge reduces the landing energy to asymptotically approach a steady state surface charge and unity yield. We also find that the exponential decay of yield curves with fluence exhibit an energy dependent decay constant, alpha(E), over a broad range of incident energies below, between and above the crossover energies. Finally, we present some preliminary physics-based models for this energy dependence and attempt to relate our charging measurements to knowledge of how charge is deposited within the insulator, the mechanisms for charge trapping and transport, and how the profile of trapped charge affects the transport and emission of charges from insulators.

  12. Isotopic Dependence of GCR Fluence behind Shielding

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Wilson, John W.; Saganti, Premkumar; Kim, Myung-Hee Y.; Cleghorn, Timothy; Zeitlin, Cary; Tripathi, Ram K.

    2006-01-01

    In this paper we consider the effects of the isotopic composition of the primary galactic cosmic rays (GCR), nuclear fragmentation cross-sections, and isotopic-grid on the solution to transport models used for shielding studies. Satellite measurements are used to describe the isotopic composition of the GCR. For the nuclear interaction data-base and transport solution, we use the quantum multiple-scattering theory of nuclear fragmentation (QMSFRG) and high-charge and energy (HZETRN) transport code, respectively. The QMSFRG model is shown to accurately describe existing fragmentation data including proper description of the odd-even effects as function of the iso-spin dependence on the projectile nucleus. The principle finding of this study is that large errors (+/-100%) will occur in the mass-fluence spectra when comparing transport models that use a complete isotopic-grid (approx.170 ions) to ones that use a reduced isotopic-grid, for example the 59 ion-grid used in the HZETRN code in the past, however less significant errors (<+/-20%) occur in the elemental-fluence spectra. Because a complete isotopic-grid is readily handled on small computer workstations and is needed for several applications studying GCR propagation and scattering, it is recommended that they be used for future GCR studies.

  13. A pilot study comparing the pain sensations during PpIX build-up and clearance phases

    NASA Astrophysics Data System (ADS)

    Mikolajewska, P.; Juzeniene, A.; Iani, V.; Sollund, H.; Norsang, G.; Moan, J.

    2009-06-01

    It has been speculated that topical application of 5-aminolevulinic acid (ALA) or methyl 5-aminolevulinate (MAL) may be more painful during light exposure after longer application times of the compounds than after shorter times, even though the same levels of protoporphyrin IX (PpIX) is produced in both cases. The aim of our study was to investigate pain induction in the build-up and clearance phases of PpIX in the skin of healthy volunteers. 0.6 mmol/g of ALA (10% wt/wt) and MAL (11% wt/wt) creams were applied on the volunteers. The creams were maintained on the spots for 20- 24 hours and then wiped off. Subsequently, fresh creams were applied on the other arm of the volunteers for 4- 6 hours. Fluorescence emission spectra for all spots were measured every hour until the fluorescence levels were similar in both arms for ALA and MAL. Then the test areas were exposed to light until pain occurred. Time for pain to occur was recorded. The fluorescence of PpIX was measured before and after light exposure. PDT in the clearance phase seems to induce pain faster than in the build-up phase for ALA and MAL. Due to large interpersonal variations between volunteers further investigation is needed.

  14. Mathematical relationships for metal build-up on urban road surfaces based on traffic and land use characteristics.

    PubMed

    Gunawardena, Janaka; Ziyath, Abdul M; Egodawatta, Prasanna; Ayoko, Godwin A; Goonetilleke, Ashantha

    2014-03-01

    The study investigated the influence of traffic and land use parameters on metal build-up on urban road surfaces. Mathematical relationships were developed to predict metals originating from fuel combustion and vehicle wear. The analysis undertaken found that nickel and chromium originate from exhaust emissions, lead, copper and zinc from vehicle wear, cadmium from both exhaust and wear and manganese from geogenic sources. Land use does not demonstrate a clear pattern in relation to the metal build-up process, though its inherent characteristics such as traffic activities exert influence. The equation derived for fuel related metal load has high cross-validated coefficient of determination (Q(2)) and low Standard Error of Cross-Validation (SECV) values which indicates that the model is reliable, while the equation derived for wear-related metal load has low Q(2) and high SECV values suggesting its use only in preliminary investigations. Relative Prediction Error values for both equations are considered to be well within the error limits for a complex system such as an urban road surface. These equations will be beneficial for developing reliable stormwater treatment strategies in urban areas which specifically focus on mitigation of metal pollution. PMID:24268173

  15. A method of limiting pressure build-up in motorcycle gasoline tanks due to tank deformation in an accident

    SciTech Connect

    Erza, M.A.; Erza, A.H.

    1982-01-01

    Most motorcycle accidents are angle collisions, constituting 57% of the multi vehicle accidents. In some of these collisions, the motorcycle gasoline tank is dented, decreasing the internal volume and increasing the internal pressure. If this happens when the gasoline tank is full, or nearly full, the pressure build-up can be quite severe, blowing off the gasoline tank cap and drenching the rider with gasoline. The gasoline ofte ignites, burning the rider severely. This pressure build-up can be reduced considerably by a simple device which traps air in the tank and consists of a short tube inserted in the tank filler hole projecting downwards a short distance. This paper shows how the corresponding pressure reduction can be calculated as a function of tank volume, indentation ratio and length of tube, to enable a designer to make the necessary trade-offs in the design. This device can be easily retrofitted to an existing motorcycle gasoline tank to increase its crash worthiness.

  16. Effects of salinity build-up on the performance and bacterial community structure of a membrane bioreactor.

    PubMed

    Luo, Wenhai; Phan, Hop V; Hai, Faisal I; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2016-01-01

    This study investigated the effects of salinity increase on bacterial community structure in a membrane bioreactor (MBR) for wastewater treatment. The influent salt loading was increased gradually to simulate salinity build-up in the bioreactor during the operation of a high retention-membrane bioreactor (HR-MBR). Bacterial community diversity and structure were analyzed using 454 pyrosequencing of 16S rRNA genes of MBR mixed liquor samples. Results show that salinity increase reduced biological performance but did not affect microbial diversity in the bioreactor. Unweighted UniFrac and taxonomic analyses were conducted to relate the reduced biological performance to the change of bacterial community structure. In response to the elevated salinity condition, the succession of halophobic bacteria by halotolerant/halophilic microbes occurred and thereby the biological performance of MBR was recovered. These results suggest that salinity build-up during HR-MBR operation could be managed by allowing for the proliferation of halotolerant/halophilic bacteria. PMID:26512852

  17. Design and metrological evaluation of the new 5 MN hexapod-shaped multicomponent build-up system

    NASA Astrophysics Data System (ADS)

    Palumbo, Stefano; Germak, Alessandro; Mazzoleni, Fabrizio; Desogus, Sergio; Barbato, Giulio

    2016-06-01

    The new 5 MN hexapod-shaped multicomponent build-up system (HSM-BUS) represents significant progress in the field of reference transducers in the high force range. As with any build-up system, the presented hexapod-shaped multicomponent force transducer can lead, not only to measure forces 5 times higher than the capacity of a each single uniaxial force transducer (UFT), but gives also information about the other components of the force vector and of the moment vector. Furthermore, the calibration of such types of multicomponent force transducer regards only the calibration of the signal outputs coming from each UFT and the calibration of the geometry of the system. In this work, an a priori evaluation of the expected uncertainty is performed. As a first approximation, the effects of the calibration uncertainties of UFTs and of the geometrical tolerances given on the construction drawing were considered. Subsequently, with a finite element simulation of the mechanical behavior of the 5 MN HSM-BUS under load, a mathematical model of elastic deformations has been evaluated and applied for evaluating and correcting the systematic errors due to the deformation of the geometry under load.

  18. Comparison of L-(1-/sup 11/C)methionine and L-methyl-(/sup 11/C)methionine for measuring in vivo protein synthesis rates with PET

    SciTech Connect

    Ishiwata, K.; Vaalburg, W.; Elsinga, P.H.; Paans, A.M.; Woldring, M.G.

    1988-08-01

    To evaluate the feasibility of using either L-(1-11C)-methionine or L-(methyl-11C)methionine for measuring protein synthesis rates by positron emission tomography (PET) in normal and neoplastic tissues, distribution and metabolic studies with 14C- and 11C-labeled methionines were carried out in rats bearing Walker 256 carcinosarcoma. The tissue distributions of the two 14C-labeled methionines were similar except for liver tissue. Similar distribution patterns were observed in vivo by PET using 11C-labeled methionines. The highest 14C incorporation rate into the protein-bound fraction was found in the liver followed by tumor, brain, and pancreas. The incorporation rates in liver and pancreas were different for the two methionines. By chloroform-methanol fractionation of these four tissues, in liver significantly different amounts of 14C were observed in macromolecules. Also in brain tissue slight differences were found. By HPLC analyses of the protein-free fractions of plasma, tumor, and brain tissue at 60 min after injection, for both methionines several 14C-labeled metabolites in different amounts, were detected. About half of the 14C-labeled material in the protein-free fraction was found to be methionine. In these three tissues the amount of nonprotein metabolites and (14C)bicarbonate amount ranged from 10% to 17% and 12% to 15% for L-(1-14C)methionine and L-(methyl-14C)methionine, respectively. From these results it can be concluded that the minor metabolic pathways have to be investigated in order to quantitatively model the protein synthesis by PET.

  19. (11)C[double bond, length as m-dash]O bonds made easily for positron emission tomography radiopharmaceuticals.

    PubMed

    Rotstein, Benjamin H; Liang, Steven H; Placzek, Michael S; Hooker, Jacob M; Gee, Antony D; Dollé, Frédéric; Wilson, Alan A; Vasdev, Neil

    2016-08-22

    The positron-emitting radionuclide carbon-11 ((11)C, t1/2 = 20.3 min) possesses the unique potential for radiolabeling of any biological, naturally occurring, or synthetic organic molecule for in vivo positron emission tomography (PET) imaging. Carbon-11 is most often incorporated into small molecules by methylation of alcohol, thiol, amine or carboxylic acid precursors using [(11)C]methyl iodide or [(11)C]methyl triflate (generated from [(11)C]carbon dioxide or [(11)C]methane). Consequently, small molecules that lack an easily substituted (11)C-methyl group are often considered to have non-obvious strategies for radiolabeling and require a more customized approach. [(11)C]Carbon dioxide itself, [(11)C]carbon monoxide, [(11)C]cyanide, and [(11)C]phosgene represent alternative reactants to enable (11)C-carbonylation. Methodologies developed for preparation of (11)C-carbonyl groups have had a tremendous impact on the development of novel PET tracers and provided key tools for clinical research. (11)C-Carbonyl radiopharmaceuticals based on labeled carboxylic acids, amides, carbamates and ureas now account for a substantial number of important imaging agents that have seen translation to higher species and clinical research of previously inaccessible targets, which is a testament to the creativity, utility and practicality of the underlying radiochemistry. PMID:27276357

  20. 11C-Colchicine distribution in tissues of colchicine -sensitive and -resistant neuroblastoma xenografts

    SciTech Connect

    Mehta, B.M.; Levchenko, A.; Broussard, E.

    1995-05-01

    Multidrug resistance (MDR), a major obstacle in chemotherapy of cancer is thought to be due to the overexpression of a membrane P-glycoprotein (Pgp). P-glycoprotein acts as an energy activated efflux pump, reducing the effective drug concentrations from the MDR tumors. Our earlier studies using neuroblastoma cell lines BE(2)-C (-sensitive), and BE(2)-C/CHCb (-resistant) to colchicine (CHC), showed that uptake of 3H-CHC as well as 14C-CHC in sensitive tumors was twice as much as in resistant tumors. In view of this finding we synthesized 11C-CHC to study the distribution in xenografted animals, since 11C-CHC can be used a a Positron Emission Tomography (PET) tracer in humans. Two groups of Balb/c nude mice (5 animals each) xenografted with BE(2)-C and BE(2)-C/CHCb cells (10 x 10{sup 6} cells per animal) were injected iv retroorbitally with 200 {mu}Ci/100 {mu}l of 11C-CHC per animal. One hour after injection animals were sacrificed by cervical dislocation and blood, tissues and tumors were excised to determine the amount of radioactivity. 11C-CHC biodistribution compared well with 3H-CHC and 14C-CHC distribution. Tumor uptake in sensitive was 1.21 {plus_minus} 0.84% ID/g compared to 0.76 {plus_minus} 0.43% ID/g in resistant tumors. Tumor to blood ratios is sensitive and resistant tumors were 1.62 {plus_minus} 0.41 and 0.69 {plus_minus}0.30 respectively. 11C-Isocolchicine, a byproduct of 11C-CHC synthesis, on the other hand had only 25% uptake as compared to 11C-CHC in both sensitive and resistant tumors. We interpret these results to mean that 11C-CHC behaves similarly to other forms of CHC as a marker of the MDR phenotype. In the future, we plan to use 11C-CHC for identification of MDR status of tumors in vivo using PET scanning.

  1. Pressure Build-Up During the Fire Test in Type B(U) Packages Containing Water - 13280

    SciTech Connect

    Feldkamp, Martin; Nehrig, Marko; Bletzer, Claus; Wille, Frank

    2013-07-01

    The safety assessment of packages for the transport of radioactive materials with content containing liquids requires special consideration. The main focus is on water as supplementary liquid content in Type B(U) packages. A typical content of a Type B(U) package is ion exchange resin, waste of a nuclear power plant, which is not dried, normally only drained. Besides the saturated ion exchange resin, a small amount of free water can be included in these contents. Compared to the safety assessment of packages with dry content, attention must be paid to some more specific issues. An overview of these issues is provided. The physical and chemical compatibility of the content itself and the content compatibility with the packages materials must be demonstrated for the assessment. Regarding the mechanical resistance the package has to withstand the forces resulting from the freezing liquid. The most interesting point, however, is the pressure build-up inside the package due to vaporization. This could for example be caused by radiolysis of the liquid and must be taken into account for the storage period. If the package is stressed by the total inner pressure, this pressure leads to mechanical loads to the package body, the lid and the lid bolts. Thus, the pressure is the driving force on the gasket system regarding the activity release and a possible loss of tightness. The total pressure in any calculation is the sum of partial pressures of different gases which can be caused by different effects. The pressure build-up inside the package caused by the regulatory thermal test (30 min at 800 deg. C), as part of the cumulative test scenario under accident conditions of transport is discussed primarily. To determine the pressure, the temperature distribution in the content must be calculated for the whole period from beginning of the thermal test until cooling-down. In this case, while calculating the temperature distribution, conduction and radiation as well as evaporation

  2. The global build-up to intrinsic edge localized mode bursts seen in divertor full flux loops in JET

    NASA Astrophysics Data System (ADS)

    Chapman, S. C.; Dendy, R. O.; Todd, T. N.; Watkins, N. W.; Calderon, F. A.; Morris, J.

    2015-07-01

    A global signature of the build-up to an intrinsic edge localized mode (ELM) is found in the temporal analytic phase of signals measured in full flux azimuthal loops in the divertor region of JET. Toroidally integrating, full flux loop signals provide a global measurement proportional to the voltage induced by changes in poloidal magnetic flux; they are electromagnetically induced by the dynamics of spatially integrated current density. We perform direct time-domain analysis of the high time-resolution full flux loop signals VLD2 and VLD3. We analyze plasmas where a steady H-mode is sustained over several seconds during which all the observed ELMs are intrinsic; there is no deliberate intent to pace the ELMing process by external means. ELM occurrence times are determined from the Be II emission at the divertor. We previously [Chapman et al., Phys. Plasmas 21, 062302 (2014); Chapman et al., in 41st EPS Conference on Plasma Physics, Europhysics Conference Abstracts (European Physical Society, 2014), Vol. 38F, ISBN 2-914771-90-8] found that the occurrence times of intrinsic ELMs correlate with specific temporal analytic phases of the VLD2 and VLD3 signals. Here, we investigate how the VLD2 and VLD3 temporal analytic phases vary with time in advance of the ELM occurrence time. We identify a build-up to the ELM in which the VLD2 and VLD3 signals progressively align to the temporal analytic phase at which ELMs preferentially occur, on a ˜ 2 - 5 ms timescale. At the same time, the VLD2 and VLD3 signals become temporally phase synchronized with each other, consistent with the emergence of coherent global dynamics in the integrated current density. In a plasma that remains close to a global magnetic equilibrium, this can reflect bulk displacement or motion of the plasma. This build-up signature to an intrinsic ELM can be extracted from a time interval of data that does not extend beyond the ELM occurrence time, so that these full flux loop signals could assist in ELM

  3. Ammonia oxidation is not required for growth of Group 1.1c soil Thaumarchaeota.

    PubMed

    Weber, Eva B; Lehtovirta-Morley, Laura E; Prosser, James I; Gubry-Rangin, Cécile

    2015-03-01

    Thaumarchaeota are among the most abundant organisms on Earth and are ubiquitous. Within this phylum, all cultivated representatives of Group 1.1a and Group 1.1b Thaumarchaeota are ammonia oxidizers, and play a key role in the nitrogen cycle. While Group 1.1c is phylogenetically closely related to the ammonia-oxidizing Thaumarchaeota and is abundant in acidic forest soils, nothing is known about its physiology or ecosystem function. The goal of this study was to perform in situ physiological characterization of Group 1.1c Thaumarchaeota by determining conditions that favour their growth in soil. Several acidic grassland, birch and pine tree forest soils were sampled and those with the highest Group 1.1c 16S rRNA gene abundance were incubated in microcosms to determine optimal growth temperature, ammonia oxidation and growth on several organic compounds. Growth of Group 1.1c Thaumarchaeota, assessed by qPCR of Group 1.1c 16S rRNA genes, occurred in soil, optimally at 30°C, but was not associated with ammonia oxidation and the functional gene amoA could not be detected. Growth was also stimulated by addition of organic nitrogen compounds (glutamate and casamino acids) but not when supplemented with organic carbon alone. This is the first evidence for non-ammonia oxidation associated growth of Thaumarchaeota in soil. PMID:25764563

  4. Gatekeeper role of brain antigen-presenting CD11c+ cells in neuroinflammation.

    PubMed

    Paterka, Magdalena; Siffrin, Volker; Voss, Jan O; Werr, Johannes; Hoppmann, Nicola; Gollan, René; Belikan, Patrick; Bruttger, Julia; Birkenstock, Jérôme; Jung, Steffen; Esplugues, Enric; Yogev, Nir; Flavell, Richard A; Bopp, Tobias; Zipp, Frauke

    2016-01-01

    Multiple sclerosis is the most frequent chronic inflammatory disease of the CNS. The entry and survival of pathogenic T cells in the CNS are crucial for the initiation and persistence of autoimmune neuroinflammation. In this respect, contradictory evidence exists on the role of the most potent type of antigen-presenting cells, dendritic cells. Applying intravital two-photon microscopy, we demonstrate the gatekeeper function of CNS professional antigen-presenting CD11c(+) cells, which preferentially interact with Th17 cells. IL-17 expression correlates with expression of GM-CSF by T cells and with accumulation of CNS CD11c(+) cells. These CD11c(+) cells are organized in perivascular clusters, targeted by T cells, and strongly express the inflammatory chemokines Ccl5, Cxcl9, and Cxcl10. Our findings demonstrate a fundamental role of CNS CD11c(+) cells in the attraction of pathogenic T cells into and their survival within the CNS. Depletion of CD11c(+) cells markedly reduced disease severity due to impaired enrichment of pathogenic T cells within the CNS. PMID:26612827

  5. Brain regional pharmacokinetics of /sup 11/C-labeled diphenylhydantoin: positron emission tomography in humans

    SciTech Connect

    Baron, J.C.; Roeda, D.; Munari, C.; Crouzel, C.; Chodkiewicz, J.P.; Comar, D.

    1983-05-01

    We used positron emission tomography to study the regional cerebral pharmacokinetics of /sup 11/C-labeled diphenylhydantoin (/sup 11/C-DPH), which was given intravenously to 10 patients (8 intractable partial epileptics and 2 nonepileptics). In the nonaffected hemisphere, /sup 11/C-DPH concentration in gray matter reached equilibrium with blood within 20 minutes but was still rising at 60 minutes in white matter, where equilibrium was too slow to be detected owing to the fast physical decay of /sup 11/C. Brain-blood concentration ratios at 50 minutes were 1.37 and 1.06 in gray and white matter, respectively, similar but less variable than steady-state DPH ratios reported in human brain surgical samples. There was no indication that normal brain regions of medically resistant epileptics bind DPH less effectively than in nonepileptic patients. Brain and blood /sup 11/C-DPH concentrations were well correlated, confirming that the latter gives a reliable estimate of the former in unaffected brain regions.

  6. CD11c expression in adipose tissue and blood and its role in diet-induced obesity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine CD11c, a beta(2)-integrin, on adipose tissue (AT) leukocytes, and blood monocytes and its role in diet-induced obesity. High-fat diet-induced obese C57BL/6 mice, CD11c-deficient mice, and obese humans were studied. CD11c, leukocytes, and chemokines/cytokines were examined in AT and/or blo...

  7. Assessment of indoor absorbed gamma dose rate from natural radionuclides in concrete by the method of build-up factors.

    PubMed

    Manić, Vesna; Nikezic, Dragoslav; Krstic, Dragana; Manić, Goran

    2014-12-01

    The specific absorbed gamma dose rates, originating from natural radionuclides in concrete, were calculated at different positions of a detection point inside the standard room, as well as inside an example room. The specific absorbed dose rates corresponding to a wall with arbitrary dimensions and thickness were also evaluated, and appropriate fitting functions were developed, enabling dose rate calculation for most realistic rooms. In order to make calculation simpler, the expressions fitting the exposure build-up factors for whole (238)U and (232)Th radionuclide series and (40)K were derived in this work, as well as the specific absorbed dose rates from a point source in concrete. Calculated values of the specific absorbed dose rates at the centre point of the standard room for (238)U, (232)Th and (40)K are in the ranges of previously obtained data. PMID:24421381

  8. CMAD: A Self-consistent Parallel Code to Simulate the Electron Cloud Build-up and Instabilities

    SciTech Connect

    Pivi, M.T.F.; /SLAC

    2007-11-07

    We present the features of CMAD, a newly developed self-consistent code which simulates both the electron cloud build-up and related beam instabilities. By means of parallel (Message Passing Interface - MPI) computation, the code tracks the beam in an existing (MAD-type) lattice and continuously resolves the interaction between the beam and the cloud at each element location, with different cloud distributions at each magnet location. The goal of CMAD is to simulate single- and coupled-bunch instability, allowing tune shift, dynamic aperture and frequency map analysis and the determination of the secondary electron yield instability threshold. The code is in its phase of development and benchmarking with existing codes. Preliminary results on benchmarking are presented in this paper.

  9. Social dynamics within decomposer communities lead to nitrogen retention and organic matter build-up in soils.

    PubMed

    Kaiser, Christina; Franklin, Oskar; Richter, Andreas; Dieckmann, Ulf

    2015-01-01

    The chemical structure of organic matter has been shown to be only marginally important for its decomposability by microorganisms. The question of why organic matter does accumulate in the face of powerful microbial degraders is thus key for understanding terrestrial carbon and nitrogen cycling. Here we demonstrate, based on an individual-based microbial community model, that social dynamics among microbes producing extracellular enzymes ('decomposers') and microbes exploiting the catalytic activities of others ('cheaters') regulate organic matter turnover. We show that the presence of cheaters increases nitrogen retention and organic matter build-up by downregulating the ratio of extracellular enzymes to total microbial biomass, allowing nitrogen-rich microbial necromass to accumulate. Moreover, increasing catalytic efficiencies of enzymes are outbalanced by a strong negative feedback on enzyme producers, leading to less enzymes being produced at the community level. Our results thus reveal a possible control mechanism that may buffer soil CO2 emissions in a future climate. PMID:26621582

  10. Dosimetry of D- and L-enantiomers of /sup 11/C-labeled tryptophan and valine

    SciTech Connect

    Washburn, L.C.; Byrd, B.L.; Sun, T.T.; Crook, J.E.; Hubner, K.F.; Coffey, J.L.; Watson, E.E.

    1985-01-01

    We have previously reported the radiation dosimetry of /sup 11/C-labeled DL-tryptophan and DL-valine, as well as clinical pancreatic imaging studies with these agents. Because of significant uptake in both normal pancreas and in pancreatic tumors (thought to be due to the presence of the D-enantiomer), differential diagnosis of pancreatic carcinoma was not feasible. High-performance liquid chromatographic (HPLC) methods were developed for rapid resolution of /sup 11/C-labeled DL-tryptophan and DL-valine. Radiation dose estimates to the various organs in man were calculated for the D- and L-enantiomers of /sup 11/C-labeled tryptophan and valine, based on tissue distribution data in rats. The dose estimates were sufficiently low that 20-mCi doses of each of the enantiomeric amino acids were approved by the FDA for intravenous administration to humans. 21 refs., 3 tabs.

  11. [11C]vinpocetine: a prospective peripheral benzodiazepine receptor ligand for primate PET studies.

    PubMed

    Gulyás, Balázs; Halldin, Christer; Vas, Adám; Banati, Richard B; Shchukin, Evgeny; Finnema, Sjoerd; Tarkainen, Jari; Tihanyi, Károly; Szilágyi, Géza; Farde, Lars

    2005-03-15

    Vinpocetine, a synthetic derivative of the Vinca minor alkaloid vincamine, is a widely used drug in neurological practice. We tested the hypothesis that vinpocetine binds to peripheral benzodiazepine binding sites (PBBS) and is therefore a potential ligand of PBBS. Positron emission tomography (PET) measurements in two cynomolgous monkeys showed that pretreatment with vinpocetine markedly reduced the brain uptake of [11C]PK11195, a known PBBS radioligand. On the other hand, whereas pretreatment with PK11195 increased the brain uptake of [11C]vinpocetine due to the blockade of PBBS in the periphery, it significantly reduced the binding potential (BP) values of [11C]vinpocetine in the whole brain and in individual brain structures to PK11195. These findings indicate that, whereas the two ligands have different affinities to PBBS, vinpocetine is a potent ligand of PBBS, which in turn suggests that the pharmacological activity of vinpocetine may involve the regulation of glial functions. PMID:15760643

  12. Temperature effect on the build-up of exponentially growing polyelectrolyte multilayers. An exponential-to-linear transition point.

    PubMed

    Vikulina, Anna S; Anissimov, Yuri G; Singh, Prateek; Prokopović, Vladimir Z; Uhlig, Katja; Jaeger, Magnus S; von Klitzing, Regine; Duschl, Claus; Volodkin, Dmitry

    2016-03-21

    In this study, the effect of temperature on the build-up of exponentially growing polyelectrolyte multilayer films was investigated. It aims at understanding the multilayer growth mechanism as crucially important for the fabrication of tailor-made multilayer films. Model poly(L-lysine)/hyaluronic acid (PLL/HA) multilayers were assembled in the temperature range of 25-85 °C by layer-by-layer deposition using a dipping method. The film growth switches from the exponential to the linear regime at the transition point as a result of limited polymer diffusion into the film. With the increase of the build-up temperature the film growth rate is enhanced in both regimes; the position of the transition point shifts to a higher number of deposition steps confirming the diffusion-mediated growth mechanism. Not only the faster polymer diffusion into the film but also more porous/permeable film structure are responsible for faster film growth at higher preparation temperature. The latter mechanism is assumed from analysis of the film growth rate upon switching of the preparation temperature during the film growth. Interestingly, the as-prepared films are equilibrated and remain intact (no swelling or shrinking) during temperature variation in the range of 25-45 °C. The average activation energy for complexation between PLL and HA in the multilayers calculated from the Arrhenius plot has been found to be about 0.3 kJ mol(-1) for monomers of PLL. Finally, the following processes known to be dependent on temperature are discussed with respect to the multilayer growth: (i) polymer diffusion, (ii) polymer conformational changes, and (iii) inter-polymer interactions. PMID:26911320

  13. [11C]PiB PET in Gerstmann-Sträussler-Scheinker disease

    PubMed Central

    Deters, Kacie D; Risacher, Shannon L; Yoder, Karmen K; Oblak, Adrian L; Unverzagt, Frederick W; Murrell, Jill R; Epperson, Francine; Tallman, Eileen F; Quaid, Kimberly A; Farlow, Martin R; Saykin, Andrew J; Ghetti, Bernardino

    2016-01-01

    Gerstmann-Sträussler-Scheinker Disease (GSS) is a familial neurodegenerative disorder characterized clinically by ataxia, parkinsonism, and dementia, and neuropathologically by deposition of diffuse and amyloid plaques composed of prion protein (PrP). The purpose of this study was to evaluate if [11C]Pittsburgh Compound B (PiB) positron emission tomography (PET) is capable of detecting PrP-amyloid in PRNP gene carriers. Six individuals at risk for GSS and eight controls underwent [11C]PiB PET scans using standard methods. Approximately one year after the initial scan, each of the three asymptomatic carriers (two with PRNP P102L mutation, one with PRNP F198S mutation) underwent a second [11C]PiB PET scan. Three P102L carriers, one F198S carrier, and one non-carrier of the F198S mutation were cognitively normal, while one F198S carrier was cognitively impaired during the course of this study. No [11C]PiB uptake was observed in any subject at baseline or at follow-up. Neuropathologic study of the symptomatic individual revealed PrP-immunopositive plaques and tau-immunopositive neurofibrillary tangles in cerebral cortex, subcortical nuclei, and brainstem. PrP deposits were also numerous in the cerebellar cortex. This is the first study to investigate the ability of [11C]PiB PET to bind to PrP-amyloid in GSS F198S subjects. This finding suggests that [11C]PiB PET is not suitable for in vivo assessment of PrP-amyloid plaques in patients with GSS. PMID:27069768

  14. Influence of 11C-choline PET/CT on radiotherapy planning in prostate cancer

    PubMed Central

    López, Escarlata; Lazo, Antonio; Gutiérrez, Antonio; Arregui, Gregorio; Núñez, Isabel; Sacchetti, Antonio

    2014-01-01

    Aim To evaluate the influence of 11C-choline PET/CT on radiotherapy planning in prostate cancer patients. Background Precise information on the extension of prostate cancer is crucial for the choice of an appropriate therapeutic strategy. 11C-choline positron emission tomography (11C-choline PET/CT) has two roles in radiation oncology (RT): (1) patient selection for treatment and (2) target volume selection and delineation. In conjunction with high-accuracy techniques, it might offer an opportunity of dose escalation and better tumour control while sparing healthy tissues. Materials and methods We carried out a retrospective study in order to analyse RT planning modification based on 11C-choline PET/CT in 16 prostate cancer patients. Patients were treated with hypofractionated step-and-shoot Intensity Modulated Radiotherapy (IMRT), or Volumetric Modulated Arc Therapy (VMAT), and a daily cone-beam CT for Image Guided Radiation Therapy (IGRT). All patients underwent a 11C-choline-PET/CT scan prior to radiotherapy. Results In 37.5% of cases, a re-delineation and new dose prescription occurred. Data show good preliminary clinical results in terms of biochemical control and toxicity. No gastrointestinal (GI)/genitourinary (GU) grade III toxicities were observed after a median follow-up of 9.5 months. Conclusions In our experience, concerning the treatment of prostate cancer (PCa), 11C-choline PET/CT may be helpful in radiotherapy planning, either for dose escalation or exclusion of selected sites. PMID:25859399

  15. Bone Marrow CD11c+ Cell-Derived Amphiregulin Promotes Pulmonary Fibrosis.

    PubMed

    Ding, Lin; Liu, Tianju; Wu, Zhe; Hu, Biao; Nakashima, Taku; Ullenbruch, Matthew; Gonzalez De Los Santos, Francina; Phan, Sem H

    2016-07-01

    Amphiregulin (AREG), an epidermal growth factor receptor ligand, is implicated in tissue repair and fibrosis, but its cellular source and role in regeneration versus fibrosis remain unclear. In this study, we hypothesize that AREG induced in bone marrow-derived CD11c(+) cells is essential for pulmonary fibrosis. Thus, the objectives were to evaluate the importance and role of AREG in pulmonary fibrosis, identify the cellular source of AREG induction, and analyze its regulation of fibroblast function and activation. The results showed that lung AREG expression was significantly induced in bleomycin-induced pulmonary fibrosis. AREG deficiency in knockout mice significantly diminished pulmonary fibrosis. Analysis of AREG expression in major lung cell types revealed induction in fibrotic lungs predominantly occurred in CD11c(+) cells. Moreover, depletion of bone marrow-derived CD11c(+) cells suppressed both induction of lung AREG expression and pulmonary fibrosis. Conversely, adoptive transfer of bone marrow-derived CD11c(+) cells from bleomycin-treated donor mice exacerbated pulmonary fibrosis, but not if the donor cells were made AREG deficient prior to transfer. CD11c(+) cell-conditioned media or coculture stimulated fibroblast proliferation, activation, and myofibroblast differentiation in an AREG-dependent manner. Furthermore, recombinant AREG induced telomerase reverse transcriptase, which appeared to be essential for the proliferative effect. Finally, AREG significantly enhanced fibroblast motility, which was associated with increased expression of α6 integrin. These findings suggested that induced AREG specifically in recruited bone marrow-derived CD11c(+) cells promoted bleomycin-induced pulmonary fibrosis by activation of fibroblast telomerase reverse transcriptase-dependent proliferation, motility, and indirectly, myofibroblast differentiation. PMID:27206766

  16. New developments of 11C post-accelerated beams for hadron therapy and imaging

    NASA Astrophysics Data System (ADS)

    Augusto, R. S.; Mendonca, T. M.; Wenander, F.; Penescu, L.; Orecchia, R.; Parodi, K.; Ferrari, A.; Stora, T.

    2016-06-01

    Hadron therapy was first proposed in 1946 and is by now widespread throughout the world, as witnessed with the design and construction of the CNAO, HIT, PROSCAN and MedAustron treatment centres, among others. The clinical interest in hadron therapy lies in the fact that it delivers precision treatment of tumours, exploiting the characteristic shape (the Bragg peak) of the energy deposition in the tissues for charged hadrons. In particular, carbon ion therapy is found to be biologically more effective, with respect to protons, on certain types of tumours. Following an approach tested at NIRS in Japan [1], carbon ion therapy treatments based on 12C could be combined or fully replaced with 11C PET radioactive ions post-accelerated to the same energy. This approach allows providing a beam for treatment and, at the same time, to collect information on the 3D distributions of the implanted ions by PET imaging. The production of 11C ion beams can be performed using two methods. A first one is based on the production using compact PET cyclotrons with 10-20 MeV protons via 14N(p,α)11C reactions following an approach developed at the Lawrence Berkeley National Laboratory [2]. A second route exploits spallation reactions 19F(p,X)11C and 23Na(p,X)11C on a molten fluoride salt target using the ISOL (isotope separation on-line) technique [3]. This approach can be seriously envisaged at CERN-ISOLDE following recent progresses made on 11C+ production [4] and proven post-acceleration of pure 10C3/6+ beams in the REX-ISOLDE linac [5]. Part of the required components is operational in radioactive ion beam facilities or commercial medical PET cyclotrons. The driver could be a 70 MeV, 1.2 mA proton commercial cyclotron, which would lead to 8.1 × 10711C6+ per spill. This intensity is appropriate using 11C ions alone for both imaging and treatment. Here we report on the ongoing feasibility studies of such approach, using the Monte Carlo particle transport code FLUKA [6,7] to simulate

  17. 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.

  18. Concurrent Monte Carlo transport and fluence optimization with fluence adjusting scalable transport Monte Carlo

    PubMed Central

    Svatos, M.; Zankowski, C.; Bednarz, B.

    2016-01-01

    Purpose: The future of radiation therapy will require advanced inverse planning solutions to support single-arc, multiple-arc, and “4π” delivery modes, which present unique challenges in finding an optimal treatment plan over a vast search space, while still preserving dosimetric accuracy. The successful clinical implementation of such methods would benefit from Monte Carlo (MC) based dose calculation methods, which can offer improvements in dosimetric accuracy when compared to deterministic methods. The standard method for MC based treatment planning optimization leverages the accuracy of the MC dose calculation and efficiency of well-developed optimization methods, by precalculating the fluence to dose relationship within a patient with MC methods and subsequently optimizing the fluence weights. However, the sequential nature of this implementation is computationally time consuming and memory intensive. Methods to reduce the overhead of the MC precalculation have been explored in the past, demonstrating promising reductions of computational time overhead, but with limited impact on the memory overhead due to the sequential nature of the dose calculation and fluence optimization. The authors propose an entirely new form of “concurrent” Monte Carlo treat plan optimization: a platform which optimizes the fluence during the dose calculation, reduces wasted computation time being spent on beamlets that weakly contribute to the final dose distribution, and requires only a low memory footprint to function. In this initial investigation, the authors explore the key theoretical and practical considerations of optimizing fluence in such a manner. Methods: The authors present a novel derivation and implementation of a gradient descent algorithm that allows for optimization during MC particle transport, based on highly stochastic information generated through particle transport of very few histories. A gradient rescaling and renormalization algorithm, and the

  19. (/sup 11/C)clorgyline and (/sup 11/C)-L-deprenyl and their use in measuring functional monoamine oxidase activity in the brain using positron emission tomography

    DOEpatents

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

    1986-04-17

    This invention involves a new strategy for imaging the activity of the enzyme monoamine oxidase in the living body by using /sup 11/C-labeled enzyme inhibitors which bind irreversibly to an enzyme as a result of catalysis. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  20. Improved sensitivity of human brain MAO B measurement using deuterium substituted [{sup 11}C]L-deprenyl ([{sup 11}C]L-deprenyl-D2)

    SciTech Connect

    Fowler, J.S.; Volkow, N.D.; Wang, G.J.

    1995-05-01

    Post-mortem reports that human brain monoamine oxidase B (MAO B) increases in normal aging and neurodegenerative disorders due to the proliferation of MAO B-rich glial cells suggest that PET measures of MAO B may track gliosis. We have recently shown that the MAO B tracer [{sup 11}C]L-deprenyl has limited sensitivity in regions of high MAO B due to its rapid rate of trapping. This limits its utility for measuring MAO B in brain regions where MAO B is higher and/or where blood flow is low. We have recently demonstrated that [{sup 11}C]L-deprenyl-D2 has improved sensitivity in regions of high MAO B due to the deuterium isotope effect which reduces the rate of trapping. We report studies [{sup 11}C]L-deprenyl-D2 in normal human brain in 16 healthy men and women (age range 23-73) to assess tracer sensitivity, regional distribution, and reproducibility. Graphical analysis for irreversible systems was used to calculate Ki (influx constant) as an index of MAO B concentration in different brain regions. The uptake of carbon-11 in different brain regions was rapid, peaking at 5 minutes and plateauing from 30-60 minutes after an initial clearance. MAO B was highest in subcortical regions: thalamus{ge}basal ganglia>cingulate gyrus>frontal cortex=occipital cortex=cerebellum in agreement with post-mortem measurements. Ki values were highly correlated within an individual. Repeated measures at 1-4 week intervals were highly correlated (r=0.9; p=0.0001). In women (n=8: age range 23-73), Ki increased with increasing age for 8 brain regions (p < 0.04). Though men (N=8; age range 34-70) showed no correlation with age, a larger sample size is needed to adequately assess trends. In summary, the use of [{sup 11}C]L-deprenyl-D2 improves the measurement of MAO B in the human brain permitting its investigation as a positive tracer for glial cell proliferation in neurodegenerative disorders.

  1. Building Up the Benefits

    MedlinePlus

    ... by walking to your nearby grocery store. Switch electric appliances for muscle- powered versions, such as the can opener, lawn mower, or rake. VISIT www.nia.nih.gov/Go4Life l Read more tips. l Print useful tools. l Order a free exercise guide or DVD. ...

  2. Building up College Towns

    ERIC Educational Resources Information Center

    Powers, Elia

    2007-01-01

    When it comes to college towns and neighborhoods near urban campuses, quaint will not cut it anymore. An increasing number of institutions are finding ways--directly or indirectly--to promote a mix of commercial and residential development just beyond their borders that they hope will lure students and faculty. This article discusses how…

  3. Effects of Ketoconazole on the Biodistribution and Metabolism of [11C]Loperamide and [11C]N-Desmethyl-loperamide in Wild-type and P-gp Knockout Mice

    PubMed Central

    Seneca, Nicholas; Zoghbi, Sami S.; Shetty, H. Umesha; Tuan, Edward; Kannan, Pavitra; Taku, Andrew; Innis, Robert B.; Pike, Victor W.

    2010-01-01

    Introduction [11C]Loperamide and [11C]N-desmethyl-loperamide ([11C]dLop) have been proposed as radiotracers for imaging brain P-glycoprotein (P-gp) function. A major route of [11C]loperamide metabolism is N-demethylation to [11C]dLop. We aimed to test whether inhibition of CYP3A4 with ketoconazole might reduce the metabolism of [11C]loperamide and [11C]dLop in mice, and thereby improve the quality of these radiotracers. Methods Studies were performed in wild-type and P-gp knockout (mdr–1a/b −/−) mice. During each of seven study sessions, one pair of mice, comprising one wild-type and one knockout mouse, waspretreated with ketoconazole (50 mg/kg, i.p.) while another such pair was left untreated. Mice were sacrificed at 30 min after injection of [11C]loperamide or [11C]dLop. Whole brain and plasma samples were measured for radioactivity and analyzed with radio-HPLC. Results Ketoconazole increased the plasma concentrations of [11C]loperamide and its main radiometabolite, [11C]dLop, by about two-fold in both wild-type and knockout mice, whereas the most polar radiometabolite was decreased three-fold. Furthermore, ketoconazole increased the brain concentrations of [11C]loperamide and the radiometabolite [11C]dLop by about two-fold in knockout mice, and decreased the brain concentrations of the major and most polar radiometabolite in wild-type and knockout mice by 82 and 49%, respectively. In contrast, ketoconazole had no effect on plasma and brain distribution of administered [11C]dLop and its radiometabolites in either wild-type or knockout mice, except to increase the low plasma [11C]dLop concentration. The least polar radiometabolite of [11C]dLop was identified with LC-MSn as the N-hydroxymethyl analog of [11C]dLop and this also behaved as a P-gp substrate. Conclusion In this study, ketoconazole (50 mg/kg, i.p.) proved partiallyeffective for inhibiting the N-demethylation of [11C]loperamide in mouse in vivo but had relatively smaller or no effect on [11C

  4. [(11)C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain.

    PubMed

    Visser, Anniek K D; Ramakrishnan, Nisha K; Willemsen, Antoon T M; Di Gialleonardo, Valentina; de Vries, Erik F J; Kema, Ido P; Dierckx, Rudi A J O; van Waarde, Aren

    2014-01-01

    The PET tracer [(11)C]5-hydroxytryptophan ([(11)C]5-HTP), which is converted to [(11)C]5-hydroxytryptamine ([(11)C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [(11)C]5-HTP in rat? Male rats were scanned with [(11)C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [(11)C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [(11)C]5-HTP uptake, and the k3. This was unexpected as NSD 1015 directly inhibits the enzyme converting [(11)C]5-HTP to [(11)C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [(11)C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents. PMID:24084697

  5. Expression of CD11c Is Associated with Unconventional Activated T Cell Subsets with High Migratory Potential

    PubMed Central

    Cantero, Jon; Tarrats, Antoni; Fernández, Marco Antonio; Sumoy, Lauro; Rodolosse, Annie; McSorley, Stephen J.

    2016-01-01

    CD11c is an α integrin classically employed to define myeloid dendritic cells. Although there is little information about CD11c expression on human T cells, mouse models have shown an association of CD11c expression with functionally relevant T cell subsets. In the context of genital tract infection, we have previously observed increased expression of CD11c in circulating T cells from mice and women. Microarray analyses of activated effector T cells expressing CD11c derived from naïve mice demonstrated enrichment for natural killer (NK) associated genes. Here we find that murine CD11c+ T cells analyzed by flow cytometry display markers associated with non-conventional T cell subsets, including γδ T cells and invariant natural killer T (iNKT) cells. However, in women, only γδ T cells and CD8+ T cells were enriched within the CD11c fraction of blood and cervical tissue. These CD11c+ cells were highly activated and had greater interferon (IFN)-γ secretory capacity than CD11c- T cells. Furthermore, circulating CD11c+ T cells were associated with the expression of multiple adhesion molecules in women, suggesting that these cells have high tissue homing potential. These data suggest that CD11c expression distinguishes a population of circulating T cells during bacterial infection with innate capacity and mucosal homing potential. PMID:27119555

  6. Astronomical forcing of an exceptionally long Sahel wet phase during Marine Isotope Stage 11c

    NASA Astrophysics Data System (ADS)

    Prange, Matthias; Rachmayani, Rima; Schulz, Michael

    2016-04-01

    Increased rainfall and expanded vegetation over North Africa during the early-to-mid Holocene was related to an intensified West African monsoon and a northward displacement of the monsoon trough triggered by astronomical forcing. Similar wet phases are evidenced for earlier interglacials including Marine Isotope Stage (MIS) 11c (ca. 425-395 ka before present). We performed a series of time slice simulations using the comprehensive coupled climate model CCSM3 including a dynamic vegetation module in order to examine the dynamics of the MIS 11c humid period. Proxy records from a marine sediment core site off Northwest Africa suggest an extremely long Sahel/Sahara wet phase during MIS 11c between ca. 420 and 405 ka ago, revealing that North African rainfall changes did not simply follow local summer insolation. Instead, the climate model simulations suggest an important role of the obliquity-driven intra-hemispheric insolation gradient in forcing Sahelian rainfall changes. The specific phasing between precession and obliquity during the MIS 11c interglacial resulted in the exceptionally long wet phase in the Sahel region. The early part of this wet phase was primarily induced by northern-hemispheric differential warming in response to maximum obliquity around 416 ka before present. As such, this interval may well serve as an analog for potential future Sahel rainfall increase induced by strong northern hemisphere extratropical warming.

  7. 29 CFR 1977.5 - Persons protected by section 11(c).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Persons protected by section 11(c). 1977.5 Section 1977.5 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) DISCRIMINATION AGAINST EMPLOYEES EXERCISING RIGHTS UNDER THE WILLIAMS-STEIGER OCCUPATIONAL SAFETY AND HEALTH ACT OF...

  8. 8Be and 9B nuclei in dissociation of relativistic 10B and 11C nuclei

    NASA Astrophysics Data System (ADS)

    Artemenkov, D. A.; Bradnova, V.; Firu, E.; Kornegrutsa, N. K.; Haiduc, M.; Mamatkulov, K. Z.; Kattabekov, R. R.; Neagu, A.; Rukoyatkin, P. A.; Rusakova, V. V.; Stanoeva, R.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2016-02-01

    Progress in the study of nuclear clustering in the relativistic 10B and 11C nuclei dissociation in nuclear track emulsion is presented. The contribution of the unbound 8Be and 9B nuclei to their structure is determined on the basis of measurements of the emission angles of relativistic He and H fragments.

  9. 8Be and 9B nuclei in dissociation of relativistic 10C and 11C nuclei

    NASA Astrophysics Data System (ADS)

    Artemenkov, D. A.; Bradnova, V.; Firu, E.; Kornegrutsa, N. K.; Haiduc, M.; Mamatkulov, K. Z.; Kattabekov, R. R.; Neagu, A.; Rukoyatkin, P. A.; Rusakova, V. V.; Stanoeva, R.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2016-05-01

    Progress in the study of nuclear clustering in the relativistic 10C and 11C nuclei dissociation in nuclear track emulsion is presented. The contribution of the unbound 8Be and 9B nuclei to their structure is determined on the basis of measurements of the emission angles of relativistic He and H fragments.

  10. ATP11C Facilitates Phospholipid Translocation across the Plasma Membrane of All Leukocytes

    PubMed Central

    Yabas, Mehmet; Jing, Weidong; Shafik, Sarah

    2016-01-01

    Organization of the plasma membrane into specialized substructures in different blood lineages facilitates important biological functions including proper localization of receptors at the plasma membrane as well as the initiation of crucial intracellular signaling cascades. The eukaryotic plasma membrane is a lipid bilayer that consists of asymmetrically distributed phospholipids. This asymmetry is actively maintained by membrane-embedded lipid transporters, but there is only limited data available about the molecular identity of the predominantly active transporters and their substrate specificity in different leukocyte subsets. We demonstrate here that the P4-type ATPase ATP11C mediates significant flippase activity in all murine leukocyte subsets. Loss of ATP11C resulted in a defective internalization of phosphatidylserine (PS) and phosphatidylethanolamine (PE) in comparison to control cells. The diminished flippase activity caused increased PS exposure on 7-aminoactinomycin D− (7-AAD−) viable pro-B cells freshly isolated from the bone marrow of ATP11C-deficient mice, which was corrected upon a 2-hour resting period in vitro. Despite the impaired flippase activity in all immune cell subsets, the only other blood cell type with an accumulation of PS on the surface were viable 7-AAD− developing T cells but this did not result in any discernable effect on their development in the thymus. These findings show that all leukocyte lineages exhibit flippase activity, and identify ATP11C as an aminophospholipid translocase in immune cells. PMID:26799398

  11. 29 CFR 1977.3 - General requirements of section 11(c) of the Act.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false General requirements of section 11(c) of the Act. 1977.3 Section 1977.3 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) DISCRIMINATION AGAINST EMPLOYEES EXERCISING RIGHTS UNDER...

  12. 29 CFR 1977.5 - Persons protected by section 11(c).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false Persons protected by section 11(c). 1977.5 Section 1977.5 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) DISCRIMINATION AGAINST EMPLOYEES EXERCISING RIGHTS UNDER THE...

  13. 29 CFR 1977.3 - General requirements of section 11(c) of the Act.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false General requirements of section 11(c) of the Act. 1977.3 Section 1977.3 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) DISCRIMINATION AGAINST EMPLOYEES EXERCISING RIGHTS UNDER...

  14. PET evaluation of spinal cord tumor using sup 11 C-methionine

    SciTech Connect

    Higano, S.; Shishido, F.; Nagashima, M.; Tomura, N.; Murakami, M.; Inugami, A.; Fujita, H.; Tabata, K.; Yasui, N.; Uemura, K. )

    1990-03-01

    A cervical cord tumor was examined with positron emission tomography using L-methyl-({sup 11}C)methionine. The radioactive tracer accumulated in the solid parts (but not in the associated cysts) of the neoplasm, which at histology was found to be an ependymoma.

  15. Charge topology of the coherent dissociation of relativistic {sup 11}C and {sup 12}N nuclei

    SciTech Connect

    Artemenkov, D. A.; Bradnova, V.; Zaitsev, A. A.; Zarubin, P. I. Zarubina, I. G.; Kattabekov, R. R.; Kornegrutsa, N. K.; Mamatkulov, K. Z.; Rukoyatkin, P. A.; Rusakova, V. V.; Stanoeva, R.

    2015-09-15

    The charge topology of coherent-dissociation events is presented for {sup 11}C and {sup 12}N nuclei of energy 1.2 GeV per nucleon bombarding nuclear track emulsions. This topology is compared with respective data for {sup 7}Be, {sup 8,10}B, {sup 9,10}C, and {sup 14}N nuclei.

  16. Functional role of CD11c+ monocytes in atherogenesis associated with hypercholesterolemia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monocyte activation and migration into the arterial wall are key events in atherogenesis associated with hypercholesterolemia. CD11c/CD18, a beta2 integrin expressed on human monocytes and a subset of mouse monocytes, has been shown to play a distinct role in human monocyte adhesion on endothelial c...

  17. Photonuclear target systems for producing clinically useful quantities of 11C using an electron linear accelerator.

    PubMed

    Piltingsrud, H V; Robbins, P J

    1985-01-01

    Described in this paper are what we believe to be the first practical photonuclear target systems for production of 11C containing CO and CO2 using bremsstrahlung produced from an electron linear accelerator similar to certain radiotherapy accelerators. This is a continuation of work reported earlier concerning a similar target system presently being used for production of 15O-O2. The 11C producing systems utilized liquid carbon dioxide, liquid cyclohexane, and liquid glacial acetic acid target materials. The carbon dioxide and glacial acetic acid target materials produced principally a 11C-CO product material. The cyclohexane target material produced a 11C-hydrocarbon product which was then oxidized to CO2. Target activity yields for these systems, normalized to a 20-cm-long by 10-cm-diam target chamber irradiated in a bremsstrahlung field produced by a 26-MeV, 100-microA electron beam, were 1.9 X 10(8) Bq (5 mCi) at 7.4 X 10(8) Bq g-1 (20 mCi g-1) for carbon dioxide, 1.4 X 10(8) Bq (3.8 mCi) at 3.7 X 10(10) Bq g-1 (1 Ci g-1) for cyclohexane, and 7.4 X 10(8) Bq (20 mCi) at 3.7 X 10(10) Bq g-1 (1 Ci g-1) for glacial acetic acid. PMID:3930932

  18. Basis for equivalent fluence concept in space solar cells

    NASA Technical Reports Server (NTRS)

    Meulenberg, A.

    1982-01-01

    The equivalent fluence concept is defined, and its use and potential problems are noted. Silicon and GaAs solar cells are compared in a radiation environment. The analysis indicates that valid equivalent fluence values may be easier to obtain in GaAs than in silicon.

  19. Neutron detector simultaneously measures fluence and dose equivalent

    NASA Technical Reports Server (NTRS)

    Dvorak, R. F.; Dyer, N. C.

    1967-01-01

    Neutron detector acts as both an area monitoring instrument and a criticality dosimeter by simultaneously measuring dose equivalent and fluence. The fluence is determined by activation of six foils one inch below the surface of the moderator. Dose equivalent is determined from activation of three interlocked foils at the center of the moderator.

  20. Reactor vessel fluence evaluation and dosimetry

    SciTech Connect

    Lois, L. )

    1992-01-01

    The methodology currently in use for the estimation of the fast neutron fluence to the pressure vessel (inside surface and reactor cavity) is based on discrete ordinates two-dimensional codes such as DOT or its updated version DORT. This methodology assumes a P[sub 3] scattering, an S[sub 8] quadrature approximation, and cross sections based on the ENDF/B-IV file. Associated one-dimensional codes are often used for the cross-section collapsing portion of the calculation. The neutron spectrum at the pressure vessel location of interest is estimated assuming a [sup 235]U, [sup 239]Pu, or [sup 241]Pu source spectrum or an appropriate combination thereof. The two-dimensional codes and associated methodologies were benchmarked in the early eighties using the results of the PCA and PSF Oak Ridge National Laboratory reactor experiments. The benchmarking experiments were estimated to provide an uncertainty of [approx]10%. The results of the calculations applied to a reactor were estimated to have an uncertainty of [approx]20%. This level of uncertainty was assumed in the estimation of the margin term defined in 10CFR50.61

  1. NOTE: Comparison of sources of exit fluence variation for IMRT

    NASA Astrophysics Data System (ADS)

    Gardner, Joseph K.; Clews, Luke; Gordon, J. James; Wang, Song; Greer, Peter B.; Siebers, Jeffrey V.

    2009-10-01

    The fluence exiting a patient during beam delivery can be used as treatment delivery quality assurance, either by direct comparison with expected exit fluences or by backprojection to reconstruct the patient dose. Multiple possible sources of measured exit fluence deviations exist, including changes in the beam delivery and changes in the patient anatomy. The purpose of this work is to compare the deviations caused by these sources. Machine delivery-related variability is measured by acquiring multiple dosimetric portal images (DPIs) of several test fields without a patient/phantom in the field over a time period of 2 months. Patient anatomy-related sources of fluence variability are simulated by computing transmission DPIs for a prostate patient using the same incident fluence for 11 different computed tomography (CT) images of the patient anatomy. The standard deviation (SD) and maximum deviation of the exit fluence, averaged over 5 mm × 5 mm square areas, is calculated for each test set. Machine delivery fluence SDs as large as 1% are observed for a sample patient field and as large as 2.5% for a picket-fence dMLC test field. Simulations indicate that day-to-day patient anatomy variations induce exit fluence SDs as large as 3.5%. The largest observed machine delivery deviations are 4% for the sample patient field and 7% for the picket-fence field, while the largest difference for the patient anatomy-related source is 8.5%. Since daily changes in patient anatomy can result in substantial exit fluence deviations, care should be taken when applying fluence back-projection to ensure that such deviations are properly attributed to their source.

  2. SU-E-T-59: Calculations of Collimator Scatter Factors (Sc) with and Without Custom-Made Build-Up Caps for CyberKnife

    SciTech Connect

    Wokoma, S; Yoon, J; Jung, J; Lee, S

    2014-06-01

    Purpose: To investigate the impact of custom-made build-up caps for a diode detector in robotic radiosurgery radiation fields with variable collimator (IRIS) for collimator scatter factor (Sc) calculation. Methods: An acrylic cap was custom-made to fit our SFD (IBA Dosimetry, Germany) diode detector. The cap has thickness of 5 cm, corresponding to a depth beyond electron contamination. IAEA phase space data was used for beam modeling and DOSRZnrc code was used to model the detector. The detector was positioned at 80 cm source-to-detector distance. Calculations were performed with the SFD, with and without the build-up cap, for clinical IRIS settings ranging from 7.5 to 60 mm. Results: The collimator scatter factors were calculated with and without 5 cm build-up cap. They were agreed within 3% difference except 15 mm cone. The Sc factor for 15 mm cone without buildup was 13.2% lower than that with buildup. Conclusion: Sc data is a critical component in advanced algorithms for treatment planning in order to calculate the dose accurately. After incorporating build-up cap, we discovered differences of up to 13.2 % in Sc factors in the SFD detector, when compared against in-air measurements without build-up caps.

  3. Measurements and simulation of the radiation build-up process in a prebunched free-electron maser oscillator

    SciTech Connect

    Gilutin, L.; Pinhasi, Y.; Cohen, M.

    1995-12-31

    Numerical studies of the radiation buildup process in a prebunched free-electron maser oscillator (FEM), were carried out at Tel-Aviv University (TAU) and at the University of Maryland (UMD), and compared to the experimental measurements taken on the prebunched beam FEM experiments in TAU. We present measurements of the temporal evolution of radiation excited from noise until a steady-state operation is established. The evolution of the spectral characteristics of the radiation was investigated using the data collected by a fast digitizing scope, which recorded the IF signal obtained from heterodyning the laser radiation with a stable local oscillator. The mode competition process was observed. The experimental results were compared to analytical calculations of the spontaneous emission power and small-signal gain. Nonlinear {open_quote}amplifier{close_quote} simulation codes were employed for calculation of the extraction efficiency and saturation power. Multi-frequency simulations of the mode competition process were carried out using simulation (MALT ID) code, which is based on a space-time one-dimensional model of a free-electron laser oscillator. Conditions for establishment of single-(longitudinal) mode operation were identified and compared to the experimental measurements. Prebunching of the e-beam current permits external interference in the mode competition and coherence build-up process. We found experimentally and confirmed numerically that prebunching can determine the frequency of oscillation if the e-beam is injected with a sufficient bunching power, and shortens the oscillation buildup and coherence establishment time.

  4. Effect of the thermoplastic masks on dose distribution in the build-up region for photon beams

    NASA Astrophysics Data System (ADS)

    Półtorak, Michał; Fujak, Edyta; Kukołowicz, Paweł

    2016-03-01

    The aim of the study was to investigate the influence of thermoplastic masks material (Klarity Medical&Equipment Co., Guangzhou, China) with different diameters of holes (ϕ 0.25 cm and ϕ 0.40 cm) on the dose distribution in the build-up region for photon beams. Measurements were made for external radiation beams produced by the linear accelerator (TrueBeam, Varian Medical Systems, Inc., Palo Alto, CA, USA) using the Markus parallel plane ionization chamber and the Unidos electrometer (both from PTW, Freiburg, Germany). Measurements were made in a solid water phantom for two photon energies 6 MV and 15 MV, at 90 cm source to skin distance, for four fields of 5 cm × 5 cm, 10 cm × 10 cm, 15 cm × 15 cm and 20 cm × 20 cm. Compared to the open field, the maximum dose with mask was closer to the surface of the phantom by about 1.4 mm and 1.2 mm for 6 MV and 15 MV X-Rays, respectively. The surface dose increase from 10% to 42% for 6 MV and from 5% to 28% for 15 MV X-Rays.

