Note: This page contains sample records for the topic tc generators sintesis from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

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; Václav Hušák; Jaroslav Rohá?ek

1979-01-01

2

Study to Modify the Elution System in a Sup(99M)Tc Generator.  

National Technical Information Service (NTIS)

The sup(99m)Tc generator is a system that allows us to obtain sup(99m)Tc through the radioactive desintegration of exp 99 Mo, a radionuclide absorbed in an alumina chromatographic column, the sup(99m)Tc extraction is accomplished by elution and the exp 99...

B. Delgado S

1979-01-01

3

Results of regular study on radionuclidic purity of 99mTc obtained from 99Mo--99mTc generators.  

PubMed

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 2.9 X 10(-3) to 2.8 X 10(-1) per cent of 99mTc activity. The additional total body absorbed dose caused by these contaminants, as calculated from their average content in 99mTc eluates, was less than 1% of the dose due to 99mTc pertechnetate. PMID:520349

Vlcek, J; Husák, V; Rohácek, J

1979-10-01

4

Ruthenium Radioisotopes as Contaminants in Eluates from Mo-Tc Generators  

Microsoft Academic Search

The measurement of the Ru content in Tc eluates from Mo-Tc generators is difficult because of the proximity of the Ru and Ru gamma-ray spectral peaks and the low Ru content. Ru causes a relatively high whole-body dose, similarly as known contaminants Co, Cs, Ba and some others. Assuming that ruthenium is eliminated from the body with the biological half-life

J. Vl?ek; V. Hušák; J. Rohá?ek; V. Rusek

1978-01-01

5

Development of a 99Mo/99mTc generator using alumina microspheres for industrial radiotracer applications.  

PubMed

A chromatographic (99)Mo/(99m)Tc generator for industrial applications has been developed using alumina microspheres synthesized through sol-gel process to obtain (99m)Tc in both aqueous and non-aqueous media. The sorbent was mesoporous, mechanically strong and possessed high surface area. (99m)Tc could be eluted from generator system using either acetone or 0.9% NaCl solution with appreciably high yields and high radiochemical as well as radionuclidic purity. The facile, versatile generator provides an efficient way to access (99m)Tc at industrial sites for radiotracer applications. PMID:21820904

Dash, Ashutosh; Chakravarty, Rubel; Ram, Ramu; Pillai, K T; Yadav, Yugandhara Y; Wagh, D N; Verma, Rakesh; Biswas, Sujoy; Venkatesh, Meera

2012-01-01

6

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

7

Magnesium-Molybate Compounds as Matrix for 99Mo/99mTc Generators  

PubMed Central

This work reports the preparation of a 99mTc generator based on conversion of 99Mo produced by neutron irradiation, into insoluble magnesium 99Mo-molybdates compounds as matrix. The effect of magnesium salt types and concentration, Mg:Mo molar ratios, pH of molybdate solutions, eluate volume as well as the addition order of molybdate and magnesium solutions' influences on the final 99mTc were evaluated. Polymetalates and polymolybdates salts either crystallized or amorphous were obtained depending on the magnesium salt and Mg:Mo molar ratio used in matrix preparation. 99Mo/99mTc generator production based on magnesium-99Mo molybdate compounds allow reduction of preparation time and eliminates the use of specialized installations. The best generator performances were attained using matrices prepared from 0.1 mol/L MgCl2·6H2O solutions, ammonium molybdate solutions at pH 7 and at a Mg:Mo molar ratio of 1:1.

Monroy-Guzman, Fabiola; Jimenez Martinez, Thania Susana; Arriola, Humberto; Longoria Gandara, Luis Carlos

2011-01-01

8

IL-21 Is Increased in Peripheral Blood of Emphysema Mice and Promotes Th1/Tc1 Cell Generation In Vitro.  

PubMed

Interleukin-21 (IL-21) has been reported to be involved in many Th1-associated diseases. However, the alteration and immune regulation of IL-21 in emphysema remains unknown. In this study, we tested the levels of IFN-? and IL-21 and the frequencies of Th1 and Tc1 in peripheral blood from cigarette smoke (CS)-exposed mice and air-exposed mice and explored the effect of IL-21 on generation of Th1 and Tc1 cells in vitro. It was found that the levels of IFN-? and IL-21 and the frequencies of Th1, Tc1, CD4(+) IL-21(+), CD4(+) IL-21R(+), and CD8(+) IL-21R(+) T cells were much higher in CS-exposed mice. Moreover, the levels of IL-21 were correlated positively with Th1 cells and with Tc1 cells. Finally, the in vitro experiments showed that IL-21 could promote Th1/Tc1 cell generation in CS-exposed mice. These results indirectly provide evidence that IL-21 produced by CD4(+) T cells could promote Th1/Tc1 response, leading to systemic inflammation in emphysema. PMID:24357415

Duan, Minchao; Huang, Ying; Zhong, Xiaoning; Tang, Haijuan

2014-06-01

9

Short electrical pulse generation using light-induced switching in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

This report demonstrates that optically triggered switches based on high Tc superconductor thin films can be used for the generation of sub-nanosecond rise time high-power pulses. Presented in this article are the experimental investigations of the light-induced switching dynamics in YBCO thin films biased by high-current nanosecond duration pulses. This research indicates that a high-power superconducting opto-electronic opening switch can operate in several regimes. The following transitions between the various states of the film are realized: superconducting to normal (S-N), super-conducting to mixed (S-M), low resistance mixed to high resistance mixed (MLR-MHR) and mixed to normal (M-N). When the superconductor is biased with a high current, the value of the light intensity needed for triggering the switch decreases by several times. The explanation of the main light-induced switching characteristics and their behavior is based on a model, which takes into account the simultaneous action of the light and the bias current on the superconducting film. The report also includes a discussion f the ultra-fast film damaging phenomenon which appears as a result of the dissipation of intense power during switching. Discussed is also how this process limits the highest amplitude of the generated pulse. The possible application of high-power superconducting opto-electronic switches for the creation of jitter free radar is also discussed.

Balevicius, Saulius

2001-03-01

10

Application possibilities of a new generator concept for 99m Tc production by means of the Triga-Mark III reactor in Mexico  

Microsoft Academic Search

A new concept of prefabricated99mTc generator has been experimentally tested as a possible procedure for local production of99mTc for medical purposes by means of the ININ-Salazar \\/Mexico\\/ Triga-Mark III reactor working at 1 MW.

K. Svoboda; J. Lezama; J. Tendilla; F. Melichar; M. Tympl

1985-01-01

11

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

12

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

13

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

2013-11-01

14

Lightning-generated NOx seen by the Ozone Monitoring Instrument during NASA's Tropical Composition, Cloud and Climate Coupling Experiment (TC4)  

NASA Astrophysics Data System (ADS)

We present case studies identifying lightning-generated upper tropospheric NOx (LNOx) observed during NASA's Tropical Composition, Cloud and Climate Coupling Experiment (TC4) in July and August 2007. In the campaign, DC-8 aircraft missions, flown from Costa Rica, recorded in situ NO2 profiles near active storms and in relatively quiet areas. We combine these TC4 DC-8 data with satellite data from the Ozone Monitoring Instrument (OMI) to estimate the lightning-generated NO2 (LNO2), above background levels, in the observed OMI NO2 fields. We employ improved off-line processing techniques to customize the OMI retrieval for LNO2. Information on lightning flashes (primarily cloud-to-ground) observed by the Costa Rica Lightning Detection Network operated by the Instituto Costarricense de Electricidad and the World Wide Lightning Location Network were examined over storms upwind of regions where OMI indicates enhanced LNO2. These flash data are compared with Tropical Rainfall Measuring Mission/Lightning Imaging Sensor satellite data to estimate total flashes. Finally, using [NOx]/[NO2] ratios from NASA's Global Modeling Initiative model, we estimate LNOx production per flash for four cases and obtain rates of ˜100-250 mol/flash. These are consistent with rates derived from previous studies of tropical and subtropical storms and below those from modeling of observed midlatitude storms. In our study, environments with stronger anvil-level winds were associated with higher production rates. LIS flash footprint data for one of the low-LNOx production cases with weak upper tropospheric winds suggest below-average flash lengths for this storm. LNOx enhancements over background determined from the OMI data were in less than, but roughly proportional to, aircraft estimates.

Bucsela, Eric J.; Pickering, Kenneth E.; Huntemann, Tabitha L.; Cohen, Ronald C.; Perring, Anne; Gleason, James F.; Blakeslee, Richard J.; Albrecht, Rachel I.; Holzworth, Robert; Cipriani, James P.; Vargas-Navarro, Dylana; Mora-Segura, Ileana; Pacheco-HernáNdez, Alexia; Laporte-Molina, Sadí

2010-05-01

15

I. Investigations of behavior of commercially available /sup 99/Molybdenum//sup 99m/Technetium radionuclide generators. II. Liquid chromatographic characterization and biological distribution studies on a new skeletal imaging agent: /sup 99m/Tc - dimethylaminomethylene diphosphonate  

SciTech Connect

This work describes a comprehensive investigation into the behavior characteristics of commercially available /sup 99/Molybdenum-/sup 99m/Technetium chromatographic radionuclide generators. Generators are tracked throughout their normal clinical lifetimes and the generator eluants are subjected to several analytical procedures for the determination of total technetium (/sup 99/Tc + /sup 99m/Tc) concentrations. Several operational parameters of the generators and several characteristics of their eluants are systematically studied. Generators from four US manufacturers are studied. Four analytical techniques for the determination of medium energy beta particles such as the particle from /sup 99/Tc are used for the redundant analysis of the generator eluants. The data from the various analytical techniques is compared to behavior characteristics predicted by the currently accepted theory governing generator performance. Possible mechanisms explaining the non-theoretical behavior of the generators are examined by statistical correlations of the observed behavior, the analytical results and calculated generator parameters. This work also describes the characterization and separation, by liquid chromatographic techniques, of analogs of borohydride reduced technetium with dimethylaminomethylene diphosphonate.

Holland, M.E.

1984-01-01

16

Telemetry/Telecommand (TM/TC) Processor Study.  

National Technical Information Service (NTIS)

The functions of a telemetry/telecommand (TM/TC) processor for ESA ESGE are established. Functions performed by the TC front end equipment (FEE) include video signal generation, interface with the RF part, telecommand processing interface with the master ...

J. F. Carrasco

1984-01-01

17

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

SciTech Connect

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 {sup 99}Mo 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 since 1970s and (iii) minimize dependency on weekly import of fission-produced {sup 99}Mo raw material required for alumina column generator. Extensive investigations on process standardisation for zirconium molybdate gel (ZMG) led to a steady progress, achieved both in terms of process technology and final performance of {sup 99m}Tc gel generators. The {sup 99m}Tc final product purity from the Indian gel system was comparable to that obtained from the gold-standard alumina column generators. Based on the feasibility established for reliable small-scale production, as well as satisfactory clinical experience with a number of gel generators used in collaborating hospital radiopharmacies, full-fledged mechanised processing facilities for handling up to 150 g of ZMG were set up. The indigenous design and development included setting up of shielded plant facilities with pneumatic-driven as well as manual controls and special gadgets such as, microwave heating of the zirconium molybdate cake, dispenser for gel granules, loading of gel columns into pre-assembled generator housing etc. Formal review of the safety features was carried out by the regulatory body and stage-wise clearance for processing low and medium level {sup 99}Mo activity was granted. Starting from around 70 GBq {sup 99}Mo handling, the processing facilities have since been successfully operated at a level of 740 GBq {sup 99}Mo, twice a month. In all 18 batches of gel have been processed and 156 generators produced. The individual generator capacity was 15 to 30 GBq with an elution yield of nearly 75%. 129 generators were supplied to 11 user hospitals and the estimated number of clinical studies done is well over 5000. The salient aspects of the Indian experience have been reported in many a forum and shared with the IAEA through the on-going CRP. The detailed process know-how is available for technology transfer from BRIT, India. (author)

Saraswathy, P.; Dey, A.C.; Sarkar, S.K.; Kothalkar, C.; Naskar, P.; Arjun, G.; Arora, S.S.; Kohli, A.K. [Board of Radiation and Isotope Technology (BRIT), BARC Vashi Complex, Navi Mumbai 400705 (India); Meera, V.; Venugopal, V. [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre (BARC), Mumbai 400085 (India); Ramamoorthy, N. [Division of Physical and Chemical Sciences, International Atomic Energy Agency (IAEA), A-1400 Vienna (Austria)

2008-07-15

18

Superconducting bolometers: High- Tc and low- Tc  

SciTech Connect

A description is given of recent work at Berkeley on superconducting detectors and mixers for infrared and millimeter wavelengths. The first report is a review article which summarizes the status of development of superconducting components for infrared and millimeter wave receivers. Next, a report is given on measurements and theoretical modeling of the absorptivity (surface resistance) of high quality epitaxial films of the high-{Tc} superconductor YBCO from 750 GHz to 21 THz. The next report describes measurements of the thermal boundary resistance between YBCO films and various substrates. This resistance is much larger than expected from the acoustic impedance mismatch model and gives a thermal time constant in the nanosecond range for typical YBCO films. Then, there are reports on the design and experimental performance of two different types of high-{Tc} bolometric detectors. One is a conventional bolometer with a gold-black absorber. The other is an antenna coupled microbolometer. The properties of a low-{Tc} microbolometer are also described. The last reports describe accurate measurements and also theoretical modeling of an SIS quasiparticle waveguide mixer for W-band which uses very high quality Ta junctions. The best mixer noise is only 1.3 times the quantum limit. Both the mixer gain and the noise are in quantitative agreement with the quantum theory. 14 refs.

Richards, P.L.

1991-04-01

19

Anticancer Tc9 cells  

PubMed Central

IL-9-producing cytotoxic T (Tc9) cells represent a unique CD8+ T-cell subset. These long-lived immune cells possess the capacity to acquire effector function and home to tumor tissues after adoptive transfer. IL-9 is indispensable for Tc9-mediated superior antitumor response. These findings are highly significant and crucial to achieve advances in T cell-based adoptive therapies.

Lu, Yong; Wang, Qiang; Yi, Qing

2014-01-01

20

Determination of 99 Tc in fuel leachates using extraction chromatography  

Microsoft Academic Search

A simple technique using a combination of cation exchange and solid phase extraction chromatographic resins has been developed for the separation of99Tc from other radionuclides present in nuclear fuel leachates. Quantification of the isolated99Tc is accomplished using liquid scintillation counting. The method provides consistently high recoveries (>96%), generates small amounts of waste compared to classical methods, and requires less analysis

D. L. Moir; D. L. Joseph

1997-01-01

21

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

22

High- Tc bolometers  

SciTech Connect

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 much larger than expected from the acoustic impedance mismatch model and gives a thermal time constant in the nanosecond range for typical YBCO films. Then, there are reports on the design and experimental performance of two different types of high-{Tc} bolometric detectors. One is a conventional bolometer with a gold-black absorber. The other is an antenna-coupled microbolometer. Finally, there is a description of the ultimate performance expected from high-{Tc} bolometers on Si and Si{sub 3}N{sub 4} membrane substrates, with comparisons to other detectors used for thermal imaging. 7 refs.

Richards, P.L.; Clarke, J.; Hu, Q.; Leoni, R.; Lerch, Ph.; Nahum, M.; Verghese, S. (California Univ., Berkeley, CA (United States). Dept. of Physics Lawrence Berkeley Lab., CA (United States)); Beasley, M.R.; Geballe, T.H.; Hammond, R.H.; Rosenthal, P.; Spielman, S.R. (Stanford Univ., CA (United States). Dept. of Applied Physics); Char, K.; Cole, B.F.; Newman, N.; Sachtjen, S.A. (Conductus, Inc., Sunnyvale, C

1991-06-01

23

New measurement of excitation functions for (d,x) reactions on (nat)Mo with special regard to the formation of (95m)Tc, (96m+g)Tc, (99m)Tc and (99)Mo.  

PubMed

Cross-sections for the deuteron-induced reactions on natural molybdenum leading to (93m)Tc, (93m+g)Tc, (94)Tc, (94m)Tc, (95)Tc, (95m)Tc, (96m+g)Tc, (99m)Tc, (99)Mo, (101)Mo, (90m+g)Nb, (92m)Nb, (95)Nb and (89m+g)Zr were measured in the energy range 3.0-19.6 MeV on the cyclotron U-120 M in the Institute of Nuclear Physics AS CR. Special attention was paid to excitation functions and thick target yields for the formation of (95m)Tc, a suitable tracer for (99)Tc, of (96m+g)Tc, which might be used as a beam monitor, and of (99m)Tc and (99)Mo, the most widespread radionuclide generator pair in nuclear medicine. If appropriate, obtained data are compared with the heretofore published cross-sections. PMID:20691603

Lebeda, Ondrej; Fikrle, Marek

2010-12-01

24

New measurement of excitation functions for (p,x) reactions on (nat)Mo with special regard to the formation of (95m)Tc, (96m+g)Tc, (99m)Tc and (99)Mo.  

PubMed

Cross-sections for the proton induced reactions on natural molybdenum leading to (93m)Tc, (93m+g)Tc, (94)Tc, (94m)Tc, (95)Tc, (95m)Tc, (96m+g)Tc, (99m)Tc, (90)Mo, (93m)Mo, (99)Mo, (90m+g)Nb, (92m)Nb, (95)Nb and (89m+g)Zr were measured in the proton energy range 8.4-37.1MeV on the cyclotron U-120M at the Institute of Nuclear Physics AS CR. Special attention was paid to excitation functions and thick target yields for the formation of (95m)Tc, a suitable tracer for (99)Tc, of (96m+g)Tc, which was proposed as a proton beam monitor, and of (99m)Tc and (99)Mo, the most widespread radionuclide generator pair in nuclear medicine. If appropriate, obtained data are compared with the heretofore published cross-sections. PMID:20605475

Lebeda, Ondrej; Pruszy?ski, Marek

2010-12-01

25

Telemetry/Telecommand (TM/TC) processor study  

NASA Astrophysics Data System (ADS)

The functions of a telemetry/telecommand (TM/TC) processor for ESA ESGE are established. Functions performed by the TC front end equipment (FEE) include video signal generation, interface with the RF part, telecomand processing interface with the master test processor, self test, and local mode. Functions performed by the TM FEE include video signal, telemetry processing, interface with the master test processor, self test, and operator interface. Functions common to TC and TM FEE are time management, telecommand monitoring, local recording, and simulation of the operational links. An architecture with two processors is proposed.

Carrasco, J. F.

1984-01-01

26

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

27

Pairing theory of high Tc and low Tc superconductors  

NASA Astrophysics Data System (ADS)

New solutions for Tc, the order parameter, and the density of states are obtained, based on the fact that pairs are formed within the pairing interaction range, TD (Debye), via the BCS pairing theory (not the BCS results). They are valiid for all ify = {T D}/{?T c}, and are applicable to low Tc (LTC) and high Tc (HTS) superconductors. The order parameter variation with y is shown to account for all features of HTS. A new density of states via the zero order parameter outside the pairing interaction range is found to account for low energy states observed in HTS. For large y (LTS), the BCS results are reproduced.

Sang, Boo Nam

1994-09-01

28

Generations.  

PubMed

Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession. PMID:16623137

Chambers, David W

2005-01-01

29

High Tc superconducting IR detectors  

NASA Astrophysics Data System (ADS)

Infrared detectors based upon high transition temperature ('high Tc') superconductors include superconducting transition edge microbolometers, nonequilibrium photoeffect detectors and photon-assisted tunneling detectors. Superconducting transition edge microbolometers offer moderate performance as individual detectors; a potential application is for large two-dimensional staring focal plane arrays. Experimental search for the nonequilibrium photoeffect in high Tc superconductors reveals unwanted bolometric signals. Photon-assisted tunneling in theory provides very high performance, but no experimental data are available.

Kruse, Paul W.

1990-10-01

30

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

31

Graphoepitaxial high-Tc SQUIDs  

NASA Astrophysics Data System (ADS)

The fabrication process and physical properties of graphoepitaxially engineered high-Tc direct current superconducting quantum interferometer devices (DC SQUIDs) are studied. Double buffer layers, each comprising a graphoepitaxial seed layer of YBa2Cu3O7?x and an epitaxial blocking layer of SrTiO3, were deposited over textured step edges on (001) surfaces of MgO substrates. Scanning electron microscopy and high-resolution transmission electron microscopy were used to investigate the microstructural properties of DC SQUIDs with graphoepitaxial Josephson junctions. Both direct coupled and inductively coupled high-Tc DC SQUIDs with graphoepitaxial step edge junctions and flux transformers were studied.

Faley, M. I.; Meertens, D.; Poppe, U.; Dunin-Borkowski, R. E.

2014-05-01

32

BBN TC2000 architecture and programming models.  

National Technical Information Service (NTIS)

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 impleme...

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

1990-01-01

33

Superconductivity and the Fermi surface of Tc  

Microsoft Academic Search

Results of bandstructure calculations of Tc, which has a HCP lattice structure, are used to calculate the superconducting transition temperature Tc and the Fermi surface of the metal. The strong-scattering theory of Gaspari and Gyorffy (1972) is used in conjunction with McMillan's formula (1968) to calculate Tc in the spherical band approximation. As the bandstructure calculations were made for potentials

R. Asokamani; K. Iyakutti

1980-01-01

34

Tumor-specific IL-9-producing CD8+ Tc9 cells are superior effector than type-I cytotoxic Tc1 cells for adoptive immunotherapy of cancers.  

PubMed

Because cytokine-priming signals direct CD8(+) T cells to acquire unique profiles that affect their ability to mediate specific immune responses, here we generated IL-9-skewed CD8(+) T (Tc9) cells by priming with Th9-polarized condition. Compared with type-I CD8(+) cytotoxic T (Tc1) cells, Tc9 secreted different cytokines and were less cytolytic in vitro but surprisingly elicited greater antitumor responses against advanced tumors in OT-I/B16-OVA and Pmel-1/B16 melanoma models. After adoptive transfer, Tc9 cells persisted longer and differentiated into IFN-?- and granzyme-B (GrzB)-producing cytolytic Tc1-like effector cells. Phenotypic analysis revealed that adoptively transferred Tc9 cells secreted IL-2 and were KLRG-1(low) and IL-7R?(high), suggesting that they acquired a signature of "younger" phenotype or became long-term lived cells with capacity of self-renewal. Our results also revealed that Tc9-mediated therapeutic effect critically depended on IL-9 production in vivo. These findings have clinical implications for the improvement of CD8(+) T-cell-based adoptive immunotherapy of cancers. PMID:24469818

Lu, Yong; Hong, Bangxing; Li, Haiyan; Zheng, Yuhuan; Zhang, Mingjun; Wang, Siqing; Qian, Jianfei; Yi, Qing

2014-02-11

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

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.

Mirzadeh, Saed (Knoxville, TN); Knapp, Jr., Furn F. (Oak Ridge, TN); Collins, Emory D. (Knoxville, TN)

1998-01-01

37

Simulation of the direct production of 99mTc at a small cyclotron  

NASA Astrophysics Data System (ADS)

Usually 99mTc is produced indirectly through generator 99Mo/99mTc. In the present study, the direct production of this radioisotope by charged particle irradiation was investigated using Monte Carlo method. After scouting of the reactions that produce 99mTc, excitation functions of these reactions were predicted by optical model components in the TALYS-1.6 code. Suitable energy range of projectile for this production was selected by spotting of maximum cross section and minimum impurity due to other emission channels. Then target geometry was designed based on stopping power calculation by the SRIM code. Thick target yield of 100Mo(p,2n)99mTc, 98Mo(p,?)99mTc and natMo(p,x)99mTc reactions was predicted by the result of excitation function and stopping power calculations. Finally, 100Mo(p,2n)99mTc reaction was selected as a primary reaction for the direct production of 99mTc and its process was simulated by employing the MCNPX code to calculate the energy distribution of proton in the 100Mo target body and estimation of residual nuclei during irradiation. Good agreement was obtained between the experimental, the theoretical, and the simulation-based (analytical and directly) production yields. This study demonstrated that Monte Carlo provides a method for the design and optimization of targets for the radionuclide production purposes.

Eslami, M.; Kakavand, T.

2014-06-01

38

Interdecadal changes in summer TC activity in East China Sea  

NASA Astrophysics Data System (ADS)

The study analyzed the time series of the tropical cyclone (TC) frequencies which passed through the East China Sea between July and September from 1963 to 2012. The result of applying the statistical change-point analysis to this time series shows that a climate regime shift occurred in 1983 when the TC frequencies which pass the East China Sea area started increasing. The study then analyzed the average difference after 1983 (1984-2012) and before 1983 (1963-1983). The TC genesis frequency shows a tendency in mainly appearing in the tropical and subtropical Northwestern Pacific between 1963 and 1983 and the southern part between 1984 and 2012. The TC passage frequency shows a pattern that the TCs move from the far northeast sea of Philippines and change direction to Korea and Japan, passing through the East China Sea between 1984 and 2012. Meanwhile, the TC passage frequency shows a pattern which moves from the far southeast sea of the Philippines to southern China in the west direction in the previous period (1963-1983). These TC movement patterns coincide with the development status of the subtropical western North Pacific high (SWNPH) which averages for each period. It shows that the SWNPH in the second period stays away from the SWNPH in the second period from the northeast direction, but that the SWNPH in the first period expands to western Taiwan. This study analyzes the difference between the two periods in the 500-hPa streamline to understand the changes in such TC activities in the two groups. The anomalous anticyclonic circulations centered in the southern part of Japan are fortified in most of the subtropical Northwestern Pacific. The anomalous southerlies from the anomalous circulations are outstanding in the East China Sea area, Korea, and Japan. Therefore, the TCs generated in the tropical and subtropical Northwestern Pacific move along with the anomalous steering flow (anomalous southwesterlies) and up toward the East China Sea area, Korea, and Japan. The anomalous anticyclonic circulations are fortified in most of the subtropical Northwestern Pacific areas, but the anomalous cyclonic circulations are strengthened in the tropical Northwestern Pacific below 15° N, causing the generation of TCs mainly in the northwestern part of the tropical and subtropical Northwestern Pacific between 1963 and 1983, and in the southeastern part between 1984 and 2012.

Choi, Ki-Seon; Cha, Yu-Mi; Kang, Sung-Dae; Kim, Hae-Dong

2014-04-01

39

Circuit design for a high-Tc Josephson sampler  

Microsoft Academic Search

We propose a high-speed and high-sensitivity sampler circuit using high Tc superconducting (HTS) Josephson junctions. This circuit consists of five non-latching junctions, superconducting lines and a superconducting ground-plane. A main feature of this circuit is a non-latching comparator junction whose switching generates a circulating current in a superconducting loop. Computer simulation and prototype layout were performed to study its ability

Mutsuo Hidaka; J. S. Tsai

1995-01-01

40

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

Microsoft Academic Search

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 ⁹⁹Mo, {sup 99m}Tc use has grown steadily over the past 20 yr. Despite the widespread demand for

R. G. Bennett; W. K. Terry; S. B. Grover

1997-01-01

41

Aberrant function of the Ras-related protein TC21/R-Ras2 triggers malignant transformation.  

PubMed Central

Although the human Ras proteins are members of a large superfamily of Ras-related proteins, to date, only the proteins encoded by the three mammalian ras genes have been found to possess oncogenic potential. Among the known Ras-related proteins, TC21/R-Ras2 exhibits the most significant amino acid identity (55%) to Ras proteins. We have generated mutant forms of TC21 that possess amino acid substitutions analogous to those that activate Ras oncogenic potential [designated TC21(22V) and TC21(71L)] and compared the biological properties of TC21 with those of Ras proteins in NIH 3T3 and Rat-1 transformation assays. Whereas wild-type TC21 did not show any transforming potential in vitro, both TC21(22V) and TC21(71L) displayed surprisingly potent transforming activities that were comparable to the strong transforming activity of oncogenic Ras proteins. Like Ras-transformed cells, NIH 3T3 cells expressing mutant TC21 proteins formed foci of morphologically transformed cells in monolayer cultures, proliferated in low serum, formed colonies in soft agar, and developed progressive tumors in nude mice. Thus, TC21 is the first Ras-related protein to exhibit potent transforming activity equivalent to that of Ras. Furthermore, mutant TC21 proteins also stimulated constitutive activation of mitogen-activated protein kinases as well as transcriptional activation from Ras-responsive promoter elements (Ets/AP-1 and NF-kappa B). We conclude that aberrant TC21 function may trigger cellular transformation via a signal transduction pathway similar to that of oncogenic Ras and suggest that deregulated TC21 activity may contribute significantly to human oncogenesis. Images

Graham, S M; Cox, A D; Drivas, G; Rush, M G; D'Eustachio, P; Der, C J

1994-01-01

42

Interaction of granite with Tc(IV) and Tc(VII) in aqueous solution.  

National Technical Information Service (NTIS)

The behaviour of technetium in granite-groundwater systems under reducing conditions was investigated. The anion TcO(sub 4)(sup -) was reduced to Tc(IV) and simultaneously precipitated as TcO(sub 2)xnH(sub 2)O on the granite surfaces. The electron sources...

T. E. Eriksen D. Cui

1991-01-01

43

Quantitative simultaneous In-111/Tc-99m planar imaging in a long-bone infection phantom  

NASA Astrophysics Data System (ADS)

In-111-white-blood-cell and Tc-99m-sulfur-colloid dual-radionuclide imaging are frequently utilized in the evaluation of patients with suspected osteomyelitis. We have developed a quantitative planar imaging method in which Tc-99m and In-111 scans are acquired simultaneously in accurate spatial registration. Long, thin tubes containing only In-111 or Tc-99m were first imaged in a list mode within a water bath inclined with respect to the water surface; from these, 12 energy spectra corresponding to different Tc/In ratios were synthesized. Triple-energy-window (TEW) parameters for scatter and radionuclide crosstalk correction, including scatter windows and weights, were optimized using 100 noise realizations of each of the spectra (1200 total). A long-bone phantom containing a simulated infection site was then imaged in water with five In/Tc ratios; 100 noise realizations of two conjugate-view images were generated from each acquisition (500 total). Two regions of interest (ROIs) were defined, and the ratio of In/Tc count ratios in these two ROIs was evaluated with and without the TEW scatter correction and geometric mean attenuation compensation. The average bias improved from 17.2% to 5.3%, with comparable precision. TEW corrections with non-optimized but practical energy windows also improved the bias to 6.4%. Compared with subjective visual assessment, quantitation of In-111/Tc-99m ratios may improve diagnostic accuracy and could eventually permit grading of osteomyelitis.

Zhu, Xuping; Park, Mi-Ae; Gerbaudo, Victor H.; Moore, Stephen C.

2007-12-01

44

Power Systems Development Facility Gasification Test Campaing TC14  

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 TC14 of the PSDF gasification process. TC14 began on February 16, 2004, and lasted until February 28, 2004, accumulating 214 hours of operation using Powder River Basin (PRB) subbituminous coal. The gasifier operating temperatures varied from 1760 to 1810 F at pressures from 188 to 212 psig during steady air blown operations and approximately 160 psig during oxygen blown operations.

Southern Company Services

2004-02-28

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

Tc-99m Labeled carrier for imaging  

DOEpatents

Novel radionuclide imaging agents, having particular application for lymphangiography are provided by non-covalently binding Tc-99m to a pharmaceutically acceptable cross-linked polysaccharide. Upon injection of the Tc-99m labeled polysaccharide into the blood stream, optimum contrast can be obtained within one hour.

Henze, Eberhard (Santa Monica, CA)

1984-01-01

47

Tc-99m hydroxymethylene diphosphonate and Tc-99m methylene diphosphonate: biological and clinical comparison: concise communication  

SciTech Connect

The biologic and imaging characteristics of Tc-99m HMDP and Tc-99m MDP were compared in ten patients. Tc-99m HMDP blood levels were marginally lower at 4 hr. There were no significant differences in 4-hr urinary clearance, normal bone-to-background ratio, or ratio of lesion to normal bone. Relative image quality comparison showed a slight preference for Tc-99m HMDP. Biologically Tc-99m HMDP compares favorably with Tc-99m MDP. Under the conditions of this study, Tc-99m HMDP image quality is at least comparable to that of Tc-99m MDP.

Littlefield, J.L.; Rudd, T.G.

1983-06-01

48

Tc-99m hydroxymethylene diphosphonate and Tc-99m methylene diphosphonate: biological and clinical comparison: concise communication  

SciTech Connect

The biologic and imaging characteristics of Tc-99m HMDP and Tc-99m MDP were compared in ten patients. Tc-99m HMDP blood levels were marginally lower at 4 h. There were no significant differences in 4-h urinary clearance, normal bone-to-background ratio, or ratio of lesion to normal bone. Relative image quality comparison showed a slight preference for Tc-99m HMDP. Biologically Tc-99m HMDP compares favorably with Tc-99m MDP. Under the conditions of this study, Tc-99m HMDP image quality is at least comparable to that of Tc-99m MDP.

Littlefield, J.L.; Rudd, T.G.

1983-06-01

49

Radionuclide Generators  

NASA Astrophysics Data System (ADS)

Radionuclide generator systems continue to play a key role in providing both diagnostic and therapeutic radionuclides for various applications in nuclear medicine, oncology, and interventional cardiology. Although many parent/daughter pairs have been evaluated as radionuclide generator systems, there are a relatively small number of generators, which are currently in routine clinical and research use. Essentially every conceivable approach has been used for parent/separation strategies, including sublimation, thermochromatographic separation, solvent extraction, and adsorptive column chromatography. The most widely used radionuclide generator for clinical applications is the 99Mo/99mTc generator system, but recent years have seen an enormous increase in the use of generators to provide therapeutic radionuclides, which has paralleled the development of complementary technologies for targeting agents for therapy and in the general increased interest in the use of unsealed therapeutic radioactive sources. More recently, use of the 68Ge/68Ga generator is showing great potential as a source of positron-emitting 68Ga for positron emission tomography (PET)/CT imaging. Key advantages for the use of radionuclide generators include reasonable costs, the convenience of obtaining the desired daughter radionuclide on demand, and availability of the daughter radionuclide in high specific activity, no-carrier added form.

Rösch, F.; Knapp, F. F. (Russ)

50

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

51

Secrets of Soil Survival Revealed by the Genome Sequence of Arthrobacter aurescens TC1  

PubMed Central

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.

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

2006-01-01

52

Friction phenomena in low- Tc and high- Tc superconductor winding systems  

NASA Astrophysics Data System (ADS)

Friction experiments are reported for relative motion between NbTi/Cu windings coated with formvar, i.e. for a superconductor with low transition temperature ( Tc). A heat flow meter technique is used based on ZNMF heat piping in He II ( ZNMF = zeronetmassflow). The friction factors obtained are consistent with results deduced from other techniques. From the data obtained, adiabatic, limiting displacements dad (at quench) are calculated for high transition temperature (high Tc) composite conductors. The comparison with low Tc results shows that dad will not be a critical parameter for the present winding friction model at high Tc.

Kim, Y. I.; Caspi, S.; Ravikumar, K. V.; Frederking, T. H. K.

53

A monoallelic deletion of the TcCRT gene increases the attenuation of a cultured Trypanosoma cruzi strain, protecting against an in vivo virulent challenge.  

PubMed

Trypanosoma cruzi calreticulin (TcCRT) is a virulence factor that binds complement C1, thus inhibiting the activation of the classical complement pathway and generating pro-phagocytic signals that increase parasite infectivity. In a previous work, we characterized a clonal cell line lacking one TcCRT allele (TcCRT+/-) and another overexpressing it (TcCRT+), both derived from the attenuated TCC T. cruzi strain. The TcCRT+/- mutant was highly susceptible to killing by the complement machinery and presented a remarkable reduced propagation and differentiation rate both in vitro and in vivo. In this report, we have extended these studies to assess, in a mouse model of disease, the virulence, immunogenicity and safety of the mutant as an experimental vaccine. Balb/c mice were inoculated with TcCRT+/- parasites and followed-up during a 6-month period. Mutant parasites were not detected by sensitive techniques, even after mice immune suppression. Total anti-T. cruzi IgG levels were undetectable in TcCRT+/- inoculated mice and the genetic alteration was stable after long-term infection and it did not revert back to wild type form. Most importantly, immunization with TcCRT+/- parasites induces a highly protective response after challenge with a virulent T. cruzi strain, as evidenced by lower parasite density, mortality, spleen index and tissue inflammatory response. TcCRT+/- clones are restricted in two important properties conferred by TcCRT and indirectly by C1q: their ability to evade the host immune response and their virulence. Therefore, deletion of one copy of the TcCRT gene in the attenuated TCC strain generated a safe and irreversibly gene-deleted live attenuated parasite with high immunoprotective properties. Our results also contribute to endorse the important role of TcCRT as a T. cruzi virulence factor. PMID:24551259

Sánchez-Valdéz, Fernando J; Pérez Brandán, Cecilia; Ramírez, Galia; Uncos, Alejandro D; Zago, M Paola; Cimino, Rubén O; Cardozo, Rubén M; Marco, Jorge D; Ferreira, Arturo; Basombrío, Miguel Ángel

2014-02-01

54

A comparison of rat SPECT images obtained using 99mTc derived from 99Mo produced by an electron accelerator with that from a reactor  

NASA Astrophysics Data System (ADS)

Recent shortages of molybdenum-99 (99Mo) 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 99Mo from which technetium-99m (99mTc) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced 99mTc with those obtained using 99mTc from a commercial generator were compared. Disks of 100Mo were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of 99Mo per disk. After target dissolution, a NorthStar ARSII unit was used to separate the 99mTc, 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 99mTc from a standard reactor 99Mo generator. The efficiency of 99Mo-99mTc separation was typically greater than 90%. This study demonstrated the delivery of 99mTc 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 99mTc were comparable. High-power electron accelerators are an attractive option for producing 99Mo on a national scale.

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

2013-05-01

55

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

2013-05-01

56

Evaluation of a 99mTc-antimyosin kit for myocardial infarct imaging.  

PubMed

The Fab fragment of a mouse monoclonal antibody AM(3-48) that recognizes alpha and beta-heavy chains of human atrial and ventricular myosin and beta-heavy chain of human slow skeletal muscle myosin [CardioVisionTM] was labeled with 99mTc using stannous reductant in a simple, instant kit method. The infarcted heart uptake in dogs of 99mTc-AM(3-48)Fab' was compared with that of established radiopharmaceuticals routinely used for cardiac imaging in humans. The dog infarct was induced by bringing a catheter from the femoral artery to the coronary artery where an artificial blood clot was generated. The 99mTc-AM(3-48)Fab' preparation was selectively taken up by infarcted myocardium, resulting in diagnostic quality images of the infarcted area as early as 6 hour post-injection, rendering CardioVisionTM particularly useful for SPECT imaging. Good agreement was found between the images obtained with 99mTc-Pyrophosphate and those obtained with 99mTc-AM(3-48)Fab', while the infarcted area was clearly delineated as a cold spot with 99mTc-MIBI or 201 Tl-thallous chloride. The biodistribution of 99mTc-AM(3-48)Fab' was also studied in healthy and isoproterenol-infarcted rats, from which dosimetry values in man were extrapolated. The data indicate that the kidneys will receive the highest radiation dose and that they will be the main contributors to the total radiation burden, which was estimated at 0.005 rad/mCi. PMID:7632767

Rousseau, J; Sikorska, H M; Gervais, A; Bisson, G; Margaron, P; Lamoureux, G; Mirza, S A; van Lier, J E

1994-12-01

57

Principali componenti di uno scanner TC  

Microsoft Academic Search

\\u000a I requisiti strutturali di una sala in cui si svolge attività diagnostica mediante tomografia computerizzata variano in funzione\\u000a del tipo di apparecchiatura prevista e della tipologia di esami che saranno effettuati. In linea generale, una diagnostica\\u000a TC prevede tre aree distinte.\\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Sala diagnostica: è il locale nel quale sono posizionati lo scanner TC (gantry e lettino porta-paziente), il generatore,

Simona Corona; Silvia Cavaliere; Cristiana Baggiani

58

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

59

Optimisation of Simultaneous Tl-201/Tc-99m Dual Isotope Reconstruction with Monte-Carlo-Based Scatter Correction  

PubMed Central

Simultaneous Tl-201/Tc-99m dual isotope myocardial perfusion SPECT is seriously hampered by down-scatter from Tc-99m into the Tl-201 energy window. This paper presents and optimises the ordered-subsets-expectation-maximisation-(OS-EM-) based reconstruction algorithm, which corrects the down-scatter using an efficient Monte Carlo (MC) simulator. The algorithm starts by first reconstructing the Tc-99m image with attenuation, collimator response, and MC-based scatter correction. The reconstructed Tc-99m image is then used as an input for an efficient MC-based down-scatter simulation of Tc-99m photons into the Tl-201 window. This down-scatter estimate is finally used in the Tl-201 reconstruction to correct the crosstalk between the two isotopes. The mathematical 4D NCAT phantom and physical cardiac phantoms were used to optimise the number of OS-EM iterations where the scatter estimate is updated and the number of MC simulated photons. The results showed that two scatter update iterations and 105 simulated photons are enough for the Tc-99m and Tl-201 reconstructions, whereas 106 simulated photons are needed to generate good quality down-scatter estimates. With these parameters, the entire Tl-201/Tc-99m dual isotope reconstruction can be accomplished in less than 3 minutes.

Kangasmaa, Tuija; Kuikka, Jyrki; Sohlberg, Antti

2012-01-01

60

TcI/TcII co-infection can enhance Trypanosoma cruzi growth in Rhodnius prolixus  

PubMed Central

Background Rhodnius prolixus is an obligate haematophagous insect and one of the most important vectors of Trypanosoma cruzi, the causative agent of Chagas disease in the Americas. T. cruzi is a highly variable parasite which is not transmitted in the same efficiency by the different triatomine vectors. Because different T. cruzi genotypes are aetiopathologically divergent, further elucidation of the transmission abilities of different Chagas disease vectors is extremely important. Findings In the present study, the growth behaviour of two T. cruzi isolates, MDID/BR/1993/C45 (TcI) and TBRA/BR/1999/JCA3 (TcII), sharing the same microhabitat (intestinal tract) in single and mixed infections, was examined. The distribution patterns and parasite population densities were evaluated at 7, 14 and 21 days after feeding (daf) by quantification of parasites using Neubauer haemocytometric measurements and mini-exon PCR to identify TcI and TcII subpopulations. Parasitic colonization in the small intestine was more successful in the mixed infection model than the single infection models at 21 daf. In the rectal lumen and wall, the growth behaviour of the mixed infection was similar to that of the TcI group, although the total parasite number was lower. In the TcII group, no metacyclic trypomastigote forms were found. PCR analysis of the contents of each dissected region showed different genotype fractions in the mixed infection model, in which TcI seemed to be the predominant isolate. Conclusion The different growth behaviour of the TcI and TcII isolates in single and mixed infection models demonstrated that possibly an intraspecific factor modulates parasitic development in the intestine of R. prolixus.

