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1

An electrochemical procedure to concentrate 99mTc availed from a zirconium [99Mo] molybdate gel generator.  

PubMed

Successful use of electrochemical method to concentrate (99m)Tc obtained from a zirconium molybdate (Zr(99)Mo) gel generator is reported. The process consists of electrodeposition of the (99m)Tc in an oxalate bath on a small platinum electrode followed by recovery of (99m)Tc in a small volume of normal saline. The overall recovery of (99m)Tc was >90% with >99.99% radionuclidic purity and >99% radiochemical purity. The compatibility of the product in the preparation of (99m)Tc labeled formulations such as (99m)Tc-DMSA and (99m)Tc-EC was found to be satisfactory in terms of high labeling yields (>98%). PMID:22036305

Chakravarty, Rubel; Sarkar, S K; Venkatesh, Meera; Dash, Ashutosh

2012-02-01

2

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

3

Computed tomography image using sub-terahertz waves generated from a high-Tc superconducting intrinsic Josephson junction oscillator  

NASA Astrophysics Data System (ADS)

A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-Tc superconductor Bi2Sr2CaCu2O8+? was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.

Kashiwagi, T.; Nakade, K.; Saiwai, Y.; Minami, H.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y.; Tsujimoto, M.; Yamamoto, T.; Markovi?, B.; Mirkovi?, J.; Klemm, R. A.; Kadowaki, K.

2014-02-01

4

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

Microsoft Academic Search

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

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

2010-01-01

5

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

PubMed Central

Purpose of the Study: The indigenous design and technology development for processing large scale zirconium molybdate-Mo-99 (ZrMo-99) Geltech generator was successfully commissioned in Board of Radiation and Isotope Technology (BRIT), India, in 2006. The generator production facility comprises of four shielded plant facilities equipped with tongs and special process gadgets amenable for remote operations for radiochemical processing of ZrMo-99 gel. Results: Over 2800 Geltech generators have been processed and supplied to user hospitals during the period 2006-2013. Geltech generator supplied by BRIT was initially not sterile. Simple elution of Tc-99m is performed by a sterile evacuated vial with sterile and pyrogen free 0.9% NaCl solution to obtain sodium (Tc-99m) pertechnetate solution. A special type online 0.22 ?m membrane filter has been identified and adapted in Geltech generator. Conclusions: The online filtration of Tc-99m from Geltech generator; thus, provided sterile Tc-99m sodium pertechnetate solution. Generators assembled with modified filter assembly were supplied to local hospital in Mumbai Radiation Medicine Centre (RMC) and S.G.S. Medical College and KEM Hospital) and excellent performances were reported by users. PMID:24163509

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

2013-01-01

6

Generation of ultrasonic waves by ac magnetic fields in the mixed state of high-Tc superconductors  

Microsoft Academic Search

We discuss the interaction of a vortex array in a superconductor with sound oscillations, taking into account pinning forces between vortices and crystal displacements. The generation of ultrasound by an ac electromagnetic field acting on the vortex array is considered. We find that at low temperatures and in the linear regime the amplitude of the induced sound wave is proportional

D. Domínguez; L. Bulaevskii; B. Ivlev; M. Maley; A. R. Bishop

1995-01-01

7

Development and production of second generation high Tc superconducting tapes at SuperOx and first tests of model cables  

NASA Astrophysics Data System (ADS)

The SuperOx and SuperOx Japan LLC companies were founded with the goal of developing a cost-effective technology for second generation HTS (2G HTS) tapes by utilizing a combination of the most advanced chemical and physical deposition techniques, together with implementing original tape architectures. In this paper we present a brief overview of our production and experimental facilities and recent results of 2G HTS tape fabrication, and describe the first tests of the tapes in model cables for AC and DC power application.

Lee, S.; Petrykin, V.; Molodyk, A.; Samoilenkov, S.; Kaul, A.; Vavilov, A.; Vysotsky, V.; Fetisov, S.

2014-04-01

8

Generation of ultrasonic waves by ac magnetic fields in the mixed state of high-Tc superconductors  

NASA Astrophysics Data System (ADS)

We discuss the interaction of a vortex array in a superconductor with sound oscillations, taking into account pinning forces between vortices and crystal displacements. The generation of ultrasound by an ac electromagnetic field acting on the vortex array is considered. We find that at low temperatures and in the linear regime the amplitude of the induced sound wave is proportional to the applied dc magnetic field and independent of pinning strength. We show how the subsequent multiple echo amplitudes allow one to obtain information on the Magnus force and viscosity of the vortex array.

Domínguez, D.; Bulaevskii, L.; Ivlev, B.; Maley, M.; Bishop, A. R.

1995-06-01

9

{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

10

Insertion and excision of Caenorhabditis elegans transposable element Tc1.  

PubMed

The transposable element Tc1 is responsible for most spontaneous mutations that occur in Caenorhabditis elegans variety Bergerac. We investigated the genetic and molecular properties of Tc1 transposition and excision. We show that Tc1 insertion into the unc-54 myosin heavy-chain gene was strongly site specific. The DNA sequences of independent Tc1 insertion sites were similar to each other, and we present a consensus sequence for Tc1 insertion that describes these similarities. We show that Tc1 excision was usually imprecise. Tc1 excision was imprecise in both germ line and somatic cells. Imprecise excision generated novel unc-54 alleles that had amino acid substitutions, amino acid insertions, and, in certain cases, probably altered mRNA splicing. The DNA sequences remaining after Tc1 somatic excision were the same as those remaining after germ line excision, but the frequency of somatic excision was at least 1,000-fold higher than that of germ line excision. The genetic properties of Tc1 excision, combined with the DNA sequences of the resulting unc-54 alleles, demonstrated that excision was dependent on Tc1 transposition functions in both germ line and somatic cells. Somatic excision was not regulated in the same strain-specific manner as germ-line excision was. In a genetic background where Tc1 transposition and excision in the germ line was not detectable, Tc1 excision in the soma still occurred at high frequency. PMID:2832734

Eide, D; Anderson, P

1988-02-01

11

High Tc bolometers  

Microsoft Academic Search

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,

P. L. Richards; J. Clarke; Q. Hu; R. Leoni; Ph. Lerch; M. Nahum; S. Verghese; M. R. Beasley; T. H. Geballe; R. H. Hammond; P. Rosenthal; S. R. Spielman; K. Char; B. F. Cole; N. Newman; S. A. Sachtjen

1991-01-01

12

Sustained availability of 99mTc: possible paths forward.  

PubMed

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

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

2013-02-01

13

The Tribolium castaneum cell line TcA: a new tool kit for cell biology  

PubMed Central

The red flour beetle, Tribolium castaneum, is an agriculturally important insect pest that has been widely used as a model organism. Recently, an adherent cell line (BCIRL-TcA-CLG1 or TcA) was developed from late pupae of the red flour beetle. Next generation transcriptome sequencing of TcA cells demonstrated expression of a wide variety of genes associated with specialized functions in chitin metabolism, immune responses and cellular and systemic RNAi pathways. Accordingly, we evaluated the sensitivity of TcA cells to dsRNA to initiate an RNAi response. TcA cells were highly sensitive to minute amounts of dsRNA, with a minimum effective dose of 100?pg/mL resulting in significant suppression of gene expression. We have also developed a plasmid containing two TcA-specific promoters, the promoter from the 40S ribosomal protein subunit (TC006550) and a bi-directional heat shock promoter (TcHS70) from the intergenic space between heat shock proteins 68a and b. These promoters have been employed to provide high levels of either constitutive (TC006550) or inducible (TcHS70) gene expression of the reporter proteins. Our results show that the TcA cell line, with its sensitivity to RNAi and functional TcA-specific promoters, is an invaluable resource for studying basic molecular and physiological questions. PMID:25354547

Silver, Kristopher; Jiang, Hongbo; Fu, Jinping; Phillips, Thomas W.; Beeman, Richard W.; Park, Yoonseong

2014-01-01

14

Design and performance of an automated radionuclide separator: its application on the determination of ??Tc in groundwater.  

PubMed

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

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

2013-11-01

15

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

16

Differential Activation of CD8+ Tumor-Specific Tc1 and Tc2 Cells by an IL-10-Producing Murine Plasmacytoma  

PubMed Central

The involvement of counteractive CD8+ T-cell subsets during tumor-specific immune responses was analyzed in a syngeneic murine plasmacytoma model. CD8+ Tc cells against the immunogenic IL-10-producing BALB/c plasmacytoma ADJ-PC-5 can be easily induced by immunization of BALB/c mice with X-irradiated ADJ-PC-5 tumor cells in vivo and in vitro. However, the failure of recipient mice to mount a protective Tc response against the tumor during early stages of a real or simulated tumor growth is not due to immunological ignorance, but depends on the induction of tumor-specific tolerance, involving a population of tumorinduced CD8+ T cells that are able to inhibit the generation of tumor-specific Tc cells in a primary ADJ-PC-5-specific MLTC, using IFN-? as a suppressive factor. Whereas most longterm cultivated CD8+ ADJ-PC-5-specific Tc lines produce type-1 cytokines on stimulation, at least two of them, which were derived from a primary MLTC, display a type-2 cytokine spectrum. Furthermore, the primary in vitro Tc response against ADJ-PC-5 cells shows characteristics of a Tc2 response. The Tc response is strictly depending on tumor-derived IL-10. CD8+ Tc cells that are induced in a primary MLTC do not produce IFN-?, and the tumor-specific Tc response is enhanced by IL-4 but suppressed by IFN-? or IL-12. In contrast, ADJ-PC- 5-specific CD8+ Tc cells from immunized mice are IFN-? producing Tc1 cells. Since the primary in vitro Tc response against the tumor is suppressed even by the smallest numbers of irradiated ADJ-PC-5-specific Tc1 cells via IFN-? these Tc1 cells behave similar to the suppressive CD8+ T cells that are induced during early stages of ADJ-PC-5 tumorigenesis. PMID:9814607

Pauels, Hans-Gerd; Becker, Christian; Kölsch, Eckehart

1998-01-01

17

Cluster glass behavior of layered manganite above T_C  

NASA Astrophysics Data System (ADS)

It was reported that layered manganite La_1.2Sr_1.8Mn_2O_7(327-phase) shows magnetic phase transition at T_c=128K, and couple of more traces of transitions over T_c, which are believed to be due to intergrowth of (La,Sr)MnO_3(113-phase). Mn NMR spectrum clearly shows two separate peaks coming from the 327-phase and 113-phase. The signal intensity generated by the 327-phase does not vanish above T_c, meaning that the ferromagnetic metallic clusters of 327-phase exists above T_c. Most abnormal feature of this material is that La NMR signal intensity decreases very slowly as the temperature increases from below Tc to above T_c, where the decay time is about 30 minute. Such anormalous behaviors can be explained by the cluster glass model where the interactions between the ferromagnetic clusters of the 113-phase mediated by the 327-phase are frustrated.

Lee, Kyunglim; Kim, Ilryong; Lee, Soonchil

2001-03-01

18

Impedance Magnetocardiography using High-Tc SQUIDs  

NASA Astrophysics Data System (ADS)

We report on Impedance Magnetocardiography (IMCG) measurements using High-Tc SQUID magnetometers in an unshielded environment. A low amplitude high frequency ac current is passed through the body through outer electrodes. Variations in blood flow during the cardiac cycle generate currents that give rise to time varying magnetic fields. Potential applications related to blood flow include imaging of blood perfusion in the myocardium, the detection of pulmonary embolisms (PE's), and studies of the effects of anticoagulants on PE's. An electromagnetic model is used to predict the SQUID response to changes in tissue conductivity and blood volume during the cardiac cycle.

Vajrala, V.; Nawarathna, D.; Claycomb, J. R.; Prodan Miller, C., Jr.

2003-03-01

19

Evaluation of excitation functions of 100Mo(p,d+pn)99Mo and 100Mo (p,2n)99mTc reactions: Estimation of long-lived Tc-impurity and its implication on the specific activity of cyclotron-produced (99m)Tc.  

PubMed

Excitation functions were calculated by the code TALYS for 10 proton-induced reactions on (100)Mo. For (100)Mo(p,d+pn)(99)Mo and (100)Mo(p,2n)(99m)Tc, calculations were also performed using the code STAPRE. Furthermore, for those two reactions and (nat)Mo(p,x)(96)Tc, evaluation of available experimental data was also carried out. The production of (99m)Tc via the (100)Mo(p,2n)-process is discussed. The ratio of atoms of long-lived (99g)Tc and (98)Tc to those of (99m)Tc is appreciably higher in cyclotron production than in generator production of (99m)Tc; this may adversely affect the preparation of (99m)Tc-chelates. PMID:24389533

Qaim, S M; Sudár, S; Scholten, B; Koning, A J; Coenen, H H

2014-02-01

20

Implementation of Multi-Curie Production of 99mTc by Conventional Medical Cyclotrons.  

PubMed

(99m)Tc is currently produced by an aging fleet of nuclear reactors, which require enriched uranium and generate nuclear waste. We report the development of a comprehensive solution to produce (99m)Tc in sufficient quantities to supply a large urban area using a single medical cyclotron. PMID:24722529

Bénard, François; Buckley, Kenneth R; Ruth, Thomas J; Zeisler, Stefan K; Klug, Julius; Hanemaayer, Victoire; Vuckovic, Milan; Hou, Xinchi; Celler, Anna; Appiah, Jean-Pierre; Valliant, John; Kovacs, Michael S; Schaffer, Paul

2014-04-10

21

GASIFICATION TEST RUN TC06  

SciTech Connect

This report discusses test campaign TC06 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 TC06. Test run TC06 was started on July 4, 2001, and completed on September 24, 2001, with an interruption in service between July 25, 2001, and August 19, 2001, due to a filter element failure in the PCD caused by abnormal operating conditions while tuning the main air compressor. The reactor temperature was varied between 1,725 and 1,825 F at pressures from 190 to 230 psig. In TC06, 1,214 hours of solid circulation and 1,025 hours of coal feed were attained with 797 hours of coal feed after the filter element failure. Both reactor and PCD operations were stable during the test run with a stable baseline pressure drop. Due to its length and stability, the TC06 test run provided valuable data necessary to analyze long-term reactor operations and to identify necessary modifications to improve equipment and process performance as well as progressing the goal of many thousands of hours of filter element exposure.

Southern Company Services, Inc.

2003-08-01

22

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

23

Mental Health and the TC. Chapter 5.  

ERIC Educational Resources Information Center

This document contains 19 papers from the ninth World Conference of Therapeutic Communities (TCs) that deal with the interface between the mental health establishments and the TC. Papers include: (1) "Psychiatry and the TC" (Jerome Jaffe); (2) "The Chemical Brain" (Sidney Cohen); (3) "Where Does the TC Fail?" (Ab Koster); (4) "Psychiatric Severity…

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

24

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

SciTech Connect

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

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

2013-01-01

25

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

26

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

27

Radio-LC-MS for the characterization of 99mTc-labeled bioconjugates.  

PubMed

This report describes the first example of using radio-LC-MS for determining the composition of (99m)Tc radiopharmaceuticals at the tracer level. The in-line radiometric detector is a useful addition to a standard LC-MS and provides direct correlation between the MS data and the radioactive species in a radiopharmaceutical kit. Complexes [(99m)Tc(HYNICtide)(tricine)(L)] (RP444, L = TPPTS; RP445, L = TPPDS; and RP446, L = TPPMS) were prepared using a decayed generator eluant. All the ternary ligand (99m)Tc complexes show the expected monoprotonated molecular ions, (M + 1)(+), and diprotonated molecular ions, (M + 2)(2+). The LC-MS spectral data support the proposed structure and are consistent with those obtained for their corresponding (99)Tc analogues. Ternary ligand complexes [(99m)Tc(HYNICtide)(tricine)(L)] (L = ISONIC-HE and ISONIC-Sorb) are neutral, and the molecular weights are also lower than that of RP444. Using a fresh generator eluant (24 h prior elution), only 1-2 mCi of (99m)Tc [(7 x 10(-)(12))-(1.5 x 10(-)(11)) mol of technetium complex] are required to obtain a reasonably clean mass spectrum. Radio-LC-MS is a quick and accurate analytical tool for characterization of (99m)Tc radiopharmaceuticals at the tracer level. PMID:10639093

Liu, S; Ziegler, M C; Edwards, D S

2000-01-01

28

Cationic complex: 99m Tc-N,N -dimethyldiaminedithiol  

E-print Network

Gelman Com- pany (U.S.A.). 99 Mo/99m Tc-generator was purchased from DuPont Company. The Filter Unit 30]. The proposed chemical structures are described in Fig. 1. In this experiment, DADT compounds, e.g. 2,2,9,9-tet from the Varian Company (U.S.A.). The mass spectra were obtained with a Hewlett Packard Model 5973

Suh, Young-Ger

29

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

30

Technetium Removal Using Tc-Goethite Coprecipitation  

SciTech Connect

This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Low temperature waste forms coupled with technetium removal using an alternative immobilization process such as Fe(II) treated-goethite precipitation” to increase our understanding of 99Tc long-term stability in goethite mineral form and the process that controls the 99Tc(VII) reduction and removal by the final Fe (oxy)hydroxide forms. The overall objectives of this task were to 1) evaluate the transformation process of Fe (oxy)hydroxide solids to the more crystalline goethite (?-FeOOH) mineral for 99Tc removal and 2) determine the mechanism that limits 99Tc(IV) reoxidation in Fe(II)-treated 99Tc-goethite mineral and 3) evaluate whether there is a long-term 99Tcoxidation state change for Tc sequestered in the iron solids.

Um, Wooyong; Wang, Guohui; Jung, Hun Bok; Peterson, Reid A.

2013-11-18

31

Development and commercialization of high Tc SQUID  

NASA Astrophysics Data System (ADS)

A high Tc SQUID has been developed and is going to be commercialized soon. It features low cost operation with liquid nitrogen coolant and easy operation. Therefore the high Tc SQUID becomes more useful for us than a low Tc SQUID operating with liquid helium. The high Tc SQUID was firstly commercialized by Conductus in California. This was a very pioneer work. Four companies in the US, five companies in Europe and Sumitomo Electric in Japan are now selling it commercially. These commercial SQUIDs are small equipments used for application research in laboratories. Applications are medical diagnosis, nondestructive testing, biomagnetic analysis, geological survey and so on. The high Tc SQUID is a frontier of superconductor electronics. Active research in the development of high Tc SQUID is being conducted worldwide and its commercialization is expected soon.

Itozaki, Hideo

2001-09-01

32

Assessment of macrocyclic triamine ligands as synthons for organometallic 99mTc radiopharmaceuticals.  

PubMed

In a search of coordination molecules suitable to the fac-{(99m)Tc(CO)3}(+) core as a synthon for (99m)Tc-radiopharmaceuticals, nonradioactive rhenium complexes of two macrocyclic triamine compounds with different chelate ring structures, 1,4,7-triazacyclononane (9N3) and 1,5,9-triazacyclododecane (12N3), were synthesized and characterized. (99m)Tc-labeled 9N3 and 12N3 compounds were also prepared using [(99m)Tc(OH 2)3(CO)3](+) and were characterized by both in vitro and in vivo studies. 9N3 produced a single rhenium complex, whereas 12N3 generated two major complexes. The crystallographic data and infrared absorption wavenumber assigned to the C-O stretch suggested that the coordination geometry of 9N3 would be more suitable to fac-{Re(CO)3}(+) than that of 12N3. In contrast, both 9N3 and 12N3 provided a single (99m)Tc-labeled compound. However (99m)Tc-labeled 9N3 exhibited higher stability than (99m)Tc-labeled 12N3 in rat plasma and in the presence of histidine at an elevated temperature. In biodistribution studies, both (99m)Tc-labeled compounds did not show any specific accumulation of radioactivity in any organs except for the excretory organs such as the liver and kidney. These findings showed that 9N3 would constitute a macrocyclic chelating molecule of choice to prepare (99m)Tc radiopharmaceuticals using a fac-{(99m)Tc(CO)3}(+) core. PMID:18269240

Suzuki, Keisuke; Shimmura, Naomi; Thipyapong, Khajadpai; Uehara, Tomoya; Akizawa, Hiromichi; Arano, Yasushi

2008-04-01

33

Pressure dependence of Tc in superconducting cuprates  

NASA Astrophysics Data System (ADS)

The pressure dependence of Tc in Tl 0.5Pb 0.5CaSr 2- xLa xCu 2O 7 was measured to 0.4 GPa for x=0 ( Tc=81 K), x=0.2 ( Tc=101 K) and x=0.4 ( Tc=90 K). These compositions span the peak in Tc versus carrier concentration and were chosen to examine the possible role of pressure-induced charge transfer to the superconducting planes. d Tc/d p passes through a minimum at Tc (max) in contrast to the simple charge transfer model for the 1-2-3 and 1-2-4 compositions of the Y/Ba/Cu/O systems for which d Tc/d p should pass through zero at Tc (max). A more complex charge transfer mechanism which allows for redistribution of charge on the CuO 2 plane is discussed in terms of bond valence sums.

Tallon, J. L.; Lusk, J.; Presland, M. R.

1991-03-01

34

Giant Electrocaloric Effect Around Tc  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

35

Tc7, a Tc1-hitch hiking transposon in Caenorhabditis elegans  

Microsoft Academic Search

We have found a novel transposon in the genome of Caenorhabditis elegans. Tc7 is a 921 bp element, made up of two 345 bp inverted repeats separated by a unique, internal sequence. Tc7 does not contain an open reading frame. The outer 38 bp of the inverted repeat show 36 matches with the outer 38 bp of Tc1. This region

René Rezsohazy; Henri G. A. M van Luenen; Richard M. Durbin; Ronald H. A. Plasterk

1997-01-01

36

VizieR Online Data Catalog: Tc IV, Tc V and Tc VI oscillator strengths (Werner+, 2015)  

NASA Astrophysics Data System (ADS)

The discovery of technetium (Tc) in the atmospheres of red giants by Merrill (1952ApJ...116...21M) constituted convincing proof that s-process nucleosynthesis is indeed occurring in evolved stars. In principle, Tc should still be present in the atmospheres of hot post-AGB stars and (pre-) white dwarfs although, due to radioactive decay, it should be present in decreasing quantities along post-AGB evolution. The recent discovery of a large number of trans-iron group elements in hot white dwarfs with atomic numbers in the range A=30-56 (Zn to Ba) raises the prospect that Tc (A=43) may also be detected. However, this is currently not feasible because no atomic data exist for ionization stages beyond TcII. As an initial step, we calculated atomic energy levels and oscillator strengths of Tc IV-VI and used these data to compute non-local thermodynamic equilibrium (NLTE) model atmospheres to estimate at which minimum abundance level Tc could be detected. We show that Tc lines can be found in ultraviolet spectra of hot white dwarfs provided Tc is as abundant as other detected trans-Fe elements. We find that radiative levitation can keep Tc in large, easily detectable quantities in the atmosphere. A direct identification of Tc lines is still not feasible because wavelength positions cannot be computed with necessary precision. Laboratory measurements are necessary to overcome this problem. Our results suggest that such efforts are beneficial to the astrophysical community. (6 data files).

Werner, K.; Rauch, T.; Kucas, S.; Kruk, J. W.

2015-01-01

37

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

38

Power Systems Development Facility Gasification Test Campaing TC18  

SciTech Connect

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

Southern Company Services

2005-08-31

39

Mobile high- Tc DC SQUID magnetometer  

NASA Astrophysics Data System (ADS)

By optimizing the designing, we made a small size and low noise high- Tc DC SQUID readout electronics with the modulation frequency of 80 kHz. The white flux noise was about 30 ? ?0/ Hz when Sumitomo high- Tc DC SQUID sensor was used. We also proved mobile high- Tc DC SQUID magnetometer was feasible. By using a special compensation method, the SQUID magnetometer could keep locking when it swung about 20° in the earth field. Using this system and eddy-current nondestructive evaluation method, we successfully detected the defect in ferromagnetic material.

He, D. F.; Yoshizawa, M.

2003-05-01

40

Investigation into the standardization of 99Tc.  

PubMed

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

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

2010-01-01

41

New Phenomenon Observed in Thermal Release of 99mTc from Molten 100MoO3  

NASA Astrophysics Data System (ADS)

99mTc for medical use can be separated by thermochromatography from molten 99MoO3. The effect of moist oxygen gas on the 99mTc release from molten 99MoO3 was investigated using a 99Mo/99mTc generator. 99Mo was produced from the reaction of 100Mo(n,2n)99Mo. A new phenomenon was observed: the release rate and the separation and the recovery efficiencies of 99mTc were higher in the moist oxygen gas than in the dry oxygen gas. The present result is a significant development towards the stable production of high quality 99mTc from molten MoO3 with high separation efficiency. The result also provides us a new insight into the interaction between the moist oxygen gas and the molten MoO3.

Kawabata, Masako; Nagai, Yasuki; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji; Sato, Nozomi; Ohta, Akio; Shiina, Takayuki; Kawauchi, Yukimasa

2015-02-01

42

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

43

Technetium generator log form.  

PubMed

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

Vernig, P G

2001-08-01

44

A Monoallelic Deletion of the TcCRT Gene Increases the Attenuation of a Cultured Trypanosoma cruzi Strain, Protecting against an In Vivo Virulent Challenge  

PubMed Central

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

2014-01-01

45

Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds  

SciTech Connect

Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

2014-01-01

46

Human T-cell recognition of Listeria monocytogenes: recognition of listeriolysin O by TcR alpha beta + and TcR gamma delta + T cells.  

PubMed Central

The cell-mediated immune response to Listeria monocytogenes has been well characterized in the mouse. Listeriolysin O (LLO) is a major antigen in murine T-cell recognition of L. monocytogenes. In this study, we show that LLO is also recognized by human TcR alpha beta T cells and TcR gamma delta T cells. Human peripheral blood mononuclear cells (PBMC) cultured in vitro with live listeriae and then expanded with interleukin 2 were shown to respond to purified LLO. The generation of LLO-responsive T cells was dependent on the use of live bacteria during the initial in vitro challenge. LLO-induced proliferation of T cells expanded by exposure of PBMC to live listeriae was major histocompatibility complex restricted. PBMC cultured with formalin-fixed listeriae and subsequently expanded by interleukin 2 gave high proliferative responses to fixed bacteria but failed to respond to LLO. PBMC stimulated in vitro with fixed listeriae contained predominantly TcR alpha beta + T cells. In contrast, PBMC obtained from 85% of the donors studied generated high numbers of TcR gamma delta + T cells following in vitro culture with live listeriae. Using a panel of synthetic amphipathic LLO peptides, we found that LLO-specific T cells from different individuals recognized both common and unique peptides. LLO 470-508 was recognized by three of five individuals, while LLO 203-226 and LLO 107-126 were recognized by two of six individuals. A TcR gamma delta + T-cell line was established from PBMC stimulated with live listeriae and was shown to recognize LLO 470-508. Proliferative responses could be induced in this cell line by peptide-pulsed autologous PBMC but not by peptide-pulsed allogeneic PBMC. Our results establish the importance of LLO in human T-cell recognition of listeriae and show that both TcR alpha beta + T cells and TcR gamma delta + T cells recognize this antigen. Finally, since LLO 470-508 has a high degree of homology with other gram-positive bacterial toxins, the recognition of this peptide by TcR gamma delta + T cells suggests that an important role of these T cells in host defense is the recognition of bacterium-derived toxins. PMID:7768611

Guo, Y; Ziegler, H K; Safley, S A; Niesel, D W; Vaidya, S; Klimpel, G R

1995-01-01

47

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

48

Specific activity effect in the metabolism of Tc  

SciTech Connect

A study of transfer to milk of three isotopes of Tc indicated different results for /sup 99m/TcO/sub 4/-, /sup 95m/TcO/sub 4/-, and /sup 99/TcO/sub 4/-. When the three isotopes were given orally to lactating goats in separate experiments, the milk transfer coefficients increased with decreasing specific activity. Gut absorption of Tc administered as pertechnetate (TcO/sub 4/-) was decreased by reduction of TcO/sub 4/- in the rumen. The rate of reduction of TcO/sub 4/- in the rumen was greater for higher specific activity doses of Tc. These results suggest that the specific activity of a radioisotope may significantly influence the estimated dose to humans from contaminated milk and, probably, other food products.

Ennis, M.E. Jr.; Johnson, J.E.; Ward, G.M.; Voigt, G.M.

1988-02-01

49

99mTc: Labeling Chemistry and Labeled Compounds  

NASA Astrophysics Data System (ADS)

This chapter reviews the radiopharmaceutical chemistry of technetium related to the synthesis of perfusion agents and to the labeling of receptor-binding biomolecules. To understand the limitations of technetium chemistry imposed by future application of the complexes in nuclear medicine, an introductory section analyzes the compulsory requirements to be considered when facing the incentive of introducing a novel radiopharmaceutical into the market. Requirements from chemistry, routine application, and market are discussed. In a subsequent section, commercially available 99mTc-based radiopharmaceuticals are treated. It covers the complexes in use for imaging the most important target organs such as heart, brain, or kidney. The commercially available radiopharmaceuticals fulfill the requirements outlined earlier and are discussed with this background. In a following section, the properties and perspectives of the different generations of radiopharmaceuticals are described in a general way, covering characteristics for perfusion agents and for receptor-specific molecules. Technetium chemistry for the synthesis of perfusion agents and the different labeling approaches for target-specific biomolecules are summarized. The review comprises a general introduction to the common approaches currently in use, employing the N x S4-x , [3+1] and 2-hydrazino-nicotinicacid (HYNIC) method as well as more recent strategies such as the carbonyl and the TcN approach. Direct labeling without the need of a bifunctional chelator is briefly reviewed as well. More particularly, recent developments in the labeling of concrete targeting molecules, the second generation of radiopharmaceuticals, is then discussed and prominent examples with antibodies/peptides, neuroreceptor targeting small molecules, myocardial imaging agents, vitamins, thymidine, and complexes relevant to multidrug resistance are given. In addition, a new approach toward peptide drug development is described. The section has a focus on coordination and labeling chemistry, but biological results are briefly summarized as well. The last (and shortest) section finally intends to give a (subjective) outlook for the future role of 99mTc-based radiopharmaceuticals. Critical comments are spread over the whole article but are concentrated in this section. Despite the increasing competition of diagnostic radiopharmacy by other commonly applied methods in medicine such as magnetic resonance imaging (MRI) or ultrasound, the authors are convinced that 99mTc will play a key role also in future if novel approaches are added and the requirements from chemistry biology and the market considered in research to a stronger extent.

Alberto, R.; Abram, U.

50

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. PMID:24593987

2014-01-01

51

Nitriles form mixed-coligand complexes with (99m)Tc-HYNIC-peptide.  

PubMed

Using a 12-amino acid peptide conjugated with HYNIC as a model, we investigated nitriles as possible coligands for labeling with (99m)Tc. After the preparation of the (99m)Tc labeled HYNIC-peptide using tricine as coligand, the addition of acetonitile was found by reverse phase HPLC to block further coligand exchange with ethylenediamine diacetic acid (EDDA) at room temperature. The addition of this nitrile changed the pharmacokinetics of the (99m)Tc labeled peptide in normal mice towards faster clearance and significant differences in accumulation in most tissues sampled. By replacing acetonitrile with cyanoacetate, a nitrile not present in the HPLC eluant, it was possible to show the existence of a new, more hydrophilic, species by reverse phase HPLC. We conclude that nitriles can act as coligands for HYNIC-conjugated peptides labeled with (99m)Tc and tricine. Furthermore, the presence of acetonitrile during Sep-Pak or HPLC purification may inadvertently generate a mixed tricine/acetonitile coligand (99m)Tc-HYNIC-peptide complex. PMID:11786281

Liu, Guozheng; Wescott, Charles; Sato, Aaron; Wang, Yi; Liu, Ning; Zhang, Yu-Min; Rusckowski, Mary; Hnatowich, Donald J

2002-01-01

52

d-wave Paraconductivity Characterization of Tc Variations in High-Tc Superconducting Films  

NASA Astrophysics Data System (ADS)

The fluctuation conductivity above Tc (the paraconductiviy) in films of Bi2Sr2CaCu2O8+d (Bi2212) and YBa2Cu3O7-? (YBCO) with Tc variations is analyzed in terms of theoretical formulae based on the d-wave superconductivity. It is found that experimental data are describable by the Aslamazov-Larkin term provided that a total-energy cutoff effect is taken into account though there are deviations in the fits for the YBCO case, which can be improved by considering overall contributions to the paraconductivity. The dependence of the fluctuation amplitude upon Tc is reconciled with the d-wave theory.

Kasahara, M.; Mori, N.; Ishibashi, T.

53

Telecom 2-B and 2-C (TC2B and TC2C)  

NASA Technical Reports Server (NTRS)

The DSN (Deep Space Network) mission support requirements for Telecom 2-B and 2-C (TC2B and TC2C) are summarized. These Telecom missions will provide high-speed data link applications, telephone, and television service between France and overseas territories as a follow-on to TC2A. Mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

Dulac, J.; Alvarez, H.

1991-01-01

54

Power Systems Development Facility Gasification Test Campaign TC22  

SciTech Connect

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

Southern Company Services

2008-11-01

55

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

56

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

57

Electronic structure of high-Tc superconductors  

Microsoft Academic Search

The band structure of doped high-Tc superconductors (La2-xSrxCuO4, etc.) is calculated. The mobile hole is considered in a ferromagnetic background of localized spins. Strong electron-electron Coulomb interaction as well as strong coupling with the excitons play an important role in the band formation. The charged quasiparticle in the x2-y2 band has spin S=0 with a small admixture of S=1 state.

V. V. Flambaum; O. P. Sushkov

1991-01-01

58

High- Tc superconductivity: phenomenology and microscopics  

NASA Astrophysics Data System (ADS)

The Luttinger-Wart sum rule is used as the start-point of a consistent semi-phenomenological description of the one-electron spectrum in solids. For normal metals it is essentially the Fermi-liquid theory but the effects of the Coulomb correlations are explicitly included. It is shown that the BCS theory can be formulated for strongly correlated metals, although the accuracy of this description decreases along with enhancement of Tc.

Eliashberg, G. M.

1993-11-01

59

Telecom 2-A (TC2A)  

NASA Technical Reports Server (NTRS)

The DSN (Deep Space Network) mission support requirements for Telecom 2-A (TC2A) are summarized. The Telecom 2-A will provide high-speed data link applications, telephone, and television service between France and overseas territories. The mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

Dulac, J.; Latour, J.

1991-01-01

60

Impurity doping effect in high Tc superconductors  

NASA Astrophysics Data System (ADS)

It has been observed that impurity doping and ion-beam-induced damage in high Tc superconductors cause a metal-insulator transition and thereby suppress the critical temperature. Based on our recent theory of the weak localization effect on superconductors,(Yong-Jihn Kim and K. J. Chang, unpublished (1997)) we examine the variation of Tc with increasing of impurity concentration (x) in La_1.85Sr_0.15Cu_1-xA_xO4 systems, where A= Fe, Co, Ni, Zn, or Ga. We find that the doping impurity decreases the scattering matrix elements for electron-electron attractions, such as V_nn'=-V[1-2\\over ? k_Fl ln(L/l)], where L and l are the inelastic and elastic mean free paths, respectively. Using the mean free path l determined from resistivity data, we find good agreements between our calculated values for Tc and experiments except for Ni-doped samples. We suggest that Ni mpurities may enhance the pairing interaction in some way, and discuss the effect of Ni on the dynamic spin susceptibility.

Kim, Yong-Jihn; Chang, K. J.

1998-03-01

61

Mechanisms of conventional and high Tc superconductivity  

SciTech Connect

This book gives a careful and objective review of theories of superconductivity in traditional superconductors, organics, and high Tc cuprates. Of course, the authors do still present their own theories of cuprate superconductivity, but only in the final chapter after other possibilities have been discussed. The book should be especially useful for researchers entering the field of high Tc superconductivity. The reviews of photon mediated pairing and strong coupling theory are very welcome, since much of this material has not been reviewed since the classic 1969 volume edited by Parks. In particular the authors dispel the various myths that phonon mediated pairing leads to upper bounds on Tc. In addition to phonon mediated pairing the book discussed in detail pairing due to exchange of acoustic (demon) plasmons, excitons, or magnetic fluctuations. There have been so many diverse mechanisms based on strong correlation and large U Hubbard models that a book like this can only discuss a limited selection of the main contenders. In particular here the emphasis on Fermi liquid based models no doubt reflects the authors` own point of view. A whole chapter discusses the concepts of induced superconductivity, in the proximity effect, and its application to materials with several different electronic subsystems.

Kresin, V.L.; Morawitz, H.; Wolf, S.A.

1993-12-31

62

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

63

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

64

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

65

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

66

Interdecadal variation of TC frequency in Japan  

NASA Astrophysics Data System (ADS)

This study analyzed the climate regime shift using statistical change-point analysis on the time-series tropical cyclone (TC) frequency that affected Japan in July to September. The result showed that there was a significant change in 1995, and since then, it showed a trend of rapidly decreasing frequency. To determine the reason for this, differences between 1995 to 2012 (9512) period and 1978 to 1994 (7894) period were analyzed. First, regarding TC genesis, TCs during the 9512 period showed a characteristic of genesis from the southeast quadrant of the tropical and subtropical western North Pacific and TCs during the 7894 period showed their genesis from the northwest quadrant. Regarding a TC track, TCs in the 7894 period had a strong trend of moving from the far east sea of the Philippines via the East China Sea to the mid-latitude region in East Asia while TCs in the 9512 period showed a trend of moving from the Philippines toward the southern part of China westward. Thus, TC intensity in the 7894 period, which can absorb sufficient energy from the sea as they moved a long distance over the sea, was stronger than that of 9512. Large-scale environments were analyzed to determine the cause of such difference in TC activity occurred between two periods. During the 9512 period, anomalous cold and dry anticyclones were developed strongly in the East Asia continent. As a result, Korea and Japan were affected by the anomalous northerlies thereby preventing TCs in this period from moving toward the mid-latitude region in East Asia. Instead, anomalous easterlies (anomalous trade wind) were developed in the tropical western Pacific so that a high passage frequency from the Philippines to the south China region along the anomalous steering flows was revealed. The characteristics of the anomalous cold and dry anticyclone developed in the East Asia continent were also confirmed by the analysis of air temperature, relative humidity, and sensible heat net flux showing that most regions in East Asia had negative values.

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

2014-07-01

67

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

68

[c.2381-3T>C mutation of DMD gene: a rare SNP without significant pathogenicity].  

PubMed

OBJECTIVE To clarify the nature of a DMD splice acceptor mutation c.2381-3T>C. METHODS Genomic DNA was extracted from 5 members of a family affected with DMD. For an obligatory carrier, after excluding gross deletion and duplication of the DMD gene with multiplex ligation-dependent probe amplification (MLPA) method, all coding and splice site sequences of the DMD gene were analyzed with Next Generation Sequencing followed by confirmation with targeted Sanger sequencing. Mutations of the carrier were detected in other 4 members. For the splice site mutation, mini-gene was constructed and expressed in vitro to detect the number of transcript and cDNA sequence. RESULTS A known nonsense mutation (c.8038C>T, p.Arg2680Ter) was identified in the carrier, her sister and the mother. The rest 4 members, except for the mother from the first generation, have all carried the c.2381-3T>C mutation. The latter has been described as a splice site mutation to cause DMD. One of 135 male adults without DMD was also detected to have carried the c.2381-3T>C mutation. No additional transcript was produced by the mini-genes containing c.2381-3T>C mutation. CONCLUSION The c.8038C>T?p.Arg2680Ter?mutation of DMD gene probably underlies the disease in this family. The presence of the c.2381-3T>C mutation in a asymptomatic male and a non-DMD male control, together with the normal in vitro expression of the mini-gene carrying the c.2381-3T>C, strongly suggested that the c.2381-3T>C mutation collected in the Human Gene Mutation Database is a rare SNP without significant pathogenicity. PMID:25636106

Yan, Yuanlong; Yang, Yuan

2015-02-10

69

Technetium99m generators based on neutron irradiated 12-molybdocerate as column matrix  

Microsoft Academic Search

Neutron irradiated 12-molybdocerate(IV) is evaluated as a column matrix for use in preparation of small chromatographic column type99mTc generators. Greater than 87% of the generated99mTc activity is immediately and reproducibly eluted with passing 10 cm3 of saline or chromated saline solutions through 3.0 g of molybdocerate column bed at flow rates of about 1.0 cm3\\/min. The elution performance of99mTc does

M. A. El-Absy; I. M. El-Naggar; A. I. Audah

1994-01-01

70

Structural Investigation of Technetium-Diphosphonate Complex 99mTc-MDP  

Microsoft Academic Search

Density functional theory method has been employed to investigate the structures of the prototypical technetium-labeled diphosphonate complex 99mTc-MDP, where MDP represents methylenediphosphonic acid. A total of 14 trial structures were generated by allowing for the geometric, conformational, charge, and spin isomerism. Based on the optimized structures and calculated energies at the B3LYP\\/LANL2DZ level, two stable isomers were determined for the

Ling Qiu; Jian-guo Lin; Xue-hai Ju; Xue-dong Gong; Shi-neng Luo

2011-01-01

71

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

Microsoft Academic Search

The DOE Fuel Cycle Research & Development (FCR&D) Program is developing aqueous and electrochemical approaches to the processing of used nuclear fuel that will generate technetium-bearing waste streams. This final report presents Pacific Northwest National Laboratory (PNNL) research in FY10 to evaluate an iron-based alloy waste form for Tc that provides high waste loading within waste form processing limitations, meets

Edgar C. Buck; Doinita Neiner

2010-01-01

72

Diversification in the Supply Chain of 99Mo Ensures a Future for 99mTc.  