  5. Impurities build up and behavior of low organic bauxite of Panchpatmali bauxite mines of Nalco in the Bayer process

    SciTech Connect

    Chattopadhyay, D.K.; Satpathy, B.K.; Mohanty, R.C.

    1996-10-01

    The major portions of the impurity enter the Bayer process through bauxite. Beyond the critical levels the impurities alter the kinetics of the process. Among the various impurities, organic carbon is the most prominent one that affects the precipitation operation and the product quality, depending on the level of organic with respect to the precipitation process adopted. A lower level of less than 0.2% organic carbon in the Panchpatmali bauxite of Nalco although has allowed smooth operation of the plant for the last seven years, the same has been a matter of concern today. The present paper has analyzed the situation at Nalco plant with respect to various impurities build up over the years. The occurrence of organic in bauxite and its behavior in the Bayer process has been analyzed. Even such low level organic has been a point of watch for achieving productivity and quality product. The paper also highlights how the problems of sodium oxalate, emerging from the organic, has been resolved at Nalco with help of Aluminum Pechiney, France. Results are supported with experiments, plant data and characterization of bauxite and hydrates through instrumental techniques.

  6. Social dynamics within decomposer communities lead to nitrogen retention and organic matter build-up in soils

    PubMed Central

    Kaiser, Christina; Franklin, Oskar; Richter, Andreas; Dieckmann, Ulf

    2015-01-01

    The chemical structure of organic matter has been shown to be only marginally important for its decomposability by microorganisms. The question of why organic matter does accumulate in the face of powerful microbial degraders is thus key for understanding terrestrial carbon and nitrogen cycling. Here we demonstrate, based on an individual-based microbial community model, that social dynamics among microbes producing extracellular enzymes (‘decomposers') and microbes exploiting the catalytic activities of others (‘cheaters') regulate organic matter turnover. We show that the presence of cheaters increases nitrogen retention and organic matter build-up by downregulating the ratio of extracellular enzymes to total microbial biomass, allowing nitrogen-rich microbial necromass to accumulate. Moreover, increasing catalytic efficiencies of enzymes are outbalanced by a strong negative feedback on enzyme producers, leading to less enzymes being produced at the community level. Our results thus reveal a possible control mechanism that may buffer soil CO2 emissions in a future climate. PMID:26621582

  7. Studies of E-Cloud Build up for the FNAL Main Injector and for theLHC

    SciTech Connect

    Furman, M.A.

    2006-06-14

    We present a summary of recent simulation studies of the electron-cloud (EC) build-up for the FNAL MI and for the LHC. In the first case we pay particular attention to the dependence on bunch intensity N{sub b} at injection energy assuming the nominal bunch spacing t{sub b} = 19 ns, and we focus on the dipole magnets and field-free regions. The saturated value of the average EC density shows a clear threshold in N{sub b} beyond which the beam will be approximately neutralized on average. For the case of the LHC we limit our discussion to arc dipoles at collision energy, and bunch spacings t{sub b} = 25 ns or t{sub b} = 75 ns. The main variables exercised in this study are N{sub b} and the peak value of the secondary emission yield (SEY) {delta}{sub max}. For t{sub b} = 25 ns we conclude that the EC power deposition is comfortably below the available cooling capacity of the cryogenic system if {delta}{sub max} is below {approx} 1.2 at nominal N{sub b}. For t{sub b} = 75 ns, the EC power deposition is insignificant. As a byproduct of this exercise, we reach a detailed understanding of the significant role played by the backscattered secondary electrons. This article summarizes the results, an slightly extends the discussions, presented in Refs. 1 and 2.

  8. Synthesis and PET studies of [11C-cyano]letrozole (Femara), an aromatase inhibitor drug

    SciTech Connect

    kil K. E.; Biegon A.; Kil, K.-E.; Biegon, A.; Ding, Y.-S.; Fischer, A.; Ferrieri, R.A.; Kim, S.-W.; Pareto, D.; Schueller, M.J.; Fowler, J.S.

    2008-11-10

    Aromatase, a member of the cytochrome P450 family, converts androgens such as androstenedione and testosterone to estrone and estradiol respectively. Letrozole (1-[bis-(4-cyanophenyl)methyl]-1H-1,2,4-triazole, Femara{reg_sign}) is a high affinity aromatase inhibitor (K{sub i}=11.5 nM) which has FDA approval for breast cancer treatment. Here we report the synthesis of carbon-11 labeled letrozole and its assessment as a radiotracer for brain aromatase in the baboon. Letrozole and its precursor (4-[(4-bromophenyl)-1H-1,2,4-triazol-1-ylmethyl]benzonitrile, 3) were prepared in two-step syntheses from 4-cyanobenzyl bromide and 4-bromobenzyl bromide, respectively. The [{sup 11}C]cyano group was introduced via the tetrakis(triphenylphosphine)palladium(0) catalyzed coupling of [{sup 11}C]cyanide with the bromo-precursor (3). PET studies in the baboon brain were carried out to assess regional distribution and kinetics, reproducibility of repeated measures and saturability. The free fraction of letrozole in the plasma, log D, and the [{sup 11}C-cyano]letrozole fraction in the arterial plasma were also measured. [{sup 11}C-cyano]Letrozole was synthesized in 60 min with a radiochemical yield of 79-80%, with a radiochemical purity greater than 98% and a specific activity of 4.16 {+-} 2.21 Ci/{micro}mol at the end of bombardment (n=4). PET studies in the baboon revealed initial rapid and high uptake and initial rapid clearance followed by slow clearance of carbon-11 from the brain with no difference between brain regions. The brain kinetics was not affected by co-injection of unlabeled letrozole (0.1 mg/kg). The free fraction of letrozole in plasma was 48.9% and log D was 1.84. [{sup 11}C-cyano]Letrozole is readily synthesized via a palladium catalyzed coupling reaction with [{sup 11}C]cyanide. Although it is unsuitable as a PET radiotracer for brain aromatase as revealed by the absence of regional specificity and saturability in brain regions, such as amygdala, which are known

  9. Imaging Spectrum and Pitfalls of 11C-Methionine Positron Emission Tomography in a Series of Patients with Intracranial Lesions

    PubMed Central

    Matsuda, Hiroshi; Kubota, Kazoo

    2016-01-01

    11C-methionine (Met) positron emission tomography (PET) is one of the most commonly used PET tracers for evaluating brain tumors. However, few reports have described tips and pitfalls of 11C-Met PET for general practitioners. Physiological 11C-Met uptake, anatomical variations, vascular disorders, non-tumorous lesions such as inflammation or dysplasia, benign brain tumors and patient condition during 11C-Met PET examination can potentially affect the image interpretation and cause false positives and negatives. These pitfalls in the interpretation of 11C-Met PET images are important for not only nuclear medicine physicians but also general radiologists. Familiarity with the spectrum and pitfalls of 11C-Met images could help prevent unfavorable clinical results caused by misdiagnoses. PMID:27134530

  10. Imaging Spectrum and Pitfalls of (11)C-Methionine Positron Emission Tomography in a Series of Patients with Intracranial Lesions.

    PubMed

    Ito, Kimiteru; Matsuda, Hiroshi; Kubota, Kazoo

    2016-01-01

    (11)C-methionine (Met) positron emission tomography (PET) is one of the most commonly used PET tracers for evaluating brain tumors. However, few reports have described tips and pitfalls of (11)C-Met PET for general practitioners. Physiological (11)C-Met uptake, anatomical variations, vascular disorders, non-tumorous lesions such as inflammation or dysplasia, benign brain tumors and patient condition during (11)C-Met PET examination can potentially affect the image interpretation and cause false positives and negatives. These pitfalls in the interpretation of (11)C-Met PET images are important for not only nuclear medicine physicians but also general radiologists. Familiarity with the spectrum and pitfalls of (11)C-Met images could help prevent unfavorable clinical results caused by misdiagnoses. PMID:27134530

  11. Preliminary Ionization Efficiencies of {sup 11}C and {sup 14}O with the LBNL ECR Ion Sources

    SciTech Connect

    Xie, Z.Q.; Cerny, J.; Guo, F.Q.; Joosten, R.; Larimer, R.M.; Lyneis, C.M.; McMahan, P.; Norman, E.B.; O'Neil, J.P.; Powell, J.; Rowe, M.W.; VanBrocklin, H.F.; Wutte, D.; Xu, X.J.; Haustein, P.

    1998-10-05

    High charge states, up to fully stripped {sup 11}C and {sup 14}O ion, beams have been produced with the electron cyclotron resonance ion sources (LBNL, ECR and AECR-U) at Lawrence Berkeley National Laboratory. The radioactive atoms of {sup 11}C and {sup 14}O were collected in batch mode with an LN{sub 2} trap and then bled into the ECR ion sources. Ionization efficiency as high as 11% for {sup 11}C{sup 4+} was achieved.

  12. Spectroscopic Classification of Nova M31N 2015-11c

    NASA Astrophysics Data System (ADS)

    Williams, S. C.; Darnley, M. J.

    2015-12-01

    We obtained a spectrum of the M31 nova candidate M31N 2015-11c (PNV J00433852+4128026; ATel #8327) with the SPRAT spectrograph on the 2m Liverpool Telescope (Steele et al. 2004) on 2015 December 3.9 UT. The spectrum shows strong Balmer emission, with numerous Fe II lines also detected in emission (including the 42, 48, 49 and 74 multiplets), along with Na I (D) and [O I] (6300 and 6364 & Aring;).

  13. Production of L-(1-/sup 11/C)valine by HPLC resolution

    SciTech Connect

    Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Callahan, A.P.

    1982-01-01

    Based on a recently developed analytical technique, preparative high-performance liquid chromatographic (HPLC) resolution of DL-(1-/sup 11/C)valine has been achieved. A conventional reverse-phase HPLC column and a chiral mobile phase (aqueous solution of L-proline, cupric acetate, and sodium acetate) were used. The copper can be removed from the L-valine fraction by precipitation as the sulfide, and final purification by cation-exchange chromatography yields L-(1-/sup 11/C)valine in a form that is acceptable for clinical positron tomographic studies. This purification method does not remove the L-proline introduced in the resolution process, but added L-proline did not affect the tissue distribution of L-(1-/sup 14/C)valine in rats. We have produced up to 60 mCi of L-(1-/sup 11/C)valine in an overall synthesis and resolution time of 50 min. This procedure should be adaptable to the rapid resolution of other C-/sup 11/-labeled amino acid racemates.

  14. Production of L-(1-/sup 11/C)valine by HPLC resolution

    SciTech Connect

    Washburn, L.C.; Sun, T.T.; Byrd, B.L.; Callahan, A.P.

    1982-01-01

    Based on a recently developed analytical technique, preparative high-performance liquid chromatographic (HPLC) resolution of DL-(1-/sup 11/C)valine has been achieved. A conventional reverse-phase HPLC column and a chiral mobile phase (aqueous solution of L-proline, cupric acetate, and sodium acetate) were used. The copper can be removed from the L-valine fraction by precipitation as the sulfide, and final purification by cation-exchange chromatography yields L-(1-/sup 11/C)valine in a form that is acceptable for clinical positron tomographic studies. This purification method does not remove the L-proline introduced in the resolution process, but added L-proline did not affect the tissue distribution of L-(1-/sup 14/C)valine in rats. We have produced up to 60 mCi of L-(1-/sup 11/C)valine in an overall synthesis and resolution time of 50 min. This procedure should be adapable to the rapid resolution of other C-11-labeled amino acid racemates.

  15. Varenicline-Induced Elevation of Dopamine in Smokers: A Preliminary [(11)C]-(+)-PHNO PET Study.

    PubMed

    Di Ciano, Patricia; Guranda, Mihail; Lagzdins, Dina; Tyndale, Rachel F; Gamaleddin, Islam; Selby, Peter; Boileau, Isabelle; Le Foll, Bernard

    2016-05-01

    Varenicline, a nicotinic partial agonist, is the most effective treatment for tobacco use disorder. However, its mechanism of action is still unclear and may involve stimulating dopaminergic transmission. Here we used PET imaging with [(11)C]-(+)-PHNO to explore for the first time the impact of varenicline on dopamine transmission in the D2-rich striatum and D3-rich extra-striatal regions and its relationship with craving, withdrawal and smoking. Eleven treatment-seeking smokers underwent two PET scans with [(11)C]-(+)-PHNO, each following 12-h overnight smoking abstinence both prior to receiving varenicline and following 10-11 days of varenicline treatment (ie, at steady-state drug levels). Subjective measures of craving and urges to smoke were also assessed on the days of the PET scans. Varenicline treatment significantly reduced [(11)C]-(+)-PHNO binding in the dorsal caudate (p=0.008) and reduced some craving measures. These findings provide the first evidence that varenicline is able to increase DA levels in the human brain, a factor that may contribute to its therapeutic efficacy. PMID:26442600

  16. Efficiency Calibration for Measuring the 12C(n, 2n)11C Cross Section

    NASA Astrophysics Data System (ADS)

    Eckert, Thomas; Gula, August; Vincett, Laurel; Yuly, Mark; Padalino, Stephen; Russ, Megan; Bienstock, Mollie; Simone, Angela; Ellison, Drew; Desmitt, Holly; Sangster, Craig; Regan, Sean; Fitzgerald, Ryan

    2015-11-01

    One possible inertial confinement fusion diagnostic involves tertiary neutron activation via the 12C(n, 2n)11C reaction. A recent experiment to measure this reaction cross-section involved coincidence counting the annihilation gamma rays produced by the positron decay of 11C. This requires an accurate value for the full-peak coincidence efficiency of the NaI detector system. The GEANT 4 toolkit was used to develop a Monte Carlo simulation of the detector system which can be used to calculate the required efficiencies. For validation, simulation predictions have been compared with the results of two experiments. In the first, full-peak coincidence positron annihilation efficiencies were measured for 22Na decay positrons that annihilate in a small plastic scintillator. In the second, a NIST-calibrated 68Ge source was used. A comparison of calculated with measured efficiencies, as well as 12C(n, 2n)11C cross sections are presented. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.

  17. Novel synthesis of [11C]GVG (Vigabatgrin) for pharmacokinetic studies of addiction treatment

    SciTech Connect

    Ding, Y.S.; Studenov, A.R.; Zhang, Z.; Gerasimov, M.; Schiffer, W.; Dewey, S.L.; Telang, F.

    2001-06-10

    We report here a novel synthetic route to prepare the precursor and to efficiently label GVG with C-11. 5-Bromo-3-(carbobenzyloxy)amino-1-pentene was synthesized in five steps from homoserine lactone. This was used in a two step radiosynthesis, displacement with [{sup 11}C]cyanide followed by acid hydrolysis to afford [{sup 11}C]GVG with high radiochemical yields (> 35%, not optimized) and high specific activity (2-5 Ci/{micro}mol). The [{sup 11}C]cyanide trapping was achieved at {minus}5 C with a mixture of Kryptofix and K{sub 2}CO{sub 3} without using conventional aqueous trapping procedure [7]. At this temperature, the excess NH{sub 3} from the target that may interfere with the synthesis would not be trapped [8]. This procedure would be advantageous to any moisture sensitive radiosynthetic steps, as it was the case for our displacement reaction. When conventional aqueous trapping procedure was used, any trace amount of water left, even after prolonged heating, resulted in either no reaction or extremely low yields for the displacement reaction. The entire synthetic procedure should be extendible to the labeling of the pharmacologically active S- form of GVG when using S-homoserine lactone.

  18. Analysis of a Measurement of 12C(n,2n)11C Cross Sections

    NASA Astrophysics Data System (ADS)

    Hartshaw, Garrett; Love, Ian; Yuly, Mark; Padalino, Stephen; Russ, Megan; Bienstock, Mollie; Simone, Angela; Ellison, Drew; Desmitt, Holly; Massey, Thomas; Sangster, Craig

    2013-10-01

    In inertial confinement fusion (ICF), nuclear fusion reactions are initiated by bombarding a small fuel pellet with high power lasers. One ICF diagnostic tool involves placing graphite discs within the reaction chamber to determine the number of high-energy neutrons. This diagnostic requires accurate 12C(n, 2n)11C cross sections, which have not been previously well measured. An experiment to measure this cross section was conducted at Ohio University, in which DT neutrons irradiated polyethylene and graphite targets. The neutron flux was determined by counting recoil protons from the polyethylene in a silicon dE-E detector telescope. Preliminary cross sections were calculated using the incident neutron flux and the number of 11C nuclei in the graphite and polyethylene targets determined by counting, in a separate counting station, the gamma rays resulting from the positron decay of 11C. This poster will present the data analysis techniques used to determine these cross sections and the MCNPX simulation used to compute the corrections needed to account for the detector and target geometry. Funded in part by a LLE contract through the DOE.

  19. Reduced blood BDCA-2+ (lymphoid) and CD11c+ (myeloid) dendritic cells in systemic lupus erythematosus

    PubMed Central

    Migita, K; Miyashita, T; Maeda, Y; Kimura, H; Nakamura, M; Yatsuhashi, H; Ishibashi, H; Eguchi, K

    2005-01-01

    Type 1 IFN is thought to be implicated in the autoimmune process of SLE. Plasmacytoid dendric cells (DC), which are natural IFN-α producing cells, play a pivotal epipathogenic role in SLE. The present study was undertaken to investigate the phenotypic characteristics of peripheral blood DC in SLE patients in comparison with those of healthy controls. Samples from 20 SLE patients and 18 healthy controls were studied. Three-colour flow cytometry was performed to identify myeloid DC, as CD11c+ lineage marker−, and HLA-DR+ cells and plasmacytoid DC, as BDCA-2+ linage marker−, and HLA-DR+ cells. We used the whole blood ‘lyse/no-wash’ procedure, which allows precise counting of peripheral blood DC. BDCA-2+ plasmacytoid DC and CD11c+ myeloid DC were reduced in SLE patients compared with controls. Similarly, BDCA-3+ DC were reduced in SLE patients. These results indicated that SLE patients had a reduced number of both BDCA-2+ plasmacytoid DC and CD11c+ myeloid DC. These alternations of the DC subset may drive the autoimmune response in SLE. PMID:16178860

  20. Artifacts in time-resolved NUS: A case study of NOE build-up curves from 2D NOESY

    NASA Astrophysics Data System (ADS)

    Dass, Rupashree; Kasprzak, Paweł; Koźmiński, Wiktor; Kazimierczuk, Krzysztof

    2016-04-01

    Multidimensional NMR spectroscopy requires time-consuming sampling of indirect dimensions and so is usually used to study stable samples. However, dynamically changing compounds or their mixtures commonly occur in problems of natural science. Monitoring them requires the use multidimensional NMR in a time-resolved manner - in other words, a series of quick spectra must be acquired at different points in time. Among the many solutions that have been proposed to achieve this goal, time-resolved non-uniform sampling (TR-NUS) is one of the simplest. In a TR-NUS experiment, the signal is sampled using a shuffled random schedule and then divided into overlapping subsets. These subsets are then processed using one of the NUS reconstruction methods, for example compressed sensing (CS). The resulting stack of spectra forms a temporal "pseudo-dimension" that shows the changes caused by the process occurring in the sample. CS enables the use of small subsets of data, which minimizes the averaging of the effects studied. Yet, even within these limited timeframes, the sample undergoes certain changes. In this paper we discuss the effect of varying signal amplitude in a TR-NUS experiment. Our theoretical calculations show that the variations within the subsets lead to t1 -noise, which is dependent on the rate of change of the signal amplitude. We verify these predictions experimentally. As a model case we choose a novel 2D TR-NOESY experiment in which mixing time is varied in parallel with shuffled NUS in the indirect dimension. The experiment, performed on a sample of strychnine, provides a near-continuous NOE build-up curve, whose shape closely reflects the t1 -noise level. 2D TR-NOESY reduces the measurement time compared to the conventional approach and makes it possible to verify the theoretical predictions about signal variations during TR-NUS.

  1. Artifacts in time-resolved NUS: A case study of NOE build-up curves from 2D NOESY.

    PubMed

    Dass, Rupashree; Kasprzak, Paweł; Koźmiński, Wiktor; Kazimierczuk, Krzysztof

    2016-04-01

    Multidimensional NMR spectroscopy requires time-consuming sampling of indirect dimensions and so is usually used to study stable samples. However, dynamically changing compounds or their mixtures commonly occur in problems of natural science. Monitoring them requires the use multidimensional NMR in a time-resolved manner - in other words, a series of quick spectra must be acquired at different points in time. Among the many solutions that have been proposed to achieve this goal, time-resolved non-uniform sampling (TR-NUS) is one of the simplest. In a TR-NUS experiment, the signal is sampled using a shuffled random schedule and then divided into overlapping subsets. These subsets are then processed using one of the NUS reconstruction methods, for example compressed sensing (CS). The resulting stack of spectra forms a temporal "pseudo-dimension" that shows the changes caused by the process occurring in the sample. CS enables the use of small subsets of data, which minimizes the averaging of the effects studied. Yet, even within these limited timeframes, the sample undergoes certain changes. In this paper we discuss the effect of varying signal amplitude in a TR-NUS experiment. Our theoretical calculations show that the variations within the subsets lead to t1-noise, which is dependent on the rate of change of the signal amplitude. We verify these predictions experimentally. As a model case we choose a novel 2D TR-NOESY experiment in which mixing time is varied in parallel with shuffled NUS in the indirect dimension. The experiment, performed on a sample of strychnine, provides a near-continuous NOE build-up curve, whose shape closely reflects the t1-noise level. 2D TR-NOESY reduces the measurement time compared to the conventional approach and makes it possible to verify the theoretical predictions about signal variations during TR-NUS. PMID:26896866

  2. Kerogen to oil conversion in source rocks. Pore-pressure build-up and effects on seismic velocities

    NASA Astrophysics Data System (ADS)

    Pinna, Giorgia; Carcione, José M.; Poletto, Flavio

    2011-08-01

    The aim of this work is to obtain a model for source rocks relating to kerogen-oil conversion and pore pressure to seismic velocity and anisotropy. The source rock is described by a porous transversely isotropic medium composed of illite/smectite and organic matter. The rock has a very low permeability and pore-pressure build-up occurs. We consider a basin-evolution model with constant sedimentation rate and geothermal gradient. Kerogen-oil conversion starts at a given depth in a volume whose permeability is sufficiently low so that the increase in pressure due to oil generation greatly exceeds the dissipation of pressure by flow. Assuming a first-order kinetic reaction, with a reaction rate satisfying the Arrhenius equation, the kerogen-oil conversion fraction is calculated. Pore-pressure changes affect the dry-rock stiffnesses, which have an influence on seismic velocities. The properties of the kerogen-oil mixture are obtained with the Kuster and Toksöz model, assuming that oil is the inclusion in a kerogen matrix. We use Gassmann's equations generalized to the anisotropic case to obtain the seismic velocities of the source rock as a function of depth, pressure and oil saturation. The procedure is to obtain the dry-rock stiffnesses by assuming a Poisson medium for the mineral material constrained by the physical stability conditions at the calibration confining pressures. The example considers a sample of the North-Sea Kimmeridge shale. At a given depth, the conversion increases with increasing geothermal gradient and decreasing sedimentation rate, and the porosity increases with depth due to the conversion. As expected, the horizontal velocities are greater than the vertical velocities and the degree of anisotropy increases with depth. The analysis reveals that the vertical P-wave velocity is the main indicator of overpressure.

  3. Light parameters influence cell viability in antifungal photodynamic therapy in a fluence and rate fluence-dependent manner

    NASA Astrophysics Data System (ADS)

    Prates, Renato A.; da Silva, Eriques G.; Yamada, Aécio M.; Suzuki, Luis C.; Paula, Claudete R.; Ribeiro, Martha S.

    2009-05-01

    The aim of this study was to investigate the influence of light parameters on yeast cells. It has been proposed for many years that photodynamic therapy (PDT) can inactivate microbial cells. A number of photosensitizer and light sources were reported in different light parameters and in a range of dye concentrations. However, much more knowledge concerning the importance of fluence, fluence rate and exposure time are required for a better understanding of the photodynamic efficiency. Suspensions (106 CFU/mL) of Candida albicans, Candida krusei, and Cryptococcus neoformans var. grubii were used. Two fluence rates, 100 and 300 mW/cm2 were compared at 3, 6, and 9 min of irradiation, resulting fluences from 18 to 162 J/cm2. The light source was a laser emitting at λ = 660 nm with output power adjusted at 30 and 90 mW. As photosensitizer, one hundred-μM methylene blue was used. Temperature was monitored to verify possible heat effect and reactive oxygen species (ROS) formation was evaluated. The same fluence in different fluence rates showed dissimilar levels of inactivation on yeast cells as well as in ROS formation. In addition, the increase of the fluence rate showed an improvement on cell photoinactivation. PDT was efficient against yeast cells (6 log reduction), and no significant temperature increase was observed. Fluence per se should not be used as an isolate parameter to compare photoinactivation effects on yeast cells. The higher fluence rate was more effective than the lower one. Furthermore, an adequate duration of light exposure cannot be discarded.

  4. HIGH FLUENCE NEUTRON SOURCE FOR NONDESTRUCTIVE CHARACTERIZATION OF NUCLEAR WASTE

    EPA Science Inventory

    We propose to research the basic plasma physics necessary to develop a high fluence neutron source based on the inertial electrostatically confined (IEC) plasma. An intense neutron source directly addresses the capability to characterize nuclear materials under difficult measurem...

  5. System and Method for Determining Fluence of a Substance

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    2016-01-01

    A system and method for measuring a fluence of gas are disclosed. The system has a first light detector capable of outputting an electrical signal based on an amount of light received. A barrier is positionable adjacent the first light detector and is susceptible to a change in dimension from the fluence of the gas. The barrier permits a portion of light from being received by the first light detector. The change in the dimension of the barrier changes the electrical signal output from the first light detector. A second light detector is positionable to receive light representative of the first light detector without the barrier. The system and method have broad application to detect fluence of gas that may cause erosion chemical reaction causing erosive deterioration. One application is in low orbit Earth for detecting the fluence of atomic oxygen.

  6. Anisotropy of the neutron fluence from a plasma focus.

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Shomo, L. P.; Kim, K. H.

    1972-01-01

    The fluence of neutrons from a plasma focus was measured by gamma spectrometry of an activated silver target. This method results in a significant increase in accuracy over the beta-counting method. Multiple detectors were used in order to measure the anisotropy of the fluence of neutrons. The fluence was found to be concentrated in a cone with a half-angle of 30 deg about the axis, and to drop off rapidly outside of this cone; the anisotropy was found to depend upon the total yield of neutrons. This dependence was strongest on the axis. Neither the axial concentration of the fluence of neutrons nor its dependence on the total yield of neutrons is explained by any of the currently proposed models. Some other explanations, including the possibility of an axially distributed source, are considered.

  7. Imaging Evaluation of 5HT2C Agonists, [11C]WAY-163909 and [11C]Vabicaserin, Formed by Pictet–Spengler Cyclization

    PubMed Central

    2015-01-01

    The serotonin subtype 2C (5HT2C) receptor is an emerging and promising drug target to treat several disorders of the human central nervous system. In this current report, two potent and selective 5HT2C full agonists, WAY-163909 (2) and vabicaserin (3), were radiolabeled with carbon-11 via Pictet–Spengler cyclization with [11C]formaldehyde and used in positron emission tomography (PET) imaging. Reaction conditions were optimized to exclude the major source of isotope dilution caused by the previously unknown breakdown of N,N-dimethylformamide (DMF) to formaldehyde at high temperature under mildly acid conditions. In vivo PET imaging was utilized to evaluate the pharmacokinetics and distribution of the carbon-11 labeled 5HT2C agonists. Both radiolabeled molecules exhibit high blood–brain barrier (BBB) penetration and nonspecific binding, which was unaltered by preadministration of the unlabeled agonist. Our work demonstrates that Pictet–Spengler cyclization can be used to label drugs with carbon-11 to study their pharmacokinetics and for evaluation as PET radiotracers. PMID:24491146

  8. A simplified analytical method to estimate the bismuth build-up and the polonium activity in LiPb-bearing blankets of a fusion reactor

    SciTech Connect

    Zimin, S.

    1994-09-01

    Although neutron-induced activation in a fusion reactor is a nonlinear problem whose solution requires the use of both neutron transport and activation codes, a simplified analytical approach to bismuth and polonium build-up in lead is proposed to estimate the polonium inventory and the related biological hazards of LiPb-bearing blankets. All neutronic reactions of polonium build-up in lead and in its bismuth impurities are surveyed and discussed. The contribution of the different possible chains to the build-up of polonium is evaluated. A set of differential equations for the densities of {sup 209}Bi and {sup 210}Po isotopes in the lead is worked into simplified, easy-to-use expressions. These analytical formulas obtained for the densities can be used for the estimation of both the bismuth and the polonium densities after any reactor operation time and allow identification of the build-up mechanisms of those isotopes. A simplified formula for polonium inventory estimations at any blanket zone is proposed as well. The polonium inventory evaluation takes into account the initial conditions (primarily bismuth impurity in the lead) and the reactor operation conditions, such as the average availability of a fusion reactor and the blanket operation scenario. 44 refs., 11 figs., 5 tabs.

  9. Effects of salinity build-up on biomass characteristics and trace organic chemical removal: implications on the development of high retention membrane bioreactors.

    PubMed

    Luo, Wenhai; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2015-02-01

    This study investigated the impact of salinity build-up on the performance of membrane bioreactor (MBR), specifically in terms of the removal and fate of trace organic chemicals (TrOCs), nutrient removal, and biomass characteristics. Stepwise increase of the influent salinity, simulating salinity build-up in high retention MBRs, adversely affected the metabolic activity in the bioreactor, thereby reducing organic and nutrient removal. The removal of hydrophilic TrOCs by MBR decreased due to salinity build-up. By contrast, with the exception of 17α-ethynylestradiol, the removal of all hydrophobic TrOCs was not affected at high salinity. Moreover, salinity build-up had negligible impact on the residual accumulation of TrOCs in the sludge phase except for a few hydrophilic compounds. Additionally, the response of the biomass to salinity stress also dramatically enhanced the release of both soluble microbial products (SMP) and extracellular polymeric substances (EPS), leading to severe membrane fouling. PMID:25496948

  10. Effects of fluence rate on cytoxicity during photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Sitnik, Theresa M.; Henderson, Barbara W.

    1997-05-01

    Production of 1O2 during PDT may be limited as a consequence of tissue oxygen depletion by the photodynamic process. This may in turn limit cytotoxicity during PDT. One possible way of controlling oxygen consumption during treatment is through modification of fluence rate. We have studied the impact of fluence rate on tumor oxygenation and direct PDT cytotoxicity using the RIF murine tumor and the photosensitizer Photofrin. Both fluence rates caused an acute decrease in tumor pO2 to severely hypoxic levels. With 150 mW/cm2 light median pO2 remained low during prolonged exposure, while with 30 mW/cm2 light median pO2 values recovered to above control levels. When tumors treated with 135 J/cm2 at each fluence rate were tested for cell survival in a clonogenic assay, 30 mW/cm2 significantly decreased both cell clonogenicity and plating efficiency compared to light-only controls. Slight but insignificant decreases were found with 150 mW/cm2. During in vitro PDT the fluence rate of light delivery had no effect on cell survival. In summary, we have found that low fluence rate improves tumor oxygenation and direct cell effects during PDT.

  11. The optimization of intensity modulated radiotherapy in cases where the planning target volume extends into the build-up region.

    PubMed

    Nguyen, T B; Hoole, A C F; Burnet, N G; Thomas, S J

    2009-04-21

    A common clinical problem in IMRT, especially when treating head and neck cases, is that the clinical target volume (CTV) stops short of the skin surface, whilst the margin for geometric uncertainties may take the planning target volume (PTV) to the skin surface or beyond. In these cases, optimization leads to over-dosing of the skin, unless the planner resorts to procedural tricks to avoid this, such as the use of pretend bolus or reduction of the PTV followed by adding 'flash' after optimization. This paper describes a method of avoiding the need for these tricks by using a multiple-isocentre CTV-based objective function. This enables plans to be produced that will give good coverage of the CTV for all the geometrical uncertainties that would have been covered by the PTV without causing the problem of over-dosing the skin. Eight isocentre shifts, equally distributed on the surface of a sphere with a radius equal to the CTV-PTV margin, are shown to be adequate for the optimization process. The resulting fluence maps are much simpler than those resulting from PTV optimization and will therefore be simpler to deliver. The method also permits better sparing of organs at risk such as the spinal cord. PMID:19336846

  12. The CD11c antigen couples concanavalin A binding to generation of superoxide anion in human phagocytes.

    PubMed Central

    Lacal, P M; Balsinde, J; Cabañas, C; Bernabeu, C; Sánchez-Madrid, F; Mollinedo, F

    1990-01-01

    We have found that an anti-CD11c monoclonal antibody (MAb) inhibits the respiratory burst induced in phorbol 12-myristate 13-acetate (PMA)-differentiated U937 cells as well as in human peripheral blood monocytes and neutrophils upon cell stimulation with concanavalin A. The MAb had no effect, however, when the added stimulus was fMet-Leu-Phe or PMA. Flow cytometry analyses indicated that concanavalin A was able to interact with CD11c. The anti-CD11c MAb inhibited significantly concanavalin A binding to differentiated U937 cells, and concanavalin A blocked binding of anti-CD11c MAb to the cells. Binding of labelled concanavalin A to membrane proteins which were separated by PAGE and transferred to nitrocellulose paper indicated that proteins with apparent molecular masses similar to those of CD11c (150 kDa) and CD18 (95 kDa) molecules were the main concanavalin A-binding proteins in differentiated U937 cells as well as in mature neutrophils. Similar experiments carried out in the presence of the anti-CD11c MAb showed a specific and significant inhibition of concanavalin A binding to the CD11c molecule. These results indicate that concanavalin A binds to the CD11c molecule and this binding is responsible for the concanavalin A-induced respiratory burst in PMA-differentiated U937 cells as well as in human mature monocytes and neutrophils. Images Fig. 2. Fig. 3. PMID:1973035

  13. Delayed build-up of Arctic ice sheets during 400, 000-year minima in insolation variability confirmed by Chinese loess

    NASA Astrophysics Data System (ADS)

    Hao, Q.; Wang, L.; Oldfield, F.; Peng, S.; Qin, L.; Song, Y.; Xu, B.; Qiao, Y.; Bloemendal, J.; Guo, Z.

    2013-12-01

    The growth and decay of the Northern Hemisphere ice volume led to alternations of glacial and interglacial climate and major changes in sea level during the Quaternary period. Unfortunately, long-term continuous records of ice-sheet variability in the Northern during the Quaternary period Hemisphere only are scarce because benthic δ18O records represent an integrated signal of changes in ice volume in both polar regions. Direct sedimentary records of Northern Hemisphere polar ice sheets exist only for the late Quaternary and longer term records are scarce. However, variations in Northern Hemisphere ice sheets influence the Siberian High (an atmospheric pressure system), so variations in the East Asian winter monsoon (EAWM)--as recorded in the aeolian dust deposits on the Chinese Loess Plateau--can serve as a useful proxy of Arctic climate variability. Here we present an EAWM proxy record using grain-size variations in two parallel loess sections over the past 900 kyr to address the timing of build-up of Northern hemisphere ice sheets around 413 kyr mimina in eccentricity and precessional variability. These periods are regarded as the astronomical analogues of the present interglacial. The results show that during periods of low eccentricity and precessional variability around 400 kyr and 800 kyr ago, the grain-size-inferred intensity of the EAWM remains weak for up to 20 kyr after the end of the interglacial episodes MIS 11, MIS 19 and MIS 21. In contrast, there is a rapid increase in the EAWM after the end of most other interglacials. We conclude that, for these interglacials at 400 kyr intervals, the weak EAWM winds maintain a non-glacial climate at high northern latitudes for much longer than expected from the conventional loess and marine oxygen isotope records. During these times, the less severe summer insolation minima at 65° N (modulated by 413-kyr eccentricity cycles) would have suppressed ice and snow accumulation, leading to a weak Siberian High and

  14. A comprehensive interpretation of the NEEM basal ice build-up using a multi-parametric approach

    NASA Astrophysics Data System (ADS)

    Goossens, Thomas; Sapart, Célia J.; Dahl-Jensen, Dorthe; Popp, Trevor; El Amri, Saïda; Tison, Jean-Louis

    2016-03-01

    stratified debris-rich layers and the ice containing dispersed debris layers respectively express an "open" or "closed" system melting/refreezing signature, somewhat blurred by mixing processes in the upper part of the sequence. Climatic reconstruction is therefore prohibited from these ice types. We propose a first interpretative framework for the build-up of the NEEM basal ice sequence, based on the origin of the various ice types.

  15. Study of Nuclear Reactions with 11C and 15O Radioactive Ion Beams

    SciTech Connect

    Lee, Dongwon

    2007-05-14

    Nuclear reaction study with radioactive ion beams is one of the most exciting research topics in modern nuclear physics. The development of radioactive ion beams has allowed nuclear scientists and engineers to explore many unknown exotic nuclei far from the valley of nuclear stability, and to further our understanding of the evolution of the universe. The recently developed radioactive ion beam facility at the Lawrence Berkeley National Laboratory's 88-inch cyclotron is denoted as BEARS and provides {sup 11}C, {sup 14}O and {sup 15}O radioactive ion beams of high quality. These moderate to high intensity, proton-rich radioactive ion beams have been used to explore the properties of unstable nuclei such as {sup 12}N and {sup 15}F. In this work, the proton capture reaction on {sup 11}C has been evaluated via the indirect d({sup 11}C, {sup 12}N)n transfer reaction using the inverse kinematics method coupled with the Asymptotic Normalization Coefficient (ANC) theoretical approach. The total effective {sup 12}N {yields} {sup 11}C+p ANC is found to be (C{sub eff}{sup 12{sub N}}){sup 2} = 1.83 {+-} 0.27 fm{sup -1}. With the high {sup 11}C beam intensity available, our experiment showed excellent agreement with theoretical predictions and previous experimental studies. This study also indirectly confirmed that the {sup 11}C(p,{gamma}) reaction is a key step in producing CNO nuclei in supermassive low-metallicity stars, bypassing the slow triple alpha process. The newly developed {sup 15}O radioactive ion beam at BEARS was used to study the poorly known level widths of {sup 16}F via the p({sup 15}O,{sup 15}O)p reaction. Among the nuclei in the A=16, T=1 isobaric triad, many states in {sup 16}N and {sup 16}O have been well established, but less has been reported on {sup 16}F. Four states of {sup 16}F below 1 MeV have been identified experimentally: 0{sup -}, 1{sup -}, 2{sup -}, and 3{sup -} (E{sub x} = 0.0, 0.19, 0.42, and 0.72 MeV, respectively). Our study utilized R

  16. Effect of vehicle on brain uptake of [11C]toluene.

    PubMed

    Gerasimov, Madina R; Logan, Jean; Ferrieri, Richard A; Muller, Ryan D; Alexoff, David; Dewey, Stephen L

    2002-07-01

    With the goal of investigating the pharmacokinetics of the abused solvent, toluene we have adapted the rapid coupling of methyl iodide with tributylphenylstannane mediated by palladium(0) complex to the synthesis of no-carrier-added [11C]toluene starting with 11CH(3)I. Two methods for purification and formulation of the tracer were developed. The first one yielded [11C]toluene dissolved in dimethylacetamide/saline solution, for the second one we adapted supercritical fluid technology where the tracer was purified using and conventional C(18) HPLC column and pure supercritical CO(2) fluid as a mobile phase operating at 2000 psi. Formulation of the tracer in cyclodextrin resulted in a significantly higher integrated uptake and distribution volume values. Additionally, we observed higher uptake and slower clearance of 11C-toluene in white matter, consistent with higher lipid content and neurotoxicological evidence indicating restricted and diffuse white matter changes in toluene abusers. This trend was observed when either DMA or cyclodextrin was used as a vehicle. It appears then, that the choice of a vehicle affected only the degree of bioavailability, but not the regional brain pharmacokinetics. Finally, we demonstrated the effect of a decreased percent difference between DV values for the studies performed on the same day, that is, test/retest variability was lower for all brain regions in beta-cyclodextrin experiments. Present results clearly demonstrate that the choice of a vehicle has a significant effect on tracer uptake and should be considered as a potential factor contributing to the pharmacokinetic measurements. PMID:12088732

  17. Measuring Cigarette Smoking-Induced Cortical Dopamine Release: A [11C]FLB-457 PET Study

    PubMed Central

    Wing, Victoria C; Payer, Doris E; Houle, Sylvain; George, Tony P; Boileau, Isabelle

    2015-01-01

    Striatal dopamine (DA) is thought to have a fundamental role in the reinforcing effects of tobacco smoking and nicotine. Microdialysis studies indicate that nicotine also increases DA in extrastriatal brain areas, but much less is known about its role in addiction. High-affinity D2/3 receptor radiotracers permit the measurement of cortical DA in humans using positron emission tomography (PET). [11C]FLB-457 PET scans were conducted in 10 nicotine-dependent daily smokers after overnight abstinence and reinstatement of smoking. Voxel-wise [11C]-FLB-457-binding potential (BPND) in the frontal lobe, insula, and limbic regions was estimated in the two conditions. Paired t-tests showed BPND values were reduced following smoking (an indirect index of DA release). The overall peak t was located in the cingulate gyrus, which was part of a larger medial cluster (BPND change −12.1±9.4%) and this survived false discovery rate correction for multiple comparisons. Clusters were also identified in the left anterior cingulate cortex/medial frontal gyrus, bilateral prefrontal cortex (PFC), bilateral amygdala, and the left insula. This is the first demonstration of tobacco smoking-induced cortical DA release in humans; it may be the result of both pharmacological (nicotine) and non-pharmacological factors (tobacco cues). Abstinence increased craving but had minimal cognitive effects, thus limiting correlation analyses. However, given that the cingulate cortex, PFC, insula, and amygdala are thought to have important roles in tobacco craving, cognition, and relapse, these associations warrant investigation in a larger sample. [11C]FLB-457 PET imaging may represent a useful tool to investigate individual differences in tobacco addiction severity and treatment response. PMID:25502631

  18. Amino acids labelled with 11C as indicator of the effect of dietary treatment of hyperammonaemia.

    PubMed

    Hardell, L I; Stålnacke, C G; Lundqvist, H; Malmborg, P; Långström, B

    1984-01-01

    Short-lived radioactive carbon, 11C, (T 1/2 = 20 min) was incorporated into an essential amino acid [11C-methyl] -L-methionine, to form a true biological amino acid tracer with external detectability. This was tested in a study of the physiological tracer dynamics in a hyperammonaemic patient before and after a change in the dietary treatment. The protein intake was unchanged between the two investigations but the energy intake was increased from 53 to 63 kcal/kg BW/day. The tracer radioactivity was given per os. In the second investigation a relative decrease of radioactivity in the low molecular weight fraction of blood plasma was seen. Also the external measurements indicated a higher hepatic retention of radioactivity in the second investigation but no increased excretion of tracer. This may reflect an increased ability of the liver to utilize the incoming methionine from the vena porta. The hyperammonaemia remained over the second investigation but seven months later the ammonia content in the blood was almost normalized and the patient had also gained 3 kg in weight. The correlation between changes in tracer dynamics and changes in therapeutical effect of the diet is not further verified in this experiment but the investigation indicates the value of further studies in this topic using 11C-labelled amino acids also including the use of the newly introduced positron tomographic technique. It may be possible to develop this type of nuclide technique further to achieve a clinically useful method of optimizing therapeutic regiments in this type of metabolic disease. PMID:6393522

  19. Evaluation of [(11)C]N-Methyl Lansoprazole as a Radiopharmaceutical for PET Imaging of Tau Neurofibrillary Tangles.

    PubMed

    Shao, Xia; Carpenter, Garrett M; Desmond, Timothy J; Sherman, Phillip; Quesada, Carole A; Fawaz, Maria; Brooks, Allen F; Kilbourn, Michael R; Albin, Roger L; Frey, Kirk A; Scott, Peter J H

    2012-11-01

    [(11)C]N-Methyl lansoprazole ([(11)C]NML, 3) was synthesized and evaluated as a radiopharmaceutical for quantifying tau neurofibrillary tangle (NFT) burden using positron emission tomography (PET) imaging. [(11)C]NML was synthesized from commercially available lansoprazole in 4.6% radiochemical yield (noncorrected RCY, based upon [(11)C]MeI), 99% radiochemical purity, and 16095 Ci/mmol specific activity (n = 5). Log P was determined to be 2.18. A lack of brain uptake in rodent microPET imaging revealed [(11)C]NML to be a substrate for the rodent permeability-glycoprotein 1 (PGP) transporter, but this could be overcome by pretreating with cyclosporin A to block the PGP. Contrastingly, [(11)C]NML was not found to be a substrate for the primate PGP, and microPET imaging in rhesus revealed [(11)C]NML uptake in the healthy primate brain of ∼1600 nCi/cc maximum at 3 min followed by rapid egress to 500 nCi/cc. Comparative autoradiography between wild-type rats and transgenic rats expressing human tau (hTau +/+) revealed 12% higher uptake of [(11)C]NML in the cortex of brains expressing human tau. Further autoradiography with tau positive brain samples from progressive supranuclear palsy (PSP) patients revealed colocalization of [(11)C]NML with tau NFTs identified using modified Bielschowsky staining. Finally, saturation binding experiments with heparin-induced tau confirmed K d and Bmax values of [(11)C]NML as 700 pM and 0.214 fmol/μg, respectively. PMID:24900410

  20. Nuclear reactions with 11C and 14O radioactive ion beams

    SciTech Connect

    Guo, Fanqing

    2004-12-09

    Radioactive ion beams (RIBs) have been shown to be a useful tool for studying proton-rich nuclides near and beyond the proton dripline and for evaluating nuclear models. To take full advantage of RIBs, Elastic Resonance Scattering in Inverse Kinematics with Thick Targets (ERSIKTT), has proven to be a reliable experimental tool for investigations of proton unbound nuclei. Following several years of effort, Berkeley Experiments with Accelerated Radioactive Species (BEARS), a RIBs capability, has been developed at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. The current BEARS provides two RIBs: a 11C beam of up to 2x108 pps intensity on target and an 14O beam of up to 3x104 pps intensity. While the development of the 11C beam has been relatively easy, a number of challenges had to be overcome to obtain the 14O beam. The excellent 11C beam has been used to investigate several reactions. The first was the 197Au(11C,xn)208-xnAt reaction, which was used to measure excitation functions for the 4n to 8n exit channels. The measured cross sections were generally predicted quite well using the fusion-evaporation code HIVAP. Possible errors in the branching ratios of ?? decays from At isotopes as well as the presence of incomplete fusion reactions probably contribute to specific overpredictions. 15F has been investigated by the p(14O,p)14O reaction with the ERSIKTT technology. Several 14O+p runs have been performed. Excellent energy calibration was obtained using resonances from the p(14N,p)14N reaction in inverse kinematics, and comparing the results to those obtained earlier with normal kinematics. The differences between 14N+p and 14O+p in the stopping power function have been evaluated for better energy calibration. After careful calibration, the energy levels of 15F were fitted with an R-matrix calculation. Spins and parities were assigned to the two observed resonances. This new measurement of the 15F ground state supports the disappearance of the Z = 8

  1. Synthesis of (11)C-Labeled Thiamine and Fursultiamine for in Vivo Molecular Imaging of Vitamin B1 and Its Prodrug Using Positron Emission Tomography.

    PubMed

    Doi, Hisashi; Mawatari, Aya; Kanazawa, Masakatsu; Nozaki, Satoshi; Nomura, Yukihiro; Kitayoshi, Takahito; Akimoto, Kouji; Suzuki, Masaaki; Ninomiya, Shinji; Watanabe, Yasuyoshi

    2015-06-19

    To enable in vivo analysis of the kinetics of vitamin B1 (thiamine) and its derivatives by positron emission tomography (PET), (11)C-labeled thiamine ([(11)C]-1) has been synthesized. This was carried out via a rapid, multistep synthesis consisting of Pd(0)-mediated C-[(11)C]methylation of a thiazole ring for 3 min and benzylation with 5-(bromomethyl)pyrimidine for 7 min. The [(11)C]-1 was also converted to (11)C-labeled fursultiamine ([(11)C]-2), a prodrug of vitamin B1, by disulfide formation with S-tetrahydrofurfurylthiosulfuric acid sodium salt. Characterization of [(11)C]-1 and [(11)C]-2 showed them to be suitable for use as PET probes for in vivo pharmacokinetic and medical studies. The total durations of the preparations of [(11)C]-1 and [(11)C]-2 were shorter than 60 and 70 min, respectively. The [(11)C]CH3I-based decay-corrected radiochemical yields of [(11)C]-1 and [(11)C]-2 were 9-16% and 4-10%, respectively. The radioactivities of the final injectable solutions of [(11)C]-1 and [(11)C]-2 were 400-700 and 100-250 MBq, respectively. The radiochemical purity of both [(11)C]-1 and [(11)C]-2 was 99%, and the chemical purities of [(11)C]-1 and [(11)C]-2 were 99% and 97-99%, respectively. In vivo PET imaging of normal rats was illustrated by the distribution of [(11)C]-1 and [(11)C]-2 following intravenous injection. PMID:25984933

  2. Cryogenic molecular separation system for radioactive {sup 11}C ion acceleration

    SciTech Connect

    Katagiri, K.; Noda, A.; Suzuki, K.; Nagatsu, K.; Nakao, M.; Hojo, S.; Wakui, T.; Noda, K.; Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ramzdorf, A. Yu.

    2015-12-15

    A {sup 11}C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive {sup 11}C ion beams. In the ISOL system, {sup 11}CH{sub 4} molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive {sup 12}CH{sub 4} gases, which can simulate the chemical characteristics of {sup 11}CH{sub 4} gases. We investigated the separation of CH{sub 4} molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH{sub 4}. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system.

  3. Practical Radiosynthesis and Preclinical Neuroimaging of [11C]isradipine, A Calcium Channel Antagonist

    PubMed Central

    Rotstein, Benjamin H.; Liang, Steven H.; Belov, Vasily V.; Livni, Eli; Levine, Dylan B.; Bonab, Ali A.; Papisov, Mikhail I.; Perlis, Roy H.; Vasdev, Neil

    2016-01-01

    In the interest of developing in vivo positron emission tomography (PET) probes for neuroimaging of calcium channels, we have prepared a carbon-11 isotopologue of a dihydropyridine Ca2+-channel antagonist, isradipine. Desmethyl isradipine (4-(benzo[c][1,2,5]oxadiazol-4-yl)-5-(isopropoxycarbonyl)-2,6-dimethyl-1,4-dihydropyridine -3-carboxylic acid) was reacted with [11C]CH3I in the presence of tetrabutylammonium hydroxide in DMF in an HPLC injector loop to produce the radiotracer in a good yield (6 ± 3% uncorrected radiochemical yield) and high specific activity (143 ± 90 GBq·μmol−1 at end-of-synthesis). PET imaging of normal rats revealed rapid brain uptake at baseline (0.37 ± 0.08 %ID/cc (percent of injected dose per cubic centimeter) at peak, 15–60 s), which was followed by fast washout. After pretreatment with isradipine (2 mg·kg−1, i.p.), whole brain radioactivity uptake was diminished by 25–40%. This preliminary study confirms that [11C]isradipine can be synthesized routinely for research studies and is brain penetrating. Further work on Ca2+-channel radiotracer development is planned. PMID:26016546

  4. Practical Radiosynthesis and Preclinical Neuroimaging of [11C]isradipine, a Calcium Channel Antagonist.

    PubMed

    Rotstein, Benjamin H; Liang, Steven H; Belov, Vasily V; Livni, Eli; Levine, Dylan B; Bonab, Ali A; Papisov, Mikhail I; Perlis, Roy H; Vasdev, Neil

    2015-01-01

    In the interest of developing in vivo positron emission tomography (PET) probes for neuroimaging of calcium channels, we have prepared a carbon-11 isotopologue of a dihydropyridine Ca2+-channel antagonist, isradipine. Desmethyl isradipine (4-(benzo[c][1,2,5]oxadiazol-4-yl)-5-(isopropoxycarbonyl)-2,6-dimethyl-1,4-dihydropyridine -3-carboxylic acid) was reacted with [11C]CH3I in the presence of tetrabutylammonium hydroxide in DMF in an HPLC injector loop to produce the radiotracer in a good yield (6 ± 3% uncorrected radiochemical yield) and high specific activity (143 ± 90 GBq·µmol-1 at end-of-synthesis). PET imaging of normal rats revealed rapid brain uptake at baseline (0.37 ± 0.08% ID/cc (percent of injected dose per cubic centimeter) at peak, 15-60 s), which was followed by fast washout. After pretreatment with isradipine (2 mg·kg-1, i.p.), whole brain radioactivity uptake was diminished by 25%-40%. This preliminary study confirms that [11C]isradipine can be synthesized routinely for research studies and is brain penetrating. Further work on Ca2+-channel radiotracer development is planned. PMID:26016546

  5. Supercritical CO2 fluid radiochromatography system used to purify [11C]toluene for PET.

    PubMed

    Muller, Ryan D; Ferrieri, Richard A; Gerasimov, Madina; Garza, Victor

    2002-04-01

    Abuse of inhalants in today's society has become such a widespread problem among today's adolescents that in many parts of the world their use exceeds that of many other illicit drugs or alcohol. Even so, little is known how such inhalants affect brain function to an extent that can lead to an abuse liability. While methodologies exist for radiolabeling certain inhalants of interest with short-lived positron emitting radioisotopes that would allow their investigation in human subjects using positron emission tomography (PET), the purification methodologies necessary to separate these volatile substances from the organic starting materials have not been developed. We've adapted supercritical fluid technology to this specific PET application by building a preparative-scale supercritical CO2 fluid radiochromatograph, and applied it to the purification of [11C]toluene. We've demonstrated that [11C]toluene can be separated from the starting materials using a conventional C18 HPLC column and pure supercritical CO2 fluid as the mobile phase operating at 2000 psi and 40 degrees C. We've also shown that the purified radiotracer can be quantitatively captured on Tenax GR, a solid support material, as it exits the supercritical fluid stream, thus allowing for later desorption into a 1.5% cyclodextrin solution that is suitable for human injection, or into a breathing tube for direct inhalation. PMID:11929706

  6. Elevated [11C]-D-Deprenyl Uptake in Chronic Whiplash Associated Disorder Suggests Persistent Musculoskeletal Inflammation

    PubMed Central

    Linnman, Clas; Appel, Lieuwe; Fredrikson, Mats; Gordh, Torsten; Söderlund, Anne; Långström, Bengt; Engler, Henry

    2011-01-01

    There are few diagnostic tools for chronic musculoskeletal pain as structural imaging methods seldom reveal pathological alterations. This is especially true for Whiplash Associated Disorder, for which physical signs of persistent injuries to the neck have yet to be established. Here, we sought to visualize inflammatory processes in the neck region by means Positron Emission Tomography using the tracer 11C-D-deprenyl, a potential marker for inflammation. Twenty-two patients with enduring pain after a rear impact car accident (Whiplash Associated Disorder grade II) and 14 healthy controls were investigated. Patients displayed significantly elevated tracer uptake in the neck, particularly in regions around the spineous process of the second cervical vertebra. This suggests that whiplash patients have signs of local persistent peripheral tissue inflammation, which may potentially serve as a diagnostic biomarker. The present investigation demonstrates that painful processes in the periphery can be objectively visualized and quantified with PET and that 11C-D-deprenyl is a promising tracer for these purposes. PMID:21541010

  7. Elevated [11C]-D-deprenyl uptake in chronic Whiplash Associated Disorder suggests persistent musculoskeletal inflammation.

    PubMed

    Linnman, Clas; Appel, Lieuwe; Fredrikson, Mats; Gordh, Torsten; Söderlund, Anne; Långström, Bengt; Engler, Henry

    2011-01-01

    There are few diagnostic tools for chronic musculoskeletal pain as structural imaging methods seldom reveal pathological alterations. This is especially true for Whiplash Associated Disorder, for which physical signs of persistent injuries to the neck have yet to be established. Here, we sought to visualize inflammatory processes in the neck region by means Positron Emission Tomography using the tracer (11)C-D-deprenyl, a potential marker for inflammation. Twenty-two patients with enduring pain after a rear impact car accident (Whiplash Associated Disorder grade II) and 14 healthy controls were investigated. Patients displayed significantly elevated tracer uptake in the neck, particularly in regions around the spineous process of the second cervical vertebra. This suggests that whiplash patients have signs of local persistent peripheral tissue inflammation, which may potentially serve as a diagnostic biomarker. The present investigation demonstrates that painful processes in the periphery can be objectively visualized and quantified with PET and that (11)C-D-deprenyl is a promising tracer for these purposes. PMID:21541010

  8. Kinetic Analysis of [11C]McN5652: A Serotonin Transporter Radioligand

    PubMed Central

    Szabo, Zsolt; Scheffel, Ursula; Mathews, William B.; Ravert, Hayden T.; Szabo, Katalina; Kraut, Michael; Palmon, Sally; Ricaurte, George A.; Dannals, Robert F.

    2007-01-01

    Summary The impulse response function of a radioligand is the most fundamental way to describe its pharmacokinetics and to assess its tissue uptake and retention pattern. This study investigates the impulse response function of [11C](+)McN5652, a radioligand used for positron emission tomography (PET) imaging of the serotonin transporter (SERT) in the brain. Dynamic PET studies were performed in eight healthy volunteers injected with [11C](+)McN5652 and subsequently with its pharmacologically inactive enantiomer [11C](−)McN5652. The impulse response function was calculated by deconvolution analysis of regional time-activity curves, and its peak value (fmax), its retention value at 75 minutes (fT), and its normalized retention (frel = fr/fmax) were obtained. Alternatively, compartmental models were applied to calculate the apparent total distribution volume (DVT) and its specific binding component (DVS). Both the noncompartmental (fT, frel) and the compartmental parameters (DV) were investigated with and without correction for nonspecific binding by simple subtraction of the corresponding value obtained with [11C](−)McN5652. The impulse response function obtained by deconvolution analysis demonstrated high tracer extraction followed by a slow decline in the form of a monoexponential function. Statistical analysis revealed that the best compartmental model in terms of analysis of variance F and condition number of the parameter variance-covariance matrix was the one that was based on a single tissue compartment with parameters k1and k2 and that also included the parameter of regional cerebral blood volume (BV). The parameter frel demonstrated low between-subject variance (coefficient of variation [CV] = 19%), a midbrain to cerebellum ratio of 1.85, and high correlation with the known density of SERT (r = 0.787 where r is the coefficient of linear correlation between the parameter and the known density of SERT). After correction for nonspecific binding, frel

  9. Dynamic study of supratentorial gliomas with L-methyl-/sup 11/C-methionine and positron emission tomography

    SciTech Connect

    Lilja, A.; Bergstroem, K.H.; Hartvig, P.; Spaennare, B.H.; Halldin, C.; Lundqvist, H.; Langstrom, B.

    1985-07-01

    The regional kinetics of intravenously injected L-methyl-/sup 11/C-methionine (/sup 11/C-L-methionine) in the brain was investigated by positron emission tomography (PET) in 14 patients with gliomas. In both tumor and unaffected brain the tracer uptake reached a nearly constant level in 5 min or less. The ratio between the uptake of /sup 11/C-L-methionine by high-grade tumors and the uptake by unaffected brain was 1.9-4.8. In two cases of low-grade astrocytoma the ratio was 0.8-1.0. High uptakes of /sup 11/C-L-methionine occurred in gliomas even in the absence of blood-brain barrier defects as observed by other methods. This indicates that besides active transport of amino acid, a larger extracellular space in tumor as compared with unaffected brain tissue may also contribute to the increased uptake of /sup 11/C-L-methionine--derived radioactivity. In some patients delineation of the tumors was improved by use of PET with /sup 11/C-L-methionine as compared with computed tomography, angiography, and, in some instances, PET with /sup 68/Ga-EDTA. PET with /sup 11/C-L-methionine permits better evaluation of the tumor extent and may affect preoperative grading.