2014-01-01

61

Use of Tc-99m-galactosyl-neoglycoalbumin (Tc-NGA) to determine hepatic blood flow  

SciTech Connect

Tc-NGA is a new liver radiopharmaceutical which binds to a hepatocyte-specific membrane receptor. Three characteristics of Tc-NGA can be exploited in the measurement of hepatic blood flow (HBF): 1) ability to alter the affinity of Tc-NGA for its receptor by changing the galactose: albumin ratio; 2) ability to achieve a high specific activity with Tc-99m labeling; and 3) ability to administer a high molar dose of Tc-NGA without physiologic side effects. In addition, kinetic modeling of Tc-NGA dynamic data can provide estimates of hepatic receptor concentration. In experimental studies in young pigs, HBF was determined using two techniques: 1) kinetic modeling of dynamic data using moderate affinity, low specific activity Tc-NGA (Group A, n=12); and 2) clearance (CL) technique using high affinity, high specific activity Tc-NGA (Group B, n=4). In both groups, HBF was determined simultaneously by continuous infusion of indocyanine green (CI-ICG) with hepatic vein sampling. Regression analysis of HBF measurements obtained with the Tc-NGA kinetic modeling technique and the CI-ICG technique (Group A) revealed good correlation between the two techniques (r=0.802, p=0.02). Similarly, HBF determination by the clearance technique (Group B) provided highly accurate measurements when compared to the CI-ICG technique. Hepatic blood flow measurements by the clearance technique (CL-NGA) fell within one standard deviation of the error associated with each CI-ICG HBF measurement (all CI-ICG standard deviations were less than 10%).

Stadalnik, R.C.; Vera, D.R.; Woodle, E.S.; Hutak, D.P.; Ward, R.E.; Krohn, K.A.

1984-01-01

62

Development of more efficacious /sup 99m/Tc organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures. Progress report, May 1, 1983-January 1, 1986  

SciTech Connect

The formation of many different technetium complexes in the Tc(NaBH4)-HEDP, Tc(NaBH4)-MDP, and Tc(NaBH4)-DMAD systems has been clearly demonstrated by HPLC-separation of reaction mixtures. The dramatically different biodistributions exhibited by the various complexes strongly suggests that an improved skeletal radiopharmaceutical would result if the single technetium complex which exhibits the optimum biodistribution properties is administered to the patient. The influence of pH, time, concentrations of TcO4 and ligand, and the nature of reductant on the relative amounts of the different complexes formed were investigated. Electrochemical reduction offers a means of possibly generating a desired complex in very high yield due to the precision with which redox potential can be controlled. Additionally, we have developed HPLC methods with uv and electrochemical detection for the determination of total TcO4 in eluents from the ZZMo//sup 99m/Tc radionuclide generator. The inadequacy of current theory to accurately predict total TcO4 in generator eluents was demonstrated in that the concentration of total TcO4 is a major factor determining the yield of individual Tc-diphosphonate complexes. Spectroelectrochemistry proved an effective technique to study the redox properties of Tc-complexes. 18 refs., 10 figs., 1 tab.

Heineman, W.R.

1986-01-01

63

Adolescent Services & the TC. Chapter 6.  

ERIC Educational Resources Information Center

This document contains seven papers from the ninth World Conference of Therapeutic Communities (TCs) that deal with adolescent clients and TCs. Papers include: (1) Preliminary Consideration on "Adolescence and the TC" (David Deitch); (2) "Daytop's Full Service Adolescent Treatment Program" (Charles Devlin and Lois Morris); (3) "Adolescent…

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

64

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.

65

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

66

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

67

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.

68

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan.  

PubMed

Using a sector-field ICP-MS the vertical distributions of the (99)Tc concentration and (99)Tc/(137)Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The (99)Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m(3), no greater than the estimated background level. Relatively high (99)Tc/(137)Cs activity ratios (10-12 × 10(-4)) would be caused by the inflow of the high-(99)Tc/(137)Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The (99)Tc concentration and the (99)Tc/(137)Cs activity ratio in water column showed gradual decreases with depth. Our results implied that (99)Tc behaves in a more conservative manner than (137)Cs in marine environments. PMID:21555170

Nakanishi, Takahiro; Zheng, Jian; Aono, Tatsuo; Yamada, Masatoshi; Kusakabe, Masashi

2011-08-01

69

Development of more efficacious TC-99M organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures. Progress report, May 1, 1983-April 1, 1984  

SciTech Connect

It has been demonstrated that formulation variables (pH, TcO/sub 4//sup -/ concentration, and ligand-to-metal ratio) influence the chromatographic distribution of the components of a Tc-hydroxyethylidene diphosphonate (HEDP) mixture prepared by the NaBH/sub 4/ reduction of TcO/sub 4//sup -/ in the presence of HEDP. The use of alternate reductants for TcO/sub 4//sup -/ (i.e., SnCl/sub 2/, and electrode) not only alters the relative proportion of the Tc-HEDP components formed, but produces new complexes not previously seen (based on chromatographic retention time data). Thus, a systematic evaluation has been undertaken of the SnCl/sub 2/ and electrochemical reduction preparations that is similar to that conducted for Tc(NaBH/sub 4/)-HEDP mixtures. High performance liquid chromatography with electrochemical detection has been utilized to separate components of a Tc(NaBH4)-methylene diphosphonate mixture. All Tc components of the mixture are reducible at a mercury electrode and hydrodynamic voltammetric data is being generated. Stripping chronocoulometry has been developed as a novel variation of anodic stripping voltammetry in order to increase precision in the analytical determination of TcO/sub 4//sup -/ in aqueous solution. Pilot studies to evaluate the operating parameters of /sup 99/Mo//sup 99m/Tc/ generators and to investigate two new diphosphonate ligands in the preparation of technetium skeletal imaging radiopharmaceutical analogs have been initiated.

Heineman, W.R.

1984-01-01

70

Characteristics of Tc-99m-complexes of large tetraphosphonates  

SciTech Connect

Tetraphoshonate derivates of dicyclopentadiene (TPDCPD), norbornane (TPNB) and piperazine (TPP) inhibit boiler scale by forming stable ''C-clamp'' chelate structures with calcium and other metals. Their large size and molecular composition of several phosphate groups should favor the formation of Tc-99m chelates with greater chemical purity than the Tc-99m diphosphonates used for clinical skeletal imaging. All three were evaluated and compared to Tc-99-m-MDP as skeletal radiopharmaceuticals. TPDCPD and TPNB rapidly formed stable complexes with Tc-99m (>90%) in aqueous solution at pH3. Tc-99m-TPP was unstable after complexation. Skeletal uptake of Tc-99m-TPNB (41.7 +- 2.5% ID) in rats 2 hours post-injection was equivalent to Tc-99m-MDP (39.4 +- 7.4% ID) while Tc-99m-TPDCPD was slightly less (35.9 +- 2.7% ID). Non-osseous uptake of these ligands was minimal (eg., liver, < 0.2% ID/1% BWt). In rabbits, Tc-99m-TPNB and -TPDCPD gave skeletal uptakes less than (approx. =75%) Tc-99m-MDP. Both chelates had blood clearance rates nearly identical to Tc-99m-MDP despite differences in their molecular structure and ligand size. Qualitative planar images of the rabbit skeleton using Tc-99m-TPNB and Tc-99m-MDP were comparable. Although the Tc99m-tetraphosphate chelates are not superior diagnostic skeletal imaging agents as Tc-99m-MDP their skeletal selectivity, rapid blood clearance, stability and apparent chelate purity suggest they may form useful therapeutic chelates with various particulate emitting radionuclides.

Volkert, W.A.; Simon, J.; Wilson, D.A.; Edwards, B.; McKenzie, E.H.; Oberle, P.; Holmes, R.A.

1984-01-01

71

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

72

Synthesis of trevorite to capture Tc  

SciTech Connect

Spinel containing technetium can be used to prevent Tc volatilization during vitrification of radioactive waste. Spinel dissolves in glass at elevated temperatures. This study focuses on the synthesis of spinel and the retention of rhenium, a nonradioactive surrogate for Tc in the crystals. To produce trevorite, a nickel-iron spinel (NiFe2O4), Fe and Ni nitrates were mixed with alkali nitrates along with Al(OH)3 and heated to 500 to 800°C. The trevorite content in samples (up to 40 mass%) was measured with x-ray diffraction. Viable samples were rerun with KReO4. Scanning electron microscopy-energy dispersive spectroscopy detected that Re became partly immobilized in spinel-forming crystals.

Tsui, Colin

2011-09-02

73

High-Tc superconducting small antennas  

Microsoft Academic Search

The authors describe the designs of and report experimental results for one- and two-element high-Tc superconducting small antennas composed of self-resonant helical radiators and quarter-wave matching circuits. A 500-MHz-band antenna using a ?\\/40 (? is the free-space wavelength) radiator fabricated with Bi(Pb)SrCaCuO bulk realized a gain of -1.2 dBi, which indicates that this antenna achieves a high frequency of 70%.

K. Itoh; O. Ishii; Y. Nagai; N. Suzuki; Y. Kimachi; O. Michikami

1993-01-01

74

High- Tc thin-film magnetometer  

SciTech Connect

We have constructed and tested high-{Tc} magnetometers by coupling a high-{Tc} thin-film Superconducting QUantum Interference Device (SQUID) to two different high-{Tc} thin-film flux transformers. The SQUID was made from Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8+y} films grown on MgO, with junctions consisting of native grain boundaries. The flux transformers were made from YBa{sub 2}Cu{sub 3}O{sub 7-x}, and each had 10-turn input coils and a single-turn pickup loop. The first transformer, which was patterned with a combination of shadow masks and photolithography, yielded a magnetic field gain of about {minus}7.5, functioned up to 79 K, and gave a magnetic field sensitivity B{sub N} (10 Hz) {approx} 3.1 pT Hz{sup {minus}1/2}at 38 K. The second transformer, which was patterned entirely by photolithography, yielded a gain of about {minus}8.7, functioned up to 25 K, and had a sensitivity B{sub N} (10 Hz) {approx} 3.5 pT Hz{sup {minus}1/2} at 4.2 K. In both cases, the limiting noise arose in the SQUID. 10 refs., 5 figs., 1 tab.

Miklich, A.H.; Wellstood, F.C.; Kingston, J.J.; Clarke, J. (Lawrence Berkeley Lab., CA (USA)); Colclough, M.S. (Conductus, Inc., Sunnyvale, CA (USA)); Cardona, A.H.; Bourne, L.C.; Olson, W.L.; Eddy, M.M. (Superconductor Technologies, Inc., Santa Barbara, CA (USA))

1990-09-01

75

OMPS TC EDR Algorithm: Improvement and Verification  

NASA Astrophysics Data System (ADS)

The Ozone Mapper and Profiler Suite (OMPS) is scheduled to be launched on the NPOESS Preparatory Project (NPP) platform in early 2011. The OMPS will continue monitoring ozone from space, using three instruments, namely the Total Column Mapper (heritage: TOMS), the Nadir Profiler (heritage: SBUV) and the Limb Profiler (heritage: SOLSE/LORE). The Total Column Mapper (TC) sensor images the Earth through a slit, nadir-cell horizontally spaced at 49.5 km cross-track with an along-track reporting interval of 50 km. The total field of view (FOV) cross track is 110 degrees to provide daily global coverage. The TC sensor, a grating spectrometer, provides 0.45 nm spectral sampling across the wavelength range of 300-380 nm. The calibration stability, which is essential to enable long-term ozone monitoring, is maintained by periodic observations of the Sun, using a diffuser to redirect the solar irradiance into the sensor. We describe the data analysis method being presently implemented to retrieve the total column ozone Earth Data Record (EDR) from the radiance data measured by the TC sensor. We discuss the software changes, the test data used to verify the functional performance and the test results.

Novicki, M.; Sen, B.; Hao, X.; Qu, J. J.

2009-12-01

76

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

77

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

78

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

79

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

80

Pretreatment of Tc-Containing Waste and Its Effect on Tc-99 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. (authors)

Aloy, Albert; Kovarskaya, Elena N. [RosAtom, 'V.G. Khlopin Radium Institute' (KRI), 2-nd Murinsky str., 28, Saint Petersburg, 194021 (Russian Federation); Harbour, John R.; Langton, Christine A.; Holtzscheiter, E. William [Savannah River National Laboratory, Washington Savannah River Company, Aiken, SC 29808 (United States)

2007-07-01

81

Physicochemical studies of the reaction of 99mTc with 5,5?-diethyl barbituric acid, adenine, D-glucose and thiobarbituric acid at different temperatures  

NASA Astrophysics Data System (ADS)

The reaction of 99mTc pertechnetate with 5,5?-diethyl barbituric acid, adenine, D-glucose and thiobarbituric acid at different temperatures was studied. The solvent effect on the electronic absorption spectra of the reactions was recorded. The reaction mixtures have been analyzed at different times using TLC and a radiodetctor to show the peaks at the plates. 99mTc pertechnetate is obtained from the Mo generators. It is difficult to separate the complexes in the solid state. The percentage of 99mTc involved in the complexes can be determined. Characterization of the 99mTc complexes as well as the determination of the extent of radiolabeling was done by thin layer chromatography using 0.9% NaCl solution as a solvent. The Rf value of 99TcO4- is (?1). The solvatochromism for the reaction of 99mTc with D-glucose was mainly affected by solute permanent dipole-solvent permanent dipole interaction, the dipolar interaction for the reaction of 99mTc with of 5,5?-diethyl barbituric acid and for the reaction of 99mTc with adenine and thiobarbituric was solute-solvent hydrogen bonding.

Masoud, M. S.; El-Shahat, M. F.; Elkholany, A. S.

2014-06-01

82

Physicochemical studies of the reaction of (99m)Tc with 5,5'-diethyl barbituric acid, adenine, d-glucose and thiobarbituric acid at different temperatures.  

PubMed

The reaction of (99m)Tc pertechnetate with 5,5'-diethyl barbituric acid, adenine, d-glucose and thiobarbituric acid at different temperatures was studied. The solvent effect on the electronic absorption spectra of the reactions was recorded. The reaction mixtures have been analyzed at different times using TLC and a radiodetctor to show the peaks at the plates. (99m)Tc pertechnetate is obtained from the Mo generators. It is difficult to separate the complexes in the solid state. The percentage of (99m)Tc involved in the complexes can be determined. Characterization of the (99m)Tc complexes as well as the determination of the extent of radiolabeling was done by thin layer chromatography using 0.9% NaCl solution as a solvent. The Rf value of (99m)TcO4(-) is (?1). The solvatochromism for the reaction of (99m)Tc with d-glucose was mainly affected by solute permanent dipole-solvent permanent dipole interaction, the dipolar interaction for the reaction of (99m)Tc with of 5,5'-diethyl barbituric acid and for the reaction of (99m)Tc with adenine and thiobarbituric was solute-solvent hydrogen bonding. PMID:24632174

Masoud, M S; El-Shahat, M F; Elkholany, A S

2014-06-01

83

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

84

Fe(II)- and sulfide-facilitated reduction of 99Tc(VII)O4- in microbially reduced hyporheic zone sediments  

NASA Astrophysics Data System (ADS)

Redox-reactive, biogeochemical phases generated by reductive microbial activity in hyporheic zone sediments from a dynamic groundwater-river interaction zone were evaluated for their ability to reduce soluble pertechnetate [99Tc(VII)O4-] to less soluble Tc(IV). The sediments were bioreduced by indigenous microorganisms that were stimulated by organic substrate addition in synthetic groundwater with or without sulfate. In most treatments, 20 ?mol L-1 initial aqueous Tc(VII) was reduced to near or below detection (3.82 × 10-9 mol L-1) over periods of days to months in suspensions of variable solids concentrations. Native sediments containing significant lithogenic Fe(II) in various phases were, in contrast, unreactive with Tc(VII). The reduction rates in the bioreduced sediments increased with increases in sediment mass, in proportion to weak acid-extractable Fe(II) and sediment-associated sulfide (AVS). The rate of Tc(VII) reduction was first order with respect to both aqueous Tc(VII) concentration and sediment mass, but correlations between specific reductant concentrations and reaction rate were not found. X-ray microprobe measurements revealed a strong correlation between Tc hot spots and Fe-containing mineral particles in the sediment. However, only a portion of Fe-containing particles were Tc-hosts. The Tc-hot spots displayed a chemical signature (by EDXRF) similar to pyroxene. The application of autoradiography and electron microprobe allowed further isolation of Tc-containing particles that were invariably found to be ca 100 ?m aggregates of primary mineral material embedded within a fine-grained phyllosilicate matrix. EXAFS spectroscopy revealed that the Tc(IV) within these were a combination of a Tc(IV)O2-like phase and Tc(IV)-Fe surface clusters, with a significant fraction of a TcSx-like phase in sediments incubated with SO42-. AVS was implicated as a more selective reductant at low solids concentration even though its concentration was below that required for stoichiometric reduction of Tc(VII). These results demonstrate that composite mineral aggregates may be redox reaction centers in coarse-textured hyporheic zone sediments regardless of the dominant anoxic biogeochemical processes.

Lee, Ji-Hoon; Zachara, John M.; Fredrickson, James K.; Heald, Steve M.; McKinley, James P.; Plymale, Andrew E.; Resch, Charles T.; Moore, Dean A.

2014-07-01

85

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

86

Retention of 99mTc-DMSA(III) and 99mTc-nanocolloid in different syringes affects imaging quality.  

PubMed

(99m)Tc-dimercaptosuccinic acid [DMSA(III)] and colloidal human serum albumin ((99m)Tc-nanocolloid) are widely used radiopharmaceuticals. Recently, in our institution we encountered image quality problems in DMSA scans after changing the brand of syringes we were using, which triggered us to look into the adsorption properties of syringes from different brands for (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid. We also describe a clinical case in which adsorption of (99m)Tc-DMSA(III) caused inferior imaging quality. DMSA and nanocolloid were labeled with (99m)Tc following manufacturer guidelines. After synthesis, syringes with (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid were stored for 15, 30, 60, and 120 min. We evaluated Luer Lock syringes manufactured by different brands such as Artsana, Henke-Sass-Wolf, B. Braun Medical N.V., CODAN Medizinische Geräte GmbH & Co KG, Becton Dickinson and Company, and Terumo Europe. Adsorption of (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid was acceptably low for all syringes (<13%), except for two brands with (99m)Tc-DMSA(III) adsorption rates of 36 and 30%, respectively, and for one brand with a (99m)Tc-nanocolloid adsorption rate of 27%. Adsorption of (99m)Tc-DMSA(III) and (99m)Tc-nanocolloid reaches critical levels in syringes produced by two brands, potentially causing poor image quality--for example, in DMSA scans using pediatric radiopharmaceutical doses. It is advised to check the compatibility of any radiopharmaceutical with syringes as an integral part of the quality assurance program. PMID:24569706

Bauwens, Matthias; Pooters, Ivo; van der Pol, Jochen; Mottaghy, Felix M; van Kroonenburgh, Marinus

2014-04-01

87

Biodistribution of 99mTc Tricarbonyl Glycine Oligomers  

PubMed Central

99mTc tricarbonyl glycine monomers, trimers, and pentamers were synthesized and evaluated for their radiolabeling and in vivo distribution characteristics. We synthesized a 99mTc-tricarbonyl precursor with a low oxidation state (I). 99mTc(CO)3(H2O)3 + was then made to react with monomeric and oligomeric glycine for the development of bifunctional chelating sequences for biomolecules. Labeling yields of 99mTc-tricarbonyl glycine monomers and oligomers were checked by high-performance liquid chromatography. The labeling yields of 99mTc-tricarbonyl glycine and glycine oligomers were more than 95%. We evaluated the characteristics of 99mTc-tricarbonyl glycine oligomers by carrying out a lipophilicity test and an imaging study. The octanol-water partition coefficient of 99mTc tricarbonyl glycine oligomers indicated hydrophilic properties. Single-photon emission computed tomography imaging of 99mTc-tricarbonyl glycine oligomers showed rapid renal excretion through the kidneys with a low uptake in the liver, especially of 99mTc tricarbonyl triglycine. Furthermore, we verified that the addition of triglycine to prototype biomolecules (AGRGDS and RRPYIL) results in the improvement of radiolabeling yield. From these results, we conclude that triglycine has good characteristics for use as a bifunctional chelating sequence for a 99mTc-tricarbonyl- based biomolecular imaging probe.

Jang, Beom-Su; Lee, Joo-Sang; Rho, Jong Kook

2012-01-01

88

Development of more efficacious Tc-99m organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures. Progress report, May 1, 1982-April 30, 1983  

SciTech Connect

A procedure based on high performance liquid chromatography (HPLC) has been developed for separating individual Tc-diphosphonate complexes in skeletal-imaging radiopharmaceuticals prepared by reduction of TcO/sub 4//sup -/ with NaBH/sub 4/ in the presence of methylene diphosphonate (MDP). Seven different Tc-MDP complexes have been detected and isolated in pure form. Significant differences in skeletal uptake and blood clearance are exhibited by the three complexes tested thus far by biodistribution studies in test animals. The relative quantities of these complexes present in a radiopharmaceutical preparation are dramatically influenced by the pH of the reaction mixture. Thus, control of pH is a simple means of forming in high yield the single, most efficacious Tc-MDP complex for skeletal imaginG. An HPLC method with electrochemical detection has been developed for the analytical determination of total TcO/sub 4//sup -/ (/sup 99m/Tc + /sup 99/Tc). Concentrations of TcO/sub 4//sup -/ as low as 9 x 10/sup -9/ M can be detected. The method is being evaluated for monitoring total TcO/sub 4//sup -/ in /sup 99/Mo//sup 99m/Tc generators.

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

1982-11-01

89

New bone-seeking agent: Animal study of Tc99m-incadronate  

Microsoft Academic Search

Objective: Disodium cycloheptylaminomethylenediphosphonate monohydrate (incadronate disodium) is a third-generation bisphosphonate\\u000a compound which potently inhibits bone resorption, and a highly effective drug in the treatment of metastatic bone disease.\\u000a We first labeled incadronate disodium with99Tc, and examined its biodistribution and bone uptake after intravenous injection in rats to assess its potential for clinical\\u000a use as a bone-seeking agent for judgment of

Makoto Shigematsu; Susumu Shiomi; Hiroshi Iwao; Hironobu Ochi

2002-01-01

90

Pharmacokinetics of the phosphatidylserine tracers 99mTc-lactadherin and 99mTc-annexin V in pigs  

PubMed Central

Background Phosphatidylserine (PS) is a phospholipid normally located in the inner leaflet of the cell membrane. PS is translocated from the inner to the outer leaflet of the plasma membrane during the early stages of apoptosis and in necrosis. In cell and animal studies, reversible PS externalisation to the outer membrane leaflet has been observed in viable cells. Hence, PS markers have been proposed as markers of both reversibly and irreversibly damaged cells. The purpose of this experimental study in pigs was to investigate the kinetics of the newly introduced PS marker technetium-99m-labelled lactadherin (99mTc-lactadherin) in comparison with the well-known PS tracer 99mTc-annexin V with special reference to the renal handling of the tracers. The effective dose for humans was estimated from the biodistribution in 24 mice. Methods Nine anaesthetised pigs randomly allocated into two treatment groups were administered a single injection of either 99mTc-lactadherin or 99mTc-annexin V. Renal perfusion was assessed by simultaneous injection of 51Cr-EDTA. Throughout the examinations, planar, dynamic scintigraphy of the trunk was performed, urine was collected and arterial and renal vein blood was sampled. The effective dose was estimated using the adult male phantom from the RADAR website. Results 99mTc-lactadherin was cleared four times faster from plasma than 99mTc-annexin V, 57?±?13 ml/min (mean?±?SD) versus 14?±?2 ml/min. 99mTc-lactadherin had a predominant uptake in the liver, whereas 99mTc-annexin V was primarily taken up by the kidneys. The estimated effective human dose after single injection of 99mTc-lactadherin and 99mTc-annexin V was 5.8 and 11 ?Sv/MBq, respectively. Conclusions The high hepatic uptake of 99mTc-lactadherin compromises the use of 99mTc-lactadherin for imaging PS externalisation in the liver. Due to scatter from the liver, the use of in vivo visualisation of PS externalisation in the lower thorax and upper abdomen by 99mTc-lactadherin is challenged, but not precluded. In contrast to 99mTc-annexin, 99mTc-lactadherin has a low renal uptake and may be the preferred tracer for imaging PS externalisation in the kidneys. The effective dose after injection of 99mTc-lactadherin and 99mTc-annexin was low. Recommendations regarding the clinical use of 99mTc-lactadherin must await tracer kinetic studies in patients.

2013-01-01

91

[Research of 99mTcO4- and 99mTcO2- in injectable solutions of 99mTc-HMDP by inverse phase HPTLC].  

PubMed

Bone scintigraphy allows the diagnostic of many pathologies related to bone through the intravenous administration of a phosphonate bone marker complexed to 99 metastable technetium (99mTc). The instability of these injectable solutions on contact with air can lead to a mixture of pertechnetate VII (99mTcO4-) and technetium IV (99mTcO2-, xH2O), technetium IV being the only derivative to fix bone. A qualitative control of the purity of these solutions proved to be consequently important before administration. We report here the perfecting of a new chromatographic test based on reverse phase high performance thin layer chromatography (HPTLC). This test, simple, rapid and reproductive allows without ambiguity the detection of 99mTcO4-(VII) and 99mTcO2-(IV), xH2O in hydroxymethylene diphosphonate (HMDP) injectable solutions ready to use. PMID:16449940

Jacquot, Y; Zoubir, Br; Xicluna, A; Bidet, A-Cl

2006-01-01

92

A Meteorological Overview of the TC4 Mission  

NASA Technical Reports Server (NTRS)

The TC4 mission in Central America during summer 2007 examined convective transport into the tropical Upper Troposphere/Lower Stratosphere (UTLS) and the evolution of cirrus clouds. The tropical tropopause layer (TTL) circulation is dominated by the Asian monsoon anticyclone and westward winds that stretch from the western Pacific into the Atlantic. During TC4, TTL westward flow over Central America was stronger than normal. Incidence of cold clouds over the Central American region was the third lowest out of 34 years sampled. The major factor was an incipient La Nina, specifically anomalously cold temperatures off the Pacific Coast of South America. Weakness in the low level Caribbean jet caused a shift in the coldest clouds from the Caribbean to the Pacific side of Central America. The character of tropopause temperature variability was that of upward propagating waves generated by local and nonlocal convection. These waves produced tropopause temperature variations of 3 K, with peak-to-peak variations of 8 K. At low levels in Central America, flow from the Sahara desert predominated; further south, the air came from the Amazon region. Convectively influenced air in the upper troposphere came from Central America, the northern Amazon region, the Atlantic ITCZ, and the North American monsoon. In the TTL, Asian and African convection affected the observed air masses. North of 10N in the Central American TTL, African and Asian convection may have contributed as much to the air masses as Central and South American convection. South of 8N, Asian and African convection had far less impact.

Pfister, L.; Selkirk, H. B.; Starr, D. O.; Rosenlof, K.; Newman, P. F.

2010-01-01

93

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

94

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

95

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

96

High Tc SQUID Detector for Magnetic Metallic Particles in Products  

Microsoft Academic Search

High-Tc superconducting quantum interference device (SQUID) is an ultra-sensitive magnetic sensor. After the discovery of the high-Tc superconducting materials, the performance of the high-Tc SQUID has been improved and stabilized. One strong candidate for application is a detection system of magnetic foreign matters in industrial products. There is a possibility that ultra-small metallic foreign matter has been accidentally mixed with

Saburo Tanaka; Tomonori Akai; Yoshimi Hatsukade; Shuichi Suzuki

2009-01-01

97

Coordination of pertechnetate [TcO4]- to actinides.  

PubMed

The ability of [TcO(4)](-) to coordinate directly to tetra- and hexa-valent actinides in the presence of organic P[double bond, length as m-dash]O ligands is confirmed in the crystallographically characterised complexes [UO(2)(TcO(4))(2)(Ph(3)PO)(3)] and [Th(TcO(4))(4)((n)Bu(3)PO)(4)]. PMID:15490000

Sarsfield, Mark J; Sutton, Andrew D; May, Iain; John, Gordon H; Sharrad, Clint; Helliwell, Madeleine

2004-10-21

98

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

99

Radioactive equilibrium: 99Mo/99mTc decay characteristics.  

PubMed

Within the Decay Data Evaluation Project, as an example of a radioactive equilibrium with isomer, the (99)Mo/(99m)Tc equilibrium mixture decay characteristics are examined. The results of a new decay data evaluation are presented for (99)Mo/(99m)Tc decay to nuclear levels in (99)Tc. These evaluated data have been obtained using information published up to 2013. PMID:24309009

Chechev, Valery P; Bé, Marie-Martine

2014-05-01

100

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

101

High-Tc superconductors in the two-dimensional limit:  

PubMed

The free modulation of interlayer distance in a layered high-transition temperature (high-Tc) superconductor is of crucial importance not only for the study of the superconducting mechanism but also for the practical application of high-Tc superconducting materials. Two-dimensional (2D) superconductors were achieved by intercalating a long-chain organic compound into bismuth-based high-Tc cuprates. Although the intercalation of the organic chain increased the interlayer distance remarkably, to tens of angstroms, the superconducting transition temperature of the intercalate was nearly the same as that of the pristine material, suggesting the 2D nature of the high-Tc superconductivity. PMID:9616119

Choy; Kwon; Park

1998-06-01

102

ND4L gene concurrent 10609T>C and 10663T>C mutations are associated with Leber's hereditary optic neuropathy in a large pedigree from Kuwait  

PubMed Central

Background Leber's hereditary optic neuropathy (LHON) is a condition characterised by a rapid bilateral central vision loss due to death of the retinal ganglion cells, leading to visual impairment commonly occurring during young adulthood. The disease manifests itself more in male patients than female patients. The mtDNA mutations m.11778G>A, m.3460G>A and m.14484T>C are by far more frequent in LHON than any other mutation. In this report, a multi-generational Arab family from Kuwait with 14 male members with LHON was investigated. Methods Complete mtDNA mutational analysis by direct Sanger's sequencing was carried out to detect pathogenic mutations, polymorphisms and haplogrouping. Results All maternally related subjects from this study who were examined expressed the L3 haplotype background, with two concurrent mtDNA mutations, 10609T>C and 10663T>C, that led to non-conservative amino acid changes of Ile47Thr and Val65Ala, respectively. The two variations were absent in 144 normal and ethnicity-matched controls. Conclusions The two identified mutations associated with LHON in this family may exert their pathogenicity through a cumulative or haplogroup effect. This is the first report of the presence of two concurrent mutations in the ND4L gene in individuals with LHON who carry the L3 haplogroup.

Behbehani, Raed; Melhem, Motasem; Alghanim, Ghazi; Behbehani, Kazem; Alsmadi, Osama

2014-01-01

103

Antisocial personality disorder and TC treatment outcomes.  

PubMed

There is a belief that persons diagnosed with antisocial personality disorder (APD) do not respond well to treatment, but the existing research has not supported this hypothesis. This study examined the relationship of APD to therapeutic community (TC) treatment outcomes. A total of 275 men and women were randomly assigned to two TCs. It was hypothesized that clients diagnosed with APD via the Millon Clinical Multiaxial Inventory (MCMI-II) would have poorer treatment outcomes than those with no APD. The MCMI-II was used to diagnose APD because of its focus in underlying pathological personality traits, as opposed to strict behavioral criteria as used in the Diagnostic and Statistical Manual of Mental Disorders classifications for APD; this hypothesis was not supported. Logistic regression analyses indicated that an MCMI-II diagnosis of APD was unrelated to treatment outcomes. Treatment completion was the most important factor in reducing recent drug use and post-discharge arrests. The results indicate that persons diagnosed with APD, with histories of substantial drug abuse and criminality, can benefit from TC treatment with aftercare in the community or at the very least, do as well as those with no APD. In light of the high prevalence rates of APD in substance-abusing populations, future research should continue to explore the many issues surrounding the diagnosis of APD, as well as its relationship to treatment outcomes. PMID:12014812

Messina, Nena P; Wish, Eric D; Hoffman, Jeffrey A; Nemes, Susanna

2002-01-01

104

High-Tc superconducting quantum interference device recordings of spontaneous brain activity: Towards high-Tc magnetoencephalography  

NASA Astrophysics Data System (ADS)

We have performed single- and two-channel high transition temperature (high-Tc) superconducting quantum interference device (SQUID) magnetoencephalography (MEG) recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of two well-known brain rhythms: the occipital alpha rhythm and the mu rhythm found in the motor cortex. We further show that despite higher noise-levels compared to their low-Tc counterparts, high-Tc SQUIDs can be used to detect and record physiologically relevant brain rhythms with comparable signal-to-noise ratios. These results indicate the utility of high-Tc technology in MEG recordings of a broader range of brain activity.

Öisjöen, F.; Schneiderman, J. F.; Figueras, G. A.; Chukharkin, M. L.; Kalabukhov, A.; Hedström, A.; Elam, M.; Winkler, D.

2012-03-01

105

Production of the charged top-pions from TC2 model at the TeV energy e-? colliders  

NASA Astrophysics Data System (ADS)

The top-pions (?t 0,±) and the top-Higgs (ht 0) are the typical particles predicted by the topcolor-assisted technicolor (TC2) model and the observation of these particles can be regarded as direct evidence of the TC2 model. In this paper, we study three pair production processes of these new particles at the next generation e? colliders, i.e., e-??e-?t +?t -, e-???e?t -?t 0 and e-???e?t -ht 0. The results show that the production rates can reach the level 100-101 fb with reasonable parameter values. So one can expect that enough signals could be produced in future high- energy linear collider experiments. Furthermore, the flavor-changing (FC) decay modes ?t -?bc¯, ?t 0(ht 0)?tc¯ can provide us with the typical signal to detect these new particles.

Liu, Yao-Bei; Wang, Xue-Lei

2008-01-01

106

A Tc-99m labeled laminin derived peptide, Tc-99m-YIGSR for thrombus specific imaging  

SciTech Connect

Laminin derived adhesive peptides were studied as potential agents for thrombus specific imaging. Using a novel peptide Tc-99m labeling method studies were performed in vitro using human whole blood clots and platelets, and in vivo scintigraphy in animals with experimental thrombi. Aliquots of 0.1 ml human blood were placed in inclined Petri dishes until clot was well formed. Clots were rinsed 3x with phosphate buffer and 10 {mu}Ci Tc-99m YIGSR II was added. After incubation at room temperature for 1 hr, clots were again washed 3x. Residual activity was measured. Platelets were harvested using routine methods and incubated with Tc-99m YIGSR II, washed and assayed. Blocking experiments using cold YIGSR II showed that the Tc-99m labeled peptide preparation YIGSR II binds specifically and selectively to clot and platelets as compared to control experiments using nonspecific human Tc-99m IgG. Tissue distribution studies showed rapid blood clearance, urinary excretion and to a lesser degree GI tract excretion. Tc-99m YIGSR II was lower in all organs except kidneys compared to Tc-99m 50 H.19, Tc-99m IgG and Tc-99m YIGSR I. Tc-99m-YIGSR II consistently visualized thrombi within 30 min p.i. In vivo scintigraphic (thrombus/contralateral side) ratio was 3:1 and ex vivo direct counting (thrombosed to nonthrombosed vessel segment) was 5.4: 1. Compared to monoclonal antibodies peptide preparations are non- or minimally immunogenic, preparation is probably less expensive and there is also less danger of viral DNA contamination. These considerations and our data indicate that the Tc-99m-YIGSR II peptide has significant potential as a thrombus imaging agent.

Wang, G.J.; Oster, Z.H.; Som, P. [Brookhaven National Lab., Upton, NY (United States)] [and others

1994-05-01

107

Electron tunneling in high Tc superconductors  

SciTech Connect

Tunneling observations of the linear background have helped establish the participation of the high Tc superconductors BaPb(0.75)Bi(0.25)O3 and Ba(1-x)K(x)BiO3 in the class of cuprate superconductors. This linear behavior calls into question whether the materials can be thought of as Fermi liquids, or whether correlation effects are sufficiently strong to dominate the observed behavior. These Ba-Bi compositions have yielded energy gap values in electron tunneling experiments which are close to the BCS theory values; the shape of the excitation spectrum fits the BCS model especially well. By contrast, BCS behavior has not yet been convincingly observed in the cuprates. 28 refs.

Valles, J.M. Jr.; Dynes, R.C. (Oregon Univ., Eugene (USA) AT T Bell Laboratories, Murray Hill, NJ (USA))

1990-06-01

108

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

109

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

110

Gauge bosons masses in a SU(2){sub TC} x SU(3){sub L} x U(1){sub X} extension of the standard model  

SciTech Connect

In this brief report we explore the full realization of the dynamical symmetry breaking of an 3-3-1 model to U(1){sub em} considering a model based on SU(2){sub TC} x SU(3){sub L} x U(1){sub X}. We compute the mass generated for the charged and neutral gauge bosons of the model that result from the symmetry breaking, and verify the equivalence between a 3-3-1 model with a scalar content formed by the set of the fundamental scalar bosons {chi},{rho} and {eta} with a 3-3-1 model where the dynamical symmetry breaking is implanted by the system formed by the set of composite bosons {Phi}{sub T},{Phi}{sub TC(1)} and {Phi}{sub TC(2)}. In this model the minimal composite scalar content is fixed by the condition of the cancellation of triangular anomaly in the technicolor (TC) sector.

Doff, A. [Universidade Tecnologica Federal do Parana-UTFPR-COMAT, Via do Conhecimento Km 01, 85503-390, Pato Branco, PR (Brazil)

2010-06-01

111

SH3TC2/KIAA1985 protein is required for proper myelination and the integrity of the node of Ranvier in the peripheral nervous system  

PubMed Central

Charcot–Marie–Tooth disease type 4C (CMT4C) is an early-onset, autosomal recessive form of demyelinating neuropathy. The clinical manifestations include progressive scoliosis, delayed age of walking, muscular atrophy, distal weakness, and reduced nerve conduction velocity. The gene mutated in CMT4C disease, SH3TC2/KIAA1985, was recently identified; however, the function of the protein it encodes remains unknown. We have generated knockout mice where the first exon of the Sh3tc2 gene is replaced with an enhanced GFP cassette. The Sh3tc2?Ex1/?Ex1 knockout animals develop progressive peripheral neuropathy manifested by decreased motor and sensory nerve conduction velocity and hypomyelination. We show that Sh3tc2 is specifically expressed in Schwann cells and localizes to the plasma membrane and to the perinuclear endocytic recycling compartment, concordant with its possible function in myelination and/or in regions of axoglial interactions. Concomitantly, transcriptional profiling performed on the endoneurial compartment of peripheral nerves isolated from control and Sh3tc2?Ex1/?Ex1 animals uncovered changes in transcripts encoding genes involved in myelination and cell adhesion. Finally, detailed analyses of the structures composed of compact and noncompact myelin in the peripheral nerve of Sh3tc2?Ex1/?Ex1 animals revealed abnormal organization of the node of Ranvier, a phenotype that we confirmed in CMT4C patient nerve biopsies. The generated Sh3tc2 knockout mice thus present a reliable model of CMT4C neuropathy that was instrumental in establishing a role for Sh3tc2 in myelination and in the integrity of the node of Ranvier, a morphological phenotype that can be used as an additional CMT4C diagnostic marker.

Arnaud, Estelle; Zenker, Jennifer; de Preux Charles, Anne-Sophie; Stendel, Claudia; Roos, Andreas; Medard, Jean-Jacques; Tricaud, Nicolas; Kleine, Henning; Luscher, Bernhard; Weis, Joachim; Suter, Ueli; Senderek, Jan; Chrast, Roman

2009-01-01

112

Power Systems Development Facility Gasification Test Campaign TC20  

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 the Transport Gasifier following significant modifications of the gasifier configuration. This demonstration took place during test campaign TC20, occurring from August 8 to September 23, 2006. The modifications proved successful in increasing gasifier residence time and particulate collection efficiency, two parameters critical in broadening of the fuel operating envelope and advancing gasification technology. The gasification process operated for over 870 hours, providing the opportunity for additional testing of various gasification technologies, such as PCD failsafe evaluation and sensor development.

Southern Company Services

2006-09-30

113

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

114

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

115

Tc1-like transposable elements in plant genomes  

PubMed Central

Background The Tc1/mariner superfamily of transposable elements (TEs) is widespread in animal genomes. Mariner-like elements, which bear a DDD triad catalytic motif, have been identified in a wide range of flowering plant species. However, as the founding member of the superfamily, Tc1-like elements that bear a DD34E triad catalytic motif are only known to unikonts (animals, fungi, and Entamoeba). Results Here we report the identification of Tc1-like elements (TLEs) in plant genomes. These elements bear the four terminal nucleotides and the characteristic DD34E triad motif of Tc1 element. The two TLE families (PpTc1, PpTc2) identified in the moss (Physcomitrella patens) genome contain highly similar copies. Multiple copies of PpTc1 are actively transcribed and the transcripts encode intact full length transposase coding sequences. TLEs are also found in angiosperm genome sequence databases of rice (Oryza sativa), dwarf birch (Betula nana), cabbage (Brassica rapa), hemp (Cannabis sativa), barley (Hordium valgare), lettuce (Lactuta sativa), poplar (Populus trichocarpa), pear (Pyrus x bretschneideri), and wheat (Triticum urartu). Conclusions This study extends the occurrence of TLEs to the plant phylum. The elements in the moss genome have amplified recently and may still be capable of transposition. The TLEs are also present in angiosperm genomes, but apparently much less abundant than in moss.