PubMed

The uncertain availability of (99m)Tc has become a concern for nuclear medicine departments across the globe. An issue for the United States is that currently it is dependent on a supply of (99m)Tc (from (99)Mo) that is derived solely by production outside the United States. Since the United States uses half the world's (99)Mo production, the U.S. (99)Mo supply chain would be greatly enhanced if a producer were located within the United States. The fragility of the old (99)Mo supply chain is being addressed as new facilities are constructed and new processes are developed to produce (99)Mo without highly enriched uranium. The conversion to low-enriched uranium is necessary to minimize the potential misuse of highly enriched uranium in the world for nonpeaceful means. New production facilities, new methods for the production of (99)Mo, and a new generator elution system for the supply of (99m)Tc are currently being pursued. The progress made in all these areas will be discussed, as they all highlight the need to embrace diversity to ensure that we have a robust and reliable supply of (99m)Tc in the future. PMID:24854794

Cutler, Cathy S; Schwarz, Sally W

2014-05-22

73

Research and development of high-Tc SMES  

Microsoft Academic Search

High-Tc superconducting technology is thought to provide many merits for SMES systems. For example, a cryocooled system can be used as a cooling system for High-Tc superconducting coils, indicating that an operation temperature can be selected from a wide-temperature range below critical temperatures. Refrigerator cooling operation temperature for High-Tc SMES can be elevated more than 20 K from conventional 4.2

Ataru Ichinose; Hirofumi Kasahara; Hisayoshi Sakaki; Shirabe Akita; Atsushi Ishiyama; Atsushi Maruyama; Seiichi Koso

2005-01-01

74

Transposition of Tc1 in the Nematode Caenorhabditis elegans  

Microsoft Academic Search

We have identified a strain of Caenorhabditis elegans in which the transposable element Tc1 is genetically active. Most spontaneous mutations affecting the unc-54 myosin heavy chain gene of C. elegans variety Bergerac are due to insertions of Tc1 within unc-54. The Bergerac genome contains an unusually high number of Tc1 elements, but this is not responsible for transpositional activity. Another

David Eide; Philip Anderson

1985-01-01

75

Superconducting fluctuations and disorder in high-Tc cuprates  

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

76

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. PMID:24568867

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

2014-01-01

77

Exploring platelet chemokine antimicrobial activity: nuclear magnetic resonance backbone dynamics of NAP-2 and TC-1.  

PubMed

The platelet chemokines neutrophil-activating peptide-2 (NAP-2) and thrombocidin-1 (TC-1) differ by only two amino acids at their carboxy-terminal ends. Nevertheless, they display a significant difference in their direct antimicrobial activities, with the longer NAP-2 being inactive and TC-1 being active. In an attempt to rationalize this difference in activity, we studied the structure and the dynamics of both proteins by nuclear magnetic resonance (NMR) spectroscopy. Using 15N isotope-labeled protein, we confirmed that the two monomeric proteins essentially have the same overall structure in aqueous solution. However, NMR relaxation measurements provided evidence that the negatively charged carboxy-terminal residues of NAP-2 experience a restricted motion, whereas the carboxy-terminal end of TC-1 moves in an unrestricted manner. The same behavior was also seen in molecular dynamic simulations of both proteins. Detailed analysis of the protein motions through model-free analysis, as well as a determination of their overall correlation times, provided evidence for the existence of a monomer-dimer equilibrium in solution, which seemed to be more prevalent for TC-1. This finding was supported by diffusion NMR experiments. Dimerization generates a larger cationic surface area that would increase the antimicrobial activities of these chemokines. Moreover, these data also show that the negatively charged carboxy-terminal end of NAP-2 (which is absent in TC-1) folds back over part of the positively charged helical region of the protein and, in doing so, interferes with the direct antimicrobial activity. PMID:21321145

Nguyen, Leonard T; Kwakman, Paulus H S; Chan, David I; Liu, Zhihong; de Boer, Leonie; Zaat, Sebastian A J; Vogel, Hans J

2011-05-01

78

Imprecise excision of the Caenorhabditis elegans transposon Tc1 creates functional 5' splice sites.  

PubMed

Imprecise excision of the Caenorhabditis elegans transposon Tc1 from a specific site of insertion within the unc-54 myosin heavy chain gene generates either wild-type or partial phenotypic revertants. Wild-type revertants and one class of partial revertants contain insertions of four nucleotides in the unc-54 third exon (Tc1 "footprints"). Such revertants express large amounts of functional unc-54 myosin despite having what would appear to be frameshifting insertions in the unc-54 third exon. We demonstrate that these Tc1 footprints act as efficient 5' splice sites for removal of the unc-54 third intron. Splicing of these new 5' splice sites to the normal third intron splice acceptor removes the Tc1 footprint from the mature mRNA and restores the normal translational reading frame. Partial revertant unc-54(r661), which contains a single nucleotide substitution relative to the wild-type gene, is spliced similarly, except that the use of its new 5' splice site creates a frameshift in the mature mRNA rather than removing one. In all of these revertants, two alternative 5' splice sites are available to remove intron 3. We determined the relative efficiency with which each alternative 5' splice site is used by stabilizing frameshifted mRNAs with smg(-) genetic backgrounds. In all cases, the upstream member of the two alternative sites is used preferentially (> 75% utilization). This may reflect an inherent preference of the splicing machinery for the upstream member of two closely spaced 5' splice sites. Creation of new 5' splice sites may be a general characteristic of Tc1 insertion and excision events. PMID:7513051

Carr, B; Anderson, P

1994-05-01

79

99Tc Process Monitoring System In-Lab Performance Characterization  

SciTech Connect

Executive Summary A 99Tc Process Monitoring (Tc-Mon) System has been designed and built for deployment at the recently constructed 200 West Pump & Treat (200W P&T) Plant in the 200 West Area ZP-1 Operable Unit of the Hanford Site. The plant is operated by CH2M Hill Plateau Remediation Company (CHPRC). The Tc-Mon system was created through collaboration between Pacific Northwest National Laboratory (PNNL) and Burge Environmental, Inc. The new system’s design has been optimized based on experience from an earlier field test (2011) of a prototype system at the 200W-ZP-1 Interim Pump & Treat Plant. A portion of the new 200W P&T Plant is dedicated to removal of 99Tc from contaminated groundwater in the 200 West Area. 99Tc, as the pertechnetate anion (99TcO4-), is remediated through delivery of water into two trains (Trains A and B) of three tandem extraction columns filled with Purolite A530E resin. The resin columns cannot be regenerated; therefore, once they have reached their maximum useful capacity, the columns must be disposed of as radioactive waste. The Tc-Mon system’s primary duty will be to periodically sample and analyze the effluents from each of the two primary extraction columns to determine 99Tc breakthrough. The Tc-Mon system will enable the CH2M Hill Plateau Remediation Company (CHPRC) to measure primary extraction column breakthrough on demand. In this manner, CHPRC will be able to utilize each extraction column to its maximum capacity. This will significantly reduce column disposal and replacement costs over the life of the plant. The Tc-Mon system was constructed by Burge Environmental, Inc. and was delivered to PNNL in June 2013 for setup and initial hardware and software performance testing in the 325 Building. By early July, PNNL had initiated an in-laboratory performance characterization study on the system. The objective was to fully calibrate the system and then evaluate the quality of the analytical outputs 1) against a series of clean groundwater samples prepared as 99Tc standards, and 2) on actual 200W P&T Plant grab samples containing 99Tc (and other radioactive and non-radioactive contaminants) at levels reported by the Waste Sampling and Characterization Facility. These grab samples included pre-treated (Pre-Resin) and post-treated (Post-Resin) 200W P&T Plant waters for May through August 2013. This report contains the following information: • The genesis of the 99Tc sensor and the Tc-Mon analytical system. • A description of the Tc-Mon system’s major hardware and software components. • A description of the operational principles behind the 99Tc sensor. • Results from the calibration of three components within the Tc-Mon system. The three systems requiring calibration are: 1. Sampling Chamber 2. Conductivity Sensor 3. 99Tc Sensor • Presentation of analytical results obtained on the fully calibrated Tc-Mon system. This includes a determination of the precision and accuracy of each system defined above. • Estimation of the 99Tc sensor’s minimum detectable activity and limit of quantification. • A brief discussion of potential chemical and radiological influences on the 99Tc sensor based on known contaminants in 200W P&T Plant water. • Observations regarding 99Tc sensor longevity.

O'Hara, Matthew J.; Niver, Cynthia M.

2014-01-01

80

Expanding the Knowledge of the Geographic Distribution of Trypanosoma cruzi TcII and TcV/TcVI Genotypes in the Brazilian Amazon  

PubMed Central

Trypanosoma cruzi infection is a complex sylvatic enzooty involving a wide range of animal species. Six discrete typing units (DTUs) of T. cruzi, named TcI to TcVI, are currently recognized. One unanswered question concerning the epidemiology of T. cruzi is the distribution pattern of TcII and hybrid DTUs in nature, including their virtual absence in the Brazilian Amazon, the current endemic area of Chagas disease in Brazil. Herein, we characterized biological samples that were collected in previous epizootiological studies carried out in the Amazon Basin in Brazil. We performed T. cruzi genotyping using four polymorphic genes to identify T. cruzi DTUs: mini-exon, 1f8, histone 3 and gp72. This analysis was conducted in the following biological samples: (i) two T. cruzi isolates obtained by culturing of stools from the triatomine species Rhodnius picttipes and (ii) five serum samples from dogs in which trypomastigotes were observed during fresh blood examination. We report for the first time the presence of TcII and hybrid DTUs (TcV/TcVI) in the Amazon region in mixed infections with TcI. Furthermore, sequencing of the constitutive gene, gp72, demonstrated diversity in TcII even within the same forest fragment. These data show that TcII is distributed in the five main Brazilian biomes and is likely more prevalent than currently described. It is very probable that there is no biological or ecological barrier to the transmission and establishment of any DTU in any biome in Brazil. PMID:25551227

Lima, Valdirene dos Santos; Xavier, Samanta Cristina das Chagas; Maldonado, Irene Fabíola Roman; Roque, André Luiz Rodrigues; Vicente, Ana Carolina Paulo; Jansen, Ana Maria

2014-01-01

81

The role of Tc-99m IDA hepatobiliary and Tc-99m colloid hepatic imaging in primary biliary cirrhosis  

SciTech Connect

To assess the presence of primary biliary cirrhosis, 15 patients at various histopathologic stages were studied by Tc-99m IDA hepatobiliary and/or Tc-99m colloid hepatic imaging. In the earlier stages (I and II), seven of eight patients (88%) showed uniform hepatic retention of Tc-99m IDA. Of seven patients in the same stage, however, four (57%) showed no abnormality on Tc-99m colliod imaging. In three of these four negative patients (75%), uniform hepatic retention of Tc-99m IDA was noted. In the later stages (III and IV), all seven patients showed decreased clearance with or without delayed tracer appearance in the intestine and prominent hepatic retention on Tc-99m IDA imaging; with Tc-99m colloid imaging there was enlargement of the spleen and increased activity in the spleen and bone marrow. Thus, Tc-99m IDA imaging is considered to be more useful in revealing this functional disorder at the earlier stage of primary biliary cirrhosis and in evaluating progression from an earlier to a later stage of disease. Tc-99m colloid imaging also effectively evaluated progression.

Aburano, T.; Yokoyama, K.; Shuke, N.; Kinuya, S.; Takayama, T.; Tonami, N.; Hisada, K. (Kanazawa Univ. Hospital (Japan))

1991-01-01

82

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

83

Feasibility studies towards future self-sufficient supply of the (99)Mo-(99m)Tc isotopes with Japanese accelerators.  

PubMed

In order to establish a self-sufficient supply of (99m)Tc, we studied feasibilities to produce its parent nucleus, (99)Mo, using Japanese accelerators. The daughter nucleus, (99m)Tc, is indispensable for medical diagnosis. (99)Mo has so far been imported from abroad, which is separated from fission products generated in nuclear reactors using enriched (235)U fuel. We investigated (99m)Tc production possibilities based on the following three scenarios: (1) (99)Mo production by the (n, 2n) reaction by spallation neutrons at the J-PARC injector, LINAC; (2) (99)Mo production by the (p, pn) reaction at Ep = 50-80 MeV proton at the RCNP cyclotron; (3) (99m)Tc direct production with a 20 MeV proton beam from the PET cyclotron. Among these three scenarios, scenario (1) is for a scheme on a global scale, scenario (2) works in a local area, and both cases take a long time for negotiations. Scenario (3) is attractive because we can use nearly 50 PET cyclotrons in Japan for (99m)Tc production. We here consider both the advantages and disadvantages among the three scenarios by taking account of the Japanese accelerator situation. PMID:25504230

Nakai, Kozi; Takahashi, Naruto; Hatazawa, Jun; Shinohara, Atsushi; Hayashi, Yoshihiko; Ikeda, Hayato; Kanai, Yasukazu; Watabe, Tadashi; Fukuda, Mitsuhiro; Hatanaka, Kichiji

2014-01-01

84

System Concepts for Children via LEGO TC logo.  

ERIC Educational Resources Information Center

Discussion of knowledge constructionism focuses on LEGO TC logo, a program that permits control of LEGO toys by means of a computer. A project for 9- and 10-year-old students that uses LEGO TC logo to develop concepts related to automatic control systems is explained. (three references) (LRW)

Gorbunov, Andrei L.

1994-01-01

85

Description of the TC 125 aboard the Mercury simulator  

NASA Technical Reports Server (NTRS)

Two distinct phases of the TC.125 aboard the Mercury Simulator were described to pilots at a meeting in 1979. A three hour "hand on" phase, during which the pilot learns to use the system, and second; a two hour evaluation phase, during which the pilot analyzes the TC.125 and pratices making typical approaches are presented.

1979-01-01

86

Iron oxide waste form for stabilizing 99Tc  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

87

Compressive-stress-induced Tc increase of the low-Tc Bi1.6Pb0.4Sr2Ca2Cu3Ox phase  

Microsoft Academic Search

The effect of compressive stress on Tc is studied for the low-Tc Bi1.6Pb0.4Sr2Ca2Cu3Ox phase. Although stress decreases the Tc of the high-Tc sample, the small compressive stress increases the Tc of the low-Tc phase. The maximum Toffc is about 113.6 K at 0.01 mA\\/mm2 (current density) and 3.92 N\\/mm2 of the low-Tc phase where Toffc is 96.2 K before loading.

Yoshitake Nishi; Kazuya Oguri; Hideo Ohinata; Kenji Tanioka; Yuichiro Kita; Nobuyuki Ninomiya

1990-01-01

88

High-{Tc} rf SQUID magnetometers  

SciTech Connect

The discovery of high temperature superconductors has revived the interest in rf SQUIDS, which, in the case of conventional superconductors had been surpassed in performance by the dc SQUID. Several advantages are offered by the rf SQUID, like the requirement for only a single weak link and a low 1/f noise. With high bias frequencies (> 100 MHz) it is possible to obtain flux noise values comparable to dc SQUIDS. At present, HTS rf SQUIDs offer a field sensitivity of less than 100 fT/{radical}Hz ({at} 1 Hz). This is already sufficient for a number of serious applications. This paper reviews recent developments towards practical rf SQUIDs made of high-{Tc} superconductors.

Mueck, M. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Schicht- und Ionentechnik

1994-12-31

89

Quantitative index calculated by 99mTc-GSA scintigraphy  

PubMed Central

99mTc-galactosyl human serum albumin (GSA) scintigraphy is useful to evaluate hepatic function and hepatic functional reserve. A reliable SPECT and CT integrated system is now commercially available. Using this system, we can obtain 99mTc-GSA SPECT/CT fused imaging with a small registration error. Therefore, the 99mTc-GSA scintigraphy techniques prove more useful in clinical practice than have been previously reported. In the latest Annals of Surgical Oncology on Oct 2014, the uptake index (UI) values calculated from 99mTc-GSA scintigraphy are reported to be useful for predicting the functional reserve of the future remnant liver. In this paper, we describe the usefulness of 99mTc-GSA scintigraphy as well as some cautions that are necessary as regards using the system.

Shiraishi, Shinya; Tsuda, Noriko; Sakamoto, Fumi; Tomiguchi, Seiji; Yamashita, Yasuyuki

2014-01-01

90

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

SciTech Connect

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

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

2011-07-04

91

IRES-driven expression of the capsid protein of the Venezuelan equine encephalitis virus TC-83 vaccine strain increases its attenuation and safety.  

PubMed

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. PMID:23675542

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

2013-01-01

92

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. PMID:23675542

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

2013-01-01

93

Comparison of a new Tc-99m renal function agent, Tc-99m mercaptoacetyltriglycine, with I-131 OIH  

SciTech Connect

The search for a Tc-99m replacement for I-131 hippurate (OIH) has led to the synthesis of (mercaptoacetyltriglycine) Tc-99m MAG/sub 3/, a N/sub 3/S derivative with a single stereochemical form, amenable to it formulation. Mouse biodistribution studies in control and probenecid treated animals indicated that renal excretion of Tc-99m MAG/sub 3/ was superior to OIH in both groups of animals. Protein binding studies, constant infusion clearance studies and extraction efficiencies were performed in rats to determine the potential of this agent for evaluation of renal function. In rat plasma TC-99m MAG/sub 3/ was 78% protein bound while OIH was 34% bound. The constant infusion clearance values for Tc-99m MAG/sub 3/ and OIH were 2.70 and 2.11 ml/min/ 100 gm body weight respectively. Clearance values were determined in the presence of IV administered competitive inhibitors, probenecid and para-aminohippuric acid (PAH). Extraction efficiency studies were performed in rats by arterio-venous differences for Tc-99m MAG/sub 3/ and OIH. Tc-99m MAG/sub 3/ was found to have an extraction efficiency of 84.8% while 69.4% was found for OIH. In summary, TC-99m MAG/sub 3/ is cleared more rapidly than OIH in normal rodents with high specificity. Its clearance, in the presence of tubular transport inhibitors, was similar to OIH when corrected for GFR.

Eshima, D.; Fritzberg, A.R.; Kasina, S.; Johnson, D.L.; Taylor, A.

1985-05-01

94

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

95

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

96

Tc-99m glucoheptonate in detection of lung tumors  

SciTech Connect

Sixty-three patients aged 21-80 yr were examined. Tc-99m glucoheptonate (Tc-GH) scintigraphy was performed in 32 patients: 26 with primary lung carcinoma; six with metastases in lung, mediastinum, and pleura from carcinomas elsewhere; eight with benign pulmonary diseases; and 23 without known pulmonary disease. Tc-GH accumulated in 23 of 26 primary pulmonary carcinomas as active foci. The specificity of Tc-GH scans for neoplasm detection was higher than that of chest radiographs. The visualization of malignant tumors was much better in the late Tc-GH images (5-6 hr) than in the early (1 hr). Metastases from other carcinomas were positive in four of six patients, but they were considerably better detected in the radiographs, except in one patient with metastatic hepatocellular carcinoma. Neoplasms or their metastases in the hilar and mediastinal regions were better detected in the Tc-GH scans than in the chest radiographs. Only one of eight benign lung processes was visualized (as a weak diffuse accumulation of Tc-GH in hilar scar formation), and 23 patients without pulmonary disease had no pathological foci.

Vorne, M.; Sakki, S.; Jaervi, K.; Vaehaetalo, S.

1982-03-01

97

High -Tc superlight bipolarons in novel superconductors  

NASA Astrophysics Data System (ADS)

Over the last decade, several competing models of high-temperature superconductivity (HTSC) have been proposed, none of which have succeeded to explain high values of the superconducting critical temperature Tc without adjustable parameters. Most of the proposed models are based on the short-range electron-electron correlations or/and on a short-range electron-phonon interaction. However, in the cuprates the screening is poor due to the low carrier density, layered crystal structure, and high ionicity of the lattice. Here we develop further a model of HTSC, which explicitly takes into account the long-range origin of both types of interaction [1]. The long-range electron-phonon (Froehlich) interaction binds carriers into real space pairs-small bipolarons with surprisingly low mass but sufficient binding energy, while the long-range Coulomb repulsion keeps them from forming larger clusters. We analytically solve this multi-polaron "Froelich-Coulomb" model of oxides for a zigzag ladder and a perovskite layer [2]. The model numerically explains high Tc values in the cuprates without any fitting parameters. It describes other key features of the cuprates such as the isotope effect on the effective mass, pseudogap, the normal state diamagnetism, anomalous upper critical field, and spectral functions measured in tunnelling and photoemission. We argue that strong coupling of carriers with high-frequency phonons and low Fermi energies is the cause of high critical temperatures of novel superconductors. [1] A.S. Alexandrov, in Models and Phenomenology for Conventional and High-temperature Superconductivity (Course CXXXVI of the International School of Physics`Enrico Fermi'), eds. G. Iadonisi, J.R. Schrieffer and M.L. Chiofalo, (IOS Press, Amsterdam), p. 309 (1998). [2] A.S. Alexandrov and P.E. Kornilovitch, J. Phys.: Condens. Matter 14 (2002) 5337. * Mailing address: Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom; E-mail: a.s.alexandrov@lboro.ac.uk; Phone: (44) 1509 223303; Fax: (44) 1509 223986.

Alexandrov, Sasha

2003-03-01

98

Structural Investigation of Technetium-Diphosphonate Complex 99mTc-MDP  

NASA Astrophysics Data System (ADS)

Density functional theory method has been employed to investigate the structures of the prototypical technetium-labeled diphosphonate complex 99mTc-MDP, where MDP represents methylenediphosphonic acid. A total of 14 trial structures were generated by allowing for the geometric, conformational, charge, and spin isomerism. Based on the optimized structures and calculated energies at the B3LYP/LANL2DZ level, two stable isomers were determined for the title complex. And they were further studied systematically in comparison with the experimental structure. The basis sets 6-31G*(LANL2DZ for Tc), 6-31G*(cc-pVDZ-pp for Tc), and DGDZVP have also been employed in combination with the B3LYP functional to study the basis set effect on the geometries of isomers. The optimized structures agree well with the available experimental data, and the bond lengths are more sensitive to the basis set than the bond angles. The charge distributions were studied by the Mulliken population analysis and natural bond orbital analysis. The results reflect a significant ligand-to-metal electron donation.

Qiu, Ling; Lin, Jian-guo; Ju, Xue-hai; Gong, Xue-dong; Luo, Shi-neng

2011-06-01

99

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

100

The topological susceptibility of SU(3) gauge theory near Tc  

NASA Astrophysics Data System (ADS)

We compute the topological susceptibility ?t in SU(3) lattice gauge theory using fermionic methods based on the Atiyah-Singer index theorem. Near the phase transition we find a smooth crossover behavior for ?t with values decreasing from (191(5) MeV)4 to (100(5) MeV)4 as we increase the temperature from 0.88Tc to 1.31Tc, showing that topological excitations exist far above Tc. Our study is the first large scale analysis of the topological susceptibility at high temperature based on the index theorem and the results agree well with field theoretical methods.

Gattringer, Christof; Hoffmann, Roland; Schaefer, Stefan

2002-05-01

101

Re-Search for Extinct 99Tc and 98Tc in the Early Solar System  

NASA Astrophysics Data System (ADS)

The recent advances in negative thermal ionization mass spectrometry (N-TIMS) of Re and Os (Creaser et al., 1991) offer a new chance to search for isotopic anomalies of ruthenium (Ru) (and possibly Mo) in meteorites. The Ru isotopes are particularly important since they contain two daughter decay products of technicium, ^98Tc (tau(sub)1/2=4.2x10^6 yr) and ^99Tc (tau(sub)1/2=2.1x10^5 yr). Natural Tc is now extinct on Earth due to their short half-life, but may have been present in the early solar system; Ru isotopes might also bear witness of the various processes of nucleosynthesis and of the imperfect mixing of their products in the pre-solar nebula; Ru isotopic composition in fission is drastically different from natural; ^99Tc is crucial because of its very short half-life and is observed directly for several half-lives in s-process-enriched stars during the thermally pulsing, AGB (asymptotic giant branch) phase of evolution. The probability of detecting ^99Tc in this type of stars is typically 70% (Smith and Lambert, 1988). The chemical similarities between Ru and Os yield correspondingly high ionization efficiency for Ru with N-TIMS. Ru is obtained as a byproduct of Os chemistry, as Ru co-distills with Os. This unique combination conveniently enables a survey for extinct Tc by determining isotopic composition of Ru on a wide range of samples together with extensive studies of Re-Os system in geochemical community in the years to come. These arguments prompted us to carry out a systematic re-search for Ru isotopic anomalies initiated by Herr and coworkers more than 30 years ago (Herr et al., 1958). We have measured Ru isotopic composition in one bulk sample and a magnetic fraction of Maralinga carbonaceous chondrite and one bulk sample of the iron meteorite Gibeon. The bulk sample of Maralinga is found to be isotopically indistinguishable from the terrestrial values within analytical uncertainties. In the magnetic fraction, however, a positive deviation (0.89+- 0.24epsilon) of the ^99Ru/^101Ru ratio from the terrestrial mean is observed, a first indication that ^99Tc was alive in the early solar system. With the production ratio of ^99Tc/^99Ru=0.75 (Kappeler et al., 1989), a 2.9+-0.2 m.y. time interval (delta) between the nucleosynthetic process and formation of Maralinga is calculated, assuming there is no significant Tc/Ru fractionation since their production. This time interval is consistent with delta>=1.8 m.y. set by ^41Ca (tau(sub)1/2=1.03x10^5 yr) result (Hutcheon et al., 1984) and delta<=~3 m.y. inferred from ^26Al (tau(sub)1/2=7.16x10^5 yr) result (Lee et al., 1977), and gives the most stringent control on delta for the related nucleosynthetic process. The ^99Ru/^101Ru ratio in Gibeon is within error of the laboratory standard value. Since the nucleosynthetic origins of ^107Pd and ^99Tc are similar, the absence of ^99Ru anomaly (^99Ru*) and the presence of ^107Ag* in Gibeon (Chen and Wasserburg, 1990) indicate that core-mantle differentiation in the parent body of Gibeon happened between 2 and 10 m.y. after the nucleosynthetic sources produced these two parent nuclides. In this time span ^26Al was still alive and thus supports the model of ^26Al being a heat source for early planetary differentiation. Chen, J. H. and Wasserburg, G. J. , Geochim. Cosmochim. Acta. (1990) 54, 1729-1743. Creaser, R. A., Papanastassiou, D. A. and Wasserburg, G. J. (1991) Geochim. Cosmochim. Acta. 55, 397-401. Herr, W., Merz, E., Eberhardt, P., Geiss, J., Lang, C. and Signer, P. (1958) Geochim. Cosmochim. Acta. 14, 158. Hutcheon, I. D., Armstrong, J. T., and Wasserburg, G. J. (1984) LPSC XV, 387-388 (abstract). Kappeler, F., Beer, H., and Wisshak, K. (1989) Rep. Prog. Phys. 52. 945-1013. Lee, T., Papanastassiou, D. A. and Wasserburg, G. J. (1977) Astrophys. J. (Letters) 211, L107-L110. Smith, V. V. and Lambert, D. L. (1988)t. Astrophys. J., 333, 219- 226.

Yin, Q.; Jagoutz, E.; Wanke, H.

1992-07-01

102

Applicability of plasmid calibrant pTC1507 in quantification of TC1507 maize: an interlaboratory study.  

PubMed

To enforce the labeling regulations of genetically modified organisms (GMOs), the application of DNA plasmids as calibrants is becoming essential for the practical quantification of GMOs. This study reports the construction of plasmid pTC1507 for a quantification assay of genetically modified (GM) maize TC1507 and the collaborative ring trial in international validation of its applicability as a plasmid calibrant. pTC1507 includes one event-specific sequence of TC1507 maize and one unique sequence of maize endogenous gene zSSIIb. A total of eight GMO detection laboratories worldwide were invited to join the validation process, and test results were returned from all eight participants. Statistical analysis of the returned results showed that real-time PCR assays using pTC1507 as calibrant in both GM event-specific and endogenous gene quantifications had high PCR efficiency (ranging from 0.80 to 1.15) and good linearity (ranging from 0.9921 to 0.9998). In a quantification assay of five blind samples, the bias between the test values and true values ranged from 2.6 to 24.9%. All results indicated that the developed pTC1507 plasmid is applicable for the quantitative analysis of TC1507 maize and can be used as a suitable substitute for dried powder certified reference materials (CRMs). PMID:22148678

Meng, Yanan; Liu, Xin; Wang, Shu; Zhang, Dabing; Yang, Litao

2012-01-11

103

99mTc-UBI Biokinetics: A Specific Peptide for Infection Detection  

NASA Astrophysics Data System (ADS)

Recently, antimicrobial peptides have been proposed as new agents to distinguish between bacterial infections and sterile inflammatory processes. Based on these considerations, Ubiquicidin peptide 29-41 (UBI) has been labeled with 99mTc using a new direct method showing a radiochemical purity > 97 %, high stability in human serum, and low protein binding. In addition 99mTc-UBI showed a specific in vitro and in vivo binding to bacteria. However its biokinetic parameters have not been evaluated since it is one of the new generation radiopharmaceuticals based on peptide structures. Therefore the aim of this project was to establish the biokinetic model for 99mTc-UBI. An activity from 74 to 148 MBq was injected to patients with bone infection and 5 whole body scans were taken at 1, 30, 120, 240 min and 24 h after radiopharmaceutical administration, with a dual head scanner. Urine was collected for 24 h. An antropomorphic phantom was previously used to calculate the effect of attenuation and scattered radiation on the gamma camera acquisition images. ROIs of the selected organs in patients (kidney, liver, heart, bone, soft tissue and lesion) were drawn, and attenuation and scatter corrected. The % urine elimination at 24 h and time integrated ROIs (cpm/pixel/ROIs) were used to obtain the residence time (?) in each tissue and to establish the biokinetic model. Pharmacokinetic data show that blood clearance is biexponential with a mean residence time in the central compartment of 0.52 h. The images showed non-accumulation in metabolic organs. More than 75 % of the injected activity was eliminated by renal clearance 4 h after 99mTc-UBI administration. The mean radiation dose calculated according to the MIRD formalism was 0.130 mGy/MBq for kidney and the effective dose was 4.29 × 10-3 mSv/MBq.

Rodríguez-Cortés, J.; Meléndez-Alafort, L.; Herrera-Rodríguez, R.; Ferro-Flores, G.; Mitsoura, E.; Martínez-Duncker, C.

2003-09-01

104

Pairing Fluctuations Above Tc: A Comparative Study  

NASA Astrophysics Data System (ADS)

Although the investigation of superconductivity in High Tc Cuprates has been extensive, its microscopic origin is still under debate. An important experimental fact is the universality of many properties of the cuprates (the low dimensionality, the d-wave symmetry of the superconducting gap and the pseudogap), which must be reproduced by any competitive theory. While there is no consensus about the 'glue' that binds two electrons in a pair, one can gain insight by simply providing it, without questioning its nature. The Attractive Hubbard Model for electrons on a lattice provides the means for such an approach, but even if it simplifies the picture considerably, in the coupling regime of interest one needs to rely on approximate theories. We present a comparative study of different versions of the T-matrix approximation in the atomic limit (strong coupling), where the existence of analytical solutions enables us to test how well the approximations work. We also employ a non-perturbative approach due to Y. M. Vilk and A.-M. S. Tremblay and compare it with the T-matrix and the analytical solutions. We discuss the relevance of such a study for other coupling regimes and more realistic models.

Verga, Simona; Gooding, Robert J.; Marsiglio, Frank

2003-03-01

105

(??m)Tc-bisphosphonate-iron oxide nanoparticle conjugates for dual-modality biomedical imaging.  

PubMed

The combination of radionuclide-based imaging modalities such as single photon emission computed tomography (SPECT) and positron emission tomography (PET) with magnetic resonance imaging (MRI) is likely to become the next generation of clinical scanners. Hence, there is a growing interest in the development of SPECT- and PET-MRI agents. To this end, we report a new class of dual-modality imaging agents based on the conjugation of radiolabeled bisphosphonates (BP) directly to the surface of superparamagnetic iron oxide (SPIO) nanoparticles. We demonstrate the high potential of BP-iron oxide conjugation using (??m)Tc-dipicolylamine(DPA)-alendronate, a BP-SPECT agent, and Endorem/Feridex, a liver MRI contrast agent based on SPIO. The labeling of SPIOs with (??m)Tc-DPA-alendronate can be performed in one step at room temperature if the SPIO is not coated with an organic polymer. Heating is needed if the nanoparticles are coated, as long as the coating is weakly bound as in the case of dextran in Endorem. The size of the radiolabeled Endorem (??m)Tc-DPA-ale-Endorem) was characterized by TEM (5 nm, Fe?O? core) and DLS (106 ± 60 nm, Fe?O? core + dextran). EDX, Dittmer-Lester, and radiolabeling studies demonstrate that the BP is bound to the nanoparticles and that it binds to the Fe?O? cores of Endorem, and not its dextran coating. The bimodal imaging capabilities and excellent stability of these nanoparticles were confirmed using MRI and nanoSPECT-CT imaging, showing that (??m)Tc and Endorem co-localize in the liver and spleen In Vivo, as expected for particles of the composition and size of (??m)Tc-DPA-ale-Endorem. To the best of our knowledge, this is the first example of radiolabeling SPIOs with BP conjugates and the first example of radiolabeling SPIO nanoparticles directly onto the surface of the iron oxide core, and not its coating. This work lays down the basis for a new generation of SPECT/PET-MR imaging agents in which the BP group could be used to attach functionality to provide targeting, stealth/stability, and radionuclides to Fe?O? nanoparticles using very simple methodology readily amenable to GMP. PMID:21338098

Torres Martin de Rosales, Rafael; Tavaré, Richard; Glaria, Arnaud; Varma, Gopal; Protti, Andrea; Blower, Philip J

2011-03-16

106

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

107

A search for technetium (Tc II) in barium stars  

NASA Technical Reports Server (NTRS)

The authors searched without success for the lines of Tc II at 2647.02, 2610.00 and 2543.24 A in IUE spectra of the barium stars HR 5058, Omicron Vir, and Zeta Cap. The lack of Tc II implies that the observed s-process enhancements were produced more than half a million years ago and supports the suggestion that the spectral peculiarities of barium stars are probably related to the binary nature of the stars.

Little-Marenin, Irene R.; Little, Stephen J.

1987-01-01

108

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

109

Feasibility study of compact high-Tc superconducting cables  

Microsoft Academic Search

Since high-Tc superconductors have very small lower-critical fields Hc[sub 1], a high-Tc superconducting cable of practical size for power transmission should be so designed that its self-field exceeds Hc[sub 1]. For this reason, AC loss is greater and its evaluation is of importance. This paper reports on the present experiments which suggest that the Bean model provides a rough evaluation

T. Hara; K. Okaniwa; N. Ichiyanagi; S. Tanaka

1992-01-01

110

Unusual extraosseous tumoral accumulation of 99m Tc-MDP  

Microsoft Academic Search

Three cases (rhabdomyosarcoma, lymphoma, and metastatic malignant melanoma) of unexpected increased uptake of methylenediphosphonate labelled by technetium 99m sodium pertechnetate (99mTc-MDP) are described. The possible mechanisms of the extraosseous tumoral accumulation of 99mTc-MDP in these malignancies are discussed. The usefulness of this method for the diagnosis, localization, and follow-up of some extraosseous tumors is evaluated.

I. Garty; J. Risescu; G. Rosen; I. Bar-Ilan

1985-01-01

111

Novel 99 m Tc radiopharmaceuticals with bifunctional chelating agents  

Microsoft Academic Search

Today the main radionuclide used for preparing radiopharmaceuticals throughout the world is 99m\\u000a Tc, thanks to its optimal nuclear-physical characteristics and ready availability. Several approaches are used for tethering\\u000a this radionuclide to biomolecules (peptides, antibodies, etc.); one of them involves the use of so-called bifunctional chelating\\u000a agents (BCAs). These compounds are capable both of binding 99m\\u000a Tc and of linking

A. Ya. Maruk; A. B. Bruskin; G. E. Kodina

2011-01-01

112

The Rise of Tc: A Promising Paradigm via Interfacial Mechanism  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

113

Pitfalls in Tc99m polyphosphate skeletal imaging.  

PubMed

The quality of Tc-PP scans is best in younger patients. In all age groups quality is adversely affected by free TcO4-. This should be suspected if excessive background is present or marked accumulation is noted in the thyroid gland. Direct physician supervision of all studies is recommended. Symptomatic and roentgenographically positive areas may then be determined for special interpretative attention. Objects which attenuate activity should be removed or noted. Potential sources of superficial contamination (product spill, urine, saliva) must be known and considered when extraneous activity does not correlate with skeletal structures or clinical findings. Normal variations in skeletal uptake of Tc-PP include asymmetries between periarticular areas on the right and left, local increases due to physiologic calvarial thickening and uptake in persistently visualized sternal ossification centers. Apparent variations in the vertebral activity may be due to focal plane effects of rectilinear scanners. Hyperemia can cause diffusely increased Tc-PP localization in an entire extremity. This effect may completely obscure a lesion or obscure the extent of a lesion. Tc-PP excretion through the kidneys occasionally provides useful morphologic or functional information concerning the urinary tract which should be inspected on all scans. Abnormal soft tissue uptake occurs in a variety of conditions including healing wounds and some malignant tumors. A large percentage of patients over 40 years of age demonstrate localization of Tc-PP in the walls of the femoral vessels. PMID:4432955

Thrall, J H; Ghaed, N; Geslien, G E; Pinsky, S M; Johnson, M C

1974-08-01

114

Transposition of Tc1 in the nematode Caenorhabditis elegans.  

PubMed

We have identified a strain of Caenorhabditis elegans in which the transposable element Tc1 is genetically active. Most spontaneous mutations affecting the unc-54 myosin heavy chain gene of C. elegans variety Bergerac are due to insertions of Tc1 within unc-54. The Bergerac genome contains an unusually high number of Tc1 elements, but this is not responsible for transpositional activity. Another variety of C. elegans, strain DH424, contains an equally high number of Tc1 elements, but transpositions are not detected. Tc1 insertion mutations are genetically unstable. They revert to unc-54+ in both germ-line and somatic cells. Germ-line revertants are wild type and contain precise or nearly precise excisions of Tc1. Somatic revertants are genetic mosaics; they contain small patches of revertant muscle tissue in otherwise mutant animals. The pattern of mosaicism often allows us to know when and where during muscle development the excisions occur. Somatic reversion can be over 1000-fold more frequent than germ-line reversion. PMID:2984668

Eide, D; Anderson, P

1985-03-01

115

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

116

Development of Spatial Inhomogeneity of Internal Magnetic Field Above Tc in Bi2Sr2Ca1?xYxCu2O8+? Observed by Longitudinal-Field Muon Spin Relaxation  

NASA Astrophysics Data System (ADS)

Longitudinal-field muon-spin-relaxation measurements have revealed inhomogeneous distribution of the internal magnetic field at temperatures above the bulk superconducting (SC) transition temperature, Tc, in slightly overdoped Bi2Sr2Ca1?xYxCu2O8+?. The distribution width of the internal magnetic field, ?, evolves continuously with decreasing temperature toward Tc. The origin of the increase in ? is discussed in terms of the generation of SC domains in a sample.