  10. Differential diagnosis of AH109A tumor and inflammation by radioscintigraphy with L-[methyl-11C]methionine.

    PubMed

    Kubota, K; Matsuzawa, T; Fujiwara, T; Sato, T; Tada, M; Ido, T; Ishiwata, K

    1989-08-01

    For the evaluation of tumor imaging with L-[methyl-11C]methionine (11C-Met), a basic study on the differentiation of tumor from inflammation with 11C-Met and a comparison of the diagnostic value of the image with that obtained using 67Ga citrate, a conventional scintigraphic agent, are important. 11C-Met accumulations into inflammatory lesions, AH109A tumor and normal tissues of rats were examined by means of a tissue distribution study. Aseptic inflammatory lesions on the back of Donryu rats induced by croton oil and 1.5% carrageenan showed significantly lower accumulations of 11C-Met than the AH109A tumor. Histologically, croton oil induced granulomatous inflammation and carrageenan, acute exudative inflammation. Whole-body autoradiography with 14C-Met, a substitute for 11C-Met, was negative in the carrageenan lesion and showed a slightly increased activity at the periphery of the croton oil lesion, in contrast with the high tumor activity. Whole-body autoradiography with 67Ga citrate was performed to compare the imaging ability with that of 14C-Met; it showed high activities in the tumor, bone, and intestine, and a broad increased activity at the periphery of the croton oil lesion, but was negative in the carrageenan lesion. 11C-Met accumulations in the inflammations were very low and clinical application with positron emission tomography, should be useful for the differential diagnosis of tumor from inflammation. PMID:2511187

  11. Proton dose calculation based on in-air fluence measurements.

    PubMed

    Schaffner, Barbara

    2008-03-21

    Proton dose calculation algorithms--as well as photon and electron algorithms--are usually based on configuration measurements taken in a water phantom. The exceptions to this are proton dose calculation algorithms for modulated scanning beams. There, it is usual to measure the spot profiles in air. We use the concept of in-air configuration measurements also for scattering and uniform scanning (wobbling) proton delivery techniques. The dose calculation includes a separate step for the calculation of the in-air fluence distribution per energy layer. The in-air fluence calculation is specific to the technique and-to a lesser extent-design of the treatment machine. The actual dose calculation uses the in-air fluence as input and is generic for all proton machine designs and techniques. PMID:18367787

  12. Fluence dependence of deuterium retention in oxidized SS-316

    NASA Astrophysics Data System (ADS)

    Oya, Yasuhisa; Suzuki, Sachiko; Matsuyama, Masao; Hayashi, Takumi; Yamanishi, Toshihiko; Asakura, Yamato; Okuno, Kenji

    2011-10-01

    The ion fluence dependence of deuterium retention in SS-316 during oxidation at a temperature of 673 K was studied to evaluate the dynamics of deuterium retention in the oxide layer of SS-316. The correlation between the chemical state of stainless steel and deuterium retention was evaluated using XPS and TDS. It was found that the major deuterium desorption temperatures were located at around 660 K and 935 K, which correspond to the desorption of deuterium trapped as hydroxide. The deuterium retention increased with increasing deuterium ion fluence, since the deuterium retention as hydroxide increased significantly. However, retention saturated at an ion fluence of ˜2.5 × 10 21 D + m -2. The XPS result showed that FeOOD was formed on the surface, although pure Fe also remained in the oxide layer. These facts indicate the nature of the oxide layer have a key role in deuterium trapping behavior.

  13. Proton dose calculation based on in-air fluence measurements

    NASA Astrophysics Data System (ADS)

    Schaffner, Barbara

    2008-03-01

    Proton dose calculation algorithms—as well as photon and electron algorithms—are usually based on configuration measurements taken in a water phantom. The exceptions to this are proton dose calculation algorithms for modulated scanning beams. There, it is usual to measure the spot profiles in air. We use the concept of in-air configuration measurements also for scattering and uniform scanning (wobbling) proton delivery techniques. The dose calculation includes a separate step for the calculation of the in-air fluence distribution per energy layer. The in-air fluence calculation is specific to the technique and—to a lesser extent—design of the treatment machine. The actual dose calculation uses the in-air fluence as input and is generic for all proton machine designs and techniques.

  14. Production of radiohalogens and [11C]-methane at high specific activity

    NASA Astrophysics Data System (ADS)

    Nye, Jonathon Andrew

    2005-07-01

    The halogens, occupying Group VII of the periodic table, play an important role in the biochemical processes underlying health and disease. A variety of positron emitters covering a broad range of half-lives permit the imaging of the body's physiochemical behavior using PET. Neutron deficient isotopes of the halogen group can be produced by (p,n) reactions from enriched targets with low energy (<13MeV) biomedical cyclotrons. These cyclotrons are distributed relatively evenly throughout the United States at research institutions and commercial distribution sites (i.e., 100+ CTI RDS 11MeV proton cyclotrons). However, these sites concentrate on the core group of positron emitters: 15O, 13N, 11C, and primarily 18F-fluoride. The simplicity of the production process insures their role in the clinical/research environment, labeling H215 O, 13NH3, CH3-compounds and 18F-FDG. Halogens with half-lives longer than 18F have been avoided due to a combination of several factors, such as complexity of the target systems, expense of the enriched substrate, low reaction yields, and extensive post-processing to reclaim the target material. PET research over the last decade has forced a match between drug development and emerging small animal instrumentation, shifting focus to agents labeled with high specific activity 11CH3I and the long-lived radiohalogens, 76Br and 124I. A steady local supply of 18F-fluoride, 11C-methane, 76B-bromide, and 124I-iodide is essential to seize today's research opportunities or for limited distribution outside of our local area. To keep pace, new targetry developments are implemented to reliably produce these isotopes on a batch basis. The research presented details improvements on existing production methods for 18F-fluoride intended for nucleophilic substitution and high specific activity 11C-methane (→CH3I) for the N-methylation of a half-dozen neuroligands. A significant effort is placed on the novel use of low energy cyclotrons for the production

  15. Fluence field optimization for noise and dose objectives in CT

    SciTech Connect

    Bartolac, Steven; Graham, Sean; Siewerdsen, Jeff; Jaffray, David

    2011-05-15

    Purpose: Selecting the appropriate imaging technique in computed tomography (CT) inherently involves balancing the tradeoff between image quality and imaging dose. Modulation of the x-ray fluence field, laterally across the beam, and independently for each projection, may potentially meet user-prescribed, regional image quality objectives, while reducing radiation to the patient. The proposed approach, called fluence field modulated CT (FFMCT), parallels the approach commonly used in intensity-modulated radiation therapy (IMRT), except ''image quality plans'' replace the ''dose plans'' of IMRT. This work studies the potential noise and dose benefits of FFMCT via objective driven optimization of fluence fields. Methods: Experiments were carried out in simulation. Image quality plans were defined by specifying signal-to-noise ratio (SNR) criteria for regions of interest (ROIs) in simulated cylindrical and oblong water phantoms, and an anthropomorphic phantom with bone, air, and water equivalent regions. X-ray fluence field patterns were generated using a simulated annealing optimization method that attempts to achieve the spatially-dependent prescribed SNR criteria in the phantoms while limiting dose (to the volume or subvolumes). The resulting SNR and dose distributions were analyzed and compared to results using a bowtie filtered fluence field. Results: Compared to using a fixed bowtie filtered fluence, FFMCT achieved superior agreement with the target image quality objectives, and resulted in integral dose reductions ranging from 39 to 52%. Prioritizing dose constraints for specific regions of interest resulted in a preferential reduction of dose to those regions with some tradeoff in SNR, particularly where the target low dose regions overlapped with regions where high SNR was prescribed. The method appeared fairly robust under increased complexity and heterogeneity of the object structure. Conclusions: These results support that FFMCT has the potential to meet

  16. Monte Carlo correction factors for a Farmer 0.6 cm3 ion chamber dose measurement in the build-up region of the 6 MV clinical beam.

    PubMed

    Pena, J; Sánchez-Doblado, F; Capote, R; Terrón, J A; Gómez, F

    2006-03-21

    Reference dosimetry of photon fields is a well-established subject and currently available protocols (such as the IAEA TRS-398 and AAPM TG-51) provide methods for converting the ionization chamber (IC) reading into dose to water, provided reference conditions of charged particle equilibrium (CPE) are fulfilled. But these protocols cannot deal with the build-up region, where the lack of CPE limits the applicability of the cavity theorems and so the chamber correction factors become depth dependent. By explicitly including the IC geometry in the Monte Carlo simulations, depth-dependent dose correction factors are calculated for a PTW 30001 0.6 cm(3) ion chamber in the build-up region of the 6 MV photon beam. The corrected percentage depth dose (PDD) agrees within 2% with that measured using the NACP 02 plane-parallel ion chamber in the build-up region at depths greater than 0.4 cm, where the Farmer chamber wall reaches the phantom surface. PMID:16510960

  17. Nickel Foil as Transmutation Detector for Neutron Fluence Measurements

    NASA Astrophysics Data System (ADS)

    Klupák, Vít; Viererbl, Ladislav; Lahodová, Zdena; Šoltés, Jaroslav; Tomandl, Ivo; Kudějová, Petra

    2016-02-01

    Activation detectors are very often used for determination of the neutron fluence in reactor dosimetry. However, there are few disadvantages concerning these detectors; it is the demand of the knowledge of the irradiation history and a loss of information due to a radioactive decay in time. Transmutation detectors TMD could be a solution in this case. The transmutation detectors are materials in which stable or long-lived nuclides are produced by nuclear reactions with neutrons. From a measurement of concentration of these nuclides, neutron fluence can be evaluated regardless of the cooling time.

  18. A singly charged ion source for radioactive 11C ion acceleration

    NASA Astrophysics Data System (ADS)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K.

    2016-02-01

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  19. Transition metal mediated [(11) C]carbonylation reactions: recent advances and applications.

    PubMed

    Kealey, Steven; Gee, Antony; Miller, Philip W

    2014-04-01

    [(11) C]Carbon monoxide is undoubtedly a highly versatile radiolabelling synthon with many potential applications for the synthesis of positron emission tomography (PET) tracer molecules and functional groups, but why has it not found more applications in the PET radiolabelling arena? Today, (11) CO radiolabelling is still primarily viewed as a niche area; however, there are signs that this is beginning to change as some of the technical and chemistry challenges of producing, handling and reacting (11) CO are overcome. This mini review covers the more recent developments of (11) CO-labelling chemistry and is focused on palladium and rhodium-mediated carbonylation reactions that are growing in importance and finding wider application for carbon-11 PET radiotracer development. PMID:24425679

  20. Mannosylated polyion complexes for in vivo gene delivery into CD11c(+) dendritic cells.

    PubMed

    Raviv, Lior; Jaron-Mendelson, Michal; David, Ayelet

    2015-02-01

    Dendritic cells (DCs) possess unique abilities in initiating primary immune responses and thus represent prime targets for DNA-based vaccinations. Here, we describe the design and synthesis of mannosylated polyion complexes (PICs) composed of cationic polyethylenimine (PEI) and hydrophilic polyethylene glycol (PEG) segments, and bearing mono- and trivalent mannose as a ligand for targeting mannose receptor (MR/CD206)-positive DCs. Amino-terminated mannose (Man)-containing ligands in mono- and trivalent presentations (Man- and Man3-, respectively) were prepared and conjugated to PEG via an N-hydroxysuccinimide (NHS)-activated terminal. Thiolated PEI was conjugated to the mannosylated PEG via the maleimide (MAL)-activated terminal. The resulting positively charged diblock copolymers bearing mannoses (Man-PEG-b-PEI and Man3-PEG-b-PEI) were self-assembled with DNA to form PICs with lower surface charge than did their PEI building block and mean hydrodynamic diameters in the range of 100-450 nm, depending on the N/P ratio. Man3-PEG-b-PEI demonstrated a 3-4-fold greater transfection efficiency in MR-positive dendritic cell lines (THP-1, DC2.4), relative to Man-PEG-b-PEI, exhibited low cytotoxicity when compared with PEI, and showed low transfection efficiency in nondendritic HeLa cells. In preliminary in vivo experiments, Man-PEG-b-PEI/DNA and Man3-PEG-b-PEI/DNA demonstrated 2-3-fold higher gene delivery efficiency into CD11c(+) DCs collected from inguinal lymph nodes of C57/BL6 mice, when compared to PEI/DNA complexes, as shown by GFP expression measurements, 24 h post subcutaneous injection. The results indicate that the mannosylated PICs are a safe and effective gene delivery system, showing in vivo specificity toward CD11c(+) DCs. PMID:25531245

  1. Alzheimer's disease detection using 11C-PiB with improved partial volume effect correction

    NASA Astrophysics Data System (ADS)

    Raniga, Parnesh; Bourgeat, Pierrick; Fripp, Jurgen; Acosta, Oscar; Ourselin, Sebastien; Rowe, Christopher; Villemagne, Victor L.; Salvado, Olivier

    2009-02-01

    Despite the increasing use of 11C-PiB in research into Alzheimer's disease (AD), there are few standardized analysis procedures that have been reported or published. This is especially true with regards to partial volume effects (PVE) and partial volume correction. Due to the nature of PET physics and acquisition, PET images exhibit relatively low spatial resolution compared to other modalities, resulting in bias of quantitative results. Although previous studies have applied PVE correction techniques on 11C-PiB data, the results have not been quantitatively evaluated and compared against uncorrected data. The aim of this study is threefold. Firstly, a realistic synthetic phantom was created to quantify PVE. Secondly, MRI partial volume estimate segmentations were used to improve voxel-based PVE correction instead of using hard segmentations. Thirdly, quantification of PVE correction was evaluated on 34 subjects (AD=10, Normal Controls (NC)=24), including 12 PiB positive NC. Regional analysis was performed using the Anatomical Automatic Labeling (AAL) template, which was registered to each patient. Regions of interest were restricted to the gray matter (GM) defined by the MR segmentation. Average normalized intensity of the neocortex and selected regions were used to evaluate the discrimination power between AD and NC both with and without PVE correction. Receiver Operating Characteristic (ROC) curves were computed for the binary discrimination task. The phantom study revealed signal losses due to PVE between 10 to 40 % which were mostly recovered to within 5% after correction. Better classification was achieved after PVE correction, resulting in higher areas under ROC curves.

  2. Transcriptional profiling of CD11c-positive microglia accumulating around amyloid plaques in a mouse model for Alzheimer's disease.

    PubMed

    Kamphuis, Willem; Kooijman, Lieneke; Schetters, Sjoerd; Orre, Marie; Hol, Elly M

    2016-10-01

    Amyloid plaques in Alzheimer's disease (AD) mice are surrounded by activated microglia. The functional role of microglia activation in AD is not well understood; both detrimental and beneficial effects on AD progression have been reported. Here we show that the population of activated microglia in the cortex of the APPswe/PS1dE9 mouse AD model is divided into a CD11c-positive and a CD11c-negative subpopulation. Cd11c transcript levels and number of CD11c-positive microglia increase sharply when plaques start to occur and both parameters continue to rise in parallel with the age-related increasing plaque load. CD11c cells are localized near plaques at all stages of the disease development and constitute 23% of all activated microglia. No differences between these two populations were found in terms of proliferation, immunostaining intensity of Iba1, MHC class II, CD45, or immunoproteasome subunit LMP7/β5i. Comparison of the transcriptome of isolated CD11c-positive and CD11c-negative microglia from the cortex of aged APPswe/PS1dE9 with WT microglia showed that gene expression changes had a similar general pattern. However, a differential expression was found for genes involved in immune signaling (Il6, S100a8/Mrp8, S100a9/Mrp14, Spp1, Igf1), lysosome activation, and carbohydrate- and cholesterol/lipid-metabolism (Apoe). In addition, the increased expression of Gpnmb/DC-HIL, Tm7sf4/DC-STAMP, and Gp49a/Lilrb4, suggests a suppressive/tolerizing influence of CD11c cells. We show that amyloid plaques in the APP/PS1 model are associated with two distinct populations of activated microglia: CD11c-positive and CD11c-negative cells. Our findings imply that CD11c-positive microglia can potentially counteract amyloid deposition via increased Aβ-uptake and degradation, and by containing the inflammatory response. PMID:27425031

  3. Tracer kinetic modeling of [(11)C]AFM, a new PET imaging agent for the serotonin transporter.

    PubMed

    Naganawa, Mika; Nabulsi, Nabeel; Planeta, Beata; Gallezot, Jean-Dominique; Lin, Shu-Fei; Najafzadeh, Soheila; Williams, Wendol; Ropchan, Jim; Labaree, David; Neumeister, Alexander; Huang, Yiyun; Carson, Richard E

    2013-12-01

    [(11)C]AFM, or [(11)C]2-[2-(dimethylaminomethyl)phenylthio]-5-fluoromethylphenylamine, is a new positron emission tomography (PET) radioligand with high affinity and selectivity for the serotonin transporter (SERT). The purpose of this study was to determine the most appropriate kinetic model to quantify [(11)C]AFM binding in the healthy human brain. Positron emission tomography data and arterial input functions were acquired from 10 subjects. Compartmental modeling and the multilinear analysis-1(MA1) method were tested using the arterial input functions. The one-tissue model showed a lack of fit in low-binding regions, and the two-tissue model failed to estimate parameters reliably. Regional time-activity curves were well described by MA1. The rank order of [(11)C]AFM binding potential (BPND) matched well with the known regional SERT densities. For routine use of [(11)C]AFM, several noninvasive methods for quantification of regional binding were evaluated, including simplified reference tissue models (SRTM and SRTM2), and multilinear reference tissue models (MRTM and MRTM2). The best methods for region of interest (ROI) analysis were MA1, MRTM2, and SRTM2, with fixed population kinetic values ( or b') for the reference methods. The MA1 and MRTM2 methods were best for parametric imaging. These results showed that [(11)C]AFM is a suitable PET radioligand to image and quantify SERT in humans. PMID:23921898

  4. Optimization and Biodistribution of [(11)C]-TKF, An Analog of Tau Protein Imaging Agent [(18)F]-THK523.

    PubMed

    Kong, Yanyan; Guan, Yihui; Hua, Fengchun; Zhang, Zhengwei; Lu, Xiuhong; Zhu, Tengfang; Zhao, Bizeng; Zhu, Jianhua; Li, Cong; Chen, Jian

    2016-01-01

    The quantification of neurofibrillary tangles (NFTs) using specific PET tracers can facilitate the diagnosis of Alzheimer's disease (AD) and allow monitoring of disease progression and treatment efficacy. [(18)F]-THK523 has shown high affinity and selectivity for tau pathology. However, its high retention in white matter, which makes simple visual inspection difficult, may limit its use in research or clinical settings. In this paper, we optimized the automated radiosynthesis of [(11)C]-TKF and evaluated its biodistribution and toxicity in C57 mice. [(11)C]-TKF can be made by reaction precursor with [(11)C]MeOTf or (11)CH₃I, but [(11)C]MeOTf will give us higher labeling yields and specific activity. [(11)C]-TKF presented better brain uptake in normal mouse than [(18)F]-THK523 (3.23% ± 1.25% ID·g(-1) vs. 2.62% ± 0.39% ID·g(-1) at 2 min post-injection). The acute toxicity studies of [(11)C]-TKF were unremarkable. PMID:27527142

  5. Quantification of the novel N-methyl-d-aspartate receptor ligand [11C]GMOM in man.

    PubMed

    van der Doef, Thalia F; Golla, Sandeep Sv; Klein, Pieter J; Oropeza-Seguias, Gisela M; Schuit, Robert C; Metaxas, Athanasios; Jobse, Ellen; Schwarte, Lothar A; Windhorst, Albert D; Lammertsma, Adriaan A; van Berckel, Bart Nm; Boellaard, Ronald

    2016-06-01

    [(11)C]GMOM (carbon-11 labeled N-(2-chloro-5-thiomethylphenyl)-N'-(3-[(11)C]methoxy-phenyl)-N'-methylguanidine) is a PET ligand that binds to the N-methyl-d-aspartate receptor with high specificity and affinity. The purpose of this first in human study was to evaluate kinetics of [(11)C]GMOM in the healthy human brain and to identify the optimal pharmacokinetic model for quantifying these kinetics, both before and after a pharmacological dose of S-ketamine. Dynamic 90 min [(11)C]GMOM PET scans were obtained from 10 subjects. In six of the 10 subjects, a second PET scan was performed following an S-ketamine challenge. Metabolite corrected plasma input functions were obtained for all scans. Regional time activity curves were fitted to various single- and two-tissue compartment models. Best fits were obtained using a two-tissue irreversible model with blood volume parameter. The highest net influx rate (Ki) of [(11)C]GMOM was observed in regions with high N-methyl-d-aspartate receptor density, such as hippocampus and thalamus. A significant reduction in the Ki was observed for the entire brain after administration of ketamine, suggesting specific binding to the N-methyl-d-aspartate receptors. This initial study suggests that the [(11)C]GMOM could be used for quantification of N-methyl-d-aspartate receptors. PMID:26661185

  6. Quantification of the novel N-methyl-d-aspartate receptor ligand [11C]GMOM in man

    PubMed Central

    van der Doef, Thalia F; Klein, Pieter J; Oropeza-Seguias, Gisela M; Schuit, Robert C; Metaxas, Athanasios; Jobse, Ellen; Schwarte, Lothar A; Windhorst, Albert D; Lammertsma, Adriaan A; van Berckel, Bart NM; Boellaard, Ronald

    2015-01-01

    [11C]GMOM (carbon-11 labeled N-(2-chloro-5-thiomethylphenyl)-N′-(3-[11C]methoxy-phenyl)-N′-methylguanidine) is a PET ligand that binds to the N-methyl-d-aspartate receptor with high specificity and affinity. The purpose of this first in human study was to evaluate kinetics of [11C]GMOM in the healthy human brain and to identify the optimal pharmacokinetic model for quantifying these kinetics, both before and after a pharmacological dose of S-ketamine. Dynamic 90 min [11C]GMOM PET scans were obtained from 10 subjects. In six of the 10 subjects, a second PET scan was performed following an S-ketamine challenge. Metabolite corrected plasma input functions were obtained for all scans. Regional time activity curves were fitted to various single- and two-tissue compartment models. Best fits were obtained using a two-tissue irreversible model with blood volume parameter. The highest net influx rate (Ki) of [11C]GMOM was observed in regions with high N-methyl-d-aspartate receptor density, such as hippocampus and thalamus. A significant reduction in the Ki was observed for the entire brain after administration of ketamine, suggesting specific binding to the N-methyl-d-aspartate receptors. This initial study suggests that the [11C]GMOM could be used for quantification of N-methyl-d-aspartate receptors. PMID:26661185

  7. The effect of nicotine on striatal dopamine release in man: A [11C]raclopride PET study.

    PubMed

    Montgomery, Andrew J; Lingford-Hughes, Anne R; Egerton, Alice; Nutt, David J; Grasby, Paul M

    2007-08-01

    In common with many addictive substances and behaviors nicotine activates the mesolimbic dopaminergic system. Brain microdialysis studies in rodents have consistently shown increases in extrasynaptic DA levels in the striatum after administration of nicotine but PET experiments in primates have given contradicting results. A recent PET study assessing the effect of smoking in humans showed no change in [(11)C]raclopride binding in the brain, but did find that "hedonia" correlated with a reduction in [(11)C]raclopride binding suggesting that DA may mediate the positive reinforcing effects of nicotine. In this experiment we measured the effect of nicotine, administered via a nasal spray, on DA release using [(11)C]raclopride PET, in 10 regular smokers. There was no overall change in [(11)C]raclopride binding after nicotine administration in any of the striatal regions examined. However, the individual change in [(11)C]raclopride binding correlated with change in subjective measures of "amused" and "happiness" in the associative striatum (AST) and sensorimotor striatum (SMST). Nicotine concentration correlated negatively with change in BP in the limbic striatum. Nicotine had significant effects on cardiovascular measures including pulse rate, systolic blood pressure (BPr), and diastolic BPr. Baseline [(11)C]raclopride binding potential (BP) in the AST correlated negatively with the Fagerström score, an index of nicotine dependence. These results support a role for the DA system in nicotine addiction, but reveal a more complex relationship than suggested by studies in animals. PMID:17492764

  8. Comparison of autologous 111In-leukocytes, 18F-FDG, 11C-methionine, 11C-PK11195 and 68Ga-citrate for diagnostic nuclear imaging in a juvenile porcine haematogenous staphylococcus aureus osteomyelitis model

    PubMed Central

    Nielsen, Ole L; Afzelius, Pia; Bender, Dirk; Schønheyder, Henrik C; Leifsson, Páll S; Nielsen, Karin M; Larsen, Jytte O; Jensen, Svend B; Alstrup, Aage KO

    2015-01-01

    The aim of this study was to compare 111In-labeled leukocyte single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) to PET with tracers that potentially could improve detection of osteomyelitis. We chose 11C-methionine, 11C-PK11195 and 68Ga-citrate and validated their diagnostic utility in a porcine haematogenous osteomyelitis model. Four juvenile 14-15 weeks old female pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus using a sequential scan protocol with 18F-FDG, 68Ga-citrate, 11C-methionine, 11C-PK11195, 99mTc-Nanocoll and 111In-labelled autologous leukocytes. This was followed by necropsy of the pigs and gross pathology, histopathology and microbial examination. The pigs developed a total of five osteomyelitis lesions, five lesions characterized as abscesses/cellulitis, arthritis in three joints and five enlarged lymph nodes. None of the tracers accumulated in joints with arthritis. By comparing the 10 infectious lesions, 18F-FDG accumulated in nine, 111In-leukocytes in eight, 11C-methionine in six, 68Ga-citrate in four and 11C-PK11195 accumulated in only one lesion. Overall, 18F-FDG PET was superior to 111In-leukocyte SPECT in marking infectious and proliferative, i.e. hyperplastic, lesions. However, leukocyte SPECT was performed as early scans, approximately 6 h after injection of the leukocytes, to match the requirements of the 18 h long scan protocol. 11C-methionine and possibly 68Ga-citrate may be useful for diagnosis of soft issue lesions. PMID:25973338

  9. Comparison of autologous (111)In-leukocytes, (18)F-FDG, (11)C-methionine, (11)C-PK11195 and (68)Ga-citrate for diagnostic nuclear imaging in a juvenile porcine haematogenous staphylococcus aureus osteomyelitis model.

    PubMed

    Nielsen, Ole L; Afzelius, Pia; Bender, Dirk; Schønheyder, Henrik C; Leifsson, Páll S; Nielsen, Karin M; Larsen, Jytte O; Jensen, Svend B; Alstrup, Aage Ko

    2015-01-01

    The aim of this study was to compare (111)In-labeled leukocyte single-photon emission computed tomography (SPECT) and (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) to PET with tracers that potentially could improve detection of osteomyelitis. We chose (11)C-methionine, (11)C-PK11195 and (68)Ga-citrate and validated their diagnostic utility in a porcine haematogenous osteomyelitis model. Four juvenile 14-15 weeks old female pigs were scanned seven days after intra-arterial inoculation in the right femoral artery with a porcine strain of Staphylococcus aureus using a sequential scan protocol with (18)F-FDG, (68)Ga-citrate, (11)C-methionine, (11)C-PK11195, (99m)Tc-Nanocoll and (111)In-labelled autologous leukocytes. This was followed by necropsy of the pigs and gross pathology, histopathology and microbial examination. The pigs developed a total of five osteomyelitis lesions, five lesions characterized as abscesses/cellulitis, arthritis in three joints and five enlarged lymph nodes. None of the tracers accumulated in joints with arthritis. By comparing the 10 infectious lesions, (18)F-FDG accumulated in nine, (111)In-leukocytes in eight, (11)C-methionine in six, (68)Ga-citrate in four and (11)C-PK11195 accumulated in only one lesion. Overall, (18)F-FDG PET was superior to (111)In-leukocyte SPECT in marking infectious and proliferative, i.e. hyperplastic, lesions. However, leukocyte SPECT was performed as early scans, approximately 6 h after injection of the leukocytes, to match the requirements of the 18 h long scan protocol. (11)C-methionine and possibly (68)Ga-citrate may be useful for diagnosis of soft issue lesions. PMID:25973338

  10. [{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%.

  11. An Improved Antagonist Radiotracer for the Kappa Opioid Receptor: Synthesis and Characterization of 11C-LY2459989

    PubMed Central

    Zheng, Ming-Qiang; Kim, Su Jin; Holden, Daniel; Lin, Shu-fei; Need, Anne; Rash, Karen; Barth, Vanessa; Mitch, Charles; Navarro, Antonio; Kapinos, Michael; Maloney, Kathleen; Ropchan, Jim; Carson, Richard E.; Huang, Yiyun

    2016-01-01

    The kappa opioid receptors (KOR) are implicated in a number of neuropsychiatric diseases and addictive disorders. Positron Emission Tomography (PET) with radioligands provides a means to image the KOR in vivo and investigate its function in health and disease. The purpose of this study was to develop the selective KOR antagonist 11C-LY2459989 as a PET radioligand and characterize its imaging performance in non-human primates. Methods LY2459989 was synthesized and assayed for in vitro binding to opioid receptors. Ex vivo studies in rodents were conducted to assess its potential as a tracer candidate. 11C-LY2459989 was synthesized by reaction of its iodophenyl precursor with 11C-cyanide followed by partial hydrolysis of the resulting 11C-cyanophenyl intermediate. Imaging experiments with 11C-LY2459989 were carried out in rhesus monkeys with arterial input function measurement. Imaging data were analyzed with kinetic models to derive in vivo binding parameters. Results LY2459989 is a full antagonist with high binding affinity and selectivity for KOR (Ki = 0.18, 7.68, and 91.3 nM, respectively, for κ, μ, and δ receptors). Ex vivo studies in rats indicated LY2459989 as an appropriate tracer candidate with high specific binding signals, and confirmed its KOR binding selectivity in vivo. 11C-LY2459989 was synthesized in high radiochemical purity and good specific activity. In rhesus monkeys, 11C-LY2459989 displayed a fast rate of peripheral metabolism. Similarly, 11C-LY2459989 displayed fast uptake kinetics in the brain and an uptake pattern consistent with the distribution of KOR in primates. Pretreatment with naloxone (1 mg/kg, i.v.) resulted in a uniform distribution of radioactivity in the brain. Further, specific binding of 11C-LY2459989 was dose-dependently reduced by the selective KOR antagonist LY2456302 and the unlabeled LY2459989. Regional binding potential (BPND) values derived from the multilinear analysis method (MA1), as a measure of in vivo specific

  12. Low-fluence carbon dioxide laser irradiation of lentigines

    SciTech Connect

    Dover, J.S.; Smoller, B.R.; Stern, R.S.; Rosen, S.; Arndt, K.A.

    1988-08-01

    Low-fluence carbon dioxide (CO2) laser irradiation of skin has previously been shown to induce damage limited primarily to the epidermis. To evaluate whether this technique was therapeutically effective for pigmented epidermal lesions, ten lentigines caused by methoxsalen and ultraviolet light therapy were treated in one patient using the CO2 laser at fluences ranging from 3.0 to 7.7 J/cm2 for 0.1-s exposures with 4.5-mm spot size. Based on substantial clearing in seven of ten lesions treated, 146 solar lentigines were treated in five patients at fluences of 3.0, 3.7, or 4.4 J/cm2. Biopsies were performed on a total of 30 lesions immediately and 24 hours, seven days, and six weeks after irradiation. Of 125 lesions followed up clinically for six weeks, 12 cleared completely, 81 lightened substantially, and 28 remained unchanged. Only two demonstrated atrophic change. Hyperpigmentation or hypopigmentation did not occur. All lesions that improved had been treated at 3.7 or 4.4 J/cm2. Immediate histologic injury consisted of vacuolar and spindly change and subsequent vesiculation limited to the basilar epidermis. Twenty-four hours later there was epidermal necrosis with regeneration, 0.1 mm of dermal basophilia and stromal condensation, and a mild inflammatory infiltrate. These alterations were dose-dependent, with near complete epidermal necrosis and superficial dermal involvement at the highest fluence, and only focal epidermal necrosis at the lowest. At seven days, epidermal regeneration was complete with traces of melanin remaining in keratinocytes. Melanophages first appeared at seven days and persisted at six weeks, by which time the inflammatory infiltrate had cleared. No lentiginous proliferation was evident and epidermal pigmentation had become normal. Low-fluence CO2 laser irradiation is an effective means of damaging the epidermis with only minimal dermal change.

  13. Implementation and validation of a fluence pencil kernels model for GaN-based dosimetry in photon beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Wang, Ruoxi; Pittet, Patrick; Ribouton, Julien; Lu, Guo-Neng; Chaikh, Abdulhamid; Ahnesjö, Anders

    2013-10-01

    Gallium nitride (GaN), a direct-gap semiconductor that is radioluminescent, can be used as a transducer yielding a high signal from a small detecting volume and thus potentially suitable for use in small fields and for high dose gradients. A common drawback of semiconductor dosimeters with effective atomic numbers higher than soft tissues is that their responses depend on the presence of low energy photons for which the photoelectric cross section varies strongly with atomic number, which may affect the accuracy of dosimetric measurements. To tackle this ‘over-response’ issue, we propose a model for GaN-based dosimetry with readout correction. The local photon spectrum is calculated by convolving fluence pencil kernel spectra with the beam aperture fluence distribution. The response of a GaN detector is modelled by combining large cavity theory and small cavity theory for the low and high energy components of the local spectrum. Monte Carlo simulations are employed for determination of specific correction factors for different GaN transducer sizes and irradiation conditions. Some model parameters such as the cut-off energy and partitioning energy are discussed. The accuracy of the GaN dosimetric response model has been evaluated for tissue phantom ratio experiments along the central axis. These experiments have shown that calculated and measured GaN responses stay within ±3% at all depths beyond the build-up depth. The calculated GaN response factor is also in good agreement with measured data (±2.5%). The validated model with response compensation improves significantly the accuracy of dosimetric measurements: below 2.5% deviation as compared to 13% without compensation, for a 10 × 10 cm2 field, at depth from 1.5 to 22 cm.

  14. [11C]acetate PET Imaging is not Always Associated with Increased Lipogenesis in Hepatocellular Carcinoma in Mice

    PubMed Central

    Li, Lei; Che, Li; Wang, Chunmei; Blecha, Joseph E.; Li, Xiaolei; VanBrocklin, Henry F.; Calvisi, Diego F.; Puchowicz, Michelle; Chen, Xin; Seo, Youngho

    2015-01-01

    Purpose Altered metabolism, including increased glycolysis and de novo lipogenesis, is one of the hallmarks of cancer. Radiolabeled nutrients, including glucose and acetate, are extensively used for the detection of various tumors, including hepatocellular carcinomas (HCCs). High signal of [11C]acetate positron emission tomography (PET) in tumors is often considered to be associated with increased expression of Fatty Acid Synthase (FASN) and increased de novo lipogenesis in tumor tissues. Defining a subset of tumors with increased [11C]acetate PET signal and thus increased lipogenesis was suggested to help select a group of patients, who may benefit from lipogenesis-targeting therapies. Procedures To investigate whether [11C]acetate PET imaging is truly associated with increased de novo lipogenesis along with hepatocarcinogenesis, we performed [11C]acetate PET imaging in wildtype mice as well as two mouse HCC models, induced by myrAKT/RasV12 (AKT/Ras) and PIK3CA1047R/c-Met (PI3K/Met) oncogene combinations. In addition, we analyzed FASN expression and de novo lipogenesis rate in these mouse liver tissues. Results We found that while HCCs induced by AKT/Ras co-expression showed high levels of [11C]acetate PET signal compared to normal liver, HCCs induced by PI3K/Met overexpression did not. Intriguingly, elevated FASN expression and increased de novo lipogenesis rate were observed in both AKT/Ras and PI3K/Met HCCs. Conclusion Altogether, our study suggests that [11C]acetate PET imaging can be a useful tool for imaging of a subset of HCCs. However, at molecular level, the increased [11C]acetate PET imaging is not always associated with increased FASN expression or de novo lipogenesis. PMID:26567114

  15. In vivo ketamine-induced changes in [11C]ABP688 binding to metabotropic glutamate receptors subtype 5

    PubMed Central

    DeLorenzo, Christine; DellaGioia, Nicole; Bloch, Michael; Sanacora, Gerard; Nabulsi, Nabeel; Abdallah, Chadi; Yang, Jie; Wen, Ruofeng; Mann, J. John; Krystal, John H.; Parsey, Ramin V.; Carson, Richard E.; Esterlis, Irina

    2014-01-01

    Background At subanesthetic doses, ketamine, an N-Methyl-D-aspartate (NMDA) glutamate receptor antagonist, increases glutamate release. Here, we imaged the acute effect of ketamine on brain metabotropic glutamatergic receptors subtype 5 (mGluR5) with a high affinity PET ligand [11C]ABP688 ((E)-3-((6-methylpyridin-2-yl)ethynyl)-cyclohex-2-enone-O-11C-methyl-oxime), a negative allosteric modulator of mGluR5. Methods Ten healthy nonsmoking human volunteers (34±13 years old) received two [11C]ABP688 PET scans on the same day – before (scan 1) and during i.v. ketamine administration (0.23mg/kg over 1min, then 0.58mg/kg over 1h; scan 2). PET data were acquired for 90 min immediately following [11C]ABP688 bolus injection. Input functions were obtained through arterial blood sampling with metabolite analysis. Results A significant reduction in [11C]ABP688 volume of distribution (VT) was observed in scan 2 relative to scan 1 of 21.3 ± 21.4%, on average, in the anterior cingulate, medial prefrontal cortex, orbital prefrontal cortex, ventral striatum, parietal lobe, dorsal putamen, dorsal caudate, amygdala, and hippocampus. There was a significant increase in measurements of dissociative state after ketamine initiation (p<0.05) that resolved after completion of the scan. Discussion This study provides first evidence that ketamine administration decreases [11C]ABP688 binding in vivo in human subjects. Results suggest that [11C]ABP688 binding is sensitive to ketamine-induced effects, although the high individual variation in ketamine response requires further examination. PMID:25156701

  16. Rethinking the Concepts of Fluence (UV Dose) and Fluence Rate: The Importance of Photon-based Units - A Systemic Review.

    PubMed

    Bolton, James R; Mayor-Smith, Ian; Linden, Karl G

    2015-11-01

    After a critical review of the fundamental equations describing photobiological and photochemical processes occurring in a medium exposed to a quasi-collimated monochromatic UV light beam, the analysis in this review is extended to analogous processes driven by polychromatic UV light, such as that emitted by medium pressure mercury-vapor arc lamps. The analysis is based on the Second Law of Photochemistry, namely that all photochemical events must be independent, and the rate of such events must be proportional to the rate of photon absorption. A consistent application of the Second Law of Photochemistry leads to a concept change; hence it is proposed herein to use photon fluence and photon fluence rate, rather than fluence (UV dose) and fluence rate, respectively, in the analysis and interpretation of photobiological and photochemical processes. As a consequence, many equations that have been used in the past must be revised, and some experimental information (e.g. action spectra) needs to be re-analyzed. PMID:26277478

  17. Increased striatal dopamine release in Parkinsonian patients with pathological gambling: a [11C] raclopride PET study

    PubMed Central

    Steeves, T. D. L.; Miyasaki, J.; Zurowski, M.; Lang, A. E.; Pellecchia, G.; Van Eimeren, T.; Rusjan, P.; Houle, S.; Strafella, A. P.

    2012-01-01

    Pathological gambling is an impulse control disorder reported in association with dopamine agonists used to treat Parkinson’s disease. Although impulse control disorders are conceptualized as lying within the spectrum of addictions, little neurobiological evidence exists to support this belief. Functional imaging studies have consistently demonstrated abnormalities of dopaminergic function in patients with drug addictions, but to date no study has specifically evaluated dopaminergic function in Parkinson’s disease patients with impulse control disorders. We describe results of a [11C] raclopride positron emission tomography (PET) study comparing dopaminergic function during gambling in Parkinson’s disease patients, with and without pathological gambling, following dopamine agonists. Patients with pathological gambling demonstrated greater decreases in binding potential in the ventral striatum during gambling (13.9%) than control patients (8.1%), likely reflecting greater dopaminergic release. Ventral striatal bindings at baseline during control task were also lower in patients with pathological gambling. Although prior imaging studies suggest that abnormality in dopaminergic binding and dopamine release may be markers of vulnerability to addiction, this study presents the first evidence of these phenomena in pathological gambling. The emergence of pathological gambling in a number of Parkinson’s disease patients may provide a model into the pathophysiology of this disorder. PMID:19346328

  18. (11)C-PBR28 binding to translocator protein increases with progression of Alzheimer's disease.

    PubMed

    Kreisl, William C; Lyoo, Chul Hyoung; Liow, Jeih-San; Wei, Monica; Snow, Joseph; Page, Emily; Jenko, Kimberly J; Morse, Cheryl L; Zoghbi, Sami S; Pike, Victor W; Turner, R Scott; Innis, Robert B

    2016-08-01

    This longitudinal study sought to determine whether the 18 kDa translocator protein (TSPO), a marker of neuroinflammation, increases over time in Alzheimer's disease. Positron emission tomography imaging with the TSPO radioligand (11)C-PBR28 was performed at baseline and after a median follow-up of 2.7 years in 14 amyloid-positive patients and 8 amyloid-negative controls. Patients had a greater increase in TSPO binding than controls in inferior parietal lobule, precuneus, occipital cortex, hippocampus, entorhinal cortex, and combined middle and inferior temporal cortex. TSPO binding in temporoparietal regions increased from 3.9% to 6.3% per annum in patients, but ranged from -0.5% to 1% per annum in controls. The change in TSPO binding correlated with cognitive worsening on clinical dementia rating scale-sum of boxes and reduced cortical volume. The annual rate of increased TSPO binding in temporoparietal regions was about 5-fold higher in patients with clinical progression (n = 9) compared with those who did not progress (n = 5). TSPO may serve as a biomarker of Alzheimer's progression and response to anti-inflammatory therapies. PMID:27318133

  19. Build-up and wash-off dynamics of atmospherically derived Cu, Pb, Zn and TSS in stormwater runoff as a function of meteorological characteristics.

    PubMed

    Murphy, Louise U; Cochrane, Thomas A; O'Sullivan, Aisling

    2015-03-01

    Atmospheric pollutants deposited on impermeable surfaces can be an important source of pollutants to stormwater runoff; however, modelling atmospheric pollutant loads in runoff has rarely been done, because of the challenges and uncertainties in monitoring their contribution. To overcome this, impermeable concrete boards (≈ 1m(2)) were deployed for 11 months in different locations within an urban area (industrial, residential and airside) throughout Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Runoff was analysed for total and dissolved Cu, Zn, Pb, and total suspended solids (TSS). Mixed-effect regression models were developed to simulate atmospheric pollutant loads in stormwater runoff. In addition, the models were used to explain the influence of different meteorological characteristics (e.g. antecedent dry days and rain depth) on pollutant build-up and wash-off dynamics. The models predicted approximately 53% to 69% of the variation in pollutant loads and were successful in predicting pollutant-load trends over time which can be useful for general stormwater planning processes. Results from the models illustrated the importance of antecedent dry days on pollutant build-up. Furthermore, results indicated that peak rainfall intensity and rain duration had a significant relationship with TSS and total Pb, whereas, rain depth had a significant relationship with total Cu and total Zn. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration had a greater influence when the pollutants were predominantly in their particulate phase. Conversely, rain depth exerted a greater influence when a high fraction of the pollutants were predominantly in their dissolved phase. For all pollutants, the models were represented by a log-arctan relationship for pollutant build-up and a log-log relationship for pollutant wash

  20. Imaging human brown adipose tissue under room temperature conditions with 11C-MRB, a selective norepinephrine transporter PET ligand

    PubMed Central

    Hwang, Janice J.; Yeckel, Catherine W.; Gallezot, Jean-Dominique; Aguiar, Renata Belfort-De; Ersahin, Devrim; Gao, Hong; Kapinos, Michael; Nabulsi, Nabeel; Huang, Yiyun; Cheng, David; Carson, Richard E.; Sherwin, Robert; Ding, Yu-Shin

    2015-01-01

    Introduction Brown adipose tissue (BAT) plays a critical role in adaptive thermogenesis and is tightly regulated by the sympathetic nervous system (SNS). However, current BAT imaging modalities require cold stimulation and are often unreliable to detect BAT in the basal state, at room temperature (RT). We have shown previously that BAT can be detected in rodents under both RT and cold conditions with 11C-MRB ((S,S)-11C-O-methylreboxetine), a highly selective ligand for the norepinephrine transporter (NET). Here, we evaluate this novel approach for BAT detection in adult humans under RT conditions. Methods Ten healthy, Caucasian subjects (5 M: age 24.6±2.6, BMI 21.6±2.7 kg/m2; 5 F: age 25.4±2.1, BMI 22.1±1.0 kg/m2) underwent 11C-MRB PET-CT imaging for cervical/supraclavicular BAT under RT and cold-stimulated conditions (RPCM Cool vest; enthalpy 15°C) compared to 18F-FDG PET-CT imaging. Uptake of 11C-MRB, was quantified as the distribution volume ratio (DVR) using the occipital cortex as a low NET density reference region. Total body fat and lean body mass were assessed via bioelectrical impedance analysis. Results As expected, 18F-FDG uptake in BAT was difficult to identify at RT but easily detected with cold stimulation (p=0.01). In contrast, BAT 11C-MRB uptake (also normalized for muscle) was equally evident under both RT and cold conditions (BAT DVR: RT 1.0±0.3 vs. cold 1.1±0.3, p=0.31; BAT/muscle DVR: RT 2.3±0.7 vs. cold 2.5±0.5, p=0.61). Importantly, BAT DVR and BAT/muscle DVR of 11C-MRB at RT correlated positively with core body temperature (r=0.76, p=0.05 and r=0.92, p=0.004, respectively), a relationship not observed with 18F-FDG (p=0.63). Furthermore, there were gender differences in 11C-MRB uptake in response to cold (p=0.03), which reflected significant differences in the change in 11C-MRB as a function of both body composition and body temperature. Conclusions Unlike 18F-FDG, the uptake of 11C-MRB in BAT offers a unique opportunity to

  1. Compensator models for fluence field modulated computed tomography

    SciTech Connect

    Bartolac, Steven; Jaffray, David

    2013-12-15

    Purpose: Fluence field modulated computed tomography (FFMCT) presents a novel approach for acquiring CT images, whereby a patient model guides dynamically changing fluence patterns in an attempt to achieve task-based, user-prescribed, regional variations in image quality, while also controlling dose to the patient. This work aims to compare the relative effectiveness of FFMCT applied to different thoracic imaging tasks (routine diagnostic CT, lung cancer screening, and cardiac CT) when the modulator is subject to limiting constraints, such as might be present in realistic implementations.Methods: An image quality plan was defined for a simulated anthropomorphic chest slice, including regions of high and low image quality, for each of the thoracic imaging tasks. Modulated fluence patterns were generated using a simulated annealing optimization script, which attempts to achieve the image quality plan under a global dosimetric constraint. Optimization was repeated under different types of modulation constraints (e.g., fixed or gantry angle dependent patterns, continuous or comprised of discrete apertures) with the most limiting case being a fixed conventional bowtie filter. For each thoracic imaging task, an image quality map (IQM{sub sd}) representing the regionally varying standard deviation is predicted for each modulation method and compared to the prescribed image quality plan as well as against results from uniform fluence fields. Relative integral dose measures were also compared.Results: Each IQM{sub sd} resulting from FFMCT showed improved agreement with planned objectives compared to those from uniform fluence fields for all cases. Dynamically changing modulation patterns yielded better uniformity, improved image quality, and lower dose compared to fixed filter patterns with optimized tube current. For the latter fixed filter cases, the optimal choice of tube current modulation was found to depend heavily on the task. Average integral dose reduction compared

  2. Ammonia oxidation is not required for growth of Group 1.1c soil Thaumarchaeota

    PubMed Central

    Weber, Eva B.; Lehtovirta-Morley, Laura E.; Prosser, James I.; Gubry-Rangin, Cécile

    2015-01-01

    Thaumarchaeota are among the most abundant organisms on Earth and are ubiquitous. Within this phylum, all cultivated representatives of Group 1.1a and Group 1.1b Thaumarchaeota are ammonia oxidizers, and play a key role in the nitrogen cycle. While Group 1.1c is phylogenetically closely related to the ammonia-oxidizing Thaumarchaeota and is abundant in acidic forest soils, nothing is known about its physiology or ecosystem function. The goal of this study was to perform in situ physiological characterization of Group 1.1c Thaumarchaeota by determining conditions that favour their growth in soil. Several acidic grassland, birch and pine tree forest soils were sampled and those with the highest Group 1.1c 16S rRNA gene abundance were incubated in microcosms to determine optimal growth temperature, ammonia oxidation and growth on several organic compounds. Growth of Group 1.1c Thaumarchaeota, assessed by qPCR of Group 1.1c 16S rRNA genes, occurred in soil, optimally at 30°C, but was not associated with ammonia oxidation and the functional gene amoA could not be detected. Growth was also stimulated by addition of organic nitrogen compounds (glutamate and casamino acids) but not when supplemented with organic carbon alone. This is the first evidence for non-ammonia oxidation associated growth of Thaumarchaeota in soil. PMID:25764563

  3. Synthesis of [(11)C]MK-1064 as a new PET radioligand for imaging of orexin-2 receptor.

    PubMed

    Gao, Mingzhang; Wang, Min; Zheng, Qi-Huang

    2016-08-01

    The reference standard MK-1064 {5″-chloro-N-((5,6-dimethoxypyridin-2-yl)methyl)-[2,2':5',3″-terpyridine]-3'-carboxamide} was synthesized from methyl 2-chloro-5-iodonicotinate and 5-(chloropyridin-3-yl)boronic acid in 4 steps with 33% overall chemical yield. The precursor desmethyl-MK-1064 {5″-chloro-N-((5-hydroxy-6-methoxypyridin-2-yl)methyl)-[2,2':5',3″-terpyridine]-3'-carboxamide} for radiolabeling was synthesized from 2-bromopyridin-3-ol and 5″-chloro-[2,2':5',3″-terpyridine]-3'-carboxylic acid in 6 steps with 17% overall chemical yield. The target tracer [(11)C]MK-1064 {5″-chloro-N-((5-[(11)C]methoxy-6-methoxypyridin-2-yl)methyl)-[2,2':5',3″-terpyridine]-3'-carboxamide} was prepared by O-[(11)C]methylation of its corresponding precursor desmethyl-MK-1064 with [(11)C]CH3OTf under basic condition and isolated by a simplified solid-phase extraction (SPE) method in 50-60% decay corrected radiochemical yields based on [(11)C]CO2 at end of bombardment (EOB). The overall synthesis time from EOB was 23min, the radiochemical purity was >99%, and the specific activity at end of synthesis (EOS) was 185-555GBq/μmol. PMID:27268698

  4. Design and performance evaluation of single-use whole-sterile "plug & play" kits for routine automated production of [(11)C]choline and [(11)C]methionine with radiopharmaceutical quality.

    PubMed

    Quincoces, Gemma; López-Sánchez, Luisa; Sánchez-Martínez, María; Rodríguez-Fraile, Macarena; Peñuelas, Iván

    2010-12-01

    We herein describe the design and performance evaluation of single-use whole-sterile "plug & play" kits for routine automated production of [(11)C]methionine and [(11)C]choline for human use. Kits were designed for maximal simplicity and ease of using modules from Eckert & Ziegler Modular Lab System. The use of all-disposable sterile medical-grade material, helps ensure safety and cGMP compliance. The quick set-up and removal ("plug & play") also reduces radiation burden to operator. PMID:20685129

  5. Comparative analysis of SN1987A antineutrino fluence

    NASA Astrophysics Data System (ADS)

    Vissani, Francesco

    2015-01-01

    We discuss the electron antineutrino fluence derived from the events detected by Kamiokande-II, IMB and Baksan on 23 February 1987. The data are analysed adopting a new simple and accurate formula for the signal, improving on the previous modeling of the detectors response, considering the possibility of background events. We perform several alternative analyses to quantify the relevance of various descriptions, approximations and biases. In particular, we study the effect of: omitting Baksan data or neglecting the background, using simplified formulae for the signal, modifying the fluence to account for oscillations and pinching, including the measured times and angles of the events, using other descriptions of detector response, etc. We show that most of these effects are small or negligible and argue, by comparing the allowed regions for astrophysical parameters, that the results are stable. We comment on the accordance with theoretical results and on open questions.

  6. Accurate on line measurements of low fluences of charged particles

    NASA Astrophysics Data System (ADS)

    Palla, L.; Czelusniak, C.; Taccetti, F.; Carraresi, L.; Castelli, L.; Fedi, M. E.; Giuntini, L.; Maurenzig, P. R.; Sottili, L.; Taccetti, N.

    2015-03-01

    Ion beams supplied by the 3MV Tandem accelerator of LABEC laboratory (INFN-Firenze), have been used to study the feasibility of irradiating materials with ion fluences reproducible to about 1%. Test measurements have been made with 7.5 MeV 7Li2+ beams of different intensities. The fluence control is based on counting ions contained in short bursts generated by chopping the continuous beam with an electrostatic deflector followed by a couple of adjustable slits. Ions are counted by means of a micro-channel plate (MCP) detecting the electrons emitted from a thin layer of Al inserted along the beam path in between the pulse defining slits and the target. Calibration of the MCP electron detector is obtained by comparison with the response of a Si detector.

  7. In vivo kinetics and displacement study of a carbon-11-labeled hallucinogen, N,N-[11C]dimethyltryptamine.

    PubMed

    Yanai, K; Ido, T; Ishiwata, K; Hatazawa, J; Takahashi, T; Iwata, R; Matsuzawa, T

    1986-01-01

    The endogenous hallucinogen, N,N-dimethyltryptamine (DMT), was labeled with carbon-11 and its regional distribution in rat brain studied. [11C]DMT showed higher accumulation in the cerebral cortex, caudate putamen, and amygdaloid nuclei. Studies of the subcellular distribution of [11C]DMT revealed the specific localization in the fractions enriched with serotonin receptors only when a very low dose was injected into rats. The proportions of the radioactivity in receptor-rich fractions were greatly enhanced by pretreatment with the monoamine oxidase inhibitor, pargyline. Specific binding of [11C]DMT to serotonin receptors in dog brain was demonstrated by a positron emission tomographic study in which 5-methoxy-N,N-dimethyltryptamine caused approximately 20% displacement of the radioligand from the receptors. PMID:3489620

  8. Development of a NiO target for the production of 11C at ISAC/TRIUMF

    NASA Astrophysics Data System (ADS)

    Bricault, Pierre G.; Ames, Friedhelm; Dombsky, Marik; Kunz, Peter; Lassen, Jens; Mjøs, Anders; Wong, John

    2016-01-01

    High intensity 11C beams are necessary for the investigation of the formation of 12C via the nuclear reaction 11C(p, γ)12N → 12C + e+ + ν. The production of intense carbon beams on-line is quite challenging due to the thermodynamic properties and chemical reactivity of carbon at high temperatures. A previous attempt, using a medical isotope cyclotron production method in batch mode, was not conclusive. The intensity obtained was at least one order of magnitude too low for a direct proton capture experiment using the DRAGON facility at ISAC/TRIUMF. Producing a 11C beams using the ISOL method requires a target capable of efficiently releasing the carbon isotopes. NiO has been selected as a target material because most of the nickel carbides are not stable at high temperature. The development of carbon beams using a composite NiO/Ni target on-line is described.

  9. Fluence map optimization (FMO) with dose-volume constraints in IMRT using the geometric distance sorting method

    NASA Astrophysics Data System (ADS)

    Lan, Yihua; Li, Cunhua; Ren, Haozheng; Zhang, Yong; Min, Zhifang

    2012-10-01

    sorting method. By integrating a smart constraint adding/deleting scheme within the iteration framework, the new technique builds up an improved algorithm for solving the fluence map optimization with dose-volume constraints.

  10. Inertial confinement fusion method producing line source radiation fluence

    DOEpatents

    Rose, Ronald P.

    1984-01-01

    An inertial confinement fusion method in which target pellets are imploded in sequence by laser light beams or other energy beams at an implosion site which is variable between pellet implosions along a line. The effect of the variability in position of the implosion site along a line is to distribute the radiation fluence in surrounding reactor components as a line source of radiation would do, thereby permitting the utilization of cylindrical geometry in the design of the reactor and internal components.

  11. Fluence estimation by deconvolution via l1-norm minimization

    NASA Astrophysics Data System (ADS)

    García Hernández, J. C.; Lazaro-Ponthus, D.; Gmar, M.; Barthe, J.

    2011-03-01

    Advances in radiotherapy irradiation techniques have led to very complex treatments requiring for a more stringent control. The dosimetric properties of electronic portal imaging devices (EPID) encouraged their use for treatment verification. Two main approaches have been proposed: the forward approach, where measured portal dose images are compared to predicted dose images and the backward approach, where EPID images are used to estimate the dose delivered to the patient. Both approaches need EPID images to be converted into a fluence distribution by deconvolution. However, deconvolution is an ill-posed problem which is very sensitive to small variations on input data. This study presents the application of a deconvolution method based on l1-norm minimization; this is a method known for being very stable while working with noisy data. The algorithm was first evaluated on synthetic images with different noise levels, the results were satisfactory. Deconvolution algorithm was then applied to experimental portal images; the required EPID response kernel and energy fluence images were computed by Monte-Carlo calculation, accelerator treatment head and EPID models had already been commissioned in a previous work. The obtained fluence images were in good agreement with simulated fluence images. This deconvolution algorithm may be generalized to an inverse problem with a general operator, where image formation is not longer modeled by a convolution but by a linear operation that might be seen as a position-dependent convolution. Moreover, this procedure would be detector independent and could be used for any detector type provided its response function is known.

  12. Sensitivity Analysis and Neutron Fluence Adjustment for VVER-1000 Rpv

    NASA Astrophysics Data System (ADS)

    Belousov, S.; Ilieva, Kr.; Kirilova, D.

    2003-06-01

    Adjustment of the neutron fluence at the VVER-1000 RPV inner wall has been carried out. For the purpose of this adjustment the neutron flux response sensitivity to the main parameters of calculation uncertainty has been calculated. The obtained sensitivities, the parameters uncertainty and activity measurement data of iron, copper and niobium detectors positioned behind the RPV of Kozloduy NPP Unit 5 have been used in this adjustment.

  13. Evaluation of myocardial metabolism, with /sup 13/N- and /sup 11/C-labeled amino acids and positron computed tomography

    SciTech Connect

    Henze, E.; Schelbert, H.R.; Barrio, J.R.; Egbert, J.E.; Hansen, H.W.; MacDonald, N.S.; Phelps, M.E.

    1982-08-01

    To evaluate the utility of labeled L-amino acids (AA) for imaging regional myocardial AA metabolism by positron computed tomography (PCT), the myocardial uptake and clearance of Ala,* Glu, Gln, Asp, Leu tagged with /sup 13/N, and of /sup 11/C-tagged Asp, and oxaloacetate (Oxal), were examined in 44 experiments at control, during ischemia, and after transaminase inhibition. The myocardial time-activity curves recorded after intracoronary tracer injection had two clearance phases (an early and a late) for all /sup 13/N AA, and three (early, intermediate, late) for the two /sup 11/C compounds, with significantly different clearance half-times of 18.7 +/- 8.0 (s.d.) sec for the early phase, 141.7 +/- 56.5 sec for the intermediate, and 61.2 +/- 43.5 min for the late phase. The residual fractions ranged from 0.07 to 0.23 in normal myocardium, and consistently increased with ischemia by 0.01-0.07 for /sup 13/N-labeled Ala, Glu, Asp, and Leu, but not for /sup 13/N Gln and /sup 11/C compounds. Transaminase inhibition shortened the half-times of the late phases of /sup 13/N-labeled Ala, Glu, Asp, and Leu; had no effect on t1/2 of /sup 13/N Gln and /sup 11/C Oxal; and resulted in a loss of /sup 11/C CO/sub 2/ production and of the intermediate phase for /sup 11/C Asp. On the PCT images, /sup 13/N activity from labeled Ala and Glu was not decreased in an ischemic segment despite a significant flow reduction, as demonstrated by /sup 13/N NH/sub 3/ imaging and labeled microspheres. From the results, a three-compartment tracer kinetic model is proposed for the noninvasive quantification of Krebscycle activity, protein synthesis, and metabolic derangements related to ischemia.