2014-01-01

116

Interactions of Tc(IV) with humic substances.  

PubMed

To understand the key processes affecting 99Tc mobility in the subsurface and help with the remediation of contaminated sites, the binding constants of several humic substances (humic and fulvic acids) with Tc(IV) were determined, using a solvent extraction technique. The novelty of this paper lies in the determination of the binding constants of the complexes formed with the individual species TcO(OH)+ and TcO(OH)2(0). Binding constants were found to be 6.8 and between 3.9 and 4.3, for log?1,-1,1 and log?1,-2,1, respectively; these values were little modified by a change of ionic strength, in most cases, between 0.1 and 1.0 M, nor were they by the nature and origin of the humic substances. Modeling calculations based on these show TcO(OH)-HA to be the predominant complex in a system containing 20 ppm HA and in the 4-6 pH range, whereas TcO(OH)2(0) and TcO(OH)2-HA are the major species, in the pH 6-8 range. PMID:21366306

Boggs, Mark A; Minton, Travis; Dong, Wenming; Lomasney, Samuel; Islam, Mohammed R; Gu, Baohua; Wall, Nathalie A

2011-04-01

117

High Tc superconducting levitation motor with a laser commutator  

NASA Astrophysics Data System (ADS)

A high Tc superconducting levitation bearing driven by an optically switched solenoid is described. The bearing uses flux pinning in the new high Tc superconductors for stability. A simple liquid nitrogen supply system is described that greatly improves the ease with which high Tc superconductors can be maintained at 77 K for extended periods of time in small styrofoam dishes. A force versus height curve is given and is used to determine the design limits of the levitation bearing. Alternate motor designs are discussed.

Weeks, David E.

1990-01-01

118

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

119

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.

120

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

121

Theory of superconducting Tc of doped fullerenes  

NASA Astrophysics Data System (ADS)

We develop the nonadiabatic polaron theory of superconductivity of MxC60 taking into account the polaron band narrowing and realistic electron-phonon and Coulomb interactions. We argue that the crossover from the BCS weak-coupling superconductivity to the strong-coupling polaronic and bipolaronic superconductivity occurs at the BCS coupling constant ?~1 independent of the adiabatic ratio, and there is nothing ``beyond'' Migdal's theorem except small polarons for any realistic electron-phonon interaction. By the use of the polaronic-type function and the ``exact'' diagonalization in the truncated Hilbert space of vibrons (``phonons'') we calculate the ground-state energy and the electron spectral density of the C-60 molecule. This allows us to describe the photoemission spectrum of C-60 in a wide energy region and determine the electron-phonon interaction. The strongest coupling is found with the high-frequency pinch Ag(2) mode and with the Frenkel exciton. We clarify the crucial role of high-frequency bosonic excitations in doped fullerenes which reduce the bare bandwidth and the Coulomb repulsion allowing the intermediate- and low-frequency phonons couple two small polarons in a Cooper pair. The Eliashberg-type equations are solved for low-frequency phonons. The value of the superconducting Tc, its pressure dependence and the isotope effect are found in remarkable agreement with the available experimental data.

Alexandrov, A. S.; Kabanov, V. V.

1996-08-01

122

Research on high Tc superconducting compounds  

NASA Technical Reports Server (NTRS)

Mossbauer research using the 21.54 kev resonance radiation of Eu-151 on the high temperature superconductors Bi(2)Ca(0.5)Eu(0.5)Sr(2)CU2O(x), and EuBa(2)CU(3)O(7-x) is performed. For the Bismuth compound the Mossbauer measurements gave a weak signal at room temperature but improved at lower temperatures. Experimental data indicated that europium is located at only one crystallographic site. Isomer shift measurements were .69 + 0.02 mm/s with respect to EuF(3). The linewidth at room temperature was found to be 2.54 mm/s. This value falls within the values observed by other researchers on Eu based 1,2,3 high-Tc compounds. Our results also show the Eu to be trivalent with no trace of divalent europium present. Superconducting europium based 1,2,3 compounds were prepared and measurements completed. Our results show the Eu to be trivalent with no trace of divalent europium present. These compounds had an average isomer shift of .73 mm/s +/- O.02 for all samples made. One of these was irradiated with 3.5 X 10(exp 16) neutrons and a comparison made of the Mossbauer parameters for the irradiated and non-irradiated samples. Experimental results showed no difference between linewidths but a measurable effect was seen for the isomer shift.

Oliver, Frederick W. (Principal Investigator)

1996-01-01

123

High Tc thin film and device development  

NASA Astrophysics Data System (ADS)

Thin films of the high-Tc superconductor YBa2Cu3O(y) have been deposited on various substrates by diode and magnetron sputtering using bulk sintered targets. These films have been analyzed by a variety of methods: scanning electron microscopy, X-rays, electron beam microprobe, mass spectrometry and Raman spectroscopy. The stoichiometries of the films have been measured as a function of the radial position from the center of the sputtered beam at a fixed target-substrate distance. Patterning of the films has been carried out to form planar structures such as strip lines, microbridges and RF SQUIDs (superconducting quantum interference devices). The DC current-voltage characteristics of the microbridges were measured as a function of temperature. RF SQUID behavior has been observed for single-loop devices and their properties established at 4.2 K and higher temperatures. Flux-locked noise spectra with a 1/f noise power response were recorded in the frequency range from 0.01 to about 100 Hz. RF SQUID signals have been observed for temperatures up to 55 K.

Betts, K.; Burbank, M. B.; Cragg, A.; Fife, A. A.; Kubik, P. R.

1989-03-01

124

Josephson tunneling in high-{Tc} superconductors  

SciTech Connect

Investigation of the overlap of the pair wavefunction of a conventional superconductor with that of a high {Tc} cuprate should reveal the symmetry of the superconducting order parameter of the cuprate. The authors have been studying this overlap by Josephson tunneling (tunneling as opposed to SNS or weak link) between conventional superconductors (Pb, Sn) and YBCO. The observation of Josephson coupling in the c direction implies that the order parameter in YBCO is not strictly of d{sub x2{minus}y2} symmetry. They have carried out studies on YBCO in the form of twinned and detwinned single crystals and thin films on various substrates. The magnetic field dependence of the Josephson current I{sub c}(B) allows a direct, d.c., and low field measurement of the low temperature penetration depth {lambda}{sub ab}. Measurements of {lambda}{sub a} and {lambda}{sub b} in detwinned single crystals of YBCO give the value of in-plane anisotropy ratio in this material.

Sun, A.G.; Katz, A.S.; Truscott, A.; Dynes, R.C.; Gajewski, D.A.; Han, S.H.; Maple, M.B. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Physics; Veal, B.W.; Gu, C. [Argonne National Lab., IL (United States). Materials Science Div.

1996-05-01

125

Development and applications of high Tc superconducting bulk materials  

Microsoft Academic Search

This paper summarizes the high Tc superconducting (HTS) bulk materials, with regard to material preparations, characteristics, and practical applications. Consequently it provides the technical base for practical development and applications of the HTS bulk materials to devices.

Z. Z. Hu; J. X. Jin; J. Liu; H. T. Ren; L. H. Lei; T. F. Xiang

2009-01-01

126

Radiopharmaceutical evaluation of Tc-99m hydroxymethylene diphosphonate  

SciTech Connect

The radiopharmaceutical purity and stability of Tc-99m hydroxymethylene diphosphonate were studied over a ten-week period using miniaturized chromatography to evaluate levels of both free pertechnetate and hydrolyzed reduced Tc-99m. Results showed good preparation stability up to 4hr postformulation even when 400 mCi of activity was added. After 4 hr postformulation, some inconsistent radiopharmaceutical degradation was observed. Both old and new formulations of Tc-99m hydroxymethylene diphosphonate were very sensitive to air introduction. The new formulation was less sensitive to air oxidation because of higher stannous chloride and gentisic acid levels. We stress careful technique when dispensing Tc-99m hydroxymethylene diphosphonate in order to minimize any air introduction.

Majewski, W.; Zimmer, A.M.; Spies, S.M.

1983-03-01

127

Separation of tc from Uranium and development of metallic Technetium waste forms  

NASA Astrophysics Data System (ADS)

The isotope Technetium-99 (99Tc) is a major fission product of the nuclear industry. In the last decade, approximately 20 tons of 99Tc have been produced by the US nuclear industry. Due to its long half-life (t1/2 = 214,000 yr), beta radiotoxicity, and high mobility as pertechnetate [TcO4]-, Tc represents long-term concern to the biosphere. Various options have been considered to manage 99Tc. One of them is its separation from spent fuel, conversion to the metal and incorporation into a metallic waste form for long-term disposal. After dissolution of spent fuel in nitric acid and extraction of U and Tc in organic media, previously developed methods can be used to separate Tc from U, convert the separate Tc stream to the metal and reuse the uranium component of the fuel. A variety of metallic waste forms, ranging from pure Tc metal to ternary Tc alloys combined with stainless steel (SS) and Zr are proposed. The goal of this work was to examine three major questions: What is the optimal method to separate Tc from U? After separation, what is the most efficient method to convert the Tc stream to Tc metal? Finally, what is the corrosion behavior of Tc metal, Tc-SS alloys and Tc-Zr-SS alloys in 0.01M NaCl? The goal is to predict the long term behavior of Tc metallic waste in a hypothetical storage environment. In this work, three methods have been used to separate Tc from U: anionic exchange resin, liquid-liquid extraction and precipitation. Of the three methods studied, anionic exchange resins is the most selective. After separation of Tc from U, three different methods were studied to convert the Tc stream to the metal: thermal treatment under hydrogen atmosphere, electrochemical and chemical reduction of pertechnetate in aqueous media. The thermal treatment of the Tc stream under hydrogen atmosphere is the preferred method to produce Tc metal. After Tc metal is isolated, it will be incorporated into a metal host phase. Three different waste forms were produced for corrosion studies in this work: Pure Tc metal, SS(Tc 2 wt%)Zr and SS(Tc 1.34 wt%) alloys. Corrosion rate measurements indicate that both SS(Tc 2 wt%)Zr and SS(Tc 1.34 wt%) alloys corrode more slowly than metallic Tc in the solutions tested.

Mausolf, Edward John

128

Solvent Extraction of Tc and Cs from Alkaline Nitrate Wastes  

SciTech Connect

This paper summarizes progress at three collaborating US national laboratories on the extraction of the fission products {sup 99}Tc and {sup 137}Cs from alkaline high-level wastes (HLW). 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 countercurrent centrifugal-contactor tests on simulants.

Bonnesen, P.V.; Conner, C.; Delmau, L.H.; Haverlock, T.J.; Leonard, R.A.; Lumetta, G.J.; Moyer, B.A.; Sachleben, R.A.

1999-07-11

129

trans-K3[TcO2(CN)4  

Microsoft Academic Search

The dioxotetracyanotechnetate anion, [TcO2(CN)4]3-, of the title complex has octahedral symmetry. The technetium is located on a center of inversion and is bound by two oxygen atoms and four cyano ligands. The TcO bond distance of 1.7721 (12) Å is consistent with double bond character. The potassium cations [located on special (1\\/2,0,1) and general positions] reside in octahedral or tetrahedral

Sayandev Chatterjee; Andrew S. Del Negro; Matthew K. Edwards; Brendan Twamley; Jeanette A. Krause; Samuel A. Bryan

2010-01-01

130

The LIMSI 2006 TC-STAR EPPS Transcription Systems  

Microsoft Academic Search

This paper describes the speech recognizers developed to transcribe European Parliament Plenary Sessions (EPPS) in English and Spanish in the 2nd TC-STAR Evaluation Campaign. The speech recognizers are state-of-the-art systems using multiple decoding passes with models (lexicon, acoustic models, language models) trained for the different transcription tasks. Compared to the LIMSI TC-STAR 2005 EPPS systems, relative word error rate reductions

L. Lamel; J.-L. Gauvain; G. Adda; C. Barras; E. Bilinski; O. Galibert; A. Pujol; H. Schwenk; Xuan Zhu

2007-01-01

131

High-Tc cuprate superconductivity in a nutshell  

NASA Astrophysics Data System (ADS)

Since the discovery of high-Tc cuprate superconductivity in 1986 many new experimental techniques and theoretical concepts have been developed. In particular it was shown that the BCS theory of d-wave superconductivity describes semi-quantitatively the high-Tc superconductivity. Furthermore, it was demonstrated that Volovik's approach is extremely useful for finding the quasiparticle properties in the vortex state. Here we survey these developments and forecast future directions.

Won, Hyekyung; Haas, Stephan; Parker, David; Maki, Kazumi

2005-02-01

132

An Economical Magnetocardiogram System Based on High-Tc SQUIDs  

Microsoft Academic Search

An economical magnetocardiogram (MCG) system is built in our laboratory. It mainly consists of a MCG data acquisition stage equipped with two high-Tc superconducting quantum interference device (SQUID) magnetometers, a data processing stage with digital filtering and a one-layer mu-metal magnetically shielded room in conjunction with a high-Tc SQUID based active compensation. Experimental results show that a noise level of

Zhuo Li; Xue-Min Zhu; Li-Hua Zhang; Xu-Guang Huang; Yu-Feng Ren; Geng-Hua Chen; Qian-Sheng Yang; Ji Feng

2006-01-01

133

Characteristics of Tc99m-complexes of large tetraphosphonates  

Microsoft Academic Search

Tetraphoshonate derivates of dicyclopentadiene (TPDCPD), norbornane (TPNB) and piperazine (TPP) inhibit boiler scale by forming stable ''C-clamp'' chelate structures with calcium and other metals. Their large size and molecular composition of several phosphate groups should favor the formation of Tc-99m chelates with greater chemical purity than the Tc-99m diphosphonates used for clinical skeletal imaging. All three were evaluated and compared

W. A. Volkert; J. Simon; D. A. Wilson; B. Edwards; E. H. McKenzie; P. Oberle; R. A. Holmes

1984-01-01

134

MMTS, a new subfamily of Tc1-like transposons.  

PubMed

A novel Tc1-like transposable element has been identified as a new DNA transposon in the mud loach, Misgurnus mizolepis. The M. mizolepis Tc1-like transposon (MMTS) is comprised of inverted terminal repeats and a single gene that codes Tc1-like transposase. The deduced amino acid sequence of the transposase-encoding region of MMTS transposon contains motifs including DDE motif, which was previously recognized in other Tc1-like transposons. However, putative MMTS transposase has only 34-37% identity with well-known Tc1, PPTN, and S elements at the amino acid level. In dot-hybridization analysis used to measure the copy numbers of the MMTS transposon in genomes of the mud loach, it was shown that the MMTS transposon is present at about 3.36 x 104 copies per 2 x 109 bp, and accounts for approximately 0.027% of the mud loach genome. Here, we also describe novel MMTS-like transposons from the genomes of carp-like fishes, flatfish species, and cichlid fishes, which bear conserved inverted repeats flanking an apparently intact transposase gene. Additionally, BLAST searches and phylogenetic analysis indicated that MMTS-like transposons evolved uniquely in fishes, and comprise a new subfamily of Tc1-like transposons, with only modest similarity to Drosophila melanogaster (foldback element FB4, HB2, HB1), Xenopus laevis, Xenopus tropicalis, and Anopheles gambiae (Frisky). PMID:18612245

Ahn, Sang Jung; Kim, Moo-Sang; Jang, Jae Ho; Lim, Sang Uk; Lee, Hyung Ho

2008-10-31

135

Accumulation of 99Tc in duckweed Lemna minor L. as a function of growth rate and 99Tc concentration  

Microsoft Academic Search

This study focuses on the question of whether short-term studies can be used to forecast the accumulation of the long-lived fission product 99Tc in duckweed, Lemna minor L., grown in the field; in other words, are the accumulation parameters independent of changing growth rates typical of natural populations of duckweed. Two processes determine the 99Tc accumulation: (i) uptake and release

Jasper Hattink; Hubert Th. Wolterbeek

2001-01-01

136

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

137

Clinical comparison of diisopropyl-IDA Tc 99m and diethyl-IDA Tc 99m for evaluation of the hepatobiliary system  

SciTech Connect

Thirty-one patients with a wide range of hepatobiliary function and clinical diagnoses were studied with both diisopropyl-IDA Tc 99m and diethyl-IDA Tc 99m. Images were similar except for an increased liver-to-kidney ratio with diisopropyl-IDA Tc 99m and a tendency toward an increased liver-to-background ratio at five minutes with diisopropyl-IDA Tc 99m. Quantification of the relative hepatocyte extraction efficiency indicated a 16% higher extraction efficiency for diisopropyl-IDA Tc 99m. Both radiopharmaceuticals demonstrated increasing renal excretion with increasing total serum bilirubin levels; however, renal excretion of diisopropyl-IDA Tc 99m increased more slowly than excretion of diethyl-IDA Tc 99m. We conclude that, while the overall differences between these two radiopharmaceuticals are small, diisopropyl-IDA Tc 99m is superior because of a lower renal excretion rate in patients with decreased hepatocyte function.

Klingensmith, W.C. III; Fritzberg, A.R.; Spitzer, V.M.; Kuni, C.C.; Shanahan, W.S.M.

1981-09-01

138

ERROR CORRECTING CODES FOR THIRD GENERATION WIRELESS COMMUNICATION  

Microsoft Academic Search

Berreu et. al. in their landmark paper first introduced turbo codes (TC), which could achieve energy efficiencies within 0.7 dB of Shannon's limit. Now TC is one of the main options for error correcting codes (ECC) in third generation mobile standards as in UMTS (Universal Mobile Telecommunications System) and cdma2000. UMTS and cdma2000 standards use two types of ECC; Convolutional

Ashraf Uddin Bhuiyan; Shamsul Alam

139

Temperature dependence of a high-Tc single-flux-quantum logic gate up to 50 K  

Microsoft Academic Search

Basic characteristics of a simple single-flux-quantum (SFQ) logic gate using high-Tc material and Josephson junction (NdBa2Cu3O7-delta and focused ion beam junction) have been investigated. The logic gate consists of an rf-superconducting quantum interference device (rf-SQUID) and a dc-SQUID. In the logic gate, elementary SFQ logic operations, such as generating SFQ (dc\\/SFQ) and providing simultaneous readout (SFQ\\/dc), have been confirmed up

Kazuo Saitoh; Tadashi Utagawa; Youichi Enomoto

1998-01-01

140

A Th17-like developmental process leads to CD8(+) Tc17 cells with reduced cytotoxic activity.  

PubMed

Activation of naive CD8(+) T cells with antigen in the absence of skewing cytokines triggers their differentiation into effector CTL, which induces death of target cells. We show that CD8(+) T cells activated in the presence of the cytokines IL-6 or IL-21 plus TGF-beta similar to CD4(+) T cells, develop into IL-17-producing (Tc17) cells. These cells display greatly suppressed cytotoxic function along with low levels of the CTL markers: T-box transcription factor Eomesodermin, granzyme B and IFN-gamma. Instead, these cells express hallmark molecules of Th17 program including retinoic acid receptor-related orphan receptor (ROR)gammat, RORalpha, IL-21 and IL-23R. The expression of the type 17 master regulator RORgammat is causally linked to Tc17 generation, because its overexpression stimulates production of IL-17 in the presence of IL-6 or IL-21. Both, upregulation of the type 17 program as well as suppression of CTL differentiation are STAT3 dependent. Furthermore, Tc17 cells producing IL-17 but not granzyme B are also detectable in EAE, a mouse model for multiple sclerosis. Our data point to the existence of mutually exclusive CTL and Tc17 developmental pathways in vitro and in vivo. PMID:19544308

Huber, Magdalena; Heink, Sylvia; Grothe, Henrike; Guralnik, Anna; Reinhard, Katharina; Elflein, Karin; Hünig, Thomas; Mittrücker, Hans-Willi; Brüstle, Anne; Kamradt, Thomas; Lohoff, Michael

2009-07-01

141

Usage of radiopharmaceuticals in the development of pharmaceutical drug delivery systems: validation of [ 99mTc]DTPA and [ 99mTc]ECD  

Microsoft Academic Search

Tablets containing drugs of different lipophilicity, ranitidine and cinarizine, and placebo were prepared and their in vitro behaviour was studied by dissolution and disintegration tests. [99mTc]Diethylenetriamine-pentaacetic acid ([99mTc]DTPA) and [99mTc]ethyl cysteinate dimer ([99mTc]ECD) were used as tracers of the process. Both of them were added to tablets during wet granulation. Dissolution and disintegration profiles were assessed at different pH values

Mariella Terán; Eduardo Savio; Andrea Paolino; Malcolm Frier

2004-01-01

142

Trypanosoma cruzi discrete typing units (DTUs): Microsatellite loci and population genetics of DTUs TcV and TcI in Bolivia and Peru  

Microsoft Academic Search

Trypanosoma cruzi, the agent of Chagas disease, is usually subdivided into six discrete typing units (DTUs), TcI to TcVI, among which TcI and TcV are most common in human infections in Bolivia. Multilocus microsatellite typing (MLMT) was selected to further explore the structure of the natural populations belonging to these DTUs. The analysis showed that microsatellite clustering does not fully

Christian Barnabé; Thierry De Meeûs; François Noireau; Marie-France Bosseno; Eric Marcelo Monje; François Renaud; Simone Frédérique Brenière

2011-01-01

143

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

144

Vapreotide labeled with Tc-99m for imaging tumors.  

PubMed

Vapreotide (RC-160), an octapeptide analog of somatostatin, has a high affinity for somatostatin receptor subtypes SSTR2 and SSTR5. Vapreotide binds differently to the tumors of the breast, ovary, exocrine pancreas, prostate and colon, than octreotide another octapeptide analog of somatostatin. Vapreotide was labeled with Tc-99m, a radionuclide highly suitable for scintigraphic imaging. The labeling procedure was simple, produced >70% yields and could be applicable to label other peptides containing a cystine bridge. HPLC analysis showed that the tracer was stable when Tc-99m-RC-160 was challenged with 100 fold molar excess DTPA (diethylenetriaminepentaacetic acid), HSA (human serum albumin) or cysteine and incubated at 37 degrees C for 4 h. HPLC analysis of urine samples obtained from mice that received Tc-99m-RC-160 showed that the preparation was stable in vivo. Rat brain cortex membrane receptor displacement assays showed that the Kd values for Tc-99m-RC-160 (71x10(-9) M) and Tc-99m-octreotide (86x10(-9) M) (Sandostatin(R)) were in nM range, and were similar to that for I-125-RC-160 (46x10(-9) M). High binding affinity of Tc-99m-RC-160 for human breast tumor cells SKBR-3 was also observed. These results suggest that Tc-99m-RC-160 is worthy of evaluation as an agent for scintigraphic imaging of tumors rich in somatostatin receptor subtypes SSTR2 and SSTR5. PMID:21541533

Thakur, M; Kolan, H; Rifat, S; Li, J; Rux, A; John, E; Halmos, G; Schally, A

1996-09-01

145

Paper chromatographic and paper elettrophoretic study of the solution chemistry of Tc-99m-methylendiphosphonate and of Tc-99m-dimercaptosuccinate for improving the tumour-affinity of Tc-99m during scintigraphic imaging of cancer.  

PubMed

In order to find the conditions under which Tc-99m-methylenediphosphonate (Tc-99m-MDP) and Tc-99m(V)-dimercaptosuccinate (Tc-99m(V)-DMSA) may become tumour-seeking agents, leaving healthy organs free from the radionuclide uptake, the solution chemistry of these radiopharmaceuticals was studied by paper chromatography and paper electrophoresis in distilled water, in physiological saline, in NAHCO3, and ascorbic acid solutions. Both radiopharmaceuticals are anionic in the radiopharmaceutical solution but get easily hydrolysed to form cationic Tc-99m species which concentrates in healthy bone and in some bone metastases. Tc-99m (V)-DMSA being more stable remains long in the blood pool giving undesirable presence of the radionuclide in lung, heart and kidneys, in addition to its reduced uptake in bone metastases and in some primaries. We are trying to eliminate these drawbacks of healthy organ uptake of Tc-99-m(V)-DMSA not only to get a clean scintigraphic image of the tumour with this radiopharmaceutical but to extend its formulation, thus obtained, to prepare radiopharmaceutical with Re-188, which is the higher homologue of Tc-99m, for systemic therapy of cancer. Essentially similar solution chemistry of both radiopharmaceuticals suggests that like Tc-99m-MDP, technetium-99m-dimercaptosuccinate is also a complex of tetravalent Tc-99m and not of pentavalent Tc-99m as so far supposed to be. PMID:15506627

Shukla, Shyama Kant; Atzei, Giampiero; Sedda, Antioco Franco; Rossi, Gabriele; Cipriani, Cesidio

2004-01-01

146

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

147

Development of Tc-99m Imaging Agents for Abeta Plaques  

SciTech Connect

Development of SPECT imaging agents based on Tc-99m targeting A? plaques is useful for diagnosis of Alzheimer’s disease (AD). A stilbene derivative, [11C]SB-13, showing promise in detecting senile plaques present in AD patients has been reported previously1,2. Based on the 4’-amino-stilbene core structure we have added substituted groups through which a chelating group, N2S2, was conjugated. We report herein a series of Tc-99m labeled stilbene derivative conjugated with a TcO[N2S2] core. The syntheses of stilbenes containing a N2S2 chelating ligand are achieved by a scheme shown. Lipophilic 99mTc stilbene complexes were successfully prepared and purified through HPLC. Preliminary results of in vitro labeling of brain sections from transgenic mice showed very promising plaque labeling. These 99mTc stilbene derivatives are warranted for further evaluations as potential imaging agents targeting amyloid plaques.

Zhi-Ping, Zhuang; Mei-Ping Kung; Catherihne Hou; Hank F. Kung

2008-09-26

148

In vivo chemistry of 99mTc-chelates.  

PubMed

The structure-activity relationships involved in the in vivo localization and clearance of 99mTc-chelates is reviewed. Most 99mTc-chelates used for renal studies are mixed function agents and their uptake in the kidney is affected by the presence or absence of stannous ions; only a relatively few chelates are almost exclusively cleared from the body by glomerular filtration or tubular excretion. The uptake of 99mTc-phosphates and -phosphonates in metabolically active and metabolically inactive bone and the plasma clearance rate of these complexes depend upon the structure of the complexing ligand. 99mTc-chelates considered optimal for hepatobiliary imaging have a high liver extraction efficiency, are rapidly transported through the liver and have a comparatively slow renal clearance rate. Even though the elucidation of the in vivo behavior of 99mTc-chelates continues, quantitating structure-activity relationships requires that the structure of the chelates be carefully characterized, both before and after injection. PMID:7152711

Eckelman, W C; Volkert, W A

1982-10-01

149

99mTc-ENS ventilation scintigraphy: preliminary study in human volunteers.  

PubMed

Exogenous natural surfactant (ENS) labeled with (99m)Tc ((99m)Tc-ENS, 900-1110 MBq), a new radiopharmaceutical for ventilation scintigraphy, was nebulized during 3 min to five volunteers. For comparative purposes, (99m)Tc-diethylenetriamine pentaacetic acid (DTPA) was studied in the same way. (99m)Tc-ENS images were of at least the same quality as (99m)Tc-DTPA images. However, in smoking volunteers, the (99m)Tc-DTPA images show some areas that seemed to be not well-ventilated, although these areas appeared well-ventilated when the study was performed with (99m)Tc-ENS. These results suggest that (99m)Tc-ENS can be used for ventilation scintigraphy to allow the observation of some areas that cannot been visualized using (99m)Tc-DTPA as ventilation agent. PMID:10773552

Calmanovici, G; Boccio, J; Goldman, C; Hager, A; De Paoli, T; Alak, M; Degrossi, O; García del Río, H; Nicolini, J; Caro, R; Zubillaga, M

2000-02-01

150

Flux-flow behavior in high Tc superconductors  

NASA Astrophysics Data System (ADS)

We have been exploring flux-flow behavior in high temperature superconductor material by numerically solving Ginzburg-Landau (GL) equation and comparing it to experimental results. Surprisingly, without incorporating phenomenological activation energy and pinning force models and despite the approximate nature of GL equation, the power law IV curves with different exponents are obtained based on the relative magnitudes of normal conductivity ? and ?, the ratio between the London penetration depth (?) and the coherence length (?). Simulations demonstrate that, for typical ? and ? values, vortices of opposite magnetic field polarity are created at two boundaries of the high Tc material and when they reach the center, they pass through and are injected into opposite polarity sides. Injection and what it entails shed light on unexplained high Tc behavior, open ways for practical applications, eliminate the need for phenomenological models, help us to understand and predict high Tc flux-flow properties.

Raissi, F.; Hassani, F.

2014-06-01

151

Bec Model of HIGH-Tc Superconductivity in Layered Cuprates  

NASA Astrophysics Data System (ADS)

High-Tc superconductivity in layered cuprates is described in a BCS-BEC formalism with linearly-dispersive s- and d-wave Cooper pairs moving in quasi-2D finite-width layers around the CuO2 planes. This yields a closed formula for Tc involving the layer width, the Debye frequency, the pairing energy and the in-plane penetration depth. The new formula has no free parameters and reasonably reproduces empirical values of superconducting Tcs for 11 different layered superconductors over a wide doping regime including YBCO itself as well as other compounds like LSCO, BSCCO and TBCCO. In agreement with the London formalism, the formula also yields a fair description of the Tc dependence of the lower critical magnetic field in highly underdoped YBCO.

Lomnitz, M.; Villarreal, C.; de Llano, M.

2013-11-01

152

trans-K3[TcO2(CN)4  

PubMed Central

The structure of the title compound, tripotassium trans-tetra­cyanidodioxidotechnetate(V), is isotypic with its Re analogue. The [TcO2(CN)4]3? trans-tetra­cyanido­dioxido­technetate anion has a slightly distorted octa­hedral configuration. The Tc atom is located on a center of inversion and is bound to two O atoms in axial and to four cyanide ligands in equatorial positions. The Tc—O distance is consistent with a double-bond character. The two potassium cations, one located on a center of inversion and one in a general position, reside in octa­hedral or tetra­hedral environments, respectively. K?O and K?N inter­actions occur in the 2.7877?(19)–2.8598?(15)?Å range.

Chatterjee, Sayandev; Del Negro, Andrew S.; Edwards, Matthew K.; Twamley, Brendan; Krause, Jeanette A.; Bryan, Samuel A.

2010-01-01

153

trans-K(3)[TcO(2)(CN)(4)].  

PubMed

The structure of the title compound, tripotassium trans-tetra-cyanidodioxidotechnetate(V), is isotypic with its Re analogue. The [TcO(2)(CN)(4)](3-)trans-tetra-cyanido-dioxido-technetate anion has a slightly distorted octa-hedral configuration. The Tc atom is located on a center of inversion and is bound to two O atoms in axial and to four cyanide ligands in equatorial positions. The Tc-O distance is consistent with a double-bond character. The two potassium cations, one located on a center of inversion and one in a general position, reside in octa-hedral or tetra-hedral environments, respectively. K?O and K?N inter-actions occur in the 2.7877?(19)-2.8598?(15)?Å range. PMID:21588082

Chatterjee, Sayandev; Del Negro, Andrew S; Edwards, Matthew K; Twamley, Brendan; Krause, Jeanette A; Bryan, Samuel A

2010-01-01

154

99mTcO4?-, Auger-Mediated Thyroid Stunning: Dosimetric Requirements and Associated Molecular Events  

PubMed Central

Low-energy Auger and conversion electrons deposit their energy in a very small volume (a few nm3) around the site of emission. From a radiotoxicological point of view the effects of low-energy electrons on normal tissues are largely unknown, understudied, and generally assumed to be negligible. In this context, the discovery that the low-energy electron emitter, 99mTc, can induce stunning on primary thyrocytes in vitro, at low absorbed doses, is intriguing. Extrapolated in vivo, this observation suggests that a radioisotope as commonly used in nuclear medicine as 99mTc may significantly influence thyroid physiology. The aims of this study were to determine whether 99mTc pertechnetate (99mTcO4?) is capable of inducing thyroid stunning in vivo, to evaluate the absorbed dose of 99mTcO4? required to induce this stunning, and to analyze the biological events associated/concomitant with this effect. Our results show that 99mTcO4?–mediated thyroid stunning can be observed in vivo in mouse thyroid. The threshold of the absorbed dose in the thyroid required to obtain a significant stunning effect is in the range of 20 Gy. This effect is associated with a reduced level of functional Na/I symporter (NIS) protein, with no significant cell death. It is reversible within a few days. At the cellular and molecular levels, a decrease in NIS mRNA, the generation of double-strand DNA breaks, and the activation of the p53 pathway are observed. Low-energy electrons emitted by 99mTc can, therefore, induce thyroid stunning in vivo in mice, if it is exposed to an absorbed dose of at least 20 Gy, a level unlikely to be encountered in clinical practice. Nevertheless this report presents an unexpected effect of low-energy electrons on a normal tissue in vivo, and provides a unique experimental setup to understand the fine molecular mechanisms involved in their biological effects.

Cambien, Beatrice; Franken, Philippe R.; Lamit, Audrey; Mauxion, Thibault; Richard-Fiardo, Peggy; Guglielmi, Julien; Crescence, Lydie; Mari, Bernard; Pourcher, Thierry; Darcourt, Jacques; Bardies, Manuel; Vassaux, Georges

2014-01-01

155

99mTcO4--, auger-mediated thyroid stunning: dosimetric requirements and associated molecular events.  

PubMed

Low-energy Auger and conversion electrons deposit their energy in a very small volume (a few nm3) around the site of emission. From a radiotoxicological point of view the effects of low-energy electrons on normal tissues are largely unknown, understudied, and generally assumed to be negligible. In this context, the discovery that the low-energy electron emitter, 99mTc, can induce stunning on primary thyrocytes in vitro, at low absorbed doses, is intriguing. Extrapolated in vivo, this observation suggests that a radioisotope as commonly used in nuclear medicine as 99mTc may significantly influence thyroid physiology. The aims of this study were to determine whether 99mTc pertechnetate (99mTcO4-) is capable of inducing thyroid stunning in vivo, to evaluate the absorbed dose of 99mTcO4- required to induce this stunning, and to analyze the biological events associated/concomitant with this effect. Our results show that 99mTcO4--mediated thyroid stunning can be observed in vivo in mouse thyroid. The threshold of the absorbed dose in the thyroid required to obtain a significant stunning effect is in the range of 20 Gy. This effect is associated with a reduced level of functional Na/I symporter (NIS) protein, with no significant cell death. It is reversible within a few days. At the cellular and molecular levels, a decrease in NIS mRNA, the generation of double-strand DNA breaks, and the activation of the p53 pathway are observed. Low-energy electrons emitted by 99mTc can, therefore, induce thyroid stunning in vivo in mice, if it is exposed to an absorbed dose of at least 20 Gy, a level unlikely to be encountered in clinical practice. Nevertheless this report presents an unexpected effect of low-energy electrons on a normal tissue in vivo, and provides a unique experimental setup to understand the fine molecular mechanisms involved in their biological effects. PMID:24663284

Cambien, Béatrice; Franken, Philippe R; Lamit, Audrey; Mauxion, Thibault; Richard-Fiardo, Peggy; Guglielmi, Julien; Crescence, Lydie; Mari, Bernard; Pourcher, Thierry; Darcourt, Jacques; Bardiès, Manuel; Vassaux, Georges

2014-01-01

156

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

157

Tc Enhancement in Electron-Doped Cuprate Heterostructures  

NASA Astrophysics Data System (ADS)

Multilayer thin films of La2-xCexCuO4 (LCCO) and Pr2-xCexCuO4 (PCCO) were fabricated as superlattices of different dopings. Pairing over-doped and under-doped (or un-doped) layers is found to increase Tc significantly above that of the single-phase films corresponding to the under- or over-doped layers. We report transport measurements on these mulitlayer films and discuss possible mechanisms for the Tc enhancement. This work was supported by the US-Israel Binational Science Foundation Grant #2006385 and the Center for Nanophysics and Advanced Materials (CNAM).

Bach, P. L.; Jin, K.; Zhang, X. H.; Greene, R. L.; Grupel, U.; Zohar, E.; Diamant, E.; Dagan, Y.; Smadici, S.; Abbamonte, P.

2011-03-01

158

Rugged Low-Resistance Contacts To High-Tc Superconductors  

NASA Technical Reports Server (NTRS)

Newly developed technique involving use of gold makes possible to fabricate low-resistance contacts with rugged connections to high-Tc superconductors. Gold diffused into specimen of superconducting material by melting gold beads onto surface of specimen, making strong mechanical contacts. Shear strength of gold bead contacts greater than epoxy or silver paste. Practical use in high-current-carrying applications of new high-Tc materials, including superconducting magnets, long-wavelength sensors, electrical ground planes at low temperatures, and efficient transmission of power.

Caton, Randall; Selim, Raouf; Byvik, Charles E.; Buoncristiani, A. Martin

1992-01-01

159

High Tc superconducting bolometric and nonbolometric infrared (IR) detectors  

NASA Technical Reports Server (NTRS)

The original workplan for the first year of the project includes the following: establishment of a pilot superconductivity application laboratory at UDC to support the research component of the project; research on the source of electrical noise in High Tc superconducting films in order to optimize the film microstructure and lower the NEP; and lay the foundation of an academic support for exposing UDC students to the theory and application of High Tc superconductivity. Attached to this status report are abstracts and the course description for Introduction to Applications of Superconductivity.

Lakeou, Samuel

1994-01-01

160

Validation of an alternative radiochemical purity method for [99mTc]pentetate ([99mTc]DTPA).  

PubMed

[(99m)Tc]pentetate ([(99m)Tc]DTPA) is the most commonly used radiopharmaceutical renography agent. The aim of this work was to validate an alternative method for assessing [(99m)Tc]DTPA radiochemical purity (RCP), according to the ICH Q2(R1) guidance: "Validation of Analytical Procedures". The proposed method is composed of two chromatographic systems. System A is a miniaturized system of thin layer chromatography (TLC) silica gel impregnated aluminum strips as stationary phase (SP) and distilled water as mobile phase (MP). System B consists of Whatman 1 paper strips as SP and methyl ethyl ketone as MP. Results indicate that the proposed RCP method has been validated, as it is specific, precise, accurate, linear and robust. Therefore, it can be used as an alternative method for RCP quality control purposes and as stability indicator as well. PMID:24140984

Borré, María Candela; Tesán, Fiorella C; Leonardi, Natalia M; Zubillaga, Marcela B; Salgueiro, M Jimena

2013-12-01

161

Tc-99 Adsorption on Selected Activated Carbons - Batch Testing Results  

SciTech Connect

CH2M HILL Plateau Remediation Company (CHPRC) is currently developing a 200-West Area groundwater pump-and-treat system as the remedial action selected under the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision for Operable Unit (OU) 200-ZP-1. This report documents the results of treatability tests Pacific Northwest National Laboratory researchers conducted to quantify the ability of selected activated carbon products (or carbons) to adsorb technetium-99 (Tc-99) from 200-West Area groundwater. The Tc-99 adsorption performance of seven activated carbons (J177601 Calgon Fitrasorb 400, J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, J177612 Norit GAC830, J177613 Norit GAC830, and J177617 Nucon LW1230) were evaluated using water from well 299-W19-36. Four of the best performing carbons (J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, and J177613 Norit GAC830) were selected for batch isotherm testing. The batch isotherm tests on four of the selected carbons indicated that under lower nitrate concentration conditions (382 mg/L), Kd values ranged from 6,000 to 20,000 mL/g. In comparison. Under higher nitrate (750 mg/L) conditions, there was a measureable decrease in Tc-99 adsorption with Kd values ranging from 3,000 to 7,000 mL/g. The adsorption data fit both the Langmuir and the Freundlich equations. Supplemental tests were conducted using the two carbons that demonstrated the highest adsorption capacity to resolve the issue of the best fit isotherm. These tests indicated that Langmuir isotherms provided the best fit for Tc-99 adsorption under low nitrate concentration conditions. At the design basis concentration of Tc 0.865 µg/L(14,700 pCi/L), the predicted Kd values from using Langmuir isotherm constants were 5,980 mL/g and 6,870 mL/g for for the two carbons. These Kd values did not meet the target Kd value of 9,000 mL/g. Tests conducted to ascertain the effects of changing pH showed that at pH values of 6.5 and 7.5, no significant differences existed in Tc-adsorption performance for three of the carbons, but the fourth carbon performed better at pH 7.5. When the pH was increased to 8.5, a slight decline in performance was observed for all carbons. Tests conducted to ascertain the temperature effect on Tc-99 adsorption indicated that at 21 ºC, 27 ºC, and 32 ºC there were no significant differences in Tc-99 adsorption for three of the carbons. The fourth carbon showed a noticeable decline in Tc-99 adsorption performance with increasing temperature. The presence of volatile organic compounds (VOCs) in the source water did not significantly affect Tc-99 adsorption on either of two carbons tested. Technetium-99 adsorption differed by less than 15% with or without VOCs present in the test water, indicating that Tc-99 adsorption would not be significantly affected if VOCs were removed from the water prior to contact with carbon.

Mattigod, Shas V.; Wellman, Dawn M.; Golovich, Elizabeth C.; Cordova, Elsa A.; Smith, Ronald M.

2010-12-01

162

Standards and biomedical terminologies: the CEN TC 251 and ISO TC 215 categorial structures. A step towards increased interoperability.  

PubMed

Among different biomedical terminologies standardisation strategies the European Standard Body CEN TC 251 followed by the ISO TC 215 have stated that it was not possible to convince the different European or international member states using different national languages to agree on a reference clinical terminology or to standardise a detailed language independent biomedical ontology. Since 1990, they have developed an approach named categorial structure as a step standardising only the terminologies model structure. The methodology and the review of the different existing categorial structures are presented as a step towards increased interoperability between biomedical terminologies thanks to conformity to a minimum set of ontological requirements. PMID:18487839

Rodrigues, Jean M; Kumar, Anand; Bousquet, Cédric; Trombert, Béatrice

2008-01-01

163

High Tc SQUID Detector for Magnetic Metallic Particles in Products  

NASA Astrophysics Data System (ADS)

High-Tc superconducting quantum interference device (SQUID) is an ultra-sensitive magnetic sensor. After the discovery of the high-Tc superconducting materials, the performance of the high-Tc SQUID has been improved and stabilized. One strong candidate for application is a detection system of magnetic foreign matters in industrial products. There is a possibility that ultra-small metallic foreign matter has been accidentally mixed with industrial products such as lithium ion batteries. If this happens, the manufacturer of the product suffers a great loss recalling products. The outer dimension of metallic particles less than 100 micron cannot be detected using X-ray imaging, which is commonly used for the inspection. Therefore a highly sensitive system for small foreign matters is required. We developed detection systems based on high-Tc SQUID for industrial products. We could successfully detect small iron particles of less than 50 micron on a belt conveyer. These detection levels were hard to be achieved using conventional X-ray detection or other methods.

