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1

On the "artificial" nature of Tc and the "carrier-free" nature of 99mTc from 99Mo/99mTc generators.  

PubMed

Two widespread misconceptions regarding Tc are dealt with. First, it is shown that although primordial Tc has decayed completely, Tc is still present in nature due to natural processes, in addition to substantial man-made quantities. Thus, Tc cannot be considered as a purely artificial element. Second, it is shown that (99m)Tc from (99)Mo/(99m)Tc generators is certainly not carrier-free (CF) and that, "no-carrier-added" (NCA) is a more appropriate designation. As a quantitative measure of the amount of long-lived (99g)Tc carrier present in (99m)Tc preparations from generators, the Isotope Dilution Factor (IDF) is used and calculated for some practical situations. PMID:15866445

Alfassi, Zeev B; Groppi, Flavia; Bonardi, Mauro L; de Goeij, Jeroen J M

2005-07-01

2

Results of regular study on radionuclidic purity of 99m Tc obtained from 99 Mo 99m Tc generators  

Microsoft Academic Search

A total of 39 99mTc eluates obtained from 9 99Mo-99mTc generators delivered by The Radiochemical Centre Amersham during one year was studied with regard to their radionuclide purity. Using a Ge(Li) spectrometer the contaminants 60Co, 103Ru, 131I, 134Cs, 140Ba, 140La and 188Re were found in 99mTc-eluates with average levels ranging from 2.9x10-3 to 2.8x10-1 per cent of 99mTc activity. The

Jaroslav Vl?ek; Vįclav Hušįk; Jaroslav Rohį?ek

1979-01-01

3

TC-1 observations of a flux rope: generation by multiple X line reconnection.  

NASA Astrophysics Data System (ADS)

The Flux Transfer Events (FTE) are the manifestation of time-varying reconnection at the Earth magnetopause. The original Russell and Elphic (1978) FTE model predicts a pair of elbow shaped flux ropes of reconnected field lines generated by intermitted and localized reconnection. Alternatively, Lee and Fu (1985) proposes that multiple extended reconnection X lines generate flux ropes at the magnetopause, with the axis roughly aligned to the X lines themselves. On December 29, 2004 the Double Star TC-1 observes several reconnection flow reversals, indicating that the satellite stays close to a reconnection site for about 20 minutes. During the time of observations, TC-1 also detects a flux rope. Because TC-1 observations are made close to the reconnection site, it can be evaluated the direction of the X line as predicted by the component merging model (Sonnerup 1974, Gonzales and Mozer 1974). It is found that the flux rope axis is parallel to such an X line. This fact suggests that the flux rope is probably generated by multiple X lines. The time period under study is characterized by a large and negative Earth dipole tilt and the reconnection line close to TC-1 is found to follow the magnetic equator, passing northward of the subsolar/stagnation point. The interplanetary magnetic field is directed southward and dawnward. Although during the period under study only single point observations are available, the most likely interpretation is that the flux rope is generated when a secondary X line, which has approximately the same orientation of the primary X line near TC-1 and is located south of TC-1 location and passing through the subsolar/stagnation point, is activated.

Trenchi, Lorenzo; Federica Marcucci, Maria; Rčme, Henri; Carr, Christopher M.; Cao, Jinbin

2010-05-01

4

Polymer embedded nanocrystalline titania sorbent for 99Mo-99mTc generator.  

PubMed

A new sorbent material, polymer embedded nano crystalline titania (Titanium Polymer-TiP) has been developed, from titanium (IV) chloride and isopropyl alcohol, for the adsorption of 99Mo, which is a precursor to 99mTc, a workhorse in radio-pharmaceuticals. The infrared absorption spectra of the TiP showed peaks corresponding to Ti-O groups. X-ray diffraction pattern of the adsorbent corresponded to rutile TiO2. The surface area of this polymer was 30 m2/g with an average pore size of 40 nm. The average crystallite size of TiO2, embedded in polymer, was found to be 5 nm. TEM micrograph of the adsorbent revealed the network of polymer with dispersed titania phase. Potential of this adsorbent for the preparation of 99Mo-99mTc generator has been explored. 99Mo could be adsorbed on to the adsorbent column containing TiP at pH 1 from which 99mTC could be eluted with normal (0.9%) saline solution with an elution yield of approximately 80%. The quality of the 99mTcO4 obtained was in accordance with the international specifications applicable for radiopharmaceutical use. A process demonstration run was carried out with 1.1 GBq (30 mCi) 99Mo activity level making use of the above adsorbent and consistent results were obtained over a period of one week, which is generally the shelf life of 99MO-99mTC generator. PMID:19049039

Chakravarty, Rubel; Shukla, Rakesh; Gandhi, Shyamla; Ram, Ramu; Dash, Ashutosh; Venkatesh, Meera; Tyagi, A K

2008-09-01

5

Chemical, radiochemical, and radionuclide purity of eluates from different commercial fission 99 Mo\\/ 99m Tc generators  

Microsoft Academic Search

Seven99Mo\\/99mTc generators (using fission99Mo) obtained from seven different manufactures were studied in 1984 and 1985 to test the quality of the eluates. We present the findings concerning the elution efficiency, radionuclide purity,99Mo breakthrough, radiochemical purity, pH, and aluminium content of the eluates. One generator was overloaded with99Mo by about 40%, while one generator had99mTc yields of only about 80%. The

Andreas Hammermaier; Ernst Reich; Werner Bögl

1986-01-01

6

Ascorbic acid as an eluent for 99m Tc in 99 Mo? 99m Tc generator system  

Microsoft Academic Search

A simple chromatographic procedure for clean separation of the important radionuclide,99m Tc, in the equilibrium mixture,99Mo?99mTc, has been demonstrated. Separation of pure99mTc has been achieved by preferential extraction of the radioisotope through an anion exchange resin column of Amberlite IRA-410\\u000a using Na-ascorbate solution at pH 7 as an eluent. The radiochemical purity of the separated radiotracer has been verified\\u000a by

N. R. Das

1999-01-01

7

Characteristics and behavior of a 99 Mo\\/ 99m Tc generator using irradiated titanium molybdate as column matrix  

Microsoft Academic Search

A99Mo\\/99mTc generator, system was made with a performed titanium molybdate gel. The irradiation was carried out at a medium neutron flux of 1.5×1013 n cm–2·s–1. The irradiated matrix was loaded on top of a column composed of hydrous zirconium oxide alumina. The elution efficiency and the amount of total technetium per mCi99mTc in the generator eluents have been determined. Molybdenum

Y. F. Shafiq; Z. M. Yousif

1995-01-01

8

Preliminary study of quality control of 99 m Tc from 99 Mo generators  

Microsoft Academic Search

The separation of Tc(VII) from Mo(VI) by thin-layer and paper-chromatography is discussed. Some aspects concerning the formation\\u000a and identification of lower oxidation states of Tc(VII) are also mentioned. Finally, a spot test is recommended for the determination\\u000a of Mo(VI) and Al, which can be contaminants in the Tc(VII) solution eluted from the99Mo column, filled with Al2O3.

L. Oniciu; G. B. Cook

1973-01-01

9

Method for generating a crystalline .sup.99 MoO.sub.3 product and the isolation .sup.99m Tc compositions therefrom  

DOEpatents

An improved method for producing .sup.99m Tc compositions. .sup.100 Mo metal is irradiated with photons in a particle (electron) accelerator to produce .sup.99 Mo metal which is dissolved in a solvent. A solvated .sup.99 Mo product is then dried to generate a supply of .sup.99 MoO.sub.3 crystals. The crystals are thereafter heated at a temperature which will sublimate the crystals and form a gaseous mixture containing vaporized .sup.99m TcO.sub.3 and vaporized .sup.99m TcO.sub.2 but will not cause the production of vaporized .sup.99 MoO.sub.3. The mixture is then combined with an oxidizing gas to generate a gaseous stream containing vaporized .sup.99m Tc.sub.2 O.sub.7. Next, the gaseous stream is cooled to a temperature sufficient to convert the vaporized .sup.99m Tc.sub.2 O.sub.7 into a condensed .sup.99m Tc-containing product. The product has high purity levels resulting from the use of reduced temperature conditions and ultrafine crystalline .sup.99 MoO.sub.3 starting materials with segregated .sup.99m Tc compositions therein which avoid the production of vaporized .sup.99 MoO.sub.3 contaminants.

Bennett, Ralph G. (Idaho Falls, ID); Christian, Jerry D. (Idaho Falls, ID); Kirkham, Robert J. (Blackfoot, ID); Tranter, Troy J. (Idaho Falls, ID)

1998-01-01

10

Method for generating a crystalline {sup 99}MoO{sub 3} product and the isolation {sup 99m}Tc compositions therefrom  

DOEpatents

An improved method is described for producing {sup 99m}Tc compositions. {sup 100}Mo metal is irradiated with photons in a particle (electron) accelerator to produce {sup 99}Mo metal which is dissolved in a solvent. A solvated {sup 99}Mo product is then dried to generate a supply of {sup 99}MoO{sub 3} crystals. The crystals are thereafter heated at a temperature which will sublimate the crystals and form a gaseous mixture containing vaporized {sup 99m}TcO{sub 3} and vaporized {sup 99m}TcO{sub 2} but will not cause the production of vaporized {sup 99}MoO{sub 3}. The mixture is then combined with an oxidizing gas to generate a gaseous stream containing vaporized {sup 99m}Tc{sub 2}O{sub 7}. Next, the gaseous stream is cooled to a temperature sufficient to convert the vaporized {sup 99m}Tc{sub 2}O{sub 7} into a condensed {sup 99m}Tc-containing product. The product has high purity levels resulting from the use of reduced temperature conditions and ultrafine crystalline {sup 99}MoO{sub 3} starting materials with segregated {sup 99m}Tc compositions therein which avoid the production of vaporized {sup 99}MoO{sub 3} contaminants. 1 fig.

Bennett, R.G.; Christian, J.D.; Kirkham, R.J.; Tranter, T.J.

1998-09-01

11

Can Based, Decentralised Payload TM/TC Architecture for Next Generation Satcoms  

NASA Astrophysics Data System (ADS)

This paper addresses the optimisation of telecom satellites payload through the use of efficient standard serial buses, together with decentralised and highly integrated units interfacing payload and local telemetry and telecommands. Such an upgraded architecture is under study and assessment through an extensive breadboarding activity including the prototyping of a CAN solution for telecom satellites. Enablers for such upgrade are available building blocks (CAN IP) and building blocks such as mixed ASIC which relevance is shared by numerous actors, allowing access to TM/TC optimised implementation in the near future.

Gunes-Lasnet, S.

2010-08-01

12

Enhanced electricity generation by triclosan and iron anodes in the three-chambered membrane bio-chemical reactor (TC-MBCR).  

PubMed

A three-chambered membrane bio-chemical reactor (TC-MBCR) was developed. The stainless steel membrane modules were used as cathodes and iron plates in the middle chamber served as the anode. The TC-MBCR was able to reduce fouling, remove triclosan (TCS) from a synthetic wastewater treatment and enhance electricity generation by ?60% compared with the cell voltage before TCS addition. The TC-MBCR system generated a relatively stable power output (cell voltage ?0.2V) and the corrosion of iron plates contributed to electricity generation together with microbes on iron anode. The permeation flow from anode to cathode chamber was considered important in electricity generation. In addition, the negatively charged cathode membrane and Fe(2+)/Fe(3+) released by iron plates mitigated membrane fouling by approximately 30%, as compared with the control. The removal of COD and total phosphorus was approximately 99% and 90%. The highest triclosan removal rate reached 97.9%. PMID:24001566

Song, Jing; Liu, Lifen; Yang, Fenglin; Ren, Nanqi; Crittenden, John

2013-07-20

13

Indigenous technology development and standardization of the process for obtaining ready to use sterile sodium pertechnetate-Tc-99m solution from Geltech generator  

PubMed Central

Purpose of the Study: The indigenous design and technology development for processing large scale zirconium molybdate-Mo-99 (ZrMo-99) Geltech generator was successfully commissioned in Board of Radiation and Isotope Technology (BRIT), India, in 2006. The generator production facility comprises of four shielded plant facilities equipped with tongs and special process gadgets amenable for remote operations for radiochemical processing of ZrMo-99 gel. Results: Over 2800 Geltech generators have been processed and supplied to user hospitals during the period 2006-2013. Geltech generator supplied by BRIT was initially not sterile. Simple elution of Tc-99m is performed by a sterile evacuated vial with sterile and pyrogen free 0.9% NaCl solution to obtain sodium (Tc-99m) pertechnetate solution. A special type online 0.22 ?m membrane filter has been identified and adapted in Geltech generator. Conclusions: The online filtration of Tc-99m from Geltech generator; thus, provided sterile Tc-99m sodium pertechnetate solution. Generators assembled with modified filter assembly were supplied to local hospital in Mumbai Radiation Medicine Centre (RMC) and S.G.S. Medical College and KEM Hospital) and excellent performances were reported by users.

Sarkar, Sishir Kumar; Kothalkar, Chetan; Naskar, Prabhakar; Joshi, Sangeeta; Saraswathy, Padmanabhan; Dey, Arun Chandra; Vispute, Gunvant Leeladhar; Murhekar, Vishwas Vinayak; Pilkhwal, Neelam

2013-01-01

14

Separation of 99m Tc from parent 99 Mo by solid-phase column extraction as a simple option for a new 99m Tc generator concept  

Microsoft Academic Search

Evidence is obtained to show that the liquidliquid extraction separation of99mTc from99Mo with methyl ethyl ketone, methyl propyl ketone and methyl isobutyl ketone can be transformed into a solid-phase column extraction procedure. The aqueous alkaline99molybdate solution is immobilized on a column of a granular large-pore diatomaceous earch support, which is the neluted with the abovementioned extractants. Rapid and clean separation

T. Braun; H. Imura; N. Suzuki

1987-01-01

15

Radionuclide Purity of Deliveries of Tc Sodium Pertechnate from the Extraction Generator of the Institute of Nuclear Research, ?ež, Compared with Imported Products  

Microsoft Academic Search

A method is presented of a random control of the radionuclide purity of deliveries of Tc sodium pertechnate pro inj. from the extraction generator of the Institute of Nuclear Research in ?ež. Results are shown of measuring values of activities (in percentage) of the contaminants Mo, I, Co and Re from 1983 to 1986 and after adjusting the technology of

J. Šilar; J. Prokop

1989-01-01

16

Questionnaire survey of hospitals in Saitama Prefecture regarding the shortage of 99m Tc-labeled radiopharmaceuticals and 99 Mo\\/ 99m Tc generators  

Microsoft Academic Search

Objective and methods  A questionnaire survey was conducted at all 32 hospitals in Saitama Prefecture to investigate the current difficult situation\\u000a in terms of nuclear medicine management in the face of the 99mTc shortage due to insufficient supply, and 29 hospitals (90.6%) replied.\\u000a \\u000a \\u000a \\u000a \\u000a Results  Of the 29, 15 (51.7%) reported a reduction in the number of nuclear medicine studies performed due to

Shigeru Kosuda; Hiroko Tomita; Katsumi Hayashi; Tamotsu Kita; Katsumi Koike; Takashi Arai

2010-01-01

17

{sup 99m}Tc generators for clinical use based on zirconium molybdate gel and (n, gamma) produced ā¹ā¹Mo: Indian experience in the development and deployment of indigenous technology and processing facilities  

Microsoft Academic Search

The Indian pursuit of gel generator technology for {sup 99m}Tc was driven mainly by three considerations, namely, (i) well-established and ease of reliable production of (n, gamma)-based ā¹ā¹Mo in several tens of GBq quantities in the research reactors in Trombay\\/Mumbai, India, (ii) need for relatively low-cost alternate technology to replace the solvent (MEK) extraction generator system in use in India

P. Saraswathy; A. C. Dey; S. K. Sarkar; C. Kothalkar; P. Naskar; G. Arjun; S. S. Arora; A. K. Kohli; V. Meera; V. Venugopal; N. Ramamoorthy

2008-01-01

18

Mapping air temperature using time series analysis of LST: the SINTESI approach  

NASA Astrophysics Data System (ADS)

This paper presents a new procedure to map time series of air temperature (Ta) at fine spatial resolution using time series analysis of satellite-derived land surface temperature (LST) observations. The method assumes that air temperature is known at a single (reference) location such as in gridded climate data with grid size of the order of 35 km × 35 km. The LST spatial and temporal pattern within a grid cell has been modelled by the pixel-wise ratios r (x,y,t) of the LST at any location to the LST at a reference location. A preliminary analysis of these patterns over a decade has demonstrated that their intra-annual variability is not negligible, with significant seasonality, even if it is stable throughout the years. The intra-annual variability has been modeled using Fourier series. We have evaluated the intra-annual variability by theoretically calculating the yearly evolution of LST (t) for a range of cases as a function of terrain, land cover and hydrological conditions. These calculations are used to interpret the observed LST (x,y,t) and r (x,y,t). The inter-annual variability has been evaluated by modeling each year of observations using Fourier series and evaluating the interannual variability of Fourier coefficients. Because of the negligible interannual variability of r (x,y,t), LST (x,y,t) can be reconstructed in periods of time different from the ones when LST observations are available. Time series of Ta are generated using the ratio r (x,y,t) and a linear regression between LST and Ta. Such linear regression is applied in two ways: (a) to estimate LST at any time from observations or forecasts of Ta at the reference location; (b) to estimate Ta from LST at any location. The results presented in this paper are based on the analysis of daily MODIS LST observations over the period 2001-2010. The Ta at the reference location was gridded data at a node of a 35 km × 35 km grid. Only one node was close to our study area and was used for the work presented here. The regression of Ta on LST was determined using concurrent observations of Ta at the four available weather stations in the Valle Telesina (Italy), our study area. The accuracy of our estimates is consistent with literature and with the combined accuracy of LST and Ta. We obtained comparable error statistics when applying our method to LST data during periods different but adjacent to the periods used to model of r (x,y,t). The method has also been evaluated against Ta observations for earlier periods of time (1984-1988), although available data are rather sparse in space and time. Slightly larger deviation were obtained. In all cases five days of averages from estimated and observed Ta were compared, giving a better accuracy.

Alfieri, S. M.; De Lorenzi, F.; Menenti, M.

2013-07-01

19

High-(Tc) bolometers.  

National Technical Information Service (NTIS)

A description is given of recent work on high-(Tc) superconducting bolometers for infrared and millimeter wavelengths. The first report describes measurements of the thermal boundary resistance between YBCO films and various substrates. This resistance is...

P. L. Richards J. Clarke Q. Hu R. Leoni P. Lerch

1991-01-01

20

Measurement of neutron activation cross sections for the [sup 99]Tc(n,p) [sup 99]Mo, [sup 99]Tc(n,[alpha]) [sup 96]Nb, [sup 99]Tc (n,n[prime][alpha]) [sup 95]Nb, and [sup 99]Tc(n,n[prime])[sup 99m]Tc reactions at 13. 5 and 14. 8 MeV  

Microsoft Academic Search

The activation cross sections for the [sup 99]Tc(n,p)[sup 99]Mo, [sup 99]Tc(n,[alpha])[sup 96]Nb, [sup 99]Tc(n,n[prime][alpha])[sup 95]Nb, and [sup 99]Tc(n,n[prime])[sup 99n]Tc reactions at 13.5 and 14.8 MeV have been measured by using the deuterium-tritium neutron generator (the Fusion Neutronics Source) at the Japan Atomic Energy Research Institute. The results were compared with experimental values form the literature, evaluated activation cross-section files, and

Y. Ikeda; C. Konno; H. Maekawa; E. T. Cheng

1994-01-01

21

Sustained availability of 99mTc: possible paths forward.  

PubMed

The availability of (99m)Tc for single-photon imaging in diagnostic nuclear medicine is crucial, and current availability is based on the (99)Mo/(99m)Tc generator fabricated from fission-based molybdenum (F (99)Mo) produced using high enriched uranium (HEU) targets. Because of risks related to nuclear material proliferation, the use of HEU targets is being phased out and alternative strategies for production of both (99)Mo and (99m)Tc are being evaluated intensely. There are evidently no plans for replacement of the limited number of reactors that have primarily provided most of the (99)Mo. The uninterrupted, dependable availability of (99m)Tc is a crucial issue. For these reasons, new options being pursued include both reactor- and accelerator-based strategies to sustain the continued availability of (99m)Tc without the use of HEU. In this paper, the scientific and economic issues for transitioning from HEU to non-HEU are also discussed. In addition, the comparative advantages, disadvantages, technical challenges, present status, future prospects, security concerns, economic viability, and regulatory obstacles are reviewed. The international actions in progress toward evolving possible alternative strategies to produce (99)Mo or (99m)Tc are analyzed as well. The breadth of technologies and new strategies under development to provide (99)Mo and (99m)Tc reflects both the broad interest in and the importance of the pivotal role of (99m)Tc in diagnostic nuclear medicine. PMID:23255729

Pillai, Maroor Raghavan Ambikalmajan; Dash, Ashutosh; Knapp, F F Russ

2012-12-19

22

Structure of 94Tc  

Microsoft Academic Search

The level structure and decay properties of levels in 94Tc up to 2307 keV of excitation have been investigated via measurements of excitation functions of singles gamma rays and via ngamma- and gammagamma-coincidence experiments following the 94Mo (p,ngamma) reaction with proton energies between 5.0 and 8.0 MeV. From these experiments and from high resolution singles energy and directional-correlation measurements an

E. Adamides; L. D. Skouras; A. C. Xenoulis

1981-01-01

23

Design and performance of an automated radionuclide separator: Its application on the determination of (99)Tc in groundwater.  

PubMed

A modular automated radionuclide separator for (99)Tc (MARS Tc-99) has been developed for the rapid and reproducible separation of technetium in groundwater samples. The control software of MARS Tc-99 was developed in the LabView programming language. An automated radiochemical method for separating (99)Tc was developed and validated by the purification of (99m)Tc tracer solution eluted from a commercial (99)Mo/(99m)Tc generator. The chemical recovery and analytical time for this radiochemical method were found to be 96±2% and 81min, respectively. PMID:23602584

Chung, Kun Ho; Choi, Sang Do; Choi, Geun Sik; Kang, Mun Ja

2013-03-29

24

INFLUENCE OF NATURAL AND SYNTHETIC ORGANIC LIGANDS ON THE STABILITY AND MOBILITY OF REDUCED TC(IV)  

SciTech Connect

The primary objectives were (1) to quantify the interactions of organic ligands with Tc(IV) through the generation of thermodynamic (complexation) and kinetic parameters needed to assess and predict the mobility of reduced Tc(IV) at DOE contaminated sites; and (2) to determine the impact of organic ligands on the mobility and fate of reduced Tc(IV) under field geochemical conditions.

Nathalie A. Wall; Baohua Gu

2012-12-20

25

Technetium Radiopharmaceuticals:Chemical Characterization and Tissue Distribution of TcGlucoheptonate Using Tc99m and Carrier Tc99  

Microsoft Academic Search

The Chemical structure of the kidney- and brain-imaging agent Tc-99m gluco- heptonate has been established using the Tc-99 isotope. In a comparative study between Tc-99 and Tc-99m glucoheptonates, Chromatographie,electrophoretic, and tissue distributionstudiesshowed identical compoundsin 0.9% NaCI. Optimal conditionsfor the formation of the Tc-99 glucoheptonate complex were investi gated by uv and visible spectroscopy. The oxidation state of Tc-99 in the

Wim de Kieviet

26

Vormgeving hoge-Tc-supergeleiders. (Forming high-Tc superconductors).  

National Technical Information Service (NTIS)

Within the framework of the National Research Program High-Tc Superconductors the Netherlands Energy Research Foundation carried out research on the title subject by means of ceramic techniques. The aim is to manufacture bulk superconductors formed as a w...

L. P. L. Rabou A. Roskam H. C. D. Smit H. J. Veringa

1990-01-01

27

Theory of High-TC Superconductivity: Accurate Predictions of TC  

NASA Astrophysics Data System (ADS)

The superconducting transition temperatures of high-TC compounds based on copper, iron, ruthenium and certain organic molecules is discovered to be dependent on bond lengths, ionic valences, and Coulomb coupling between electronic bands in adjacent, spatially separated layers [1]. Optimal transition temperature, denoted as TC0, is given by the universal expression kBTC0 = e^2?/l?; l is the spacing between interacting charges within the layers, ? is the distance between interacting layers and ? is a universal constant, equal to about twice the reduced electron Compton wavelength (suggesting that Compton scattering plays a role in pairing). Non-optimum compounds in which sample degradation is evident typically exhibit TC < TC0. For the 31+ optimum compounds tested, the theoretical and experimental TC0 agree statistically to within ± 1.4 K. The elemental high-TC building block comprises two adjacent and spatially separated charge layers; the factor e^2/? arises from Coulomb forces between them. The theoretical charge structure representing a room-temperature superconductor is also presented. * 1. doi:10.1088/0953-8984/23/29/295701

Harshman, Dale; Fiory, Anthony

2012-02-01

28

Isotope effect in high- Tc superconductors  

Microsoft Academic Search

For high- Tc superconductors in which transition temperatures Tc are reduced by doping, the oxygen isotope effect (OIE) coefficient in Tc is shown to increase systematically with the pair-breaking rate and with the valence difference between the substituted and native ions. Moreover, the OIE in Tc tends to zero as one approaches optimum (or ideal) stoichiometry at which the quality

Dale R. Harshman; John D. Dow; Anthony T. Fiory

2008-01-01

29

Progress using Tc-99m radiopharmaceuticals for measuring high capacity sites and low density sites.  

PubMed

Technetium-99m (Tc-99m) has long been a mainstay in clinical nuclear medicine, primarily monitoring biological processes in the heart, kidney, liver, and brain. More recently, Tc-99m chelates have been used as the reporter in targeted nuclear medicine probes that monitor changes in specific protein expression products. The strengths remain the inexpensive source of Tc-99m from the Mo-99/Tc-99m generator, its rich chemistry, high-yield kit formulation, and its widespread availability. Hardware and software advances, such as OSEM reconstructions with scatter and attenuation corrections, have led to quantitation of the injected radioactivity in terms of kBq/cm. PMID:23806975

Eckelman, William C; Jones, Alun G; Duatti, Adriano; Reba, Richard C

2013-06-24

30

Technetium99 in generator systems  

Microsoft Academic Search

Technetium-99m solutions always contain Tc-99. The amount varies considerably, depending on production methods and conditions, generator performance, and the time between production or separation and use. There is increasing evidence that labeling and imaging with some radiopharmaceutical kits is adversely affected when the Tc-99 exceeds certain amounts. The sensitivity of particular kits to Tc-99 depends on the ligand, the amount

1984-01-01

31

Effects of FlAsH/Tetracysteine (TC) Tag on PrP Proteolysis and PrPres Formation by TC-Scanning.  

PubMed

Protein-protein interactions associated with proteolytic processing and aggregation are integral to normal and pathological aspects of prion protein (PrP) biology. Characterization of these interactions requires the identification of amino acid residues involved. The FlAsH/tetracysteine (FlAsH/TC) tag is a small fluorescent tag amenable to insertion at internal sites in proteins. In this study, we used serial FlAsH/TC insertions (TC-scanning) as a probe to characterize sites of protein-protein interaction between PrP and other molecules. To explore this application in the context of substrate-protease interactions, we analyzed the effect of FlAsH/TC insertions on proteolysis of cellular prion protein (PrPsen) in in vitro reactions and generation of the C1 metabolic fragment of PrPsen in live neuroblastoma cells. The influence of FlAsH/TC insertion was evaluated by TC-scanning across the cleavage sites of each protease. The results showed that FlAsH/TC inhibited protease cleavage only within limited ranges of the cleavage sites, which varied from about one to six residues in width, depending on the protease, providing an estimate of the PrP residues interacting with each protease. TC-scanning was also used to probe a different type of protein-protein interaction: the conformational conversion of FlAsH-PrPsen to the prion disease-associated isoform, PrPres. PrP constructs with FlAsH/TC insertions at residues 90-96 but not 97-101 were converted to FlAsH-PrPres, identifying a boundary separating loosely versus compactly folded regions of PrPres. Our observations demonstrate that TC-scanning with the FlAsH/TC tag can be a versatile method for probing protein-protein interactions and folding processes. PMID:23943295

Taguchi, Yuzuru; Hohsfield, Lindsay A; Hollister, Jason R; Baron, Gerald S

2013-08-13

32

Power Systems Development Facility Gasification Test Campaign TC25  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

Southern Company Services

2008-12-01

33

Core vibration of 99 Tc  

Microsoft Academic Search

The gyromagnetic ratios and the half-lifes of the 141 keV and 181 keV states of99Tc have been remeasured. The results,g(141 keV)=+1.280(44);g(181 keV)=+1.446(20) andT1\\/2(141 keV)=0.205(4)ns;T1\\/2(181 keV)=3.44(3) ns are in only fair agreement with prior published data but more precise. They confirm that both states are members of the ground state core vibration multiplet. The hyperfine field of TcFe has been determined

I. Alfter; E. Bodenstedt; B. Hamer; W. Knichel; R. Müßeler; R. Sajok; T. Schaefer; J. Schüth; R. Vianden

1993-01-01

34

Human TcR gamma delta+ lymphocyte response on primary exposure to Plasmodium falciparum.  

PubMed Central

In 29 patients experiencing their first P. falciparum malarial attack, blood levels of TcR gamma delta+ lymphocytes were studied from the onset of infection to up to 6-9 months later. Blood TcR gamma delta+ lymphocytes, revealed using the TcR delta 1 monoclonal antibody (MoAb), were increased both in absolute and relative numbers. Alterations lasted for up to 3-4 months following the attack. A Ti gamma A/BB3 reactive V gamma 9 subset was preferentially amplified. In vitro, TcR gamma delta+ lymphocytes from both malaria-sensitized and unprimed donors responded to P. falciparum schizont extract (PFSE). PFSE-stimulated polyclonal T cell lines consisted principally in TcR gamma delta+ cells with a Ti gamma A+/BB3+ phenotype. Several TcR gamma delta+ T cell clones obtained from patients recovering from acute malarial attack were maintained in the presence of PFSE and autologous irradiated PBL. They belong to the V gamma 9 subset. In long-term cultures, TcR gamma delta+ clones progressively lost their capacity to react to PFSE antigen while they were able to proliferate and to exert cytotoxic activity in response to autologous TcR alpha beta+, PFSE-specific T lymphocyte clones. This suggests that regulatory interactions occur between activated TcR gamma delta+ and TcR alpha beta+ cells generated by P. falciparum. Sequential variations in blood TcR gamma delta+ and TcR alpha beta+ lymphocyte levels after primary exposure to P. falciparum suggest that such regulatory interactions may occur in vivo.

Roussilhon, C; Agrapart, M; Guglielmi, P; Bensussan, A; Brasseur, P; Ballet, J J

1994-01-01

35

Technetium-99m generator system  

DOEpatents

A {sup 99}Mo/{sup 99m}Tc generator system includes a sorbent column loaded with a composition containing {sup 99}Mo. The sorbent column has an effluent end in fluid communication with an anion-exchange column for concentrating {sup 99m}Tc eluted from the sorbent column. A method of preparing a concentrated solution of {sup 99m}Tc includes the general steps of: (a) providing a sorbent column loaded with a composition containing {sup 99}Mo, the sorbent column having an effluent end in fluid communication with an anion-exchange column; (b) eluting the sorbent column with a salt solution to elute {sup 99m}Tc from the sorbent and to trap and concentrate the eluted {sup 99m}Tc on the ion-exchange column; and (c) eluting the concentrated {sup 99m}Tc from the ion-exchange column with a solution comprising a reductive complexing agent. 1 fig.

Mirzadeh, S.; Knapp, F.F. Jr.; Collins, E.D.

1998-06-30

36

High Tc Superconductivity --1987  

NASA Astrophysics Data System (ADS)

The discovery of superconductivity in the cuprate class of conducting oxides brought a flash of sunlight on one of the fields condensed matter physics that many of us had thought was rather mature and fairly well understood. Alas, it was not so. In addition to opening a whole new class of materials to the study of correlated motion of charge carriers, it opened a new mind-set that materials with complex chemical bonding can lead to totally new phenomena. The tasks of materials preparation escalated, and with it came the development of totally new spectral probes of the electron gas and the electronic structure in metals. The task is to use complexity so that the interplay of adjacent correlated motion can be used to generate new phenomena that will in turn perform novel functions.

Finnemore, Douglas

2007-03-01

37

Mo-99/Tc-99m Separation: An Assessment of Technical Options  

SciTech Connect

Several strategies for the effective separation of 99mTc from 99Mo have been developed and validated. Due to the success of column chromatographic separation using acidic alumina coupled with high specific activity fission 99Mo (F 99Mo) for production of 99Mo/99mTc generators, however, most technologies until recently have generated little interest. The reduced availability of F 99Mo and consequently the shortage of 99Mo/99mTc column generators in the recent past have resurrected interest in the production of 99Mo as well as 99mTc by alternate routes. Most of these alternative production processes require separation techniques capable of providing clinical grade 99mTc from low specific activity 99Mo or irradiated Mo targets. For this reason there has been renewed interest in alternate separation routes. This paper reviews the reported separation technologies which include column chromatography, solvent extraction, sublimation and gel systems that have been traditionally used for the fabrication of 99Mo/99mTc generator systems. The comparative advantage, disadvantage, and technical challenges toward adapting the emerging requirements are discussed. New developments such as solid-phase column extraction, electrochemical separation, extraction chromatography, supported liquid membrane (SLM) and thermochromatographic techniques are also being evaluated for their potential application in the changed scenario of providing 99mTc from alternate routes. Based on the analysis provided in this review, it appears that some proven separation technologies can be quickly resurrected for the separation of clinical grade 99mTc from macroscopic levels of reactor or cyclotron irradiated molybdenum targets. Furthermore, emerging technologies can be developed further to respond to the expected changing modes of 99mTc production.

Dash, A [Bhabha Atomic Research Centre, Mumbai, India; Pillai, M R A [Bhabha Atomic Research Centre, Mumbai, India; Knapp Jr, Russ F [ORNL

2013-01-01

38

99Mo/(99m)Tc separation: an assessment of technology options.  

PubMed

Several strategies for the effective separation of (99m)Tc from (99)Mo have been developed and validated. Due to the success of column chromatographic separation using acidic alumina coupled with high specific activity fission (99)Mo (F (99)Mo) for production of (99)Mo/(99m)Tc generators, however, most technologies until recently have generated little interest. The reduced availability of F (99)Mo and consequently the shortage of (99)Mo/(99m)Tc column generators in the recent past have resurrected interest in the production of (99)Mo as well as (99m)Tc by alternate routes. Most of these alternative production processes require separation techniques capable of providing clinical grade (99m)Tc from low specific activity (99)Mo or irradiated Mo targets. For this reason there has been renewed interest in alternate separation routes. This paper reviews the reported separation technologies which include column chromatography, solvent extraction, sublimation and gel systems that have been traditionally used for the fabrication of (99)Mo/(99m)Tc generator systems. The comparative advantage, disadvantage, and technical challenges toward adapting the emerging requirements are discussed. New developments such as solid-phase column extraction, electrochemical separation, extraction chromatography, supported liquid membrane (SLM) and thermochromatographic techniques are also being evaluated for their potential application in the changed scenario of providing (99m)Tc from alternate routes. Based on the analysis provided in this review, it appears that some proven separation technologies can be quickly resurrected for the separation of clinical grade (99m)Tc from macroscopic levels of reactor or cyclotron irradiated molybdenum targets. Furthermore, emerging technologies can be developed further to respond to the expected changing modes of (99m)Tc production. PMID:23142410

Dash, Ashutosh; Knapp, F F Russ; Pillai, M R A

2012-11-09

39

Measurement of Tc99 in Savannah River Site High Activity Waste  

Microsoft Academic Search

Waste cleanup efforts currently underway at the Savannah River Site have created a need to characterize Tc-99 in the various high activity waste matrices currently in Site inventories. The traditional method our laboratory used for analyzing Tc-99 in higher activity matrices was a solvent-solvent extraction method using Aliquat-336 in xylene, which resulted in the problematic generation of mixed waste. In

DiPrete

2003-01-01

40

Methyl ethyl ketone extraction of Tc species  

Microsoft Academic Search

Methyl ethyl ketone extraction of technetium species from aqueous solutions of neutron irradiated ammonium molybdate crystals was studied; the two species extracted were separated by high voltage paper electrophoresis. The one was the99mTcO\\u000a4\\u000a–\\u000a ion and the other, a99mTc non-charged immobile species, probably TcO2.aq, which concentrated at the point of application on the electrophoresis paper strip.

S. Bulbulian

1984-01-01

41

Giant electrocaloric effect around Tc.  

PubMed

We use molecular dynamics with a first-principles-based shell model potential to study the electrocaloric effect (ECE) in lithium niobate, LiNbO(3), and find a giant electrocaloric effect along a line passing through the ferroelectric transition. With an applied electric field, a line of maximum ECE passes through the zero field ferroelectric transition, continuing along a Widom line at high temperatures with increasing fields, and along the instability that leads to homogeneous ferroelectric switching below T(c) with an applied field antiparallel to the spontaneous polarization. This line is defined as the minimum in the inverse capacitance under an applied electric field. We investigate the effects of pressure, temperature and an applied electric field on the ECE. The behavior we observe in LiNbO(3) should generally apply to ferroelectrics; we therefore suggest that the operating temperature for refrigeration and energy scavenging applications should be above the ferroelectric transition region to obtain a large electrocaloric response. The relationship between T(c), the Widom line, and homogeneous switching should be universal among ferroelectrics, relaxors, multiferroics, and the same behavior should be found under applied magnetic fields in ferromagnets. PMID:23215332

Rose, Maimon C; Cohen, R E

2012-11-02

42

Giant Electrocaloric Effect Around Tc  

NASA Astrophysics Data System (ADS)

We use molecular dynamics with a first-principles-based shell model potential to study the electrocaloric effect (ECE) in lithium niobate, LiNbO3, and find a giant electrocaloric effect along a line passing through the ferroelectric transition. With an applied electric field, a line of maximum ECE passes through the zero field ferroelectric transition, continuing along a Widom line at high temperatures with increasing fields, and along the instability that leads to homogeneous ferroelectric switching below Tc with an applied field antiparallel to the spontaneous polarization. This line is defined as the minimum in the inverse capacitance under an applied electric field. We investigate the effects of pressure, temperature and an applied electric field on the ECE. The behavior we observe in LiNbO3 should generally apply to ferroelectrics; we therefore suggest that the operating temperature for refrigeration and energy scavenging applications should be above the ferroelectric transition region to obtain a large electrocaloric response. The relationship between Tc, the Widom line, and homogeneous switching should be universal among ferroelectrics, relaxors, multiferroics, and the same behavior should be found under applied magnetic fields in ferromagnets.

Rose, Maimon C.; Cohen, R. E.

2012-11-01

43

Tc-99 Ion Exchange Resin Testing  

SciTech Connect

Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

2010-08-01

44

Oxidative Dissolution Potential of Biogenic and Abiogenic TcO2 in Subsurface Sediments  

SciTech Connect

Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Exhibiting an intermediate redox potential, Tc is highly mobile in its anionic, oxidized state [Tc(VII)O4-]; and less mobile as a poorly soluble oxyhydroxide precipitate [Tc(IV)O2•nH2O] in its reduced state. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state (FRC, RG). Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Biogenic Tc(IV)O2•nH2O was oxidized in anoxic, but unreduced RG and FRC sediments through redox interaction with Mn(III/IV) oxides. Bioreduction by Shewanella putrefaciens CN32 dissolved Mn(III/IV) oxides and generated biogenic Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. Biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO2-like phase in both sediments. Redox product Tc(IV) oxidized rapidly and completely in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular speciation to RG. X-ray microprobe, electron microprobe, x-ray absorption spectroscopy, and micro x-ray diffraction were applied to the whole sediment and isolated Tc-contained particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 µm-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were attributed to mass-transfer-limited migration of O2 into intra-aggregate and intraparticle domains where Tc(IV) existed; and the formation of unique, oxidation-resistant, intragrain Tc(IV)-Fe(III) molecular species.

Fredrickson, Jim K.; Zachara, John M.; Plymale, Andrew E.; Heald, Steve M.; McKinley, James P.; Kennedy, David W.; Liu, Chongxuan; Nachimuthu, Ponnusamy

2009-04-15

45

Grain boundaries in high-Tc superconductors  

Microsoft Academic Search

Since the first days of high-Tc superconductivity, the materials science and the physics of grain boundaries in superconducting compounds have developed into fascinating fields of research. Unique electronic properties, different from those of the grain boundaries in conventional metallic superconductors, have made grain boundaries formed by high-Tc cuprates important tools for basic science. They are moreover a key issue for

H. Hilgenkamp; J. Mannhart

2002-01-01

46

Is technetium-99 (Tc-99) radiologically significant?  

PubMed

According to radiological protection authorities the radioisotope technetium-99 (Tc-99) is not 'radiologically significant' to humans or other species. The Sellafield plutonium reprocessing plant discharges large amounts of Tc-99 into the Irish Sea; by the year 2015 a total of about 3,000 tera-becquerels of Tc-99, weighing about 5 tonnes, will have been discharged. This article considers the effects of Tc-99 on the environment. After discharge, Tc-99 travels large distances in the ocean. Levels of Tc-99 in Norwegian coastal waters increased by ten times between 1991 and 1996. Tc-99 becomes concentrated offshore in seaweed, winkles and mussels. A concentration factor of 120,000 has been reported in seaweed and one of 650,000 has been measured in the green gland of lobster. It may be necessary to reassess the risk to human health following the ingestion of the relevant isotopes, including Tc-99, because of the possibility of radiation induced genomic instability, as well as the cancer risk. The committed effective doses used to determine permitted levels of intake of these isotopes should be increased and the authorized limits for the discharge of radioactive wastes from Sellafield reduced. Authorized limits of the discharge of radioactivity should be based on Contaminated Food Intervention Levels rather than Generalized Derived Limits as they are now. PMID:10218003

Barnaby, F; Boeker, E

47

Scintillating 99Tc Selective Ion Exchange Resins  

SciTech Connect

Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

Mitchell Greenhalgh; Richard D. Tillotson

2012-07-01

48

Technetium generator log form.  

PubMed

Technetium generators are loaded with molybdenum-99 (99Mo), that has a 66-h half life and decays to technetium-99 m (9mTc). 99Tc with a single 140 keV gamma photon emission and a 6-h half life is an ideal isotope for nuclear medicine imaging. Many nuclear medicine units receive generators and use the 99Tc elution to label a variety of prepared chemical species for the majority of the studies they perform. Other options are receiving bulk 99mTc and doing the same tagging or getting unit doses of already labeled pharmaceuticals. Units using generators must meet requirements spelled out in regulations of the Nuclear Regulatory Commission, Title 10, CFR, parts 20, 35, and 71 as well as the Department of Transportation, Title 49, CFR, part 173. The form described in this paper was an attempt to get all of the required records for each individual generator on a single sheet of paper. PMID:11480855

Vernig, P G

2001-08-01

49

Power Systems Development Facility Gasification Test Campaing TC18  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device (PCD), advanced syngas cleanup systems, and high pressure solids handling systems. This report details Test Campaign TC18 of the PSDF gasification process. Test campaign TC18 began on June 23, 2005, and ended on August 22, 2005, with the gasifier train accumulating 1,342 hours of operation using Powder River Basin (PRB) subbituminous coal. Some of the testing conducted included commissioning of a new recycle syngas compressor for gasifier aeration, evaluation of PCD filter elements and failsafes, testing of gas cleanup technologies, and further evaluation of solids handling equipment. At the conclusion of TC18, the PSDF gasification process had been operated for more than 7,750 hours.

Southern Company Services

2005-08-31

50

Investigation into the standardization of 99Tc.  

PubMed

The standardization of (99)Tc by several primary methods was investigated. This was performed to support a new (99)Tc transfer standard that has been developed and will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material SRM 4288B. The standardization for the (99)Tc content of the solution was based on 4pibeta liquid scintillation (LS) measurements with (3)H-standard efficiency tracing (CIEMAT/NIST method). Confirmatory determinations were performed by 4pibeta(LS)-gamma(NaI) live-timed anti-coincidence (LTAC) counting and an LS-based 4pibeta triple-to-double coincidence ratio (TDCR) method. PMID:20060309

Laureano-Perez, L; Collé, R; Fitzgerald, R; Zimmerman, B E; Cumberland, L

2009-12-05

51

Power Systems Development Facility Gasification Test Campaign TC24  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC24, the first test campaign using a bituminous coal as the feedstock in the modified Transport Gasifier configuration. TC24 was conducted from February 16, 2008, through March 19, 2008. The PSDF gasification process operated for about 230 hours in air-blown gasification mode with about 225 tons of Utah bituminous coal feed. Operational challenges in gasifier operation were related to particle agglomeration, a large percentage of oversize coal particles, low overall gasifier solids collection efficiency, and refractory degradation in the gasifier solids collection unit. The carbon conversion and syngas heating values varied widely, with low values obtained during periods of low gasifier operating temperature. Despite the operating difficulties, several periods of steady state operation were achieved, which provided useful data for future testing. TC24 operation afforded the opportunity for testing of various types of technologies, including dry coal feeding with a developmental feeder, the Pressure Decoupled Advanced Coal (PDAC) feeder; evaluating a new hot gas filter element media configuration; and enhancing syngas cleanup with water-gas shift catalysts. During TC24, the PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane.

Southern Company Services

2008-03-30

52

Secrets of soil survival revealed by the genome sequence of Arthrobacter aurescens TC1.  

PubMed

Arthrobacter sp. strains are among the most frequently isolated, indigenous, aerobic bacterial genera found in soils. Member of the genus are metabolically and ecologically diverse and have the ability to survive in environmentally harsh conditions for extended periods of time. The genome of Arthrobacter aurescens strain TC1, which was originally isolated from soil at an atrazine spill site, is composed of a single 4,597,686 basepair (bp) circular chromosome and two circular plasmids, pTC1 and pTC2, which are 408,237 bp and 300,725 bp, respectively. Over 66% of the 4,702 open reading frames (ORFs) present in the TC1 genome could be assigned a putative function, and 13.2% (623 genes) appear to be unique to this bacterium, suggesting niche specialization. The genome of TC1 is most similar to that of Tropheryma, Leifsonia, Streptomyces, and Corynebacterium glutamicum, and analyses suggest that A. aurescens TC1 has expanded its metabolic abilities by relying on the duplication of catabolic genes and by funneling metabolic intermediates generated by plasmid-borne genes to chromosomally encoded pathways. The data presented here suggest that Arthrobacter's environmental prevalence may be due to its ability to survive under stressful conditions induced by starvation, ionizing radiation, oxygen radicals, and toxic chemicals. PMID:17194220

Mongodin, Emmanuel F; Shapir, Nir; Daugherty, Sean C; DeBoy, Robert T; Emerson, Joanne B; Shvartzbeyn, Alla; Radune, Diana; Vamathevan, Jessica; Riggs, Florenta; Grinberg, Viktoria; Khouri, Hoda; Wackett, Lawrence P; Nelson, Karen E; Sadowsky, Michael J

2006-12-01

53

Measurement of Tc-99 in Savannah River Site High Activity Waste  

SciTech Connect

Waste cleanup efforts currently underway at the Savannah River Site have created a need to characterize Tc-99 in the various high activity waste matrices currently in Site inventories. The traditional method our laboratory used for analyzing Tc-99 in higher activity matrices was a solvent-solvent extraction method using Aliquat-336 in xylene, which resulted in the problematic generation of mixed waste. In an effort to eliminate the generation of mixed wastes resulting from the Aliquat 336/xylene process, a variety of different separation methodologies have been studied. Eichrom TEVA solid phase extractions using column technology have been employed in a case by case basis over the last several years. More recently, applications using Eichrom TEVA extraction discs and 3M Empore Tc extraction discs have also been explored.

DiPrete, D.P.

2003-03-27

54

Measurement of Thermal Neutron Cross Section and Resonance Integral of the Reaction Tc(n, ?)Tc  

Microsoft Academic Search

To obtain fundamental data for research on the transmutation of nuclear waste, the thermal neutron cross section and the resonance integral of the reaction Tc(n, ?)Tc have been measured using an activation method.Four ammonium pertechnetate targets containing 371–375 kBq of Tc were irradiated for 2 min with reactor neutrons. Activation detectors of Co\\/Al and Au\\/Al alloy wires were irradiated for

Hideo HARADA; Shoji NAKAMURA; Toshio KATOH; Yoshimune OGATA

1995-01-01

55

Exp 99 Tc Vegetation Reference Material.  

National Technical Information Service (NTIS)

For the past several years participants at the Oak Ridge National Laboratory - Department of Energy Conference on Analytical Chemistry in Energy Technology discussed the need for environmental standards/reference materials for exp 99 Tc. Past efforts at i...

M. S. Feiner

1984-01-01

56

Radioactive Isotopes of Ru and Tc  

Microsoft Academic Search

A new isotope of Ru and one of Tc were found when Mo was bombarded with alpha-particles. The Ru activity decayed with a half-life of 1.65+\\/-0.05 hours. Positrons, x-rays, and gamma-rays were emitted with energies of 1.1 Mev, 0.7A, and 0.95 Mev, respectively. The Ru activity also was produced by fast neutron bombardment of Ru. The Tc activity decayed with

D. T. Eggen; M. L. Pool

1948-01-01

57

BBN TC2000 architecture and progamming models  

SciTech Connect

The BBN TC2000 is a scalable general purpose parallel architecture capable of efficiently supporting both shared memory and message passing programming paradigms. We describe the TC2000 machine architecture and the programming models which we have implemented on it. The parallel programming models are implemented in a portable manner and will be useful on the scalable shared memory machines we expect to see in the future.

Brooks, E.D. III; Gorda, B.C.; Warren, K.H.; Welcome, T.S.

1990-11-01

58

Evaluation of proton induced reactions on 100 Mo: New cross sections for production of 99 m Tc and 99 Mo  

Microsoft Academic Search

The use of the 99Mo99mTc generator in nuclear medicine is well established world wide. The production of the 99Mo (T1\\/2 = 66 h) parent as a fission product of 235U is largely based on the use of reactor technology. From the early 1990's accelerator based production methods to provide either direct produced 99mTc or the parent 99Mo, were studied and

S. Takįcs; Z. Sz?cs; F. Tįrkįnyi; A. Hermanne; M. Sonck

2003-01-01

59

Amyloidosis of heart and liver: comparison of Tc99m pyrophosphate and Tc99m methylene diphosphonate for detection  

Microsoft Academic Search

A prospective, comparative study was made of the efficacy of technetium-99m pyrophosphate (Tc PYP) and technetium-99m methylene diphosphonate (Tc MDP) in detecting soft-tissue amyloidois. Tc PYP and Tc MDP scans were obtained within ten-day intervals in seven patients with histologically proven amyloidosis. Tc PYP was a better scanning agent for soft-tissue amyloidosis in all patients. Cardiac and hepatic involvement were

V. W. Lee; A. G. Caldarone; R. H. Falk; A. Rubinow; A. S. Cohen

1983-01-01

60

Technetium radiopharmaceuticals: chemical characterization and tissue distribution of Tcglucoheptonate using Tc99m and carrier Tc99  

Microsoft Academic Search

The chemical structure of the kidney- and brain-imaging agent Tc-99m glucoheptonate has been established using the Tc-99 isotope. In a comparative study between Tc-99 and Tc-99m glucoheptonathes, chromatographic, electrophoretic, and tissue distribution studies showed identical compounds in 0.9% NaCl. Optimal conditions for the formation of the Tc-99 glucoheptonate complex were investigated by uv and visible spectroscopy. The oxidation state of

de Kieviet

1981-01-01

61

Technetium radiopharmaceuticals: chemical characterization and tissue distribution of Tcglucoheptonate using Tc99m and carrier Tc99  

Microsoft Academic Search

The chemical structure of the kidney- and brain-imaging agent Tc-99m glucoheptonate has been established using the Tc-99 isotope. In a comparative study between Tc-99 and Tc-99m glucoheptonates, chromatographic, electrophoretic, and tissue distribution studies showed identical compounds in 0.9% NaCl. Optimal conditions for the formation of the Tc-99 glucoheptonate complex were investigated by uv and visible spectroscopy. The oxidation state of

de Kieviet

1981-01-01

62

CheckTc and minTc: timing verification and optimal clocking of synchronous digital circuits  

Microsoft Academic Search

Two CAD tools, checkTc and minTc, for timing verification and optimal clocking are introduced. Both tools are based on a new timing model of synchronous digital circuits. The model has the following features: (1) it is general enough to handle arbitrary multiphase clocking; (2) complete, in the sense that it captures signal propagation along short as well as long paths

Karem A. Sakallah; Trevor N. Mudge; Oyekunle A. Olukotun

1990-01-01

63

Pretreatment of TcContaining Waste and Its Effect on Tc99 Leaching From Grouts  

Microsoft Academic Search

A salt solution (doped with Tc-99), that simulates the salt waste stream to be processed at the Saltstone Production Facility, was immobilized in grout waste forms with and without (1) ground granulated blast furnace slag and (2) pretreatment with iron salts. The degree of immobilization of Tc-99 was measured through monolithic and crushed grout leaching tests. Although Fe (+2) was

Albert Aloy; Elena N. Kovarskaya; John R. Harbour; Christine A. Langton; E. William Holtzscheiter

2007-01-01

64

A comparison of rat SPECT images obtained using (99m)Tc derived from 99Mo produced by an electron accelerator with that from a reactor.  

PubMed

Recent shortages of molybdenum-99 ((99)Mo) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce (99)Mo from which technetium-99m ((99m)Tc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced (99m)Tc with those obtained using (99m)Tc from a commercial generator were compared. Disks of (100)Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of (99)Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the (99m)Tc, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using (99m)Tc from a standard reactor (99)Mo generator. The efficiency of (99)Mo-(99m)Tc separation was typically greater than 90%. This study demonstrated the delivery of (99m)Tc from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced (99m)Tc were comparable. High-power electron accelerators are an attractive option for producing (99)Mo on a national scale. PMID:23552053

Galea, R; Wells, R G; Ross, C K; Lockwood, J; Moore, K; Harvey, J T; Isensee, G H

2013-04-03

65

Half Life of {sup 101}Mo and {sup 101}Tc {beta}{sup -}-decay  

SciTech Connect

In this work, the half-lives of the beta-unstable nuclei {sup 101}Mo and {sup 101}Tc were studied using neutron-irradiated samples of {sup 100}Mo to produce {sup 101}Mo which in its turn generates {sup 101}Tc by beta decay. The gamma activity of each sample was followed for 5 consecutive half-lives in steps of 5 minutes. A total of 22 sources were measured and checked for dead-time influence, and the half-lives were obtained by weighted average. The results are statistically incompatible with the tabulated values.