Tanabe, Yoichi; Adachi, Tadashi; Suzuki, Kensuke M.; Akoshima, Megumi; Heguri, Satoshi; Kawamata, Takayuki; Ishii, Yasuyuki; Suzuki, Takao; Watanabe, Isao; Koike, Yoji

2014-07-01

117

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

118

Iron phosphate glass for immobilization of 99Tc  

SciTech Connect

Technetium-99 (99Tc) can bring serious environmental threats because of its long half-life (t1/2 = ~2.1 x 105 years), high fission yield (~6%), and high solubility and mobility in the ground water. The high volatility makes it difficult to immobilize 99Tc in continuous melters vitrifying 99Tc-containing nuclear wastes in borosilicate glasses. This work explores a possibility of incorporating a high concentration of 99Tc, surrogated by the non-radioactive Re, in an iron phosphate glass by melting mixtures of iron phosphate glass frits with 1.5-6 mass% KReO4 at ~1000 C. The retention of Re achieved was ~1.1 mass%. The normalized Re release by the 7-day Product Consistency Test was <10*2 g/m2. Surprisingly, the Re escaped from the melt within a short time of heating, especially when the temperature was increased. Therefore, 99Tc volatilization would still be a challenging task for its immobilization in iron phosphate glasses.

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

2013-06-15

119

Detection of 99Tc by accelerator mass spectrometry: preliminary investigations  

SciTech Connect

Accelerator mass spectrometry is an established technique for the detection of long-lived radionuclides at environmental levels. At LLNL, planned facility upgrades and advances in detection techniques are allowing us to explore the applicability of AMS to isotopes not previously pursued. One such isotope is technetium-99. We have performed a number of preliminary tests to examine the technical feasibility of AMS for the detection of {sup 99}Tc. The questions addressed were negative ion production in the cesium sputter source, transport efficiency for the ions through the spectrometer, and detection efficiency for {sup 99}Tc ions after the spectrometer. Based on the positive results of these tests, we have begun to develop a measurement protocol. Technetium is co-precipitated with rhodium, added as a carrier, which provides a sample form appropriate for sputtering and an isotope for AMS normalization. The {sup 99}Tc is determined from the measured {sup 99}Tc/{sup 103}Rh ratio. To reduce interference from the isobar {sup 99}Ru, an oxidation/distillation method was employed to lower ruthenium in the rhodium stock solution. Characteristic projectile L x-rays are used for ion detection to allow further subtraction of {sup 99}Ru. Results for a series of standards demonstrated linearity and reproducibility. A sensitivity of {approx}500 fg {sup 99}Tc was obtained in this preliminary work, and indications are that a sensitivity in the low femtogram range should be achievable.

McAninch, J. E., LLNL

1997-04-01

120

The TC double socket above-knee prosthesis.  

PubMed

The conventional total contact suction AK prosthesis presents several disadvantages, such as difficulty in wearing the socket in a sitting position, difficulty in obtaining a favourable disposition of the stump soft tissues in the socket and difficulty in avoiding stump perspiration problems. In an attempt to solve these disadvantages, a new AK prosthesis with a thermoplastic double socket was developed at the Tokyo Metropolitan Rehabilitation Center for the Physically and Mentally Handicapped. The double socket is composed of an external socket attached to the lower parts and a detachable internal socket, and appears to solve all the disadvantages of the conventional prosthesis. This prosthesis is called the TC prosthesis, and abbreviation for the Tokyo Metropolitan Rehabilitation Center. The first model of this prosthesis, (TC-1) has a metal valve. A new rubber sheet valve was developed to solve several disadvantages of the metal valve in the TC-2 prosthesis. Since November 1978 the TC-1 has been fitted to 295 AK amputees, including 9 bilateral AK amputees, and since March 1980, 145 AK amputees have received the TC-2, including 6 bilateral amputees. Satisfactory results have been obtained with both prostheses. PMID:7329773

Koike, K; Ishikura, Y; Kakurai, S; Imamura, T

1981-12-01

121

Applied High-Tc Superconducting Power Machines  

Microsoft Academic Search

Superconductivity is key technology for 21st century. To suppress emission of green house effect gas, applied superconductivity is important. In this paper, the current status of superconducting power machines such as generator, magnetic bearing and motor are described. Most of all studies are the step of demonstration of idea and possibility. There are large gap between physical idea and actual

Tsutomu Hoshino

122

Tc Reductant Chemistry and Crucible Melting Studies with Simulated Hanford Low-Activity Waste  

SciTech Connect

The FY 2003 risk assessment (RA) of bulk vitrification (BV) waste packages used 0.3 wt% of the technetium (Tc) inventory as a leachable salt and found it sufficient to create a significant peak in the groundwater concentration in a 100-meter down-gradient well. Although this peak met regulatory limits, considering uncertainty in the actual Tc salt fraction, peak concentrations could exceed the maximum concentration limit (MCL) under some scenarios so reducing the leachable salt inventory is desirable. The main objective of this study was to reduce the mobile Tc species available within a BV disposal package by reducing the oxidation state of the Tc in the waste feed and/or during melting because Tc in its reduced form of Tc(IV) has a much lower volatility than Tc(VII). Reduced Tc volatility has a secondary benefit of increasing the Tc retention in glass.

Kim, Dong-Sang; Soderquist, Chuck Z.; Icenhower, Jonathan P.; McGrail, B PETER.; Scheele, Randall D.; McNamara, Bruce K.; Bagaasen, Larry M.; Schweiger, Michael J.; Crum, Jarrod V.; Yeager, John D.; Matyas, Josef; Darnell, Lori P.; Schaef, Herbert T.; Owen, Antionette T.; Kozelisky, Anne E.; Snow, Lanee A.; Steele, Marilyn J.

2005-03-30

123

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

124

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

125

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. PMID:21588082

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

2010-01-01

126

Patients with hemoptysis examined by Tc-99m sulfur colloid and Tc-99m-labeled red blood cells: a preliminary appraisal  

SciTech Connect

A prospective study of 16 patients with hemoptysis was conducted over a 2 1/2-year period. Technetium-99m sulfur colloid (Tc-SC) and technetium-99m-labeled red blood cells (Tc-RBC) were sequentially used to identify the general area of bleeding. Tc-SC accurately located the bleeding area in 3 patients and Tc-RBC identified the bleeding area in 8; there were no false-positive studies. Tc-SC scans were positive at 6-10 minutes and all patients had positive Tc-RBC studies. In general, the scans accurately located the source of bleeding as determined by bronchoscopy and/or surgery. Although a trend suggests that Tc-RBC is a more sensitive method, further comparison is needed for corroboration.

Winzelberg, G.G.; Wholey, M.H.; Jarmolowski, C.A.; Sachs, M.; Weinberg, J.H.

1984-11-01

127

Dissociation of Tc-99m DTPA in a nebulizer.  

PubMed

An unexpected biodistribution of nebulized Tc-99m diethylene triamine pentaacetic acid was detected after the ventilation of a patient referred for diagnosis of pulmonary embolism. Radiochemical purity testing of the stock vial showed more than 95% labelling. Further investigation indicated that the problem was possibly associated with a cleaning agent used for the nebulizer, leading to the dissociation of the Tc-99m diethylene triamine pentaacetic acid. Manufacturer's instructions for cleaning of the nebulizer specify the use of 70% denatured ethanol solution, but a chlorine-based agent had been used inadvertently. PMID:21407141

Hinton, Paul J; Clauss, Ralf P

2011-07-01

128

trans-K3[TcO2(CN)4  

SciTech Connect

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 Tc?O 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 environments; interionic 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.

2010-07-14

129

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

130

Effect of cyclophosphamide on the binding of 99mTcO-4 and 99mTc-MDP to blood cells and plasma proteins.  

PubMed

Since the introduction of technetium-99m (99mTc) and its rapid acceptance as a tool in nuclear medicine, very little information is available about its biological action as 99mTc-radiopharmaceuticals. We have determined if cyclophosphamide, an alkylating agent, used in oncology as a chemotherapeutic drug, modifies the binding of 99mTcO-4 and 99mTc-MDP (99mTc-methylenediphosphonic acid) to blood cells and to plasma proteins. The radiopharmaceuticals were injected intravenously (iv) into SW-55 mice (male and female, weight 25 g) and samples of plasma and blood cells were separated. Cyclophosphamide (50 micrograms) was injected iv 1 h before the radiopharmaceuticals. Samples of plasma and blood cells were also precipitated with 5% trichloroacetic acid and soluble and insoluble fractions were isolated. The following results were obtained: 1) cyclophosphamide did not alter (0.25 to 8 h) percent radioactivity of 99mTcO-4 in plasma or blood cells but increased the binding of 99mTc-MDP to blood cells; 2) cyclophosphamide did not alter (0.25 to 8 h) the binding of 99mTcO-4 in insoluble fraction of plasma and decreased (1 to 4 h) percent radioactivity of 99mTc-MDP in the insoluble fraction of plasma; 3) cyclophosphamide increased (0.25 to 4 h) percent radioactivity of 99mTcO-4 in the insoluble fraction of blood cells but did not alter the binding of 99mTc-MDP. Cyclophosphamide and/or its metabolites modified the effective half-life of these radiopharmaceuticals (to 99mTcO-4 was increased 2.3 to 3.4 h and to 99mTc-MDP was decreased 3.3 to 2.1 h) and possibly increased the permeability of blood cells to 99mTcO-4. PMID:7581022

Santos, J S; de-Paula, E F; Correa, T G; de-Freitas, L C; da-Fonseca, L M; Gutfilen, B; Bernardo-Filho, M

1995-01-01

131

Comparison of 99mTc-Tetrofosmin and 99mTc-Sestamibi Uptake in Glioma Cell Lines: The Role of P-Glycoprotein Expression  

PubMed Central

99mTc-Tetrofosmin (99mTc-TF) and 99mTc-Sestamibi (99mTc-MIBI) are SPECT tracers that have been used for brain tumor imaging. Tumor's multidrug resistance phenotype, namely, P-glycoprotein (p-gp), and the multidrug resistance related proteins (MRPs) expression have been suggested to influence both tracers' uptake. In the present study we set out to compare 99mTc-TF and 99mTc-MIBI uptake in high-grade glioma cell lines and to investigate the influence of gliomas p-gp expression on both tracers' uptake. We used four glioma cell lines (U251MG, A172, U87MG, and T98G). The expression of p-gp protein was evaluated by flow cytometry. Twenty ?Ci (7.4·105?Bq) of 99mTc-TF and 99mTc-MIBI were used. The radioactivity in the cellular lysate was measured with a dose calibrator. P-gp was significantly expressed only in the U251MG cell line (P < 0.001). In all gliomas cell lines (U251MG, U87MG, A172, and T98G) the 99mTc-TF uptake was significantly higher than 99mTc-sestamibi. The U251MG cell line, in which significant p-gp expression was documented, exhibited the strongest uptake difference. 99mTc-TF uptake was higher than 99mTc-MIBI in all studied high-grade glioma cell lines. Thus, 99mTc-TF may be superior to 99mTc-MIBI for glioma imaging in vivo. PMID:25436147

Alexiou, George A.; Xourgia, Xanthi; Vartholomatos, Evrysthenis; Kalef-Ezra, John A.; Fotopoulos, Andreas D.; Kyritsis, Athanasios P.

2014-01-01

132

Comparison of (99m)tc-tetrofosmin and (99m)tc-sestamibi uptake in glioma cell lines: the role of p-glycoprotein expression.  

PubMed

(99m)Tc-Tetrofosmin ((99m)Tc-TF) and (99m)Tc-Sestamibi ((99m)Tc-MIBI) are SPECT tracers that have been used for brain tumor imaging. Tumor's multidrug resistance phenotype, namely, P-glycoprotein (p-gp), and the multidrug resistance related proteins (MRPs) expression have been suggested to influence both tracers' uptake. In the present study we set out to compare (99m)Tc-TF and (99m)Tc-MIBI uptake in high-grade glioma cell lines and to investigate the influence of gliomas p-gp expression on both tracers' uptake. We used four glioma cell lines (U251MG, A172, U87MG, and T98G). The expression of p-gp protein was evaluated by flow cytometry. Twenty ?Ci (7.4·10(5)?Bq) of (99m)Tc-TF and (99m)Tc-MIBI were used. The radioactivity in the cellular lysate was measured with a dose calibrator. P-gp was significantly expressed only in the U251MG cell line (P < 0.001). In all gliomas cell lines (U251MG, U87MG, A172, and T98G) the (99m)Tc-TF uptake was significantly higher than (99m)Tc-sestamibi. The U251MG cell line, in which significant p-gp expression was documented, exhibited the strongest uptake difference. (99m)Tc-TF uptake was higher than (99m)Tc-MIBI in all studied high-grade glioma cell lines. Thus, (99m)Tc-TF may be superior to (99m)Tc-MIBI for glioma imaging in vivo. PMID:25436147

Alexiou, George A; Xourgia, Xanthi; Vartholomatos, Evrysthenis; Tsiouris, Spyridon; Kalef-Ezra, John A; Fotopoulos, Andreas D; Kyritsis, Athanasios P

2014-01-01

133

Structural evolution and properties of subnanometer Tc(n) (n = 2-15) clusters.  

PubMed

All-electron scalar relativistic calculations of the geometric and electronic structures of neutral subnanometer Tc(n) (n = 2-15) clusters have been performed using spin-polarized density functional theory. It is shown that the structural evolution of Tc(n) clusters from n = 3 to n = 8 is similar to Mn clusters, which also belong to the group of VIIB transition metals. The calculated binding energy per atom varies gradually from 0.65 eV for Tc(2) to 2.35 eV for Tc(15). The computed electron affinity and ionization potential follow the classical electrostatic metallic droplet model for clusters larger than Tc(6) and converge asymptotically to the experimental value of the bulk Tc work function. A study of the kinetic stability of Tc clusters in terms of the second difference of binding energies and the energy gap between the frontier orbital states predicts Tc(3)(D(3h)), Tc(4)(T(d)), Tc(6)(O(h)), Tc(12)(I(h)), and Tc(13)(I(h)) to be the most stable clusters. Vibrational spectra of Tc clusters are also provided for further experimental identification. PMID:19865752

Weck, Philippe F; Kim, Eunja; Poineau, Frédéric; Czerwinski, Kenneth R

2009-11-21

134

Application of the vibronic model to high- Tc superconductors  

NASA Astrophysics Data System (ADS)

Tc versus the in-plane hole density p phase diagrams, optical, acoustic absorption and dielectric losses in some high- Tc materials are determined on the base of previously proposed vibronic model. The essence of the model is the existence of the off-centered apex oxygens O(A) as local polarizable states due to pseudo Jahn-Teller effect. Tc- p phase diagrams for La 2- xSr xCuO 4 (214), Bi 2Sr 2CuO 6+ y (2201), YBa 2Cu 3O 6+ x (123), Bi 2Sr 2CaCu 2O 8+? (2212) and Tl 2Ba 2Ca 2Cu 3O 10+ y (2223) are calculated assuming that O(A) serve as gates for leaking charge density from CuO 2 planes to dopant-containing layers. The optical absorption of 214 and 123 is calculated in the framework of the charged-phonon mechanism. The temperature dependence of the acoustic absorption and the dielectric losses of 123 and of 214 up to ?100 K due to pseudo-Jahn-Teller tunneling systems with parameters distributed in a narrow range is calculated. All this encourage the conclusion that the tunneling systems originated from pseudo Jahn-Teller effect exist in high- Tc superconductors.

Mihailov, L.; Georgiev, M.; Manov, A.; Vavrek, A.; Dimitrova, M.; Borissov, M.

1994-12-01

135

Tc TUNING OF TUNGSTEN TRANSITION EDGE SENSORS USING IRON IMPLANTATION  

E-print Network

Tc TUNING OF TUNGSTEN TRANSITION EDGE SENSORS USING IRON IMPLANTATION B.A.Younga*, T. Saabb, B developed a technique for precisely tuning the transition temperature of superconducting tungsten (W) films superconductor, tungsten. Our motivation for this work was a desire to develop a reliable technique for optimally

California at Berkeley, University of

136

RF MEMS FOR WIRELESS APPLICATIONS Clark T.-C. Nguyen  

E-print Network

RF MEMS FOR WIRELESS APPLICATIONS Clark T.-C. Nguyen Center for Wireless Integrated Microsystems channel-selector and one featuring an all-MEMS RF front-end. 1. Introduction Recent demonstrations of micro-scale high-Q passive components that utilize microelectromechanical sys- tems (MEMS) technology

Nguyen, Clark T.-C.

137

something great! http://admissions.tc.umn.edu  

E-print Network

as a Second Language (ESL) classes throughout the year. Students who take English as a Second Language courses and international students. To find out more about the English as a Second Language program, visit: http: 612-625-2008 or 1-800-752-1000 Web site: http://admissions.tc.umn.edu ENGLISH LANGUAGE LEARNERS

Amin, S. Massoud

138

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

139

TcBA-AR VII 2004 A DENDROCHRONOLOGICAL FRAMEWORK  

E-print Network

TcBA-AR VII 2004 A DENDROCHRONOLOGICAL FRAMEWORK FOR THE ASSYRIAN COLONY PERIOD IN ASIA MINOR: Dendrochronology, radiocarbon, Middle Bronze Age, Assyrian Colony Period, wiggle-matching Anahtar sbzcukler: Agas Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology, Cornell University, Ithaca, N

Manning, Sturt

140

Tc and its pressure dependence for technetium-based h.c.p. solid solution alloys  

Microsoft Academic Search

The superconducting transition temperature Tc has been determined for a number of technetium-based h.c.p. solid solution alloys. Additions of V, Nb and Mo raise Tc whereas Co, Ni, Ru, and, in particular, Cr and Fe lower Tc relative to pure technetium. The general trend of Tc with the electron per atom ratio is consistent with that expected for a simple

R. N. Shelton; T. F. Smith; T. F. Koch; W. E. Gardner

1975-01-01

141

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. PMID:22195774

2011-01-01

142

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

PubMed

This paper describes a simple methodology for evaluating the bacterial binding of ciprofloxacin labelled with technetium Tc 99m. Using this methodology, the binding of 99mTc-ciprofloxacin by live Escherichia coli was compared with the binding of 99mTc-ciprofloxacin by killed E. coli and the binding of 99mTc-pertechnetate (99mTcO4-) by live E. coli. The antimicrobial effect of 99mTc-ciprofloxacin on E. coli was evaluated. Four groups were defined: live E. coli with 99mTc-ciprofloxacin, live E. coli with 99mTcO4 , killed E. coli with 99mTc-ciprofloxacin, and killed E. coli with 99mTcO4-. After 0, 2, and 4 h of incubation of 1 x 10(8) colony-forming units of E. coli suspended in 5 mL of sterile distilled water with 1.85 MBq of 99mTc-ciprofloxacin or 99mTcO4, 1 mL from each sample was centrifuged. The radioactivity of the bacterial pellet and that of the supernatant were measured separately, and the percentage of sample radioactivity attributable to bacterial binding was calculated. Of the 99mTc-ciprofloxacin, 3.6% to 5.9% was bound to live or killed E. coli; only 0.1% to 0.2% of the 99mTcO4- was bound to live E. coli (P < 0.0001). No significant difference in 99mTc-ciprofloxacin binding was found between live and killed E. coli (P = 0.887). An antimicrobial effect on E. coli was seen with 99mTc-ciprofloxacin: colony counts were reduced after 4 h. The small amount of 99mTc-ciprofloxacin binding and the lack of difference in binding between live and killed E. coli may limit the utility of this methodology in evaluating the presence of E. coli infection. PMID:16479725

Alexander, Kate; Drost, W Tod; Mattoon, John S; Kowalski, Joseph J; Funk, Julie A; Crabtree, Amanda C

2005-10-01

143

Anomalous Isotope Effect in Low and High Tc Superconductors: the Contribution of the Electron Structure  

Microsoft Academic Search

The discovery of the isotope effect on the critical temperature Tc played an important role in the establishment of the BCS theory. The original BCS model leads to Tc ? M^-alpha, where alpha = 1\\/2. However, some of the low Tc superconductors exhibit an anomalous isotope effect, where alpha is much smaller than 1\\/2. The observed values of alpha for

G. L. Zhao; D. Bagayoko

2001-01-01

144

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

SciTech Connect

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

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

1981-06-01

145

99mTc-HYNIC-derivatized ternary ligand complexes for 99mTc-labeled polypeptides with low in vivo protein binding  

Microsoft Academic Search

6-Hydrazinopyridine-3-carboxylic acid (HYNIC) is a representative agent used to prepare technetium-99m (99mTc)-labeled polypeptides with tricine as a coligand. However, 99mTc-HYNIC-labeled polypeptides show delayed elimination rates of the radioactivity not only from the blood but also from nontarget tissues such as the liver and kidney. In this study, a preformed chelate of tetrafluorophenol (TFP) active ester of [99mTc](HYNIC)(tricine)(benzoylpyridine: BP) ternary complex

Masahiro Ono; Yasushi Arano; Takahiro Mukai; Yasushi Fujioka; Kazuma Ogawa; Tomoya Uehara; Tsuneo Saga; Junji Konishi; Hideo Saji

2001-01-01

146

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

147

Comparison of (99m)Tc-HEPIDA and (99m)Tc-MBrIDA from the standpoint of hepatic clearance determination-- preliminary communication.  

PubMed

BACKGROUND. In order to evaluate the functional capacity of the liver by means of clearance determination, the derivative of iminodiacetic acid ((99m)Tc-HEPIDA) has been used in recent decades. Because of recent problems with manufacturing and delivery of (99m)Tc-HEPIDA, an investigation was undertaken with the aim of testing whether a more widely available (99m)Tc-MBrIDA could be used for clearance determination and whether hepatic clearance measured with the use of this compound provides a similarly useful test of hepatic function. MATERIAL AND METHODS. Comparative investigations were performed in 73 patients of both sexes. The state of the efficiency of liver parenchyma was determined based on seven widely used biochemical tests, i.e. levels of: bilirubin, albumin, and gamma globulin; activity of AST, ALT, GGTP, and prothrombin index. The clearances of both radiopharmaceuticals, (99m)Tc-HEPIDA and (99m)Tc-MBrIDA, were determined by means of multisample technique. The results of determination were correlated among themselves and with the results of biochemical tests. The set of results of all estimations allowed a factorial analysis to be performed to find a common factor and to compute the values of factor loadings in particular tests. RESULTS. Obvious correlation between plasma and hepatic clearances of both radiopharmaceuticals was obtained and between plasma clearance of (99m)Tc-MBrIDA and hepatic clearance of (99m)Tc-HEPIDA. Correlation coefficients of (99m)Tc-MBrIDA clearance and the biochemical test results attained somewhat lower values than for (99m)Tc-HEPIDA clearance. Similarly, values of chi(2) test of independence of (99m)Tc-MBrIDA clearances and test results were also less close than for (99m)Tc-HEPIDA clearances. Factorial analysis showed that common factor loading is greatest for hepatic clearance of (99m)Tc-HEPIDA; the values of two loadings of (99m)Tc-MBrIDA clearances are very close, but somewhat lower than those for (99m)Tc-HEPIDA. CONCLUSIONS. From the performed investigations it is possible to conclude that (99m)Tc-MBrIDA clearances may be used for the evaluation of liver parenchyma performance, even if the results may not be as certain as those obtained using (99m)Tc-HEPIDA. PMID:20235057

Surma, Marian J; Dero?, Zbigniew; Frieske, Izabela; Pietrzak-Stelmasiak, Ewa; Ku?mierek, Jacek

2009-01-01

148

(99m)Tc-HYNIC-derivatized ternary ligand complexes for (99m)Tc-labeled polypeptides with low in vivo protein binding.  

PubMed

6-Hydrazinopyridine-3-carboxylic acid (HYNIC) is a representative agent used to prepare technetium-99m ((99m)Tc)-labeled polypeptides with tricine as a coligand. However, (99m)Tc-HYNIC-labeled polypeptides show delayed elimination rates of the radioactivity not only from the blood but also from nontarget tissues such as the liver and kidney. In this study, a preformed chelate of tetrafluorophenol (TFP) active ester of [(99m)Tc](HYNIC)(tricine)(benzoylpyridine: BP) ternary complex was synthesized to prepare (99m)Tc-labeled polypeptides with higher stability against exchange reactions with proteins in plasma and lysosomes using the Fab fragment of a monoclonal antibody and galactosyl-neoglycoalbumin (NGA) as model polypeptides. When incubated in plasma, [(99m)Tc](HYNIC-Fab)(tricine)(BP) showed significant reduction of the radioactivity in high molecular weight fractions compared with [(99m)Tc](HYNIC-Fab)(tricine)(2.) When injected into mice, [(99m)Tc](HYNIC-NGA)(tricine)(BP) was metabolized to [(99m)Tc](HYNIC-lysine)(tricine)(BP) in the liver with no radioactivity detected in protein-bound fractions in contrast to the observations with [(99m)Tc](HYNIC-NGA)(tricine)(2.) In addition, [(99m)Tc](HYNIC-NGA)(tricine)(BP) showed significantly faster elimination rates of the radioactivity from the liver as compared with [(99m)Tc](HYNIC-NGA)(tricine)(2.) Similar results were observed with (99m)Tc-labeled Fab fragments where [(99m)Tc](HYNIC-Fab)(tricine)(BP) exhibited significantly faster elimination rates of the radioactivity not only from the blood but also from the kidney. These findings indicated that conjugation of [(99m)Tc](HYNIC)(tricine)(BP) ternary ligand complex to polypeptides accelerated elimination rates of the radioactivity from the blood and nontarget tissues due to low binding of the [(99m)Tc](HYNIC)(tricine)(BP) complex with proteins in the blood and in the lysosomes. Such characteristics would render the TFP active ester of [(99m)Tc](HYNIC)(tricine)(BP) complex attractive as a radiolabeling reagent for targeted imaging. PMID:11323230

Ono, M; Arano, Y; Mukai, T; Fujioka, Y; Ogawa, K; Uehara, T; Saga, T; Konishi, J; Saji, H

2001-04-01

149

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

150

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

151

Diophantine Generation,  

E-print Network

Diophantine Generation, Horizontal and Vertical Problems, and the Weak Vertical Method Alexandra Shlapentokh Diophantine Sets, Definitions and Generation Diophantine Sets Diophantine Generation Properties of Diophantine Generation Diophantine Family of Z Diophantine Family of a Polynomial Ring Going Down Horizontal

Shlapentokh, Alexandra

152

Identification of iso-TC-1 as a new T-2 toxin metabolite in cow urine.  

PubMed

The structure of a new metabolite T-2 toxin (iso-TC-1) has been established as 3,15-diacetoxy-4-hydroxy-8(3-methyl-3'-hydroxy-butyryloxy)-12, 13-epoxytrichothec-9-ene. The compound is an isomer of TC-1 (a recently isolated T-2 derivative) in which the hydroxy and acetoxy groups at the C-3 and C-4 positions, respectively, are reversed. Direct probe analysis by electron impact (EI) of the underivatized iso-TC-1, as well as EI, positive chemical ionization (CI) in methane, and positive CI in ammonia of its trimethylsilylether or trifluoroacetate provided evidence to support the structure assignment of the new metabolite. The mass spectra of iso-TC-1 were compared with those of TC-1, T-2 toxin and iso-T-2 toxin (the isomer of T-2 toxin having reversed substituents at C-3 and C-4) with regard to molecular weight and fragments involving the substituents at C-3, C-4, C-8 and C-15. Although the two isomers, TC-1 and iso-TC-1, were not easily resolved by thin layer chromatography (TLC), a very good separation of their trimethylsilyl and trifluoroacetate derivatives was obtained by capillary gas chromatography. Acetylation of TC-1 or iso-TC-1 gave the same product. Iso-TC-1 is one of the main products of T-2 metabolism in the cow (more abundant than TC-1) and is found in the urine. PMID:2936399

Visconti, A; Treeful, L M; Mirocha, C J

1985-12-01

153

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

154

Identification of pseudospin partner bands in {sup 108}Tc  

SciTech Connect

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

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

2008-12-15

155

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

156

Pharmacokinetics of intravenously injected Tc-99m labeled ferrite nanobeads  

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

157

High-Tc SQUID Magnetometers for Industrial Applications  

Microsoft Academic Search

We have developed high-Tc SQUID magnetometers for use in a variety of industrial applications. Relatively inexpensive direct-coupled magnetometers have been developed for low-frequency applications including fetal-magnetocardiography. A manufacturable process has been developed to reproducibly fabricate high-resistance (up to 6 Omega) SNS step-edge junctions with YBa_2Cu_3O_7-x as the superconductor and Ag-Au alloy as the normal metal. Magnetic field sensitivities at 77K

Mark Diiorio; Kai-Yueh Yang; Shozo Yoshizumi; Steven Haupt; Don Haran; Roger Koch; Dan Lathrop; Hoke Trammel

1998-01-01

158

NMR and Susceptibility Studies of MnSi above Tc  

Microsoft Academic Search

The itinerant helimagnet MnSi has been studied using NMR and susceptibility techniques above Tc. The magnitude and temperature dependence of the 55Mn Knight shift K, quadrupole coupling nuQ and the nuclear spin-lattice and spin-spin relaxation times T1 and T2 have been determined along with new high temperature measurements of the uniform susceptibility chi(0). Both K and nuQ are shown to

Hiroshi Yasuoka; V. Jaccarino; R. C. Sherwood; J. H. Wernick

1978-01-01

159

''Hot'' spleen on Tc-99m sulfur colloid images  

SciTech Connect

In routine Tc-99m sulfur colloid (SC) liver-spleen imaging, relatively increased splenic uptake when compared with liver uptake is frequently seen. Commonly this is due to decreased hepatic uptake secondary to liver disease, but often it is because of increased uptake in the hyperfunctioning spleen. Reported is a case of lymphoma of the tonsil, with a ''hot'' spleen which was free of tumor. Possible etiology of the ''hot'' spleen is discussed and the known causes listed according to their prevalence.

Lin, D.S.

1983-06-01

160

Sensitive high-Tc SQUID magnetometers for unshielded operation  

Microsoft Academic Search

We have developed sensitive highly reliable high-Tc SQUID magnetometers a reproducible SNS junction fabrication process. In order to enable unshielded operation in the earth's field, we have incorporated flux dams into direct-coupled SQUID magnetometers. By using up to four pickup coils in parallel, each with its own flux dam, an effective area of 0.57 mm2 has been achieved on 24

M. S. Dilorio; K. Yang; S. Yoshizumi; S. G. Haupt; D. Haran; R. H. Koch; F. P. Milliken; J. R. Rozen; D. K. Lathrop; S. Kumar

1999-01-01

161

The Temperature Dependence of High-TC SQUID Magnetometers  

Microsoft Academic Search

We have investigated the response of the flux-locked output of several high-TC SQUID magnetometers to small changes in temperature and for magnetic fields 0-30 mu T. The temperature response DT ? d phiS \\/dT is observed to be linear in the applied magnetic field Ba and can be as large as 500 m phio \\/K where phiS is the flux

R. H. Koch; F. P. Milliken; S. L. Brown; R. A. Altman; W. J. Gallagher; S. G. Haupt; D. K. Lathrop

1997-01-01

162

Tc-99m HMPAO SPECT in a cerebral gunshot wound.  

PubMed

The authors examined regional cerebral blood flow by using Tc-99m HMPAO SPECT studies in a patient who received a gunshot wound to the brain. Although the presence of the retained bullet's fragments adversely affected the quality of CT images and contraindicated MRI studies, the SPECT examination did not have the same constraints and allowed both therapy assessment and prognostic evaluation. The repair of the cortical defect could also be assessed. PMID:7955750

Valle, G; Bonetti, M G; Ciritella, P; Di Fazio, P; Barbano, F; Perrone, E

1994-08-01

163

QCD over $T_c$: hadrons, partons and continuum  

E-print Network

In this paper we provide a physical picture for the QCD phase transition in terms of qualitative changes in the spectral functions. Our approach takes into account the crossover nature of this transition and counts for the observed strong correlation seen in higher order susceptibilities. We demonstrate that the hadron resonance gas, which alone describes the thermodynamics at temperatures $Tgas. The conventional picture of a quark gluon plasma emerges only at $T\\geq 3T_c$.

T. S. Biro; A. Jakovac

2014-05-21

164

Clinical evaluation of /sup 99m/Tc-DMSA renogram  

SciTech Connect

Two hundred-two /sup 99m/Tc-DMSA renograms for urologic problems were evaluated. Some technical aspects of the examination and the value of the scintigraphic depth estimation are discussed. Pre- and postoperative uptake values in patients with renal surgery and sequential postoperative examinations are considered. The value of DMSA renograms in predicting recovery in obstructive uropathy and in deciding to opt for conservative therapy or nephrectomy is discussed.

Van Poppel, H.; Vereecken, R.; Vekemans, K.; Verduyn, H.; Mortelmans, L.; de Roo, M.

1985-04-01

165

Tc-99m DMSA uptake by metastatic colorectal carcinoma.  

PubMed

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

Rondogianni, Phivi; Koniaris, George

2004-08-01

166

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

167

Superconducting stripline resonators and high-Tc materials  

Microsoft Academic Search

The use of high-transition-temperature (Tc) superconducting resonators to stabilize oscillators operating between 1 and 10 GHz is discussed. Measurements of surface resistance are presented and related to the resonator quality factor (Q). Projections of resonator Q and oscillator phase noise are discussed. Improved materials should offer a greater than 20-dB reduction in noise over competing technology. The implications of flicker

D. E. Oates; A. C. Anderson; B. S. Shih

1989-01-01

168

Trypanosoma cruzi diversity in the Gran Chaco: Mixed infections and differential host distribution of TcV and TcVI.  

PubMed

The transmission cycles of Trypanosoma cruzi in the Gran Chaco are complex networks involving domestic and wild components, whose interrelationships are not well understood. Knowing the circuit of transmission of the different Discrete Typing Units (DTUs) of T. cruzi in the complex environment of the Chaco region is relevant to understanding how the different components (reservoirs, vectors, ecotopes) interact. In the present study we identified the DTUs infecting humans and dogs in two rural areas of the Gran Chaco in Argentina, using molecular methods which avoid parasite culture. Blood samples of humans and dogs were typified by PCR-DNA blotting and hybridization assays with five specific DNA probes (TcI, TcII, TcIII, TcV and TcVI). PCR analyses were performed on seropositive human and dog samples and showed the presence of T. cruzi DNA in 41.7% (98/235) and 53% (35/66) samples, respectively. The identification of infective DTUs was determined in 83.6% (82/98) and 91.4% (32/35) in human and dog samples, respectively. Single infections (36.7% - 36/98) and a previously not detected high proportion of mixed infections (47.9% - 47/98) were found. In a 15.3% (15/98) of samples the infecting DTU was not identified. Among the single infections TcV was the most prevalent DTU (30.6% - 30/98) in human samples; while TcVI (42.8% - 15/35) showed the highest prevalence in dog samples. TcV/TcVI was the most prevalent mixed infection in humans (32.6% - 32/98); and TcI/TcVI (14.3% - 5/35) in dogs. Significant associations between TcV with humans and TcVI with dogs were detected. For the first time, the presence of TcIII was detected in humans from this region. The occurrence of one human infected whit TcIII (a principally wild DTU) could be suggested the emergence of this, in domestic cycles in the Gran Chaco. PMID:25445658

Monje-Rumi, María M; Brandán, Cecilia Pérez; Ragone, Paula G; Tomasini, Nicolás; Lauthier, Juan J; Alberti D'Amato, Anahí M; Cimino, Rubén O; Orellana, Viviana; Basombrío, Miguel A; Diosque, Patricio

2015-01-01

169

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

170

99mTc-Galacto-RGD2: A Novel 99mTc-Labeled Cyclic RGD Peptide Dimer Useful for Tumor Imaging  

PubMed Central

This study sought to evaluate [99mTc(HYNIC-Galacto-RGD2)(tricine)(TPPTS)] (99mTc-Galacto-RGD2: HYNIC = 6-hydrazinonicotinyl; Galacto-RGD2 = Glu[cyclo[Arg-Gly-Asp-D-Phe-Lys(SAA-PEG2-(1,2,3-triazole)-1-yl-4-methylamide)

Ji, Shundong; Czerwinski, Andrzej; Zhou, Yang; Shao, Guoqiang; Valenzuela, Francisco; Sowi?ski, Pawél; Chauhan, Satendra; Pennington, Michael; Liu, Shuang

2013-01-01

171

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

172

Evaluation of 99mTc-Labeled Cyclic RGD Dimers: Impact of Cyclic RGD Peptides and 99mTc Chelates on Biological Properties  

PubMed Central

The main objective of this study is to explore the impact of cyclic RGD peptides and 99mTc chelates on biological properties of 99mTc radiotracers. Cyclic RGD peptide conjugates, HYNIC-K(NIC)-RGD2 (HYNIC = 6-hydrazinonicotinyl; RGD2 = E[c(RGDfK)]2 and NIC = nicotinyl) HYNIC-K(NIC)-3G-RGD2 (3G-RGD2 = Gly-Gly-Gly-E[Gly-Gly-Gly-c(RGDfK)]2), and HYNIC-K(NIC)-3P-RGD2 (3P-RGD2 = PEG4-E[PEG4-c(RGDfK)]2), were prepared. Macrocyclic 99mTc complexes [99mTc(HYNIC-K(NIC)-RGD2)(tricine)] (1), [99mTc(HYNIC-K(NIC)-3G-RGD2)(tricine)] (2) and [99mTc(HYNIC-K(NIC)-3P-RGD2)(tricine)] (3) were evaluated for their biodistribution and tumor-targeting capability in athymic nude mice bearing MDA-MB-435 human breast tumor xenografts. It was found that 1, 2 and 3 could be prepared with high specific activity (~111GBq/3mol). All three 99mTc radiotracers have two major isomers, which show almost identical uptake in tumors and normal organs. Replacing the bulky and highly charged [99mTc(HYNIC)(tricine)(TPPTS)] (TPPTS = trisodium triphenylphosphine-3,3?,3?-trisulfonate) with a smaller [99mTc(HYNIC-K(NIC))(tricine)] resulted in less uptake in the kidneys and lungs for 3. Surprisingly, all three 99mTc radiotracers shared a similar tumor uptake (1: 5.73 ± 0.40 %ID/g; 2: 5.24 ± 1.09 %ID/g; and 3: 4.94 ± 1.71 %ID/g) at 60 min p.i. The metabolic stability of 99mTc radiotracers depends on cyclic RGD peptides (3P-RGD2 > 3G-RGD2 ~ RGD2) and 99mTc chelates ([99mTc(HYNIC)(tricine)(TPPTS)] > [99mTc(HYNIC-K(NIC))(tricine)]). Immunohistochemical studies revealed a linear relationship between the ?v?3 expression levels and tumor uptake or tumor/muscle ratios of 3, suggesting that 3 is useful for monitoring the tumor ?v?3 expression. Complex 3 is a very attractive radiotracer for detection of integrin ?v?3 –positive tumors. PMID:22369387

Zhou, Yang; Kim, Young-Seung; Lu, Xin; Liu, Shuang

2012-01-01

173

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

PubMed Central

This report describes a novel ternary ligand system composed of a phenylhydrazine, a crown ether-containing dithiocarbamate (DTC) and a PNP-type bisphosphine (PNP). The combination of three different ligands with 99mTc results in cationic 99mTc-diazenido complexes,[99mTc(NNAr)(DTC)(PNP)]+, with potential radiopharmaceuticals for heart imaging. Synthesis of cationic 99mTc-diazenido complexes can be accomplished in two steps with high yield. For example, the reaction of phenylhydrazine with 99mTcO4? at 100 °C in the presence of excess stannous chloride and 1,2-diaminopropane-N,N,N’,N’-tetraacetic acid (PDTA) results in the [99mTc(NNPh)(PDTA)n] intermediate, which then reacts with sodium N-(dithiocarbamato)-2-aminimethyl-15-Crown-5 (L4) and N,N-bis[2-(bis(3-ethoxypropyl)phosphino)ethyl]ethoxy-ethylamine (PNP6) at 100 °C for 15 min to give the complex, [99mTc(NNPh)(L4)(PNP6)]+ in high yield (> 90%). Cationic complexes [99mTc(NNPh)(DTC)(PNP)]+ are stable for ?6 h. Their composition was determined to be 1:1:1:1 for Tc:NNPh:DTC:PNP using the mixed-ligand experiments on the tracer (99mTc) level, and was further confirmed by the ESI-MS spectral data of a model compound [Re(NNPh)(L4)(L6)]+. It was found that both DTCs and bisphosphines have a significant impact on the lipophilicity of their cationic 99mTc-diazenido complexes. Results from a 99mTc-labeling efficiency experiment showed that 4-hydrazinobenzoic acid (HYBA) might be useful as a bifunctional coupling agent for 99mTc-labeling of small biomolecules. However, the 99mTc-labeling efficiency of HYBA is much lower than that of 6-hydrazinonicotinic acid (HYNIC) with tricine and trisodium triphenylphosphine-3,3’,3”-trisulfonate (TPPTS) as coligands. PMID:16536480

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

2008-01-01

174

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. PMID:24937306

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

2014-01-01

175

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

176

In vitro effect of cyclophosphamide on the binding of radiopharmaceuticals (99mTcO4- and 99mTc-MDP) to blood elements.  