  14. Blockade of [11C](+)-PHNO binding in human subjects by the dopamine D3 receptor antagonist ABT-925.

    PubMed

    Graff-Guerrero, Ariel; Redden, Laura; Abi-Saab, Walid; Katz, David A; Houle, Sylvain; Barsoum, Penny; Bhathena, Anahita; Palaparthy, Ramesh; Saltarelli, Mario D; Kapur, Shitij

    2010-04-01

    Dopamine D3 receptors are preferentially localized in the limbic system and midbrain, and thus may be involved in the pathophysiology of neuropsychiatry disorders. [11C](+)-PHNO is the first preferential D3 receptor radioligand in humans, yet there are no blockade studies with a D3 receptor antagonist in humans. This study characterized the blockade of [11C](+)-PHNO binding by ABT-925, a D3 receptor antagonist, in healthy male subjects. Sixteen subjects underwent 2-3 positron emission tomography (PET) scans, at baseline and following one or two doses of ABT-925 ranging from 50 mg to 600 mg. Receptor occupancies were estimated for globus pallidus, substantia nigra, caudate, putamen, and ventral striatum. At the 600-mg dose (n=9), ABT-925 receptor occupancy (mean+/-s.d.) was higher in substantia nigra (75+/-10%) and globus pallidus (64+/-22%) than in ventral striatum (44+/-17%), caudate (40+/-18%) and putamen (38+/-17%) (ANOVA: F4,140=15.02, p<0.001). The fractions of [11C](+)-PHNO binding attributable to D3 receptors in D3 receptor-rich regions were 100% (substantia nigra) and 90% (globus pallidus), and in D2 receptor-rich regions were 55% (caudate) and 53% (putamen). The ED50 of ABT-925 was 4.37 microg/ml across regions. Our results demonstrate that [11C](+)-PHNO binding can be blocked by a D3 receptor antagonist and confirm preclinical findings that [11C](+)-PHNO signal in the substantia nigra and globus pallidus is mainly reflective of its binding to D3 receptors. Thus, [11C](+)-PHNO seems a suitable PET radiotracer to estimate D3 receptor occupancy in humans. PMID:19751545

  15. Investigating expectation and reward in human opioid addiction with [11C]raclopride PET

    PubMed Central

    Watson, Ben J; Taylor, Lindsay G; Reid, Alastair G; Wilson, Sue J; Stokes, Paul R; Brooks, David J; Myers, James F; Turkheimer, Federico E; Nutt, David J; Lingford-Hughes, Anne R

    2014-01-01

    The rewarding properties of some abused drugs are thought to reside in their ability to increase striatal dopamine levels. Similar increases have been shown in response to expectation of a positive drug effect. The actions of opioid drugs on striatal dopamine release are less well characterized. We examined whether heroin and the expectation of heroin reward increases striatal dopamine levels in human opioid addiction. Ten opioid-dependent participants maintained on either methadone or buprenorphine underwent [11C]raclopride positron emission tomography imaging. Opioid-dependent participants were scanned three times, receiving reward from 50-mg intravenous heroin (diamorphine; pharmaceutical heroin) during the first scan to generate expectation of the same reward at the second scan, during which they only received 0.1-mg intravenous heroin. There was no heroin injection during the third scan. Intravenous 50-mg heroin during the first scan induced pronounced effects leading to high levels of expectation at the second scan. There was no detectable increase in striatal dopamine levels to either heroin reward or expectation of reward. We believe this is the first human study to examine whether expectation of heroin reward increases striatal dopamine levels in opioid addiction. The absence of detectable increased dopamine levels to both the expectation and delivery of a heroin-related reward may have been due to the impact of substitute medication. It does however contrast with the changes seen in abstinent stimulant users, suggesting that striatal dopamine release alone may not play such a pivotal role in opioid-maintained individuals. PMID:23829344

  16. BS69/ZMYND11 C-Terminal Domains Bind and Inhibit EBNA2

    PubMed Central

    Shen, Chih-Lung; Gonzalez-Hurtado, Elsie; Zhang, Zhi-Min; Xu, Muyu; Martinez, Ernest; Peng, Chih-Wen; Song, Jikui

    2016-01-01

    Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) plays an important role in driving immortalization of EBV-infected B cells through regulating the expression of many viral and cellular genes. We report a structural study of the tumor suppressor BS69/ZMYND11 C-terminal region, comprised of tandem coiled-coil-MYND domains (BS69CC-MYND), in complex with an EBNA2 peptide containing a PXLXP motif. The coiled-coil domain of BS69 self-associates to bring two separate MYND domains in close proximity, thereby enhancing the BS69 MYND-EBNA2 interaction. ITC analysis of BS69CC-MYND with a C-terminal fragment of EBNA2 further suggests that the BS69CC-MYND homodimer synergistically binds to the two EBNA2 PXLXP motifs that are respectively located in the conserved regions CR7 and CR8. Furthermore, we showed that EBNA2 interacts with BS69 and down-regulates its expression at both mRNA and protein levels in EBV-infected B cells. Ectopic BS69CC-MYND is recruited to viral target promoters through interactions with EBNA2, inhibits EBNA2-mediated transcription activation, and impairs proliferation of lymphoblastoid cell lines (LCLs). Substitution of critical residues in the MYND domain impairs the BS69-EBNA2 interaction and abolishes the BS69 inhibition of the EBNA2-mediated transactivation and LCL proliferation. This study identifies the BS69 C-terminal domains as an inhibitor of EBNA2, which may have important implications in development of novel therapeutic strategies against EBV infection. PMID:26845565

  17. Plasma based markers of [11C] PiB-PET brain amyloid burden.

    PubMed

    Kiddle, Steven John; Thambisetty, Madhav; Simmons, Andrew; Riddoch-Contreras, Joanna; Hye, Abdul; Westman, Eric; Pike, Ian; Ward, Malcolm; Johnston, Caroline; Lupton, Michelle Katharine; Lunnon, Katie; Soininen, Hilkka; Kloszewska, Iwona; Tsolaki, Magda; Vellas, Bruno; Mecocci, Patrizia; Lovestone, Simon; Newhouse, Stephen; Dobson, Richard

    2012-01-01

    Changes in brain amyloid burden have been shown to relate to Alzheimer's disease pathology, and are believed to precede the development of cognitive decline. There is thus a need for inexpensive and non-invasive screening methods that are able to accurately estimate brain amyloid burden as a marker of Alzheimer's disease. One potential method would involve using demographic information and measurements on plasma samples to establish biomarkers of brain amyloid burden; in this study data from the Alzheimer's Disease Neuroimaging Initiative was used to explore this possibility. Sixteen of the analytes on the Rules Based Medicine Human Discovery Multi-Analyte Profile 1.0 panel were found to associate with [(11)C]-PiB PET measurements. Some of these markers of brain amyloid burden were also found to associate with other AD related phenotypes. Thirteen of these markers of brain amyloid burden--c-peptide, fibrinogen, alpha-1-antitrypsin, pancreatic polypeptide, complement C3, vitronectin, cortisol, AXL receptor kinase, interleukin-3, interleukin-13, matrix metalloproteinase-9 total, apolipoprotein E and immunoglobulin E--were used along with co-variates in multiple linear regression, and were shown by cross-validation to explain >30% of the variance of brain amyloid burden. When a threshold was used to classify subjects as PiB positive, the regression model was found to predict actual PiB positive individuals with a sensitivity of 0.918 and a specificity of 0.545. The number of APOE [Symbol: see text] 4 alleles and plasma apolipoprotein E level were found to contribute most to this model, and the relationship between these variables and brain amyloid burden was explored. PMID:23028511

  18. Kinetics of 11C-labeled opiates in the brain of rhesus monkeys

    SciTech Connect

    Hartvig, P.; Bergstroem, K.; Lindberg, B.; Lundberg, P.O.; Lundqvist, H.; Langstroem, B.; Svaerd, H.; Rane, A.

    1984-07-01

    The regional uptake in the brain of Rhesus monkeys of i.v. administered 11C-labeled morphine, codeine, heroin and pethidine was studied by means of positron emission tomography. The technique measures the sum of parent drug and radiolabeled metabolites. (For the sake of simplicity the drug derived radioactivity is denoted by the drug name.) Morphine had a limited uptake to discrete areas of the brain. The maximum normalized uptake, with respect to dose per kilogram body weight, was about 0.2, i.e., 20% of the calculated activity if the drug had been evenly distributed throughout the body of the monkey. Maximum radioactivity appeared 30 to 45 min after injection. Morphine left the brain slowly with an estimated half-life of more than 2 hr. An area with a normalized uptake of about 1.0 was detected centrally in the lowest horizontal transsection of the skull. The origin of this area was identified as the pituitary. Codeine, heroin and pethidine were taken up to the brain to a larger extent than morphine, with maximum normalized uptakes of 2.6, 4.6 and 6.3, respectively. Maximum radioactivities of these drugs were achieved earlier and the elimination rates were faster than for morphine. Differences in the uptake of these drugs to the brain, as well as differences in time to maximal normalized uptake and rate of disappearance are considered to reflect differences in the lipophilic character between the drugs. Pethidine had the most rapid and extensive uptake followed by heroin, codeine and morphine in order of decreasing lipophilicity.

  19. Dopant distribution in high fluence Fe implanted GaN

    SciTech Connect

    Azarov, A. Yu.; Jensen, J.; Hallen, A.; Aggerstam, T.

    2008-09-01

    Undoped wurtzite GaN epilayers implanted at room temperature with 50-325 keV Fe{sup +} ions in the fluence range of 10{sup 15}-10{sup 17} ions/cm{sup 2} are studied by a combination of Rutherford backscattering/channeling spectrometry and time-of-flight elastic recoil detection analysis. The results show an enhanced Fe concentration close to the surface for high ion fluences (>1x10{sup 16} cm{sup -2}), which increases with the ion fluence. Annealing at 800 deg. C for 30 min has a negligible effect on the Fe distribution in the material bulk, but further increases the Fe concentration near the surface. Our findings can be understood by radiation enhanced diffusion during ion implantation and an increased Fe diffusivity in the near surface region with distorted stoichiometry, or formation of secondary phases and precipitates for the highest doses. The simulation shows that, if enhanced diffusion is the reason for Fe buildup at the surface, both radiation enhanced diffusion and the thermal diffusion of Fe atoms near the surface, need to be at least five times larger than ordinary bulk diffusion to explain the increased Fe surface concentration.

  20. Temperature Dependence of the Flare Fluence Scaling Exponent

    NASA Astrophysics Data System (ADS)

    Kretzschmar, M.

    2015-12-01

    Solar flares result in an increase of the solar irradiance at all wavelengths. While the distribution of the flare fluence observed in coronal emission has been widely studied and found to scale as f(E)˜ E^{-α}, with α slightly below 2, the distribution of the flare fluence in chromospheric lines is poorly known. We used the solar irradiance measurements observed by the SDO/EVE instrument at a 10 s cadence to investigate the dependency of the scaling exponent on the formation region of the lines (or temperature). We analyzed all flares above the C1 level since the start of the EVE observations (May 2010) to determine the flare fluence distribution in 16 lines covering a wide range of temperatures, several of which were not studied before. Our results show a weak downward trend with temperature of the scaling exponent of the PDF that reaches from above 2 at lower temperature (a few 104 K) to {˜ }1.8 for hot coronal emission (several 106 K). However, because colder lines also have fainter contrast, we cannot exclude that this behavior is caused by including more noise for smaller flares for these lines. We discuss the method and its limitations and tentatively associate this possible trend with the different mechanisms responsible for the heating of the chromosphere and corona during flares.

  1. Correlating Fast Fluence to dpa in Atypical Locations

    NASA Astrophysics Data System (ADS)

    Drury, Thomas H.

    2016-02-01

    Damage to a nuclear reactor's materials by high-energy neutrons causes changes in the ductility and fracture toughness of the materials. The reactor vessel and its associated piping's ability to withstand stress without brittle fracture are paramount to safety. Theoretically, the material damage is directly related to the displacements per atom (dpa) via the residual defects from induced displacements. However in practice, the material damage is based on a correlation to the high-energy (E > 1.0 MeV) neutron fluence. While the correlated approach is applicable when the material in question has experienced the same neutron spectrum as test specimens which were the basis of the correlation, this approach is not generically acceptable. Using Monte Carlo and discrete ordinates transport codes, the energy dependent neutron flux is determined throughout the reactor structures and the reactor vessel. Results from the models provide the dpa response in addition to the high-energy neutron flux. Ratios of dpa to fast fluence are calculated throughout the models. The comparisons show a constant ratio in the areas of historical concern and thus the validity of the correlated approach to these areas. In regions above and below the fuel however, the flux spectrum has changed significantly. The correlated relationship of material damage to fluence is not valid in these regions without adjustment. An adjustment mechanism is proposed.

  2. Comparison of build-up region doses in oblique tangential 6 MV photon beams calculated by AAA and CCC algorithms in breast Rando phantom

    NASA Astrophysics Data System (ADS)

    Masunun, P.; Tangboonduangjit, P.; Dumrongkijudom, N.

    2016-03-01

    The purpose of this study is to compare the build-up region doses on breast Rando phantom surface with the bolus covered, the doses in breast Rando phantom and also the doses in a lung that is the heterogeneous region by two algorithms. The AAA in Eclipse TPS and the collapsed cone convolution algorithm in Pinnacle treatment planning system were used to plan in tangential field technique with 6 MV photon beam at 200 cGy total doses in Breast Rando phantom with bolus covered (5 mm and 10 mm). TLDs were calibrated with Cobalt-60 and used to measure the doses in irradiation process. The results in treatment planning show that the doses in build-up region and the doses in breast phantom were closely matched in both algorithms which are less than 2% differences. However, overestimate of doses in a lung (L2) were found in AAA with 13.78% and 6.06% differences at 5 mm and 10 mm bolus thickness, respectively when compared with CCC algorithm. The TLD measurements show the underestimate in buildup region and in breast phantom but the doses in a lung (L2) were overestimated when compared with the doses in the two plannings at both thicknesses of the bolus.

  3. Influence of light-curing protocols on polymerization shrinkage and shrinkage force of a dual-cured core build-up resin composite.

    PubMed

    Tauböck, Tobias T; Bortolotto, Tissiana; Buchalla, Wolfgang; Attin, Thomas; Krejci, Ivo

    2010-08-01

    This study investigated the influence of time delay and duration of photo-activation on linear polymerization shrinkage, shrinkage force, and hardening of a dual-cured core build-up resin composite. The test material (Rebilda DC) was light-cured for 20 or 60 s either early (2 min) or late (7 min) after the start of mixing. Non-irradiated self-cured specimens served as controls. Linear shrinkage and shrinkage force were measured for 60 min using custom-made devices. Knoop hardness was determined at the end of the observation period. Self-cured controls, showing a linear shrinkage similar to that of specimens early light-cured for 20 s generated the lowest shrinkage force and hardness. A shorter light exposure time (20 s vs. 60 s) reduced linear shrinkage, shrinkage force, and hardness when early light-curing was performed, but did not affect the three properties in specimens light-cured late after the start of mixing. Late photo-activation increased linear shrinkage, irrespective of irradiation time, and resulted in a higher shrinkage force and hardness for short light exposure time. A moderate correlation was found between the two shrinkage properties studied (r(2) = 0.65). In conclusion, improvements in shrinkage behavior of the tested core build-up material were associated with inferior hardening, making it important to adapt curing protocols to the clinical situation. PMID:20662918

  4. Capacity building on systems engineering, management and projects control for the nanosatc-br cubesat development program - library & data-bank building up

    NASA Astrophysics Data System (ADS)

    Farias, Tiago Travi; Schuch, Nelson Jorge; Lourencena Caldas Franke, Lucas; Moro, Pietro Fernando; Ramos Manica, Thales; Cupertino Durao, Otavio S.; Jaenisch, Guilherme Paul; Escobar B, Eduardo; Zavareze da Costa, Leonardo; Balestrin, Maurício Ricardo; Camargo Silveira, Iago; Francisco Mozzaquatro Wen, João

    The Capacity Building (CB) on Systems Engineering, Management && Projects Control for the Brazilian NANOSATC-BR Cubesat Development Program - library && data-bank building up results are presented. The Program && its CB involves a partnership between the INPE's Southern Regional Space Research - CRS/INPE - MCTI and the Federal University of Santa Maria - UFSM, through the Santa Maria Space Science Laboratory LACESM/CT - UFSM. The NANOSATC-BR Program consists of two nanosatellites, the NANOSATC-BR1, a 1U standard CubeSat, that is predicted to be launched in the first semester of 2014 (the first Brazilian CubeSat which will be launched) and the NANOSATC-BR2 - 2U CubeSat, which is expected to be launched in the first semester of 2015. The main goal of this paper is to introduce the application of Systems Engineering, Management && Projects Control documentation methodologies in the library building up and data-bank procedures for the CB, Program and its Projects: NANOSATC-BR 1 && 2. These CB, Program and Projects have support from the Brazilian Space Agency (AEB).

  5. Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams.

    PubMed

    Kim, K-A; Yoo, W J; Jang, K W; Moon, J; Han, K-T; Jeon, D; Park, J-Y; Cha, E-J; Lee, B

    2013-03-01

    In this study, a fibre-optic dosemeter (FOD) using an organic scintillator with a diameter of 0.5 mm for photon-beam therapy dosimetry was fabricated. The fabricated dosemeter has many advantages, including water equivalence, high spatial resolution, remote sensing and real-time measurement. The scintillating light generated from an organic-dosemeter probe embedded in a solid-water stack phantom is guided to a photomultiplier tube and an electrometer via 20 m of plastic optical fibre. Using this FOD, the skin dose and the percentage depth dose in the build-up region according to the depths of a solid-water stack phantom are measured with 6- and 15-MV photon-beam energies with field sizes of 10 × 10 and 20 × 20 cm(2), respectively. The results are compared with those measured using conventional dosimetry films. It is expected that the proposed FOD can be effectively used in radiotherapy dosimetry for accurate measurement of the skin dose and the depth dose distribution in the build-up region due to its high spatial resolution. PMID:22764176

  6. 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

  7. Distinct cerebral lesions in sporadic and 'D90A' SOD1 ALS: studies with [11C]flumazenil PET.

    PubMed

    Turner, M R; Hammers, A; Al-Chalabi, A; Shaw, C E; Andersen, P M; Brooks, D J; Leigh, P N

    2005-06-01

    Five to ten percent of amyotrophic lateral sclerosis (ALS) cases are associated with mutations of the superoxide dismutase-1 (SOD1) gene, and the 'D90A' mutation is associated with a unique phenotype and markedly slower disease progression (mean survival time 14 years). Relative sparing of inhibitory cortical neuronal circuits might be one mechanism contributing to the slower progression in patients homozygous for the D90A mutation (homD90A). The GABA(A) receptor PET ligand [11C]flumazenil has demonstrated motor and extra-motor cortical changes in sporadic ALS. In this study, we used [11C]flumazenil PET to explore differences in the pattern of cortical involvement between sporadic and genetically homogeneous ALS groups. Twenty-four sporadic ALS (sALS) and 10 homD90A patients underwent [11C]flumazenil PET of the brain. In addition, two subjects homozygous for the D90A mutation, but without symptoms or signs ('pre-symptomatic', psD90A), also underwent imaging. Results for each group were compared with those for 24 healthy controls of similar age. Decreases in the binding of [11C]flumazenil in the sALS group were found within premotor regions, motor cortex and posterior motor association areas. In the homD90A group of ALS patients, however, decreases were concentrated in the left fronto-temporal junction and anterior cingulate gyrus. In the two psD90A subjects, a small focus of reduced [11C]flumazenil binding at the left fronto-temporal junction was seen, similar to the pattern seen in the clinically affected patients. Within the sALS group, there was no statistically significant association between decreases in cortical [11C]flumazenil binding and revised ALS functional rating scale (ALSFRS-R score), whereas the upper motor neuron (UMN) score correlated with widespread and marked cortical decreases over the dominant hemisphere. In the homD90A group, there was a stronger statistical association between reduced cortical [11C]flumazenil binding and the ALSFRS-R, rather

  8. Imaging of Carrageenan-Induced Local Inflammation and Adjuvant-Induced Systemic Arthritis with [11C]PBR28 PET

    PubMed Central

    Shao, Xia; Wang, Xueding; English, Sean J; Desmond, Timothy; Sherman, Phillip S; Quesada, Carole A; Piert, Morand R

    2013-01-01

    Introduction [11C]PBR28 binding to translocator protein (TSPO) was evaluated for imaging of acute and chronic inflammation using two established rat models. Methods Acute inflammation was induced by local Carrageenan-injection into the paw of Fisher 344 rats (model A). T-cell mediated adjuvant arthritis was induced by heat-inactivated Mycobacterium butyricum injection in Lewis rats (model B). Micro-PET scan was performed after injection of approximately 35 MBq [11C]PBR28. In model A, volumes of interest (VOIs) were defined in the paw of Fisher 344 rats (n=6) with contralateral sham treatment as control. For model B, VOIs were defined in the tail, sacroiliac joints, hips, knees and thigh muscles of M. butyricum treated animals (n=8) and compared with sham-treated controls (n=4). The peak 11C-PBR28 SUV (SUVpeak) and area under the curve (AUCSUV) of 60-minute time-activity data were calculated. Immunohistochemistry for CD68, a macrophage stain, was performed from paw tissues. In addition, the [11C]PBR28 cell uptake was measured in lipopolysaccharide (LPS)-stimulated and non-stimulated macrophage cultures. Results LPS-stimulated macrophages displayed dose-dependent increased [11C]PBR28 uptake, which was blocked by non-labeled PBR28. In both models, radiotracer uptake of treated lesions increased rapidly within minutes and displayed overall accumulative kinetics. The SUVpeak and AUCSUV of Carrageenan-treated paws was significantly increased compared to controls. Also, the [11C]PBR28 uptake ratio of Carrageenan-treated vs. sham-treated paw correlated significantly with CD68 staining ratios of the same animals. In adjuvant arthritis, significantly increased [11C]PBR28 SUVpeak and AUCSUV values were identified at the tail, knees, and sacroiliac joints, while no significant differences were identified in the lumbar spine and hips. Conclusions Based on our initial data, [11C]PBR28 PET appears to have potential for imaging of various inflammatory processes involving

  9. Kinetics of (/sup 11/C)N,N-dimethylphenylethylamine in mice and humans: potential for measurement of brain MAO-B activity

    SciTech Connect

    Shinotoh, H.; Inoue, O.; Suzuki, K.; Yamasaki, T.; Iyo, M.; Hashimoto, K.; Tominaga, T.; Itoh, T.; Tateno, Y.; Ikehira, H.

    1987-06-01

    Carbon-11-labeled N,N-dimethylphenylethylamine ((/sup 11/C)DMPEA) was synthesized by the reaction of N-methylphenylethylamine with (/sup 11/C)methyl iodide. This newly synthesized radiotracer was developed for the purpose of in vivo measurement of monoamine oxidase-B activity in the brain using a metabolic trapping method. Initially, biodistribution was investigated in mice. The rapid and high uptake of /sup 11/C radioactivity in the brain was observed following intravenous injection of (/sup 11/C)DMPEA, the peak of which was reached at 1 min, followed by a decrease at 1-5 min and slowly thereafter. The kinetics of (/sup 11/C)DMPEA in the human brain were determined using positron emission tomography (PET) and showed that /sup 11/C radioactivity increased gradually over 60 min following initial rapid uptake of /sup 11/C radioactivity, with basal ganglia and thalamus showing high accumulation.

  10. IL-3 and CSF-1 Interact to Promote Generation of CD11c+ IL-10-Producing Macrophages

    PubMed Central

    Sheng, Kuo-Ching; Herrero, Lara J.; Taylor, Adam; Hapel, Andrew J.; Mahalingam, Suresh

    2014-01-01

    Unraveling the mechanisms of hematopoiesis regulated by multiple cytokines remains a challenge in hematology. IL-3 is an allergic cytokine with the multilineage potential, while CSF-1 is produced in the steady state with restricted lineage coverage. Here, we uncovered an instructive role of CSF-1 in IL-3-mediated hematopoiesis. CSF-1 significantly promoted IL-3-driven CD11c+ cell expansion and dampened basophil and mast cell generation from C57BL/6 bone marrow. Further studies indicated that the CSF-1/CSF-1R axis contributed significantly to IL-3-induced CD11c+ cell generation through enhancing c-Fos-associated monopoiesis. CD11c+ cells induced by IL-3 or IL-3/CSF-1 were competent in cellular maturation and endocytosis. Both IL-3 and IL-3/CSF-1 cells lacked classical dendritic cell appearance and resembled macrophages in morphology. Both populations produced a high level of IL-10, in addition to IL-1, IL-6 and TNFα, in response to LPS, and were relatively poor T cell stimulators. Collectively, these findings reveal a role for CSF-1 in mediating the IL-3 hematopoietic pathway through monopoiesis, which regulates expansion of CD11c+ macrophages. PMID:24743235

  11. Search for new resonant states in 10C and 11C and their impact on the cosmological lithium problem

    NASA Astrophysics Data System (ADS)

    Hammache, F.; Coc, A.; de Séréville, N.; Stefan, I.; Roussel, P.; Ancelin, S.; Assié, M.; Audouin, L.; Beaumel, D.; Franchoo, S.; Fernandez-Dominguez, B.; Fox, S.; Hamadache, C.; Kiener, J.; Laird, A.; Le Crom, B.; Lefebvre-Schuhl, A.; Lefebvre, L.; Matea, I.; Matta, A.; Mavilla, G.; Mrazek, J.; Morfouace, P.; de Oliveira Santos, F.; Parikh, A.; Perrot, L.; Sanchez-Benitez, A. M.; Suzuki, D.; Tatischeff, V.; Ujic, P.; Vandebrouck, M.

    2013-12-01

    The observed primordial 7Li abundance in metal-poor halo stars is found to be lower than its Big-Bang nucleosynthesis (BBN) calculated value by a factor of approximately three. Some recent works suggested the possibility that this discrepancy originates from missing resonant reactions which would destroy 7Be, parent of 7Li. The most promising candidate resonances which were found include a possibly missed 1- or 2- narrow state around 15 MeV in the compound nucleus 10C formed by 7Be+3He and a state close to 7.8 MeV in the compound nucleus 11C formed by 7Be+4He. In this work, we studied the high excitation energy region of 10C and the low excitation energy region in 11C via the reactions 10B(3He,t)10C and 11B(3He,t)11C, respectively, at the incident energy of 35 MeV. Our results for 10C do not support 7Be+3He as a possible solution for the 7Li problem. Concerning 11C results, the data show no new resonances in the excitation energy region of interest and this excludes the 7Be+4He reaction channel as an explanation for the 7Li deficit.

  12. Design of Infusion Schemes for Neuroreceptor Imaging: Application to [11C]Flumazenil-PET Steady-State Study

    PubMed Central

    Feng, Ling; Svarer, Claus; Madsen, Karine; Ziebell, Morten; Dyssegaard, Agnete; Ettrup, Anders; Hansen, Hanne Demant; Lehel, Szabolcs; Yndgaard, Stig; Paulson, Olaf Bjarne; Knudsen, Gitte Moos; Pinborg, Lars Hageman

    2016-01-01

    This study aims at developing a simulation system that predicts the optimal study design for attaining tracer steady-state conditions in brain and blood rapidly. Tracer kinetics was determined from bolus studies and used to construct the system. Subsequently, the system was used to design inputs for bolus infusion (BI) or programmed infusion (PI) experiments. Steady-state quantitative measurements can be made with one short scan and venous blood samples. The GABAA receptor ligand [11C]Flumazenil (FMZ) was chosen for this purpose, as it lacks a suitable reference region. Methods. Five bolus [11C]FMZ-PET scans were conducted, based on which population-based PI and BI schemes were designed and tested in five additional healthy subjects. The design of a PI was assisted by an offline feedback controller. Results. The system could reproduce the measurements in blood and brain. With PI, [11C]FMZ steady state was attained within 40 min, which was 8 min earlier than the optimal BI (B/I ratio = 55 min). Conclusions. The system can design both BI and PI schemes to attain steady state rapidly. For example, subjects can be [11C]FMZ-PET scanned after 40 min of tracer infusion for 40 min with venous sampling and a straight-forward quantification. This simulation toolbox is available for other PET-tracers. PMID:27123457

  13. Production of pure quasi-monochromatic 11C beams for accurate radiation therapy and dose delivery verification

    NASA Astrophysics Data System (ADS)

    Lazzeroni, Marta; Brahme, Anders

    2015-09-01

    In the present study we develop a new technique for the production of clean quasi-monochromatic 11C positron emitter beams for accurate radiation therapy and PET-CT dose delivery imaging and treatment verification. The 11C ion beam is produced by projectile fragmentation using a primary 12C ion beam. The practical elimination of the energy spread of the secondary 11C fragments and other beam contaminating fragments is described. Monte Carlo calculation with the SHIELD-HIT10+ code and analytical methods for the transport of the ions in matter are used in the analysis. Production yields, as well as energy, velocity and magnetic rigidity distributions of the fragments generated in a cylindrical target are scored as a function of the depth within 1 cm thick slices for an optimal target consisting of a fixed 20 cm section of liquid hydrogen followed by a variable thickness section of polyethylene. The wide energy and magnetic rigidity spread of the 11C ion beam can be reduced to values around 1% by using a variable monochromatizing wedge-shaped degrader in the beam line. Finally, magnetic rigidity and particle species selection, as well as discrimination of the particle velocity through a combined Time of Flight and Radio Frequency-driven Velocity filter purify the beam from similar magnetic rigidity contaminating fragments (mainly 7Be and 3He fragments). A beam purity of about 99% is expected by the combined method.

  14. Multi-Scale hierarchical generation of PET parametric maps: application and testing on a [11C]DPN study.

    PubMed

    Rizzo, G; Turkheimer, F E; Keihaninejad, S; Bose, S K; Hammers, A; Bertoldo, A

    2012-02-01

    We propose a general approach to generate parametric maps. It consists in a multi-stage hierarchical scheme where, starting from the kinetic analysis of the whole brain, we then cascade the kinetic information to anatomical systems that are akin in terms of receptor densities, and then down to the voxel level. A-priori classes of voxels are generated either by anatomical atlas segmentation or by functional segmentation using unsupervised clustering. Kinetic properties are transmitted to the voxels in each class using maximum a posteriori (MAP) estimation method. We validate the novel method on a [11C]diprenorphine (DPN) test-retest data-set that represents a challenge to estimation given [11C]DPN's slow equilibration in tissue. The estimated parametric maps of volume of distribution (VT) reflect the opioid receptor distributions known from previous [11C]DPN studies. When priors are derived from the anatomical atlas, there is an excellent agreement and strong correlation among voxel MAP and ROI results and excellent test-retest reliability for all subjects but one. Voxel level results did not change when priors were defined through unsupervised clustering. This new method is fast (i.e. 15 min per subject) and applied to [11C]DPN data achieves accurate quantification of VT as well as high quality VT images. Moreover, the way the priors are defined (i.e. using an anatomical atlas or unsupervised clustering) does not affect the estimates. PMID:21924366

  15. 17 CFR 274.11c - Form N-4, registration statement of separate accounts organized as unit investment trusts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... chapter). Editorial Note: For Federal Register citations affecting Form N-4, see the List of CFR Sections... COMPANY ACT OF 1940 Registration Statements § 274.11c Form N-4, registration statement of separate... filed pursuant to section 8(b) of the Investment Company Act of 1940 by separate accounts that...

  16. The 11C Project:Measurement of Root Exudation at Elevated CO2 Levels in Low and High Nutrient Solutions

    NASA Astrophysics Data System (ADS)

    Leandre, Verida; Howell, Calvin

    2011-03-01

    Understanding the plant kingdom's mechanisms of resource management in variable environments is integral to predicting how plants will respond to an increase in atmospheric CO2 . The goal of this study is to determine the effects of changing nutrient conditions on the root exudation of barley plants at elevated CO2 levels. The 11 C group at the Triangle Universities Nuclear Laboratory (TUNL) tags various species of plants with short-lived positron-emitting radioisotopes in order to analyze metabolite transport in response to changes in the environment. 11 C is produced at TUNL using a tandem Van de Graaff particle accelerator, then transported from TUNL to the Duke Univ. Phytotron (100m) where plants are labeled with 11 C in a growth chamber. The chamber allows researchers to control the light intensity, air temperature, humidity and concentration of CO2 in the air. The plant absorbs 11 CO2 in a leaf that is placed inside a cuvette through which radioactive 11 CO2 gas flows. The sugars in the labeling leaf are tagged with 11 C and translocated throughout the plant similar to 12 C. Scintillation detectors are used to track the tagged sugars as they are translocated through the plant and exudated from the root into the nutrient solution or 11 CO2 gas is respired by the root. The labeling system, detector arrangement, electronics and data analysis will be described and preliminary results will be presented.

  17. Determination of Fatty Acid Metabolism with Dynamic 11C-Palmitate Positron Emission Tomography of Mouse Heart In Vivo

    PubMed Central

    Li, Yinlin; Huang, Tao; Zhang, Xinyue; Zhong, Min; Walker, Natalie N.; He, Jiang; Berr, Stuart S.; Keller, Susanna R.; Kundu, Bijoy K.

    2015-01-01

    The goal of this study was to establish a quantitative method for measuring FA metabolism with partial volume (PV) and spill-over (SP) corrections using dynamic 11C-palmitate PET images of mouse heart in vivo. Methods Twenty-minute dynamic 11C-palmitate PET scans of four 18–20 week old male C57BL/6 mice under isoflurane anesthesia were performed using a Focus 120 PET scanner. A model corrected blood input function (MCIF), by which the input function with SP and PV corrections and the metabolic rate constants (k1−k5) are simultaneously estimated from the dynamic 11C-palmitate PET images of mouse hearts in a 4-compartment tracer kinetic model, was used to determine rates of myocardial FA oxidation (MFAO), myocardial FA esterification (MFAE), myocardial FA utilization (MFAU) and myocardial FA uptake (MFAUp). Results The MFAO thus measured in C57BL/6 mice was 375.03±43.83 nmoles/min/g. This compares well with the MFAO measured in perfused working C57BL/6 mouse hearts ex vivo of about 350 nmoles/g/min and 400 nmoles/min/g. Conclusions FA metabolism was measured for the first time in mouse heart in vivo using dynamic 11C-palmitate PET in a 4-compartment tracer kinetic model. MFAO obtained with this model were validated by results previously obtained with mouse hearts ex vivo. PMID:26462138

  18. Experimental Approach to Evaluate the 11C Perfusion and Diffusion in Small Animal Tissues for HadronPET Applications

    PubMed Central

    Martínez-Rovira, Immaculada; Boisgard, Raphaël; Pottier, Géraldine; Kuhnast, Bertrand; Jan, Sébastien

    2016-01-01

    The development of a reliable dose monitoring system in hadron therapy is essential in order to control the treatment plan delivery. Positron Emission Tomography (PET) is the only method used in clinics nowadays for quality assurance. However, the accuracy of this method is limited by the loss of signal due to the biological washout processes. Up to the moment, very few studies measured the washout processes and there is no database of washout data as a function of the tissue and radioisotope. One of the main difficulties is related to the complexity of such measurements, along with the limited time slots available in hadron therapy facilities. Thus, in this work, we proposed an alternative in vivo methodology for the measurement and modeling of the biological washout parameters without any radiative devices. It consists in the implementation of a point-like radioisotope source by direct injection on the tissues of interest and its measurement by means of high-resolution preclinical PET systems. In particular, the washout of 11C carbonate radioisotopes was assessed, considering that 11C is is the most abundant β+ emitter produced by carbon beams. 11C washout measurements were performed in several tissues of interest (brain, muscle and 9L tumor xenograf) in rodents (Wistar rat). Results show that the methodology presented is sensitive to the washout variations depending on the selected tissue. Finally, a first qualitative correlation between 11C tumor washout properties and tumor metabolism (via 18F-FDG tracer uptake) was found. PMID:27015269

  19. Design of Infusion Schemes for Neuroreceptor Imaging: Application to [(11)C]Flumazenil-PET Steady-State Study.

    PubMed

    Feng, Ling; Svarer, Claus; Madsen, Karine; Ziebell, Morten; Dyssegaard, Agnete; Ettrup, Anders; Hansen, Hanne Demant; Lehel, Szabolcs; Yndgaard, Stig; Paulson, Olaf Bjarne; Knudsen, Gitte Moos; Pinborg, Lars Hageman

    2016-01-01

    This study aims at developing a simulation system that predicts the optimal study design for attaining tracer steady-state conditions in brain and blood rapidly. Tracer kinetics was determined from bolus studies and used to construct the system. Subsequently, the system was used to design inputs for bolus infusion (BI) or programmed infusion (PI) experiments. Steady-state quantitative measurements can be made with one short scan and venous blood samples. The GABAA receptor ligand [(11)C]Flumazenil (FMZ) was chosen for this purpose, as it lacks a suitable reference region. Methods. Five bolus [(11)C]FMZ-PET scans were conducted, based on which population-based PI and BI schemes were designed and tested in five additional healthy subjects. The design of a PI was assisted by an offline feedback controller. Results. The system could reproduce the measurements in blood and brain. With PI, [(11)C]FMZ steady state was attained within 40 min, which was 8 min earlier than the optimal BI (B/I ratio = 55 min). Conclusions. The system can design both BI and PI schemes to attain steady state rapidly. For example, subjects can be [(11)C]FMZ-PET scanned after 40 min of tracer infusion for 40 min with venous sampling and a straight-forward quantification. This simulation toolbox is available for other PET-tracers. PMID:27123457

  20. Experimental Approach to Evaluate the 11C Perfusion and Diffusion in Small Animal Tissues for HadronPET Applications.

    PubMed

    Martínez-Rovira, Immaculada; Boisgard, Raphaël; Pottier, Géraldine; Kuhnast, Bertrand; Jan, Sébastien

    2016-01-01

    The development of a reliable dose monitoring system in hadron therapy is essential in order to control the treatment plan delivery. Positron Emission Tomography (PET) is the only method used in clinics nowadays for quality assurance. However, the accuracy of this method is limited by the loss of signal due to the biological washout processes. Up to the moment, very few studies measured the washout processes and there is no database of washout data as a function of the tissue and radioisotope. One of the main difficulties is related to the complexity of such measurements, along with the limited time slots available in hadron therapy facilities. Thus, in this work, we proposed an alternative in vivo methodology for the measurement and modeling of the biological washout parameters without any radiative devices. It consists in the implementation of a point-like radioisotope source by direct injection on the tissues of interest and its measurement by means of high-resolution preclinical PET systems. In particular, the washout of 11C carbonate radioisotopes was assessed, considering that 11C is is the most abundant β+ emitter produced by carbon beams. 11C washout measurements were performed in several tissues of interest (brain, muscle and 9L tumor xenograf) in rodents (Wistar rat). Results show that the methodology presented is sensitive to the washout variations depending on the selected tissue. Finally, a first qualitative correlation between 11C tumor washout properties and tumor metabolism (via 18F-FDG tracer uptake) was found. PMID:27015269

  1. General last-step labeling of biomolecule-based substrates by [12C], [13C], and [11C] carbon monoxide.

    PubMed

    Cornilleau, Thomas; Audrain, Hélène; Guillemet, Aude; Hermange, Philippe; Fouquet, Eric

    2015-01-16

    Alkaloid-, steroid-, biotin-, carbohydrate-, nucleoside-, and peptide-based bioconjugates are easily labeled with CO by a last-step palladium-catalyzed carbonylation. The choice of the [(12)C], [(13)C], or [(11)C] isotope opens the way to a new class of potential tracers or ligands easily available for various applications. PMID:25562588

  2. Impact of [{sup 11}C]Methionine Positron Emission Tomography for Target Definition of Glioblastoma Multiforme in Radiation Therapy Planning

    SciTech Connect

    Matsuo, Masayuki; Miwa, Kazuhiro; Tanaka, Osamu; Shinoda, Jun; Nishibori, Hironori; Tsuge, Yusuke; Yano, Hirohito; Iwama, Toru; Hayashi, Shinya; Hoshi, Hiroaki; Yamada, Jitsuhiro; Kanematsu, Masayuki; Aoyama, Hidefumi

    2012-01-01

    Purpose: The purpose of this work was to define the optimal margins for gadolinium-enhanced T{sub 1}-weighted magnetic resonance imaging (Gd-MRI) and T{sub 2}-weighted MRI (T{sub 2}-MRI) for delineating target volumes in planning radiation therapy for postoperative patients with newly diagnosed glioblastoma multiforme (GBM) by comparison to carbon-11-labeled methionine positron emission tomography ([{sup 11}C]MET-PET) findings. Methods and Materials: Computed tomography (CT), MRI, and [{sup 11}C]MET-PET were separately performed for radiation therapy planning for 32 patients newly diagnosed with GBM within 2 weeks after undergoing surgery. The extent of Gd-MRI (Gd-enhanced clinical target volume [CTV-Gd]) uptake and that of T{sub 2}-MRI of the CTV (CTV-T{sub 2}) were compared with the extent of [{sup 11}C]MET-PET (CTV--[{sup 11}C]MET-PET) uptake by using CT--MRI or CT--[{sup 11}C]MET-PET fusion imaging. We defined CTV-Gd (x mm) and CTV-T{sub 2} (x mm) as the x-mm margins (where x = 0, 2, 5, 10, and 20 mm) outside the CTV-Gd and the CTV-T{sub 2}, respectively. We evaluated the relationship between CTV-Gd (x mm) and CTV-- [{sup 11}C]MET-PET and the relationship between CTV-T{sub 2} (x mm) and CTV-- [{sup 11}C]MET-PET. Results: The sensitivity of CTV-Gd (20 mm) (86.4%) was significantly higher than that of the other CTV-Gd. The sensitivity of CTV-T{sub 2} (20 mm) (96.4%) was significantly higher than that of the other CTV-T{sub 2} (x = 0, 2, 5, 10 mm). The highest sensitivity and lowest specificity was found with CTV-T{sub 2} (x = 20 mm). Conclusions: It is necessary to use a margin of at least 2 cm for CTV-T{sub 2} for the initial target planning of radiation therapy. However, there is a limit to this setting in defining the optimal margin for Gd-MRI and T{sub 2}-MRI for the precise delineation of target volumes in radiation therapy planning for postoperative patients with GBM.

  3. Synthesis and preliminary evaluation of (S)-[11C]-exaprolol, a novel beta-adrenoceptor ligand for PET.

    PubMed

    van Waarde, Aren; Doorduin, Janine; de Jong, Johan R; Dierckx, Rudi A; Elsinga, Philip H

    2008-01-01

    Positron-emitting beta-adrenoceptor ligands for the CNS could allow determination of changes in beta-adrenoceptor availability after treatment of patients with norepinephrine reuptake inhibitors or tricyclic antidepressants, and differential diagnosis between multiple sclerosis and other brain disorders in an early stage of the disease. No ligands suitable for this purpose are available for human use. In order to prepare a tracer for human studies, we labeled the biologically active enantiomer of the beta-blocker exaprolol with (11)C. Exaprolol has the appropriate lipophilicity (log P + 1.6) for entry of the CNS and is claimed to be a very potent beta-adrenoceptor antagonist. (S)-Desisopropyl-exaprolol was synthesized by reaction of 2-hexylphenol with (S)-glycidyl-nosylate followed by ring opening using ammonia gas. The desisopropyl precursor was reacted with (11)C-acetone in methanol to produce (S)-[(11)C]-exaprolol. Radiochemical purification was performed with RP-HPLC and was followed by Sep-Pak formulation. The labeled product was i.v. injected into male Wistar rats. Brain images were acquired using a microPET Focus 220 and the biodistribution of (11)C was assessed. The radiochemical yield of (S)-[(11)C]-exaprolol was 7% with a total synthesis time of 30 min. Specific activities were >10 GBq/micromol. Brain uptake of the tracer reached a maximum after 15 min. Standardized uptake values were moderate (0.5-0.9) but sufficient for imaging. However, beta-blockade (propranolol, 2.5mg/kg body weight) did not lower tracer uptake in any CNS region and washout from the brain was not accelerated when propranolol was administered 40 min after injection of (S)-[(11)C]-exaprolol. Tracer binding in lung, spleen and erythrocytes was lowered after beta-blockade, but the myocardial uptake of radioactivity was not affected. These data indicate that (S)-[(11)C]-exaprolol is not a suitable beta-adrenoceptor ligand for PET, probably because the in vivo affinity of exaprolol to beta

  4. In vivo visualization of central muscarinic receptors using [11C]quinuclidinyl benzilate and positron emission tomography in baboons.

    PubMed

    Varastet, M; Brouillet, E; Chavoix, C; Prenant, C; Crouzel, C; Stulzaft, O; Bottlaender, M; Cayla, J; Mazière, B; Mazière, M

    1992-03-24

    The muscarinic antagonist, quinuclidinyl benzilate (QNB), labeled with carbon 11 was used as a radioligand to visualize in vivo by positron emission tomography (PET) the central muscarinic acetylcholine receptors (mAChR) in baboons (Papio papio). The binding characteristics of [11C]QNB showed its specific binding to central mAChR. [11C]QNB brain uptake was high in cerebral cortex and striatum, areas that are rich in mAChR, whereas it decreased rapidly in cerebellum, evidencing non-specific binding in this structure that is almost devoid of mAChR. These results are consistent with the known cerebral distribution of mAChR in primates. [11C]QNB specific cerebral binding was enhanced by pretreatment with methyl-QNB, a peripherally acting muscarinic antagonist. Specifically labeled binding sites alone were blocked by prior administration of dexetimide, a muscarinic antagonist. Specific radioactivity was driven out from mAChR-rich regions by atropine and dexetimide, drugs with high affinity for mAChR. This competition was stereospecific since only dexetimide, the pharmacologically active isomer of benzetimide, was able to compete with the radioligand on its binding sites. A relationship between the occupancy of [11C]QNB-labeled receptors by atropine or dexetimide and the concomitant induction of a pharmacological effect was also detected by simultaneous PET scanning and electroencephalographic recording. Since mAChR form an important part of choline receptors in the central nervous system, [11C]QNB appears to be a suitable radiotracer to monitor cerebral physiological or pathological phenomena linked to the cholinergic system in living subjects. PMID:1521561

  5. Molecular imaging of 1p/19q deletion in oligodendroglial tumours with 11C-methionine positron emission tomography

    PubMed Central

    Iwadate, Yasuo; Shinozaki, Natsuki; Matsutani, Tomoo; Uchino, Yoshio; Saeki, Naokatsu

    2016-01-01

    Objective Chromosome 1p/19q deletion is an established prognostic and predictive marker in the WHO grade III oligodendroglial tumours (OT). To estimate the genetic status preoperatively, the authors investigated the correlation between the uptake of 11C-methionine in positron emission tomography (PET) and the 1p/19q status in grades II and III OT. Methods We retrospectively reviewed 144 patients with gliomas who received 11C-methionine PET. 66 cases with grades II–III oligodendrogliomas or oligoastrocytomas underwent fluorescence in situ hybridisation to determine the 1p/19q status. The tissue uptake of 11C-methionine was expressed as the ratio of the maximum standardised uptake value (SUVmax) in tumour areas to the mean SUV (SUVmean) in the contralateral normal brain (tumour-to-normal tissue (T/N) ratio). Results The T/N ratio in 11C-methionine PET was significantly higher in grade III OT than in grade II tumours. The mean T/N ratio of the grade II tumours without 1p/19q deletion was significantly higher than that of the grade II tumours with 1p/19q deletion (mean 2.67 vs 1.94, respectively; p=0.0457). In grade III tumours, the mean T/N ratio of the tumours without 1p/19q deletion was also significantly higher than that of the tumours with 1p/19q deletion (mean 4.83 vs 3.49, respectively; p=0.0261). The rate of IDH1 mutation was lower and the rate of contrast enhancement on MRIs was higher in the 1p/19q non-deleted OT than those with 1p/19q deletion, which may contribute to the high T/N ratio. Conclusions Among suspected OT, 11C-methionine PET may help us preoperatively discriminate tumours with and without 1p/19q deletion. PMID:26848169

  6. Amyloid-β 11C-PiB-PET imaging results from 2 randomized bapineuzumab phase 3 AD trials

    PubMed Central

    Schmidt, Mark E.; Margolin, Richard; Sperling, Reisa; Koeppe, Robert; Mason, Neale S.; Klunk, William E.; Mathis, Chester A.; Salloway, Stephen; Fox, Nick C.; Hill, Derek L.; Les, Andrea S.; Collins, Peter; Gregg, Keith M.; Di, Jianing; Lu, Yuan; Tudor, I. Cristina; Wyman, Bradley T.; Booth, Kevin; Broome, Stephanie; Yuen, Eric; Grundman, Michael; Brashear, H. Robert

    2015-01-01

    Objective: To evaluate the effects of bapineuzumab on brain β-amyloid (Aβ) burden using 11C-Pittsburgh compound B (11C-PiB)-PET. Methods: Two phase 3 clinical trials, 1 each in apolipoprotein APOE ε4 carriers and noncarriers, were conducted in patients with mild to moderate Alzheimer disease dementia. Bapineuzumab, an anti-Aβ monoclonal antibody, or placebo, was administered by IV infusion every 13 weeks for 78 weeks. PET substudies assessed change in brain fibrillar Aβ over 71 weeks using an 11C-PiB-PET standardized uptake value ratio (SUVr) global cortical average (GCA) comprising the average SUVr from 5 cortical regions of interest with cerebellar gray matter as the reference region. Results: A total of 115 carriers and 39 noncarriers were analyzed. The difference (δ) in mean baseline to 71 week change in 11C-PiB-PET GCA between bapineuzumab and placebo was significant in carriers (0.5 mg/kg vs placebo δ = −0.101; p = 0.004) and in pooled analyses of both carriers and noncarriers (0.5 mg/kg vs placebo δ = −0.068; p = 0.027; 1.0 mg/kg vs placebo δ = −0.133; p = 0.028) but not in the noncarrier trial separately. Analyses by individual region of interest and in mild disease yielded findings similar to the main trial results. Conclusions: The 11C-PiB-PET imaging results demonstrated reduction of fibrillar Aβ accumulation in patients with Alzheimer disease treated with bapineuzumab; however, as no clinical benefit was observed, the findings are consistent with the hypotheses that bapineuzumab may not have been initiated early enough in the disease course, the doses were insufficient, or the most critical Aβ species were inadequately targeted. PMID:26208959

  7. Atomic oxygen flux and fluence calculation for Long Duration Exposure Facility (LDEF)

    NASA Technical Reports Server (NTRS)

    Bourassa, Roger J.; Gillis, James R.

    1991-01-01

    The LDEF mission was to study the effects of the space environment on various materials over an extended period of time. One of the important factors for materials degradation in low earth orbit is the atomic oxygen fluxes and fluences experienced by the materials. These fluxes and fluences are a function of orbital parameters, solar and geomagnetic activity, and material surface orientation. Calculations of atomic oxygen fluences and fluxes for the LDEF mission are summarized. Included are descriptions of LDEF orbital parameters, solar and geomagnetic data, computer code FLUXAV, which was used to perform calculations of fluxes and fluences, along with a discussion of the calculated fluxes and fluences.

  8. Effects of salinity build-up on the performance of an anaerobic membrane bioreactor regarding basic water quality parameters and removal of trace organic contaminants.

    PubMed

    Song, Xiaoye; McDonald, James; Price, William E; Khan, Stuart J; Hai, Faisal I; Ngo, Hao H; Guo, Wenshan; Nghiem, Long D

    2016-09-01

    The effects of elevated inorganic salt concentration on anaerobic membrane bioreactor (AnMBR) treatment regarding basic biological performance and trace organic contaminant (TrOC) removal were investigated. A set of 33 TrOCs were selected to represent pharmaceuticals, steroids, and pesticides in municipal wastewater. Results show potential adverse effects of increase in the bioreactor salinity to 15g/L (as NaCl) on the performance of AnMBR with respect to chemical oxygen demand removal, biogas production, and the removal of most hydrophilic TrOCs. Furthermore, a decrease in biomass production was observed as salinity in the bioreactor increased. The removal of most hydrophobic TrOCs was high and was not significantly affected by salinity build-up in the bioreactor. The accumulation of a few persistent TrOCs in the sludge phase was observed, but such accumulation did not vary significantly as salinity in the bioreactor increased. PMID:27262094

  9. Quantitative Photoacoustic Image Reconstruction using Fluence Dependent Chromophores

    PubMed Central

    Cox, B.T.; Laufer, J.G.; Beard, P.C.

    2010-01-01

    In biomedical photoacoustic imaging the images are proportional to the absorbed optical energy density, and not the optical absorption, which makes it difficult to obtain a quantitatively accurate image showing the concentration of a particular absorbing chromophore from photoacoustic measurements alone. Here it is shown that the spatially varying concentration of a chromophore whose absorption becomes zero above a threshold light fluence can be estimated from photoacoustic images obtained at increasing illumination strengths. This technique provides an alternative to model-based multiwavelength approaches to quantitative photoacoustic imaging, and a new approach to photoacoustic molecular and functional imaging. PMID:21258458

  10. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials

    PubMed Central

    Sawani, Shefali; Arora, Vipin; Jaiswal, Shikha; Nikhil, Vineeta

    2014-01-01

    Background: Evaluation of microleakage is important for assessing the success of new restorative materials and methods. Aim and Objectives: Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials. Materials and Methods: Standardized mesi-occlusal (MO) and distoocclusal (DO) Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST) with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC) at the gingival seat. Group 3: Closed-Sandwich technique (CST) with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control — no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation. Results: Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation). Cervical scores of control were more than the exprimental groups (P < 0.05). Less microleakage was observed in CST than OST in all experimental groups (P < 0.05). However, insignificant differences were observed among occlusal scores of different groups (P > 0.05). Conclusion: Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST. PMID:25125847

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

    PubMed Central

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

    2009-01-01

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

  12. No-carrier-added carbon-11-labeled sn-1,2- and sn-1,3-diacylglycerols by (11C)propyl ketene method

    SciTech Connect

    Imahori, Y.; Fujii, R.; Ueda, S.; Ido, T.; Nishino, H.; Moriyama, Y.; Yamamoto, Y.L.; Nakahashi, H. )

    1991-08-01

    This article describes the preparation of sn-1,2-(11C)diacylglycerols and sn-1,3-(11C)diacylglycerols by a no-carrier-added reaction based on a labeling method using (1-11C)propyl ketene, which is one of the most potent acylating agents. (1-11C)Propyl ketene was produced by pyrolytic decomposition of (1-11C)butyric acid and was trapped in pyridine containing L-alpha-palmitoyl-lysophosphatidylcholine, producing L-alpha-palmitoyl-2-(1-11C)butyryl-sn-glycero-3-phosphorylcholine. The authors adopted an enzymatic reaction to remove the phosphorylcholine, in which L-alpha-palmitoyl-2-(1-11C)butyryl-sn-glycero-3-phosphorylcholine was incubated with phospholipase C, hydrolyzing to produce 1-palmitoyl-sn-2-(1-11C)butyrylglycerol. Total synthesis time was about 50 minutes and the specific activity was estimated at 93 GBq/mumol (2.5 Ci/mumol) at end of synthesis. Radiochemical yield was 3.8% based on the trapped 11CO2. sn-1,3-(11C)Diacylglycerol was also synthesized by (1-11C)propyl ketene reaction with 1-palmitoyl-sn-glycerol in a single procedure. The regional brain tissue radioactivities obtained in sn-1,2-(11C)diacylglycerol were higher than those of sn-1,3-(11C)diacylglycerol, and the regional values varied widely. In autoradiography of brain slices from conscious rats, sn-1,2-(11C)diacylglycerol incorporation sites were discretely localized, especially in the amygdala, cerebral cortex, and hippocampus, suggesting that intensive neuronal processing occurred in these areas on the basis of phosphatidylinositol turnover.

  13. Building up rhetorical structure trees

    SciTech Connect

    Marcu, D.

    1996-12-31

    I use the distinction between the nuclei and the satellites that pertain to discourse relations to introduce a compositionality criterion for discourse trees. I provide a first-order formalization of rhetorical structure trees and, on its basis, I derive an algorithm that constructs all the valid rhetorical trees that can be associated with a given discourse.

  14. Monte Carlo simulation of light fluence calculation during pleural PDT

    NASA Astrophysics Data System (ADS)

    Meo, Julia L.; Zhu, Timothy

    2013-03-01

    A thorough understanding of light distribution in the desired tissue is necessary for accurate light dosimetry in PDT. Solving the problem of light dose depends, in part, on the geometry of the tissue to be treated. When considering PDT in the thoracic cavity for treatment of malignant, localized tumors such as those observed in malignant pleural mesothelioma (MPM), changes in light dose caused by the cavity geometry should be accounted for in order to improve treatment efficacy. Cavity-like geometries demonstrate what is known as the "integrating sphere effect" where multiple light scattering off the cavity walls induces an overall increase in light dose in the cavity. We present a Monte Carlo simulation of light fluence based on a spherical and an elliptical cavity geometry with various dimensions. The tissue optical properties as well as the non-scattering medium (air and water) varies. We have also introduced small absorption inside the cavity to simulate the effect of blood absorption. We expand the MC simulation to track photons both within the cavity and in the surrounding cavity walls. Simulations are run for a variety of cavity optical properties determined using spectroscopic methods. We concluded from the MC simulation that the light fluence inside the cavity is inversely proportional to the surface area.

  15. DS02 fluence spectra for neutrons and gamma rays at Hiroshima and Nagasaki with fluence-to-kerma coefficients and transmission factors for sample measurements.

    PubMed

    Egbert, Stephen D; Kerr, George D; Cullings, Harry M

    2007-11-01

    Fluence spectra at several ground distances in Hiroshima and Nagasaki are provided along with associated fluence-to-kerma coefficients from the Dosimetry System 2002 (DS02). Also included are transmission factors for calculating expected responses of in situ sample measurements of neutron activation products such as (32)P,(36)Cl,(39)Ar,(41)Ca, (60)Co,(63)Ni,(152)Eu, and (154)Eu. The free-in-air (FIA) fluences calculated in 2002 are available for 240 angles, 69 energy groups, 101 ground distances, 5 heights, 4 radiation source components, 2 cities. The DS02 code uses these fluences partitioned to a prompt and delayed portion, collapsed to 58 energy groups and restricted to 97 ground distances. This is because the fluence spectra were required to be in the same format that was used in the older Dosimetry System 1986 (DS86) computer code, of which the DS02 computer code is a modification. The 2002 calculation fluences and the collapsed DS02 code fluences are presented and briefly discussed. A report on DS02, which is available on the website at the Radiation Effects Research Foundation, provides tables and figures of the A-bomb neutron and gamma-ray output used as the sources in the 2002 radiation transport calculations. While figures illustrating the fluence spectra at several ground ranges are presented in the DS02 Report, it does not include any tables of the calculated fluence spectra in the DS02 report. This paper provides, at several standard distances from the hypocenter, the numerical information which is required to translate the FIA neutron fluences given in DS02 to a neutron activation measurement or neutron and gamma-ray soft-tissue dose. PMID:17643260

  16. Clinicopathologic and 11C-Pittsburgh compound B implications of Thal amyloid phase across the Alzheimer’s disease spectrum

    PubMed Central

    Lowe, Val J.; Graff-Radford, Neill R.; Liesinger, Amanda M.; Cannon, Ashley; Przybelski, Scott A.; Rawal, Bhupendra; Parisi, Joseph E.; Petersen, Ronald C.; Kantarci, Kejal; Ross, Owen A.; Duara, Ranjan; Knopman, David S.; Jack, Clifford R.; Dickson, Dennis W.