Silva, Antonio Carlos O. da; Genezini, Frederico A.; Zamboni, Cibele B.; Zahn, Guilherme S. [Centro do Reator de Pesquisas (CRPq)-Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP). Av. Linneu Prestes, 2242-Cidade Universitaria, Sao Paulo, SP, 05507-000 (Brazil); Cruz, Manoel Tiago F. da [Instituto da Fisica da Universidade de Sao Paulo (IFUSP), Sao Paulo, SP (Brazil)

2009-06-03

66

Uptake, biotransformation, and elimination of 99Tc in duckweed.  

PubMed

Aquatic plants may play an important role in the environmental fate of the long-lived radioactive waste product 99Tc. Aquatic plants show a strong accumulation and retention of Tc, even after they have died. This study focuses on possible bio-organic Tc compounds formed in the water dwelling plant duckweed to possibly explain the accumulation and retention. Moreover, a change in chemical speciation often implies a different fate and behaviour in the biosphere. A mild separation technique was used to distinguish between reduced Tc species and TcO(4)(-). Accumulation experiments suggested that reduction of Tc(VII)O(4)(-) and subsequent complexation are responsible for the accumulation of Tc in duckweed. A steady state concentration of TcO(4)(-) in duckweed was reached within 24 h, but the total concentration of Tc increased continuously. Only a small part (Tc was present as TcO(4)(-). Elimination experiments showed that TcO(4)(-) is the only mobile species. Other Tc species are responsible for the retention of Tc in duckweed. It is known that these species are not bio-available and only slowly re-oxidise to pertechnetate, resulting in a longer residence time in ecosystems. PMID:12873399

Hattink, Jasper; Harms, Arend V; de Goeij, Jeroen J M

2003-08-01

67

Comparison of Tc-99m pyrophosphate and Tc-99m hydroxymethylene diphosphonate in acute myocardial infarction: concise communication  

SciTech Connect

A clinical comparison between a new bone seeking radiopharmaceutical, Tc-99m hydroxymethylene diphosphonate (TcHMDP) and the standard agent, Tc-99m pyrophosphate (TcPPi), was performed in 18 patients with acute myocardial infarction. Each patient was imaged initially with either TcHMDP or TcPPi, and imaged 24 h later with the other tracer. All 18 patients had images positive for acute myocardial infarction with TcPPi, whereas 16 or 18 patients (89%) had positive studies with TcHMDP. The TcPPi images were graded significantly superior to those obtained with TcHMDP in 61% of the patients, and they were equal in 33%. In only one patient (6%) was TcHMDP better. The results indicate that compared with TcHMDP, TcPPi not only has a superior sensitivity for acute myocardial infarction but also has a significantly increased intensity of uptake in positive areas. TcPPi remains the agent of choice for myocardial infarct imaging.

Wakat, M.A.; Chilton, H.M.; Hackshaw, B.T.; Cowan, R.J.; Ball, J.D.; Watson, N.E. Jr.

1980-03-01

68

t-Model mechanism of high-{Tc} cuprates  

SciTech Connect

A doublon formalism of d-p model Hubbard Hamiltonian is studied only with transfer integrals, and without the superexchange term. This gives excellent doping-dependent features of {Tc} in high-{Tc} cuprates.

Murayama, Yoshimasa [Advanced Research Lab., Saitama (Japan); Nakajima, Sadao [Tokai Univ., Kanagawa (Japan)

1994-12-01

69

Women, Family Systems & the TC. Chapter 8.  

ERIC Educational Resources Information Center

|This document contains 11 papers from the ninth World Conference of Therapeutic Communities (TCs) that deal with women's issues, family systems, and the TC. Papers include: (1) "Families in the Eighties" (Cecil Williams); (2) "Women, Work & Substance Abuse" (Lois Morris); (3) "The National Federation of Parents" (Shirley Colletti); (4) "The…

Acampora, Alfonso P., Ed.; Nebelkopf, Ethan, Ed.

70

Neutron Resonance Parameters for Tc-99 (Technetium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Tc-99 (Technetium). Also included are Maxwellian-averaged cross sections at temperatures kT.

Sukhoruchkin, S. I.; Soroko, Z. N.

71

Tc enhancement in superconductor-semiconductor arrays  

Microsoft Academic Search

The enhancement of the superconducting transition temperature Tc is investigated in terms of changing the phonon spectrum and also by studying size quantization. Attention is given to the observation by Kwok and Fung (1991) that Tl- and Bi-based superconductors comprise arrays of superconductors and semiconductors. Kresin's (1982) theoretical arguments are used to examine whether the weak-coupling BCS model can be

W. Y. Kwok; P. C. W. Fung; C. C. Lam

1991-01-01

72

STME T\\/C casting technology  

Microsoft Academic Search

The T\\/C casting technology developed by the National Launch System for the Space Transportation Main Engine is described. Special attention is given to the selection of JBK-75 as the combustion chamber casting alloy, some unique casting issues, and the development castings which were produced. Current plans call for producing a 650K full cast jacket mockup in the 4500 pound furnace.

J. R. Lobitz; P. C. Ackerman; S. L. Weber

1992-01-01

73

IRGA for MIMO systems based on TC  

Microsoft Academic Search

The control of MIMO systems plays an important part in industrial process, and the coupling in MIMO systems is a key issue of control. This paper introduces an input relative gain array(IRGA) to the design of Tornambe's Controller(TC) to find a proper match between the inputs and outputs. The results of simulation show that this method can find appropriate match

Yunfan Zhang; Donghai Li; Dazhong Lao

2011-01-01

74

High-Tc Superconducting Thin Film Devices.  

National Technical Information Service (NTIS)

In this dissertation, a number of approaches were explored for the fabrication of high-Tc superconducting ultra-thin films and multilayer thin films by using pulsed laser deposition and reactive molecular beam epitaxy with an ozone source. With these film...

Z. W. Dong

1995-01-01

75

Power Systems Development Facility Gasification Test Campaign TC22  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC22, the first test campaign using a high moisture lignite from Mississippi as the feedstock in the modified Transport Gasifier configuration. TC22 was conducted from March 24 to April 17, 2007. The gasification process was operated for 543 hours, increasing the total gasification operation at the PSDF to over 10,000 hours. The PSDF gasification process was operated in air-blown mode with a total of about 1,080 tons of coal. Coal feeder operation was challenging due to the high as-received moisture content of the lignite, but adjustments to the feeder operating parameters reduced the frequency of coal feeder trips. Gasifier operation was stable, and carbon conversions as high as 98.9 percent were demonstrated. Operation of the PCD and other support equipment such as the recycle gas compressor and ash removal systems operated reliably.

Southern Company Services

2008-11-01

76

Power Systems Development Facility Gasification Test Campaign TC16  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR (formerly Kellogg Brown & Root) Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report discusses Test Campaign TC16 of the PSDF gasification process. TC16 began on July 14, 2004, lasting until August 24, 2004, for a total of 835 hours of gasification operation. The test campaign consisted of operation using Powder River Basin (PRB) subbituminous coal and high sodium lignite from the North Dakota Freedom mine. The highest gasifier operating temperature mostly varied from 1,760 to 1,850 F with PRB and 1,500 to 1,600 F with lignite. Typically, during PRB operations, the gasifier exit pressure was maintained between 215 and 225 psig using air as the gasification oxidant and between 145 and 190 psig while using oxygen as the oxidant. With lignite, the gasifier operated only in air-blown mode, and the gasifier outlet pressure ranged from 150 to 160 psig.

Southern Company Services

2004-08-24

77

Tc-99m PYP localization in calf muscle necrosis  

SciTech Connect

Tc-99m pyrophosphate (PYP) can localize in an acute myocardial infarct and other extraosseous lesions, including soft tissue necrosis and severe cellular injury A case of Tc-99m PYP uptake in calf muscle necrosis following transfemoral cardiac catheterization is presented. This was incidentally detected on Tc-99m PYP imaging performed for an acute myocardial infarction. Repeat Tc-99m PYP imaging one month later was normal, implying resolution of the ischemic muscle necrosis.

Virupannavar, S.; Shirazi, P.H.; Khedkar, N.V.; Kaplan, E.

1984-05-01

78

Torelenes (t)Cn as a New Class of Carbon Clusters. Electronic Structure of (t)-C200, (t)-C210, (t)-C276, and (t)-C408  

Microsoft Academic Search

Structures of four giant torus-like carbon clusters are proposed: (t)-C200 (I), (t)-C210 (II), (t)-C408 (III) and (t)-C276 (IY). Their electronic structures are calculated by a topological approach. It is discovered that electronic shell of cluster (II) containing (4n+2) ?-electrons with n = 52 is closed. Its spectrum gap is equal to 0.4. (In units of resonance integral ? module.) Clusters

E. G. Galpern; I. V. Stankevich; A. L. Chistyakov; L. A. Chernozatonskii

1994-01-01

79

A scheme of Maglev vehicle using high Tc bulk superconducters  

Microsoft Academic Search

High Tc superconductors are highly attractive because they can operate at liquid nitrogen temperature. The high performance of high Tc bulk superconductors is exciting to people in the application research work on superconducting magnetic levitation (Maglev) vehicle. The Maglev concept using high Tc bulk superconductors has been demonstrated by the Beijing Small Model. In this paper, schemes relating to the

Wang Jiasu; Wang Suyu; Ren Zhongyou; Dong Xiaogang; Lin Guobin; Lian Jisan; Zhang Cuifang; Huang Haiyu; Deng Changyan; Zhu Dequi

1999-01-01

80

TC Research: State of the Art. Chapter 3.  

ERIC Educational Resources Information Center

|This document contains six papers from the ninth World Conference of Therapeutic Communities that highlight research on therapeutic communities (TC) and discuss how to apply research findings in practical ways. Papers include: (1) "TC Research: Overview & Implications" (George De Leon); (2) "Emerging Cross-Cultural TC Research" (D. Vincent Biase…

Acampora, Alfonso P., Ed.; Nebelkopf, Ethan, Ed.

81

Effect of increased 99m Tc\\/ 99 Tc ratios on count rates in sentinel node procedures: a randomised study  

Microsoft Academic Search

The aim of this study was to evaluate the count rates of sentinel lymph nodes (SLNs) in patients with breast cancer in the operating theatre, using 99mTc-Nanocoll with different ratios of technetium-99m to technetium-99. After written informed consent had been obtained, we tested different ratios of 99mTc\\/ 99Tc-Nanocoll in a double-blinded randomised study performed in 161 patients. Twenty-five MBq\\/µg 99mTc-colloid

G. M. M. Gommans; F. M. van der Zant; T. G. van der Schors; A. van Dongen; G. J. J. Teule; W. W. J. Clarijs; B. L. A. M. Langenhorst; J. W. D. de Waard

2003-01-01

82

Myocardial uptake of Tc-99m-tetrofosmin and Tc-99m-MIBI  

SciTech Connect

Tc-99m-tetrofosmin is an alternative for Tc-99m-MIBI as myocardial perfusion tracer, with easier kit preparation and less liver activity. Dual isotope simultaneous acquisition (DISA) SPECT using Tc-99m-MIBI and 18-FDG is a promising technique for the assessment of myocardial viability. Disturbing scatter from 511 keV photons in the 140 keV channel can be minimized with an activity ratio 18-FDG to Tc-99m-MIBI for DISA, the relative myocardial uptake of both tracers was investigated in neonatal rat myocytes (in medium with 0.2% BSA at 37{degrees}C during 60 min, measurements in triplicate) and in 6 patients at rest, who underwent myocardial perfusion scintigraphy for the evaluation of coronary artery disease. Rest SPECT (high resolution parallel collimators, 360{degrees}, 3{degrees} per step of 30 sec) was performed at least 1 hr after the injection of 370 MBq Tc-99m-tetrofosmin. Rest SPECT with 370 MBq Tc-99m-MIBI was repeated 1 week later. Counts in a fixed circular ROI around the heart in the raw projection images from 40{degrees} RAO to 90{degrees} left lateral were compared for tetrofosmin and MIBI, while images with overlying intestinal or liver activity were omitted. In the rat myocytes the cell associated activity of Tc-99m- MIBI was 0.9 {plus_minus} 0.02% D/10 {mu}g protein after 5 min, 4.73 {plus_minus} 0.09% at 10 min, and 8.76 {plus_minus} 0.19% at 60 min. The cell activity of Tc-99m-tetrofosmin was 0.36 {plus_minus} 0.04% at 10 min, 1.96 {plus_minus} 0.22% at 30 min, and 3.89 {plus_minus} 0.47% at 60 min. The MIBI/tetrofosmin ratio was 2.3 {plus_minus} 0.1. In 3 patients all 41 projection images could be evaluated, in 2 patients 36 images, and in 1 patient only 22. The average counts per ROI ranges from 8577 to 16341 for MIBI and from 8088 to 15375 for tetrofosmin. The individual MIBI/tetrofosmin ratios ranges from 0.97 {plus_minus} 0.03 to 1.31 {plus_minus} 0.04. In vitro, the retention of Tc-99m-MIBI is twice that of Tc-99m-tetrofosmin.

Valkema, R.; Jong, M. de; Reijs, A. [University Hospital Dijkzigt, Rotterdam (Netherlands)] [and others

1996-05-01

83

99mTc-MIBI, 99mTc-Tetrofosmin and 99mTc-Q12 In Vitro and In Vivo  

Microsoft Academic Search

The aim of this study was to compare uptake of 99mTc-MIBI, 99mTc-tetrofosmin and 99mTc-Q12 in vitro and biodistribution in vivo in rats. In vitro, uptake decreased in the order MIBI?tetrofosmin?Q12. Uptake of MIBI and tetrofosmin, but not of Q12, in cultured tumor cells was dependent on the plasma membrane and mitochondrial potential. In vivo, heart uptake of all three compounds

Bert F Bernard; Eric P Krenning; Wout A. P Breeman; Geert Ensing; Harry Benjamins; Willem H Bakker; Theo J Visser; Marion de Jong

1998-01-01

84

Comparison of Tc99m MDP, Tc99m HSA and Tc99m HIG uptake in rheumatoid arthritis and its variants  

Microsoft Academic Search

Tc-99m polyclonal immunoglobulin-G has been shown to be a successful agent in the depiction of active inflammation in rheumatoid\\u000a arthritis (RA). The objective of this study was to compare the uptake behaviors of Tc-99m HIG and Tc-99m MDP in RA and variants\\u000a of rheumatoid arthritis (VRA). Seventeen patients with RA and 8 patients with VRA presenting with active inflammation were

Murathan Sahin; Irem Bernay; Tarik Basoglu; Ferhan Canturk

1999-01-01

85

Impairments in motor coordination without major changes in cerebellar plasticity in the Tc1 mouse model of Down syndrome  

PubMed Central

Down syndrome (DS) is a genetic disorder arising from the presence of a third copy of human chromosome 21 (Hsa21). Recently, O'Doherty et al. [An aneuploid mouse strain carrying human chromosome 21 with Down syndrome phenotypes. Science 309 (2005) 2033–2037] generated a trans-species aneuploid mouse line (Tc1) that carries an almost complete Hsa21. The Tc1 mouse is the most complete animal model for DS currently available. Tc1 mice show many features that relate to human DS, including alterations in memory, synaptic plasticity, cerebellar neuronal number, heart development and mandible size. Because motor deficits are one of the most frequently occurring features of DS, we have undertaken a detailed analysis of motor behaviour in cerebellum-dependent learning tasks that require high motor coordination and balance. In addition, basic electrophysiological properties of cerebellar circuitry and synaptic plasticity have been investigated. Our results reveal that, compared with controls, Tc1 mice exhibit a higher spontaneous locomotor activity, a reduced ability to habituate to their environments, a different gait and major deficits on several measures of motor coordination and balance in the rota rod and static rod tests. Moreover, cerebellar long-term depression is essentially normal in Tc1 mice, with only a slight difference in time course. Our observations provide further evidence that support the validity of the Tc1 mouse as a model for DS, which will help us to provide insights into the causal factors responsible for motor deficits observed in persons with DS.

Galante, Micaela; Jani, Harsha; Vanes, Lesley; Daniel, Herve; Fisher, Elizabeth M.C.; Tybulewicz, Victor L.J.; Bliss, Timothy V.P.; Morice, Elise

2009-01-01

86

Method for the production of .sup.99m Tc compositions from .sup.99 Mo-containing materials  

DOEpatents

An improved method for producing .sup.99m Tc compositions from .sup.99 Mo compounds. .sup.100 Mo metal or .sup.100 MoO.sub.3 is irradiated with photons in a particle (electron) accelerator to ultimately produce .sup.99 MoO.sub.3. This composition is then heated in a reaction chamber to form a pool of molten .sup.99 MoO.sub.3 with an optimum depth of 0.5-5 mm. A gaseous mixture thereafter evolves from the molten .sup.99 MoO.sub.3 which contains vaporized .sup.99 MoO.sub.3, vaporized .sup.99m TcO.sub.3, and vaporized .sup.99m TcO.sub.2. This mixture is then combined with an oxidizing gas (O.sub.2(g)) to generate a gaseous stream containing vaporized .sup.99m Tc.sub.2 O.sub.7 and vaporized .sup.99 MoO.sub.3. Next, the gaseous stream is cooled in a primary condensation stage in the reaction chamber to remove vaporized .sup.99 MoO.sub.3. Cooling is undertaken at a specially-controlled rate to achieve maximum separation efficiency. The gaseous stream is then cooled in a sequential secondary condensation stage to convert vaporized .sup.99m Tc.sub.2 O.sub.7 into a condensed .sup.99m Tc-containing reaction product which is collected.

Bennett, Ralph G. (Idaho Falls, ID); Christian, Jerry D. (Idaho Falls, ID); Grover, S. Blaine (Idaho Falls, ID); Petti, David A. (Idaho Falls, ID); Terry, William K. (Idaho Falls, ID); Yoon, Woo Y. (Idaho Falls, ID)

1998-01-01

87

Method for the production of {sup 99m}Tc compositions from {sup 99}Mo-containing materials  

DOEpatents

An improved method is described for producing {sup 99m}Tc compositions from {sup 99}Mo compounds. {sup 100}Mo metal or {sup 100}MoO{sub 3} is irradiated with photons in a particle (electron) accelerator to ultimately produce {sup 99}MoO{sub 3}. This composition is then heated in a reaction chamber to form a pool of molten {sup 99}MoO{sub 3} with an optimum depth of 0.5--5 mm. A gaseous mixture thereafter evolves from the molten {sup 99}MoO{sub 3} which contains vaporized {sup 99}MoO{sub 3}, vaporized {sup 99m}TcO{sub 3}, and vaporized {sup 99m}TcO{sub 2}. This mixture is then combined with an oxidizing gas (O{sub 2(g)}) to generate a gaseous stream containing vaporized {sup 99m}Tc{sub 2}O{sub 7} and vaporized {sup 99}MoO{sub 3}. Next, the gaseous stream is cooled in a primary condensation stage in the reaction chamber to remove vaporized {sup 99}MoO{sub 3}. Cooling is undertaken at a specially-controlled rate to achieve maximum separation efficiency. The gaseous stream is then cooled in a sequential secondary condensation stage to convert vaporized {sup 99m}Tc{sub 2}O{sub 7} into a condensed {sup 99m}Tc-containing reaction product which is collected. 1 fig.

Bennett, R.G.; Christian, J.D.; Grover, S.B.; Petti, D.A.; Terry, W.K.; Yoon, W.Y.

1998-09-01

88

Laser surface interactions of high- Tc superconductors  

SciTech Connect

During the past two years, one of the most exciting research fields in science has been the study of the newly discovered high-{Tc} metal oxide superconductors. Although many theoretical models were proposed, there has been no general agreement on any theory to explain these materials. One of the peculiar'' features of these high-{Tc} materials is the noninteger number of oxygen atoms. The oxygen content is extremely critical to the superconductive properties. Our results from mass spectroscopy of laser desorbed species indicate that significant quantities of oxygen molecules are trapped in the bulk of these superconductors. It appears that these trapped oxygen molecules may play key roles in superconductive properties. 23 refs., 4 figs., 1 tab.

Chen, C.H.; McCann, M.P.; Phillips, R.C.

1990-01-01

89

Shock compaction of high- Tc superconductors  

SciTech Connect

We present the results of shock compaction experiments on high-{Tc} superconductors and describe the way in which shock consolidation addresses critical problems concerning the fabrication of high J{sub c} bulk superconductors. In particular, shock compaction experiments on YBa{sub 2}Cu{sub 3}O{sub 7} show that shock-induced defects can greatly increase intragranular critical current densities. The fabrication of crystallographically aligned Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} samples by shock-compaction is also described. These experiments demonstrate the potential of the shock consolidation method as a means for fabricating bulk high-{Tc} superconductors having high critical current densities.

Weir, S.T.; Nellis, W.J.; McCandless, P.C.; Brocious, W.F. (Lawrence Livermore National Lab., CA (USA)); Seaman, C.L.; Early, E.A.; Maple, M.B. (California Univ., San Diego, La Jolla, CA (USA). Dept. of Physics); Kramer, M.J. (Ames Lab., IA (USA)); Syono, Y.; Kikuchi, M. (Tohoku Univ., Sendai (Japan))

1990-09-01

90

High-temperature superconductors above Tc  

NASA Astrophysics Data System (ADS)

An outline is given of a model of high-temperature superconductors developed by the author, following Prelovsek et al. and others. Attention is given particularly to the behaviour of these materials above Tc. Phenomena not dealt with previously are the highly anistropic compound Bi2.1Sr1.9CuO6+/-? (Fiori et al.), which gives strong support for the model, and recent results of the Cambridge group on doping YBCO with Zn or Co.

Mott, Nevill

1990-09-01

91

High TC superconductors—composite wire fabrication  

Microsoft Academic Search

Commercially useful, bulk superconductors typically require stabilization using a normal metal cladding for reasons of electrical, thermal, and mechanical protection and, in general, need to be drawn into fine fibers and wound into a magnet configuration. The recent discovery of high-TC superconductor materials such as Ba2YCu3O7 stimulated worldwide interest in the subject, however, with much concern about fabricability of such

S. Jin; R. C. Sherwood; R. B. van Dover; T. H. Tiefel; D. W. Johnson

1987-01-01

92

Studies on chemical effects on x-ray intensity ratios of K beta \\/K alpha in nuclear decay of technetium nuclides 99mTc, 97mTc, and 95mTc  

Microsoft Academic Search

Chemical effects of characteristic x-ray intensity ratios of K?\\/K? were investigated for the second d-group element Tc in the decay processes 99mTc ? 99Tc (two-step isomeric transition), 97mTc ? 97Tc (one-step isomeric transition), and 95mTc ? 95Mo (electron capture). The objective nuclides were produced by (n, ?)??, (d, xn), and (?, xn) reactions and were chemically separated from the target

I. Yamoto; H. Kaji; K. Yoshihara

1986-01-01

93

PRETREATMENT OF TC CONTAINING WASTE AND ITS EFFECT ON 99 TC LEACHING FROM GROUTS  

SciTech Connect

A salt solution (doped with Tc-99), that simulates the salt waste stream to be processed at the Saltstone Production Facility, was immobilized in grout waste forms with and without (1) ground granulated blast furnace slag and (2) pretreatment with iron salts. The degree of immobilization of Tc-99 was measured through monolithic and crushed grout leaching tests. Although Fe (+2) was shown to be effective in reducing Tc-99 to the +4 state, the strong reducing nature of the blast furnace slag present in the grout formulation dominated the reduction of Tc-99 in the cured grouts. An effective diffusion coefficient of 4.75 x 10{sup -12} (Leach Index of 11.4) was measured using the ANSI/ANS-16.1 protocol. The leaching results show that, even in the presence of a concentrated salt solution, blast furnace slag can effectively reduce pertechnetate to the immobile +4 oxidation state. The measured diffusivity was introduced into a flow and transport model (PORFLOW) to calculate the release of Tc-99 from a Saltstone Vault as a function of hydraulic conductivity of the matrix.

Harbour, J

2006-12-11

94

Biogeochemical Coupling of Fe and Tc Speciation in Subsurface Sediments: Implications to Long-Term Tc Immobilization  

SciTech Connect

The project has been focused on biochemical processes in subsurface sediments involving Fe that control the valence state, solubility, and effective mobility of 99Tc. Our goal has been to understand the Tc biogeochemistry as it may occur in suboxic and biostimulated subsurface environments. Two objectives have been pursued: (1) To determine the relative reaction rates of 99Tc(VII)O2(aq) with metal reducing bacteria and biogenic Fe(II); and to characterize the identity, structure, and molecular speciation of Tc(IV) products formed through reaction with both biotic and abiotic reductants. (2) To quantify the biogeochemical factors controlling the reaction rate of O2 with Tc(IV)O2?nH2O in sediment resulting from the direct enzymatic reduction of Tc(VII) by DIRB and/or the reaction of Tc(VII) with the various types of biogenic Fe(II) produced by DIRB.

Jim K. Fredrickson; C. I. Steefel; R. K. Kukkadapu; S. M. Heald

2006-06-01

95

Half-lives and Q ? measurements for new nuclei of89Tc and89mTc  

NASA Astrophysics Data System (ADS)

Neutron deficient isotopes of89Tc and89mTc have been produced through the60Ni(32S, p 2 n)89Tc at 95 MeV and the58Ni(35Cl, 2 p 2 n)89Tc reaction at 135 MeV. A rotating catcher foil system was used to collect the activities and transfer them to a measuring position for ?-? spectroscopy. The half-lives of89Tc and89mTc were measured to be 12.8±0.9 s and 12.9±0.8 s, respectively. The total decay energy, QEC, for89Tc was determined to be 7.51±0.21 MeV.

Heiguchi, K.; Hosoda, T.; Komatsubara, T.; Nomura, T.; Furuno, K.; Nakatani, R.; Mitarai, S.; Kuroyanagi, T.

1991-03-01

96

The new 99mTc myocardial perfusion imaging agents: 99mTc-sestamibi and 99mTc-teboroxime  

SciTech Connect

The two new 99m (99mTc) labeled myocardial perfusion agents, 99mTc-Sestamibi and 99mTc-Teboroxime, are now available for routine clinical application. Both agents allow assessment of ejection fraction by the first-pass technique at rest or during exercise, thus providing additional information not available with thallium-201. 99mTc-Sestamibi has long myocardial residence time, as well as adequate myocardial extraction, providing images of higher count density and superior quality compared with thallium-201. 99mTc-Teboroxime has excellent myocardial uptake characteristics but is cleared very rapidly from the myocardium. Both tracers have shown results similar to those obtained with thallium-201 for detection of coronary artery disease and the assessment of defect reversibility. 99mTc-Sestamibi studies using the rest/stress imaging sequence can be accomplished in approximately 5 hours; studies using dual-isotope imaging (rest thallium-201 and stress 99mTc-Sestamibi injection) can be completed in 1 to 2 hours. Gated stress images can be performed with 99mTc-Sestamibi, providing simultaneous information of myocardial perfusion at stress and resting wall motion or thickening and allowing rapid differentiation of ischemic from infarcted tissue. Because of its slow myocardial clearance and absence of redistribution, 99mTc-Sestamibi allows uncoupling of the time of injection from the time of imaging and thus can be valuable in the evaluation of acute myocardial infarction and outcome of thrombolytic therapy. With 99mTc-Teboroxime, rapid serial studies are feasible. Pharmacologic stress and rest studies with 99mTc-Teboroxime single photon emission computed tomography potentially can be completed in under 30 minutes. 73 references.

Berman, D.S.; Kiat, H.; Maddahi, J. (Department of Medicine (Division of Cardiology), Cedars-Sinai Medical Center, Los Angeles, CA (United States))

1991-09-01

97

Voltage-biased high-Tc superconducting infrared bolometers with strong electrothermal feedback  

Microsoft Academic Search

In the current generation of high-Tc bolometers the thermal conductance is often chosen for a short time-constant rather than for optimal sensitivity. We describe a novel bolometer bias and readout scheme that promises to relax this constraint. Voltage bias of the superconductor results in strong negative electrothermal feedback that greatly reduces the time-constant of the bolometer. We estimate that a

Adrian T. Lee; Jan M. Gildemeister; Shih-Fu Lee; Paul L. Richards

1997-01-01

98

A comparison of the tumor-seeking agent Tc-99m(V) dimercaptosuccinic acid and the renal imaging agent Tc-99m dimercaptosuccinic acid in humans.  

PubMed

Being aware of the ideal nuclear properties of Tc-99m, our interest has been focused on the design of the (+5) oxidation state Tc-99m(V) dimercaptosuccinic acid (Tc(V)-DMSA) as a tumor-seeking agent. Tc-99m(V) DMSA holds a TcO4(3-) core and, like PO4(3-), has excellent characteristics for tumor uptake, but has a different distribution than the well-known renal scanning agent, Tc-99m DMSA. The differences in chemical behavior of Tc-99m(V) DMSA and Tc-99m DMSA are discussed. Three cases in which neoplasms were studies with Tc-99m(V) DMSA and Tc-99m DMSA are presented. Tc-99m DMSA and Tc-99m(V) DMSA, having a common ligand and tracer but, with the metal ion core in a different oxidation state, the uptake characteristics are altered markedly. PMID:2985320

Ohta, H; Ishii, M; Yoshizumi, M; Endo, K; Sakahara, H; Nakajima, T; Yomoda, I; Masuda, H; Horiuchi, K; Hata, N

1985-03-01

99

Pentavalent Tc-99m dimercaptosuccinic acid imaging of hepatocellular carcinoma.  

PubMed

Tc-99m (V)-dimercaptosuccinic acid (DMSA) has been used to image various kinds of tumors. However, from a review of the literature, it has never been applied to hepatocellular carcinoma (HCC). Low uptake of Tc-99m (V)-DMSA has been demonstrated in normal liver tissue, thus, Tc-99m (V)-DMSA may be useful for the detection of HCC. Nine male patients with focal nodular HCC were studied with sequential X-ray CT, Tc-99m (V)-DMSA and Tc-99m phytate liver scan. Our data showed that eight patients had increased uptake of Tc-99m (V) DMSA in HCC. Four cases demonstrated higher Tc-99m (V) DMSA uptake in HCC than in adjacent liver, and four cases demonstrated HCC uptake equal to liver uptake. One case showed no uptake of Tc-99m (V) DMSA in HCC. The detection sensitivity of Tc-99m (V)-DMSA was 88.9%. From our early results, Tc-99m (V)-DMSA is a readily available tumor imaging agent that appears to accumulate in HCC. PMID:10613606

Wang, S J; Lin, W Y; Wey, S P; Shen, L H; Ting, G

1999-01-01

100

Shape coexistence and isomeric states in neutron-rich {sup 112}Tc and {sup 113}Tc  

SciTech Connect

Isomeric states in {sup 112}Tc and {sup 113}Tc, with half-lives of 150(17) ns and 500(100) ns, respectively, have been observed following the relativistic fission of {sup 238}U. The fission fragments have been separated in a fragment separator and identified by means of energy-loss and time-of-flight techniques. In both nuclei, the ground-state configuration is calculated to have an oblate shape and the isomerism is proposed to arise due to transitions from a triaxial excited state to a low-lying oblate state.

Bruce, A. M.; Lalkovski, S.; Denis Bacelar, A. M. [School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4GJ (United Kingdom); Gorska, M.; Bednarczyk, P.; Caceres, L.; Geissel, H.; Gerl, J.; Kojouharov, I.; Kurz, N.; Prokopowicz, W.; Schaffner, H.; Tashenov, S.; Wollersheim, H. J. [Gesellschaft fuer Schwerionenforschung mbH, Planckstrasse 1, D-64291 Darmstadt (Germany); Pietri, S. [Gesellschaft fuer Schwerionenforschung mbH, Planckstrasse 1, D-64291 Darmstadt (Germany); Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Podolyak, Zs.; Walker, P. M.; Cullen, I. J.; Farrelly, G. F.; Garnsworthy, A. B. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

2010-10-15

101

Development of more efficacious Tc-99m organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures. Progress report, May 1, 1981-April 30, 1982  

SciTech Connect

The objectives of this year's research were to develop a method for rapidly determining TcO/sub 4//sup -/ in /sup 99/Mo//sup 99m/Tc generator eluates, to improve the ability to chromatographically determine individual Tc-HEDP complexes in radiopharmaceuticals, and to investigate the effects of TcO/sub 4//sup -/ concentration and electrochemical reduction on the types and relative amounts of Tc-HEDP complexes present in a radiopharmaceutical formulation. A rapid and sensitive high performance liquid chromatographic (HPLC) method for the quantitative determination of pertechnetate (TcO/sub 4//sup -/) was developed. This HPLC-based analysis may be of considerable utility in assessing the history and function of /sup 99/MO/sup 99m/Tc generators as well as in the routine analysis of reduced technetium radiopharmaceuticals for the presence of undesired TcO/sub 4//sup -/. Encouraging results were obtained on a dimethyl amine column using aqueous (NH/sub 4/)/sub 2/SO/sub 4/ as the mobile phase. The preparation of Tc(NaBH/sub 4/) HEDP radiopharmaceutical analogues using varying concentrations of total TcO/sub 4//sup -/ shows a dramatic effect in the number and distribution of Tc-HEDP complexes over a TcO/sub 4//sup -/ concentration range of 10/sup -2/ to 10/sup -8/M. These results suggest that total TcO/sub 4//sup -/ concentration is an important parameter to be considered in the preparation of a specific Tc-HEDP complex to improve skeletal imaging. The preparation of Tc(electrode) HEDP radiopharmaceutical analogues by using electrochemical reduction was explored. The resulting solutions contain Tc-HEDP complexes that are tentatively identified as being the same complexes formed by NaBH/sub 4/ reduction, although the relative concentrations of these complexes are quite different with the two modes of reduction. Thus, electrochemical reduction shows promise as a viable route to the preparation of specific Tc-HEDP complexes for improved skeletal imaging.

Heineman, W.R.; Deutsch, E.A.

1981-12-01

102

Common Physical Properties of DNA Affecting Target Site Selection of Sleeping Beauty and other Tc1\\/ mariner Transposable Elements  

Microsoft Academic Search

Sleeping Beauty (SB) is the most active Tc1\\/mariner-type transposable element in vertebrates, and is therefore a valuable vector for transposon mutagenesis in vertebrate models and for human gene therapy. We have analyzed factors affecting target site selection of SB in mammalian cells, by generating transposition events from extrachromosomal plasmids to chromosomes. In contrast to the local hopping observed when transposition

Thomas J. Vigdal; Christopher D. Kaufman; Zsuzsanna Izsvįk; Daniel F. Voytas; Zoltįn Ivics

2002-01-01

103

NMR investigation of low energy excitations in high Tc superconductors  

NASA Astrophysics Data System (ADS)

We review the NMR results in the normal state (T > Tc) of superconducting YBa2Cu3O6+x single crystals as a function of oxygen hole doping. We show that the characteristic energy ? = ???'/?'' for low-energy excitations can be deduced both from NMR (for antiferromagnetic QAF and zero wave vector), and from inelastic neutron scattering for QAF only. In underdoped (dTc/dx > 0) samples ?(0) is found to be constant down to Tc, while ?(QAF) starts to increase below ~ 150 K, i.e., well above Tc, reflecting the opening of the pseudogap for magnetic excitations at QAF. In overdoped samples (dTc/dx < 0) there is only the superconducting gap opening at Tc, supporting the phase diagram based on the spin-charge separation.

Berthier, C.; Gillet, J. A.; Auler, T.; Berthier, Y.; Horvati?, M.; Ségransan, P.; Henry, J. Y.

1993-01-01

104

An update on the direct production of {sup 99m}Tc with proton beams and enriched {sup 100}Mo targets  

SciTech Connect

Technetium-99m (6.02 h) radiopharmaceuticals are used extensively throughout the world for diagnosing a variety of diseases using nuclear medicine techniques. It is supplied conveniently and reliably by elution of {sup 99m}Tc radioactivities from a {sup 99}Mo, {sup 99m}Tc generator, a device fully dependent on the production of the parent {sup 99}Mo (66.02 h) using reactor methods. As an alternative to reactor methods and to the use of {sup 99}Mo {r_arrow} {sup 99m}Tc generators, we have proposed an accelerator-based method to produce {sup 99m}Tc directly. This method, investigated since 1990, is based on the use of accelerated proton beams and enriched targets via the {sup 100}Mo(p,2n){sup 99m}Tc reaction (Q = -7.9 MeV). Instant {sup 99m}Tc produced in this fashion would have to be produced in regional/centralized accelerator facilities limiting the supply to local/regional users. In comparison to existing reactor and generator techniques, this method would have several economical advantages as it would minimize nuclear waste production and management costs as well as public and environmental health concerns associated with nuclear reactors.

Lagunas-Solar, M.C.; Zeng, N.X.; Mirshad, I. [Univ. of California, Davis, CA (United States); Grey-Morgan, T. [Amersham International plc, Amersham Laboratories, Buckinghamshire (United Kingdom)

1996-12-31

105

Systematic evaluation of 99mTc-tetrofosmin versus 99mTc-sestamibi to study murine myocardial perfusion in small animal SPECT/CT  

PubMed Central

Background The “back-translation” of clinically available protocols to measure myocardial perfusion to preclinical imaging in mouse models of human disease is attractive for basic biomedical research. With respect to single-photon emission computed tomography (SPECT) approaches, clinical myocardial perfusion imaging protocols are established with different 99mTc-labeled perfusion tracers; however, studies evaluating and optimizing protocols for these tracers in high-resolution pinhole SPECT in mice are lacking. This study aims at evaluating two clinically available 99mTc-labeled myocardial perfusion tracers (99mTc-sestamibi vs. 99mTc-Tetrofosmin) in mice using four different imaging protocols. Methods Adult C57BL/6 male mice were injected with 99mTc-sestamibi (MIBI) or 99mTc-Tetrofosmin (TETRO) (4 MBq/g body weight) either intravenously through the tail vein (n?=?5) or retroorbitally (n?=?5) or intraperitoneally (i.p.) under anesthesia (n?=?3) or i.p. in an awake state (n?=?3) at rest. Immediately after injection, a multi-frame single-photon emission computed tomography/computed tomography (SPECT/CT) acquisition was initiated with six subsequent time frames of 10 min each. Reconstructed images of the different protocols were assessed and compared by visual analysis by experts and by time-activity-curves generated from regions-of-interest for various organs (normalized uptake values). Results Visually assessing overall image quality, the best image quality was found for MIBI for both intravenous injection protocols, whereas TETRO only had comparable image quality after retroorbital injections. These results were confirmed by quantitative analysis where left ventricular (LV) uptake of MIBI after tail vein injections was found significantly higher for all time points accompanied with a significantly slower washout of 16% for MIBI vs. 33% for TETRO (p?=?0.009) from 10 to 60 min post injection (PI). Interestingly, LV washout from 10 to 60 min PI was significantly higher for TETRO when applied by tail vein injections when compared to retroorbital injections (22%, p?=?0.008). However, liver uptake was significant and comparable for both tracers at all time points. Radioactivity concentration in the lungs was negligible for all time points and both tracers. Conclusion Intravenous MIBI injection (both tail vein and retroorbital) results in the best image quality for assessing myocardial perfusion of the murine heart by SPECT/CT. TETRO has a comparable image quality only for the retroorbital injection route.

2012-01-01

106

Uptake kinetics of 99Tc in common duckweed  

Microsoft Academic Search

The uptake of the nuclear waste product technetium-99 was studied in common duckweed (Lemna minor). In addition to measurements, a model involving two compartments in duckweed with different chemical forms of technetium was derived. The model was tested by chemical speciation, i.e. differentiating between reduced Tc-compounds and TcVIIO4?. The TcO4? concentrations measured were in good agreement with those predicted by

Jasper Hattink; Jeroen J. M. de Goeij; Hubert Th. Wolterbeek

2000-01-01

107

A giant nucleopore protein that binds Ran\\/TC4  

Microsoft Academic Search

RAN\\/TC4 is a small nuclear G protein1 that forms a complex with the chromatin-bound guanine nucleotide release factor RCC1 (ref. 2). Loss of RCC1 causes defects in cell cycle progression3,4, RNA export5-7 and nuclear protein import8. Some of these can be suppressed by overexpression of Ran\\/TC4 (ref. 1), suggesting that Ran\\/TC4 functions downstream of RCC1. We have searched for proteins

N. Yokoyama; N. Hayashi; T. Seki; N. Panté; T. Ohba; K. Nishii; K. Kuma; T. Hayashida; T. Miyata; U. Aebi; M. Fukui; T. Nishimoto

1995-01-01

108

STME T/C casting technology  

NASA Astrophysics Data System (ADS)

The T/C casting technology developed by the National Launch System for the Space Transportation Main Engine is described. Special attention is given to the selection of JBK-75 as the combustion chamber casting alloy, some unique casting issues, and the development castings which were produced. Current plans call for producing a 650K full cast jacket mockup in the 4500 pound furnace. Once a 650K mockup casting has been successfully produced, a design of experiments (DOE) will be conducted to establish the best gating system. This will be followed by the design of permanent wax pattern tooling, gating tooling, and process fixtures, and, finally, by a process DOE.

Lobitz, J. R.; Ackerman, P. C.; Weber, S. L.

1992-07-01

109

The unusually frail asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

The first asteroid to be discovered in space and subsequently observed to impact Earth, asteroid 2008 TC3, exploded at a high 37 km altitude and stopped ablating at 32 km. This would classify the fireball as of Ceplecha's PE-criterion IIIb/a, meaning “cometary” in nature. In this case, the structural weakness may have come from pores found in some of the recovered meteorites, called “Almahata Sitta” (= Station 6 in Arabic). The explosion turned most of the asteroid mass to dust and vapor, only a tiny fraction shattered into macroscopic meteorites, the heaviest of which was 283 gram. Other similarly frail asteroids may be related to main belt comets.

Jenniskens, Peter; Shaddad, Muawia H.; Shaddad

110

Rethinking the properties of the quark-gluon plasma at Tc Tc  

Microsoft Academic Search

We argue that although at asymptotically high temperatures the quark-gluon plasma (QGP) in bulk behaves as a gas of weakly interacting quasiparticles (modulo long-range magnetism), it is different at temperatures up to few times the critical temperature Tc . In particular, we emphasize the role of several zero binding lines on the phase diagrams, below which cÆ c , light

Edward V. Shuryak; Ismail Zahed

2004-01-01

111

Behavior of reduced 99\\/Tc and 99\\/Tc organic complexes on Hanford soil  

Microsoft Academic Search

Both synthetically and naturally derived organic complexing agents in soil have been found in other studies to accelerate the rate of migration of specific radionuclides. In an effort to aid in the development of comprehensive plans for the disposal of low-level waste, the effect of organic complexing agents on the transport properties of Tc, a long-lived constituent of radioactive waste,

J. A. Franz; L. Y. Martin; D. J. Wiggins

1982-01-01

112

Superconducting fluctuations and disorder in high-Tc cuprates  

NASA Astrophysics Data System (ADS)

The determination of critical fields and of the superconducting fluctuations in the cuprates are still highly debated questions, as both extremely high field and reduced Tc cuprates are required to attempt to reach the normal state regime. We have studied in fields up to 60T the variation of the transverse magnetoresistance (MR) of underdoped YBCO6.6 crystals either pure or with Tc reduced down to 3.5K by electron irradiation [1]. We show that the normal state MR is restored above a threshold field Hc^'(T), which is found to vanish at Tc^'>>Tc. This allows us to evidence a (H,T) range where superconductivity survives at least as fluctuations. When Tc is decreased by disorder, we found that the fluctuation range expands significantly as Tc^' is slightly depressed. This Tc^' behaves similarly versus defect content as the onset temperature T? of the Nernst signals measured on the same samples [2] which indicates that the Tc decrease is partly due to the loss of the phase coherence. We found that Tc^', Hc^'(T) and T? which can be related to pair formation are depressed, although moderately, by the introduction of defects in contrast to the pseudogap temperature which is known to be insensitive to disorder, showing that these energy scales are not related. [1] F. Rullier-Albenque et al, cond-mat 0610838 [2] F. Rullier-Albenque et al., Phys. Rev. Lett. 96, 067002 (2006)

Rullier-Albenque, Florence; Alloul, Henri; Proust, Cyril

2007-03-01

113

Assessment of renal function in mice with unilateral ureteral obstruction using 99mTc-MAG3 dynamic scintigraphy  

PubMed Central

Background Renal scintigraphy using 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) is widely used for the assessment of renal function in humans. However, the application of this method to animal models of renal disease is currently limited, especially in rodents. Here, we have applied 99mTc-MAG3 renal scintigraphy to a mouse model of unilateral ureteral obstruction (UUO) and evaluated its utility in studying obstructive renal disease. Methods UUO mice were generated by complete ligation of the left ureter. Sham-operated mice were used as a control. Renal function was investigated on days 0, 1, 3, and 6 post-surgery using dynamic planar imaging of 99mTc-MAG3 activity following retro-orbital injection. Time-activity curves (TACs) were produced for individual kidneys and renal function was assessed by 1) the slope of initial 99mTc-MAG3 uptake (SIU), which is related to renal perfusion; 2) peak activity; and 3) the time-to-peak (TTP). The parameters of tubular excretion were not evaluated in this study as 99mTc-MAG3 is not excreted from UUO kidneys. Results Compared to sham-operated mice, SIU was remarkably (>60%) reduced in UUO kidneys at day 1 post surgery and the TACs plateaued, indicating that 99mTc-MAG3 is not excreted in these kidneys. The plateau activity in UUO kidneys was relatively low (~40% of sham kidney’s peak activity) as early as day1 post surgery, demonstrating that uptake of 99mTc-MAG3 is rapidly reduced in UUO kidneys. The time to plateau in UUO kidneys exceeded 200 sec, suggesting that 99mTc-MAG3 is slowly up-taken in these kidneys. These changes advanced as the disease progressed. SIU, peak activity and TTPs were minimally changed in contra-lateral kidneys during the study period. Conclusions Our data demonstrate that renal uptake of 99mTc-MAG3 is remarkably and rapidly reduced in UUO kidneys, while the changes are minimal in contra-lateral kidneys. The parametric analysis of TACs suggested that renal perfusion as well as tubular uptake is reduced in UUO kidneys. This imaging technique should allow non-invasive assessments of UUO renal injury and enable a more rapid interrogation of novel therapeutic agents and protocols.

2012-01-01

114

Concentration and clearance of Tc-99m-pyridoxylidene isoleucine by a hepatoma.  

PubMed

Usually hepatic tumors show focal defects on both Tc-99m-colloid liver and Tc-99m-hepatobiliary imaging. This report involves a rare case in which a hepatoma did not take up Tc-99m-phytate, but concentrated and cleared a Tc-99m-hepatobiliary agent, Tc-99m-pyridoxylidene isoleucine. PMID:6245828

Ueno, K; Haseda, Y

1980-05-01

115

Characterization of 99m Tc\\/ 99 Tc-hydroxycarboxylic acid chelates by high voltage electrophoresis without supporting material  

Microsoft Academic Search

Ion mobilities of different99mTc- and99Tc chelates prepared by reduction of pertechnetate by Sn(II) in the presence of citric, malic, tartaric, gluconic, and ?-hydroxyisobutyric\\u000a acid as ligands have been measured by means of electrophoresis without supporting material. All the chelates investigated\\u000a proved to be anions in the pH range of 2–7. Both the Tc(V)- and Tc(IV) compounds with the same ligand

I. Hoffmann; R. Muenze; I. Dreyer; R. Dreyer

1982-01-01

116

Uptake kinetics of 99Tc in common duckweed.  

PubMed

The uptake of the nuclear waste product technetium-99 was studied in common duckweed (Lemna minor). In addition to measurements, a model involving two compartments in duckweed with different chemical forms of technetium was derived. The model was tested by chemical speciation, i.e. differentiating between reduced Tc-compounds and Tc(VII)O(4)(-). The TcO(4)(-) concentrations measured were in good agreement with those predicted by the model. Two processes determine technetium uptake: (1) transport of Tc(VII)O(4)(-) across the cell membrane, and (2) reduction of Tc(VII). The TcO(4)(-) concentration in duckweed reaches a steady state within 2 h while reduced Tc-compounds are stored, as a result of absence of release or re-oxidation processes. Bioaccumulation kinetic properties were derived by varying 99Tc concentration, temperature, nutrient concentrations, and light intensity. The reduction of technetium in duckweed was highly correlated with light intensity and temperature. At 25 degrees C the maximum reduction rate was observed at light intensities above 200 µmol m(-2) s(-1) while half of the maximum transformation rate was reached at 41 µmol m(-2) s(-1). Transport of TcO(4)(-) over the cell membrane requires about 9.4 kJ mol(-1), indicating an active transport mechanism. However, this mechanism behaved as first-order kinetics instead of Michaelis-Menten kinetics between 1x10(-14) and 2.5x10(-5) mol l(-1) TcO(4)(-). Tc uptake could not be inhibited by 10(-3) mol l(-1) nitrate, phosphate, sulphate or chloride. PMID:10927124

Hattink; de Goeij JJ; Wolterbeek

2000-08-01

117

Voltage-biased high-{Tc} superconducting infrared bolometers with strong electrothermal feedback  

SciTech Connect

In the current generation of high-{Tc} bolometers the thermal conductance is often chosen for a short time-constant rather than for optimal sensitivity. We describe a novel bolometer bias and readout scheme that promises to relax this constraint. Voltage bias of the superconductor results in strong negative electrothermal feedback that greatly reduces the time-constant of the bolometer. We estimate that a decrease of more than one order of magnitude in time-constant should be possible with existing high-Tc thermometers. We give theoretical estimates of the performance gain with voltage bias for several bolometers that have been reported in the literature. We find cases where the sensitivity can be greatly improved (by changing the thermal conductance) while holding the time constant fixed and others where the bolometer can be made much faster while maintaining the sensitivity.

Lee, A.T. [California Univ., Berkeley, CA (United States). Center for Particle Astrophysics; Gildemeister, J.M. [California Univ., Berkeley, CA (United States). Dept. of Physics; Lee, Shih-Fu; Richards, P.L. [Lawrence Berkeley National Lab., CA (United States)

1996-08-01

118

Photoreduction of {sup 99}Tc Pertechnetate by Nanometer-Sized Metal Oxides: New Strategies for Formation and Sequestration of Low-Valent Technetium  

SciTech Connect

Technetium-99 ({sup 99}Tc) ({beta}{sup -}{sub max}: 293.7 keV; t{sub 1/2}: 2.1 x 10{sup 5} years) is a byproduct of uranium-235 fission and comprises a large component of radioactive waste. Under aerobic conditions and in a neutral- basic environment, the pertechnetate anion (TcO{sub 4}{sup -}) is stable. TcO{sub 4}{sup -} is very soluble, migrates easily through the environment and does not sorb well onto mineral surfaces, soils or sediments. This study moves forward a new strategy for the reduction of TcO4- and chemical incorporation of the reduced Tc into a metal oxide material. This strategy employs a single material, a polyoxometalate (POM), {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-}, that can be photoactivated in the presence of 2-propanol to transfer electrons to TcO{sub 4}{sup -}, and incorporate the reduced Tc covalently into the {alpha}2- framework to form the Tc{sup V}O species, Tc{sup V}O({alpha}{sub 2}-P{sub 2}W{sub 17}O{sub 61}){sup 7-}. This occurs via the formation of an intermediate species that slowly converts to Tc{sup V}O({alpha}{sub 2}-P{sub 2}W{sub 17}O{sub 61}){sup 7-}. EXAFS and XANES analysis and preliminary EPR analysis, suggests that the intermediate consists of a Tc(IV) {alpha}2- species where the Tc is likely bound to only 2 of the 4 W-O oxygen atoms in the {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} defect. This intermediate then oxidizes and converts to the Tc{sup V}O({alpha}{sub 2}-P{sub 2}W{sub 17}O{sub 61}){sup 7-} product. The reduction and incorporation of TcO{sub 4}{sup -} was accomplished in a "one pot" reaction using both sunlight and UV irradiation, and monitored as a function of time using multinuclear NMR and radio TLC. The process was further probed by the "step-wise" generation of reduced {alpha}{sub 2}-P{sub 2}W{sub 17}O{sub 61}{sup 12-} through bulk electrolysis followed by the addition of TcO{sub 4}{sup -}. The reduction and incorporation of ReO{sub 4}{sup -}, as a non-radioactive surrogate for {sup 99}Tc, does not proceed through the intermediate species, and Re{sup V}O is incorporated quickly into the {alpha}{sub 2}-[P{sub 2}W{sub 17}O{sub 61}]{sup 10-} defect. These observations are consistent with the periodic trends of Tc and Re. Specifically, Tc is more easily reduced compared to Re. In addition to serving as models for metal oxides, POMs may also provide a suitable platform to study the molecular level dynamics and mechanisms of the reduction and incorporation of Tc into a material.

Burton-Pye, Benjamin P.; Radivojevic, Ivana; McGregor, Donna; Mbomekalle, Israel M.; Lukens, Jr., Wayne W.; Francesconi, Lynn C.

2011-07-04

119

IRES-driven Expression of the Capsid Protein of the Venezuelan Equine Encephalitis Virus TC-83 Vaccine Strain Increases Its Attenuation and Safety  

PubMed Central

The live-attenuated TC-83 strain is the only licensed veterinary vaccine available to protect equids against Venezuelan equine encephalitis virus (VEEV) and to protect humans indirectly by preventing equine amplification. However, TC-83 is reactogenic due to its reliance on only two attenuating point mutations and has infected mosquitoes following equine vaccination. To increase its stability and safety, a recombinant TC-83 was previously engineered by placing the expression of the viral structural proteins under the control of the Internal Ribosome Entry Site (IRES) of encephalomyocarditis virus (EMCV), which drives translation inefficiently in insect cells. However, this vaccine candidate was poorly immunogenic. Here we describe a second generation of the recombinant TC-83 in which the subgenomic promoter is maintained and only the capsid protein gene is translated from the IRES. This VEEV/IRES/C vaccine candidate did not infect mosquitoes, was stable in its attenuation phenotype after serial murine passages, and was more attenuated in newborn mice but still as protective as TC-83 against VEEV challenge. Thus, by using the IRES to modulate TC-83 capsid protein expression, we generated a vaccine candidate that combines efficient immunogenicity and efficacy with lower virulence and a reduced potential for spread in nature.

Guerbois, Mathilde; Volkova, Eugenia; Forrester, Naomi L.; Rossi, Shannan L.; Frolov, Ilya; Weaver, Scott C.

2013-01-01

120

Muscle localization of Tc-99m MDP after exertion  

SciTech Connect

Very high muscle uptake of Tc-99m MDP was seen two days after the start of a program of vigorous weight-lifting exercises. Localization of Tc-99m bone tracer in muscle that has been damaged by exertion may be a more common phenomenon than is recognized at present.