PubMed

Sodium pertechnetate (99mTcO4-) and many 99mTc-products are the radiopharmaceuticals most frequently used in nuclear medicine. Using an in vitro model, we evaluated the effect of cyclophosphamide on percent radioactivity of 99mTcO4- and methylenediphosphonic acid (99mTc-MDP) bound to isolated blood elements. Blood samples were incubated with the two radiopharmaceuticals, plasma and blood cells were separated and precipitated, and soluble and insoluble fractions were separated. To evaluate the effect of cyclophosphamide, blood was incubated with this drug 1 h prior to the addition of the radiopharmaceuticals. The fraction of 99mTcO4- radioactivity was slightly higher in plasma (61.2 to 53.8%) than in blood cells (38.8 to 46.2%) up to 6 h and cyclophosphamide did not interfere with this distribution. The amount of 99mTc-MDP radioactivity was higher in plasma (91.1 to 87.2%) than in blood cells (8.9 to 12.8%) up to 24 h and cyclophosphamide did not modify it. The binding of 99mTcO4- to the insoluble fraction of plasma (4.9 to 6.1%) was low and cyclophosphamide did not interfere with it up to 6 h, but a small blockade (9.8 to 4.8%) was observed at 24 h. From 3 h on, cyclophosphamide slightly inhibited 99mTcO4- binding to blood cells (23.1 to 16.6%) and increased it at 24 h (31.2 to 14.3%). Cyclophosphamide did not alter 99mTc-MDP binding to the insoluble fraction of blood cells and slightly decreased 99mTc-MDP binding to the insoluble fraction of plasma (29.8 to 23.6%) up to 6 h.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7581051

Ripoll-Hamer, E; Freitas, L C; De-Paula, E F; Fonseca, L M; Gutfilen, B; Bernardo-Filho, M

1995-02-01

177

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. PMID:20161398

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

2009-01-01

178

[The utility of quantitative 99mTc-GSA liver scintigraphy in the evaluation of hepatic functional reserve: comparison with 99mTc-PMT and 99mTc-Sn colloid].  

PubMed

Using data from 17 patients with liver cirrhosis and 3 patients with fatty liver, we have compared the utility of 3 hepatic imaging agents in the evaluation of hepatic functional reserve. Evaluated here were 99mTc-galactosyl human serum albumin (GSA) which is a new ligand for hepatic binding protein, 99mTc-N-pyridoxyl-5-methyl tryptophan (PMT) of a hepatobiliary agent, and 99mTc-Sn colloid. In each patient, we performed these 3 imaging studies within a week and also examined hepatic function tests (indocyanine green test, hepaplastin test, choline-esterase, etc). In each imaging study, serial images and dynamic data were obtained after the injection of 99mTc-GSA (185 MBq/3 mg), 99mTc-PMT (185 MBq), or 99mTc-Sn colloid (185 MBq). Using the obtained dynamic data, we analyzed the liver kinetics of the 3 agents based on 1 compartment model with 3 parameters (hepatic clearance, hepatic excretion rate, non-specific volume of distribution). From fitting the liver and heart data to this model, three unknown parameters were determined. Patlak plot was also applied in order to estimate liver uptake rate. Both curve fitting and Patlak plot could determine appropriate parameters in every study. In 99mTc-GSA, a nonlinear 3 compartment model was also applied in order to estimate hepatic blood flow, liver receptor density, and affinity of receptor-GSA binding separately. Using the obtained parameters, we analyzed the correlations between the parameters and the results of hepatic function tests. In all of the parameters, those obtained from 99mTc-GSA imaging showed the most significant statistical correlation with the results of hepatic function tests. From the present results, 99mTc-GSA imaging was concluded to be the best for evaluation of hepatic functional reserve. PMID:1434071

Shuke, N; Aburano, T; Nakajima, K; Yokoyama, K; Sun, B F; Matsuda, H; Muramori, A; Michigishi, T; Tonami, N; Hisada, K

1992-05-01

179

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

SciTech Connect

Technetium speciation, solubility and sorption behavior is strongly dependent on its valence state. Under oxic conditions, Tc exists as the soluble, weakly-sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2·xH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides [diaspore (?-AlOOH) and corundum (?-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (Mössbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11d (diaspore suspension) and 4d (corundum suspension). Mössbauer measurements revealed that the Fe(II) signal became less intense with Tc(VII) reduction, and was accompanied by increase in Fe(III) doublet and magnetically-ordered Fe(III) sextet signals, with latter parameters close to those for hematite. Formation of magnetically ordered Fe(III) did not depend on the oxidant nature, as both Tc(VII) or O2 lead to the formation of a virtually identical hematite-like phase. The Fe(II) doublet displayed no differences in Mössbauer parameters before and after Tc(VII) reduction, likely due to Fe(II) adsorption to similar sites and no Fe(II) sorption to or precipitation within solid phases formed. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2?xH2O. The formation of precursor polymeric TcnOy (4n-2y)+ chains prior to TcO2?xH2O precipitation might explain the formation of the separate TcO2-like phase on corundum without coprecipitated Fe.

Peretyazhko, Tetyana; Zachara, John M.; Heald, Steve M.; Kukkadapu, Ravi K.; Liu, Chongxuan; Plymale, Andrew E.; Resch, Charles T.

2008-08-01

180

Almahata Sitta and the Rubble Pile Asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

On October 6, 2008, asteroid 2008 TC3 was observed to approach Earth and impact the Nubian Desert of northern Sudan 20 hours later. Meteorites were recovered in the following months, with expeditions held in December 2008 and February/March of 2009 (1). Here, we report on the collection of additional meteorites from the Almahata Sitta strewn field in December of 2009, following the 2008 TC3 Workshop held at the University of Khartoum December 5-6. The total recovered mass in the University of Khartoum collection now is 10.5 kg, comprised of 600 individual meteorites. Based on the density of fallen meteorites, the total fallen mass is estimated as 39 +/- 6 kg, of which only about 27 percent has been recovered so far (2). The majority of meteorites are ureilites, some of an anomalous (porous, high in carbon) polymict variety. For the first time, however, macroscopic fragments of other meteorites were recovered as well from the same fall. 20-30 percent in mass of fresh-looking Almahata Sitta meteorites consist of other meteorite types, including H5, EL6, and EH6 meteorites. Those other meteorite types shattered in a similar manner from a 37-km altitude explosion as the predominant ureilites. This makes the 3 to 4 meter sized asteroid a small rubble pile, with accumulated material from different parent bodies. We will review the current status of analysis of the meteorites by members of the Almahata Sitta consortium, the derived physical properties of the meteorites, and the implications for the physical properties of asteroid 2008 TC3, the ureilite parent body, and the possible source region of ureilites in the asteroid belt. References: 1. Jenniskens, P., et al. 2009. Nature. 458, 485-488. 2. Shaddad, M. H., et al. 2010. MAPS in press.

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

2010-10-01

181

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

182

Transverse thermoelectric conductivity and magnetization in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

We use the time-dependent Ginzburg-Landau (TDGL) equation with thermal noise to calculate the transverse thermoelectric conductivity ?xy describing the Nernst effect and magnetization Mz in type-II superconductor in the vortex-liquid regime. The nonlinear interaction term in dynamics is treated within self-consistent Gaussian approximation. The expressions of the transverse thermoelectric conductivity and magnetization including all the Landau levels are presented in explicit form which are applicable essentially to the whole phase. Our results are compared to recent simulation data on high-Tc superconductor.

Tinh, Bui Duc; Quang Hoc, Nguyen; Thu, Le Minh

2014-12-01

183

Primary activity standardization of ??Tc by three different absolute methods.  

PubMed

The activity concentration of a solution of (99)Tc was absolutely determined by liquid scintillation measurements based on the triple-to double-coincidence ratio method (TDCR) and compared with the results given by 4??(LS)-?(NaI) live-timed anticoincidence (with extending dead-time) and classical 4??(PC)-?(NaI) coincidence counting systems based on using (60)Co as the efficiency-tracing radionuclide. The results of anticoincidence and coincidence counting are, respectively, 0.18% and 0.66% higher than the result from TDCR measurements, but they are consistent within uncertainties. PMID:24365467

da Cruz, Paulo A L; da Silva, Carlos J; Moreira, Denise S; Iwahara, Akira; Tauhata, Luiz; Lopes, Ricardo T

2014-05-01

184

Scanning high-Tc SQUID imaging system for magnetocardiography  

NASA Astrophysics Data System (ADS)

A scanning magnetocardiography (MCG) system constructed from SQUID sensors offers potential to basic or clinical research in biomagnetism. In this work, we study a first order scanning electronic high-Tc (HTS) SQUID MCG system for biomagnetic signals. The scanning MCG system was equipped with an x-y translation bed powered by step motors. Using noise cancellation and ?-metal shielding, we reduced the noise level substantially. The established scanning HTS MCG system was used to study the magnetophysiology of hypercholesterolaemic (HC) rabbits. The MCG data of HC rabbits were analysed. The MCG contour map of HC rabbits provides experimental models for the interpretation of human cardiac patterns.

Yang, Hong-Chang; Wu, Tsung-Yeh; Horng, Herng-Er; Wu, Chau-Chung; Yang, S. Y.; Liao, Shu-Hsien; Wu, Chiu-Hsien; Jeng, J. T.; Chen, J. C.; Chen, Kuen-Lin; Chen, M. J.

2006-05-01

185

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

186

1. Generation 1 1. Generation  

E-print Network

1. Generation 1 _________________________________________________________________________ 1. Generation Sound and vibrations or, in more general terms, oscillations of matter (solids or fluids) are generated in many different dynamic processes. The basic mechanisms which underlie these oscillations

Berlin,Technische Universität

187

Synthesis, Radiolabeling and Biological Evaluation of 99mTc-labeled Deoxyglucose Derivatives for Molecular Imaging  

PubMed Central

Two deoxyglucose (DG) derivatives, (?,?)-2-deoxy-2-amino(ethylcarbamate)-D-glucose (ECB-DG) and (?,?)-2-deoxy-2-amino(1,2-dihydroxypropyl)-D-glucose (DHP-DG), were synthesized and radiolabeled successfully with [99mTc(H2O)3(CO)3]+ complex. [99mTc]-ECB-DG and [99mTc]-DHP-DG complexes were prepared (96% and 93% radiochemical purities respectively) by using 46 mCi of Na99mTcO4 in 1 mL saline. Radio-HPLC analysis of [99mTc]- ECB-DG at pH = 7.4, revealed that labeling with 99mTc leads to formation of one radiochemical species with tR = 381 second. Three radiochemical species, Na99mTcO4, [99mTc]-DHP-DG and [99mTc(H2O)3(CO)3]+ complexes with tR = 342 sec, tR = 567 sec and tR = 1586 sec respectively, were obtained when [99mTc]-DHP-DG complex evaluated by HPLC. Biodistribution of two complexes were studied on normal mice at 10, 30 and 60 min post-injections. Compared to the 18F-FDG, [99mTc]-ECB-DG displayed a 2.8-fold reduction in brain uptake (1.7 ± 0.2 versus 0.61% ± 0.09) ,whereas [99mTc]-DHP-DG just showed 1.9-fold reduction in heart uptake (2.2 ± 0.05 towards 1.16±0.10) at 1 h post-injection. On the basis of our results, it seems that ECB-DG and DHP-DG analogues could be used as brain and heart imaging agent respectively. PMID:24250633

Sadeghzadeh, Masoud; Charkhlooiea, Ghorbanali; Johari Daha, Fariba

2013-01-01

188

Temperature dependence of the internal bias in TGS-Alanine crystals near Tc  

Microsoft Academic Search

The temperature, driving field amplitude and frequency dependence of hysteresis loops of triglycine sulfate doped with L-alanine has been examined in the neighborhood of the Curie temperature, Tc. The magnitude of the internal bias associated with L-alanine content shows a remarkable temperature dependence near Tc, decreasing by more than two orders of magnitude within ±1°C of Tc. A semiquantitative interpretation

J. L. Martinez; A. Cintas; E. Dieguez; J. A. Gonzalo

1982-01-01

189

Plasma protein binding of 99mTc-labeled hydrazino nicotinamide derivatized polypeptides and peptides  

Microsoft Academic Search

6-Hydrazinopyridine-3-carboxylic acid (HYNIC) constitutes one of the most attractive reagents to prepare 99mTc-labeled polypeptides and peptides of various molecular weights in combination with two tricine molecules as coligands. Indeed, 99mTc-HYNIC-conjugated IgG showed biodistribution of radioactivity similar to that of 111In-DTPA-conjugated IgG. However, recent studies indicated significant plasma protein binding when the 99mTc labeling procedure was expanded to low molecular weight

Masahiro Ono; Yasushi Arano; Takahiro Mukai; Tomoya Uehara; Yasushi Fujioka; Kazuma Ogawa; Shinji Namba; Morio Nakayama; Tsuneo Saga; Junji Konishi; Kazuko Horiuchi; Akira Yokoyama; Hideo Saji

2001-01-01

190

6-Hydrazinonicotinamide Derivatives as Bifunctional Coupling Agents for 99m Tc-Labeling of Small Biomolecules  

Microsoft Academic Search

99mTc-labeled small biomolecules are a class of receptor-based, target specific radiopharmaceuticals for the detection of various diseases, such as cancer, thrombosis, infection and inflammation. To label a small biomolecule with 99mTc, a bifunctional coupling agent (BFC) is needed so that the 99mTc can be tightly attached to the biomolecule and can localize at the site of the diseased tissue. For

Shuang Liu

191

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

PubMed Central

The nitro group of 2-nitroimidazole (NIM) enters the tumor cells and is bioreductively activated and fixed in the hypoxia cells. 1,4,8,11-tetraazacyclotetradecane (N4) has shown to be a stable chelator for 99mTc. The present study was aimed to develop 99mTc-cyclam-2-nitroimidazole (99mTc-N4-NIM) for tumor hypoxia imaging. N4-NIM precursor was synthesized by reacting N4-oxalate and 1,3-dibromopropane-NIM, yielded 14% (total synthesis). Cell uptake of 99mTc-N4-NIM and 99mTc-N4 was obtained in 13762 rat mammary tumor cells and mesothelioma cells in 6-well plates. Tissue distribution of 99mTc-N4-NIM was evaluated in breast-tumor-bearing rats at 0.5–4?hrs. Tumor oxygen tension was measured using an oxygen probe. Planar imaging was performed in the tumor-bearing rat and rabbit models. Radiochemical purity of 99mTc-N4-NIM was >96% by HPLC. Cell uptake of 99mTc-N4-NIM was higher than 99mTc-N4 in both cell lines. Biodistribution of 99mTc-N4-NIM showed increased tumor-to-blood and tumor-to-muscle count density ratios as a function of time. Oxygen tension in tumor tissue was 6–10?mmHg compared to 40–50?mmHg in normal muscle tissue. Planar imaging studies confirmed that the tumors could be visualized clearly with 99mTc-N4-NIM in animal models. Efficient synthesis of N4-NIM was achieved. 99mTc-N4-NIM is a novel hypoxic probe and may be useful in evaluating cancer therapy. PMID:22719210

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

2012-01-01

192

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

SciTech Connect

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

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

1985-07-03

193

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

SciTech Connect

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

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

1989-08-01

194

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

PubMed

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. PMID:8524324

Rushforth, A M; Anderson, P

1996-01-01

195

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

Microsoft Academic Search

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

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

2000-01-01

196

Leber's Hereditary Optic Neuropathy is Associated with Compound Primary Mutations of Mitochondrial ND1 m.3635G?>?A and ND6 m.14502 T?>?C.  

PubMed

Abstract Purpose: To describe the clinical and molecular characteristics of a Chinese Leber hereditary optic neuropathy (LHON) pedigree with compound mitochondrial DNA (mtDNA) mutations of m.3635G?>?A and m.14502T?>?C. Methods: A total of 22 individuals (2 affected, 20 unaffected) from a five-generation Chinese family with LHON underwent comprehensive ophthalmic examination, including visual acuity, slit lamp examination, fundoscopy, visual field examination and visual evoked potentials (VEP). The complete mtDNA genome of the two patients were amplified by polymerase chain reaction, sequenced using a Bigdye terminator v3.1 cycle sequencing kit and analyzed on an ABI 3700XL Genetic Analyzer. Results: Two LHON patients in the family presented typical features of LHON: painless and progressive deterioration of bilateral vision, bilateral optic atrophy, centrocecal scotomata in both eyes and significant prolonged P100 latency and low amplitude potential in VEP. Compound primary mtDNA mutations of m.3635G?>?A and m.14502T?>?C were identified in these two patients and another 12 living matrilineal members of the pedigree. Haplogroup analysis showed the patients in this LHON family belonged to the N9b1 haplogroup. Modeled mutant structure showed the mutations altered the molecular local space conformation on the surface of ND1 and ND6. Conclusions: Compound mtDNA mutations of m.3635G?>?A and m.14502T?>?C presented with low penetration, and the patients with these compound mutations exhibited mild visual impairment. The biological information analysis suggested that m.14502T?>?C might play a protective role in LHON associated with m.3635G?>?A. The haplogroup analysis indicated that the mtDNA haplogroup might be an important factor affecting the expression of LHON associated with m.3635G?>?A and/or m.14502T?>?C. PMID:24417559

Jin, Xin; Wang, Lifeng; Gong, Yan; Chen, Bing; Wang, Yanhua; Chen, Tingjun; Wei, Shihui

2014-01-13

197

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

198

[Study of biliary tract atresia with HIDA Tc 99].  

PubMed

This report has been motivated to assess the permeability of portoenterostomy with isotopic methods (HIDA Tc 99) in two cases of biliary tract atresia. Both cases have followed a good evolution during 1 1/2 and 8 years respectively, with vanishing of the icterus and achieving an acceptable biliary flow. We used the hepatic gammagraphy with HIDA Tc 99 to evaluate biliary drainage and functional status of biliary tract. Also we used other classical biochemical parameters. This isotope is useful to evaluate the effectiveness of portoenterostomy by the amount and quality of biliary flow, and specially drainage ducts. Actually this method is the safest as compared to all the others, specially transparietohepatic cholangiography. The special characteristics os this isotope and the quality of the records allow the study of both function and structure of hepatic parenchyma through the curves activity/time. This curve measures between the periphery of hepatogram and porta hepatis follows a parallel course to bilirubin clearance. By all that we think that this method, with serial determinations, can be a precise parameter of surgical intervention, and it is useful as a early indicator of bad course, allowing an evaluation of cholangitis and the indication to reintervention. PMID:6881750

Morales, L; Rovira, J; Sancho, N A; Uroz, J A; Juliá, V

1983-04-01

199

Moderately shielded high-Tc SQUID system for rat MCG  

NASA Astrophysics Data System (ADS)

Recently, we have developed a 5-channel high-Tc SQUID system with one signal channel intended for rat magnetocardiography (MCG) in moderately shielded or "quiet" real environment. This system is an adapted version of a human MCG system which has been improved with respect to user-friendliness and stability. A dewar with a cold-warm distance of 7 mm and a refill cycle time of up to one week is utilized. The implemented high-Tc SQUIDs are single-layer devices with grain boundary junctions fabricated at KRISS with laser ablation on 10 mm × 10 mm STO substrates. In order to cancel environmental magnetic noise, three of the five SQUIDs are arranged to build an axial software first-order or second-order gradiometer with a base line of 35 mm. The other two SQUIDs are used for balancing. To overcome previous system instabilities, we have implemented an Earth field compensation for each SQUID. For this, the SQUIDs were mounted in capsules containing integrated field compensation coils. The three Earth field components are measured with an additional triaxial fluxgate, and compensated at the SQUID locations using the low-noise current source of the SQUID readout electronics. This way, the SQUIDs can be cooled and operated in a low residual field that improves system stability and reduces low-frequency SQUID noise. It is even possible to slowly move the dewar in the Earth field (dynamic field compensation). Different noise cancellation procedures were optimized and compared employing a periodic signal source.

Bechstein, S.; Kim, I.-S.; Drung, D.; Novikov, I.; Schurig, Th

2010-06-01

200

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

PubMed

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

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

2011-01-01

201

99mTc-Labeled HYNIC-DAPI Causes Plasmid DNA Damage with High Efficiency  

PubMed Central

99mTc is the standard radionuclide used for nuclear medicine imaging. In addition to gamma irradiation, 99mTc emits low-energy Auger and conversion electrons that deposit their energy within nanometers of the decay site. To study the potential for DNA damage, direct DNA binding is required. Plasmid DNA enables the investigation of the unprotected interactions between molecules and DNA that result in single-strand breaks (SSBs) or double-strand breaks (DSBs); the resulting DNA fragments can be separated by gel electrophoresis and quantified by fluorescent staining. This study aimed to compare the plasmid DNA damage potential of a 99mTc-labeled HYNIC-DAPI compound with that of 99mTc pertechnetate (99mTcO4?). pUC19 plasmid DNA was irradiated for 2 or 24 hours. Direct and radical-induced DNA damage were evaluated in the presence or absence of the radical scavenger DMSO. For both compounds, an increase in applied activity enhanced plasmid DNA damage, which was evidenced by an increase in the open circular and linear DNA fractions and a reduction in the supercoiled DNA fraction. The number of SSBs elicited by 99mTc-HYNIC-DAPI (1.03) was twice that caused by 99mTcO4? (0.51), and the number of DSBs increased fivefold in the 99mTc-HYNIC-DAPI-treated sample compared with the 99mTcO4? treated sample (0.02 to 0.10). In the presence of DMSO, the numbers of SSBs and DSBs decreased to 0.03 and 0.00, respectively, in the 99mTcO4– treated samples, whereas the numbers of SSBs and DSBs were slightly reduced to 0.95 and 0.06, respectively, in the 99mTc-HYNIC-DAPI-treated samples. These results indicated that 99mTc-HYNIC-DAPI induced SSBs and DSBs via a direct interaction of the 99mTc-labeled compound with DNA. In contrast to these results, 99mTcO4? induced SSBs via radical formation, and DSBs were formed by two nearby SSBs. The biological effectiveness of 99mTc-HYNIC-DAPI increased by approximately 4-fold in terms of inducing SSBs and by approximately 10-fold in terms of inducing DSBs. PMID:25098953

Kotzerke, Joerg; Punzet, Robert; Runge, Roswitha; Ferl, Sandra; Oehme, Liane; Wunderlich, Gerd; Freudenberg, Robert

2014-01-01

202

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

SciTech Connect

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

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

2006-02-02

203

99mTc-MIBI radio-guided minimally invasive parathyroid surgery planned on the basis of a preoperative combined 99mTc-pertechnetate/99mTc-MIBI and ultrasound imaging protocol.  

PubMed

The aims of this study were: (a) to define the accuracy of a preoperative parathyroid imaging protocol based on the combination of technetium-99m pertechnetate/technetium-99m methoxyisobutylisonitrile (99mTcO4/ 99mTc-MIBI) scan and neck ultrasound (US) in selecting patients with primary hyperparathyroidism (pHPT) eligible for a limited neck exploration, and (b) to investigate the potential role of the intraoperative gamma probe (IGP) in radio-guided minimally invasive surgery. 99mTcO4/99mTc-MIBI subtraction scan was performed by means of potassium perchlorate administration with the aim of effecting rapid 99mTcO4 wash-out from the thyroid. Minimally invasive surgery using an IGP was commenced some minutes following the injection of a low, 70 MBq, 99mTc-MIBI dose. Intraoperative PTH (i-PTH) was measured. On the basis of preoperative imaging, 21 pHPT consecutive patients were selected for a limited neck dissection. In 18 of them, a single parathyroid adenoma was found at surgery and IGP allowed performance of parathyroidectomy through a small, 2-2.5 cm, skin incision with a relatively short surgical duration (mean 38 min). i-PTH rapidly normalised in all cases. In two patients, a parathyroid carcinoma was diagnosed at surgery; consequently, a wide neck exploration associated with a near-total thyroidectomy was performed. No loco-regional metastatic lesions were found and i-PTH rapidly normalised after carcinoma excision. In one patient, i-PTH remained elevated after removal of the enlarged parathyroid gland which was localised by 99mTcO4/99mTc-MIBI scan and US. A bilateral exploration was needed to remove a contralateral enlarged parathyroid gland. Combined, 99mTcO4/99mTc-MIBI scan and US imaging correctly localised a single parathyroid gland in 20/21 patients (95.2%); thus, this protocol appears to be accurate enough for the preoperative selection of pHPT patients eligible for limited neck surgery. Moreover, in these selected patients the IGP seems to be helpful in performing radio-guided minimally invasive surgery. PMID:11007510

Casara, D; Rubello, D; Piotto, A; Pelizzo, M R

2000-09-01

204

99mTc-3P4-RGD2 Scintimammography in the Assessment of Breast Lesions: Comparative Study with 99mTc-MIBI  

PubMed Central

Purpose To compare the potential application of 99mTc-3P-Arg-Gly-Asp (99mTc-3P4-RGD2) scintimammography (SMM) and 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) SMM for the differentiation of malignant from benign breast lesions. Method Thirty-six patients with breast masses on physical examination and/or suspicious mammography results that required fine needle aspiration cytology biopsy (FNAB) were included in the study. 99mTc-3P4-RGD2 and 99mTc-MIBI SMM were performed with single photon emission computed tomography (SPECT) at 60 min and 20 min respectively after intravenous injection of 738±86 MBq radiotracers on a separate day. Images were evaluated by the tumor to non-tumor localization ratios (T/NT). Receiver operating characteristic (ROC) curve analysis was performed on each radiotracer to calculate the cut-off values of quantitative indices and to compare the diagnostic performance for the ability to differentiate malignant from benign diseases. Results The mean T/NT ratio of 99mTc-3P4-RGD2 in malignant lesions was significantly higher than that in benign lesions (3.54±1.51 vs. 1.83±0.98, p<0.001). The sensitivity, specificity, and accuracy of 99mTc-3P4-RGD2 SMM were 89.3%, 90.9% and 89.7%, respectively, with a T/NT cut-off value of 2.40. The mean T/NT ratio of 99mTc-MIBI in malignant lesions was also significantly higher than that in benign lesions (2.86±0.99 vs. 1.51±0.61, p<0.001). The sensitivity, specificity and accuracy of 99mTc-MIBI SMM were 87.5%, 72.7% and 82.1%, respectively, with a T/NT cut-off value of 1.45. According to the ROC analysis, the area under the curve for 99mTc-3P4-RGD2 SMM (area?=?0.851) was higher than that for 99mTc-MIBI SMM (area?=?0.781), but the statistical difference was not significant. Conclusion 99mTc-3P4-RGD2 SMM does not provide any significant advantage over the established 99mTc-MIBI SMM for the detection of primary breast cancer. The T/NT ratio of 99mTc-3P4-RGD2 SMM was significantly higher than that of 99mTc-MIBI SMM. Both tracers could offer an alternative method for elucidating non-diagnostic mammograms. PMID:25250628

Gao, Shi; Ji, Tiefeng; Wen, Qiang; Song, Yan; Zhu, Lei; Xu, Zheli; Liu, Lin

2014-01-01

205

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

PubMed

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

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

2011-03-01

206

Synthesis, Structure Elucidation, and Redox Properties of [superscript 99]Tc Complexes of Lacunary Wells-Dawson Polyoxometalates: Insights into Molecular [superscript 99]Tc-Metal Oxide Interactions  

SciTech Connect

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

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

2011-11-17

207

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

SciTech Connect

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

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

2011-01-10

208

Transmulation of 99 Tc and preparation of artificial stable ruthenium: II. Examination of Tc-Ru alloys obtained by irradiation of metallic technetium  

Microsoft Academic Search

The Tc Ru alloys prepared by reactor irradiation of metallic Tc were examined by X-ray diffraction analysis. The distribution\\u000a of Ru throughout the depth of the irradiated sample was examined by X-ray spectral microanalysis and spectrophotometry at\\u000a layer-by-layer dissolution of the sample. Nonuniform distribution of Ru throughout the depth of the irradiated sample was\\u000a revealed, with increased Ru content in

S. V. Tomilin; V. M. Radchenko; K. V. Rotmanov; L. S. Lebedeva; A. G. Yakovenko; E. M. Pichuzhkina; F. N. Kryukov; O. N. Nikitin

2007-01-01

209

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

210

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

211

THE GLOBAL ATMOSPHERIC TRANSPORT AND TROPOSPHERIC CHEMISTRY MODEL TM2/TC1: USER MANUAL AND  

E-print Network

THE GLOBAL ATMOSPHERIC TRANSPORT AND TROPOSPHERIC CHEMISTRY MODEL TM2/TC1: USER MANUAL to chemical processes. The tropospheric background chemistry (CH 4 \\Gamma CO \\Gamma O 3 \\Gamma NO x \\Gamma OH FOR TROPOSPHERIC CHEMISTRY MODULE TC1 FOR TM2 3 TABLE I Reactions and rate constants [cm 3 s \\Gamma1 ] used

Haak, Hein

212

Abnormal focal 99mTc-DMSA uptake in the lung--report of two cases.  

PubMed

Extrarenal uptake of 99mTc-DMSA is a rare finding, which has been described in some unusual conditions as bone metastasis, aortic aneurysm and hemangioma. The purpose of this report is to present two cases of abnormal 99mTc-DMSA uptake in the lungs, which remained unexplained even after radiologic assessment. PMID:24610651

Pirayesh, Elahe; Amoui, Mahasti; Halimi Asl, Ali Asghar; Assadi, Majid

2014-01-01

213

Imaging endocarditis with Tc-99m-labeled antibody--an experimental study: concise communication  

SciTech Connect

The sensitivity and specificity of Tc-99m-labeled antibacterial antibody (Tc-99m Ab) for detecting bacterial endocarditis were evaluated in an experimental model. Rabbit-produced antistaphylococcal antibody was extracted using Rivanol and chemically labeled with Tc-99m. This Tc-99m Ab was injected intravenously in New Zealand rabbits 24 hr after producing Staphylococcus aureus endocarditis of the aortic valve. Imaging and tissue analyses were performed on the following day. All 11 animals developed S. aureus aortic-valve vegetations and showed increased uptake of Tc-99m Ab at the aortic valve, 118 times higher than at the uninfected tricuspid valve. Although high hepatic radioactivity and anatomic uncertainties interfered with in vivo delineation of these lesions, images of the excised hearts showed all affected valves. Two rabbits inoculated with Escherichia coli did not develop endocarditis and had little uptake of Tc-99m Ab, while six rabbits with enterococcal endocarditis had no uptake of the Tc-99m Ab in their vegetations. The findings suggest potential value of Tc-99m Ab on the rapid diagnosis of endocarditis.

Wong, D.W.; Dhawan, V.K.; Tanaka, T.; Mishkin, F.S.; Reese, I.C.; Thadepalli, H.

1982-03-01

214

The inducible costimulator augments tc17 cell responses to self and tumor tissue.  

PubMed

The inducible costimulator (ICOS) plays a key role in the development of Th17 cells, but its role in the development and antitumor activity of IL-17-producing CD8(+) T cells (Tc17) remains unknown. We found that ICOS costimulation was important for the functional maintenance, but not differentiation, of Tc17 cells in vitro. Blocking the ICOS pathway using an antagonist mAb or by using recipient mice genetically deficient in the ICOS ligand reduced the antitumor activity of adoptively transferred Tc17 cells. Conversely, activating Tc17 cells with an ICOS agonist in vitro enhanced their capacity to eradicate melanoma and induce autoimmune vitiligo when infused into mice. However, ICOS stimulation did not augment the antitumor activity of IL-2 expanded T cells. Additional investigation revealed that ICOS stimulation not only increased IL-2R?, CXCR3, and IL-23R expression on Tc17 cells, but also dampened their expression of suppressive molecule CD39. Although Tc17 cells activated with an ICOS agonist cosecreted heightened IL-17A, IL-9, and IFN-?, their therapeutic effectiveness was critically dependent on IFN-? production. Depletion of IL-17A and IL-9 had little impact on antitumor Tc17 cells activated with an ICOS agonist. Collectively, our work reveals that the ICOS pathway potentiates the antitumor activity of adoptively transferred Tc17 cells. This work has major implications for the design of vaccine, Ab and cell-based therapies for autoimmunity, infectious disease, and cancer. PMID:25576595

Nelson, Michelle H; Kundimi, Sreenath; Bowers, Jacob S; Rogers, Carolyn E; Huff, Logan W; Schwartz, Kristina M; Thyagarajan, Krishnamurthy; Little, Elizabeth C; Mehrotra, Shikhar; Cole, David J; Rubinstein, Mark P; Paulos, Chrystal M

2015-02-15

215

Electron pockets in the Fermi surface of hole-doped high-Tc superconductors  

E-print Network

near the onset of antiferromagnetic order6,7 . Comparison with materials of the La2CuO4 family in those materials, pointing to a generic property of high- transition-temperature (Tc) superconductorsLETTERS Electron pockets in the Fermi surface of hole-doped high-Tc superconductors David LeBoeuf1

Taillefer, Louis

216

Preparation of 99mTc-Clomiphene Citrate as a Novel Agent for Breast Cancer Imaging  

PubMed Central

The aim of this work was to develop a novel 99mTc-labelled derivative based on triphenylethylene for breast cancer imaging. 99mTc-Clomiphene was obtained with a radiochemical yield of 94.4% by adding 99mTc to 1.5?mg Clomiphene citrate in the presence of 10??g SnCl2 at pH 7. The optimization of the labeling yield of Clomiphene citrate, with 99mTc, is described. The reaction parameters that affect the labeling yield were studied to optimize the labeling conditions. Radiochemical purity of the final product has been verified by means of paper chromatography and paper electrophoresis. Ehrlich Ascites Carcinoma (EAC) as a model of breast cancer cells was injected intraperitoneally (IP) to produce ascites and intramuscularly (IM) to produce solid tumor. Biodistribution study was carried out by the injecting solution of 99mTc-Clomiphene in normal and tumor bearing mice. The uptake in ascites was over 12.5 % injected dose per gram tissue body weight, at 1hr after injection and above 12% in solid tumor. The T/NT value for 99mTc-Clomiphene complex was found to be 5.5 ± 0.4 which was higher than that of the commercially available 99mTc-MIBI. This data revealed the localization of tracer in tumor tissue with high percent sufficient to use 99mTc-Clomiphene as a promising tool for the diagnosis of breast cancer. PMID:23213567

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

2012-01-01

217

The Heavy Quark Free-Energy at T<Tc in AdS/QCD  

E-print Network

Starting with the modified AdS/QCD metric developed in Ref.[1] we use the Nambu-Goto action to obtain the free energy of a quark-antiquark pair at T<Tc, for which we show that the effective string tension goes to zero at Tc=154MeV.

K. Veshgini; E. Megias; J. Nian; H. J. Pirner

2009-11-09

218

In Vitro Evaluation of Tc-99m Radiopharmaceuticals for Gastric Emptying Studies  

PubMed Central

Objective: Gastrointestinal motility and functional motility disorders causing either delayed or accelerated gastric emptying (GE) may result in similar symptoms including nausea, vomiting, early satiety, fullness, bloating, and abdominal discomfort or pain. Hence, it is important to evaluate patients for both rapid and delayed GE in the same test. The gold standard technique to measure GE is scintigraphy by radiolabeled test meals. The aim of this study was to test alternative Tc-99m agents to label eggs as the solid meal and compare to Tc-99m sulfur colloid (SC) for gastric emptying studies. Methods: In search of alternative agents for gastric emptying studies, we mixed and fried eggs with four different particulate compounds (Tc-99m labeled SC, tin colloid, nanocolloid and MAA), as well as with free pertechnetate and Tc-99m DTPA. We then measured the stability of these compounds in simulated gastric juice. Results: Our experiments demonstrated that in addition to Tc-99m sulfur colloid;Tc-99m MAA, Tc-99m nanocolloid and Tc-99m tin colloid also appear to make stable complexes with eggs in acidic environment. Conclusion: Therefore, these agents may be used for gastric emptying studies which could be more practical in routine conditions. Conflict of interest:None declared. PMID:24653931

Ertay, Türkan; Do?an, Amet Semih; Ülker, Özden; Durak, Hatice

2014-01-01

219

A unique parameterization of the QCD equation of state below and above T_c  

E-print Network

We present a unique parameterization of the equation of state of strongly interacting matter in the temperature interval 0.6 T_c ... 3 T_c at \\mu = 0 within a quasi-particle model based on quark and gluon degrees of freedom. The extension to non-vanishing baryon-chemical potential is discussed.

M. Bluhm; B. Kampfer; G. Soff

2004-06-11

220

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

Microsoft Academic Search

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

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

2005-01-01

221

DIFFRACTION SPECTRUM OF LATTICE GAS MODELS ABOVE Tc MICHAEL BAAKE AND BERND SING  

E-print Network

DIFFRACTION SPECTRUM OF LATTICE GAS MODELS ABOVE Tc MICHAEL BAAKE AND BERND SING ABSTRACT. The diffraction spectra of lattice gas models on d with finite-range ferromagnetic two-body interactions above Tc or with certain rates of decay of the potential are considered. We show that these diffraction spectra almost

Bielefeld, University of

222

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. PMID:23596509

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

223

Buffer layers for high-Tc thin films on sapphire  

NASA Technical Reports Server (NTRS)

Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

1992-01-01

224

Modeling collision probability for Earth-impactor 2008 TC3  

E-print Network

We study the evolution of the Earth collision probability of asteroid 2008 TC3 using a short observational arc and small numbers of observations. To assess impact probability, we use techniques that rely on the orbital-element probability density function characterized using both Markov-chain Monte-Carlo orbital ranging and Monte-Carlo ranging. First, we evaluate the orbital uncertainties for the object from the night of discovery onwards and examine the collapse of the orbital-element distributions in time. Second, we examine the sensitivity of the results to the assumed astrometric noise. Each of the orbits obtained from the MCMC ranging method is propagated into the future (within chosen time bounds of the expected impact), and the collision probability is calculated as a weighted fraction of the orbits leading to a collision from the Earth. We compare the results obtained with both methods.

Oszkiewicz, Dagmara; Virtanen, Jenni; Granvik, Mikael; Bowell, Edward

2012-01-01

225

Modeling collision probability for Earth-impactor 2008 TC3  

NASA Astrophysics Data System (ADS)

We study the evolution of the Earth collision probability of asteroid 2008 TC3 using a short observational arc and small numbers of observations. To assess impact probability, we use techniques that rely on the orbital-element probability density function characterized using both Markov-chain Monte-Carlo orbital ranging and Monte-Carlo ranging. First, we evaluate the orbital uncertainties for the object from the night of discovery onwards and examine the collapse of the orbital-element distributions in time. Second, we examine the sensitivity of the results to the assumed astrometric noise. Each of the orbits obtained from the MCMC ranging method is propagated into the future (within chosen time bounds of the expected impact), and the collision probability is calculated as a weighted fraction of the orbits leading to a collision from the Earth. We compare the results obtained with both methods.

Oszkiewicz, D.; Muinonen, K.; Virtanen, J.; Granvik, M.; Bowell, E.