    2015-01-01

    Thal amyloid phase, which describes the pattern of progressive amyloid-β plaque deposition in Alzheimer’s disease, was incorporated into the latest National Institute of Ageing – Alzheimer’s Association neuropathologic assessment guidelines. Amyloid biomarkers (positron emission tomography and cerebrospinal fluid) were included in clinical diagnostic guidelines for Alzheimer’s disease dementia published by the National Institute of Ageing – Alzheimer’s Association and the International Work group. Our first goal was to evaluate the correspondence of Thal amyloid phase to Braak tangle stage and ante-mortem clinical characteristics in a large autopsy cohort. Second, we examined the relevance of Thal amyloid phase in a prospectively-followed autopsied cohort who underwent ante-mortem 11C-Pittsburgh compound B imaging; using the large autopsy cohort to broaden our perspective of 11C-Pittsburgh compound B results. The Mayo Clinic Jacksonville Brain Bank case series (n = 3618) was selected regardless of ante-mortem clinical diagnosis and neuropathologic co-morbidities, and all assigned Thal amyloid phase and Braak tangle stage using thioflavin-S fluorescent microscopy. 11C-Pittsburgh compound B studies from Mayo Clinic Rochester were available for 35 participants scanned within 2 years of death. Cortical 11C-Pittsburgh compound B values were calculated as a standard uptake value ratio normalized to cerebellum grey/white matter. In the high likelihood Alzheimer’s disease brain bank cohort (n = 1375), cases with lower Thal amyloid phases were older at death, had a lower Braak tangle stage, and were less frequently APOE-ε4 positive. Regression modelling in these Alzheimer’s disease cases, showed that Braak tangle stage, but not Thal amyloid phase predicted age at onset, disease duration, and final Mini-Mental State Examination score. In contrast, Thal amyloid phase, but not Braak tangle stage or cerebral amyloid angiopathy predicted 11C-Pittsburgh compound

  17. Clinicopathologic and 11C-Pittsburgh compound B implications of Thal amyloid phase across the Alzheimer's disease spectrum.

    PubMed

    Murray, Melissa E; Lowe, Val J; Graff-Radford, Neill R; Liesinger, Amanda M; Cannon, Ashley; Przybelski, Scott A; Rawal, Bhupendra; Parisi, Joseph E; Petersen, Ronald C; Kantarci, Kejal; Ross, Owen A; Duara, Ranjan; Knopman, David S; Jack, Clifford R; Dickson, Dennis W

    2015-05-01

    Thal amyloid phase, which describes the pattern of progressive amyloid-β plaque deposition in Alzheimer's disease, was incorporated into the latest National Institute of Ageing - Alzheimer's Association neuropathologic assessment guidelines. Amyloid biomarkers (positron emission tomography and cerebrospinal fluid) were included in clinical diagnostic guidelines for Alzheimer's disease dementia published by the National Institute of Ageing - Alzheimer's Association and the International Work group. Our first goal was to evaluate the correspondence of Thal amyloid phase to Braak tangle stage and ante-mortem clinical characteristics in a large autopsy cohort. Second, we examined the relevance of Thal amyloid phase in a prospectively-followed autopsied cohort who underwent ante-mortem (11)C-Pittsburgh compound B imaging; using the large autopsy cohort to broaden our perspective of (11)C-Pittsburgh compound B results. The Mayo Clinic Jacksonville Brain Bank case series (n = 3618) was selected regardless of ante-mortem clinical diagnosis and neuropathologic co-morbidities, and all assigned Thal amyloid phase and Braak tangle stage using thioflavin-S fluorescent microscopy. (11)C-Pittsburgh compound B studies from Mayo Clinic Rochester were available for 35 participants scanned within 2 years of death. Cortical (11)C-Pittsburgh compound B values were calculated as a standard uptake value ratio normalized to cerebellum grey/white matter. In the high likelihood Alzheimer's disease brain bank cohort (n = 1375), cases with lower Thal amyloid phases were older at death, had a lower Braak tangle stage, and were less frequently APOE-ε4 positive. Regression modelling in these Alzheimer's disease cases, showed that Braak tangle stage, but not Thal amyloid phase predicted age at onset, disease duration, and final Mini-Mental State Examination score. In contrast, Thal amyloid phase, but not Braak tangle stage or cerebral amyloid angiopathy predicted (11)C-Pittsburgh compound B

  18. Opioid receptor imaging and displacement studies with [6-O-[11C] methyl]buprenorphine in baboon brain.

    PubMed

    Galynker, I; Schlyer, D J; Dewey, S L; Fowler, J S; Logan, J; Gatley, S J; MacGregor, R R; Ferrieri, R A; Holland, M J; Brodie, J; Simon, E; Wolf, A P

    1996-04-01

    Buprenorphine (BPN) is a mixed opiate agonist-antagonist used as an analgesic and in the treatment of opiate addiction. We have used [6-O-[11C]methyl]buprenorphine ([11C]BPN) to measure the regional distribution in baboon brain, the test-retest stability of repeated studies in the same animal, the displacement of the labeled drug by naloxone in vivo, and the tissue distribution in mice. The regional distribution of radioactivity in baboon brain determined with PET was striatum > thalamus > cingulate gyrus > frontal cortex > parietal cortex > occipital cortex > cerebellum. This distribution corresponded to opiate receptor density and to previously published data (37). The tracer uptake in adult female baboons showed no significant variation in serial scans in the same baboon with no intervention in the same scanning session. HPLC analysis of baboon plasma showed the presence of labeled metabolites with 92% +/- 2.2% and 43% +/- 14.4% of the intact tracer remaining at 5 and 30 min, respectively. Naloxone, an opiate receptor antagonist, administered 30-40 min after tracer injection at a dose of 1.0 mg/kg i.v., reduced [11C]BPN binding in thalamus, striatum, cingulate gyrus, and frontal cortex to values 0.25 to 0.60 of that with no intervention. There were minimal (< 15%) effects on cerebellum. Naloxone treatment significantly reduced the slope of the Patlak plot in receptor-containing regions. These results demonstrate that [11C]BPN can be displaced by naloxone in vivo, and they affirm the feasibility of using this tracer and displacement methodology for short-term kinetics studies with PET. Mouse tissue distribution data were used to estimate the radiation dosimetry to humans. The critical organ was the small intestine, with a radiation dose estimate to humans of 117 nrad/mCi. PMID:8782244

  19. 11C-Methionine positron emission tomography-computed tomography in localization of methoxyisobutyl isonitrile negative ectopic parathyroid adenoma

    PubMed Central

    Seniaray, Nikhil; Sharma, Harshul; Arbind, Arpana; Jaimini, Abhinav; D’souza, Maria; Saw, Sanjeev; Hazari, Puja Panwar; Mishra, A. K.; Sharma, Rajnish; Mondal, Anupam

    2016-01-01

    Primary hyperparathyroidism is caused by parathyroid adenomas in 85% of the cases. Since parathyroid adenomas are known for their ectopic location, presurgical localization of the suspected site of adenoma is desirable. However, current imaging modalities are not always successful in localizing ectopic parathyroid adenomas. The aim of this case report is to show that 11C-methionine positron emission tomography could accurately localize ectopic parathyroid adenomas in patients in whom conventional imaging had failed or is inconclusive. PMID:26917896

  20. Unstable nuclei in coherent dissociation of relativistic nuclei 7,9Be, 10B and 10,11C

    NASA Astrophysics Data System (ADS)

    Artemenkov, D. A.; Bradnova, V.; Firu, E.; Kornegrutsa, N. K.; Haiduc, M.; Mamatkulov, K. Z.; Kattabekov, R. R.; Neagu, A.; Rukoyatkin, P. A.; Rusakova, V. V.; Sarkisyan, V. R.; Stanoeva, R.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2016-06-01

    Contribution of the unstable nuclei 7Be, 8Be and ®B into coherent dissociation events (“white” stars) of relativistic nuclei 7,9Be, 10B and 10,11C is under study on the basis of a nuclear track emulsion exposed to beams of the JINR Nuclotron. Distributions over the opening angle of α-pairs indicate to a simultaneous presence of virtual 8Beg.s. and 8Be2+ states in the ground states of the 9Be and 10C nuclei. The core 9B is manifested in the 10C nucleus with a probability of (30 ± 4)%, Selection of the 10C “white” stars accompanied by 8Beg.s. (9B) leads to the appearance in the excitation energy distribution of 2α2p “quartets” of the distinct peak with a maximum at 4.1 ± 0.3 MeV. 8Beg.s. decays are presented in 21% 2He + 2H and 19% in the 3He of the all 11C “white” stars. 9Bg.s. decays are identified in “white” stars 11C → 2He + 2H constituting 14% of the 11C “white” stars. The 9B nucleus. is manifested in the “white” stars 10B → 2He + 2H with a probability of (9 ± 1)%. For the 10B case yield of 8Beg.s. nuclei with the respect to 9B is about a factor of 3 higher than 9B.

  1. The fluence threshold of femtosecond laser blackening of metals: The effect of laser-induced ripples

    NASA Astrophysics Data System (ADS)

    Ou, Zhigui; Huang, Min; Zhao, Fuli

    2016-05-01

    With the primary controlling factor of the laser fluence, we have investigated femtosecond laser blackening of stainless steel, brass, and aluminum in visible light range. In general, low reflectance about 5% can be achieved in appropriate ranges of laser fluences for all the treated metal surfaces. Significantly, towards stainless steel and brass a fluence threshold of blackening emerges unusually: a dramatic reflectance decline occurs in a specific, narrow fluence range. In contrast, towards aluminum the reflectance declines steadily over a wide fluence range instead of the threshold-like behavior from steel and brass. The morphological characteristics and corresponding reflectance spectra of the treated surfaces indicates that the blackening threshold of stainless steel and brass corresponds to the fluence threshold of laser-induced subwavelength ripples. Such periodic ripples growing rapidly near ablation threshold absorb visible light efficiently through grating coupling and cavity trapping promoted by surface plasmon polaritons. Whereas, for aluminum, with fluence increasing the looming ripples are greatly suppressed by re-deposited nanoparticle aggregates that present intrinsic colors other than black, and until the formation of large scale "ravines" provided with strong light-trapping, sufficient blackening is achieved. In short, there are different fluence dependencies for femtosecond laser blackening of metals, and the specific blackening fluence threshold for certain metals in the visible range originates in the definite fluence threshold of femtosecond laser-induced ripples.

  2. Synthesis and tissue biodistribution of [{omega}-{sup 11}C]palmitic acid. A novel PET imagining agent for cardiac fatty acid metabolism

    SciTech Connect

    Buckman, B.O.; VanBrocklin, H.F.; Katzenellenbogen, J.A.; Dence, C.S.; Bergmann, S.R.; Welch, M.J.

    1994-12-31

    In order to diagnose patients with medium-chain acyl-CoA dehydrogenase deficiency with a noninvasive diagnostic technique such as positron emission tomography, they have developed a synthesis of [{omega}-{sup 11}C]palmitic acid. The radiochemical synthesis was achieved by coupling an alkylfuran Grignard reagent (7) with [{sup 11}C]methyl iodide, followed by rapid oxidative cleavage of the furan ring to the carboxylate using ruthenium tetraoxide. Tissue biodistribution studies in rags comparing [{omega}-{sup 11}C]palmitic acid and [1-{sup 11}C]palmitic acid show that the %ID/g and %ID/organ in the heart tissue after administration of [{omega}-{sup 11}C]palmitic acid is approximately 50% greater than after administration of [1-{sup 11}C]palmitic acid, due to the diminished metabolism of the [{omega}-{sup 11}C]palmitic acid. These studies show as well, low uptake in nontarget tissues (blood, lung, kidney, and muscle). PET images of a dog heart obtained after administration of [{omega}-{sup 11}C]- and [1-{sup 11}C]palmitic acid show virtually identical uptake and distribution in the myocardium. The differing cardiac washout of labeled palmitates measured by dynamic PET studies may allow diagnosis of disorders in cardiac fatty acid metabolism.

  3. Effective source size, radial, angular and energy spread of therapeutic 11C positron emitter beams produced by 12C fragmentation

    NASA Astrophysics Data System (ADS)

    Lazzeroni, Marta; Brahme, Anders

    2014-02-01

    The use of positron emitter light ion beams in combination with PET (Positron Emission Tomography) and PET-CT (Computed Tomography) imaging could significantly improve treatment verification and dose delivery imaging during radiation therapy. The present study is dedicated to the analysis of the beam quality in terms of the effective source size, as well as radial, angular and energy spread of the 11C ion beam produced by projectile fragmentation of a primary point monodirectional and monoenergetic 12C ion beam in a dedicated range shifter of different materials. This study was performed combining analytical methods describing the transport of particles in matter and the Monte Carlo code SHIELD-HIT+. A high brilliance and production yield of 11C fragments with a small effective source size and emittance is best achieved with a decelerator made of two media: a first liquid hydrogen section of about 20 cm followed by a hydrogen rich section of variable length. The calculated intensity of the produced 11C ion beam ranges from about 5% to 8% of the primary 12C beam intensity depending on the exit energy and the acceptance of the beam transport system. The angular spread is lower than 1 degree for all the materials studied, but the brilliance of the beam is the highest with the proposed mixed decelerator.

  4. Use of ( sup 11 C)aminocyclohexanecarboxylate for the measurement of amino acid uptake and distribution volume in human brain

    SciTech Connect

    Koeppe, R.A.; Mangner, T.; Betz, A.L.; Shulkin, B.L.; Allen, R.; Kollros, P.; Kuhl, D.E.; Agranoff, B.W. )

    1990-09-01

    A quantitative positron emission tomographic (PET) method to measure amino acid blood-brain barrier (BBB) transport rate and tissue distribution volume (DV) has been developed using {sup 11}C-labeled aminocyclohexanecarboxylate (ACHC), a nonmetabolized amino acid analogue. Dynamic PET data were acquired as a series of 15 scans covering a total of 60 min and analyzed by means of a two-compartment, two-parameter model. Functional images were calculated for the amino acid transport rate constants across the BBB and the amino acid DV in the brain. Results show ({sup 11}C)ACHC to have an influx rate constant in gray matter of approximately 0.03-0.04 ml g-1 min-1, indicating a single-pass extraction fraction of approximately 5-7%. The intersubject coefficient of variation was approximately 15% while intrasubject variability of repeat scans was only slightly greater than 5%. Studies were performed in 15 young normal volunteer control subjects, 5 elderly controls, 7 patients with probable Alzheimer's disease, and one patient with phenylketonuria. Results indicate that ({sup 11}C)-ACHC will serve as the basis of a method for measuring amino acid transport rate and DV in the normal and pathological human brain.

  5. Involvement of SOCS3 in regulation of CD11c+ dendritic cell-derived osteoclastogenesis and severe alveolar bone loss.

    PubMed

    Zhang, Xiaoxia; Alnaeeli, Mawadda; Singh, Bhagirath; Teng, Yen-Tung A

    2009-05-01

    To investigate the role of suppressor of cytokine signaling (SOCS) molecules in periodontal immunity and RANKL-mediated dendritic cell (DC)-associated osteoclastogenesis, we analyzed SOCS expression profiles in CD4(+) T cells and the effect of SOCS3 expression in CD11c(+) DCs during periodontal inflammation-induced osteoclastogenesis and bone loss in nonobese diabetic (NOD) versus humanized NOD/SCID mice. Our results of ex vivo and in vitro analyses showed that (i) there is significantly higher SOCS3 expression associated with RANKL(+) T-cell-mediated bone loss in correlation with increased CD11c(+) DC-mediated osteoclastogenesis; (ii) the transfection of CD11c(+) DC using an adenoviral vector carrying a dominant negative SOCS3 gene significantly abrogates TRAP and bone-resorptive activity; and (iii) inflammation-induced TRAP expression, bone resorption, and SOCS3 activity are not associated with any detectable change in the expression levels of TRAF6 and mitogen-activated protein kinase signaling adaptors (i.e., Erk, Jnk, p38, and Akt) in RANKL(+) T cells. We conclude that SOCS3 plays a critical role in modulating cytokine signaling involved in RANKL-mediated DC-derived osteoclastogenesis during immune interactions with T cells and diabetes-associated severe inflammation-induced alveolar bone loss. Therefore, the development of SOCS3 inhibitors may have therapeutic potential as the target to halt inflammation-induced bone loss under pathological conditions in vivo. PMID:19255186

  6. Kilometer-scale, late Miocene and early Pliocene surface uplift in East Greenland: tectonic forerunners for the build-up of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.

    2015-04-01

    The tectonic origin of late Neogene uplift along NE Atlantic margins has been questioned. Evidence for these movements - such as the recent denudation of mountain ranges and abundant, late Cenozoic coarse sediment near them - has been explained as a result of climate change (Molnar and England, 1990). Identification of the causal relationship between uplift, tectonics and climate deterioration during the late Neogene thus critically depends on defining temporal relation between these events. We have previously argued that the elevated plateaux in East and West Greenland are the result of three tectonic phases of uplift and erosion (Bonow et al., 2014; Japsen et al., 2014). A late Eocene phase of uplift led to formation of a Palaeogene erosion surface near sea level. Uplift of this surface in the late Miocene led to formation of a lower, Neogene surface by incision below the uplifted Palaeogene surface. Finally, a Pliocene phase led to incision of valleys and fjords below the uplifted Neogene surface, resulting in mountain peaks reaching 3.7 km and 2.1 km a.s.l. in East and West Greenland, respectively. Data from West Greenland only provide broad constraints on the timing of the Pliocene phase, and we have not yet been able to define the timing of this phase firmly in the east. Here we present new apatite fission-track data from East Greenland that clearly constrain the timing of late Miocene and early Pliocene events of uplift and exhumation. It is thus clear that the final phase of Cenozoic tectonic uplift preceded the onset of large-scale glaciations in the late Pliocene to Pleistocene. Solgaard et al. (2013) showed that the the build-up of the Greenland Ice Sheet could not initiate in the case of the low-lying and almost flat topography in Greenland prior to the two phases of late Neogene uplift. Furthermore, these results showed that Early Pliocene uplift led to the final formation of the present-day, high coastal mountains in East Greenland that provided

  7. Evolutionary paths among different red galaxy types at 0.3 < z < 1.5 and the build-up of massive E-S0's

    NASA Astrophysics Data System (ADS)

    Gallego, Jesús; Prieto, Mercedes; Eliche-Moral, M. Carmen; Balcells, Marc; Cristóbal-Hornillos, David; Erwin, Peter; Abreu, David; Domínguez-Palmero, Lilian; Hempel, Angela; López-Sanjuan, Carlos; Guzmán, Rafael; Pérez-González, Pablo G.; Barro, Guillermo; Zamorano, Jaime

    2013-07-01

    Some recent observations seem to disagree with hierarchical theories of galaxy formation on the role of major mergers in a late build-up of massive early-type galaxies. We re-address this question by analysing the morphology, structural distortion level, and star formation enhancement of a sample of massive galaxies (M* > 5 × 1010M⊙) lying on the Red Sequence and its surroundings at 0.3 < z < 1.5. We have used an initial sample of ~1800 sources with Ks < 20.5 mag over an area ~155 arcmin2 on the Groth Strip, combining data from the Rainbow Extragalactic Database and the GOYA Survey. Red galaxy classes that can be directly associated to intermediate stages of major mergers and to their final products have been defined. For the first time we report observationally the existence of a dominant evolutionary path among massive red galaxies at 0.6 < z < 1.5, consisting in the conversion of irregular disks into irregular spheroids, and of these ones into regular spheroids. This result points to: 1) the massive red regular galaxies at low redshifts derive from the irregular ones populating the Red Sequence and its neighbourhood at earlier epochs up to z ~ 1.5; 2) the progenitors of the bulk of present-day massive red regular galaxies have been blue disks that have migrated to the Red Sequence majoritarily through major mergers at 0.6 < z < 1.2 (these mergers thus starting at z ~ 1.5); 3) the formation of E-S0's that end up with M* > 1011M⊙ at z = 0 through gas-rich major mergers has frozen since z ~ 0.6. Our results support that major mergers have played the dominant role in the definitive build-up of present-day E-S0's with M* > 1011M⊙ at 0.6 < z < 1.2, in good agreement with the hierarchical scenario proposed in the Eliche-Moral et al. (2010a) model (see also Eliche-Moral et al. 2010b). This study is published in Prieto et al. (2012). Supported by the Spanish Ministry of Science and Innovation (MICINN) under projects AYA2009-10368, AYA2006-12955, AYA2010-21887-C04

  8. The Meteoroid Fluence at Mars Due to Comet Siding Spring

    NASA Technical Reports Server (NTRS)

    Moorhead, Althea V.

    2014-01-01

    Long-period comet C/2013 A1 (Siding Spring) is headed for a close encounter with Mars on 2014 Oct 19. A collision between the comet and the planet has been ruled out, but the comets coma may envelop Mars and its man-made satellites. We present an analytic model of the dust component of cometary comae that describes the spatial distribution of cometary dust and meteoroids and their size distribution. If the coma reaches Mars, we estimate a total incident particle fluence on the planet and its satellites of 0.01 particles per square meter. We compare our model with numerical simulations, data from past comet missions, and recent Siding Spring observations.

  9. A common fluence threshold for first positive and second positive phototropism in Arabidopsis thaliana

    NASA Technical Reports Server (NTRS)

    Janoudi, A.; Poff, K. L.

    1990-01-01

    The relationship between the amount of light and the amount of response for any photobiological process can be based on the number of incident quanta per unit time (fluence rate-response) or on the number of incident quanta during a given period of irradiation (fluence-response). Fluence-response and fluence rate-response relationships have been measured for second positive phototropism by seedlings of Arabidopsis thaliana. The fluence-response relationships exhibit a single limiting threshold at about 0.01 micromole per square meter when measured at fluence rates from 2.4 x 10(-5) to 6.5 x 10(-3) micromoles per square meter per second. The threshold values in the fluence rate-response curves decrease with increasing time of irradiation, but show a common fluence threshold at about 0.01 micromole per square meter. These thresholds are the same as the threshold of about 0.01 micromole per square meter measured for first positive phototropism. Based on these data, it is suggested that second positive curvature has a threshold in time of about 10 minutes. Moreover, if the times of irradiation exceed the time threshold, there is a single limiting fluence threshold at about 0.01 micromole per square meter. Thus, the limiting fluence threshold for second positive phototropism is the same as the fluence threshold for first positive phototropism. Based on these data, we suggest that this common fluence threshold for first positive and second positive phototropism is set by a single photoreceptor pigment system.

  10. Increase of bulk optical damage threshold fluences of KDP crystals by laser irradiation and heat treatment

    DOEpatents

    Swain, J.E.; Stokowski, S.E.; Milam, D.; Kennedy, G.C.; Rainer, F.

    1982-07-07

    The bulk optical damage threshold fluence of potassium dihydrogen phosphate (KDP) crystals is increased by irradiating the crystals with laser pulses of duration 1 to 20 nanoseconds of increasing fluence, below the optical damage threshold fluence for untreated crystals, or by baking the crystals for times of the order of 24 hours at temperatures of 110 to 165/sup 0/C, or by a combination of laser irradiation and baking.

  11. A Common Fluence Threshold for First Positive and Second Positive Phototropism in Arabidopsis thaliana1

    PubMed Central

    Janoudi, Abdul; Poff, Kenneth L.

    1990-01-01

    The relationship between the amount of light and the amount of response for any photobiological process can be based on the number of incident quanta per unit time (fluence rate-response) or on the number of incident quanta during a given period of irradiation (fluence-response). Fluence-response and fluence rate-response relationships have been measured for second positive phototropism by seedlings of Arabidopsis thaliana. The fluence-response relationships exhibit a single limiting threshold at about 0.01 micromole per square meter when measured at fluence rates from 2.4 × 10−5 to 6.5 × 10−3 micromoles per square meter per second. The threshold values in the fluence rateresponse curves decrease with increasing time of irradiation, but show a common fluence threshold at about 0.01 micromole per square meter. These thresholds are the same as the threshold of about 0.01 micromole per square meter measured for first positive phototropism. Based on these data, it is suggested that second positive curvature has a threshold in time of about 10 minutes. Moreover, if the times of irradiation exceed the time threshold, there is a single limiting fluence threshold at about 0.01 micromole per square meter. Thus, the limiting fluence threshold for second positive phototropism is the same as the fluence threshold for first positive phototropism. Based on these data, we suggest that this common fluence threshold for first positive and second positive phototropism is set by a single photoreceptor pigment system. PMID:11537470

  12. High-Resolution Linkage and Quantitative Trait Locus Mapping Aided by Genome Survey Sequencing: Building Up An Integrative Genomic Framework for a Bivalve Mollusc

    PubMed Central

    Jiao, Wenqian; Fu, Xiaoteng; Dou, Jinzhuang; Li, Hengde; Su, Hailin; Mao, Junxia; Yu, Qian; Zhang, Lingling; Hu, Xiaoli; Huang, Xiaoting; Wang, Yangfan; Wang, Shi; Bao, Zhenmin

    2014-01-01

    Genetic linkage maps are indispensable tools in genetic and genomic studies. Recent development of genotyping-by-sequencing (GBS) methods holds great promise for constructing high-resolution linkage maps in organisms lacking extensive genomic resources. In the present study, linkage mapping was conducted for a bivalve mollusc (Chlamys farreri) using a newly developed GBS method—2b-restriction site-associated DNA (2b-RAD). Genome survey sequencing was performed to generate a preliminary reference genome that was utilized to facilitate linkage and quantitative trait locus (QTL) mapping in C. farreri. A high-resolution linkage map was constructed with a marker density (3806) that has, to our knowledge, never been achieved in any other molluscs. The linkage map covered nearly the whole genome (99.5%) with a resolution of 0.41 cM. QTL mapping and association analysis congruously revealed two growth-related QTLs and one potential sex-determination region. An important candidate QTL gene named PROP1, which functions in the regulation of growth hormone production in vertebrates, was identified from the growth-related QTL region detected on the linkage group LG3. We demonstrate that this linkage map can serve as an important platform for improving genome assembly and unifying multiple genomic resources. Our study, therefore, exemplifies how to build up an integrative genomic framework in a non-model organism. PMID:24107803

  13. HSRL-2 Observations of Aerosol Variability During an Aerosol Build-up Event in Houston and Comparisons With WRF-Chem

    NASA Technical Reports Server (NTRS)

    Burton, Sharon P.; Saide, Pablo; Sawamura, Patricia; Hostetler, Chris; Ferrare, Rich; Scarino, Amy Jo; Berkoff, Tim; Harper, David; Cook, Tony; Rogers, Ray; Carmichael, Greg

    2015-01-01

    The NASA Langley airborne multi-wavelength High Spectral Resolution Lidar (HSRL-2) provides vertical distribution of aerosol optical properties as curtains of aerosol extinction, backscatter and depolarization along the flight track, plus intensive properties that are used to infer aerosol type and external mixing of types. Deployed aboard the NASA Langley King Air on the DISCOVER-AQ field mission in Houston in September 2013, HSRL-2 flew a pattern that included 18 ground sites, repeated four times a day, coordinated with a suite of airborne in situ measurements. The horizontally and vertically resolved curtains of HSRL-2 measurements give an unparalleled view of the spatial and temporal variability of aerosol, which provide broad context for interpreting other measurements and models. Detailed comparisons of aerosol extinction are made with the WRF-Chem chemical transport model along the HSRL-2 flight path. The period from Sept. 11-14 is notable for a large aerosol build-up and persistent smoke layers. We investigate the aerosol properties using the vertically resolved HSRL-2 measurements and aerosol typing analysis plus WRFChem model tracers and back trajectories, and modeling of humidification effects.

  14. Build-up of an antimicrobial multilayer coating on a textile support based on a methylene blue-poly(cyclodextrin) complex.

    PubMed

    Martin, Adeline; Tabary, Nicolas; Chai, Feng; Leclercq, Laurent; Junthip, Jatupol; Aubert-Viard, François; Neut, Christel; Weltrowski, Marek; Blanchemain, Nicolas; Martel, Bernard

    2013-12-01

    The aim of this work was to develop an antibacterial multilayer coating activated with methylene blue (MB) and based on chitosan (CHT) and cyclodextrin polyelectrolyte (polyCD) onto a non-woven polyethylene terephthalate (PET) textile support. The MB-free and MB-loaded systems were built-up by applying the dip-coating technique, alternating soak cycles of the PET textile preliminarily modified with carboxylate groups in CHT and in polyCD or polyCD/MB complex solutions. The layer-by-layer assembly build-up was followed by optical waveguide lightmode spectroscopy on the one hand and by gravimetry once it was applied on the textile substrate on the other hand. Two chitosan grades were used, low molecular weight (CHT-L) and medium molecular weight (CHT-M). The influence of the molar ratio CD/MB in the polyCD solutions was varied and finally the system underwent a post reticulation with genipin. Such parameters influences were investigated with regard to the loading capacity in MB of the systems, the release kinetics profiles of MB in pure water, phosphate buffer and MEM media, and the degradation of the self-assembled coating in the same media. Finally, biological and microbiological tests were performed to demonstrate the cytocompatibility of the systems and their ability to display a sustained antibacterial effect of the device through the MB prolonged release. PMID:24280742

  15. Ecloud Build-Up Simulations for the FNAL MI for a Mixed Fill Pattern: Dependence on Peak SEY and Pulse Intensity During the Ramp

    SciTech Connect

    Furman, M. A.

    2010-12-11

    We present simulation results of the build-up of the electron-cloud density n{sub e} in three regions of the FNAL Main Injector (MI) for a beam fill pattern made up of 5 double booster batches followed by a 6th single batch. We vary the pulse intensity in the range N{sub t} = (2-5) x 10{sup 13}, and the beam kinetic energy in the range E{sub k} = 8-120 GeV. We assume a secondary electron emission model qualitatively corresponding to TiN, except that we let the peak value of the secondary electron yield (SEY) {delta}{sub max} vary as a free parameter in a fairly broad range. Our main conclusions are: (1) At fixed N{sub t} there is a clear threshold behavior of n{sub e} as a function of {delta}{sub max} in the range {approx} 1.1-1.3. (2) At fixed {delta}{sub max}, there is a threshold behavior of n{sub e} as a function of N{sub t} provided {delta}{sub max} is sufficiently high; the threshold value of N{sub t} is a function of the characteristics of the region being simulated. (3) The dependence on E{sub k} is weak except possibly at transition energy. Most of these results were informally presented to the relevant MI personnel in April 2010.

  16. Heavy Ion Irradiation Fluence Dependence for Single-Event Upsets of NAND Flash Memory

    NASA Technical Reports Server (NTRS)

    Chen, Dakai; Wilcox, Edward; Ladbury, Raymond; Kim, Hak; Phan, Anthony; Seidleck, Christina; LaBel, Kenneth

    2016-01-01

    We investigated the single-event effect (SEE) susceptibility of the Micron 16 nm NAND flash, and found the single-event upset (SEU) cross section varied inversely with fluence. The SEU cross section decreased with increasing fluence. We attribute the effect to the variable upset sensitivities of the memory cells. The current test standards and procedures assume that SEU follow a Poisson process and do not take into account the variability in the error rate with fluence. Therefore, heavy ion irradiation of devices with variable upset sensitivity distribution using typical fluence levels may underestimate the cross section and on-orbit event rate.

  17. Labelling of the solvent DMSO as side reaction of methylations with n.c.a. [11C]CH3I.

    PubMed

    Klein, A T; Holschbach, M

    2001-09-01

    Competing labelling of solvent dimethyl sulfoxide (DMSO) can occur during the 11C-methylation of amine precursors. A kinetic analysis of the methylation reaction of DMSO with n.c.a. [11C]CH3I was performed at 120 degrees C resulting in rate constants. The rate constant for the formation of the intermediate, methylated DMSO ([11C]DMSO-M), is compared to the reaction of [11C]CH3I with two tertiary amines, namely Dexetimide and Desmethyloxotremorine-M. The specific activity of the labelled product is reduced due to partial 12C-methylation of the precursor amines by [11C]DMSO-M in cases of significant DMSO labelling as side reaction. PMID:11515652

  18. The fatty acid amide hydrolase C385A variant affects brain binding of the positron emission tomography tracer [11C]CURB

    PubMed Central

    Boileau, Isabelle; Tyndale, Rachel F; Williams, Belinda; Mansouri, Esmaeil; Westwood, Duncan J; Foll, Bernard Le; Rusjan, Pablo M; Mizrahi, Romina; De Luca, Vincenzo; Zhou, Qian; Wilson, Alan A; Houle, Sylvain; Kish, Stephen J; Tong, Junchao

    2015-01-01

    The common functional single-nucleotide polymorphism (rs324420, C385A) of the endocannabinoid inactivating enzyme fatty acid amide hydrolase (FAAH) has been associated with anxiety disorder relevant phenotype and risk for addictions. Here, we tested whether the FAAH polymorphism affects in vivo binding of the FAAH positron emission tomography (PET) probe [11C]CURB ([11C-carbonyl]-6-hydroxy-[1,10-biphenyl]-3-yl cyclohexylcarbamate (URB694)). Participants (n=24) completed one [11C]CURB/PET scan and were genotyped for rs324420. Relative to C/C (58%), A-allele carriers (42%) had 23% lower [11C]CURB binding (λk3) in brain. We report evidence that the genetic variant rs324420 in FAAH is associated with measurable differences in brain FAAH binding as per PET [11C]CURB measurement. PMID:26036940

  19. Dopamine response to psychosocial stress in chronic cannabis users: a PET study with [11C]-+-PHNO.

    PubMed

    Mizrahi, Romina; Suridjan, Ivonne; Kenk, Miran; George, Tony P; Wilson, Alan; Houle, Sylvain; Rusjan, Pablo

    2013-03-01

    A number of addictions have been linked with decreased striatal dopamine (DA) receptor availability and DA release. Stress has a key role in cannabis craving, as well as in modulation of dopaminergic signaling. The present study aimed to assess DA release in response to a laboratory stress task with [(11)C]-(+)-PHNO positron emission tomography in cannabis users (CU). Thirteen healthy CU and 12 healthy volunteers (HV) were scanned during a sensorimotor control task (SMCT) and under a stress condition using the validated Montreal imaging stress task (MIST). The simplified reference tissue model (SRTM) was used to obtain binding potential (BP(ND)) in striatal subdivisions: limbic striatum (LST), associative striatum (AST), and sensorimotor striatum (SMST). Stress-induced DA release (indexed as a percentage of reduction in [(11)C]-(+)-PHNO BP (ND)) between CU and HV was tested with analysis of variance. SMCT BP(ND) was significantly higher in CU compared with HV in the AST (F=10.38, p=0.003), LST (F=4.95, p=0.036), SMST (F=4.33, p=0.048), and whole striatum (F=9.02, p=0.006). Percentage of displacement (change in BP(ND) between SMCT and MIST PET scans) was not significantly different across groups in any brain region, except in the GP (-5.03±14.6 in CU, compared with 6.15±12.1 in HV; F=4.39, p=0.049). Duration of cannabis use was significantly associated with stress-induced [(11)C]-(+)-PHNO displacement by endogenous DA in the LST (r=0.566, p=0.044), with no effect in any other brain region. In conclusion, despite an increase in striatal BP(ND) observed during the control task, chronic cannabis use is not associated with alterations in stress-induced DA release. PMID:23212454

  20. Determination of [11C]Rifampin Pharmacokinetics within Mycobacterium tuberculosis-Infected Mice by Using Dynamic Positron Emission Tomography Bioimaging

    PubMed Central

    DeMarco, Vincent P.; Ordonez, Alvaro A.; Klunk, Mariah; Prideaux, Brendan; Wang, Hui; Zhuo, Zhang; Tonge, Peter J.; Dannals, Robert F.; Holt, Daniel P.; Lee, Carlton K. K.; Weinstein, Edward A.; Dartois, Véronique; Dooley, Kelly E.

    2015-01-01

    Information about intralesional pharmacokinetics (PK) and spatial distribution of tuberculosis (TB) drugs is limited and has not been used to optimize dosing recommendations for new or existing drugs. While new techniques can detect drugs and their metabolites within TB granulomas, they are invasive, rely on accurate resection of tissues, and do not capture dynamic drug distribution in the tissues of interest. In this study, we assessed the in situ distribution of 11C-labeled rifampin in live, Mycobacterium tuberculosis-infected mice that develop necrotic lesions akin to human disease. Dynamic positron emission tomography (PET) imaging was performed over 60 min after injection of [11C]rifampin as a microdose, standardized uptake values (SUV) were calculated, and noncompartmental analysis was used to estimate PK parameters in compartments of interest. [11C]rifampin was rapidly distributed to all parts of the body and quickly localized to the liver. Areas under the concentration-time curve for the first 60 min (AUC0–60) in infected and uninfected mice were similar for liver, blood, and brain compartments (P > 0.53) and were uniformly low in brain (10 to 20% of blood values). However, lower concentrations were noted in necrotic lung tissues of infected mice than in healthy lungs (P = 0.03). Ex vivo two-dimensional matrix-assisted laser desorption ionization (MALDI) imaging confirmed restricted penetration of rifampin into necrotic lung lesions. Noninvasive bioimaging can be used to assess the distribution of drugs into compartments of interest, with potential applications for TB drug regimen development. PMID:26169396

  1. Compartmental analysis of washout effect in rat brain: in-beam OpenPET measurement using a 11C beam

    NASA Astrophysics Data System (ADS)

    Hirano, Yoshiyuki; Kinouchi, Shoko; Ikoma, Yoko; Yoshida, Eiji; Wakizaka, Hidekazu; Ito, Hiroshi; Yamaya, Taiga

    2013-12-01

    In-beam positron emission tomography (PET) is expected to enable visualization of a dose verification using positron emitters (β+ decay). For accurate dose verification, correction of the washout of the positron emitters should be made. In addition, the quantitative washout rate has a potential usefulness as a diagnostic index, but modeling for this has not been studied yet. In this paper, therefore, we applied compartment analyses to in-beam PET data acquired by our small OpenPET prototype, which has a physically opened field-of-view (FOV) between two detector rings. A rat brain was located at the FOV and was irradiated by a 11C beam. Time activity curves of the irradiated field were measured immediately after the irradiations, and the washout rate was obtained based on two models: the two-washout model (medium decay, k2m; slow decay, k2s) developed in a study of rabbit irradiation; and the two-compartment model used in nuclear medicine, where efflux from tissue to blood (k2), influx (k3) and efflux (k4) from the first to second compartments in tissue were evaluated. The observed k2m and k2s were 0.34 and 0.005 min-1, respectively, which was consistent with the rabbit study. Also k2m was close to the washout rate in cerebral blood flow (CBF) measurements by dynamic PET with 15O-water, while, k2, k3, and k4 were 0.16, 0.15 and 0.007 min-1. Our present work suggested the dynamics of 11C might be relevant to CBF or permeability of a molecule containing 11C atoms might be regulated by a transporter because the k2 was relatively low compared with a simple diffusion tracer.

  2. ATP11C is a major flippase in human erythrocytes and its defect causes congenital hemolytic anemia

    PubMed Central

    Arashiki, Nobuto; Takakuwa, Yuichi; Mohandas, Narla; Hale, John; Yoshida, Kenichi; Ogura, Hiromi; Utsugisawa, Taiju; Ohga, Shouichi; Miyano, Satoru; Ogawa, Seishi; Kojima, Seiji; Kanno, Hitoshi

    2016-01-01

    Phosphatidylserine is localized exclusively to the inner leaflet of the membrane lipid bilayer of most cells, including erythrocytes. This asymmetric distribution is critical for the survival of erythrocytes in circulation since externalized phosphatidylserine is a phagocytic signal for splenic macrophages. Flippases are P-IV ATPase family proteins that actively transport phosphatidylserine from the outer to inner leaflet. It has not yet been determined which of the 14 members of this family of proteins is the flippase in human erythrocytes. Herein, we report that ATP11C encodes a major flippase in human erythrocytes, and a genetic mutation identified in a male patient caused congenital hemolytic anemia inherited as an X-linked recessive trait. Phosphatidylserine internalization in erythrocytes with the mutant ATP11C was decreased 10-fold compared to that of the control, functionally establishing that ATP11C is a major flippase in human erythrocytes. Contrary to our expectations phosphatidylserine was retained in the inner leaflet of the majority of mature erythrocytes from both controls and the patient, suggesting that phosphatidylserine cannot be externalized as long as scramblase is inactive. Phosphatidylserine-exposing cells were found only in the densest senescent cells (0.1% of total) in which scramblase was activated by increased Ca2+ concentration: the percentage of these phosphatidylserine-exposing cells was increased in the patient’s senescent cells accounting for his mild anemia. Furthermore, the finding of similar extents of phosphatidylserine exposure by exogenous Ca2+-activated scrambling in both control erythrocytes and the patient’s erythrocytes implies that suppressed scramblase activity rather than flippase activity contributes to the maintenance of phosphatidylserine in the inner leaflet of human erythrocytes. PMID:26944472

  3. Translational characterization of [11C]GSK931145, a PET ligand for the glycine transporter type 1.

    PubMed

    Gunn, Roger N; Murthy, Venkatesha; Catafau, Ana M; Searle, Graham; Bullich, Santiago; Slifstein, Mark; Ouellet, Daniele; Zamuner, Stefano; Herance, Raul; Salinas, Cristian; Pardo-Lozano, Ricardo; Rabiner, Eugenii A; Farre, Magi; Laruelle, Marc

    2011-12-01

    The current interest in developing Glycine transporter Type 1 (GlyT-1) inhibitors, for diseases such as schizophrenia, has led to the demand for a GlyT-1 PET molecular imaging tool to aid drug development and dose selection. We report on [(11) C]GSK931145 as a novel GlyT-1 imaging probe in primate and man. Primate PET studies were performed to determine the level of specific binding following homologous competition with GSK931145 and the plasma-occupancy relationship of the GlyT-1 inhibitor GSK1018921. Human PET studies were performed to determine the test-retest reproducibility of [(11) C]GSK931145 and the plasma-occupancy relationship of GSK1018921. [(11) C]GSK931145 entered primate and human brain and yielded a heterogeneous pattern of uptake which was similar in both species with highest uptake in midbrain, thalamus, and cerebellum. Homologous competition in primates indicated no viable reference region and gave binding potential estimates between 1.5 and 3 for midbrain, thalamus and cerebellum, While the distribution and binding potential values were similar across species, both the plasma free fraction (f(P) : 0.8 vs. 8%) and delivery (K(1) : 0.025 vs. 0.126 ml cm(-3) min(-1) ) were significantly lower in humans. Test-retest reproducibility in humans calculated using a two tissue compartmental model was poor (VAR(V(T) ): 29-38%), but was improved using a pseudo reference tissue model (VAR(BP(ND) ): 16-23%). GSK1018921 EC(50) estimates were 22.5 and 45.7 ng/ml in primates and humans, respectively. PMID:21688322

  4. ATP11C is a major flippase in human erythrocytes and its defect causes congenital hemolytic anemia.

    PubMed

    Arashiki, Nobuto; Takakuwa, Yuichi; Mohandas, Narla; Hale, John; Yoshida, Kenichi; Ogura, Hiromi; Utsugisawa, Taiju; Ohga, Shouichi; Miyano, Satoru; Ogawa, Seishi; Kojima, Seiji; Kanno, Hitoshi

    2016-05-01

    Phosphatidylserine is localized exclusively to the inner leaflet of the membrane lipid bilayer of most cells, including erythrocytes. This asymmetric distribution is critical for the survival of erythrocytes in circulation since externalized phosphatidylserine is a phagocytic signal for splenic macrophages. Flippases are P-IV ATPase family proteins that actively transport phosphatidylserine from the outer to inner leaflet. It has not yet been determined which of the 14 members of this family of proteins is the flippase in human erythrocytes. Herein, we report that ATP11C encodes a major flippase in human erythrocytes, and a genetic mutation identified in a male patient caused congenital hemolytic anemia inherited as an X-linked recessive trait. Phosphatidylserine internalization in erythrocytes with the mutant ATP11C was decreased 10-fold compared to that of the control, functionally establishing that ATP11C is a major flippase in human erythrocytes. Contrary to our expectations phosphatidylserine was retained in the inner leaflet of the majority of mature erythrocytes from both controls and the patient, suggesting that phosphatidylserine cannot be externalized as long as scramblase is inactive. Phosphatidylserine-exposing cells were found only in the densest senescent cells (0.1% of total) in which scramblase was activated by increased Ca(2+) concentration: the percentage of these phosphatidylserine-exposing cells was increased in the patient's senescent cells accounting for his mild anemia. Furthermore, the finding of similar extents of phosphatidylserine exposure by exogenous Ca(2+)-activated scrambling in both control erythrocytes and the patient's erythrocytes implies that suppressed scramblase activity rather than flippase activity contributes to the maintenance of phosphatidylserine in the inner leaflet of human erythrocytes. PMID:26944472

  5. The use of /sup 11/C-glucose and positron emission tomography to measure brain glucose metabolism

    SciTech Connect

    Mintun, M.A.; Raichle, M.E.; Welch, M.J.; Kilbourn, M.R.

    1985-05-01

    To measure regional cerebral metabolism of glucose (CMRGlu) with positron emission tomography (PET), but avoid the potential problems inherent in the use of /sup 18/F-fluoro-deoxyglucose, (e.g. regional variation in regional rate constants and instability of the ''lumped constant''), the authors have developed a method using uniformly labeled /sup 11/C-glucose. The method employs a 4-compartment model that accounts for vascular tracer, transport of tracer in and out of the extravascular space, metabolism of tracer, and the production of labeled carbon dioxide, which is free to leave the tissue with blood flow. The differential equations for this model, when solved for CMRGlu, yield CMRGlu=k/sub 1/ . k/sub 3/ . CBF . C/sub B//(k/sub 1/ . k/sub 3/+CBF/CBV . (k/sub 2/+k/sub 3/)) where CBF and CBV are cerebral blood flow and volume, C/sub B/ is unlabeled blood glucose content, k/sub 1/ and k/sub 2/ are transport rate constants and k/sub 3/ is the metabolism rate constant. The authors have begun implementing this technique in baboons and human subjects by first measuring regional CBV and CBF with extant PET methods, then after injection of 20-40mCi of U-/sup 11/C-glucose, estimating the rate constants from 40 sequential PET scans taken over 20 minutes. Resulting white-to-gray matter range in CMRGlu for one typical human subject was 2.9 to 6.3 mg/(min . 100 mg). Oxygen metabolism (CMRO/sub 2/) was also measured at the same sitting with PET and the molar ratio of CMRO/sub 2//CMRGlu ranged from 5.8 to 6.4 as would be expected. These results demonstrate that it may be feasible to avoid the difficulties of an analogue tracer in the measurement of CMRGlu by using /sup 11/C-glucose.

  6. Rapid analysis for metabolites of 11C-labelled drugs: fate of [11C]-S-4-(tert.-butylamino-2-hydroxypropoxy)-benzimidazol-2-one in the dog.

    PubMed

    Jones, H A; Rhodes, C G; Law, M P; Becket, J M; Clark, J C; Boobis, A R; Taylor, G W

    1991-10-01

    Positron emission tomography (PET) requires the use of compounds labelled with short-lived, positron-emitting isotopes (e.g., t1/2 of 11C approximately 120 min). As the concentration of unbound, non-metabolised drug is required as the input function for modeling, this presents particular problems for the study of the kinetics and metabolism of such compounds. We have now developed a rapid extraction procedure, followed by high-performance liquid chromatography using a short analytical column coupled to an on-line gamma-detector to determine the metabolism and kinetics of a non-selective beta-adrenergic antagonist of high affinity, S-4-(tert.-butylamino-2-hydroxypropoxy)benzimidazol-2-one. This antagonist is potentially well suited to the non-invasive localisation of beta-receptors in vivo. The ligand was rapidly taken up into the beta-receptor pool or excreted in urine, with less than 5% of the drug converted to metabolites. Plasma protein binding was only 16%. No significant metabolism of the ligand was observed in the anaesthetised dog, and, therefore, no correction for blood metabolite concentration is required for kinetic analysis of the 11C-labelled ligand during PET studies in this species. The analytical method reported here should be widely applicable: quantification of metabolites enables accurate estimation of the input function and is critical to the interpretation of PET data. PMID:1686775

  7. Development of 1-N-(11)C-Methyl-L- and -D-Tryptophan for pharmacokinetic imaging of the immune checkpoint inhibitor 1-Methyl-Tryptophan.

    PubMed

    Xie, Lin; Maeda, Jun; Kumata, Katsushi; Yui, Joji; Zhang, Yiding; Hatori, Akiko; Nengaki, Nobuki; Wakizaka, Hidekatsu; Fujinaga, Masayuki; Yamasaki, Tomoteru; Shimoda, Yoko; Higuchi, Makoto; Suhara, Tetsuya; Wang, Feng; Zhang, Ming-Rong

    2015-01-01

    1-Methyl-tryptophan (1MTrp) is known as a specific inhibitor targeting the immune-checkpoint protein indoleamine-2,3-dioxygenase, in two stereoisomers of levorotary (L) and dextrorotary (D). A long-standing debate exists in immunology and oncology: which stereoisomer has the potential of antitumor immunotherapy. Herein, we developed two novel radioprobes, 1-N-(11)C-methyl-L- and -D-tryptophan ((11)C-L-1MTrp and (11)C-D-1MTrp), without modifying the chemical structures of the two isomers, and investigated their utility for pharmacokinetic imaging of the whole body. (11)C-L-1MTrp and (11)C-D-1MTrp were synthesized rapidly with radiochemical yields of 47 ± 6.3% (decay-corrected, based on (11)C-CO2), a radiochemical purity of >98%, specific activity of 47-130 GBq/μmol, and high enantiomeric purity. PET/CT imaging in rats revealed that for (11)C-L-1MTrp, the highest distribution of radioactivity was observed in the pancreas, while for (11)C-D-1MTrp, it was observed in the kidney. Ex vivo biodistribution confirmed the PET/CT results, indicating the differences in pharmacokinetics between the two isomers. Both (11)C-L-1MTrp and (11)C-D-1MTrp are therefore useful PET probes for delineating the distribution and action of the checkpoint inhibitor 1MTrp in vivo. This study represents the first step toward using whole-body and real-time insight to disentangle the antitumor potential of the two stereoisomers of 1MTrp, and it can facilitate the development of 1MTrp immunotherapy. PMID:26552594

  8. Development of 1-N-11C-Methyl-l- and -d-Tryptophan for pharmacokinetic imaging of the immune checkpoint inhibitor 1-Methyl-Tryptophan

    PubMed Central

    Xie, Lin; Maeda, Jun; Kumata, Katsushi; Yui, Joji; Zhang, Yiding; Hatori, Akiko; Nengaki, Nobuki; Wakizaka, Hidekatsu; Fujinaga, Masayuki; Yamasaki, Tomoteru; Shimoda, Yoko; Higuchi, Makoto; Suhara, Tetsuya; Wang, Feng; Zhang, Ming-Rong

    2015-01-01

    1-Methyl-tryptophan (1MTrp) is known as a specific inhibitor targeting the immune- checkpoint protein indoleamine-2,3-dioxygenase, in two stereoisomers of levorotary (l) and dextrorotary (d). A long-standing debate exists in immunology and oncology: which stereoisomer has the potential of antitumor immunotherapy. Herein, we developed two novel radioprobes, 1-N-11C-methyl-l- and -d-tryptophan (11C-l-1MTrp and 11C-d-1MTrp), without modifying the chemical structures of the two isomers, and investigated their utility for pharmacokinetic imaging of the whole body. 11C-l-1MTrp and 11C-d-1MTrp were synthesized rapidly with radiochemical yields of 47 ± 6.3% (decay-corrected, based on 11C-CO2), a radiochemical purity of >98%, specific activity of 47–130 GBq/μmol, and high enantiomeric purity. PET/CT imaging in rats revealed that for 11C-l-1MTrp, the highest distribution of radioactivity was observed in the pancreas, while for 11C-D-1MTrp, it was observed in the kidney. Ex vivo biodistribution confirmed the PET/CT results, indicating the differences in pharmacokinetics between the two isomers. Both 11C-l-1MTrp and 11C-d-1MTrp are therefore useful PET probes for delineating the distribution and action of the checkpoint inhibitor 1MTrp in vivo. This study represents the first step toward using whole-body and real-time insight to disentangle the antitumor potential of the two stereoisomers of 1MTrp, and it can facilitate the development of 1MTrp immunotherapy. PMID:26552594

  9. Range degradation and distal edge behavior of proton radiotherapy beams using 11C activation and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Elmekawy, Ahmed Farouk

    The distal edge of therapeutic proton radiation beams was investigated by different methods. Proton beams produced at the Hampton University Proton Therapy Institute (HUPTI) were used to irradiate a Polymethylmethacrylate (PMMA) phantom for three different ranges (13.5, 17.0 and 21.0 cm) to investigate the distal slope dependence of the Bragg peak. The activation of 11 C was studied by scanning the phantom less than 10 minutes post-irradiation with a Philips Big Bore Gemini(c) PET/CT. The DICOM images were imported into the Varian Eclipse(c) Treatment Planning System (TPS) for analysis and then analyzed by ImageJ(c) . The distal slope ranged from ?0.1671 +/- 0.0036 to -0.1986 +/- 0.0052 (pixel intensity/slice number) for ranges 13.5 to 21.0 cm respectively. A realistic description of the setup was modeled using the GATE 7.0 Monte Carlo simulation tool and compared to the experiment data. The results show the distal slope ranged from -0.1158+/-0.0133 to -0.0787+/-0.002 (Gy/mm). Additionally, low activity, 11C were simulated to study the 11C reconstructed half-life dependence versus the initial activity for six ranges chosen around the previous activation study. The results of the expected/nominal half-life vs. activity ranged from -5 x 10-4 +/- 2.8104 x 10-4 to 1.6 x 10-3 +/- 9.44 x 10-4 (%diff./Bq). The comparison between two experiments with proton beams on a PMMA phantom and multi-layer ion chamber, and two GATE simulations of a proton beam incident on a water phantom and 11C PET study show that: (i) the distal fall-off variation of the steepness of the slopes are found to be similar thus validating the sensitivity of the PET technique to the range degradation and (ii) the average of the super-ratios difference between all studies observed is primarily due to the difference in the dose deposited in the media.

  10. Build-Ups in the Supply Chain of the Brain: on the Neuroenergetic Cause of Obesity and Type 2 Diabetes Mellitus

    PubMed Central

    Peters, Achim; Langemann, Dirk

    2009-01-01

    Obesity and type 2 diabetes have become the major health problems in many industrialized countries. A few theoretical frameworks have been set up to derive the possible determinative cause of obesity. One concept views that food availability determines food intake, i.e. that obesity is the result of an external energy “push” into the body. Another one views that the energy milieu within the human organism determines food intake, i.e. that obesity is due to an excessive “pull” from inside the organism. Here we present the unconventional concept that a healthy organism is maintained by a “competent brain-pull” which serves systemic homeostasis, and that the underlying cause of obesity is “incompetent brain-pull”, i.e. that the brain is unable to properly demand glucose from the body. We describe the energy fluxes from the environment, through the body, towards the brain with a mathematical “supply chain” model and test whether its predictions fit medical and experimental data sets from our and other research groups. In this way, we show data-based support of our hypothesis, which states that under conditions of food abundance incompetent brain-pull will lead to build-ups in the supply chain culminating in obesity and type 2 diabetes. In the same way, we demonstrate support of the related hypothesis, which states that under conditions of food deprivation a competent brain-pull mechanism is indispensable for the continuance of the brain´s high energy level. In conclusion, we took the viewpoint of integrative physiology and provided evidence for the necessity of brain-pull mechanisms for the benefit of health. Along these lines, our work supports recent molecular findings from the field of neuroenergetics and continues the work on the “Selfish Brain” theory dealing with the maintenance of the cerebral and peripheral energy homeostasis. PMID:19584906

  11. Building-Up of a DNA Barcode Library for True Bugs (Insecta: Hemiptera: Heteroptera) of Germany Reveals Taxonomic Uncertainties and Surprises

    PubMed Central

    Raupach, Michael J.; Hendrich, Lars; Küchler, Stefan M.; Deister, Fabian; Morinière, Jérome; Gossner, Martin M.

    2014-01-01

    During the last few years, DNA barcoding has become an efficient method for the identification of species. In the case of insects, most published DNA barcoding studies focus on species of the Ephemeroptera, Trichoptera, Hymenoptera and especially Lepidoptera. In this study we test the efficiency of DNA barcoding for true bugs (Hemiptera: Heteroptera), an ecological and economical highly important as well as morphologically diverse insect taxon. As part of our study we analyzed DNA barcodes for 1742 specimens of 457 species, comprising 39 families of the Heteroptera. We found low nucleotide distances with a minimum pairwise K2P distance <2.2% within 21 species pairs (39 species). For ten of these species pairs (18 species), minimum pairwise distances were zero. In contrast to this, deep intraspecific sequence divergences with maximum pairwise distances >2.2% were detected for 16 traditionally recognized and valid species. With a successful identification rate of 91.5% (418 species) our study emphasizes the use of DNA barcodes for the identification of true bugs and represents an important step in building-up a comprehensive barcode library for true bugs in Germany and Central Europe as well. Our study also highlights the urgent necessity of taxonomic revisions for various taxa of the Heteroptera, with a special focus on various species of the Miridae. In this context we found evidence for on-going hybridization events within various taxonomically challenging genera (e.g. Nabis Latreille, 1802 (Nabidae), Lygus Hahn, 1833 (Miridae), Phytocoris Fallén, 1814 (Miridae)) as well as the putative existence of cryptic species (e.g. Aneurus avenius (Duffour, 1833) (Aradidae) or Orius niger (Wolff, 1811) (Anthocoridae)). PMID:25203616

  12. Investigations of heat transfer, entropy generation and pressure build up for upward flow in a vertical channel equipped with a fin array

    NASA Astrophysics Data System (ADS)

    Nemitallah, Medhat A.; Zohir, Alaa E.

    2015-11-01

    The optimal thermal systems design criteria by maximizing the amount of heat transfer per pressure losses is a very important topic. In this work, flow and convection and radiation heat transfer characteristics are studied numerically for a flow in a vertical channel equipped with transverse fin array. The influences of fin height on heat transfer characteristics and fluid flow is investigated. Large number of fins is used (40 fins) in order to reach the fully developed conditions after few fins from the entrance. Based on the calculated data of temperature and velocity, the local entropy generation is calculated through the whole channel by solving the entropy generation equation. The results are validated against the available data in the literature and both results are in a good agreement. Optimizations for flow conditions and channel geometry are performed in order to obtain maximum heat transfer per pumping power losses. The results showed that the highest values of total heat transfer per pumping power losses are obtained at fin height to the gap width values of 0.1 and 0.3. The effect of heat transfer by radiation on entropy generation is examined and, the effect of the ratio, Gr/Re2, on the pressure field is also investigated. It was found that a positive pressure gradient appears downstream in the channel when the value of Gr/Re2 exceeds a certain limit. For Gr/Re2 values between 0 and 9, the pressure gradient is negative; however, when the value Gr/Re2 exceeds 9, the pressure starts to build up through the channel axis.

  13. Changing nutrient stoichiometry affects phytoplankton production, DOP build up and dinitrogen fixation - a mesocosm experiment in the eastern tropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Löscher, C. R.; Neulinger, S. C.; Reichel, A. F.; Loginova, A.; Borchard, C.; Schmitz, R. A.; Hauss, H.; Kiko, R.; Riebesell, U.