Valk, P.

1984-09-01

121

Induced transparency in EXAFS as cuprate superconductors go through Tc  

Microsoft Academic Search

The increased transmission, observed in the EXAFS region of their X-ray absorption spectra, as cuprate materials go through the superconducting transition temperature Tc is correlated with an increase in Abrikosov Vortex expulsion in zero magnetic field as the temperature T approaches Tc.

J. G. Chigvinadze; G. I. Mamniashvilli; J. V. Acrivos

2005-01-01

122

Pedal Tc-99m phytate lymphoscintigraphy in primary chylopericardium.  

PubMed

This paper describes a case of 65-year-old woman with primary chylopericardium. She received Tc-99m phytate lymphoscintigraphy after pericardial drainage and was managed with medium-chain triglycerides without surgical intervention. This was the first reported case of primary chylopericardium diagnosed with Tc-99m phytate lymphoscintigraphy. PMID:12957775

Chen, Fu-Chung; Huang, Jin-Long; Lin, Wan-Yu; Ting, Chih-Tai

2003-08-01

123

Iron oxide waste form for stabilizing 99Tc  

NASA Astrophysics Data System (ADS)

Crystals of goethite were synthesized with reduced technetium [99Tc(IV)] incorporated within the solid lattice. The presence of 99Tc(IV) as a substituting cation in the matrix and "armoring" by an additional layer of precipitated goethite isolated the reduced 99Tc(IV) from oxidizing agents. These products were used to make monolithic pellets to quantify an effective diffusion coefficient for 99Tc from goethite waste form contacted with a synthetic Hanford IDF (Integrated Disposal Facility) pore water solution (pH = 7.2 and I = 0.05 M) at room temperature for up to 120 days in static reactors. XANES analysis of the goethite solids recovered post-run demonstrated that the 99Tc in the goethite crystals remains in the reduced 99Tc(IV) state. The slow release of pertechnetate concentration with time in the static experiments with the monolith followed a square root of time dependence, consistent with diffusion control for 99Tc release. An apparent diffusion coefficient of 6.15 × 10-11 cm2/s was calculated for the 99Tc-goethite pellet sample and the corresponding leaching index (LI) was 10.2. The results of this study indicate that technetium can be immobilized in a stable, low-cost Fe oxide matrix that is easy to fabricate and these findings can be useful in designing long-term solutions for nuclear waste disposal.

Um, Wooyong; Chang, Hyunshik; Icenhower, Jonathan P.; Lukens, Wayne W.; Jeffrey Serne, R.; Qafoku, Nik; Kukkadapu, Ravi K.; Westsik, Joseph H.

2012-10-01

124

Iron Oxide Waste Form for Stabilizing 99Tc  

SciTech Connect

Crystals of goethite were synthesized with reduced technetium [{sup 99}Tc(IV)] incorporated within the solid lattice. The presence of {sup 99}Tc(IV) as a substituting cation in the matrix and 'armoring' by an additional layer of precipitated goethite isolated the reduced {sup 99}Tc(IV) from oxidizing agents. These products were used to make monolithic pellets to quantify an effective diffusion coefficient for {sup 99}Tc from goethite waste form contacted with a synthetic Hanford IDF (integrated disposal facility) pore water solution (pH = 7.2, I = 0.05 M) at room temperature for up to 120 days in static reactors. XANES analysis of the goethite solids recovered post-run demonstrated that the {sup 99}Tc in the goethite crystals remains in the reduced {sup 99}Tc(IV) state. The slow release of pertechnetate concentration with time in the static experiments with the monolith followed a square root of time dependence, consistent with diffusion control for {sup 99}Tc release. An apparent diffusion coefficient of 6.15 x 10{sup -11} cm{sup 2}/s was calculated for the {sup 99}Tc-goethite pellet sample and the corresponding leaching index (LI) was 10.2. The results of this study indicate that technetium can be immobilized in a stable, low-cost Fe oxide matrix that is easy to fabricate and these findings can be useful in designing long-term solutions for nuclear waste disposal.

Um, Wooyong; Chang, Hyun-Shik; Icenhower, Jonathan P.; Lukens, Wayne W.; Serne, R. Jeffrey; Qafoku, Nikolla; Kukkadapu, Ravi K.; Westsik, Joseph H.

2012-06-09

125

High Pressure Study on Some HIGH-Tc Superconductors  

NASA Astrophysics Data System (ADS)

We present a brief review on the pressure effects of some high temperature super-conductors. The examined systems include RBa2Cu3O7, (R, Pr)Ba2Cu3O7 and (ZnPc)yBi2Sr2Ca2Cu3O10, with R=rare earth elements and Pc=phthalocyanine. The results of the presssure effects on the superconducting transition temperature Tc in these materials have, thus, not only revealed the origin of the Tc-variation induced by the chemical substitution or intercalation, but have also confirmed the important roles played by the carrier concentration and Tco (maximum Tc) on determining Tc. Based on our experimental results, along with good agreement between our data and theory, we have clearly demonstrated that the variation of Tc dominantly originates from the strains induced by the variation of the ionic radii or the intercalation of foreign molecules.

Huang, C. Y.; Lin, J. G.; Huang, Z. J.

126

Nuclear quadrupole moment of the {sup 99}Tc ground state  

SciTech Connect

By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2{sup +} ground state of {sup 99}Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc{sub 2} and ZrTc{sub 2}. If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the {sup 99}Tc ground state quadrupole moment could be further reduced.

Errico, Leonardo [Departamento de Fisica and Instituto de Fisica La Plata (IFLP, CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Coreo 67, 1900 La Plata (Argentina); Universidad Nacional del Noroeste Bonaerense (UNNOBA), Monteagudo 2772, 2700 Pergamino (Argentina); Darriba, German; Renteria, Mario [Departamento de Fisica and Instituto de Fisica La Plata (IFLP, CCT-La Plata, CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Coreo 67, 1900 La Plata (Argentina); Tang Zhengning [Bayerisches Geoinstitut, Universitaet Bayreuth, DE-95440 Bayreuth (Germany); Emmerich, Heike [Computational Materials Engineering (CME), Institute for Minerals Engineering (GHI), Center for Computational Engineering Science - CCES and Juelich-Aachen Research Alliance - JARA, RWTH Aachen University, DE-52064 Aachen (Germany); Cottenier, Stefaan [Computational Materials Engineering (CME), Institute for Minerals Engineering (GHI), Center for Computational Engineering Science - CCES and Juelich-Aachen Research Alliance - JARA, RWTH Aachen University, DE-52064 Aachen (Germany) and Instituut voor Kern-en Stralingsfysica and INPAC, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, BE-3001 Leuven (Belgium)

2008-05-15

127

Bond ionicities of high-Tc oxides  

NASA Astrophysics Data System (ADS)

A semiempirical method for the calculation of the bond ionicity, which is applicable even to extremely anisotropic systems such as copper-oxide superconductors, is proposed as a generalization of the Phillips-Van Vechten-Levine scheme. The value of the ionicity calculated for oxides generally tends to increase as the crystal strain becomes more tensile. It is characteristic of cuprate superconductors that the values of the ionicity are high compared with other 3d transition-metal oxides. Also significant are the extremely high ionicities in the direction normal to the CuO2 planes and the relatively high covalencies of the intraplanar bonds. These crystal-chemical characteristics may be intimately related to the remarkable insulator-to-metal transition and the associated high-Tc superconductivity in the layered copper-oxide systems.

Tanaka, Shigenori

1994-02-01

128

The recovery of asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

On October 7, 2008, asteroid 2008 TC3 impacted Earth and fragmented at 37 km altitude above the Nubian Desert in northern Sudan. The area surrounding the asteroid's approach path was searched, resulting in the first recovery of meteorites from an asteroid observed in space. This was also the first recovery of remains from a fragile "cometary" PE = IIIa/b type fireball. In subsequent searches, over 600 mostly small 0.2-379 g meteorites (named "Almahata Sitta") with a total mass 10.7 kg were recovered from a 30 × 7 km area. Meteorites fell along the track at 1.3 kg km-1, nearly independent of mass between 1 and 400 g, with a total fallen mass of 39 ± 6 kg. The strewn field was shifted nearly 1.8 km south from the calculated approach path. The influence of winds on the distribution of the meteorites, and on the motion of the dust train, is investigated. The majority of meteorites are ureilites with densities around 2.8 g cm-3, some of an anomalous (porous, high in carbon) polymict ureilite variety with densities as low as 1.5 g cm-3. In addition, an estimated 20-30% (in mass) of recovered meteorites were ordinary, enstatite, and carbonaceous chondrites. Their fresh look and matching distribution of fragments in the strewn field imply that they were part of 2008 TC3. For that reason, they are all referred to as "Almahata Sitta." No ureilite meteorites were found that still held foreign clasts, suggesting that the asteroid's clasts were only loosely bound.

Shaddad, Muawia H.; Jenniskens, Peter; Numan, Diyaa; Kudoda, Ayman M.; Elsir, Saadia; Riyad, Ihab F.; Ali, Awad Elkareem; Alameen, Mohammed; Alameen, Nada M.; Eid, Omer; Osman, Ahmed T.; Abubaker, Mohamed I.; Yousif, Mohamed; Chesley, Steven R.; Chodas, Paul W.; Albers, Jim; Edwards, Wayne N.; Brown, Peter G.; Kuiper, Jacob; Friedrich, Jon M.

2010-10-01

129

Tc and Re behavior in borosilicate waste glass vapor hydration tests II  

NASA Astrophysics Data System (ADS)

Technetium (99Tc) is a significant environmental risk factor to consider for nuclear waste disposal repositories. Rhenium (Re), in the same column of the periodic table as Tc, is often used as a non-radioactive surrogate for Tc. Six waste glasses containing both Tc and Re were synthesized under a variety of redox conditions to produce different distributions of Tc and Re oxidation states. These glasses were exposed to vapor hydration tests (VHT) at 200 °C for 23 to 30 days; and the Tc and Re oxidation state, coordination environment, and spatial distribution within the altered coupons were determined. Compared with the original glasses, the corresponding VHT samples showed substantial reduction of Tc species, except where the original glass contained only reduced Tc (Tc4+). Similar to earlier findings, Tc is more sensitive to redox conditions than Re with respect to both glass synthesis conditions and VHT alteration processes. Glasses that originally contained more oxidized Tc (near 100% Tc7+) showed the most Tc enrichment in the altered VHT sample layers, where Tc was largely reduced to Tc4+. Re is generally more oxidized than Tc in the samples measured and has similar spatial distributions as Tc in some VHT samples, while having very different spatial distributions compared with Tc in others. Glasses that originally had a distribution of Tc oxidation states (approximately 1:1 Tc4+ to Tc7+), had Tc concentrations in the VHT altered layers that were approximately equal to or less than those found in the unaltered glass. However, in the same samples, Re concentrations were highest in the altered layers. Overall, with regard to spatial distributions within the altered VHT layers, the behavior of Re was not a good predictor of Tc behavior. Therefore, at least under VHT conditions, using Re as a non-radioactive surrogate for Tc in borosilicate waste glasses can provide misleading results.

Buechele, Andrew C.; McKeown, David A.; Lukens, Wayne W.; Shuh, David K.; Pegg, Ian L.

2012-10-01

130

In Vivo Evaluation Of 99mTc-DTPA and 99mTc-Sulphur Colloid as Tracers In Colonic Drug Delivery Systems Using Gamma Scintigraphy In Volunteers  

Microsoft Academic Search

PURPOSE: The suitability of 99mTc-dieth- ylenetriaminepenta- acetic acid (DTPA) and 99mTc-sulphur colloid (99mTc-SC) as tracers in gamma Scintigraphy for the evaluation of colon-specific drug delivery systems was assessed in healthy volunteers. METHOD: Sodium chlo- ride core tablets containing either 99mTc-DTPA or 99mTc- SC were prepared and compression coated with two dif- ferent quantities of guar gum. The compression-coated tablets were

Y. S. R. Krishnaiah; S. Satyanarayana; Y. V. Rama Prasad; S. Narasimha Rao

131

Comparative quality control of 99m Tc-Pyrophosphate and 99m Tc-diphosphonate radiopharmaceuticals  

Microsoft Academic Search

The results of analysis of 99mTc-Pyrophosphate (99mPyP), taken as a representative of the group of compounds having an organic P-O-P bond, and of the three diphosphonate compounds: methylene diphosphonate (MDP), 2,3-dicarboxy propane diphosphonate (DPD) and ethane-1-hydroxy-1, 1-diphosphonate (EHDP), which differ in their chemical structure, are shown. Also, some physicochemical parameters such as chloroform-water apparent partition coefficient, the osmotic pressure and

V. Jovanovi?; T. Maksin; M. Rastovac; J. Bzeni?

1983-01-01

132

Power Systems Development Facility Gasification Test Campaign TC21  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coal. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a Transport Gasifier, a hot gas particulate control device (PCD), advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of the first demonstration of gasification operation with lignite coal following the 2006 gasifier configuration modifications. This demonstration took place during test campaign TC21, occurring from November 7, 2006, through January 26, 2007. The test campaign began with low sodium lignite fuel, and after 304 hours of operation, the fuel was changed to high sodium lignite, for 34 additional hours of operation. Both fuels were from the North Dakota Freedom mine. Stable operation with low sodium lignite was maintained for extended periods, although operation with high sodium lignite was problematic due to agglomeration formation in the gasifier restricting solids circulation.

Southern Company Services

2007-01-30

133

Power Systems Development Facility Gasification Test Campaign TC17  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR (formerly Kellogg Brown & Root) Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results gasification operation with Illinois Basin bituminous coal in PSDF test campaign TC17. The test campaign was completed from October 25, 2004, to November 18, 2004. System startup and initial operation was accomplished with Powder River Basin (PRB) subbituminous coal, and then the system was transitioned to Illinois Basin coal operation. The major objective for this test was to evaluate the PSDF gasification process operational stability and performance using the Illinois Basin coal. The Transport Gasifier train was operated for 92 hours using PRB coal and for 221 hours using Illinois Basin coal.

Southern Company Services

2004-11-30

134

Measurement of Tc suppression in tungsten using magnetic impurities  

NASA Astrophysics Data System (ADS)

We have measured the effects of dilute magnetic-atom doping on the superconducting transition temperature of tungsten thin films. Our ``Tc tuning'' technique is accurate, precise, and simple. Experiments were performed using dc-magnetron-sputtered tungsten films with undoped values of Tc in the range of 70-150 mK. The magnetic-atom doping was achieved using ion implantation. Specific Tc suppressions of between 5% and 65% were targeted and observed in this study. The transition width of each undoped sample was ~1 mK and the transition widths remained sharp after implantation with 56Fe+ ions. Our data are in good agreement with predictions of a linear dependence of Tc suppression with increasing magnetic-atom concentration, in the small concentration limit. At higher concentrations, antiferromagnetic coupling between the magnetic dopant atoms becomes important and the Tc-suppression effect is diminished. We use our Tc data to calculate the Abrikosov-Gor'kov (AG) and Ruderman-Kittel-Kasuya-Yosida (RKKY) spin-flip relaxation parameters ?AG and ?RKKY. We conclude with a brief discussion of applications of the Tc-tuning technique, and present our plans for future studies in this area.

Young, B. A.; Saab, T.; Cabrera, B.; Cross, J. J.; Clarke, R. M.; Abusaidi, R. A.

1999-12-01

135

Double Star Probe TC-1 measurements of microscopic Electron Dynamics near the Van Allen Radiation Belts  

NASA Astrophysics Data System (ADS)

Intense kHz waves generated by electron cyclotron resonance are often observed by the STAFF instrument on the TC-1 Double Star spacecraft These electromagnetic waves with frequencies below fce are thought to be associated with the diffuse aurora together with higher frequency electrostatic electron cyclotron harmonic waves As part of the DWP instrumentation on board the Double Star Equator TC-1 spacecraft a particle correlator experiment operates which directly captures time series of electron counts provided by the PEACE HEEA sensor over the energy range from a few eV to 20 keV using high sampling frequencies 1 4 to 41 kHz One novelty of the DSP correlator is that in addition to producing summed Auto-Correlation Functions ACFs from these time series it also has the ability to transmit successive compressed time series of the actual electron counts individual time series being approximately of millisecond duration These time series reveal individual electrons being detected with separations of the order of tens of microseconds and hence retain the phase as well as frequency information for the interaction of the electrons with the waves Measurements are presented of the DSP TC-1 particle correlator data in conjunction with other DSP data for passes close to perigee which link wave emissions to microscopic bunching in the electron population

Buckley, A. M.; Yearby, K.; Carozzi, T. D.; Gough, M. P.; Alleyne, H.

136

Distributed production system for {sup 99m}Tc-I: System overview  

SciTech Connect

Technetium-99m is the radioisotope of choice for >80% of all nuclear medical imaging procedures today in the United States. There are > 12 million {sup 99m}Tc scans performed in the United States per year. Since the development of fission-based radio nuclide generators for {sup 99}Mo, {sup 99m}Tc use has grown steadily over the past 20 yr. Despite the widespread demand for {sup 99m}Tc in medicine, a reliable and assured supply of the parent, {sup 99}Mo, does not exist. Construction of Maple-1 and -2, two new Canadian isotope production reactors intended to replace the aging National Research Universal (NRU) reactor, has been approved in an agreement among Atomic Energy of Canada Limited, MDS Nordion, and the Canadian government. However, the project is expensive: The anticipated cost of Maple-1 and -2 is $C140 million. Outlays toward this cost have recently driven the price of {sup 99}Mo up by 40%, even though the Canadian {sup 99}Mo production will continue to be heavily subsidized by an interest-free construction loan. Research and development for an accelerator-based facility has been undertaken and is described.

Bennett, R.G.; Terry, W.K.; Grover, S.B. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States)

1997-12-01

137

(99m)Tc-labeled therapeutic inhaled amikacin loaded liposomes.  

PubMed

Abstract The radiolabeling of the liposome surface can be a useful tool for in vivo tracking of therapeutic drug loaded liposomes. We investigated radiolabeling therapeutic drug (i.e. an antibiotic, amikacin) loaded liposomes with (99m)Tc, nebulization properties of (99m)Tc-labeled liposomal amikacin for inhalation ((99m)Tc-LAI), and its stability by size exclusion low-pressure liquid chromatography (LPLC). LAI was reacted with (99m)Tc using SnCl2 dissolved in ascorbic acid as a reducing agent for 10?min at room temperature. The labeled products were then purified by anion exchange resin. The purified (99m)Tc-LAI in 1.5% NaCl solution was incubated at 4?°C to assess its stability by LPLC. The purified (99m)Tc-LAI was subjected to studies with a clinically used nebulizer (PARI eFlow®) and the Anderson Cascade Impactor (ACI). The use of ascorbic acid at 0.91?mM resulted in a quantitative labeling efficiency. The LPLC profile showed that the liposomal peak of LAI detected by a UV monitor at both 200?nm and 254?nm overlapped with the radioactivity peak of (99m)Tc-LAI, indicating that (99m)Tc-LAI is suitable for tracing LAI. The ACI study demonstrated that the aerosol droplet size distribution determined gravimetrically was similar to that determined by radioactivity. The liposome surface labeling method using SnCl2 in 0.91?mM ascorbic acid produced (99m)Tc-LAI with a high labeling efficiency and stability that are adequate to evaluate the deposition and clearance of inhaled LAI in the lung by gamma scintigraphy. PMID:23879241

Lee, Jae-Ho; Cheng, Kenneth T; Malinin, Vladimir; Li, Zhili; Yao, Zhengsheng; Lee, Sung-Jin; Gould, Christine M; Olivier, Kenneth N; Chen, Clara; Perkins, Walter R; Paik, Chang H

2013-07-24

138

Electron tunneling in the high-Tc bismuthate superconductors  

NASA Astrophysics Data System (ADS)

We have performed extensive tunneling measurements on some high-Tc superconducting oxides of bismuth: BaPb1-xBixO3, Ba1-xRbxBiO3, and Ba1-xKxBiO3. The results on high-quality single crystals and epitaxial films indicate that these materials are weak-coupled superconductors with 2?/kTc=3.5+/-0.3. The observed quasiparticle excitation spectrum agrees with the BCS model. We also do not observe structure indicating electron-phonon coupling sufficiently strong to account for the Tc of these materials.

Sharifi, F.; Pargellis, A.; Dynes, R. C.; Miller, B.; Hellman, E. S.; Rosamilia, J.; Hartford, E. H., Jr.

1991-12-01

139

Biogeochemical Coupling of Fe and Tc Speciation in Subsurface Sediments: Implications to Long-Term Tc Immobilization  

SciTech Connect

The overall project has been investigating the reactivity of pertechnetate [Tc(VII)] with Fe(II) forms in model mineral and mineral-microbe systems, and with sediments from the Oak Ridge FRC and the Hanford site. Past project results with Hanford and Oak Ridge sediments have been published in Fredrickson et al., (2004) and Kukkadapu et al., (2006). This poster summarizes a series of model system experiments that investigates whether microbes or biogenic Fe(II) were more important in the reduction of Tc(VII) in an anoxic suspension of ferrihydrite, Shewanella oneidensis MR-1, Tc(VII), and electron donor. Ferrihydrite is used to represent a bioavailable Fe(III) oxide present in small amounts in Oak Ridge and Hanford sediments. In order to address this overall goal, Tc(VII) reduction rates and redox products were studied in less complex systems where individual abiotic and biotic reactions were isolated for rigorous characterization. The specific objectives of the individual experiments in the series were as follows: (1) Identify the rates and products of the reaction of Tc(VII) with aqueous Fe(II) at circumneutral pH values (homogeneous reduction). (2) Identify the rates and products of the reaction of Tc(VII) with surface complexed Fe(II) on goethite and hematite in the circumneutral pH range (heterogeneous reduction). (3) Identify the rates and products of the reaction of Tc(VII) with MR-1 under anoxic conditions individually with hydrogen and lactate as electron donors (biologic reduction). (4) Use insights from the above experiments to determine which of the three above, potentially parallel reactions determine the final speciation of Tc in a mixture of ferrihydrite, respiring MR-1, and Tc(VII).

Zachara, John M.; Kukkadapu, Ravi K.; Heald, Steve M.; McKinley, James P.; Dohnalkova, Alice C.; Fredrickson, James K.; Byong-Hun Jeon

2006-04-05

140

A correlative study between 99mTc-ESTCPTA and 99mTc-MIBI in rats  

Microsoft Academic Search

Tissue distribution of the 99mTc labeled derivative of the estrogen compound 3,17-?-estradiolyl propyl 1,4,8,11-tetraazacyclotetradecanyl-1-(4-methylbenzoic acid) ester (ESTCPTA), which has an 3,17-?-estradiolyl propinol coupled to 1-(4-methylbenzoic acid)1,4,8,11-tetraazacyclotetradecane (CPTA), was compared to 99mTc-MIBI (methoxyisobutyl isonitrile) in female Albino Wistar rats. Tissues of interest included lung, liver, heart, kidneys, spleen, stomach, intestines, pancreas, muscle, blood, breast, ovary, fat, and uterus. 99mTc-ESTCPTA uptake by

Perihan Unak; Huseyin Enginar; F. Zümrüt Biber; Fatma Yurt Lambrecht; Mahmoud A. A. Aslani; Hayal Ozkilic

2002-01-01

141

Nonaqueous Suspension Spinning of High-Tc Ba-Y-Cu-O Superconductor  

NASA Astrophysics Data System (ADS)

The preparation of a high-Tc Ba2Y1Cu3Ox superconducting filament was studied by nonaqueous suspension spinning. The fine powder of the oxide was suspended in PVA dimethyl sulfoxide solution containing a dispersant. The viscous suspension was extruded as a filament into a precipitating medium of methyl alcohol and coiled on a winding drum. The obtained filament, 200 ?m in diameter, was heated to remove volatile components and to generate the layered perovskite phase. The heated filament with tensile strength of 37 MPa was a superconductor at 84 K and had a Jc value of 680 A/cm2 at 77 K.

Goto, Tomoko

1988-04-01

142

Labeling of famotidine with 99m Tc and biodistribution studies on rats  

Microsoft Academic Search

Famotidine, a gastrointestinal drug was labeled with 99mTc and its radiopharmaceutical potential was observed on male Albino Wistar rats. Labeling yield was over 95%. Average specific\\u000a activity and n-octanol\\/water partition coefficient (lipophilicity) were approximately 74 MBq\\/mg-0.66 GBq\\/mg and 3.4, respectively.\\u000a Biodistribution studies were performed on Albino Wistar rats. The activity per gram tissue was calculated and time-activity\\u000a curves were generated.

P. Unak; F. Y. Lambrecht; F. Z. Biber; ?. E. Medine; S. Teksoz

2004-01-01

143

Electron Microscopy Characterization of Tc-Bearing Metallic Waste Forms- Final Report FY10  

SciTech Connect

The DOE Fuel Cycle Research & Development (FCR&D) Program is developing aqueous and electrochemical approaches to the processing of used nuclear fuel that will generate technetium-bearing waste streams. This final report presents Pacific Northwest National Laboratory (PNNL) research in FY10 to evaluate an iron-based alloy waste form for Tc that provides high waste loading within waste form processing limitations, meets waste form performance requirements for durability and the long-term retention of radionuclides and can be produced with consistent physical, chemical, and radiological properties that meet regulatory acceptance requirements for disposal.

Buck, Edgar C.; Neiner, Doinita

2010-09-30

144

Representability of METT-TC Factors in JC3IEDM.  

National Technical Information Service (NTIS)

Commanders require relevant information about background information in order to exercise effective command and control (C2). METT-TC factors (Mission, Enemy, Terrain & Weather, Troops, Time Available and Civil Considerations) represent the canonical, mil...

B. Ulicny C. Matheus G. Powell M. Kokar R. Dionne

2007-01-01

145

Comparison of the Results for Sentinel Lymph Node Mapping in the Breast Cancer Patients using 99mTc-Antimony Trisulfide Colloid, 99mTc-Tin Colloid, and 99mTc-Human Serum Albumin  

Microsoft Academic Search

lymph node mapping. Subjects and Methods: Totally, 397 patients with clinically N0 stage were enrolled. 99m Tc-ASC was injected in 202 out of 397 patients, 99m Tc-TC was injected in 120 patients, and 99m Tc-HSA was injected in the remaining 75 patients. The sentinel lymph nodes were localized by lymphoscintigraphy and selected using intraoperative gamma probe. All sentinel lymph nodes

Tc-Tin Colloid; Sung-June Jang; Seung Hwan Moon; Seok-Ki Kim; Bom Sahn Kim; Seok Won Kim; Ki-Wook Chung; Eun Sook Lee; Keon Wook Kang

146

Tumbleweed and Cheatgrass Uptake of exp 99 TC from Five Hanford Soils.  

National Technical Information Service (NTIS)

The accumulation of technetium (Tc) by tumbleweed and cheatgrass was measured for five Hanford Project soils at the initial soil concentration of 1.0 pg/g of exp 99 Tc traced by /sup 95m/Tc at one, two, and three months' harvest times. Tc was added to the...

R. C. Routson D. A. Cataldo

1977-01-01

147

Abnormal Tc99m sulesomab in Klippel-Trenaunay syndrome.  

PubMed

Tc-99m sulesomab is indicated in bone and joint infection, but reading of scans can be affected by pre-existing conditions. This case report describes a case of Klippel-Trenaunay syndrome (KTS) which results in vascular malformations of one or more limbs. Tc-99m sulesomab imaging demonstrated persistent blood pool activity up to 20 hours post injection. However, despite this, septic arthritis could be identified with confidence in the same limb. PMID:21598233

Begum, Shabina; Nowosinska, Ewa; Buscombe, John R

2010-01-01

148

Renal artery stenosis diagnosed with Tc-99m DMSA scintigraphy.  

PubMed

Captopril-enhanced renal scintigraphy with Tc-99m DMSA was performed in an 11-year-old boy with hypertension. This showed a significant reduction in function of the right kidney. Renal arteriography was performed and showed two renal arteries on the right, the major one with stenosis. This case illustrates the possible role that scintigraphy with Tc-99m DMSA can play in the diagnosis of renovascular hypertension. PMID:8137578

de Hollanda, R; Giamberardino, D D; Bley, P C; Sandrini, R A; Kanegusukus, J

1994-01-01

149

Sorption of99mTc radiopharmaceutical compounds by soils  

USGS Publications Warehouse

Study of the sorption of 99mTc radiopharmaceutical compounds by soils has assessed the fate of these compounds in the event of a surface spill and examined the potential of these compounds as hydrologic tracers. Sorption from deionized water, filtered Missouri River water, and artificial seawater by five surface soils was investigated. For all water types, the Tc radiopharmaceutical compounds showed greater sorption than the uncomplexed pertechnetate. The most lipophilic complexes showed the highest sorption on soils.

Jurisson, S.; Gawenis, J.; Landa, E. R.

2004-01-01

150

Treatment Outcomes for Women in Prison-Based TC Programs  

Microsoft Academic Search

in the TC had significantly lower rearrest rates (18%) compared with 29% of the 113 women who participated in other types of prison-based programs (e.g., counseling and milieu therapy). The women' s TC group also had a significantly higher percentage who were positively discharged from parole (77%) compared with 53% of the 38 women in the no-treatment control group (i.e.,

James A. Inciardi; Mary Beth Johnson; Marie F. Ragghianti; Chevy Chase; Liz Stanley-Salazar; Dwayne Simpson

151

99m-Tc-Tetrofosmin Scintigraphy and Breast Cancer  

Microsoft Academic Search

Background.99m-Tc-tetrofosmin holds significant interest among medical oncologists because of its high positive predictive value (>90%) in pilot trials, exceeding sensitivity and specificity rates of mammography.Objective.Our objective was to assess the diagnostic accuracy of 99m-Tc-tetrofosmin whole-body scintigraphy in outpatients.Patients and methods.Thirty-one patients with an abnormal mammograph (n= 22) or follow-up patients (n= 9), 7 of whom were known to have metastatic

Peter Berghammer; Reinhard Obwegeser; Silvia Müllauer-Ertl; Georgios Karanikas; Christoph Wiltschke; Ernst Kubista; Helmut Sinzinger; Christoph Zielinski

1999-01-01

152

Magnesium potassium phosphate ceramic for 99Tc immobilization  

Microsoft Academic Search

Technetium-99, present in the US Department of Energy's (DOE) high-level waste (HLW) as a by-product of fission reactions, poses a serious environmental threat because it has a long half-life, is highly mobile in its soluble Tc7+ oxidation state and is volatile at high temperatures. Magnesium potassium phosphate (MKP) ceramics have been developed to treat 99Tc that has been partitioned and

D. Singh; V. R. Mandalika; S. J. Parulekar; A. S. Wagh

2006-01-01

153

Magnesium potassium phosphate ceramic for 99Tc immobilization  

Microsoft Academic Search

Technetium-99, present in the US Department of Energy’s (DOE) high-level waste (HLW) as a by-product of fission reactions, poses a serious environmental threat because it has a long half-life, is highly mobile in its soluble Tc7+ oxidation state and is volatile at high temperatures. Magnesium potassium phosphate (MKP) ceramics have been developed to treat 99Tc that has been partitioned and

D. Singh; V. R. Mandalika; S. J. Parulekar; A. S. Wagh

2006-01-01

154

Solvent Extraction of Tc and Cs from Alkaline Nitrate Wastes  

SciTech Connect

This paper summarizes progress at three collaborating U.S. national laboratories on the extraction of the fission products 99Tc and 137Cs from alkaline high-level wastes. Efficient economical processes for Tc and Cs extraction (SRTALK and alkaline-side CSEX, respectively) have been developed, and testing has progressed through batch tests on actual wastes and continuous counter-current centrifugal-contactor tests on simulants.

Moyer, Bruce A. (OAK RIDGE NATIONAL LAB); Bonnesen, Peter V. (ORNL); Delmau, Laetitia H. (OAK RIDGE NATIONAL LAB); Haverlock, T J. (Oak Ridge National Laboratory); Sachleben, R A. (Oak Ridge National Laboratory); Leonard, R A. (Argonne National Laboratory); Conner, C (Argonne National Laboratory); Lumetta, Gregg J. (BATTELLE (PACIFIC NW LAB)); M. Cox, M. Hidalgo, and M. Valiente

2001-01-01

155

The Rise of Tc: A Promising Paradigm via Interfacial Mechanism  

NASA Astrophysics Data System (ADS)

Following the seminal detection of superconductivity at 35 K in the first cuprate high temperature superconductor Ba-doped ternary LCO (La214) by Mueller and Bednorz in 1986, the discovery of the first liquid nitrogen superconductor quaternary YBCO (Y123) with a transition temperature Tc of 93 K by Chu, Wu, and colleagues in 1987 has ushered in the modern era of high temperature superconductivity (HTS). In the ensuing 25 years, great progress has been made in all areas of HTS research and development, from materials to physics to devices. However, the Tc remains at 134 K in quaternary HBCCO (Hg1223) at ambient pressure achieved in 1993 by Schilling et al. and at 164 K in the same compound under high pressure in the same year by Gao et al. A holistic multidisciplinary enlightened empirical approach has been proposed to search for superconductors with higher Tc, which includes the discovery of new compounds empirically and the realization of novel mechanisms proposed by theorists. Recently, we have observed nonbulk superconductivity in single crystalline rare-earth doped Ca122 samples with an onset Tc of 49 K, higher than the Tc of any known compounds formed of the constituent elements at ambient or under high pressures. Subsequent systematic structural, electrical, magnetic, and calorimetric investigations suggest that the observation may be attributed to an interface-induced Tc, thus suggesting a possible new paradigm for higher Tc. In this presentation, our results will be presented and discussed, following a brief recollection of a few events in our lab in the continuing search for higher Tc, even though a number of review articles have appeared.

Chu, C. W.; Lv, B.; Deng, L. Z.; Lorenz, B.; Jawdat, B.; Gooch, M.; Shrestha, K.; Zhao, K.; Zhu, X. Y.; Xue, Y. Y.; Wei, F. Y.

2013-07-01

156

Cross-sections for formation of 99mTc through natRu(n,x) 99mTc reaction induced by neutrons at 13.5 and 14.8 MeV  

NASA Astrophysics Data System (ADS)

The cross-sections for formation of metastable state of 99Tc (99mTc, 140.511 keV, 6.01 h) through natRu(n,x)99mTc reaction induced by 13.5 MeV and 14.8 MeV neutrons were measured. Fast neutrons were produced via the 3H(d,n)4He reaction on the K-400 neutron generator. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with a high-purity germanium (HpGe) detector. Measurements were corrected for gamma-ray attenuations, dead time and fluctuation of neutron flux. Data for natRu(n,x)99mTc reaction cross sections are reported to be 9.6±1.5 and 9.2±1.1 mb at 13.5±0.2 and 14.8±0.2 MeV incident neutron energies, respectively. Results were compared with the data by other anthors.

Luo, Junhua; Han, Jiuning; Tuo, Fei; Kong, Xiangzhong; Liu, Rong; Jiang, Li

2012-05-01

157

CD8Tc1 and Tc2 cells secrete distinct cytokine patterns in vitro and in vivo but induce similar inflammatory reactions.  

PubMed

Naive CD8 T cells, similar to CD4 T cells, can differentiate into at least two subsets of cytolytic effector cells with distinct cytokine patterns: T cytotoxic-1 (Tc1) cells secrete a Th1-like cytokine pattern, including IL-2 and IFN-gamma; and Tc2 cells produce Th2 cytokines, including IL-4, IL-5, and IL-10. As CD4 Th1 cells induce delayed-type hypersensitivity (DTH) more effectively than Th2 cells, we tested the potential ability of Tc1 and Tc2 cells to induce DTH. Allospecific Tc1 or Tc2 cells were injected into the footpads of naive mice expressing the target Ag. Tc1 and Tc2 cells induced comparable levels of Ag-specific footpad swelling with similar kinetics. They also induced similar levels of footpad edema and similar infiltration of macrophages and neutrophils. However, Tc2 cells induced slightly more eosinophil infiltration. Analysis of footpad extracts showed that Tc1 and Tc2 cells retained their distinct in vitro cytokine profiles in the injected footpads. These results suggest that both Tc1 and Tc2 cytokines can be associated with the DTH reaction induced by CD8 T cells. Perforin-deficient Tc1 or Tc2 cells also induced DTH, although at lower levels, suggesting that perforin-mediated cytotoxicity of CD8 T cells is not essential for CD8-induced DTH. Thus, despite their distinct cytokine profiles in vitro and in vivo, Tc1 and Tc2 cells induce similar DTH reactions. PMID:9126975

Li, L; Sad, S; Kägi, D; Mosmann, T R

1997-05-01

158

Bond-valence sums for Tc–O systems from EXAFS data  

Microsoft Academic Search

Literature data for structures containing exclusively Tc–O bonds were used to calculate unit-valence parameters R0 for Tc(VII), Tc(VI), Tc(V) (five-coordinate), Tc(V) (six-coordinate), Tc(IV) and Tc(III) as 1.909, 1.955, 1.870, 1.859, 1.841 and 1.768 Å, respectively. A second method of estimating R0 was developed to validate the calculated values for these oxidation states because crystallographic data are limited. The method was

Dennis W. Wester; Nancy J. Hess

2005-01-01

159

Intron 2 (T\\/C) CYP46 Polymorphism Is Associated with Alzheimer’s Disease in Chinese Patients  

Microsoft Academic Search

Background: Cholesterol metabolism has been implicated in the pathophysiology of Alzheimer’s disease (AD), and cholesterol-related genes are plausible candidate genes for AD. Genetic association of CYP46A1 polymorphisms with AD had been under extensive investigations; however, observations on intron 2 T?C (rs754203) generated inconclusive results. Objective: To analyse an independent data set in a Chinese population to see whether the polymorphic

Y. Li; L. W. Chu; Y. Q. Chen; B. M. Y. Cheung; R. Y. H Leung; P. Y. Yik; K. M. Ng; W. Mak; D. Y. Jin; P. St. George-Hyslop; Y. Q. Song

2006-01-01

160

Quantitative assessment of soil parameter (KD and TC) estimation using DGT measurements and the 2D DIFS model.  

PubMed

Diffusive gradients in thin films (DGT) is a dynamic, in situ measuring technique that can be used to supply diverse information on concentrations and behaviour of solutes. When deployed in soils and sediments, quantitative interpretation of DGT measurements requires the use of a numerical model. An improved version of the DGT induced fluxes in soils and sediments model (DIFS), working in two dimensions (2D DIFS), was used to investigate the accuracy with which DGT measurements can be used to estimate the distribution coefficient for labile metal (KD) and the response time of the soil to depletion (TC). The 2D DIFS model was used to obtain values of KD and TC for Cd, Zn and Ni in three different soils, which were compared to values determined previously using 1D DIFS for these cases. While the 1D model was shown to provide reasonable estimates of KD, the 2D model refined the estimates of the kinetic parameters. Desorption rate constants were shown to be similar for all three metals and lower than previously thought. Calculation of an error function as KD and TC are systematically varied showed the spread of KD and TC values that fit the experimental data equally well. These automatically generated error maps reflected the quality of the data and provided an appraisal of the accuracy of parameter estimation. They showed that in some cases parameter accuracy could be improved by fitting the model to a sub-set of data. PMID:18035392

Lehto, N J; Sochaczewski, L; Davison, W; Tych, W; Zhang, H

2007-11-26

161

Quasiparticle tunneling spectroscopy of high {Tc} cuprates  

SciTech Connect

Superconductor-insulator-normal metal (SIN) and superconductor-insulator-superconductor (SIS) tunnel junctions provide important information on pairing state symmetry and mechanism. Measurements of such junctions on high {Tc} superconductors (HTS) are reported using mechanical point contacts, which generally display the optimum characteristics that can be obtained from HTS native-surface tunnel barriers. New tunneling data on the infinite-layer cuprate, Sr{sub 1{minus}x}Nd{sub x}CuO{sub 2} are reported which show a remarkable similarity to another electron-doped cuprate, Nd{sub 1.85}Ce{sub 0.85}CuO{sub 4}. In particular, there is a strong, asymmetric linear background conductance that is indicative of inelastic tunneling from a continuum of states. A discussion is given of the anomalous dip feature found in the tunneling and photoemission data on BSCCO 2212. It is shown that a similar feature is found in many cuprate junctions and that this dip scales with the gap energy over a wide range. New data on the single-layer, tetragonal cuprate, Tl{sub 2}Ba{sub 2}CuO{sub 6} (Tl2201) are presented and discussed in light of recent published results on the similar compound HgBa{sub 2}CuO{sub 4} (Hg1201). The HG1201 data display a low, flat sub-gap tunneling conductance which is consistent with a BCS density of states whereas the T12201 data display a cusp-like feature at zero bias which is more consistent with d{sub x}2-{sub y}2 symmetry.

Zasadzinski, J.; Ozyuzer, L.; Yusof, Z. [Illinois Inst. of Tech., Chicago, IL (United States); Chen, J.; Gray, K.E.; Mogilevsky, R.; Hinks, D.G. [Argonne National Lab., IL (United States). Materials Science Div.; Cobb, J.L.; Markert, J.T. [Univ. of Texas, Austin, TX (United States)

1996-04-01

162

A clinical comparison of 99m Tc-DPD and two 99m Tc-MDP agents  

Microsoft Academic Search

Two hundred and fifty-seven patients were studied with bone-seeking radiopharmaceuticals. They were randomly divided into three groups. Two groups were injected with two different 99mTc-methylene diphosphonates from two manufactures (MDP 1 and MDP 2) and the third group with 99mTc-dicarboxypropane diphosphonate (DPD). DPD was found to be superior with respect to blood clearance, femur to soft tissue ratio and subjectively

M. Vorne; S. Vähätalo; T. Lantto

1983-01-01

163

A comparison of bone imaging with Tc99m DPD and Tc99m MDP: concise communication  

Microsoft Academic Search

Bone to soft tissue (ST) ratios for both high-uptake bone (sacrum) and low-uptake bone (femoral diaphysis) were obtained with a derivative of phosphonic acid, TC-99m 2,3-dicarboxypropane-1, 1-diphosphonate (DPD), in 26 normal subjects and 177 patients with malignant disease but without metastases. Tests were run 2 hr after tracer injection. Similar ratios were obtained with Tc-99m methylene diphosphonate (MDP) in 220

U. Buell; E. Kleinhans; E. Zorn-Bopp; W. Reuschel; W. Muenzing; E. A. Moser; M. Seiderer

1982-01-01

164

Bone lesion detection with carrier-added 99mTc-EDTMP in comparison with 99mTc-DPD.  

PubMed

An increased uptake of bone-seeking radiopharmaceuticals into malignant bone lesions could further improve the diagnostic accuracy of routine bone scanning. The tracers used in clinical routine for bone scanning are methylene-diphosphonate (MDP), dicarboxypropane-diphosphonate (DPD) and ethylenediaminetetramethylene-phosphonate (EDTMP). MDP and DPD are usually labelled with 99mTc for diagnostic use, whereas EDTMP is labelled with 153Sm for therapeutic purposes. This study aimed to compare, for the first time, bone scanning with an improved preparation of 99mTc-EDTMP (by the addition of rhenium) (carrier-added) with 99mTc-DPD. Twenty malignant bone lesions were investigated in 10 patients. The ratios of bone lesion to soft tissue (BL/ST) and of bone lesion to normal bone (BL/NB) were compared 3 h after the injection of either compound. Quantitative analysis demonstrated a significant (P<0.05) difference in BL/ST ratio in favour of 99mTc-DPD. The BL/NB ratio was not significantly different. Visual image analysis resulted in a clinically comparable interpretation of imaging studies with the use of 99mTc-DPD and carrier-added 99mTc-EDTMP. These preliminary data support the concept of carrier addition to increase bone uptake by the modification of the complex structure of 99mTc-EDTMP. However, any advantage over conventional 99mTc-based tracers for bone scintigraphy in clinical use needs to be demonstrated in controlled trials. PMID:15097810

Fueger, Barbara J; Mitterhauser, Markus; Wadsak, Wolfgang; Ofluoglu, Sedat; Traub, Tatjana; Karanikas, Georgios; Dudczak, Robert; Pirich, Christian

2004-04-01

165

Poor Tc-99m dimercaptosuccinic acid uptake, re-evaluation with Tc-99m MAG3 scintigraphy in Lowe syndrome  

PubMed Central

Tc-99m dimercaptosuccinic acid (DMSA) is filtered through the glomeruli and reabsorbed by the proximal tubules as low molecular weight proteins. In Lowe syndrome this mechanism is impaired and so poor DMSA uptake is seen. Poor DMSA uptake was shown in very few studies, but none mentioned normal Tc-99m MAG3 uptake. In this case, the patient had poor DMSA uptake, normal MAG3 uptake and a neurogenic bladder in anterior to the left kidney that attenuates left kidney.

Koca, Gokhan; Atilgan, Hasan Ikbal; Demirel, Koray; Diri, Akif; Korkmaz, Meliha

2011-01-01

166

Synthesis and properties of 99 Tc(I) and 99 m Tc(I) hexacarbonyl in aqueous solutions  

Microsoft Academic Search

A procedure was developed for preparing Tc(CO)6ClO4 by carbonylation of a solution of technetium(I) tricarbonyltriaqua complex in 2 M HClO4 in a pressure vessel at 100–170°C and CO pressure of 150 atm. The hexacarbonyltechnetium cation in solution was characterized\\u000a by IR and 99Tc NMR spectroscopy, and also by high-performance liquid chromatography (HPLC). The effect of particular acid and of synthesis

A. E. Miroslavov; G. V. Sidorenko; A. A. Lumpov; V. A. Mikhalev; D. N. Suglobov

2009-01-01

167

The rabbit biodistribution of a therapeutic dose of zoledronic acid labeled with Tc99m  

Microsoft Academic Search

The aim of the present study was to label a therapeutic dose of zoledronic acid (ZOL) with Tc-99m, evaluate its in vitro stability and compare its biodistribution to 99mTc-methylene biphosphonate (99mTc-MDP) in normal rabbits. Preparation of 0.50mg of 99mTc-ZOL was carried out by the reduction of 99mTc-pertechnetate in the presence of stannous chloride. The radiolabeling efficiency was found to be

Makbule Asikoglu; Funda Gamze Durak

2009-01-01

168

The Tribolium chitin synthase genes TcCHS1 and TcCHS2 are specialized for synthesis of epidermal cuticle and midgut peritrophic matrix  

Microsoft Academic Search

Functional analysis of the two chitin synthase genes, TcCHS1 and TcCHS2 , in the red flour beetle, Tribolium castaneum , revealed unique and complementary roles for each gene. TcCHS1- specific RNA interference (RNAi) disrupted all three types of moult (larval-larval, larval- pupal and pupal-adult) and greatly reduced whole-body chitin content. Exon-specific RNAi showed that splice variant 8a of TcCHS1 was

Y. Arakane; S. Muthukrishnan; K. J. Kramer; C. A. Specht; Y. Tomoyasu; M. D. Lorenzen; M. Kanost; R. W. Beeman

2005-01-01

169

New radiolabeled CCK8 analogues [Tc99m-GH-CCK8 and Tc99m-DTPA-CCK8]: preparation and biodistribution studies in rats and rabbits  

Microsoft Academic Search

The aim of this study is to label CCK-8 with Tc-99m and to investigate its radiopharmaceutical potential. CCK-8 was labeled with Tc-99m using GH and DTPA as bifunctional chelating agents. Labeling efficiency was higher than 99%. Complex was stable more than 5 hours at room temperature. 37 MBq Tc-99m-GH-CCK-8 or Tc-99m-DTPA-CCK-8 was administered intravenously to rabbits for biodistribution experiments. Dynamic

T Ertay; P Unak; R Bekis; F Yurt; F. Z Biber; H Durak

2001-01-01

170

Preservation of Long-Term Memory and Synaptic Plasticity Despite Short-Term Impairments in the Tc1 Mouse Model of Down Syndrome  

ERIC Educational Resources Information Center

|Down syndrome (DS) is a genetic disorder arising from the presence of a third copy of the human chromosome 21 (Hsa21). Recently, O'Doherty and colleagues in an earlier study generated a new genetic mouse model of DS (Tc1) that carries an almost complete Hsa21. Since DS is the most common genetic cause of mental retardation, we have undertaken a…

Morice, Elise; Andreae, Laura C.; Cooke, Sam F.; Vanes, Lesley; Fisher, Elizabeth M. C.; Tybulewicz, Victor L. J.; Bliss, Timothy V. P.

2008-01-01

171

Power Systems Development Facility Gasification Test Run TC07  

SciTech Connect

This report discusses Test Campaign TC07 of the Kellogg Brown & Root, Inc. (KBR) Transport Reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using a particulate control device (PCD). The Transport Reactor was operated as a pressurized gasifier during TC07. Prior to TC07, the Transport Reactor was modified to allow operations as an oxygen-blown gasifier. Test Run TC07 was started on December 11, 2001, and the sand circulation tests (TC07A) were completed on December 14, 2001. The coal-feed tests (TC07B-D) were started on January 17, 2002 and completed on April 5, 2002. Due to operational difficulties with the reactor, the unit was taken offline several times. The reactor temperature was varied between 1,700 and 1,780 F at pressures from 200 to 240 psig. In TC07, 679 hours of solid circulation and 442 hours of coal feed, 398 hours with PRB coal and 44 hours with coal from the Calumet mine, and 33 hours of coke breeze feed were attained. Reactor operations were problematic due to instrumentation problems in the LMZ resulting in much higher than desired operating temperatures in the reactor. Both reactor and PCD operations were stable and the modifications to the lower part of the gasifier performed well while testing the gasifier with PRB coal feed.

Southern Company Services

2002-04-05

172

Correlation of Tc with Crystal Chemical Parameters in High-Tc Cuprates, Diborides and Borocarbides: Concept of Arrangement and Function of Layered Superconductors  

Microsoft Academic Search

The problems of participation of crystal chemical factors in creating of conditions to occurrence of a superconducting state in layered superconductors are considered. On the basis of the experimental data, given in the literature, new correlations of Tc with relation of crystal chemical parameters in high-Tc cuprates, diborides and borocarbides are established, the critical crystal chemical parameters controlling Tc are

L. M. Volkova; S. A. Polyshchuk; F. E. Herbeck

2004-01-01

173

Iron phosphate glass for immobilization of 99Tc  

NASA Astrophysics Data System (ADS)

Technetium-99 (99Tc) can bring serious environmental threats because of its long half-life (?1/2 = ˜2.1 × 105 years), high fission yield (˜6%), and high solubility and mobility in the ground water. The high volatility makes it difficult to immobilize 99Tc in continuous melters vitrifying 99Tc-containing nuclear wastes in borosilicate glasses. This work explores a possibility of incorporating a high concentration of 99Tc, surrogated by the non-radioactive Re, in an iron phosphate glass by melting mixtures of iron phosphate glass frits with 1.5–6 mass% KReO4 at ˜1000 °C. The retention of Re achieved was ˜1.1 mass%. The normalized Re release by the 7-day Product Consistency Test was <10?2 g/m2. Surprisingly, the Re escaped from the melt within a short time of heating, especially when the temperature was increased. Therefore, 99Tc volatilization would still be a challenging task for its immobilization in iron phosphate glasses.

Xu, Kai; Hrma, Pavel; Um, Wooyong; Heo, Jong

2013-10-01

174

Estimated dTc/dP and dTc/d?ij for the Y1Ba2Cu3O7 superconductor  

NASA Astrophysics Data System (ADS)

For Y1Ba2Cu3O7, we estimated the critical-temperature pressure derivative dTc/dP and the three principal uniaxial compressive-stress derivatives dTc/d?a, dTc/d?b, dTc/d?c. These estimates are useful because the measured values, especially dTc/d?ij, show such strong disagreement. To estimate these thermodynamic quantities, we extended a model of Ohta and coworkers that relates Tc to ?VA, the difference in Madelung energy at the two oxygen sites, apical and planar. We found that dTc/dP is positive, but small: 0.09 K/GPa. For uniaxial-stress, we found that dTc/d?c: 0.09 K/GPa. Thus, uniaxial compression along the c-axis (bringing together the CuO2 planes) produces no remarkable change in Tc. We found a negative dTc/d?b: -0.06 K/GPa. This negative value agrees with results derived by Millis and Rabe, and it agrees with Tc increasing with an increasing b unit-cell dimension. Plane compressive stress in the a-c plane produces the largest effect: 0.17 K/GPa, twice that for hydrostatic compression.

Ledbetter, Hassel; Lei, Ming

1991-06-01

175

Leukocyte labeling with isonitrile complexes of Tc-99m  

SciTech Connect

Leukocyte labelling with Tc-99m may result in a useful method for the detection and localization of active inflammatory processes in patients, particularly in the pediatric population. Previous studies qin this laboratory have shown that hexakis(alkylisonitrile)technetium(I) complexes readily label V79 lung fibroblasts in vitro, and this work is now being extended to isolated human white blood cells (WBC). Two lipophilic water-soluble technetium cations, the t-butyl (Tc-99m(TBI)) and cyclohexyl (Tc-99m(CHI)) analogs, were prepared essentially ligand-free at no-carrier-added levels in aqueous media and introduced in 10% propylene glycol/90% normal saline solution to WBC at room temperature. The cells were isolated from whole blood via sedimentation, centrifugation, and hypotonic hemolysis of the red blood cells. The labeling yield was studied as a function of incubation time (10-45 min), amount of activity (0.35-8.0 mCi), and total WBC (2.5 x 10/sup 7/-1.3 x 10/sup 8/). After 10 min incubation using 10/sup 8/ cells, the initial uptake of Tc-99m(TBI) was 40%, of which 50% remained bound after one saline wash. By contrast, the labeling efficiency with Tc-99m(CHI) was 85%, with 90% of the label still bound after washing. The labeling yield was unrelated to activity levels of incubation time, but was proportional to the number of WBC present. The entire process could be complemented in approximately one hour. The labeling yields with Tc-99m-(CHI) are comparable to those now obtained with the clinically available In-111 oxine.

Van den Abbeele, A.D.; Solorzano, C.; Jones, A.G.; Beardsley, D.S.; Treves, S.; Davison, A.