2012-12-01

226

High- Tc superconductors and AC loss in electrotechnical devices  

NASA Astrophysics Data System (ADS)

To replace conventional normal conducting solutions in electrotechnical devices, high- Tc superconductors must offer distinct economical and technical benefits in terms of lower overall loss, volume and weight. Based on AC loss theory we design appropriate 50 Hz reference conductors for cables, transformers and other applications, calculate admissible limits for the conductor variables filament diameter, twist and matrix resistance and compare this to the present state of Bi-2223-tape conductors and AC loss measurements. Further the influence of perpendicular AC field components on losses is addressed. High current devices will require multistrand conductors, where nonuniform current distribution due to unbalanced magnetic coupling may result in partial saturation and enhanced losses. As an example we discuss the multilayer HTSC-cable and present a solution based on a `zero flux condition' for azimuthal and axial magnetic fields.

Ries, Günter; Leghissa, Martino; Rieger, Jürgen; Wiezorek, Jan; Oomen, Marijn

1998-12-01

227

Evolution and Exploration of Asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

We will discuss ongoing work to fully explore the diversity of materials contained in asteroid 2008 TC3, the small 4-m sized asteroid that was observed in space before hitting Earth on October 7, 2008. A small part of the asteroid was recovered in the form of the Almahata Sitta meteorites two months later. The recovered meteorites were mostly ureilites, but very unexpectedly 20-30 percent of other meteorite types were also recovered. Those included enstatite and ordinary chondrites that became part of the Ureilite Parent Body's daughter asteroids during the evolutionary pathway from the terrestrial region to the asteroid belt. An update will be given on ongoing and projected research into the Almahata Sitta strewnfield and the analysis of the individual meteorites by members of the Almahata Sitta consortium.

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

2011-12-01

228

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

229

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

SciTech Connect

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

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

2009-05-15

230

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. PMID:19136468

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

2009-01-01

231

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 “dissipation-less” technologies is that we lack a comprehensive perception of all the mechanisms which govern high-Tc superconductivity. Controversial in nature, “charge striping” 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

232

[Tc1-mediated contact sensitivity reaction, its mechanism and regulation].  

PubMed

The contact hypersensitivity reaction (CHS) to haptens is a classic example of cell-mediated immune response. In the effector phase, two stages can be distinguished: an early component, that appears only 2 hours after subsequent contact with the hapten, and the late component that develops approximately 24 hours later which is mediated by TCR??+ cells. The effector lymphocytes may be CD4+ T helper 1 (Th1) cells or CD8+ T cytotoxic 1 (Tc1) cells, which depends on the employed hapten and/or mice strain. NKT lymphocytes play the crucial role in the CHS initiation, by supporting B1 cells in the antigen-specific IgM antibodies production. The development of an early component is essential for the recruitment of T effector (Teff) cells to the side of hapten deposition and for the complete expansion of inflammatory reaction. The CHS reaction is under T regulatory (Treg) cells control, both in the induction phase as well as in the effector phase. A new view of a negative regulation of the Tc1 mediated CHS response is based on the suppression induced by epicutaneous (EC) application of protein antigen. The DNP-BSA skin application, on a gauze patch, leads to a state of immunosuppression. This maneuver results in rising the population of Treg cells with TCR??+CD4+CD25+Foxp3+ phenotype. The mechanism of suppression requires direct contact between Treg cells and Teff cells and the participation of CTLA-4 molecule is also necessary. The described method of evoking immune tolerance via EC immunization may contribute to elaborate a new method of allergic contact dermatitis therapy. This is because of its effectiveness, ease of induction and non-invasive protein antigen application. PMID:25055034

Zemelka-Wi?cek, Magdalena; Szczepanik, Marian

2014-01-01

233

The synthesis and structural characterization of the technetium nitrosyl complexes [TcCl(NO)(SC5H4N)(PPh3)2] and [Tc(NO)(SC5H4N)2(PPh3)  

PubMed Central

The reaction of the Tc(I) complex [Tc(NO)Cl2(HOMe)(PPh3)2] with stoichiometric amounts of 2-mercatopyridine and a proton scavenger yields [Tc(NO)Cl(Spy)(PPh3)2] or [Tc(NO)(Spy)2(PPh3)], depending upon quantities of ligands employed. These two complexes have been structurally characterized. The small bite angles of the bidentate mercaptopyridine ligands cause significant deviation from octahedral coordination geometry. PMID:23750048

Nicholson, Terrence L.; Mahmood, Ashfaq; Muller, Peter; Davison, Alan; Storm-Blanchard, Shannon; Jones, Alun G.

2011-01-01

234

Relationship between SST in the equatorial Eastern Pacific and TC frequency that affects Korea  

NASA Astrophysics Data System (ADS)

This study analyzed that there was a strong negative correlation between sea surface temperature (SST) in the equatorial Eastern Pacific and tropical cyclone (TC) frequency that affects Korea in summer season in 1951 to 2012. Then, 12 years that had the highest region-averaged SST values in the equatorial Eastern Pacific (warm SST years) and 12 years that had the lowest SST values (cold SST years) were selected, followed by analyzing average difference between two groups to identify any causes of possible correlation between SST in the equatorial Eastern Pacific and TC frequency. In the warm SST years, not only TC frequency that affected Korea but also TC genesis frequency was low, as well as TC intensity. A difference of 500 and 850 hPa streamlines between two groups showed that anomalous northwesterlies were strengthened in Korea due to anomalous cyclonic circulations developed in the mid-latitude region in East Asia, so that such anomalous steering flows played a role in preventing TCs from moving to Korea. Furthermore, anomalous anticyclonic circulations were strengthened in the east of Taiwan, which was related to weakening of the monsoon trough, thereby causing lowering TC genesis frequency in the warm SST years. In addition, as anomalous cyclonic circulations were strengthened in the southeast quadrant of the tropical and subtropical western North Pacific, it created high TC genesis frequency in the sea in the warm SST years. Low TC frequency, low TC genesis frequency, and low TC intensity that affected Korea in the warm SST years were clearly seen by the analysis of differences between two groups with respect to 500 and 850 hPa air temperature, 600 hPa relative humidity, precipitable water, 200-850 hPa vertical wind shear, and sea surface temperature.

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

2014-07-01

235

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

236

Incorporation and retention of 99-Tc(IV) in magnetite under high pH conditions.  

PubMed

Technetium incorporation into magnetite and its behavior during subsequent oxidation has been investigated at high pH to determine the technetium retention mechanism(s) on formation and oxidative perturbation of magnetite in systems relevant to radioactive waste disposal. Ferrihydrite was exposed to Tc(VII)(aq) containing cement leachates (pH 10.5-13.1), and crystallization of magnetite was induced via addition of Fe(II)aq. A combination of X-ray diffraction (XRD), chemical extraction, and X-ray absorption spectroscopy (XAS) techniques provided direct evidence that Tc(VII) was reduced and incorporated into the magnetite structure. Subsequent air oxidation of the magnetite particles for up to 152 days resulted in only limited remobilization of the incorporated Tc(IV). Analysis of both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data indicated that the Tc(IV) was predominantly incorporated into the magnetite octahedral site in all systems studied. On reoxidation in air, the incorporated Tc(IV) was recalcitrant to oxidative dissolution with less than 40% remobilization to solution despite significant oxidation of the magnetite to maghemite/goethite: All solid associated Tc remained as Tc(IV). The results of this study provide the first direct evidence for significant Tc(IV) incorporation into the magnetite structure and confirm that magnetite incorporated Tc(IV) is recalcitrant to oxidative dissolution. Immobilization of Tc(VII) by reduction and incorporation into magnetite at high pH and with significant stability upon reoxidation has clear and important implications for limiting technetium migration under conditions where magnetite is formed including in geological disposal of radioactive wastes. PMID:25236360

Marshall, Timothy A; Morris, Katherine; Law, Gareth T W; Mosselmans, J Frederick W; Bots, Pieter; Parry, Stephen A; Shaw, Samuel

2014-10-21

237

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

238

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. PMID:25026264

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

2014-01-01

239

Ascophyllan purified from Ascophyllum nodosum induces Th1 and Tc1 immune responses by promoting dendritic cell maturation.  

PubMed

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. PMID:25026264

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

2014-07-01

240

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

241

Cationic lipophilic complexes of /sup 99/ /SUP m/ Tc and their use for myocardial and hepatobiliary imaging  

SciTech Connect

A method of imaging organs with /sup 99/ /SUP m/ Tc radiopharmaceuticals, especially of hepatobiliary imaging and negative myocardial infarct imaging in a mammal which comprises administering to the mammal a hepatobiliary or myocardial imaging amount of a cationic lipophilic complex of Tc-99m and detecting the Tc-99m complex in the mammal. A method for the preparation of cationic lipophilic complexes of Tc-99m.

Deutsch, E. A.; Glavan, K. A.

1984-12-18

242

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

243

Extremely strong thermohaline sources/sinks generated by diagnostic initialization  

NASA Astrophysics Data System (ADS)

One difficulty for ocean modeling is the lack of velocity data for specifying the initial condition. Diagnostic initialization is widely used; it integrates the model from known temperature (Tc) and salinity (Sc) and zero velocity fields while holding (Tc, Sc) unchanged. After a period (around 30 days) of the diagnostic run, the velocity field (Vc) is established, and (Tc, Sc, Vc) fields are then treated as the initial conditions for the prognostic numerical modeling. During the diagnostic initialization period, the heat and salt `source/sink' terms are generated at each time step. Maximum time rates of absolute change of the monthly mean T, S (0.1°/day, 0.1 ppt/day) are taken as the standard measures to identify the strength of the thermohaline `sources/sinks'. Twenty four times of the standard measures (0.1°/hr, 0.1 ppt/hr) represent strong `sources/sinks'. Ten times of the strong `sources/sinks' (1°/hr, 1 ppt/hr) represent extremely strong `sources/sinks'. The Princeton Ocean Model implemented for the Japan/East Sea is used to demonstrate the existence of extremely strong thermohaline sources and sinks generated by the diagnostic initialization with the annual mean Tc, Sc from the Navy's Global Digital Environmental Model. The effects of extremely strong and spatially nonuniform initial heating/cooling (salting/freshening) rates on thermohaline and velocity fields need to be further investigated.

Chu, Peter C.; Lan, Jian

2003-03-01

244

Hydrogen Isotope Measurements of Organic Acids and Alcohols by Pyrolysis-GC-MS-TC-IRMS  

NASA Technical Reports Server (NTRS)

One possible process responsible for methane generation on Mars is abiotic formation by Fischer-Tropsch-type (FTT) synthesis during serpentinization reactions. Measurement of carbon and hydrogen isotopes of intermediary organic compounds can help constrain the origin of this methane by tracing the geochemical pathway during formation. Of particular interest within the context of this work is the isotopic composition of organic intermediaries produced on the surfaces of mineral catalysts (i.e. magnetite) during hydrothermal experiments, and the ability to make meaningful and reproducible hydrogen isotope measurements. Reported here are results of experiments to characterize the hydrogen isotope composition of low molecular weight organic acids and alcohols. The presence of these organic compounds has been suggested by others as intermeadiary products made during mineral surface catalyzed reactions. This work compliments our previous study characterizing the carbon isotope composition of similar low molecular weight intermediary organic compounds (Socki, et al, American Geophysical Union Fall meeting, Abstr. #V51B-2189, Dec., 2010). Our hydrogen isotope measurements utilize a unique analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-High Temperature Conversion-Isotope Ratio Mass Spectrometry (Py-GC-MS-TC-IRMS). Our technique is unique in that it carries a split of the pyrolyzed GC-separated product to a Thermo DSQ-II? quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of separated organic compounds, therefore both chemical and isotopic measurements can be carried out simultaneously on the same sample.

Socki, Richard A.; Fu, Qi; Niles, Paul B.

2011-01-01

245

Wind Generator  

NSDL National Science Digital Library

Windmills have been used for hundreds of years to collect energy from the wind in order to pump water, grind grain, and more recently generate electricity. There are many possible designs for the blades of a wind generator and engineers are always trying new ones. Design and test your own wind generator, then try to improve it by running a small electric motor connected to a voltage sensor.

Consortium, The C.

2012-05-21

246

Effects of mutant Ran/TC4 proteins on cell cycle progression.  

PubMed Central

Ran/TC4, a member of the RAS gene superfamily, encodes an abundant nuclear protein that binds and hydrolyzes GTP. Transient expression of a Ran/TC4 mutant protein deficient in GTP hydrolysis blocked DNA replication, suggesting a role for Ran/TC4 in the regulation of cell cycle progression. To test this possibility, we exploited an efficient transfection system, involving the introduction of cDNAs in the pMT2 vector into 293/Tag cells, to analyze phenotypes associated with mutant and wild-type Ran/TC4 expression. Expression of a Ran/TC4 mutant protein deficient in GTP hydrolysis inhibited proliferation of transfected cells by arresting them predominantly in the G2, but also in the G1, phase of the cell cycle. Deletion of an acidic carboxy-terminal hexapeptide from the Ran/TC4 mutant did not alter its nuclear localization but did block its inhibitory effect on cell cycle progression. These data suggest that normal progression of the cell cycle is coupled to the operation of a Ran/TC4 GTPase cycle. Mediators of this coupling are likely to include the nuclear regulator of chromosome condensation 1 protein and the mitosis-promoting factor complex. Images PMID:8196659

Ren, M; Coutavas, E; D'Eustachio, P; Rush, M G

1994-01-01

247

Demonstrating alcoholic cirrhosis of the liver by Tc-99m BIDA scintigram  

SciTech Connect

Six patients with decompensated cirrhosis of the liver underwent Tc-99m BIDA studies. All demonstrated 1) persistently high blood pool activity in the heart, lung, and soft tissue, 2) slow hepatic tracer uptake, 3) prolonged liver-to-bowel transit time, and 4) visualization of an enlarged spleen. Four of the six patients demonstrated evidence of ascites and in one patient there were visible collateral veins of the abdomen. These findings are due primarily to hepatic dysfunction and retaining Tc-99m BIDA in blood pool because of Tc-99m BIDA exclusively hepatic excretion and little or no alternative renal excretion. All six Tc-99m sulfur colloid studies were performed concomitantly. Except for bone marrow uptake and reversal of the normal liver-spleen ratio of radioactivity, the imaging abnormalities observed with Tc-99m BIDA were similar to those seen by Tc-99m SC. It is concluded that with Tc-99m BIDA studies, three of six abnormal findings, as described, suggest a decompensated stage of cirrhosis of the liver.

Shih, W.J.; DeLand, F.H.; Domstad, P.A.

1984-08-01

248

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

249

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

250

[Tc]-99m thyroid scintigraphy in congenital hypothyroidism screening program.  

PubMed

The aetiology of congenital hypothyroidism (CH) may be important in determining disease severity, outcome and treatment schedules because athyroid patients need higher treatment doses and close monitoring particularly early in life. The aim of this study was to evaluate thyroid scintigraphy (TS) findings in infants with CH and to determine the relationship of serum TSH and T4 values with thyroid agenesia, in an attempt to identify factors that may detect thyroid agenesia before treatment. Since August 2002 to April 2005, screening program for CH was carried out in the Isfahan University of Medical Sciences and Health Services, Isfahan, Iran. Screening was performed by measuring both the serums T4 and TSH concentration at day 3-7 of birth. Full-term newborns were recalled based on a serum TSH >20 mIU/l or serum T4 < 6.5 microg/dl and premature newborns based on T4 level by weight and TSH level by age. After repeating the laboratory test and clinical evaluation, Tc-99m TS was recommended for all infants with suspected CH before thyroxin replacement therapy. On the basis of Tc-99m TS, the thyroid gland was classified as normal scan, ectopic, goiter and athyrosis. TS results were compared with serum T4 and TSH levels. Of 93 381 newborns screened over a period of nearly 3 years, 262 neonates were found to have CH. The overall incidence of CH was 1 : 357 live births with a female/male ratio (F/M) of 1.4/1. Thyroid scan was performed on 116 (54%) of the infants with CH; of them, 33 cases (28.4%) were athyrotic (F/M = 0.8/1) while seven infants (6%) had ectopic thyroid (F/M = 1.3/1) and 76 cases (65.6%) had a normal thyroid scan (F/M = 1.5/1). Infants with the absence of thyroid in TS had significantly higher TSH value in comparison with those with ectopic or normal TS (116.3 +/- 109.64 vs. 108.10 +/- 62.92 or 55.35 +/- 48.26 mIU/l, respectively, P < 0.0001). Although not statistically different, the mean T4 level was higher in normal TS group than in ectopic and athyrotic groups (8.03 +/- 3.48 vs. 6.36 +/- 5.57 or 5.04 +/- 3 microg/dl, respectively, P = 0.09). We conclude that Tc-99m TS is a useful diagnostic tool for the initial investigation of suspected CH and considering the correlation of TS results with blood TSH levels, proper management and close monitoring of hypothyroid infants with severe hormonal alterations is necessary for the detection of thyroid agenesia. PMID:16943215

Iranpour, R; Hashemipour, M; Amini, M; Talaei, S M; Kelishadi, R; Hovsepian, S; Haghighi, S; Khatibi, Kh

2006-12-01

251

A 99mTc(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

252

Labeling, Stability and Biodistribution Studies of 99mTc-cyclized Tyr3-octreotate Derivatives  

PubMed Central

Introduction To probe the interplay between radiotracer stability and somatostatin receptor affinity, Tyr3-octreotate and six variations of its peptide sequence, for which the Re-cyclized products were previously reported, were radiolabeled with 99mTc and investigated for their in vitro stability. Methods Radiolabeling of the peptides was effected by ligand exchange from 99mTc-glucoheptonate, and the desired products were purified by radio-RP-HPLC. The in vitro stability in phosphate-buffered saline, mouse serum, and cysteine solutions at physiological temperature and pH for all seven 99mTc-cyclized peptides was determined by radio-RP-HPLC and radio-TLC. Normal CF-1 mouse biodistribution studies were performed for three of the 99mTc-cyclized peptides. Results Based on the fully characterized Re-cyclized peptide analogues, four 99mTc-coordination motifs were proposed for the 99mTc-cyclized peptides. Technetium-99m-cyclized Tyr3-octreotate derivatives with N2S2 metal coordination modes and large metal ring sizes were susceptible to oxidation and loss of 99mTc in the form of 99mTcO4?, as evidenced by their instability in the various solutions under physiological conditions (15–58% intact at 24 h). As anticipated, the addition of a third cysteine to the sequence stabilized the 99mTc metal coordination, and peptides with NS3 coordination modes remained >85% intact out to 24 h. No significant differences were observed in the biodistribution studies performed with three peptides of varying stabilities. Conclusions Improvements in stability were not sufficient to outweigh the low somatostatin receptor affinity for the peptides in this study. Further improvements in the peptide sequence and/or metal coordination are needed to result in a radiodiagnostic/radiotherapeutic pair for targeting the somatostatin receptor. PMID:21531292

Bigott-Hennkens, Heather M.; Dannoon, Shorouk F.; Noll, Samantha M.; Ruthengael, Varyanna C.; Jurisson, Silvia S.; Lewis, Michael R.

2010-01-01

253

Asialoglycoprotein-receptor-targeted hepatocyte imaging using 99mTc galactosylated chitosan.  

PubMed

This study investigated the usefulness of 99mTc hydrazinonicotinamide-galactosylated chitosan (HGC) in hepatocyte imaging. HGC was obtained by coupling the galactose moiety of both lactobionic acid and succinimidyl 6-hydrazinonicotinate hydrochloride (succinimidyl HYNIC). The coupled product was then radiolabeled with 99mTc using stannous chloride and tricine as reducing agent and coligand, respectively. Labeling efficiency was >90% both in room temperature and in serum up to 24 h after injection. The hepatic uptake properties of 99mTc HGC were studied in Balb/C mice. 99mTc HGC and 99mTc hydrazinonicotinamide chitosan (HC) were intravenously injected into mice, with receptor binding identified by coinjection with 9 and 14 mg of free galactose. Images were acquired with a gamma-camera. After injection via the tail vein of the mice, 99mTc HGC showed high selectivity for the liver, while 99mTc HC without a galactose group showed low liver uptake. In addition, the hepatic uptake of 99mTc HGC was blocked by coinjection of free galactose. Tissue distribution was determined at three different times (10, 60 and 120 min). The liver accumulated 13.16+/-2.72%, 16.11+/-5.70% and 16.55+/-2.28% of the injected dose per gram at 10, 60 and 120 min after injection, respectively. 99mTc HGC showed specific and rapid targeting of hepatocytes. It is a promising receptor-specific radiopharmaceutical with potential applications in liver imaging for the evaluation of hepatocytic function. PMID:16720245

Kim, Eun-Mi; Jeong, Hwan-Jeong; Kim, Se-Lim; Sohn, Myung-Hee; Nah, Jae-Woon; Bom, Hee-Seung; Park, In-Kyu; Cho, Chong-Su

2006-05-01

254

Lung 99mTc-MIBI scintigraphy: impact on diagnosis of solitary pulmonary nodule.  

PubMed

Most of today available non-invasive procedures cannot clearly determinate between benign and malignant solitary pulmonary nodules (SPN). The purpose of the study was to assess the possibility of using 99mTc labeled hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) to differentiate benign from malignant SPN. Sixty patients were included in the study if the CT scan showed indeterminate SPN. Prior to definitive diagnosis 99mTc-MIBI single photon emission computerized tomography (SPECT) was performed: early scan 10 minutes and delayed 60-120 minutes after the intravenous injection of 740 MBq 99mTc-MIBI using dual-headed Gamma camera. The results were considered positive if there was an increased accumulation of the radiopharmaceutical in the area of the lung corresponding to the location of the lesion. The mean nodule size ± SD measured on CT scan was 2.96 cm. Lung cancer was diagnosed in 30/60 patients (14 squamocellular, 10 adenocarcinoma, 3 large-cell and 3 microcellular lung carcinomas). Of the 30 patients with malignant lesions, 27 patients (90%) had positive 99mTc-MIBI scan results by qualitative assessment. Among benign lesions, 23/30 (76.7%) were negative on 99mTc-MIBI scan. The size and PH report of SPN is statistically significantly influencing on 99mTc-MIBI accumulation in the SPN (p<0.01). The sensitivity, specificity, accuracy, positive and negative predictive value were 90%, 76.6%, 79.4%, 88.5% and 83.3% respectively. 99mTc-MIBI SPECT is an inexpensive non-invasive diagnostic procedure which might be useful diagnostic modality in the evaluation of SPN. Easy availability and low cost makes 99mTc-MIBI SPECT an attractive method in evaluating SPN. PMID:21875420

Nikoletic, Katarina; Lucic, Silvija; Peter, Andrea; Kolarov, Violeta; Zeravica, Radmila; Srbovan, Dolores

2011-08-01

255

Comparison of Tc-99m pertechnetate images with dual-phase Tc 99m MIBI and SPECT images in primary hyperparathyroidism  

PubMed Central

Background: The purpose of this study was to evaluate the value of Tc-99m pertechnetate planar, dual-phase MIBI and MIBI-SPECT images in the determination and localization of parathyroid lesions. Materials and Methods: In this study, 38 patients who underwent operation for primary hyperparathyroidism were included. Tc-99m pertechnetate planar-pinhole imaging of the neck and then MIBI planar and SPECT images in supine position was performed. Late SPECT images were acquired 120 minutes after the injection. Early and late MIBI images were quantitatively evaluated. Results: Of the 38 patients, 30 of them had adenoma, 2 patients had hyperplasia and 6 of them were normal on planar images. Thirty-four of 38 patients were positive on SPECT images. SPECT images of the patients with positive results were matched with pathology results. Conclusion: As a result, Tc-99m pertechnetate planar-pinhole, Tc-99m MIBI planar and SPECT images are useful for localization of parathyroid lesions especially in multinodular thyroid gland. However, US or CT images are necessary for more accurate localization and Tc-99m pertechnetate images are useful for interpreting and comparing with the early and late MIBI images. PMID:25143912

Sager, Sait; Shafipour, Hojjat; Asa, Sertac; Y?lmaz, Sabire; Teksöz, Serkan; Önsel, Çetin

2014-01-01

256

Simultaneous 99mTc-MDP/123I-MIBG tumor imaging using SPECT-CT: Phantom and constructed patient studies  

PubMed Central

Purpose: Authors’ goal is to evaluate the performance of simultaneous 99mTc-MDP/123I-MIBG tumor imaging with fast Monte-Carlo (MC) based joint iterative reconstruction as compared to sequential 99mTc-MDP and 123I-MIBG tumor imaging. Methods: Noise-free 99mTc and 123I SPECT projections were acquired separately using an anthropomorphic torso phantom modified to include a fillable tube around the lungs to mimic ribs. Additionally, 99mTc and 123I projections were acquired separately using a 1-cm spherical “tumor” placed at various distances from one detector. Tumor-present data were generated by adding tumor projections to the torso phantom data, which were scaled to the total counts in typical clinical studies. Twenty-five noise realizations were generated by adding Poisson noise to the projection data for each radionuclide. Dual-radionuclide data were synthesized by summing the 99mTc and 123I projections. Image reconstruction was performed using: (1) SR-OSEM, ordered subset expectation maximization (OSEM) without scatter correction (SC) using single-radionuclide (SR) data; (2) SR-MC-OSEM, OSEM with a fast MC-based SC using SR data; (3) DR-OSEM, OSEM without SC using dual-radionuclide (DR) data; and (4) DR-MC-JOSEM, joint OSEM with a fast MC-based SC using DR data. Ten 99mTc-MDP and ten 123I-MIBG data sets, which had tumors mathematically inserted, were also used to evaluate the performance of authors’ approach. For the phantom study, relative bias and relative standard deviation of tumor uptake were computed for each tumor using the tumor uptake in the noise-free single-radionuclide images, which were reconstructed by SR-MC-OSEM, as the gold standard. For both the phantom and constructed patient studies, mean contrast and standard deviation of contrast were computed for each tumor for both the single- and dual-radionuclide images. Additionally, contrast recovery was computed as the ratio between mean contrast and the mean contrast for SR-MC-OSEM. Results: For the phantom study, DR-MC-JOSEM yielded 2.7% on average relative bias of tumor uptake using the images, which were reconstructed from the noise-free SR data with SR-MC-OSEM, as the gold-standard. For both the phantom and constructed patient studies, DR-MC-JOSEM yielded 94.7% and 95.2% tumor contrast recovery on average using SR-MC-OSEM as the reference, in the phantom and constructed patient studies, respectively. DR-MC-JOSEM yielded comparable relative standard deviation of bias and standard deviation of contrast to SR-MC-OSEM. Conclusions: Simultaneous 99mTc-MDP/123I-MIBG tumor imaging using authors’ dual-radionuclide reconstruction approach yielded comparable image quality to sequential 99mTc-MDP and 123I-MIBG imaging. For patients who need to undergo both scans, authors’ approach offers perfectly registered dual-tracer images under identical conditions without compromising image quality, and reduces the imaging cost while increasing patient throughput. PMID:24089927

Rakvongthai, Yothin; Fakhri, Georges El; Lim, Ruth; Bonab, Ali A.; Ouyang, Jinsong

2013-01-01

257

The Effect of Morphine on Regional Cerebral Blood Flow Measured by 99mTc-ECD SPECT in Dogs  

PubMed Central

To gain insights into the working mechanism of morphine, regional cerebral blood flow (rCBF) patterns after morphine administration were assessed in dogs. In a randomized cross-over experimental study, rCBF was estimated with 99mTc-Ethylcysteinate Dimer single photon emission computed tomography in 8 dogs at baseline, at 30 minutes and at 120 minutes after a single bolus of morphine. Perfusion indices (PI) in the frontal, parietal, temporal and occipital cortex and in the subcortical and cerebellar region were calculated. PI was significantly decreased 30 min after morphine compared to baseline in the right frontal cortex. The left parietal cortex and subcortical region showed a significantly increased PI 30 min after morphine compared to baseline. No significant differences were noted for the other regions or at other time points. In conclusion, a single bolus of morphine generated a changing rCBF pattern at different time points. PMID:25295733

Adriaens, Antita; Peremans, Kathelijne; Waelbers, Tim; Vandermeulen, Eva; Croubels, Siska; Duchateau, Luc; Dobbeleir, André; Audenaert, Kurt; Eersels, Jos; Vermeire, Simon; De Spiegeleer, Bart; Polis, Ingeborgh

2014-01-01

258

Tc-cAPX, a cytosolic ascorbate peroxidase of Theobroma cacao L. engaged in the interaction with Moniliophthora perniciosa, the causing agent of witches' broom disease.  

PubMed

The level of hydrogen peroxide (H2O2) in plants signalizes the induction of several genes, including that of ascorbate peroxidase (APX-EC 1.11.1.11). APX isoenzymes play a central role in the elimination of intracellular H2O2 and contribute to plant responses to diverse stresses. During the infection process in Theobroma cacao by Moniliophthora perniciosa oxidative stress is generated and the APX action recruited from the plant. The present work aimed to characterize the T. cacao APX involved in the molecular interaction of T. cacao-M. perniciosa. The peroxidase activity was analyzed in protein extracts from cocoa plants infected by M. perniciosa and showed the induction of peroxidases like APX in resistant cocoa plants. The cytosolic protein of T. cacao (GenBank: ABR68691.2) was phylogenetically analyzed in relation to other peroxidases from the cocoa genome and eight genes encoding APX proteins with conserved domains were also analyzed. The cDNA from cytosolic APX was cloned in pET28a and the recombinant protein expressed and purified (rTc-cAPX). The secondary structure of the protein was analyzed by Circular Dichroism (CD) displaying high proportion of ?-helices when folded. The enzymatic assay shows stable activity using ascorbate and guaiacol as an electron donor for H2O2 reduction. The pH 7.5 is the optimum for enzyme activity. Chromatographic analysis suggests that rTc-cAPX is a homodimer in solution. Results indicate that the rTc-cAPX is correctly folded, stable and biochemically active. The purified rTc-cAPX presented biotechnological potential and is adequate for future structural and functional studies. PMID:24161755

Camillo, Luciana Rodrigues; Filadelfo, Ciro Ribeiro; Monzani, Paulo Sérgio; Corrêa, Ronan Xavier; Gramacho, Karina Peres; Micheli, Fabienne; Pirovani, Carlos Priminho

2013-12-01

259

High-Tc SQUID Magnetometers for Industrial Applications  

NASA Astrophysics Data System (ADS)

We have developed high-Tc SQUID magnetometers for use in a variety of industrial applications. Relatively inexpensive direct-coupled magnetometers have been developed for low-frequency applications including fetal-magnetocardiography. A manufacturable process has been developed to reproducibly fabricate high-resistance (up to 6 ?) SNS step-edge junctions with YBa_2Cu_3O_7-x as the superconductor and Ag-Au alloy as the normal metal. Magnetic field sensitivities at 77K of 22 ft/Hz^1/2 at 1 KHz and 32 ft/Hz^1/2 at 1 Hz have been achieved in a well-shielded laboratory environment. Current effort is focused on operation in an unshielded environment using flux dams(Milliken et al. Appl. Phys. Lett. 71 1857 (1997)) in conjunction with narrow superconducting pickup coils placed in parallel. An integrated magnetometer process has also been optimized for use in high-frequency applications. The integrated megnetometer utilizes two layers of YBa_2Cu_3O_7-x and one layer of deposited SrTiO_3, all on the same 24 mm x 5 mm substrate. The applications under development include the detection of the explosive material in non-metallic land mines using nuclear quadrupole resonance as well as the non-destructive evaluation of non-metallic composites using nuclear magnetic resonance. For operation in the MHz regime, these applications demand a high quality insulator layer and a robust SQUID that can withstand high current transients.

Diiorio, Mark; Yang, Kai-Yueh; Yoshizumi, Shozo; Haupt, Steven; Haran, Don; Koch, Roger; Lathrop, Dan; Trammel, Hoke

1998-03-01

260

Comparative study of organic metals and high-Tc cuprates  

NASA Astrophysics Data System (ADS)

The Bechgaard salts and the high Tc cuprates are described by two and three band models, respectively, with the lowest band (nearly) half filled. In organics the interactions are small, while in cuprates the repulsion Ud on the Cu-site is the largest energy. The Mott-AF state is stable in undoped materials in both cases. In the metallic phase of cuprates the Ud?? limit produces a moderate effective repulsion. The theories of the coherent SDW and charge-transfer correlations in the metallic phases of organics and cuprates are thus similar. In (undoped) organics those correlations are associated with commensurate 2kF SDW and 4kF bond or site modes. The corresponding modes in metallic cuprates are the incommensurate SDW and in particular Ox/Oy quadrupolar charge transfer with wave vector 2qSDW=q0+G. They are enhanced for dopings x>0, which bring the Fermi level close to the van Hove singularity. Strong coupling to the lattice associates the static incommensurate Ox/Oy charge transfer with collinear “nematic” stripes. In contrast to organics, the coherent correlations in cuprates compete with local d10?d9 quantum charge-transfer disorder.

Bariši?, S.; Bariši?, O. S.

2009-03-01

261

The impact and recovery of asteroid 2008 TC(3).  

PubMed

In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554-995 nm wavelength range, and designated 2008 TC(3) (refs 4-6). It subsequently hit the Earth. Because it exploded at 37 km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95 kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections. PMID:19325630

Jenniskens, P; Shaddad, M H; Numan, D; Elsir, S; Kudoda, A M; Zolensky, M E; Le, L; Robinson, G A; Friedrich, J M; Rumble, D; Steele, A; Chesley, S R; Fitzsimmons, A; Duddy, S; Hsieh, H H; Ramsay, G; Brown, P G; Edwards, W N; Tagliaferri, E; Boslough, M B; Spalding, R E; Dantowitz, R; Kozubal, M; Pravec, P; Borovicka, J; Charvat, Z; Vaubaillon, J; Kuiper, J; Albers, J; Bishop, J L; Mancinelli, R L; Sandford, S A; Milam, S N; Nuevo, M; Worden, S P

2009-03-26

262

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

263

The impact and recovery of asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554-995nm wavelength range, and designated 2008 TC3 (refs 4-6). It subsequently hit the Earth. Because it exploded at 37km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections.

Jenniskens, P.; Shaddad, M. H.; Numan, D.; Elsir, S.; Kudoda, A. M.; Zolensky, M. E.; Le, L.; Robinson, G. A.; Friedrich, J. M.; Rumble, D.; Steele, A.; Chesley, S. R.; Fitzsimmons, A.; Duddy, S.; Hsieh, H. H.; Ramsay, G.; Brown, P. G.; Edwards, W. N.; Tagliaferri, E.; Boslough, M. B.; Spalding, R. E.; Dantowitz, R.; Kozubal, M.; Pravec, P.; Borovicka, J.; Charvat, Z.; Vaubaillon, J.; Kuiper, J.; Albers, J.; Bishop, J. L.; Mancinelli, R. L.; Sandford, S. A.; Milam, S. N.; Nuevo, M.; Worden, S. P.

2009-03-01

264

Charge segregation model for superconducting correlations in cuprates above Tc  

NASA Astrophysics Data System (ADS)

We present a theoretical framework for understanding recent transverse field muon spin rotation (TF-µSR) experiments on cuprate superconductors in terms of localized regions of phase-coherent pairing correlations above the bulk superconducting transition temperature Tc. The local regions of phase coherence are associated with a tendency toward charge ordering, a phenomenon found recently in hole-doped cuprates. We use the Cahn–Hilliard equation as a means to phenomenologically model the inhomogeneous charge distribution of the electron system observed experimentally. For this system we perform self-consistent superconducting calculations using the Bogoliubov–deGennes method. Within this context we explore two possible scenarios: (i) the magnetic field is diamagnetically screened by the sum of varying shielding currents of isolated small-sized superconducting domains. (ii) These domains become increasingly correlated by Josephson coupling as the temperature is lowered and the main response to the applied magnetic field is from the sum of all varying tunneling currents. The results indicate that these two approaches may be used to simulate the TF-µSR data but case (ii) yields better agreement.

de Mello, E. V. L.; Sonier, J. E.

2014-12-01

265

High-{Tc} DC SQUID and flux transformer development  

SciTech Connect

A description is presented of the fabrication and properties of high {Tc} DC SQUIDS and flux transformers fabricated by dry processing of pulsed laser ablated YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (YBCO) thin films. SQUIDs have been fabricated with either bicrystal substrate or step edge junctions. For all devices fabricated thus far, measurements indicate a similar character to the flux noise spectra with a significant 1/f noise component below 100--500 Hz. The transfer function and energy sensitivities as a function of SQUID inductances in the range 60--200 pH have been measured for bicrystal DC SQUIDs and compared with estimates. Various techniques have been employed to improve the magnetic field sensitivity of the uncoupled DC SQUID toward more practical levels including the use of large area washers, single layer magnetometers and 3-level flux transformers fabricated from trilayers of YBCO/SrTiO{sub 3}/YBCO. The properties of open input coils are presented as well as the performance of closed loop transformers coupled via flip chip geometry to the SQUID washer. A white magnetic noise level of {approx} 130 fT rms/{radical}Hz above 200 Hz has been reached with a flux transformer with a 15 turn input coil and pick-up loop area of 13 mm{sup 2}.

Fife, A.A.; Angus, V.; Betts, K. [CTF Systems Inc., Port Coquitlam, British Columbia (Canada)] [and others

1994-12-31

266

False Negative (99m)Tc-Hydroxymethane Diphosphonate Three-phase Bone Scintigraphy and (99m)Tc-besilesomab Scan in Detecting Tibia Osteomyelitis Concomitant with Necrotizing Fasciitis.  

PubMed

We described a case of 51-year-old female patient presented with a right calf necrotising fasciitis (NF) where osteomyelitis (OM) was suspected. (99m)Tc-hydroxymethane diphosphonate three-phase bone scintigraphy and (99m)Tc-besilosomab scan failed to demonstrate classical features of OM. The final diagnosis was only made by isolating Acinetobacter sp. in both intra-operative bone and tissue cultures from below-knee amputation. As conclusions, the detection of lower limb OM by (99m)Tc-besilosomab scan is not easy when there is concurrence overlying NF. The unusual three-phase bone scan finding of pericortical accumulation of tracer as an early sign of OM is highlighted in this case. PMID:25538491

Tan, Teik Hin; Lee, Boon Nang

2014-09-01

267

False Negative 99mTc-Hydroxymethane Diphosphonate Three-phase Bone Scintigraphy and 99mTc-besilesomab Scan in Detecting Tibia Osteomyelitis Concomitant with Necrotizing Fasciitis  

PubMed Central

We described a case of 51-year-old female patient presented with a right calf necrotising fasciitis (NF) where osteomyelitis (OM) was suspected. 99mTc-hydroxymethane diphosphonate three-phase bone scintigraphy and 99mTc-besilosomab scan failed to demonstrate classical features of OM. The final diagnosis was only made by isolating Acinetobacter sp. in both intra-operative bone and tissue cultures from below-knee amputation. As conclusions, the detection of lower limb OM by 99mTc-besilosomab scan is not easy when there is concurrence overlying NF. The unusual three-phase bone scan finding of pericortical accumulation of tracer as an early sign of OM is highlighted in this case.

Tan, Teik Hin; Lee, Boon Nang

2014-01-01

268

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

269

Thermoelectric Generators 1. Thermoelectric generator  

E-print Network

1 Thermoelectric Generators HoSung Lee 1. Thermoelectric generator 1.1 Basic Equations In 1821 effects are called the thermoelectric effects. The mechanisms of thermoelectricity were not understood. Cold Hot I - -- - - - - -- Figure 1 Electron concentration in a thermoelectric material. #12;2 A large

Lee, Ho Sung

270

Energy generator  

SciTech Connect

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

Krisko, P.