Tanaka, Saburo; Akai, Tomonori; Hatsukade, Yoshimi; Suzuki, Shuichi

164

Indian pharmaceutical introduces low-priced 3TC.  

PubMed

An Indian pharmaceutical company has introduced its own brand of Lamivudine (3TC) to the Indian and overseas market. Cipla is offering Lamivir at a price that is less than half that of Glaxo. Lamivir is priced at $1.20 for each 150 mg tablet, compared with $2.80 to $5.80 for Glaxo's Epivir. PMID:11367089

1998-12-01

165

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

166

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

167

Authentic Learning Situations and the Potential of Lego TC Logo.  

ERIC Educational Resources Information Center

Considers the potential of Lego TC Logo, a product that integrates Lego building materials with computers, for creating contexts for learning that give elementary school students a sense that their work is authentic. Topics include the concept of authentic learning situations; consequences of unauthentic classrooms; cooperation; and evaluation.…

Lafer, Stephen; Markert, Andrew

1994-01-01

168

PCP/PFP programming models on the BBN TC2000.  

National Technical Information Service (NTIS)

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 describ...

E. D. Brooks B. C. Gorda K. H. Warren

1991-01-01

169

Superconducting fluctuations and pseudogap in high-Tc cuprates  

NASA Astrophysics Data System (ADS)

Large pulsed magnetic fields up to 60 Tesla are used to suppress the contribution of superconducting fluctuations (SCF) to the ab-plane conductivity above Tc in a series of YBa2Cu3O6+x. These experiments allow us to determine the field Hc'(T) and the temperature Tc' above which the SCFs are fully suppressed. A careful investigation near optimal doping shows that Tc' is higher than the pseudogap temperature T*, which is an unambiguous evidence that the pseudogap cannot be assigned to preformed pairs. Accurate determinations of the SCF contribution to the conductivity versus temperature and magnetic field have been achieved. They can be accounted for by thermal fluctuations following the Ginzburg-Landau scheme for nearly optimally doped samples. A phase fluctuation contribution might be invoked for the most underdoped samples in a T range which increases when controlled disorder is introduced by electron irradiation. Quantitative analysis of the fluctuating magnetoconductance allows us to determine the critical field Hc2(0) which is found to be be quite similar to Hc' (0) and to increase with hole doping. Studies of the incidence of disorder on both Tc' and T* allow us to to propose a three dimensional phase diagram including a disorder axis, which allows to explain most observations done in other cuprate families.

Rullier-Albenque, F.; Alloul, H.

2012-03-01

170

Tc-99m HMPAO brain SPECT scanning in Munchausen syndrome.  

PubMed Central

Regional cerebral blood flow was studied in a patient with Munchausen syndrome using high resolution Tc-99m HMPAO SPECT. The scan demonstrated marked hyperperfusion of the right hemithalamus. The cranial CT scan was normal. The abnormal right hemithalamic blood flow is discussed in relation to the hypothesized neuropathy of this disorder. Images Figure 1 Figure 2 Figure 3

Mountz, J M; Parker, P E; Liu, H G; Bentley, T W; Lill, D W; Deutsch, G

1996-01-01

171

High Tc Superconductors: New Insights from Angle-Resolved Photoemission  

Microsoft Academic Search

Recent angle-resolved photoemission (ARPES) studies of the high Tc superconductors are reviewed. Amongst the topics discussed are: the spectral function interpretation of ARPES data and sum rules; studies of the momentum distribution and the Fermi surface (FS); dispersion of electronic states, flat bands and superlattice effects; unusual lineshapes and their temperature dependence; the question of bilayer splitting; detailed studies of

Mohit Randeria; Juan-Carlos Campuzano

1997-01-01

172

Magnetization of High tc Superconducting Ba-Y-Cu-O  

Microsoft Academic Search

Magnetizition of high Tc Ba-Y-Cu-O are measured at temperature of 1.5K-200K and magnetic feild up to 7T. The magnetization curves exhibit hysteresis. However the superconducting current density is very low. Magnetization slopes of different temperature at Meissner state are the same. It means that the superconducting phase is ``bulk''.

Shuquan Guo; Qiansheng Yang; Guirong Liu; Changgeng Cui; Shanlin Li; Yuzhen Huang; Genhua Chen; Jianqing Bi; Liquan Chen; Zhongxian Zhao

1987-01-01

173

A comparison between the diagnostic efficacy of 99m Tc-MDP, 99m Tc-DPD and 99m Tc-HDP for the detection of bone metastases  

Microsoft Academic Search

We have investigated the clinical efficacy for the detection of bone metastases of two recently marketed bone-seeking radiopharmaceuticals, HDP and DPD, compared with traditionally used MDP. Twenty patients received 15 mCi 99mTc-MDP; after assessment ten of these patients later received 15 mCi 99mTc-DPD and ten other patients of this group were injected with 15 mCi 99mTc-HDP. Scintigraphy took place 3

E. K. J. Pauwels; J. Blom; J. A. J. Camps; J. Hermans; A. M. Rijke

1983-01-01

174

Clinical comparison of /sup 99m/Tc-diethyl-IDA and /sup 99m/Tc-PIPIDA for evaluation of the hepatobiliary system  

SciTech Connect

Fifteen patients with a wide range of hepatobiliary function were studied with both /sup 99m/Tc-diethyl-IDA and /sup 99m/Tc-PIPIDA. In images obtained 5 to 60 minutes after injection, /sup 99m/Tc-diethyl-IDA was clearly superior with respect to liver/background, hepatic ducts/liver, and small bowel/background ratios. The /sup 99m/Tc-diethyl-IDA transit time from blood to small intestine averaged 12.2 minutes less than that of /sup 99m/Tc-PIPIDA. Quantification of relative hepatocyte extraction efficiency indicated that it was 2.15 times higher for /sup 99m/Tc-diethyl-IDA. Cumulative 3-hour urine collections following injection demonstrated increasing renal excretion of /sup 99m/Tc-PIPIDA with rising total serum bilirubin levels in a manner quantitatively similar to that determined previously for /sup 99m/Tc-diethyl-IDA. The authors conclude that /sup 99m/Tc-diethyl-IDA is superior to /sup 99m/Tc-PIPIDA for studies of the hepatobiliary system.

Klingensmith, W.C.; Fritzberg, A.R.; Spitzer, V.M.; Koep, L.J.

1980-01-01

175

The Settlement for the Debate on the Penetration Depth Experiments in the HIGH-Tc Cuprates  

Microsoft Academic Search

This paper shows that the cuprates being of higher than 80 K Tc have two types of dependences of the penetration depth on temperature, which can settle the debates of the penetration depth experiments in the high-Tc cuprates.

Fu-Sui Liu; Jing-Yi Wang

1996-01-01

176

Split-join and message passing programming models on the BBN TC2000.  

National Technical Information Service (NTIS)

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 impleme...

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

1991-01-01

177

Vibration reduction using autoparametric resonance in a high-Tc superconducting levitation system  

NASA Astrophysics Data System (ADS)

High-Tc superconducting levitation systems have very small damping and enable stable levitation without control. Therefore, they can be applied to various kinds of application. However, there are some problems that small damping produces large vibration and nonlinearity of magnetic force can generate complicated phenomena. Accordingly, analysis of these phenomena and reduction of vibration occurring in the system are important. In this study, we examined reduction of vibration without using any absorbers, but utilizing autoparametric resonance caused by nonlinear coupling between vertical oscillation and horizontal oscillation. We conducted numerical analysis and experiments in order to investigate motions of a rigid bar levitated by the electromagnetic force from high-Tc superconductors. As a result, if the ratio of the natural frequency of vertical oscillation and that of horizontal oscillation is two to one, the vertical oscillation decreases while the horizontal oscillation is excited. Thus, it was confirmed that the amplitude of a primary resonance can be reduced by occurrence of autoparametric resonance without using any absorbers.

Yamasaki, Hiroshi; Takazakura, Toyoki; Sakaguchi, Ryunosuke; Sugiura, Toshihiko

2014-05-01

178

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

179

Decomposition of Tc99m pyrophosphate by peroxides in pertechnetate used in preparation  

Microsoft Academic Search

We describe an investigation of the stability of Tc-99m pyrophosphate (Tc-99m PPi). We have shown that addition of exogenous hydrogen peroxide to Tc-99m PPi can initiate the oxidation of the complex, giving rise to 95% unbound pertechnetate. The presence of endogenous hydrogen peroxide in the sodium pertechnetate used in the preparation of Tc-99m PPi has been thought to influence its

M. Der; J. R. Ballinger; B. M. Bowen

1981-01-01

180

Decomposition of Tc99m pyrophosphate by peroxides in pertechnetate used in preparation  

Microsoft Academic Search

We describe an investigation of the stability of Tc-99m pyrophosphate (Tc-99m PPi). We hve shown that addition of exogenous hydrogen peroxide to Tc-99m PPi can initiate the oxidation of the complex, giving rise to 95% unbound pertechnetate. The presence of endogenous hydrogen peroxide in the sodium pertechnetate used in the preparation of Tc-99m PPi has been thought to influence its

M. Der; J. R. Ballinger; B. M. Bowen

1981-01-01

181

Moving from CEN TC 287 to ISO\\/TC 211 - The approach of the Portu- guese National Geographic Information Infrastructure  

Microsoft Academic Search

This paper describes the work, currently ongoing, that will lead to the development of a web- based application to allow GI producers to manage their metadata, according to the ISO TC 211 recommendations. To guarantee the interoperability between the different organizations, the metadata is stored in XML documents. After the formal discussion of the GI metadata normalization initiatives, the CNIG

Cristina Gouveia; Pedro Henriques; Rita Nicolau; Jorge Rocha; Maribel Santos

182

Computer analysis of Tc-99m DPD and Tc-99m MDP kinetics in humans: concise communication  

SciTech Connect

Technetium-99m DPD and Tc-99m(Sn)MDP were compared regarding the quality of skeletal images and the compartmental kinetic data, in two groups of nine normal subjects. No difference in scan quality was found. Data derived from compartmental kinetic analysis suggest that MDP has a higher bone uptake and a lower soft-tissue retention in comparison with DPD.

Mele, M.; Conte, E.; Fratello, A.; Pasculli, D.; Pieralice, M.; D'Addabbo, A.

1983-04-01

183

Standardization of Tc-99 by two methods and participation at the CCRI(II)-K2. Tc-99 comparison.  

PubMed

The work accomplished within the participation at the 2012 key comparison of Tc-99 is presented. The solution was standardized for the first time in IFIN-HH by two methods: LSC-TDCR and 4?(PC)?-? efficiency tracer. The methods are described and the results are compared. For the LSC-TDCR method, the program TDCR07c, written and provided by P. Cassette, was used for processing the measurement data. The results are 2.1% higher than when applying the TDCR06b program; the higher value, calculated with the software TDCR07c, was used for reporting the final result in the comparison. The tracer used for the 4?(PC)?-? efficiency tracer method was a standard (60)Co solution. The sources were prepared from the mixture (60)Co+(99)Tc solution and a general extrapolation curve, type: N(?Tc-99)/(M)(Tc-99)=f [1-?(Co-60)], was drawn. This value was not used for the final result of the comparison. The difference between the values of activity concentration obtained by the two methods was within the limit of the combined standard uncertainty of the difference of these two results. PMID:24485948

Sahagia, M; Antohe, A; Ioan, R; Luca, A; Ivan, C

2014-05-01

184

Feshbach Shape Resonance for High Tc Pairing in Superlattices of Quantum Stripes and Quantum Wells  

Microsoft Academic Search

The Feshbach shape resonances in the interband pairing in superconducting superlattices of quantum wells or quantum stripes is shown to provide the mechanism for high Tc superconductivity. This mechanism provides the Tc amplification driven by the architecture of material: superlattices of quantum wells (intercalated graphite or diborides) and superlattices of quantum stripes (doped high Tc cuprate perovskites) where the chemical

Antonio Bianconi; P. Aldo Moro

2008-01-01

185

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

186

The Development of the Therapeutic Community in Correctional Establishments: A Comparative Retrospective Account of the ‘DEMOCRATIC’ Maxwell Jones TC and the Hierarchical Concept-Based TC in Prison  

Microsoft Academic Search

Background: The correction-based therapeutic community (TC) is one of the most described treatment modalities for (substance abusing) incarcerated offenders. The origins and development of the therapeutic community have been traced back to two independent traditions: the American hierarchical conceptbased TC and the British democratic Maxwell Jones-type TC. Both branches have developed independently, targeting different people and tackling diverse problems.Aims: To

Stijn Vandevelde; Eric Broekaert; Rowdy Yates; Martien Kooyman

2004-01-01

187

Uptake and washout of 99mTcV-dimercaptosuccinic acid and 99mTc-sestamibi in the assessment of histological type and grade in breast cancer.  

PubMed

This study was performed to investigate the relationship between histological type and grade, with the uptake and washout of 99mTc-hexakis-2-methoxyisobutylisonitrile (99mTc-sestamibi, 99mTc-MIBI) and 99mTcV-dimercaptosuccinic acid (99mTcV-DMSA) in breast cancer. Forty-five patients with histologically proven breast cancer had previously been referred for 99mTcV-DMSA and/or 99mTc-MIBI scintimammography. Twenty-five of them underwent both 99mTcV-DMSA and 99mTc-MIBI scintigraphy in a double phase study. Lateral prone and anterior supine images were acquired at 15 and 60 min after administration of 740-925 MBq of each radiotracer. Uptake ratios and retention index were calculated and correlated with histology and grade of malignancy. Histology showed eight different histotypes: 77.7% were infiltrating ductal or lobular carcinomas. Mammography was definitely positive in 32/45, indeterminate in 10 and negative in three cases (sensitivity 71%). 99mTcV-DMSA was true positive in 37/40 (sensitivity 92.5%) and 99mTc-MIBI in 28/30 (sensitivity 93.3%) breast cancers. Uptake ratios were significantly higher in ductal than in lobular carcinomas on 99mTcV-DMSA and 99mTc-MIBI scintigrams at early and delayed phases. Grade II carcinomas had significantly lower values of retention index (rapid washout) than grade III carcinomas. This finding was statistically significant only on 99mTc-MIBI scans and was observed in ductal and lobular carcinomas. The retention index did not show any significant difference between ductal and lobular carcinomas. Uptake ratios were also not statistically different between grade II and III cancers. It is concluded that 99mTc-MIBI and 99mTcV-DMSA uptake in breast cancer is probably related to histological type and may distinguish ductal from lobular carcinomas. To a certain degree, the washout rate may reflect the histological grade, but since grade is not the only factor influencing this phenomenon it should be explored further in conjunction with other parameters by multivariate analysis in order to clarify eventual indirect correlations. PMID:11973487

Papantoniou, V; Christodoulidou, J; Papadaki, E; Valotassiou, V; Souvatzoglou, M; Louvrou, A; Feida, H; Sotiropoulou, M; Pampouras, G; Michalas, S; Zerva, C

2002-05-01

188

Studies of skeletal tracer kinetics IV. Optimum time delay for Tc-99m(Sn) methylene disphosphonate bone imaging  

SciTech Connect

The kinetics of the skeletal tracer Tc-99m(Sn)methylene diphosphonate (Tc-MDP) were studied in four older patients without significant bony disease by means of compartmental analysis. Solution of the model was obtained by digital computer techniques. Tracer concentrations for target and background areas (to reflect bone and soft-tissue regions) as time functions were generated for three different imaging criteria: counting rate, a figure of merit, and contrast. The figure of merit reached a maximum early in the second hour after dose administration, but contrast was found to attain a plateau at 6 h. Either of these criteria is in accord with recommendations in the literature for otpimal imaging delay time with Tc-MDP. Bone biopsy in one patient was in good agreement with the model's prediction. Compartmental analysis provides an objective method for determining the optimal imaging delay time, depending on the criterion chosen. The method can be used for any radiopharmaceutical if the compartmental model is known and can be solved.

Makler, P.T. Jr.; Charkes, N.D.

1980-07-01

189

Multi-Channel Magnetocardiogardiography System Based on Low-Tc SQUIDs in an Unshielded Environment  

NASA Astrophysics Data System (ADS)

Magnetocardiography (MCG) using superconducting quantum interference devices (SQUIDs) is a new medical diagnostic tool measuring biomagnetic signals that are generated by the electrical activity of the human heart. This technique is completely passive, contactless, and it has an advantage in the early diagnosis of heart diseases. We developed the first unshielded four-channel MCG system based on low-Tc DC SQUIDs in China. Instead of using a costly magnetically shielded room, the environmental noise suppression was realized by using second-order gradiometers and three-axis reference magnetometer. The measured magnetic field resolution of the system is better than 1 pT, and multi-cycle human heart signals can be recorded directly. Also, with the infrared positioning system, 48 points data collection can be realized by moving the non-magnetic bed nine times.

Kong, Xiangyan; Zhang, Shulin; Wang, Yongliang; Zeng, Jia; Xie, Xiaoming

190

Theory of quantum oscillations in the vortex-liquid state of high-Tc superconductors.  

PubMed

The observation of quantum oscillations in underdoped cuprates has generated intense debate about the nature of the field-induced resistive state and its implications for the 'normal state' of high-Tc superconductors. Quantum oscillations suggest an underlying Fermi liquid at high magnetic fields H and low temperatures, in contrast with the pseudogap seen in zero-field, high-temperature spectroscopic experiments. Recent specific heat measurements show quantum oscillations in addition to a large field-dependent suppression of the electronic density of states. Here we present a theoretical analysis that reconciles these seemingly contradictory observations. We model the resistive state as a vortex liquid with short-range d-wave pairing correlations. We show that this state exhibits quantum oscillations, with a period determined by a Fermi surface reconstructed by a competing order parameter, in addition to a large suppression of the density of states that goes like ?H at low fields. PMID:23591867

Banerjee, Sumilan; Zhang, Shizhong; Randeria, Mohit

2013-01-01

191

A Study of Cirrus Ice Particle Size Distribution Using TC4 Observations  

NASA Technical Reports Server (NTRS)

An analysis of two days of in situ observations of ice particle size spectra, in convectively generated cirrus, obtained during NASA s Tropical Composition, Cloud, and Climate Coupling (TC4) mission is presented. The observed spectra are examined for their fit to the exponential, gamma, and lognormal function distributions. Characteristic particle size and concentration density scales are determined using two (for the exponential) or three (for the gamma and lognormal functions) moments of the spectra. It is shown that transformed exponential, gamma, and lognormal distributions should collapse onto standard curves. An examination of the transformed spectra, and of deviations of the transformed spectra from the standard curves, shows that the lognormal function provides a better fit to the observed spectra.

Tian, Lin; Heymsfield, Gerald M.; Li, Lihua; Heymsfield, Andrew J.; Bansemer, Aaron; Twohy, Cynthia H.; Srivastava, Ramesh C.

2010-01-01

192

The rabbit biodistribution of a therapeutic dose of zoledronic acid labeled with Tc-99m.  

PubMed

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 (99m)Tc-methylene biphosphonate ((99m)Tc-MDP) in normal rabbits. Preparation of 0.50 mg of (99m)Tc-ZOL was carried out by the reduction of (99m)Tc-pertechnetate in the presence of stannous chloride. The radiolabeling efficiency was found to be greater than 99%. The labeled complex was stable at least up to 6 h at room temperature determined by paper chromatography. (99m)Tc-ZOL and (99m)Tc-MDP were administered intravenously to the rabbits for scintigraphic studies. Between (99m)Tc-ZOL and (99m)Tc-MDP, there were no significant differences in the ratios of femur/BG and lumbar vertebrae/BG, whereas epiphysis/BG and the kidney/BG ratios of (99m)Tc-MDP were higher than (99m)Tc-ZOL at the static studies. PMID:19457677

Asikoglu, Makbule; Durak, Funda Gamze

2009-09-01

193

NMR/MRI with hyperpolarized gas and high Tc SQUID  

DOEpatents

A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.

Schlenga, Klaus (Eggenstein, DE); de Souza, Ricardo E. (Recife, BR); Wong-Foy, Annjoe (Berkeley, CA); Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA)

2000-01-01

194

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

195

Point contact measurements on high Tc ceramic superconductors  

NASA Astrophysics Data System (ADS)

Measurements of the ac Josephson effect between Y-Ba-Cu-O and Gd-Ba-Cu-O high-Tc superconductors and either a BCS superconductor or the ceramic itself are reported. The base electrode of the high-Tc material was glued to the inside of an X-band waveguide, and thin Cu leads attached with Ag paint; the needle point for the measurement was either a drawn tip of Pb-Sn solder or In or a sharpened piece of Y-Ba-Cu-O. No supercurrent was observed at 77 K, but at 4.2 K both materials exhibited the ac Josephson effect, with V within a few percent of the theoretical value. The highly nonlinear I-V characteristic is tentatively attributed to a Schottky barrier.

Andersen, Niels Hessel; Johannsen, Ib; Levinsen, Mogens T.

1988-01-01

196

Enhanced dc spin pumping into a fluctuating ferromagnet near TC  

NASA Astrophysics Data System (ADS)

A linear-response formulation of the dc spin pumping, i.e., a spin injection from a precessing ferromagnet into an adjacent spin sink, is developed in view of describing many-body effects caused by spin fluctuations in the spin sink. It is shown that when an itinerant ferromagnet near TC is used as the spin sink, the spin pumping is largely increased owing to the fluctuation enhancement of the spin conductance across the precessing ferromagnet/spin sink interface. As an example, the enhanced spin pumping from yttrium iron garnet into nickel palladium alloy (TC?20 K) is analyzed by means of a self-consistent renormalization scheme, and it is predicted that the enhancement can be as large as tenfold.

Ohnuma, Yuichi; Adachi, Hiroto; Saitoh, Eiji; Maekawa, Sadamichi

2014-05-01

197

New challenges and opportunities for high-Tc superconducting materials  

NASA Astrophysics Data System (ADS)

Since its discovery 100 years ago, superconductivity has captured the imagination of many as a fascinating physical phenomenon which would enable the drastic reduction of energy waste in the electric power grid, high field magnets and large accelerators. Understanding the physics of superconductivity has been advancing along with the discovery of many superconducting materials and tuning their properties. In this talk I will give a brief overview of how the physics of unconventional superconductivity turned out to be intertwined with materials properties, with the emphasis on high-Tc cuprates and the recently discovered Fe-based superconductors. One of the lessons of the last 20 years is that high critical temperatures and upper critical magnetic fields of unconventional superconductors are no longer the main parameters of merit for power applications, which can also be important for the ongoing quest for higher-Tc materials.

Gurevich, Alex

2011-10-01

198

Crystal and molecular structure of tetrameric [Tc(CO){sub 3}Cl]{sub 4}  

SciTech Connect

A single-crystal X-ray structure analysis of [Tc(CO){sub 3}Cl]{sub 4} is performed. The crystals belong to the cubic system, a = 10.322(3) {angstrom}, space group I{bar 4}3m, Z = 2, d{sub calc} = 2.63 g/cm{sup 3}. The crystal lattice is constructed of isolated tetrameric [Tc(CO){sub 3}Cl]{sub 4} with a cubane-like structure. The Tc(CO){sub 3} fragments are bonded to each other through Cl bridges with practically no metal-metal interaction. The total energy and bond multiplicity for [Tc(CO){sub 3}Cl]{sub 4} and the hypothetical related complexes [Tc(CO){sub 3}H]{sub 4}, [Tc(CO){sub 3}]{sub 4}{sup 4+}, and Tc{sub 4}{sup 4+} with different complex geometric parameters are calculated by the extended Hueckel method.

Baturin, N.A.; Grigor`ev, M.S.; Kryuchkov, S.V.; Miroslavov, A.E.; Sidorenko, G.V.; Suglobov, D.N.

1995-01-01

199

First Evaluation of a 99mTc Tricarbonyl Complex, 99mTc(CO)3(LAN), As a New Renal Radiopharmaceutical in Humans  

PubMed Central

99mTc-mercaptoacetyltriglycine (99mTc-MAG3), 99mTc-dd- and ll-ethylene-di-cysteine (99mTc-EC) and 99mTc-mercaptoacetamide-ethylene-cysteine (99mTc-MAEC) contain N3S or N2S2 ligands designed to accommodate the four ligating sites of the {99mTcO}3+ core; they are all excellent renal imaging agents but have renal clearances less than that of 131I-orthoiodohippurate (131I-OIH). To explore the potential of the newly accessible but less polar {99mTc(CO)3}+ core having three ligating sites, we decided to build on the success of 99mTc-EC with its N2S2 ligand and two dangling carboxylates and have chosen an N2S ligand that also has two dangling carboxyls, lanthionine (LANH2), to form 99mTc(CO)3(LAN), a new renal radiopharmaceutical. Methods Biodistribution studies were performed on Sprague-Dawley rats by using 99mTc(CO)3(LAN) isomers, meso-LAN and dd,ll-LAN (an enantiomeric mixture), coinjected with 131I-OIH. Human studies were also performed by coinjecting each 99mTc product (~74 MBq [~2 mCi]) and 131I-OIH (~ 7.4 MBq [~ 0.2 mCi]) into 3 normal volunteers with dual-isotope imaging performed by using a camera system fitted with a high-energy collimator. Blood samples were obtained from 3 to 90 min after injection, and urine samples were obtained at 30, 90 and 180 min. Results Biodistribution studies in rats revealed a rapid blood clearance as well as rapid renal extraction for both preparations, with the dose in urine at 60 min averaging 88% that of 131I-OIH. In humans, both agents provided excellent renal images, with the plasma clearance averaging 228 mL/min for 99mTc(CO)3(meso-LAN) and 176 mL/min for 99mTc(CO)3(dd,ll-LAN), respectively. At 3 hours, both 99mTc(CO)3(meso-LAN) and 99mTc(CO)3(dd,ll-LAN), showed good renal excretion, averaging 85% and 77% that of 131I-OIH, respectively. Plasma protein binding was minimal (10% and 2%), and red cell uptake was similar (24% and 21%) for 99mTc(CO)3(meso-LAN) and 99mTc(CO)3(dd,ll-LAN), respectively. Conclusion Although the plasma clearance and the rate of renal excretion of the 99mTc(CO)3(LAN) complexes are still less than those of 131I-OIH, the results of this first application of a 99mTc tricarbonyl complex as a renal radiopharmaceutical in humans demonstrate that 99mTc(CO)3(LAN) complexes are excellent renal imaging agents and support continued renal radiopharmaceutical development based on the 99mTc tricarbonyl core.

Lipowska, Malgorzata; He, Haiyang; Malveaux, Eugene; Xu, Xiaolong; Marzilli, Luigi G.; Taylor, Andrew

2014-01-01

200

Scintimammographic findings of in situ ductal breast carcinoma in a double-phase study with Tc-99m(V) DMSA and Tc-99m MIBI value of Tc-99m(V) DMSA.  

PubMed

The authors present a case of in situ ductal carcinoma of the breast (DCIS) with no associated mass in a 46-year-old woman examined with Tc-99m MIBI and Tc-99m(V) DMSA scans, which were acquired in separate sessions 10 minutes and 60 minutes after injection. Histologic analysis revealed a small (<1 cm) infiltrating ductal carcinoma located within the DCIS. Mammography showed a cluster of microcalcifications on a very dense parenchymal background. Tc-99m(V) DMSA was characterized as positive for DCIS, especially in the delayed image. Tc-99m MIBI failed to identify the lesions previously noted. In conclusion, Tc-99m(V) DMSA scintimammography seems to have an advantage and could improve the detection of nonpalpable in situ breast carcinomas. PMID:10836691

Papantoniou, V; Sotiropoulou, M; Stipsaneli, E; Louvrou, A; Feda, H; Christodoulidou, J; Pampouras, G; Zerva, C; Keramopoulos, A; Michalas, S

2000-06-01

201

An Overview of ER2 Platform Science during TC4  

Microsoft Academic Search

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

S. Platnick; P. A. Newman

2007-01-01

202

Power Systems Development Facility Gasification Test Run TC08  

SciTech Connect

This report discusses Test Campaign TC08 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 using a particulate control device (PCD). The Transport Gasifier was operated as a pressurized gasifier in air- and oxygen-blown modes during TC08. Test Run TC08 was started on June 9, 2002 and completed on June 29. 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 blown was smooth. The gasifier temperature was varied between 1,710 and 1,770 F at pressures from 125 to 240 psig. The gasifier operates at lower pressure during oxygen-blown mode due to the supply pressure of the oxygen system. In TC08, 476 hours of solid circulation and 364 hours of coal feed were attained with 153 hours of pure oxygen feed. The gasifier and PCD operations were stable in both enriched air and 100 percent oxygen blown modes. The oxygen concentration was slowly increased during the first transition to full oxygen-blown operations. Subsequent transitions from air to oxygen blown could be completed in less than 15 minutes. Oxygen-blown operations produced the highest synthesis gas heating value to date, with a projected synthesis gas heating value averaging 175 Btu/scf. Carbon conversions averaged 93 percent, slightly lower than carbon conversions achieved during air-blown gasification.

Southern Company Services

2002-06-30

203

Fabrication and measurement of high Tc superconducting microbolometers  

Microsoft Academic Search

The authors fabricated and measured the performance of antenna-coupled microbolometers based on the resistive transition of a high-Tc superconducting film for use as detectors of far-infrared and millimeter waves. A planar lithographed antenna (log-periodic or log-spiral) is used to couple the radiation to a thin YBCO film with dimensions (≈6×13 ?m2) which are smaller than the wavelength to be measured.

M. Nahum; Q. Hu; P. L. Richards; S. A. Sachtjen; N. Newman; B. F. Cole

1991-01-01

204

Glycopyrrolate in 99mTc-pertechnetate brain imaging.  

PubMed

Glycopyrrolate, a synthetic anticholinergic agent, was administered parenterally to two groups of patients referred for 99mTc-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 in the parotid gland. The drug can be given orally and may prove valuable in pertechnetate brain imaging. PMID:1159509

Holmes, R A; Luth, C N

1975-09-01

205

Simultaneous determination of radioactive halogen isotopes and 99 Tc  

Microsoft Academic Search

The purpose of this study was to develop a simplified method for simultaneous determination of radiologically important halogen\\u000a isotopes and 99Tc from different types of samples like environmental, biological and waste samples. Due to their long half-lives (longer\\u000a than 105 years) they play important role in the nuclear cycle, especially in environmental monitoring and protection.\\u000a \\u000a For a rapid response in

E. Kabai; N. Vajda; P. Gaca

2003-01-01

206

THE LIMSI 2006 TC-STAR TRANSCRIPTION SYSTEMS  

Microsoft Academic Search

This paper describes the speech recognizers evaluated in the TC-STAR Second Evaluation Campaign held in January- February 2006. Systems were developed to transcribe parlia- mentary speeches in English and Spanish, as well as Broadcast news in Mandarin Chinese. The speech recognizers are state- of-the-art systems using multiple decoding passes with models (lexicon, acoustic models, language models) trained for the dif-

Lori Lamel; Jean-Luc Gauvain; Gilles Adda; Claude Barras; Eric Bilinski; Olivier Galibert; Agusti Pujol; Holger Schwenk; Xuan Zhu

2006-01-01

207

Design of a 1 MVA high Tc superconducting transformer  

Microsoft Academic Search

A 1 MVA transformer using BSCCO-2223 high Tc superconducting (HTS) tapes was designed. The rated voltages of each sides of the transformer for primary and secondary are 22.9 kV and 6.6 kV respectively. Double pancake HTS windings, which have advantages of insulations and distribution of high voltage, were adopted. Four HTS tapes were wound in parallel for the windings of

Woo-Seok Kim; Song-Yop Hahn; Kyeong-Dal Choi; Hyeong-Gil Joo; Kye-Won Hong

2003-01-01

208

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

209

New routes for production of proton-rich Tc isotopes  

NASA Astrophysics Data System (ADS)

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 ?-particle-induced reaction on Nb targets. This article lightens two heavy-ion-induced production routes of Tc93,94,95,96 radionuclides through Li7+natZr and Be9+natY 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 ?-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 Tc94,95 have been compared with those produced from the ?+93Nb reaction.

Maiti, Moumita; Lahiri, Susanta

2010-02-01

210

High-Tc SQUID magnetometer system with active cancellation  

NASA Astrophysics Data System (ADS)

Recent developments of high-Tc SQUIDs have enabled high sensitivity magnetometers to be used in wide range of places, such as laboratory and outdoor fields. At the early stage of developing multichannel system for measurement of magnetocardiogram (MCG) in clinical application, we have fabricated a single channel high-Tc SQUID magnetometer system. The system includes a direct-coupled SQUID with slot structure, a simple magnetically shielded room (MSR), and some active compensation electronics for the purpose of reducing various environmental field noises. A novel active noise cancellation was made by using a combination of a normal conducting detection coil that was horizontally wound in the middle height of the MSR, and two compensation coils that were wound at the top and bottom of the MSR. In addition, adaptive noise cancellation was supplemented by means of adaptive digital filter that was implemented in a digital signal processor. A total noise field attenuation of 50-60 dB was attained at 0.5-100 Hz. Low noise signals from the human heart were measured with a high-Tc SQUID in the noise reduced space in the MSR. .

Kuriki, S.; Oyama, H.; Hayashi, A.; Washio, T.; Fujita, M.; Hirata, Y.

2002-05-01

211

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

212

Fiscal Year 2010 Summary Report on the Epsilon-Metal Phase as a Waste Form for 99 Tc  

SciTech Connect

Epsilon metal (?-metal) is generated in nuclear fuel during irradiation. This metal consists of Pd, Ru, Rh, Mo, and some Te. These accumulate at the UO2 grain boundaries as small (ca 5 µm) particles. These metals have limited solubility in the acid used to dissolve fuel during reprocessing and in typical borosilicate glass. These must be treated separately to improve overall waste loading in glass. This low solubility and their survival in 2 Gy-old natural reactors led us to investigate them as a waste form for the immobilization of 99Tc and 107Pd, two very long-lived isotopes.

Strachan, Denis M.; Crum, Jarrod V.; Buck, Edgar C.; Riley, Brian J.; Zumhoff, Mac R.

2010-09-30

213

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

214

Comparison of the history effects in magnetization in weakly pinned crystals of high Tc and low Tc superconductors  

NASA Astrophysics Data System (ADS)

A comparison of the history effects in weakly pinned single crystals of a high Tc YBa2Cu3O7-? (for H || c) and a low Tc Ca3Rh4Sn13, which show anomalous variations in critical current density Jc(H), is presented via the tracings of the minor magnetization hysteresis loops using a vibrating sample magnetometer. The sample histories focussed are: (i) the field cooled (FC), (ii) the zero field cooled (ZFC) and (iii) an isothermal reversal of field from the normal state. An understanding of the results in terms of the modulation in the plastic deformation of the elastic vortex solid and supercooling across the order-disorder transitions is sought.

Pal, D.; Sarkar, S.; Tulapurkar, A.; Ramakrishnan, S.; Grover, A. K.; Ravikumar, G.; Dasgupta, D.; Sarma, Bimal K.; Tomy, C. V.; Balakrishnan, G.; Mck Paul, D.

2002-02-01

215

Clinical comparison of diisopropyl-IDA Tc 99m and diethyl-IDA Tc 99m for evaluation of the hepatobiliary system  

SciTech Connect

Thirty-one patients with a wide range of hepatobiliary function and clinical diagnoses were studied with both diisopropyl-IDA Tc 99m and diethyl-IDA Tc 99m. Images were similar except for an increased liver-to-kidney ratio with diisopropyl-IDA Tc 99m (p less than 0.01) and a tendency toward an increased liver-to-background ratio at five minutes with diisopropyl-IDA Tc 99m (p greater than 0.05). Quantification of the relative hepatocyte extraction efficiency indicated a 16% higher extraction efficiency for diisopropyl-IDA Tc 99m (p greater than 0.05). Cumulative three-hour urine collections following injection demonstrated no significant difference in renal excretion in patients with normal total serum bilirubin levels. Both radiopharmaceuticals demonstrated increasing renal excretion with increasing total serum bilirubin levels; however, renal excretion of diisopropyl-IDA Tc 99m increased more slowly than excretion of diethyl-IDA Tc 99m (p less than 0.01). We conclude that, while the overall differences between these two radiopharmaceuticals are small, diisopropyl-IDA Tc 99m is superior because of a lower renal excretion rate in patients with decreased hepatocyte function.

Klingensmith, W.C.; Fritzberg, A.R.; Spitzer, V.M.; Kuni, C.C.; Shanahan, W.S.

1981-09-01

216

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

217

Tc-99m-methylene diphosphonate (Tc-99 MDP) and Ga-67 concentration in soft tissue malignant fibrous histiocytoma (MFH): case report.  

PubMed

A case of calcifying soft tissue malignant fibrous histiocytoma (MFH) which showed a concentration of Tc-99m MDP and Ga-67 citrate, is presented. Tc-99m MDP and Ga-67 citrate scintigraphies of the thigh mass were correlated with conventional radiography, computed tomography (CT) and angiography. PMID:8384870

Kida, T; Hoshi, K; Hoshino, R; Fujita, Y; Munakata, S; Yanagisawa, M

1993-02-01

218

The determination of relative renal function in a pediatric population using Tc-99m DTPA and Tc-99m DMSA  

SciTech Connect

Three methods for evaluating relative renal function in a pediatric population were compared. The clinical and nuclear medicine data of 73 patients were reviewed. Pertinent data included patient age, serum creatinine and the referral diagnosis (reflux, hypertension, obstructive uropathy). Time activity curves for renal regions of interest (ROI) were obtained by renography with Tc-99m DTPA, and deconvolved by an externally detected blood pool curve Furosemide was then administered to evaluate the renal collecting system (if indicated). This was followed by DMSA administration. Relative function was determined in 3 ways: 1) Accumulated renal DTPA activity 60-120 sec. following injection. 2) Amplitude of the tubular phase of the deconvolved renal curve and, 3) Accumulated Tc-99m DMSA activity in renal ROI 4 or 24 hrs. post-injection. Regression analysis revealed: 1) The basic relationship of relative functional data obtained by all three methods was not affected by creatinine, age or other factors. 2) The relationship between the three methods is linear and highly correlated. 3) The DMSA values may be predicted from either method of analyzing the DTPA study using appropriate predictor equations. The authors conclude that Tc-99m DMSA, due to its higher cost and more radiation exposure should not be used for the routine evaluation of relative renal function.

Rosen, P.R.; Kuruc, A.; Treves, S.T.

1985-05-01

219

Influence of (99m)Tc-pertechnetate Thyroid Imaging on Radioactive Iodine Uptake.  

PubMed

Objective To observe the influence of (99m)Tc-pertechnetate on radioactive iodine uptake(RAIU)in patients with Graves' disease(GD)hyperthyroidism after thyroid scintigraphy. Methods Totally 40 patients in whom thyrotoxicosis was diagnosed at Peking Union Medical College Hospital from 2013 March to May were recruited,and RAIU were performed in all patients. Gamma-count rates at 1 h,25 h,49 h,73 h and 169 h were examined respectively after intravenous injection of 185 MBq(5mCi)of (99m)Tc-pertechnetate. The counts of (99m)Tc and (131)I as well as effective half-life of (99m)Tc(Teff (99m)Tc)were calculated respectively according to the half-life formula. The ratio of (99m)Tc to background counts(1200)was calculated as a reference value to evaluate biokinetics of (99m)Tc.The relationship between the effective half-life of (99m)Tc(Teff (99m)Tc)and the level of free triiodothyronine(FT3),free thyroxine(FT4),and effective half-life of (131)I(Teff (131)I)were also evaluated. Results After intravenous injection of (99m)Tc-pertechnetate,(99m)Tc counts at 1h,25h,49h,73h and 169h was(440.16±247.35)×10(4),(11.37±10.67)×10(4),(0.13±0.36)×10(4),(-0.1±0.19)×10(4),respectively,and the ratio of (99m)Tc to background at 1h,25 h,and 49 h was 3668,94.75,and 1.08,respectively. The Teff (99m)Tc was (4.41±0.49)h. Inverse correlations were noted between the effective half-life of Teff (131)I and level of FT3(r=-0.503,P=0.003)and FT4(r=-0.516,P=0.002),while no significant correlation was found between the Teff (99m)Tc and FT3,FT4 as well as the Teff (131)I. Conclusions Teff (99m)Tc is 4.41h,(99m)Tc-pertechnetate thyroid imaging does not influence RAIU three days after injection of (99m)Tc-pertechnetate. Teff (99m)Tc shows no correlation with the thyroid hormone level and RAIU of Graves's hyperthyroidism. PMID:24997818

Ning, Guo; Ke, Yang; Yan-Song, Lin; Tong, Wang

2014-06-28

220

Application of Superconductors-High Tc and Otherwise-to Electric Power Generators  

Microsoft Academic Search

Because superconducting magnets are capable of making large magnetic fluxes over large volumes of space with no dissipation and without the need for iron magnetic circuits, they appear to offer distinct advantages for use in electric machinery. In addition to eliminating the field winding losses, superconductors help improve efficiency by increasing flux density, thus shortening the armature conductor length per

James L. Kirtley JR

1988-01-01

221

Lightning-Generated NO(x) Seen By OMI during NASA's TC-4 Experiment: First Results  

NASA Technical Reports Server (NTRS)

We present here case studies identifying upper-tropospheric NO2 produced in convective storms during NASA's Tropical Composition, Cloud and Climate Coupling Experiment (TCi)n July and August 2007. DC8 aircraft missions, flown from the mission base in Costa Rica, recorded in situ NO2 profiles near active storms and in relatively quiet areas. We combine these data with measurements from the Ozone Monitoring Instrument (OMI) on the Aura satellite to estimate the amount of NO2 produced by lightning (LN02) above background levels in the regions influenced by storms. In our analysis, improved off-line processing techniques are employed to minimize known artifacts in the OM1 data. Information on lightning flashes (primarily CG) observed by the surface network operated by the Instituto Costarricense de Electricidad are examined upwind of regions where OM1 indicates enhanced LNO2. Comparisons of the observed flash data with measurements by the TRMM/LIS satellite instrument are used to obtain the lightning detection efficiency for total flashes. Finally, using the NO/NO2 ratio estimated from DC-8 observations, we estimate the average NO(x) production per lightning flash for each case in this study. The magnitudes of the measured NO(x) enhancements are compared with those observed by the DC-8 and with similar OM1 measurements analyzed in mid-latitude experiments.