    2015-07-01

    Ocean deoxygenation due to climate change may alter redox-sensitive nutrient cycles in the marine environment. The productive eastern tropical North Atlantic (ETNA) upwelling region may be particularly affected when the relatively moderate oxygen minimum zone (OMZ) deoxygenates further and microbially-driven nitrogen (N) loss processes are promoted. Consequently, water masses with a low N : P ratio could reach the euphotic layer, possibly influencing primary production in those waters. Previous mesocosm studies in the oligotrophic Atlantic Ocean identified N availability as controlling of primary production, while a possible co-limitation of nitrate and phosphate (P) could not be ruled out. To better understand the impact of changing N : P ratios on primary production and on N2 fixation in the ETNA surface ocean, we conducted land-based mesocosm experiments with natural plankton communities and applied a broad range of N : P ratios (2.67-48). Silicate was supplied at 15 μmol L-1 in all mesocosms. We monitored nutrient drawdown, bloom formation, biomass build up and diazotrophic feedback in response to variable nutrient stoichiometry. Our results confirmed N to be limiting to primary production. We found that excess P was channeled through particulate organic matter (POP) into the dissolved organic matter (DOP) pool. In mesocosms with low P availability, DOP was utilized while N2 fixation increased, suggesting a link between those two processes. Interestingly this observation was most pronounced in mesocosms where inorganic N was still available, indicating that bioavailable N does not necessarily has to have a negative impact on N2 fixation. We observed a shift from a mixed cyanobacterial/proteobacterial dominated active diazotrophic community towards diazotrophic diatom symbionts of the Richelia-Rhizosolenia symbiosis. We hypothesize that a potential change in nutrient stoichiometry in the ETNA might lead to a general shift within the diazotrophic community

  14. Application of Gray Markov SCGM(1,1)c Model to Prediction of Accidents Deaths in Coal Mining

    PubMed Central

    Lan, Jian-yi; Zhou, Ying

    2014-01-01

    The prediction of mine accident is the basis of aviation safety assessment and decision making. Gray prediction is suitable for such kinds of system objects with few data, short time, and little fluctuation, and Markov chain theory is just suitable for forecasting stochastic fluctuating dynamic process. Analyzing the coal mine accident human error cause, combining the advantages of both Gray prediction and Markov theory, an amended Gray Markov SCGM(1,1)c model is proposed. The gray SCGM(1,1)c model is applied to imitate the development tendency of the mine safety accident, and adopt the amended model to improve prediction accuracy, while Markov prediction is used to predict the fluctuation along the tendency. Finally, the new model is applied to forecast the mine safety accident deaths from 1990 to 2010 in China, and, 2011–2014 coal accidents deaths were predicted. The results show that the new model not only discovers the trend of the mine human error accident death toll but also overcomes the random fluctuation of data affecting precision. It possesses stronger engineering application.

  15. Orthorhombic 11C Pyrrhotite from Michałkowa, Góry Sowie Block, The Sudetes, Poland - Preliminary Report

    NASA Astrophysics Data System (ADS)

    Rybicki, Maciej; Krzykawski, Tomasz

    2014-09-01

    This study provides the preliminary report about first occurrence of orthorhombic 11C pyrrhotite (Fe(i-x)S) from the Sudetes, Poland. Samples of pyrrhotite-containing two-pyroxene gabbro were found in a classic pegmatite locality in Michałkowa near Walim in the Góry Sowie Block. Based on microscopic methods, pyrrhotite is associated with pentlandite, chalcopyrite, chromite, ilmenite, gersdorffite, magnetite, biotite, magnesiohornblende, clinochlore, lizardite and talc. X-Ray diffraction (XRD) indicate that pyrrhotite has orthorhombic 11C structure and it is characterized by: a = 3.433(9) Å, b = 5.99(2) Å, c = 5.7432(5) Å, ß = 90° and d 102 = 2.06906 Å. Mössbauer studies confirmed the XRD data. Pyrrhotite has three sextets with hyperfine parameter values 30.8 T for sextet A, 27.9 T and 25.8 T for sextets B and C respectively, indicating orthorhombic structure, the composition near Fe10S11 and x = 0.0909.

  16. Orthorhombic 11C pyrrhotite from Michałkowa, Góry Sowie Block, The Sudetes, Poland - preliminary report

    NASA Astrophysics Data System (ADS)

    Rybicki, Maciej; Krzykawski, Tomasz

    2014-09-01

    This study provides the preliminary report about first occurrence of orthorhombic 11C pyrrhotite (Fe(1-x)S) from the Sudetes, Poland. Samples of pyrrhotite-containing two-pyroxene gabbro were found in a classic pegmatite locality in Michałkowa near Walim in the Góry Sowie Block. Based on microscopic methods, pyrrhotite is associated with pentlandite, chalcopyrite, chromite, ilmenite, gersdorffite, magnetite, biotite, magnesiohornblende, clinochlore, lizardite and talc. X-Ray diffraction (XRD) indicate that pyrrhotite has orthorhombic 11C structure and it is characterized by: a = 3.433(9) Å, b = 5.99(2) Å, c = 5.7432(5) Å, β = 90º and d102 = 2.06906 Å. Mössbauer studies confirmed the XRD data. Pyrrhotite has three sextets with hyperfine parameter values 30.8 T for sextet A, 27.9 T and 25.8 T for sextets B and C respectively, indicating orthorhombic structure, the composition near Fe10S11 and x = 0.0909

  17. Structure of low-lying states of {sup 10,11}C from proton elastic and inelastic scattering

    SciTech Connect

    Jouanne, C.; Lapoux, V.; Auger, F.; Alamanos, N.; Drouart, A.; Gillibert, A.; Lobo, G.; Musumarra, A.; Nalpas, L.; Pollacco, E.; Sida, J.-L.; Trotta, M.; Blumenfeld, Y.; Khan, E.; Suomijaervi, T.; Zerguerras, T.; Roussel-Chomaz, P.; Savajols, H.; Lagoyannis, A.; Pakou, A.

    2005-07-01

    To probe the ground state and transition densities, elastic and inelastic scattering on a proton target were measured in inverse kinematics for the unstable {sup 10}C and {sup 11}C nuclei at 45.3 and 40.6 MeV/nucleon, respectively. The detection of the recoil proton was performed by the MUST telescope array, in coincidence with a wall of scintillators for the quasiprojectile. The differential cross sections for elastic and inelastic scattering to the first excited states are compared to the optical model calculations performed within the framework of the microscopic nucleon-nucleus Jeukenne-Lejeune-Mahaux potential. Elastic scattering is sensitive to the matter-root-mean square radius found to be 2.42{+-}0.1 and 2.33{+-}0.1 fm, for {sup 10,11}C, respectively. The transition densities from cluster and mean-field models are tested, and the cluster model predicts the correct order of magnitude of cross sections for the transitions of both isotopes. Using the Bohr-Mottelson prescription, a profile for the {sup 10}C transition density from the 0{sup +} ground to the 2{sub 1}{sup +} state is deduced from the data. The corresponding neutron transition matrix element is extracted: M{sub n}=5.51{+-}1.09 fm{sup 2}.

  18. Regional brain distribution of translocator protein using [(11)C]DPA-713 PET in individuals infected with HIV.

    PubMed

    Coughlin, Jennifer M; Wang, Yuchuan; Ma, Shuangchao; Yue, Chen; Kim, Pearl K; Adams, Ashley V; Roosa, Heidi V; Gage, Kenneth L; Stathis, Marigo; Rais, Rana; Rojas, Camilo; McGlothan, Jennifer L; Watkins, Crystal C; Sacktor, Ned; Guilarte, Tomas R; Zhou, Yun; Sawa, Akira; Slusher, Barbara S; Caffo, Brian; Kassiou, Michael; Endres, Christopher J; Pomper, Martin G

    2014-06-01

    Imaging the brain distribution of translocator protein (TSPO), a putative biomarker for glial cell activation and neuroinflammation, may inform management of individuals infected with HIV by uncovering regional abnormalities related to neurocognitive deficits and enable non-invasive therapeutic monitoring. Using the second-generation TSPO-targeted radiotracer, [(11)C]DPA-713, we conducted a positron emission tomography (PET) study to compare the brains of 12 healthy human subjects to those of 23 individuals with HIV who were effectively treated with combination antiretroviral therapy (cART). Compared to PET data from age-matched healthy control subjects, [(11)C]DPA-713 PET of individuals infected with HIV demonstrated significantly higher volume-of-distribution (VT) ratios in white matter, cingulate cortex, and supramarginal gyrus, relative to overall gray matter VT, suggesting localized glial cell activation in susceptible regions. Regional TSPO abnormalities were evident within a sub-cohort of neuro-asymptomatic HIV subjects, and an increase in the VT ratio within frontal cortex was specifically linked to individuals affected with HIV-associated dementia. These findings were enabled by employing a gray matter normalization approach for PET data quantification, which improved test-retest reproducibility, intra-class correlation within the healthy control cohort, and sensitivity of uncovering abnormal regional findings. PMID:24567030

  19. Fluence thresholds for grazing incidence hard x-ray mirrors

    SciTech Connect

    Aquila, A.; Ozkan, C.; Sinn, H.; Tschentscher, T.; Mancuso, A. P.; Gaudin, J.; Sobierajski, R.; Klepka, M. T.; Dłużewski, P.; Morawiec, K.; Störmer, M.; Bajt, S.; Ohashi, H.; Koyama, T.; Tono, K.; Inubushi, Y. [RIKEN and others

    2015-06-15

    X-ray Free Electron Lasers (XFELs) have the potential to contribute to many fields of science and to enable many new avenues of research, in large part due to their orders of magnitude higher peak brilliance than existing and future synchrotrons. To best exploit this peak brilliance, these XFEL beams need to be focused to appropriate spot sizes. However, the survivability of X-ray optical components in these intense, femtosecond radiation conditions is not guaranteed. As mirror optics are routinely used at XFEL facilities, a physical understanding of the interaction between intense X-ray pulses and grazing incidence X-ray optics is desirable. We conducted single shot damage threshold fluence measurements on grazing incidence X-ray optics, with coatings of ruthenium and boron carbide, at the SPring-8 Angstrom compact free electron laser facility using 7 and 12 keV photon energies. The damage threshold dose limits were found to be orders of magnitude higher than would naively be expected. The incorporation of energy transport and dissipation via keV level energetic photoelectrons accounts for the observed damage threshold.

  20. Reference Materials for Reactor Neutron Fluence Rate and Temperature Measurements

    NASA Astrophysics Data System (ADS)

    Ingelbrecht, C.

    2003-06-01

    Certified reference materials are distributed by the European Commission through the BCR® programme (over 500 CRMs) including a series of activation and fission monitor materials originally proposed by the Euratom Working Group on Reactor Dosimetry. The current range (18 CRMs) includes materials to cover the complete energy spectrum, and suitable for different irradiation times. Fission monitors are 238UO2 or 237NpO2 in the form of microspheres. Activation monitors are high purity metals (Ni, Cu, Al, Fe, Nb, Rh, or Ti), certified for interfering trace impurities, or dilute aluminium-based alloys. Reference materials newly certified are IRMM-530R A1-0.1%Au, replacing the exhausted IRMM-530 material, used as comparator for k0- standardisation, and three new Al-Co alloys (0.01, 0.1 and 1.0%Co). Others in the process of certification are A1-0.1%Ag and A1-2%Sc for thermal and epithermal fluence rate measurements and two uranium-doped glass materials intended for dosimetry by the fission-track technique. Various alloy compositions have been prepared for use as melt-wire temperature monitors with melting points ranging from 198 to 327ºC.

  1. The radial and longitudinal dependence of SEP intensities and fluences

    NASA Astrophysics Data System (ADS)

    Li, G.; Zank, G.; Verkhoglyadova, O.; Ruzmaikin, A.; Feynman, J.; Jun, I.

    Solar Energetic Particles SEPs are an important hazard in the context of space weather These particles bombard spacecraft and can cause instruments onboard to malfunction At sufficiently high energies and dosages they can also be extremely harmful to biological materials human bodies and are therefore one of the major safety concerns for the future manned spacecraft program We now know that these particles are associated with Coronal Mass Ejection CMEs driven shocks As a CME-driven shock propagates outward particles are injected and accelerated at the shock front via a first order Fermi mechanism aka diffusive shock acceleration After being accelerated the particles convect with the shock diffuse both upstream and downstream of the shock and many eventually escape the shock complex after reaching far upstream downstream In this work we present a model calculation of the SEP time intensity profile The model is based on a 2D-ZEUS MHD code which is used to simulate the solar wind The shock is modeled using a shell model where particle convection and diffusion are followed numerically When particles reach some distance ahead of the shock they are can escape from the shock Their subsequent motion is followed using a Monte-Carlo approach This sophisticated model allows us to obtain a time intensity profile and instantaneous particle spectra at various locations We will discuss the radial and longitudinal dependence of both the intensities and fluences

  2. Fluence-convolution broad-beam (FCBB) dose calculation.

    PubMed

    Lu, Weiguo; Chen, Mingli

    2010-12-01

    IMRT optimization requires a fast yet relatively accurate algorithm to calculate the iteration dose with small memory demand. In this paper, we present a dose calculation algorithm that approaches these goals. By decomposing the infinitesimal pencil beam (IPB) kernel into the central axis (CAX) component and lateral spread function (LSF) and taking the beam's eye view (BEV), we established a non-voxel and non-beamlet-based dose calculation formula. Both LSF and CAX are determined by a commissioning procedure using the collapsed-cone convolution/superposition (CCCS) method as the standard dose engine. The proposed dose calculation involves a 2D convolution of a fluence map with LSF followed by ray tracing based on the CAX lookup table with radiological distance and divergence correction, resulting in complexity of O(N(3)) both spatially and temporally. This simple algorithm is orders of magnitude faster than the CCCS method. Without pre-calculation of beamlets, its implementation is also orders of magnitude smaller than the conventional voxel-based beamlet-superposition (VBS) approach. We compared the presented algorithm with the CCCS method using simulated and clinical cases. The agreement was generally within 3% for a homogeneous phantom and 5% for heterogeneous and clinical cases. Combined with the 'adaptive full dose correction', the algorithm is well suitable for calculating the iteration dose during IMRT optimization. PMID:21081826

  3. N-11C-Methyl-Dopamine PET Imaging of Sympathetic Nerve Injury in a Swine Model of Acute Myocardial Ischemia: A Comparison with 13N-Ammonia PET

    PubMed Central

    Zhou, Weina; Wang, Xiangcheng; He, Yulin; Nie, Yongzhen; Zhang, Guojian; Wang, Cheng; Wang, Chunmei; Wang, Xuemei

    2016-01-01

    Objective. Using a swine model of acute myocardial ischemia, we sought to validate N-11C-methyl-dopamine (11C-MDA) as an agent capable of imaging cardiac sympathetic nerve injury. Methods. Acute myocardial ischemia was surgically generated in Chinese minipigs. ECG and serum enzyme levels were used to detect the presence of myocardial ischemia. Paired 11C-MDA PET and 13N-ammonia PET scans were performed at baseline, 1 day, and 1, 3, and 6 months after surgery to relate cardiac sympathetic nerve injury to blood perfusion. Results. Seven survived the surgical procedure. The ECG-ST segment was depressed, and levels of the serum enzymes increased. Cardiac uptake of tracer was quantified as the defect volume. Both before and immediately after surgery, the images obtained with 11C-MDA and 13N-ammonia were similar. At 1 to 6 months after surgery, however, 11C-MDA postsurgical left ventricular myocardial defect volume was significantly greater compared to 13N-ammonia. Conclusions. In the Chinese minipig model of acute myocardial ischemia, the extent of the myocardial defect as visualized by 11C-MDA is much greater than would be suggested by blood perfusion images, and the recovery from myocardial sympathetic nerve injury is much slower than the restoration of blood perfusion. 11C-MDA PET may provide additional biological information during recovery from ischemic heart disease. PMID:27034950

  4. Positron emission tomography ligand [11C]5-hydroxy-tryptophan can be used as a surrogate marker for the human endocrine pancreas.

    PubMed

    Eriksson, Olof; Espes, Daniel; Selvaraju, Ram K; Jansson, Emma; Antoni, Gunnar; Sörensen, Jens; Lubberink, Mark; Biglarnia, Ali-Reza; Eriksson, Jan W; Sundin, Anders; Ahlström, Håkan; Eriksson, Barbro; Johansson, Lars; Carlsson, Per-Ola; Korsgren, Olle

    2014-10-01

    In humans, a well-developed serotonin system is localized to the pancreatic islets while being absent in exocrine pancreas. Assessment of pancreatic serotonin biosynthesis could therefore be used to estimate the human endocrine pancreas. Proof of concept was tested in a prospective clinical trial by comparisons of type 1 diabetic (T1D) patients, with extensive reduction of β-cells, with healthy volunteers (HVs). C-peptide-negative (i.e., insulin-deficient) T1D subjects (n = 10) and HVs (n = 9) underwent dynamic positron emission tomography with the radiolabeled serotonin precursor [(11)C]5-hydroxy-tryptophan ([(11)C]5-HTP). A significant accumulation of [(11)C]5-HTP was obtained in the pancreas of the HVs, with large interindividual variation. A substantial and highly significant reduction (66%) in the pancreatic uptake of [(11)C]5-HTP in T1D subjects was observed, and this was most evident in the corpus and caudal regions of the pancreas where β-cells normally are the major constituent of the islets. [(11)C]5-HTP retention in the pancreas was reduced in T1D compared with nondiabetic subjects. Accumulation of [(11)C]5-HTP in the pancreas of both HVs and subjects with T1D was in agreement with previously reported morphological observations on the β-cell volume, implying that [(11)C]5-HTP retention is a useful noninvasive surrogate marker for the human endocrine pancreas. PMID:24848067

  5. Rapid radiosynthesis of [11C] and [14C]azelaic, suberic, and sebacic acids for in vivo mechanistic studies of systemic acquired resistance in plants

    SciTech Connect

    Best M.; Fowler J.; Best, M.; Gifford, A.N.; Kim, S.W.; Babst, B.; Piel, M.; Roesch, F.; Fowler, J.S.

    2011-11-25

    A recent report that the aliphatic dicarboxylic acid, azelaic acid (1,9-nonanedioic acid) but not related acids, suberic acid (1,8-octanedioic acid) or sebacic (1,10-decanedioic acid) acid induces systemic acquired resistance to invading pathogens in plants stimulated the development of a rapid method for labeling these dicarboxylic acids with {sup 11}C and {sup 14}C for in vivo mechanistic studies in whole plants. {sup 11}C-labeling was performed by reaction of ammonium [{sup 11}C]cyanide with the corresponding bromonitrile precursor followed by hydrolysis with aqueous sodium hydroxide solution. Total synthesis time was 60 min. Median decay-corrected radiochemical yield for [{sup 11}C]azelaic acid was 40% relative to trapped [{sup 11}C]cyanide, and specific activity was 15 GBq/{micro}mol. Yields for [{sup 11}C]suberic and sebacic acids were similar. The {sup 14}C-labeled version of azelaic acid was prepared from potassium [{sup 14}C]cyanide in 45% overall radiochemical yield. Radiolabeling procedures were verified using {sup 13}C-labeling coupled with {sup 13}C-NMR and liquid chromatography-mass spectrometry analysis. The {sup 11}C and {sup 14}C-labeled azelaic acid and related dicarboxylic acids are expected to be of value in understanding the mode-of-action, transport, and fate of this putative signaling molecule in plants.

  6. Space Environment Effects: Model for Emission of Solar Protons (ESP): Cumulative and Worst Case Event Fluences

    NASA Technical Reports Server (NTRS)

    Xapsos, M. A.; Barth, J. L.; Stassinopoulos, E. G.; Burke, E. A.; Gee, G. B.

    1999-01-01

    The effects that solar proton events have on microelectronics and solar arrays are important considerations for spacecraft in geostationary and polar orbits and for interplanetary missions. Designers of spacecraft and mission planners are required to assess the performance of microelectronic systems under a variety of conditions. A number of useful approaches exist for predicting information about solar proton event fluences and, to a lesser extent, peak fluxes. This includes the cumulative fluence over the course of a mission, the fluence of a worst-case event during a mission, the frequency distribution of event fluences, and the frequency distribution of large peak fluxes. Naval Research Laboratory (NRL) and NASA Goddard Space Flight Center, under the sponsorship of NASA's Space Environments and Effects (SEE) Program, have developed a new model for predicting cumulative solar proton fluences and worst-case solar proton events as functions of mission duration and user confidence level. This model is called the Emission of Solar Protons (ESP) model.

  7. Effect of fluence on carbon nanostructures produced by laser ablation in liquid nitrogen

    NASA Astrophysics Data System (ADS)

    Tabatabaie, Nushin; Dorranian, Davoud

    2016-05-01

    Effects of laser fluence on the properties of carbon nanostructures produced by laser ablation method in liquid nitrogen have been studied experimentally. The beam of a Q-switched Nd:YAG laser of 1064-nm wavelength at 7 ns pulse width and different fluences is employed to irradiate the graphite target in liquid nitrogen. Properties of carbon nanostructures were studied using their UV-Vis-NIR spectrum, TEM images, and Raman scattering spectrum. Two categories of graphene nanosheets and carbon nanoparticles were observed due to variation of laser fluence. Results show that in our experimental condition there is a threshold fluence for producing carbon nanoparticles. With increasing the laser fluence from the threshold, the amount of carbon nanoparticles in suspensions was increased, while the amount of graphene nanosheets was decreased.

  8. Using [(11)C]Ro15 4513 PET to characterise GABA-benzodiazepine receptors in opiate addiction: Similarities and differences with alcoholism.

    PubMed

    Lingford-Hughes, Anne; Myers, James; Watson, Ben; Reid, Alastair G; Kalk, Nicola; Feeney, Adrian; Hammers, Alexander; Riaño-Barros, Daniela A; McGinnity, Colm J; Taylor, Lindsay G; Rosso, Lula; Brooks, David J; Turkheimer, Federico; Nutt, David J

    2016-05-15

    The importance of the GABA-benzodiazepine receptor complex and its subtypes are increasingly recognised in addiction. Using the α1/α5 benzodiazepine receptor PET radioligand [(11)C]Ro15 4513, we previously showed reduced binding in the nucleus accumbens and hippocampus in abstinent alcohol dependence. We proposed that reduced [(11)C]Ro15 4513 binding in the nucleus accumbens was a marker of addiction whilst the reduction in hippocampus and positive relationship with memory was a consequence of chronic alcohol abuse. To examine this further we assessed [(11)C]Ro15 4513 binding in another addiction, opiate dependence, and used spectral analysis to estimate contributions of α1 and α5 subtypes to [(11)C]Ro15 4513 binding in opiate and previously acquired alcohol-dependent groups. Opiate substitute maintained opiate-dependent men (n=12) underwent an [(11)C]Ro15 4513 PET scan and compared with matched healthy controls (n=13). We found a significant reduction in [(11)C]Ro15 4513 binding in the nucleus accumbens in the opiate-dependent compared with the healthy control group. There was no relationship between [(11)C]Ro15 4513 binding in the hippocampus with memory. We found that reduced [(11)C]Ro15 4513 binding was associated with reduced α5 but not α1 subtypes in the opiate-dependent group. This was also seen in an alcohol-dependent group where an association between memory performance and [(11)C]Ro15 4513 binding was primarily driven by α5 and not α1 subtype. We suggest that reduced α5 levels in the nucleus accumbens are associated with addiction since we have now shown this in dependence to two pharmacologically different substances, alcohol and opiates. PMID:26876472

  9. Sp1 binds two sites in the CD11c promoter in vivo specifically in myeloid cells and cooperates with AP1 to activate transcription.

    PubMed Central

    Noti, J D; Reinemann, B C; Petrus, M N

    1996-01-01

    The leukocyte integrin gene, CD11c, is transcriptionally regulated and is expressed predominantly on differentiated cells of the myelomonocytic lineage. In this study we have demonstrated that the regions -72 to -63 and -132 to -104 of the CD11c promoter contain elements responsible for phorbol ester-induced differentiation of the myeloid cell line HL60. DNase I footprinting analysis revealed that these regions can bind purified Sp1, and supershift analysis with Sp1 antibody confirmed that Sp1 in HL60 nuclear extracts could bind these regions. Transfection analysis of CD11c promoter-chloramphenicol acetyltransferase constructs containing deletions of these Sp1-binding sites revealed that these sites are essential for expression of the CD11c gene in HL60 cells but not in the T-cell line Molt4 or the cervical carcinoma cell line HeLa. Moreover, cotransfection of pPacSp1 along with these CD11c promoter-chloramphenicol acetyltransferase constructs into Sp1-deficient Drosophila Schneider 2 cells verified that these sites are essential for Sp1-dependent expression of the CD11c promoter. In vivo genomic footprinting revealed that Sp1 contacts the CD11c promoter within the regions -69 to -63 and -116 to -105 in phorbol 12-myristate 13-acetate-differentiated HL60 cells but not in undifferentiated HL60 cells or in Molt4 or HeLa cells. Cotransfection assays in HL60 cells revealed that Sp1 acts synergistically with Ap1 to activate CD11c. Further, both Sp1 sites are capable of cooperating with AP1. In vitro DNase I footprinting analysis with purified Sp1 and c-jun proteins showed that Sp1 binding could facilitate binding of c-jun. We propose that myeloid-specific expression of the CD11c promoter and is facilitated by cooperative interaction between the Sp1- and Ap1-binding sites. PMID:8649405

  10. A two-compartment description and kinetic procedure for measuring regional cerebral ( sup 11 C)nomifensine uptake using positron emission tomography

    SciTech Connect

    Salmon, E.; Brooks, D.J.; Leenders, K.L.; Turton, D.R.; Hume, S.P.; Cremer, J.E.; Jones, T.; Frackowiak, R.S. )

    1990-05-01

    S-(11C)Nomifensine (S-(11C)NMF) is a positron-emitting tracer suitable for positron emission tomography, which binds to both dopaminergic and noradrenergic reuptake sites in the striatum and the thalamus. Modelling of the cerebral distribution of this drug has been hampered by the rapid appearance of glucuronide metabolites in the plasma, which do not cross the blood--brain barrier. To date, (11C)NMF uptake has simply been expressed as regional versus nonspecific cerebellar activity ratios. We have calculated a free NMF input curve from red cell activity curves, using the fact that the free drug rapidly equilibrates between red cells and plasma, while glucuronides do not enter red cells. With this free (11C)NMF input function, all regional cerebral uptake curves could be fitted to a conventional two-compartment model, defining tracer distribution in terms of (11C)NMF regional volume of distribution. Assuming that the cerebellar volume of distribution of (11C)NMF represents the nonspecific volume of distribution of the tracer in striatum and thalamus, we have calculated an equilibrium partition coefficient for (11C)NMF between freely exchanging specific and nonspecific compartments in these regions, representing its binding potential to dopaminergic or noradrenergic uptake sites (or complexes). This partition coefficient was lower in the striatum when the racemate rather than the active S-enantiomer of (11C)NMF was administered. In the striatum of patients suffering from Parkinson's disease and multiple-system atrophy, the specific compartmentation of S-(11C)NMF was significantly decreased compared with that of age-matched volunteers.

  11. Using [11C]Ro15 4513 PET to characterise GABA-benzodiazepine receptors in opiate addiction: Similarities and differences with alcoholism

    PubMed Central

    Lingford-Hughes, Anne; Myers, James; Watson, Ben; Reid, Alastair G.; Kalk, Nicola; Feeney, Adrian; Hammers, Alexander; Riaño-Barros, Daniela A.; McGinnity, Colm J.; Taylor, Lindsay G.; Rosso, Lula; Brooks, David J.; Turkheimer, Federico; Nutt, David J.

    2016-01-01

    The importance of the GABA-benzodiazepine receptor complex and its subtypes are increasingly recognised in addiction. Using the α1/α5 benzodiazepine receptor PET radioligand [11C]Ro15 4513, we previously showed reduced binding in the nucleus accumbens and hippocampus in abstinent alcohol dependence. We proposed that reduced [11C]Ro15 4513 binding in the nucleus accumbens was a marker of addiction whilst the reduction in hippocampus and positive relationship with memory was a consequence of chronic alcohol abuse. To examine this further we assessed [11C]Ro15 4513 binding in another addiction, opiate dependence, and used spectral analysis to estimate contributions of α1 and α5 subtypes to [11C]Ro15 4513 binding in opiate and previously acquired alcohol-dependent groups. Opiate substitute maintained opiate-dependent men (n = 12) underwent an [11C]Ro15 4513 PET scan and compared with matched healthy controls (n = 13). We found a significant reduction in [11C]Ro15 4513 binding in the nucleus accumbens in the opiate-dependent compared with the healthy control group. There was no relationship between [11C]Ro15 4513 binding in the hippocampus with memory. We found that reduced [11C]Ro15 4513 binding was associated with reduced α5 but not α1 subtypes in the opiate-dependent group. This was also seen in an alcohol-dependent group where an association between memory performance and [11C]Ro15 4513 binding was primarily driven by α5 and not α1 subtype. We suggest that reduced α5 levels in the nucleus accumbens are associated with addiction since we have now shown this in dependence to two pharmacologically different substances, alcohol and opiates. PMID:26876472

  12. Materials International Space Station Experiment-6 (MISSE-6) Atomic Oxygen Fluence Monitor Experiment

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Miller, Sharon K.; Waters, Deborah L.

    2010-01-01

    An atomic oxygen fluence monitor was flown as part of the Materials International Space Station Experiment-6 (MISSE-6). The monitor was designed to measure the accumulation of atomic oxygen fluence with time as it impinged upon the ram surface of the MISSE 6B Passive Experiment Container (PEC). This was an active experiment for which data was to be stored on a battery-powered data logger for post-flight retrieval and analysis. The atomic oxygen fluence measurement was accomplished by allowing atomic oxygen to erode two opposing wedges of pyrolytic graphite that partially covered a photodiode. As the wedges of pyrolytic graphite erode, the area of the photodiode that is illuminated by the Sun increases. The short circuit current, which is proportional to the area of illumination, was to be measured and recorded as a function of time. The short circuit current from a different photodiode, which was oriented in the same direction and had an unobstructed view of the Sun, was also to be recorded as a reference current. The ratio of the two separate recorded currents should bear a linear relationship with the accumulated atomic oxygen fluence and be independent of the intensity of solar illumination. Ground hyperthermal atomic oxygen exposure facilities were used to evaluate the linearity of the ratio of short circuit current to the atomic oxygen fluence. In flight, the current measurement circuitry failed to operate properly, thus the overall atomic oxygen mission fluence could only be estimated based on the physical erosion of the pyrolytic graphite wedges. The atomic oxygen fluence was calculated based on the knowledge of the space atomic oxygen erosion yield of pyrolytic graphite measured from samples on the MISSE 2. The atomic oxygen fluence monitor, the expected result and comparison of mission atomic oxygen fluence based on the erosion of the pyrolytic graphite and Kapton H atomic oxygen fluence witness samples are presented in this paper.

  13. Dependence of the phototropic response of Arabidopsis thaliana on fluence rate and wavelength

    PubMed Central

    Konjević, Radomir; Steinitz, Benjamin; Poff, Kenneth L.

    1989-01-01

    In the phototropic response of Arabidopsis thaliana seedlings, the shape of the fluence-response relation depends on fluence rate and wavelength. At low fluence rates, the response to 450-nm light is characterized by a single maximum at about 0.3 μmol·m-2. At higher fluence rates, the response shows two distinct maxima, I and II, at 0.3 and 3.5 μmol·m-2, respectively. The response to 500-nm light shows a single maximum at 2 μmol·m-2, and the response to 510-nm light shows a single maximum at 4.5 μmol·m-2, independent of fluence rate. The response to 490-nm light shows a maximal at 4.5 μmol·m-2 and a shoulder at about 0.6 μmol·m-2. Preirradiation with high-fluence 510-nm light from above, immediately followed by unilateral 450-nm light, eliminates maximum II but not maximum I. Preirradiation with high-fluence 450-nm light from above eliminates the response to subsequent unilateral irradiation with either 450-nm or 510-nm light. The recovery of the response following high-fluence 450-nm light is considerably slower than the recovery following high-fluence 510-nm light. Unilateral irradiation with low-fluence 510-nm light followed by 450-nm light results in curvature that is approximately the sum of those produced by either irradiation alone. Based on these results, it is proposed that phototropism in A. thaliana seedlings is mediated by at least two blue-light photoreceptor pigments. PMID:16594094

  14. Intensity Modulated Radiation Therapy Dose Painting for Localized Prostate Cancer Using {sup 11}C-choline Positron Emission Tomography Scans

    SciTech Connect

    Chang, Joe H.; Lim Joon, Daryl; Lee, Sze Ting; Gong, Sylvia J.; Anderson, Nigel J.; Scott, Andrew M.; Davis, Ian D.; Clouston, David; Bolton, Damien; Hamilton, Christopher S.; Khoo, Vincent

    2012-08-01

    Purpose: To demonstrate the technical feasibility of intensity modulated radiation therapy (IMRT) dose painting using {sup 11}C-choline positron emission tomography PET scans in patients with localized prostate cancer. Methods and Materials: This was an RT planning study of 8 patients with prostate cancer who had {sup 11}C-choline PET scans prior to radical prostatectomy. Two contours were semiautomatically generated on the basis of the PET scans for each patient: 60% and 70% of the maximum standardized uptake values (SUV{sub 60%} and SUV{sub 70%}). Three IMRT plans were generated for each patient: PLAN{sub 78}, which consisted of whole-prostate radiation therapy to 78 Gy; PLAN{sub 78-90}, which consisted of whole-prostate RT to 78 Gy, a boost to the SUV{sub 60%} to 84 Gy, and a further boost to the SUV{sub 70%} to 90 Gy; and PLAN{sub 72-90}, which consisted of whole-prostate RT to 72 Gy, a boost to the SUV{sub 60%} to 84 Gy, and a further boost to the SUV{sub 70%} to 90 Gy. The feasibility of these plans was judged by their ability to reach prescription doses while adhering to published dose constraints. Tumor control probabilities based on PET scan-defined volumes (TCP{sub PET}) and on prostatectomy-defined volumes (TCP{sub path}), and rectal normal tissue complication probabilities (NTCP) were compared between the plans. Results: All plans for all patients reached prescription doses while adhering to dose constraints. TCP{sub PET} values for PLAN{sub 78}, PLAN{sub 78-90}, and PLAN{sub 72-90} were 65%, 97%, and 96%, respectively. TCP{sub path} values were 71%, 97%, and 89%, respectively. Both PLAN{sub 78-90} and PLAN{sub 72-90} had significantly higher TCP{sub PET} (P=.002 and .001) and TCP{sub path} (P<.001 and .014) values than PLAN{sub 78}. PLAN{sub 78-90} and PLAN{sub 72-90} were not significantly different in terms of TCP{sub PET} or TCP{sub path}. There were no significant differences in rectal NTCPs between the 3 plans. Conclusions: IMRT dose painting for

  15. Brain Regional α-[11C]Methyl-L-Tryptophan Trapping in Medication-Free Patients With Obsessive-Compulsive Disorder

    PubMed Central

    Berney, Alexandre; Leyton, Marco; Gravel, Paul; Sibon, Igor; Sookman, Debbie; Neto, Pedro Rosa; Diksic, Mirko; Nakai, Akio; Pinard, Gilbert; Todorov, Christo; Okazawa, Hidehiko; Blier, Pierre; Nordahl, Thomas Edward; Benkelfat, Chawki

    2013-01-01

    Context The hypothesis of a serotonin (5-hydroxytryptamine [5-HT]) dysfunction in obsessive-compulsive disorder (OCD) stems largely from the clinical efficacy of 5-HT reuptake inhibitors. Serotonergic abnormalities in the unmedicated symptomatic state, however, remain to be fully characterized. Objective To investigate brain regional 5-HT synthesis, as indexed by positron emission tomography and the α-[11C]methyl-L-tryptophan trapping constant (K*), in treatment-free adults meeting criteria for OCD. Design Between-group comparison. Setting Department of Psychiatry and Montreal Neurological Institute, McGill University, and Department of Psychology, McGill University Health Centre, Quebec, Canada. Participants Twenty-one medication-free patients with OCD (15 men with a mean [SD] age of 33.2 [9.3] years and 6 women with a mean [SD] age of 35.8 [7.1] years) and 21 healthy controls matched for age and sex (15 men with a mean [SD] age of 32.9 [10.1] years and 6 women with a mean [SD] age of 36.5.5 [8.6] years). Main Outcome Measure The α-[11C]methyl-L-tryptophan brain trapping constant K*, which was analyzed with Statistical Parametric Mapping (SPM8) and with proportional normalization (extent threshold of 100 voxels with a peak threshold of P≤.005). Results Compared with healthy controls, the patients with OCD exhibited significantly greater α-[11C]methyl-L-tryptophan trapping in the right hippocampus and left temporal gyrus (Brodmann area 20). In the larger sub-sample of all men, these same differences were also evident, as well as higher K* values in the caudate nucleus. Individual differences in symptom severity correlated positively with K* values sampled from the caudate and temporal lobe of the patients with OCD, respectively. There were no regions where the patients exhibited abnormally low K* values. Volumetric analyses found no morphometric alterations that would account for the group differences. Conclusion The results support previous reports of greater

  16. An assessment of fracture resistance of three composite resin core build-up materials on three prefabricated non-metallic posts, cemented in endodontically treated teeth: an in vitro study

    PubMed Central

    Pal, Bhupinder; Pujari, Prashant

    2015-01-01

    Endodontically treated teeth with excessive loss of tooth structure would require to be restored with post and core to enhance the strength and durability of the tooth and to achieve retention for the restoration. The non-metallic posts have a superior aesthetic quality. Various core build-up materials can be used to build-up cores on the posts placed in endodontically treated teeth. These materials would show variation in their bonding with the non-metallic posts thus affecting the strength and resistance to fracture of the remaining tooth structure. Aims. The aim of the study was to assess the fracture resistance of three composite resin core build-up materials on three prefabricated non-metallic posts, cemented in extracted endodontically treated teeth. Material and Methods. Forty-five freshly extracted maxillary central incisors of approximately of the same size and shape were selected for the study. They were divided randomly into 3 groups of 15 each, depending on the types of non-metallic posts used. Each group was further divided into 3 groups (A, B and C) of 5 samples each depending on three core build-up material used. Student’s unpaired ‘t’ test was also used to analyse and compare each group with the other groups individually, and decide whether their comparisons were statistically significant. Results. Luxacore showed the highest fracture resistance among the three core build-up materials with all the three posts systems. Ti-core had intermediate values of fracture resistance and Lumiglass had the least values of fracture resistance. PMID:25755926

  17. Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent

    PubMed Central

    COTES, Caroline; CARDOSO, Mayra; de MELO, Renata Marques; VALANDRO, Luiz Felipe; BOTTINO, Marco Antonio

    2015-01-01

    Objective The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement. Material and Methods Eighty blocks (8×8×4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO2 particles, silane application; (AO) Sandblasting with 50 mm Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath) and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05). Results The µTBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling. Conclusion Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement. PMID:25760269

  18. Thermal and structural properties of low-fluence irradiated graphite

    NASA Astrophysics Data System (ADS)

    Lexa, Dusan; Dauke, Michael

    2009-02-01

    The release of Wigner energy from graphite irradiated by fast neutrons at a TRIGA Mark II research reactor has been studied by differential scanning calorimetry and simultaneous differential scanning calorimetry / synchrotron powder X-ray diffraction between 25 and 725 °C at a heating rate of 10 °C min -1. The graphite, having been subject to a fast-neutron fluence from 5.67 × 10 20 to 1.13 × 10 22 n m -2 at a fast-neutron flux ( E > 0.1 MeV) of 7.88 × 10 16 n m -2 s -1 and at temperatures not exceeding 100 °C, exhibits Wigner energies ranging from 1.2 to 21.8 J g -1 and a Wigner energy accumulation rate of 1.9 × 10 -21 J g -1 n -1 m 2. The differential-scanning-calorimeter curves exhibit, in addition to the well known peak at ˜200 °C, a pronounced fine structure consisting of additional peaks at ˜150, ˜230, and ˜280 °C. These peaks correspond to activation energies of 1.31, 1.47, 1.57, and 1.72 eV, respectively. Crystal structure of the samples is intact. The dependence of the c lattice parameter on temperature between 25 and 725 °C as determined by Rietveld refinement leads to the expected microscopic thermal expansion coefficient along the c axis of ˜26 × 10 -6 °C -1. At 200 °C, coinciding with the maximum in the differential-scanning-calorimeter curves, no measurable changes in the rate of thermal expansion have been detected - unlike its decrease previously seen in more highly irradiated graphite.

  19. Ultra-fast fluence optimization for beam angle selection algorithms

    NASA Astrophysics Data System (ADS)

    Bangert, M.; Ziegenhein, P.; Oelfke, U.

    2014-03-01

    Beam angle selection (BAS) including fluence optimization (FO) is among the most extensive computational tasks in radiotherapy. Precomputed dose influence data (DID) of all considered beam orientations (up to 100 GB for complex cases) has to be handled in the main memory and repeated FOs are required for different beam ensembles. In this paper, the authors describe concepts accelerating FO for BAS algorithms using off-the-shelf multiprocessor workstations. The FO runtime is not dominated by the arithmetic load of the CPUs but by the transportation of DID from the RAM to the CPUs. On multiprocessor workstations, however, the speed of data transportation from the main memory to the CPUs is non-uniform across the RAM; every CPU has a dedicated memory location (node) with minimum access time. We apply a thread node binding strategy to ensure that CPUs only access DID from their preferred node. Ideal load balancing for arbitrary beam ensembles is guaranteed by distributing the DID of every candidate beam equally to all nodes. Furthermore we use a custom sorting scheme of the DID to minimize the overall data transportation. The framework is implemented on an AMD Opteron workstation. One FO iteration comprising dose, objective function, and gradient calculation takes between 0.010 s (9 beams, skull, 0.23 GB DID) and 0.070 s (9 beams, abdomen, 1.50 GB DID). Our overall FO time is < 1 s for small cases, larger cases take ~ 4 s. BAS runs including FOs for 1000 different beam ensembles take ~ 15-70 min, depending on the treatment site. This enables an efficient clinical evaluation of different BAS algorithms.

  20. [Detection of tumors in the central zone of the prostate with 11C-Choline PET/CT].

    PubMed

    Garcia, J R; Soler, M; Moragas, M; Ponce, A; Moreno, C; Riera, E

    2014-01-01

    Prostate tumors originate 68% in the peripheral region and 24% in the transitional region where tumors originating in the central zone are rare (8%). However, diagnosis of the tumors in the central zone is important since they exhibit greater aggressiveness conditioned by their location and different biological behavior. Magnetic resonance imaging shows problems in identifying lesions in the central prostate zone, since this region has a heterogeneous signal, mainly after the primary treatment. Ultrasound guided sextant biopsy shows a negative result in 28% of prostate tumors. Therefore, it is advisable to repeat or even to perform saturation biopsies. We present two patients, one of them with suspected biochemical prostate cancer and one with biochemical recurrence after radical treatment. In both, (11)C-Choline PET/CT allowed detection of the tumor focus in the central zone of the prostate, with negative complementary diagnostic test and biopsies. PMID:24119550

  1. [Radiosynthesis and preliminary evaluation of 5-([11C]methyloxy)-L-tryptophan as PET tumor imaging].

    PubMed

    He, Shan-zhen; Wang, Shu-xia; Hu, Kong-zhen; Yao, Bao-guo; Tang, Gang-hua

    2015-05-01

    The PET tracer 5-([11C]methyloxy)-L-tryptophan (5-(11)CMTP) was prepared by nucleophilic fluorination and alkylation reaction via a two-step procedure in order to develop specific tumor probe. The biodistribution and microPET imaging of 5-(11)CMTP were executed. The results unveiled that the overall radiochemical yield with no decay correction was (14.6 ±7.2) %, the radiochemical purity was more than 95% and high uptake and long retention time of 5-(11)CMTP in liver, kidney and blood were observed but low uptake in brain and muscle were found, furthermore, high uptake of 5-(11)CMTP in tumor tissue was observed. It seems that 5-(11)CMTP will be a potential amino acid tracer for tumors imaging with PET. PMID:26234137

  2. Muscarinic Receptor Occupancy and Cognitive Impairment: A PET Study with [11C](+)3-MPB and Scopolamine in Conscious Monkeys

    PubMed Central

    Yamamoto, Shigeyuki; Nishiyama, Shingo; Kawamata, Masahiro; Ohba, Hiroyuki; Wakuda, Tomoyasu; Takei, Nori; Tsukada, Hideo; Domino, Edward F

    2011-01-01

    The muscarinic cholinergic receptor (mAChR) antagonist scopolamine was used to induce transient cognitive impairment in monkeys trained in a delayed matching to sample task. The temporal relationship between the occupancy level of central mAChRs and cognitive impairment was determined. Three conscious monkeys (Macaca mulatta) were subjected to positron emission tomography (PET) scans with the mAChR radioligand N-[11C]methyl-3-piperidyl benzilate ([11C](+)3-MPB). The scan sequence was pre-, 2, 6, 24, and 48 h post-intramuscular administration of scopolamine in doses of 0.01 and 0.03 mg/kg. Occupancy levels of mAChR were maximal 2 h post-scopolamine in cortical regions innervated primarily by the basal forebrain, thalamus, and brainstem, showing that mAChR occupancy levels were 43–59 and 65–89% in doses of 0.01 and 0.03 mg/kg, respectively. In addition, dose-dependent impairment of working memory performance was measured 2 h after scopolamine. A positive correlation between the mAChR occupancy and cognitive impairment 2 and 6 h post-scopolamine was the greatest in the brainstem (P<0.00001). Although cognitive impairment was not observed 24 h post-scopolamine, sustained mAChR occupancy (11–24%) was found with both doses in the basal forebrain and thalamus, but not in the brainstem. These results indicate that a significant degree of mAChRs occupancy is needed to produce cognitive impairment by scopolamine. Furthermore, the importance of the brainstem cholinergic system in working memory in monkey is described. PMID:21430646

  3. Synthesis and Preclinical Evaluation of Sulfonamido-based [11C-Carbonyl]-Carbamates and Ureas for Imaging Monoacylglycerol Lipase

    PubMed Central

    Wang, Lu; Mori, Wakana; Cheng, Ran; Yui, Joji; Hatori, Akiko; Ma, Longle; Zhang, Yiding; Rotstein, Benjamin H.; Fujinaga, Masayuki; Shimoda, Yoko; Yamasaki, Tomoteru; Xie, Lin; Nagai, Yuji; Minamimoto, Takafumi; Higuchi, Makoto; Vasdev, Neil; Zhang, Ming-Rong; Liang, Steven H.

    2016-01-01

    Monoacylglycerol lipase (MAGL) is a 33 kDa member of the serine hydrolase superfamily that preferentially degrades 2-arachidonoylglycerol (2-AG) to arachidonic acid in the endocannabinoid system. Inhibition of MAGL is not only of interest for probing the cannabinoid pathway but also as a therapeutic and diagnostic target for neuroinflammation. Limited attempts have been made to image MAGL in vivo and a suitable PET ligand for this target has yet to be identified and is urgently sought to guide small molecule drug development in this pathway. Herein we synthesized and evaluated the physiochemical properties of an array of eleven sulfonamido-based carbamates and ureas with a series of terminal aryl moieties, linkers and leaving groups. The most potent compounds were a novel MAGL inhibitor, N-((1-(1H-1,2,4-triazole-1-carbonyl)piperidin-4-yl) methyl)-4-chlorobenzenesulfonamide (TZPU; IC50 = 35.9 nM), and the known inhibitor 1,1,1,3,3,3-hexafluoropropan-2-yl 4-(((4-chlorophenyl)sulfonamido) methyl)piperidine-1-carboxylate (SAR127303; IC50 = 39.3 nM), which were also shown to be selective for MAGL over fatty acid amide hydrolase (FAAH), and cannabinoid receptors (CB1 & CB2). Both of these compounds were radiolabeled with carbon-11 via [11C]COCl2, followed by comprehensive ex vivo biodistribution and in vivo PET imaging studies in normal rats to determine their brain permeability, specificity, clearance and metabolism. Whereas TZPU did not show adequate specificity to warrant further evaluation, [11C]SAR127303 was advanced for preliminary PET neuroimaging studies in nonhuman primate. The tracer showed good brain permeability (ca. 1 SUV) and heterogeneous regional brain distribution which is consistent with the distribution of MAGL. PMID:27279908

  4. D-(U-11C)glucose uptake and metabolism in the brain of insulin-dependent diabetic subjects

    SciTech Connect

    Gutniak, M.; Blomqvist, G.; Widen, L.; Stone-Elander, S.; Hamberger, B.; Grill, V. )

    1990-05-01

    We used D-(U-11C)glucose to evaluate transport and metabolism of glucose in the brain in eight nondiabetic and six insulin-dependent diabetes mellitus (IDDM) subjects. IDDM subjects were treated by continuous subcutaneous insulin infusion. Blood glucose was regulated by a Biostator-controlled glucose infusion during a constant insulin infusion. D-(U-11C)-glucose was injected for positron emission tomography studies during normoglycemia as well as during moderate hypoglycemia (arterial plasma glucose 2.74 +/- 0.14 in nondiabetic and 2.80 +/- 0.26 mmol/l (means +/- SE) in IDDM subjects). Levels of free insulin were constant and similar in both groups. The tracer data were analyzed using a three-compartment model with a fixed correction for 11CO2 egression. During normoglycemia the influx rate constant (k1) and blood-brain glucose flux did not differ between the two groups. During hypoglycemia k1 increased significantly and similarly in both groups (from 0.061 +/- 0.007 to 0.090 +/- 0.006 in nondiabetic and from 0.061 +/- 0.006 to 0.093 +/- 0.013 ml.g-1.min-1 in IDDM subjects). During normoglycemia the tracer-calculated metabolism of glucose was higher in the whole brain in the nondiabetic than in the diabetic subjects (22.0 +/- 1.9 vs. 15.6 +/- 1.1 mumol.100 g-1.min-1, P less than 0.01). During hypoglycemia tracer-calculated metabolism was decreased by 40% in nondiabetic subjects and by 28% in diabetic subjects. The results indicate that uptake of glucose is normal, but some aspect of glucose metabolism is abnormal in a group of well-controlled IDDM subjects.

  5. Decreased Norepinephrine Transporter Availability in Obesity: Positron Emission Tomography Imaging with (S,S)-[11C]O-Methylreboxetine

    PubMed Central

    Li, Chiang-shan R.; Potenza, Marc N.; Lee, Dianne E.; Planeta, Beata; Gallezot, Jean-Dominique; Labaree, David; Henry, Shannan; Nabulsi, Nabeel; Sinha, Rajita; Ding, Yu-Shin; Carson, Richard E.; Neumeister, Alexander

    2013-01-01

    Objectives Noradrenergic dysfunction is implicated in obesity. The norepinephrine transporter (NET) regulates the synaptic availability of norepinephrine. However, NET availability has not been previously characterized in vivo in obese people using Positron Emission Tomography (PET) imaging. Here we report findings evaluating NET availability in individuals with obesity and matched lean (i.e., normal weight) comparison subjects. Methods Seventeen obese but otherwise healthy individuals with a mean±SD body mass index (BMI) of 34.7±2.6 and 17 lean individuals with a mean±SD BMI of 23.1±1.4 were studied using a High-Resolution Research Tomograph (HRRT) and (S,S)-[11C]O-methylreboxetine ([11C]-MRB), a radioligand selective for the NET. The regional brain NET binding potential (BPND) was estimated by the multilinear reference tissue model 2 (MRTM2) with the occipital cortex as a reference region. BPND for regions of interest were obtained with the Automated Anatomic Labeling (AAL) template registered to individual’s structural MR scans. Results Obese individuals had lower NET BPND values in the thalamus (p<0.038, 27% reduction) including within the pulvinar (p<0.083, 30% reduction), but not in the hypothalamus, locus coeruleus or the raphe nuclei, compared to lean individuals. When age was included as a covariate, the difference in NET BPND values remained significant in the thalamus (p<0.025) and pulvinar (p<0.042). Conclusions These results indicate that NET availability is decreased in the thalamus, including the pulvinar, in obese individuals. These findings further support data indicating noradrenergic dysfunction in obesity and suggest impaired NE clearance in obesity. PMID:24121204

  6. Multidiagnostics analysis of ion dynamics in ultrafast laser ablation of metals over a large fluence range

    SciTech Connect

    Anoop, K. K.; Polek, M. P.; Bruzzese, R.; Amoruso, S.; Harilal, Sivanandan S.

    2015-02-28

    The ions dynamics in ultrafast laser ablation of metals is studied over a fluence range spanning from the ablation threshold up to ~75 J/cm2 by means of three established diagnostic techniques. Langmuir probe, Faraday cup and spectrally resolved ICCD imaging simultaneously monitor the laser-produced plasma ions produced during ultrafast laser ablation of a copper target. The fluence dependence of ion yield is analyzed observing the occurrence of three different regimes. Moreover, the specific ion yield shows a maximum at about 4-5 J/cm2, followed by a gradual reduction and a transition to a high-fluence regime above ~50 J/cm2. The fluence variation of the copper ions angular distribution is also analyzed, observing a gradual increase of forward peaking of Cu ions for fluences up to ~10 J/cm2. Then, a broader ion component is observed at larger angles for fluences larger than ~10 J/cm2. Finally, an experimental characterization of the ions angular distribution for several metallic targets (Mg, Al, Cr, Fe, Cu, and W) is carried out at a relatively high fluence of ~66 J/cm2. Interestingly, the ion emission from the volatile metals show a narrow forward peaked distribution and a high peak ion yield compared to the refractory metals. Moreover, the width of ion angular distributions presents a striking correlation with the peak ion yield.

  7. Direct measurement of the {sup 11}C({alpha},p){sup 14}N reaction at CRIB: A path from pp-chain to CNO

    SciTech Connect

    Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, D. N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.; Wanajo, S.

    2012-11-20

    We determined the total reaction rate of the {sup 11}C({alpha},p){sup 14}N reaction relevant to the nucleosynthesis in explosive hydrogen-burning stars. The measurement was performed by means of the thick target method in inverse kinematics with {sup 11}C RI beams. We performed the identification of the ground-state transition and excited-state transitions using time-of-flight information for the first time.

  8. Direct measurement of the breakout reaction {sup 11}C({alpha},p){sup 14}N in explosive hydrogen-burning process

    SciTech Connect

    Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, Dam N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.; Wanajo, S.

    2012-11-12

    We determined the {sup 11}C({alpha},p){sup 14}N reaction rate relevant to the nucleosynthesis in explosive hydrogen-burning stars. The measurement was performed by means of the thick target method in inverse kinematics with {sup 11}C RI beams. We derived the excitation functions for the ground-state transition and excited-state transitions using time-of-flight information for the first time. The present reaction rate is compared to the previous one.

  9. Characterisation of the contribution of the GABA-benzodiazepine α1 receptor subtype to [11C]Ro15-4513 PET images

    PubMed Central

    Myers, James FM; Rosso, Lula; Watson, Ben J; Wilson, Sue J; Kalk, Nicola J; Clementi, Nicoletta; Brooks, David J; Nutt, David J; Turkheimer, Federico E; Lingford-Hughes, Anne R

    2012-01-01

    This positron emission tomography (PET) study aimed to further define selectivity of [11C]Ro15-4513 binding to the GABARα5 relative to the GABARα1 benzodiazepine receptor subtype. The impact of zolpidem, a GABARα1-selective agonist, on [11C]Ro15-4513, which shows selectivity for GABARα5, and the nonselective benzodiazepine ligand [11C]flumazenil binding was assessed in humans. Compartmental modelling of the kinetics of [11C]Ro15-4513 time-activity curves was used to describe distribution volume (VT) differences in regions populated by different GABA receptor subtypes. Those with low α5 were best fitted by one-tissue compartment models; and those with high α5 required a more complex model. The heterogeneity between brain regions suggested spectral analysis as a more appropriate method to quantify binding as it does not a priori specify compartments. Spectral analysis revealed that zolpidem caused a significant VT decrease (∼10%) in [11C]flumazenil, but no decrease in [11C]Ro15-4513 binding. Further analysis of [11C]Ro15-4513 kinetics revealed additional frequency components present in regions containing both α1 and α5 subtypes compared with those containing only α1. Zolpidem reduced one component (mean±s.d.: 71%±41%), presumed to reflect α1-subtype binding, but not another (13%±22%), presumed to reflect α5. The proposed method for [11C]Ro15-4513 analysis may allow more accurate selective binding assays and estimation of drug occupancy for other nonselective ligands. PMID:22214903

  10. Building up analgesia in humans via the endogenous μ-opioid system by combining placebo and active tDCS: a preliminary report.