1985-05-01

176

Radionuclide imaging of myocardial infarction using Tc-99m TBI  

SciTech Connect

The cationic complex Tc-99m t-butylisonitrile (TBI) concentrates in the myocardial tissue of several animal species. Its myocardial distribution is proportional to blood flow both in zones of ischemia and in normal myocardium at rest. Planar, tomographic, and gated myocardial images have been obtained using Tc-99m TBI in the human. The authors investigated the potential application of Tc-99m TBI imaging to detect and localize myocardial infarction. Four subjects without clinical evidence of cardiovascular disease and five patients with ECG evidence of previous myocardial infarction were studied. Tc-99m TBI (10mCi) was injected intravenously with the patient in a resting state with planar imaging in the anterior, 30 and 70 degree LAO projections beginning one hr after injection. The distribution of the tracer was homogeneous throughout the left ventricular wall in the normal subjects. Regional perfusion defects were present in 4/5 of the patients with myocardial infarction. Location of the defects corresponded to the location of the infarct using ECG criteria (2 inferoposterior and 2 anterior). The patient in whom the Tc-99m TBI image appeared normal had sustained a subendocardial myocardial infarct which could not be localized by ECG; the other 4 pts had transmural infarcts. Anterior and 30 degree LAO images were of excellent quality in all cases; there was overlap of the liver on the inferior wall of the left ventricle on the 70 degree LAO views. The authors conclude that accurate perfusion imaging may be possible using Tc-99m TBI in patients with transmural myocardial infarction.

Holman, B.L.; Campbell, S.; Kirshenbaum, J.M.; Lister-James, J.; Jones, A.G.; Davison, A.; Antman, E.

1985-05-01

177

Results of hepatobiliary imaging using Tc-99m EHIDA  

SciTech Connect

Tc-99m labelled 2,6-diethylphenylcarbamoylmethyliminodiacetic acid (EHIDA) is a non-toxic radiopharmaceutical that was found to undergo rapid biliary excretion in a normal human, with accumulation of radioactivity in the gall bladder and intestine. Images in normal subjects and nonjaundiced patients showed rapid concentration of tracer by the liver and the passage of the same into the intestine within 15 to 40 minutes, with or without visualization of the gall bladder. In the jaundiced patient, the tracer blood clearance was delayed and urinary excretion was increased. Tc-99m EHIDA has been extensively investigated in 1634 patients to evaluate its performance in the diagnosis of hepatobiliary disorders.

Ansari, S.M.; Ahmed, R.; Rok

1989-05-01

178

How to optimize high-Tc superconductive cuprates  

NASA Astrophysics Data System (ADS)

Several examples are used here to illustrate the way that modifying the structure of high-Tc superconductive cuprates (HTSCs) allows their superconducting properties to be significantly improved. It is shown that energetic heavy ions can be used as projectiles to modify and tailor superconducting properties. In particular, the creation of columnar defects with dimensions of Xi(ab) or more can act as efficient pinning centers for flux lines and can be used to extend the operating field range of HTSCs to substantially higher fields near Tc's. The crucial role of radiation-induced defects in controlling the magnetic hysteresis shape and therefore the critical current density is demonstrated.

Raveau, B.; Michel, C.; Hervieu, M.; Groult, D.; Maignan, A.; Provost, J.

1992-06-01

179

Experimental investigations of the isotope effect in high Tc superconductors  

NASA Astrophysics Data System (ADS)

We present data on the copper isotope effect ?Cu = - ln Tc/? ln mCu for oxygen depleted YBa2Cu3O7-? as function of ?. ?Cu is negative for all ?. In the 60 K plateau, ?Cu reaches values of -0.14 or -0.34 for two comparison pairs. Outside the 60 K plateau, ?Cu increases in absolute value. Similarities with results on dTc/dP in this system suggest that ?Cu is related to mass-dependent ordering in the chain system.

Franck, J. P.

1996-01-01

180

Dynamic Observation of Vortices in HIGH-Tc Superconductors  

NASA Astrophysics Data System (ADS)

Quantized magnetic vortices inside high-Tc superconductors were observed using the phase shift of electron waves passing through the vortex magnetic fields with our recently developed 1-MV field-emission electron microscope, which has the brightest electron beam yet attained. We were able to investigate the microscopic pinning mechanism of columnar defects, which are produced by irradiation of high-energy [heavy ions] and are regarded as one of the most effective pinning centers in high-Tc superconnductors. In particular, we determined under which conditions individual vortex lines are trapped along tilted columnar defects in Bi-2212 thin films, which results in a strong pinning effect.

Tonomura, Akira

2002-10-01

181

Role of additional mutations outside the YMDD motif of hepatitis B virus polymerase in L(-)SddC (3TC) resistance.  

PubMed

L(-)SddC (3TC) has been shown to be the most promising nucleoside analogue used for the treatment of hepatitis B virus (HBV) infection. Unfortunately, it has been reported that about 12% of HBV-infected patients experience a recurrence of HBV after a period of treatment with 3TC. Point mutations were detected in the HBV polymerase of those viruses from 3TC-resistant patients. A common mutation occurred at methionine in the YMDD motif. In this report, we present mutants that were generated from the HBV genome (adr subtype) by site-directed mutagenesis based on clinical reports from other investigators. With the transient transfection system, it was found that by changing methionine to valine or isoleucine at the YMDD motif, the viral DNA replication would be more than 100-fold less efficient than that of the wild-type virus. Some additional mutations outside the YMDD motif could enhance the replication of the virus containing a YMDD mutation. Various levels of resistance to 3TC were observed in HBV mutants containing point mutations both inside and outside the YMDD motif. These results suggest that the mutations outside the YMDD motif compensate the YMDD mutation to some extent for the viral replication and may also contribute to clinical viral resistance to 3TC. PMID:9633992

Fu, L; Cheng, Y C

1998-05-15

182

Immunization of protein HPV16 E7 in fusion with mouse HSP70 inhibits the growth of TC-1 cells in tumor bearing mice.  

PubMed

Human papillomavirus (HPV) 16 is the primary etiologic agent of cervical cancer. Most HPV16 therapeutic vaccines target E7 protein which is consistently expressed in tumor cells. In this study, we cloned mouse autologous heat shock protein 70 (mHSP70) gene from mouse liver cells and then expressed mHSP70 and fused HPV16 E7-mHSP70 (E7 at the N-terminus and mHSP70 at the C-terminus) proteins in E. coli. Then we investigated the inhibition of TC-1 cell growth by using the E7-expressing murine tumor cell line, TC-1, as a model of cervical cancer. In this model, mice were immunized with the fusion protein of E7-mHSP70 without any adjuvant. The results showed that prophylactic immunization of E7-mHSP70 protected mice against challenge with TC-1 cells. In addition, therapeutic immunization with E7-mHSP70 could inhibit TC-1 tumor growth on lungs. Our study demonstrated that immunization with E7-mHSP70 protein without any adjuvant could generate anti-tumor effect in mice challenged with TC-1 cells. PMID:21722685

Li, Yan-Li; Liu, Jie; Liu, Jian-Ning; Zhang, Jing

2011-06-29

183

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides.  

PubMed

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (Mössbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). Mössbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O. PMID:18754467

Peretyazhko, T; Zachara, J M; Heald, S M; Kukkadapu, R K; Liu, C; Plymale, A E; Resch, C T

2008-08-01

184

COLAS Program Generator and Program Generator Generator.  

National Technical Information Service (NTIS)

The manual describes the use of two tools for the development of software: the COLAS Program Generator (CPG), which generates the complete control part of programs for interactive use from a specification of the user interaction. In addition the specifica...

J. J. P. van Hulzen

1988-01-01

185

Mechanochemical effects on high-Tc superconductor powders.  

National Technical Information Service (NTIS)

We have investigated the mechanochemical effects on high-Tc superconductor (YBa(sub 2)Cu(sub 3)O(sub 7)-(delta)) powders. The powder was mechanically ground in air using an agate mortar with a pestle. The grinding time was varied from 2 to 100 min. The me...

T. Yamada R. Nagai M. Takeuchi E. Minehara

1991-01-01

186

Power Systems Development Facility Gasification Test Run TC09  

SciTech Connect

This report discusses Test Campaign TC09 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier during TC09 in air- and oxygen-blown modes. Test Run TC09 was started on September 3, 2002, and completed on September 26, 2002. Both gasifier and PCD operations were stable during the test run, with a stable baseline pressure drop. The oxygen feed supply system worked well and the transition from air to oxygen was smooth. The gasifier temperature varied between 1,725 and 1,825 F at pressures from 125 to 270 psig. The gasifier operates at lower pressure during oxygen-blown mode due to the supply pressure of the oxygen system. In TC09, 414 hours of solid circulation and over 300 hours of coal feed were attained with almost 80 hours of pure oxygen feed.

Southern Company Services

2002-09-30

187

Amyloid goiter: preoperative scintigraphic diagnosis using Tc-99m pyrophosphate  

SciTech Connect

Amyloid goiter is a rare clinical entity. The diagnosis is rarely made preoperatively because clinical and laboratory findings are nonspecific. The authors report two cases of amyloid goiter in whom the diagnosis was made preoperatively using Tc-99m pyrophosphate scintigraphy.

Lee, V.W.; Rubinow, A.; Pehrson, J.; Skinner, M.; Cohen, A.S.

1984-04-01

188

Progress in high Tc magnetic sensors and their applications  

Microsoft Academic Search

We report recent progress on the development of components needed for high Tc SQUID magnetic sensors, and on some of the early applications which are appearing or can be foreseen. The SNS type edge junction, and the step edge and biepitaxial grain boundary junction technologies are considered and we include details of our own YBCO device based on steps which

G B Donaldson; R M Bowman; A Cochran; K J Kirk; C M Pegrum; J C Macfarlane

1992-01-01

189

Asteroid 2008 TC3: A Review and a Look Forward  

NASA Astrophysics Data System (ADS)

On October 6, 2008, a small 4-m sized asteroid called 2008 TC3 was discovered in space and tracked to an impact location in northern Sudan. 600 meteorites were recovered. We will review the latest data and discuss opportunities for future studies.

Jenniskens, P.; Shaddad, M. H.; Almahata Sitta Consortium

2012-05-01

190

Subgap Structures in High-Tc Intrinsic Josephson Junctions  

Microsoft Academic Search

Due to their extremely short coherence length many high-Tc superconductors form natural superconducting multilayers. Adjacent superconducting layers are weakly coupled by the Josephson effect. As a result single crystals act intrinsically as vertical stacks of hundreds of Josephson junctions. We start by summarizing our present state of knowledge, including recent observations of Cherenkov radiation from moving fluxons (G. Hechtfischer, R.

Paul Müller

1998-01-01

191

Glycopyrrolate in \\/sup 99m\\/Tc-pertechnetate brain imaging  

Microsoft Academic Search

Glycopyrrolate, a synthetic anticholinergic agent, was administered ; parenterally to two groups of patients referred for \\/sup 99m\\/Tc-pertechnetate ; brain imaging to assess its ability to suppress pertechnetate uptake by the ; choroid plexus, oral mucosa, and salivary (parotid) glands. Pertechnetate ; activity was almost completely eliminated from the choroid plexus and mouth and ; appeared to be moderately reduced

R. A. Holmes; C. N. Luth

1975-01-01

192

High Tc SQUID system and magnetic marker for biological immunoassays  

Microsoft Academic Search

High Tc SQUID system is developed for the detection of the biological binding-reaction between antigen and its antibody. In this measurement, the antibody is labeled with magnetic nanoparticles, and the magnetic signal from the nanoparticles is measured. The excitation field of a few mT is applied in parallel to the SQUID in order to magnetize the nanoparticles. Due to mechanical

K. Enpuku; D. Kuroda; T. Q. Yang; K. Yoshinaga

2003-01-01

193

Research Activities on HIGH-Tc Superconductors in Japan  

NASA Astrophysics Data System (ADS)

Newly discovered high-Tc superconductor, Bi-Sr-Ca-Cu-O (BSCCO) systems are intensively investigated in Japan. Most works are experimental, but not theoretical. Some recent papers on (1) crystal structure, (2) impurity substitution effects and (3) thin film fabrication technologies are briefly reviewed.

Sugawara, K.

194

Mathematics and Science: Female Students and LEGO TC Logo.  

ERIC Educational Resources Information Center

Describes a three-week workshop involving 20 teachers and 40 female students, grades 3 through 8, who worked in small groups to use the LEGO TC logo program, an approach that integrates mathematics and science instruction. Discussion includes the impact of single-sex, small group work on student attitudes toward mathematics and science. (six…

Hutchinson, Elaine J.; Whalen, Mary T.

1995-01-01

195

Comparison of the effect of 99mTc-DPD and 99mTc-MDP on experimentally-induced osteoarthritis in the stifle joint of the dog.  

PubMed

This study was designed to evaluate the effect of 99mTechnetium-dicarboxypropane diphosphonate (99mTc-DPD) and 99mTechnetium-methylene diphosphonate (99mTc-MDP) on bone scan image quality and time in dogs with osteoarthritis. The left cranial cruciate ligament (CrCL) in ten healthy adult Beagle dogs was transected under general anesthesia. The dogs were assigned to 99mTc-DPD-injected or 99mTc-MDP-injected groups. Stifle joint scintigraphy was performed after intravenous injection of 10 mCi 99mTc-DPD or 99mTe-MDP. Scintigraphy was conducted before CrCL transection and 2, 4, 6, 8, 10 and 12 weeks after the procedure. There were no significant differences in density, sensitivity and pathological foci between the 99mTc-DPD and 99mTc-MDP groups of experimentally-transected CrCL dogs. A comparison of the images obtained with Pinhole type and low energy general purpose type collimators of the stifle joint of normal dogs and after CrCL transaction revealed no significant differences in bone radioactivity. Scintigraphs were obtained 3 h after 99mTc-MDP and 2 h after 99mTc-DPD injection. In conclusion, application of 99mTc-DPD and 99mTc-MDP in experimentally-induced osteoarthritis of the stifle joint in dogs results in similar effects on radioactive uptake ratio and image quality. 99mTc-DPD is more efficient than 99mTc-MDP in reducing the overall time of scintigraphy. PMID:15999549

Lee, Jae Yeong; Lee, Won Guk; Kim, Joong-Hyun; Kang, Seong Soo; Bae, Chun Sik; Koong, Sung-Soo; Choi, Seok Hwa

196

Operation of high-Tc SFQ devices at near liquid nitrogen temperature  

NASA Astrophysics Data System (ADS)

As the operating temperature of the SFQ logic circuits gets higher by using high-Tc, superconductors, the effect of noise on switching a Josephson junction to the voltage state becomes more important. In this paper, we report our work on high-Tc SFQ RS flip-flop which was made with YBCO thin film deposited on a SrTiO3, bi-crystal. The circuit operated correctly at 71 K over the 200 computer-generated clock cycles without making errors, where a reset or a set operation was made over one clock cycle. Good agreement between the measured data and the calculation based on the thermal activation theory was obtained. The effective noise temperature used to fit the data was much higher than the physical temperature. This could be due to the instrument noise. improvement in the measurement set-up might reduce the effective noise temperature. Also our measurement results indicate that the elevation of the operating temperature near the liquid nitrogen temperature may not affect the margin of the circuit.

Kim, Y. H.; Lee, J. M.; Hahn, T. S.; Choi, S. S.; Kang, J. H.; Park, S. J.

1997-02-01

197

Tc and Re Behavior in Borosilicate Waste Glass Vapor HydrationTests  

SciTech Connect

Technetium (Tc), found in nuclear waste, is of particularconcern with regard to long-term waste storage because of its longhalf-life and high mobility in the environment. One method ofstabilization of such waste is through vitrification to produce a durableborosilicate glass matrix. The fate of Tc under hydrothermal conditionsin the Vapor Hydration Test (VHT) was studied to assess and possiblypredict the long-term rate of release of Tc from borosilicate wasteglass. For comparison, the fate of rhenium (Re), the preferrednon-radioactive surrogate for Tc, was similarly studied. X-ray absorptionspectroscopy (XAS) and scanning electron microscopy (SEM) measurementswere made on each original borosilicate glass and the correspondingsample after the VHT. Tc K-edge XAS indicates that, despite starting withdifferent Tc(IV) and Tc(VII) distributions in each glass, bothcorresponding VHT samples contain 100 percent Tc(IV). The Tc reductionwithin the VHT samples may be driven by simultaneous oxygen depletionfrom corrosion of the surrounding stainless steel vessel. From SEManalyses, both of the Tc-containing VHT samples show complete alterationof the original glass, significant Tc enrichment near the sample surface,and nearly complete depletion of Tc toward the sample center. XASindicates Tc(IV)O6 octahedra, possibly within gel-like amorphoussilicates in both VHT samples, where Tc-Tc correlations are observed inthe higher Tc-content VHT sample. Re LII-edge XAS and SEM indicate quitedifferent behavior for Re under VHT conditions. Re oxidation stateappears to be invariant with respect to the VHT treatment, whereperrhenate (Re(VII)) species are dominant in all Re-containing samplesinvestigated; Re2O7 concentrations are low NEAR the sample surface andincrease to approach the concentration of the un-reacted glass toward thesample center.

McKeown, David A.; Buechele, Andrew C.; Lukens, Wayne W.; Shuh,David K.; Pegg, Ian L.

2006-11-01

198

Emergence of HBV resistance to lamivudine (3TC) in HIV/HBV co-infected patients in The Gambia, West Africa  

PubMed Central

Background Lamivudine (3TC) is a potent inhibitor of both Hepatitis B virus (HBV) and Human Immunodeficiency Virus (HIV) replication and is part of first-line highly active antiretroviral therapy (HAART) in the Gambia. Unfortunately, the effectiveness of 3TC against HBV is limited by the emergence of resistant strains. Aim The aim of this retrospective study was to characterise 3TC-resistant mutations in HBV from co-infected patients receiving HAART, by generating HBV polymerase sequence data and viral loads from HBV genotype E infected patients, both at initiation and during a course of 3TC therapy. Method Samples from 21 HBV chronic carriers co-infected with HIV-1 (n = 18), HIV-2 (n = 2) and HIV-dual (n = 1) receiving HAART for a period of 6-52 months were analysed for the emergence of 3TC-resistance mutations. Findings Sixteen out of 21 HBV/HIV co-infected patients responded well to HAART treatment maintaining suppression of HBV viraemia to low (? 104 copies/mL) (n = 5) or undetectable levels (< 260 copies/ml) (n = 11). Out of the 5 non-responders, 3 had developed 3TC-resistant HBV strains showing mutations in the YMDD motif at position 204 of the RT domain of the HBV polymerase. One patient showed the M204V+ L180M+ V173L+ triple mutation associated with a vaccine escape phenotype, which could be of public health concern in a country with a national HBV vaccination programme. All except one patient was infected with HBV genotype E. Conclusions Our findings confirm the risk of 3TC mutations in HAART patients following monotherapy. This is a novel study on 3TC resistance in HBV genotype E patients and encourage the use of tenofovir (in association with 3TC), which has not shown unequivocally documented HBV resistance to date, as part of first-line therapy in HIV/HBV co-infected patients in West Africa. HBV- hepatitis B infection; HIV- human immunodeficiency virus; HAART- antiretroviral therapy.

2011-01-01

199

Drug-induced modulation of Tc-99m pyrophosphate tissue distribution: what is involved  

SciTech Connect

More than ten years after their introduction, Tc-99m-labeled phosphates and phosphonates (TcP) continue to be of interest to the investigator and to hold promise for new clinical applications in the future. Initially, TcP compounds were valued because of their bone-seeking properties. Emphasis shifted from bone to soft tissue when Bonte et al. introduced Tc-99m-labeled pyrophosphate (TcPPi) for myocardial infarct scanning. Detailed information about TcPPi uptake in ischemic and necrotic myocardial tissue at the subcellular level has accumulated. Therefore, understanding of the mechanism of TcPPi uptake in infarcted myocardium is more detailed than understanding of uptake by bone. A new, and potentially powerful, approach to the use of TcP is being proposed by Carr et al. The authors attempt to modulate favorably the tissue distribution of TcPPi by prior administration of drugs in pharmacological quantities. The authors demonstrate that uptake of TcPPi can be enhanced in the necrotic myocardium, uptake by bone can be reduced, and the lesion-to-blood ratio can be altered favorably when vitamin D/sub 3/ or desoxycorticosterone acetate (DOCA) is administered in pharmacological doses before the TcPPi injection. A short review is presented of background information helpful for interpreting the drug effects on TcPPi uptake in bone or necrotic myocardial tissue.

Wahner, H.W.; Dewanjee, M.K.

1981-06-01

200

Leaching TC99 from DWPF glass in simulated geologic repository groundwaters  

Microsoft Academic Search

The purpose was to determine if DWPF glass in geologic groundwaters would immobilize Tc-99 as well as it does other elements. A previous study (using a borosilicate glass of a very different composition from DWPF glass) indicated that Tc-99 leached rapidly from the glass suggesting that glass may not be a good matrix for immobilizing Tc-99. It was suggested that

N. E. Bibler; A. R. Jurgensen

1986-01-01

201

Binding of ciprofloxacin labelled with technetium Tc 99m versus 99mTc-pertechnetate to a live and killed equine isolate of Escherichia coli  

PubMed Central

Abstract This paper describes a simple methodology for evaluating the bacterial binding of ciprofloxacin labelled with technetium Tc 99m. Using this methodology, the binding of 99mTc-ciprofloxacin by live Escherichia coli was compared with the binding of 99mTc-ciprofloxacin by killed E. coli and the binding of 99mTc-pertechnetate (99mTcO4 ?) by live E. coli. The antimicrobial effect of 99mTc-ciprofloxacin on E. coli was evaluated. Four groups were defined: live E. coli with 99mTc-ciprofloxacin, live E. coli with 99mTcO4 ?, killed E. coli with 99mTc-ciprofloxacin, and killed E. coli with 99mTcO4 ?. After 0, 2, and 4 h of incubation of 1 × 108 colony-forming units of E. coli suspended in 5 mL of sterile distilled water with 1.85 MBq of 99mTc-ciprofloxacin or 99mTcO4 ?, 1 mL from each sample was centrifuged. The radioactivity of the bacterial pellet and that of the supernatant were measured separately, and the percentage of sample radioactivity attributable to bacterial binding was calculated. Of the 99mTc-ciprofloxacin, 3.6% to 5.9% was bound to live or killed E. coli; only 0.1% to 0.2% of the 99mTcO4 ? was bound to live E. coli (P < 0.0001). No significant difference in 99mTc-ciprofloxacin binding was found between live and killed E. coli (P = 0.887). An antimicrobial effect on E. coli was seen with 99mTc-ciprofloxacin: colony counts were reduced after 4 h. The small amount of 99mTc-ciprofloxacin binding and the lack of difference in binding between live and killed E. coli may limit the utility of this methodology in evaluating the presence of E. coli infection.

2005-01-01

202

Electrical generation  

NSDL National Science Digital Library

How is electricity generated? This reading, part of a series about the future of energy, introduces students to the production of electricity using a generator. Students read about the movement of electrons called current electricity. Static electricity is also discussed. Students follow as the generation of electric current is described using magnets in a generator. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2004-01-01

203

Correlation of Tc with Crystal Chemical Parameters in High-Tc Cuprates, Diborides and Borocarbides: Concept of Arrangement and Function of Layered Superconductors  

Microsoft Academic Search

The problems of participation of crystal chemical factors in creating of\\u000aconditions to occurrence of a superconducting state in layered superconductors\\u000aare considered. On the basis of the experimental data, given in the literature,\\u000anew correlations of Tc with relation of crystal chemical parameters in high-Tc\\u000acuprates, diborides and borocarbides are established, the critical crystal\\u000achemical parameters controlling Tc are

L. M. Volkova; S. A. Polyshchuk; F. E. Herbeck

2004-01-01

204

Biochemical studies of the renal radiopharmaceutical compound dimercaptosuccinate. IV. Interaction of 99m Tc-DMS and 99 Tc-DMS complexes with blood serum proteins  

Microsoft Academic Search

As a crucial step towards understanding the mechanism of localisation of radiopharmaceuticals in specific target organs, the interaction of the radiopharmaceuticals 99mTc-DMS and 99Tc-DMS with blood serum proteins was studied. The interaction of 99mTc-DMS radiopharmaceutical was examined from two aspects: total protein binding as well as specificity of binding to certain classes of proteins.

Nada Vanli?-Razumeni?; Jelena Petrovic; Daroslava Gorkic

1984-01-01

205

The production of patient dose level 99mTc medical radioisotope using laser-driven proton beams  

NASA Astrophysics Data System (ADS)

The medical isotope 99mTc (technetium) is used in over 30 million nuclear medical procedures annually, accounting for over 80% of the worldwide medical isotope usage. Its supply is critical to the medical community and a worldwide shortage is expected within the next few decades as current fission reactors used for its generation reach their end of life. The cost of build and operation of replacement reactors is high and as such, alternative production mechanisms are of high interest. Laser-accelerated proton beams have been widely discussed as being able to produce Positron Emission Tomography (PET) isotopes once laser architecture evolved to high repetition rates and energies. Recent experimental results performed on the Vulcan Laser Facility in the production of 99mTc through 100Mo (p,2n) 99mTc demonstrate the ability to produce this critical isotope at the scales required for patient doses using diode pumped laser architecture currently under construction. The production technique, laser and target requirements are discussed alongside a timeline and cost for a prototype production facility.

Clarke, R.; Dorkings, S.; Neely, D.; Musgrave, I.

2013-05-01

206

Poor renal uptake of Tc-99m DMSA and Tc-99m MDP in a patient with Fanconi syndrome and near normal glomerular filtration rate.  

PubMed

The authors present a patient with Fanconi syndrome who demonstrated poor renal uptake of Tc-99m DMSA and high urinary concentration of the tracer. Tc-99m DTPA imaging was normal and the creatinine clearance was only minimally decreased. These findings suggest that Tc-99m DMSA may be accumulated in the kidney by glomerular filtration and subsequent tubular reabsorption. A Tc-99m MDP bone scan showed faint renal uptake, as well as diffuse high skeletal uptake, particularly in the spine, demonstrating that the metabolic bone disease associated with Fanconi syndrome can be one of the causes of poor renal visualization on a bone scan. PMID:7750213

Kim, S E; Cho, J T; Lee, D S; Chung, J K; Kim, S; Lee, M C; Lee, J S; Koh, C S

1995-03-01

207

Can Tc 99m DTPA be Used in Adult Patients in Evaluation of Relative Renal Function Measurement as the Reference Tc 99m DMSA Method?  

PubMed

Objective: In the literature, there are many reports comparing relative renal function calculated with Tc 99m DTPA and Tc 99m DMSA in adults and children. However, there is no consensus about the results. As there is indeterminacy in the reliability of Tc 99m DTPA for the calculation of the relative renal functions, we retrospectively designed a study to compare the relative renal functions measured with Tc 99m DMSA and Tc 99m DTPA in adult patients with renal diseases Material and Methods: We retrospectively analyzed the data of 144 patients who applied to Nuclear Medicine Department of three hospitals between 2009 and 2010 and who had both dynamic and static renal imaging. Renal dynamic scintigraphies were compared to the relative function measured using Tc 99m DMSA static scintigraphy. Comparison of relative renal function measurements using dynamic and static renal scintigraphies was performed using Pearson correlation test. The comparison results were expressed with Bland-Altman analysis. Results: The study was conducted with 144 patients and 288 kidneys. Fifty six of patients were male. Mean age was 39.9±15.2 years. Thirty four patients had hydronephrosis, 28 pyelonephritis, 53 renal calculi, 3 chronic renal failure, 2 acute renal failure, 1 benign renal neoplasia, 15 renal atrophy, 8 ureteropelvic junction stenosis. Relative renal function was calculated in Tc 99m DMSA and 99m Tc-DTPA studies. The mean relative renal functions measured with Tc 99m DTPA was 52.54±23.09% and 47.25±23.09, with Tc 99m DMSA 52.85±21.80% and 47.07±21.77% for right and left kidneys, respectively. In bivariate correlation analysis (Pearson) a significant positive correlation was found between the relative renal functions calculated with Tc 99m DTPA and Tc 99m DMSA (r =0.937, p< 0.001). In Bland-Altman plots, the mean difference between two methods was 0.3 and the correlation limits were between 16.2 to -15.5. Conclusion: As a result, we concluded that Tc 99m DTPA is also a good method for the relative renal function evaluation when compared to Tc 99m DMSA scan. Although Tc 99m DMSA is the most reliable method for the calculation of relative renal function, Tc 99m DTPA can be another choice for the calculation of relative renal function without a complementary DMSA scan particularly in patients who require renogram curve and GFR calculations. Conflict of interest:None declared. PMID:23486843

Yalē?n, Hülya; Ozen, Aynur; Günay, Emel Ceylan; Ozaslan, Inci Aliē; Ozer, Cahit

2011-04-01

208

Can Tc 99m DTPA be Used in Adult Patients in Evaluation of Relative Renal Function Measurement as the Reference Tc 99m DMSA Method?  

PubMed Central

Objective: In the literature, there are many reports comparing relative renal function calculated with Tc 99m DTPA and Tc 99m DMSA in adults and children. However, there is no consensus about the results. As there is indeterminacy in the reliability of Tc 99m DTPA for the calculation of the relative renal functions, we retrospectively designed a study to compare the relative renal functions measured with Tc 99m DMSA and Tc 99m DTPA in adult patients with renal diseases Material and Methods: We retrospectively analyzed the data of 144 patients who applied to Nuclear Medicine Department of three hospitals between 2009 and 2010 and who had both dynamic and static renal imaging. Renal dynamic scintigraphies were compared to the relative function measured using Tc 99m DMSA static scintigraphy. Comparison of relative renal function measurements using dynamic and static renal scintigraphies was performed using Pearson correlation test. The comparison results were expressed with Bland-Altman analysis. Results: The study was conducted with 144 patients and 288 kidneys. Fifty six of patients were male. Mean age was 39.9±15.2 years. Thirty four patients had hydronephrosis, 28 pyelonephritis, 53 renal calculi, 3 chronic renal failure, 2 acute renal failure, 1 benign renal neoplasia, 15 renal atrophy, 8 ureteropelvic junction stenosis. Relative renal function was calculated in Tc 99m DMSA and 99m Tc-DTPA studies. The mean relative renal functions measured with Tc 99m DTPA was 52.54±23.09% and 47.25±23.09, with Tc 99m DMSA 52.85±21.80% and 47.07±21.77% for right and left kidneys, respectively. In bivariate correlation analysis (Pearson) a significant positive correlation was found between the relative renal functions calculated with Tc 99m DTPA and Tc 99m DMSA (r =0.937, p< 0.001). In Bland-Altman plots, the mean difference between two methods was 0.3 and the correlation limits were between 16.2 to -15.5. Conclusion: As a result, we concluded that Tc 99m DTPA is also a good method for the relative renal function evaluation when compared to Tc 99m DMSA scan. Although Tc 99m DMSA is the most reliable method for the calculation of relative renal function, Tc 99m DTPA can be another choice for the calculation of relative renal function without a complementary DMSA scan particularly in patients who require renogram curve and GFR calculations. Conflict of interest:None declared.

Yalc?n, Hulya; Ozen, Aynur; Gunay, Emel Ceylan; Ozaslan, Inci Alic; Ozer, Cahit

2011-01-01

209

Pressure Dependence of Tc for HIGH-Tc Cl-CONTEINED Superconductor (Sr,Ca)3Cu2O4+?Cl2-y  

NASA Astrophysics Data System (ADS)

Chlorine-containing (Sr,Ca)3Cu2O4+?Cl2-y (0212-Cl) superconductor is the high-Tc Cu-oxide superconductor (HTSC) with Tc=80 K and was synthesized under high-pressure and high-temperature. The 0212-Cl has double [CuO2] planes and the apical oxygen are replaced by Chlorine. We measured the resistance of 0212-Cl under high pressure using a diamond-anvil cell up to 13.3 GPa and two-terminal ac-method to investigate the pressure dependence of Tc. Tc of 0212-Cl increases gently with increasing pressure.

Nishiyama, M.; Shimizu, K.; Liu, Q. Q.; Jin, C. Q.

210

Tc-99m radioaerosol clearance as an index of pulmonary epithelial permeability  

SciTech Connect

This investigation examines radiopharmaceutical clearance as an index of alveolar-capillary membrane permeability and as an indicator of disease. Specific objectives include: evaluation of radiopharmaceutical chemical purity following aerosolization, investigation of a chemically related family of compounds to develop new radiopharmaceuticals with improved chemical properties, determination of reproducibility of the radiopharmaceutical clearance technique and the evaluation of the sensitivity of aerosolized solute clearance as an indicator of lung injury. The integrity of the radiopharmaceutical was examined prior to and following aerosol generation. The in vivo pharmacokinetics of a family of aerosolized solutes was evaluated in the beagle dog. The reproducibility of the biological response to radiopharmaceutical deposition was evaluated using dynamic functional imaging in humans and in the beagle. The sensitivity of the technique was evaluated using Tc-99m DTPA and an animal model for lung injury.

Waldman, D.L.

1988-01-01

211

Comparative quality control of some bone-seeking 99m Tc radiopharmaceuticals by gel chromatography  

Microsoft Academic Search

The radiochemical purity of the three osteopatic ligands:99mTc(Sn)-PyP,99mTc(Sn)-DPD and99mTc(Sn)-MDP has been determined by gel chromatography on Sephadex. The results of the analyses strongly depend on the composition of the eluent. The dilution effect of pure saline as eluent was observed in all the preparations examined. The most sensitive was found to be99mTc(Sn)-PyP. The retention of99mTc activity bound to the gel

J. L. Vu?ina

1995-01-01

212

Synthesis, biodistribution and evaluation of 99m Tc-sitafloxacin kit: a novel infection imaging agent  

Microsoft Academic Search

Radiosynthesis of 99mTc-sitafloxacin (99mTc-STF) complex and its efficacy as a potential infection imaging agent was evaluated. Effect of sitafloxacin (STF) concentration,\\u000a sodium pertechnetate (Na99mTcO4), stannous chloride dihydrate (SnCl2·2H2O), and pH on the % radiochemical purity yield (RCP) of 99mTc-STF complex was studied. A stable 99mTc-STF complex up to 120 min with maximum %RCP yield was observed by mixing 2 mg of STF

S. S. Qaiser; A. U. Khan; M. R. Khan

2010-01-01

213

Preparation and evaluation of 99mTc-cefuroxime, a potential infection specific imaging agent: a reliable thin layer chromatographic system to delineate impurities from the 99mTc-antibiotic.  

PubMed

Technetium-99m labelled cefuroxime, a second-generation cephalosporin antibiotic and potential bacteria specific infection imaging agent was evaluated. A good radiochemical purity (95%) of the labelled product was obtained after filtering the reaction mixture through a 0.22 ?m filter. Scintigraphy study of the purified product showed uptake in infectious lesions 45 min after injection and abscess-to-muscle ratios were found to be 1.80, 1.85 and 1.88 at 45 min, 1.5 hr and 3 hr, respectively. A versatile and reliable chromatographic technique to assess the radiochemical purity of (99m)Tc-cefuroxime has also been described. PMID:22871442

Chattopadhyay, Sankha; Ghosh, Mayuri; Sett, Sucharita; Das, Malay Kanti; Chandra, Susmita; De, Kakali; Mishra, Mridula; Sinha, Samarendu; Ranjan Sarkar, Bharat; Ganguly, Shantanu

2012-06-16

214

Decay study of {sup 114}Tc with a Penning trap  

SciTech Connect

The level structure of {sup 114}Ru has been investigated via the {beta} decay of very neutron-rich {sup 114}Tc by means of Penning-trap-assisted {gamma} spectroscopy. The deduced {beta}-decay scheme suggests the existence of two {beta}-decaying states in {sup 114}Tc with I{sup {pi}}=1{sup +} and I{>=} 4, with half-lives of t{sub 1/2}(1{sup +})=90(20) ms and t{sub 1/2}(I{>=}4)=100(20) ms, respectively. The Q{sub {beta}} value, which covers a possible mixture of two states, has been determined to be Q{sub {beta}}=11 785(12) keV. The level energies in {sup 114}Ru are compared with theory by using a microscopic Bohr Hamiltonian approach with the Sly4 version of the Skyrme interaction.

Rissanen, J.; Elomaa, V.-V.; Eronen, T.; Hakala, J.; Jokinen, A.; Moore, I. D.; Karvonen, P.; Penttilae, H.; Rahaman, S.; Reponen, M.; Saastamoinen, A.; Weber, C.; Aeystoe, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FI-40014 Jyvaeskylae (Finland); Kurpeta, J.; Plochocki, A. [Faculty of Physics, University of Warsaw, ul. Hoza 69, 00-681 Warsaw (Poland); Prochniak, L. [Institute of Physics, Maria Curie-Sklodowska University, pl. Maria Curie-Sklodowskiej 1, 20-031 Lublin (Poland); Szerypo, J. [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Am Coulombwall 1, D-85748 Garching (Germany); Urban, W. [Faculty of Physics, University of Warsaw, ul. Hoza 69, 00-681 Warsaw (Poland); Institut Laue-Langevin, 6 rue J. Horowitz, F-38042 Grenoble (France)

2011-01-15

215

Identification of pseudospin partner bands in {sup 108}Tc  

SciTech Connect

High-spin structures in the neutron-rich {sup 108}Tc nucleus have been reinvestigated by measuring the prompt {gamma}-rays from spontaneous fission of {sup 252}Cf. A previously known collective band has been extended up to higher spin states and a new side band has been identified. These doublet bands are proposed as pseudospin partner bands with configurations {pi}1/2{sup +}[431] x {nu}[312{approx}5/2{sup +},3/2{sup +}], which is a first identification in A{approx}100 region. The particle-rotor model (PRM) was applied to calculate levels and B(M1)/B(E2) ratios of the bands in {sup 108}Tc. The calculated results are in good agreement with the experimental values.

Xu, Q.; Wang, J. G.; Ding, H. B.; Gu, L.; Yeoh, E. Y. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhu, S. J. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Liu, S. H.; Li, K. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Qi, B.; Meng, J. [School of Physics, Peking University, Beijing 100871 (China); Peng, J. [Department of Physics, Beijing Normal University, Beijing 100875 (China); Luo, Y. X. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ma, W. C. [Department of Physics, Mississippi State University, Mississippi State, Mississippi 39762 (United States)

2008-12-15

216

Pharmacokinetics of intravenously injected Tc-99m labeled ferrite nanobeads  

NASA Astrophysics Data System (ADS)

We study the time varying biodistribution of ferrite (Fe3O4) nanoparticles upon in vivo injection. For this purpose, a novel process of directly labeling radioactive Tc-99m with ferrite nanoparticles was developed. The radiobeads serve as a tracer to provide information on the uptake of injected particles by organs. In the course of our study, Tc-99m labeled ferrite beads were intravenously injected into the tail vein of rats. The time course of changes in the radio-intensity of heart, lung, and liver could be achieved by real-time scintigraphic images. It was observed that the particle uptake by organs is very fast and completed within the first few minutes after intravenous injection. The pharmacokinetic behavior of the radiobead uptake was quantitatively described by a two-compartment model.

Fu, Chao-Ming; Wang, Yuh-Feng; Guo, Yu-Feng; Wang, Li-Shin; Chuang, May-Haw; Cham, Thau-Ming

2009-04-01

217

Novel estradiol based metal complexes of Tc-99m.  

PubMed

Aiming to contribute to the design of technetium imaging agents for estrogen receptor (ER) positive breast tumors, we have synthesized and evaluated the novel organometallic estradiol complexes (fac-[M(CO)(3)(?(3)-10)](+) and fac-[M(CO)(3)(?(3)-12) M=Re/(99m)Tc) using two different bifunctional tridentate ligands (4 and 8). The rhenium complexes (13 and 14) were fully characterized by IR, (1)H NMR, (13)C NMR, mass spectrometry and elemental analyses. The (99m)Tc complexes (15 and 16) were obtained with high radiochemical purity and exhibited high in vitro radiochemical stability. To get a first insight into the relevance of these complexes for targeting ER positive tumors, ER binding affinity assays and cellular internalization studies in an ER expressing cell line, MCF-7, have also been performed suggesting a non ER mediated uptake. PMID:22469776

Neto, Carina; Oliveira, Maria Cristina; Gano, Lurdes; Marques, Fernanda; Thiemann, Thies; Santos, Isabel

2012-03-13

218

Critical fields and currents in high Tc superconductors  

NASA Astrophysics Data System (ADS)

The present evaluation of parameters characterizing the high-Tc superconductors attempts to relate these to each other. It is noted that while upper critical fields are sufficiently high for the creation of high-field magnets, the lower critical fields are likely to increase the losses associated with certain applications. Although the depairing current and reversible magnetization are theoretically good guides to current-carrying properties, the screening of materials on the basis of Tc alone may lead to the overlooking of useful current carriers. These problems are essentially those generally encountered in materials science; no theoretical reason has been identified which would preclude the carriage of useful currents by a room-temperature superconductor.

Campbell, A. M.

219

Five Possible Reasons why HIGH-Tc Superconductivity is Stalled  

NASA Astrophysics Data System (ADS)

Five commonly held premises considered questionable assumptions in the microscopic theory of superconductivity are discussed as possible reasons why the search appears to be stalled for a theoretical framework, admittedly ambitious, capable of predicting materials with critical temperatures Tc higher than the 1993 record of 164K in HgTlBaCaCuO (under pressure). We focus the dilemma as a whole in terms of a generalized Bose-Einstein condensation (GBEC) interpretation that includes and further extends BCS theory, as well as substantially enhancing its predicted Tcs within the electron-phonon mechanism producing pairing. The new GBEC model is an extension of the Friedberg-T.D. Lee 1989 boson-fermion BEC theory of high-Tc superconductors in that it includes hole pairs as well as electron pairs.

Grether, M.; de Llano, M.

220

Five Possible Reasons why HIGH-Tc Superconductivity is Stalled  

NASA Astrophysics Data System (ADS)

Five commonly held premises considered questionable assumptions in the microscopic theory of superconductivity are discussed as possible reasons why the search appears to be stalled for a theoretical framework, admittedly ambitious, capable of predicting materials with critical temperatures Tc higher than the 1993 record of 164K in HgTlBaCaCuO (under pressure). We focus the dilemma as a whole in terms of a generalized Bose-Einstein condensation (GBEC) interpretation that includes and further extends BCS theory, as well as substantially enhancing its predicted Tcs within the electron-phonon mechanism producing pairing. The new GBEC model is an extension of the Friedberg-T.D. Lee 1989 boson-fermion BEC theory of high-Tc superconductors in that it includes hole pairs as well as electron pairs.

Grether, M.; de Llano, M.

2007-09-01

221

Pragmatic performance of TC8PSK in Rician fading channels  

NASA Astrophysics Data System (ADS)

A computer simulation is used to analyze the performances of trellis coded (TC) 8PSK modulation in Rician fading channels to optimize parameters of Viterby decoders. When carrier power to multipath power ratio, C/M, equals 10 dB, Pe performance with reasonable length interleaving is shown to depend on the free Euclidian distance, d(free), but not on the effective code length (ECL) in a practical range of bit error probability. For C/M = 5 dB, the effect of ECL appears in the range of bit energy to noise power density ratio much greater than C/M. Therefore, for domestic mobile satellite communication systems for nonhigh latitude countries, only d(free) must be considered for TC8PSK Viterbi decoder design. Also, pre-Viterbi decoding maximal ratio combining is proposed to improve Pe performance in a slow fading environment.

Dohi, Tomohiro; Sakai, Tsutomu; Morikura, Masahiro; Kato, Shuzo

1991-08-01

222

Bio-application of high-Tc SQUID magnetic sensor  

NASA Astrophysics Data System (ADS)

We propose medical applications using ultra-small magnetic particles and a SQUID magnetic sensor. A high-Tc SQUID system for biological molecules (DNA) detection is one of that. This system is based on a hybridization process. Two strands in a DNA molecule are held together by hydrogen bonds between base pairs like a ladder. The two strands are referred to as being complementary to each other. One strand (sample DNA) was labeled with Fe3O4 ultra-small magnetic particles and the other (probe DNA) was anchored on a glass slide. Then they were hybridized each other on the slide. After washing the excess sample DNA, the hybridized DNA was evaluated in the presence of excitation AC field by high-Tc SQUID. The signal was initially proportional to the concentration of the sample DNA and then saturated. It means that the hybridization occurred successfully between the sample DNA and the probe DNA.

Tanaka, Saburo; Aspanut, Zarina; Kurita, Hirofumi; Toriyabe, Chika; Hatuskade, Yoshimi; Katsura, Shinji

2006-05-01

223

Technical issues of a high-Tc superconducting bulk magnet  

NASA Astrophysics Data System (ADS)

Superconducting magnets made of high-Tc superconductors are promising for industrial applications. It is well known that REBa2Cu3O7-x superconductors prepared by melt processes have a high critical current density, Jc, at 77 K and high magnetic fields. The materials are very promising for high magnetic field applications as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. Light rare-earth (LRE) BaCuO bulks, compared with REBaCuO bulks, exhibit a larger Jc in high magnetic fields and a much improved irreversibility field, Hirr, at 77 K. In this study, we discuss technical issues of a high-Tc superconducting bulk magnet, namely the aspects of the melt processing for bulk superconductors, their characteristic superconducting properties and mechanical properties, and trapped field properties of a superconducting bulk magnet. One of the possible applications is a superconducting bulk magnet for the magnetically levitated (Maglev) train in the future.

Fujimoto, Hiroyuki

2000-06-01

224

Focal uptake of Tc-99m MDP in a gossypiboma.  

PubMed

A 51-year-old Korean woman with a history of breast cancer underwent screening bone scintigraphy, which revealed minimal soft tissue uptake of Tc-99m methylene diphosphonate (MDP) in the right lower quadrant. CT and plain films confirmed that the uptake was due to a retained surgical sponge or gossypiboma. The incidence of gossypibomas has been reported at high as 1 in 1000 to 15,000 intra-abdominal operations. The natural progression of an aseptic gossypiboma is a foreign body reaction and granuloma formation. This inflammatory granulomatous reaction is the most likely cause of the extraosseous accumulation of Tc-99m MDP. This entity should be added to the already extensive list of etiologies of extraosseous MDP accumulation. PMID:18356674

Thomas, Bejoy G; Silverman, Eugene D

2008-04-01

225

Tc-99m DMSA uptake by metastatic colorectal carcinoma.  

PubMed

Extrarenal uptake of Tc-99m DMSA is not seen very often. It has previously been described in metastatic disease and was mainly attributed to the presence of V-DMSA in the injected solution. We report a clinical case of incidental visualization of metastatic bone disease of the colon in a patient with renal failure. This could be the result of not only the presence of V-DMSA, but also the renal failure and the atypia of the lesions. PMID:15249824

Rondogianni, Phivi; Koniaris, George

2004-08-01

226

Megaureter visualization on Tc-99m DMSA scintigraphy.  

PubMed

We present a patient with left-sided obstructed megaureter secondary to neuropathic bladder. He was referred for technetium-99m dimercaptosuccinic acid ((99m)Tc-DMSA) renal cortical scintigraphy to evaluate renal cortical function. Images obtained 4 hr after injection showed significant activity in the dilated left ureter. When the ureter is visualized on DMSA scan, obstructive megaureter should be considered in the differential diagnosis. PMID:16164201

Türkölmez, Seyda; Ors, Derya; Korkmaz, Meliha

2005-07-01

227

Investigation of high-Tc superconductivity by the muon method  

Microsoft Academic Search

The polarization function of positive muons was measured in the high-Tc superconductor La(1.87)Sr(0.13)CuO4. It is shown that superconductivity does not change the distribution of nuclear magnetic fields on a muon. The magnetic field penetration depth is determined to be 3200 A and the magnitude of the first critical field Hc1 is determined to be less than 15 Oe. The normal

V. G. Grebinnik; V. N. Duginov; V. A. Zhukov; A. B. Lazarev; V. G. Ol'Shevskii

1987-01-01

228

Rhenium Uptake as Analogue 96Tc by Steel Corrosion Products  

SciTech Connect

Static batch experiments were used to examine the sorption of dissolved perrhenate [Re(VII)], as a surrogate for pertechnetate [Tc(VII)], on corrosion products of A-516 carbon steel coupons contacted with synthetic groundwater or dilute water. After 109 days of contact time, the concentration of dissolved Re(VII) in the synthetic groundwater matrix decreased by approximately 26%; the dilute water matrix experienced a 99% decrease in dissolved Re(VII) over the same time period. Bulk x-ray diffraction (XRD) results for the corroded steel coupons showed that the corrosion products consisted primarily of maghemite, lepidocrocite, and goethite. Analyses of the coupons by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) indicated that Re was present with the morphologically complex assemblages of Fe oxide/hydroxide corrosion products for samples spiked with the highest dissolved Re(VII) concentration (1.0 mmol/L) used for these experiments. Analyses of corroded steel coupons contacted with solutions containing 1.0 mmol/L Re(VII) by synchrotron-based methods confirmed the presence of Re sorbed with the corrosion product on the steel coupons. Analyses showed that the Re sorbed on these corroded coupons was in the +7 oxidation state, suggesting that the Re(VII) uptake mechanism did not involve reduction of Re to a lower oxidation state, such as +4. The results of our studies using Re(VII) as an analogue for {sup 99}Tc(VII) suggest that {sup 99}Tc(VII) would also be sorbed with steel corrosion products and that the inventory of {sup 99}Tc(VII) released from breached waste packages would be lower than what is now conservatively estimated.

K.M. Krupka, C.F. Brown, H. Todd Schaef, S. M. Heald, M. M. Valenta, B. W. Arey

2006-04-30

229

Atomic Mass and Nuclear Binding Energy for Tc-99 (Technetium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Subvolume A `Nuclei with Z = 1 - 54' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Tc-99 (Technetium, atomic number Z = 43, mass number A = 99).

Sukhoruchkin, S. I.; Soroko, Z. N.

230

Binding of 99m Tc-gluconate to heart mitochondria  

Microsoft Academic Search

99mTc-gluconate has previously been shown to bind to isolated rat heart mitochondria. In the presence of potassium cyanide this binding is enhanced several fold, an effect which has been shown to be correlated to the efficiency of the in vivo binding of the isotope complex in ischemic dog hearts. The present investigation shows that the potassium cyanide-induced binding was mainly

D. Galaris; M. Grandinson; U. Söderlund; N. E. Ahlberg; J. Rydström

1983-01-01

231

High-Tc SQUID gradiometer system for immunoassays  

Microsoft Academic Search

A high-Tc dc SQUID (superconducting quantum interference device) gradiometer was developed for magnetic immunoassays where magnetic nanoparticles are used as markers to detect biological reactions. The gradiometer was fabricated on a 5 × 10 mm2 SrTiO3 bicrystal substrate and has a gradiometer resolution of 2.1 pT cm-1 Hz-1\\/2. A magnetic signal was detected from a sample of 1 µl of

F. Öisjöen; P. Magnelind; A. Kalabukhov; D. Winkler

2008-01-01

232

First-principles studies for understanding diverse high-Tc  

NASA Astrophysics Data System (ADS)

In this talk, I survey results and insights gained from first-principles calculations on materials that exhibit superconducting behavior at temperatures higher than those characteristic of conventional BCS superconductors. These range from highly correlated cuprate Mott insulators as represented by the bismuth-strontium-calcium-copper-oxides (BSCCOs) to border-line itinerant-Mott systems such as the recently discovered 1111 and 122 pnictides. ultimate goal of our studies is to correlate Tc with specific material composition using detailed first-principles calculations in conjunction with many-body physics techniques via the critical step of constructing real-materials model Hamiltonians. By manipulating impurity doping, which plays a crucial role in the phase diagrams of high Tc materials, we hope to find guidance for designing candidate systems with Tc higher than ones currently known. BSCCO material, density functional calculations using a good generalized-gradient approximation (GGA) yield structural information that is correlated to the experimentally observed (STM) super-modulation and impurity peak in the high energy regime (˜1 eV), even though the Kohn-Sham bands from such functionals fail to have a band gap. For FeAs-based high-Tc systems, DFT band-structure calculations provide a very good starting point for constructing model Hamiltonians for studies of spin fluctuation and electron pairing mechanisms. Fermi sheets that have been constructed using Wannier transformed Kohn-Sham states have provided critical information for understanding this family of superconducting materials. Analysis of the details of magnetic ordering, density of states, and 2D vs. 3D features in both the 1111 and 122 materials have been valuable in understanding sometimes perplexing experimental findings. Effects of Co impurities have been studied and fully analyzed as well., I will discuss persistent challenges related to calculations on the structure of the non-magnetic state Ba1Fe2As2 system. Both further examination of the underlying physics and development of new approximate functionals are needed.

Cheng, Hai-Ping

2011-03-01

233

Tc-99m HIDA scintigraphy in segmental biliary obstruction  

SciTech Connect

Segmental biliary obstruction as a result of primary or secondary hepatic malignancy has been reported with increasing frequency. For two representative patients, the clinical and Tc-99m HIDA scintigraphic findings in segmetal biliary obstruction are described. The presence of photon-deficient dilated bile ducts in one segment of the biliary tree is highly suggestive of localized biliary obstruction and should be considered in the patient with suspected or proven hepatic malignancy despite the absence of jaundice.

Zeman, R.K.; Gold, J.A.; Gluck, L.; Caride, V.J.; Burrell, M.; Hoffer, P.B.

1981-05-01

234

Tc-99m HIDA scintigraphy in segmental biliary obstruction  

SciTech Connect

Segmental biliary obstruction as a result of primary or secondary hepatic malignancy has been reported with increasing frequency. For two representative patients, the clinical and Tc-99m HIDA scintigraphic findings in segmental biliary obstruction are described. The presence of photon-deficient dilated bile ducts in one segment of the biliary tree is highly suggestive of localized biliary obstruction and should be considered in the patient with suspected or proven hepatic malignancy despite the absence of jaundice.

Zeman, R.K.; Gold, J.A.; Gluck, L.; Caride, V.J.; Burrell, M.; Hoffer, P.B.

1981-05-01

235

Preoperative imaging of abnormal parathyroid glands in patients with hyperparathyroid disease using combination Tc-99m-pertechnetate and Tc-99m-sestamibi radionuclide scans.  

PubMed Central

OBJECTIVE: To evaluate the efficacy of combined Tc-99m-pertechnetate and Tc-99m-sestamibi radionuclide scanning for imaging abnormal parathyroid glands in hyperparathyroid disease in a prospective study. SUMMARY BACKGROUND DATA: Established methods to localize abnormal parathyroid glands lack accuracy for routine use. Tc-99m-sestamibi used in conjunction with iodine-123 has excellent potential for preoperative imaging in patients with hyperparathyroid disease. An alternative method for parathyroid imaging was studied using Tc-99m-pertechnetate and Tc-99m-sestamibi. METHODS: Thirty patients with hyperparathyroid disease had Tc-99m-pertechnetate and Tc-99m-sestamibi subtraction radionuclide scanning to visualize abnormal parathyroid glands before surgery. The patients had surgery and pathologic confirmation of all parathyroid glands. RESULTS: In 23 patients with primary hyperparathyroidism, 12 of 13 solitary adenomas were visualized. Six of nine patients with diffuse hyperplasia had bilateral uptake consistent with diffuse hyperplasia. Three of nine patients had negative scans. One patient previously operated on for diffuse hyperplasia had only one gland scanned. Seven patients with renal failure-associated hyperparathyroid disease were scanned: five had bilateral uptake of Tc-99m-sestamibi consistent with hyperplasia, and two who had been previously operated on had localization of remaining abnormal parathyroid glands. CONCLUSIONS: Tc-99m-pertechnetate combined with Tc-99m-sestamibi subtraction radionuclide scanning is less cumbersome to implement than iodine-123 combined with Tc-99m-sestamibi scanning. It has a high sensitivity for imaging solitary parathyroid adenomas or persistent solitary hyperplastic glands. However it does not have the resolution necessary to delineate all parathyroid glands in diffuse hyperplasia. Images Figure 1. Figure 2.