Bucsela, Eric; Pickering, Kenneth E.; Huntemann, Tabitha; Cohen, Ronald; Perring, Anne; Gleason, James; Blakeslee, Richard; Navarro, Dylana Vargas; Segura, Ileana Mora; Hernandez, Alexia Pacheco; Laporte-Molina, Sadi

2009-01-01

222

Tc and Re Behavior in Borosilicate Waste Glass Vapor Hydration Tests  

SciTech Connect

Technetium (Tc), found in some nuclear wastes, is of particular concern with regard to long-term storage, because of its long-lived radioactivity and high mobility in the environment. Tc and rhenium (Re), commonly used as a non-radioactive surrogate for Tc, were studied to assess their behavior in borosilicate glass under hydrothermal conditions in the Vapor Hydration Test (VHT). X-ray absorption spectroscopy (XAS) and scanning electron microscopy (SEM) measurements were made on the original Tc- and Re-containing glasses and their corresponding VHT samples, and show different behavior for Tc and Re under VHT conditions. XAS indicates that, despite starting with different Tc(IV) and Tc(VII) distributions in each glass, the VHT samples have 100% Tc(IV)O{sub 6} environments. SEM shows complete alteration of the original glass, Tc enrichment near the sample surface, and Tc depletion in the center. Perrhenate (Re(VII)O{sub 4}{sup -}) is dominant in both Re-containing samples before and after the VHT, where Re is depleted near the VHT sample surface and more concentrated toward the center. (authors)

McKeown, David A.; Buechele, Andrew C.; Pegg, Ian L. [Vitreous State Laboratory, Catholic University of America, 620 Michigan Ave., N.E., Washington, DC, 20064 (United States); Lukens, Wayne W.; Shuh, David K. [Actinide Chemistry Group, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720 (United States)

2007-07-01

223

Metabolic comparison of radiolabeled bleomycin and bleomycin-glucuronide labeled with 99mTc.  

PubMed

The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with (99m)Tc ((99m)Tc-BLM and (99m)Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with (99m)Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of (99m)Tc-BLM and (99m)Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for (99m)Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for (99m)Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the (99m)Tc-BLMG was found to be better than that of (99m)Tc-BLM. PMID:21950554

Koçan, Feray; Avc?ba??, Ugur; Unak, Perihan; Müftüler, Fazilet Zümrüt Biber; Içhedef, Cigdem A; Demiro?lu, Hasan; Gümü?er, Fikriye G

2011-10-01

224

TC1(C8orf4) Regulates Hematopoietic Stem/Progenitor Cells and Hematopoiesis  

PubMed Central

Hematopoiesis is a complex process requiring multiple regulators for hematopoietic stem/progenitor cells (HSPC) and differentiation to multi-lineage blood cells. TC1(C8orf4) is implicated in cancers, hematological malignancies and inflammatory activation. Here, we report that Tc1 regulates hematopoiesis in mice. Myeloid and lymphoid cells are increased markedly in peripheral blood of Tc1–deleted mice compared to wild type controls. Red blood cells are small-sized but increased in number. The bone marrow of Tc1?/? mice is normocellular histologically. However, Lin?Sca-1+c-Kit+ (LSK) cells are expanded in Tc1?/? mice compared to wild type controls. The expanded population mostly consists of CD150?CD48+ cells, suggesting the expansion of lineage-restricted hematopoietic progenitor cells. Colony forming units (CFU) are increased in Tc1?/? mice bone marrow cells compared to controls. In wild type mice bone marrow, Tc1 is expressed in a limited population of HSPC but not in differentiated cells. Major myeloid transcriptional regulators such as Pu.1 and Cebp? are not up-regulated in Tc1?/? mice bone marrow. Our findings indicate that TC1 is a novel hematopoietic regulator. The mechanisms of TC1-dependent HSPC regulation and lineage determination are unknown.

Lee, Soyoung; Kim, Jungtae; Park, Surim; Song, Kyuyoung; Lee, Inchul

2014-01-01

225

Development and biological evaluation of ??mTc-sulfonamide derivatives for in vivo visualization of CA IX as surrogate tumor hypoxia markers.  

PubMed

In vivo visualization of tumor hypoxia related markers, such as the endogenous transmembrane protein CA IX may lead to novel therapeutic and diagnostic applications in the management of solid tumors. In this study 4-(2-aminoethyl)benzene sulfonamide (AEBS, K(i) = 33 nM for CA IX) has been conjugated with bis(aminoethanethiol) (BAT) and mercaptoacetyldiglycine (MAG2) tetradendate ligands and the conjugates radiolabelled with (99m)Tc, to obtain anionic and neutral (99m)Tc-labeled sulfonamide derivatives, respectively. The corresponding rhenium analogues were also prepared and showed good inhibitory activities against hCA IX (K(i) = 59-66 nM). In addition, a second generation bis AEBS was conjugated with MAG2 and labeled with (99m)Tc, and the obtained diastereomers were also evaluated in targeting CA IX. Biodistribution studies in mice bearing HT-29 colorectal xenografts revealed a maximum tumor uptake of <0.5% ID/g at 0.5 h p.i for all the tracers. In vivo radiometabolite analysis indicated that at 1 h p.i. MAG? tetradendate ligands were more stable in plasma (>50% intact) compared to the neutral complex (28% intact). This preliminary data suggest that negatively charged (99m)Tc-labeled sulfonamide derivatives with modest lipophilicity and longer circulation time could be promising markers to target CA IX. PMID:24378650

Akurathi, Vamsidhar; Dubois, Ludwig; Celen, Sofie; Lieuwes, Natasja G; Chitneni, Satish K; Cleynhens, Bernard J; Innocenti, Alessio; Supuran, Claudiu T; Verbruggen, Alfons M; Lambin, Philippe; Bormans, Guy M

2014-01-01

226

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

227

The Synthesis and X-ray Structural Characterization of mer and fac isomers of the Technetium(I) Nitrosyl Complex [TcCl2(NO)(PNPpr)  

PubMed Central

The nitrosyl complex H[TcNOCl4] reacts with the tridentate ligand bis[(2-diphenylphosphino)propyl]amine (PNPpr) to yield a mixture of the mer or fac isomers of [TcCl2(NO)(PNPpr)]. In acetonitrile, where the ligand is freely soluble, reaction occurs at room temperature to yield mostly the mer isomer with the linear nitrosyl ligand cis to the amine ligand; and the phosphine ligands arranged in a mutually trans orientation. The reaction in methanol requires reflux to dissolve the lipophilic ligand and generates the fac isomer of [TcCl2(NO)(PNPpr)] as the major product, with the tridentate ligand in a facial arrangement, leaving the chlorides and nitrosyl ligand in the remaining facial sites. The steric bulk of the tridentate ligand's diphenylphophino- moieties results in a significant distortion from octahedral geometry, with the P-Tc-P bond angle expanded to 99.48(4)°. The infrared spectra display absorptions from these nitrosyl ligands in the 1700 and 1800 cm?1 regions for the fac and mer isomers respectively. The ESI(+) mass spectra each display the parent ion at 647 m/z.

Nicholson, T.L.; Mahmood, A.; Refosco, F.; Tisato, F.; Muller, P.; Jones, A.G.

2009-01-01

228

Zirconium Molybdate Gel as a Generator for Technetium-99M.  

National Technical Information Service (NTIS)

A new sup(99m)Tc generator based on zirconium molybdate gel is described. Essentially the gel is a cation ion exchanger which permits the elution of the pertechnetate ion. The high molybdenum content of this gel, its stability under self-irradiation, and ...

J. V. Evans M. E. Shying

1984-01-01

229

The Use of Stannic Molybdate-Mo as a Te-Generator  

Microsoft Academic Search

The preparation of insoluble stannic molybdate precipitate was radiometrically investigated using Na2MoO4-Mo solution. For routine preparation of the precipitate, equal volumes of stannic chloride and sodium molybdate solutions (1.08: 1 M\\/M) were stirred together at 27°C. Stannic molybdate-Mo precipitates prepared from Na2MoO4-Mo solutions are a good source for Tc-generator. Greater than 60% of the precipitate available Tc activity could be

M. A. El-Absy; S. El-Bayoumy

1990-01-01

230

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

231

Neutron generators  

Microsoft Academic Search

In a sealed-off neutron generator containing tritium, for the production ; of neutrons by the D--T reaction, helium-3 gas accumulates owing to radioactive ; decay of the tritium and interferes with the proper operation of the generator. ; In the present generator a sputter-ion pump is sealed to the generator to remove ; the helium3 from the envelope prior to

1974-01-01

232

Critical current measurements of high Tc superconductors in a scanning low temperature cryostat  

SciTech Connect

Maintaining uniformity of properties over long distances is one of the fabrication problems encountered with the new high {Tc} superconductors. Uniform properties are crucial in long tapes or wires with high critical current since local nonuniformities can limit the current carrying capacity of the whole piece. Transport critical currents in high {Tc} superconductors are conventionally measured with the contact 4-point probe DC current-voltage technique. This technique requires contact with the sample and and spatially averages over the region between the two voltage contacts. Two techniques have been used to infer the critical state model. The first uses the net magnetization of a suitably shaped sample in an external magnetic field. The second combines a DC magnetic field with AC induced currents to infer spatial flux profiles. The AC magnetization technique offers an advantage in that it is noncontacting; however, it also averages the measurement over a large area and requires that the sample be shaped and positioned such that it exhibits zero demagnetizing factor. This paper describes a measurement technique and a scanning cryostat assembly that are capable of determining local critical current in a tape or wire with high resolution and without any direct sample electrical contact. A small compensated coil was used to induce AC currents in slab-shaped samples. The coil was situated near the surface on one side of the slab. With this method, the AC probe can be used as a noncontacting dissipation probe, replacing the voltage probe in the 4-point contact method, when an externally driven transport current is used, or by itself as a local critical state generator and dissipation detector. The results are shown to be meaningful even when the internal magnetic field is not uniform due to shape demagnetizing effects. 10 refs., 5 figs.

Telschow, K.L.; O'Brien, T.K.

1991-01-01

233

Hepatocellular carcinoma: uptake of /sup 99m/Tc-IDA in primary tumor and metastasis  

SciTech Connect

Four consecutive cases of proven hepatocellular carcinoma (HCC) showed significant avidity of /sup 99m/Tc-labeled iminodiacetic acids (Tc-IDAs) in preoperative scintigraphy. In one patient, the pulmonary metastasis showed uptake of Tc-IDA. Such scintigraphic findings were obvious only in the delayed scans, performed 2 1/2 - 4 hr after injection. Since Tc-IDAs and bilirubin are functional analogs physiologically, the ability of HCC to concentrate Tc-IDAs may be related to the ability of HCC neoplastic cells to form bile intracellularly. This hypothesis is supported by the fact that intracellular bile granules were found in the tumor cells of all four patients. This suggests a potential for using Tc-IDAs for the specific and preoperative diagnostic of HCC.

Lee, V.W.; O'Brien, M.J.; Devereux, D.F.; Morris, P.M.; Shapiro, J.H.

1984-07-01

234

Hepatocellular carcinoma: uptake of /sup 99/mTc-IDA in primary tumor and metastasis  

SciTech Connect

Four consecutive cases of proven hepatocellular carcinoma (HCC) showed significant avidity of /sup 99/mTc -labeled iminodiacetic acids (Tc- IDAs ) in preoperative scintigraphy. In one patient, the pulmonary metastasis showed uptake of Tc-IDA. Such scintigraphic findings were obvious only in the delayed scans, performed 2 1/2-4 hr after injection. Since Tc- IDAs and bilirubin are functional analogs physiologically, the ability of HCC to concentrate Tc- IDAs may be related to the ability of HCC neoplastic cells to form bile intracellularly. This hypothesis is supported by the fact that intracellular bile granules were found in the tumor cells of all four patients. This suggests a potential for using Tc- IDAs for the specific and preoperative diagnostic of HCC.

Lee, V.W.; O'Brien, M.J.; Devereux, D.F.; Morris, P.M.; Shapiro, J.H.

1984-07-01

235

Behaviour of (99)Tc in aqueous solutions in the presence of iron oxides and microorganisms.  

PubMed

A set of experiments was performed to determine the factors that influence TcO4(-) interaction with Fe-bearing minerals and to explore the effect of microbial activity on the behaviour of Tc(VII) in solution, in the presence of iron oxides under oxidizing medium. Gradual sorption of TcO4(-) (aq) onto wustite/magnetite was observed under alkaline conditions (pH 8-9). No pronounced effect of TcO4(-) (aq) interaction with hematite was observed in the investigating alkaline systems. At low pH values (2.7-4.5), TcO4(-) retention on hematite increases, suggesting that the process is dependent on pH. Sorption of (99)Tc (VII) onto hematite at pH 7.6-8.0 was achieved because of the presence of specific microorganisms. PMID:24607533

Druteikien?, R?ta; Lukšien?, Benedikta; Pe?iulyt?, Dalia; Mažeika, K?stutis; Gudelis, Ar?nas; Baltr?nas, Dalis

2014-07-01

236

Novel Benzofurans with 99mTc Complexes as Probes for Imaging Cerebral ?-Amyloid Plaques  

PubMed Central

Two novel benzofuran derivatives coupled with 99mTc complexes were tested as probes for imaging cerebral ?-amyloid plaques using single photon emission tomography. Although both derivatives bound to A?(1?42) aggregates, 99mTc-BAT-BF showed higher affinity than 99mTc-MAMA-BF. In sections of brain tissue from an animal model of AD, 99mTc-BAT-BF clearly labeled ?-amyloid plaques. In biodistribution experiments using normal mice, 99mTc-BAT-BF displayed high uptake soon after its injection and washed out from the brain rapidly, a highly desirable feature for an imaging agent. 99mTc-BAT-BF may be a potential probe for imaging ?-amyloid plaques in Alzheimer's brains.

2010-01-01

237

Preparation and preclinical pharmacological study on a novel bone imaging agent (99m)Tc-EMIDP.  

PubMed

A novel zoledronic acid (ZL) derivative, 1-hydroxy-2-(2-ethyl-4-methyl-1H-imidazol-1-yl)ethane-1,1-diyldiphosphonic acid (EMIDP), was prepared and labeled with (99)(m)Tc successfully in a high labeling yield and good stability in vitro. The preclinical pharmacological properties of (99)(m)Tc-EMIDP were investigated and compared with (99)(m)Tc-MDP and (99)(m)Tc-ZL. The studies of biodistribution in mice and SPECT bone imaging of the rabbit suggest that (99)(m)Tc-EMIDP has highly selective uptake in the skeletal system and rapid clearance in the soft tissues. The present findings indicate that (99)(m)Tc-EMIDP holds great potential for bone scintigraphy. PMID:20363146

Lin, Jianguo; Luo, Shineng; Chen, Chuanqing; Qiu, Ling; Wang, Yan; Cheng, Wen; Ye, Wanzhong; Xia, Yongmei

2010-09-01

238

Simultaneous determination of radioactive halogen isotopes and 99Tc  

NASA Astrophysics Data System (ADS)

The purpose of this study was to develop a simplified method for simultaneous determination of radiologically important halogen isotopes and 99Tc from different types of samples like environmental, biological and waste samples. Due to their long half-lives (longer than 105 years) they play important role in the nuclear cycle, especially in environmental monitoring and protection. For a rapid response in the evaluation of 129I, 36Cl and 99Tc contamination levels of these samples it is advantageous to combine the existing individual methods. According to the present procedure, iodine, chlorine and technetium are separated selectively from the same sample aliquot followed by the ß-spectrometry of the purified fractions. Increased sensitivities can be achieved by neutron activation (NA) especially in the case of 129I. Our work intends to solve the problem by combining the well-known hot acidic distillation method for iodine separation with the organic extraction process characteristic for technetium separation. The major objective of the work was to separate the disturbing halides from iodine. For this purpose a selective oxidant was applied. For the sample destruction and fractionated distillation an air flow-through installation was used with hot concentrated sulphuric and nitric acids. The trap for iodine contained 3 M NaOH solution. After iodine separation the trap was exchanged for a new one containing the same solution for trapping chlorine or bromine with an addition of 0.01 M KMnO4 solution as an oxidative agent. As expected, the main part of technetium was contained in the acidic residue after distillation. Tc purification was performed by organic extraction with TBP and TEVA column.

Kabai, E.; Vajda, N.; Gaca, P.

2003-01-01

239

Critical current of high Tc superconducting Bi2223/Ag tapes  

NASA Astrophysics Data System (ADS)

The magnetic field dependence of the critical current of various high Tc superconducting Bi2223/Ag tapes indicates that the transport current is carried through two paths: one is through weakly-linked grain boundaries (Josephson junctions); another is through well-connected grains. The critical current flowing through the weakly-linked grain boundaries, ICw, can be characterized by the Fraunhofer-pattern, taking into account the distribution of junction dimension in the tapes. The critical current along the path of well-connected grains, ICs, is a complex exponential function of the applied field depending on the pinning strength in the grains.

Huang, Y. K.; ten Haken, B.; ten Kate, H. H. J.

1998-12-01

240

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

241

TC-Investigator: A Matlab Program to Explore Pseudosections  

NASA Astrophysics Data System (ADS)

Forward modelling of bulk rock compositions to constrain pressures and temperatures of metamorphism based on mineral assemblage is a commonly used technique. The pseudosections produced contain a wealth of information about predicted mineral compositions and abundances that goes far beyond variations in mineral assemblage. A grid of these variations can be contoured using Gibbs free energy minimisation software (such as Theriak-Domino) or precise isopleths calculated for specific quantities in THERMOCALC. We have produced a new piece of software called TC-Investigator that amalgamates these approaches to provide a relatively quick and user friendly way to contour all compositional parameters and mineral modes across a THERMOCALC pseudosection. TC-Investigator takes the postscript pseudosection diagram and creates a grid of points at a user-specified resolution. THERMOCALC is then used to calculate the equilibrium mineral assemblage at each point using an initial starting guess provided by the user (this can be calculated during initial pseudosection calculation). Once all points have been tried, any that failed to calculate are re-tried using interpolated starting guess values from the surrounding points. This procedure is iterated until no more solutions are found. Any remaining unsolved points are then interpolated numerically from surrounding solutions to produce a fully quantified set of mineral modes and compositions. Following calculation, the dataset can be contoured and output as figures, output as a Matlab readable binary structure or selected compositions written to an ASCII text file. Compositional maps created by TC-Investigator have the power to inform the user about compositional variables that are not conventionally considered. The automated calculation method makes it easy to investigate all variables in one go. For example, in metapelitic rocks, garnet shows the variations in composition that are usually contoured, however, these couple to variations in composition within many other minerals all of which can be seen using TC-Investigator. Plots of water content reveal zones in P-T space where there is extremely rapid water production as hydrous minerals breakdown. As new P-T conditions and bulk compositions are explored using improved thermodynamic datasets this software will provide a quick and simple way to identify key compositional and modal variations in the newly modelled mineral systems.

Pearce, Mark; Gazley, Michael; White, Alistair

2014-05-01

242

Magnetic and thermal properties of high Tc super conductors  

Microsoft Academic Search

Measurements of the normal state magnetic susceptibility chi(T) of YBa2Cu3O7, Bi(1.8)Pb(0.2)Sr2CaCu2O(8 + delta), and Bi(2-x)Pb(x)Sr2Ca2Cu3O(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 YBa2Cu3O7 are in excellent agreement with a new calculation of the superconducting fluctuation diamagnetism. From the analysis, an s-wave pairing is inferred

Wonchoon Lee; Wonchoon

1990-01-01

243

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

244

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

245

Ultrafast IR detector response in high Tc superconducting thin films  

NASA Technical Reports Server (NTRS)

The response from a high Tc superconducting multielement optical detector made of a laser deposited Y-Ba-Cu-O thin film has been evaluated. Several microscopic and spectroscopic techniques were used to establish the presence of the correct phase of the thin film. Optical pulses from a laser diode at 830 nm and from a Q-switched CO2-laser at 10.6 microns were used. The detector responded to 50 ps (FWHM) pulses. A comparison between dR/dT of the film and the response amplitude as a function of temperature indicated a bolometric response.

Lindgren, Mikael; Ahlberg, Henrik; Danerud, Martin; Larsson, Anders; Eng, Sverre T.

1991-01-01

246

Radiation damage to mouse testis cells from (\\/sup 99m\\/Tc) pertechnetate  

Microsoft Academic Search

The radiation dose and the biologic damage to mouse testis from intravenously administered (\\/sup 99m\\/Tc) pertechnetate were studied. The dose was measured for penetrating radiations from \\/sup 99m\\/Tc, using calibrated thermoluminescent dosimeters and calculations from the uptake of the nuclide in the testis, and was found to be 4.9 rads per mCi of ⁹⁹Tc. The biologic damage was measured by

T. A. Mian; N. Suzuki; H. J. Glenn; T. P. Haynie; M. L. Meistrich

1977-01-01

247

99mTc-HMPAO as a Tracer of Cerebral Blood Flow in Newborn Infants  

Microsoft Academic Search

Studies on the kinetics of 99mTc-D,L-hexamethylpropylene amine oxime (99mTc-HMPAO) in adults have shown that it is not an ideal tracer of CBF because it underestimates high-flow areas. Knowledge of the kinetics of the tracer is important in evaluating the studies. The kinetics of 99mTc-HMPAO in infants may be different from that in adults, therefore, we examined the cerebral uptake and

Klaus Børch; Gorm Greisen; Klaus Borch

1997-01-01

248

Determination of 99 Tc in reactor loop decontamination liquid waste using extraction chromatography  

Microsoft Academic Search

A new analytical method has been developed to determine99Tc in samples of aqueous radioactive waste containing high levels of60Co (103–106 Bq\\/l) in mixed forms (simple cationic60Co2+ and coordinated complex forms). The method consists of selective extraction of the99Tc with a combination of cation exchange and solid-phase extraction resins under strong acid conditions. Quantification of the isolated99Tc is accomplished using liquid

N. Chuaqui-Offermanns; D. L. Moir

1997-01-01

249

Complexes of technetium(I) ( 99Tc, 99mTc) pentacarbonyl core with ?-acceptor ligands ( tert-butyl isocyanide and triphenylphosphine): Crystal structures of [Tc(CO) 5(PPh 3)]OTf and [Tc(CO) 5(CNC(CH 3) 3)]ClO 4  

Microsoft Academic Search

A procedure was developed for preparing [99mTcX(CO)5] (X=Cl, Br, I) in a reasonable yield by high-pressure carbonylation with CO of 99mTcO4? in aqueous solutions. In the synthesis, the substantial part of the target product is accumulated in the gas phase and can be transferred from the autoclave into various solvents when relieving the pressure. Compounds [99mTcX(CO)5] (X=Cl?, Br?, I?) are

A. E. Miroslavov; A. A. Lumpov; G. V. Sidorenko; E. M. Levitskaya; N. I. Gorshkov; D. N. Suglobov; R. Alberto; H. Braband; V. V. Gurzhiy; S. V. Krivovichev; I. G. Tananaev

2008-01-01

250

Determination of bone turnover by urinary excretion of 99m Tc-MDP  

Microsoft Academic Search

Two metods of estimating bone turnover were investigated. The 24 h whole body retention (WBR) of intravenously injected 99mTc methylene disphosphonate (99mTc-MDP), a precise, accurate, and generally accepted method, was compared with a new, simple, measurement involving assessment of the 24 h urinary excretion (UE) of 99mTc-MDP. The WBR and UE were measured in 50 normal subjects, 10 patients with

Karsten Thomsen; Lisbeth Nilas; Torben Mogensen; Claus Christiansen

1986-01-01

251

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

252

Processing and properties of long-lengths of Ag-clad BSCCO superconductors and high-{Tc} magnets  

SciTech Connect

Long lengths of Ag-clad mono and multicore BSCCO tapes were fabricated by the powder-in-tube technique. The critical current density (J{sub c}) of 125-m-long monocore tapes was {approx}12,000 A/cm{sup 2} (critical current, I{sub c} 20 A) at 77 K. A 230-m-long 37-filament tape carried an I{sub c} of 14 A (corresponding to a J{sub c} of {approx}10,000 A/cm{sup 2}). Pancake-shaped coils were formed from long-length conductors by the wind-and-react approach. High-T{sub c} magnets were then assembled by stacking the pancake coils and connecting them in series. The magnets were tested as a function of applied magnetic fields at 4.2, 27, 64, and 77 K. A magnet containing 480 m of high-{Tc} tape generated a record-high field of 2.6 T at 4.2 K. Another magnet assembled with {approx}770 m of tape generated a field of {approx}1 T at 4.2 K and {approx}0.6 T at 27 K, both in an applied background field of {approx}20 T. Strain tolerance of high-{Tc} tapes was evaluated by measuring J{sub c} retention as a function of applied strain in an 0.5 T applied field at 77 K.

Balachandran, U.; Iyer, A.N.; Jammy, R. [Argonne National Lab., IL (United States). Energy Technology Div.; Haldar, P.; Hoehn, J.G. Jr. [Intermagnetics General Corp., Latham, NY (United States); Suenaga, M. [Brookhaven National Lab., Upton, NY (United States)

1994-10-01

253

The effective temperature in the quenching of coarsening systems to and to below TC  

NASA Astrophysics Data System (ADS)

We overview the general scaling behaviour of the effective temperature in quenches of simple non-disordered systems, such as ferromagnets, to and to below TC. Emphasis is on the behaviour as the dimensionality is varied. Consequences for the shape of the asymptotic parametric representation are derived. In particular, this is always trivial in critical quenches with TC>0. We clarify that the quench to TC = 0 at the lower critical dimensionality dL, cannot be regarded as a critical quench. Implications for the behaviour of the exponent a of the ageing response function in quenches to below TC are developed.

Corberi, Federico; Lippiello, Eugenio; Zannetti, Marco

2004-12-01

254

Splicing removes the Caenorhabditis elegans transposon Tc1 from most mutant pre-mRNAs.  

PubMed Central

The transposable element Tc1 is responsible for most spontaneous mutations that occur in many Caenorhabditis elegans strains. We analyzed the abundance and sequence of mRNAs expressed from five different Tc1 insertions within either hlh-1 (a MyoD homolog) or unc-54 (a myosin heavy chain gene). Each of the mutants expresses substantial quantities of mature mRNA in which most or all of Tc1 has been removed by splicing. Such mRNAs contain small insertions of Tc1 sequences and/or deletions of target gene sequences at the resulting spliced junctions. Most of these mutant mRNAs do not contain premature stop codons, and many are translated in frame to produce proteins that are functional in vivo. The number and variety of splice sites used to remove Tc1 from these mutant pre-mRNAs are remarkable. Two-thirds of the Tc1-containing introns removed from hlh-1 and unc-54 lack either the 5'-GU or AG-3' dinucleotides typically found at the termini of eukaryotic introns. We conclude that splicing to remove Tc1 from mutant pre-mRNAs allows many Tc1 insertions to be phenotypically silent. Such mRNA processing may help Tc1 escape negative selection.

Rushforth, A M; Anderson, P

1996-01-01

255

Tc-99m hexamethylpropylene-amine oxine (HM-PAO) uptake in a bone metastasis  

SciTech Connect

Uptake of Tc-99m Hexamethylpropylene-amine Oxine (HM-PAO) was seen in bone metastases from carcinoma of the lung. The uptake was prominent when compared to Tc-99m MDP, I-123 IMP, and Ga-67 citrate. Brain imaging with Tc-99m HM-PAO and N-isopropyl-p-(I-123) iodoamphetamine (IMP) is now frequently performed. Uptake of these agents has been reported in brain tumors and melanomas. In this report, uptake of Tc-99m HM-PAO in a metastatic lesion in bone is discussed.

Hoshi, H.; Jinnouchi, S.; Sameshima, M.; Uwada, O.; Watanabe, K.

1988-08-01

256

Microprobe analysis of Tc-MIBI in heart cells: calculation of mitochondrial membrane potential.  

PubMed

Hexakis (2-methoxyisobutylisonitrile) technetium-99m (99mTc-MIBI) is a gamma-emitting radiopharmaceutical probe currently in clinical use to evaluate myocardial perfusion. Biochemical and cellular pharmacological studies have suggested that Tc-MIBI, a lipophilic cation, is sequestered in mitochondria in response to transmembrane potentials. To assess directly the subcellular distribution of the probe in heart tissue, cultured chick heart cells were analyzed by electron-probe X-ray microanalysis (EPXMA) following equilibration in micromolar concentrations of carrier-added 99Tc-MIBI, the ground-state radiopharmaceutical. Quantitation of the physiological elements Na, Ca, Mg, K, S, P, and Cl was correlated with exposure to increasing concentrations of 99Tc-MIBI. EPXMA signals indicated that 99Tc-MIBI was concentrated up to 1,000 times into mitochondria in a dose-dependent fashion based on measured Tc content in the mitochondria. Inner membrane potential (delta psi) of individual mitochondria was calculated as -117 mV using the Nernst equation. Concentrations of 99Tc-MIBI > 36 microM caused a significant efflux of K and Mg from the cell, as well as an increase in Cl in the mitochondria. Comparison of cell ultrastructure with conventional electron microscopy at extracellular 99Tc-MIBI concentrations of 36-72 microM showed no changes compared with control. 99Tc-MIBI allows valuable in situ investigation of cellular bioenergetics with EPXMA by quantitation of delta psi. PMID:8338127

Backus, M; Piwnica-Worms, D; Hockett, D; Kronauge, J; Lieberman, M; Ingram, P; LeFurgey, A

1993-07-01

257

Tc-99m tetrofosmin: A new diagnostic tracer for parathyroid imaging  

SciTech Connect

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 parathyroid adenoma. Imaging with Tc-99m tetrofosmin demonstrated similar findings. The abnormal parathyroid gland was an adenoma. 18 refs., 4 figs., 1 tab.

Ishibashi, Masatoshi; Kumabe, Tsutomu; Morita, Seiichiro [Kurume Univ. School of Medicine (Japan)] [and others

1995-10-01

258

Structural and spatial determinants regulating TC21 activation by RasGRF family nucleotide exchange factors.  

PubMed

RasGRF family guanine nucleotide exchange factors (GEFs) promote guanosine diphosphate (GDP)/guanosine triphosphate (GTP) exchange on several Ras GTPases, including H-Ras and TC21. Although the mechanisms controlling RasGRF function as an H-Ras exchange factor are relatively well characterized, little is known about how TC21 activation is regulated. Here, we have studied the structural and spatial requirements involved in RasGRF 1/2 exchange activity on TC21. We show that RasGRF GEFs can activate TC21 in all of its sublocalizations except at the Golgi complex. We also demonstrate that TC21 susceptibility to activation by RasGRF GEFs depends on its posttranslational modifications: farnesylated TC21 can be activated by both RasGRF1 and RasGRF2, whereas geranylgeranylated TC21 is unresponsive to RasGRF2. Importantly, we show that RasGRF GEFs ability to catalyze exchange on farnesylated TC21 resides in its pleckstrin homology 1 domain, by a mechanism independent of localization and of its ability to associate to membranes. Finally, our data indicate that Cdc42-GDP can inhibit TC21 activation by RasGRF GEFs, demonstrating that Cdc42 negatively affects the functions of RasGRF GEFs irrespective of the GTPase being targeted. PMID:19692568

Calvo, Fernando; Crespo, Piero

2009-10-01

259

Characterization of the Generation of Radiolabeled Monodisperse Albuterol Particles Using the Spinning-Top Aerosol Generator  

Microsoft Academic Search

Inhaled radiolabeled aerosols provide invaluable information about in vivo drug deposition. Here, we report our methodology for radiolabeling and imaging monodisperse pharmacologic aerosols in order to study basic aerosol science concepts of drug delivery within the human airways. Methods: We used a spinning-top aerosol generator to produce 99mTc-labeled mono- disperse albuterol sulfate aerosols of 1.5-, 3-, and 6-m mass median

Omar S. Usmani; Martyn F. Biddiscombe; S. Richard Underwood; Peter J. Barnes

260

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

261

TC-100 solar-collector review program. Final report summary  

SciTech Connect

Field and laboratory tests, materials investigation and tests, and thermal modeling work were conducted to determine the extent and effect of serpentine oxidation on thermal performance of the TC-100 solar collector. This work included measurements at six field installations to determine the extent of atmospheric fin oxidation on typical solar collectors at each site. Thermal efficiency performance tests were conducted at the Gilroy Foods solar installation. Field performance tests conducted separately on the two essentially identically constructed halves of this solar collector installation which had experienced significantly different periods of stagnation, i.e., subjected to solar insolation without coolant flow. Laboratory tests were also performed to determine performance of solar collectors subjected to varying amount of stagnation. Laboratory tests were conducted to determine the atmospheric oxidation of copper serpentines at temperatures up to 750/sup 0/F. The oxidation of the copper fin was found to be dependent upon fin stagnation temperature, number of stagnation cycles and humidity. At temperatures below 300/sup 0/F atmospheric oxidation of the fin was negligible, at 750/sup 0/F it increased significantly. Low system thermal performance of the TC-100 collector cannot be attributed to fin oxidation alone. Worst case of oxidation reduced thermal performance of the collector by 2 to 3 percentage points; complete removal of the collector fins gave a reduction of 5 percentage points.

Darnell, A.J.; Marlatt, W.P.; Roberts, J.K.

1981-06-01

262

Application of superconductors to motors, generators, and transmission lines  

Microsoft Academic Search

Two specific applications of superconductors are considered: electric machinery (motors and generators) and transmission lines. Development work carried out with respect to both types of equipment indicates that the use of superconductors is feasible, even if only liquid-helium-cooled superconductors are considered. The high-Tc superconductors will have a beneficial impact on motors, generators, and transmission lines only if conductors with sufficient

James L. Kirtley; Frederick J. Edeskuty

1989-01-01

263

Evaluation of 99mTc-Mercaptoacetyltriglycine-Biocytin as a new hepatobiliary imaging agent in mice coinjected with bilirubin  

Microsoft Academic Search

We evaluated 99mTc-labeled mercaptoacetyltriglycine (99mTc-MAG3)-biocytin as a hepatobiliary imaging agent in the absence and presence of bilirubin in mice. We then compared its pharmacokinetic parameters; peak liver\\/heart activity ratio (rmax) and half clearance time (HCT) with those of 99mTc-labeled diisopropyl-iminodiacetic acid (99mTc-disofenin). Balb\\/c mice were injected intravenously with hepatobiliary agent (99mTc-MAG3-biocytin or 99mTc-disofenin) alone or in combination with bilirubin at

Meyoung-kon Kim; Jürgen Seidel; Nhat Le; In-Sook Kim; Tae-Moo Yoo; Craig Barker; Hisataka Kobayashi; Michael V Green; Jorge A Carrasquillo; Chang H Paik

1999-01-01

264

Determination of the 99Tc(thermal n,{gamma})100Tc Reaction Cross Section from the Prompt {gamma}-Ray Yields  

SciTech Connect

Analyses were made of the prompt {gamma} rays emitted in the thermal neutron capture reaction by 99Tc to determine the reaction cross section. From the obtained data, a partial decay scheme was constructed which consists of 88 {gamma} rays and 36 bound states. Six {gamma} rays were assigned as the transitions to the ground state of 100Tc. From the intensities of these six {gamma} rays, a lower limit of the reaction cross section was obtained to be 21.37 {+-} 0.68 b.Through a least-squares fit to the level energies, the neutron separation energy of 100Tc was determined as 6765.20 {+-} 0.04 keV.Gamma rays in 100Ru emitted following the {beta}- decay of the reaction product 100Tc were also analyzed. The inferred capture cross section is 22.8 {+-} 1.8 b.

Furutaka, Kazuyoshi; Harada, Hideo [Japan Nuclear Cycle Development Institute, Ibaraki 319-1194 (Japan); Raman, Subramanian [Oak Ridge National Laboratory, TN 37831 (United States)

2005-05-24

265

Extraction of arterial input function for measurement of brain perfusion index with 99mTc compounds using fuzzy clustering.  

PubMed

Cerebral blood flow (CBF) can be quantified non-invasively using the brain perfusion index (BPI) determined from radionuclide angiographic data generated with 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO). When measuring the BPI, manual drawing of regions of interest (ROIs) (manual ROI method) for the extraction of the arterial input function (AIF) can lead to serious individual differences. The purpose of this study was to apply the fuzzy c-means (FCM) clustering method to determine AIF, and to investigate its usefulness in comparison with the manual ROI method. Radionuclide angiography was performed using a bolus injection of about 555 MBq of 99mTc-HMPAO, followed by sequential imaging (1 sec/frame x 120 s) using a solid-state gamma camera, and the BPI values were calculated using spectral analysis. To investigate the dependence of BPI on the ROI size, we drew five ROIs with different sizes over the aortic arch, and calculated the BPI using the manual ROI method [BPI(manual)] and the FCM clustering method [BPI(FCM)]. Furthermore, we asked 10 individuals to draw ROIs to investigate the inter-operator variability of the two methods. The mean and standard deviation (SD) of BPI(manual) increased with increasing ROI size, whereas the mean of BPI(FCM) was almost constant regardless of the ROI size; the SD of BPI(FCM) was smaller than that of BPI(manual). The inter-operator variability of the FCM clustering method was smaller than that of the manual ROI method. These results suggest that the FCM clustering method appears to be useful for the measurement of BPI, because it allows a reliable and objective determination of AIF. PMID:15094450

Murase, Kenya; Nagayoshi, Makoto; Uenishi, Yusuke; Kawamata, Minoru; Yamazaki, Youichi; Takasawa, Masashi; Oku, Naohiko; Hatazawa, Jun

2004-03-01

266

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

267

Reductive sequestration of pertechnetate (??TcO??) by nano zerovalent iron (nZVI) transformed by abiotic sulfide.  

PubMed

Under anoxic conditions, soluble pertechnetate (??TcO??) can be reduced to less soluble TcO?·nH?O, but the oxide is highly susceptible to reoxidation. Here we investigate an alternative strategy for remediation of Tc-contaminated groundwater whereby sequestration as Tc sulfide is favored by sulfidic conditions stimulated by nano zerovalent iron (nZVI). nZVI was pre-exposed to increasing concentrations of sulfide in simulated Hanford groundwater for 24 h to mimic the onset of aquifer biotic sulfate reduction. Solid-phase characterizations of the sulfidated nZVI confirmed the formation of nanocrystalline FeS phases, but higher S/Fe ratios (>0.112) did not result in the formation of significantly more FeS. The kinetics of Tc sequestration by these materials showed faster Tc removal rates with increasing S/Fe between 0 and 0.056, but decreasing Tc removal rates with S/Fe > 0.224. The more favorable Tc removal kinetics at low S/Fe could be due to a higher affinity of TcO?? for FeS than iron oxides, and electron microscopy confirmed that the majority of the Tc was associated with FeS phases. The inhibition of Tc removal at high S/Fe appears to have been caused by excess HS(-). X-ray absorption spectroscopy revealed that as S/Fe increased, the pathway for Tc(IV) formation shifted from TcO?·nH2? to Tc sulfide phases. The most substantial change of Tc speciation occurred at low S/Fe, coinciding with the rapid increase in Tc removal rate. This agreement further confirms the importance of FeS in Tc sequestration. PMID:23611018

Fan, Dimin; Anitori, Roberto P; Tebo, Bradley M; Tratnyek, Paul G; Lezama Pacheco, Juan S; Kukkadapu, Ravi K; Engelhard, Mark H; Bowden, Mark E; Kovarik, Libor; Arey, Bruce W

2013-05-21

268

Reductive Sequestration Of Pertechnetate (99TcO4–) By Nano Zerovalent Iron (nZVI) Transformed By Abiotic Sulfide  

SciTech Connect

Under anoxic conditions, soluble 99TcO4– can be reduced to less soluble TcO2•nH2O, but the oxide is highly susceptible to reoxidation. Here we investigate an alternative strategy for remediation of Tc-contaminated groundwater whereby sequestration as Tc sulfide is favored by sulfidic conditions stimulated by nano zero-valent iron (nZVI). nZVI was pre-exposed to increasing concentrations of sulfide in simulated Hanford groundwater for 24 hrs to mimic the stages of aquifer sulfate reduction and onset of biotic sulfidogenesis. Solid-phase characterizations of the sulfidated nZVI confirmed the formation of nanocrystalline FeS phases, but higher S/Fe ratios (>0.112) did not result in the formation of significantly more FeS. The kinetics of Tc sequestration by these materials showed faster Tc removal rates with increasing S/Fe between S/Fe = 0–0.056, but decreasing Tc removal rates with S/Fe > 0.224. The more favorable Tc removal kinetics at low S/Fe could be due to a higher affinity of TcO4– for FeS (over iron oxides), and electron microscopy confirmed that the majority of the Tc was associated with FeS phases. The inhibition of Tc removal at high S/Fe appears to have been caused by excess HS–. X-ray absorption spectroscopy revealed that as S/Fe increased, Tc speciation shifted from TcO2•nH2O to TcS2. The most substantial change of Tc speciation occurred at low S/Fe, coinciding with the rapid increase of Tc removal rate. This agreement further confirms the importance of FeS in Tc sequestration.

Fan, Dimin; Anitori, Roberto; Tebo, Bradley M.; Tratnyek, Paul G.; Lezama Pacheco, Juan S.; Kukkadapu, Ravi K.; Engelhard, Mark H.; Bowden, Mark E.; Kovarik, Libor; Arey, Bruce W.

2013-04-24

269

TC1 (C8orf4) is upregulated by cellular stress and mediates heat shock response.  