    PubMed

    DosSantos, Marcos F; Martikainen, Ilkka K; Nascimento, Thiago D; Love, Tiffany M; DeBoer, Misty D; Schambra, Heidi M; Bikson, Marom; Zubieta, Jon-Kar; DaSilva, Alexandre F

    2014-01-01

    Transcranial Direct Current Stimulation (tDCS) is a method of non-invasive brain stimulation that has been frequently used in experimental and clinical pain studies. However, the molecular mechanisms underlying tDCS-mediated pain control, and most important its placebo component, are not completely established. In this pilot study, we investigated in vivo the involvement of the endogenous μ-opioid system in the global tDCS-analgesia experience. Nine healthy volunteers went through positron emission tomography (PET) scans with [11C]carfentanil, a selective μ-opioid receptor (MOR) radiotracer, to measure the central MOR activity during tDCS in vivo (non-displaceable binding potential, BPND)--one of the main analgesic mechanisms in the brain. Placebo and real anodal primary motor cortex (M1/2mA) tDCS were delivered sequentially for 20 minutes each during the PET scan. The initial placebo tDCS phase induced a decrease in MOR BPND in the periaqueductal gray matter (PAG), precuneus, and thalamus, indicating activation of endogenous μ-opioid neurotransmission, even before the active tDCS. The subsequent real tDCS also induced MOR activation in the PAG and precuneus, which were positively correlated to the changes observed with placebo tDCS. Nonetheless, real tDCS had an additional MOR activation in the left prefrontal cortex. Although significant changes in the MOR BPND occurred with both placebo and real tDCS, significant analgesic effects, measured by improvements in the heat and cold pain thresholds, were only observed after real tDCS, not the placebo tDCS. This study gives preliminary evidence that the analgesic effects reported with M1-tDCS, can be in part related to the recruitment of the same endogenous MOR mechanisms induced by placebo, and that such effects can be purposely optimized by real tDCS. PMID:25029273

  11. Confirmation of fenfluramine effect on 5-HT1B receptor binding of [11C]AZ10419369 using an equilibrium approach

    PubMed Central

    Finnema, Sjoerd J; Varrone, Andrea; Hwang, Tzung-Jeng; Halldin, Christer; Farde, Lars

    2012-01-01

    Assessment of serotonin release in the living brain with positron emission tomography (PET) may have been hampered by the lack of suitable radioligands. We previously reported that fenfluramine caused a dose-dependent reduction in specific binding in monkeys using a classical displacement paradigm with bolus administration of [11C]AZ10419369. The aim of this study was to confirm our previous findings using an equilibrium approach in monkey. A total of 24 PET measurements were conducted using a bolus infusion protocol of [11C]AZ10419369 in three cynomolgus monkeys. Initial PET measurements were performed to assess suitable Kbol values. The fenfluramine effect on [11C]AZ10419369 binding was evaluated in a displacement and pretreatment paradigm. The effect of fenfluramine on [11C]AZ10419369 binding potential (BPND) was dose-dependent in the displacement paradigm and confirmed in the pretreatment paradigm. After pretreatment administration of fenfluramine (5.0 mg/kg), the mean BPND of the occipital cortex decreased by 39%, from 1.38±0.04 to 0.84±0.09. This study confirms that the new 5-HT1B receptor radioligand [11C]AZ10419369 is sensitive to fenfluramine-induced changes in endogenous serotonin levels in vivo. The more advanced methodology is suitable for exploring the sensitivity limit to serotonin release as measured using [11C]AZ10419369 and PET. PMID:22167236

  12. Increase of 20-HETE synthase after brain ischemia in rats revealed by PET study with 11C-labeled 20-HETE synthase-specific inhibitor

    PubMed Central

    Kawasaki, Toshiyuki; Marumo, Toshiyuki; Shirakami, Keiko; Mori, Tomoko; Doi, Hisashi; Suzuki, Masaaki; Watanabe, Yasuyoshi; Chaki, Shigeyuki; Nakazato, Atsuro; Ago, Yukio; Hashimoto, Hitoshi; Matsuda, Toshio; Baba, Akemichi; Onoe, Hirotaka

    2012-01-01

    20-Hydroxyeicosatetraenoic acid (20-HETE), an arachidonic acid metabolite known to be produced after cerebral ischemia, has been implicated in ischemic and reperfusion injury by mediating vasoconstriction. To develop a positron emission tomography (PET) probe for 20-HETE synthase imaging, which might be useful for monitoring vasoconstrictive processes in patients with brain ischemia, we synthesized a 11C-labeled specific 20-HETE synthase inhibitor, N′(4-dimethylaminohexyloxy)phenyl imidazole ([11C]TROA). Autoradiographic study showed that [11C]TROA has high-specific binding in the kidney and liver consistent with the previously reported distribution of 20-HETE synthase. Using transient middle cerebral artery occlusion in rats, PET study showed significant increases in the binding of [11C]TROA in the ipsilateral hemisphere of rat brains after 7 and 10 days, which was blocked by co-injection of excess amounts of TROA (10 mg/kg). The increased [11C]TROA binding on the ipsilateral side returned to basal levels within 14 days. In addition, quantitative real-time PCR revealed that increased expression of 20-HETE synthase was only shown on the ipsilateral side on day 7. These results indicate that [11C]TROA might be a useful PET probe for imaging of 20-HETE synthase in patients with cerebral ischemia. PMID:22669478

  13. A microPET comparison of the effects of etifoxine and diazepam on [(11)C]flumazenil uptake in rat brains.

    PubMed

    Bouillot, Caroline; Bonnefoi, Frédéric; Liger, François; Zimmer, Luc

    2016-01-26

    Using positron emission tomography (PET), the present study assessed the binding of [(11)C]flumazenil to GABA-A receptors in anesthetized rats following a single intravenous injection of an active dose of either etifoxine (25mg/kg) or diazepam (1mg/kg), which are both anxiolytic drugs. [(11)C]flumazenil binding was measured in five discrete brain structures, namely the caudate putamen, hippocampus, cerebellum, occipital cortex and parietal cortex. As expected, diazepam injection produced a significant decrease in [(11)C]flumazenil binding, which was interpreted as benzodiazepine GABA-A receptor occupancy, whereas etifoxine increased the binding of [(11)C]flumazenil. This first use of in vivo imaging after etifoxine administration revealed the activated binding pattern of [(11)C]flumazenil and highlighted the pharmacological differences between etifoxine and benzodiazepines. Using the same [(11)C]flumazenil radiotracer, PET neuroimaging could be applied to larger animals and, ultimately, to human subjects, thus providing new perspectives for better defining the molecular pharmacology of etifoxine. PMID:26644334

  14. Kinetic modeling of 11C-LY2795050, a novel antagonist radiotracer for PET imaging of the kappa opioid receptor in humans

    PubMed Central

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

    2014-01-01

    11C-LY2795050 is a novel kappa opioid receptor (KOR) antagonist tracer for positron emission tomography (PET) imaging. The purpose of this first-in-human study was to determine the optimal kinetic model for analysis of 11C-LY2795050 imaging data. Sixteen subjects underwent baseline scans and blocking scans after oral naltrexone. Compartmental modeling and multilinear analysis-1 (MA1) were applied using the arterial input functions. Two-tissue compartment model and MA1 were found to be the best models to provide reliable measures of binding parameters. The rank order of 11C-LY2795050 distribution volume (VT) matched the known regional KOR densities in the human brain. Blocking scans with naltrexone indicated no ideal reference region for 11C-LY2795050. Three methods for calculation of the nondisplaceable distribution volume (VND) were assessed: (1) individual VND estimated from naltrexone occupancy plots, (2) mean VND across subjects, and (3) a fixed fraction of cerebellum VT. Approach (3) produced the lowest intersubject variability in the calculation of binding potentials (BPND, BPF, and BPP). Therefore, binding potentials of 11C-LY2795050 can be determined if the specific binding fraction in the cerebellum is presumed to be unchanged by diseases and experimental conditions. In conclusion, results from the present study show the suitability of 11C-LY2795050 to image and quantify KOR in humans. PMID:25182664

  15. Kinetic modeling of (11)C-LY2795050, a novel antagonist radiotracer for PET imaging of the kappa opioid receptor in humans.

    PubMed

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

    2014-11-01

    (11)C-LY2795050 is a novel kappa opioid receptor (KOR) antagonist tracer for positron emission tomography (PET) imaging. The purpose of this first-in-human study was to determine the optimal kinetic model for analysis of (11)C-LY2795050 imaging data. Sixteen subjects underwent baseline scans and blocking scans after oral naltrexone. Compartmental modeling and multilinear analysis-1 (MA1) were applied using the arterial input functions. Two-tissue compartment model and MA1 were found to be the best models to provide reliable measures of binding parameters. The rank order of (11)C-LY2795050 distribution volume (VT) matched the known regional KOR densities in the human brain. Blocking scans with naltrexone indicated no ideal reference region for (11)C-LY2795050. Three methods for calculation of the nondisplaceable distribution volume (VND) were assessed: (1) individual VND estimated from naltrexone occupancy plots, (2) mean VND across subjects, and (3) a fixed fraction of cerebellum VT. Approach (3) produced the lowest intersubject variability in the calculation of binding potentials (BPND, BPF, and BPP). Therefore, binding potentials of (11)C-LY2795050 can be determined if the specific binding fraction in the cerebellum is presumed to be unchanged by diseases and experimental conditions. In conclusion, results from the present study show the suitability of (11)C-LY2795050 to image and quantify KOR in humans. PMID:25182664

  16. Neutron fluence vessel assessment in the 1300 MWe NPP French fleet: the FLUOLE program in EOLE

    SciTech Connect

    Blaise, P.; Thiollay, N.; Fougeras, P.; Destouches, C.; Beretz, D.; Pont, T.; Garnier, D.

    2006-07-01

    The Vessel Neutron fluence assessment is a key parameter for vessel embrittlement determination and plant lifetime estimation To validate this parameters, the CEA and its Industrial Partner EdF have decided to launch a devoted experimental program in the EOLE facility of the Cadarache Research Centre The aim of this proposed FLUOLE experimental program (acronym of Fluence in EOLE) is to provide the most accurate neutron propagation measurements in representative PWR neutron spectrum material and geometry in order to enable a reduction of uncertainties on calculated vessel fluence with Monte-Carlo codes such as MCNP or TRIPOLI. (authors)

  17. Review of the Palisades pressure vessel accumulated fluence estimate and of the least squares methodology employed

    SciTech Connect

    Griffin, P.J.

    1998-05-01

    This report provides a review of the Palisades submittal to the Nuclear Regulatory Commission requesting endorsement of their accumulated neutron fluence estimates based on a least squares adjustment methodology. This review highlights some minor issues in the applied methodology and provides some recommendations for future work. The overall conclusion is that the Palisades fluence estimation methodology provides a reasonable approach to a {open_quotes}best estimate{close_quotes} of the accumulated pressure vessel neutron fluence and is consistent with the state-of-the-art analysis as detailed in community consensus ASTM standards.

  18. Neutron fluence and energy reproducibility of a 2-dollar TRIGA reactor Pulse

    SciTech Connect

    Payne, Rosara F.; Drader, Jessica A.; Friese, Judah I.; Greenwood, Lawrence R.; Hines, Corey C.; Metz, Lori A.; Kephart, Jeremy D.; King, Matthew D.; Pierson, Bruce D.; Smith, Jeremy D.; Wall, Donald E.

    2009-10-01

    Washington State University’s 1 MW TRIGA reactor has a long history of utilization for neutron activation analysis (NAA). TRIGA reactors have the ability to pulse, reach supercritical (k>1) for short bursts of time. At this high power and fast time the energy spectrum and neutron fluence are largely uncharacterized. The pulse neutron energy spectrum and fluence were determined by the activation of Cu, Au, Co, Fe, and Ti. These analyses were completed with and without Cd shielding to determine reproducibility between pulses. The applications and implications of the neutron energy and fluence reproducibility to the use of pulsed NAA will be discussed.

  19. Radial fast-neutron fluence gradients during rotating 40Ar/39Ar sample irradiation recorded with metallic fluence monitors and geological age standards

    NASA Astrophysics Data System (ADS)

    Rutte, Daniel; Pfänder, Jörg A.; Koleška, Michal; Jonckheere, Raymond; Unterricker, Sepp

    2015-01-01

    the neutron-irradiation parameter J is one of the major uncertainties in 40Ar/39Ar dating. The associated uncertainty of the individual J-value for a sample of unknown age depends on the accuracy of the age of the geological standards, the fast-neutron fluence distribution in the reactor, and the distances between standards and samples during irradiation. While it is generally assumed that rotating irradiation evens out radial neutron fluence gradients, we observed axial and radial variations of the J-values in sample irradiations in the rotating channels of two reactors. To quantify them, we included three-dimensionally distributed metallic fast (Ni) and thermal- (Co) neutron fluence monitors in three irradiations and geological age standards in three more. Two irradiations were carried out under Cd shielding in the FRG1 reactor in Geesthacht, Germany, and four without Cd shielding in the LVR-15 reactor in Řež, Czech Republic. The 58Ni(nf,p)58Co activation reaction and γ-spectrometry of the 811 keV peak associated with the subsequent decay of 58Co to 58Fe allow one to calculate the fast-neutron fluence. The fast-neutron fluences at known positions in the irradiation container correlate with the J-values determined by mass-spectrometric 40Ar/39Ar measurements of the geological age standards. Radial neutron fluence gradients are up to 1.8 %/cm in FRG1 and up to 2.2 %/cm in LVR-15; the corresponding axial gradients are up to 5.9 and 2.1 %/cm. We conclude that sample rotation might not always suffice to meet the needs of high-precision dating and gradient monitoring can be crucial.

  20. Advanced [18F]FDG and [11C]flumazenil PET analysis for individual outcome prediction after temporal lobe epilepsy surgery for hippocampal sclerosis

    PubMed Central

    Yankam Njiwa, J.; Gray, K.R.; Costes, N.; Mauguiere, F.; Ryvlin, P.; Hammers, A.

    2014-01-01

    Purpose We have previously shown that an imaging marker, increased periventricular [11C]flumazenil ([11C]FMZ) binding, is associated with failure to become seizure free (SF) after surgery for temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS). Here, we investigated whether increased preoperative periventricular white matter (WM) signal can be detected on clinical [18F]FDG-PET images. We then explored the potential of periventricular FDG WM increases, as well as whole-brain [11C]FMZ and [18F]FDG images analysed with random forest classifiers, for predicting surgery outcome. Methods Sixteen patients with MRI-defined HS had preoperative [18F]FDG and [11C]FMZ-PET. Fifty controls had [18F]FDG-PET (30), [11C]FMZ-PET (41), or both (21). Periventricular WM signal was analysed using Statistical Parametric Mapping (SPM8), and whole-brain image classification was performed using random forests implemented in R (http://www.r-project.org). Surgery outcome was predicted at the group and individual levels. Results At the group level, non-seizure free (NSF) versus SF patients had periventricular increases with both tracers. Against controls, NSF patients showed more prominent periventricular [11C]FMZ and [18F]FDG signal increases than SF patients. All differences were more marked for [11C]FMZ. For individuals, periventricular WM signal increases were seen at optimized thresholds in 5/8 NSF patients for both tracers. For SF patients, 1/8 showed periventricular signal increases for [11C]FMZ, and 4/8 for [18F]FDG. Hence, [18F]FDG had relatively poor sensitivity and specificity. Random forest classification accurately identified 7/8 SF and 7/8 NSF patients using [11C]FMZ images, but only 4/8 SF and 6/8 NSF patients with [18F]FDG. Conclusion This study extends the association between periventricular WM increases and NSF outcome to clinical [18F]FDG-PET, but only at the group level. Whole-brain random forest classification increases [11C]FMZ-PET's performance for predicting

  1. Microdialysis with radiometric monitoring of L-[β-11C]DOPA to assess dopaminergic metabolism: effect of inhibitors of L-amino acid decarboxylase, monoamine oxidase, and catechol-O-methyltransferase on rat striatal dialysate.

    PubMed

    Okada, Maki; Nakao, Ryuji; Hosoi, Rie; Zhang, Ming-Rong; Fukumura, Toshimitsu; Suzuki, Kazutoshi; Inoue, Osamu

    2011-01-01

    The catecholamine, dopamine (DA), is synthesized from 3,4-dihydroxy-L-phenylalanine (L-DOPA) by aromatic L-amino acid decarboxylase (AADC). Dopamine metabolism is regulated by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT). To measure dopaminergic metabolism, we used microdialysis with radiometric detection to monitor L-[β-(11)C]DOPA metabolites in the extracellular space of the rat striatum. We also evaluated the effects of AADC, MAO, and COMT inhibitors on metabolite profiles. The major early species measured after administration of L-[β-(11)C]DOPA were [(11)C]3,4-dihydroxyphenylacetic acid ([(11)C]DOPAC) and [(11)C]homovanillic acid ([(11)C]HVA) in a 1:1 ratio, which shifted toward [(11)C]HVA with time. An AADC inhibitor increased the uptake of L-[β-(11)C]DOPA and L-3-O-methyl-[(11)C]DOPA and delayed the accumulation of [(11)C]DOPAC and [(11)C]HVA. The MAO and COMT inhibitors increased the production of [(11)C]3-methoxytyramine and [(11)C]DOPAC, respectively. These results reflect the L-DOPA metabolic pathway, suggesting that this method may be useful for assessing dopaminergic metabolism. PMID:20407462

  2. Plasma focus ion beam fluence and flux—For various gases

    SciTech Connect

    Lee, S.; Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148; Physics Department, University of Malaya ; Saw, S. H.; Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone 3148

    2013-06-15

    A recent paper derived benchmarks for deuteron beam fluence and flux in a plasma focus (PF) [S. Lee and S. H. Saw, Phys. Plasmas 19, 112703 (2012)]. In the present work we start from first principles, derive the flux equation of the ion beam of any gas; link to the Lee Model code and hence compute the ion beam properties of the PF. The results show that, for a given PF, the fluence, flux, ion number and ion current decrease from the lightest to the heaviest gas except for trend-breaking higher values for Ar fluence and flux. The energy fluence, energy flux, power flow, and damage factors are relatively constant from H{sub 2} to N{sub 2} but increase for Ne, Ar, Kr and Xe due to radiative cooling and collapse effects. This paper provides much needed benchmark reference values and scaling trends for ion beams of a PF operated in any gas.

  3. Light fluence normalization in turbid tissues via temporally unmixed multispectral optoacoustic tomography.

    PubMed

    Deán-Ben, X Luís; Stiel, Andre C; Jiang, Yuanyuan; Ntziachristos, Vasilis; Westmeyer, Gil G; Razansky, Daniel

    2015-10-15

    Discerning the accurate distribution of chromophores and biomarkers by means of optoacoustic imaging is commonly challenged by the highly heterogeneous excitation light patterns resulting from strong spatial variations of tissue scattering and absorption. Here we used the light-fluence dependent switching kinetics of reversibly switchable fluorescent proteins (RSFPs), in combination with real-time acquisition of volumetric multi-spectral optoacoustic data to correct for the light fluence distribution deep in scattering media. The new approach allows for dynamic fluence correction in time-resolved imaging, e.g., of moving organs, and can be extended to work with a large palette of available synthetic and genetically encoded photochromic substances for multiplexed wavelength-specific fluence normalization. PMID:26469596

  4. Effects of Laser Wavelength and Fluence in Pulsed Laser Deposition of Ge Films

    SciTech Connect

    Yap, Seong Shan; Reenaas, Turid Worren; Siew, Wee Ong; Tou, Teck Yong; Ladam, Cecile

    2011-03-30

    Nanosecond lasers with ultra-violet, visible and infrared wavelengths: KrF (248 nm, 25 ns) and Nd:YAG (1064 nm, 532 nm, 355 nm, 5 ns) were used to ablate polycrystalline Ge target and deposit Ge films in vacuum (<10-6 Torr). Time-integrated optical emission spectra were obtained for laser fluence from 0.5-10 J/cm{sup 2}. Neutrals and ionized Ge species in the plasma plume were detected by optical emission spectroscopy. Ge neutrals dominated the plasma plume at low laser fluence while Ge{sup +} ions above some threshold fluence. The deposited amorphous thin-film samples consisted of particulates of size from nano to micron. The relation of the film properties and plume species at different laser fluence and wavelengths were discussed.

  5. Rate of F center formation in sapphire under low-energy low-fluence Ar+ irradiation

    NASA Astrophysics Data System (ADS)

    Epie, E. N.; Wijesundera, D. N.; Tilakaratne, B. P.; Chen, Q. Y.; Chu, W. K.

    2016-03-01

    Ionoluminescence, optical absorption spectroscopy and Rutherford backscattering spectrometry channelling (RBS-C) have been used to study the rate of F center formation with fluence in 170 keV Ar+ irradiated single crystals of α-Al2O3 (sapphire) at room temperature. Implantation fluences range between 1013 cm-2 and 5 ×1014 cm-2. F center density (NF) has been found to display an initial rapid linear increase with Ar+ fluence followed by saturation to a maximum value of 1.74 ×1015 cm-2. Experimental results show a 1-1 correlation between radiation damage in the oxygen sublattice and F center density. This suggest F center kinetics in sapphire under low-energy low-fluence Ar irradiation is a direct consequence of dynamic competition between oxygen defect creation and recombination. An attempt has also been made to extend this discussion to F center kinetics in sapphire under swift heavy ion irradiation.

  6. Pressure-vessel-damage fluence reduction by low-leakage fuel management. [PWR

    SciTech Connect

    Cokinos, D.; Aronson, A.L.; Carew, J.F.; Kohut, P.; Todosow, M.; Lois, L.

    1983-01-01

    As a result of neutron-induced radiation damage to the pressure vessel and of an increased concern that in a PWR transient the pressure vessel may be subjected to pressurized thermal shock (PTS), detailed analyses have been undertaken to determine the levels of neutron fluence accumulation at the pressure vessels of selected PWR's. In addition, various methods intended to limit vessel damage by reducing the vessel fluence have been investigated. This paper presents results of the fluence analysis and the evaluation of the low-leakage fuel management fluence reduction method. The calculations were performed with DOT-3.5 in an octant of the core/shield/vessel configuration using a 120 x 43 (r, theta) mesh structure.

  7. Multicompartmental analysis of (/sup 11/C)-carfentanil binding to opiate receptors in humans measured by positron emission tomography

    SciTech Connect

    Frost, J.J.; Douglass, K.H.; Mayberg, H.S.; Dannals, R.F.; Links, J.M.; Wilson, A.A.; Ravert, H.T.; Crozier, W.C.; Wagner, H.N. Jr.

    1989-06-01

    (11C)-Carfentanil is a high affinity opiate agonist that can be used to localize mu opiate receptors in humans by positron emission tomography (PET). A four-compartment model was used to obtain quantitative estimates of rate constants for receptor association and dissociation. PET studies were performed in five normal subjects in the absence and presence of 1 mg/kg naloxone. Arterial plasma concentration of (11C)-carfentanil and its labeled metabolites were determined during each PET study. The value of k3/k4 = Bmax/kD was determined for each subject in the presence and absence of naloxone. There was a significant reduction in the value of k3/k4 from 3.4 +/- 0.92 to 0.26 +/- 0.13 in the thalamus (p less than 0.01) and from 1.8 +/- 0.33 to 0.16 +/- 0.065 in the frontal cortex (p less than 0.001). Mean values of frontal cortex/occipital cortex and thalamus/occipital cortex ratios were determined for the interval 35-70 min after injection when receptor binding is high relative to nonspecific binding. The relationship between the measured region/occipital cortex values and the corresponding values of k3/k4 in the presence and absence of naloxone was: regions/occipital cortex = 0.95 + 0.74 (k3/k4) with r = 0.98 (n = 20). Simulation studies also demonstrated a linear relationship between the thalamus/occipital cortex or frontal cortex/occipital cortex ratio and k3/k4 for less than twofold increases or decreases in k3/k4. Simulation studies in which thalamic blood flow was varied demonstrated no significant effect on the region/occipital cortex ratio at 35-70 min for a twofold increase or fourfold decrease in blood flow. Therefore, the region/occipital cortex ratio can be used to quantitate changes in k3/k4 when tracer kinetic modeling is not feasible.

  8. Evaluation of [11C]MRB for assessment of occupancy of norepinephrine transporters: Studies with atomoxetine in non-human primates

    PubMed Central

    Gallezot, Jean-Dominique; Weinzimmer, David; Nabulsi, Nabeel; Lin, Shu-Fei; Fowles, Krista; Sandiego, Christine; McCarthy, Timothy J.; Maguire, R. Paul; Carson, Richard E.; Ding, Yu-Shin

    2013-01-01

    [11C]MRB is one of the most promising radioligands used to measure brain norepinephrine transporters (NET) with positron emission tomography (PET). The objective of this study was to evaluate the suitability of [11C]MRB for drug occupancy studies of NET using atomoxetine (ATX), a NET uptake inhibitor used in the treatment of depression and attention-deficit hyperactivity disorder (ADHD). A second goal of the study was identification of a suitable reference region. Ten PET studies were performed in three anesthetized rhesus monkeys following an infusion of ATX or placebo. [11C]MRB arterial input functions and ATX plasma levels were also measured. A dose-dependent reduction of [11C]MRB volume of distribution was observed after correction for [11C]MRB plasma free fraction. ATX IC50 was estimated to be 31±10 ng/mL plasma. This corresponds to an effective dose (ED50) of 0.13 mg/kg, which is much lower than the therapeutic dose of ATX in ADHD (1.0–1.5 mg/kg). [11C]MRB binding potential BPND in the thalamus was estimated to be 1.8±0.3. Defining a reference region for a NET radiotracer is challenging due to the widespread and relatively uniform distribution of NET in the brain. Three regions were evaluated for use as reference region: caudate, putamen and occipital cortex. Caudate was found to be the most suitable for preclinical drug occupancy studies in rhesus monkeys. The IC50 estimate obtained using MRTM2 BPND without arterial blood sampling was 21±3 ng/mL (using caudate as the reference region). This study demonstrated that [11C]MRB is suitable for drug occupancy studies of NET. PMID:20869448

  9. Predictive efficacy of (11)C-PD153035 PET imaging for EGFR-tyrosine kinase inhibitor sensitivity in non-small cell lung cancer patients.

    PubMed

    Dai, Dong; Li, Xiao-Feng; Wang, Jian; Liu, Jian-Jing; Zhu, Yan-Jia; Zhang, Ying; Wang, Qi; Xu, Wen-Gui

    2016-02-15

    To determine the correlation of (11)C-PD153035 uptake with epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) sensitivity and phosphorylated EGFR (pEGFR) expression in non-small cell lung cancer (NSCLC) cell lines with different EGFR-TKI sensitivities and in their corresponding xenografts. Four human NSCLC cell lines (HCC827, PC9, A549, and H1975) in the logarithmic phase were co-incubated with (11)C-PD153035 to analyze the correlation of (11)C-PD153035 uptake with EGFR-TKI sensitivity, and EGFR/pEGFR expression. Nude mice xenograft models bearing the four NSCLCs were prepared. (11)C-PD153035 positron-emission tomography (PET)-computed tomography (CT) was used to image the xenografts and observe radioactive uptakes. Correlation of the in vivo uptakes with EGFR-TKI sensitivity, and EGFR/pEGFR expression was analyzed. HCC827 and PC9 cells, which were highly sensitive to EGFR-TKIs, exhibited higher (11)C-PD153035 uptakes than the other cells. A549 cells, which were moderately sensitive to EGFR-TKIs, showed higher uptake than the EGFR-TKI-resistant H1975 cells, which showed little or no uptake. Radioactive uptakes were positively correlated with pEGFR expression in all cells. PET-CT showed that radioactivity was highest in HCC827 xenografts. The radioactivity in PC9 xenografts was higher than that in A549 and H1975 xenografts. Tumor vs. non-tumor tissue ratio values were positively correlated with pEGFR expression in HCC827 and PC9 xenografts, but not in A549 and H1975 xenografts. In conclusion, (11)C-PD153035 can serve as an EGFR imaging agent in vitro and in vivo, and predicts sensitivity to EGFR-TKIs. This will provide an experimental basis for clinical applications of (11)C-PD153035 and individualized NSCLC therapy. PMID:26334931

  10. SWIMRT: a graphical user interface using sliding window algorithm to construct a fluence map machine file.

    PubMed

    Chow, James C L; Grigorov, Grigor N; Yazdani, Nuri

    2006-01-01

    A custom-made computer program, SWIMRT, to construct "multileaf collimator (MLC) machine" file for intensity-modulated radiotherapy (IMRT) fluence maps was developed using MATLAB and the sliding window algorithm. The user can either import a fluence map with a graphical file format created by an external treatment-planning system such as Pinnacle3 or create his or her own fluence map using the matrix editor in the program. Through comprehensive calibrations of the dose and the dimension of the imported fluence field, the user can use associated image-processing tools such as field resizing and edge trimming to modify the imported map. When the processed fluence map is suitable, a "MLC machine" file is generated for our Varian 21 EX linear accelerator with a 120-leaf Millennium MLC. This machine file is transferred to the MLC console of the LINAC to control the continuous motions of the leaves during beam irradiation. An IMRT field is then irradiated with the 2D intensity profiles, and the irradiated profiles are compared to the imported or modified fluence map. This program was verified and tested using film dosimetry to address the following uncertainties: (1) the mechanical limitation due to the leaf width and maximum traveling speed, and (2) the dosimetric limitation due to the leaf leakage/transmission and penumbra effect. Because the fluence map can be edited, resized, and processed according to the requirement of a study, SWIMRT is essential in studying and investigating the IMRT technique using the sliding window algorithm. Using this program, future work on the algorithm may include redistributing the time space between segmental fields to enhance the fluence resolution, and readjusting the timing of each leaf during delivery to avoid small fields. Possible clinical utilities and examples for SWIMRT are given in this paper. PMID:17533330

  11. Light fluence correction for quantitative determination of tissue absorption coefficient using multi-spectral optoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Brochu, Frederic M.; Joseph, James; Tomaszewski, Michal; Bohndiek, Sarah E.

    2015-07-01

    MultiSpectral Optoacoustic Tomography (MSOT) is a fast developing imaging modality, combining the high resolution and penetration depth of ultrasound with the excellent contrast from optical imaging of tissue. Absorption and scattering of the near infrared excitation light modulates the spectral profile of light as it propagates deep into biological tissue, meaning the images obtained provide only qualitative insight into the distribution of tissue chromophores. The goal of this work is to accurately recover the spectral profile of excitation light by modelling light fluence in the data reconstruction, to enable quantitative imaging. We worked with a commercial small animal MSOT scanner and developed our light fluence correction for its' cylindrical geometry. Optoacoustic image reconstruction pinpoints the sources of acoustic waves detected by the transducers and returns the initial pressure amplitude at these points. This pressure is the product of the dimensionless Grüneisen parameter, the absorption coefficient and the light fluence. Under the condition of constant Grüneisen parameter and well modelled light fluence, there is a linear relationship between the initial pressure amplitude measured in the optoacoustic image and the absorption coefficient. We were able to reproduce this linear relationship in different physical regions of an agarose gel phantom containing targets of known optical absorption coefficient, demonstrating that our light fluence model was working. We also demonstrate promising results of light fluence correction effects on in vivo data.

  12. Influence of fluence rate on radiation-induced mechanical property changes in reactor pressure vessel steels

    SciTech Connect

    Hawthorne, J.R.; Hiser, A.L. )

    1990-03-01

    This report describes a set of experiments undertaken using a 2 MW test reactor, the UBR, to qualify the significance of fluence rate to the extent of embrittlement produced in reactor pressure vessel steels at their service temperature. The test materials included two reference plates (A 302-B, A 533-B steel) and two submerged arc weld deposits (Linde 80, Linde 0091 welding fluxes). Charpy-V (C{sub v}), tension and 0.5T-CT compact specimens were employed for notch ductility, strength and fracture toughness (J-R curve) determinations, respectively. Target fluence rates were 8 {times} 10{sup 10}, 6 {times} 10{sup 11} and 9 {times} 10{sup 12} n/cm{sup 2} {minus}s{sup {minus}1}. Specimen fluences ranged from 0.5 to 3.8 {times} 10{sup 19} n/cm{sup 2}, E > 1 MeV. The data describe a fluence-rate effect which may extend to power reactor surveillance as well as test reactor facilities now in use. The dependence of embrittlement sensitivity on fluence rate appears to differ for plate and weld deposit materials. Relatively good agreement in fluence-rate effects definition was observed among the three test methods. 52 figs., 4 tabs.

  13. Determination of mixed proton/neutron fluences in the LANSCE irradiation environment

    SciTech Connect

    James, M.R.; Maloy, S.A; Sommer, W.F.; Ferguson, P.; Fowler, M.M.; Corzine, K.

    1998-12-31

    In support of the Accelerator Production of Tritium (APT) program, several materials were exposed to a high-energy proton and spallation neutron environments. Large differences in mechanical property changes in this environment are expected compared to the typical fusion or fission systems. To make proper dose correlations, it is important to accurately quantify the fluences. Activation foils consisting of a stack of disks of Co, Ni, Fe, Al, Nb and Cu were irradiated concurrent with mechanical testing samples in the Los Alamos Spallation Radiation Effects Facility (LASREF) at the Los Alamos Neutron Science Center (LANSCE) facility. The irradiation consisted of an 800 MeV, 1 mA proton beam and a W target in the beam provided a source of spallation neutrons. The maximum proton fluence was around 3 {times} 10{sup 21} p/cm{sup 2} and the maximum neutron fluence approximately 3 {times} 10{sup 20} n/cm{sup 2}. After irradiation, the foils were withdrawn and the radioactive isotopes analyzed using gamma spectroscopy. From initial estimates for the fluences and spectra derived from the Los Alamos High-Energy Transport (LAHET) Code System (LCS), comparisons to the measured levels of activation products were made. The Na-22 activation products in the Al foils were measured from different regions of the target in order to profile the spatial levels of the fluences. These tests gave empirical confirmation of the proton and neutron fluences of the irradiated samples throughout the target region.

  14. Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications.

    PubMed

    Rosenberg, M J; Séguin, F H; Waugh, C J; Rinderknecht, H G; Orozco, D; Frenje, J A; Johnson, M Gatu; Sio, H; Zylstra, A B; Sinenian, N; Li, C K; Petrasso, R D; Glebov, V Yu; Stoeckl, C; Hohenberger, M; Sangster, T C; LePape, S; Mackinnon, A J; Bionta, R M; Landen, O L; Zacharias, R A; Kim, Y; Herrmann, H W; Kilkenny, J D

    2014-04-01

    CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ∼0.5-8 MeV protons. When the fluence of incident particles becomes too high, overlap of particle tracks leads to under-counting at typical processing conditions (5 h etch in 6N NaOH at 80 °C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7-4.3-MeV protons and established that for 2.4-MeV protons, relevant for detection of DD protons, the maximum fluence that can be detected using normal processing techniques is ≲3 × 10(6) cm(-2). A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ∼50, increasing the operating yield upper limit by a comparable amount. PMID:24784597

  15. Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications

    SciTech Connect

    Rosenberg, M. J.; Séguin, F. H.; Waugh, C. J.; Rinderknecht, H. G.; Orozco, D.; Frenje, J. A.; Johnson, M. Gatu; Sio, H.; Zylstra, A. B.; Sinenian, N.; Li, C. K.; Petrasso, R. D.; Glebov, V. Yu.; Stoeckl, C.; Hohenberger, M.; Sangster, T. C.; LePape, S.; Mackinnon, A. J.; Bionta, R. M.; Landen, O. L.; Zacharias, R. A.; Kim, Y.; Herrmann, H. W.; Kilkenny, J. D.

    2014-04-14

    CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ~0.5–8 MeV protons. When the fluence of incident particles becomes too high, the overlap of particle tracks leads to under-counting at typical processing conditions (5h etch in 6N NaOH at 80°C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7–4.3-MeV protons and established that for 2.4-MeV protons, relevant for detection of DD protons, the maximum fluence that can be detected using normal processing techniques is ≲3 ×106 cm-2. A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ~50, increasing the operating yield upper limit by a comparable amount.

  16. Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications

    DOE PAGESBeta

    Rosenberg, M. J.; Séguin, F. H.; Waugh, C. J.; Rinderknecht, H. G.; Orozco, D.; Frenje, J. A.; Johnson, M. Gatu; Sio, H.; Zylstra, A. B.; Sinenian, N.; et al

    2014-04-14

    CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ~0.5–8 MeV protons. When the fluence of incident particles becomes too high, the overlap of particle tracks leads to under-counting at typical processing conditions (5h etch in 6N NaOH at 80°C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7–4.3-MeV protons and established that for 2.4-MeV protons, relevant for detectionmore » of DD protons, the maximum fluence that can be detected using normal processing techniques is ≲3 ×106 cm-2. A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ~50, increasing the operating yield upper limit by a comparable amount.« less

  17. Ablating the aryl hydrocarbon receptor (AhR) in CD11c+ cells perturbs intestinal epithelium development and intestinal immunity

    PubMed Central

    Chng, Song Hui; Kundu, Parag; Dominguez-Brauer, Carmen; Teo, Wei Ling; Kawajiri, Kaname; Fujii-Kuriyama, Yoshiaki; Mak, Tak Wah; Pettersson, Sven

    2016-01-01

    Diet and microbiome derived indole derivatives are known to activate the ligand induced transcription factor, the Aryl hydrocarbon Receptor (AhR). While the current understanding of AhR biology has confirmed its role in mucosal lymphocytes, its function in intestinal antigen presenting cells (APCs) is poorly understood. Here, we report that Cre-mediated deletion of AhR in CD11c-expressing cells in C57/BL6 mice is associated with altered intestinal epithelial morphogenesis in vivo. Moreover, when co-cultured with AhR-deficient DCs ex vivo, intestinal organoids showed reduced SRY (sex determining region Y)-box 9 and increased Mucin 2 expression, which correlates with reduced Paneth cells and increased goblet cell differentiation, similar to the data obtained in vivo. Further, characterization of intestinal APC subsets, devoid of AhR, revealed an expression pattern associated with aberrant intrinsic Wnt pathway regulation. At a functional level, the loss of AhR in APCs resulted in a dysfunctional epithelial barrier, associated with a more aggressive chemically induced colitis compared to wild type animals. Our results are consistent with a model whereby the AhR signalling pathway may participate in the regulation of innate immunity through intestinal epithelium development and mucosal immunity. PMID:27068235

  18. Limitations of SRTM, Logan graphical method, and equilibrium analysis for measuring transient dopamine release with [(11)C]raclopride PET.

    PubMed

    Sullivan, Jenna M; Kim, Su Jin; Cosgrove, Kelly P; Morris, Evan D

    2013-01-01

    Conventional PET methods to estimate [(11)C]raclopride binding potential (BP ND) assume that endogenous dopamine concentration does not change during the scan time. However, this assumption is purposely violated in studies using pharmacological or behavioral stimuli to invoke acute dopamine release. When the assumption of steady-state dopamine is violated, conventional analysis methods may produce biased or even unusable estimates of BP ND. To illustrate this problem, we examined the effect of scan duration on ΔBP ND estimated by three common analysis methods (simplified reference tissue model, Logan graphical reference method, and equilibrium analysis) applied to simulated and experimental single-scan activation studies. The activation - dopamine release - in both the simulated and experimental studies was brief. Simulations showed ΔBP ND to be highly dependent on the window of data used to determine BP ND in the activation state. A similar pattern was seen in the data from human smoking studies. No such pattern of ΔBP ND dependence on the window of data used was apparent in simulations where dopamine was held constant. The dependence of ΔBP ND on the duration of data analyzed illustrates the inability of conventional methods to reliably quantify short-lived increases in endogenous dopamine. PMID:23638336

  19. First direct measurement of the 11C (α ,p )14N stellar reaction by an extended thick-target method

    NASA Astrophysics Data System (ADS)

    Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, D. N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.

    2016-06-01

    The 11C(α,p ) 14N reaction is an important α -induced reaction competing with β -limited hydrogen-burning processes in high-temperature explosive stars. We directly measured its reaction cross sections both for the ground-state transition (α ,p0) and the excited-state transitions (α ,p1) and (α ,p2) at relevant stellar energies 1.3-4.5 MeV by an extended thick-target method featuring time of flight for the first time. We revised the reaction rate by numerical integration including the (α ,p1) and (α ,p2) contributions and also low-lying resonances of (α ,p0) using both the present and the previous experimental data which were totally neglected in the previous compilation works. The present total reaction rate lies between the previous (α ,p0) rate and the total rate of the Hauser-Feshbach statistical model calculation, which is consistent with the relevant explosive hydrogen-burning scenarios such as the ν p process.

  20. D2 dopamine receptors in neuroleptic-naive schizophrenic patients. A positron emission tomography study with (11C)raclopride

    SciTech Connect

    Farde, L.; Wiesel, F.A.; Stone-Elander, S.; Halldin, C.; Nordstroem, A.L.H.; Hall, H.; Sedvall, G. )

    1990-03-01

    Several groups have reported increased densities of D2 dopamine receptors in the basal ganglia of schizophrenic brains postmortem. The significance of this finding has been questioned, since an upregulation of receptor number may be a neuronal response to neuroleptic drug treatment. We have used positron emission tomography and ({sup 11}C)raclopride to examine central D2 dopamine receptor binding in 20 healthy subjects and 18 newly admitted, young, neuroleptic-naive patients with schizophrenia. An in vivo saturation procedure was applied for quantitative determination of D2 dopamine receptor density (Bmax) and affinity (Kd). When the two groups were compared, no significant difference in Bmax or Kd values was found in the putamen or the caudate nucleus. The hypothesis of generally elevated central D2 dopamine receptor densities in schizophrenia was thus not supported by the present findings. In the patients but not in the healthy controls, significantly higher densities were found in the left than in the right putamen but not in the caudate nucleus.

  1. N-(/sup 11/C)-methyl-p-substituted phentermine analogs as potential brain blood flow agents for positron tomography

    SciTech Connect

    Kizuka, H.; Elmaleh, D.R.; Boudreaux, G.J.; Anderton, K.D.; Strauss, H.W.; Ackerman, R.H.; Brownell, G.L.

    1984-01-01

    The addition of a methyl group to the ..cap alpha..-position of amphetamine increases both the lipophilicity of the agent and its resistance to metabolism by monoamine oxidase. In addition, since tritium substituted phenteramine analog studies suggested that the p-halo phentermines had a greater concentration in the brain and prolonged retention time, the authors evaluated the biological behavior of positron labeled ..cap alpha..-methylamphetamine (phenteramine) in rats, dogs and monkeys. The N-(/sup 11/C) methyl analogs of p-chloro (I) and p-fluoro (II) phentermines were prepared by methylation of their primary amines using /sup 11/Ch/sub 3/I. Biodistribution studies in rats shows brain uptake is in the range of 1% dose/gr at 5 and 15 min for both agents. The activity in blood and eyes is low. Sequential images of the dogs' brain over 1 hour revealed a clearance of <15%. Images of the monkey brain were also obtained using a MGH positron camera PCR-I.

  2. Dynamics of CD11c+ dendritic cell subsets in lymph nodes draining the site of intestinal nematode infection

    PubMed Central

    Balic, Adam; Smith, Katherine A.; Harcus, Yvonne; Maizels, Rick M.

    2009-01-01

    Helminth parasites drive dominant Th2 responses through an as yet unidentified pathway. We have previously shown that the rodent gastrointestinal nematode Nippostrongylus brasiliensis secretes products which selectively activate in vitro-derived dendritic cells to induce Th2 responses on in vivo transfer. We now show that, during active infection with this parasite, the draining mesenteric lymph node dendritic cell population is altered significantly. Although there is substantial expansion of DC numbers during infection, the CD86hi-CD8αint-CD11b− subset is markedly diminished, and expression levels of CD40, CD86 and CD103 are reduced. Notably, the reduced frequency of CD8αint DCs is evident only in those mesenteric lymph nodes draining the anterior site of infestation. In infections with the longer lived Heligmosomoides polygyrus, the proportion of CD8αint DCs in the MLNC falls to below 10% of total DC numbers by 35 days post-infection. Further, infection alters TLR responsiveness, as IL-12 production (as measured by ex vivo intracellular staining of CD11c+ DCs) in response to LPS stimulation is reduced, while IL-6, TNF-α and in particular, IL-10 all increase following infection with either nematode parasite. These changes suggest the possibility that helminth parasites modulate gastrointestinal immunity both by inhibiting migration of CD8αint DCs to the draining lymph nodes, and modifying DC responsiveness in a manner which favours a Th2 outcome. PMID:19766674

  3. Ablating the aryl hydrocarbon receptor (AhR) in CD11c+ cells perturbs intestinal epithelium development and intestinal immunity.

    PubMed

    Chng, Song Hui; Kundu, Parag; Dominguez-Brauer, Carmen; Teo, Wei Ling; Kawajiri, Kaname; Fujii-Kuriyama, Yoshiaki; Mak, Tak Wah; Pettersson, Sven

    2016-01-01

    Diet and microbiome derived indole derivatives are known to activate the ligand induced transcription factor, the Aryl hydrocarbon Receptor (AhR). While the current understanding of AhR biology has confirmed its role in mucosal lymphocytes, its function in intestinal antigen presenting cells (APCs) is poorly understood. Here, we report that Cre-mediated deletion of AhR in CD11c-expressing cells in C57/BL6 mice is associated with altered intestinal epithelial morphogenesis in vivo. Moreover, when co-cultured with AhR-deficient DCs ex vivo, intestinal organoids showed reduced SRY (sex determining region Y)-box 9 and increased Mucin 2 expression, which correlates with reduced Paneth cells and increased goblet cell differentiation, similar to the data obtained in vivo. Further, characterization of intestinal APC subsets, devoid of AhR, revealed an expression pattern associated with aberrant intrinsic Wnt pathway regulation. At a functional level, the loss of AhR in APCs resulted in a dysfunctional epithelial barrier, associated with a more aggressive chemically induced colitis compared to wild type animals. Our results are consistent with a model whereby the AhR signalling pathway may participate in the regulation of innate immunity through intestinal epithelium development and mucosal immunity. PMID:27068235

  4. 11C-Methionine-PET: A novel and sensitive tool for monitoring of early response to treatment in multiple myeloma

    PubMed Central

    Albert, Christa; Herrmann, Ken; Jörg, Gerhard; Samnick, Samuel; Einsele, Herrmann; Knop, Stefan; Buck, Andreas K.

    2015-01-01

    Multiple myeloma (MM) remains an essentially incurable hematologic malignancy. However, new treatment modalities and novel drugs have been introduced and thus additional tools for therapy monitoring are increasingly needed. Therefore, we evaluated the radiotracers 11C-Methionine (paraprotein-biosynthesis) and 18F-FDG (glucose-utilization) for monitoring response to anti-myeloma-therapy and outcome prediction. Influence of proteasome-inhibition on radiotracer-uptake of different MM cell-lines and patient-derived CD138+ plasma cells was analyzed and related to tumor-biology. Mice xenotransplanted with MM.1S tumors underwent MET- and FDG-μPET. Tumor-to-background ratios before and after 24 h, 8 and 15 days treatment with bortezomib were correlated to survival. Treatment reduced both MET and FDG uptake; changes in tracer-retention correlated with a switch from high to low CD138-expression. In xenotransplanted mice, MET-uptake significantly decreased by 30–79% as early as 24 h after bortezomib injection. No significant differences were detected thus early with FDG. This finding was confirmed in patient-derived MM cells. Importantly, early reduction of MET- but not FDG-uptake correlated with improved survival and reduced tumor burden in mice. Our results suggest that MET is superior to FDG in very early assessment of response to anti-myeloma-therapy. Early changes in MET-uptake have predictive potential regarding response and survival. MET-PET holds promise to individualize therapies in MM in future. PMID:25762625

  5. CD11c(+) monocyte/macrophages promote chronic Helicobacter hepaticus-induced intestinal inflammation through the production of IL-23.

    PubMed

    Arnold, I C; Mathisen, S; Schulthess, J; Danne, C; Hegazy, A N; Powrie, F

    2016-03-01

    In inflammatory bowel diseases, a breakdown in host microbial interactions accompanies sustained activation of immune cells in the gut. Functional studies suggest a key role for interleukin-23 (IL-23) in orchestrating intestinal inflammation. IL-23 can be produced by various mononuclear phagocytes (MNPs) following acute microbial stimulation, but little is known about the key cellular sources of IL-23 that drive chronic intestinal inflammation. Here we have addressed this question using a physiological model of bacteria-driven colitis. By combining conditional gene ablation and gene expression profiling, we found that IL-23 production by CD11c(+) MNPs was essential to trigger intestinal immunopathology and identified MHCII(+) monocytes and macrophages as the major source of IL-23. Expression of IL-23 by monocytes was acquired during their differentiation in the intestine and correlated with the expression of major histocompatibility complex class II (MHCII) and CD64. In contrast, Batf3-dependent CD103(+) CD11b(-) dendritic cells were dispensable for bacteria-induced colitis in this model. These studies reinforce the pathogenic role of monocytes in dysregulated responses to intestinal bacteria and identify production of IL-23 as a key component of this response. Further understanding of the functional sources of IL-23 in diverse forms of intestinal inflammation may lead to novel therapeutic strategies aimed at interrupting IL-23-driven immune pathology. PMID:26242598

  6. A comparison study of 11C-methionine and 18F-fluorodeoxyglucose positron emission tomography-computed tomography scans in evaluation of patients with recurrent brain tumors

    PubMed Central

    Sharma, Rajnish; D’Souza, Maria; Jaimini, Abhinav; Hazari, Puja Panwar; Saw, Sanjeev; Pandey, Santosh; Singh, Dinesh; Solanki, Yachna; Kumar, Nitin; Mishra, Anil K.; Mondal, Anupam

    2016-01-01

    Introduction: 11C-methonine ([11C]-MET) positron emission tomography-computed tomography (PET-CT) is a well-established technique for evaluation of tumor for diagnosis and treatment planning in neurooncology. [11C]-MET reflects amino acid transport and has been shown to be more sensitive than magnetic resonance imaging (MRI) in stereotactic biopsy planning. This study compared fluorodeoxyglucose (FDG) PET-CT and MET PET-CT in the detection of various brain tumors. Materials and Methods: Sixty-four subjects of brain tumor treated by surgery, chemotherapy, and/or radiotherapy were subjected to [18F]-FDG, [11C]-MET, and MRI scan. The lesion was analyzed semiquantitatively using tumor to normal contralateral ratio. The diagnosis was confirmed by surgery, stereotactic biopsy, clinical follow-up, MRI, or CT scans. Results: Tumor recurrence was found in 5 out of 22 patients on [F-18] FDG scan while [11C]-MET was able to detect recurrence in 18 out of 22 patients in low-grade gliomas. Two of these patients were false positive for the presence of recurrence of tumor and later found to be harboring necrosis. Among oligodendroglioma, medulloblastoma and high-grade glioma out of 42 patients 39 were found to be concordant MET and FDG scans. On semiquantitative analysis, mean T/NT ratio was found to be 2.96 ± 0.94 for lesions positive for recurrence of tumors and 1.18 ± 0.74 for lesions negative for recurrence of tumor on [11C]-MET scan. While the ratio for FDG scan on semiquantitative analysis was found to be 2.05 ± 1.04 for lesions positive for recurrence of tumors and 0.52 ± 0.15 for lesions negative for recurrence of tumors. Conclusion: The study highlight that [11C]-MET is superior to [18F]-FDG PET scans to detect recurrence in low-grade glioma. A cut-off value of target to nontarget value of 1.47 is a useful parameter to distinguish benign from malignant lesion on an [11C]-MET Scan. Both [18F]-FDG and [11C]-MET scans were found to be useful in high-grade astrocytoma

  7. Brain and Whole-Body Imaging in Rhesus Monkeys of 11C-NOP-1A, a Promising PET Radioligand for Nociceptin/Orphanin FQ Peptide Receptors

    PubMed Central

    Kimura, Yasuyuki; Fujita, Masahiro; Hong, Jinsoo; Lohith, Talakad G.; Gladding, Robert L.; Zoghbi, Sami S.; Tauscher, Johannes A.; Goebl, Nancy; Rash, Karen S.; Chen, Zhaogen; Pedregal, Concepcion; Barth, Vanessa N.; Pike, Victor W.; Innis, Robert B.

    2011-01-01

    Our laboratory developed (S)-3-(2′-fluoro-6′,7′-dihydrospiro [piperidine-4,4′-thieno[3,2-c]pyran]-1-yl)-2-(2-fluorobenzyl)-N-methylpropanamide (11C-NOP-1A), a new radioligand for the nociceptin/orphanin FQ peptide (NOP) receptor, with high affinity (Ki, 0.15 nM) and appropriate lipophilicity (measured logD, 3.4) for PET brain imaging. Here, we assessed the utility of 11C-NOP-1A for quantifying NOP receptors in the monkey brain and estimated the radiation safety profile of this radioligand based on its biodistribution in monkeys. Methods Baseline and blocking PET scans were acquired from head to thigh for 3 rhesus monkeys for approximately 120 min after 11C-NOP-1A injection. These 6 PET scans were used to quantify NOP receptors in the brain and to estimate radiation exposure to organs of the body. In the blocked scans, a selective nonradioactive NOP receptor antagonist (SB-612111; 1 mg/kg intravenously) was administered before 11C-NOP-1A. In all scans, arterial blood was sampled to measure the parent radioligand 11C-NOP-1A. Distribution volume (VT; a measure of receptor density) was calculated with a compartment model using brain and arterial plasma data. Radiation-absorbed doses were calculated using the MIRD Committee scheme. Results After 11C-NOP-1A injection, peak uptake of radioactivity in the brain had a high concentration (~5 standardized uptake value), occurred early (~12 min), and thereafter washed out quickly. VT (mL cm−3) was highest in the neocortex (~20) and lowest in hypothalamus and cerebellum (~13). SB-612111 blocked approximately 50%–70% of uptake and reduced VT in all brain regions to approximately 7 mL cm−3. Distribution was well identified within 60 min of injection and stable for the remaining 60 min, consistent with only parent radioligand and not radiometabolites entering the brain. Whole-body scans confirmed that the brain had specific (i.e., displaceable) binding but could not detect specific binding in peripheral organs. The

  8. 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

  9. Quantification of [(11)C]PIB PET for imaging myelin in the human brain: a test-retest reproducibility study in high-resolution research tomography.

    PubMed

    Veronese, Mattia; Bodini, Benedetta; García-Lorenzo, Daniel; Battaglini, Marco; Bongarzone, Salvatore; Comtat, Claude; Bottlaender, Michel; Stankoff, Bruno; Turkheimer, Federico E

    2015-11-01

    An accurate in vivo measure of myelin content is essential to deepen our insight into the mechanisms underlying demyelinating and dysmyelinating neurological disorders, and to evaluate the effects of emerging remyelinating treatments. Recently [(11)C]PIB, a positron emission tomography (PET) tracer originally conceived as a beta-amyloid marker, has been shown to be sensitive to myelin changes in preclinical models and humans. In this work, we propose a reference-region methodology for the voxelwise quantification of brain white-matter (WM) binding for [(11)C]PIB. This methodology consists of a supervised procedure for the automatic extraction of a reference region and the application of the Logan graphical method to generate distribution volume ratio (DVR) maps. This approach was assessed on a test-retest group of 10 healthy volunteers using a high-resolution PET tomograph. The [(11)C]PIB PET tracer binding was shown to be up to 23% higher in WM compared with gray matter, depending on the image reconstruction. The DVR estimates were characterized by high reliability (outliers <1%) and reproducibility (intraclass correlation coefficient (ICC) >0.95). [(11)C]PIB parametric maps were also found to be significantly correlated (R(2)>0.50) to mRNA expressions of the most represented proteins in the myelin sheath. On the contrary, no correlation was found between [(11)C]PIB imaging and nonmyelin-associated proteins. PMID:26058700

  10. Manipulation of [11C]-5-hydroxytryptophan and 6-[18F]fluoro-3,4-dihydroxy-L-phenylalanine accumulation in neuroendocrine tumor cells.

    PubMed

    Neels, Oliver C; Koopmans, Klaas P; Jager, Pieter L; Vercauteren, Laya; van Waarde, Aren; Doorduin, Janine; Timmer-Bosscha, Hetty; Brouwers, Adrienne H; de Vries, Elisabeth G E; Dierckx, Rudi A J O; Kema, Ido P; Elsinga, Philip H

    2008-09-01

    [(11)C]-5-Hydroxytryptophan ([(11)C]HTP) and 6-[(18)F]fluoro-3,4-dihydroxy-l-phenylalanine ([(18)F]FDOPA) are used to image neuroendocrine tumors with positron emission tomography. The precise mechanism by which these tracers accumulate in tumor cells is unknown. We aimed to study tracer uptake via large amino acid transporters, peripheral decarboxylation (inhibited by carbidopa), and intracellular breakdown by monoamine oxidase (MAO). [(11)C]HTP and [(18)F]FDOPA tracer accumulation was assessed in a human neuroendocrine tumor cell line, BON. The carbidopa experiments were done in a tumor-bearing mouse model. Intracellular [(11)C]HTP accumulation was 2-fold higher than that of [(18)F]FDOPA. Cellular transport of both tracers was inhibited by amino-2-norbornanecarboxylic acid. The MAO inhibitors clorgyline and pargyline increased tracer accumulation in vitro. Carbidopa did not influence tracer accumulation in vitro but improved tumor imaging in vivo. Despite lower accumulation in vitro, visualization of [(18)F]FDOPA is superior to [(11)C]HTP in the neuroendocrine pancreatic tumor xenograft model. This could be a consequence of the serotonin saturation of BON cells in the in vivo model. PMID:18757434

  11. Characterisation of [11C]PR04.MZ in Papio anubis baboon: A selective high-affinity radioligand for quantitative imaging of the dopamine transporter

    SciTech Connect

    Riss P. J.; Fowler J.; Riss, P.J.; Hooker, J.M.; Shea, C.; Xu, Y.; Carter, P.; Warner, D.; Ferrari V.; Kim, S.W.; Aigbirhio, F.I.; Fowler, J.S.; Roesch, F.

    2011-10-25

    N-(4-fluorobut-2-yn-1-yl)-2{beta}-carbomethoxy-3{beta}-(4{prime}-tolyl)nortropane (PR04.MZ, 1) is a PET radioligand for the non-invasive exploration of the function of the cerebral dopamine transporter (DAT). A reliable automated process for routine production of the carbon-11 labelled analogue [{sup 11}C]PR04.MZ ([{sup 11}C]-1) has been developed using GMP compliant equipment. An adult female Papioanubis baboon was studied using a test-retest protocol with [{sup 11}C]-1 in order to assess test-retest reliability, metabolism and CNS distribution profile of the tracer in non-human primates. Blood sampling was performed throughout the studies for determination of the free fraction in plasma (fP), plasma input functions and metabolic degradation of the radiotracer [{sup 11}C]-1. Time-activity curves were derived for the putamen, the caudate nucleus, the ventral striatum, the midbrain and the cerebellum. Distribution volumes (VT) and non-displaceable binding potentials (BPND) for various brain regions and the blood were obtained from kinetic modelling. [{sup 11}C]-1 shows promising results as aselective marker of the presynaptic dopamine transporter. With the reliable visualisation of the extra-striatal dopaminergic neurons and no indication on labelled metabolites, the tracer provides excellent potential for translation into man.

  12. Radiosynthesis of [11C]SNAP-7941—the first PET-tracer for the melanin concentrating hormone receptor 1 (MCHR1)

    PubMed Central

    Philippe, C.; Schirmer, E.; Mitterhauser, M.; Shanab, K.; Lanzenberger, R.; Karanikas, G.; Spreitzer, H.; Viernstein, H.; Wadsak, W.

    2012-01-01

    The melanin concentrating hormone (MCH) system is a new target to treat human disorders. Our aim was the preparation of the first PET-tracer for the MCHR1. [11C]SNAP-7941 is a carbon-11 labeled analog of the published MCHR1 antagonist SNAP-7941. The optimum reaction conditions were 2 min reaction time, ≤25 °C reaction temperature, and 2 mg/mL precursor (SNAP-acid) in acetonitrile, using [11C]CH3OTf as methylation agent. [11C]SNAP-7941 was prepared in a reliable and feasible manner with high radiochemical yields (2.9±1.6 GBq; 11.5±6.4% EOB, n=15). PMID:22858577

  13. Parameter evaluation and fully-automated radiosynthesis of [(11)C]harmine for imaging of MAO-A for clinical trials.

    PubMed

    Philippe, C; Zeilinger, M; Mitterhauser, M; Dumanic, M; Lanzenberger, R; Hacker, M; Wadsak, W

    2015-03-01

    The aim of the present study was the evaluation and automation of the radiosynthesis of [(11)C]harmine for clinical trials. The following parameters have been investigated: amount of base, precursor concentration, solvent, reaction temperature and time. The optimum reaction conditions were determined to be 2-3mg/mL precursor activated with 1eq. 5M NaOH in DMSO, 80°C reaction temperature and 2min reaction time. Under these conditions 6.1±1GBq (51.0±11% based on [(11)C]CH3I, corrected for decay) of [(11)C]harmine (n=72) were obtained. The specific activity was 101.32±28.2GBq/µmol (at EOS). All quality control parameters were in accordance with the standards for parenteral human application. Due to its reliability and high yields, this fully-automated synthesis method can be used as routine set-up. PMID:25594603

  14. Characteristics of the chemical forms of 11C, 13N, and 15O induced in air by the operation of a 100 MeV electron linear accelerator.

    PubMed

    Endo, A; Kikuchi, M; Izawa, S; Ikezawa, Y

    1995-01-01

    To characterize airborne radioactivity induced by the operation of high-energy accelerators, the fractions of aerosol and gaseous components, and the chemical forms of 11C, 13N, and 15O produced in the air of a target room of a 100 MeV electron linear accelerator were studied. Measurements of radioactivity using a particulate air sampling filter and a gas flow-through ionization chamber showed that more than 98% of 11C, 13N, and 15O were present as gaseous forms. Their chemical forms, detected by means of radio-gas chromatography, were 11C as CO2; 13N as N2 and NO; and 15O as O2 and NO. Machine operating conditions, which affect the compositions of the induced radionuclides and of their chemical forms, and the resulting effect on the estimation of internal doses are discussed. PMID:7989199

  15. The Gene Expression Profile of CD11c+CD8α− Dendritic Cells in the Pre-Diabetic Pancreas of the NOD Mouse

    PubMed Central

    Beumer, Wouter; Welzen-Coppens, Jojanneke M. C.; van Helden-Meeuwsen, Cornelia G.; Gibney, Sinead M.; Drexhage, Hemmo A.; Versnel, Marjan A.