Wei, J P; Burke, G J; Mansberger, A R

1994-01-01

236

New routes for production of proton-rich Tc isotopes  

SciTech Connect

Proton-rich Tc radionuclides have been identified as potential candidates for specific clinical and biological applications in the last decade. So far, these radionuclides have been produced either by proton-induced reaction on Mo targets or {alpha}-particle-induced reaction on Nb targets. This article lightens two heavy-ion-induced production routes of {sup 93,94,95,96}Tc radionuclides through {sup 7}Li+{sup nat}Zr and {sup 9}Be+{sup nat}Y reactions and provides important cross-sectional information in the projectile energy ranges 37-45 MeV and 30-48 MeV, respectively. Excitation functions of those reactions have been measured using the stacked-foil technique followed by the off-line {gamma}-spectrometric studies. Measured cross-sectional data have been interpreted comparing theoretical predictions of the two nuclear reaction model codes PACE-II and ALICE91. Experimental cross sections agreed with the theory. Measured production cross sections of {sup 94,95}Tc have been compared with those produced from the {alpha}+{sup 93}Nb reaction.

Maiti, Moumita; Lahiri, Susanta [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700 064 (India)

2010-02-15

237

Tc-99m DTPA renal scintigraphy using deconvolution analysis with six functional images of the mean time to evaluate acute pyelonephritis.  

PubMed

In 38 children with proved P-fimbriated Escherichia coli acute pyelonephritis, Tc-99m DTPA dynamic renal scintigraphy in the zoom mode using deconvolution analysis was performed, and the results were compared with those of Tc-99m DMSA scans. From the dynamic study, six functional images of the mean time were generated. Each functional image was analyzed separately to search for focal areas of increased mean time within the kidney contour, especially over the kidney parenchyma. Time-activity curves from these areas were generated and analyzed. Tc-99m DMSA scintigraphy showed generalized or focal decreased uptake in 32 (41.8%) kidneys, and deconvolution analysis of Tc-99m DTPA scintigraphy revealed pathologic renographic curves in 58 (77.6%) kidneys. Prolonged whole-kidney and normal renal parenchymal transit times (dilatation without obstruction) were found in 38 (50%) kidneys, whereas prolonged whole-kidney and renal parenchymal transit times (dilatation with obstruction) were observed in 20 (27.6%) kidneys. Separate analysis of each of the six functional images of the mean time showed focal areas of increased mean time in the kidney parenchyma of 11 kidneys. In five cases, time-activity curves from these areas showed a sharp increase of activity on the descending part of the curve, which might reflect the return of urine from the collecting system into kidney cortex (i.e., intrarenal reflux). These results showed that in a urinary tract with acute pyelonephritis, urodynamic changes may lead to obstructive nephropathy and intrarenal reflux. Tc-99m DTPA renal scintigraphy in the zoom mode using deconvolution analysis with six functional images of the mean time has proved to be a valuable method to evaluate acute pyelonephritis, thus allowing dynamic and morphologic analysis of the urinary tract at the same time. PMID:9988072

Poropat, M; Batini?, D; Basi?, M; Nizi?, L J; Dodig, D; Milosevi?, D; Votava-Rai?, A; Tezak, S; Vrljicak, K; Hui?, D; Medvedec, M

1999-02-01

238

Chart Generation  

Microsoft Academic Search

Charts constitute a natural uniform architecture for parsing and generation provided string position is replaced by a notion more appropriate to logical forms and that measures are taken to curtail generation paths containing semantically incomplete phrases.

Martin Kay

1996-01-01

239

Study on Effective Average (?, n) Cross Section for Y, Zr, Nb, and Cs and (?, 3n) Cross Section for Tc  

Microsoft Academic Search

A nondestructive detection technique was proposed for the easy assessment of long-lived radionuclides by the use of bremsstrahlung photons. The nuclide of Tc was considered for the assessment over an effective average Tc (?, 3n) Tc cross section. For validating the experimental method on Tc, photonuclear (?, n) cross sections of Y, Zr, Nb, and Cs were measured. Continuous-energy bremsstralung

Kunio KATO; Hidehiko ARIMA; Nobuhiro SHIGYO; Kenji ISHIBASHI; Jun-ichi HORI; Ken NAKAJIMA

2010-01-01

240

A comparison of bone imaging with Tc-99m DPD and Tc-99m MDP: concise communication  

SciTech Connect

Bone to soft tissue (ST) ratios for both high-uptake bone (sacrum) and low-uptake bone (femoral diaphysis) were obtained with a derivative of phosphonic acid, TC-99m 2,3-dicarboxypropane-1, 1-diphosphonate (DPD), in 26 normal subjects and 177 patients with malignant disease but without metastases. Tests were run 2 hr after tracer injection. Similar ratios were obtained with Tc-99m methylene diphosphonate (MDP) in 220 normal subjects and 451 patients. With MDP, the influence of incubation time (5-10 min in 416 cases, 45 min in 185 cases) on these ratios was determined. DPD was superior to MDP for both ratios. With MDP, prolonged incubation time yielded significantly enhanced ratios; however, the ratios for the DPD were still higher. With either agent and preparation, sacrum-to-ST ratios decreased with increasing subject age, and in patients with malignant disease the ratios tended to be higher than those obtained from normals.

Buell, U.; Kleinhans, E.; Zorn-Bopp, E.; Reuschel, W.; Muenzing, W.; Moser, E.A.; Seiderer, M.

1982-03-01

241

Evaluation of a HER2-targeting affibody molecule combining an N-terminal HEHEHE-tag with a GGGC chelator for 99mTc-labelling at the C terminus.  

PubMed

Affibody molecules are a class of small (ca.7 kDa) robust scaffold proteins with high potential as tracers for radionuclide molecular imaging in vivo. Incorporation of a cysteine-containing peptide-based chelator at the C terminus provides an opportunity for stable labelling with the radionuclide (99m)Tc. The use of a GGGC chelator at the C terminus has provided the lowest renal radioactivity retention of the previously investigated peptide-based chelators. Previously, it has also been demonstrated that replacement of the His(6)-tag with the negatively charged histidine-glutamate-histidine-glutamate-histidine-glutamate (HEHEHE)-tag permits purification of affibody molecules by immobilized metal ion affinity chromatography (IMAC) and provides low hepatic accumulation of radioactivity of conjugates site-specifically labelled at the C terminus using several different nuclides. We hypothesized that the combination of a HEHEHE-tag at the N terminus and a GGGC chelator at the C terminus of an affibody molecule would be a favourable format permitting IMAC purification and providing low uptake in excretory organs. To investigate this hypothesis, a (HE)(3)-Z(HER2:342)-GGGC affibody molecule was generated. It could be efficiently purified by IMAC and stably labelled with (99m)Tc. (99m)Tc-(HE)(3)-Z(HER2:342)-GGGC preserved specific binding to HER2-expressing cells. In NMRI mice, hepatic uptake of (99m)Tc-(HE)(3)-Z(HER2:342)-GGGC was lower than the uptake of the control affibody molecules, (99m)Tc-Z(HER2:2395)-VDC and (99m)Tc-Z(HER2:342)-GGGC. At 1 and 4 h after injection, the renal uptake of (99m)Tc-(HE)(3)-Z(HER2:342)-GGGC was 2-3-fold lower than uptake of (99m)Tc-Z(HER2:2395)-VDC, but it was substantially higher than uptake of (99m)Tc-Z(HER2:342)-GGGC. Further investigation indicated that a fraction of (99m)Tc was chelated by the HEHEHE-tag which caused a higher accumulation of radioactivity in the kidneys. Thus, a combination of a HEHEHE-tag and the GGGC chelator in targeting scaffold proteins was found to be undesirable in the case of (99m)Tc labelling due to a partial loss of site-specificity of nuclide chelation. PMID:22249974

Lindberg, Hanna; Hofström, Camilla; Altai, Mohamed; Honorvar, Hadis; Wållberg, Helena; Orlova, Anna; Ståhl, Stefan; Gräslund, Torbjörn; Tolmachev, Vladimir

2012-01-17

242

Studies of the retention mechanism of the brain perfusion imaging agent {sup 99m}{Tc}-bicisate ({sup 99m}{Tc}-ECD)  

SciTech Connect

The structure-activity relationship in a series of analogues of {sup 99m}{Tc}-bicisate ({sup 99m}{Tc}-N,N{prime}-1,2-ethylene-diylbis-L-cysteine diethyl ester dihydrochloride, RP-217) is described using in vivo studies in rodent and primate brain tissue. All analogues investigated were {sup 99m}{Tc}-diamine dithiol diesters, which were neutral and lipophilic and had modified brain uptake indexes ({ge}40) suggesting adequate first-pass extraction. All analogues were poorly retained by the rodent brain. In contrast, the stereochemistry and structure of the {sup 99m}{Tc}-complexes affected their brain retention in primates. All compounds that demonstrated selective primate brain retention were L-diesters that were metabolized in primate brain tissue to nonlypophilic complexes resulted from ester hydrolysis. Unretained complexes were not metabolized in primate brain tissue. More extensive studies were performed with {sup 99m}{Tc}-bicisate, which demonstrated poor brain retention in several nonprimate species (i.e., dogs, ferrets, pigs, and rodents). In rodent and nonhuman primate tissue, {sup 99m}{Tc}-bicisate was rapidly metabolized to a monoacid ester ({sup 99m}{Tc}-N,N{prime}-1,2-ethylenediylbis-L-cysteine monoethyl ester). Therefore, brain metabolism of {sup 99m}{Tc}-bicisate results in the formation of an acid product(s) that is selectively trapped in primate brain. 20 refs., 2 figs., 4 tabs.

Walovitch, R.C.; Cheesman, E.H.; Maheu, L.J.; Hall, K.M. [DuPont Merck Pharmaceutical Co., North Billerica, MA (United States)

1994-01-01

243

Neutron powder diffraction of the superconductor TlBa2Ca2Cu3O8+? with different maximum TC values (TC = 120 132 K)  

NASA Astrophysics Data System (ADS)

The crystal structure of the high-TC superconductor TlBa2Ca2Cu3O8+? with different maximum TC values (~132, 126 and 120 K) is investigated by neutron powder diffraction measurements. The refined values of occupancy for the excess oxygen(?) located in interstitial positions on the Tl-O layer, O(4), are 0.775(6), 0.751(16) and 0.813(25) for the samples with a maximum TC of ~132, 126 and 120 K, respectively. It is found that the Cu(2)-O(3) bond lengths of samples with higher TC are shorter, and the value of this bond length for the Tl-1223 sample with a TC of ~132 K is almost equal to that for Hg-1223 with a maximum TC of ~135 K. It is also found that the flatness of the CuO2 planes increases with increasing TC. It appears that the structural features of the CuO5 pyramids are among the factors contributing to the higher value of TC in cuprate superconductors.

Mikusu, S.; Takami, S.; Tokiwa, K.; Takeuchi, K.; Iyo, A.; Tanaka, Y.; Watanabe, T.

2008-08-01

244

Characterization of a Novel Tc1Like Transposon From Bream (Cyprinidae, Megalobrama ) and Its Genetic Variation in the Polyploidy Progeny of Bream–Red Crucian Carp Crosses  

Microsoft Academic Search

Crossing the cyprinids diploid blunt snout bream Megalobrama amblycephala (BSB) and Carassius auratus red var. (RCC) generated sterile triploid (3nRB) and fertile tetraploid (4nRB) hybrid offspring. Utilizing inverted terminal\\u000a repeats (ITRs) of transposon Tdr1 from Danio rerio as PCR primer, the results showed that evident change in the number of Tc1-like transposons in 4nRB relative to BSB occurred,\\u000a whereas such

Dong LiuCuiping YouShaojun Liu; Cuiping You; Shaojun Liu; Liangguo Liu; Wei Duan; Song Chen; Jinpeng Yan; Yun Liu

2009-01-01

245

A Novel Ternary Ligand System Useful for Preparation of Cationic 99mTc-Diazenido Complexes and 99mTc-Labeling of Small Biomolecules  

PubMed Central

This report describes a novel ternary ligand system composed of a phenylhydrazine, a crown ether-containing dithiocarbamate (DTC) and a PNP-type bisphosphine (PNP). The combination of three different ligands with 99mTc results in cationic 99mTc-diazenido complexes,[99mTc(NNAr)(DTC)(PNP)]+, with potential radiopharmaceuticals for heart imaging. Synthesis of cationic 99mTc-diazenido complexes can be accomplished in two steps with high yield. For example, the reaction of phenylhydrazine with 99mTcO4? at 100 °C in the presence of excess stannous chloride and 1,2-diaminopropane-N,N,N’,N’-tetraacetic acid (PDTA) results in the [99mTc(NNPh)(PDTA)n] intermediate, which then reacts with sodium N-(dithiocarbamato)-2-aminimethyl-15-Crown-5 (L4) and N,N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]ethoxy-ethylamine (PNP6) at 100 °C for 15 min to give the complex, [99mTc(NNPh)(L4)(PNP6)]+ in high yield (> 90%). Cationic complexes [99mTc(NNPh)(DTC)(PNP)]+ are stable for ?6 h. Their composition was determined to be 1:1:1:1 for Tc:NNPh:DTC:PNP using the mixed-ligand experiments on the tracer (99mTc) level, and was further confirmed by the ESI-MS spectral data of a model compound [Re(NNPh)(L4)(L6)]+. It was found that both DTCs and bisphosphines have a significant impact on the lipophilicity of their cationic 99mTc-diazenido complexes. Results from a 99mTc-labeling efficiency experiment showed that 4-hydrazinobenzoic acid (HYBA) might be useful as a bifunctional coupling agent for 99mTc-labeling of small biomolecules. However, the 99mTc-labeling efficiency of HYBA is much lower than that of 6-hydrazinonicotinic acid (HYNIC) with tricine and trisodium triphenylphosphine-3,3’,3”-trisulfonate (TPPTS) as coligands.

Kim, Young-Seung; He, Zhengjie; Hsieh, Wen-Yuan; Liu, Shuang

2008-01-01

246

Development of more efficacious Tc-99m organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures  

SciTech Connect

The long-range objective of this research program is the development of more efficacious technetium-99m radiopharmaceuticals for use as imaging agents in diagnostic nuclear medicine. We seek to isolate and develop distinct site imaging agents, each of which has properties optimized to provide diagnostic information concerning a given pathological condition. The specific objectives during the period (9/1/89 to 8/31/92) include: (1) Development of strategies for improving yields of specific Tc-diphosphonate complexes with optimum imaging properties; (2) Development of electrodes for rapid in situ electrochemical generation of skeletal imaging agents; (3) Development of electrochemical sensors for {Tc} and Re imaging agents; (4) Characterization of stable {Tc}- and Re-diphosphonate complexes obtainable in high yield by structural studies with techniques such as NMR, EXAFS, and Raman spectroscopy; (5) Development of improved separation techniques for the characterization of diphosphonate skeletal imaging agents; (6) Evaluation of the effect of the biological milieu on {Tc}-diphosphonate complexes; and (7) Electrochemical studies of technetium and rhenium complexes synthesized by Professor Deutsch's research group for heart and brain imaging.

Heineman, W.R.

1992-01-24

247

Nuclear shape and structure in neutron-rich {sup 110,111}Tc  

SciTech Connect

The high-spin nuclear structure of Tc isotopes is extended to more neutron-rich regions based on the measurements of prompt {gamma} rays from the spontaneous fission of {sup 252}Cf at the Gammasphere. The high-spin level scheme of N=67 neutron-rich {sup 110}Tc (Z=43) is established for the first time, and that of {sup 111}Tc is extended and expanded. The ground band of {sup 111}Tc reaches the band-crossing region, and the new observation of the weakly populated {alpha}=-1/2 member of the band provides important information on signature splitting. The systematics of band crossings in the isotopic and isotonic chains and a CSM calculation suggest that the band crossing of the ground band of {sup 111}Tc is due to alignment of a pair of h{sub 11/2} neutrons. The best fit to signature splitting, branching ratios, and excitations of the ground band of {sup 111}Tc by the rigid triaxial rotor plus particle model calculations result in a shape of {epsilon}{sub 2}=0.32 and {gamma}=-26 deg. for this nucleus. Its triaxiality is larger than that of {sup 107,109}Tc, which indicates increasing triaxiality in Tc isotopes with increasing neutron number. The identification of the weakly populated K+2 satellite band provides strong evidence for the large triaxiality of {sup 111}Tc. In {sup 110}Tc, the four lowest-lying levels observed are very similar to those in {sup 108}Tc. At an excitation of 478.9 keV above the lowest state observed, ten states of a {delta}I=1 band are observed. This band of {sup 110}Tc is very analogous to the {delta}I=1 bands in {sup 106,108}Tc, but it has greater and reversal signature splitting at higher spins.

Luo, Y. X. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Gore, P. M.; Jones, E. F.; Fong, D. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Stefanescu, I. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Che, X. L. [Physics Department, Tsinghua University, Beijing 100084 (China); Zhu, S. J. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States); Physics Department, Tsinghua University, Beijing 100084 (China); Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831 (United States); Wu, S. C. [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Ginter, T. N. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Ma, W. C. [Mississippi State University, Drawer 5167, Mississippi State, Mississippi 39762 (United States); Ter-Akopian, G. M.; Daniel, A. V. [Flerov Laboratory for Nuclear Reactions, JINR, Dubna (Russian Federation); Stoyer, M. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Donangelo, R. [Universidade Federal do Rio de Janeiro, CP 68528, RG (Brazil); Gelberg, A. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937, Cologne (Germany)

2006-08-15

248

Nuclear shape and structure in neutron-rich Tc110,111  

NASA Astrophysics Data System (ADS)

The high-spin nuclear structure of Tc isotopes is extended to more neutron-rich regions based on the measurements of prompt ? rays from the spontaneous fission of Cf252 at the Gammasphere. The high-spin level scheme of N=67 neutron-rich Tc110 (Z=43) is established for the first time, and that of Tc111 is extended and expanded. The ground band of Tc111 reaches the band-crossing region, and the new observation of the weakly populated ?=-1/2 member of the band provides important information on signature splitting. The systematics of band crossings in the isotopic and isotonic chains and a CSM calculation suggest that the band crossing of the ground band of Tc111 is due to alignment of a pair of h11/2 neutrons. The best fit to signature splitting, branching ratios, and excitations of the ground band of Tc111 by the rigid triaxial rotor plus particle model calculations result in a shape of ?2=0.32 and ?=-26° for this nucleus. Its triaxiality is larger than that of Tc107,109, which indicates increasing triaxiality in Tc isotopes with increasing neutron number. The identification of the weakly populated K+2 satellite band provides strong evidence for the large triaxiality of Tc111. In Tc110, the four lowest-lying levels observed are very similar to those in Tc108. At an excitation of 478.9 keV above the lowest state observed, ten states of a ?I=1 band are observed. This band of Tc110 is very analogous to the ?I=1 bands in Tc106,108, but it has greater and reversal signature splitting at higher spins.

Luo, Y. X.; Hamilton, J. H.; Rasmussen, J. O.; Ramayya, A. V.; Stefanescu, I.; Hwang, J. K.; Che, X. L.; Zhu, S. J.; Gore, P. M.; Jones, E. F.; Fong, D.; Wu, S. C.; Lee, I. Y.; Ginter, T. N.; Ma, W. C.; Ter-Akopian, G. M.; Daniel, A. V.; Stoyer, M. A.; Donangelo, R.; Gelberg, A.

2006-08-01

249

A variant Tc4 transposable element in the nematode C. elegans could encode a novel protein.  

PubMed Central

A variant C. elegans Tc4 transposable element, Tc4-rh1030, has been sequenced and is 3483 bp long. The Tc4 element that had been analyzed previously is 1605 bp long, consists of two 774-bp nearly perfect inverted terminal repeats connected by a 57-bp loop, and lacks significant open reading frames. In Tc4-rh1030, by comparison, a 2343-bp novel sequence is present in place of a 477-bp segment in one of the inverted repeats. The novel sequence of Tc4-rh1030 is present about five times per haploid genome and is invariably associated with Tc4 elements; we have used the designation Tc4v to denote this variant subfamily of Tc4 elements. Sequence analysis of three cDNA clones suggests that a Tc4v element contains at least five exons that could encode a novel basic protein of 537 amino acid residues. On northern blots, a 1.6-kb Tc4v-specific transcript was detected in the mutator strain TR679 but not in the wild-type strain N2; Tc4 elements are known to transpose in TR679 but appear to be quiescent in N2. We have analyzed transcripts produced by an unc-33 gene that has the Tc4-rh1030 insertional mutation in its transcribed region; all or almost all of the Tc4v sequence is frequently spliced out of the mutant unc-33 transcripts, sometimes by means of non-consensus splice acceptor sites. Images

Li, W; Shaw, J E

1993-01-01

250

An X-ray absorption spectroscopy study of the coprecipitation of Tc and Re with mackinawite (FeS)  

Microsoft Academic Search

X-ray absorption spectroscopy (XAS) has been used to define the local chemical environments of Tc and its proposed chemical analogue Re in precipitates of mackinawite (tetragonal FeS) and its oxidation products. Pertechnetate, [TcO4]?, is reduced to Tc(IV) on coprecipitation with FeS, while Tc(IV) undergoes no redox change. A TcS2-like phase is formed in both cases. On oxidation of the host

M. J Wharton; B Atkins; J. M Charnock; F. R Livens; R. A. D Pattrick; D Collison

2000-01-01

251

Vapor generator  

SciTech Connect

The present invention relates to a solar central receiver or steam generating and superheating unit comprised of a first and a second series of circularly disposed tube panels. THe first series includes steam superheating tube panels and the second series includes steam generating tube panels (16-16'). The steam generating tube panels being interposed between at least some of the steam superheating panels and the solar heat source.

Wiener, M.

1981-01-20

252

Is there still a need for Tc-99m DMSA renal imaging?  

PubMed

Scintigraphy with Tc-99m MAG3 is, to date, the most commonly used technique for evaluating separate renal function (SRF). In this study, the performance of this technique is compared to Tc-99m DMSA. A total of 37 patients with various kidney disorders (12 children and 25 adults) underwent both Tc-99m DMSA and Tc-99m MAG 3 scintigraphy. In children and adults of normal weight the correlation coefficient between the two methods was 0.99 (P < 0.001), whereas in individuals who were more than 10% overweight according to Broca, or who had abnormal anatomical positions of the kidneys, the correlation coefficient was 0.82 (P < 0.05). Scintigraphy with Tc-99m DMSA was more accurate in renal parenchyma lesions. These results indicate that Tc-99m DMSA scintigraphy is preferable for the evaluation of SRF in patients who are more than 10% overweight, or have abnormal positions of the kidneys. PMID:7895429

Bair, H J; Becker, W; Schott, G; Kühn, R H; Wolf, F

1995-01-01

253

Development of 99mTc-N4-NIM for Molecular Imaging of Tumor Hypoxia  

PubMed Central

The nitro group of 2-nitroimidazole (NIM) enters the tumor cells and is bioreductively activated and fixed in the hypoxia cells. 1,4,8,11-tetraazacyclotetradecane (N4) has shown to be a stable chelator for 99mTc. The present study was aimed to develop 99mTc-cyclam-2-nitroimidazole (99mTc-N4-NIM) for tumor hypoxia imaging. N4-NIM precursor was synthesized by reacting N4-oxalate and 1,3-dibromopropane-NIM, yielded 14% (total synthesis). Cell uptake of 99mTc-N4-NIM and 99mTc-N4 was obtained in 13762 rat mammary tumor cells and mesothelioma cells in 6-well plates. Tissue distribution of 99mTc-N4-NIM was evaluated in breast-tumor-bearing rats at 0.5–4?hrs. Tumor oxygen tension was measured using an oxygen probe. Planar imaging was performed in the tumor-bearing rat and rabbit models. Radiochemical purity of 99mTc-N4-NIM was >96% by HPLC. Cell uptake of 99mTc-N4-NIM was higher than 99mTc-N4 in both cell lines. Biodistribution of 99mTc-N4-NIM showed increased tumor-to-blood and tumor-to-muscle count density ratios as a function of time. Oxygen tension in tumor tissue was 6–10?mmHg compared to 40–50?mmHg in normal muscle tissue. Planar imaging studies confirmed that the tumors could be visualized clearly with 99mTc-N4-NIM in animal models. Efficient synthesis of N4-NIM was achieved. 99mTc-N4-NIM is a novel hypoxic probe and may be useful in evaluating cancer therapy.

Ali, Mohammad S.; Kong, Fan-Lin; Rollo, Alex; Mendez, Richard; Kohanim, Saady; Smith, Daniel Lee; Yang, David J.

2012-01-01

254

Tc99m tetrofosmin: A new diagnostic tracer for parathyroid imaging  

Microsoft Academic Search

A 42-year-old woman with hyperparathyroidism had a CT scan that was suggestive of a small nodular lesion in the left lower neck. Tc-99m sestamibi and Tc-99m tetrofosmin parathyroid imaging were performed 10 minutes and 2 hours after tracer injection. Early imaging with Tc-99m sestamibi demonstrated thyroid and focal uptake in the left lower neck. On delayed imaging, finding suggested a

Masatoshi Ishibashi; Tsutomu Kumabe; Seiichiro Morita; FUMIKA MATOBA; GAKUJI NOMURA; NAOFUMI HAYABUCHI

1995-01-01

255

A 99mTc-Labeled Triphenylphosphonium Derivative for the Early Detection of Breast Tumors  

PubMed Central

Abstract Introduction A greater mitochondrial membrane potential in tumor cells has been shown to enhance the accumulation of triphenyl phosphonium derivatives. The aim of this study was to synthesize and characterize 99mTc-labeled alkyl triphenyl phosphonium (99mTc-Mito10-MAG3) for the early detection of breast tumors. Methods Mito10-MAG3 was synthesized by coupling (10-aminodecyl)triphenyl phosphonium bromide with NHS-MAG3 and radiolabeled with 99mTc. Biodistribution and pharmacokinetics of 99mTc-Mito10-MAG3 was investigated in female Sprague-Dawley rats. Initially, 99mTc-Mito10-MAG3 was tested in animals with established breast tumors. In a subsequent longitudinal study, the imaging efficacy of 99mTc10-Mito-MAG3 for detecting small, nonpalpable breast tumors was assessed after chemically inducting breast carcinoma. Tumors detected by imaging were allowed to grow to palpable size and confirmed by histology. The results were compared with 99mTc-MIBI. Results The synthesis of Mito10-MAG3 was confirmed by mass spectrometry. The compound was radiolabeled with 99mTc to >?92% in a single step. The radiopharmaceutical exhibited fast blood clearance and low cardiac uptake. In the initial study, using animals with established breast tumors, 99mTc-Mito10-MAG3 imaging detected small lesions that were missed by palpation. In the longitudinal study, 99mTc-Mito10-MAG3 exhibited focal uptake in small breast tumors, which were confirmed by histology. Conclusions Imaging, using 99mTc-Mito10-MAG3, allowed the early detection of small neoplastic lesions in the mammary glands. The agent significantly reduced cardiac uptake, compared with 99mTc-MBIB. The phosphonium-based derivatives warrant further characterization and development as imaging agents for scintimammography.

Li, Zhixin; Lopez, Marcos; Hardy, Micael; McAllister, Donna M.; Kalyanaraman, Balaraman

2009-01-01

256

Receptor Measurements via Tc-GSA Kinetic Modeling Are Proportional to Functional Hepatocellular Mass  

Microsoft Academic Search

Kinetic modeling of 99mTc-diethylenetriaminepentaacetic acid galactosyl human serum albumin (Tc-GSA) measures the total amount of asialoglycoprotein receptor within a subject's liver. This study tested the hypothesis that the amount of asialogly- coprotein receptor measured by Tc-GSA modeling provides a valid index of functional liver mass. Methods: Twenty-two pa- tients with cirrhosis, 18 patients with chronic hepatitis, and 9 patients with

Kenji Miki; Keiichi Kubota; Yusuke Inoue; David R. Vera; Masatoshi Makuuchi

257

Leaching Tc99 from SRP glass in simulated tuff and salt groundwaters  

Microsoft Academic Search

Results of leach tests with Tc-99 doped SRP borosilicate waste glass are presented. The glass was prepared by melting a mixture of SRP 165 powdered frit doped with a carrier free solution of Tc-99 at 1150Ā°C. Dissolution of portions of the resulting glass indicated that the Tc-99 was distributed homogeneously throughout the glass. Static leach tests up to 90 days

N. E. Bibler; A. R. Jurgensen

1987-01-01

258

Development of resin-bead isotope-dilution mass spectrometric techniques for Tc99 analysis  

Microsoft Academic Search

An isotope dilution mass spectrometric method was developed for the analysis of Tc-99 after isolating it onto anion exchange resin beads. A single resin bead containing Tc-99 and Tc-97 spike is loaded onto a rhenium V-shaped filament for thermal emission mass spectrometry. The application of this technique requires the use of a mass spectrometer of high abundance sensitivity and pulse

1979-01-01

259

The identification of FeS 2 as a sorption sink for Tc(IV)  

Microsoft Academic Search

In [Maes, A., Bruggeman, C., Geraedts, K., Vancluysen, J., 2003. Quantification of the interaction of Tc with dissolved boom clay humic substances. Environ. Sci. Technol., 37, 747–753] the interaction of Tc(IV) with dissolved boom clay humic substances was quantified by the interpretation of the solid–liquid distribution of Tc in boom clay batch suspensions using a modified Schubert approach. During this

C. Bruggeman; A. Maes; J. Vancluysen

2007-01-01

260

Comparison of the radiopharmaceutical potentials of dithizone radiolabeled with 131 I and with 99m Tc  

Microsoft Academic Search

In this study, dithizone (diphenylthiocarbazone) has been separately radiolabeled with 131I and with 99mTc for preliminarily testing their radiopharmaceutical potentials on male albino rabbits. 131I-dithizone and 99mTc-dithizone were intravenously injected to rabbits via their ear veins after anesthetizing with a mixture of Alfazyne and\\u000a Alfamine (Serva) to determine their dynamic and static statuses in the metabolism. Also, 99mTc as pertechnetate

T. Ünak; Y. Yildirim; U. Avcibasi; Z. Biber; Y. Duman; P. Ünak

2007-01-01

261

Imaging of bacterial infection with 99m Tc-labeled HBD-1  

Microsoft Academic Search

The aim of this study was to evaluate 99mTc labeled human ?-defensin-1 (HBD-1) for discrimination between bacterial infection and sterile inflammation. For this purpose,\\u000a HBD-1 was radiolabeled with 99mTc and its in vivo distribution was evaluated in inflamed rats with Staphylococcus aureus (S. aureus) and sterile inflamed rats with turpentine oil. After injection into inflamed and sterile inflamed rats, 99mTc-HBD-1

F. Yurt Lambrecht; O. Yilmaz; P. Unak; B. Seyitoglu; K. Durkan; S. Yolcular; H. Baskin

2008-01-01

262

Scintigraphic imaging with a peptide glucuronide in rabbits: 99mTc exorphin C glucuronide  

Microsoft Academic Search

A peptide glucuronide (Exorphin C glucuronide) was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Scintigraphic imaging was performed in male Albino rabbits. Exorphin C glucuronide showed rapid and efficient labeling with 99mTc using glucoheptonate as a bifunctional chelate. Results demonstrated that 99mTc-GEG may be a useful new type of glucuronide derivative of peptides for diagnosis of

T. Ertay; P. Ünak; F. Z. Biber; C. Tasc?; F. Zihnio?lu; H. Durak

2007-01-01

263

99m Tc-glucoheptonate-guanine: Synthesis, biodistribution and imaging in animals  

Microsoft Academic Search

The aim of the current study was to design a nucleotide-based radiopharmaceutical which could be labeled with 99mTc and to investigate its radiopharmaceutical efficiency and stability. GHA (glucoheptonate) was used as bifunctional chelate.\\u000a GHA was labeled with 99mTc by SnCl2 reduction method first, and then G (guanine) was conjugated with 99mTc-GHA at 90 °C. In order to determine its radiopharmaceutical

P. Unak; S. Teksoz; F. Z. Biber Muftuler; E. I. Medine; C. Acar; Y. Yurekli

2008-01-01

264

Hidden Fermi liquid: The secret of high- Tc cuprates  

NASA Astrophysics Data System (ADS)

I present a formalism for dealing directly with the effects of the Gutzwiller projection implicit in the t-J model which is widely believed to underlie the phenomenology of the high- Tc cuprates. I suggest that a true BCS condensation from a Fermi-liquid state takes place but in the unphysical space prior to projection. The theory which results upon projection does not follow conventional rules of diagram theory and in fact in the normal state is a Z=0 non-Fermi liquid. Anomalous properties of the “strange metal” normal state are predicted and compared to experiments.

Anderson, P. W.

2008-11-01

265

Power Systems Development Facility Gasification Test Run TC10  

SciTech Connect

This report discusses Test Campaign TC10 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier during TC10 in air- (mainly for transitions and problematic operations) and oxygen-blown mode. Test Run TC10 was started on November 16, 2002, and completed on December 18, 2002. During oxygen-blown operations, gasifier temperatures varied between 1,675 and 1,825 F at pressures from 150 to 180 psig. After initial adjustments were made to reduce the feed rate, operations with the new fluidized coal feeder were stable with about half of the total coalfeed rate through the new feeder. However, the new fluidized-bed coal feeder proved to be difficult to control at low feed rates. Later the coal mills and original coal feeder experienced difficulties due to a high moisture content in the coal from heavy rains. Additional operational difficulties were experienced when several of the pressure sensing taps in the gasifier plugged. As the run progressed, modifications to the mills (to address processing the wet coal) resulted in a much larger feed size. This eventually resulted in the accumulation of large particles in the circulating solids causing operational instabilities in the standpipe and loop seal. Despite problems with the coal mills, coal feeder, pressure tap nozzles and the standpipe, the gasifier did experience short periods of stability during oxygenblown operations. During these periods, the syngas quality was high. During TC10, the gasifier gasified over 609 tons of Powder River Basin subbituminous coal and accumulated a total of 416 hours of coal feed, over 293 hours of which were in oxygen-blown operation. No sorbent was used during the run.

Southern Company Services

2002-12-30

266

Intrinsic Josephson effects in high-Tc superconductors  

Microsoft Academic Search

We have investigated the coupling between CuO2 layers in high-Tc superconductors by direct measurements of all dc and ac Josephson effects with current flow in the c-axis direction. The measurements have been performed on small single crystals of Bi2Sr2CaCu2O8, (PbyBi1-y)2Sr2CaCu2O8, Tl2Ba2Ca2Cu3O10, and YBa2Cu3O7-x and on a-axis-oriented YBa2Cu2O7 thin films. The results clearly show that all materials behave like stacks of

R. Kleiner; P. Müller

1994-01-01

267

Coherence lengths and penetration depths in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

The important features of the high-Tc superconductors are the 2-dimensional (2-D) layers of superconducting sheets with 2-D Cooper pairs. It has been shown recently that the BCS theory may be applicable to these systems. The coherence lengths ? and penetration depths ? have been calculated by adapting the standard theory to 2-D anisotropic systems. Our theoretical results, ?a = 34A?, ?c = 6A??a = 400A? and?c = 2300A?, are consistent with the experimental values of 30, 5, 400 and 3000A?for YBa2Cu3O7.

Tsang, T.

1992-11-01

268

Microstructures and critical currents in high-{Tc} superconductors  

SciTech Connect

Microstructural defects are the primary determining factors for the values of critical-current densities in a high {Tc} superconductor after the electronic anisotropy along the a-b plane and the c-direction. A review is made to assess firstly what would be the maximum achievable critical-current density in YBa{sub 2}Cu{sub 3}O{sub 7} if nearly ideal pinning sites were introduced and secondly what types of pinning defects are currently introduced or exist in YBa{sub 2}Cu{sub 3}O{sub 7} and how effective are these in pinning vortices.

Suenaga, Masaki

1998-11-01

269

Comparison of ??mTc-N-DBODC5 and ??mTc-MIBI of myocardial perfusion imaging for diagnosis of coronary artery disease.  

PubMed

Despite recent advances in therapeutic and diagnostic approaches, coronary artery disease (CAD) and its related cardiac disorders represent the most common cause of death in the United States. Nuclear myocardial perfusion imaging (MPI) technologies play a pivotal role in the diagnosis and treatment design for CAD. Recently, in order to develop improved MPI agents for diagnosis of CAD, (99m)Tc-[bis(dimethoxypropylphosphinoethyl)-ethoxyethyl-amine(PNP5)]-[bis(N-ethoxyethyl)dithiocarbamato(DBODC)]nitride(N-DBODC5)((99m)Tc-N-DBODC5) with a faster liver clearance than conventional single-photon emission computed tomography (SPECT) imaging agents (technetium 99m sestamibi ((99m)Tc-MIBI) or technetium 99m tetrofosmin) has been introduced. In preclinical and phase I studies, (99m)Tc-N-DBODC5 has shown characteristics of an essentially ideal MPI tracer. Importantly, however, there is no data to support the use of (99m)Tc-N-DBODC5 to evaluate myocardial ischemia in patients with suspected CAD. The present study was designed to assess the clinical value of this agent; the findings of stress and rest MPI after the administration of this agent were compared to those of stress and rest (99m)Tc-MIBI, as well as those of coronary angiography, with respect to the detection of CAD. Our findings indicated the usefulness of (99m)Tc-N-DBODC5 as a promising MPI agent. PMID:23841052

Ma, Haiyan; Li, Sijin; Wu, Zhifang; Liu, Jianzhong; Liu, Haiyan; Guo, Xiaoshan

2013-06-11

270

Comparison of 99mTc-N-DBODC5 and 99mTc-MIBI of Myocardial Perfusion Imaging for Diagnosis of Coronary Artery Disease  

PubMed Central

Despite recent advances in therapeutic and diagnostic approaches, coronary artery disease (CAD) and its related cardiac disorders represent the most common cause of death in the United States. Nuclear myocardial perfusion imaging (MPI) technologies play a pivotal role in the diagnosis and treatment design for CAD. Recently, in order to develop improved MPI agents for diagnosis of CAD, 99mTc-[bis(dimethoxypropylphosphinoethyl)-ethoxyethyl-amine(PNP5)]-[bis(N-ethoxyethyl)dithiocarbamato(DBODC)]nitride(N-DBODC5)(99mTc-N-DBODC5) with a faster liver clearance than conventional single-photon emission computed tomography (SPECT) imaging agents (technetium 99m sestamibi (99mTc-MIBI) or technetium 99m tetrofosmin) has been introduced. In preclinical and phase I studies, 99mTc-N-DBODC5 has shown characteristics of an essentially ideal MPI tracer. Importantly, however, there is no data to support the use of 99mTc-N-DBODC5 to evaluate myocardial ischemia in patients with suspected CAD. The present study was designed to assess the clinical value of this agent; the findings of stress and rest MPI after the administration of this agent were compared to those of stress and rest 99mTc-MIBI, as well as those of coronary angiography, with respect to the detection of CAD. Our findings indicated the usefulness of 99mTc-N-DBODC5 as a promising MPI agent.

Ma, Haiyan; Li, Sijin; Wu, Zhifang; Liu, Jianzhong; Liu, Haiyan; Guo, Xiaoshan

2013-01-01

271

Electrical Generation  

NSDL National Science Digital Library

This short page is a concise presentation of how electricity can be generated. Hotlinks to circuits and current electricity are embedded. The left navigation bar includes links to Energy and Work, Potential and Kinetic Energy, Types of Energy, Atoms, Circuits, and Electrical Generation.

2004-01-01

272

Pattern generation  

Microsoft Academic Search

Central pattern generators are neuronal ensembles capable of producing the basic spatiotemporal patterns underlying ‘automatic’ movements (e.g. locomotion, respiration, swallowing and defense reactions), in the absence of peripheral feedback. Different experimental approaches, from classical electrophysiological and pharmacological methods to molecular and genetic ones, have been used to understand the cellular and synaptic bases of central pattern generator organization and reconfiguration

Yuri I Arshavsky; Tatiana G Deliagina; Grigori N Orlovsky

1997-01-01

273

Toxicity of sup 99 Tc: Can it represent a risk to man  

SciTech Connect

The movement through the environment and the toxicity to plants of {sup 99}Tc have been studied. However, information is scanty on {sup 99}Tc toxicity to mammals even though this is the decisive criterion for assessing the consequences of releases of Tc. A critical tissue could be the thyroid because of its preferential accumulation of Tc and the developing organism because of its greater radiosensitivity; moreover, this toxicity might be enhanced under conditions of a low iodine (I) diet. These questions were studied in rats given large amounts of {sup 99}Tc in either a normal or an I-deficient diet for several months starting 2 wk before mating. Newborns were continued on these diets after weaning. The parameters determined were: occurrence of pregnancy and litter size, triiodothyronine and thyroxin in serum, uptake of {sup 131}I by the thyroid 24 h after injection, histology of the thyroid and concentration of Tc in tissues of the mothers and their decendants. Thyroid damage, as well as the effects on pregnancy, could be observed after amounts of 10 micrograms Tc g-1 food. Iodine deficiency only slightly influences the {sup 99}Tc toxicity. The chemical and radiological toxicity of {sup 99}Tc to rats is small. Consequently, it seems unlikely that contamination levels in the environment would ever reach levels that could lead to serious non-stochastic effects, even in the developing organism.

Gerber, G.B.; Hegela, M.; Vankerkom, J.; Kirchmann, R.; Maisin, J.R.; Lambiet-Collier, M. (Centre d'Etude de l'Energie Nucleaire CEN-SCK (Belgium))

1989-08-01

274

Effect of cuprous ion on labeling of three skeletal imaging agents with 99m Tc  

Microsoft Academic Search

The effect of increased content of copper on the radiochemical composition of three skeletal imaging agents:99mTc(Sn)-methylene diphosphonate (MDP),99mTc(Sn)-pyrophosphate (PYP) and99mTc(Sn)-2,3-dicarboxypropane-1, 1-diphosphonate (DPD) was observed only in the case of99mTc(Sn)-MDP. It was found that the radiochemical purity of this radiopharmaceutical falls to about 50% when the copper content reaches about 10–5 mol dm–3. According to the results of radiochemical and biological

J. Vu?ina; D. Vuga; T. Maksin; N. Vanli?-Razumeni?

1994-01-01

275

Pentachlorooxotechnetate(VI) anion, (TcOCl/sub 5/): an EPR study  

SciTech Connect

The anion pentachlorooxotechnetate(VI), TcOCl/sub 5//sup -/, has been prepared by reduction of TcO/sub 4//sup -/ with HCl in concentrated H/sub 2/SO/sub 4/ and investigated by means of the EPR technique. The axial symmetric spectrum suggests an in-plane ..pi..-type ground state of the MO of the unpaired electron. The Tc-Cl/sub eq/ bonding properties have been discussed in terms of MO theory, and a comparison has been given to the bonding properties in likely complexes of neighboring elements of Tc.

Kirmse, R.; Stach, J.; Abram, U.

1985-07-03

276

[Quantification of separate renal function using Tc 99m DTPA and Tc 99m DMSA. Correlations between individual isotopic data and creatinine clearance].  

PubMed

The purpose of this prospective study (30 controls and 100 renal patients) is to compare one to each other the values of renal function measured with: 1--the DTPA 99mTc , 2--the DMSA 99mTc , and 3--the creatinine clearance. After the control values being established, correlations are done for the whole group (n = 130) between the creatinine clearance, the DTPA 99mTc clearance and the fixation rate of the DMSA 99mTc . The correlations obtained are:--Clcr Versus Cldtpa = 0,91.--Clcr Versus % Dmsa = 0,90. - Cldtpa Versus % Dmsa = 0,93. and indicate the two isotopic tests performed give similar quantitative results than creatinine clearance. Camera and computer allow to measure the separate renal function one by one, the two isotopic test giving similar values for each kidney. The results of these studies give a good concordance with the observed diseases, except for partial renal artery stenosis. The pyelic retention of DMSA 99mTc product, in condition of ureteral compression, gives a potential overestimation of this test and is a matter to debate. The extreme simplicity and facility of DMSA 99mTc procedures make this investigation accessible to any patient and give excellent morphological and functional tests. DTPA 99mTc clearances--global and separate kidney--give a more sensitive approach than DMSA 99mTc does because vascular captation , elimination rates could be focused. DTPA 99mTc procedure is to be used in patients with transplanted kidney, silent IVP kidney, contrast media contraindication or for exploring glomerular clearance without urine collection. PMID:6328339

Chevet, D; Moisan, A; Le Pogamp, P; Le Cloirec, J; Wehbe, B; Herry, J Y

1984-01-01

277

Studies of the retention mechanism of the brain perfusion imaging agent {sup 99m}{Tc}-bicisate ({sup 99m}{Tc}ECD)  

Microsoft Academic Search

The structure-activity relationship in a series of analogues of {sup 99m}{Tc}-bicisate ({sup 99m}{Tc}-N,Nā²-1,2-ethylene-diylbis-L-cysteine diethyl ester dihydrochloride, RP-217) is described using in vivo studies in rodent and primate brain tissue. All analogues investigated were {sup 99m}{Tc}-diamine dithiol diesters, which were neutral and lipophilic and had modified brain uptake indexes (ā„40) suggesting adequate first-pass extraction. All analogues were poorly retained by the

R. C. Walovitch; E. H. Cheesman; L. J. Maheu; K. M. Hall

1994-01-01

278

Brain Tumor Imaging with 99mTc-tetrofosmin: Comparison with 201Tl, 99mTc-MIBI, and 18F-fluorodeoxyglucose  

Microsoft Academic Search

The purpose of the present study was to assess the ability of technetium-99m-tetrofosmin (99mTc-TF) to predict tumor malignancy and to compare its uptake with that of thallium-201 (201Tl), technetium-99m-hexakis-2-methoxyisobutyl isonitrile (99mTc-MIBI) and fluorine-18-fluorodeoxyglucose (18F-FDG) in brain tumors. 99mTc-TF single-photon emission computed tomography (SPECT) imaging was performed in 22 patients with brain tumors and 3 healthy controls. Some of the patients

Joon Young Choi; Sang Eun Kim; Hyung Jin Shin; Byung-Tae Kim; Jong Hyun Kim

2000-01-01

279

Labelling of commercially available human serum albumin kits with 68Ga as surrogates for 99mTc-MAA microspheres.  

PubMed

An alternative method of labelling different commercially available human serum albumin kits with generator produced (68)Ga as possible surrogate markers for the investigation of the biodistribution, and to exclude a possible lung shunt in patients with solid primary tumours and liver metastases by positron emission-tomography (PET) and effective substitute for (99m)Tc HSA as a PET perfusion tracer is described. The radioactive labelling with (68)Ga was based on the elution of a commercial (68)Ge/(68)Ga generator system, which uses a modified tin dioxide column to absorb (68)Ga. We obtained (68)Ga-MAA and (68)Ga-HSA in radiochemical yields of 79 ± 5% with less than 5% free (68)Ga. The whole procedure takes a total of less than 30 min from elution to the final product. PMID:20880714

Maus, Stephan; Buchholz, Hans-Georg; Ament, Stephan; Brochhausen, Christoph; Bausbacher, Nicole; Schreckenberger, Mathias

2010-09-18

280

Power Systems Development Facility Gasification Test Run TC11  

SciTech Connect

This report discusses Test Campaign TC11 of the Kellogg Brown & Root, Inc. (KBR) Transport Gasifier train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The Transport Gasifier is an advanced circulating fluidized-bed gasifier designed to operate as either a combustor or a gasifier in air- or oxygen-blown mode of operation using a particulate control device (PCD). Test run TC11 began on April 7, 2003, with startup of the main air compressor and the lighting of the gasifier start-up burner. The Transport Gasifier operated until April 18, 2003, when a gasifier upset forced the termination of the test run. Over the course of the entire test run, gasifier temperatures varied between 1,650 and 1,800 F at pressures from 160 to 200 psig during air-blown operations and around 135 psig during enriched-air operations. Due to a restriction in the oxygen-fed lower mixing zone (LMZ), the majority of the test run featured air-blown operations.

Southern Company Services

2003-04-30

281

An Overview of ER-2 Platform Science during TC4  

NASA Astrophysics Data System (ADS)

The NASA high-altitude ER-2 aircraft flew 11 science flight out of San Jose, Costa Rica during July and August 2007 as part of the NASA-sponsored Tropical Composition, Clouds and Climate Coupling Experiment (TC4). The ER-2 flew a remote sensing payload consisting of passive optical and microwave imagers (MAS/MASTER, CoSSIR, AMPR), a high spectral resolution IR imager (S-HIS), active sensors (CPL lidar, CRS and EDOP radars), spectral solar (SSFR) and IR flux radiometers, a microwave temperature profiler (MTP), and a visible video camera (MVIS). This suite of sensors provided a high spatial resolution simulator for cloud, aerosol, sounding, and trace gas retrieval capabilities from the "A-Train" constellation, in particular, the Aqua, CloudSat, and CALIPSO satellites. In this talk we present an overview of the ER-2 TC4 science and validation objectives, and a summary of the campaign accomplishments. Science goals included observations of convective system development, anvil cirrus property evolution (i.e., microphysics, optical properties, narrow and broadband radiative fluxes), tropical Tropopause Transition Layer (TTL) and subvisual cirrus detection and characterization, marine boundary layer cloud properties, aerosol transport and optical properties, and trace gas and atmospheric state characteristics. Coordination with the DC-8 and/or WB-57 aircrafts allowed for validation of various retrievals from these observations. Morning flights (due to adverse local afternoon weather conditions) included coordination with the Terra spacecraft when feasible.

Platnick, S.; Newman, P. A.

2007-12-01

282

Thermal conductivity of impurity-doped high-Tc superconductors  

NASA Astrophysics Data System (ADS)

The thermal conductivity K(T) of polycrystalline YBa2(Cu1-xNx)3O7 with N=Zn and Al (0 <=x<=0.1) and Y1-yMyBa2Cu3O7 with M=Pr and Gd (0<=y<=1.0) has been measured for temperatures 1 .2<=T<=200 K. In the undoped samples, K(T) decreases slightly with decreasing temperature above Tc, with a strong enhancement of K(T) below Tc reaching a maximum at ~50 K followed by a sharp decrease. Doping with Zn and Pr, which have been shown to dramatically disturb the superconductivity, rapidly depresses the maximum in K(T) even at concentrations that remain superconducting. This effect is not as dramatic for Al- and Gd-doped samples, which do not strongly depress the superconductivity. These data are discussed considering both phonon and electron thermal conduction mechanisms, and are compared with relevant theories, such as a modified BRT theory of phonon conduction within the superconducting state.

Ting, S. T.; Pernambuco-Wise, P.; Crow, J. E.

1993-05-01

283

Thinking generations.  

PubMed

Often, and increasingly, social and political life is narrated using the concept of generation. This article looks at contemporary expressions of 'generationalism' in British public life. It identifies the salient themes which emerge, links these to the social and political contexts in which these ideas are produced, and examines the points where they are vulnerable to critique. Bridging science and normativity, the generational view offers a convenient master-narrative for a variety of political orientations - yet one whose democratic credentials are doubtful. PMID:23713557

White, Jonathan

2013-06-01

284

Thermomagnetic generator  

NASA Astrophysics Data System (ADS)

Cycles for producing electricity from heat utilizing the magnetocaloric effect are considered. A thermomagnetic generator producing electricity directly without a mechanical interface is studied analytically, with emphasis on low temperature (below 400 K) applications. Power density and efficiency higher than previously reported in the literature appear achievable. Areas for future investigation include identification of optimum materials and verification of heat transfer correlations. Capital cost for a thermomagnetic generator is comparable to the cost for commercially available low temperature, organic Rankine cycle generators. Cycles utilizing chemical reactions to change magnetic properties are also considered.

Kirol, L.; Mills, J.; Vanhaaften, D.

1983-11-01

285

Energy generator  

SciTech Connect

The patent describes a power booster. It comprises: at least one pendulum means suspended at one end to oscillate about the point of suspension; power generating means; mass means connected to one end of the pendulum means; spring means disposed in operative cooperation with the mass means to impart energy into the pendulum means and assist the pendulum means in oscillating about the point of suspension; and energy transfer linkage means between the pendulum means and the power generating means for transferring energy between the pendulum means and the power generating means.

Krisko, P.

1989-08-01

286

Radiosynthesis and biological evolution of 99m Tc(CO) 3 –sitafloxacin dithiocarbamate complex: a promising Staphylococcus aureus infection radiotracer  

Microsoft Academic Search

Radio-complexation of sitafloxacin dithiocarbamate (SFDE) with technetium-99m (99mTc) using [99mTc(OH2)3(CO)3]+ precursor was investigated and compared with the 99mTc labeled SFDE prepared through 99mTcN core. The 99mTc(CO)3–SFDE radiocomlpex was assessed in terms of radiochemical purity (RCP), eternalness in serum, in vitro binding with Staphylococcus aureus (S. aureus) and biodistribution in artificially Staphylococcus aureus infected rats (SAIR). The feasibility of the 99mTc(CO)3–SFDE

Syed Qaiser Shah; Aakif Ullah Khan; Muhammad Rafiullah Khan

2011-01-01

287

Nuclear shape and structure in neutron-rich 110,111Tc  

SciTech Connect

The structure of Tc nuclei is extended to the moreneutron-rich regions based on measurements of prompt gamma rays from thespontaneous fission of 252Cf at Gammasphere. The level scheme of N=67neutron-rich (Z=43) 110Tc is established for the first time and that of111Tc is expanded. The ground-state band of 111Tc reaches theband-crossing region and the new observation of the weakly populatedalpha = -1/2 member of the band provides important information ofsignature splitting. The systematics of band crossings in the isotopicand isotonic chains and a CSM calculation suggest that the band crossingof the gs band of 111Tc is due to alignment of a pair of h11/2 neutrons.The best fit to signature splitting, branching ratios, and excitations ofthe ground-state band of 111Tc by RTRP model calculations result in ashape of epsilon2 = 0.32 and gamma = -26 deg. for this nucleus. Itstriaxiality is larger than that of 107Tc, to indicate increasingtriaxiality with increasing neutron number. The identification of theweakly-populated "K+2 satellite" band provides strong evidence for thelarge triaxiality of 111Tc. In 110Tc the four lowest-lying levelsobserved are very similar to those in 108Tc. At an excitation of 478.9keV above the lowest state observed, ten states of a delta I = 1 band areobserved. This band is very analogous to the delta I = 1 bands in106,108Tc, but it has greater signature splitting at higherspins.