PubMed

TC1 (C8orf4) is associated with aggressive behavior and poor survival in cancer. We have recently reported that it is a target gene of NF-kappaB and regulates the Wnt/beta-catenin pathway. Here, we show that TC1 is upregulated by various cellular stresses and mediates heat shock response. Heat shock and other cellular stresses including H2O2, 12-O-tetradecanoylphorbol 13-acetate (TPA), lipopolysaccharide (LPS), and UV enhance TC1 transcription in HeLa, KATO-III, HEK293T, and HK cells. TC1 protein then moves into the nuclei independently of NF-kappaB activation. TC1 upregulates heat shock proteins, and TC1-knockdown inhibits stress-induced downstream regulation significantly. Heat shock factor 1(HSF1) and TC1 upregulate each other, suggesting a potential positive feedback in the heat shock response regulation. Our data suggest that TC1 is a novel heat shock response regulator. PMID:17603013

Park, Juhee; Jung, Yusun; Kim, Jungtae; Kim, Ka-Young; Ahn, Sang-Gun; Song, Kyuyoung; Lee, Inchul

2007-08-24

270

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

271

Measurement of the Pressure Dependence of Tc for Superconducting Spinel Compounds.  

National Technical Information Service (NTIS)

The superconducting transition temperatures (Tc) of CuRh2Se4, CuRh2S4 and LiTi204 were all found to increase linearly under hydrostatic pressure up to 22kbar, at a rate of 1-5 x 10-5Kbar-1. These results are discussed in terms of the dependence of Tc on D...

R. N. Shelton D. C. Johnston H. Adrian

1976-01-01

272

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

273

Novel Approach to Prepare (sup 99m)Tc-Based Multivalent RGD Peptides.  

National Technical Information Service (NTIS)

This project presents a novel approach to prepare the (sup 99m)Tc-bridged multivalent RGD (arginine-glycine-aspartate) peptides. This project will focus on fundamentals of (sup 99m)Tc radiochemistry. The main objective of this project is to demonstrate th...

S. Liu

2012-01-01

274

The Thlaspi caerulescens NRAMP homologue TcNRAMP3 is capable of divalent cation transport.  

PubMed

The NRAMP gene family encodes integral membrane protein and mediates the transport of Fe, however, its function in transport of toxic metal ions is not very clear in plants. TcNRAMP3 was isolated from Thlaspi caerulescens, and encoded a metal transporter member of the NRAMP family. TcNRAMP3 was predominantly expressed in roots of T. caerulescens by semi-quantitative RT-PCR. The expression of TcNRAMP3 was induced by iron starvation and by the heavy metals Cd and Ni in roots. TcNRAMP3 was able to rescue growth of an iron uptake fet3fet4 mutant yeast strain, suggesting a possible role in iron transport. Expression of TcNRAMP3 in yeast increased Cd sensitivity and Cd content, while it enhanced the Ni resistance and reduced Ni accumulation, indicating that TcNRAMP3 could accumulate Cd and exclude Ni in yeast. Furthermore, overexpression of TcNRAMP3 in tobacco resulted in slight Cd sensitivity of root growth and did not influence Ni resistance. These results suggested that TcNRAMP3 played a role in metal cation homeostasis in plant. PMID:18663607

Wei, Wei; Chai, Tuanyao; Zhang, Yuxiu; Han, Lu; Xu, Jin; Guan, Ziqiu

2009-01-01

275

A relation between the charge density wave (CDW) instability and superconducting Tc in layered compounds  

Microsoft Academic Search

It is shown that the superconducting Tc of metallic layered compounds increases as the Charge Density Wave (CDW) is suppressed. Specifically, the magnitude of the change in magnetic susceptibility caused by the CDW is inversely related to Tc. The CDW can be suppressed by intercalation or substitution.

F. J. Di Salvo

1977-01-01

276

Localization of hemorrhage in a recurrent hemothorax using Tc-99m-sulfur colloid  

SciTech Connect

Tc99m-sulfur colloid scintigraphy has proven clinically useful in identifying gastrointestinal hemorrhages. The authors describe a patient with recurrent hemothorax under oral anticoagulation therapy in which Tc-99m-sulfur colloid imaging was used to determine the site of bleeding.

Taillefer, R.; Essiambre, R.; Lemieux, R.

1981-05-01

277

Chemistry and Biology of Tc-99M Renal Function Agents. Final Report.  

National Technical Information Service (NTIS)

A major aim of the project was to develop a Tc-99m renal tubular function radiopharmaceutical. Progress was made in synthesizing and evaluating Tc-99m 2,3-dimercaptoaceta-midoprepanoate (CO sub 2 DADS). In animals and clinical studies the A epimer (early ...

A. M. Fritzberg

1986-01-01

278

Vicarious visualization of gall bladder on Tc-99m ethylene dicysteine renal dynamic study.  

PubMed

Though the hepatobiliary excretion of Technetium-99m ethylene dicysteine (99mTc-EC) is very low and usually does not effect image interpretation on routine posterior imaging, the possibility of visualization of the gall bladder should be kept in mind while reporting the 99mTc-EC scan especially, when anterior imaging is performed as in renal transplant patients. PMID:24019659

Arora, Geetanjali; Damle, Nishikant A; Tripathi, Madhavi; Bal, Chandrasekhar; Kumar, Praveen

2012-10-01

279

Vicarious visualization of gall bladder on Tc-99m ethylene dicysteine renal dynamic study  

PubMed Central

Though the hepatobiliary excretion of Technetium-99m ethylene dicysteine (99mTc-EC) is very low and usually does not effect image interpretation on routine posterior imaging, the possibility of visualization of the gall bladder should be kept in mind while reporting the 99mTc-EC scan especially, when anterior imaging is performed as in renal transplant patients.

Arora, Geetanjali; Damle, Nishikant A; Tripathi, Madhavi; Bal, Chandrasekhar; Kumar, Praveen

2012-01-01

280

Heterogeneous Reduction of Tc(VII) by Fe(II) at the Solid-Water Interface  

SciTech Connect

Technetium-99 is a byproduct of uranium fission. It exists in two stable valence states (IV/VII) and exhibits a half-cell potential of intermediate value (Eo = 0.748 V). The oxidized form of 99Tc [pertechnetate, TcO4-] is an oxyanion that sorbs poorly to amphoteric surfaces and forms few solid phases with geochemically relevant cations. It is consequently highly mobile in oxic water-rock systems. The reduced valence state [Tc(IV)] is relatively insoluble (<10-8 mol L-1), and, hence immobile as an oxyhydroxide precipitate [TcO2•nH2O(s)]. In spite of favorable thermodynamics, Tc(VII) reacts slowly with Fe2+(aq) under anoxic conditions. Experiments were performed herein to investigate the rates and products of heterogeneous reduction of Tc(VII) by Fe(II) sorbed to hematite and goethite, and by structural Fe(II) in a dithionite-citrate-bicarbonate (DCB) reduced natural phyllosilicate mixture containing vermiculite, illite, and muscovite. The heterogeneous reduction of Tc(VII) by Fe(II) sorbed to the Fe(III) oxides increased with increasing pH and was coincident with a second event of Fe2+(aq) adsorption. The reaction was almost instantaneous above pH 7. In contrast, the reduction rates of Tc(VII) by structural Fe(II) in the DCB-reduced phyllollsilicates, were not sensitive to pH or the concentration of ion-exchangeable Fe(II), and were orders of magnitude slower than observed for the Fe(III) oxides. Tc-EXAFS spectroscopy revealed that the reduction products were virtually identical on hematite and goethite that were comprised primarily of sorbed octahedral TcO2 monomers and dimers with significant Fe(III) in the second coordination shell. The nature of heterogeneous Fe(III) resulting from the redox reaction was ambiguous as probed by Tc-EXAFS spectroscopy, although Mössbauer spectroscopy applied to an experiment with 56Fe-goethite with adsorbed 57Fe(II) implied that redox product Fe(III) was goethite-like. The Tc(IV) reduction product formed on the DCB-reduced phyllosilicates was different from the Fe(III) oxides, and was more similar to Tc(IV) oxyhydroxide in its second coordination shell. The heterogeneous reduction of Tc(VII) to less soluble forms by sorbed and structural Fe(II) in anoxic environments may be a very important geochemical process that will proceed at very different rates and that will yield different surface species depending subsurface pH and mineralogy.

Peretyazhko, Tetyana; Zachara, John M.; Heald, Steve M.; Jeon, Byong Hun; Kukkadapu, Ravi K.; Liu, Chongxuan; Moore, Dean A.; Resch, Charles T.

2008-03-15

281

Enhancement of Tc in HgBa2Ca2Cu3O8+? by fluorination  

NASA Astrophysics Data System (ADS)

A 4 K increase of Tc in Hg-1223 was achieved by the exchange with fluorine of the extra oxygen located in (HgO?) layer. Fluorination of the initially reduced Hg-1223 samples with Tc~=100 K by XeF2 results in the increase of Tc up to 138 K while treatment in oxygen flow causes the enhancement of Tc not higher than up to 134 K. From x-ray and neutron diffraction data we conclude that shortening of the in-plane Cu-O distances without significant (CuO2) layers buckling in fluorinated Hg-1223 seems to be the main structural factor responsible for the enhancement of Tc.

Lokshin, K. A.; Pavlov, D. A.; Putilin, S. N.; Antipov, E. V.; Sheptyakov, D. V.; Balagurov, A. M.

2001-02-01

282

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

283

Passport, a native Tc1 transposon from flatfish, is functionally active in vertebrate cells  

PubMed Central

The Tc1/mariner family of DNA transposons is widespread across fungal, plant and animal kingdoms, and thought to contribute to the evolution of their host genomes. To date, an active Tc1 transposon has not been identified within the native genome of a vertebrate. We demonstrate that Passport, a native transposon isolated from a fish (Pleuronectes platessa), is active in a variety of vertebrate cells. In transposition assays, we found that the Passport transposon system improved stable cellular transgenesis by 40-fold, has an apparent preference for insertion into genes, and is subject to overproduction inhibition like other Tc1 elements. Passport represents the first vertebrate Tc1 element described as both natively intact and functionally active, and given its restricted phylogenetic distribution, may be contemporaneously active. The Passport transposon system thus complements the available genetic tools for the manipulation of vertebrate genomes, and may provide a unique system for studying the infiltration of vertebrate genomes by Tc1 elements.

Clark, Karl J.; Carlson, Daniel F.; Leaver, Michael J.; Foster, Linda K.; Fahrenkrug, Scott C.

2009-01-01

284

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 âdissipation-lessâ technologies is that we lack a comprehensive perception of all the mechanisms which govern high-Tc superconductivity. Controversial in nature, âcharge stripingâ 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

285

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

286

Chemical compatibility of high-Tc superconductors with other materials  

NASA Astrophysics Data System (ADS)

In any application, the new oxide superconductors will have to coexist in intimate contact with other materials. However, the copper oxygen bonds common to all presently known oxide superconductors with Tc above 40K are relatively weak. This means that elements that form much stronger bonds with oxygen, such as Si, will be chemically unstable when in contact with the copper-oxide superconductors. In this paper, we will establish procedures and guidelines that will enable workers to choose materials that will not react chemically with the oxide superconductors. These should enable researchers working in all applications areas to avoid unnecessary empirical searches for suitable substrate or host materials by eliminating the most thermodynamically unfavorable choices. In particular, we have determined which of the elemental metals should be most stable in contact with the copper-oxide semiconductors, and examined schemes for integrating these superconductors into Si devices.

Williams, R. S.; Chaudhury, S.

1988-07-01

287

On the Theory of the HIGH-TcSUPERCONDUCTING Materials  

NASA Astrophysics Data System (ADS)

Methods are described which can be used for an analytical description of the strong electron correlations in the planes of the Cu-O based high-Tc superconducting materials. One is a projection technique which is applied in order to calculate the photoelectron and inverse photoelectron spectra for the cases of half filling and hole doping of the Cu-O planes. Good agreement with the results of exact diagonalization of (CuO2)4 clusters is obtained, proving the usefulness of the method. Another one is the concept of string states which can be applied to study the t-J model. Also in this case a number of numerical findings can be reproduced and improved by this analytic method.

Fulde, Peter

288

Vent Flowing Cold Gas and T/C Rake  

NASA Technical Reports Server (NTRS)

Vent flowing cryogenic fuel and T/C Rake mounted on a 1/10 scale model Centaur in the l0 x l0 Foot Supersonic Wind Tunnel. The fuel being used is liquid hydrogen. The point of the test is to determine how far to expel venting fuel from the rocket body to prevent explosion at the base of the vehicle. This vent is used as a safety valve for the fumes created when loading the fuel tanks during launch preparation. Liquid hydrogen has to be kept at a very low temperature. As it heats, it turns to gas and increases pressure in the tank. It therefore has to be vented overboard while the rocket sits on the pad. The test is being run at the Lewis Research Center, now known as John H. Glenn Research Center, Lewis Field.

1963-01-01

289

Modified gradiometer technique applied to Double Star (TC-1)  

NASA Astrophysics Data System (ADS)

On TC-1 (Tan Ce 1), the equatorial spacecraft of the Double Star mission, a strong spin-synchronized magnetic interference from the solar panels was observed. In-flight correction techniques for spinning spacecraft that are based on minimizing spin tones in the spin-aligned component and in the magnitude of the ambient magnetic field are therefore not possible in this case. However, due to the fortunate situation that the spacecraft carries two flux-gate magnetometers on the same boom (at 0.5 m distance from each other), the spacecraft field effects could be removed from the spin-averaged data to achieve 0.2 nT relative accuracy, by using a gradiometer technique. Methodology and results are presented. The obtained accuracy allows the use of the data in multi-spacecraft studies together with the Cluster satellites.

Georgescu, E.; Auster, H. U.; Takada, T.; Gloag, J.; Eichelberger, H.; Fornaçon, K.-H.; Brown, P.; Carr, C. M.; Zhang, T. L.

290

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

291

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

292

Wind Generators  

NASA Technical Reports Server (NTRS)

When Enerpro, Inc. president, Frank J. Bourbeau, attempted to file a patent on a system for synchronizing a wind generator to the electric utility grid, he discovered Marshall Space Flight Center's Frank Nola's power factor controller. Bourbeau advanced the technology and received a NASA license and a patent for his Auto Synchronous Controller (ASC). The ASC reduces generator "inrush current," which occurs when large generators are abruptly brought on line. It controls voltage so the generator is smoothly connected to the utility grid when it reaches its synchronous speed, protecting the components from inrush current damage. Generator efficiency is also increased in light winds by applying lower than rated voltage. Wind energy is utilized to drive turbines to generate electricity for utility companies.

1989-01-01

293

Pattern generation.  

PubMed

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 of generator operation in behaviorally relevant contexts. Recently, it has been shown that the high reliability and flexibility of central pattern generators is determined by their redundant organization. Everything that is crucial for generator operation is determined by a number of complementary mechanisms acting in concert; however, various mechanisms are weighted differently in determining different aspects of central pattern generator operation. PMID:9464971

Arshavsky, Y I; Deliagina, T G; Orlovsky, G N

1997-12-01

294

Synopsis of French experimental and in situ research on the terrestrial and marine behavior of Tc  

SciTech Connect

Terrestrial environment studies have been essentially concerned with the evolution of soil deposition and soil-plant transfers. Experimentally determined coefficients of distribution in soils are low: 60-80% of Tc remains hydrosoluble during the first months. Technetium emissions resulting from microbiological activity have been quantified. Antagonistic effects on Mo and Tc retention by soils are dependent on their respective concentrations. Four areas of soil-plant transfers have been studied: (1) root absorption kinetics relative to deposition of Tc, (2) interaction of stable Mo (environmental parameter) with the transfer of Tc to plants, (3) interaction of some long-lived radioisotopes (effluent parameters) with the transfer of Tc to plants, and (4) long-term soil-plant transfer and aging of deposited material. Of aquatic systems, only the marine environment has been studied. Under anoxic conditions in the presence of reducing sediments, the distribution coefficients (Kd) were very high (10(3)). Concentration factors (CF) from water to organisms were generally very low (1 to 10); however, CF greater than 1000 have been observed for some biota such as macrophytic brown algae, worms and lobsters. Biochemical analysis showed that Tc was essentially free and partially bonded to proteins. The transfer factors between sediments and species were very low (TF less than 0.5). The biological half-time was determined in some marine organisms that had accumulated Tc from water, food or sediments; the loss is biphasic. Uptake in edible parts was low. The physiochemical form affects the accumulation and loss of Tc. Analyses have quantified 99Tc in marine fauna and biota in the English Channel in relation with releases of the reprocessing plant of La Hague. Brown algae are the best bioindicators for following 99Tc dispersion in marine ecosystems. 24 references.

Masson, M.; Patti, F.; Colle, C.; Roucoux, P.; Grauby, A.; Saas, A. (Laboratoire de Radioecologie Marine, Cherbourg (France))

1989-08-01

295

Bioaccumulation and distribution of /sup 95m/Tc in an experimental freshwater pond  

SciTech Connect

An acute release of /sup 95m/Tc was made to a small experimental freshwater pond to determine the behavior of technetium in a freshwater ecosystem. The objectives of the study were (1) to determine the distribution of /sup 95m/Tc in the components of the ecosystem and (2) to determine the concentration in freshwater biota. Prior to the release of /sup 95m/Tc, the pond was stocked with aquatic macrophytes, fish, and invertebrates. All components of the pond were sampled for a period of 37 d. Analyses of filtered and unfiltered water samples showed that /sup 95m/Tc did not sorb significantly to particulates suspended in the water but remained dissolved. Sediments accumulated /sup 95m/Tc slowly as the experiment progressed. In the biota, periphyton accumulated /sup 95m/Tc rapidly, reaching the highest concentration (3482 dpm/g dry wt) 4 h after the release and maintaining a relatively high concentration throughout the experiment. Fish and invertebrates accumulated /sup 95m/Tc gradually. Elimination studies and tissue analyses showed that a large percentage of the body burden was in the digestive system of all fish, suggesting that fish were accumulating /sup 95m/Tc through the food chain. Biological half-lives determined from elimination studies for carp (Cyprinus carpio), mosquitofish (Gambusia affinis), and snails (Helisoma sp.) were 2.5, 4.3, and 21.3 d, respectively. Calculated concentration factors for the same species were 11 for carp, 75 for mosquito fish, and 121 for snails. The estimated size of the biomass components in the ecosystem in descending order were: periphyton, macrophytes, invertebrates, fish, and algae. Based on biomass estimates and concentrations of the /sup 95m/Tc in the aquatic biota, approximately 1% of the /sup 95m/Tc accumulated in the biota.

Blaylock, B.G.; Frank, M.L.

1981-01-01

296

Astrocytes as a predominant cellular site of (99m)Tc-HMPAO retention.  

PubMed

Technetium-99m-d,l-hexamethylpropylene amine oxime ((99m)Tc-HMPAO) retention in the brain monitored by single photon emission computed tomography (SPECT) is currently used as a marker of cerebral blood flow. The purported mechanism by which (99m)Tc-HMPAO accumulates in the brain is through its intracellular conversion from a lipophilic form to more hydrophilic derivatives within the brain parenchyma. The issue of the contribution of different cell types on (99m)Tc-HMPAO retention was investigated in vitro by studying the accumulation of (99m)Tc-HMPAO in primary cultures of mouse cortical astrocytes and neurons. Results show that (99m)Tc-HMPAO retention predominates in astrocytes over neurons by a factor of approximately 2.5 (0.26 +/- 0.05 vs. 0.095 +/- 0.042 fmol/mg protein after 120 minutes, respectively). Diethyl maleate (60 micromol/L), ethacrynic acid (1 mmol/L) and buthionine sulfoximine (1 mmol/L), 3 agents which significantly reduced glutathione levels also decreased (99m)Tc-HMPAO retention in both astrocytes (29%, 3%, and 46% of control, respectively) and neurons (69%, 11% and 63% of control). Decrease did not always correlate with glutathione levels, however, which suggests that other factors could be involved. The possibility that cell energy status determines (99m)Tc-HMPAO retention was also assessed. Agents that activate (glutamate, azide) or inhibit (cytochalasin B) glucose utilization in astrocytes, as measured by the (3)H-2-deoxyglucose method, were without effect on (99m)Tc-HMPAO retention. In conclusion, the data presented indicate that astrocytes may constitute a prominent site of (99m)Tc-HMPAO retention and most likely contribute significantly to the SPECT signal. In addition, the data also suggest that specific alterations in glial cell metabolism could explain flow-independent changes in (99m)Tc-HMPAO retention in the brain as observed by SPECT in some pathologies. PMID:11323531

Zerarka, S; Pellerin, L; Slosman, D; Magistretti, P J

2001-04-01

297

Kinetics of 99mTc-labeled pyrophosphate and polyphosphate in man.  

PubMed

Thekinetic of 99mTc-labeled pyrophosphate were compared with those of polyphosphate in ten patients in a combined study. Both agents cleared from the blood in a biexpoential fashion. The clearance half-time of Exponent I was the same for both and was shorter than the clearance half-time of Exponent ii. Urinary excretion of both agents was the same during the first hour but during the next 3 hr Tc-pyrophosphate cleared at a slightly more rapid rate, resulting in lower blood background radioactivity. Both agents were bound loosely to plasma proteins, mainly to globulin fractions. The sensitivity of lesion detection was similar for both. Excellent bone images were obtained with both agents. The images with Tc-pyrophosphatewere consistently superior owing to the low blood background and they took less time to accumulate an identical number of counts from identical regions. With the amount of 99mTc-complex used, no hyocalcemia or tetany was noted, nor was there any significant effect on 1-hr serum levels of inorganic phosphours and alkaline phosphatase. Four hours after injection, 9.5% of the dose of Tc-pyrophosphate was circulating in blood, 31.7% was excreted in urine, and the remaining 58.8% was taken up by bone and other tissues. The corresponding values with Tc-polyphosphate were 12.5% in blood, 29.0% in urine, and 58.5% in bone and other tissues. Among the soft tissues, the genitourinary system is most consistently visualized. It is concluded that both Tc-pyroposphate and Tc-polyphosphate are excellent skeletal-imaging agents and that Tc-pyrophosphate appears slightly superior to Tc-polyphosphate. PMID:162949

Krishnamurthy, G T; Huebotter, R J; Walsh, C F; Taylor, J R; Kehr, M D; Tubis, M; Blahd, W H

1975-02-01

298

Distribution of Orally Administered and Chronically Fed /Sup 95M/Tc in Japanese Quail Tissues and Eggs.  

National Technical Information Service (NTIS)

Previous coefficients for transfer of technetium from feed to poultry have utilized default values. These investigations examined the uptake and distribution of /sup 95m/Tc in male and female Japanese quail following their ingestion of Tc incorporated int...

J. M. Thomas L. L. Cadwell T. R. Garland D. A. Cataldo

1984-01-01

299

Ascophyllan Purified from Ascophyllum nodosum Induces Th1 and Tc1 Immune Responses by Promoting Dendritic Cell Maturation  

PubMed Central

Marine-derived sulfated polysaccharides have been shown to possess certain anti-virus, anti-tumor, anti-inflammatory and anti-coagulant activities. However, the in vivo immunomodulatory effects of marine-derived pure compounds have been less well characterized. In this study, we investigated the effect of ascophyllan, a sulfated polysaccharide purified from Ascophyllum nodosum, on the maturation of mouse dendritic cells (DCs) in vitro and in vivo. Ascophyllan induced up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in bone marrow-derived DCs (BMDCs). Moreover, in vivo administration of ascophyllan promotes up-regulation of CD40, CD80, CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-? in spleen cDCs. Interestingly, ascophyllan induced a higher degree of co-stimulatory molecule up-regulation and pro-inflammatory cytokine production than fucoidan, a marine-derived polysaccharide with well-defined effect for promoting DC maturation. Ascophyllan also promoted the generation of IFN-?-producing Th1 and Tc1 cells in the presence of DCs in an IL-12-dependent manner. Finally, myeloid differentiation primary response 88 (MyD88) signaling pathway was essential for DC maturation induced by ascophyllan. Taken together, these results demonstrate that ascophyllan induces DC maturation, and consequently enhances Th1 and Tc1 responses in vivo. This knowledge could facilitate the development of novel therapeutic strategies to combat infectious diseases and cancer.

Zhang, Wei; Du, Jiang-Yuan; Jiang, Zedong; Okimura, Takasi; Oda, Tatsuya; Yu, Qing; Jin, Jun-O

2014-01-01

300

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

2012-12-01

301

Intravenous aminohydroxypropylidene bisphosphonate does not modify 99mTc-hydroxymethylene bisphosphonate bone scintigraphy. A prospective study.  

PubMed

Bisphosphonates have marked affinity for bone that makes them useful in both the treatment and imaging of bone lesions. Bone scintigraphy is very sensitive for the detection of bone metastases, which can cause life-threatening hypercalcemia requiring emergency treatment. This prospective study was done to determine whether intravenous administration of pamidronate, a second-generation bisphosphonate used to treat hypercalcemia, affects the affinity of the radiopharmaceutical 99m technetium-labeled hydroxymethylene bisphosphonate (99mTc-HMDP) for bone and bone lesions. Six patients with metastatic bone disease and five with Paget's disease of bone had a 99mTc-HMDP bone scan before and two to four days after an intravenous infusion of pamidronate. The number and activity of metastatic bone lesions were unchanged after pamidronate, even when the second bone scan was done only 24 hours after the pamidronate infusion. Our data suggest that emergency treatment of life-threatening hypercalcemia by intravenous pamidronate does not decrease the sensitivity of subsequent bone scanning done to detect bone metastases. PMID:7600079

Macro, M; Bouvard, G; Le Gangneux, E; Colin, T; Loyau, G

1995-02-01

302

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

303

Radionuclide imaging in myocardial sarcoidosis. Demonstration of myocardial uptake of /sup 99m/Tc pyrophosphate and gallium  

SciTech Connect

A patient had severe congestive cardiomyopathy secondary to myocardial sarcoidosis. The clinical diagnosis was confirmed by radionuclide ventriculography, /sup 201/Tl, /sup 67/Ga, and /sup 99m/Tc pyrophosphate (TcPYP) scintigraphy. Myocardial TcPYP uptake has not been reported previously in sarcoidosis. In this patient, TcPYP was as useful as gallium scanning and thallium imaging in documenting the myocardial process.

Forman, M.B.; Sandler, M.P.; Sacks, G.A.; Kronenberg, M.W.; Powers, T.A.

1983-03-01

304

Technetium bis(. mu. -oxo) dimers of 1,4,7-triazacyclononane-N,N prime N, double prime -triacetate (TCTA). Synthesis and characterization of (TCTA)Tc(. mu. -O) sub 2 Tc(TCTA) sup n- (n = 2,3) and the crystal structure of Ba sub 2 (TCTA)Tc(. mu. -O) sub 2 Tc(TCTA)(ClO sub 4 )ter dot 9H sub 2 O  

SciTech Connect

The mixed-valence technetium(III/IV) bis({mu}-oxo) dimer ((TCTA)Tc({mu}-O){sub 2}Tc(TCTA)){sup 3{minus}} (1; TCTA = 1,4,7-triazayclononane-N,N{prime},N{double prime}-triacetate) has been prepared as its sodium and barium salts. This complex undergoes a reversible on-electron oxidation with potassium persulfate to form ((TCTA)Tc({mu}-O){sub 2}Tc(TCTA)){sup 2{minus}} (2). Both complexes have been characterized by elemental analysis, infrared, UV/visible, and resonance Raman spectroscopy, and fast atom bombardment mass spectrometry. A crystal structure analysis of the Tc(III/IV) dimeter Ba{sub 2}((TCTA)Tc({mu}O){sub 2}Tc(TCTA))(ClO{sub 4}){center dot}9H{sub 2}O (1c) reveals that the two Tc atoms are linked by a planar Tc({mu}-O){sub 2}Tc ring. One TCTA ligand binds to each Tc through an N{sub 3}O donor set, and one of the acetate groups from each ligand bridges the two metal atoms. Resonance Raman spectra of complexes 1 and 2 were obtained by irradiation at 514.5 nm; strong bands assigned to the four-membered Tc({mu}-O){sub 2}Tc ring and the metal-metal multiple bond were seen. The aqueous electrochemistry of the compounds confirms that they are related by a reversible one-electron wave. The Tc(III/IV) dimer 1 represents the first fully characterized Tc-(amino carboxylate) complex in an oxidation state lower than +4. Evidence for the existence of other Tc(III/IV) bis({mu}-oxo) dimers of this type with amino carboxylate ligands such as EDTA and NTA is presented. 23 refs., 3 figs., 4 tabs.

Linder, K.E.; Dewan, J.C.; Davison, A. (Massachusetts Institute of Technology, Cambridge (USA))

1989-10-04

305

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

306

MO Tripeptide Diastereomers (M = 99/99mTc, Re): Models To Identify the Structure of 99mTc Peptide Targeted Radiopharmaceuticals  

PubMed Central

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 ~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 ~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.

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

2007-01-01

307

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

308

Piezoelectrostatic Generator  

NASA Technical Reports Server (NTRS)

High voltage generated by compact, lightweight equipment. Improved variable-capacitance electrostatic generator relies on piezoelectric effort to convert mechanical energy directly into electrical energy and contains neither transformers nor bulky high-voltage rectifiers. Requires neither external power supply to charge, nor vacuum to insulate electrodes.

Robertson, Glen A.

1989-01-01

309

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

310

Mapping lymph nodes in cancer management - role of 99mTc-tilmanocept injection  

PubMed Central

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. 99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, 99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of 99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, 99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing 99mTc-tilmanocept with other 99mTc-based agents are required before it can be routinely used in clinical settings.

Tausch, Christoph; Baege, Astrid; Rageth, Christoph

2014-01-01

311

Clinical Evaluation of Efficacy of 99mTC -Ethambutol in Tubercular Lesion Imaging  

PubMed Central

Purpose. The aim of this work was to develop specific radiopharmaceutical and to evaluate its efficacy in human to detect and locate the tubercular lesion. Materials and Methods. 99mTc-Ethambutol (EMB) was produced by direct labeling method. In vitro and in vivo biological studies and animal experiments were done. Phase I Clinical trial was performed. As per plan, 2 normal human subjects for biodistribution studies and fourteen patients (8 males and 6 females; age range of 25–50, with one patient aged 12 years as an exception) were chosen for clinical trial. Whole body scan and spots were acquired at 1 hour and 4 hour. Angiography, blood pool, and 24-hours spot images of the infected areas were also acquired. Result. Radiolabeling yielded >85% of labeled complex. In vitro and in vivo biological studies and animal experiments indicated 99mTc-EMB as a specific tuberculosis imaging agent. The biodistribution study in normal human subjects suggested stability of 99mTc-EMB, with main excretory pathways being renal and hepatobiliary, which appeared to be similar to the known behavior of unlabeled EMB. No adverse reactions were observed. 99mTc-EMB got localized in pulmonary and bone tubercular lesions. Scintigrams of 99mTc-EMB and 99mTc-Ciprofloxacin were compared at different time intervals. Conclusion. The present study states that developed 99mTc-EMB has high potential to qualify as a specific tuberculosis imaging radiopharmaceutical and is safe for human use.

Singh, Namrata; Bhatnagar, A.

2010-01-01

312

Imaging of primary and regionally metastatic lung cancer with Tc-99m SESTAMIBI  

SciTech Connect

The significance of pulmonary, hilar, and mediastinal uptake of Tc-99m SESTAMIBI in patients undergoing myocardial perfusion imaging was retrospectively investigated. SPECT myocardial perfusion images for 34 adult patients (ages: 52-to-82 years) with known lung cancer undergoing preoperative assessment of cardiac status and 29 {open_quotes}control{close_quotes} patients with normal chest radiographs and no history of lung cancer were reviewed. For the 29 patients without lung cancer there was no abnormal pulmonary, hilar, or mediastinal uptake of Tc-99m SESTAMIBI. For the 34 patients with histologically proven lung cancer, Tc-99m SESTAMIBI uptake was detected in 27 of 34 primary pulmonary lesions (79% sensitivity), 2 of 4 surgically proven hilar metastases, and 1 of 4 mediastinal metastases. The smallest lesion detected was 1.0 cm in diameter and the largest lesion not detected was 5.5 cm in diameter. For squamous cell carcinoma, 20 of 22 primary lesions were detected (91% sensitivity). Tc-99m SESTAMIBI detected 5 of 34 primary pulmonary lesions, 2 of 4 hilar metasteses, and 1 of 4 mediastinal metastases not identified by conventional chest radiographs. CT was superior to Tc-99m SESTAMIBI for detection of primary pulmonary lesions and was similar to Tc-99m SESTAMIBI in the limited number of cases with hilar and mediastinal metastatic involvement. We conclude that abnormal pulmonary, hilar, or mediastinal uptake of Tc-99m SESTAMIBI may be a clinically significant finding which should be correlated with chest radiography or CT.

Akansel, G.; Liu, Y.; Uygur, G.A. [Medical College of Wisconsin, Milwaukee, WI (United States)] [and others

1994-05-01

313

Electron-transfer reactions of technetium complexes. 1. Rate of the self-exchange reaction of the Tc(I)/Tc(II) couple (Tc(DMPE)/sub 3//sup +/2+/, where DMPE = 1,2-bis(dimethylphosphino)ethane  

SciTech Connect

The rate of the self-exchange electron-transfer reaction between (Tc(DMPE)/sub 3/)/sup +/ and (Tc(DMPE)/sub 3/)/sup 2 +/ has been determined by two independent applications of the Marcus theory. The rates and equilibrium constants governing the cross-reactions between (Tc(DMPE)/sub 3/)/sup +/2+/ and ((NH/sub 3/)/sub 5/RuL)/sup 2+/3+ (L = isonicotinamide, pyridine, 4-picoline) were measured in aqueous LiCl/HCl solutions. The known self-exchange rate of ((NH/sub 3/)/sub 5/Ru(py))/sup2+/3+/ was then used within the Marcus cross relationship to calculate three values of k/sub ex/ for (Tc(DMPE)/sub 3/)/sup =/2+/. These values fall within the range (0.8-4.0) x 10/sup 6/ M/sup -1/ s/sup -1/ (25 /sup 0/C, ..mu.. = 0.10 M). Estimated activation parameters for this reaction are ..delta..H/sub ex//sup */ = 7 +/- 3 kcal/mol and ..delta..S/sub ex//sup */ = -8 +/- 4 eu. Available bond length data show that, because of extensive ..pi..-back-bonding from Tc to P, the Tc-P bond expands by about 0.068 A upon oxidation of the technetium center. This information combined with estimates for the radius of the complex (4.8 A) and for the force constant of the Tc-P bond (1.64 x 10/sup 5/ dyn/cm), can be used within the Marcus formalism to calculate k/sub ex/. The resulting calculated value is 3 x 10/sup 6/ M/sup -1/ s/sup -1/ (25/sup 0/C), in excellent agreement with the median value determined kinetically. This agreement between kinetically and structurally determined values of k/sub ex/ demonstrates that the self-exchange reaction of the extensively ..pi..-back-bonded (Tc(DMPE)/sub 3/)/sup +/2+ system is adequately described within the Marcus formalism. Moreover, the value of k/sub ex/ for this d/sup 6//d/sup 5/ couple is in good agreement with the value of k/sub ex/ (2.2 x 10/sup 6/ M/sup -1/ s/sup -1/; 25/sup 0/X, ..mu.. = 0.10 M) observed for ((NH/sub 3/)/sub 4/Ru(bpy))/sup 2+/3+/, a predominantly sigma-bonded d/sup 6//d/sup 5/ couple of similar radius (4.4 A).

Doyle, M.N.; Libson, K.; Woods, M.; Sullivan, J.C.; Deutsch, E.

1986-09-10

314

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

2014-05-01

315

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

316

A (99m) Tc(CO)3 -labeled benzylguanidine with persistent heart uptake.  

PubMed

We describe the synthesis and biological evaluation of the cationic (99m) Tc-tricarbonyl complex fac-[(99m) Tc(CO)3 (?(3) -L1)](+) (Tc1) anchored by a pyrazole-diamine-methylbenzylguanidine-based ligand (L1), as potentially useful for myocardial imaging. The rhenium complex fac-[Re(CO)3 (?(3) -L1)](+) (Re1) was prepared and characterized as a 'cold' surrogate of the radioactive complex. Cell uptake studies in a neuroblastoma cell line suggest that Tc1 uptake mechanism is related to the norepinephrine transporter (NET). Tissue distribution studies in CD1 mice showed that Tc1 presents high initial heart uptake and a slow washout from the heart (7.8?±?1.3% injected dose per gram (ID/g), 30-min post-injection (p.i.); 6.3?±?1.3% ID/g, 60-min p.i.), with heart to blood ratios of 11.8 and 9.0 at 30- and 60-min p.i., respectively. The uptake mechanism of Tc1 appears to be similar to that of metaiodobenzylguanidine (MIBG), as it can be reduced by coinjection with nonradioactive MIBG. The biodistribution profile of Tc2, where the benzylguanidine pharmacophore is absent, corroborates the fact that Tc1 does not accumulate in the heart by a simple diffusion mechanism but rather by a NET-mediated mechanism. The results confirm those obtained in the cell assays. Despite the persistent heart uptake found for Tc1, the high hepatic and renal uptake remains to be improved. PMID:24861983

Oliveira, Bruno L; Morais, Maurício; Gano, Lurdes; Santos, Isabel; Correia, João D G

2014-05-15

317

The activation of TC10, a Rho small GTPase, contributes to v-Rel-mediated transformation.  

PubMed

v-Rel is the oncogenic member of the Rel/NF-kappaB 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 v-Rel-transformed chicken embryonic fibroblasts (CEFs) 3 to 6-fold relative to control cells at both the RNA and protein levels. An elevated level of active, GTP-bound TC10 was also detected in v-Rel-transformed cells relative to control cells. Expression of a dominant-negative TC10 mutant (TC10T32N) decreased the colony formation potential of v-Rel-transformed cells. Furthermore, overexpression of wild-type TC10 or a gain-of-function mutant (TC10Q76L) greatly enhanced the ability of v-Rel transformed CEFs to form colonies in soft agar. In addition to enhance the transformation potential of v-Rel, the overexpression of wild-type TC10 or the gain-of-function mutant alone enhanced the saturation density of CEFs and was sufficient for their anchorage-independent growth in vitro. These results indicate that elevated TC10 activity contributes to v-Rel-mediated transformation of CEFs and demonstrate for the first time that a Rho factor alone is capable of inducing the in vitro transformation of primary cells. PMID:17016434

Tong, S; Liss, A S; You, M; Bose, H R

2007-04-01

318

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

319

Assessment of Therapeutic Tumor Response Using 99m Tc-Ethylenedicysteine-Glucosamine  

Microsoft Academic Search

Purpose: The aim of this study was to evaluate 99mTc-ethylenedicysteine-glucosamine (EC-DG) for the assessment of tumor growth. Method: To evaluate whether 99mTc-EC-DG is involved in cell nuclei ac- tivity, in vitro thymidine incorporation, and cell-cycle assays of EC-DG were conducted using lung and breast cancer cells. Biodistribution of 99mTc-EC-DG in lung tumor-bearing mice (0.5-4 hours, 1 ? Ci\\/mouse, i.v.) was

David Yang; Masashi Yukihiro; Dong-Fang Yu; Megumi Ito; Chang-Sok Oh; Saady Kohanim; Ali Azhdarinia; Chang-Guhn Kim; Jerry Bryant; E. Edmund Kim; Donald Podoloff

2004-01-01

320

Distribution of Tc-99m administered as labeled microspheres for lung imaging  

SciTech Connect

We have measured the distribution of Tc-99m in 36 patients receiving labeled microspheres for routine lung imaging studies. Quantitative organ measurements were made by conjugate counting with an Anger camera at various times for 24 hours. Initial uptake was all in lung as expected. Removal of Tc-99m from lung was principally by elution of activity as TcO/sub 4//sup -/ rather than by breakup of the microspheres. Calculated radiation doses in mrad/mCi were as follows: lung, 229; kidney, 138; stomach, 72; thyroid, 72; and bladder wall, 40. Doses to other tissues were all below 40 mrads/mCi.

Wicks, R.; Rosenspire, K.; Ackerhalt, R.; Langan, M.; Steinbach, J.J.; Blau, M.

1981-06-01

321

Zn and Ga play the role of effective magnetic scatterers in high Tc superconductors  

NASA Astrophysics Data System (ADS)

The drastic decrease and ultimate vanishing of Tc in Zn- and Ga-doped YBa 2Cu 3O 7 and La 1.85Sr 0.15CuO 4 is studied theoretically with a model in which Zn and Ga ions play the role of effective magnetic scatterers. The experimental curve for Tc( x) in doped YBa 2Cu 3O 7 can be fitted by the model with both intra-and inter-layer pairing, while Tc( x) in doped La 1.85Sr 0.15CuO 4 is better described by intra-layer pairing only.

Gaji?, R.; Keller, J.; Kuli?, M. L.

1990-11-01

322

Rare decays B?M??¯ in the TC2 model and the LHT model  

NASA Astrophysics Data System (ADS)

In the framework of the topcolor-assisted technicolor ( TC2) model and the littlest Higgs model with T-parity ( LHT model), we consider the rare B decays B?M??¯ with M=?,K,?, or K. We find that the contributions of the TC2 model to the branching ratios of these decay processes are larger than those for the LHT model. The experimental upper limits for some branching ratios can give severe constraints on the free parameters of the TC2 model.

Yue, Chong-Xing; Zhang, Jiao; Liu, Wei

2010-06-01

323

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

324

Influence of intermolecular interactions on the sign of d TC/d p in critical solutions  

NASA Astrophysics Data System (ADS)

Results of studies on variations of the critical temperature ( TC) due to the action of high hydrostatic pressure ( p) are presented. Studies were conducted in three series of critical solutions composed of a dipole component (nitrobenzene, o-nitroluene, 1-nitropropane) and a non-dipole solvent ( n-alkanes). For solutions containing nitrobenzene and o-nitrotoluene the sign and value of d TC/d p depend on the length of the molecule of n-alkane. Additional studies on dipole-dipole interactions between molecules of the dipole components by means of the nonlinear dielectric effect indicate their important influence on d TC/d p.