1989-08-01

271

The Unusual Magnetic Resonance Properties of Trigonal Prismatic Tc and Re Complexes  

Microsoft Academic Search

The electron paramagnetic resonance (EPR) spectra of the trigonal prismatic complexes Tc(abt)3, Tc(bdt)3, Re(abt)3 and Re(bdt)3 (abt, O-aminobenzenethiol; bdt, benzene-1,2-dithiol) in dilute frozen solution are interpreted in terms of an axially symmetric spin\\u000a Hamiltonian, with g values close to two, principal hyperfine couplings of |A\\u000a Tc| ~ 5–12 × 10?4 cm?1, nuclear quadrupole couplings of |P\\u000a Tc| ~ 0.3–0.35 × 10?4 cm?1 and the unusual values 5 × 10?4 cm?1 ~ |A\\u000a \\u000a zz\\u000a Re| P\\u000a Re| ~ |A\\u000a \\u000a xx

Simon C. Drew; John Baldas; John F. Boas

272

Ran/TC4: a small nuclear GTP-binding protein that regulates DNA synthesis  

PubMed Central

Ran/TC4, first identified as a well-conserved gene distantly related to H-RAS, encodes a protein which has recently been shown in yeast and mammalian systems to interact with RCC1, a protein whose function is required for the normal coupling of the completion of DNA synthesis and the initiation of mitosis. Here, we present data indicating that the nuclear localization of Ran/TC4 requires the presence of RCC1. Transient expression of a Ran/TC4 protein with mutations expected to perturb GTP hydrolysis disrupts host cell DNA synthesis. These results suggest that Ran/TC4 and RCC1 are components of a GTPase switch that monitors the progress of DNA synthesis and couples the completion of DNA synthesis to the onset of mitosis. PMID:8421051

1993-01-01

273

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

274

Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)  

NASA Astrophysics Data System (ADS)

99Technetium ( 99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life ( t1/2 = 2.13 × 10 5 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron, either in aqueous form (Fe 2+) or in mineral form [Fe(II)], has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) has not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Surface Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total structural Fe content of these clay minerals, after surface Fe-oxide removal, ranged from 0.7% to 30.4% by weight, and the structural Fe(III)/Fe(total) ratio ranged from 45% to 98%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with structural Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella putrefaciens CN32 cells as a mediator. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. In the S-I series, smectite (montmorillonite) was the most reducible (18% and 41% without and with AQDS, respectively) and illite the least (1% for both without and with AQDS). The extent and initial rate of bioreduction were positively correlated with the percent smectite in the S-I series (i.e., layer expandability). Fe(II) in the bioreduced clay minerals subsequently was used to reduce Tc(VII) to Tc(IV) in PIPES buffer. Similar to the trend of bioreduction, in the S-I series, reduced NAu-2 showed the highest reactivity toward Tc(VII), and reduced illite exhibited the least. The initial rate of Tc(VII) reduction, after normalization to clay and Fe(II) concentrations, was positively correlated with the percent smectite in the S-I series. Fe(II) in chlorite and palygorskite was also reactive toward Tc(VII) reduction. These data demonstrate that crystal chemical parameters (layer expandability, Fe and Fe(II) contents, and surface area, etc.) play important roles in controlling the extent and rate of bioreduction and the reactivity toward Tc(VII) reduction. Reduced Tc(IV) resides within clay mineral matrix, and this association could minimize any potential of reoxidation over long term.

Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.; Liu, Chongxuan; Edelmann, Richard E.

2011-09-01

275

Anisotropie van de energiekloof in hoge Tc supergeleiders Mark Golden Sanne de Jong  

E-print Network

Anisotropie van de energiekloof in hoge Tc supergeleiders Mark Golden Sanne de Jong mgolden-atsign-science.uva.nl sdejong-atsign-science.uva.nl In de groep `Quantum electron matter' van het Van der Waals-Zeeman instituut

276

DCC -1 semestre de 2012 TC021 Mecnica Geral I -1 Semestre  

E-print Network

Dalledone Machado Turma B Miguel Frederico Hilgenberg Neto Turma C Marcos Antonio Marino Turma D Marco André Estruturas de Madeira Turma A Miguel Frederico Hilgenberg Neto TC058 Pontes e Estruturas Especiais Turma

Paraná, Universidade Federal do

277

The Ideal Liquid Discovered by RHIC, Infrared Slavery Above and Hadronic Freedom Below $T_c$  

E-print Network

We construct the nature of the matter found in RHIC when its temperature has dropped down close to, and below, $T_c$. Just above $T_c$ it is composed of extremely strongly bound quark-antiquark pairs forming chirally restored mesons of the quantum numbers of the $\\pi, S, \\rho$ and $a_1$ with very small size and zero energy and just below $T_c$, it is composed of mesons of the same quantum numbers with zero mass. We invoke infrared slavery for the former and the vector manifestation (VM) of hidden local symmetry for the latter. As the temperature drops below $T_c$, the strongly bound quark-antiquark pairs are ejected into what is basically a region of "hadronic freedom" in which the interactions are zero. Experimental evidences for this are seen in the STAR data.

Gerald E. Brown; Chang-Hwan Lee; Mannque Rho

2005-07-05

278

Reduction of pertechnetate [Tc(VII)] by aqueous Fe(II) and the nature of solid phase redox products  

NASA Astrophysics Data System (ADS)

The subsurface behaviour of 99Tc, a contaminant resulting from nuclear fuels reprocessing, is dependent on its valence (e.g., IV or VII). Abiotic reduction of soluble Tc(VII) by Fe(II) (aq) in pH 6-8 solutions was investigated under strictly anoxic conditions using an oxygen trap (<7.5 × 10 -9 atm O 2). The reduction kinetics were strongly pH dependent. Complete and rapid reduction of Tc(VII) to a precipitated Fe/Tc(IV) form was observed when 11 ?mol/L of Tc(VII) was reacted with 0.4 mmol/L Fe(II) at pH 7.0 and 8.0, while no significant reduction was observed over 1 month at pH 6.0. Experiments conducted at pH 7.0 with Fe(II) (aq) = 0.05-0.8 mmol/L further revealed that Tc(VII) reduction was a combination of homogeneous and heterogeneous reaction. Heterogeneous reduction predominated after approximately 0.01 mmol/L of Fe(II) was oxidized. The heterogeneous reaction was more rapid, and was catalyzed by Fe(II) that adsorbed to the Fe/Tc(IV) redox product. Wet chemical and Fe-X-ray absorption near edge spectroscopy measurements (XANES) showed that Fe(II) and Fe(III) were present in the Fe/Tc(IV) redox products after reaction termination. 57Fe-Mössbauer, extended X-ray adsorption fine structure (EXAFS), and transmission electron microscopy (TEM) measurements revealed that the Fe/Tc(IV) solid phase was poorly ordered and dominated by Fe(II)-containing ferrihydrite with minor magnetite. Tc(IV) exhibited homogeneous spatial distribution within the precipitates. According to Tc-EXAFS measurements and structural modeling, its molecular environment was consistent with an octahedral Tc(IV) dimer bound in bidentate edge-sharing mode to octahedral Fe(III) associated with surface or vacancy sites in ferrihydrite. The precipitate maintained Tc(IV) aq concentrations that were slightly below those in equilibrium with amorphous Tc(IV)O 2· nH 2O (s). The oxidation rate of sorbed Tc(IV) in the Fe/Tc precipitate was considerably slower than Tc(IV)O 2· nH 2O (s) as a result of its intraparticle/intragrain residence. Precipitates of this nature may form in anoxic sediments or groundwaters, and the intraparticle residence of sorbed/precipitated Tc(IV) may limit 99Tc remobilization upon the return of oxidizing conditions.

Zachara, John M.; Heald, Steve M.; Jeon, Byong-Hun; Kukkadapu, Ravi K.; Liu, Chongxuan; McKinley, James P.; Dohnalkova, Alice C.; Moore, Dean A.

2007-05-01

279

Three-Component Spectroelectrochemical Sensor Module for the Detection of Pertechnetate (TcO4-)  

SciTech Connect

This review looks at the advancements in the development of a sensor for technetium (Tc) that is applicable to characterizing and monitoring the vadose zone and associated subsurface water. Subsurface contamination by Tc is of particular concern for two reasons: the extremely long lifetime of its most common isotope 99Tc (half-life = 2 x 105 years) and the fast migration in soils of pertechnetate (TcO4–) which is considered to be the dominant 99Tc species in ground water. TcO4– does not have a characteristic spectral signature which prevents its rapid, sensitive, and economic in-situ detection. To address this problem, a novel spectroelectrochemical sensor has been designed that combines three modes of selectivity (electrochemistry, spectroscopy, and selective partitioning) into a single sensor to substantially improve specificity which is critical in the specific detection of an analyte in the presence of potential interfering species. The sensor consists of a basic spectroelectrochemical configuration: a waveguide with an optically transparent electrode (OTE) that is coated with a thin chemically-selective film that preconcnetrates the analyte. The key to adapting this generic sensor to detect TcO4– and Tc complexes lies in the development of chemically-selective films that preconcentrate the analyte and, when necessary, chemically convert it into a complex with electrochemical and spectroscopic properties appropriate for sensing. This review focuses on the general concept of the sensor and the rationale for the selection of the specific components of choice, the development and characterization of the sensor for the different detection modules, the synthesis and characterization of complexes relevant in the detection of technetium, and the progress in the utilization of the sensor module for the effective detection of these complexes.

Chatterjee, Sayandev; Bryan, Samuel A.; Seliskar, Carl J.; Heineman, William R.

2013-07-01

280

Nuclear Quadrupole Resonance of Cu in High-Tc Bi-Pb-Sr-Ca-Cu-O  

Microsoft Academic Search

Nuclear quadrupole resonance (NQR) signals of Cu have been discovered in the high-Tc superconducting oxide Bi-Pb-Sr-Ca-Cu-O with Tc{=}109 K. It has been observed that there are two Cu sites with a different quadrupole coupling. The temperature dependence of the nuclear relaxation rate, 1\\/T1, was similar to that of the CuO2 plane in YBa2Cu3O7. It is found that the 1\\/T1 for

Kenji Fujiwara; Yoshio Kitaoka; Kunisuke Asayama; Hiroyuki Sasakura; Sinnosuke Minamigawa; Kiyotaka Nakahigashi; Shigemitsu Nakanishi; Mineo Kogachi; Nobuo Fukuoka; Akira Yanase

1989-01-01

281

Formation of thin film Tl-based high-Tc? superconducting oxides from amorphous alloy precursors  

E-print Network

FORMATION OF THIN FILM Tl-BASED HIGH-Tc SUPERCONDUCTING OXIDES FROM AMORPHOUS ALLOY PRECURSORS A Thesis JOHN CHARLES WILLIAMS Submitted to the Once of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1991 Major Subject: Physics FORMATION OF THIN FILM Tl BASED HIGH Tc SUPERCONDUCTING OXIDES FROM AMORPHOUS ALLOY PRECURSORS A Thesis JOHN CHARLES WILLIAMS Approved as to style and content by: Donald G. Naugle...

Williams, John Charles

2012-06-07

282

Pseudogap in High Tc Superconductor YBa_2Cu_3O7 (YBCO)  

Microsoft Academic Search

One of the peculiar features of high Tc oxide superconductors, a normal state gap (or pseudo-gap), remains a subject of controversy. Experimental results indicate that the superconducting energy gap function survives even above the transition temperature T_c. In this work , we used a first-principle LCAO method to compute the electronic structure of YBCO. The electron-phonon coupling matrix elements are

G. L. Zhao; D. Bagayoko

1998-01-01

283

Influence of strain and composition on Tc in FeSe1-xTex films  

NASA Astrophysics Data System (ADS)

FeSe1-xTex films with wide ranging strain and composition were deposited using pulsed laser deposition, and lattice parameters and critical temperature (Tc) were evaluated in the films to understand influence of strain and composition on Tc of FeSe1-xTex films. c was larger than that in bulk and a was smaller than the bulk value due to strain (substrate effect), where c and a are c-axis length (perpendicular to film surface) and a-axis length (parallel to film surface) in the c-axis oriented FeSe1-xTex films. Depending on c value, two kinds of regions were observed regarding relationship between a and Tc. In the case of small c (c < 5.9 Å: small Te content), lattice parameter dependence of Tc in the films was different from that in bulk with different Te content, and Tc strongly increased with decrease in a. On the other hand, in the case of large c (c > 5.9 Å: large Te content), lattice parameter dependence of Tc in the films was similar to that in bulk with different Te content, and in-plane film strain did not vary Tc. In first principle band calculation, ab-plane bi-axial strain varied the Fermi surface in FeSe (c < 5.9 Å), but such strain-induced variation of Fermi surface was smaller in FeSe0.5Te0.5 (c > 5.9 Å), which is consistent with the experimental results. The present results suggest that much higher Tc than the bulk values is obtained by decreasing a (compressive ab-plane strain) with keeping c < 5.9 Å (small Te content) using hydrostatic pressure and/or film strain.

Horide, Tomoya; Sanyoushi, Masahiro; Ichinose, Ataru; Matsumoto, Kaname

2014-12-01

284

The clinical utility of 99 m Tc-HMPAO SPECT in Fahr’s disease  

Microsoft Academic Search

Fahr’s disease is a rare neurodegenerative syndrome, characterized by massive symmetrical intracerebral calcifications of\\u000a the basal ganglia, dentate nuclei of the cerebellum, and the adjacent parenchyma. Computerized tomography (CT) is considerably\\u000a more sensitive to detect these intracranial calcifications than other imaging modalities. The clinical, CT scan, and 99mTc-D,L-hexamethylpropylene amine oxime (99mTc-HMPAO) brain perfusion single-photon emission computerized tomography (SPECT) findings in

Tunc Ones; Fuat Dede; Dilek Gunal; Gazanfer Ekinci; Hatice Memis; Tanju Y. Erdil; Sabahat Inanir; Halil T. Turoglu

2008-01-01

285

Chemical Manipulation of High-TC Ferromagnetism in ZnO Diluted Magnetic Semiconductors  

Microsoft Academic Search

We report the use of targeted p- and n-type chemical perturbations to manipulate high-TC ferromagnetism in Mn2+:ZnO and Co2+:ZnO in predictable and reproducible ways. We demonstrate a clear correlation between nitrogen and high-TC ferromagnetism for Mn2+:ZnO and an inverse correlation for Co2+:ZnO, both as predicted by recent theoretical models. These chemical perturbations reveal rich possibilities for exerting external control over

Kevin R. Kittilstved; Nick S. Norberg; Daniel R. Gamelin

2005-01-01

286

Detection of gastritis by /sup 99m/Tc-labeled red-blood-cell scintigraphy  

SciTech Connect

Gastritis is a common condition, with a variety of causes, that is diagnosed most often by barium upper gastrointestinal tract series or endoscopy. The authors report a case in which gastritis without active bleeding was apparent in scintiscans obtained during the evaluation of GI bleeding using /sup 99m/Tc-labeled red blood cells (TcRBC). The scintigraphic findings that suggest gastritis are described.

Wilton, G.P.; Wahl, R.L.; Juni, J.E.; Froelich, J.W.

1984-10-01

287

Deconvolution analysis of 99m Tc-methylene diphosphonate kinetics in metabolic bone disease  

Microsoft Academic Search

The kinetics of 99mTc-methylene diphosphonate (MDP) and 47Ca were studied in three patients with osteoporosis, three patients with hyperparathyroidism, and two patients with osteomalacia. The activities of 99mTc-MDP were recorded in the lumbar spine, paravertebral soft tissues, and in venous blood samples for 1 h after injection. The results were submitted to deconvolution analysis to determine regional bone accumulation rates.

J. Knop; E. Kröger; P. Stritzke; C. Schneider; H.-P. Kruse

1981-01-01

288

Extraction of Am, Eu, Tc, and Pd from nitric acid solutions with phosphorylated calixarenes  

Microsoft Academic Search

Extraction of Am, Eu, Pd, and Tc from 0.1–3.0 M HNO3 with solutions of phosphorylated calix[n]arenes in m-nitrobenzotrifluoride (NBTF) was studied. The ring size and position of phosphoryl groups (in the upper or lower rim) affect\\u000a the extraction of Am and Eu significantly and that of Tc and Pd only slightly. Calix[4]arenes phosphorylated at the upper\\u000a rim extract Am and

I. V. Smirnov; M. D. Karavan; T. I. Efremova; V. A. Babain; S. I. Miroshnichenko; S. A. Cherenok; V. I. Kal’chenko

2007-01-01

289

Preparation and evaluation of a new 99m Tc labeled bombesin derivative for tumor imaging  

Microsoft Academic Search

A variety of human tumors like prostate and breast cancer express bombesin receptors. Due to this a new bombesin analogue\\u000a was labeled with 99mTc via HYNIC and tricine as a coligand and investigated further. Peptide was synthesized on a solid phase using Fmoc strategy.\\u000a Labeling with 99mTc was performed at 100 °C for 10 min and radiochemical analysis involved ITLC and HPLC

N. Sadeghzadeh; M. Gandomkar; R. Najafi; M. Shafiei; S. E. Sadat Ebrahimi; A. Shafiee; B. Larijani

2010-01-01

290

Nitriles form mixed-coligand complexes with 99mTc-HYNIC-Peptide  

Microsoft Academic Search

Using a 12-amino acid peptide conjugated with HYNIC as a model, we investigated nitriles as possible coligands for labeling with 99mTc. After the preparation of the 99mTc labeled HYNIC-peptide using tricine as coligand, the addition of acetonitile was found by reverse phase HPLC to block further coligand exchange with ethylenediamine diacetic acid (EDDA) at room temperature. The addition of this

Guozheng Liu; Charles Wescott; Aaron Sato; Yi Wang; Ning Liu; Yu-Min Zhang; Mary Rusckowski; Donald J. Hnatowich

2002-01-01

291

Asialoglycoprotein-receptor-targeted hepatocyte imaging using 99mTc galactosylated chitosan  

Microsoft Academic Search

This study investigated the usefulness of 99mTc hydrazinonicotinamide-galactosylated chitosan (HGC) in hepatocyte imaging. HGC was obtained by coupling the galactose moiety of both lactobionic acid and succinimidyl 6-hydrazinonicotinate hydrochloride (succinimidyl HYNIC). The coupled product was then radiolabeled with 99mTc using stannous chloride and tricine as reducing agent and coligand, respectively. Labeling efficiency was >90% both in room temperature and in

Eun-Mi Kim; Hwan-Jeong Jeong; Se-Lim Kim; Myung-Hee Sohn; Jae-Woon Nah; Hee-Seung Bom; In-Kyu Park; Chong-Su Cho

2006-01-01

292

Comparative Analysis of the Recently Discovered hAT Transposon TcBuster in Human Cells  

PubMed Central

Background Transposons are useful tools for creating transgenic organisms, insertional mutagenesis, and genome engineering. TcBuster, a novel hAT-family transposon system derived from the red flour beetle Tribolium castaneum, was shown to be highly active in previous studies in insect embryoes. Methodology/Principal Findings We tested TcBuster for its activity in human embryonic kidney 293 (HEK-293) cells. Excision footprints obtained from HEK-293 cells contained small insertions and deletions consistent with a hAT-type repair mechanism of hairpin formation and non-homologous end-joining. Genome-wide analysis of 23,417 piggyBac, 30,303 Sleeping Beauty, and 27,985 TcBuster integrations in HEK-293 cells revealed a uniquely different integration pattern when compared to other transposon systems with regards to genomic elements. TcBuster experimental conditions were optimized to assay TcBuster activity in HEK-293 cells by colony assay selection for a neomycin-containing transposon. Increasing transposon plasmid increased the number of colonies, whereas gene transfer activity dependent on codon-optimized transposase plasmid peaked at 100 ng with decreased colonies at the highest doses of transposase DNA. Expression of the related human proteins Buster1, Buster3, and SCAND3 in HEK-293 cells did not result in genomic integration of the TcBuster transposon. TcBuster, Tol2, and piggyBac were compared directly at different ratios of transposon to transposase and found to be approximately comparable while having their own ratio preferences. Conclusions/Significance TcBuster was found to be highly active in mammalian HEK-293 cells and represents a promising tool for mammalian genome engineering. PMID:23166581

Woodard, Lauren E.; Li, Xianghong; Malani, Nirav; Kaja, Aparna; Hice, Robert H.; Atkinson, Peter W.; Bushman, Frederic D.; Craig, Nancy L.; Wilson, Matthew H.

2012-01-01

293

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

294

Tc99m-MIBI scintigraphy for recurrent hyperparathyroidism after total parathyroidectomy with autograft  

Microsoft Academic Search

The aim of this study is to assess the sensitivity of Tc-99m-MIBI for the pre-operative localization of hyperfunctioning parathyroid\\u000a glands in patients with persistent or recurrent hyperparathyroidism (HPT) after total parathyroidectomy (PTX) with autograft.Patients and Methods: Tc-99m-MIBI scintigraphy was performed on 7 patients (3 men and 4 women; aged 32 to 62) on hemodialysis with persistent\\u000a or recurrent HPT after

Kazuo Itoh; Reiki Ishizuka

2003-01-01

295

Neutron induced reaction cross sections for the radioactive target nucleus 99Tc  

NASA Astrophysics Data System (ADS)

We present the first measured and interpreted excitation functions for three nuclear reactions on the radioactive target nucleus 99Tc over the energy range from threshold to 20.6 MeV. Excitation functions for the 99Tc( n,n?) 99mTc, 99Tc( n,p) 99Mo, and 99Tc( n,?) 96Nb reactions were measured using the activation method. High-resolution ?-ray spectroscopy was used requiring special attention to suppress Bremsstrahlung. The irradiated samples consisted of pressed pellets of metallic 99Tc in Al-capsules. Quasi mono-energetic neutrons were produced via the 3H( p,n) 3He, 2H( d,n) 3He, and 3H( d,n) 4He reactions. The neutron fluence was monitored via the well-known 115In( n,n) 115mIn, 27Al( n,?) 24Na, 27Al( n,p) 27Mg, 56Fe( n,p) 56Mn, and 93Nb( n,2n) 92mNb standard reactions. Statistical model calculations incorporating precompound effects were performed for all the measured reaction channels using two different codes, namely TALYS and STAPRE. Good agreement was obtained for the reactions in which a charged particle was emitted and for the excitation of the isomer in inelastic scattering, above 5 MeV.

Reimer, P.; Koning, A. J.; Plompen, A. J. M.; Qaim, S. M.; Sudár, S.

2009-01-01

296

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

297

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. PMID:24894734

2014-01-01

298

Dopamine Transporter Imaging Using 99mTc-TRODAT-1 SPECT in Parkinson’s Disease  

PubMed Central

Background Although the decrease in striatal dopamine transporter (DAT) density has been described in North American, European, and Asian Parkinson’s disease (PD) patients, studies on this issue are required in the rest of the world. This study examined the diagnostic utility of DAT imaging in Brazilian PD patients. Material/Methods Twenty PD patients (13 males, 7 females, median age: 62 years, median age at disease onset: 56 years, median disease duration: 5 years, and median UPDRS-III score: 29) and 9 age- and sex-matched healthy subjects underwent single-photon emission computerized tomography (SPECT) using 99mTc-TRODAT-1. Results PD patients showed a significant decrease in the striatum, caudate nucleus, and putamen DAT densities compared with data from healthy subjects. Striatal 99mTc-TRODAT-1 bindings had the highest diagnostic accuracy compared to those estimates from caudate nucleus and putamen. For the diagnosis of PD, a striatal 99mTc-TRODAT-1 binding cut-off value of 0.90 was associated with a sensitivity of 100% and a specificity of 89%. There was no significant difference between striatal 99mTc-TRODAT-1 binding values provided by different readers, contrary to 99mTc-TRODAT-1 binding estimates in the caudate nucleus. Conclusions Striatal DAT imaging using 99mTc-TRODAT-1 can be considered a marker for differentiating PD patients from healthy individuals, with a good interobserver reproducibility. PMID:25109468

Bor-Seng-Shu, Edson; Felicio, Andre C.; Braga-Neto, Pedro; Batista, Ilza Rosa; Paiva, Wellingson Silva; de Andrade, Daniel Ciampi; Teixeira, Manoel Jacobsen; de Andrade, Luiz Augusto Franco; Barsottini, Orlando Graziani Povoas; Shih, Ming Chi; Bressan, Rodrigo A.; Ferraz, Henrique Ballalai

2014-01-01

299

Click chemistry for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin.  

PubMed

(99m)Tc-HYNIC labeled Lys(3)-bombesin has shown specific binding to gastrin-releasing peptide receptors (GRP-r) over-expressed in cancer cells. Click chemistry offers an innovative functionalization strategy for biomolecules such as bombesin. The aim of this research was to apply a click chemistry approach for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin and to compare the in vitro MCF7 breast cancer cell uptake and biodistribution profile in mice with that of (99m)Tc-EDDA/HYNIC-Lys(3)-bombesin. The results suggest a higher lipophilicity for (99m)Tc(CO)(3)-triazole-Lys(3)-bombesin which explains its higher in vivo hepatobiliary elimination. Pancreas-to-blood ratio for (99m)Tc(CO)(3)-triazole-Lys(3)-bombesin was 4.46 at 3 h and both bombesin radiopharmaceuticals showed specific recognition for GRP receptors in MCF7 cancer cells. Click chemistry is a reliable approach for [(99m)Tc(CO)(3)] labeling of Lys(3)-bombesin. PMID:20580238

Ferro-Flores, G; Rivero, I A; Santos-Cuevas, C L; Sarmiento, J I; Arteaga de Murphy, C; Ocampo-García, B E; García-Becerra, R; Ordaz-Rosado, D

2010-12-01

300

Animal studies of 99mTc-i-PIDP: a new bone imaging agent.  

PubMed

This study was to investigate the preparation and biodistribution of (99m)Tc-labeled novel zoledronic acid derivative 1-hydroxy-2-(2-isopropyl-1H-imidazole-1-yl) ethylidene-1,1-bisphosphonic ((99m)Tc-i-PIDP) as a potential bone imaging agent. Satisfactory labeling results (radiochemical purity over 95%) were obtained when the amount of i-PIDP, Na(99m)TcO(4), and SnCl(2)·2H(2)O, were 5 mg, 37 MBq, and 100 ?g, respectively, the pH value was between 4.0 and 6.0, and the labeling reaction continued for 30 min. The labeled complex was stable at least up to 6h in vitro. The biodistribution and pharmacokinetics studies in mice and single photon emission computed tomography (SPECT) bone scan in rabbit of (99m)Tc-i-PIDP were systematically studied. The results showed that the bone uptake is up to 9.63%ID/g at 60 min after injection of (99m)Tc-i-PIDP. The pharmacokinetic studies indicate that the data can be fitted to a two-compartment model with the equation of C=5.80e(-0.20t)+2.66e(-0.01t). A plain bone image was obtained at 1 h. All of the results suggested that (99m)Tc-i-PIDP is worthy of future investigation as a novel bone imaging agent. PMID:21507669

Wang, Yan; Luo, Shineng; Lin, Jianguo; Qiu, Ling; Cheng, Wen; Zhai, Haozhen; Nan, Beibei; Ye, Wanzhong; Xia, Yongmei

2011-09-01

301

Performing 18F-FDG PET studies following injections of 99mTc-sestamibi  

NASA Astrophysics Data System (ADS)

When SPECT studies are followed by PET studies on the same day, substantial 99mTc activity may be present in patients during the PET scans. Degraded PET camera performance results unless the low-energy gamma rays are absorbed by lead shields. Spatial resolution, camera count rates, energy spectra, image contrast and noise, and image quality have been measured for phantoms with varying levels of 99mTc activity, and both with and without thin lead shields placed in front of the detectors. In addition examples of the results of twelve 18F-FDG PET cardiac studies performed within 6 h of 99mTc-sestamibi injections are reported. The presence of 99mTc (140 keV gamma rays) causes light pile-up with 511 keV photons resulting in distorted energy spectra, degraded spatial resolution, increased Compton background and reduced count-rate capability. These effects are avoided using thin lead shields. Studies performed with 99mTc activity in patients but using lead shields are of comparable quality to studies performed without 99mTc or shields. Thin lead shields effectively filter low-energy gamma rays during PET studies leading to improved count-rate capability, contrast and image quality.

Smith, R. J.; Karp, J. S.

1999-06-01

302

Correlation of 99mTc-sestamibi uptake with blood-pool and osseous phase 99mTc-MDP uptake in malignant bone and soft-tissue tumours.  

PubMed

Technetium-99m-sestamibi (99mTc-MIBI) imaging is a well-established modality in oncologic investigations. The current study aimed to investigate whether any relationship could be found between 99mTc-MIBI uptake and local perfusion in malignant bone and soft-tissue tumours. It also aimed to compare 99mTc-MIBI images with those of technetium-99m-methylene diphosphonate (99mTc-MDP) bone scintigraphy with regard to the activity distribution pattern, intensity and lesion extension. The study group included 24 patients with various bone and soft-tissue tumours. Three-phase bone scintigraphy and 99mTc-MIBI studies were performed within the same week before any surgical and therapeutic intervention. Images were evaluated visually and quantitatively using regions of interest (ROIs) over the lesion and adjacent normal tissue. The 99mTc-MIBI study was positive with varying degrees of uptake (range, 1.4-5.3). The mean 99mTc-MIBI uptake and 99mTc-MDP blood-pool and osseous phase activity ratios were 2.5 +/- 0.5, 2.8 +/- 1.0 and 5.5 +/- 4.0, respectively. The correlation between the 99mTc-MIBI uptake and blood-pool ratios was 0.70 (P<0.05). While activity distribution patterns were in agreement in 99mTc-MIBI and blood-pool images in the majority of cases, 99mTc-MIBI better delineated tumour viability and extension in five cases. In conclusion, 99mTc-MIBI accumulation shows a reasonable correlation with blood-pool uptake assuming the presence of multifactorial mechanisms in addition to local hyperaemia. Better delineation of tumour outlines and cellular activity seems to be an advantage of 99mTc-MIBI scintigraphy which may be helpful in the evaluation of musculoskeletal tumours. PMID:11403180

Ozcan, Z; Burak, Z; Erinç, R; Dirlik, A; Ba?demir, G; Sabah, D; Ozkiliç, H

2001-06-01

303

Anelastic spectroscopy studies of high-Tc superconductors  

NASA Astrophysics Data System (ADS)

YBCO, LSCO and Ru-1212 have been extensively studied by measuring the complex dynamic Young's modulus at 0.5-20 kHz between 1 and 900 K. The elastic energy loss is peaked at the temperatures where the relaxation rate of any microscopic process coupled to strain equals the measuring frequency. The reliability of the anelastic experiments and of the assignments to various microscopic mechanisms is also discussed. In LSCO, the layers of octahedra present solitonic tilt waves and fast local motion. The latter is driven by atomic tunneling and is enormously enhanced and accelerated by doping, demonstrating direct coupling between tilt modes and hole excitations. The dynamics of the hole stripes has been probed when they act as walls between domains of antiferromagnetically correlated spins (cluster spin glass) at LHe temperature, and at higher temperature, when they overcome by thermal activation the pinning barriers provided by Sr dopants. In YBCO various diffusion and ordering processes of the O atoms in the CuOx planes are identified, involving: i) Cu-O chains in the orthorhombic O-I phase (x~1); ii) sparser chains fragments at lower O content; iii) isolated O atoms. The hopping barriers are ~1 eV for the first two types of jumps and 0.11 eV for the latter. It is discussed how such widely different barriers are possible and how the extraordinarily high mobility of isolated O atoms is compatible with slow O ordering. In addition, relaxation processes have been attributed to hopping of O between off-center positions within the Cu-O chains and to bipolarons on orbitals that do not contribute to superconductivity. The O mobility in the RuO2-d planes of Ru-1212 is explained in terms of hopping of O vacancies whose elastic quadrupoles are weakly interacting and start becoming parallel to each other below TC ~ 470 K.

Cordero, F.

2006-01-01

304

Phosphine-containing HYNIC derivatives as potential bifunctional chelators for (99m)Tc-labeling of small biomolecules.  

PubMed

Two prototype phosphine-containing HYNIC chelators, HYNIC-Kp-DPPB and HYNIC-Ko-DPPB (HYNIC = 6-hydrazinonicotinamide; K = lysine; and DPPB = diphenylphosphine-benzoic acid), have been synthesized and characterized by NMR ((1)H, (13)C, and (31)P) and LC-MS. Macrocyclic (99m)Tc complexes, [(99m)Tc(HYNIC-Ko-TPPB)(tricine)] and [(99m)Tc(HYNIC-Kp-DPPB)(tricine)], were prepared by reacting the phosphine-containing HYNIC chelator with (99m)TcO(4)(-) in the presence of excess tricine and stannous chloride. Results from this study clearly demonstrated that both HYNIC-Kp-DPPB and HYNIC-Ko-DPPB are able to form highly stable macrocyclic (99m)Tc complexes, [(99m)Tc(HYNIC-Ko-TPPB)(tricine)] and [(99m)Tc(HYNIC-Kp-DPPB)(tricine)], when tricine is used as the coligand. Radio-HPLC data suggest that the complex [(99m)Tc(HYNIC-Kp-DPPB)(tricine)] exists as only one detectable isomer in solution while the complex [(99m)Tc(HYNIC-Ko-DPPB)(tricine)] has three isomers. It was also found that three isomers of [(99m)Tc(HYNIC-Ko-DPPB)(tricine)] interconvert at elevated temperatures, suggesting that the presence of these isomers might be due conformational changes in the macrocyclic Tc chelate. The LC-MS data for both macrocyclic (99m)Tc complexes are completely consistent with the proposed composition. The phosphine-containing HYNIC chelators described in this study may have the potential as bifunctional chelators for (99m)Tc labeling of small biomolecules. PMID:12862424

Purohit, Ajay; Liu, Shuang; Casebier, Dave; Edwards, D Scott

2003-01-01

305

Manipulating attentional load in sequence learning through random number generation  

PubMed Central

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

306

Quantitative analysis by digital computer of Tc-99m N-pyridoxyl-5-methyltryptophan (Tc-99m PMT) hepatogram in diffuse parenchymal liver diseases  

SciTech Connect

Tc-99m N-pyridoxyl-5 methyltryptophan (Tc-99m PMT) hepatograms were analyzed to provide information about the liver and bile duct. Calculations were based on a 4 compartmental model and included corrections for blood, tissue, liver and bile backgrounds. The time-activity curves for Tc-99m PMT in the cardiac region were described as the sum of 2 exponential functions, while curves for the hepatic region were described as the sum of 3 exponential components. The measured hepatograms were compared with simulated hepatograms and good agreement between the two curves showed that the compartmental model adequately described the blood and bile activities in vivo. Hepatic excretion rates were 0.179 +- 0.028 in 3 normal subjects. 0.102 +- 0.012 in 4 patients of chronic hepatitis and 0.116 +- 0.061 in 6 patients of liver cirrhosis. In the cases of diffuse parenchyal liver diseases, there were lower rate constants for the excretion from the liver to the bile ducts than in normals and the relative distribution values also larger than normal. Prior to the development of this compartmental model, no useful kinetic model had been found which could satisfactorily explain the time-activity curves. Experience in human studies proves this method to be accurate in determining the rate constants for hepatobiliary transport of Tc-99m PMT.

Narabayashi, I.; Ishido, N.; Sugimura, K.; Nabeshima, K.; Sugimura, C.; Matsuo, M.; Kimura, S.; Kajita, A.

1984-01-01

307

Immunomodulation by Trypanosoma cruzi: Toward Understanding the Association of Dendritic Cells with Infecting TcI and TcII Populations  

PubMed Central

Dendritic cells (DCs) are major immune components, and depending on how these cells are modulated, the protective host immune response changes drastically. Trypanosoma cruzi is a parasite with high genetic variability and modulates DCs by interfering with their capacity for antigen recognition, migration, and maturation. Despite recent efforts, the association between DCs and T. cruzi I (TcI) and TcII populations is unknown. Herein, it was demonstrated that AQ1.7 and MUTUM TcI strains present low rates of invasion of bone marrow-derived DCs, whereas the 1849 and 2369 TcII strains present higher rates. Whereas the four strains similarly induced the expression of PD-L1, the production and expression of IL-10 and TLR-2, respectively, in DCs were differentially increased. The production of TNF-?, IL-12, IL-6, and CCL2 and the expression of CD40, CD80, MHC-II, CCR5, and CCR7 changed depending on the strain. The 2369 strain yielded the most remarkable results because greater invasion correlated with an increase in the levels of anti-inflammatory molecules IL-10 and PD-L1 but not with a change in the levels of TNF-?, MHC-II, or CD40 molecules. These results suggest that T. cruzi strains belonging to different populations have evolved specific evasion strategies that subvert DCs and consequently the host response. PMID:25371910

da Costa, Thiago Alvares; Silva, Marcos Vinicius; Mendes, Maria Tays; Carvalho-Costa, Tamires Marielem; Batista, Lara Rocha; Lages-Silva, Eliane; Rodrigues, Virmondes; Oliveira, Carlo Jose; Ramirez, Luis Eduardo

2014-01-01

308

Discrepant 99mTc-ECD images of CBF in patients with subacute cerebral infarction: a comparison of CBF, CMRO2 and 99mTc-HMPAO imaging.  

PubMed

Three patients with subacute ischemic cerebral infarction examined by SPECT with 99mTc-ECD and PET within the same day showed signs of luxury perfusion in the subacute phase, which is between 9 to 20 days after the onset. A 99mTc-HMPAO SPECT study was also performed within 2 days of the ECD-SPECT study. ECD-SPECT images of three patients displayed a focal decreased uptake in the infarcted lesions, while in infarcted foci, there was almost equivalent or increased CBF compared to normal and unaffected areas, decreased CMRO2, and high HMPAO uptake. The ECD-SPECT results were similar to those of CMRO2 rather than CBF, though the HMPAO-SPECT image was similar to that of CBF. In one patient, HMPAO images revealed hyperfixation of the tracer. In the chronic phase and in the acute phase before 5 days after the onset, there were no discrepancies among the ECD-SPECT, CBF, HMPAO-SPECT, and CMRO2 images. These observations indicated that 99mTc-ECD is a good indicator of damaged brain tissues in subacute ischemic infarction. They also suggested that 99mTc-ECD is a potential agent with which to evaluate cerebral tissue viability in some pathological states of cerebrovascular disease. The characteristics may be suitable for confirming the effects of thrombolytic therapy in acute ischemia, because these conditions often show signs of luxury perfusion when the therapy is successful. PMID:8534592

Shishido, F; Uemura, K; Inugami, A; Ogawa, T; Fujita, H; Shimosegawa, E; Nagata, K

1995-08-01

309

Platelet Binding and Biodistribution of 99mTc-rBitistatin in Animal Species and Humans  

PubMed Central

INTRODUCTION 99mTc-rBitistatin is a radioligand for the ?IIb?3 (GPIIb/IIIa) receptor on platelets and is being developed as a diagnostic radiopharmaceutical for in vivo imaging of acute thrombi and emboli. Prior to the first administration of 99mTc-rBitistatin to human subjects, its biodistribution and effects on platelets were evaluated in animals. This paper reports the findings of the animal studies in comparison with the initial findings in normal human subjects. METHODS 99mTc-rBitistatin was administered to mice, guinea pigs and dogs to assess time-dependent organ distribution, urinary excretion and blood disappearance rates. Blood samples were analyzed to determine radioligand binding to circulating platelets and the extent of plasma protein binding. The effect of 99mTc-rBitistatin on circulating platelet count was determined. These factors were also determined in normal human subjects who received 99mTc-rBitistatin as part of a Phase I clinical trial. RESULTS The main organs which accumulated 99mTc-rBitistatin were kidneys, liver and spleen in all animal species and humans. The main organs seen on human images were kidneys and spleen. Liver uptake was fainter, and soft tissue background was low. 99mTc-rBitistatin bound to circulating platelets in blood, with a higher percentage of binding to platelets in guinea pigs and dogs compared with humans. Plasma protein binding was low and of little consequence in view of the platelet binding. The main route of excretion was through the urine. 99mTc-rBitistatin did not affect platelet counts in humans or dogs. CONCLUSIONS 99mTc-rBitistatin when administered at low doses for imaging has no adverse effects on platelets and has the qualitative biodistribution predicted by animal studies. 99mTc-rBitistatin was found to bind to circulating platelets in humans, suggesting that it will be able to bind to activated platelets in vivo in patients with acute thrombi. PMID:17921036

Knight, Linda C.; Romano, Jan E.; Bright, Lewis T.; Agelan, Alexis; Kantor, Steven; Maurer, Alan H.

2007-01-01

310

Hydrogen Generator  

NASA Technical Reports Server (NTRS)

Another spinoff from spacecraft fuel cell technology is the portable hydrogen generator shown. Developed by General Electric Company, it is an aid to safer operation of systems that use hydrogen-for example, gas chromatographs, used in laboratory analysis of gases. or flame ionization detectors used as $ollution monitors. The generator eliminates the need for high-pressure hydrogen storage bottles, which can be a safety hazard, in laboratories, hospitals and industrial plants. The unit supplies high-purity hydrogen by means of an electrochemical process which separates the hydrogen and oxygen in distilled water. The oxygen is vented away and the hydrogen gas is stored within the unit for use as needed. GE's Aircraft Equipment Division is producing about 1,000 of the generators annually.

1978-01-01

311

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

312

Non-syndromic Hearing Impairment in a Hungarian Family with the m.7510T>C Mutation of Mitochondrial tRNA(Ser(UCN)) and Review of Published Cases.  