Luo, Y.X.; Hamilton, J.H.; Rasmussen, J.O.; Ramayya, A.V.; Stefanescu, I.; Hwang, J.K.; Zhu, S.J.; Gore, P.M.; Jones, E.F.; Fong,D.; Wu, S.C.; Lee, I.Y.; Ginter, T.N.; Ter-Akopian, G.M.; Daniel, A.V.; Stoyer, M.A.; Donangelo, R.; Gelberg, A.

2006-02-02

288

Vibration generators  

SciTech Connect

Apparatus for generating vibrations in a medium, such as the ground, comprises a first member which contacts the medium, means , preferably electromagnetic, which includes two relatively movable members for generating vibrations in the apparatus and means operatively connecting the said two members to said first member such that the relatively amplitudes of the movements of said three members can be adjusted to match the impedances of the apparatus and the medium.

Lerwill, W.E.

1980-09-16

289

Plasma Generation  

Microsoft Academic Search

\\u000a Lightnings and technical plasmas are generated by an electric breakdown in a gas. The ignition process leads to a subsequent\\u000a current flow that generates an electrical discharge. Depending on the power source that feeds the plasma, we distinguish direct\\u000a current (dc), low-frequency alternating current (ac), and radio-frequency (rf) discharges. This chapter gives a brief introduction\\u000a into the most common types

Alexander Piel

290

Glomerular filtration rate in children: validation and longitudinal use of determination from the 99mTc DTPA renogram  

SciTech Connect

The glomerular filtration rate (GFR) was estimated from the technetium diethylenetriaminepentacetic (/sup 99m/Tc DTPA) renogram by empirically correlating the renogram and clearance of the tracer as measured by plasma disappearance kinetics. To expand the potential application of this technique from its original description, minor changes in methodology were made; a new regression was generated with 30 subjects, and that formula was then validated prospectively. For the 50 children and adolescents in the prospective series whose GFR normalized for surface area (NGFR = GFR X 1.73 m2/SA; SA, surface area) was less than 120 mL/min/1.73 m2; renal function was estimated with a mean residual error of 8.0 mL/min/1.73 m2, and a mean relative error of 11%. These results are at least as good as those in the initial report, thus validating this method in a prospective series. To examine the use of this method longitudinally, 129 examinations were reviewed in 55 subjects who had NGFR estimated from the renogram (estimated) on at least two occasions. For 28 sets of serial examinations, NGFR was also measured by the plasma disappearance of /sup 99m/Tc DTPA (measured). The true change in function for each set of serial examinations was defined as the increment for whichever method (estimation or measurement) was more stable. The mean longitudinal errors were 2.1 and 4.8 mL/min/1.73 m2 for measured and estimated NGFR, respectively. The increments in NGFR for these methods were correlated with a regression line near identity and r = .852. This indicates that a change in estimated NGFR reflects a change in measured NGFR of similar magnitude. This method can accurately estimate GFR from the /sup 99m/Tc DTPA renogram, and it can be used longitudinally to follow children with renal disorders.

Shore, R.M.; Koff, S.A.; Hayes, J.R.; Smith, S.P.; Mentser, M.; Mahan, J.D.

1986-09-01

291

Window generator  

NASA Astrophysics Data System (ADS)

The present invention relates generally to video target recognition systems and more specifically to a window generator which receives a field of video data and applies an identification code to rectangular subregions to identify distinct target areas within a given background area. The present invention comprises a window generator which provides a 6 bit target identification number for up to 63 target areas and one background area in a frame of serially scanned data. The window generator receives a field of video data from an image data source. This video data consists of digitized frames of serially scanned data similar to a conventional television screen image, which is divided horizontally in pixels, and vertically in lines. The window generator permits any given frame to be subdivided into specific rectangular subregions, which may be located anywhere on the video picture. By allowing statistics to be collected on the individual subregions (or target areas) the window generator permits local processing of video data within the specified target areas as opposed to processing of video data over the entire video field. One embodiment of the window generator is composed of: a microprocessor, a random access memory (RAM), a comparator, a line memory, two counters, an OR gate, a frame initialization circuit, and a buffer. These elements function as described below.

Johnson, William K.; May, Roger A.

1989-03-01

292

Synthesis and characterization of technetium(III) complexes with nitrogen heterocycles by O atom transfer from oxotechnetium(V) cores. Crystal structures of mer-(Cl sub 3 (pic) sub 3 Tc) and mer-(Cl sub 3 (pic)(PMe sub 2 Ph) sub 2 Tc) (pic = 4-picoline). Electrochemical parameters fore the reduction of Tc sup II , Tc sup III , and Tc sup IV  

Microsoft Academic Search

The combination of pyridine ligands, (OClāTc)ā», and O atom acceptors of different cone angles, such as PMeāPh or PPhā, results in Tc{sup III} complexes that vary in the coordination of the phosphine ligand. The compounds mer(Clā(4-picoline)āTc) and mer-(Clā(4-picoline)(PMeāPh)āTc) have been obtained in good yield and have been characterized spectroscopically and by single-crystal x-ray diffraction. The crystal structure data are reported.

Jun Lu; Akahito Yamano; M. J. Clarke

1990-01-01

293

Synthesis, structure elucidation and redox properties of 99Tc complexes of lacunary Wells Dawson polyoxometalates: insights into molecular 99Tc - metal oxide interactions  

SciTech Connect

The isotope 99Tc (beta max: 250 keV, half-life: 2 x 105 year) is an abundant product of uranium-235 fission in nuclear reactors and is present throughout the radioactive waste stored in underground tanks at Hanford and Savannah River. Understanding and controlling the extensive redox chemistry of 99Tc is important to identify tunable strategies to separate 99Tc from spent fuel and from waste tanks and once separated, to identify and develop an appropriately stable waste-form for 99Tc. Polyoxometalates (POMs), nanometer sized models for metal oxide solid-state materials, are used in this study to provide a molecular level understanding of the speciation and redox chemistry of incorporated 99Tc. In this study, 99Tc complexes of the (alpha 2-P2W17O61)10- and (alpha 1-P2W17O61)10- isomers were prepared. Ethylene glycol was used as a"transfer ligand" to minimize the formation of TcO2 cdot xH2O. The solution structures, formulations, and purity of TcVO(alpha 1/alpha 2-P2W17O61)7- were determined by multinuclear NMR. X-ray Absorption Spectroscopy of the complexes are in agreement with the formulation and structures determined from 31P and 183W NMR. Preliminary electrochemistry results are consistent with the EXAFS results, showing a facile reduction of the TcVO(alpha 1-P2W17O61)7- species compared to the TcVO(alpha 2-P2W17O61)7- analog. The alpha1- defect is unique in that a basic oxygen atom is positioned toward the alpha1- site and the TcVO center appears to form a dative metal-metal bond with a framework W site. These attributes may lead to the assistance of protonation events that facilitate reduction. Electrochemistry comparison shows that the ReV analogs are about 200 mV more difficult to reduce in accordance with periodic trends.

McGregor, Donna; Burton-Pye, Benjamin P.; Howell, Robertha C.; Mbomekalle, Israel M.; Lukens Jr, Wayne W.; Bian, Fang; Mausolf, Edward; Poineau, Frederic; Czerwinski, Kenneth R; Francesconi, Lynn C.

2011-01-10

294

Synthesis, structure elucidation, and redox properties of 99Tc complexes of lacunary Wells-Dawson polyoxometalates: insights into molecular 99Tc-metal oxide interactions.  

PubMed

The isotope (99)Tc (?(max), 293.7; half-life, 2.1 × 10(5) years) is an abundant product of uranium-235 fission in nuclear reactors and is present throughout the radioactive waste stored in underground tanks at the Hanford and Savannah River sites. Understanding and controlling the extensive redox chemistry of (99)Tc is important in identifying tunable strategies to separate (99)Tc from spent fuel and from waste tanks and, once separated, to identify and develop an appropriately stable waste form for (99)Tc. Polyoxometalates (POMs), nanometer-sized models for metal oxide solid-state materials, are used in this study to provide a molecular level understanding of the speciation and redox chemistry of incorporated (99)Tc. In this study, (99)Tc complexes of the (?(2)-P(2)W(17)O(61))(10-) and (?(1)-P(2)W(17)O(61))(10-) isomers were prepared. Ethylene glycol was used as a "transfer ligand" to minimize the formation of TcO(2)·xH(2)O. The solution structures, formulations, and purity of Tc(V)O(?(1)/?(2)-P(2)W(17)O(61))(7-) were determined by multinuclear NMR. X-ray absorption spectroscopy of the complexes is in agreement with the formulation and structures determined from (31)P and (183)W NMR. Preliminary electrochemistry results are consistent with the EXAFS results, showing a facile reduction of the Tc(V)O(?(1)-P(2)W(17)O(61))(7-) species compared to the Tc(V)O(?(2)-P(2)W(17)O(61))(7-) analog. The ?(1) defect is unique in that a basic oxygen atom is positioned toward the ?(1) site, and the Tc(V)O center appears to form a dative metal-metal bond with a framework W site. These attributes may lead to the assistance of protonation events that facilitate reduction. Electrochemistry comparison shows that the Re(V) analogs are about 200 mV more difficult to reduce in accordance with periodic trends. PMID:21268605

McGregor, Donna; Burton-Pye, Benjamin P; Howell, Robertha C; Mbomekalle, Israel M; Lukens, Wayne W; Bian, Fang; Mausolf, Edward; Poineau, Frederic; Czerwinski, Kenneth R; Francesconi, Lynn C

2011-01-26

295

Studies on chemical effects on x-ray intensity ratios of K\\/sub. beta. \\/\\/K\\/sub. cap alpha. \\/ in nuclear decay of technetium nuclides \\/sup 99m\\/Tc, \\/sup 97m\\/Tc, and \\/sup 95m\\/Tc  

Microsoft Academic Search

Chemical effects of characteristic x-ray intensity ratios of K\\/sub ..beta..\\/\\/K\\/sub ..cap alpha..\\/ were investigated for the second d-group element Tc in the decay processes \\/sup 99m\\/Tc ..-->.. ā¹ā¹Tc (two-step isomeric transition), \\/sup 97m\\/Tc ..-->.. ā¹ā·Tc (one-step isomeric transition), and \\/sup 95m\\/Tc ..-->.. ā¹āµMo (electron capture). The objective nuclides were produced by (n, ..gamma..)..beta..ā», (d, xn), and (..cap alpha.., xn) reactions

I. Yamoto; H. Kaji; K. Yoshihara

1986-01-01

296

Evaluation of residual functional lung volume on Tc-99m DTPA aerosol ventilation and Tc-99m MAA perfusion scintigraphy in primary ciliary dyskinesia (Kartagener syndrome).  

PubMed

Kartagener syndrome is diagnosed as sinusitis, bronchitis (bronchiectasis), and situs inversus by the clinical features. It is a subclass of primary ciliary dyskinesia (PCD) disease. A 12-year-old girl who had frequent upper and lower airway infections since birth, which was confirmed as Kartagener syndrome by HRCT imaging. We present the residual functional lung volume and mucociliary clearance findings seen on Tc-99m DTPA aerosol ventilation and Tc-99m MAA perfusion scintigraphy. PMID:19033804

Chen, Yu-Wen; Chang, Chin-Chuan; Lai, Yung-Chuang; Lu, Chia-Ying; Dai, Zen-Kong

2008-12-01

297

A micro-autoradiographical study of the localization of 99m Tc(Sn)MDP and 99m TcMDP in undecalcified bone sections  

Microsoft Academic Search

The localization of 99mTc(Sn)-MDP in bone tissue was compared with 99mTc-MDP by means of microautoradiography of undecalcified bone sections. Sections of good histological quality were obtained by a rapid embedding method in methylmethacrylate. No differences were found in the localization of these radiopharmaceuticals in fetal rat calvariae after incubation in vitro or in rat femora after administration in vivo. In

T. Jean F. Savelkoul; Walter J. Visser; Siwart J. Oldenburg; Sijmen A. Duursma

1986-01-01

298

Massively parallel sequencing reveals the complex structure of an irradiated human chromosome on a mouse background in the Tc1 model of Down syndrome.  

PubMed

Down syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and presents a complex phenotype that arises from abnormal dosage of genes on this chromosome. However, the individual dosage-sensitive genes underlying each phenotype remain largely unknown. To help dissect genotype--phenotype correlations in this complex syndrome, the first fully transchromosomic mouse model, the Tc1 mouse, which carries a copy of human chromosome 21 was produced in 2005. The Tc1 strain is trisomic for the majority of genes that cause phenotypes associated with DS, and this freely available mouse strain has become used widely to study DS, the effects of gene dosage abnormalities, and the effect on the basic biology of cells when a mouse carries a freely segregating human chromosome. Tc1 mice were created by a process that included irradiation microcell-mediated chromosome transfer of Hsa21 into recipient mouse embryonic stem cells. Here, the combination of next generation sequencing, array-CGH and fluorescence in situ hybridization technologies has enabled us to identify unsuspected rearrangements of Hsa21 in this mouse model; revealing one deletion, six duplications and more than 25 de novo structural rearrangements. Our study is not only essential for informing functional studies of the Tc1 mouse but also (1) presents for the first time a detailed sequence analysis of the effects of gamma radiation on an entire human chromosome, which gives some mechanistic insight into the effects of radiation damage on DNA, and (2) overcomes specific technical difficulties of assaying a human chromosome on a mouse background where highly conserved sequences may confound the analysis. Sequence data generated in this study is deposited in the ENA database, Study Accession number: ERP000439. PMID:23596509

Gribble, Susan M; Wiseman, Frances K; Clayton, Stephen; Prigmore, Elena; Langley, Elizabeth; Yang, Fengtang; Maguire, Sean; Fu, Beiyuan; Rajan, Diana; Sheppard, Olivia; Scott, Carol; Hauser, Heidi; Stephens, Philip J; Stebbings, Lucy A; Ng, Bee Ling; Fitzgerald, Tomas; Quail, Michael A; Banerjee, Ruby; Rothkamm, Kai; Tybulewicz, Victor L J; Fisher, Elizabeth M C; Carter, Nigel P

2013-04-15

299

Massively Parallel Sequencing Reveals the Complex Structure of an Irradiated Human Chromosome on a Mouse Background in the Tc1 Model of Down Syndrome  

PubMed Central

Down syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and presents a complex phenotype that arises from abnormal dosage of genes on this chromosome. However, the individual dosage-sensitive genes underlying each phenotype remain largely unknown. To help dissect genotype – phenotype correlations in this complex syndrome, the first fully transchromosomic mouse model, the Tc1 mouse, which carries a copy of human chromosome 21 was produced in 2005. The Tc1 strain is trisomic for the majority of genes that cause phenotypes associated with DS, and this freely available mouse strain has become used widely to study DS, the effects of gene dosage abnormalities, and the effect on the basic biology of cells when a mouse carries a freely segregating human chromosome. Tc1 mice were created by a process that included irradiation microcell-mediated chromosome transfer of Hsa21 into recipient mouse embryonic stem cells. Here, the combination of next generation sequencing, array-CGH and fluorescence in situ hybridization technologies has enabled us to identify unsuspected rearrangements of Hsa21 in this mouse model; revealing one deletion, six duplications and more than 25 de novo structural rearrangements. Our study is not only essential for informing functional studies of the Tc1 mouse but also (1) presents for the first time a detailed sequence analysis of the effects of gamma radiation on an entire human chromosome, which gives some mechanistic insight into the effects of radiation damage on DNA, and (2) overcomes specific technical difficulties of assaying a human chromosome on a mouse background where highly conserved sequences may confound the analysis. Sequence data generated in this study is deposited in the ENA database, Study Accession number: ERP000439.

Clayton, Stephen; Prigmore, Elena; Langley, Elizabeth; Yang, Fengtang; Maguire, Sean; Fu, Beiyuan; Rajan, Diana; Sheppard, Olivia; Scott, Carol; Hauser, Heidi; Stephens, Philip J.; Stebbings, Lucy A.; Ng, Bee Ling; Fitzgerald, Tomas; Quail, Michael A.; Banerjee, Ruby; Rothkamm, Kai; Tybulewicz, Victor L. J.; Fisher, Elizabeth M. C.; Carter, Nigel P.

2013-01-01

300

Hydrometeor Trajectories and Distributions in a Simulation of TC Rapid Intensification (RI)  

NASA Astrophysics Data System (ADS)

It has long been recognized that the microphysics scheme used in a numerical simulation of tropical cyclones (TC) can greatly affect the precipitation distribution, intensity and thermodynamic structure of the simulated TC. This suggests that the mixing ratios, concentrations and size distributions of hydrometeor(snow, graupel,rain,cloud ice) are important factors in the evolution of TC . The transport of hydrometeor may have a strong influence on these factors through its interactions with the growth and the latent heat forcing of hydrometeor and the wind filed, hence is a key to understanding TC microphysics. Schematic hydrometeor trajectories were first constructed using 3-D wind field and particle fallspeeds derived from airborne radar observations in a steady-state mature hurricane,Alicia(1983). Since then, little effort has been put in understanding hydrometeor transport in TC, especially the potential link between its evolution and the intensity and structure changes in a non-steady-state TC. This study is focused on investigating such a link by means of numerical simulations of TC Rapid Intensification(RI) using WRF model. We use the tracer utility in WRF to construct hydrometeor trajectories. Most of the popular microphysics schemes are tested, and the most reasonable test( which is determined by comparing the simulated TC intensity and structure with airborne radar observations) and the ensemble mean of all the tests are picked for detailed examinations.

Zhu, Z.; Zhu, P.

2010-12-01

301

Magnetic texture driven charge pairing in high-Tc superconducting cuprates  

Microsoft Academic Search

We propose a model for high-Tc cuprates that considers hole fractionalization into charge, associated to magnetic texture (skyrmion) excitations of the Cu spin background, and spin, represented by chargeless fermion excitations. The superconducting transition occurs when the effective potential between skyrmions allows for skyrmion bound states and this is expressed as an algebraic equation for Tc as a function of

Eduardo C. Marino; Marcello B. Silva Neto

2004-01-01

302

Preparation of (99m)tc-clomiphene citrate as a novel agent for breast cancer imaging.  

PubMed

The aim of this work was to develop a novel (99m)Tc-labelled derivative based on triphenylethylene for breast cancer imaging. (99m)Tc-Clomiphene was obtained with a radiochemical yield of 94.4% by adding (99m)Tc to 1.5?mg Clomiphene citrate in the presence of 10??g SnCl(2) at pH 7. The optimization of the labeling yield of Clomiphene citrate, with (99m)Tc, is described. The reaction parameters that affect the labeling yield were studied to optimize the labeling conditions. Radiochemical purity of the final product has been verified by means of paper chromatography and paper electrophoresis. Ehrlich Ascites Carcinoma (EAC) as a model of breast cancer cells was injected intraperitoneally (IP) to produce ascites and intramuscularly (IM) to produce solid tumor. Biodistribution study was carried out by the injecting solution of (99m)Tc-Clomiphene in normal and tumor bearing mice. The uptake in ascites was over 12.5 % injected dose per gram tissue body weight, at 1hr after injection and above 12% in solid tumor. The T/NT value for (99m)Tc-Clomiphene complex was found to be 5.5 ± 0.4 which was higher than that of the commercially available (99m)Tc-MIBI. This data revealed the localization of tracer in tumor tissue with high percent sufficient to use (99m)Tc-Clomiphene as a promising tool for the diagnosis of breast cancer. PMID:23213567

Ibrahim, Ismail Taha; Elkolally, Mohamed Taha; Abd Elgany, Ibrahim Yousof; Abd Albary, Ahmed; Hodhod Elsayed, Mohamed

2012-11-14

303

Charge transfer and carrier density in Bi2212 high-Tc superconductors  

Microsoft Academic Search

Muon spin relaxation and neutron diffraction measurements were performed in Y and Pb substituted Bi-2212 superconductors in order to study the correlation between Tc and hole density. We observe first an increase of both Tc and the superconducting carrier density via hole transfer, but subsequently (at higher ``doping'') more and more holes are prevented from forming superconducting pairs.

H. Maletta; M. Weber; A. Amato; J. Bock; V. N. Duginov; V. G. Grebinnik; F. N. Gygax; S. Kapusta; B. F. Kirillov; V. G. Olshevsky; A. V. Pirogov; Y. Yu. Pomjakushin; A. N. Ponomarev; E. Preisler; A. Schenck; V. G. Storchak; V. A. Zhukov

1992-01-01

304

Radiation exposure due to 99m Tc and 131 I manipulated in syringes  

Microsoft Academic Search

Dose rates around and at the surface of disposable polypropylene syringes of 1 and 2 ml volume filled with 99mTc and 131I solutions were determined by thermoluminescence dosimetry. Data for the efficacy of 0.5 and 1 mm lead shielding of 99mTc and for the dose contribution due to ß- -radiation from 131I are given.

W. Schmidt; R. Nowotny; K. Kletter; H. Frischauf

1979-01-01

305

Double Star TC1 observations of component reconnection at the dayside magnetopause: a preliminary study  

Microsoft Academic Search

In spring 2004 Double Star TC-1 measured a number of reconnection signatures at the dayside low-latitude magnetopause (MP) when there was a notable By component in the magnetosheath. In a number of events we can show that reconnection was operating nearby TC-1 in the subsolar MP region. In this paper we describe three representative events: (a) event on 21 March

Z. Y. Pu; C. J. Xiao; X. G. Zhang; Z. Y. Huang; S. Y. Fu; Z. X. Liu; M. W. Dunlop; Q. G. Zong; C. M. Carr; H. Réme; I. Dandouras; A. Fazakerley; T. Phan; T. L. Zhang; H. Zhang; X. G. Wang

2005-01-01

306

Impact of Mobile-Immoble Water on the Transport of Technetium (Tc99) in Unsaturated Sediments  

Microsoft Academic Search

Technetium has been released to the environment through nuclear power production and nuclear fuel processing; as a result, further spreading of Tc-99 is a concern at DOE sites across the US. The current body of work conducted on Tc-99 has provided a wealth of information regarding the redox relationships, sorption, solubility, and stability of the mineral phases, however little work

D. P. Jansik; D. M. Wellman; E. Cordova; D. Wildenschild

2010-01-01

307

Role of LO phonon on pseudo-gap phase in high-Tc cuprate superconductors  

Microsoft Academic Search

In analyzing the role of optical phonon on transition temperature Tc, the simplified extended BCS-like theory was tried in success and why Coulomb interaction must be large was understood. Oxygen (O) -isotope effect on Tc was explained in good agreement with more than 120 experimental data. The superconductivity appears in itself due to Bose-condensation of bipolarons coupled with surrounding local

Eiko Matsushita; Keigo Hirayama

2009-01-01

308

Family of Tc1-like elements from fish genomes and horizontal transfer  

Microsoft Academic Search

The involvement of horizontal transfer (HT) in the evolution of vertebrate transposable elements (TEs) is a matter of an ongoing debate. The phylogenetic relationships between Tc1 TEs, based on limited dataset have been previously used to infer a case of Tc1 HT between the genomes of fish and frogs. Here this hypothesis has been critically evaluated by the experimental approach

Anita Pocwierz-Kotus; Artur Burzynski; Roman Wenne

2007-01-01

309

A high-Tc flip-chip SQUID gradiometer for mobile underwater magnetic sensing  

Microsoft Academic Search

We report on the development of a magnetic gradient tensor sensor based on high- Tc SQUIDs for marine surveying applications. The proposed system uses six planar gradiometers incorporated into a hexagonal pyramid structure where the combined output will provide a measure of the gradient tensor. This report focuses on the development and characterization of long baseline high- Tc SQUID gradiometers

S. T. Keenan; J. A. Young; C. P. Foley; J. Du

2010-01-01

310

/sup 99m/Tc pertechnetate uptake in a thymoma: case report  

SciTech Connect

A case is reported to /sup 99m/Tc pertechnetate accumulation within an anterior mediastinal thymoma during a search for substernal goiter. This reemphasizes the non-specificity of /sup 99m/Tc pertechnetate uptake and the need for caution in using this agent to detect ectopic thyroid tissue.

Wilson, R.L.; Cowan, R.J.

1982-04-01

311

Sup 99 Tc bioassay by inductively coupled plasma mass spectrometry (ICP-MS).  

National Technical Information Service (NTIS)

A means of analyzing (sup 99)Tc in urine by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. Historically, (sup 99)Tc analysis was based on the radiometric detection of the 293 keV E(sub Max) beta decay product by liquid scintilla...

L. A. Lewis

1998-01-01

312

Diagnosing protein losing enteropathy: A new approach using Tc-99m human immunoglobulin  

SciTech Connect

Tc-99m HIG has recently come into prominence as an inflammation seeking radiotracer. The authors describe a novel use of the agent for imaging protein-losing enteropathy. The agent may have certain advantages over Tc-99m HSA, which is currently being used for imaging protein loss. 19 refs., 2 figs.

Bhatnagar, A.; Kashyap, R.; Chopra, M.K. [Institute of Nuclear Medicine and Allied Sciences, Delhi (India)] [and others

1995-11-01

313

Magnetic and thermal properties of high Tc superconductors  

SciTech Connect

Measurements of the normal state magnetic susceptibility {chi}(T) of YBa{sub 2}Cu{sub 3}O{sub 7}, Bi{sub 1.8}Pb{sub 0.2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}, and Bi{sub 2{minus}x}Pb{sub x}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+{delta}} (x = 0.2 and 0.25) were carried out. All {chi}(T) data show negative curvature below {approximately}2{Tc}. The data for YBa{sub 2}Cu{sub 3}O{sub 7} are in excellent agreement with a new calculation of the superconducting fluctuation diamagnetism. From the analysis, we infer s-wave pairing and microscopic parameters are obtained. For {chi}(T) of YBa{sub 2}Cu{sub 3}O{sub 7}, part of the negative curvature is inferred to arise from the normal state background. We find a strong temperature dependent anisotropy {delta}{chi} {equivalent to} {chi}{sub c} {minus} {chi}{sub ab} and estimate the normal state spin contributions to {chi}(T). The heat capacity C(T) of YBa{sub 2}Cu{sub 3}O{sub 7} is reported for 0.4 K < T < 400 K in zero and 70 kG magnetic fields. In addition to the feature associated with the onset of the superconductivity at {Tc}, two anomalies in C(T) were observed near 74 K and 330 K, with another possible anomaly near 102 K; the temperatures at which they occur correlate with anomalies in {chi}(T) and ultransonic measurements. The occurrence of the anomaly at {approx equal} 330 K is found to be sample-dependent. The influences of a magnetic field and the thermal and/or magnetic field treatment history dependence of a pellet sample on C(T), the entropy and the influence of superconducting fluctuations on C(T) near {Tc}, and the possible source of the observed intrinsic nonzero {gamma}(0) at low T are discussed.

Lee, Wonchoon.

1990-09-21

314

Work in progress: clinical evaluation of Tc-99m-trimethylbromo-IDA and Tc-99m-diisopropyl-IDA for hepatobiliary imaging  

SciTech Connect

Six healthy individuals and six patients with a wide range of hepatobiliary function abnormalities were studied with Tc-99m-trimethylbromo-IDA; all normal subjects and four of the six patients were also studied with Tc-99m-diisopropyl-IDA. Visual evaluation of analog images demonstrated a greater liver-to-kidney ratio for Tc-99m-trimethylbromo-IDA (p less than 0.01). Sampling for radiopharmaceutical in urine at three hours following injection demonstrated that Tc-99m-trimethylbromo-IDA had a lower renal excretion rate than Tc-99m-diisopropyl-IDA regardless of whether hepatocyte function was normal or abnormal (p less than 0.01). There were no significant differences between the two radiopharmaceuticals in hepatocyte extraction efficiency or hepatic parenchymal transit time. It is concluded that the lower rate of renal excretion and, therefore, greater hepatocyte specificity of Tc-99m-trimethylbromo-IDA justifies expanded clinical trials and may make it the radiopharmaceutical of choice for hepatobiliary imaging.

Klingensmith, W.C.; Fritzberg, A.R.; Spitzer, V.M.; Kuni, C.C.; Williamson, M.R.; Gerhold, J.P.

1983-01-01

315

Regional radioactivity discrepancy between Tc-99m GSA and Tc-99m phytate liver scans in a patient with massive hepatic necrosis.  

PubMed

A 22-year-old woman with severe acute hepatitis underwent a Tc-99m galactosyl human serum albumin (GSA) scan. Intense accumulation was observed in the cephalic region of the right hepatic lobe, whereas the accumulation was reduced in the left lobe and the caudal region of the right lobe. A computed tomographic (CT) scan showed that the left lobe and the caudal region of the right posterior segment had atrophied and become hypodense, which were thought to represent postnecrotic scarring after massive hepatic necrosis. The relatively hyperdense region in the right lobe was slightly swollen and was thought to represent regenerating liver tissue or a "potato liver." Compared with the CT, the regions of elevated Tc-99m GSA accumulation correlated well with the areas of regenerating liver tissue, and the regions with reduced accumulation corresponded closely with the areas of postnecrotic scarring. On a Tc-99m phytate scan, unlike the Tc-99m GSA scan, the radiocolloid accumulation was intense in the left lobe and caudal region of the right lobe and reduced in the cephalic region of the right lobe. Together, the Tc-99m GSA scan and the Tc-99m phytate scan formed a set of exact "nega-posi" images. Biopsy specimens obtained during laparoscopy showed a few hepatocyte columns in the postnecrotic scarred left lobe. Severe disruption of the hepatocytes, prominent inflammatory cell infiltration, and obvious Kupffer cell hypertrophy and clustering were also observed. PMID:12170005

Akaki, Shiro; Saeki, Mototsugu; Iguchi, Toshihiro; Okumura, Yoshihiro; Sato, Shuhei; Kuroda, Masahiro; Kanazawa, Susumu; Hiraki, Yoshio; Uraoka, Toshio; Baba, Nobuyuki; Sakaguchi, Kosaku

2002-08-01

316

CCMR: Kelvin Probe Microscopy for Investigation of Charge Ordering in High-Tc Superconductors  

NSDL National Science Digital Library

The major hurdle that stands between high-critical-temperature (high-Tc) superconductivity as an area of pure research and the harnessing of high-Tc superconducting materials for manageable ādissipation-lessā technologies is that we lack a comprehensive perception of all the mechanisms which govern high-Tc superconductivity. Controversial in nature, ācharge stripingā or charge ordering in superconducting transition metal oxides is arguably one of the mechanisms underlying high-Tc superconductivity. Here we introduce Kelvin Probe Force Microscopy (KPFM) and novel technologies utilizing carbon nanotubes (CNTs) as a means to resolve charge ordering in high-Tc superconducting materials. We also explore the limits of these technologies as charge-resolving tools.

Berg, Morgann

2007-08-29

317

The uptake of TcO-4 by plants: A mathematical description  

SciTech Connect

A model describing the uptake of TcO-4 by spinach plants was developed. The equation relates both plant and soil parameters (e.g., growth, metabolism, concentration of TcO-4 and composition of the growth medium) to the concentration of Tc in the shoot of the plant. As the soil solution is the medium from which plants obtain nutrients and non-nutrients, the modeling parameters have been obtained from uptake experiments using nutrient solutions (= simulated soil solutions) as the growth medium. Two important model assumptions are: (1) that an equilibrium exists between TcO-4 in the plant and the growth medium and (2) that the leaf TcO-4 metabolism is a pseudofirst order reaction occurring in a non-constant volume.

Van Loon, L.R.; Desmet, G.M.; Cremers, A. (RIVM, Laboratory of Radiation Research, Bilthoven (Netherlands))

1989-08-01

318

Collective band structures in neutron-rich {sup 106,107}Tc  

SciTech Connect

The high spin states of neutron-rich {sup 106,107}Tc nuclei have been reinvestigated by observing prompt {gamma} rays from the spontaneous fission of {sup 252}Cf. In {sup 106}Tc, a previously known collective band is expanded, and a new collective band is identified. In {sup 107}Tc, a collective band based on the {pi}5/2{sup -}[303] orbital is confirmed and extended. Inconsistencies in the configuration assignments for positive parity bands in {sup 105,107}Tc in the previous reports are clarified. The spins and parities as well as the configurations for the two bands in {sup 106}Tc are assigned according to the angular momentum alignments and g-factor calculations. Other characteristics for the observed bands are discussed.

Gu, L.; Wang, J. G.; Che, X. L.; Ding, H. B.; Xu, Q.; Yang, Y. Y. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhu, S. J. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Liu, S. H.; Li, K. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Luo, Y. X. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ma, W. C. [Department of Physics, Mississippi State University, Mississippi State, Mississippi 39762 (United States)

2009-05-15

319

Clearance of Tc-99m DTPA in hemodialysis and peritoneal dialysis: concise communication  

SciTech Connect

The clearance of Tc-99m DTPA was studied in 14 patients undergoing hemodialysis (HD) or peritoneal dialysis (PD). Mean Tc-99m DTPA clearance during HD was 37.8% +/- 10.1 of creatinine clearance. Mean Tc-99m DTPA clearance in PD was 65.1% +/- 10.3 of creatinine clearance. Tc-99m DTPA, with a larger molecular weight than that of creatinine, is cleared relatively better during PD than during HD. Thus Tc-99m DTPA may be used in the assessment of the effectiveness of different dialytic treatments for substances of similar molecular weight. In addition, our study shows that clearance of DTPA both in HD and PD is sufficiently high to allow the removal of this chelating agent in patients with renal failure.

Wainer, E.; Boner, G.; Lubin, E.; Rosenfeld, J.B.

1981-09-01

320

Insensitivity of Tc-99m pertechnetate for detecting metastases of differentiated thyroid carcinoma  

SciTech Connect

To evaluate the use of Tc-99m pertechnetate whole body scanning for the detection of metastases of differentiated thyroid carcinoma, the authors performed sequential Tc-99m pertechnetate and I-131 scans in five patients with known or suspected metastatic thyroid cancer. All five patients had abnormal I-131 uptake, but only two patients had abnormal Tc-99m pertechnetate uptake. A total of 33 abnormal foci were located with I-131; Tc-99m pertechnetate detected only 3 of these foci, and did not demonstrate any foci that were not apparent with I-131. Despite the theoretical advantages of Tc-99m pertechnetate, it cannot be recommended as a substitute for I-131 for locating thyroid cancer metastases.

Campbell, C.M.; Khafagi, F.A. (Royal Brisbane Hospital (Australia))

1990-01-01

321

Involvement of the glutathione S-conjugate compounds and the MRP protein in Tc99m-tetrofosmin and Tc99m-sestamibi uptake in glioma cell lines  

Microsoft Academic Search

The objective of this study was to compare the accumulation of Tc-99m-tetrofosmin and Tc-99m-sestamibi in four grade IV glioma cell lines and to correlate their accumulation with the multidrug resistance of the cells. Tc-99m-tetrofosmin in all glioma cell lines showed slightly higher uptake and more efficient release beyond 150 min than Tc-99m-sestamibi and the retention of both tracers in the

Nathalie Perek; Nathalie Prevot; Franēoise Koumanov; Delphine Frere; Odile Sabido; Patrick Beauchesne; Francis Dubois

2000-01-01

322

Tc-99m DMSA renal scintigraphy during kidney maturation.  

PubMed

A total of 282 renal scintigrams with Tc-99m DMSA in 238 children ranging in age from 10 days to 13 years performed during a 3-year period were reviewed. The authors present 94 kidneys in 85 children in whom no sign of pathology was demonstrated clinically, either by ultrasound or intravenous urography, or by micturating urethrocystography. By exploring homogeneity or heterogeneity of tracer distribution, kidney length, and background level, the authors were able to identify a "normal" pattern of tracer distribution according to age. They found that the average kidney length was 56 mm at birth, growing 1 mm per month during the first year of life, and 4 mm per year thereafter, until puberty. Average background activity was 14% of the average kidney activity at birth which decreased to approximately 6% during the first year of life, with no further decrease thereafter. PMID:7750212

Bajc, M; Wallin, L

1995-03-01

323

Clinical experience with Tc-99m nofetumomab merpentan (Verluma) radioimmunoscintigraphy.  

PubMed

Tc-99m nofetumomab merpentan (Verluma), consisting of a Fab fragment of the pancarcinoma murine antibody NR-LU-10, has been previously evaluated as a diagnostic imaging agent in staging patients with lung cancer. The authors have taken advantage of the pancarcinoma reactivity of this antibody to select patients with a variety of carcinomas for radioimmunotherapy trials. These have included gastrointestinal, breast, ovary, pancreas, kidney, cervix, and bladder carcinoma. This article documents the range of tumor types and locations that can be identified by gamma camera imaging with this radioimmunoconjugate. Tumor was positively identified in 92% of 107 patients studied. In 15 patients, the images led to suspicion of previously unknown disease. The authors conclude that this radioimmunoconjugate is useful in assessing patients with advanced disease. Additional studies may be warranted to explore further the potential benefit of this diagnostic imaging agent in evaluating the extent of disease in patients with a variety of carcinomas. PMID:9298295

Breitz, H B; Tyler, A; Bjorn, M J; Lesley, T; Weiden, P L

1997-09-01

324

A new constitutive relationship for alloy TC11  

NASA Astrophysics Data System (ADS)

Engineers need constitutive relationships for planning engineering of high quality forgings. Accordingly, accurately describing the mechanical performance of material deformation is of decisive importance. In this paper, a new method is presented, in which a four-layer backpropagation neural network is built to acquire the constitutive relationship of the TC11 alloy based on the homogeneous compression test. Temperature, effective strain, and effective strain rate are used as the input vectors of the neural network, and the output of the neural network is the flow stress. After the network is trained with experimental data, it correctly reproduces the flow stress in the sampled data. Furthermore, when the network is presented with nonsampled data, it also correctly predicts the flow stress.

Liu, Q.; Fu, Z.; Wu, S.; Yang, H.

1997-08-01

325

Growth of high Tc superconducting thin films for microwave applications  

SciTech Connect

High-{Tc} superconducting thin films of YBa{sub 2}Cu{sub 3}O{sub 7 {minus}{delta}} (YBCO) were deposited on sapphire substrates with buffer layers of yttria-stabilized zirconia and cerium oxide by using pulsed laser deposition (PLD) technique. The epitaxial relationship between the substrate and buffer layers as well as the buffer layer and the superconducting film was established. Furthermore, using the same thin film technique, YBCO superconducting thin films were deposited on both sides of substrates of up to 5 cm in diameter. The superconducting properties of the films on both the sapphire with buffer layers and large-area substrates were comparable to the ones of the best YBCO films. 8 refs., 6 figs.

Wu, X.D.; Foltyn, S.R.; Muenchausen, R.E.; Dye, R.C.; Cooke, D.W.; Rollett, A.D.; Garcia, A.R.; Nogar, N.S. (Los Alamos National Lab., NM (USA)); Pique, A.; Edwards, R. (Neocera, New Brunswick, NJ (USA))

1991-01-01

326

Macroscopic Quantum Tunneling in HIGH-TC Superconductor Josephson Junctions  

NASA Astrophysics Data System (ADS)

We investigate the macroscopic quantum tunneling (MQT) in d-wave high-Tc superconductor Josephson junctions. Using the path-integral method, we analytically obtain the MQT rate for the c-axis twist Josephson junctions. In the case of the zero twist angle, the system shows the super-Ohmic dissipation due to the presence of the nodal quasiparticle tunneling. Therefore, the MQT rate is largely suppressed compared with the finite twist angle cases. Furthermore, the effect of the zero energy bound states (ZES) on the MQT in the in-plane junctions is theoretically investigated. We obtained the analytical formula of the MQT rate and showed that the presence of the ZES at the insulator/superconductor interface leads to a strong Ohmic quasiparticle dissipation. Therefore, the MQT rate is noticeably inhibited compared with the c-axis junctions in which the ZES are completely absent.

Kawabata, Shiro

2006-06-01

327

Synthesis and characterization of cationic technetium complexes of 1,2-bis(dimethylphosphino)ethane (DMPE): structure determinations of trans-(Tc/sup v/(DMPE)/sub 2/(OH)(O))(F/sub 3/CSO/sub 3/)/sub 2/, trans-(Tc/sup III/(DMPE)/sub 2/Cl/sub 2/)F/sub 3/CSO/sub 3/, and (Tc/sup I/(DMPE)/sub 3/)/sup +/ using x-ray diffraction, EXAFS, and /sup 99/Tc NMR  

SciTech Connect

Three distinct cationic complexes of technetium, containing Tc(V), Tc(III), and Tc(I) centers, have been prepared by reduction of pertechnetate with bis(1,2-dimethylphosphino)ethane (DMPE). Careful control of reaction conditions allows the synthesis of any one of three trans-complexes in greater than 90% yield. All complexes have been characterized by visible-, uv-, and ir-spectrophotometry, elemental analyses, and high-performance liquid chromatography. The Tc(I) complex has been additionally characterized by /sup 31/P and /sup 99/Tc NMR, as well as a new type of extended x-ray absorption fine structure analysis (EXAFS), which show that this is an octahedral species with a Tc-P bond length of 2.40A. The Tc(V) and Tc(III) complexes have been additionally characterized by single-crystal x-ray analyses.

Vanderheyden, J.L.; Ketring, A.R.; Libson, K.; Heeg, M.J.; Roecker, L.; Motz, P.; Whittle, R.; Elder, R.C.; Deutsch, E.

1984-09-26

328

Microwave generator  

DOEpatents

A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit there through effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators. 6 figs.

Kwan, T.J.T.; Snell, C.M.

1987-03-31

329

Quantification of the interaction of Tc with dissolved boom clay humic substances.  

PubMed

Technetium-99 (Tc), a fission product of uranium-238, is an important radionuclide because of its long half-life and its high yield in radioactive waste. To elucidate the Tc geochemical behavior in reducing environments relevant to geological disposal and in the presence of humic substances (HS), experiments were set up that resulted forthe first time in the determination of an interaction constant for Tc with dissolved humic substances. A number of lab-scale Boom Clay (a possible geological underground High-Level Radioactive Waste storage site in Mol, Belgium) batch experiments were set up, combining both different initial Tc(VII) concentrations and different solid/liquid ratios. On these batches several sequential extraction steps with HS-free synthetic Boom Clay water were performed. Equilibration times were fixed at 1 week for each extraction step. Tc(VII) was found to be readily reduced to Tc(IV) by the solid Boom Clay phase. This solid phase was able to sorb Tc(IV) to a very large extent (log Kd approximately 2.5-4.0), and two sorption sinks (one of which is humic substances) were detected. In solution, Tc(IV) was mainly associated with HS. Concentrations in solution were found up to the order of 2 x 10(-6) M. The results were quantitatively described as a competition for Tc(IV) between the solid phase and the dissolved HS (Schubert-like approach). It was concluded that a hydrophobic sorption of uncharged Tc(IV) species in solution would act as the dominating interaction mechanism with HS, with an interaction constant log K(HS) = 5.3 +/- 0.3. PMID:12636274

Maes, A; Bruggeman, C; Geraedts, K; Vancluysen, J

2003-02-15

330

Bromocriptine enhances the uptake of 99mTc-MIBI in patients with hepatocellular carcinoma  

PubMed Central

99mTc-methoxyisobutyl isonitrile (MIBI) is a suitable transport substrate for the multidrug resistance gene product P-glycoprotein (P-gp) and widely used for tumor imaging. Bromocriptine has been shown to inhibit the ATPase activity and the function of P-gp. We hypothesized that bromocriptine could promote the accumulation of MIBI by inhibiting P-gp activities, a feature that can be taken advantage of for enhancing 99mTc-MIBI imaging. In the current study, we sought to investigate whether bromocriptine enhanced the uptake of 99mTc-MIBI in hepatocellular carcinoma patients. Sixty primary hepatocellular carcinoma patients received 99mTc-MIBI single photon emission computer tomgraphy (SPECT) prior to surgery. 99mTc-MIBI SPECT was performed 15 and 120 min after injection of 20 mCi 99mTc-MIBI, and early uptake, delayed uptake (L/Nd), and washout rate (L/Nwr) of 99mTc-MIBI were obtained. In addition, a second 99mTc-MIBI SPECT was performed according to the same method 48 h after bromocriptine administration. We found that, prior to bromocriptine administration, significant MIBI uptake in tumor lesions was noted in only 10 (16.7%, 10/60) patients with hepatocellular carcinoma. No significant MIBI uptake was observed in the tumor lesions of the remaining 50 (83.3%, 50/60) hepatocellular carcinoma patients. Following bromocriptine administration, all the patients without apparent MIBI uptake demonstrated significant MIBI uptake on 99mTc-MIBI SPECT (P < 0.05). Our findings indicate that bromocriptine enhances the uptake of 99mTc-MIBI in patients with hepatocellular carcinoma.

Chai, Xiangting; Liu, Qiaoyu; Shao, Wenyu; Zhang, Feng; Wang, Xuehao; Wang, Hai

2012-01-01

331

Submillimeter residual losses in high-{Tc} superconductors  

SciTech Connect

Bolometry was used obtain accurate submillimeter residual loss data for epitaxial films of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO), Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10}, Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8} (TCBCO), and Ba{sub 0.6}K{sub 0.4}BiO{sub 3} (BKBO). We were able to fit the absorptivity measured for Nb films to an Eliashberg strong coupling calculation; excellent agreement resulted between parameters from best fits and measured Residual Resistivity Ratio. Microwave surface resistance measurements made on the same YBCO and TCBCO films are in excellent agreement with submillimeter measurements. Absorptivities for all YBCO films studied are qualitatively similar, increasing smoothly with frequency, with no gap-like features below the well known absorption edge at 450 cm{sup {minus}1}. Losses in YBCO films were fit to a weakly coupled grain model for the a-b plane conductivity. Strong phonon structure was observed in TCBCO films between 60 and 700 cm{sup {minus}1} (2 THz and 23 THz); these losses could not be fitted to the simple weakly coupled grain model, in contrast to the case for other high-{Tc} superconductors where phonon structure observed in ceramics are is absent in epitaxial oriented films and crystals because of electronic screening due to high conductivity of a-b planes. Absorptivity data for the BKBO films all show a strong absorption onset near the BCS tunneling gap of 3.5 k{sub B}{Tc}. Comparison with strong coupling Eliashberg predictions and of a Kramers-Kronig analysis indicate that the absorption onset is consistent with a superconducting energy gap. Effects of magnetic field on residual losses in YBCO films show a resonant absorption feature in vicinity of predicted

Miller, D.

1993-09-01

332

The recovery of asteroid 2008 TC[subscript 3  

SciTech Connect

On October 7, 2008, asteroid 2008 TC{sub 3} impacted Earth and fragmented at 37 km altitude above the Nubian Desert in northern Sudan. The area surrounding the asteroid's approach path was searched, resulting in the first recovery of meteorites from an asteroid observed in space. This was also the first recovery of remains from a fragile 'cometary' PE = IIIa/b type fireball. In subsequent searches, over 600 mostly small 0.2-379 g meteorites (named 'Almahata Sitta') with a total mass 10.7 kg were recovered from a 30 x 7 km area. Meteorites fell along the track at 1.3 kg km{sup -1}, nearly independent of mass between 1 and 400 g, with a total fallen mass of 39 {+-} 6 kg. The strewn field was shifted nearly 1.8 km south from the calculated approach path. The influence of winds on the distribution of the meteorites, and on the motion of the dust train, is investigated. The majority of meteorites are ureilites with densities around 2.8 g cm{sup -3}, some of an anomalous (porous, high in carbon) polymict ureilite variety with densities as low as 1.5 g cm{sup -3}. In addition, an estimated 20-30% (in mass) of recovered meteorites were ordinary, enstatite, and carbonaceous chondrites. Their fresh look and matching distribution of fragments in the strewn field imply that they were part of 2008 TC{sub 3}. For that reason, they are all referred to as 'Almahata Sitta.' No ureilite meteorites were found that still held foreign clasts, suggesting that the asteroid's clasts were only loosely bound.

Shaddad, Muawia H.; Jenniskens, Peter; Numan, Diyaa; Kudoda, Ayman M.; Elsir, Saadia; Riyad, Ihab F.; Ali, Awad Elkareem; Alameen, Mohammed; Alameen, Nada M.; Eid, Omer; Osman, Ahmed T.; AbuBaker, Mohamed I.; Yousif, Mohamed; Chesley, Steven R.; Chodas, Paul W.; Albers, Jim; Edwards, Wayne N.; Brown, Peter G.; Kuiper, Jacob; Friedrich, Jon M. (CIT); (Juba); (RNMI-Netherlands); (Khartoum); (UWO); (SETI); (Fordham)

2011-09-06

333

Theory of HIGH-TC Superconductivity in Layered Cuprates  

NASA Astrophysics Data System (ADS)

A model of superconductivity in high-temperature superconducting layered cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of Tc, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature, etc. The resonant tunneling mechanism for the c-axis transport is proposed. Real physical properties are calculated and compared with experimental data. These include the temperature dependence of the static c-axis conductivity in the normal state, frequency dependence of the optical conductivity and stationary supercurrent along the c-axis. It is demonstrated that for the latter the coherence of resonant tunneling through different centers is of primary importance. The resonant tunneling idea is used for description of the origin and some properties of the "pseudogap phase". The superconducting critical temperature in this picture is defined at low doping by establishment of a 3-dimensional phase correlation between the layers, and at high doping by destruction of a d-wave superconductivity by disorder. The result is a nonmonotonic dependence of Tc on doping. The pseudogap phase is described on the basis of the Franz-Millis model of superconducting fluctuations, consisting of small superconducting domains with uncorrelated supercurrents. The calculated characteristics, namely, the spectral function, the inelastic neutron scattering cross section, and the spin susceptibility agree with experimental data.

Abrikosov, A. A.

2003-04-01

334

Effect of extracorporeal piezoelectric lithotripsy shock waves on renal function measured by Tc-99m-DMSA using SPECT.  

PubMed

Extracorporeal shock-wave lithotripsy has altered the therapeutic approach to urinary stone disease. Recently, a method was developed in which shock-wave generation is obtained piezoelectrically. To evaluate the effect of extracorporeal piezoelectric lithotripsy (EPL) on renal function, 20 patients were studied prior to and after EPL of renal calculi. Renal cortical function was evaluated by using a previously described and validated quantitative single photon emission computerized tomography (SPECT) method to measure individual absolute uptake of technetium-99m dimercaptosuccinic acid (Tc-99m-DMSA). Twenty kidneys were treated, and the 19 contralateral kidneys were without stone disease (1 patient had a single kidney). The absolute kidney uptake of Tc-DMSA in the normal kidneys was 21.4% +/- 6.2% before and 22.2% +/- 6.4% after EPL. For the treated kidneys the absolute update was 16.8% +/- 5.3% and 16.8% +/- 4.7% before and after, respectively. There was no statistical significant difference between pre- and post-treatment values. The absolute kidney uptake was significantly lower (p less than 0.01) in the treated than in the normal kidneys. This study indicates that the EPL procedure did not cause any damage to cortical function detectable by the DMSA uptake. PMID:1660635

Groshar, D; Ginessin, J; Moskovitz, B; Frenkel, A; Israel, O; Levin, D R; Front, D

1991-12-01

335

Sorption coefficients and molecular mechanisms of Pu, U, Np, Am and Tc to Fe (hydr)oxides: a review.  

PubMed

Pu, U, Np, Am and Tc are among the major risk drivers at nuclear waste management facilities throughout the world. Furthermore, uranium mining and milling operations have generated an enormous legacy of radioactively contaminated soils and groundwater. The sorption process of radionulcides onto ubiquitous Fe (hydr)oxides (FHOs; hematite, magnetite, goethite and ferrihydrite) is one of the most vital geochemical processes controlling the transport and fate of radionuclides and nuclear wastes in the subsurface zones. Meanwhile, understanding molecular-level chemical speciation of radionuclides onto FHOs is crucial to model their behavior in subsurface environments, and to develop new technologies for nuclear waste treatment and long-term remediation strategies for contaminated soils and groundwater. This review article aims (1) to provide risk or performance assessment modelers with macroscopic distribution coefficient (K(d)) data of Pu, U, Np, Am and Tc onto FHOs under different conditions (pH, radionuclide concentration, solution ion strength, sorbent loading, partial pressure of CO(2) (P CO(2)), equilibrium time) pertinent to environmental and engineered systems, and (2) to provide a microscopic or molecular-level understanding of the chemical speciation and sorption processes of these radionuclides to FHOs. PMID:23141377

Li, Dien; Kaplan, Daniel I

2012-09-14

336

{sup 99m}Tc DTPA aerosol clearances in the assessment of radiation injury top the lung  

SciTech Connect

In a prospective study, 36 patients with inoperable lung Ca. (sq. cells-24, adeno-5, largecell-2, unknown-5) underwent pre and post radiation {sup 99m}Tc DTPA aerosol clearance studies. The aim was to evaluate the value of aerosol clearance in the prediction of radiation injury to the regions other than the radiation field. Aerosol study was done using a commercially available nebulizer, dynamic images were obtained (30 sec/frame) in the posterior projection for a duration of 45 min. ROIs were drawn on upper, mid and lower zones on either lung, and time activity curves were generated. Using a linear fit, clearance half time (t{sub 1/2}) was calculated, for all six curves. The difference between pre and post radiation (t{sub 1/2}) was compared to the clinical follow up of each patient and a difference of more than 15 minutes was considered positive. Of the 36 patients 12 had a t{sub 1/2} difference of more than 15 minutes. Of these 5 patients had radiation pulmonlitis and the remaining 7 had respiratory failure due to infection and uremia. 24 patients had a t{sub 1/2} difference of less than 15 minutes and their clinical follow-up did not reveal any evidence of pulmonary radiation injury during this period. The results indicate that the clearance of Tc-99m DTPA aerosols is effective for excluding radiation pulmonlitis.

Halkar, R.K.; Raghab, A.; Higazi, E. [Kuwait Univ. (Kuwait)] [and others

1994-05-01

337

Lessons from the tc-99m shortage: implications of substituting tl-201 for tc-99m single-photon emission computed tomography.  