Urbanowicz, P.; Rzoska, S. J.; Paluch, M.; Sawicki, B.; Szulc, A.; Zio?o, J.

1995-12-01

325

14N nuclear quadrupole resonance of p-nitrotoluene using a high-Tc rf SQUID  

NASA Astrophysics Data System (ADS)

Using a high-Tc radio-frequency superconducting quantum interference device (rf SQUID), we successfully detected nuclear quadrupole resonance (NQR) at about 887 kHz for 14N in p-nitrotoluene (PNT). A normal metal transformer made of copper wire was used to improve the sensitivity of the high-Tc rf SQUID and pulse-controlled rf switches and cross diodes were inserted in the transformer to reduce the influence of the strong excitation field. The preliminary results for NQR detection using the high-Tc SQUID had a similar signal-to-noise ratio to that of using a low noise preamplifier.

He, D. F.; Tachiki, M.; Itozaki, H.

2007-03-01

326

Preparation and evaluation of three mucoadhesive dosage forms using (99m)Tc-Ofloxacin.  

PubMed

Preparation of three mucoadhesive formulations was optimized and pharmaceutically evaluated. Ofloxacin was radiolabeled with (99m)Tc and radiolabeled complex was characterized by HPLC. (99m)Tc-Ofloxacin was added as a tracer to the formulations namely Oflox C934, Oflox C940 and Oflox HPMC and the formulations were fed orally to rats. Imaging studies were carried out to assess the prolonged gastric retention of the formulations. (99m)Tc-Ofloxacin served as a good tracer for studying the pharmacokinetics of three controlled release mucoadhesive dosage forms by gamma scintigraphy studies. PMID:24681624

Mukherjee, Archana; Sahoo, Subhashree; Sarma, Haladhar Dev; Chakraborti, Chandra Kanti; Samuel, Grace

2014-07-01

327

Pharmacokinetic analysis of blood distribution of intravenously administered sup 153 Gd-labeled Gd(DTPA)2- and sup 99m Tc(DTPA) in rats  

SciTech Connect

Rat plasma distribution data obtained following IV administration of {sup 99m}Tc(DTPA) alone or after co-administration of {sup 99m}Tc(DTPA) and {sup 153}Gd-labeled Gd(DTPA)2- at 0.001, 0.1, and 1.0 mmol Gd/kg were evaluated using compartmental modeling techniques. A three-compartment open model was found to fit the data significantly better (P less than 0.01) than a two- or four-compartment open model. This model incorporates and links the plasma and urine data and includes a delay to account for the transit time through the kidneys/ureters. The two nonplasma compartments of the model were assumed to be related to rapidly and slowly equilibrating tissues. Tc(DTPA) and Gd(DTPA)2- had nearly identical pharmacokinetic profiles in plasma and the rate constants were essentially the same. No significant dose dependent pharmacokinetic differences were found for the range of Gd(DTPA)2- doses tested. Simulations of the proposed three-compartment model were used to generate concentration-time curves for each of the three compartments.

Wedeking, P.; Eaton, S.; Covell, D.G.; Nair, S.; Tweedle, M.F.; Eckelman, W.C. (Squibb Institute for Medical Research, New Brunswick, NJ (USA))

1990-01-01

328

Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

Small modular alkali metal thermoelectric generator with no moving parts directly converts heat to electrical energy with efficiency of 20 to 40 percent. Unit uses closed regenerative electrochemical concentration cell based on sodium-ion conductor beta alumina.

Cole, T.

1985-01-01

329

Generation Wrecked.  

ERIC Educational Resources Information Center

Young adults in Generation X are facing financial problems. Because of their college and credit card debt, many in worse financial shape than anyone since the Depression and have little or no retirement savings. (JOW)

Watson, Noshua

2002-01-01

330

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

331

Kinetics of reactions of technetium. VIII. Reduction of Tc(VII) by ascorbic acid in HC1 solution  

Microsoft Academic Search

The reduction of Tc(VII) by ascorbic acid in HCl solution proceeds according to the equation 2TcOâ⁻ + 3CâHâOâ + 10HCl = 2TcClâ⁻ + 3CâHâOâ + 8HâO. The reaction is characterized by an induction period, after the conclusion of which its rate is equal to -d(Tc(VII))\\/dt = k(Tc(VII)) x (CâHâOâ) (H\\/sup +\\/)\\/sup 1.6\\/, where k = 0.898 + 0.064 liter\\/sup 2.6\\/\\/mole\\/sup

V. S. Koltunov; T. V. Gomonova; M. P. Shapovalov; I. G. Abramova

1988-01-01

332

First ex vivo study demonstrating that 99m Tc-NTP 15-5 radiotracer binds to human articular cartilage  

Microsoft Academic Search

Purpose  Preclinical data pointed to 99mTc-NTP 15-5 as a good candidate for single photon emission computed tomography (SPECT) imaging of cartilaginous disease. We\\u000a set out to investigate and quantify 99mTc-NTP 15-5 ex vivo uptake by human articular cartilage relative to bone 99mTc-hydroxymethylene diphosphonate (HMDP) radiotracer.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Three osteoarthritic human tibial plateaux and four tibiofemoral joints were incubated with 99mTc-NTP 15-5 and 99mTc-HMDP for

Florent Cachin; Stéphane Boisgard; Aurélien Vidal; Marc Filaire; Philippe Auzeloux; Damien Culot; Serge Askienazy; Jean-Claude Madelmont; Jean-Michel Chezal; Elisabeth Miot-Noirault

333

Methane generator  

SciTech Connect

A biogas generator is disclosed which includes a medium conducive to the growing of plants that are floating and of the family that includes water hyacinths, lily pads, and elodea; a conveyor for transferring the free floating plants from the growing area to a decomposition area including a canopy adapted to entrain therewithin biogas given off by decomposing plants constrained thereunder, and an instrumentality for scavenging the biogas generated therein to a remote area for subsequent use and or compression.

Whiteside, C.H.

1984-03-27

334

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

335

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

336

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

337

Proximity effect in normal metal high-Tc superconductor contacts  

NASA Astrophysics Data System (ADS)

We study the proximity effect in good contacts between normal metals and high-Tc (dx^2-y^2-wave) superconductors. We present theoretical results for the spatially dependent order parameter and local density of states, including effects of impurity scattering in the two sides, s-wave pairing interaction in the normal metal side (attractive or repulsive) and subdominant s-wave paring in the superconductor side. For the [100] orientation, a real combination d+s of the order parameters is always found. The spectral signatures of the proximity effect in the normal metal include a suppression of the low-energy density of states and a finite-energy peak structure. These features are mainly due to the impurity self-energies, which dominate over the effects of induced pair potentials. For the [110] orientation, for moderate transparencies, induction of a d+is order parameter on the superconductor side leads to a proximity induced is-order parameter also in the normal metal. The spectral signatures of this type of proximity effect are potentially useful for probing time-reversal symmetry breaking at a [110] interface.

Lofwander, Tomas

2005-03-01

338

Proximity effect in normal metal-high- Tc superconductor contacts  

NASA Astrophysics Data System (ADS)

We study the proximity effect in good contacts between normal metals and high- Tc ( dx2-y2- -wave) superconductors. We present theoretical results for the spatially dependent order parameter and local density of states, including effects of impurity scattering in the two sides, s -wave pairing interaction in the normal metal side (attractive or repulsive) and subdominant s -wave paring in the superconductor side. For the [100] orientation, a real combination d+s of the order parameters is always found. The spectral signatures of the proximity effect in the normal metal include a suppression of the low-energy density of states and a finite-energy peak structure. These features are mainly due to the impurity self-energies, which dominate over the effects of induced pair potentials. For the [110] orientation, for moderate transparencies, induction of a d+is order parameter on the superconductor side leads to a proximity induced is order parameter also in the normal metal. The spectral signatures of this type of proximity effect are potentially useful for probing time-reversal symmetry breaking at a [110] interface.

Löfwander, Tomas

2004-09-01

339

High-Tc superconducting microbolometer for terahertz applications  

NASA Astrophysics Data System (ADS)

Superconducting hot electron bolometer mixers are now a competitive alternative to Schottky diode mixers in the terahertz frequency range because of their ultra wideband (from millimeter waves to visible light), high conversion gain, and low intrinsic noise level. High Tc superconductor materials can be used to make hot electron bolometers and present some advantage in term of operating temperature and cooling. In this paper, we present first a model for the study of superconducting hot electron bolometers responsivity in direct detection mode, in order to establish a firm basis for the design of future THz mixers. Secondly, an original process to realize YBaCuO hot electron bolometer mixers will be described. Submicron YBaCuO superconducting structures are expitaxially sputter deposited on MgO substrates and patterned by using electron beam lithography in combination with optical lithography. Metal masks achieved by electron beam lithography are insuring a good bridge definition and protection during ion etching. Finally, detection experiments are being performed with a laser at 850 nm wavelength, in homodyne mode in order to prove the feasibility and potential performances of these devices.

Ulysse, C.; Gaugue, A.; Adam, A.; Kreisler, A. J.; Villégier, J.-C.; Thomassin, J.-L.

2002-05-01

340

High-Tc SQUID Microscopy of Magnetotactic Bacteria  

NASA Astrophysics Data System (ADS)

We present experiments performed on live magnetotactic bacteria (Magnetospirillum magnetotacticum) using a SQUID microscope. Inside a vacuum can, a high-Tc SQUID is mounted on the end of a sapphire rod in thermal contact with a liquid N2 reservoir. A 3?m SiN membrane serves as a vacuum window, 20-30?m above the SQUID. Three layers of mu-metal shield out environmental magnetic fields. Bacteria in growth solution are placed inside a Si well on top of the SiN membrane, where they are detected by the SQUID. Two measurements characterize the bacteria and their dynamics: the magnetic flux noise spectral density due to the motions of the ensemble, and the magnetization of the solution in a uniform magnetic field. Such measurements, carried out on dead bacteria, provide their distributions of sizes and dipole moments. Flux noise data on live bacteria reflect their more complicated dynamics. Features at 25 and 75Hz are vibrations and precessions of the bacteria due to flagellar rotation. Noise at low frequencies is related to the ``run and tumble" motion by which the bacteria swim.

Chemla, Y. R.; Grossman, H. L.; Lee, T. S.; Clarke, John; Adamkiewicz, M.; Buchanan, R.

1998-03-01

341

Terahertz imaging system using high-Tc superconducting oscillation devices  

NASA Astrophysics Data System (ADS)

Microwatt power oscillation devices at sub-terahertz frequency region between 0.3 and 1.0 terahertz (THz) were fabricated from high-Tc superconducting single crystalline Bi2Sr2CaCu2O8+? and used as a source of the transmission terahertz imaging system. As test examples, terahertz images of coins and a razor blade placed inside the brownish paper envelopes with the spatial resolution of 1 mm are presented. The signal-to-noise ratio exceeds 130 in these images. Using a simple wedge-shaped interferometer and analysing the interference fringe pattern, the wavelength of the terahertz wave is calibrated within 0.1% accuracy. This interferometer also provides a simple method to measure the absorption coefficient of the liquid sample. Two test measurements for distilled water and ethanol are demonstrated and their absorption coefficients are obtained with 99.2% accuracy. This suggests that our terahertz imaging system can be applied to many practical applications, such as biological and biomedical imaging, environmental monitoring, microanalysis of impurities, structure and dynamical analyses of large molecules and ions in solution.

Tsujimoto, M.; Minami, H.; Delfanazari, K.; Sawamura, M.; Nakayama, R.; Kitamura, T.; Yamamoto, T.; Kashiwagi, T.; Hattori, T.; Kadowaki, K.

2012-06-01

342

Observing the fluctuating stripes in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

Superfluids and superconductors have been around for a long time and their explanation in terms of the Bogoliubov theory for bosons and the BCS theory for fermions belong to the highlights of twentieth century physics. However, it appears that these theories are too primitive to address the high-Tc superconductivity found in copper oxides. These electron systems seem to behave more like a dense, strongly correlated liquid contrasting markedly with the conventional quantum gasses: these show strong dynamical correlations on mesoscopic length and time scales associated with stripes, a particular form of electron crystallization. Resting on the gauge theory of topological quantum melting in 2+1 dimensions relevant for the cuprates, we describe the limit which is exactly opposite to the gas limit: the superconductor with the maximum possible amount of transient translational order. We predict that in this "orderly limit" an extra collective mode appears, and this "massive shear photon" can be regarded as a universal fingerprint of the fluctuating stripes. This mode is visible in the electrodynamic response and the ramification of our theory is that electron energy loss spectroscopy can be employed to prove or disprove the existence of dynamical stripes in cuprate superconductors.

Cvetkovic, V.; Nussinov, Z.; Mukhin, S.; Zaanen, J.

2008-01-01

343

Quadrupole couplings and magnetic shielding anisotropy of technetium-99 in TcO{sub 4}{sup -} anion  

SciTech Connect

Free pertechnetate anion TcO{sub 4}{sup -} in solutions exhibits the tetrahedral T{sub d} symmetry. In solid state, TcO{sub 4}{sup -} experiences slight structural distortions. A splitting of the antisymmetric {nu}{sub 3} vibrational frequency usually serves as a qualitative criterion of the TcO{sub 4}{sup -} distortion. However, the distortion derived from the {nu}{sub 3} splittings is inconsistent with that determined by X-ray crystallography. Earlier, the authors have shown for a series of scheelite-like pertechnetates that the TcO{sub 4}{sup -} distortions are quantitatively characterized by the {sup 99}Tc quadrupole coupling constant (QCC). According to the QCC values, the greatest distortion should be expected for sodium and silver pertechnetates. The structural distortion of TcO{sub 4}{sup -} is caused by asymmetric electron distribution in the anion, which would manifest itself in anisotropy of {sup 99}Tc magnetic shielding.

Tarasov, V.P.; Privalov, V.I. [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation)

1995-11-01

344

Mitochondrial localization and characterization of 99Tc-SESTAMIBI in heart cells by electron probe X-ray microanalysis and 99Tc-NMR spectroscopy.  

PubMed

As the development of targeted intracellular magnetic resonance contrast agents proceeds, techniques for the quantitative analysis of the subcellular compartmentation and characterization of metallopharmaceuticals must also advance. To this end, the subcellular distribution and chemical state of hexakis (2-methoxyisobutyl isonitrile) technetium-99 (99Tc-SESTAMIBI), the ground state of the organotechnetium radiopharmaceutical used for the noninvasive evaluation of myocardial perfusion and viability by scintigraphy, has been determined by a novel application of electron probe X-ray microanalysis (EPXMA) and 99Tc-NMR spectroscopy. In cryopreserved cultured chick heart cells equilibrated in 36 microM 99Tc-SESTAMIBI, EPXMA imaging of mitochondria yielded a respiratory uncoupler-sensitive characteristic 99Tc X-ray peak representing 32.0 +/- 2.9 nmoles Tc/mg dry weight, while EPXMA of cytoplasm or nucleus showed no peak significantly greater than the threshold detectability limit of approximately 1 nmole/mg dry weight. Technetium-99 NMR spectroscopy of heart cells equilibrated with 99Tc-SESTAMIBI showed a single peak at -45.5 ppm with no evidence of significant line broadening or chemical shift compared to aqueous chemical standards, indicating that the majority of the complex exists unbound within the mitochondrial matrix. These data quantitatively demonstrate the localization of this lipophilic cationic organometallic complex within mitochondria in situ, consistent with a sequestration mechanism dependent on membrane potentials. Furthermore, this study establishes the general feasibility of combined EPXMA and NMR spectroscopy for the direct subcellular localization and characterization of metallopharmaceuticals, techniques that are readily applicable to MR contrast agents. PMID:8057769

Piwnica-Worms, D P; Kronauge, J F; LeFurgey, A; Backus, M; Hockett, D; Ingram, P; Lieberman, M; Holman, B L; Jones, A G; Davison, A

1994-01-01

345

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  

SciTech Connect

The combination of pyridine ligands, (OCl{sub 4}Tc){sup {minus}}, and O atom acceptors of different cone angles, such as PMe{sub 2}Ph or PPh{sub 3}, results in Tc{sup III} complexes that vary in the coordination of the phosphine ligand. The compounds mer(Cl{sub 3}(4-picoline){sub 3}Tc) and mer-(Cl{sub 3}(4-picoline)(PMe{sub 2}Ph){sub 2}Tc) have been obtained in good yield and have been characterized spectroscopically and by single-crystal x-ray diffraction. The crystal structure data are reported. Linear correlations of technetium reduction potentials in DMF with electrochemical ligand additivity parameters (E{sub L}'s) have been obtained for the Tc{sup II,I}, Tc{sup III,II}, and Tc{sup IV,III} couples. The slope and intercept (S{sub M}, I{sub M}) pairs for each technetium oxidation-reduction couple, respectively, are (1.39, {minus}2.07), (1.29, {minus}0.91), and (1.00, 0.65). 32 refs., 3 figs., 6 tabs.

Lu, Jun; Yamano, Akahito; Clarke, M.J. (Boston College, Chestnut Hill, MA (USA))

1990-09-05

346

Generation of high-order optical vortices with asymmetrical pinhole plates under plane wave illumination.  

PubMed

We propose a novel and simple method for generating optical vortex with high topological charge (TC), merely using an asymmetrical pinhole plate illuminated by plane wave. N pinholes are arranged along a particular spiral line around the plate origin, with constant azimuth angle increment and varied radial distances. The radial differences introduce a constant variation of m/N wavelength to the optical paths from the N pinholes to the observation plane origin, and this increases the phases of the transmitting waves by progressively 2m?/Nand totally 2m?. We numerically calculate the transmitted light field according to the Fresnel diffraction theory, and find the vortex with TC m around the observation plane origin. The experimental verifications are performed using some self-made asymmetrical pinhole plates fabricated by a femtosecond laser, with the high TC vortices both generated and detected in a Mach-Zehnder type interferometer. The experimental results coincide with the theoretical simulations well. PMID:23842362

Li, Zhenhua; Zhang, Meina; Liang, Guotao; Li, Xing; Chen, Xiaoyi; Cheng, Chuanfu

2013-07-01

347

Mono- and dicationic Re(I)/(99m)Tc(I) tricarbonyl complexes for the targeting of energized mitochondria.  

PubMed

The enhanced negative mitochondrial membrane potential of tumor cells can increase the cell accumulation of triphenylphosphonium (TPP) derivatives, which prompted us to investigate TPP-containing Re(I)/(99m)Tc organometallic compounds as probes for in vivo targeting of energized mitochondria. Novel compounds (Re1-Re4/Tc1-Tc4) were obtained with bifunctional chelators of the pyrazole-diamine (N,N,N-donors) and pyrazole-aminocarboxylic (N,N,O-donors) type, functionalized with TPP pharmacophores that have been introduced at the central amine of the chelators using different spacers. In this way, dicationic (Re1-Re2, Tc1-Tc2) and monocationic (Re3-Re4, Tc3-Tc4) complexes with variable lipophilicity were synthesized. The (99m)Tc complexes (Tc1-Tc4) are highly stable under physiological conditions and their chemical identification was done by HPLC comparison with the Re congeners (Re1-Re4), which were fully characterized by common analytical techniques (electrospray ionization mass spectrometry (ESI-MS), IR, multinuclear NMR). The in vitro biological evaluation of Tc1-Tc4 was performed in a panel of human tumor cell lines (PC-3, MCF-7 and H69), including cell lines overexpressing P-glycoprotein (MCF-7/MDR1 and H69/Lx4), and in isolated mitochondria. All the tested complexes showed a low to moderate cellular and mitochondrial uptake and did not undergo significant P-glycoprotein (Pgp)-mediated efflux processes. In particular, the dication Tc2 and the monocation Tc4 presented the highest cellular and mitochondrial uptake. Their cellular uptake was shown to depend on the mitochondrial (??m) and plasma membrane (??p) potentials. Altogether, the biological properties of these compounds suggest that they might be relevant for the design of radioactive metalloprobes for in vivo targeting of mitochondria. PMID:23507077

Moura, Carolina; Mendes, Filipa; Gano, Lurdes; Santos, Isabel; Paulo, António

2013-06-01

348

Labeling of phagocytes from human blood with 99mTc-sulfur colloid.  

PubMed

Experments in this report have shown that peripheral blood leukocytes can be readily labeled with 99mTc-sulfur colloid during in vitro incubation. Phagocytic cells were preferentially labeled by this method. Labeling was enhanced in the presence of normal serum. The data suggest that labeling was accomplished by phagocytosis of the radiocolloid. Labeled granulocytes responded normally to chemotactic stimuli and excluded trypan blue dye normally. Buffy coat cells from 50 ml of peripheral blood could be labeled with 8 mCi of 99mTc after incubation with 20 mCi of TcSC. This report offers a method by which phagocytic cells can be selectively labeled with 99mTc in amounts suitable for scintillation scanning. PMID:1110404

English, D; Andersen, B R

1975-01-01

349

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

350

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

351

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

352

Antibody Studies in Ponies Vaccinated with Venezuelan Equine Encephalomyelitis (Strain TC-83) and other Alphavirus Vaccines.  

National Technical Information Service (NTIS)

Serologic studies in 24 ponies indicated that prevaccination antibodies to Venezuelan equine encephalomyelities (VEE) virus (strain TC-83) had no influence on hemagglutination-inhibition (hi) antibody stimulation by Western equine encephalomyelitis (EEE) ...

J. A. Ferguson W. C. Reeves J. L. Hardy

1976-01-01

353

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

354

High Temperature Magnetic Ordering in the 4d Perovskite SrTcO3  

NASA Astrophysics Data System (ADS)

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.

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.

2011-02-01

355

Changes of the reactor performance and the properties of granular sludge under tetracycline (TC) stress.  

PubMed

In this study, the response of nitrifying granules (NG) and conventional granules (CG) to tetracycline (TC) was compared. The presence of TC made granules break down into small fractions and led to nitrite accumulation in nitrifying system; while it had little toxic effect on CG system. Specific oxygen uptake rate tests showed 3.3% inhibition of ammonium oxidizing bacteria and 25.7% inhibition of nitrite oxidizing bacteria in the NG system. Granules produced more extracellular polymeric substances (EPS) to protect themselves from the TC stress, with higher production of proteins compared to polysaccharides. FTIR data also revealed significant changes of protein functional groups, while only small changes in polysaccharides functional groups were found. Three dimensional excitation-emission matrix fluorescence spectroscopy showed a decrease of peak intensity, indicating quenching effect of TC on EPS fluorescence, and also a blue shift of peak position, indicating chemical changes of EPS components. PMID:23660380

Shi, Yijing; Xing, Sufang; Wang, Xinhua; Wang, Shuguang

2013-07-01

356

[Diagnostic possibilities of static gamma-scintigraphy using 99mTc pyrophosphate and Tc 99m phosphate in children with glomerulo nephritis].  

PubMed

Children with nephrotic glomerulonephritis were examined for incorporation of 99mTc-pyrophosphate and 99mTc-phosphone. The relationship was discovered between the accumulation of the radiopharmaceutical drug and the sensitivity to glucocorticoids used in the pathogenetic treatment. Accumulation of the drug in the course of the treatment documents the presence of complete, partial remission or the disease activity. It is recommended that static gammascintigraphy should be carried out for early assessment of the efficacy of the treatment and its correction. PMID:2549499

Mil'ko, V I; Bagdasarova, I V; Moskalenko, N I; Ivanov, D D

1989-01-01

357

Myocardial kinetics of 201 Thallium, 99m Tc-tetrofosmin, and 99m Tc-sestamibi in an acute ischemia–reperfusion model using isolated rat heart  

Microsoft Academic Search

Objective  \\u000a 201Thallium (TL), 99mTc-tetrofosmin (TF), and 99mTc-sestamibi (MIBI) are extensively used as myocardial perfusion agents. The objective of the present study was to evaluate\\u000a their kinetics under acute ischemia–reperfusion.\\u000a \\u000a \\u000a \\u000a Methods  Isolated rat hearts, perfused by the Langendorff method at a constant flow rate of 10?ml\\/min, were allotted to normal control,\\u000a mild ischemia, and severe ischemia groups, in which 20-min tracer wash-in

Kenji Fukushima; Mitsuru Momose; Chisato Kondo; Kiyoko Kusakabe; Hiroshi Kasanuki

2007-01-01

358

Evaluation of (99m)Tc(i)-tricarbonyl complexes of fluoroquinolones for targeting bacterial infection.  

PubMed

The aim of this study was to develop (99m)Tc(CO)(3)-labeled fluoroquinolones as novel SPECT radiopharmaceuticals for imaging bacterial infection. Fluoroquinolones, e.g., ofloxacin (OFX), levofloxacin (LVX), lomefloxacin (LMX) and norfloxacin (NFX) were labeled with a fac-[(99m)Tc(CO)(3)(H(2)O)(3)](+) precursor. The radiochemical purity of the radiopharmaceuticals exceeded 97% as determined by thin layer chromatography and HPLC. No further purification was necessary before injection. The Re(CO)(3) complex of one of the fluoroquinolones (levofloxacin) was synthesized using [Re(CO)(3)(H(2)O)(3)]OTf and Re(CO)(5)Br precursors in separate experiments and characterized by IR, NMR and mass spectroscopic analysis. These studies revealed the formation of a single species in which the piperazinyl nitrogen and the -COOH group attached to the benzoxazine ring system of quinolone were involved in co-ordination to the Re(CO)(3) core. The HPLC elution pattern and retention time of the Re(CO)(3)-LVX complex were comparable to those of the corresponding (99m)Tc(CO)(3)-complex proving their similarity. When incubated in isotonic saline and serum up to 24 h (99m)Tc(CO)(3)-labeled fluoroquinolones exhibited good in vitro stability. Biodistribution studies performed at different time points on rats intramuscularly infected with S. aureus as well as on rats with sterile inflammation revealed a higher uptake in the infected area than the turpentine induced inflamed area. The uptake in infected thigh was significant with (99m)Tc(CO)(3)-OFX followed by (99m)Tc(CO)(3)-LVX. The mean ratios of the uptake in infected/non-infected thighs were 4.75 and 4.27 at 8 h and 24 h, respectively, for (99m)Tc(CO)(3)-OFX and 4.42 and 4.18 at 24 h and 8 h, respectively, for (99m)Tc(CO)(3)-LVX. The above abscess to muscle ratios were higher than reported for (99m)Tc-ciprofloxacin and other (99m)Tc-labeled fluoroquinolones. Scintigraphy studies also showed a significant uptake in the infectious lesions suggesting that (99m)Tc(CO)(3)-fluoroquinolones might be useful as diagnostic agents for targeted delivery in bacterial infection. PMID:23073602

Nayak, Dipak Kumar; Baishya, Rinku; Halder, Kamal Krishna; Sen, Tuhinadri; Sarkar, Bharat R; Ganguly, Shantanu; Das, M K; Debnath, Mita Chatterjee

2012-11-01

359

Radiochemical sensor system for the analysis of 99 Tc(VII) in groundwater  

Microsoft Academic Search

Summary  Direct determination of 99Tc in groundwater using a sensor device represents a substantial challenge due to the short range of beta-particles, the presence of radiological interferences, and low-level detection requirements. This paper describes a radiochemical sensing method for selective detection of 99Tc(VII) in water. The sensing approach uses a dual-function composite sensor microcolumn that incorporates both selective sorption and scintillating

J. Hartman; Matthew J. OHara; Jay W. Grate; Michael A. Knopf; G Anderson

2005-01-01

360

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

361

Forensic validation of the STR systems SE 33 and TC 11  

Microsoft Academic Search

Summary Population studies on Caucasians from northwest Germany were carried out using the short tandem repeat (STR) systems SE 33 (Locus: ACTBP2) and TC 11 (Locus: 11p15.5). After electrophoresis in PAG 26 alleles could be identified for SE 33 in a sample size of 180 unrelated individuals and 6 alleles were found for TC 11 in 110 individuals. The combined

P. Wiegand; B. Budowle; S. Rand; B. Brinkmann

1993-01-01

362

Evaluation of polyethylene glycol coated liposomes labeled with Tc-99m as a blood pool agent  

SciTech Connect

This investigation evaluated Tc-99m liposomes coated with polyethylene glycol (PEG) as a blood pool agent in comparison with Tc-99m liposomes carrying no surface charge (Neutral) and with Tc-99m autologous red cells. Liposomes (135 nm diameter) encapsulating glutathione were labeled with Tc-99m using the lipophilic chelator, HMPAO as previously described. Autologous red cells were labeled using an Ultratag kit. Labeling efficiencies averaged 66%, 52%, and 97% for the PEG liposomes. Neutral liposomes, and red cells, respectively. Rabbits (3-3.5 Kg) were injected IV via ear vein with 2.0 mls of PEG liposomes (2 mCi, 17 mg phospholipid/Kg body weight, n=5). Neutral liposomes (1.3 mCi, 17 mg phospholipid/Kg body weight, n=4), or red cells (2.6 mCi, n=2). Gamma camera images were acquired at 5,22, and 45 minutes, and 2,20,and 44 hours post-injection. Blood samples were obtained at each time point to determine clearance kinetics. Circulation half lives of both Tc-99m liposome formulations were longer than Tc-99m red cells (8 hrs), with the half life of PEG liposomes (35 hrs) 1.6 times longer than Neutral liposomes (22 hrs). In vivo stability of the Tc-99m label was excellent for the liposomes with only 3.5-4% bladder activity at 45 minutes compared to 12% bladder activity for the red cells. Excellent blood pool images were obtained for the PEG liposomes in the rabbit. Heart/liver ratios calculated from region of interest analysis of 45 minutes images were 1.9, 1.5, and 1.7 for PEG liposomes, Neutral liposomes and red cells. This study demonstrates the feasibility of using Tc-99m PEG liposomes to perform gated cardiac blood pool and rapid gastrointestinal bleeding studies.

Phillips, W.T.; Klipper, R.; Goins, B. [Univ. of Texas Health Science Center, San Antonio, TX (United States)

1994-05-01

363

DC and AC Shielding Properties of Bulk High-Tc Superconducting Tubes  

Microsoft Academic Search

We have studied numerically and experimentally the magnetic flux penetration in high-Tc superconducting tube subjected to a uniform magnetic field parallel to its long axis. This study is carried in view of designing low-frequency magnetic shields by exploiting the diamagnetic properties of high-Tc superconducting ceramics. We have measured the field attenuation for applied magnetic fields in the frequency range 5

Jean-Francois Fagnard; Samuel Denis; Gregory Lousberg; Michel Dirickx; Marcel Ausloos; Benoit Vanderheyden; Philippe Vanderbemden

2009-01-01

364

Characterization of a transcriptionally active Tc1-like transposon in the microsporidian Nosema bombycis  

Microsoft Academic Search

The Tc1 transposable element has been found in a wide variety of organisms including vertebrates, insects and fungi but has\\u000a not been previously reported in Microsporidia. In this study we characterize an intact DNA transposon (NbTc1) from the microsporidian Nosema bombycis. This transposable element encodes a 337 amino acid transposase sequence, which contains the D,D34E functional motif required\\u000a for transposition.

Jinshan Xu; Jie Luo; Bettina Debrunner-Vossbrinck; Xiaoyan Zhang; Hangdeng Liu; Zeyang Zhou

2010-01-01

365

Thyroid examination with radionuclides ¹³¹I and \\/sup 99m\\/Tc  

Microsoft Academic Search

The thyroid examination with simultaneous administration of ¹³¹I ; and \\/sup 99m\\/Tc is reported. For iodine uptake and iodine metabolism an amount ; of 4 to 10 mu Ci ¹³¹I is applied, for scintigraphy 0.5 to 1.0 mCd \\/sup ; 99mTc-pertechnetate. Six hundred and four examinations were made according to ; this method and compared with the same number of

Rohacek

1973-01-01

366

The Thlaspi caerulescens NRAMP Homologue TcNRAMP3 is Capable of Divalent Cation Transport  

Microsoft Academic Search

The NRAMP gene family encodes integral membrane protein and mediates the transport of Fe, however, its function in transport\\u000a of toxic metal ions is not very clear in plants. TcNRAMP3 was isolated from Thlaspi caerulescens, and encoded a metal transporter member of the NRAMP family. TcNRAMP3 was predominantly expressed in roots of T. caerulescens by semi-quantitative RT-PCR. The expression of

Wei Wei; Tuanyao Chai; Yuxiu Zhang; Lu Han; Jin Xu; Ziqiu Guan

2009-01-01

367

Synthesis and identification of the monocation Tc(CPI) sub 6 sup + in Tc(CNC(CH sub 3 ) sub 2 COOCH sub 3 ) sub 6 Cl and its hydrolysis products. [Tc(CNC(CH sub 3 ) sub 2 COOCH sub 3 ) sub 6 Cl and monocation Tc(CPI) sub 6 sup +  

Microsoft Academic Search

The complex Tc(CNC(CHâ)âCOOCHâ)âCl (cation designated as Tc(CPI)â{sup +}) is one of a series of isonitrile-coordinated technetium complexes being investigated as a prototype radiopharmaceutical to evaluate myocardial perfusion. It has been prepared from the pertechnetate ion by aqueous NaâSâOâ reduction in the presence of the functionalized isocyanide ligand. The octahedral compound with its relatively reactive ester substituents is stable under aqueous

J. F. Kronauge; A. Davison; A. M. Roseberry; C. E. Costello; S. Maleknia; A. G. Jones

1991-01-01

368

An alkaline kit formulation to obtain [ 99m Tc]MAG 3 in high radiochemical yields  

Microsoft Academic Search

An alkaline kit formulation (pH 9) to obtain [99mTc]MAG3 with radiochemical puritives over 98% has been developed, avoiding the addition of filtered air to the vial, the use of large amounts of99mTc activity (i.e., 3.7 GBq) or the reconstitution of large volumes. The use of this radiopharmaceutical in mice showed a minimal accumulation in the hepatobiliary system (0.37±0.3% I.D., 1

L. Reyes-Herrera; G. Ferro-Flores; J. Lezama-Carrasco; M. A. Gonzalez-Zavala; F. Ureña-Nuñez; E. Avila-Ramirez

1995-01-01

369

Scintigraphic detection of osteomyelitis with Tc99m MDP and Ga67 citrate: concise communication. [Rabbits  

Microsoft Academic Search

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.

G. D. Graham; M. M. Lundy; R. J. Frederick; M. F. Hartshorne; D. E. Berger

1983-01-01

370

99m Tc-sestamibi kinetics predict myocardial viability in a perfused rat heart model  

Microsoft Academic Search

Introduction  \\u000a 99mTc-sestamibi has been proposed as a viability imaging agent. The purposes of this study were: (1) to determine the relationship\\u000a between myocardial viability and 99mTc-sestamibi kinetics using perfused rat heart models across a full spectrum of viability, (2) to do so under conditions where\\u000a myocardial flow was controlled and held constant, and (3) to do so using multiple quantitative

Zhonglin Liu; David R. Okada; Gerald Johnson; Sonia D. Hocherman; Delia Beju; Robert D. Okada

2008-01-01

371

A Precision Low-TC Wide-Range CMOS Current Reference  

Microsoft Academic Search

This paper describes a programmable temperature-compensated CMOS current reference. The proposed circuit achieves a first-order temperature compensation by canceling the negative temperature coefficient (TC) of an on-chip poly resistor with the positive TC of a MOS transistor operating in the ohmic region. Programmability of the current reference is enabled with the use of floating-gate transistors, thus allowing arbitrary current values

Guillermo Serrano; Paul Hasler

2008-01-01

372

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. Sánchez; M. Elwenspoek; T. Heidenblut; B. Schwierzi; W. Michalke; E. Steinbeiss

1997-01-01

373

Technetium-99 ((99)Tc) in annual growth segments of knotted wrack (Ascophyllum nodosum).  

PubMed

The distribution of technetium-99 ((99)Tc) in annual growth segments of the brown seaweed Ascophyllum nodosum (Fucales, Phaeophyceae) from the southwestern coast of Norway is examined in samples collected from January to November 2006. A twenty-fold increase in the (99)Tc-concentration from the youngest to the oldest growth segments was found. The concentrations ranged from 42 to 98Bq/kg dry weight (d.w.) and from 964 to 1000Bq/kg d.w. in growth segments formed in 2006 and 1996, respectively. In addition, a seasonal variation in the (99)Tc concentration was observed in the actively growing 2006-segments: concentrations decreased from 98Bq/kg d.w. in April to 54Bq/kg d.w. in June; there was a further reduction from June to August (42Bq/kg d.w.); and, finally there was an increase from August to November (93Bq/kg d.w.). In most of the segments formed between 2000 and 2005, there was a tendency of slightly decreasing (99)Tc-concentrations between June and November but this pattern was not observed for the older growth segments. In order to find an explanation for the non-homogenous distribution of (99)Tc within thalli of A. nodosum, different hypotheses are discussed. Uptake and elimination of (99)Tc appears to be most pronounced in the actively growing segments. To date, such non-homogenous distribution of (99)Tc within thalli of A. nodosum has not been taken into consideration, neither in connection with sample collection nor analysis. This paper shows that special protocols must be followed if A. nodosum is going to be used as a bioindicator for (99)Tc in the marine environment. A sampling strategy is proposed. PMID:20801489

Heldal, Hilde Elise; Sjøtun, Kjersti

2010-10-15

374

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

375

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

376

Physics of Elementary Particles and Fields One-Loop Effects of Non-Universal Gauge Boson Z' in Top Quark Pair Production at LHC in TC2 Model  

NASA Astrophysics Data System (ADS)

The top color-assisted technicolor model (TC2) predicts a non-universal Z' gauge boson, which couples to the third generation fermions with enhanced strength. We study the effects of this non-universal gauge boson on the cross section and spin correlation of top quark pair production through the process gg ? tt¯ at the LHC. We find that the total cross section and the spin correlation can be reduced by -4.7% and -1.4% respectively in the allowed parameter space.

Liu, Ning; Wu, Lei

2011-02-01

377

Solvent extraction of 99Tc from radioactive intermediate liquid waste by dibenzo-18-crown-6.  

SciTech Connect

Technetium is one of the most prominent problems since its most stable specie in the environment, the pertechnetate ion, is highly mobile and considered as a long-term hazard in nuclear waste disposal. Because of the small activities of 99Tc relative to other fission products 137Cs or 90Sr, and its long half-life time (t1/2 = 2.1x10{sup 5} yrs), 99Tc is one of the key isotopes that should always be analyzed in the radioactive liquid waste streams from the reprocessing industry where the largest concentrations are to be expected. Furthermore, as a pure betaemitter, 99Tc has to be isolated from the intermediate level waste (ILW) stream prior to any measurement in such complex media. We have developed a method for 99Tc extraction providing recommendations that will be useful for extracting it from acid and basic ILW. The extraction of 99Tc from ILW by dibenzo-18-crown-6 (DB18C6) has been investigated and a simplex optimization of key parameters involved in the procedure has allowed us to set up their best values. Experiments have been carried out on synthetic and real effluents from La Hague reprocessing plant, France, and results show that DB18C6 is highly selective towards 99Tc. The application of this procedure has been successfully demonstrated through the analysis of actual waste streams coming from two reprocessing plants at La Hague and Marcoule, France.

Paviet-Hartmann, P. (Patricia)

2001-01-01

378

Influence of structural parameters on Tc in superconducting R Ni2 B2 C compounds  

NASA Astrophysics Data System (ADS)

The superconducting transtition temperature Tc in nonmagnetic Lu1-xLaxNi2B2C (x?0.1) linearly decreases with the structural parameter c'/a as dTc/d(c'/a)=210(20)K . The same decrease of dTc/d(c'/a) has been observed for the other nonmagnetic series Lu1-xYxNi2B2C (x?0.1) [J. Freudenberger, S. L. Drechsler, G. Fuchs, A. Kreyssig, K. Nenkov, S. V. Shulga, K.-H. Müller, and L. Schultz, Physica C 306, 1 (1998); J. Freudenbenger, Paarbrechung in Seltenerd-Übergangsmetall-Borkarbiden, Thesis, TU, Dresden, 2000]. The decrease in Tc for the antiferromagnetically (AF) ordered compounds RNi2B2C ( R=Dy ,Ho,Er,Tm) and for nonmagnetic LuNiBC again scales as [dTc/d(c'/a)]=200(10)K . This is a strong indication that in nonmagnetic and AF ordered RNi2B2C as well as RNiBC compounds Tc is determined by c'/a which is a measure for the deviation of the NiB4 tetrahedra from ideal tetrahedral symmetry.

Sánchez, D. R.; Micklitz, H.; Baggio-Saitovitch, E. M.

2005-01-01

379

Field-Scale Migration of 99Tc and 129I at the Nevada Test Site  

SciTech Connect

The groundwater at the Nevada Test Site (NTS) contains many long-lived radionuclides, including {sup 99}Tc (technetium) and {sup 129}I (iodine), as a result of 828 underground nuclear weapons tests conducted between 1951 and 1992. We synthesized a body of data collected on the distribution of {sup 99}Tc and {sup 129}I in groundwater to assess their migration at NTS, at field scales over distances of hundreds of meters and for durations up to forty years and under hydrogeologic conditions very similar to the proposed geological repository at Yucca Mountain. The results of our study show that Tc does not necessarily exist as a mobile and conservative species TcO{sub 4}{sup -}, as has been commonly assumed. This conclusion is corroborated by recent in situ redox potential measurements, which show that groundwaters at multiple locations of the NTS are not oxidizing, and mobility of reduced Tc species (TcO{sub 2} {center_dot} nH{sub 2}O) is greatly decreased. Speciation of iodine and its associated reactivity is also complex in the groundwater at the NTS, and its effect on the mobility of iodine should be the subject of future studies.

Hu, Q; Smith, D K

2004-03-29

380

Calculation of the pairing temperature Tc and the gap function in electron-doped cuprates  

NASA Astrophysics Data System (ADS)

Using a spin-Fermion model, and applying an Eliashberg-type theory to electron-doped cuprates at quantum criticality, we calculate the pairing transition temperature Tc, and the gap function ?(k, ?n) for T<Tc. We carry out the calculation with a frequency dependent interaction, mediated by spin fluctuations exchange. We argue that for near-critical electron-doped cuprates, the geometry of the problem is such that the Fermi surface curvature plays an important role in the calculation of the polarization bubble ?, the fermionic self energy ?, as well as the anomalous self energy ?02. For T<Tc the polarization ? also depends on ?(k, ?n). As an advantage over previous works, vertex corrections are also included in our calculations. We show that vertex corrections actually give rise to a larger Tc and explain why. For T<Tc, we obtain a gap function ?(k, ?n) that is non-monotonic along the Fermi-surface, but monotonically decreases as a function of frequency ?n. We find that the ratio of the maximum of ? to Tc is around 1.8 without vertex corrections; with the corrections it is around 4.