    2014-01-01

    Two major dendritic cell (DC) subsets have been described in the pancreas of mice: The CD11c+CD8α− DCs (strong CD4+ T cell proliferation inducers) and the CD8α+CD103+ DCs (T cell apoptosis inducers). Here we analyzed the larger subset of CD11c+CD8α− DCs isolated from the pancreas of pre-diabetic NOD mice for genome-wide gene expression (validated by Q-PCR) to elucidate abnormalities in underlying gene expression networks. CD11c+CD8α− DCs were isolated from 5 week old NOD and control C57BL/6 pancreas. The steady state pancreatic NOD CD11c+CD8α− DCs showed a reduced expression of several gene networks important for the prime functions of these cells, i.e. for cell renewal, immune tolerance induction, migration and for the provision of growth factors including those for beta cell regeneration. A functional in vivo BrdU incorporation test showed the reduced proliferation of steady state pancreatic DC. The reduced expression of tolerance induction genes (CD200R, CCR5 and CD24) was supported on the protein level by flow cytometry. Also previously published functional tests on maturation, immune stimulation and migration confirm the molecular deficits of NOD steady state DC. Despite these deficiencies NOD pancreas CD11c+CD8α− DCs showed a hyperreactivity to LPS, which resulted in an enhanced pro-inflammatory state characterized by a gene profile of an enhanced expression of a number of classical inflammatory cytokines. The enhanced up-regulation of inflammatory genes was supported by the in vitro cytokine production profile of the DCs. In conclusion, our data show that NOD pancreatic CD11c+CD8α− DCs show various deficiencies in steady state, while hyperreactive when encountering a danger signal such as LPS. PMID:25166904

  16. Amphetamine Decreases α2C-Adrenoceptor Binding of [11C]ORM-13070: A PET Study in the Primate Brain

    PubMed Central

    Hughes, Zoë A; Haaparanta-Solin, Merja; Stepanov, Vladimir; Nakao, Ryuji; Varnäs, Katarina; Varrone, Andrea; Arponen, Eveliina; Marjamäki, Päivi; Pohjanoksa, Katariina; Vuorilehto, Lauri; Babalola, Phebian A; Solin, Olof; Grimwood, Sarah; Sallinen, Jukka; Farde, Lars; Scheinin, Mika; Halldin, Christer

    2015-01-01

    Background: The neurotransmitter norepinephrine has been implicated in psychiatric and neurodegenerative disorders. Examination of synaptic norepinephrine concentrations in the living brain may be possible with positron emission tomography (PET), but has been hampered by the lack of suitable radioligands. Methods: We explored the use of the novel α2C-adrenoceptor antagonist PET tracer [11C]ORM-13070 for measurement of amphetamine-induced changes in synaptic norepinephrine. The effect of amphetamine on [11C]ORM-13070 binding was evaluated ex vivo in rat brain sections and in vivo with PET imaging in monkeys. Results: Microdialysis experiments confirmed amphetamine-induced elevations in rat striatal norepinephrine and dopamine concentrations. Regional [11C]ORM-13070 receptor binding was high in the striatum and low in the cerebellum. After injection of [11C]ORM-13070 in rats, mean striatal specific binding ratios, determined using cerebellum as a reference region, were 1.4±0.3 after vehicle pretreatment and 1.2±0.2 after amphetamine administration (0.3mg/kg, subcutaneous). Injection of [11C]ORM-13070 in non-human primates resulted in mean striatal binding potential (BP ND) estimates of 0.65±0.12 at baseline. Intravenous administration of amphetamine (0.5 and 1.0mg/kg, i.v.) reduced BP ND values by 31–50%. Amphetamine (0.3mg/kg, subcutaneous) increased extracellular norepinephrine (by 400%) and dopamine (by 270%) in rat striata. Conclusions: Together, these results indicate that [11C]ORM-13070 may be a useful tool for evaluation of synaptic norepinephrine concentrations in vivo. Future studies are required to further understand a potential contribution of dopamine to the amphetamine-induced effect. PMID:25522417

  17. [11C]MADAM Used as a Model for Understanding the Radiometabolism of Diphenyl Sulfide Radioligands for Positron Emission Tomography (PET)

    PubMed Central

    Gourand, Fabienne; Amini, Nahid; Jia, Zhisheng; Stone-Elander, Sharon; Guilloteau, Denis; Barré, Louisa; Halldin, Christer

    2015-01-01

    In quantitative PET measurements, the analysis of radiometabolites in plasma is essential for determining the exact arterial input function. Diphenyl sulfide compounds are promising PET and SPECT radioligands for in vivo quantification of the serotonin transporter (SERT) and it is therefore important to investigate their radiometabolism. We have chosen to explore the radiometabolic profile of [11C]MADAM, one of these radioligands widely used for in vivo PET-SERT studies. The metabolism of [11C]MADAM/MADAM was investigated using rat and human liver microsomes (RLM and HLM) in combination with radio-HPLC or UHPLC/Q-ToF-MS for their identification. The effect of carrier on the radiometabolic rate of the radioligand [11C]MADAM in vitro and in vivo was examined by radio-HPLC. RLM and HLM incubations were carried out at two different carrier concentrations of 1 and 10 μM. Urine samples after perfusion of [11C]MADAM/MADAM in rats were also analysed by radio-HPLC. Analysis by UHPLC/Q-ToF-MS identified the metabolites produced in vitro to be results of N-demethylation, S-oxidation and benzylic hydroxylation. The presence of carrier greatly affected the radiometabolism rate of [11C]MADAM in both RLM/HLM experiments and in vivo rat studies. The good concordance between the results predicted by RLM and HLM experiments and the in vivo data obtained in rat studies indicate that the kinetics of the radiometabolism of the radioligand [11C]MADAM is dose-dependent. This issue needs to be addressed when the diarylsulfide class of compounds are used in PET quantifications of SERT. PMID:26367261

  18. Fully automated preparation of [11C]choline and [18F]fluoromethylcholine using TracerLab synthesis modules and facilitated quality control using analytical HPLC.

    PubMed

    Shao, Xia; Hockley, Brian G; Hoareau, Raphaël; Schnau, Paul L; Scott, Peter J H

    2011-02-01

    Modifications of a GE TracerLab FX(C-Pro), which can be implemented for solid-phase [(11)C]methylation are described. The simplified procedure for synthesis of [(11)C]choline uses a single Sep-Pak CM-Light cation-exchange cartridge for both solid-supported reaction and purification. Compared with the commonly used two Sep-Pak method, the low back-pressure of this Sep-Pak enables efficient and reliable production of [(11)C]choline using a TracerLab FX(C-Pro) without requirement for any gas pressure adjustment. Typical radiochemical yields (RCY) are >60%, radiochemical purity (RCP) is 99.9% and levels of residual precursor in the final product, which may inhibit the uptake of [(11)C]choline, are reduced to 1 μg/mL. Similarly, modification of a GE TracerLab FX(FN) is reported which enables gas-phase production of [(18)F]fluoromethylcholine, suitable for pre-clinical use, (in 4-6% RCY and >99.7% RCP) using a related Sep-Pak method. These modifications can be utilized for solid-phase [(11)C]methylation and [(18)F]fluoromethylation of other radiotracers, and allow straightforward switching to other module configurations for solution-phase radiochemistry or loop chemistry. In addition, we report a convenient HPLC ion chromatography method, which can monitor residual precursor and the radiochemical purity of product at the same time, providing highly efficient quality control for routine clinical application. The reported HPLC method is appropriate for analysis of doses of both [(11)C]choline and [(18)F]fluoromethylcholine, and eliminates the need for a GC method to determine residual precursor levels. PMID:21115355

  19. Visualization of angiogenesis during cancer development in the polyoma middle T breast cancer model: molecular imaging with (R)-[11C]PAQ

    PubMed Central

    2014-01-01

    Background Vascular endothelial growth factor receptor 2 (VEGFR2) is a crucial mediator of tumour angiogenesis. High expression levels of the receptor have been correlated to poor prognosis in cancer patients. Reliable imaging biomarkers for stratifying patients for anti-angiogenic therapy could therefore be valuable for increasing treatment success rates. The aim of this study was to investigate the pharmacokinetics and angiogenesis imaging abilities of the VEGFR2-targeting positron emission tomography (PET) tracer (R)-[11C]PAQ. Methods (R)-[11C]PAQ was evaluated in the mouse mammary tumour virus-polyoma middle T (MMTV-PyMT) model of metastatic breast cancer. Mice at different stages of disease progression were imaged with (R)-[11C]PAQ PET, and results were compared to those obtained with [18 F]FDG PET and magnetic resonance imaging. (R)-[11C]PAQ uptake levels were also compared to ex vivo immunofluorescence analysis of tumour- and angiogenesis-specific biomarkers. Additional pharmacokinetic studies were performed in rat and mouse. Results A heterogeneous uptake of (R)-[11C]PAQ was observed in the tumorous mammary glands. Ex vivo analysis confirmed the co-localization of areas with high radioactivity uptake and areas with elevated levels of VEGFR2. In some animals, a high focal uptake was observed in the lungs. The lung uptake correlated to metastatic and angiogenic activity, but not to uptake of [18 F]FDG PET. The pharmacokinetic studies revealed a limited metabolism and excretion during the 1-h scan and a distribution of radioactivity mainly to the liver, kidneys and lungs. In rat, a high uptake was additionally observed in adrenal and parathyroid glands. Conclusion The results indicate that (R)-[11C]PAQ is a promising imaging biomarker for visualization of angiogenesis, based on VEGFR2 expression, in primary tumours and during metastasis development. PMID:24670127

  20. Multidiagnostic analysis of ion dynamics in ultrafast laser ablation of metals over a large fluence range

    SciTech Connect

    Anoop, K. K. Bruzzese, R.; Amoruso, S.; Polek, M. P.; Harilal, S. S.

    2015-02-28

    The dynamics of ions in ultrafast laser ablation of metals is studied over fluences ranging from the ablation threshold up to ≈75 J/cm{sup 2} by means of three well-established diagnostic techniques. Langmuir probe, Faraday cup, and spectrally resolved intensified charge coupled device imaging simultaneously monitored the ions produced during ultrafast laser ablation of a pure copper target with 800 nm, ≈50 fs, Ti: Sapphire laser pulses. The fluence dependence of ion yield is analyzed, resulting in the observance of three different regimes. The specific ion yield shows a maximum at about 4–5 J/cm{sup 2}, followed by a gradual reduction and a transition to a high-fluence regime above ≈50 J/cm{sup 2}. The fluence dependence of the copper ions angular distribution is also analyzed, observing a gradual increase in forward-peaking of Cu ions for fluences up to ≈10 J/cm{sup 2}. A broader ion component is observed at larger angles for fluences larger than ≈10 J/cm{sup 2}. Finally, an experimental characterization of the ionic angular distribution for several metallic targets (Mg, Al, Cr, Fe, Cu, and W) is carried out at a relatively high fluence of ≈66 J/cm{sup 2}. Interestingly, the ion emission from the volatile metals shows a narrow, forward-peaked distribution, and a high peak ion yield compared to the refractory metals. Moreover, the width of ionic angular distributions presents a striking correlation with the peak ion yield.

  1. {sup 11}C-methionine PET improves the target volume delineation of meningiomas treated with stereotactic fractionated radiotherapy

    SciTech Connect

    Grosu, Anca-Ligia . E-mail: anca-ligia.grosu@lrz.tum.de; Weber, Wolfgang A.; Astner, Sabrina T.; Adam, Markus; Krause, Bernd J.; Schwaiger, Markus; Molls, Michael; Nieder, Carsten

    2006-10-01

    Purpose: To evaluate the role of {sup 11}C-methionine positron emission tomography (MET-PET) in target volume delineation for meningiomas and to determine the interobserver variability. Methods and Materials: Two independent observers performed treatment planning in 10 patients according to a prospective written protocol. In the first step, they used coregistered computed tomography (CT) and magnetic resonance imaging (MRI). In the second step, MET-PET was added to CT/MRI (image fusion based on mutual information). Results: The correlation between gross tumor volume (GTVs) delineated by the two observers based on CT/MRI was r = 0.855 (Spearman's correlation coefficient, p = 0.002) and r = 0.988 (p = 0.000) when MET-PET/CT/MRI were used. The number of patients with agreement in more then 80% of the outlined volume increased with the availability of MET-PET from 1 in 10 to 5 in 10. The median volume of intersection between the regions delineated by two observers increased significantly from 69% (from the composite volume) to 79%, by the addition of MET-PET (p = 0.005). The information of MET-PET was useful to delineate GTV in the area of cavernous sinus, orbit, and base of the skull. Conclusions: The hypothesis-generating findings of potential normal tissue sparing and reduced interobserver variability provide arguments for invasive studies of the correlation between MET-PET images and histologic tumor extension and for prospective trials of target volume delineation with CT/MRI/MET-PET image fusion.

  2. A plasmacytoid dendritic cell (CD123+/CD11c-) based assay system to predict contact allergenicity of chemicals

    PubMed Central

    Ayehunie, Seyoum; Snell, Maureen; Child, Matthew; Klausner, Mitchell

    2009-01-01

    A predictive allergenicity test system for assessing the contact allergenicity of chemicals is needed by the cosmetic and pharmaceutical industry to monitor product safety in the marketplace. Development of such non-animal alternative assay systems for skin sensitization and hazard identification has been pursued by policy makers and regulatory agencies. We investigated whether phenotypic and functional changes to a subset of dendritic cells (DC), plasmacytoid DC (pDC), could be used to identify contact allergens. To achieve this goal, normal human DC were generated from CD34+ progenitor cells and cryopreserved. Frozen DC were thawed and the pDC fraction (CD123+/CD11c-) was harvested using FACS sorting. The pDC were cultured, expanded, and exposed to chemical allergens (N=26) or non-allergens (N=22). Concentrations of each chemical that resulted in >50% viability was determined using FACS analysis of propidium iodide stained cells using pDC from 2-5 donors. Expression of the surface marker, CD86, which has been implicated in dendritic cell maturation, was used as a marker of allergenicity. CD86 expression increased (≥ 1.5 fold) for 25 of 26 allergens (sensitivity = 96%) but did not increase for 19 of 22 non-allergens (specificity = 86%). In a direct comparison to historical data for the regulatory approved, mouse local lymph node assay (LLNA) for 23 allergens and 22 non-allergens, the pDC method had sensitivity and specificity of 96% and 86%, respectively, while the sensitivity and specificity of the LLNA assay was 83% and 82%, respectively. In conclusion, CD86 expression in pDC appears to be a sensitive and specific indicator to identify contact allergenicity. Such an assay method utilizing normal human cells will be useful for high throughput screening of chemicals for allergenicity. PMID:19665512

  3. Nonuniform Cardiac Denervation Observed by 11C-meta-Hydroxyephedrine PET in 6-OHDA-Treated Monkeys

    PubMed Central

    Joers, Valerie; Seneczko, Kailie; Goecks, Nichole C.; Kamp, Timothy J.; Hacker, Timothy A.; Brunner, Kevin G.; Engle, Jonathan W.; Barnhart, Todd E.; Nickles, R. Jerome; Holden, James E.; Emborg, Marina E.

    2012-01-01

    Parkinson's disease presents nonmotor complications such as autonomic dysfunction that do not respond to traditional anti-parkinsonian therapies. The lack of established preclinical monkey models of Parkinson's disease with cardiac dysfunction hampers development and testing of new treatments to alleviate or prevent this feature. This study aimed to assess the feasibility of developing a model of cardiac dysautonomia in nonhuman primates and preclinical evaluations tools. Five rhesus monkeys received intravenous injections of 6-hydroxydopamine (total dose: 50 mg/kg). The animals were evaluated before and after with a battery of tests, including positron emission tomography with the norepinephrine analog 11C-meta-hydroxyephedrine. Imaging 1 week after neurotoxin treatment revealed nearly complete loss of specific radioligand uptake. Partial progressive recovery of cardiac uptake found between 1 and 10 weeks remained stable between 10 and 14 weeks. In all five animals, examination of the pattern of uptake (using Logan plot analysis to create distribution volume maps) revealed a persistent region-specific significant loss in the inferior wall of the left ventricle at 10 (P<0.001) and 14 weeks (P<0.01) relative to the anterior wall. Blood levels of dopamine, norepinephrine (P<0.05), epinephrine, and 3,4-dihydroxyphenylacetic acid (P<0.01) were notably decreased after 6-hydroxydopamine at all time points. These results demonstrate that systemic injection of 6-hydroxydopamine in nonhuman primates creates a nonuniform but reproducible pattern of cardiac denervation as well as a persistent loss of circulating catecholamines, supporting the use of this method to further develop a monkey model of cardiac dysautonomia. PMID:22539969

  4. Nanostructured copper, chromium, and tin oxide multicomponent materials as catalysts for methanol decomposition: 11C-radiolabeling study.

    PubMed

    Tsoncheva, Tanya; Sarkadi-Priboczki, Eva; Dimitrov, Momtchil; Genova, Izabela

    2013-01-01

    Copper and chromium modified tin oxide nanocomposites were obtained via incipient wetness impregnation of high surface area nanosized SnO(2) with the corresponding metal acetylacetonates and their further decomposition in air. Powder X-ray diffraction (XRD), Nitrogen physisorption, UV-Vis, and Temperature-programmed reduction (TPR) with hydrogen were applied for the samples characterization. The catalytic activity of the obtained materials was tested in methanol conversion. A new approach based on the selective coverage of the surface with (11)C-methanol was used for the characterization of the catalytic sites. It was demonstrated that the products distribution could be controlled by the surface coverage with methanol and the role of different active sites was discussed. The modification of SnO(2) with copper oxide increased the activity in methanol decomposition to CO(2)via dioxymethylene intermediates, but the catalyst suffered considerable loss of activity due to the reduction transformations by the reaction medium and formation of an inactive intermetallic alloy. The modification with chromium changed the acid-basic properties of SnO(2) by the formation of Cr(2)O(3) nanoparticles as well as anchored to the support chromate species. The former particles facilitated the formation of dimethyl ether (DME), while the latter species converted methanol predominantly to hydrocarbons. The fraction of chromate species increased in Cu-Cr-Sn oxide multicomponent nanocomposites and promoted the formation of hydrocarbons over DME at low temperatures, while at higher temperatures, the activity of the copper species leading to CO(2) formation was more pronounced. PMID:23031492

  5. Nonuniform cardiac denervation observed by 11C-meta-hydroxyephedrine PET in 6-OHDA-treated monkeys.

    PubMed

    Joers, Valerie; Seneczko, Kailie; Goecks, Nichole C; Kamp, Timothy J; Hacker, Timothy A; Brunner, Kevin G; Engle, Jonathan W; Barnhart, Todd E; Nickles, R Jerome; Holden, James E; Emborg, Marina E

    2012-01-01

    Parkinson's disease presents nonmotor complications such as autonomic dysfunction that do not respond to traditional anti-parkinsonian therapies. The lack of established preclinical monkey models of Parkinson's disease with cardiac dysfunction hampers development and testing of new treatments to alleviate or prevent this feature. This study aimed to assess the feasibility of developing a model of cardiac dysautonomia in nonhuman primates and preclinical evaluations tools. Five rhesus monkeys received intravenous injections of 6-hydroxydopamine (total dose: 50 mg/kg). The animals were evaluated before and after with a battery of tests, including positron emission tomography with the norepinephrine analog (11)C-meta-hydroxyephedrine. Imaging 1 week after neurotoxin treatment revealed nearly complete loss of specific radioligand uptake. Partial progressive recovery of cardiac uptake found between 1 and 10 weeks remained stable between 10 and 14 weeks. In all five animals, examination of the pattern of uptake (using Logan plot analysis to create distribution volume maps) revealed a persistent region-specific significant loss in the inferior wall of the left ventricle at 10 (P<0.001) and 14 weeks (P<0.01) relative to the anterior wall. Blood levels of dopamine, norepinephrine (P<0.05), epinephrine, and 3,4-dihydroxyphenylacetic acid (P<0.01) were notably decreased after 6-hydroxydopamine at all time points. These results demonstrate that systemic injection of 6-hydroxydopamine in nonhuman primates creates a nonuniform but reproducible pattern of cardiac denervation as well as a persistent loss of circulating catecholamines, supporting the use of this method to further develop a monkey model of cardiac dysautonomia. PMID:22539969

  6. Sea surface temperature and salinity patterns in the northern North Atlantic and the Arctic during interglacial MIS 11c: Implications for oceanic circulation reconstruction

    NASA Astrophysics Data System (ADS)

    Kandiano, E.; van der Meer, M.; Schouten, S.; Fahl, K.; Polyak, L. V.; Cronin, T. M.; Bauch, H. A.; Sinninghe Damste, J. S.

    2013-12-01

    Sea surface temperature (SST) patterns in the northern North Atlantic, the Nordic seas, and the western Arctic Ocean (AO) were reconstructed across the MIS 11c interglacial, a potential future climate analogue, using planktic foraminiferal abundances, alkenone-based Uk'37 and glycerol dialkyl glycerol tetraether (GDGT)-based TEX86 analyses. Foraminiferal SST reconstructions were supported by foraminiferal counts of small-sized fractions and rare foraminiferal species, stable oxygen isotope measurements on benthic and planktic foraminifers, and ice rafted debris records. Additionally, the hydrogen isotopic (δD) compositions of long chain alkenones were determined to assess variations in paleo sea surface salinity in the North Atlantic. In the North Atlantic our newly produced TEX86 -based SSTs range between 14 and 19 °C in agreement with summer foraminiferal SST (13 and 18 °C) and alkenone SSTs (13 and 16 °C). However, the former showed higher fluctuations than SSTs based on foraminiferal abundances. In concordance with δ18O records TEX86 SSTs demonstrate notable variability in the middle of MIS 11c, between 400 and 410 ka, which is consistent with the intra-MIS 11c cold event in the Arctic indicated by planktic foraminifers. This pattern implies that the interglacial MIC 11c climate was probably not as stable as it widely believed. The preliminary alkenone δD data show that during MIS 11c salinity values in the North Atlantic were similar to Holocene values. Foraminiferal SST records imply that during MIS 11c at least parts of the AO experienced unusually warm and probably ice free conditions, whereas the Nordic seas remained rather cold, especially during the early phase of this period, as it is inferred from foraminiferal and alkenone SSTs. At the same time all our SST records show that the North Atlantic was 1-2°C warmer than present during MIS 11c. This pattern suggests that during MIS 11c the North Atlantic Current was deflected to the west, which

  7. Brain and Whole-Body Imaging of Nociceptin/Orphanin FQ Peptide Receptor in Humans Using the PET Ligand 11C-NOP-1A

    PubMed Central

    Lohith, Talakad G.; Zoghbi, Sami S.; Morse, Cheryl L.; Araneta, Maria F.; Barth, Vanessa N.; Goebl, Nancy A.; Tauscher, Johannes T.; Pike, Victor W.; Innis, Robert B.; Fujita, Masahiro

    2013-01-01

    Nociceptin/orphanin FQ peptide (NOP) receptor is a new class of opioid receptor that may play a pathophysiologic role in anxiety and drug abuse and is a potential therapeutic target in these disorders. We previously developed a high-affinity PET ligand, 11C-NOP-1A, which yielded promising results in monkey brain. Here, we assessed the ability of 11C-NOP-1A to quantify NOP receptors in human brain and estimated its radiation safety profile. Methods After intravenous injection of 11C-NOP-1A, 7 healthy subjects underwent brain PET for 2 h and serial sampling of radial arterial blood to measure parent radioligand concentrations. Distribution volume (VT; a measure of receptor density) was determined by compartmental (1- and 2-tissue) and noncompartmental (Logan analysis and Ichise’s bilinear analysis [MA1]) methods. A separate group of 9 healthy subjects underwent whole-body PET to estimate whole-body radiation exposure (effective dose). Results After 11C-NOP-1A injection, the peak concentration of radioactivity in brain was high (~5–7 standardized uptake values), occurred early (~10 min), and then washed out quickly. The unconstrained 2-tissue-compartment model gave excellent VT identifiability (~1.1% SE) and fitted the data better than a 1-tissue-compartment model. Regional VT values (mL·cm−3) ranged from 10.1 in temporal cortex to 5.6 in cerebellum. VT was well identified in the initial 70 min of imaging and remained stable for the remaining 50 min, suggesting that brain radioactivity was most likely parent radioligand, as supported by the fact that all plasma radiometabolites of 11C-NOP-1A were less lipophilic than the parent radioligand. Voxel-based MA1 VT values correlated well with results from the 2-tissue-compartment model, showing that parametric methods can be used to compare populations. Whole-body scans showed radioactivity in brain and in peripheral organs expressing NOP receptors, such as heart, pancreas, and spleen. 11C-NOP-1A was significantly

  8. 11C-choline vs. 18F-FDG PET/CT in assessing bone involvement in patients with multiple myeloma

    PubMed Central

    Nanni, Cristina; Zamagni, Elena; Cavo, Michele; Rubello, Domenico; Tacchetti, Paola; Pettinato, Cinzia; Farsad, Mohsen; Castellucci, Paolo; Ambrosini, Valentina; Montini, Gian Carlo; Al-Nahhas, Adil; Franchi, Roberto; Fanti, Stefano

    2007-01-01

    Background Multiple Myeloma (MM) is a B cell neoplasm causing lytic or osteopenic bone abnormalities. Whole body skeletal survey (WBSS), Magnetic resonance (MR) and 18F-FDG PET/CT are imaging techniques routinely used for the evaluation of bone involvement in MM patients. Aim As MM bone lesions may present low 18F-FDG uptake; the aim of this study was to assess the possible added value and limitations of 11C-Choline to that of 18F-FDG PET/CT in patients affected with MM. Methods Ten patients affected with MM underwent a standard 11C-Choline PET/CT and an 18F-FDG PET/CT within one week. The results of the two scans were compared in terms of number, sites and SUVmax of lesions. Results Four patients (40%) had a negative concordant 11C-Choline and 18F-FDG PET/CT scans. Two patients (20%) had a positive 11C-Choline and 18F-FDG PET/CT scans that identified the same number and sites of bone lesions. The remaining four patients (40%) had a positive 11C-Choline and 18F-FDG PET/CT scan, but the two exams identified different number of lesions. Choline showed a mean SUVmax of 5 while FDG showed a mean SUVmax of 3.8 (P = 0.042). Overall, 11C-Choline PET/CT scans detected 37 bone lesions and 18F-FDG PET/CT scans detected 22 bone lesions but the difference was not significant (P = 0.8). Conclusion According to these preliminary data, 11C-Choline PET/CT appears to be more sensitive than 18F-FDG PET/CT for the detection of bony myelomatous lesions. If these data are confirmed in larger series of patients, 11C-Choline may be considered a more appropriate functional imaging in association with MRI for MM bone staging. PMID:17584499

  9. a Coupled GCM Comparison of Marine Isotope Stages 1, 5e, 11c and 31 IN Relation to Lake El'gygytgyn, NE Russia

    NASA Astrophysics Data System (ADS)

    Coletti, A. J.; DeConto, R.; Melles, M.; Brigham-Grette, J.; Minyuk, P.

    2012-12-01

    The lack of scientific data concerning interglacials of the Pleistocene in the Arctic has been a major obstacle within the climate community. Study of the interglacials of Marine Isotope Stage(s) (MIS) 1, 5e, 11c and 31 in high latitudes is important to decoding Arctic sensitivity and providing us with a potential analogue for a future Arctic with climate change. Data from a sediment core recovered from Lake El'Gygytgyn in northeastern (NE) Russia gives a continuous, high-resolution record of the Arctic spanning the past 2.8 million years whilst recording these interglacials. The data was used to correlate simulated interglacial Arctic climate with Arctic climate derived from sediment core proxy studies. Here, we use a Global Circulation Model (GCM) with a coupled atmosphere and land-surface scheme complete with an interactive vegetation component to simulate marine isotope stages 1, 5e, 11c and 31 in the Arctic. GCM simulations of MIS 5e and 31 in the Arctic both show a warmer arctic climate that can be explained by high obliquity, high eccentricity, high CO2 (287 ppmv ,325 ppmv , respectively) and precession that aligns perihelion with boreal summer. Consequently, MIS 5e showed the greatest summer warming compared to the other interglacials and pre-industrial control. However, the distinctly higher values of mean temperature of the warmest month (MTWM) and annual precipitation during stage 11c cannot readily be explained by summer orbital forcings and greenhouse gas (GHG) concentrations. Montane forest is seen migrating northward in stages 1, 5e and 31 as the surface insolation increases and sea ice melts, whereas in 11c, the warmest of the interglacials, evergreen forest takes over and migrates pole ward toward the coast. Feedback from low albedo forest biome was studied and conclusions suggest the increase in temperature due to forest cover is insignificant in creating a significantly warm regional climate. The warming associated with a lack of a Greenland Ice

  10. Relevance of a scoring system including CD11c expression in the identification of splenic diffuse red pulp small B-cell lymphoma (SRPL).

    PubMed

    Baseggio, L; Traverse-Glehen, A; Callet-Bauchu, E; Morel, D; Magaud, J P; Berger, F; Salles, G; Felman, P

    2011-03-01

    'Splenic red pulp lymphoma with numerous basophilic villous lymphocytes' (SRPL), recently described, is characterized by clinical, morphologic, immunologic, cytogenetic and molecular features distinct from SMZL/SLVL and HCL. In particular, the intensity of CD11c staining (expressed as fluorescence intensity -RFI-) in SRPL is significantly different from the RFI in SMZL/SLVL and HCL. Moreover the use of a scoring system based on the expression of CD11c, CD22, CD76, CD38 and CD27 appears to improve the differential diagnosis between SRPL and SMZL/SLVL and emphasizes that SRPL is an entity closed to but distinct from SMZL/SLVL. PMID:20677173

  11. PDT in the thoracic cavity: Spectroscopic methods and fluence modeling for treatment planning

    NASA Astrophysics Data System (ADS)

    Meo, Julia Lauren

    PDT for the thoracic cavity provides a promising cancer treatment modality, but improvements in treatment planning, particularly in PDT dosimetry, can be made to improve uniformity of light delivery. When a cavity of arbitrary geometry is illuminated, the fluence increases due to multiple-scattered photons, referred to as the Integrating Sphere Effect (ISE). Current pleural PDT treatment protocol at the University of Pennsylvania monitors light fluence (hereafter simply fluence, measured in W/cm2) via seven isotropic detectors sutured at different locations in thoracic cavity of a patient. This protocol monitors light at discrete locations, but does not provide a measurement of fluence for the thoracic cavity as a whole. Current calculation of light fluence includes direct light only and thus does not account for the unique optical properties of each tissue type present, which in turn affects the accuracy of the calculated light distribution in the surrounding tissue and, in turn, the overall cell death and treatment efficacy. Treatment planning for pleural PDT can be improved, in part, by considering the contribution of scattered light, which is affected by the two factors of geometry and in vivo optical properties. We expanded the work by Willem Star in regards to the ISE in a spherical cavity. A series of Monte Carlo (MC) simulations were run for semi-infinite planar, spherical, and ellipsoidal geometries for a range of optical properties. The results of these simulations are compared to theory and numerical solutions for fluence in the cavity and at the cavity-medium boundary. The development via MC simulations offers a general method of calculating the required light fluence specialized to each patient, based on the treatment surface area. The scattered fluence calculation is dependent on in vivo optical properties (μa and μs') of the tissues treated. Diffuse reflectance and fluorescence spectroscopy methods are used to determine the optical properties and

  12. Femtosecond laser ablation of dentin and enamel: relationship between laser fluence and ablation efficiency

    NASA Astrophysics Data System (ADS)

    Chen, Hu; Liu, Jing; Li, Hong; Ge, Wenqi; Sun, Yuchun; Wang, Yong; Lü, Peijun

    2015-02-01

    The objective was to study the relationship between laser fluence and ablation efficiency of a femtosecond laser with a Gaussian-shaped pulse used to ablate dentin and enamel for prosthodontic tooth preparation. A diode-pumped thin-disk femtosecond laser with wavelength of 1025 nm and pulse width of 400 fs was used for the ablation of dentin and enamel. The laser spot was guided in a line on the dentin and enamel surfaces to form a groove-shaped ablation zone under a series of laser pulse energies. The width and volume of the ablated line were measured under a three-dimensional confocal microscope to calculate the ablation efficiency. Ablation efficiency for dentin reached a maximum value of 0.020 mm3/J when the laser fluence was set at 6.51 J/cm2. For enamel, the maximum ablation efficiency was 0.009 mm3/J at a fluence of 7.59 J/cm2. Ablation efficiency of the femtosecond laser on dentin and enamel is closely related to the laser fluence and may reach a maximum when the laser fluence is set to an appropriate value.

  13. Mechanical Behaviour of Cyanate Ester/epoxy Blends after Reactor Irradiation to High Neutron Fluences

    NASA Astrophysics Data System (ADS)

    Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.

    2008-03-01

    The mechanical strength of conventional epoxy resins drops dramatically after irradiation to a fast neutron fluence of 1×1022 m-2 (E>0.1 MeV). Recent results demonstrated that cyanate ester/epoxy blends were not affected at this fluence level. The aim of this study is to investigate the performance potential of these blends at higher fluence levels without significant degradation of their mechanical properties. Short-beam shear as well as static tensile tests were carried out at 77 K prior to and after irradiation to fast neutron fluences of up to 4×1022 m-2 (E>0.1 MeV) in the TRIGA reactor at ambient temperature (340 K). In addition, load controlled tension-tension fatigue measurements were performed, in order to simulate the pulsed operation conditions of a tokamak. Initial results show that only a small reduction of the mechanical strength under static and dynamic load is observed at a fast neutron fluence of 2×1022 m-2 (E>0.1 MeV). After exposure to 4×1022 m-2 (E>0.1 MeV) the interlaminar shear strength of materials with a cyanate ester content of 40% or more is only reduced by 20% to 30%.

  14. Equivalent electron fluence for solar proton damage in GaAs shallow junction cells

    NASA Astrophysics Data System (ADS)

    Wilson, J. W.; Stock, L. V.

    The short-circuit current reduction in GaAs shallow junction heteroface solar cells was calculated according to a simplified solar cell damage model in which the nonuniformity of the damage as a function of penetration depth is treated explicitly. Although the equivalent electron fluence was not uniquely defined for low-energy monoenergetic proton exposure, an equivalent electron fluence is found for proton spectra characteristic of the space environment. The equivalent electron fluence ratio was calculated for a typical large solar flare event for which the proton spectrum is PHI(sub p)(E) = A/E(p/sq. cm) where E is in MeV. The equivalent fluence ratio is a function of the cover glass shield thickness or the corresponding cutoff energy E(sub c). In terms of the cutoff energy, the equivalent 1 MeV electron fluence ratio is r(sub p)(E sub c) = 10(9)/E(sub c)(1.8) where E(sub c) is in units of KeV.

  15. Equivalent electron fluence for solar proton damage in GaAs shallow junction cells

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Stock, L. V.

    1984-01-01

    The short-circuit current reduction in GaAs shallow junction heteroface solar cells was calculated according to a simplified solar cell damage model in which the nonuniformity of the damage as a function of penetration depth is treated explicitly. Although the equivalent electron fluence was not uniquely defined for low-energy monoenergetic proton exposure, an equivalent electron fluence is found for proton spectra characteristic of the space environment. The equivalent electron fluence ratio was calculated for a typical large solar flare event for which the proton spectrum is PHI(sub p)(E) = A/E(p/sq. cm) where E is in MeV. The equivalent fluence ratio is a function of the cover glass shield thickness or the corresponding cutoff energy E(sub c). In terms of the cutoff energy, the equivalent 1 MeV electron fluence ratio is r(sub p)(E sub c) = 10(9)/E(sub c)(1.8) where E(sub c) is in units of KeV.

  16. Coupling of Monte Carlo adjoint leakages with three-dimensional discrete ordinates forward fluences

    SciTech Connect

    Slater, C.O.; Lillie, R.A.; Johnson, J.O.; Simpson, D.B.

    1998-04-01

    A computer code, DRC3, has been developed for coupling Monte Carlo adjoint leakages with three-dimensional discrete ordinates forward fluences in order to solve a special category of geometrically-complex deep penetration shielding problems. The code extends the capabilities of earlier methods that coupled Monte Carlo adjoint leakages with two-dimensional discrete ordinates forward fluences. The problems involve the calculation of fluences and responses in a perturbation to an otherwise simple two- or three-dimensional radiation field. In general, the perturbation complicates the geometry such that it cannot be modeled exactly using any of the discrete ordinates geometry options and thus a direct discrete ordinates solution is not possible. Also, the calculation of radiation transport from the source to the perturbation involves deep penetration. One approach to solving such problems is to perform the calculations in three steps: (1) a forward discrete ordinates calculation, (2) a localized adjoint Monte Carlo calculation, and (3) a coupling of forward fluences from the first calculation with adjoint leakages from the second calculation to obtain the response of interest (fluence, dose, etc.). A description of this approach is presented along with results from test problems used to verify the method. The test problems that were selected could also be solved directly by the discrete ordinates method. The good agreement between the DRC3 results and the direct-solution results verify the correctness of DRC3.

  17. Microstructural interpretation of the fluence and temperature dependence of the mechanical properties of irradiated AISI 316

    SciTech Connect

    Johnson, G.D.; Garner, F.A.; Brager, H.R.; Fish, R.L.

    1980-04-17

    The effects of neutron irradiation on the mechanical properties of annealed and 20% cold-worked AISI 316 irradiated in EBR-II were determined for the temperature regime of 370 to 760/sup 0/C for fluences up to 8.4 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). At irradiation temperatures below about 500/sup 0/C, both annealed and cold-worked material exhibit a substantial increase in the flow stress with increasing fluence. Furthermore, both materials eventually exhibit the same flow stress, which is independent of fluence. At temperatures in the range of 538 to 650/sup 0/C, the cold-worked material exhibits a softening with increasing fluence. Annealed AISI 316 in this temperature regime exhibits hardening and at a fluence of 2 to 3 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV) reaches the same value of flow stress as the cold-worked material.

  18. MECHANICAL BEHAVIOUR OF CYANATE ESTER/EPOXY BLENDS AFTER REACTOR IRRADIATION TO HIGH NEUTRON FLUENCES

    SciTech Connect

    Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.

    2008-03-03

    The mechanical strength of conventional epoxy resins drops dramatically after irradiation to a fast neutron fluence of 1x10{sup 22} m{sup -2} (E>0.1 MeV). Recent results demonstrated that cyanate ester/epoxy blends were not affected at this fluence level. The aim of this study is to investigate the performance potential of these blends at higher fluence levels without significant degradation of their mechanical properties. Short-beam shear as well as static tensile tests were carried out at 77 K prior to and after irradiation to fast neutron fluences of up to 4x10{sup 22} m{sup -2} (E>0.1 MeV) in the TRIGA reactor at ambient temperature (340 K). In addition, load controlled tension-tension fatigue measurements were performed, in order to simulate the pulsed operation conditions of a tokamak. Initial results show that only a small reduction of the mechanical strength under static and dynamic load is observed at a fast neutron fluence of 2x10{sup 22} m{sup -2} (E>0.1 MeV). After exposure to 4x10{sup 22} m{sup -2} (E>0.1 MeV) the interlaminar shear strength of materials with a cyanate ester content of 40% or more is only reduced by 20% to 30%.

  19. Comparison of [11C]cocaine binding at tracer and pharmacological doses of baboon brain: A PET study

    SciTech Connect

    Volkow, N.D.; Fowler, J.S.; Logan, J.

    1994-05-01

    In vitro studies have shown that cocaine (C) binds to both high and low affinity sites on the dopamine transporter (DAT). We have previously characterized the binding of tracer doses of [{sup 11}C]cocaine (C*)to a high affinity site on the DAT. To assess if in vivo C also binds to low affinity sites we used PET to compare binding of tracer doses (17.8{plus_minus}12.2 {mu}g C) of C* to pharmacological doses (8 mg of C coadministered with C*). Sixteen paired studies were done to assess test/retest variability, specific versus non specific binding and to characterize binding profile. Dynamic scans were started immediately after injection of C* (5-8 mCi) for 50 min on the CTI-931 (6 x 6 x 6.5 mm FWHM). Time activity curves for tissue concentration and for unchanged tracer in plasma were used to calculate the transport constant between plasma and tissue (K1) and to obtain the distribution volume (DV). The ratio of the DV in striatum (ST) to that in cerebellum (CB) (which corresponds to Bmax/Kd-1) was used as model parameter. Peak brain uptake of C* was significantly higher for tracer than for pharmacological doses (0.041 versus 0.033 % dose/cc), as were the values for K1 (1.07{plus_minus}0.21 versus 0.68{plus_minus}0.26 (t=3.0 p<0.01)). Repeated measures were reproducible for tracer ({plus_minus}2%) and pharmacological doses of C* ({plus_minus}4%). Tracer dose C* showed highest binding and slowest clearance in ST which was reduced by C (0.5-2.0 mg/kg iv, -25 to -30%) and by drugs that inhibit DAT (2mg/kg nomifensine - 21%, 0.5 mg/kg methylphenidate -12%) and was increased by serotonin transporter inhibitors (5HT-Ti) (2 mg/kg citalopram +11%, 0.5 mg/kg fluoxetine +6%) and not changed by NE transporter inhibitors (0.5 mg/kg desipramine or 2 mg/kg tomoxetine). The increase with (5HT-Ti) may reflect neurotransmitter interactions or changes in bioavailability. At pharmacological doses C* showed homogeneous distribution and was not changed by C nor by any of the above drugs.

  20. A case of mistaken identity: CD11c-eYFP(+) cells in the normal mouse brain parenchyma and neural retina display the phenotype of microglia, not dendritic cells.

    PubMed

    Dando, Samantha J; Naranjo Golborne, Cecilia; Chinnery, Holly R; Ruitenberg, Marc J; McMenamin, Paul G

    2016-08-01

    Under steady-state conditions the central nervous system (CNS) is traditionally thought to be devoid of antigen presenting cells; however, putative dendritic cells (DCs) expressing enhanced yellow fluorescent protein (eYFP) are present in the retina and brain parenchyma of CD11c-eYFP mice. We previously showed that these mice carry the Crb1(rd8) mutation, which causes retinal dystrophic lesions; therefore we hypothesized that the presence of CD11c-eYFP(+) cells within the CNS may be due to pathology associated with the Crb1(rd8) mutation. We generated CD11c-eYFP Crb1(wt/wt) mice and compared the distribution and immunophenotype of CD11c-eYFP(+) cells in CD11c-eYFP mice with and without the Crb1(rd8) mutation. The number and distribution of CD11c-eYFP(+) cells in the CNS was similar between CD11c-eYFP Crb1(wt/wt) and CD11c-eYFP Crb1(rd8/rd8) mice. CD11c-eYFP(+) cells were distributed throughout the inner retina, and clustered in brain regions that receive input from the external environment or lack a blood-brain barrier. CD11c-eYFP(+) cells within the retina and cerebral cortex of CD11c-eYFP Crb1(wt/wt) mice expressed CD11b, F4/80, CD115 and Iba-1, but not DC or antigen presentation markers, whereas CD11c-eYFP(+) cells within the choroid plexus and pia mater expressed CD11c, I-A/I-E, CD80, CD86, CD103, DEC205, CD8α and CD135. The immunophenotype of CD11c-eYFP(+) cells and microglia within the CNS was similar between CD11c-eYFP Crb1(wt/wt) and CD11c-eYFP Crb1(rd8/rd8) mice; however, CD11c and I-A/I-E expression was significantly increased in CD11c-eYFP Crb1(rd8/rd8) mice. This study demonstrates that the overwhelming majority of CNS CD11c-eYFP(+) cells do not display the phenotype of DCs or their precursors and are most likely a subpopulation of microglia. GLIA 2016. GLIA 2016;64:1331-1349. PMID:27189804

  1. Synthesis and biodistribution of [11C]A-836339, a new potential radioligand for PET imaging of cannabinoid type 2 receptors (CB2)

    PubMed Central

    Horti, Andrew G.; Gao, Yongjun; Ravert, Hayden T.; Finley, Paige; Valentine, Heather; Wong, Dean F.; Endres, Christopher J.; Savonenko, Alena V.; Dannals, Robert F.

    2010-01-01

    Recently, A-836339 [2,2,3,3-tetramethylcyclopropanecarboxylic acid [3-(2-methoxyethyl)-4,5-dimethyl-3H-thiazol-(2Z)-ylidene]amide] (1) was reported to be a selective CB2 agonist with high binding affinity. Here we describe the radiosynthesis of [11C]A-836339 ([11C]1) via its desmethyl precursor as a candidate radioligand for imaging CB2 receptors with positron emission tomography (PET). Whole body and the regional brain distribution of [11C]1 in control CD1 mice demonstrated that this radioligand exhibits specific uptake in the CB2-rich spleen and little specific in vivo binding in the control mouse brain. However, [11C]1 shows specific cerebral uptake in the lipopolysaccharide (LPS)-induced mouse model of neuroinflammation and in the brain areas with Aβ-amyloid plaque deposition in a mouse model of Alzheimer's disease (APPswe/PS1dE9 mice). These data establish a proof of principle that CB2 receptors binding in the neuroinflammation and related disorders can be measured in vivo. PMID:20554448

  2. Direct one-step labeling of cysteine residues on peptides with [(11)C]methyl triflate for the synthesis of PET radiopharmaceuticals.

    PubMed

    Chin, Joshua; Vesnaver, Matthew; Bernard-Gauthier, Vadim; Saucke-Lacelle, Erin; Wängler, Björn; Wängler, Carmen; Schirrmacher, Ralf

    2013-11-01

    Radiolabeled peptides have emerged as an attractive platform for the diagnostic and therapeutic oncology. However, the (11)C-radiolabeling of peptides for positron emission tomography (PET) has been poorly explored, owing to the relatively short half-life of carbon-11 (t 1/2 = 20.3 min) and time-consuming multi-step radiochemical reactions. Existing methods have found limited use and are not routinely encountered in the production of radiotracers. Herein, we propose a facile one-step direct (11)C-methylation of cysteine residues in peptides using [(11)C]methyl triflate under ambient temperatures (20 °C) and short reaction times, on the order of seconds. Good regioselectivity of this method was demonstrated by HPLC in a simple peptide (glutathione, GSH) and a more complex test decapeptide (Trp-Tyr-Trp-Ser-Arg-Cys-Lys-Trp-Thr-Gly) bearing multiple nucleophilic sites. In addition, we extend this method towards the synthesis of [(11)C]Cys(Me)-[Tyr(3)-octreotate] as a demonstration of applicability for peptides of biological interest. This octreotate derivative was obtained in non-decay-corrected radiochemical yields of 11 ± 2 % (n = 3) with a synthesis time of approx. 30 min. PMID:23921782

  3. Cutting Edge: IL-4, IL-21, and IFN-γ Interact To Govern T-bet and CD11c Expression in TLR-Activated B Cells.

    PubMed

    Naradikian, Martin S; Myles, Arpita; Beiting, Daniel P; Roberts, Kenneth J; Dawson, Lucas; Herati, Ramin Sedaghat; Bengsch, Bertram; Linderman, Susanne L; Stelekati, Erietta; Spolski, Rosanne; Wherry, E John; Hunter, Christopher; Hensley, Scott E; Leonard, Warren J; Cancro, Michael P

    2016-08-15

    T-bet and CD11c expression in B cells is linked with IgG2c isotype switching, virus-specific immune responses, and humoral autoimmunity. However, the activation requisites and regulatory cues governing T-bet and CD11c expression in B cells remain poorly defined. In this article, we reveal a relationship among TLR engagement, IL-4, IL-21, and IFN-γ that regulates T-bet expression in B cells. We find that IL-21 or IFN-γ directly promote T-bet expression in the context of TLR engagement. Further, IL-4 antagonizes T-bet induction. Finally, IL-21, but not IFN-γ, promotes CD11c expression independent of T-bet. Using influenza virus and Heligmosomoides polygyrus infections, we show that these interactions function in vivo to determine whether T-bet(+) and CD11c(+) B cells are formed. These findings suggest that T-bet(+) B cells seen in health and disease share the common initiating features of TLR-driven activation within this circumscribed cytokine milieu. PMID:27430719

  4. Comparative double-tracer whole-body autoradiography: uptake of 11C-, 18F- and 3H-labeled compounds in rat tumors.

    PubMed

    d'Argy, R; Paul, R; Frankenberg, L; Stålnacke, C G; Lundqvist, H; Kangas, L; Halldin, C; Någren, K; Roeda, D; Haaparanta, M

    1988-01-01

    The uptake of various labeled compounds by tumors was studied by double-tracer whole-body autoradiography (DTWBA) in rats. Each animal carried two types of tumors: mammary carcinomas and the Walker 256 carcinosarcomas. The markers used were [18F]- and [3H]fluorodeoxyglucose (glucose utilization), [3H]thymidine (cell proliferation), [11C]methionine (amino acid metabolism) and [11C]- and [3H]toremifene (estrogen-receptor-avid agents). In each experiment, the distribution of a substance labeled with short-lived radionuclide (11C or 18F) was compared with that of another substance labeled with a long-lived nuclide (3H). Quantification was done by combining computerized image analysis of the autoradiograms with liquid scintillation counting of punched tissue pieces obtained from the cryosections. The relationships between the uptakes of the various radiopharmaceuticals were recorded in tumors and normal tissues. The dynamics of [18F]fluorodeoxyglucose and [11C]methionine were determined in tumors and some selected tissues by positron emission tomography (PET). The uptake rate between fluorodeoxyglucose and thymidine in the mammary tumor was five times higher than the ratio in the Walker tumor. The corresponding figure for FDG/methionine was four times. Thymidine, compared with methionine, was twice as efficient. Thus, the mammary tumors were best imaged with FDG or thymidine. The non-steroid antiestrogen toremifene was taken up in very low amounts by these tumors. By DTWBA, experimental tumors may serve as their own control. PMID:2978293

  5. Improved ion implant fluence uniformity in hydrogen enhanced glow discharge plasma immersion ion implantation into silicon.

    PubMed

    Luo, J; Li, L H; Liu, H T; Yu, K M; Xu, Y; Zuo, X J; Zhu, P Z; Ma, Y F; Fu, Ricky K Y; Chu, Paul K

    2014-06-01

    Enhanced glow discharge plasma immersion ion implantation does not require an external plasma source but ion focusing affects the lateral ion fluence uniformity, thereby hampering its use in high-fluence hydrogen ion implantation for thin film transfer and fabrication of silicon-on-insulator. Insertion of a metal ring between the sample stage and glass chamber improves the ion uniformity and reduces the ion fluence non-uniformity as the cathode voltage is raised. Two-dimensional multiple-grid particle-in-cell simulation confirms that the variation of electric field inside the chamber leads to mitigation of the ion focusing phenomenon and the results are corroborated experimentally by hydrogen forward scattering. PMID:24985818

  6. Improved ion implant fluence uniformity in hydrogen enhanced glow discharge plasma immersion ion implantation into silicon

    NASA Astrophysics Data System (ADS)

    Luo, J.; Li, L. H.; Liu, H. T.; Yu, K. M.; Xu, Y.; Zuo, X. J.; Zhu, P. Z.; Ma, Y. F.; Fu, Ricky K. Y.; Chu, Paul K.

    2014-06-01

    Enhanced glow discharge plasma immersion ion implantation does not require an external plasma source but ion focusing affects the lateral ion fluence uniformity, thereby hampering its use in high-fluence hydrogen ion implantation for thin film transfer and fabrication of silicon-on-insulator. Insertion of a metal ring between the sample stage and glass chamber improves the ion uniformity and reduces the ion fluence non-uniformity as the cathode voltage is raised. Two-dimensional multiple-grid particle-in-cell simulation confirms that the variation of electric field inside the chamber leads to mitigation of the ion focusing phenomenon and the results are corroborated experimentally by hydrogen forward scattering.

  7. A new proton fluence model for E greater than 10 MeV

    NASA Technical Reports Server (NTRS)

    Feynman, Joan; Armstrong, T. P.; Dao-Gibner, L.; Silverman, S.

    1988-01-01

    Researchers describe a new engineering model for the fluence of protons with energies greater than 10 MeV. The data set used is a combination of observations made primarily from the Earth's surface between 1956 and 1963 and observations made from spacecraft in the vicinity of Earth between 1963 and 1985. With this data set we find that the distinction between ordinary proton events and anomalously large proton events made in earlier work disappears. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. In contrast to earlier models, results do not depend critically on the fluence from any one event.

  8. Fluence ablation threshold dependence on tin impurities in commercial soda-lime glass.

    PubMed

    Nieto, Daniel; Arines, Justo; Flores-Arias, María Teresa

    2014-08-20

    In this paper, we study the reduction in the fluence ablation threshold induced by tin impurities incorporated in float soda-lime glass during the fabrication process. The laser system used in the experiments was a Nd:YVO4 laser operating at 1064 nm with a pulse duration of 20 ns. The fluence ablation thresholds found were 112  J/cm2 for the tin side and 920  J/cm2 for the tin-free side, which means a reduction of nearly 1 order of magnitude. The fluence ablation threshold reduction permits the manufacturing of narrower grooves with small level of roughness, obtaining quality elements in low-cost soda-lime substrates. PMID:25321113

  9. Improved ion implant fluence uniformity in hydrogen enhanced glow discharge plasma immersion ion implantation into silicon

    SciTech Connect

    Luo, J.; Li, L. H. E-mail: paul.chu@cityu.edu.hk; Liu, H. T.; Xu, Y.; Zuo, X. J.; Zhu, P. Z.; Ma, Y. F.; Yu, K. M.; Fu, Ricky K. Y.; Chu, Paul K. E-mail: paul.chu@cityu.edu.hk

    2014-06-15

    Enhanced glow discharge plasma immersion ion implantation does not require an external plasma source but ion focusing affects the lateral ion fluence uniformity, thereby hampering its use in high-fluence hydrogen ion implantation for thin film transfer and fabrication of silicon-on-insulator. Insertion of a metal ring between the sample stage and glass chamber improves the ion uniformity and reduces the ion fluence non-uniformity as the cathode voltage is raised. Two-dimensional multiple-grid particle-in-cell simulation confirms that the variation of electric field inside the chamber leads to mitigation of the ion focusing phenomenon and the results are corroborated experimentally by hydrogen forward scattering.

  10. Accelerator-based Neutron Fluence Standard of the National Metrology Institute of Japan

    NASA Astrophysics Data System (ADS)

    Harano, Hideki; Matsumoto, Tetsuro; Nishiyama, Jun; Uritani, Akira; Kudo, Katsuhisa

    2009-03-01

    We report the present status of the national standard on accelerator-based fast neutron fluences in Japan. Monoenergetic neutron fluence standards have been established at 144 keV, 565 keV, 5.0 MeV and 8.0 MeV by using a Van de Graaff accelerator and at 2.5 MeV and 14.8 MeV by using a Cockcroft Walton accelerator. These standards are prepared to measure the detection efficiency and the energy response of neutron sensitive devices, such as personal dosimeters and survey meters. Neutron production and absolute fluence measurement for these energies are described. We are developing a new standard in the energy region of a few tens of keV, which is also introduced here as well as our future plans.

  11. Fluence Evaluations For Applications of In Situ Gamma-Ray Spectrometry in Non-Flat Terrain

    SciTech Connect

    Miller, Kevin M.

    1999-02-28

    Evaluations of gamma-ray fluence are made for source geometries that depart from the flat ground geometry that is used in standard applications of in situ spectrometry. Geometries considered include uniform source distributions for soil mounds on top of flat terrain, cylindrical wells, and rectangular trenches. The results indicate that scaling the standard fluence values for flat terrain by the ratio of solid angle subtended by the soil to 2π leads to fluence estimates that are accurate to within a few percent. Practical applications of in situ spectrometry in non-flat terrain also appears to be simplified by the fact that the angular correction factor for a typical coaxial detector in these geometries may typically be about the same as that computed for flat ground.

  12. Fast Rise Exponential Decay (FRED) Gamma-Ray Bursts and the Fluence Duration Bias

    NASA Astrophysics Data System (ADS)

    Young, K. C.; Hakkila, J.; Giblin, T. W.

    2003-05-01

    The fluences and durations of gamma-ray bursts (GRBs) can be systematically underestimated for low signal-to-noise ratios. This is the result of a human operator selecting a time interval shorter than the burst interval, effectively ignoring burst flux in the fluence calculation. The gradual rise and decay of the FRED-type GRBs are especially susceptible to this bias. Because of the large number of FREDs in the BATSE catalogue, a series of Monte Carlo simulations of hypothetical FREDs have been analyzed. By varying the parameters of the Norris et al. pulse model, the properties of those FREDs most susceptible to the fluence duration bias have been identified. This work is funded by NASA grant NRA-98-OSS-03 and NSF grant AST00-98499.

  13. Coupling effects of the number of pulses, pulse repetition rate and fluence during laser PMMA ablation

    NASA Astrophysics Data System (ADS)

    Liu, Z. Q.; Feng, Y.; Yi, X.-S.

    2000-10-01

    Poly(methyl methacrylate) (PMMA) was ablated using a 248-nm long-pulsed KrF excimer laser operating at a pulse repetition rate (PRR) of 2 and 10 Hz, and fluence varying from 0.4 to 2 J/cm 2. The coupling effects of multiple shots, PRR, and fluence are found and discussed on the etching depth data and topography of PMMA. An increase in either PRR, or fluence or the number of pulses can accelerate the etching efficiency in terms of ablation rate, as a result of strengthened thermal effects. Quality of the craters such as roughness, porosity and contamination is sensitively dependent on the specific laser operating conditions. Basically, increasing the PRR and the number of pulses gives rise to a crater with smoother and less porous bottom.

  14. [18F]DPA-714: Direct Comparison with [11C]PK11195 in a Model of Cerebral Ischemia in Rats

    PubMed Central

    Boutin, Hervé; Prenant, Christian; Maroy, Renaud; Galea, James; Greenhalgh, Andrew D.; Smigova, Alison; Cawthorne, Christopher; Julyan, Peter; Wilkinson, Shane M.; Banister, Samuel D.; Brown, Gavin; Herholz, Karl; Kassiou, Michael; Rothwell, Nancy J.

    2013-01-01

    Purpose Neuroinflammation is involved in several brain disorders and can be monitored through expression of the translocator protein 18 kDa (TSPO) on activated microglia. In recent years, several new PET radioligands for TSPO have been evaluated in disease models. [18F]DPA-714 is a TSPO radiotracer with great promise; however results vary between different experimental models of neuroinflammation. To further examine the potential of [18F]DPA-714, it was compared directly to [11C]PK11195 in experimental cerebral ischaemia in rats. Methods Under anaesthesia, the middle cerebral artery of adult rats was occluded for 60 min using the filament model. Rats were allowed recovery for 5 to 7 days before one hour dynamic PET scans with [11C]PK11195 and/or [18F]DPA-714 under anaesthesia. Results Uptake of [11C]PK11195 vs [18F]DPA-714 in the ischemic lesion was similar (core/contralateral ratio: 2.84±0.67 vs 2.28±0.34 respectively), but severity of the brain ischemia and hence ligand uptake in the lesion appeared to vary greatly between animals scanned with [11C]PK11195 or with [18F]DPA-714. To solve this issue of inter-individual variability, we performed a direct comparison of [11C]PK11195 and [18F]DPA-714 by scanning the same animals sequentially with both tracers within 24 h. In this direct comparison, the core/contralateral ratio (3.35±1.21 vs 4.66±2.50 for [11C]PK11195 vs [18F]DPA-714 respectively) showed a significantly better signal-to-noise ratio (1.6 (1.3–1.9, 95%CI) fold by linear regression) for [18F]DPA-714. Conclusions In a clinically relevant model of neuroinflammation, uptake for both radiotracers appeared to be similar at first, but a high variability was observed in our model. Therefore, to truly compare tracers in such models, we performed scans with both tracers in the same animals. By doing so, our result demonstrated that [18F]DPA-714 displayed a higher signal-to-noise ratio than [11C]PK11195. Our results suggest that, with the longer half-life of

  15. The effect of local fluence on the micropatterning of poly(ethylene terephthalate) foils through proton beam writing

    NASA Astrophysics Data System (ADS)

    de Souza, C. T.; Stori, E. M.; Boufleur, L. A.; Papaléo, R. M.; Dias, J. F.

    2016-07-01

    In this work, we investigate the influence of ion fluence on the development of microstructures produced by 2.2 MeV H+ impinging on 12-μm-thick poly(ethylene terephthalate) (PET, Mylar®) foils. Several lines of 1 × 100 pixels corresponding to approximately 2.5 × 101.5 µm2 were patterned on PET foils using different ion fluences (from 1012 to 1017 H+/cm2) and etching times (from 1 to 60 min). We observe the presence of three different behaviors according to the ion fluence. Long etching times are necessary to open the structure in the low fluence regime, while moderate fluences require shorter etching times. In the high fluence regime, a more complex scenario emerges where short etching times lead to structures either fully or partially developed.

  16. In vivo imaging of microglial activation by positron emission tomography with [(11)C]PBR28 in the 5XFAD model of Alzheimer's disease.

    PubMed

    Mirzaei, Nazanin; Tang, Sac Pham; Ashworth, Sharon; Coello, Christopher; Plisson, Christophe; Passchier, Jan; Selvaraj, Vimal; Tyacke, Robin J; Nutt, David J; Sastre, Magdalena