PubMed

Background- In 2009, the Chalk River nuclear reactor closed for repairs that led to a critical shortage of technetium-99m (Tc-99m). Several centers used thallium-201 (Tl-201) as an alternative radiotracer for myocardial perfusion imaging. Because Tl-201 is considered by many as a suboptimal radiotracer, we sought to understand the impact of using Tl-201 (during the Tc-99m shortage) on downstream resource utilization. Methods and Results- We performed a retrospective study at the Ottawa Heart Institute of 7402 patients (60% men; mean age, 62.6±11.8 years), patients were referred for myocardial perfusion imaging between May 2008 and January 2011 (PRE_Tc-99m [2938 patients]), during (DURING_Tl-201 [2959 patients]), and after (POST_Tc-99m [1505 patients]) the Tc-99m shortage. Patients were followed for 6 months after their index myocardial perfusion imaging to determine subsequent rates of cardiac catheterization or noninvasive imaging. More downstream testing was seen in the Tl-201 cohort (639 [21.4%] patients) than the Tc-99m cohort (537 [12.1%] patients; P<0.001). After adjustment using propensity scores, differences in downstream referral rates were maintained. The downstream investigations resulted in an estimated increase in per-patient costs ($165.22; 95% confidence interval, 153.00-177.42) in the DURING_Tl-201 cohort compared with the Tc-99m cohort ($90.97; 95% confidence interval, 83.42-98.90; P<0.001). As well, the mean effective radiation dose per-patient was higher in DURING_Tl-201 (23.57 mSv; 95% confidence interval, 23.16-23.96) than in Tc-99m (12.92 mSv; 95% confidence interval, 12.55-13.40; P<0.001). Conclusions- In this single-center study, the use of Tl-201 during the Tc-99m shortage was associated with an increase in downstream testing, cost, and patient radiation exposure, but these findings may not be generalizable to other centers. Although Tl-201 provided a short-term solution to the unexpected Tc-99m shortage, long-term cost-effective solutions should be areas of future study. PMID:23873401

Small, Gary R; Ruddy, Terrence D; Simion, Oana; Alam, Mohammed; Fuller, Lyanne; Chen, Li; Beanlands, Rob S; Chow, Benjamin J W

2013-07-19

338

Basic aqueous chemistry of [M(OH 2) 3(CO) 3] + (M=Re, Tc) directed towards radiopharmaceutical application  

Microsoft Academic Search

A review on the synthesis and properties of the organometallic aqua-ion [M(OH2)3(CO)3]+ (M=Re, 99Tc, 99mTc), as relevant for radiopharmaceutical application, is presented. These important starting compounds can be prepared quantitatively, (a) on the no carrier added (n.c.a.) level (99mTc) in water, or (b) in organic solvents (Re, 99Tc) at atmospheric pressure in a short time and from [MO4]?. The main

Roger Alberto; Roger Schibli; Robert Waibel; Ulrich Abram; August P. Schubiger

1999-01-01

339

Accumulation and release of 99 Tc by a macrophyte of the Yenisei River ( Elodea canadensis ) in laboratory experiments  

Microsoft Academic Search

The study addresses 99Tc accumulation and release by Elodea canadensis, one of the abundant species of submerged plants in the Yenisei River 99Tc in water samples of the “Elodea-Yenisei River water” model system and in the biomass fractions was measured using a liquid scintillatio analyzer. Experiments\\u000a on accumulation of 99Tc by Elodea showed that 99Tc activity concentration can reach 120±6

A. Bolsunovsky; L. Bondareva

2008-01-01

340

Lipid Raft Targeting of the TC10 Amino Terminal Domain Is Responsible for Disruption of Adipocyte Cortical Actin  

Microsoft Academic Search

Overexpression of the Rho family member TC10, disrupts adipocyte cortical actin structure and inhibits insulin-stimulated GLUT4 translocation when targeted to lipid raft microdomains. This appears to be independent of effecter domain function because overexpression of the wild-type (TC10\\/WT), constitutively GTP-bound (TC10\\/Q75L), and constitutively GDP bound (TC10\\/ T31N) all inhibit adipocyte cortical actin structure and GLUT4 translocation. To examine the structural

June Chunqiu Hou; Jeffrey E. Pessin

2003-01-01

341

Shopping generation  

Microsoft Academic Search

Reports research by the National Consumer Council (NCC) into UK children’s experiences and views as consumers; this survey of 10 to 19 year olds found that they form a new shopping generation which is more even consumer brand oriented than American counterparts but feels vulnerable and is critical of shops, companies and advertisers. Outlines the NCC recommendations for a children’s

Ed Mayo

2005-01-01

342

Generation Next  

ERIC Educational Resources Information Center

|There is a shortage of accounting professors with Ph.D.s who can prepare the next generation. To help reverse the faculty deficit, the American Institute of Certified Public Accountants (CPAs) has created the new Accounting Doctoral Scholars program by pooling more than $17 million and soliciting commitments from more than 70 of the nation's…

Hawkins, B. Denise

2010-01-01

343

MO tripeptide diastereomers (M=99/99mTc, Re): models to identify the structure of 99mTc peptide targeted radiopharmaceuticals.  

PubMed

Biologically active molecules, such as many peptides, serve as targeting vectors for radiopharmaceuticals based on 99mTc. Tripeptides can be suitable chelates and are easily and conveniently synthesized and linked to peptide targeting vectors through solid-phase peptide synthesis and form stable TcVO complexes. Upon complexation with [TcO]3+, two products form; these are syn and anti diastereomers, and they often have different biological behavior. This is the case with the approved radiopharmaceutical [99mTcO]depreotide ([99mTcO]P829, NeoTect) that is used to image lung cancer. [99mTcO]depreotide indeed exhibits two product peaks in its HPLC profile, but assignment of the product peaks to the diastereomers has proven to be difficult because the metal peptide complex is difficult to crystallize for structural analysis. In this study, we isolated diastereomers of [99TcO] and [ReO] complexes of several tripeptide ligands that model the metal chelator region of [99mTcO]depreotide. Using X-ray crystallography, we observed that the early eluting peak (A) corresponds to the anti diastereomer, where the Tc=O group is on the opposite side of the plane formed by the ligand backbone relative to the pendant groups of the tripeptide ligand, and the later eluting peak (B) corresponds to the syn diastereomer, where the Tc=O group is on the same side of the plane as the residues of the tripeptide. 1H NMR and circular dichroism (CD) spectroscopy report on the metal environment and prove to be diagnostic for syn or anti diastereomers, and we identified characteristic features from these techniques that can be used to assign the diastereomer profile in 99mTc peptide radiopharmaceuticals like [99mTcO]depreotide and in 188Re peptide radiotherapeutic agents. Crystallography, potentiometric titration, and NMR results presented insights into the chemistry occurring under physiological conditions. The tripeptide complexes where lysine is the second amino acid crystallized in a deprotonated metallo-amide form, possessing a short N1-M bond. The pKa measurements of the N1 amine (pKa approximately 5.6) suggested that this amine is rendered more acidic by both metal complexation and the presence of the lysine residue. Furthermore, peptide chelators incorporating a lysine (like the chelator of [TcO]depreotide) likely exist in the deprotonated form in vivo, comprising a neutral metal center. Deprotonation possibly mediates the interconversion process between the syn and anti diastereomers. The N1 amine group on non-lysine-containing metallopeptides is not as acidic (pKa approximately 6.8) and does not deprotonate and crystallize as do the metallo-amide species. Three of the tripeptide ligands (FGC, FSC, and FKC) were radiolabeled with 99mTc, and the individual syn and anti isomers were isolated for biodistribution studies in normal female nude mice. The main organs of uptake were the liver, intestines, and kidneys, with the FGC compounds exhibiting the highest liver uptake. In comparing the diastereomers, the syn compounds had substantially higher organ uptake and slower blood clearance than the anti compounds. PMID:17691766

Cantorias, Melchor V; Howell, Robertha C; Todaro, Louis; Cyr, John E; Berndorff, Dietmar; Rogers, Robin D; Francesconi, Lynn C

2007-08-11

344

Infected knee prosthesis: diagnosis with In-111 leukocyte, Tc-99m sulfur colloid, and Tc-99m MDP imaging  

SciTech Connect

Forty-one possible cases of infected total knee prostheses studied with indium-111-labeled leukocyte scintigraphy were retrospectively reviewed. Twenty-four of the prostheses were studied with technetium-99m methylene diphosphonate bone scintigraphy and 19 with Tc-99m sulfur colloid marrow scintigraphy. Nine prostheses were infected, and 32 were uninfected. The accuracy of combined labeled leukocyte and sulfur colloid marrow imaging (95%) was higher than that of labeled leukocyte scintigraphy alone (78%), bone scintigraphy alone (74%), or combined labeled leukocyte and bone scintigraphy (75%). The authors conclude that combined labeled leukocyte and sulfur colloid imaging is an accurate method for diagnosis of infected knee prostheses. In this series, this technique was superior to labeled leukocyte and bone imaging, alone or in combination.

Palestro, C.J.; Swyer, A.J.; Kim, C.K.; Goldsmith, S.J. (Mount Sinai School of Medicine, New York, NY (USA))

1991-06-01

345

Differential conductivity mapping of solar panels using a high-TC superconductor SQUID  

NASA Astrophysics Data System (ADS)

To visualise the distribution of the electric property of solar cells, we developed a differential conductivity mapping system using high-TC (HTS-) superconductor SQUID with a normal conducting pick-up coil. The bias ac voltage with an offset voltage was applied to a solar panel made from amorphous silicon, and the normal component of the generated magnetic field was lock-in-detected. Thus the measured signal was converted to dB/dV properties, which are inverse-proportional to the differential resistivity, as the function of the offset voltage. By scanning the pick-up coil across the panel surface, we obtained the distribution of dB/dV properties across the solar panel was obtained by scanning the pick-up coil across the panel surface. The distribution of dB/dV on the panel differed between when the light source was on and when it was off. This result suggests that the proposed system is a potential tool for diagnosing the electric properties of solar cells.

Kiwa, T.; Maeda, S.; Miyake, K.; Kataoka, N.; Tsukamoto, A.; Adachi, S.; Tanabe, K.; Kandori, A.; Tsukada, K.

2011-11-01

346

A comparison of single plasma sample methods to estimate renal clearance using 99mTc-ethylenedicysteine and 99mTc-mercaptoacetyltriglycine.  

PubMed

Several single sample methods for determination of (99m)Tc-mercaptoacetyltriglycine (MAG3) clearance are being used clinically. Kabasakal et al. proposed a similar formula for (99m)Tc-ethylenedicysteine (EC). This study was performed to compare his method with Bubeck et al. formula for (99m)Tc-MAG3 already in use. Twenty-eight subjects divided in two groups were registered which included 22 patients with various renal diseases (group-I) and six normal volunteers (group II). All subjects were studied twice using both the radiopharmaceuticals. The images and renogram parameters, that is TMAX and T1/2 of both the agents, were similar in all the subjects. The clearance of the (99m)Tc-EC was however considerably higher than (99m)Tc-MAG3 in both the groups (mean ± SEM =279 ± 14 ml min(-1)/1.73 m(2) versus 177 ± 15 ml min(-1)/1.73 m(2) in group-I and 377 ± 11.90 ml min(-1)/1.73 m(2) versus 238 ± 8.23 ml min(-1)/1.73 m(2) in group II). This difference was more pronounced in cases with reduced renal functions. Among the Effective Renal Plasma Flow (ERPF) values determined from EC and MAG3 clearances in six normal volunteers, four cases only in MAG3 had ERPF below the lower limit. This study has demonstrated superiority of single sample method for (99 m)Tc-EC clearance over its analogous method for (99m)Tc-MAG3. PMID:23701132

Sohaib, Muhammad; Rafique, Asif; Saeed, Shabana; Afshan, Anjum

2013-03-18

347

Development of a technological base for a solar steam generator  

SciTech Connect

The purpose of this program is to develop a technological base from which cost effective solar industrial steam generation systems could be designed. A specific goal of the program were to design and then build a heat pipe/GE TC-300 solar collector. Further objectives, which were added later in the program, included design and testing of an unfired boiler and reconstruction of the system using U-tubes in lieu of heat pipes in the collectors.

Thomas, W.E. Jr.

1981-01-01

348

Impact of Mobile-Immoble Water on the Transport of Technetium (Tc-99) in Unsaturated Sediments  

NASA Astrophysics Data System (ADS)

Technetium has been released to the environment through nuclear power production and nuclear fuel processing; as a result, further spreading of Tc-99 is a concern at DOE sites across the US. The current body of work conducted on Tc-99 has provided a wealth of information regarding the redox relationships, sorption, solubility, and stability of the mineral phases, however little work has been conducted on the physical transport of the highly soluble pertechnetate oxyanion, in the subsurface. Current conceptual models do not explain the presence and persistence of the anion in deep vadose zone environments such as the Hanford, WA site. As new in situ remediation technologies are developed and remediation continues; it is necessary to understand implications for Tc-99 transport and mobilization in unsaturated systems. Specifically, foam and gas phase remediation could potentially alter established flow regimes by changing moisture content, flow paths, and surface reactivity of sediments; therefore, it is imperative to understand fundamental transport properties of Tc-99 in the context of physical and chemical constraints. Using an Unsaturated Flow Apparatus (UFA) we have conducted a series of experiments to examine the impact of mobile-immobile domains on the transport of Tc-99. By varying sand/silt ratios and saturations we examined how changes in pore morphology and moisture content impact the transport of Tc-99 within our experimental system. Results demonstrating the impact of sediment texture, pore morphology and soil moisture content on Tc-99 transport will be presented.

Jansik, D. P.; Wellman, D. M.; Cordova, E.; Wildenschild, D.

2010-12-01

349

Preparation and in-vivo evaluation of 99mTc-IOTIDA for cholescintigraphy.  

PubMed

The synthesis, radiolabeling and in vivo evaluation of 99mTc-IOIDA(3-iodo 2,4,6-trimethylpheyl carbamoylmethyl iminodiacetic acid) for the assessment of hepatocytic function and the functional status of the cystic duct and the gallbladder are described. For a scintigraphic imaging comparison, three different 99mTc-IDA derivatives, 99mTc-DISIDA, 99mTc-mebrofenin and 99mTc-IOTIDA, were prepared and evaluated for their in vivo pharmacokinetic behavior through animal studies. Serial static image scans of rabbits injected with 99mTc-IOTIDA revealed that none of the tissues except the hepatobiliary system showed radioactivity concentrations. A scintigraphic study in a healthy volunteer showed that most of the administrated radioactivity accumulated in the liver and was rapidly excreted through the hepatobiliary system, visualizing the gallbladder within 15 min. In conclusion, 99mTc-IOTIDA is a potential hepatobiliary imaging agent for the evaluation of the functional status of hepatocytes and the patency of the biliary duct. PMID:15388121

Hong, Young-Don; Jang, Beom-Su; Choi, Sang-Mu; Park, Woong-Woo; Park, Kyung-Bae; Choi, Sun-Ju

2004-12-01

350

Optical imaging of Tc-99m-based tracers: in vitro and in vivo results  

NASA Astrophysics Data System (ADS)

It has been recently shown that optical imaging (OI) methods can be used to image the in vivo biodistribution of several radiopharmaceuticals labeled with beta or alpha emitters. In this work particular attention has been focused on investigating the weaker optical signal induced by an almost pure gamma emitter like Tc-99m. Visible light emission measurements of a water solution containing Tc-99m were performed using a small animal OI system. A sequence of images was acquired for 24 h in order to study the decay of the luminescence signal. The difference between the luminescence decay half life and well-known Tc-99m half life was equal to 1%. in vivo imaging was performed by injecting one control nude mice with Tc-99m-MDP. Optical images obtained with equipment designed for bioluminescence imaging showed that a visible light emission was distinguishable and correctly localized in the bladder region where a higher concentration of Tc-99m-MDP was expected. The bladder to background ratio was always greater than 1. We conclude that the experimental data presented in this paper show that it is possible to detect in vivo luminescence optical photons induced by Tc-99m. This is important especially considering the large number of Tc-99m-based radiopharmaceutical currently available.

Spinelli, Antonello E.; Meo, Sergio Lo; Calandrino, Riccardo; Sbarbati, Andrea; Boschi, Federico

2011-11-01

351

Hydrogen isotope measurements of organic acids and alcohols by Pyrolysis-GC-MS-TC-IRMS  

NASA Astrophysics Data System (ADS)

One possible process responsible for methane generation on Mars is abiotic formation by Fischer-Tropsch-type (FTT) synthesis during serpentinization reactions. Measurement of carbon and hydrogen isotopes of intermediary organic compounds can help constrain the origin of this methane by tracing the geochemical pathway during formation. Of particular interest within the context of this work is the isotopic composition of organic intermediaries produced on the surfaces of mineral catalysts (i.e. magnetite) during hydrothermal experiments, and the ability to make meaningful and reproducible hydrogen isotope measurements. Reported here are results of experiments to characterize the hydrogen isotope composition of low molecular weight organic acids and alcohols. The presence of these organic compounds has been suggested by us and others as intermediary products made during mineral surface catalyzed reactions. This work compliments our previous study characterizing the carbon isotope composition of similar low molecular weight intermediary organic compounds (Socki, et al, American Geophysical Union Fall meeting, Abstr. #V51B-2189, Dec., 2010). Our hydrogen isotope measurements utilize a unique analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-High Temperature Conversion-Isotope Ratio Mass Spectrometry (Py-GC-MS-TC-IRMS). Our technique is unique in that it carries a split of the pyrolyzed GC-separated product to a Thermo DSQ-II° quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of separated organic compounds, therefore both chemical and isotopic measurements can be carried out simultaneously on the same sample. Samples of carboxylic acid (C1 through C4) and alcohols (C1 through C4) were pyrolyzed at 200°C on a CDS Analytical. Inc. Model 5200° pyroprobe and passed through a Thermo Electron GC-MS-TC-IRMS system operating in continuous flow mode. The High Temperature Conversion step (1450°C) converts organic compounds directly to hydrogen gas (Burgoyne and Hayes, Anal. Chem. 70, p. 5136 [1998]). Average ?D values range from -247.5% (V-SMOW) for ethanol, to -68% (V-SMOW) for ethanoic acid. Reproducibility using this method is typically better than ±3.4% for organic acids and ±0.8% for alcohols. We are continuing to investigate the reliability of this pyrolysis technique for making hydrogen isotope measurements of mineral surface catalyzed organic compounds.

Socki, R. A.; Fu, Q.; Niles, P. B.

2011-12-01

352

Monoclonal antibodies (MAb) made against insect-derived metacyclic trypomastigotes (IMT) of Trypanosoma cruzi (TC) cross-react with other parasite forms  

SciTech Connect

Considerable information has been generated in recent years about stage-specific surface membrane antigens of a number of protozoa, and this phenomenon has been observed among several stages of TC as well. However, little is known about the surface antigens of IMT, the true infective stage of TC, because of the difficulty of obtaining sufficient numbers of these organisms for analysis. The Tulahuen strain of TC was maintained in the reduviid vector Dipetalogaster maximus by repeated feeding on mice with high parasitemias. IMT collected with insect urine were irradiated (150 krad) and used to immunize a BALB/c mouse for hybridoma production. Supernatants were screened by immunofluorescence assay for the presence of IgG MAb that react with methanol-fixed IMT, epimastogotes (EPI) and culture-derived metacyclic trypomastigoes (CMT). Of 41 MAb obtained, 40 reacted with IMT, 37 with EPI and 38 with CMT. Four MAb immunoprecipitated radioiodinated proteins or protein conjugates of M/sub r/ 80, 72, 45 and 45 from lysates of /sup 125/I surface-labeled EPI. These results indicate that, at least at the epitopic level, there is considerable overlap among IMT, EPI and CMT surface antigens. This finding suggests that analysis of surface proteins of the latter 2 parasite forms may lead to identification of molecules useful for vaccine development.

Kirchhoff, L.V.; Gilliam, F.C.

1986-03-05

353

Study of the influence of laser of low potency to label red blood cells and plasmatic protein with 99mTc in vitro  

NASA Astrophysics Data System (ADS)

This work aims to verify the effect of laser of low potency to label red blood cells and plasmatic protein with 99mTc in vitro. The experiments were carried out by incubating of anticoagulant whole blood. Differents doses of gallium arsenide laser with energy density of 3j/cm2, 6j/cm2, 9 j/cm2, 18 j/cm2 and 804nm wavelength was applied. A stannous chloride solution of 1,2?g/mL was added the incubation for 60 minutes. After this the 99mTc was added and the incubation was continued for another 10 minutes. Those were centrifuged, precipitated with thrichoroacetic acid 5% and mensured in a counter. The results shows that there is a significant decrease in the fixation of 99mTc in red blood cells when the concentration of 3j/ cm2 and (from 93 to 32.2%) and in occurs an increase %ATI from 12 to 54,6% of plasma protein. The laser promote modification on some properties of the red blood cellular membrane, probably, due to the metabolization of cellular that could be capable to generation the active metabolites.

Rolim, Ricardo Q.; Carvalho, Elaine F.; Nascimento, Edgar V.; Souza, Grace M.; Magnata, Simey S.; Bernardo-Filho, Mario; Catanho, Maria T.

2004-09-01

354

Hydrogen generator  

SciTech Connect

A gas generator in which the gas is produced by a reaction between a solid metal and a liquid reactant. The generator is operated to produce hydrogen intended as an energy source particularly for operating internal combustion engines. A solid reactant is reacted with a liquid reactant under conditions in which both reactants are moving and continuously maintained under operating conditions. The solid is in the form of metal balls which are conveyed through a reaction chamber on inclined perforate channels. The liquid reactant is sprayed over the moving balls. Waste solid reaction products are removed by the rolling action of the balls on the perforate channels and the washing action of the sprayed liquid reactant. In the production of hydrogen, aluminum metal balls are used and the liquid reactant is a solution of sodium hydroxide. Because the reaction is exothermic, excess heat is removed by cooling the liquid reactant.

Houser, C. F.

1985-09-24

355

Generating functions for generating trees  

Microsoft Academic Search

Certain families of combinatorial objects admit recursive descriptions in terms of gen- erating trees: each node of the tree corresponds to an object, and the branch leading to the node encodes the choices made in the construction of the object. Generating trees lead to a fast computation of enumeration sequences (sometimes, to explicit formulae as well) and provide efficient random

Cyril Banderier; Mireille Bousquet-mélou; Alain Denise; Philippe Flajolet; Daničle Gardy; Dominique Gouyou-beauchamps

2002-01-01

356

Thermoelectric generator  

DOEpatents

A thermoelectric generator having a rigid coupling or stack'' between the heat source and the hot strap joining the thermoelements is described. The stack includes a member of an insulating material, such as ceramic, for electrically isolating the thermoelements from the heat source, and a pair of members of a ductile material, such as gold, one each on each side of the insulating member, to absorb thermal differential expansion stresses in the stack. (Official Gazette)

Pryslak, N.E.

1974-02-26

357

Hydroelectric Generator  

NASA Astrophysics Data System (ADS)

The idea behind a hydro electric generator is to have a large potential well of water that you can be controlled to be able to convert into kinetic energy. The kinetic energy is from the flow of water which is directed towards some kind of turbine. In turn the kinetic energy is turned into mechanical energy. The turning of the turbine rotates the rotor part of the generator, and the stator remains stationary. Induction is caused when the rotor is rotating around the stator. This is caused when a magnetic field interacts with a wire causing the electrons inside the wire to face in the same direction. Once the magnetic field begins to move the electrons start to flow through the wire creating current. For this to work the direction of the magnetic field has to be perpendicular to the direction of the coils of wires. For my design I plan to funnel the flow of water into a nozzle which will be aimed towards my turbine. The turbine with be connected to a shaft that will be connected to my rotor. The rotor I designed uses a brake router for the surface to hold me magnets. The system will be vertical, with the rotor as the highest part on the generator and the turbine at the bottom. The magnets will be facing downwards with the magnetic field going in a vertical direction. The stator of my generator will be the coils which will sit on top of a metal ring that have the ability to rise or low to match the height of the brake router.

Zipprian, Daniel

2012-03-01

358

PLASMA GENERATOR  

DOEpatents

This patent describes apparatus for producing an electricity neutral ionized gas discharge, termed a plasma, substantially free from contamination with neutral gas particles. The plasma generator of the present invention comprises a plasma chamber wherein gas introduced into the chamber is ionized by a radiofrequency source. A magnetic field is used to focus the plasma in line with an exit. This magnetic field cooperates with a differential pressure created across the exit to draw a uniform and uncontaminated plasma from the plasma chamber.

Foster, J.S. Jr.

1958-03-11

359

Tracheal blood flow and luminal clearance of [sup 99m][Tc]-DTPA in sheep  

SciTech Connect

Tracheal blood flow and [sup 99m][Tc]-labeled diethylenetriamine pentaacetic acid (DTPA) clearance were measured in the sheep trachea in vivo. The tracheal arteries were isolated and perfused. An isolated segment of tracheal lumen was filled with Krebs-Henseleit solution containing [sup 99m][Tc]-DTPA, and radioactivity was measured in blood from a catheterized tracheal vein. Infusions at constant pressure of methacholine (n=5), albuterol (n=6), and histamine (n=5) increased arterial inflow and venous outflow but decreased [sup 99m][Tc]-DTPA output and concentration. Phenylephrine (n=9) decreased arterial inflow and venous outflow but increased [sup 99m][Tc]-DTPA output and concentration. When the tracheal arteries were initially perfused at constant flow and the flow rate was then changed, 50% increases in flow (n=5) increased perfusion pressure and venous outflow but decreased [sup 99m][Tc]-DTPA output and concentration. Decreases in flow of 50% (n=3) and 100% (n=10) decreased perfusion pressure and venous outflow but increased [sup 99m][Tc]-DTPA output and concentration. Infusion of the same drugs at constant flow produced significant changes in perfusion pressure but no significant changes in venous outflow or, except for histamine, in [sup 99m][Tc]-DTPA output. Thus [sup 99m][Tc]-DTPA output was inversely related to both mechanically and drug-induced changes in tracheal blood flow but, except for histamine, was not directly affected by the drugs. The results may be due to redistribution of blood between collateral circuits and altered interstitial fluid volume affecting [sup 99m][Tc]-DTPA transport across the interstitium. 24 refs., 6 figs., 3 tabs.

Hanafi, Z.; Corfield, D.R.; Webber, S.E.; Widdicombe, J.G. (St. George's Hospital Medical School, London (United Kingdom))

1992-10-01

360

99mTc(CO)3(NTA): A 99mTc Renal Tracer with Pharmacokinetic Properties Comparable to Those of 131I-OIH in Healthy Volunteers  

PubMed Central

Objectives Studies in rats showed that the pharmacokinetics of the tricarbonyl core radiopharmaceutical 99mTc(CO)3-nitrilotriacetic acid, 99mTc(CO)3(NTA), were essentially identical to those of 131I ortho-iodohippuran (131I-OIH), the clinical gold standard for the measurement of effective renal plasma flow. Our objective was to compare the pharmacokinetics of these two tracers in healthy volunteers. Methods 99mTc(CO)3(NTA) was prepared with commercially available NTA and a commercially available IsoLink kit (Covidien) and isolated by reversed-phased high-performance liquid chromatography. Approximately 74 MBq (2.0 mCi) of 99mTc(CO)3(NTA) were coinjected with 9.25 MBq (250 ?Ci) of 131I-OIH in nine volunteers, and simultaneous imaging of each tracer was performed for 24 min. Plasma clearances were determined from 8 blood samples obtained 3–90 min after injection using the single-injection, two-compartment model. Plasma protein binding, red cell uptake, and percentage injected dose in the urine at 30 and 180 minutes were determined. Results There was no difference in the plasma clearances of 99mTc(CO)3(NTA) and 131I-OIH, 475 ± 105 mL/min versus 472 ± 108 mL/min, respectively. The plasma protein binding and red cell uptake of 99mTc(CO)3(NTA) were 43 ± 5% and 9 ± 6%, respectively; both values were significantly lower (P < 0.001) than the plasma protein binding (75 ± 3%) and red cell uptake (17 ± 5%) of 131I-OIH. There was no significant difference in the percent injected dose recovered in the urine at 30 min and at 3 h; for comparison, the percent dose in the urine at 3 h was 91 ± 4% for 99mTc(CO)3(NTA) and 91 ± 6% for 131I-OIH (P = 0.96). Image quality with 99mTc(CO)3(NTA) was excellent, and the renogram parameters were similar to those of 131I-OIH. Conclusions Preliminary results in healthy volunteers suggest that the pharmacokinetic behavior of 99mTc(CO)3(NTA) is comparable to that of 131I-OIH.

Taylor, Andrew T.; Lipowska, Malgorzata; Marzilli, Luigi G.

2010-01-01

361

Theory of high-TC superconductivity: transition temperature  

NASA Astrophysics Data System (ADS)

After reading over our published manuscript, we noticed that the discussion concerning the determination of ? for the ruthenate Ba2YRu0.9Cu0.1O6 in section 2.3.1 (3rd paragraph) is somewhat terse. Herein we provide an expanded analysis which better explains our estimate of ? (and thus ?) for this compound. All numbers, figures and conclusions remain unaltered. The ruthenate compounds A2YRu1-xCuxO6 (with A = Ba or Sr; x = 0.05-0.15) are double-perovskites containing no cuprate planes and with ? = ? = 1 [1] (reference [82] in the paper). The determination of ? follows from equation (2.5b), wherein rule 1b introduces the factor 1/2. In the lower limit, one expects a minimum of ~2 charges per Cu dopant, which are shared between two charge reservoirs of each layer type (AO and 1/2 (YRu1-xCuxO4)), producing a net factor of unity. Thus, for Ba2YRu0.9Cu0.1O6 (with TC0 ~ 30-40 K), we estimate ? = (1/2)(1) = 1/2, yielding ? = 0.05 as stated by equation (2.5c) in the paper. While one may expect an average effective charge state for Ru near +5, and that of Cu to be between +2 and +3 (post anneal) [2], the lower-limit estimation provided, which places the corresponding data point in figure 2 to the left of the line, appears sufficient to include the ruthenates with the other high-TC compounds found to follow equation (2.6) so far. Owing to the uncertainty in the experimental values for TC0, as well as the Ru and Cu valence states, however, this compound was excluded in the data analyses presented. Future research will attempt a more accurate determination of the charge per doped Cu, and thus ?. We would also like to point out a typographical correction in the definition of the corresponding ruthenate type II reservoir in the last column of table 1, which should read 1/2 (YRu0.9Cu0.1O4). An unrelated item is found in the fourth line of section 2.3.3, where Tb(O0.80F0.20)FeAs should read Tb(O0.80-yF0.20)FeAs. Additionally, reference [132] is now known and has the form: [132] Harshman D R and Fiory A T 2011 J. Phys.: Condens. Matter 23 315702 References [1] Parkinson N G, Hatton P D, Howard J A K, Ritter C, Chien F Z and Wu M-K 2003 J. Mater. Chem. 13 1468 [2] Rao S M, Wu M-K, Ren H C, Chen C L, Guo J-H, Hsu F C, Chen S Y, Chen Y Y, Chang C L and Liu H L 2011 in preparation

Harshman, Dale R.; Fiory, Anthony T.; Dow, John D.

2010-12-01

362

Interdecadal changes in TC activities that affect Korea  

NASA Astrophysics Data System (ADS)

The present study elucidated the fact that remarkable interdecadal variation exists in the time series of the tropical cyclone (TC) frequency that affects Korea during June-October. These variations were identified through statistical change-point analysis, and the results showed that significant variation existed in 1983 and 2004. Therefore, data in 2005 and thereafter were excluded and differences in TC activities during the period after 1983 (1984-2004) and a period before 1983 (1968-1983), as well as differences in large-scale environments were analyzed. During the period of 1984-2004, TCs mainly occurred in the northwest quadrant of the subtropical western North Pacific (SWNP). The TCs move from the east sea of Philippines, pass the East China Sea, recurved, and moved to Korea and Japan. During the period of 1968-1983, TCs occurred in the southeast quadrant of the SWNP and showed a characteristic westward movement from the southeast of Philippines toward the southern coast of China and the Indochina Peninsula. Therefore, the intensity of TCs during the former period, which were supplied with greater heat and water vapor from the sea, were stronger, while TCs during the latter period quickly dissipated after landing in the southern coast of China and the Indochina Peninsula due to the effects of topography. Thus, the lifetimes of the TCs were short and their intensities were weak. The cause of these differences in TC activities between the two periods was identified through differences in stream flows between the 850 hPa level and the 500 hPa level. At the 850 hPa level, anomalous cyclonic (anticyclonic) circulations are reinforced in most waters north (south) to 10° N, and thus, more (fewer) TCs occur in the northwest (southeast) quadrant of the SWNP during the period of 1984-2004 (1968-2003). At the 500 hPa level, since the center of anomalous cyclonic circulation is located in the southeastern region of China southeast to the east sea of the Philippines, anomalous southerlies from the east sea of Philippines to Korea and Japan are predominant. Due to the anomalous steering flows of these anomalous southerlies, the TCs during the period of 1984-2004 show the aforementioned paths. On the other hand, anomalous northerlies or northeasterlies are reinforced in regions in the west of the center of these anomalous cyclonic circulations, and thus, these anomalous steering flows serve the role of preventing TCs from moving toward the southern coast of China the Indochina Peninsula during the period of 1984-2004. During the period of 1984-2004, vertical wind shears and sea surface temperatures are high and low, respectively, in most waters of the SWNP. Therefore, more TCs occur and are reinforced during this period.

Choi, Ki-Seon; Cha, Yu-Mi; Kang, Sung-Dae; Kim, Hae-Dong

2013-07-01

363

Identification of ataxia-associated mtDNA mutations (m.4052T>C and m.9035T>C) and evaluation of their pathogenicity in transmitochondrial cybrids.  

PubMed

The potential pathogenicity of two homoplasmic mtDNA point mutations, 9035T>C and 4452T>C, found in a family afflicted with maternally transmitted cognitive developmental delay, learning disability, and progressive ataxia was evaluated using transmitochondrial cybrids. We confirmed that the 4452T>C transition in tRNA(Met) represented a polymorphism; however, 9035T>C conversion in the ATP6 gene was responsible for a defective F(0)-ATPase. Accordingly, mutant cybrids had a reduced oligomycin-sensitive ATP hydrolyzing activity. They had less than half of the steady-state content of ATP and nearly an 8-fold higher basal level of reactive oxygen species (ROS). Mutant cybrids were unable to cope with additional insults, i.e., glucose deprivation or tertiary-butyl hydroperoxide, and they succumbed to either apoptotic or necrotic cell death. Both of these outcomes were prevented by the antioxidants CoQ(10) and vitamin E, suggesting that the abnormally high levels of ROS were the triggers of cell death. In conclusion, the principal metabolic defects, i.e., energy deficiency and ROS burden, resulted from the 9035T>C mutation and could be responsible for the development of clinical symptoms in this family. Furthermore, antioxidant therapy might prove helpful in the management of this disease. PMID:19626676

Sikorska, Marianna; Sandhu, Jagdeep K; Simon, David K; Pathiraja, Vimukthi; Sodja, Caroline; Li, Yan; Ribecco-Lutkiewicz, Maria; Lanthier, Patricia; Borowy-Borowski, Henryk; Upton, Adrian; Raha, Sandeep; Pulst, Stefan M; Tarnopolsky, Mark A

2009-09-01

364

Occurrence of two genotypes of tetracycline (TC) resistance gene tet(M) in the TC-resistant bacteria in marine sediments of Japan.  

PubMed

The tetracycline (TC) resistance gene tet(M) was monitored in bacteria isolated from Japanese coastal and off-shore marine sediments. The high rate of occurrence of TC resistant (TC(r)) bacteria (120 microg mL(-1) TC) was observed at frequency ranges between 0.0-0.08% in Tokyo Bay, 1.67-1.82% in Sagami Bay and 0.0-4.35% in the open Pacific Ocean. The tet(M) gene was PCR amplified from the TC(r) isolates, showing 127 of 209 isolates (60.8%) as positive. The rate of occurrence of tet(M) was between 32.0-96.0%, 21.1 -28.0% and 0.0-83.3% in the isolates from Tokyo Bay, Sagami Bay and the open Pacific Ocean, respectively. The tet(M) positive isolates belonged to 4 orders of bacteria. Bacillales was the most dominant order (121 strains) among tet(M) possessing bacteria, followed by Actinomycetales (three strains), Flavobacteriales (one strain) and Pseudomonadales (one strain). This indicates that tet(M) is present in various bacterial species and suggests that marine sediments are a natural reservoir of the tet(M) gene. Nucleotide sequence of the tet(M) revealed that two genotypes of tet(M) were found in the bacteria. The two genotypes were placed in genetically distant branches of the phylogenetic tree, suggesting that the two tet(M)s have different origins. PMID:18754347

Rahman, M Habibur; Nonaka, Lisa; Tago, Ryosuke; Suzuki, Satoru

2008-07-15

365

Foam as a Delivery Vehicle in Vadose Zone Remediation: Transport; Amendment Distribution; and Tc-99 Immobilization  

NASA Astrophysics Data System (ADS)

Foam is a promising low water content advection technology for the distribution of remedial amendments to the deep vadose zone for metals and radionuclides remediation. Foam flow in the vadose zone can be directed by manipulating the pressure field, therefore the foam delivery technology allows more even distribution of remedial amendments under vadose zone conditions than water-based delivery. With minimal water content in foam flow, foam delivery minimizes the potential for contaminant mobilization and spreading. Laboratory scale experiments were conducted to investigate the physical aspects of foam transport in sediments under vadose zone conditions, to study the (poly)phosphate amendment foam-delivery; and to evaluate technetium-99 immobilization by foam-delivered calcium polysulfide. Foam quality (percentage of gas volume in total foam volume) between 95% and 99% was tested to study its influence on foam injection pressure. It was observed that the injection pressure increased inversely as a function of foam quality. The effect of sediment permeability on foam injection pressure was evaluated in sediments with a range of permeabilities. Results suggested that when the foam injection rate was low, the injection pressure increased with sediment permeability; but when the foam injection rate was high, the injection pressure versus permeability relationship was reversed. Foam bubbles rupture at the foam-flow-front in the unsaturated sediments. The front of the gas injected with foam traveled significantly faster (~ 8 times) than the foam front observed in the sediment. The liquid carried by foam was left behind the foam front. In addition a water accumulation front developed in sediment ahead of the foam-flow-front, i.e. sediment not swept by foam flow, as native pore water was displaced by the foam front. The water content in this liquid accumulation front increased with the increasing of initial water content in the sediment. However, the water content in the sediment swept by foam flow was negligibly affected by the initial water content. Very low surfactant concentration was observed in the accumulated liquid ahead of the foam front, indicating the initial moisture in the sediment was pushed forward by foam flow. In the foam-delivery of (poly)phosphate column tests, the delivery of phosphate was retarded slightly compare to the foam front and the distribution of surfactant in the sediment. The profile of pore water electric conductivity was similar to the phosphate distribution profile. Immobilization of Tc-99 by foam-delivered calcium polysulfide (CPS) in sediments under vadose zone conditions was evaluated. Foams generated from 0.5 wt% STEOL CS-330 surfactant solution at quality of 98% was used to deliver CPS sediment in columns for reductive immobilization of Tc-99. The foaming solution contained 5 wt% of calcium polysulfide. Using the foam-delivered calcium polysulfide, 66% of the total Tc-99 in the contaminated sediment was immobilized in the sediment. No technetium remobilization was observed when up to 6 pore volume of synthetic ground water was flushed through the treated sediment column.

Zhong, L.; Szecsody, J.; Wellman, D. M.; Zhang, Z. F.; Mattigod, S.; Pierce, E. M.

2009-12-01

366

Determination of 99 Tc-DPD complex composition and valence states of technetium  

Microsoft Academic Search

DPD (2,3-dicarboxypropane-1,1-diphosphonic acid) forms two complexes with99Tc, previously reduced by Sn(II): with max at 410 nm (pH 3–7), and at 515 nm (pH 5–9.6). By Job's method, formation of complexes with DPD:Tc molar ratios of 21 and 23 was found in acidic medium (pH=3). In order to determine the valence states of Tc in the complex, taking into account that

N. Vanli?-Razumeni?; V. Nikoli?; D. Veselinovi?

1993-01-01

367

Tight relation between the oxygen deficiency and Tc in LaFeAsO1-?  

NASA Astrophysics Data System (ADS)

Oxygen vacant superconductors LaFeAsO1-? were synthesized under a high-pressure condition. A bell-shaped feature in Tc vs. ? was observed for LaFeAsO1-? as well as TbFeAsO1-?. The optimized Tc was achieved at ? of 0.15, being comparable with that for TbFeAsO1-?. The relatively wide ? window of LaFeAsO1-? may merit scientific and technical studies of high-Tc superconductivity.

Guo, Y. F.; Shi, Y. G.; Yu, S.; Belik, A. A.; Matsushita, Y.; Tanaka, M.; Katsuya, Y.; Kobayashi, K.; Hata, Y.; Yasuoka, H.; Yamaura, K.; Takayama-Muromachi, E.

2010-12-01

368

Reverse redistribution of Tc99m-tetrofosmin in patients with acute myocardial infarction  

Microsoft Academic Search

We examined reverse redistribution (RR) of Tc-99m-tetrofosmin after a single injection in patients with acute myocardial infarction\\u000a (AMI). Tc-99m-tetrofosmin myocardial SPECT was performed in 28 patients with AMI 10–14 days after the onset. Myocardial images\\u000a were obtained 30 min and 180 min after the injection of 740 MBq of Tc-99m-tetrofosmin. The left ventricular wall was divided\\u000a into 9 segments. Regional

Hiroki Sugihara; Tatsuya Nakagawa; Eiko Yamashita; Noriyuki Kinoshita; Kazuki Ito; Akihiro Azuma; Chio Okuyama; Yo Ushijima; Masao Nakagawa; Tomoho Maeda

1999-01-01

369

Evaluation of brain tumor recurrence by 99m Tc-tetrofosmin SPECT: a prospective pilot study  

Microsoft Academic Search

Objective  The differentiation between brain tumor recurrence and post-irradiation injury remains an imaging challenge. Computed tomography\\u000a (CT) and magnetic resonance imaging (MRI) cannot always distinguish between the two. Although glioma cell line studies substantiated\\u000a a plausible imaging superiority of 99mTc-tetrofosmin (99mTc-TF) over other radiopharmaceuticals, little has been reported on its in vivo imaging properties. We assessed 99mTc-TF single-photon emission CT (SPECT)

George A. Alexiou; Andreas D. Fotopoulos; Athanasios Papadopoulos; Athanasios P. Kyritsis; Konstantinos S. Polyzoidis; Spyridon Tsiouris

2007-01-01

370

Quantum-limit linkage of 'strange' and conventional metal states of high-Tc superconductors  

NASA Astrophysics Data System (ADS)

The key to the nature of superconducting pairing in high-Tc cuprates lies in understanding the transition to a conventional behavior when they are heavily doped. By using high magnetic fields, we show that the pseudogapped Tl2Ba2CuO6+x becomes a conventional metal at heavy doping in a quantum phase transition, where the pseudogap boundary develops a thermodynamic divergence corresponding to a zero entropy jump. The critical doping point downshifts with magnetic field in unison with the suppression of Tc. This implies that quantum critical fluctuations and magnetic degrees that destabilize the pseudogap are linked to the superconductivity with high Tc.

Krusin-Elbaum, L.; Shibauchi, T.; Kasahara, Y.; Okazaki, R.; Matsuda, Y.; McDonald, R. D.; Mielke, C. H.; Hasegawa, M.

2013-10-01

371

The PCP/PFP programming models on the BBN TC2000  

SciTech Connect

We describe the PCP/PFP programming models which we are using on the BBN TC2000. The parallel programming models are implemented in a portable manner and will be useful on the scalable shared memory machines we expect to see in the future. We then describe the TC2000 machine architecture which is a scalable general purpose parallel architecture capable of efficiently supporting both shared memory and message passing programming paradigms. We also briefly describe a PCP implementation of the Gauss elimination algorithm which exploits the large local memories on the TC2000.

Brooks, E.D. III; Gorda, B.C.; Warren, K.H.

1991-03-01

372

Experimental Study of [99mTc(PNP5) (DBODC)]+ as a New Myocardial Perfusion Imaging Agent  

Microsoft Academic Search

Objectives: This study was aimed to compare the properties of [99mTc(PNP5)(DBODC)]+ with 99mTc-MIBI in normal swine and in canine models of myocardial ischemia. Methods: Seven anesthetized swine were injected intravenously with [99mTc(PNP5)(DBODC)]+. Serial planar images were acquired meanwhile. Twelve adult dogs were studied. A critical stenosis of left anterior descending artery was produced. [99mTc(PNP5)(DBODC)]+ or 99mTc-MIBI (randomly) was injected intravenously

Wan-Chun Zhang; Wei Fang; Bin Li; Xue-Bin Wang; Zuo-Xiang He

2009-01-01

373

Fast Monte Carlo based joint iterative reconstruction for simultaneous {sup 99m}Tc/{sup 123}I SPECT imaging  

SciTech Connect

Simultaneous {sup 99m}Tc/{sup 123}I SPECT allows the assessment of two physiological functions under identical conditions. The separation of these radionuclides is difficult, however, because their energies are close. Most energy-window-based scatter correction methods do not fully model either physical factors or patient-specific activity and attenuation distributions. We have developed a fast Monte Carlo (MC) simulation-based multiple-radionuclide and multiple-energy joint ordered-subset expectation-maximization (JOSEM) iterative reconstruction algorithm, MC-JOSEM. MC-JOSEM simultaneously corrects for scatter and cross talk as well as detector response within the reconstruction algorithm. We evaluated MC-JOSEM for simultaneous brain profusion ({sup 99m}Tc-HMPAO) and neurotransmission ({sup 123}I-altropane) SPECT. MC simulations of {sup 99m}Tc and {sup 123}I studies were generated separately and then combined to mimic simultaneous {sup 99m}Tc/{sup 123}I SPECT. All the details of photon transport through the brain, the collimator, and detector, including Compton and coherent scatter, septal penetration, and backscatter from components behind the crystal, were modeled. We reconstructed images from simultaneous dual-radionuclide projections in three ways. First, we reconstructed the photopeak-energy-window projections (with an asymmetric energy window for {sup 123}I) using the standard ordered-subsets expectation-maximization algorithm (NSC-OSEM). Second, we used standard OSEM to reconstruct {sup 99m}Tc photopeak-energy-window projections, while including an estimate of scatter from a Compton-scatter energy window (SC-OSEM). Third, we jointly reconstructed both {sup 99m}Tc and {sup 123}I images using projection data associated with two photopeak energy windows and an intermediate-energy window using MC-JOSEM. For 15 iterations of reconstruction, the bias and standard deviation of {sup 99m}Tc activity estimates in several brain structures were calculated for NSC-OSEM, SC-OSEM, and MC-JOSEM, using images reconstructed from primary (unscattered) photons as a reference. Similar calculations were performed for {sup 123}I images for NSC-OSEM and MC-JOSEM. For {sup 123}I images, dopamine binding potential (BP) at equilibrium and its signal-to-noise ratio (SNR) were also calculated. Our results demonstrate that MC-JOSEM performs better than NSC- and SC-OSEM for quantitation tasks. After 15 iterations of reconstruction, the relative bias of {sup 99m}Tc activity estimates in the thalamus, striata, white matter, and gray matter volumes from MC-JOSEM ranged from -2.4% to 1.2%, while the same estimates for NSC-OSEM (SC-OSEM) ranged from 20.8% to 103.6% (7.2% to 41.9%). Similarly, the relative bias of {sup 123}I activity estimates from 15 iterations of MC-JOSEM in the striata and background ranged from -1.4% to 2.9%, while the same estimates for NSC-OSEM ranged from 1.6% to 10.0%. The relative standard deviation of {sup 99m}Tc activity estimates from MC-JOSEM ranged from 1.1% to 4.8% versus 1.2% to 6.7% (1.2% to 5.9%) for NSC-OSEM (SC-OSEM). The relative standard deviation of {sup 123}I activity estimates using MC-JOSEM ranged from 1.1% to 1.9% versus 1.5% to 2.7% for NSC-OSEM. Using the {sup 123}I dopamine BP obtained from the reconstruction produced by primary photons as a reference, the result for MC-JOSEM was 50.5% closer to the reference than that of NSC-OSEM after 15 iterations. The SNR for dopamine BP was 23.6 for MC-JOSEM as compared to 18.3 for NSC-OSEM.

Ouyang Jinsong; El Fakhri, Georges; Moore, Stephen C. [Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115 (United States)

2007-08-15

374

Prevention of Graft Rejection by Donor Type II CD8+ T Cells (Tc2 Cells) Is Not Sufficient to Improve Engraftment in Fetal Transplantation  

PubMed Central

Objectives: Tc2 cells, a subset of CD8+ T cells, are able to facilitate engraftment in a murine model of postnatal allogeneic bone marrow transplantation. The purpose of this study was to evaluate whether Tc2 cells could improve engraftment in fetal transplantation. Methods: Gestational day 13 C57BL/6 (H-2b) fetal mice were used as recipients, adult B6D2F1 mice (C57BL/6 × DBA/2,H-2b/d) as donors, and splenocytes from B6C3F1 (C57BL/6 × C3H/He, H-2b/k) mice were used as stimulators in cultures used to generate the Tc2 cells from B6D2F1 mice Peripheral blood chimerism was examined monthly for 3 months. Thereafter, recipients were sacrificed to evaluate the levels of peritoneal, splenic and bone marrow chimerism. The T-cell responses of recipient splenocytes to cells of host origin were measured as a proliferative response in mixed lymphocyte cultures. Results: Low levels of peripheral blood cell chimerism (<0.3%) were observed at 1 month of age, which declined further by 3 months of age. The levels of donor cells in the spleen, bone marrow and peritoneal cavity were usually not more than 0.05%. The peritoneal cavity tended to have higher levels of donor cells with 1 recipient sustaining as high as 25.03% at the age of 3 months. Higher peritoneal chimerism correlated with a lower donor-specific T-cell response. Conclusions: Transplantation of Tc2 cells was insufficient to improve bone marrow engraftment in utero, suggesting that graft rejection is not the major barrier to successful in utero transplantation. Donor cells can persist in the peritoneal cavity and might play an important role in inducing immune tolerance in fetuses.

Chen, Jeng-Chang; Chang, Ming-Ling; Lee, Hanmin; Muench, Marcus O.

2005-01-01

375

Sustained neuronal activity generated by glial plasticity.  

PubMed

Astrocytes release gliotransmitters, notably glutamate, that can affect neuronal and synaptic activity. In particular, astrocytic glutamate release results in the generation of NMDA receptor (NMDA-R)-mediated slow inward currents (SICs) in neurons. However, factors underlying the emergence of SICs and their physiological roles are essentially unknown. Here we show that, in acute slices of rat somatosensory thalamus, stimulation of lemniscal or cortical afferents results in a sustained increase of SICs in thalamocortical (TC) neurons that outlasts the duration of the stimulus by 1 h. This long-term enhancement of astrocytic glutamate release is induced by group I metabotropic glutamate receptors and is dependent on astrocytic intracellular calcium. Neuronal SICs are mediated by extrasynaptic NR2B subunit-containing NMDA-Rs and are capable of eliciting bursts. These are distinct from T-type Ca(2+) channel-dependent bursts of action potentials and are synchronized in neighboring TC neurons. These findings describe a previously unrecognized form of excitatory, nonsynaptic plasticity in the CNS that feeds forward to generate local neuronal firing long after stimulus termination. PMID:21613477

Pirttimaki, Tiina M; Hall, Stephen D; Parri, H Rheinallt

2011-05-25

376

Sustained neuronal activity generated by glial plasticity  

PubMed Central

Astrocytes release gliotransmitters, notably glutamate, that can affect neuronal and synaptic activity. In particular, astrocytic glutamate release results in the generation of N-methyl D-aspartate receptor (NMDA-R) mediated slow inward currents (SICs) in neurons. However, factors underlying the emergence of SICs, and their physiological roles are largely unknown. Here we show that, in acute slices of rat somatosensory thalamus, stimulation of Lemniscal or cortical afferents results in a sustained increase of SICs in thalamocortical (TC) neurons that outlasts the duration of the stimulus by an hour. This long term enhancement (LTE) of astrocytic glutamate release is induced by group I metabotropic glutamate receptors (mGluRs), and is dependent on astrocytic intracellular calcium ([Ca2+]i). Neuronal SICs are mediated by extrasynaptic NR2B subunit-containing NMDA-Rs and are capable of eliciting bursts. These are distinct from T-type Ca2+ channel dependent bursts of action potentials, and are synchronized in neighboring TC neurons. These findings describe a previously unrecognized form of excitatory, non-synaptic plasticity in the central nervous system (CNS) that feeds forward to generate local neuronal firing long after stimulus termination.

Pirttimaki, Tiina M.; Hall, Stephen D.; Parri, H. Rheinallt

2011-01-01

377

Phase Equilibria Relationships of High-Tc Superconductors  

SciTech Connect

As an integral part of a R&D program partially supported by the Electricity Delivery and Energy Reliability Office of DOE, we have determined phase equilibria data and phase diagrams for the three generations of superconductor materials: 1st generation, (Bi,Pb)-Sr-Ca- Cu-O systems; 2nd generation, Ba-R-Cu-O systems (R=lanthanides and yttrium); and 3rd generation, MgB2 systems. Our studies involved bulk materials, single crystals and thin films. This report gives a summary of our accomplishments, a list of publications, and 15 selected journal publications

Winnie Wong-Ng

2011-01-11

378

Multiorbital analysis of the effects of uniaxial and hydrostatic pressure on Tc in the single-layered cuprate superconductors  

NASA Astrophysics Data System (ADS)

The origin of uniaxial and hydrostatic pressure effects on Tc in the single-layered cuprate superconductors is theoretically explored. A two-orbital model, derived from first principles and analyzed with the fluctuation exchange approximation gives axial-dependent pressure coefficients ?Tc/?Pa>0, ?Tc/?Pc<0, with a hydrostatic response ?Tc/?P>0 for both La214 and Hg1201 cuprates, in qualitative agreement with experiments. Physically, this is shown to come from a unified picture in which higher Tc is achieved with an “orbital distillation,” namely, the less the dx2-y2 main band is hybridized with the dz2 and 4s orbitals the higher the Tc. Some implications for obtaining higher Tc materials are discussed.