PubMed

The m.7510T>C mitochondrial DNA (mtDNA) mutation is a tRNA(Ser(UCN)) alteration leading to matrilineal isolated hearing impairment. The current paper reviews the available reports on the m.7510T>C mtDNA mutation, with special attention to phenotypic variations and haplogroup background. A Hungarian family, the fourth family reported in the literature, is presented, in which analysis of three generations with bilateral isolated hearing loss revealed the m.7510T>C tRNA(Ser(UCN)) mutation in homoplasmic form in the affected members. Haplogroup analysis verified an unnamed subgroup of mitochondrial haplogroup H. Previously reported Spanish and North American Caucasian families belong to different subgroups of haplogroup H. Analyzing our biobank of Hungarian patients with sensorineural hearing loss, we did not detect this mutation in any other patient, nor was it found in Caucasian haplogroup H control samples. Comparing the cases reported so far, there is interfamilial variablity in the age of onset, accompanying symptoms, and haplogroup background. Our case adds further genetic evidence for the pathogenicity of the m.7510T>C mutation and underlines the need to include full mtDNA sequencing in the screening for unexplained hearing loss. PMID:23430555

Komlósi, Katalin; Maász, Anita; Kisfali, Péter; Hadzsiev, Kinga; Bene, Judit; Melegh, Béla I; Melegh, Béla; Ablonczy, Mária; Németh, Krisztina; Fekete, György

2013-01-01

313

Experimental partitioning of Tc, Mo, Ru, and Re between solid and liquid during crystallization in Fe-Ni-S 1 1 Associate editor: B. Mysen  

Microsoft Academic Search

Technetium isotopes 97Tc, 98Tc and 99Tc decay to 97Mo, 98Ru and 99Ru, with half-lives of 2.6 My, 4.1 My, and 0.21 My respectively. If there were early solar system processes that resulted in significant fractionation of Tc from the daughter elements, decay of extant Tc could have led to the creation of Mo and Ru isotopic heterogeneities. To assess the

C. Lazar; D. Walker; R. J. WALKER

2004-01-01

314

Sintesi di nuovi inibitori di Aurora chinasi a nucleo ossadiazolico.  

E-print Network

??Le Aurora chinasi rappresentano una famiglia di serina/treonina chinasi altamente conservata durante l’evoluzione. Esse sono regolatori chiave del ciclo cellulare e svolgono importanti funzioni durante… (more)

SGAMBELLURI, CLELIA

2012-01-01

315

Evaluating {sup 99m}Tc Auger electrons for targeted tumor radiotherapy by computational methods  

SciTech Connect

Purpose: Technetium-99m ({sup 99m}Tc) has been widely used as an imaging agent but only recently has been considered for therapeutic applications. This study aims to analyze the potential use of {sup 99m}Tc Auger electrons for targeted tumor radiotherapy by evaluating the DNA damage and its probability of correct repair and by studying the cellular kinetics, following {sup 99m}Tc Auger electron irradiation in comparison to iodine-131 ({sup 131}I) beta minus particles and astatine-211 ({sup 211}At) alpha particle irradiation. Methods: Computational models were used to estimate the yield of DNA damage (fast Monte Carlo damage algorithm), the probability of correct repair (Monte Carlo excision repair algorithm), and cell kinetic effects (virtual cell radiobiology algorithm) after irradiation with the selected particles. Results: The results obtained with the algorithms used suggested that {sup 99m}Tc CKMMX (all M-shell Coster-Kroning--CK--and super-CK transitions) electrons and Auger MXY (all M-shell Auger transitions) have a therapeutic potential comparable to high linear energy transfer {sup 211}At alpha particles and higher than {sup 131}I beta minus particles. All the other {sup 99m}Tc electrons had a therapeutic potential similar to {sup 131}I beta minus particles. Conclusions: {sup 99m}Tc CKMMX electrons and Auger MXY presented a higher probability to induce apoptosis than {sup 131}I beta minus particles and a probability similar to {sup 211}At alpha particles. Based on the results here, {sup 99m}Tc CKMMX electrons and Auger MXY are useful electrons for targeted tumor radiotherapy.

Tavares, Adriana Alexandre S.; Tavares, Joao Manuel R. S. [Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias s/n, 4200-465 Porto (Portugal)

2010-07-15

316

Enhanced inhibitory synaptic transmission in the spinal dorsal horn mediates antinociceptive effects of TC-2559  

PubMed Central

Background TC-2559 is a selective ?4?2 subtype of nicotinic acetylcholine receptor (nAChR) partial agonist and ?4?2 nAChR activation has been related to antinociception. The aim of this study is to investigate the analgesic effect of TC-2559 and its underlying spinal mechanisms. Results 1) In vivo bioavailability study: TC-2559 (3 mg/kg) had high absorption rate in rats with maximal total brain concentration reached over 4.6 ?M within first 15 min after administration and eliminated rapidly with brain half life of about 20 min after injection. 2) In vivo behavioral experiments: TC-2559 exerts dose dependent antinociceptive effects in both formalin test in mice and chronic constriction injury (CCI) model in rats by activation of ?4?2 nAChRs; 3) Whole-cell patch-clamp studies in the superficial dorsal horn neurons of the spinal cord slices: perfusion of TC-2559 (2 ?M) significantly increased the frequency, but not amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs). The enhancement of sIPSCs was blocked by pre-application of DH?E (2 ?M), a selective ?4?2 nicotinic receptor antagonist. Neither the frequency nor the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) of spinal dorsal horn neurons were affected by TC-2559. Conclusions Enhancement of inhibitory synaptic transmission in the spinal dorsal horn via activation of ?4?2 nAChRs may be one of the mechanisms of the antinociceptive effects of TC-2559 on pathological pain models. It provides further evidence to support the notion that selective ?4?2 subtype nAChR agonist may be developed as new analgesic drug for the treatment of neuropathic pain. PMID:21816108

2011-01-01

317

Generation Activities  

NSDL National Science Digital Library

This page presents activities related to generation of electricity from the Science & Engineering in the Lives of Students project. Activities include Electric Motor, Examine Transformers, Magnet and Coil, and Measuring Work. Each activity includes a detailed description, list of the materials needed, science concepts covered, and reflection questions.

2013-07-18

318

Lemma 3 Let C be any set, and suppose x C, then FC(x) TC(x). If C convex, then C -x FC(x), FC(x) is convex, and TC(x) = cl FC(x).  

E-print Network

Lemma 3 Let C be any set, and suppose ¯x C, then FC(¯x) TC(¯x). If C convex, then C - ¯x FC(¯x), FC(¯x) is convex, and TC(¯x) = cl FC(¯x). Proof The first statement follows from the definitions. FC(¯x) is convex by direct argument. For the final statement of the lemma, suppose that w TC(¯x

Ferris, Michael C.

319

Pressure effects on Tc in superconducting (Tl, Cs)1-xFe2-ySe2  

NASA Astrophysics Data System (ADS)

Hydrostatic-pressure (up to 0.96 GPa) dependence of Tc in a newly discovered Fe-based superconductor (Tl0.59Cs0.26)Fe1.9Se2 (Tc = 28 K, at ambient pressure) is reported. Static magnetization measurements under pressure indicate that the linear increase in Tc is initially rapid (dTc/dP ˜ 9.9 K . GPa-1) but slows down to dTc/dP ˜ 2.5 K . GPa-1 for P ? 0.18 GPa. The Tc of the superconducting phase is 32 K at pressure P = 0.96 GPa. The simple rigid band model or the Bardeen, Cooper, Schrieffer theory may not be sufficient to account for our observations, if one assumes that the lattice parameters would be linearly decreased with pressure.

Chen, S. C.; Syu, K. J.; Sung, H. H.; Lee, W. H.; Li, C. C.; Chen, Y. Y.

2013-04-01

320

Does decreased skeletal uptake of 99mTc-methylene bisphosphonate in irradiated bone indicate the absence of bone metastases?  

PubMed

Reduced uptake of 99mTc-methylene bisphosphonate (99mTc-MBP) was found in irradiated bone in all of 13 tumour-free patients who had undergone radiotherapy (30-40 Gy) due to seminoma 3-8 years prior to bone scintigraphy. Decreased uptake of 99mTc phosphate compounds can not per se be interpreted as a sign of absence of metastases or reduced tumour burden. PMID:8327735

Fosså, S D; Winderen, M

1993-04-01

321

Pharmacokinetics and Safety Profile of Ispronicline (TC1734), a New Brain Nicotinic Receptor Partial Agonist, in Young Healthy Male Volunteers  

Microsoft Academic Search

Recent research suggests that drugs activating nicotine acetylcholine receptors might be promising therapy in cognitive decline seen in the elderly, including Alzheimer’s disease. Ispronicline (TC-1734), a brain-selective &agr;4&bgr;2 nicotine acetylcholine receptor partial agonist, has shown memory-enhancing properties in rodents and a good tolerability profile. The safety and the full pharmacokinetic profile of TC-1734 and its N-desalkylated metabolite, TC-1784, were investigated

G. Dunbar; A. Demazières; A. Monreal; C. Cisterni; D. Metzger; R. Kuchibhatla; R. Luthringer

2006-01-01

322

99m Tc-Tetrofosmin brain SPECT in the assessment of meningiomas—correlation with histological grade and proliferation index  

Microsoft Academic Search

Meningiomas account for about 30% of all intracranial tumors. Evaluation of their proliferation rate is useful for assessing\\u000a their biological behavior. We evaluated prospectively whether 99mTc-Tetrofosmin (99mTc-TF) uptake in meningiomas correlates with cellular proliferative activity and with tumor grade. We prospectively studied\\u000a 18 meningioma cases. Brain single-photon emission computed tomography (SPECT) by 99mTc-TF was performed within a week prior to

Andreas D. Fotopoulos; George A. Alexiou; Ann Goussia; Athanasios Papadopoulos; Athanasios P. Kyritsis; Konstantinos S. Polyzoidis; Spyridon Voulgaris; Spyridon Tsiouris

2008-01-01

323

Tc-99m macro aggregated albumin scintigraphy – indications other than pulmonary embolism: A pictorial essay  

PubMed Central

Introduction: Tc-99m macro aggregated albumin (MAA) is synonymous for lung perfusion scintigraphy and is part of the study in the evaluation of pulmonary thromboembolism. We wanted to highlight the utilities of Tc-99m MAA other than pulmonary embolism as a pictorial assay. Materials and Methods: Patients referred for Tc-99m MAA scintigraphy under various indications were included in this pictorial essay. Commercially available TechneScan LyoMAA cold kit from Mallinckrodt Medical B.V., Holland was used. Acquisition protocols for different indications are described in this article. Different clinical indications (e.g., pulmonary artery stenosis, hepatopulmonary syndrome, FEV1 calculation in lung surgery planning, selective internal radiation therapy planning, venography for deep venous thrombosis, left to right cardiac shunts, etc.) where Tc-99m MAA scintigraphy was asked for; how it helped in different clinical scenarios and how it can be used clinically is explained with unique and interesting case examples and images. We also reviewed the literature to look for certain remote indications of MAA imaging for the sake of completion like – (shunt scintigraphy, peritoneopleural communication, etc.) Conclusion: Tc-99m MAA is a very useful radiopharmaceutical, which can be used for many other indications apart from the commonly used indication of lung perfusion scan in pulmonary embolism. It can provide useful clinical information in other indications, which we try to highlight in this article. PMID:24250023

Gandhi, Sunny J; Babu, Sanjay; Subramanyam, Padma; Shanmuga Sundaram, Palaniswamy

2013-01-01

324

Transport coefficients of heavy quarks around Tc at finite quark chemical potential  

NASA Astrophysics Data System (ADS)

The interactions of heavy quarks with the partonic environment at finite temperature T and finite quark chemical potential ?q are investigated in terms of transport coefficients within the dynamical quasiparticle model (DQPM) designed to reproduce the lattice-QCD (lQCD) results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature Tc. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around Tc at ?q=0 as well as at finite ?q. Close to and above Tc its absolute value matches the lQCD calculations for ?q=0 . The smooth transition of the heavy-quark transport coefficients from the hadronic to the partonic medium corresponds to a crossover in line with lattice calculations, and differs substantially from perturbative-QCD calculations which show a large discontinuity at Tc. This indicates that in the vicinity of Tc dynamically dressed massive partons should be the effective degrees of freedom in the quark-gluon plasma.

Berrehrah, H.; Gossiaux, P. B.; Aichelin, J.; Cassing, W.; Torres-Rincon, J. M.; Bratkovskaya, E.

2014-11-01

325

Accumulation of 99mTc-low-density lipoprotein in human malignant glioma.  

PubMed Central

Low-density lipoprotein (LDL) uptake in gliomas was studied to find out if LDL has potential as a drug carrier of boron, especially for boron neutron capture therapy. Single photon emission tomography (SPET) was performed 2 h and 20 h after intravenous injection of autologous 99mTc-labelled LDL in four patients with untreated and five patients with recurrent glioma. 99mTc-LDL uptake was compared with the uptake of 99mTc-labelled human serum albumin (HSA), an established blood pool marker. The intra- and peritumoral distributions of radioactivity in the SPET images were not identical for radiolabelled LDL and HSA. The mean LDL tumour to brain ratio, determined from transversal SPET slices at 20 h post injection, was 1.5 in untreated and 2.2 in recurrent gliomas; the corresponding ratios for HSA were 1.6 and 3.4. The brain to blood ratio remained constant at 2 h and 20 h in both types of tumours. These data are not consistent with highly selective, homogeneous uptake of LDL in gliomas. However, the different tumoral distribution and rate of uptake of 99mTc-LDL, as compared with 99mTc-HSA, indicate that the uptake of LDL is different from that of HSA and that further studies on the mechanism of LDL uptake in glioma are warranted. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:7841057

Leppälä, J.; Kallio, M.; Nikula, T.; Nikkinen, P.; Liewendahl, K.; Jääskeläinen, J.; Savolainen, S.; Gylling, H.; Hiltunen, J.; Callaway, J.

1995-01-01

326

TOPICAL REVIEW: High-field ?SR studies of superconducting and magnetic correlations in cuprates above Tc  

NASA Astrophysics Data System (ADS)

The advent of high transverse field muon spin rotation (TF-?SR) has led to recent ?SR investigations of the magnetic field response of cuprates above the superconducting transition temperature Tc. Here the results of such experiments on hole-doped cuprates are reviewed. Although these investigations are currently ongoing, it is clear that the effects of high field on the internal magnetic field distribution of these materials is dependent upon competition between superconductivity and magnetism. In La2 - xSrxCuO4 the response to the external field above Tc is dominated by heterogeneous spin magnetism. However, the magnetism that dominates the observed inhomogeneous line broadening below x ~ 0.19 is overwhelmed by the emergence of a completely different kind of magnetism in the heavily overdoped regime. The origin of the magnetism above x ~ 0.19 is probably related to intrinsic disorder, but the systematic evolution of the magnetism with doping changes in the doping range beyond the superconducting 'dome'. In contrast, the width of the internal field distribution of underdoped Y Ba2Cu3Oy above Tc is observed to track Tc and the density of superconducting carriers. This observation suggests that the magnetic response above Tc is not dominated by electronic moments, but rather inhomogeneous fluctuating superconductivity. The spatially inhomogeneous response of Y Ba2Cu3Oy to the applied field may be a means of minimizing energy, rather than being caused by intrinsic disorder.

Sonier, J. E.

2010-05-01

327

Near-yrast, medium-spin structure of the {sup 109}Tc nucleus  

SciTech Connect

Excited levels in the {sup 109}Tc nucleus, populated in the spontaneous fission of {sup 248}Cm, have been studied using the EUROGAM2 array. In {sup 109}Tc we have found a new band corresponding to the {pi}5/2{sup -}[303] configuration and a three-quasiparticle band with I{sup {pi}}=(15/2{sup -}) band-head level at 1749.5 keV. The structure of the 1749.5-keV level probably involves the {l_brace}{pi}5/2{sup +}[422]{nu}(5/2{sup -}[532],5/2{sup +}[413]){r_brace}{sub 15/2}{sup -} prolate configuration. The quasiparticle-rotor model calculations performed in this work show that the odd-proton configurations observed in {sup 107}Tc and {sup 109}Tc are consistent with the scheme of proton excitations in a prolate triaxial potential. Significant differences between the degree of triaxiality observed for positive- and negative-parity excitations may be due to blocking of the triaxial shape by the odd proton populating negative-parity orbitals. The properties of the new 494.5-, 1440.7-, and 1748.8-keV levels found in {sup 109}Tc may indicate a change toward an oblate shape in this nucleus.

Urban, W. [Institut Laue-Langevin, 6 rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Faculty of Physics, University of Warsaw, ul. Hoza 69, PL-00-681 Warsaw (Poland); Pinston, J. A. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier Grenoble 1, Centre National de la Recherche Scientifique/Institut National de Physique Nuclaire et de Physique des Particules, Institut National Polytechnique de Grenoble, F-38026 Grenoble Cedex (France); Rzaca-Urban, T.; Kurpeta, J. [Faculty of Physics, University of Warsaw, ul. Hoza 69, PL-00-681 Warsaw (Poland); Smith, A. G. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Ahmad, I. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2010-12-15

328

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

PubMed Central

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. PMID:24625746

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

2014-01-01

329

The contribution of 99mTc-pyrophosphate tomoscintigraphy in the evaluation of necrotic myocardial lesions.  

PubMed

Diagnostic contribution of Conventional Planar Scintigraphy (CPSc) and Single Photon Emission Computed Tomoscintigraphy (SPECT), using 99mTc-Pyrophosphate (99mTc-PYP), have been compared in 49 patients with either transmural (T.I., N = 40), or non-transmural (N.T.I., N = 9) infarction. Sensitivity ratios were, respectively for CPSc and SPECT, 75% and 100% in T.I., 78% and 88% in N.T.I. CPSc was non-diagnostic in 6 out of 49 patients, SPECT in only 1. Extent of the necrotizing process was better delineated on SPECT studies than on CPSc. Specificity of 99mTc-PYP tomoscintigraphy evaluated in a group of 6 young (under 40 years old) normal patients was 6/6 (100%). In nine out of ten additional patients without proven infarction who had underwent contrast coronarography within two weeks after a positive 99mTc-PYP SPECT study, significant stenosis (greater than 50%) were found on arteries supplying blood to pathologic territories as demonstrated on tomoscans. It is concluded that 99mTc-PYP SPECT is a very sensitive and specific way--better than CPSc--in the diagnosis as well as in the evaluation of the extent of necrotic myocardial process. PMID:2551114

Bourgeois, P; Depaepe, A; Demey, P; Merveille, P; Van Vooren, J P; Frühling, J

1989-01-01

330

Population pharmacokinetics of TC-5214, a nicotinic channel modulator, in phase I and II clinical studies.  

PubMed

TC-5214 (dexmecamylamine) is a nicotinic channel modulator that has previously been evaluated for treatment of major depression disorder (MDD) and is currently being evaluated by Targacept as a treatment for overactive bladder. A comprehensive population pharmacokinetic (POP PK) model of TC-5214 was developed using nonlinear mixed-effects modeling of pooled plasma concentration data from 6 early phase I studies in 179 healthy participants or patients with non-MDD and 1 phase II study in 68 MDD patients. Concentration-time profiles of TC-5214 after either single or multiple oral doses of TC-5214 was described by a one-compartment model with first-order absorption with lag time and first-order elimination. Covariate analysis revealed that creatinine clearance was a significant covariate on clearance and that body weight significantly influenced the central volume of distribution. The final model (with identified covariates) was used to simulate steady-state exposure for patients with impaired renal function. Results from forest plots reveal that patients with moderate to severe renal impairment or end stage renal disease are associated with significantly higher Cssmax and AUC compared to patients with normal renal function. The proposed final POP PK model could be employed in defining a TC-5214 dosage regimen in patients with impaired renal function. PMID:24408516

Xu, Hongmei; Henningsson, Anja; Alverlind, Sofie; Tummala, Raj; Toler, Steven; Beaver, Jessica S; Al-Huniti, Nidal

2014-06-01

331

Measuring Thermal Diffusivity Of A High-Tc Superconductor  

NASA Technical Reports Server (NTRS)

Technique for measuring thermal diffusivity of superconductor of high critical temperature based on Angstrom's temperature-wave method. Peltier junction generates temperature oscillations, which propagate with attenuation up specimen. Thermal diffusivity of specimen calculated from distance between thermocouples and amplitudes and phases of oscillatory components of thermocouple readings.

Powers, Charles E.; Oh, Gloria; Leidecker, Henning

1992-01-01

332

Magnetocumulative generator  

DOEpatents

An improved magnetocumulative generator is described that is useful for producing magnetic fields of very high energy content over large spatial volumes. The polar directed pleated magnetocumulative generator has a housing providing a housing chamber with an electrically conducting surface. The chamber forms a coaxial system having a small radius portion and a large radius portion. When a magnetic field is injected into the chamber, from an external source, most of the magnetic flux associated therewith positions itself in the small radius portion. The propagation of an explosive detonation through high-explosive layers disposed adjacent to the housing causes a phased closure of the chamber which sweeps most of the magnetic flux into the large radius portion of the coaxial system. The energy content of the magnetic field is greatly increased by flux stretching as well as by flux compression. The energy enhanced magnetic field is utilized within the housing chamber itself.

Pettibone, J.S.; Wheeler, P.C.

1981-06-08

333

Cluster generator  

DOEpatents

Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

Donchev, Todor I. (Urbana, IL); Petrov, Ivan G. (Champaign, IL)

2011-05-31

334

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

335

A Novel Phthalimide Derivative, TC11, Has Preclinical Effects on High-Risk Myeloma Cells and Osteoclasts.  

PubMed

Despite the recent advances in the treatment of multiple myeloma (MM), MM patients with high-risk cytogenetic changes such as t(4;14) translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the Cmax was 2.1 ?M at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by ?-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1), whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing. PMID:25617756

Matsushita, Maiko; Ozaki, Yoshie; Hasegawa, Yuka; Terada, Fukiko; Tabata, Noriko; Shiheido, Hirokazu; Yanagawa, Hiroshi; Oikawa, Tsukasa; Matsuo, Koichi; Du, Wenlin; Yamada, Taketo; Hozumi, Masashi; Ichikawa, Daiju; Hattori, Yutaka

2015-01-01

336

A Novel Phthalimide Derivative, TC11, Has Preclinical Effects on High-Risk Myeloma Cells and Osteoclasts  

PubMed Central

Despite the recent advances in the treatment of multiple myeloma (MM), MM patients with high-risk cytogenetic changes such as t(4;14) translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the Cmax was 2.1 ?M at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by ?-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1), whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing. PMID:25617756

Matsushita, Maiko; Ozaki, Yoshie; Hasegawa, Yuka; Terada, Fukiko; Tabata, Noriko; Shiheido, Hirokazu; Yanagawa, Hiroshi; Oikawa, Tsukasa; Matsuo, Koichi; Du, Wenlin; Yamada, Taketo; Hozumi, Masashi; Ichikawa, Daiju; Hattori, Yutaka

2015-01-01

337

Majority of TcRbeta+ T-lymphocytes located in thymus and midgut of the bony fish, Dicentrarchus labrax (L.).  

PubMed

Real-time polymerase chain reaction (PCR) and in situ hybridization analyses were performed to investigate the occurrence and distribution of T-lymphocytes expressing TcRbeta in intestine and lymphoid tissues of the bony fish, Dicentrarchus labrax (sea bass). Immunohistochemistry with the monoclonal antibody DLT15 (pan-T-cell marker) was carried out to compare the cytology, distribution and number of T-cells and TcRbeta+ cells in the various sampled lymphoid organs. The highest TcRbeta expression was revealed by real-time PCR in the thymus, with high levels also being found in the gut. In the thymus, DLT15+ and TcRbeta+ cell populations were concentrated in the cortex and TcRbeta+ cells were notably reactive at the cortical-medullary border, suggesting a specialized role of this region in thymocyte selection. The density of DLT15+ T-cells increased from the anterior to posterior intestine, whereas TcRbeta+ lymphocytes were more numerous in the middle intestine compared with other segments. The existence, in fish thymus, of a medulla and a cortex comparable with those of mammals is revealed by this study. The concentration of TcRbeta+ cells in the sea bass midgut also strongly suggests a special role of this intestinal segment in antigen-specific cellular immunity. The large population of TcRbeta(-)/DLT15+ T-cells in the posterior gut can probably be ascribed to the TcRgammadelta phenotype fraction. PMID:17549519

Romano, Nicla; Rossi, Francesca; Abelli, Luigi; Caccia, Elisabetta; Piergentili, Rita; Mastrolia, Lucia; Randelli, Elisa; Buonocore, Francesco

2007-09-01

338

Technetium99m generator based on 12-molybdocerate — 99 Mo precipitate as column matrix  

Microsoft Academic Search

The preparation of insoluble 12-molybdocerate(IV) from99Mo of low specific activity, produced by thermal neutron irradiation of MoO3, is described. Samples of the material are dried at 50, 100 and 200°C and used as column matrices from which the generated99mTc activity is periodically eluted with saline solution or saline solution containing 5·10–5M K2CrO4 as an oxidant. The elution yields of99mTc are

M. A. El Absy; I. M. El Naggar; A. I. Audah

1993-01-01

339

Antilymphocyte autoantibodies generate T cell-C4d signatures in systemic lupus erythematosus.  

PubMed

T cells bearing C4d, a complement activation product (CAP), have been shown to be highly sensitive and specific as diagnostic biomarkers for systemic lupus erythematosus (SLE). T cells bearing C4d are also functionally abnormal, suggesting a role for cell-bound CAPs in lupus pathogenesis. However, the mechanism responsible for generation of T-C4d has not been determined. The purpose of this cross-sectional and prospective study was to investigate the potential role of anti-T-cell autoantibodies in the generation of the T cell-bound C4d (T-C4d) signatures in SLE. Briefly, T cells from patients with SLE (n = 326), patients with other inflammatory diseases (n = 185), and healthy controls (n = 48) were characterized for surface deposition of either or both of C4d and immunoglobulin (Ig) by flow cytometry. In vitro phenotype transfer experiments were performed to characterize Ig from patients with SLE for the capacity to generate T-C4d signatures in vitro. The results demonstrate that individual patients with SLE harbor specific signatures reflecting the presence of either or both of C4d and Ig on their T cells and T-cell subsets. In addition, SLE patient-specific signatures can be transferred in vitro to normal T cells by exposure to Ig purified from the signature donor. Complement activation does not proceed through the generation of C5b-9 (membrane attack complex) or cellular lysis, and T-C4d does not correlate with lymphopenia. In conclusion, these results suggest that patient-specific T-C4d signatures are generated by anti-T-cell autoantibodies that trigger sublytic complement activation, a previously unrecognized pathway in lupus pathogenesis. PMID:25168018

Liu, Chau-Ching; Manzi, Susan; Ahearn, Joseph M

2014-12-01

340

Scintigraphy with 99mTc(V)-DMSA in monitoring patients with inflammatory bowel disease.  

PubMed

The clinical significance of pentavalent technetium-99m dimercaptosuccinic acid (99mTc(V)-DMSA) scintigraphy in diagnosing inflammatory bowel disease (IBD) has not yet been fully elucidated. The aim of this prospective paper was to study the above. This study included 54 patients, 22 females and 32 males (mean age: 36.68±11.49; range: 18-63 years) with IBD who came to our clinics for follow-up and were examined clinically by colonoscopy and 99mTc(V)-DMSA scintigraphy. On the follow-up studies, five patients (9.25%) relapsed, and 49 (90.74%) remained at a steady condition. There was a good correlation between the scintigraphic results and the clinical and colonoscopy data of the patients (P<0.05). In conclusion, our results indicated that 99mTc(V)DMSA scintigraphy can be complementary to colonoscopy for the diagnostic evaluation of IBD. PMID:24251309

Javadi, Hamid; Amiriani, Taghi; Mirkarimi, HoneySadat; Besharat, Sima; Semnani, Shahriar; Abedi, Jamshid; Seyedabadi, Mohammad; Assadi, Majid

2013-01-01

341

Universal inhomogeneous magnetic-field response in the normal state of cuprate high-Tc superconductors  

NASA Astrophysics Data System (ADS)

We report the results of a muon spin rotation (?SR) study of the bulk of Bi2+xSr2-xCaCu2O8+?, as well as pure and Ca-doped YBa2Cu3Oy, which together with prior measurements reveal a universal inhomogeneous magnetic-field response of hole-doped cuprates extending to temperatures far above the critical temperature Tc. The primary features of our data are incompatible with the spatially inhomogeneous response being dominated by known charge-density-wave and spin-density-wave orders. Instead, the normal-state inhomogeneous line broadening is found to scale with the maximum value Tcmax for each cuprate family, indicating it is controlled by the same energy scale as Tc. Since the degree of chemical disorder varies widely among the cuprates we have measured, the observed scaling constitutes evidence for an intrinsic electronic tendency toward inhomogeneity above Tc.

Mahyari, Z. Lotfi; Cannell, A.; de Mello, E. V. L.; Ishikado, M.; Eisaki, H.; Liang, Ruixing; Bonn, D. A.; Sonier, J. E.

2013-10-01

342

Local magnetization of dilute Fe in Tc, Ru, and Ir from Moessbauer measurements  

SciTech Connect

The magnetic character of the localized spin-fluctuation systems TcFe, RuFe, and IrFe has been investigated by Moessbauer experiments between 1.4 and 290 K in external magnetic fields up to 50 kOe. Saturation values of the hyperfine fields in 50 kOe are -7.3 +- 1 kOe for TcFe and -9.3 +- 1 kOe for IrFe, which are much smaller than those of usual Kondo systems. For Tc and Ir hosts, the saturation values are proportional to the external field, and this property closely resembles Kondo systems like CuFe and RhFe. For Ru host, the observed small and temperature-independent hyperfine field ( vertical-bar H/sub hf/ vertical-bar <2 kOe) is consistent with the extremely high spin-fluctuation temperature.

Takabatake, T.; Mazaki, H.; Shinjo, T.

1980-04-01

343

Chemical Equilibration and Transport Properties of Hadronic Matter near $T_c$  

E-print Network

We discuss how the inclusion of Hagedorn states near $T_c$ leads to short chemical equilibration times of proton anti-proton pairs, $K\\bar{K}$ pairs, and $\\Lambda\\bar{\\Lambda}$ pairs, which indicates that hadrons do not need to be "born" into chemical equilibrium in ultrarelativistic heavy ion collisions. We show that the hadron ratios computed within our model match the experimental results at RHIC very well. Furthermore, estimates for $\\eta/s$ near $T_c$ computed within our resonance gas model are comparable to the string theory viscosity bound $\\eta/s=1/4\\pi$. Our model provides a good description of the recent lattice results for the trace anomaly close to $T_c=196$ MeV.

J. Noronha-Hostler; J. Noronha; H. Ahmad; I. Shovkovy; C. Greiner

2009-07-28

344

Fermi-surface induced variation in Tc in MgB 2 alloys  

NASA Astrophysics Data System (ADS)

Using a coherent potential to describe disorder, the Gaspari-Gyorffy approach to evaluate electron-phonon coupling, and the Allen-Dynes equation to calculate Tc, we show that in Mg 1- xM xB 2 (M?Al, Li or Zn) alloys (i) the way Tc changes depends on the location of the added/modified k-resolved states on the Fermi surface and (ii) the variation of Tc as a function of concentration is dictated by the B p density of states. In addition, using pseudopotential calculations for MgMB 4, we show that (i) at x=0.5 a superstructure can form in Mg 1- xAl xB 2 but not in Mg 1- xLi xB 2 or Mg 1- xZn xB 2, and (ii) B layer shifts towards the impurity layer, more for Al than for Li or Zn.

Singh, Prabhakar P.

2002-11-01

345

A novel approach to infection imaging using a synthetic Tc-99m-labeled leukotactic peptide  

SciTech Connect

RMT1, a synthetic peptide binding to PMN and macrophage receptors was labeled with Tc-99m and investigated as a potential imaging agent for abscess and inflammation. Experimental abscesses were induced in rabbits and dogs by turpentine and E.coli injection. After injection of Tc-99m-RMT1 two and twelve day old abscesses were visualized within 20 min. In initial studies, a dose of 30 {mu}g of peptide/3 mCi was used. This amount was subsequently reduced to 1.5 {mu}g peptide with same amount of Tc-99m yielding similar imaging results. Technetium-99m-IgG and Tc-99m-MAG-3 were used as positive and negative controls, respectively. After injection of IgG abscesses were visualized but activity in blood was always higher than in abscess. When using Tc-99m RMT1 rapid abscess visualization and faster blood clearance was observed. The accumulation of RMT1 was monophasic, i.e., following the initial visualization, activity continued to build up continuously for 1{1/2} hr. Tc-99m-MAG3 accumulated initially in abscess, but activity washed out. In dogs, RMT1 blood clearance showed three components: a fast component with t{1/2}=1.9 min, 73%, intermediate t{1/2}=22 min, 24.5% and slow component, t{1/2}=115, 9.5% with 3 hours cumulative urine excretion of 40-51%. RMT1 appears to be more advantageous than currently available methods because of rapidity of imaging, simpler preparation before injection and will probably be less expensive and time consuming compared to labeled WBC. These results indicate that clinical experiments are warranted.

Som, P.; Oster, Z.H.; Sharma, S. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States)]|[Rhomed, Inc., Albuquerque, NM (United States)] [and others

1996-05-01

346

Tc(VII) reduction kinetics by titanomagnetite (Fe3-xTixO4) nanoparticles  

NASA Astrophysics Data System (ADS)

Technetium contamination remains a major environmental problem at nuclear reprocessing sites, such as at the Hanford nuclear reservation, Washington, USA. Here we investigate the heterogeneous reduction of the highly soluble pertechnetate anion [Tc(VII)O4-] to sparingly soluble Tc(IV)-bearing solids by a novel and well-characterized set of mixed-valent titanium-doped magnetite nanoparticles, structurally and chemically analogous to titanomagnetites naturally present in Hanford sediments. Titanomagnetite (Fe3-xTixO4) nanoparticles (10-12 nm) with varying Ti content (0 ? x ? 0.53) were synthesized in aqueous suspension. Reaction with 10 and 30 ?M Tc(VII) solution yielded fast exponentially decaying reduction kinetics with rates that increased with increasing solid-state Fe(II)/Fe(III) ratio in the nanoparticles, a characteristic systematically controlled by the Ti-content. Nanoparticles before and after reduction experiments and surface-associated products of Tc(VII) reduction were characterized using transmission electron microscopy (TEM), X-ray absorption near-edge spectroscopy (XANES), extended X-ray absorption fine structure spectroscopy (EXAFS), micro X-ray diffraction (?-XRD), X-ray absorption (XA) and X-ray magnetic circular dichroism (XMCD). A mechanistic reaction model was developed involving reduction of Tc(VII) to form Tc(IV)/Fe(III) solids by structural Fe(II) enriched at the nanoparticle surface, a reactive Fe(II) pool that during reaction is resupplied and sustained by outward migration of Fe(II) from the particle interior with concurrent inward migration of charge-balancing cationic vacancies in a ratio of 3:1. The reaction process was quantitatively linked to mass and electron balanced changes in the Fe3-xTixO4 nanoparticles, and the accessibility of structural Fe(II) from these phases was determined.

Liu, J.; Pearce, C. I.; Qafoku, O.; Arenholz, E.; Heald, S. M.; Rosso, K. M.

2012-09-01

347

Efficacy of (99m)Tc-EDDA/HYNIC-TOC SPECT/CT scintigraphy in Graves' ophthalmopathy.  

PubMed

The aim of this study was to investigate the predictive role of the orbital somatostatin receptor scintigraphy with (99m)Tc-EDDA/HYNIC-TOC ((99m)Tc-TOC) to detect clinical stage of Graves' ophthalmopathy and the response to corticosteroid therapy. The subjects of the experiment were 46 patients with Graves' ophthalmopathy (GO) and four volunteers without eye disease or GO as the normal group (NG). Single photon emission computed tomography (SPECT), computed tomography (CT) and the left and right lateral position planar imaging of the heads of the all subjects were obtained 4 h after the intravenous injection of 555 MBq of (99m)Tc-TOC. The (99m)Tc-TOC SPECT/CT was repeated 3 months later. 35 (35/46) patients were received corticosteroid therapy (prednisolone, 10 mg po tid ) for 3 months, however, the other 11 patients as control groups did not receive any treatment. The treatment effect was evaluated both by the orbital (99m)Tc-TOC uptake and NOSPECS. A significant decrease in the O/OC ratio was observed in 22 GO patients between pre- and post-treatment (1.64 ± 0.13 vs. 1.21 ± 0.09, P < 0.05). There were neither significant difference of the O/OC ratio in 13 GO patients between pre- and post-treatment periods, nor significant difference in the 9 (9/11) patients before and after three months. Orbital (99m)Tc-TOC scintigraphy is a feasible technique to estimate the Graves' ophthalmopathy activity and predict the response to subsequent corticosteroid therapy in GO patients. The technique could be a useful tool for physicians not familiar with CAS determination. PMID:23133815

Zhao, Rong; Wang, Jiang; Deng, Jinglan; Yang, Weidong; Wang, Jing

2012-01-01

348

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

349

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

350

Smoke generator  

NASA Technical Reports Server (NTRS)

A smoke generator is disclosed which is particularly suitable for mounting on the wing tips of an aircraft and for conducting airflow studies. The device includes a network of thermally insulated tubes for carrying a fluid which is used to produce smoke. The fluid, which need not be combustible, is heated above its vaporization temperature by electric current which is passed through the fluid conduit tubes, so that the tubes serve both as fluid conduits and resistance heating elements. Fluid supply and monitoring systems and electrical control systems are also disclosed.

Rogers, J. R. (inventor)

1976-01-01

351

17O and 63Cu NMR Investigations of High-Tc Superconductor La1.85Sr0.15CuO4 with Tc{=}38 K  

Microsoft Academic Search

17O and 63Cu NMR measurements have been made in L1.85Sr0.15CuO4 with Tc{=}38 K. Both 17O Knight shift and quadrupole tensor were determined from the analyses of the 17O spectrum of oriented powder. The quadrupole frequencies of the planar oxygen and Cu nuclei are consistently interpreted by the analyses of Hanzawa et al. made in YBa2Cu3O7 with the electric field gradients

Kenji Ishida; Yoshio Kitaoka; Guo-qing Zheng; Kunisuke Asayama

1991-01-01

352

Abnormal retention of 99m Tc-TF in a hamster model of cardiomyopathy analyzed by 99m Tc-TF and 125 I-BMIPP autoradiography  

Microsoft Academic Search

Objective: Enhanced washout of99mTc-tetrofosmin (TF) has been reported in patients with hypertrophic cardiomyopathy (HCM). Here, using quantitative dual-autoradiography,\\u000a the relationship between TF retention abnormality and metabolism depicted by125I-BMIPP uptake was investigated quantitatively in a hamster model of cardiomyopathy.Methods and\\u000a Results: Early and delayed TF images were obtained at 5 min (7 cardiomyopathic and 5 normal hamsters) and 60 min (8

Lwin Thet-Thet; Tohoru Takeda; Jin Wu; Yoshinori Tsuchiya; Yuji Itai

2004-01-01

353

Systematics in positron annihilation lifetime analysis of high (Tc) superconducting transitions  

NASA Astrophysics Data System (ADS)

The lifetimes and momentum distributions of annihilating electron-positron pairs are changed in high Tc superconductors cooled below the superconducting transition. Since the initial observation of this phenomena is YBCO the observation of these effects was reproduced and extended to other high (Tc) systems. There is a general consistency of results in most families of superconductors. An exception to this is YBCO which shows strong sample dependence. These consistent features have led to a model relating the pairing of the positive charge carriers and the positron distribution as one explanation for the lifetime changes.

Howell, R. H.; Radousky, H. B.; Wachs, A. L.; Fluss, M. J.; Turchi, P. E. A.; Jean, Y. C.; Sundar, C. S.; Chu, C. W.; Shelton, R. N.; Hinks, D. G.

1989-06-01

354

Vesicocolic fistula detected by (99m)Tc-MAG3 renogram.  