Dhokarh, Dhananjay; Chubukov, Andrey

2010-03-01

381

/sup 99m/Tc(Sn)-N-pyridoxylaminates: a new series of hepatobiliary imaging agents  

SciTech Connect

Three derivatives of N-pyridoxylamino acid were synthesized: /sup 99m/Tc(Sn)-N-pyridoxylphenylalanine, -N-pyridoxyltryptophan, and -N-pyridoxyl-5-methyltryptophan. The chemical and biologic properties of each complex was found to be quite analogous to those of the corresponding /sup 99m/Tc(Sn)pyridoxylideneaminate. In rats, /sup 99m/Tc(Sn)-N-pyridoxyl-5-methyltryptophan (/sup 99m/Tc(Sn)PHMT) showed rapid blood clearance, fast hepatobiliary transit, low urinary excretion, and no intestinal reabsorption. Over 90% of the dose arrived in the intestine through the liver at 30 min after i.v. administration, whereas only 2% of the dose escaped through the kidneys. In rabbits the gallbladder was clearly visualized within 5 min of injection and no renal or bladder images were noted on any scintiphotos. The BSP (sulfobromophthalein) intervention study revealed that the biliary excretion of /sup 99m/Tc(Sn)PHMT is much more resistant than that of /sup 99m/Tc(Sn) diethyl-IDA to the intervention of BSP and hence to serum bilirubin. Toxicity studies on PHMT and Sn-PHMT indicated a wide margin of safety for the proposed human dose.

Kato-Azuma, M.

1982-06-01

382

Initial experience with Tc-99m-HM-PAO in the study of brain tumors.  

PubMed

A preliminary study of the distribution of the 99mTc complex of hexamethylpropylene amine oxime (HM-PAO) in 12 patients with brain neoplasms before, during, and after radiotherapy has been performed. Untreated brain tumors were found to exhibit a range of 99mTc-HM-PAO uptake, varying from areas of markedly increased isotope activity to photopenic areas, when compared to normal brain tissue. A ratio of 99mTc-HM-PAO tumor uptake to contralateral normal tissue uptake was calculated prior to and during radiotherapy. This ratio tended to return towards unity in lesions responding to therapy. A predictable alteration in whole brain 99mTc-HM-PAO uptake during radiotherapy was not demonstrated. Unlike the radiolabeled amines, 99mTc-HM-PAO localizes in primary tumors, probably indicating that its uptake mechanism is independent of non specific amine receptors. 99mTc-HM-PAO may be useful in the study of brain tumor physiology and response to therapy. PMID:2838284

Babich, J W; Keeling, F; Flower, M A; Repetto, L; Whitton, A; Fielding, S; Fullbrook, A; Ott, R J; McCready, V R

1988-01-01

383

Parathyroid adenoma detected with 99mTc-tetrofosmin dual-phase scintigraphy: a case report  

PubMed Central

Background Tc-sestamibi is the most frequently used radionuclide agent for the detection of parathyroid adenomas in the clinical setting. However, Tc-tetrofosmin is another such agent that may be used for this purpose. This case report presents the significance and practicality of 99mTc-tetrofosmin for the diagnosis of parathyroid adenomas with probable high p-glycoprotein levels. Case presentation A 45-year-old woman was referred to our Nuclear Department with a palpable neck nodule suspicious for parathyroid adenoma. She had no significant medical history or other accompanying symptoms. Blood examination results were normal with the exception of the parathormone level which was high at 167.2 pg/ml. Neck ultrasonography revealed a hypoechoic mass near the lower pole of the thyroid gland. 99m Tc-tetrofosmin dual-phase scintigraphy with early and delayed images was performed and the results supported the presupposition of parathyroid adenoma as shown by increased radiopharmaceutical levels near the lower left thyroid gland on the early image that disappeared on the delayed image. Moreover, TcO4? thyroid scintigraphy results excluded thyroid pathology. Two months after the diagnosis, parathyroidectomy was successfully performed without postoperative complications. The pathology report and clinical response to a gradual decrease of parathormone confirmed the initial diagnosis. Conclusion We strongly recommend the use of reverse 99m Tc-tetrofosmin scintigraphy as a useful and safe examination technique for the diagnosis of parathyroid adenomas.

2014-01-01

384

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

385

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

386

SOLVENT EXTRACTION OF 99Tc FROM RADIOACTIVE INTERMEDIATE LIQUID WASTE BY DIBENZO-18-CROWN-6  

SciTech Connect

Technetium is one of the most prominent problems since its most stable specie in the environment, the pertechnetate ion, is highly mobile and considered as a long-term hazard in nuclear waste disposal. Because of the small activities of 99Tc relative to other fission products 137Cs or 90Sr, and its long half-life time (t1/2 = 2.1 x 105 yrs), 99Tc is one of the key isotopes that should always be analyzed in the radioactive liquid waste streams from the reprocessing industry where the largest concentrations are to be expected. Furthermore, as a pure beta-emitter, 99Tc has to be isolated from the intermediate level waste (ILW) stream prior to any measurement in such complex media. We have developed a method for 99Tc extraction providing recommendations that will be useful for extracting it from acid and basic ILW. The extraction of 99Tc from ILW by dibenzo-18-crown-6 (DB18C6) has been investigated and a simplex optimization of key parameters involved in the procedure has allowed us to set u p their best values. Experiments have been carried out on synthetic and real effluents from La Hague reprocessing plant, France, and results show that DB18C6 is highly selective towards 99Tc. The application of this procedure has been successfully demonstrated through the analysis of actual waste streams coming from two reprocessing plants at La Hague and Marcoule, France.

Paviet-Hartmann, P.

2002-02-25

387

Fermi surface reconstruction in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

The recent observation of quantum oscillations in underdoped high-Tc superconductors (1), combined with their negative Hall coefficient at low temperature (2), reveals that the Fermi surface of hole-doped cuprates includes a small electron pocket. This strongly suggests that the large hole Fermi surface characteristic of the overdoped regime undergoes a reconstruction caused by the onset of some order which breaks translational symmetry. Here we consider the possibility that this order is ``stripe'' order, a form of combined charge / spin modulation observed most clearly in materials like Eu- doped and Nd-doped LSCO. In these materials, the onset of stripe order coincides with major changes in transport properties (3), providing strong evidence that stripe order is indeed the cause of Fermi-surface reconstruction. We identify the critical doping where this reconstruction occurs and show that the temperature dependence of transport coefficients at that doping is typical of metals at a quantum critical point (4). We discuss an interpretation of the pseudogap as a fluctuating precursor of the stripe-ordered phase.This work was performed in collaboration with L. Balicas, D.A. Bonn, J. Chang, O. Cyr-Choinière, R. Daou, N. Doiron- Leyraud, W.N. Hardy, N.E. Hussey, F. Lalibert'e, D. LeBoeuf, S.Y. Li, R. Liang, C. Proust, H. Takagi, and J.S. Zhou.(1) N. Doiron-Leyraud et al., Nature 447, 565 (2007).(2) D. LeBoeuf et al., Nature 450, 533 (2007).(3) R. Daou et al., Nature Physics, in press (DOI 10.1038/nphys1109); http://arXiv.org/abs/0806.2881.(4) R. Daou et al., to be published; http://arXiv.org/abs/0810.4280.

Taillefer, Louis

2009-03-01

388

Generating Decompilers  

Microsoft Academic Search

Compiler compilers are in widespread use, but decompiler compilers are a more novel concept. This paper presents an approach for the decompilation of object code back to source code using a decompiler generator. An example decompilation is presented. Potential applications include reverse engineering, quality assessment, debugging and safety-critical code validation or verification.

Peter T. Breuer; Jonathan P. Bowen

1998-01-01

389

Steam generators  

Microsoft Academic Search

A steam generator is disclosed which is particularly adapted to be used in nuclear power plants. A casing is provided with an inlet and outlet to receive and discharge a primary heating fluid from which heat is to be extracted. A pair of tube plates extend across the interior of the casing at the region of the inlet and outlet

G. Beckmann; P. V. Gilli; K. Fritz; J. Lippitsch

1975-01-01

390

Aerosol Generator.  

National Technical Information Service (NTIS)

The invention pertains to devices for the production of dry aerosol and the treatment of rodent burrows with it. Existing aerosol generators include a fan with an air duct, a muffled engine a guiding pipe, and a control mechanism. In the proposed generato...

B. M. Kasatkin N. V. Kasatkina

1973-01-01

391

Manipulating attentional load in sequence learning through random number generation.  

PubMed

Implicit learning is often assumed to be an effortless process. However, some artificial grammar learning and sequence learning studies using dual tasks seem to suggest that attention is essential for implicit learning to occur. This discrepancy probably results from the specific type of secondary task that is used. Different secondary tasks may engage attentional resources differently and therefore may bias performance on the primary task in different ways. Here, we used a random number generation (RNG) task, which may allow for a closer monitoring of a participant's engagement in a secondary task than the popular secondary task in sequence learning studies: tone counting (TC). In the first two experiments, we investigated the interference associated with performing RNG concurrently with a serial reaction time (SRT) task. In a third experiment, we compared the effects of RNG and TC. In all three experiments, we directly evaluated participants' knowledge of the sequence with a subsequent sequence generation task. Sequence learning was consistently observed in all experiments, but was impaired under dual-task conditions. Most importantly, our data suggest that RNG is more demanding and impairs learning to a greater extent than TC. Nevertheless, we failed to observe effects of the secondary task in subsequent sequence generation. Our studies indicate that RNG is a promising task to explore the involvement of attention in the SRT task. PMID:22723816

Wierzcho?, Micha?; Gaillard, Vinciane; Asanowicz, Dariusz; Cleeremans, Axel

2012-01-01

392

Distribution of orally administered and chronically fed /sup 95m/Tc in Japanese quail tissues and eggs  

SciTech Connect

Previous coefficients for transfer of technetium from feed to poultry have utilized default values. These investigations examined the uptake and distribution of /sup 95m/Tc in male and female Japanese quail following their ingestion of Tc incorporated into alfalfa during growth. Approximately 8% of the daily ingested Tc was transferred to eggs. Biological half-time was one to two days. After 10 days of feeding, 80% of the Tc was in yolk, 20% in albumin, and less than 1% in shell and associated membranes. The Tc levels in albumin reached a maximum between three and five days, compared to six to seven days for yolk. Laying female quail contained 27% of the daily-ingested Tc compared to 5% for males. However, approximately 23% of the daily female Tc intake was contained in the developing ova and reproductive organs. The highest Tc concentrations were in oocytes of laying hens, followed by the fully formed unlaid egg and the ovaries. The uterine shelled egg contained five times the amount of Tc present in other edible tissues combined. For males, the gizzard contained about 53% of the Tc in other edible tissues, followed by muscle (25%), liver (19%), and hea

Thomas, J.M.; Cadwell, L.L.; Garland, T.R.; Cataldo, D.A.

1984-10-01

393

High-Tc nodeless s±-wave superconductivity in (Y,La)FeAsO(1-y) with Tc=50 K:75As-NMR study.  

PubMed

We report on an (75)As-NMR study on the Fe-pnictide high-T(c) superconductor Y(0.95)La(0.05)FeAsO(1-y) (Y(0.95)La(0.05)1111) with T(c)=50 K that includes no magnetic rare-earth elements. The measurement of the nuclear-spin lattice-relaxation rate (75)(1/T(1)) has revealed that the nodeless bulk superconductivity takes place at T(c)=50 K while antiferromagnetic spin fluctuations develop moderately in the normal state. These features are consistently described by the multiple fully gapped s(±)-wave model based on the Fermi-surface nesting. Incorporating the theory based on band calculations, we propose that the reason that T(c)=50 K in Y(0.95)La(0.05)1111 is larger than T(c)=28 K in La1111 is that the Fermi-surface multiplicity is maximized, and hence the Fermi-surface nesting condition is better than that in La1111. PMID:23102353

Mukuda, H; Furukawa, S; Kinouchi, H; Yashima, M; Kitaoka, Y; Shirage, P M; Eisaki, H; Iyo, A

2012-10-12

394

Preoperative determination of the surgical procedure for hepatectomy using technetium-99m-galactosyl human serum albumin ( 99mTc-GSA) liver scintigraphy  

Microsoft Academic Search

Technetium-99m-diethylenetriaminepentaacetic acidgalactosyl human serum albumin (Tc-GSA) is a new liver scintigraphy agent which binds to the asialoglycoprotein receptors. We evaluated the preoperative assessment for hepatectomy using Tc-GSA liver scintigraphy. Ninety patients with hepatocellular carcinoma were admitted for elective hepatectomy. Tc-GSA scintigraphy was conducted after the intravenous injection of Tc-GSA, and maximal removal rate of Tc-GSA (GSA-Rmax) was calculated using a

A Kwon; SK Ha-Kawa; S Uetsuji; T Inoue; Y Matsui; Y Kamiyama

1997-01-01

395

Prevention and Inhibition of TC-1 Cell Growth in Tumor Bearing Mice by HPV16 E7 Protein in Fusion with Shiga Toxin B-Subunit from shigella dysenteriae  

PubMed Central

Objective: For immunotherapy of human papillomavirus (HPV) -16-associated cervical cancers the E7 protein is considered a prime candidate. However it is a poor inducer of cytotoxic T-cell response, when being used as a singular antigen in protein vaccination. Hence, in this study we focused on the utilization of a vaccine delivery system for prevention or treatment of cervical cancer. Materials and Methods: In this experimental study, we designed and evaluated a novel fusion protein comprising HPV16 E7 antigen fused to Shiga toxin B-subunit (STxB) as both an antigen vector and an adjuvant. Then we designed two preventive and therapeutic tumor models to investigate the prevention and inhibition of TC-1 cell growth in female C57BL/6 mice, respectively. In each model, mice were immunized with the recombinant protein of E7-STxB or E7 without any adjuvant. Results: We demonstrated that prophylactic immunization of E7-STxB protected mice against TC-1 cells. Also in the therapeutic model, E7-STxB inhibited TC-1 tumor growth inlungs. The results were significant when compared with the immunization of E7 singularly. Conclusion: We concluded that immunization with the E7-STxB protein without any adjuvant could generate anti-tumor effect in mice challenged with TC-1 cells.This research verifies the clinical applications and the future prospects of developing HPV16 E7 therapeutic vaccines fused to immunoadjuvants.

Sadraeian, Mohammad; Khoshnood Mansoorkhani, Mohammad Javad; Mohkam, Milad; Rasoul-Amini, Sara; Hesaraki, Mahdi; Ghasemi, Younes

2013-01-01

396

Development of more efficacious Tc-99m organ imaging agents for use in nuclear medicine by analytical characterization of radiopharmaceutical mixtures. Progress report, September 1, 1989--January 31, 1992  

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

397

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

398

Technetium-carbon multiple bonds. Synthesis and structure of Tc(=C=CHPh)Cl(dppe)[sub 2] and [Tc([triple bond]C-CH[sub 2]-t-Bu)Cl(dppe)[sub 2  

SciTech Connect

The 16-electron complex TcCl(dppe)[sub 2] reacts with terminal alkynes to form neutral vinylidene complexes of the type Tc(=C=CHR)Cl(dppe)[sub 2] (R = Ph, Me, t-Bu). Treatment of these vinylidene complexes with acid (HBF[sub 4] for R = Ph, HNMe[sub 3]BPh[sub 4] for R = t-Bu) yields the respective terminal carbyne complexes Tc([triple bond]CCH[sub 2]R)-Cl(dppe)[sub 2][sup +] (R = Ph, t-Bu). These vinylidene and carbyne compounds represent the first examples of technetium carbenes or carbynes. X-ray structures of Tc(=C=CHPh)Cl(ddpe)[sub 2] and Tc([triple bond]CCH[sub 2]-t-Bu)Cl(dppe)[sub 2[minus]+] were determined, and the Tc-C bond lengths obtained were 1.861(9) and 1.724(7) A, respectively. 13 refs., 2 figs.

Burrell, A.K.; Bryan, J.C.; Kubas, G.J. (Los Alamos National Lab., NM (United States))

1994-04-01

399

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; Danièle Gardy; Dominique Gouyou-beauchamps

2002-01-01

400

Observation of a New Mechanism of Spontaneous Generation of Magnetic Flux in a Superconductor  

Microsoft Academic Search

We report the discovery of a new mechanism of spontaneous generation of a magnetic flux in a superconductor cooled through Tc. Values of the spontaneous flux appear random from one cooldown to the next, following a Gaussian distribution. The width of the distribution increases with the size of the temperature gradient in the sample. Our observations appear inconsistent with the

Ariel Maniv; Emil Polturak; Gad Koren; Yuri Bliokh; Björn Biehler; Bernd-Uwe Runge; Paul Leiderer; Boris Shapiro; Irena Shapiro

2005-01-01

401

[Regulation of immunological balance between TH1/TH2 and Tc1/Tc2 lymphocytes by prostaglandin E2].  

PubMed

This study was purposed to investigate the effect of prostaglandin E2 (PGE2) on proliferation of peripheral blood T lymphocytes, and to evaluate the regulatory role of PGE2 on immunological balance between Th1/Th2 and Tc1/Tc2 lymphocytes. The peripheral blood mononuclear cells (PBMNC) were stimulated by anti-human CD3 monoclonal antibody (mAb) and anti-human CD28 mAb, and were cultured in the presence of different concentration of PGE2 for 120 hours. The proliferation of peripheral blood T lymphocytes was assayed according to the manufacture protocol of BrdU Kit; the IFN-gamma and IL-4 levels in supernatants cultured for 24, 48, 72 and 120 hours were detected by ELISA; the ratios of CD4+IL-4+ T cells/CD4+ IFN-gamma+ T cells and CD8+IL-4+ T cell/CD8+IFN-gamma+ T cells were determined by flow cytometry. The cells cultured without PGE2 were used as control. The results indicated that (1) with the raising of concentration of PGE2, the inhibitory rate of T cell proliferation in vitro significantly increased (p=0.001). There was significant positive correlation between inhibitory rate of T cells and PGE2 concentration (correlation coefficient=0.889, p=0.000). (2) the difference between the IFN-gamma concentrations in supernatant cultured for 120 and 72 hours in test groups had no statistical significance (p=0.917). The IFN-gamma concentration increased continually with prolonging of culture time in control group (p=0.046). The IFN-gamma concentrations produced at different times in test group were significantly lower compared with those in control group (p<0.05). The IL-4 concentrations produced at different time had no significant change in test groups (p=0.400). The IL-4 concentration in 24 hours in control group was significantly higher than that at 48, 72 and 120 hours in control group (p=0.007, 0.003 and 0.002). After cultured for 24 hours the IL-4 concentration in test group was significantly lower than that in control group (p=0.037), but after cultured for 48, 72 and 120 hours, the IL-4 concentration in test group did not show statistical difference in comparison with control group (p>0.05). (3) the proportions of CD4+IFN-gamma+T cells in test group and in control group had no significant difference (p=0.767). The proportion of CD4+IL-4+T cells in test group was slightly higher than that in control group (p=0.051). The ratio of CD4+IL-4+T cells to CD4+IFN-gamma+ T cells in test group was significantly higher than that in control group (p=0.011). The proportions of CD8+IFN-gamma+ T cells in test group and in control group had no statistical difference (p=0.441). The proportion of CD8+IL-4+T cells in test group was significantly higher than that in control group (p=0.015). The ratio of CD8+IL-4+ T cells to CD8+IFN-gamma+ T cells in test group were obviously higher than that in control group(p=0.038). It is concluded that the PGE2 inhibits the proliferation of T lymphocytes in vitro. PGE2 influences the production of IFN-gamma and IL-4, and significantly influences peak appearance of IFN-gamma produced by T lymphocyte. PGE2 can continuously inhibit the production of IFN-gamma, but its continuous effect on IL-4 is no significant. PGE2 enhances the ratio of CD4+IL-4+T lymphocytes to CD4+IFN-gamma+T lymphocytes and the ratio of CD8+IL-4+T lymphocytes to CD8+IFN-gamma+T lymphocytes, and regulates development of T cells toward Th2/Tc2 cells. PMID:20416182

Bao, Yu-Shi; Wang, Mei; Zhang, Ping; Zhou, Zhen; Zhai, Wen-Jing; Wang, Hua; Jiang, Er-Lie; Huang, Yong; Feng, Si-Zhou; Han, Ming-Zhe

2010-04-01

402

Photon generator  

DOEpatents

A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

Srinivasan-Rao, Triveni (Shoreham, NY)

2002-01-01

403

Protein profiles in Tc1 mice implicate novel pathway perturbations in the Down syndrome brain.  

PubMed

Tc1 mouse model of Down syndrome (DS) is functionally trisomic for ?120 human chromosome 21 (HSA21) classical protein-coding genes. Tc1 mice display features relevant to the DS phenotype, including abnormalities in learning and memory and synaptic plasticity. To determine the molecular basis for the phenotypic features, the levels of 90 phosphorylation-specific and phosphorylation-independent proteins were measured by Reverse Phase Protein Arrays in hippocampus and cortex, and 64 in cerebellum, of Tc1 mice and littermate controls. Abnormal levels of proteins involved in MAP kinase, mTOR, GSK3B and neuregulin signaling were identified in trisomic mice. In addition, altered correlations among the levels of N-methyl-D-aspartate (NMDA) receptor subunits and the HSA21 proteins amyloid beta (A4) precursor protein (APP) and TIAM1, and between immediate early gene (IEG) proteins and the HSA21 protein superoxide dismutase-1 (SOD1) were found in the hippocampus of Tc1 mice, suggesting altered stoichiometry among these sets of functionally interacting proteins. Protein abnormalities in Tc1 mice were compared with the results of a similar analysis of Ts65Dn mice, a DS mouse model that is trisomic for orthologs of 50 genes trisomic in the Tc1 plus an additional 38 HSA21 orthologs. While there are similarities, abnormalities unique to the Tc1 include increased levels of the S100B calcium-binding protein, mTOR proteins RAPTOR and P70S6, the AMP-kinase catalytic subunit AMPKA, the IEG proteins FBJ murine osteosarcoma viral oncogene homolog (CFOS) and activity-regulated cytoskeleton-associated protein (ARC), and the neuregulin 1 receptor ERBB4. These data identify novel perturbations, relevant to neurological function and to some seen in Alzheimer's disease, that may occur in the DS brain, potentially contributing to phenotypic features and influencing drug responses. PMID:23349361

Ahmed, Md Mahiuddin; Dhanasekaran, A Ranjitha; Tong, Suhong; Wiseman, Frances K; Fisher, Elizabeth M C; Tybulewicz, Victor L J; Gardiner, Katheleen J

2013-05-01

404

Experimental study of 99mTc-depreotide preparation and its affinity with A549 cell.  

PubMed

The (99m)Tc-labeled agent, ((99m)TcO)depreotide, has received regulatory approval in the United States and Europe for use in the detection of cancer. It is essential to establish a simple and reliable method of direct radiolabeling of (99m)Tc-depreotide and to investigate its specific receptor binding properties with human non small cell lung cancer (NSCLC) A549 cell in vitro. So we made some researches as follow: Depreotide was labeled with (99m)Tc using SnCl2 as a reductant. Labeling efficiencies at different pH values and temperatures were compared. Radioreceptor assay was used to observe the uptake kinetics, stagnation and retention half time of (99m)Tc-depreotide in A549 cells. As the results of the investigation ,many facts is shown below: The labeling rate of pH 6.0 group was higher than that of pH 5.0 and pH7.0 groups. The labeling rate decreased when temperature increased from 15 °C to 50 °C. The uptake rate increased with rising temperature, and the maximum uptake was observed at 60 min at 37 °C. The cleaning curves were similar at different temperatures, and the half cleaning time at 37 °C was 48 min. The results showed that the optimal conditions for labeling depreotide with (99m)Tc was found to be below 15 °C at a pH lower than 6.0. Furthermore, at 37 °C, (99m)Tc-depreotid may have the potential as an ideal imaging agent for somatostatin receptors. PMID:21622193

Xia, Wei; Zhang, Xiaoping; Yu, Fei; Wang, Peijun; Cai, Haidong; Hou, Renhua; Wang, Guoyu; Yuan, Xueyu; LV, Zhongwei

2011-01-01

405

Diagnostic Performance of an Expert System for Interpretation of 99mTc MAG3 Scans in Suspected Renal Obstruction  

PubMed Central

The purpose of the study was to compare diuresis renography scan interpretation generated by a renal expert system with the consensus interpretation of 3 expert readers. Methods The expert system was evaluated in 95 randomly selected furosemide-augmented patient studies (185 kidneys) obtained for suspected obstruction; there were 55 males and 40 females with a mean age ± SD of 58.6 ± 16.5 y. Each subject had a baseline 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) scan followed by furosemide administration and a separate 20-min acquisition. Quantitative parameters were automatically extracted from baseline and furosemide acquisitions and forwarded to the expert system for analysis. Three experts, unaware of clinical information, independently graded each kidney as obstructed/probably obstructed, equivocal, and probably nonobstructed/nonobstructed; experts resolved differences by a consensus reading. These 3 expert categories were compared with the obstructed, equivocal, and nonobstructed interpretations provided by the expert system. Agreement was assessed using weighted ?, and the predictive accuracy of the expert system compared with expert readers was assessed by the area under receiver-operating-characteristic (ROC curve) curves. Results The expert system agreed with the consensus reading in 84% (101/120) of nonobstructed kidneys, in 92% (33/36) of obstructed kidneys, and in 45% (13/29) of equivocal kidneys. The weighted ? between the expert system and the consensus reading was 0.72 and was comparable with the weighted ? between experts. There was no significant difference in the areas under the ROC curves when the expert system was compared with each expert using the other 2 experts as the gold standard. Conclusion The renal expert system showed good agreement with the expert interpretation and could be a useful educational and decision support tool to assist physicians in the diagnosis of renal obstruction. To better mirror the clinical setting, algorithms to incorporate clinical data must be designed, implemented, and tested.

Taylor, Andrew; Garcia, Ernest V.; Binongo, Jose Nilo G.; Manatunga, Amita; Halkar, Raghuveer; Folks, Russell D.; Dubovsky, Eva

2011-01-01

406

ECT imaging with Tc(V)-99m dimercaptosuccinic acid useful to detect lung metastases of osteosarcoma  

SciTech Connect

ECT imaging, using Tc(V)-99m dimercaptosuccinic acid (Tc(V)-DMS) was performed in two patients with lung metastasis of osteosarcoma, and the results were compared with those of CT scan. Clear accumulation of Tc(V)-DMS was recognized in all cases in the same area that CT scans demonstrated. Tc(V)-DMS was labeled under optimal pH 8, had very low SnCl/sub 2/ concentrations, an equilibrium between a stable form and a dissociated form of anion TcO/sub 4/(3-) structurally similar to PO/sub 4/(3-), and was postulated for tumor uptake. Considering this proposed mechanism for Tc(V)-DMS uptake by tumor cells, ECT imaging using this tracer could be of use in the early detection of lung metastasis of osteosarcoma.

Ohta, H.; Ishii, M.; Yoshizumi, M.; Endo, K.; Fujita, T.; Nakajima, T.; Sakahara, H.; Torizuka, K.; Kotoura, Y.; Yokoyama, A.

1985-01-01

407

Preparation and Characterization of TlBa2Ca2Cu3Oy with a Different Maximum Tc  

NASA Astrophysics Data System (ADS)

We have succeeded to prepare Tl-1223 samples with a maximum Tc above 130K at ambient pressure using a conventional sealed quartz tube method. We found that, by adequately controlling the starting composition, it is possible to control the maximum Tc from ~120K to 130K. In order to seek the key factors for a drastic increase in the Tc, we carried out the measurements of the thermoelectric power, powder X-ray diffraction and neutron diffraction for these samples. As a result, it is found that the characteristics in the Tl-1223 samples with high Tc show essentially similar to those in the Hg-1223 with the highest Tc and are different from those in the Tl-1223 samples with low Tc. The details of the synthesis conditions, the transport properties and the refinements of the crystal structure will be presented.

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

408

In vitro and in vivo characterization of a 99mTc complex with tris(hydroxymethyl)phosphine (THP)  

Microsoft Academic Search

The water-soluble, monophosphine ligand tris(hydroxymethyl)phosphine (THMP) was complexed with 99mTc. The 99mTc-THMP was formed in high radiochemical purity by simply mixing 99mTcO4? with THMP over a wide pH range. In vitro and in vivo studies indicated the complex to be highly stable under the respective conditions. HPLC analysis indicated a singular species with a retention time identical to the known

D. E. Berning; K. V. Katti; P. R. Singh; C. Higgenbotham; V. Sreenivasa Reddy; W. A. Volkert

1996-01-01

409

The High-Tc Superconducting State of ?-(BEDT-TTF)2I3 at Atmospheric Pressure: Bulk Superconductivity and Metastability  

Microsoft Academic Search

The AC susceptibility study of ?-(BEDT-TTF)2I3 reveals that the high-Tc metastable superconducting state which can be stabilized at atmospheric pressure after a particular pressure-temperature cycling procedure, exhibits bulk superconductivity resembling very closely that of the high-Tc state, which is stabilized above 1 kbar. Annealing experiments show that the high-Tc state remains stable at low temperature as long as the annealing

F. Creuzet; D. Jerome; D. Schweitzer; H. J. Keller

1986-01-01

410

99m Tc-DTPA dynamic SPECT and CT volumetry for measuring split renal function in live kidney donors  

Microsoft Academic Search

Objectives  Split renal function (SRF) estimated from the posterior view of 99mTc-diethylenetriaminepentaacetic acid planar scintigraphy (DTPA\\/P) is not sufficiently accurate even after correction for\\u000a kidney depth by computed tomography (CT). To obtain more accurate SRF using 99mTc-DTPA, dynamic SPECT method was carried out for the initial 5 min after bolus injection of 99mTc-DTPA (DTPA\\/SPECT). Also SRF was evaluated from the renal volume

Chihoko Miyazaki; Hiroshi Harada; Noriyuki Shuke; Atsutaka Okizaki; Masayoshi Miura; Tetsuo Hirano

2010-01-01

411

Tide generator  

SciTech Connect

A tidewater power system consisting of a high tide reservoir and a low tide reservoir. The high tide reservoir has an inlet adapted to be supported at high tide level and an outlet with a water wheel and generator between the outlet of the high tide reservoir and the low tide reservoir. The low tide reservoir has an outlet at the low tide level. The outlet from the high tide reservoir is adjustable to control the flow rate and the high tide reservoir can be closed at high tide to retain water for use over a period of time.

Feltenberger, B.D.

1981-06-16

412

Piezoelectrostatic generator  

NASA Technical Reports Server (NTRS)

A piezoelectrostatic generator includes a plurality of elongated piezoelectric elements having first and second ends, with the first ends fixedly mounted in a cylindrical housing and the second extending radially inwardly toward an axis. A shaft movable along the axis is connected to the inner ends of the elements to produce bending forces in piezoelectric strips within the elements. Each element includes a pair of strips mounted in surface contact and in electrical series to produce a potential upon bending. Electrodes spaced from the strips by a solid dielectric material act as capacitor plates to collect the potential charge.

Robertson, Glen A. (inventor)

1990-01-01

413

Spontaneous generation  

NSDL National Science Digital Library

This lesson demonstrates that scientific knowledge is stable, but also prone to change. Students will understand how those changes can happen in the context of the history of spontaneous generation. This lesson from the American Association for the Advancement of Science aligns with Benchmarks 1 and 10, Nature of Science, and History of Science. It can be done as a class or via student independent study. Part of the lesson involves students accessing related information on the Internet. Thorough teacher background information and pedagogically sound, structured discussion questions are provided.

2001-01-01

414

Solvent extraction of [sup 99]Tc from radioactive intermediate liquid waste by dibenzo-18-crown-6.  

SciTech Connect

Technetium is one of the most prominent problems since its most stable specie in the environment, the pertechnetate ion, is highly mobile and considered as a long-term hazard in nuclear waste disposal. Because of the small activities of 99Tc relative to other fission products 137Cso r 90Sr,a nd its long half-life time (t1/2 = 2.1{center_dot}10{sup 5} yrs), 99Tci s one of the key isotopes that should always be analyzed in the radioactive liquid waste streams from the reprocessing industry where the largest concentrations are to be expected. Furthermore, as a pure beta-emitter, Tc has to be isolated from the intermediate level waste (ILW) stream prior to any measurement in such complex media. We have developed a method for 99Tc extraction providing recommendations that will be useful for extracting it from acid and basic ILW. The extraction of 99Tc from L W by dibenzo-18-crown-6 (DB18C6) has been investigated and a simplex optimization of key parameters involved in the procedure has allowed us to set up their best values. Experiments have been carried out on synthetic and real effluents from La Hague reprocessing plant, France, and results show that DB18C6 is highly selective towards 99Tc. The application of this procedure has been successfully demonstrated through the analysis of actual waste streams coming from two reprocessing plants at La Hague and Marcoule, France.

Paviet-Hartmann, P. (Patricia)

2001-01-01

415

Tc17 CD8+ T cells potentiate Th1-mediated autoimmune diabetes in a mouse model.  

PubMed

An increase in IL-17-producing CD8+ T (Tc17) cells has been reported in the peripheral blood of children with recent onset type 1 diabetes (T1D), but their contribution to disease pathogenesis is still unknown. To directly study the pathogenic potential of ? cell-specific Tc17 cells, we used an experimental model of T1D based on the expression of the neo-self Ag hemagglutinin (HA) in the ? cells of the pancreas. When transferred alone, the IL-17-producing HA-specific CD8+ T cells homed to the pancreatic lymph nodes without causing any pancreatic infiltration or tissue destruction. When transferred together with small numbers of diabetogenic HA-specific CD4+ T cells, a strikingly different phenotype developed. Under these conditions, Tc17 cells sustained disease progression, driving the destruction of ?-islet cells, causing hyperglycemia and ultimately death. Disease progression did not correlate with functional or numerical alterations among the HA-specific CD4+ T cells. Rather, the transferred CD8+ T cells accumulated in the pancreatic islets and a considerable fraction converted, under the control of IL-12, to an IFN-?-producing phenotype. Our data indicate that Tc17 cells are not diabetogenic but can potentiate a Th1-mediated disease. Plasticity of the Tc17 lineage is associated with transition to overt disease in this experimental model of T1D. PMID:22904307

Saxena, Amit; Desbois, Sabine; Carrié, Nadège; Lawand, Myriam; Mars, Lennart T; Liblau, Roland S

2012-09-15

416

Bradykinin ?2 Receptor -58T/C Gene Polymorphism and Essential Hypertension: A Meta-Analysis  

PubMed Central

Background Research has shown that bradykinin ?2 receptor (BDKRB2) ?58T/C gene polymorphism is correlated with the risk of essential hypertension (EH), but the results remain inconclusive. Objective and Methods The objective of this study was to explore the association between BDKRB2?58T/C gene polymorphism and EH. A meta-analysis of 11 studies with 3882 subjects was conducted. Pooled odds ratios (ORs) for the association between BDKRB2?58T/C gene polymorphism and EH and their corresponding 95% confidence intervals (CIs) were estimated using the random effects model. Results The BDKRB2?58T/C gene polymorphism was significantly correlated with EH under an allelic genetic model (OR?=?1.24, 95% CI?=?1.05–1.46; P?=?0.01), a dominant genetic model (OR?=?0.65, 95% CI?=?0.47–0.90; P?=?0.01), a recessive genetic model (OR?=?1.146, 95% CI?=?1.035–1.269; P?=?0.009), a homozygote genetic model (OR?=?1.134, 95% CI?=?1.048–1.228; P?=?0.002), and a heterozygote genetic model (OR?=?1.060, 95% CI?=?1.009–1.112; P?=?0.019). Conclusions The BDKRB2?58T/C gene polymorphism is associated with increased EH risk. The results of this study suggest that carriers of the ?58C allele are susceptible to EH.

Li, Yan-yan; Zhang, Hui; Xu, Jian; Qian, Yun; Lu, Xin-zheng; Yang, Bing; Chen, Minglong; Yang, Zhi-jian; Cao, Ke-jiang

2012-01-01

417

Technetium-99m galactosyl-neoglycoalbumin (Tc-NGA) liver imaging: Application in liver transplantation  

SciTech Connect

Tc-NGA is a new liver imaging agent which binds to hepatic binding protein (HBP), a hepatocyte-specific membrane receptor. The purpose of the present study was to evaluate the potential role of Tc-NGA imaging in liver transplantation. The molar Tc-NGA dose was standardized according to patient weight (0.7 nmole/kg). After a 30 minute dynamic imaging study (5 mCi, IV), kinetic analysis of time activity data (heart, liver), provided values for receptor concentration, (HBP), and hepatic blood flow, Q. Eleven Tc-NGA imaging studies were performed in transplant candidates and 22 studies were performed in seven transplant recipients. Preservation damage was manifested by diffuse patchiness in tracer distribution which resolved during the following two weeks. Histologically proven, localized hepatic infarcts were demonstrated in three recipients. Lobar infarction was demonstrated in one recipient. Hepatic regeneration was later demonstrated in this patient after hepatic lobectomy. Hepatic blood flow was markedly decreased in the early postoperative period, but improved with time. Increased (HBP) was demonstrated with regeneration. Markedly decreased (HBP) and Q were obtained in several candidates who died awaiting transplantation. These studies indicate that TC-NGA liver imaging provides a valuable new means for: (1) evaluation of preservation damage, (2) early demonstration of hepatic infarction, (3) evaluation of hepatic rejection, and (4) selection of patients for hepatic transplantation.

Woodle, E.S.; Ward, R.E.; Vera, D.R.; Stadalnik, R.C.

1985-05-01

418

Blood flow and bone uptake of /sup 99m/Tc-labeled methylene diphosphonate  

SciTech Connect

In mature dogs with comparable levels of bone remodeling, we produced either increased (with adenosine triphosphate) or decreased (with epinephrine) blood flow to one hindlimb. In 13 dogs (five control, four with increased flow, and four with decreased flow), we compared uptake, at 3 h after injection of radiolabeled diphosphonate in the mid-tibia, with blood flow as determined by microspheres. Blood flow was determined with /sup 85/Sr-labeled microspheres, and determination of uptake of /sup 99m/Tc methylene diphosphonate (/sup 99m/Tc-MDP) was by a gamma detector. There was a linear relationship between changes in diphosphonate uptake and changes in blood flow at decreased and normal flows; however, at high flows the relationship was nonproportional, indicating a disproportionately slower increase in /sup 99m/Tc-MDP uptake with increasing blood flow. In six dogs an initial 1-h uptake curve of /sup 99m/Tc-MDP was determined in both control and experimental limbs under states of increased and decreased blood flow. The 30-min uptake value, 60-min uptake value, area under the curve, and the slope of the curve were related to flow as determined by microspheres. The data are consistent with the hypothesis that deposition of bone-concentrating isotopes such as /sup 99m/Tc-MDP is partly controlled by blood flow; at supranormal and normal flows tracer uptake is closely related to blood flow, but at supranormal flow rates it is not and appears to be diffusion limited.

Riggs, S.A.; Wood, M.B.; Cooney, W.P.; Kelly, P.J.

1984-01-01

419

Chemical aspects of labeling sucralfate with /sup 99m/TcO/sub 4/  

SciTech Connect

Two formulations of (/sup 99m/Tc)sucralfate have been used to image gastric and duodenal ulcers and inflammatory bowel disease. One formulation is a complexation of (/sup 99m/Tc)HSA with sucralfate. The second is prepared by directly labeling sucralfate with (/sup 99m/Tc)pertechnetate in the presence of stannous ion. An in vitro study of the factors affecting the production and stability of these labeled sucralfate preparations was conducted. Both formulations were stable at the acidic pH likely encountered in the stomach. However, at pH greater than 6 the albumin-sucralfate complex began to dissociate while directly labeled sucralfate was stable to a pH of 9. Conversely it was shown that directly labeled sucralfate was more susceptible to loss of /sup 99m/Tc to other chelating species. Sucralfate complexed with (/sup 99m/Tc)HSA was radiochemically stable up to a specific activity of 26 GBq (700 mCi) per gram while directly labeled sucralfate showed decreased 24-hr stability at specific activities greater than 837 mCi (31 GBq) per gram.

Billinghurst, M.W.; Abrams, D.N.; Lawson, M.S.

1989-04-01

420

Characteristic two-dimensional Fermi surface topology of high-Tc iron-based superconductors  

NASA Astrophysics Data System (ADS)

Unconventional Cooper pairing originating from spin or orbital fluctuations has been proposed for iron-based superconductors. Such pairing may be enhanced by quasi-nesting of two-dimensional electron and hole-like Fermi surfaces (FS), which is considered an important ingredient for superconductivity at high critical temperatures (high-Tc). However, the dimensionality of the FS varies for hole and electron-doped systems, so the precise importance of this feature for high-Tc materials remains unclear. Here we demonstrate a phase of electron-doped CaFe2As2 (La and P co-doped CaFe2As2) with Tc = 45 K, which is the highest Tc found for the AEFe2As2 bulk superconductors (122-type; AE = Alkaline Earth), possesses only cylindrical hole- and electron-like FSs. This result indicates that FS topology consisting only of two-dimensional sheets is characteristic of both hole- and electron-doped 122-type high-Tc superconductors.

Sunagawa, Masanori; Ishiga, Toshihiko; Tsubota, Koji; Jabuchi, Taihei; Sonoyama, Junki; Iba, Keita; Kudo, Kazutaka; Nohara, Minoru; Ono, Kanta; Kumigashira, Hiroshi; Matsushita, Tomohiro; Arita, Masashi; Shimada, Kenya; Namatame, Hirofumi; Taniguchi, Masaki; Wakita, Takanori; Muraoka, Yuji; Yokoya, Takayoshi

2014-03-01