Sakakibara, Hirofumi; Suzuki, Katsuhiro; Usui, Hidetomo; Kuroki, Kazuhiko; Arita, Ryotaro; Scalapino, Douglas J.; Aoki, Hideo

2012-10-01

379

Fabrication of oxocuprate superconductor microelectrodes for sub-{Tc} use  

SciTech Connect

The technique of partial resin encapsulation is described for the direct fabrication of cryorobust oxocuprate microelectrodes from bulk ceramic samples, here Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}}, Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10{minus}{delta}}. Cyclic voltammetry is used in tests of the electrochemical response at 295 K (ferrocene in acetonitrile/NBu{sub 4}BF{sub 4}), affording approximated disk radii 2.9, 37.0, and 32.5 {micro}m, and at 123 and at 103 K (ferrocene in chloroethane/tetrahydrofuran/LiBF{sub 4}). Some nonideality in the 295 K responses results from electrode porosity and, at the smallest electrodes, defects in the HTSC/resin seal. Acceptable sub-T{sub c} responses show these problems to be irrelevant in the high viscosity of the electrolytes at low temperature. These microelectrodes usefully advance the emerging study of electrochemistry on superconducting electrodes by responding to free-solute electroactives at <{Tc}.

Green, S.J.; Rosseinsky, D.R.; Toohey, M.J. [The University, Exeter (United Kingdom). Dept. of Chemistry

1995-07-01

380

Astrometric and photometric studies of the asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

Near real time astrometric and photometric observations of the asteroid 2008 TC3, discovered 19 hours before it fell to Earth in the area of northern Sudan, were conducted on the night of October 6-7, 2008, using an automated telescope ZA-320M of the Pulkovo Observatory. In the interval of 4 h, 270 observations in the integral band of the telescope were performed, which was about one-third of all global observations of the asteroid. Based on the analysis of all cases, physical parameters of the asteroid were assessed. The estimates of the absolute magnitude of the asteroid ( M V = 30.6 ± 0.4 ?m), its size (4.8 ± 0.8 m), and weight (131 ± 5 t) were obtained. A frequency analysis of the observational series was conducted, which helped to detect the periodicity in the brightness variation of the asteroid. The elements of the heliocentric orbit of the asteroid were refined. The trajectory of the asteroid, taking into account the atmospheric drag and nonsphericity of the Earth, was simulated.

Aleshkina, E. Y.; Kupriyanov, V. V.; Devyatkin, A. V.; Vereshchagina, I. A.; Slesarenko, V. Yu.; L'Vov, V. N.; Tsekmeyster, S. D.

2011-02-01

381

High-Tc SQUID Magnetometers for Industrial Applications  

NASA Astrophysics Data System (ADS)

We have developed high-Tc SQUID magnetometers for use in a variety of industrial applications. Relatively inexpensive direct-coupled magnetometers have been developed for low-frequency applications including fetal-magnetocardiography. A manufacturable process has been developed to reproducibly fabricate high-resistance (up to 6 ?) SNS step-edge junctions with YBa_2Cu_3O_7-x as the superconductor and Ag-Au alloy as the normal metal. Magnetic field sensitivities at 77K of 22 ft/Hz^1/2 at 1 KHz and 32 ft/Hz^1/2 at 1 Hz have been achieved in a well-shielded laboratory environment. Current effort is focused on operation in an unshielded environment using flux dams(Milliken et al. Appl. Phys. Lett. 71 1857 (1997)) in conjunction with narrow superconducting pickup coils placed in parallel. An integrated magnetometer process has also been optimized for use in high-frequency applications. The integrated megnetometer utilizes two layers of YBa_2Cu_3O_7-x and one layer of deposited SrTiO_3, all on the same 24 mm x 5 mm substrate. The applications under development include the detection of the explosive material in non-metallic land mines using nuclear quadrupole resonance as well as the non-destructive evaluation of non-metallic composites using nuclear magnetic resonance. For operation in the MHz regime, these applications demand a high quality insulator layer and a robust SQUID that can withstand high current transients.

Diiorio, Mark; Yang, Kai-Yueh; Yoshizumi, Shozo; Haupt, Steven; Haran, Don; Koch, Roger; Lathrop, Dan; Trammel, Hoke

1998-03-01

382

High-Tc SQUID gradiometer system for immunoassays  

NASA Astrophysics Data System (ADS)

A high-Tc dc SQUID (superconducting quantum interference device) gradiometer was developed for magnetic immunoassays where magnetic nanoparticles are used as markers to detect biological reactions. The gradiometer was fabricated on a 5 × 10 mm2 SrTiO3 bicrystal substrate and has a gradiometer resolution of 2.1 pT cm-1 Hz-1/2. A magnetic signal was detected from a sample of 1 µl of Fe3O4 nanoparticles in a 40 mg ml-1 solution kept in a microcavity fabricated on Si wafers with Si3N4 membranes using MEMS (micro-electro-mechanical-systems) technology. It was found that volumes as small as 0.3 nl in principle would be detectable with our present device. This corresponds to a total number of particles of 2.2 × 107. The estimated average dipole moment per particle is 4.8 × 10-22 A m2. We are aiming at reading out immunoassays by detecting the Brownian relaxation of magnetic nanoparticles, and we also intend to integrate MEMS technology into our system.

Öisjöen, F.; Magnelind, P.; Kalabukhov, A.; Winkler, D.

2008-03-01

383

The impact and recovery of asteroid 2008 TC(3).  

PubMed

In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554-995 nm wavelength range, and designated 2008 TC(3) (refs 4-6). It subsequently hit the Earth. Because it exploded at 37 km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95 kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections. PMID:19325630

Jenniskens, P; Shaddad, M H; Numan, D; Elsir, S; Kudoda, A M; Zolensky, M E; Le, L; Robinson, G A; Friedrich, J M; Rumble, D; Steele, A; Chesley, S R; Fitzsimmons, A; Duddy, S; Hsieh, H H; Ramsay, G; Brown, P G; Edwards, W N; Tagliaferri, E; Boslough, M B; Spalding, R E; Dantowitz, R; Kozubal, M; Pravec, P; Borovicka, J; Charvat, Z; Vaubaillon, J; Kuiper, J; Albers, J; Bishop, J L; Mancinelli, R L; Sandford, S A; Milam, S N; Nuevo, M; Worden, S P

2009-03-26

384

Optical symmetries and anisotropic transport in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

A simple symmetry analysis of in-plane and out-of-plane transport in a family of high temperature superconductors is presented. It is shown that generalized scaling relations exist between the low frequency electronic Raman response and the low frequency in-plane and out-of-plane conductivities in both the normal and superconducting states of the cuprates. Specifically, for both the normal and superconducting state, the temperature dependence of the low frequency B_1g Raman slope scales with the c-axis conductivity, while the B_2g Raman slope scales with the in-plane conductivity. Comparison with experiments in the normal state of Bi-2212 and Y-123 imply that the nodal transport is largely doping independent and metallic, while transport near the BZ axes is governed by a quantum critical point near doping p ˜ 0.22 holes per CuO2 plaquette. Important differences for La-214 are discussed. It is also shown that the c- axis conductivity rise for T? Tc is a consequence of partial conservation of in-plane momentum for out-of-plane transport.

Devereaux, Thomas

2004-03-01

385

Optical symmetries and anisotropic transport in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

A simple symmetry analysis of in-plane and out-of-plane transport in a family of high-temperature superconductors is presented. It is shown that generalized scaling relations exist between the low-frequency electronic Raman response and the low-frequency in-plane and out-of-plane conductivities in both normal and superconducting states of the cuprates. Specifically, for both normal and superconducting states, the temperature dependence of the low-frequency B1g Raman slope scales with the c-axis conductivity, while the B2g Raman slope scales with the in-plane conductivity. Comparison with experiments in the normal states of Bi-2212 and Y-123 implies that the nodal transport is largely doping independent and metallic, while transport near the Brillouin Zone axes is governed by a quantum critical point near doping p˜0.22 holes per CuO2 plaquette. Important differences for La-214 are discussed. It is also shown that the c-axis conductivity rise for T?Tc is a consequence of partial conservation of in-plane momentum for out-of-plane transport.

Devereaux, T. P.

2003-09-01

386

Bone turnover markers are correlated with total skeletal uptake of 99mTc-methylene diphosphonate (99mTc-MDP)  

PubMed Central

Background Skeletal uptake of 99mTc labelled methylene diphosphonate (99mTc-MDP) is used for producing images of pathological bone uptake due to its incorporation to the sites of active bone turnover. This study was done to validate bone turnover markers using total skeletal uptake (TSU) of 99mTc-MDP. Methods 22 postmenopausal women (52–80 years) volunteered to participate. Scintigraphy was performed by injecting 520 MBq of 99mTc-MDP and taking whole body images after 3 minutes, and 5 hours. TSU was calculated from these two images by taking into account the urinary loss and soft tissue uptake. Bone turnover markers used were bone specific alkaline phosphatase (S-Bone ALP), three different assays for serum osteocalcin (OC), tartrate resistant acid phosphatase 5b (S-TRACP5b), serum C-terminal cross-linked telopeptides of type I collagen (S-CTX-I) and three assays for urinary osteocalcin (U-OC). Results The median TSU of 99mTc-MDP was 23% of the administered activity. All bone turnover markers were significantly correlated with TSU with r-values from 0.52 (p = 0.013) to 0.90 (p < 0.001). The two resorption markers had numerically higher correlations (S-TRACP5b r = 0.90, S-CTX-I r = 0.80) than the formation markers (S-Total OC r = 0.72, S-Bone ALP r = 0.66), but the difference was not statistically significant. TSU did not correlate with age, weight, body mass index or bone mineral density. Conclusion In conclusion, bone turnover markers are strongly correlated with total skeletal uptake of 99mTc-MDP. There were no significant differences in correlations for bone formation and resorption markers. This should be due to the coupling between formation and resorption.

Lenora, Janaka; Norrgren, Kristina; Thorsson, Ola; Wollmer, Per; Obrant, Karl J; Ivaska, Kaisa K

2009-01-01

387

Impact of Bidentate Chelators on Lipophilicity, Stability and Biodistribution Characteristics of Cationic 99mTc-Nitrido Complexes  

PubMed Central

This report describes synthesis and evaluation of novel cationic 99mTc-nitrido complexes, [99mTcN(L)(PNP)]+ (L = ma, ema, tma, etma and mpo; PNP = PNP5, PNP6 and L6), as potential radiotracers for heart imaging. Cationic complexes [99mTcN(L)(PNP)]+ were prepared in two steps. For example, reaction of succinic dihydrazide with 99mTcO4? in the presence of excess stannous chloride and PDTA resulted in the [99mTcN(PDTA)n] intermediate, which then reacted Hmpo and PNP6 at 100 °C for 10 – 15 min to give [99mTcN(mpo)(PNP6)]+ in >90% yield. It was found that bidentate chelators have a significant impact on lipophilicity, solution stability, biodistribution and metabolic stability of cationic 99mTc-nitrido complexes. The fact that [99mTcN(ema)(PNP6)]+ decomposes rapidly in presence of cysteine (1 mg/mL) while [99mTcN(etma)(PNP6)]+ and [99mTcN(mpo)(PNP6)]+ remain stable for >6 h under the same conditions strongly suggests that thione-S donors in bidentate chelators increase the solution stability of their cationic 99mTc-nitrido complexes. Biodistribution studies were performed on four cationic 99mTc-nitrido complexes in Sprague-Dawley rats. [99mTcN(etma)(PNP5)]+ is of particular interest due to its high initial heart uptake (1.81±0.35 %ID/g at 5 min postinjection), and long myocardial retention (1.99±0.47 %ID/g at 120 min postinjection). The heart/liver ratio of [99mTcN(etma)(PNP5)]+ (6.06±1.48) at 30 min postinjection is almost identical that of 99mTcN-DBODC5 (6.01±1.45), and is >2 times better than that of 99mTc-sestamibi (2.90±0.22). Results from metabolism studies show that [99mTcN(etma)(PNP5)]+ has no significant metabolism in the urine; but it does show significant metabolism in feces samples at 120 min postinjection. Planar imaging studies suggest that [99mTcN(etma)(PNP5)]+ might be able to give clinically useful images of the heart as early as 30 min postinjection. [99mTcN(etma)(PNP5)]+ is a very promising candidate for more pre-clinical evaluations in various animal models.

Liu, Shuang; He, Zhengjie; Hsieh, Wen-Yuan; Kim, Yong-Seung

2008-01-01

388

Increased bone marrow uptake on Tc-99m DMSA scintigraphy in a patient with renal osteodystrophy.  

PubMed

A 16-year-old male patient was evaluated with Tc-99m Diethylenetriamine-pentaacetic acid (DTPA) and Tc-99m 2-3 Dimercaptosuccinic acid (DMSA) scintigraphy for renal failure secondary to renal calculi. The uptake in the renal cortex was significantly decreased both on DMSA and DTPA studies. Uptake calculation on DMSA scintigraphy in the kidneys disclosed values of less than 5%. The activity in the liver and bone was significantly increased. A bone scan performed with Tc-99m methylene diphosphonate (MDP) revealed increased bone uptake with decreased soft tissue activity. Findings on bone scan were compatible with super scan, most likely due to renal osteodystrophy. This case illustrates the altered biodistribution of Tc-99m DMSA and a shift of the radiopharmaceutical to the bone marrow which is not likely related to colloid formation due to changes in mineral balance in patients with renal failure. PMID:8292457

Caglar, M; Naldöken, S

1993-11-01

389

Thermo-Hydro-Mechanical Coupled Modeling: Big-Ben Experiment, TC3. DECOVALEX-Phase 3.  

National Technical Information Service (NTIS)

The report presents results of a finite element analysis for one of the test case (TC) problems identified for modeling during Phase III activities of the international cooperative project DECOVALEX (acronym for the DEvelopment of COupled models and their...

M. P. Ahola G. I. Ofoegbu A. H. Chowdhury S. M. Hsiung

1994-01-01

390

Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)  

NASA Astrophysics Data System (ADS)

99Technetium ( 99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life ( t1/2 = 2.13 × 10 5 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron, either in aqueous form (Fe 2+) or in mineral form [Fe(II)], has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) has not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Surface Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total structural Fe content of these clay minerals, after surface Fe-oxide removal, ranged from 0.7% to 30.4% by weight, and the structural Fe(III)/Fe(total) ratio ranged from 45% to 98%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with structural Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella putrefaciens CN32 cells as a mediator. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. In the S-I series, smectite (montmorillonite) was the most reducible (18% and 41% without and with AQDS, respectively) and illite the least (1% for both without and with AQDS). The extent and initial rate of bioreduction were positively correlated with the percent smectite in the S-I series (i.e., layer expandability). Fe(II) in the bioreduced clay minerals subsequently was used to reduce Tc(VII) to Tc(IV) in PIPES buffer. Similar to the trend of bioreduction, in the S-I series, reduced NAu-2 showed the highest reactivity toward Tc(VII), and reduced illite exhibited the least. The initial rate of Tc(VII) reduction, after normalization to clay and Fe(II) concentrations, was positively correlated with the percent smectite in the S-I series. Fe(II) in chlorite and palygorskite was also reactive toward Tc(VII) reduction. These data demonstrate that crystal chemical parameters (layer expandability, Fe and Fe(II) contents, and surface area, etc.) play important roles in controlling the extent and rate of bioreduction and the reactivity toward Tc(VII) reduction. Reduced Tc(IV) resides within clay mineral matrix, and this association could minimize any potential of reoxidation over long term.

Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

2011-09-01

391

Tc-99m Labeled and VIP-Receptor Targeted Liposomes for Effective Imaging of Breast Cancer.  

National Technical Information Service (NTIS)

However, current methods of breast cancer detection cannot provide accurate results. This study was conceived to begin to address this issue by developing and testing a novel method of active targeting of radionuclide (Tc- 99m) encapsulating sterically st...

H. Onyuksel

2006-01-01

392

Growing hepatic cavernous hemangioma demonstrated by Tc-99m red blood cell scintigraphy.  

PubMed

Hepatic cavernous hemangiomas rarely grow. Although a few cases have been reported in the literature, none used Tc-99m red blood cell scintigraphy. The authors describe such a case here. PMID:10885690

Gorenberg, M; Sopov, W; Groshar, D

2000-07-01

393

BCS–BEC and observed sharp vs. BCS exponential rise in Tc  

NASA Astrophysics Data System (ADS)

We show how a recent generalized Bose–Einstein condensation (GBEC) formalism predicts a sharp rise in Tc with charge-carrier density as observed in variably-doped cuprates, in contrast with the exponential rise predicted by BCS theory.

Grether, M.; de Llano, M.; Tolmachev, V. V.

2013-10-01

394

Production and survival of /sup 99/Tc in He-shell recurrent thermal pulses  

SciTech Connect

After a brief introduction to the present state of art of nuclear beta-decay studies in astrophysics, we report our recent work on the long-standing /sup 99/Tc problem. Having combined a detailed study of the recurrent He-shell thermal-pulse, third dredge-up episodes in a 2.25 M/sub solar/ star and an s-process network calculation, we show that a substantial amount of /sup 99/Tc can be produced by the s-process and can survive to be dredged up to the stellar surface. We stress that the factual observation of /sup 99/Tc at the surface of certain stars does not necessarily preclude the /sup 22/Ne(..cap alpha..,n)/sup 25/Mg reaction from remaining as the neutron source for the s-process. The calculated surface abundances of /sup 99/Tc and elements with neighboring atomic numbers are compared with observations. 43 refs., 5 figs.

Takahashi, K.; Mathews, G.J.; Ward, R.A.; Becker, S.A.

1985-05-30

395

Production and survival of Tc-99 in He-shell recurrent thermal pulses  

NASA Astrophysics Data System (ADS)

After a brief introduction to the present state of art of nuclear beta-decay studies in astrophysics, recent work on the long-standing Tc-99 problem is reported. After combining a detailed study of the recurrent He-shell thermal-pulse, third dredge-up episodes in a 2.25 solar mass star and an s-process network calculation, it is shown that a substantial amount of Tc-99 can be produced by the s-process and can survive to be dredged up to the stellar surface. The factual observation of Tc-99 at the surface of certain stars does not necessarily preclude the Ne-22(alpha, n)Mg-25 reaction from remaining as the neutron source for the s-process. The calculated surface abundances of Tc-99 and elements with neighboring atomic numbers are compared with observations.

Takahashi, K.; Mathews, G. J.; Ward, R. A.; Becker, S. A.

396

Simulation of dielectric resonator for a high-Tc radio frequency superconducting quantum interference device  

NASA Astrophysics Data System (ADS)

Nowadays, the high-critical-temperature radio frequency superconducting quantum interference device (high-Tc rf SQUID) is usually coupled to a dielectric resonator that is a standard 10 × 10 × 1 mm3 SrTiO3 (STO) substrate with a YBa2Cu3O7-? (YBCO) thin-film flux focuser deposited on it. Recently, we have simulated a dielectric resonator for the high-Tc rf SQUID by using the ANSOFT High Frequency Structure Simulator (ANSOFT HFSS). We simulate the resonant frequency and the quality factor of our dielectric resonator when it is unloaded or matches a 50-? impedance. The simulation results are quite close to the practical measurements. Our study shows that ANSOFT HFSS is quite suitable for simulating the dielectric resonator used for the high-Tc rf SQUID. Therefore, we think the ANSOFT HFSS can be very helpful for investigating the characteristics of dielectric resonators for high-Tc rf SQUIDs.

Gao, Ji; Yang, Tao; Ma, Ping; Dai, Yuan-Dong

2010-06-01

397

High temperature magnetic ordering in the 4d perovskite SrTcO3.  

PubMed

We present evidence for possibly the highest magnetic ordering temperature in any compound without 3d transition elements. Neutron powder diffraction measurements, at both time-of-flight and constant wavelength sources, were performed on two independently prepared SrTcO3 powders. SrTcO3 adopts a distorted perovskite structure with G-type antiferromagnetic ordering and has a moment of 1.87(4)?B per Tc cation at room temperature with an extraordinarily high Néel point close to 750 °C. Electronic structure calculations reveal extensive mixing between the technetium 4d states and oxygen states proximal to the Fermi level. This hybridization leads to a close relationship between magnetic ordering temperature and moment formation in SrTcO3. PMID:21405490

Rodriguez, Efrain E; Poineau, Frédéric; Llobet, Anna; Kennedy, Brendan J; Avdeev, Maxim; Thorogood, Gordon J; Carter, Melody L; Seshadri, Ram; Singh, David J; Cheetham, Anthony K

2011-02-07

398

High temperature magnetic ordering in the 4d perovskite SrTcO3  

SciTech Connect

We present evidence for possibly the highest magnetic ordering temperature in any compound without 3d transition elements. Neutron powder diffraction measurements, at both time-of-flight and constant wavelength sources, were performed on two independently prepared SrTcO{sub 3} powders. SrTcO{sub 3} adopts a distorted perovskite structure with G-type antiferromagnetic ordering and has a moment of 1.87(4){mu}{sub B} per Tc cation at room temperature with an extraordinarily high Neel point close to 750 C. Electronic structure calculations reveal extensive mixing between the technetium 4d states and oxygen states proximal to the Fermi level. This hybridization leads to a close relationship between magnetic ordering temperature and moment formation in SrTcO{sub 3}.

Rodriguez, Efrain E. [National Institute of Standards and Technology (NIST), Gaithersburg, MD; Poineau, Frederic [University of Nevada, Las Vegas; Llobet, Anna [Los Alamos National Laboratory (LANL); Kennedy, Brendan J. [University of Technology Sydney; Avdeev, Maxim [Bragg Institute, ANSTO; Thorogood, Gordon J. [Bragg Institute, ANSTO; Carter, Melody L. [ANSTO; Seshadri, Ram [University of California, Santa Barbara; Singh, David J [ORNL; Cheetham, Anthony K. [University of Cambridge

2011-01-01

399

Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)  

SciTech Connect

99Technetium (99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life (t1/2 = 2.13 x 105 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron [Fe(II)], either in aqueous form or in mineral form, has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) have not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total Fe content of these clay minerals, after Fe-oxide removal, ranged from 0.7 to 30.4% by weight, and the Fe(III)/Fe(total) ratio ranged from 44.9 to 98.5%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella Putrifaciens CN32 cells as mediators. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. The extent of Fe(III) bioreduction was the highest for chlorite (~43 wt%) and the lowest for palygorskite (~4.17 wt%). In the S-I series, NAu-2 was the most reducible (~31 %) and illite the least (~0.4 %). The extent and initial rate of bioreduction were positively correlated with the percent smectite in the S-I series (i.e., layer expandability). Fe(II) in the bioreduced clay minerals subsequently was used to reduce Tc(VII) to Tc(IV) in PIPES buffer. Similar to the trend of bioreduction, in the S-I series, reduced smectite showed the highest reactivity toward Tc(VII), and reduced illite exhibited the least. The initial rate of Tc(VII) reduction, after normalization to clay and Fe(II) concentrations, was positively correlated with the percent smectite in the S-I series. Fe(II) in chlorite and palygorskite was also reactive toward Tc(VII) reduction. These data demonstrate that crystal chemical parameters (layer expandability, Fe and Fe(II) contents, and surface area etc.) play important roles in controlling the extent and rate of bioreduction and the reactivity toward Tc(VII) reduction. Reduced Tc(IV) resides within clay mineral matrix, and this association could minimize any potential of reoxidation over long term.

Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

2011-07-01

400

Preclinical evaluation of novel organometallic 99m Tc-folate and 99m Tc-pteroate radiotracers for folate receptor-positive tumour targeting  

Microsoft Academic Search

Purpose  The folate receptor (FR) is a valuable tumour marker, since it is frequently overexpressed on various cancer types. The purpose\\u000a of the present study was to pre-clinically evaluate novel site-specifically modified 99mTc(CO)3 folate (?-derivative 4, ?-derivative 5) and pteroate (6) conjugates for FR targeting.\\u000a \\u000a \\u000a \\u000a Methods  The 99mTc(CO)3 radiotracers 4–6 were prepared by a kit-like procedure. In vitro characterisation (K\\u000a D and

Cristina Müller; Alexander Hohn; P. August Schubiger; Roger Schibli

2006-01-01

401

Generation of a panel of antibodies against proteins encoded on human chromosome 21  

PubMed Central

Background Down syndrome (DS) is caused by trisomy of all or part of chromosome 21. To further understanding of DS we are working with a mouse model, the Tc1 mouse, which carries most of human chromosome 21 in addition to the normal mouse chromosome complement. This mouse is a model for human DS and recapitulates many of the features of the human syndrome such as specific heart defects, and cerebellar neuronal loss. The Tc1 mouse is mosaic for the human chromosome such that not all cells in the model carry it. Thus to help our investigations we aimed to develop a method to identify cells that carry human chromosome 21 in the Tc1 mouse. To this end, we have generated a panel of antibodies raised against proteins encoded by genes on human chromosome 21 that are known to be expressed in the adult brain of Tc1 mice Results We attempted to generate human specific antibodies against proteins encoded by human chromosome 21. We selected proteins that are expressed in the adult brain of Tc1 mice and contain regions of moderate/low homology with the mouse ortholog. We produced antibodies to seven human chromosome 21 encoded proteins. Of these, we successfully generated three antibodies that preferentially recognise human compared with mouse SOD1 and RRP1 proteins on western blots. However, these antibodies did not specifically label cells which carry a freely segregating copy of Hsa21 in the brains of our Tc1 mouse model of DS. Conclusions Although we have successfully isolated new antibodies to SOD1 and RRP1 for use on western blots, in our hands these antibodies have not been successfully used for immunohistochemistry studies. These antibodies are freely available to other researchers. Our data high-light the technical difficulty of producing species-specific antibodies for both western blotting and immunohistochemistry.

2010-01-01

402

The activation of TC10, a Rho small GTPase, contributes to v-Rel-mediated transformation  

Microsoft Academic Search

v-Rel is the oncogenic member of the Rel\\/NF-?B family of transcription factors and transforms hematopoietic cells and fibroblasts. Differential display was employed to identify target genes that exhibit altered expression in v-Rel transformed cells. One of the cDNAs identified encodes the chicken ortholog of TC10, a member of the Rho small GTPase family. The expression of TC10 was increased in

S Tong; A S Liss; M You; H R Bose

2007-01-01

403

Comparison of \\/sup 99m\\/Tc phosphate and diphosphonate complexes in experimental renal infarcts  

Microsoft Academic Search

The 3-hour biodistribution of \\/sup 99m\\/Tc complexes of five diphosphonates (HMDP, NMMDP, DMAD, DPD, and APD), imidodiphosphonate (IDP), and pyrophosphate (PYP) was compared in rats with segmental renal infarction induced by a 1-hour occlusion of a renal artery branch. \\/sup 95m\\/Tc labeled MDP was a reference substance in all animals. Three agents (APD, HMDP and IDP) had a higher infarct\\/normal

J. G. McAfee; D. J. Krauss; G. Subramanian; F. D. Thomas; M. Roskopf; C. Ritter; B. Lyons; J. E. Schoonmaker; R. D. Finn

2009-01-01

404

Role of 99mTc-(V)DMSA in Detecting Tumor Cell Proliferation  

PubMed Central

Pentavalent technetium-99m dimercaptosuccinic acid (99mTc-(V)DMSA) is a tumor-seeking agent which was introduced to evaluate, image, and manage many types of cancers. In this review, the beginning of, and the most recent applications of using this agent was appraised. The relation with tumor cell detection and proliferation was reported and several mechanisms of uptake of 99mTc-(V)DMSA in tumor cells are described.

Al-Saeedi, Fatma

2007-01-01

405

Comparative Analysis of the Recently Discovered hAT Transposon TcBuster in Human Cells  

PubMed Central

Background Transposons are useful tools for creating transgenic organisms, insertional mutagenesis, and genome engineering. TcBuster, a novel hAT-family transposon system derived from the red flour beetle Tribolium castaneum, was shown to be highly active in previous studies in insect embryoes. Methodology/Principal Findings We tested TcBuster for its activity in human embryonic kidney 293 (HEK-293) cells. Excision footprints obtained from HEK-293 cells contained small insertions and deletions consistent with a hAT-type repair mechanism of hairpin formation and non-homologous end-joining. Genome-wide analysis of 23,417 piggyBac, 30,303 Sleeping Beauty, and 27,985 TcBuster integrations in HEK-293 cells revealed a uniquely different integration pattern when compared to other transposon systems with regards to genomic elements. TcBuster experimental conditions were optimized to assay TcBuster activity in HEK-293 cells by colony assay selection for a neomycin-containing transposon. Increasing transposon plasmid increased the number of colonies, whereas gene transfer activity dependent on codon-optimized transposase plasmid peaked at 100 ng with decreased colonies at the highest doses of transposase DNA. Expression of the related human proteins Buster1, Buster3, and SCAND3 in HEK-293 cells did not result in genomic integration of the TcBuster transposon. TcBuster, Tol2, and piggyBac were compared directly at different ratios of transposon to transposase and found to be approximately comparable while having their own ratio preferences. Conclusions/Significance TcBuster was found to be highly active in mammalian HEK-293 cells and represents a promising tool for mammalian genome engineering.

Woodard, Lauren E.; Li, Xianghong; Malani, Nirav; Kaja, Aparna; Hice, Robert H.; Atkinson, Peter W.; Bushman, Frederic D.; Craig, Nancy L.; Wilson, Matthew H.

2012-01-01

406

Magnetic nanoparticle relaxation measured by a low-Tc SQUID system  

Microsoft Academic Search

A low-Tc SQUID system was developed for measuring magnetic relaxation of polymer-coated magnetic nanoparticles (MNPs) in a liquid carrier (e.g. water). The system consists of two low-Tc SQUIDs which are electronically combined to form an axial gradiometer using high-bandwidth directly coupled FLL electronics. The system is operated in a magnetically shielded room. The magnetic relaxation of the investigated MNPs in

A. Haller; S. Hartwig; H. Matz; J. Lange; T. Rheinländer; R. Kötitz; W. Weitschies; L. Trahms

1999-01-01

407

Tc 1Like Transposable Elements in the Genome of Lake Trout ( Salvelinus namaycush )  

Microsoft Academic Search

.   This study reports on the DNA sequence of a Tc1-like transposable element Tsn1 from lake trout (Salvelinus namaycush). Tc1-like elements were amplified by PCR using an oligonucleotide primer based on the Tdr1 element of zebrafish. One full-length and two partial-length copies of the transposon were sequenced. In addition, partial\\u000a Tsn1 elements were recovered from PCR reactions run with primers

Kent M. Reed

1999-01-01

408

Low noise high-Tc superconducting bolometers on silicon nitride membranes for far-infrared detection  

Microsoft Academic Search

High-TcGdBa2Cu3O7?? superconductor bolometers with operation temperatures near 89 K, large receiving areas of 0.95 mm2 and very high detectivity have been made. The bolometers are supported by 0.62 ?m thick silicon nitride membranes. A specially developed silicon-on-nitride layer was used to enable the epitaxial growth of the high-Tc superconductor. Using a gold black absorption layer an absorption efficiency for wavelengths

M. P. Bruijn; R. de Vries; J. J. Wijnbergen; P. A. J. de Korte; S. Sįnchez; M. Elwenspoek; T. Heidenblut; B. Schwierzi; W. Michalke; E. Steinbeiss

1997-01-01

409

Minimally Invasive Radio-guided Surgery for Hyperparathyroidism: An Experience with Tc99m Sestamibi  

Microsoft Academic Search

Introduction: Radio-guided parathyroid surgery along with other minimally invasive surgeries constitutes the main surgical treatment procedures for different kinds of hyperparathyroidism. In this article we have reported our experience of radio-guided parathyroid surgery using Tc-99m sestamibi. Methods: Ten patients with hyperparathyroidism included in our study. Twenty mCi of Tc-99m sestamibi was injected intravenously to the patients in the day of

Mohammad Naser Forghani; Mostafa Mehrabibahar; Vahid Reza; Dabbagh Kakhki; Seyed Rasoul Zakavi; Kamran Aryana; Abbas Abdollahi; Ramin Sadeghi

410

Detection of gastritis by /sup 99m/Tc-labeled red-blood-cell scintigraphy  

SciTech Connect

Gastritis is a common condition, with a variety of causes, that is diagnosed most often by barium upper gastrointestinal tract series or endoscopy. The authors report a case in which gastritis without active bleeding was apparent in scintiscans obtained during the evaluation of GI bleeding using /sup 99m/Tc-labeled red blood cells (TcRBC). The scintigraphic findings that suggest gastritis are described.

Wilton, G.P.; Wahl, R.L.; Juni, J.E.; Froelich, J.W.

1984-10-01

411

Heterogeneous reduction of Tc(VII) by Fe(II) at the solid–water interface  

Microsoft Academic Search

Experiments were performed herein to investigate the rates and products of heterogeneous reduction of Tc(VII) by Fe(II) adsorbed to hematite and goethite, and by Fe(II) associated with a dithionite–citrate–bicarbonate (DCB) reduced natural phyllosilicate mixture [structural, ion-exchangeable, and edge-complexed Fe(II)] containing vermiculite, illite, and muscovite. The heterogeneous reduction of Tc(VII) by Fe(II) adsorbed to the Fe(III) oxides increased with increasing pH

Tetyana Peretyazhko; John M. Zachara; Steve M. Heald; Byong Hun Jeon; Ravi K. Kukkadapu; Chongxuan Liu; Dean A. Moore; Charles T. Resch

2008-01-01

412

Synthesis and evaluation of 99mTc-moxifloxacin, a potential infection specific imaging agent  

Microsoft Academic Search

To synthesize and evaluate a 99mTc labeled fluroquinolone, moxifloxacin as a potential bacteria specific infection imaging agent. A radiolabeling formulation including moxifloxacin, [MoxicipTM injection, Cipla] (4mg), sodium pertechnetate and stannous chloride (5?g) gave the best radiolabeling efficiency and moderately stable labeled 99mTc moxifloxacin. Quality control analysis was performed by ITLC. Rats and rabbit with infectious intramuscular lesions induced in either

Sankha Chattopadhyay; Sujata Saha Das; Susmita Chandra; Kakali De; Mridula Mishra; Bharat Ranjan Sarkar; Samarendu Sinha; Shantanu Ganguly

2010-01-01

413

Regional brain uptake and retention of Tc-99m-propylene amine oxime derivatives  

SciTech Connect

Tc-99m-propylene amine oxime (Tc-99m-PnAO) is a neutral lipophilic chelate that rapidly and passively enters the cerebral cortex (80% on first pass in baboon brain) and then clears exponentially leaving inadequate activity to perform conventional SPECT brain imaging. When side chains are attached to the PnAO backbone lipophilicity is increased, as well as brain retention. In this work the authors evaluated regional brain uptake and retention of Tc-99m-PnAO and several of its derivatives in rat brain using serial autoradiography (ARG). Autoradiographs of each Tc-99m chelate at 5 sec. post peak brain uptake demonstrate discrete grey to white matter differentiation. White matter tracts are well delineated and the darker areas of grey matter appearing in the midbrain and thalamus, corresponding to areas of high capillary density and high blood flow documented with C-14-iodoantipyrine, are easily distinguished. Within 5 min. of the peak uptake the regional uptake and grey/white differentiation is lost on the Tc-99m-PnAO ARG. In contrast the 5 min. ARG of the more lipophilic Tc-99m, chelate with dimethyl-PnAO (DMPnAO) shows the complete reverse of the 5 sec. ARG, with greater activity in the white matter tracts than in the grey matter. One of the derivatives, tetramethyl-PAO (TMPAO) complexed with Tc-99m is retained in the grey matter of rat brain and shows persistent grey to white localization for at least 60 min., analogous to what has been reported with I-123-IMP. These results suggest that Tc-99m-TMPAO or one of its derivatives may be appropriate for SPECT imaging of cerebral blood flow abnormalities.

Chaplin, S.B.; Oberle, P.O.; Hoffman, T.J.; Volkert, W.A.; Holmes, R.A.; Nowotnik, D.P.; Pickett, R.D.; Neirinckx, R.

1985-05-01

414

Spectroscopic evidence for a pseudogap in the normal state of underdoped high-Tc superconductors  

Microsoft Academic Search

IT is well known that BCS mean-field theory is remarkably successful in describing conventional superconductors. A central concept of BCS theory is the energy gap in the electronic excitation spectrum below the superconducting transition temperature, Tc. The gap also serves as the order parameter: quite generally, long-range phase coherence and a non-zero gap go hand-in-hand1. But in underdoped high-Tc superconductors

H. Ding; T. Yokoya; J. C. Campuzano; T. Takahashi; M. Randeria; M. R. Norman; T. Mochiku; K. Kadowaki; J. Giapintzakis

1996-01-01

415

Acute effects of nicotinic acid on hepatic transport of 99m Tc-PIPIDA  

Microsoft Academic Search

Hepatic injury has been associated with nicotinic acid treatment of schizophrenia and hypercholesterolemia. This association was implicated when the liver and biliary tract were not visualized after 99mTc-HIDA in a patient taking 3 g daily of nicotinic acid. We studied hepatic transport of 99mTc-PIPIDA both in vitro in isolated hepatocytes and in vivo in rabbits pretreated with nicotinic acid to

Rex B. Shafer; Robert G. Knodell; Laura N. Stanley; Michael K. Elson

1983-01-01

416

Production and survival of Tc99 in He-shell recurrent thermal pulses  

Microsoft Academic Search

After a brief introduction to the present state of art of nuclear beta-decay studies in astrophysics, recent work on the long-standing Tc-99 problem is reported. After combining a detailed study of the recurrent He-shell thermal-pulse, third dredge-up episodes in a 2.25 solar mass star and an s-process network calculation, it is shown that a substantial amount of Tc-99 can be

K. Takahashi; G. J. Mathews; R. A. Ward; S. A. Becker

1986-01-01

417

Tc99m DMSA renal uptake: influence of biochemical and physiologic factors  

Microsoft Academic Search

Thirty-eight female Sprague-Dawley rats were studied to determine the effects of (a) tubular blockade and (b) commonly encountered changes in hydration and acid-base balance, on the urinary excretion and renal localization of Tc-99m dimercaptosuccinic acid (DMSA). Ten additional rats were studied to quantitate the in vivo protein binding of Tc-99m DMSA, and a final group of 12 animals was used

C. A. Yee; H. B. Lee; M. D. Blaufox

1981-01-01

418

99mTc DMSA renal uptake: influence of biochemical and physiologic factors  

Microsoft Academic Search

Thirty-eight female Sprague-Dawley rats were studied to determine the effects of (a) tubular blockade and (b) commonly encountered changes in hydration and acid-base balance, on the urinary excretion and renal localization of 99mTc dimercaptosuccinic acid (DMSA). Ten additional rats were studied to quantitate the in vivo protein binding of 99mTc DMSA, and a final group of 12 animals was used

C. A. Yee; H. B. Lee; M. D. Blaufox

1981-01-01

419

High tc superconductor radiation detector. Phase 1 final report. Report for 1 January30 September 1989  

Microsoft Academic Search

The goal of the project was to demonstrate the feasibility of building high Tc superconductor radiation detectors for use as high energy resolution spectrometers. Low Tc superconductor tunneling junctions were fabricated in an S-I-S configuration out of Sn and SnO2 and were capable of detecting alpha particles. This confirmed the concept of using tunneling junctions as radiation detectors. The primary

G. Entine; M. Soller

1989-01-01

420

Quality audit programme for 99mTc and 131I radioactivity measurements with radionuclide calibrators  

Microsoft Academic Search

The use of radiopharmaceuticals in nuclear medicine for diagnosis and therapy has increased over the years with 99mTc and 131I being most widely used. Quality audit programmes for radioactivity measurements of 131I have been ongoing and the 12th audit was recently conducted among seventy nuclear medicine centres (NMC) in India. An audit for the activity measurements of 99mTc was conducted

Leena Joseph; R. Anuradha; D. B. Kulkarni

2008-01-01

421

Zero-Bias Conductance Peak in Normal-Metal / HIGH-TC Superconductor Junctions  

NASA Astrophysics Data System (ADS)

We report the effects of an interfacial roughness on the zero-bias conductance peak (ZBCP) in normal-metal / high Tc superconductor junctions. The roughness at a surface of superconductors strongly suppresses the ZBCP when the transparency of the interface is sufficiently low. In a numerical simulation at a zero-magnetic field, we confirm the split of the ZBCP owing to the interfacial roughness in realistic band structures of the high-Tc superconductors.

Asano, Y.; Tanaka, Y.

2003-03-01

422

Scintigraphic detection of osteomyelitis with Tc-99m MDP and Ga-67 citrate: concise communication. [Rabbits  

SciTech Connect

Using both Tc-99m methylene diphosphonate and gallium-67 citrate, images of the lower extremities in New Zealand white rabbits were obtained on sequential days after inoculation of tibias with Staphylococcus aureus. Gallium-67 scintigraphy was positive earlier in the course of infection than Tc-99m MDP scintigraphy. In addition to 4-hr Ga-67 scintigrams, 24-hr and 48-hr scintigrams were obtained contributing substanitally to interpretation. However, 72-hr Ga-67 scintigrams contributed little additional information.

Graham, G.D.; Lundy, M.M.; Frederick, R.J.; Hartshorne, M.F.; Berger, D.E.

1983-11-01

423

Shape Evolution and Triaxiality in Neutron Rich Y, Nb, Tc, rh and Ag  

NASA Astrophysics Data System (ADS)

New level schemes to high spin are extracted for 99,101Y, 101,105Nb, 105,107,109Tc, 111,113Rh and 115,117Ag from prompt ?-?-? coincidences studies of 252Cf with Gammasphere. The ?5/2+[422] bands in 99,101Y and 101,105Nb and 7/2+[413] bands in 105,107,109Tc, 111,113Rh and 115,117Ag exhibit a smooth evolution from strong prolate deformation with very little signature splittings in 99,101Y to triaxial deformation with large and near maximum splitting in the Tc, Rb and Ag nuclei. These splitting data along with the presence of an excited 11/2+ bands with almost no decay to the 7/2+ levels in the Tc and Rh nuclei indicate the increasing importance of rigid triaxial shapes in these nuclei. The Nb isotopes having intermediate splitting between Y and Tc, Rh isotopes may suggest that they are transitional nuclei with regard to triaxial deformation. Triaxial-rotor-plus-particle model calculations yielded best fits to the energies, signature splitting and transition probabilities for ?(? ?2)?0.32 and ? = -22.5° for 107Tc and ?2 = 0.28 and near maximum triaxiality, ? = -28°, for 111,113Rh. A K=1/2 band based on the 1/2+[431] intruder orbital with large deformation is seen in 105,107Tc and 111,113Rh with anomalous spaces where the 1/2, 5/2, ... are above the 3/2, 7/2, ... levels. Band crossings are seen in 105,107,109Tc and 111,113Rh with spin alignments that indicate the alignment of a h11/2 neutron pair.

Luo, Y. X.; Rasmussen, J. O.; Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Zhu, S. J.; Gore, P. M.; Jones, E. F.; Wu, S. C.; Gilat, J.; Lee, I. Y.; Fallon, P.; Ginter, T. N.; Ter-Akopian, G.; Daniel, A. V.; Stoyer, M. A.; Donangelo, R.; Gelberg, A.

2005-03-01

424

New level schemes with high-spin states of 105,107,109 Tc  

NASA Astrophysics Data System (ADS)

New level schemes of odd- Z 105,107,109 Tc are proposed based on the 252 Cf spontaneous-fission-gamma data taken with Gammasphere in 2000. Bands of levels are considerably extended and expanded to show rich spectroscopic information. Spin/parity and configuration assignments are made based on determinations of multipolarities of low-lying transitions and the level analogies to the previously reported levels, and to those of the neighboring Rh isotopes. A non-yrast negative-parity band built on the 3/ 2- [ 301 ] orbital is observed for the first time in 105 Tc . A positive-parity band built on the 1/ 2+ [ 431 ] intruder orbital originating from the ? ( g7/2 / d5/2 ) subshells and having a strong deformation-driving effect is observed for the first time in 105 Tc , and assigned in 107 Tc . A positive-parity band built on the excited 11/ 2+ level, which has rather low excitation energy and predominantly decays into the 9/ 2+ level of the ground state band, provides evidence of triaxiality in 107,109 Tc , and probably also in 105 Tc . Rotational constants are calculated and discussed for the K=1/2 intruder bands using the Bohr-Mottelson formula. Level systematics are discussed in terms of the locations of proton Fermi levels and deformations. The band crossings of yrast positive-parity bands are observed, most likely related to h11/2 neutron alignment. Triaxial-rotor-plus-particle model calculations performed with ?=0.32 and ?=-22.5° on the prolate side of maximum triaxiality yielded the best reproduction of the excitation energies, signature splittings, and branching ratios of the positive-parity bands (except for the intruder bands) of these Tc isotopes. The significant discrepancies between the triaxial-rotor-plus-particle model calculations and experiment for the K=1/2 intruder bands in 105,107 Tc need further theoretical studies.

Luo, Y. X.; Rasmussen, J. O.; Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Zhu, S. J.; Gore, P. M.; Wu, S. C.; Lee, I. Y.; Fallon, P.; Ginter, T. N.; Ter-Akopian, G. M.; Daniel, A. V.; Stoyer, M. A.; Donangelo, R.; Gelberg, A.

2004-10-01

425

Physical phantom evaluation of simultaneous 99mTc\\/ 123I SPECT imaging  

Microsoft Academic Search

Simultaneous dual-isotope imaging from two different energy gamma rays such as 99mTc and 123I is a promising technology in nuclear medicine. Its advantages are to abbreviate the acquisition procedure with an identical geometrical registration of the different isotope images, the same physiological condition without motion artifacts, and help patient throughput and comfort. However, the energy photopeaks of 99mTc and 123I

Bang-Hung Yang; Shyh-Jen Wang; Jhih-Shian Lee; Meei-Ling Jan; Chia-Jung Chang; Jyh-Cheng Chen

2011-01-01

426

99m Tc-exorphin C: A new peptide radiopharmaceutical for tumor imaging  

Microsoft Academic Search

Summary  The aim of this study was to label exorphin C with 99mTc and to examine its usefulness as opioid receptor binding radiopharmaceutical in Albino Wistar rats. Exorphin C, which is a peptide with 5 aminoacids, was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Labeling efficiency was higher than 98%. The compound was stable for at least

T. Ertay; P. Unak; C. Tasci; F. Z. Biber; F. Zihnioglu; H. Durak

2005-01-01

427

Preparation, quality control and stability of 99m Tc-cefuroxime axetil  

Microsoft Academic Search

Cefuroxime axetil, a cephalosporin antibiotic used to treat bacterial infections, was investigated to label with 99mTc. Radiolabeling of cefuroxime axetil was carried out by using stannous chloride method. Effects of pH and stannous chloride\\u000a amount on the radiolabeling yield were investigated. The radiochemical purity of 99mTc-cefuroxime axetil was determined by thin layer radio chromatography (TLRC), electrophoresis and high performance liquid

F. Yurt Lambrecht; K. Durkan; P. Unak

2008-01-01

428

Planning, implementation, and first results of the Tropical Composition, Cloud and Climate Coupling Experiment (TC4)  

Microsoft Academic Search

The Tropical Composition, Cloud and Climate Coupling Experiment (TC4), was based in Costa Rica and Panama during July and August 2007. The NASA ER-2, DC-8, and WB-57F aircraft flew 26 science flights during TC4. The ER-2 employed 11 instruments as a remote sampling platform and satellite surrogate. The WB-57F used 25 instruments for in situ chemical and microphysical sampling in

Owen B. Toon; David O. Starr; Eric J. Jensen; Paul A. Newman; Steven Platnick; Mark R. Schoeberl; Paul O. Wennberg; Steven C. Wofsy; Michael J. Kurylo; Hal Maring; Kenneth W. Jucks; Michael S. Craig; Marilyn F. Vasques; Lenny Pfister; Karen H. Rosenlof; Henry B. Selkirk; Peter R. Colarco; Stephan R. Kawa; Gerald G. Mace; Patrick Minnis; Kenneth E. Pickering

2010-01-01

429

Evaluation of the Allergenicity Potential of TcPR-10 Protein from Theobroma cacao  

Microsoft Academic Search

BackgroundThe pathogenesis related protein PR10 (TcPR-10), obtained from the Theobroma cacao-Moniliophthora perniciosa interaction library, presents antifungal activity against M. perniciosa and acts in vitro as a ribonuclease. However, despite its biotechnological potential, the TcPR-10 has the P-loop motif similar to those of some allergenic proteins such as Bet v 1 (Betula verrucosa) and Pru av 1 (Prunus avium). The insertion

Sara Pereira Menezes; Jane Lima dos Santos; Thyago Hermylly Santana Cardoso; Carlos Priminho Pirovani; Fabienne Micheli; Fįtima Soares Motta Noronha; Andréa Catćo Alves; Ana Maria Caetano Faria; Abelmon da Silva Gesteira

2012-01-01

430

The absorption of (99m)Tc-alendronate given by rectal route in rabbits.  

PubMed

Alendronate sodium (ALD) is a bisphosphonate medication used in the treatment and prevention of osteoporosis. Absorption of ALD as oral formulation is very poor (0.5%-1%). Its bioavailability can decrease with food effect. It has some gastrointestinal adverse effects such as gastritis, gastric ulcer, and esophagitis. The aim of this study was to develop a rectal formulation of ALD as an alternative to oral route and to investigate the absorption of it by using gamma scintigraphy. For this reason, ALD was labeled with Technetium-99m ((99m)Tc) by direct method. The radiochemical characterization of the (99m)Tc-ALD was carried out by paper chromatography, thin layer chromatography, and electrophoresis methods. The labeling efficiency of (99m)Tc-ALD was found 99% without significant changes until 6 h postlabeling at room temperature. The rectal suppositories containing (99m)Tc-ALD were prepared by fusion method using polyethylene glycol (PEG) 1500. The (99m)Tc-labeled ALD suppositories were administrated to rabbits by rectal route. Serial scintigrams over all bodies of the rabbits were obtained at different time intervals using a gamma camera. We found that the rectal absorption of (99m)Tc-ALD from suppository formulation was possible. According to our results, this formulation of ALD can be suggested for the therapy of osteoporosis as an alternative route. PMID:18484490

Asiko?lu, Makbule; Ozguney, Isik; Ozcan, Ipek; Orumlu, Oya; Guneri, Tamer; Koseo?lu, Kamil; Ozkilic, Hayal

2008-01-01

431

Comparison in rabbits of chole-scintigraphic properties of several 99mTc-IDA derivatives.  

PubMed

Pathways and kinetics of excretion were compared to four 99mTc-IDA derivatives in healthy rabbits of both sexes. Assessment of differences between the compounds was based upon: plasma clearance, characteristics of time-activity curves measured scintigraphically over the liver (time of the peak Tmax; time for decline of activity to half the peak value-T50%), and hepatocytic mean transit time (MTT) as derived after deconvolution of the hepatic time-activity curve. Hepatocyte transit time was short and similar to 99mTc-complexes of Mebrofenin, 2,4-diethyl IDA (HEPIDA) and 3-iodo-2,6-diethylphenylcarbamoylmethyliminodiacetic acid (JODIDA); it was evidently longer for 99mTc-p-butyl-IDA (BIDA). 99mTc-HEPIDA displayed significant urinary elimination; the remaining three compounds were excreted practically completely via the biliary route. It is concluded that optimal parameters were displayed by 99mTc-Mebrofenin and 99mTc-JODIDA. PMID:3797258

Kapu?ci?ski, J; Liniecki, J; Durski, K; Mikiciuk-Olasik, E

1986-10-01

432

Click chemistry for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin.  

PubMed

(99m)Tc-HYNIC labeled Lys(3)-bombesin has shown specific binding to gastrin-releasing peptide receptors (GRP-r) over-expressed in cancer cells. Click chemistry offers an innovative functionalization strategy for biomolecules such as bombesin. The aim of this research was to apply a click chemistry approach for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin and to compare the in vitro MCF7 breast cancer cell uptake and biodistribution profile in mice with that of (99m)Tc-EDDA/HYNIC-Lys(3)-bombesin. The results suggest a higher lipophilicity for (99m)Tc(CO)(3)-triazole-Lys(3)-bombesin which explains its higher in vivo hepatobiliary elimination. Pancreas-to-blood ratio for (99m)Tc(CO)(3)-triazole-Lys(3)-bombesin was 4.46 at 3 h and both bombesin radiopharmaceuticals showed specific recognition for GRP receptors in MCF7 cancer cells. Click chemistry is a reliable approach for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin. PMID:20580238

Ferro-Flores, G; Rivero, I A; Santos-Cuevas, C L; Sarmiento, J I; Arteaga de Murphy, C; Ocampo-Garcķa, B E; Garcķa-Becerra, R; Ordaz-Rosado, D

2010-06-17

433

Investigation of Tc Migration Mechanism During Bulk Vitrification Process Using Re Surrogate  

SciTech Connect

As a part of Bulk vitrification (BV) performance enhancement tasks, Laboratory scoping tests were performed in FY 2004-2005 to explore possible ways to reduce the amount of soluble Tc in the BV waste package. Theses scoping tests helped identify which mechanisms play an important role in the migration of Tc in the BV process (Hrma et al. 2005 and Kim et al. 2005). Based on the results from these scoping tests, additional tests were identified that will improve the understanding of Tc migration and to clearly identify the dominant mechanisms. The additional activities identified from previous studies were evaluated and prioritized for planning for Tasks 29 and 30 conducted in FY2006. Task 29 focused on the improved understanding of Tc migration mechanisms, and Task 30 focused on identifying the potential process changes that might reduce Tc/Re migration into the castable refractory block (CRB). This report summarizes the results from the laboratory- and crucible-scale tests in the lab for improved Tc migration mechanism understanding utilizing Re as a surrogate performed in Task 29.

Kim, Dong-Sang; Bagaasen, Larry M.; Crum, Jarrod V.; Fluegel, Alex; Gallegos, Autumn B.; Martinez, Baudelio; Matyas, Josef; Meyer, Perry A.; Paulsen, Dan; Riley, Brian J.; Schweiger, Michael J.; Stewart, Charles W.; Swoboda, Robert G.; Yeager, John D.

2006-12-04

434

Almahata Sitta (=asteroid 2008 TC3) and the search for the ureilite parent body  

NASA Astrophysics Data System (ADS)

This article explores what the recovery of 2008 TC3 in the form of the Almahata Sitta meteorites may tell us about the source region of ureilites in the main asteroid belt. An investigation is made into what is known about asteroids with roughly the same spectroscopic signature as 2008 TC3. A population of low-inclination near-Earth asteroids is identified with spectra similar to 2008 TC3. Five asteroid families in the Main Belt, as well as a population of ungrouped asteroids scattered in the inner and central belts, are identified as possible source regions for this near-Earth population and 2008 TC3. Three of the families are ruled out on dynamical and spectroscopic grounds. New near-infrared spectra of 142 Polana and 1726 Hoffmeister, lead objects in the two other families, also show a poor match to Almahata Sitta. Thus, there are no Main Belt spectral analogs to Almahata Sitta currently known. Space weathering effects on ureilitic materials have not been investigated, so that it is unclear how the spectrum of the Main Belt progenitor may look different from