PubMed

A 55-year-old man presented with 60-lb weight loss in 6 months. An abdominal CT demonstrated a large mass in the pelvis arising from the sigmoid colon and invading the urinary bladder. His elevated serum creatinine (1.25 mg/dL) triggered a request for a Tc-MAG3. Tc-MAG3 renogram demonstrated communication of the urinary bladder with the descending colon but no evidence of obstruction to drainage from the kidneys to the bladder. A retrograde cystogram confirmed a vesicocolic fistula. After multiple rounds of chemotherapy, the patient died 7 months later. PMID:25140566

Mannelli, Lorenzo; Monti, Serena; Bastawrous, Sarah; Lomabardo, Ivano; Behnia, Fatemeh

2015-01-01

355

Intraperitoneal urine leak after prostatectomy confirmed by 99mTc-MAG3 renogram.  

PubMed

A 67-year-old patient presented with abdominal pain and distension 2 days after robotic radical prostatectomy for prostate carcinoma. He became anuric, and his serum creatinine level doubled, making IV contrast contraindicated. Abdominal CT without contrast demonstrated hypodense fluid in the peritoneum. Tc-MAG3 renogram detected extravasation of radiotracer from the bladder. Follow-up retrograde cystogram revealed a posterior anastomotic leak. The patient underwent uneventful surgical repair and made a full recovery. This case demonstrated that Tc-MAG3 can prove leak from the urinary tract, particularly helpful in the setting of poor renal function and contraindication to IV contrast. PMID:24873796

Pogatchnik, Brian; Monti, Serena; Lewis, David H; Heinrich, Demetra A; Mannelli, Lorenzo

2014-08-01

356

Quantum melting of the vortex lattice in high-Tc superconductors  

NASA Astrophysics Data System (ADS)

In the new high-Tc superconductors both thermal as well as quantum fluctuations are large. The latter smear the vortex cores over a distance of the order of the coherence length and thereby strongly affect the melting transition. Taking account of quantum fluctuations, the shape of the melting line is given by a universal function which is different from a simple power law in 1 - T/Tc and is in excellent agreement with recent experiments on YBa2Cu3O(7-delta) single crystals. Above a crossover field of the order of a few tesla the resulting high-temperature phase is a quantum liquid.

Blatter, Gianni; Ivlev, Boris

1993-04-01

357

Investigation of alternative production routes of 99mTc: deuteron induced reactions on 100 Mo.  

PubMed

Activation cross sections of deuteron induced nuclear reactions on enriched (100)Mo have been studied up to 50 MeV using the stacked foil irradiation technique and gamma spectroscopy. The excitation functions for production of (99m)Tc, (ind99)Mo, (ind98m)Nb, (ind97mg)Nb radioisotopes were measured for the first time and compared with the results of the ALICE-D, EMPIRE-D and TALYS codes. Production possibilities of the medically important (99m)Tc are discussed. PMID:20817541

Tárkányi, F; Hermanne, A; Takács, S; Sonck, M; Szucs, Z; Király, B; Ignatyuk, A V

2011-01-01

358

Unusual Tc-99m MDP and I-123 MIBG images in focal pyelonephritis  

SciTech Connect

A 6-year-old boy presented with an inflammatory syndrome. Because Tc-99m MDP bone scintigraphy revealed increased tracer uptake at the upper pole of the right kidney, further studies were oriented towards a diagnosis of renal or adrenal pathology. I-123 metaiodobenzylguanidine (MIBG) accumulated at the site of the abnormal MDP uptake. The diagnosis of neuroblastoma or allied disorder was excluded on the basis of other investigations and further evaluation, suggesting that the MIBG uptake was a false-positive. Findings on clinical imaging, laboratory findings, Tc-99m DMSA imaging, sonography, and CT scanning were highly suggestive of acute focal pyelonephritis.

Jacobs, A.; Lenoir, P.; Delree, M.; Ramet, J.; Piepsz, A. (Vrije Universiteit, Brussel (Belgium))

1990-11-01

359

Renal accumulation of /sup 99m/Tc-DMSA in the artificially perfused isolated rat kidney  

SciTech Connect

In order to investigate aspects of the renal handling of /sup 99m/Tc-DMSA, 68 isolated rat kidneys were artificially perfused. The experimental groups were: Group 1 (no. = 32)-oxygenated filtering kidneys; Group 2 (no. = 29)-oxygenated non-filtering kidneys; Group 3 (no. = 7)-anaerobic non-filtering kidneys. The authors conclude that the /sup 99m/Tc-DMSA complex is strongly bound to albumin, is not filtered and is removed from perfusion fluid through the renal peritubular capillary route and that this occurs by an active process which depends upon aerobic metabolism. This process has a high capacity and is not inhibited by probenecid.

Goldraich, N.P.; Alvarenga, A.R.; Goldraich, I.H.; Ramos, O.L.; Sigulem, D.

1985-12-01

360

Role of histamine H3 receptor in glucagon-secreting ?TC1.6 cells  

PubMed Central

Pancreatic ?-cells secrete glucagon to maintain energy homeostasis. Although histamine has an important role in energy homeostasis, the expression and function of histamine receptors in pancreatic ?-cells remains unknown. We found that the histamine H3 receptor (H3R) was expressed in mouse pancreatic ?-cells and ?TC1.6 cells, a mouse pancreatic ?-cell line. H3R inhibited glucagon secretion from ?TC1.6 cells by inhibiting an increase in intracellular Ca2+ concentration. We also found that immepip, a selective H3R agonist, decreased serum glucagon concentration in rats. These results suggest that H3R modulates glucagon secretion from pancreatic ?-cells.

Nakamura, Tadaho; Yoshikawa, Takeo; Naganuma, Fumito; Mohsen, Attayeb; Iida, Tomomitsu; Miura, Yamato; Sugawara, Akira; Yanai, Kazuhiko

2014-01-01

361

[Differential expression of DTSsa4 Tc1-like transposons in closely related populations of Baikal ciscoes].  

PubMed

Two representatives of Baikal ciscoes - lake cisco and omul - diverged from a common ancestor as recently as 10-20 thousand years ago. We have found an increasing expression level of DTSsa4 Tc1-like DNA transposons in cisco and omul brains. The mapping of the sequences of these transposons from Salmo salar and Danio rerio genomes has shown that in some cases, these transposons are located in the 5' and 3' regions, as well as in the promoter regions of various genes. Probably, Tc1-like transposons affect the activity of neighboring genes, providing the adaptive divergence of the cisco population. PMID:20208586

Bychenko, O S; Sukhanova, L V; Azhikina, T L; Sverdlov, E D

2009-01-01

362

Synchronous thoracic and abdominal enteric duplication cysts: Accurate detection with 99mTc-pertechnetate scintigraphy  

PubMed Central

Enteric duplication cysts (EDCs) are uncommon congenital anomalies, which can occur anywhere along the gastrointestinal tract and vary greatly in presentation, size, location and symptoms. Ectopic gastric mucosa is reported to be found in 20-30% of these duplications. 99mTc-pertechnetate scintigraphy is a useful modality for preoperative localization of the ectopic functioning gastric mucosa in the EDCs. We report a case where 99mTc-pertechnetate scintigraphy was useful in detecting synchronous thoracic and abdominal duplication cysts with functioning gastric mucosa thus having an impact on the patient management. PMID:25589809

Kumar, Kunal; Dhull, Varun Singh; Karunanithi, Sellam; Chakraborty, Partha Sarathi; Roy, Shambo Guha; Ghosh, Shouriyo; Agarwala, Sandeep; Tripathi, Madhavi

2015-01-01

363

Scintigraphic detection of pulmonary hemorrhage using Tc-99m-sulfur colloid  

SciTech Connect

Pulmonary hemorrhage, whether in the form of hemoptysis or bleeding into the pleural space, may be a life threatening problem. While fiberoptic bronchoscopy and selective bronchial and intercostal angiography are the major diagnostic modalities, these techniques are not without risks. Two patients are described-one with massive hemoptysis from a bronchogenic carcinoma; another with pleural bleeding from a torn intercostal artery-in whom Tc-99m-sulfur colloid scintigraphy accurately located the source of hemorrhage. We conclude that Tc-99m-sulfur colloid scintigraphy may be a helpful noninvasive method to increase the sensitivity and specificity of fiberoptic bronchoscopy and bronchial angiography in patients with massive pulmonary bleeding.

Winzelberg, G.G.; Wholey, M.H.

1981-11-01

364

Unusual persistence of Tc-99m MDP uptake in the incisional scar after thoracotomy  

SciTech Connect

Postoperative scar is one of the causes of extraosseous localization of Tc-99m phosphonate bone agents. Usually, an incisional scar will not be visualized in a Tc-99m phosphonate skeletal image two weeks after surgery. A case is reported with an unusually persistent localization of radiotracer in the scar of a thoracotomy seen in three consecutive bone images done beyond two weeks postoperatively. This patient suffered from ''pulmonary insufficiency'' before and after the thoracotomy. The abnormal radiotracer localization in the scar is presumably related to his pulmonary insufficiency, with resulting relatively delayed wound healing.

Shih, W.J.; DeLand, F.H.; Domstad, P.A.; Dillon, M.L.

1984-10-01

365

Magnetocumulative generator  

DOEpatents

An improved magnetocumulative generator is described that is useful for producing magnetic fields of very high energy content over large spatial volumes. The polar directed pleated magnetocumulative generator has a housing (100, 101, 102, 103, 104, 105) providing a housing chamber (106) with an electrically conducting surface. The chamber (106) forms a coaxial system having a small radius portion and a large radius portion. When a magnetic field is injected into the chamber (106), from an external source, most of the magnetic flux associated therewith positions itself in the small radius portion. The propagation of an explosive detonation through high-explosive layers (107, 108) disposed adjacent to the housing causes a phased closure of the chamber (106) which sweeps most of the magnetic flux into the large radius portion of the coaxial system. The energy content of the magnetic field is greatly increased by flux stretching as well as by flux compression. The energy enhanced magnetic field is utilized within the housing chamber itself.

Pettibone, Joseph S. (Livermore, CA); Wheeler, Paul C. (Livermore, CA)

1983-01-01

366

Novel cyclopentadienyl tricarbonyl (99m)tc complexes containing 1-piperonylpiperazine moiety: potential imaging probes for sigma-1 receptors.  

PubMed

We report the design, synthesis, and evaluation of a series of novel cyclopentadienyl tricarbonyl (99m)Tc complexes as potent ?1 receptor radioligands. Rhenium compounds 3-(4-(1,3-benzodioxol-5-ylmethyl)piperazin-1-yl)propylcarbonylcyclopentadienyl tricarbonyl rhenium (10a) and 4-(4-(1,3-benzodioxol-5-ylmethyl)piperazin-1-yl)butylcarbonylcyclopentadienyl tricarbonyl rhenium (10b) possessed high in vitro affinity for ?1 receptors and moderate to high selectivity for ?2 receptors and the vesicular acetylcholine transporter. Biodistribution studies in mice demonstrated high initial brain uptake for corresponding (99m)Tc derivatives [(99m)Tc]23 and [(99m)Tc]24 of 2.94 and 2.13% injected dose (ID)/g, respectively, at 2 min postinjection. Pretreatment of haloperidol significantly reduced the radiotracer accumulation of [(99m)Tc]23 or [(99m)Tc]24 in the brain. Studies of the cellular uptake of [(99m)Tc]23 in C6 and DU145 tumor cells demonstrated a reduction of accumulation by incubation with haloperidol, 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine (SA4503), or 1,3-di-o-tolyl-guanidine (DTG). Furthermore, blocking studies in C6 glioma-bearing mice confirmed the specific binding of [(99m)Tc]23 to ?1 receptors in the tumor. PMID:25073047

Wang, Xia; Li, Dan; Deuther-Conrad, Winnie; Lu, Jie; Xie, Ying; Jia, Bing; Cui, Mengchao; Steinbach, Jörg; Brust, Peter; Liu, Boli; Jia, Hongmei

2014-08-28

367

Improving the sensitivity of a high-Tc SQUID at MHz frequency using a normal metal transformer  

Microsoft Academic Search

Superconducting quantum interference devices (SQUIDs) can be used to detect the signals of nuclear quadrupole resonance (NQR). The NQR frequencies of some interesting materials are in the order of MHz. However, the sensitivity of a high-Tc SQUID is normally not enough to detect the weak NQR signals. To improve the sensitivity of a high-Tc SQUID at MHz frequency, we used

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

2006-01-01

368

Interleukin-1B-31T/C promoter polymorphism and chronic obstructive pulmonary disease risk: a meta-analysis  

PubMed Central

Introduction The role of interleukin (IL)-1? –31T/C promoter polymorphism in the pathogenesis of chronic obstructive pulmonary disease (COPD) has been studied with inconsistent results. This meta-analysis was performed to assess the association of IL-1? –31T/C promoter polymorphism with COPD susceptibility. Material and methods Published case-control studies from PubMed and China National Knowledge Infrastructure (CNKI) databases were retrieved. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Results Six case-control studies were included in this meta-analysis. The pooled effect size showed that IL-1? -31T/C was significantly associated with COPD susceptibility in an overdominant genetic model (CC+TT vs. TC, OR: 0.77, 95% CI: 0.63–0.94), indicating that homozygotes (CC and TT) had a decreased risk for COPD compared with heterozygotes (TC). In the subgroup analysis by ethnicity, the results indicated that IL-1? –31T/C was significantly correlated with COPD susceptibility in Asians (overdominant model, OR: 0.75, 95% CI: 0.61–0.93), further suggesting a protective role of IL-1? –31T/C in COPD pathogenesis in Asians. Moreover, after excluding the study without Hardy-Weinberg equilibrium, the pooled results were robust and no publication bias was found in this study. Conclusions This meta-analysis suggests that IL-1? –31T/C promoter polymorphism confers protection against COPD in Asians. PMID:25097571

Xiao, Min; Guo, Lingli; Wang, Tao; Zhu, Tao; Jia, Liuqun; Chen, Lei

2014-01-01

369

(99m)Tc-MIBI emboli in the lungs detected on SPECT/CT: a pitfall in parathyroid scan.  

PubMed

Although we are familiar with artifactual, focal pulmonary F-FDG accumulations without an apparent underlying pathologic finding, similar artifact for Tc-MIBI has not been described yet. Herein, we reported incidental detection of Tc-MIBI emboli in the lungs on parathyroid SPECT/CT. PMID:24300351

Aras, Mustafa; Erdil, Tanju Yusuf; Ones, Tunc; Dede, Fuat; Turoglu, Halil Turgut

2014-02-01

370

Lung uptake on Tc-99m albumin colloid liver spleen scan and on Ga-67 scan in angiotropic lymphoma  

SciTech Connect

Lung uptake of Tc-99m sulfur colloid has been reported in various hepatic and extrahepatic diseases, and lung uptake of gallium-67 may occur in patients with various interstitial lung disease without radiographic abnormality. This may be the first case of Tc-99m albumin colloid and Ga-67 lung uptake in a patient with angiotropic lymphoma of the liver, spleen, and uterus.

Kacki, M.H.; Joyce, J.M.; Coupal, J.J.; Ryo, U.Y. (Univ. of Kentucky Medical Center, Lexington (USA))

1990-03-01

371

The importance of Tc-MAA SPECT/CT for therapy planning of radioembolization in a patient treated with bevacizumab.  

PubMed

A 76-year-old man with colorectal cancer and hepatic metastases was referred to us for radioembolization of the liver. Angiography with 99mTc-MAA SPECT/CT was performed 8 weeks after the discontinuation of bevacizumab. 99mTc-MAA SPECT/CT showed a diffused intrahepatic tracer distribution with no focally accentuated accumulation in the tumorous region. The test was repeated 6 weeks later and Tc-MAA SPECT/CT showed this time a tumor accentuated tracer accumulation in the liver. Subsequently, the patient was treated with resin microspheres. Tc-MAA SPECT/CT allows a better evaluation of intrahepatic tracer accumulation of Tc-MAA and facilitates the determination of the most appropriate treatment time. PMID:22996246

Ahmadzadehfar, Hojjat; Sabet, Amir; Meyer, Carsten; Habibi, Elham; Biersack, Hans-Jürgen; Ezziddin, Samer

2012-11-01

372

Migrating data from TcSE to DOORS : an evaluation of the T-Plan Integrator software application.  

SciTech Connect

This report describes our evaluation of the T-Plan Integrator software application as it was used to transfer a real data set from the Teamcenter for Systems Engineering (TcSE) software application to the DOORS software application. The T-Plan Integrator was evaluated to determine if it would meet the needs of Sandia National Laboratories to migrate our existing data sets from TcSE to DOORS. This report presents the struggles of migrating data and focuses on how the Integrator can be used to map a data set and its data architecture from TcSE to DOORS. Finally, this report describes how the bulk of the migration can take place using the Integrator; however, about 20-30% of the data would need to be transferred from TcSE to DOORS manually. This report does not evaluate the transfer of data from DOORS to TcSE.

Post, Debra S. (Sandia National Laboratories, Livermore, CA); Manzanares, David A.; Taylor, Jeffrey L.

2011-02-01

373

Density of states and superconductivity in ScTc/sub 2/ and ScRe/sub 2/  

SciTech Connect

The low-temperature specific heats of ScTc/sub 2/ and ScRe/sub 2/ are reported. The newly discovered record high T/sub c/ for a Laves phase (10.9 K) in ScTc/sub 2/ is explained qualitatively by its factor of two larger N(0) than in ScRe/sub 2/ (T/sub c/ = 0.93 K). Comparison of the data for ScTc/sub 2/, with that for HfV/sub 2/(T/sub c/ = 8.4 K), which has three times the N(0) as for ScTc/sub 2/, suggests that the electron-phonon coupling strength is also an important factor in the high T/sub c/ of ScTc/sub 2/.

Stewart, G.R.; Cort, B.; Szklarz, E.G.; Giorgi, A.L.

1982-03-01

374

Quantum melting of the vortex lattice in high-Tc superconductors  

Microsoft Academic Search

In the new high-Tc superconductors both thermal as well as quantum fluctuations are large. The latter smear the vortex cores over a distance of the order of the coherence length and thereby strongly affect the melting transition. Taking account of quantum fluctuations, the shape of the melting line is given by a universal function which is different from a simple

Gianni Blatter; Boris Ivlev

1993-01-01

375

Complete genome sequence of Alicyclobacillus acidocaldarius strain Tc-4-1.  

PubMed

Alicyclobacillus acidocaldarius strain Tc-4-1 was initially isolated from a hot spring in Tengchong, China. This organism is both thermophilic and acidophilic. It can produce heat- and acid-stable enzymes, such as amylase and esterase, which may be important in industry. Here we report the whole genome sequence of the strain. PMID:21914900

Chen, Yaping; He, Yongzhi; Zhang, Bing; Yang, Jin; Li, Wenjie; Dong, Zhiyang; Hu, Songnian

2011-10-01

376

Text classification Naive Bayes NB theory Evaluation of TC naive bayes document claasification  

E-print Network

of how search engines use classification Language identification (classes: English vs. French etcText classification Naive Bayes NB theory Evaluation of TC naive bayes document claasification Most, 2014 naive bayes document claasification 1 / 52 #12;Text classification Naive Bayes NB theory

Lu, Jianguo

377

Recap Text classification Naive Bayes NB theory Evaluation of TC Introduction to Information Retrieval  

E-print Network

classification Naive Bayes NB theory Evaluation of TC Query expansion at search engines Main source of query The user issues a (short, simple) query. The search engine returns a set of documents. User marks some docs as relevant, some as nonrelevant. Search engine computes a new representation of the information need ­ should

Nejdl, Wolfgang

378

Magnetic Microscopy and Imaging II Taras Pokhil , Chairman Determination of Tc , vortex creation and vortex imaging  

E-print Network

and vortex imaging of a superconducting Nb film using low-temperature magnetic force microscopy M. Rosemana: 10.1063/1.1456055 I. INTRODUCTION Magnetic force microscopy is a versatile tool with which to studyMagnetic Microscopy and Imaging II Taras Pokhil , Chairman Determination of Tc , vortex creation

Grütter, Peter

379

Techniques in Solving Anisotropic Eliashberg Gap Equations for the Studies of High Tc Superconductors  

Microsoft Academic Search

Fully solving the anisotropic Eliashberg gap equations is an essential step in seeking the paring information of electrons in anisotropic high Tc superconductors. We report the techniques in solving these equations. The anisotropic gap function Delta( k, omega) and renormalization function Z( k, omega) depend on four dimensional variables, k and omega a regular matrix approach in numerical calculations requires

G. L. Zhao; D. Bagayoko; J. Callaway

1997-01-01

380

Effects of concurrent drug therapy on technetium /sup 99m/Tc gluceptate biodistribution  

SciTech Connect

Drug interactions with /sup 99m/Tc gluceptate resulting in altered biodistribution were studied using chart review and animal tests. Charts of nine patients who had abnormal gallbladder uptake of technetium /sup 99m/Tc gluceptate during a two-year period were reviewed to obtain data such as concurrent drug therapy, primary diagnosis, and laboratory values. Adult New Zealand white rabbits were then used for testing the biodistribution of technetium /sup 99m/Tc gluceptate when administered concurrently with possibly interacting drugs identified in the chart review--penicillamine, penicillin G potassium, penicillin V potassium, acetaminophen, and trimethoprim-sulfamethoxazole. Chart review revealed no conclusive patterns of altered biodistribution associated with other factors. The data did suggest the possibility that the five drugs listed above might cause increased hepatobiliary clearance of the radiopharmaceutical. Animal tests showed that i.v. penicillamine caused substantial distribution of radioactivity into the gallbladder and small bowel. Minimally increased gallbladder radioactivity occurred when oral acetaminophen and trimethoprim-sulfamethoxazole were administered concurrently. Oral and i.v. penicillins did not increase gallbladder activity. Penicillamine may cause substantial alteration of the biodistribution of technetium /sup 99m/Tc gluceptate.

Hinkle, G.H.; Basmadjian, G.P.; Peek, C.; Barker, K.K.; Ice, R.D.

1982-11-01

381

Some Chemical and Structural Effects on the Properties of HIGH-Tc SUPERCONDUCTORS1  

NASA Astrophysics Data System (ADS)

The history of superconductivity, including superconductivity in the high-Tc cuprates, is reviewed very briefly, and the differences between conventional superconductors and the high-Tc cuprates are summarized. The basic crystal structures of the major series of high-Tc cuprates are described and compared. The relation of structures to superconducting properties is reviewed with an emphasis on the orthorhombic-tetragonal transition in (La2-x Srx)CuO4; the corresponding transition, and also the transition to the low-temperature tetragonal phase in (La2-xBax)CuO4; and the effects of oxygen vacancies, oxygen-vacancy ordering, frozen-in disorder, and occupation of the off-chain O(5) sites in YBa2Cu3O7-delta. The effects of chemical substitutions of lanthanide elements on the La/Sr sites in (La2-xSrx)CuO4 and on the Y sites in YBa2Cu3O7-delta, and of 3d elements and sp elements on the Cu sites in both systems are reviewed. The difference between the effects of the lanthanide substitutions, particularly Pr, in the two systems are considered. Major properties of the Bi-, Tl-, and Hg-cuprates, are described briefly. A comparison of the high-Tc cuprates with noncuprate oxide superconductors is given.

Fisher, R. A.; Gordon, J. E.; Phillips, Norman E.

1996-10-01

382

Tc-99m colloid lung uptake in a rare case of toxoplasmosis with liver involvement  

SciTech Connect

Intensive lung accumulation of colloid (Tc-99m phytate) was demonstrated in a child suffering from acquired toxoplasmosis with a rare manifestation of severe liver damage. The possible mechanism and clinical importance of colloid lung concentration in this case is briefly discussed, including a review of the literature on this subject.

Garty, I.; Tal, I.; Kaynan, A.

1984-06-01

383

TagParser: well on the way to ISO-TC37 conformance Gil FRANCOPOULO  

E-print Network

75012 PARIS FRANCE gil.francopoulo@wanadoo.fr Abstract We present rapidly the family of standards (Antoni-Lay), EAGLES, MILE (Bertagna) and TEI reports and we think that the family of specifi- cations-TC37 are not ISO standards yet. Let us recall that to be called "standard", a normative ISO document

Paris-Sud XI, Université de

384

New method for the selective labeling of erythrocytes in whole blood with Tc-99m  

DOEpatents

Method and kit are described for the preparation of /sup 99m/Tc labeled red blood cells using whole blood in a closed sterile system containing stannous tin in a form such that it will enter the red blood cells and be available therein for the reduction of technetium.

Srivastava, S.C.; Babich, J.W.; Straub, R.; Richards, P.

1984-01-27

385

Kit for the selective labeling of red blood cells in whole blood with [sup 99]Tc  

DOEpatents

Disclosed herein are a method and kit for the preparation of [sup 99m]Tc labeled red blood cells using whole blood in a closed sterile system containing stannous tin in a form such that it will enter the red blood cells and be available therein for reduction of technetium. No Drawings

Srivastava, S.C.; Babich, J.W.; Straub, R.; Richards, P.

1992-05-26

386

Kit for the selective labeling of red blood cells in whole blood with .sup.9 TC  

DOEpatents

Disclosed herein are a method and kit for the preparation of .sup.99m Tc labeled red blood cells using whole blood in a closed sterile system containing stannous tin in a form such that it will enter the red blood cells and be available therein for reduction of technetium.

Srivastava, Suresh C. (Setauket, NY); Babich, John W. (Redhill Surrey, GB2); Straub, Rita (Brookhaven, NY); Richards, Powell (New Bern, NC)

1992-01-01

387

Possible explanation of unstable superconducting phase in K xC 60 with Tc=21 K  

NASA Astrophysics Data System (ADS)

EPR and MMMA methods revealed two K 3C 60 phases, the unstable one with Tc=21.0 K containing C 1-60 centers and a stable one with Tc=18.0 K constituting of C 60 molecules in the form of C 3-60 ions. The metastable phase appears only in the first stage of potassium intercalation of fullerene at the C 60/K 3C 60 phase boundary. This phase is being transformed to a stable one on further doping to K 3C 60. The appearance of a metastable phase is related to the instability of the fullerene C 60 fcc structure during the process of octahedral sites being filled by potassium ions. The critical temperature Tc shift upwards from 18.5 to 21.0 K is ascribed to the possible process of potassium transient back charge transfer valency, i.e. K 31+C 603-?K 21+K 1-C 601- [3K 1++C 3-60?2K 1++K 1-+C 601-], which could enlarge the unit cell necessary to shift a superconducting critical temerature according to Tc on volume dependence.

Stankowski, Jan; Luty, Tadeusz; Kempi?ski, Wojciech; Piekara-Sady, Lidia

2001-07-01

388

Iron Arsenides--The New Family of High TC Magnetic Superconductors  

E-print Network

Pdx, Sc1-xUxPd3) · Vortex Lattice/Melting in Superconductors (Nb) · Frustrated Magnets ­ httpIron Arsenides--The New Family of High TC Magnetic Superconductors Jeff Lynn NIST Center Superconductors · (Brief) History of Magnetic Superconductors ­ Magnetic Impurities ­ Long Range Magnetic Order

Weston, Ken

389

High-Tc Superconductivity in Entirely End-bonded Multi-walled nanotubes  

E-print Network

High-Tc Superconductivity in Entirely End-bonded Multi-walled nanotubes Junji Haruyama 1 , Izumi the emergence of superconductivity, such as Tomonaga-Luttinger liquid states and Peierls transition. Carbon nanotubes (CNs) are one of the best candidates for investigating the possibility of 1D superconductivity

Maruyama, Shigeo

390

The effect of average A-site cation radius on TC in perovskite manganites  

NASA Astrophysics Data System (ADS)

Three series of samples Ln 0.7T 0.3MnO 3 (I), Ln 0.7T 0.3Mn 0.9Cr 0.1O 3 (II), and Ln 0.7T 0.3Mn 0.9Fe 0.1O 3 (III) (Ln=La, (La, Nd), (La, Y), T=Ca, CaSr, Sr) were prepared by sol-gel technique. The effect of the average A-site cation radius < rA> on the ferromagnetic transition temperature TC has been investigated. TC was obtained from M- T curves measured by vibrating sample magnetometer. For a little Nd 3+ doped at the A-site, the TC of Ln 0.7T 0.3MnO 3 (I) drops linearly with decreasing < rA> (1.18 Å<< rA><1.25 Å). Similar behavior has been observed in series II and III, which have lower TC values than series I due to the weakening of the influence of double-exchange interactions upon substituting Fe and Cr for Mn.

Wang, Z. M.; Ni, G.; Sang, H.; Du, Y. W.

2001-09-01

391

Effect of ketamine, pentobarbital, and morphine on Tc-99m-DISIDA hepatobiliary kinetics  

SciTech Connect

The purpose of this study was to evaluate hapatobiliary kinetics of Tc-99m-DISIDA in dogs after administration of anesthetic sedative or narcotic agents. Four groups of six male Beagle dogs were studied as a non-treated control group and after parenteral administration of ketamine (30 mg/kg IM), pentobarbital (25 mg/kg IV) or morphine (1 mg/kg IV). Each animal was injected with 4 mCi Tc-99m-DISIDA and hepatobiliary scintigraphic studies were obtained using a gamma camera with parallel hole multipurpose collimator and an A/sup 3/ MDS computer. The authors determined; peak activity of Tc-99m-DISIDA in the liver, visualization and peak activity of gallbladder, and intestinal visualization of Tc-99m-DISIDA. Total bilirubin, LDH, SGOT and SGPT were not modified significantly after any drug compared to control. The results showed that two commonly used anesthetics and sedatives (ketamine and pentobarbital) have dramatic and opposite effects on extrahepatic biliary kinetics. Furthermore, ketamine, but not pentobarbital, significantly accelerates intrahepatic biliary kinetics. Finally, as expected, morphine delayed extrahepatic biliary kinetics. Thus, studies of biliary kinetics should be interpreted with caution when measurements are made after administration of anesthetic, sedative or narcotic agents.

Durakovic, A.; Dubois, A.

1985-05-01

392

Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon  

PubMed Central

Background Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU’s. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil. Methods Blood culture and xenodiagnosis were performed in 36 patients with positive serology for Chagas disease who participated in a serological survey performed in urban and rural areas of Manaus, Amazonas. DNA samples were extracted from the feces of triatomines used for xenodiagnosis, and the nontranscribed spacer of the mini-exon gene and the mitochondrial gene cytochrome oxidase subunit II (COII) were amplified by PCR and sequenced. Results Blood culture and xenodiagnosis were negative in 100% of samples; however, molecular techniques revealed that in 13 out of 36 (36%) fecal samples from xenodiagnosis, T. cruzi was characterized as the DTU TcI, and different haplotypes were identified within the same DTU. Conclusion The DTU TcI, which is mainly associated with acute cases of Chagas disease in the Amazon region, is also responsible for chronic infection in patients from a region in the State of Amazonas. PMID:24916362

2014-01-01

393

Positive curvature of the Hc2-versus-Tc boundaries in layered superconductors  

NASA Technical Reports Server (NTRS)

We have found what we believe to be a universal characteristic of layered superconductors: a positive curvature of the Hc2-versus-Tc boundary. The origins of the effect are believed to be associated with strong anisotropies of the Fermi surface and electron-phonon interaction.

Woollam, J. A.; Somoano, R. B.; O'Connor, P.

1974-01-01

394

RF MEMS for Low-Power Communications Clark T.-C. Nguyen  

E-print Network

RF MEMS for Low-Power Communications Clark T.-C. Nguyen Center for Wireless Integrated Microsystems demonstrations of micro-scale high-Q passive components that utilize microelectromechanical systems (MEMS switches with insertion losses as low as 0.1dB [8]. Although much of the interest in these "RF MEMS

Nguyen, Clark T.-C.

395

Local translation of TC10 is required for membrane expansion during axon outgrowth  

PubMed Central

The surface of developing axons expands in a process mediated by the exocyst complex. The spatial-temporal regulation of the exocyst is only partially understood. Here we report that stimulated membrane enlargement in dorsal root ganglion (DRG) axons is triggered by intra-axonal synthesis of TC10, a small GTPase required for exocyst function. Induced membrane expansion and axon outgrowth are inhibited after axon-specific knockdown of TC10 mRNA. To determine the relationship of intra-axonal TC10 synthesis with the previously described stimulus-induced translation of the cytoskeletal regulator Par3, we investigate the signaling pathways controlling their local translation in response to NGF. Phosphoinositide 3-kinase (PI3K)-dependent activation of the Rheb-mTOR pathway triggers the simultaneous local synthesis of TC10 and Par3. These results reveal the importance of local translation in the control of membrane dynamics and demonstrate that localized, mTOR-dependent protein synthesis triggers the simultaneous activation of parallel pathways. PMID:24667291

Gracias, Neilia G.; Shirkey-Son, Nicole J.; Hengst, Ulrich

2014-01-01

396

Theoretical models of flux pinning and flux motion in high- Tc superconducting oxides  

SciTech Connect

Various issues involved in the development of phenomenological models of flux pinning and motion in high-{Tc} oxides are discussed. A simplified model is presented for the critical current density and is used to examine the question of whether flux flow results from an instability due to plasticity of the flux-line array or from pin breaking.

Welch, D.O.

1991-01-01

397

Theoretical models of flux pinning and flux motion in high-{Tc} superconducting oxides  

SciTech Connect

Various issues involved in the development of phenomenological models of flux pinning and motion in high-{Tc} oxides are discussed. A simplified model is presented for the critical current density and is used to examine the question of whether flux flow results from an instability due to plasticity of the flux-line array or from pin breaking.

Welch, D.O.

1991-12-31

398

Use of Tc-99m glucoheptonate in surgical complications of renal transplant  

SciTech Connect

This study evaluates Tc-99m glucoheptonate for use in renal transplants and finds it detects such surgical complications as urinary extravasation, lymphocele, and postrenal obstruction. The scintigrams were of excellent quality. Functional evaluation of nonsurgical complications was not possible. Whenever both structural and functional information is desired, it may be wise to perform studies with both glucoheptonate and orthoiodohippurate.

Bischoff, P.G.; Washington, J.; Kontzen, F.N.; Dubovsky, E.; Diethelm, A.G.; Whelchel, J.D.; Tauxe, W.N.

1981-03-01

399

Generalized London free energy for high-Tc vortex lattices Ian Affleck  

E-print Network

Generalized London free energy for high-Tc vortex lattices Ian Affleck Department of Physics-1829 97 50402-4 The London free energy provides a very simple way of studying the vortex lattice that this effect can arise from additional quartic derivative terms in the Ginzburg-Landau GL free energy4­7 or

Franz, Marcel

400

Critical currents in Bi-2223 tapes near Tc under magnetic field and ?-irradiation  

NASA Astrophysics Data System (ADS)

The critical temperature and critical current of Bi-2223 tapes have been studied near Tc under a magnetic field and ?-irradiation. Tc decreases from 109 to 96 K with an increase in B up to 100 mT. In the 100-110 K range Ic decreases by about 75-85% at steady rates in low fields up to 20-50 mT, then decreases to zero at slower rates with further increase of field. The Ic versus B plots are non-exponential in small fields (up to 30 mT at 100 K and up to 10 mT at 108 K) and change to exponential form at higher fields and temperatures due to the increased role of flux flow for the current dissipation. The Tc of the tapes decreases from 109 to 106 K with an increase in the ?-dose up to 50 MR, most of the change taking place in low doses up to 10 MR. The critical currents of the tapes decrease by about 50-60% with ?-irradiation under low doses up to 10 MR, then changes very little at higher doses up to 50 MR. We propose that ?-irradiation reduces the anisotropy of the oxygen and carrier distributions in the tapes causing the decrease in Tc and Ic; but the links between the grains, being predominantly SIS-type, have not been effectively changed by ?-irradiation.

Kayed, T. S.; Ozkan, H.; Gasanly, N. M.; Ercan, I.

2000-12-01

401

Trichocystatin-2 (TC-2): an endogenous inhibitor of cysteine proteinases in Trichomonas vaginalis is associated with TvCP39.  

PubMed

The causal agent of trichomoniasis is a parasitic protist, Trichomonas vaginalis, which is rich in proteolytic activity, primarily carried out by cysteine proteases (CPs). Some CPs are known virulence factors. T. vaginalis also possesses three genes encoding endogenous cystatin-like CP inhibitors. The aim of this study was to identify and characterize one of these CP inhibitors. Using two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS), a cystatin-like peptidase inhibitor dubbed Trichocystatin-2 (TC-2) was identified in the T. vaginalis active degradome in association with TvCP39, a 39kDa CP involved in cytotoxicity. To characterize the TC-2 inhibitor, we cloned and expressed the tvicp-2 gene, purified the recombinant protein (TC-2r), and produced a specific polyclonal antibody (?-TC-2r). This antibody recognized a 10kDa protein band by western blotting. An indirect immunofluorescence assay (IFA) and cell fractionation assays using the ?-TC-2r antibody showed that TC-2 was localized in the cytoplasm and lysosomes and that it colocalized with TvCP39. TC-2r showed inhibitory activity against papain, cathepsin-L, and TvCP39 in trichomonad extracts and live parasites but not legumain-like CPs. Live trichomonads treated with TC-2r showed reduced trichomonal cytotoxicity to HeLa cell monolayers in a TC-2r-concentration-dependent manner. In this study, we identified and characterized an endogenous cystatin-like inhibitor in T. vaginalis, TC-2, which is associated with TvCP39 and appears to regulate the cellular damage caused by T. vaginalis. PMID:25200185

Puente-Rivera, Jonathan; Ramón-Luing, Lucero de los Ángeles; Figueroa-Angulo, Elisa Elvira; Ortega-López, Jaime; Arroyo, Rossana

2014-09-01

402

New series of Tc-99m-labeled hepatobiliary tracers: N'-acyl- and N'-sulfonyl ethylenediamine-N,N-diacetic acids  

SciTech Connect

Various Tc-99m-labeled N'-substituted derivatives of ethylenediamine-N,N-diacetic acid (EDDA) are evaluated as hepatobiliary imaging agents. N'-substituted aromatic acyl and aromatic sulfonyl derivatives of EDDA, labeled with Tc-99m, were administered to rabbits and golden hamsters, and the distribution indicated clearance by the hepatobiliary system. N'-aromatic sulfonyl EDDAs were labeled with Tc-99m by the SnCl/sub 2/ method with more than 99% yield. Clearance of Tc-99m-p-toluenesulfonyl EDDA from the blood and the liver was as rapid as that of Tc-99m N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid (Tc-99m diethyl IDA). Substitution of a bulky group at the aromatic ring in Tc-99m benzene-sulfonyl EDDA lowered urinary excretion. It is concluded that the sulfonyl EDDAs provide a fruitful source for Tc-99m-labeled hepatobiliary radiopharmaceuticals.

Karube, Y.; Kono, A.; Maeda, T.; Ohya, M.; Matsushima, Y.

1981-07-01

403

Injection site radioactivity of (99m)tc-labeled mannosylated dextran for sentinel lymph node mapping.  

PubMed

The high and persistent radioactivity at the injection site hinders the accuracy and expansion of sentinel lymph node (SLN) mapping. We investigated the mechanism underlying the undesirable radioactivity after subcutaneous injection of (99m)Tc-labeled mannosylated dextran ((99m)Tc(CO)3-DCM20), a SLN mapping agent targeting mannose receptors on macrophages and dendritic cells, in a mouse model. Biodistribution studies were performed 1 h after subcutaneous injection of (99m)Tc(CO)3-DCM20 from the rear footpad of mice in the presence of varying molar amounts of DCM20 or DC15, a modified dextran without mannose. Biodistribution studies were also conducted after subcutaneous injection of [(125)I]radioiodinated mannosyl-neoglycoalbumin ((125)I-NMA) from the rear footpad. The distribution of fluorescence-labeled DCM20 and DC15 at the injection site was also compared 1 h after subcutaneous injection by immunofluorescent histochemistry. The radioactivity levels of (99m)Tc(CO)3-DCM20 at the injection site and popliteal lymph node, a SLN in this model, decreased with an increase in the molar amounts of DCM20, whereas no significant changes in biodistribution were observed after injection of (99m)Tc(CO)3-DCM20 with varying molar amounts of DC15. (125)I-NMA exhibited rapid elimination of radioactivity from both the popliteal lymph node and the injection site. The fluorescence-labeled DCM20 colocalized well with CD68-positive cells such as macrophages and dendritic cells at the injection site. While partial colocalization was observed between DC15 and CD68-positive cells, the signal intensity was very weak. These findings suggest that specific binding of (99m)Tc(CO)3-DCM20 to the mannose receptor on macrophages and dendritic cells would be responsible for the sustained radioactivity levels at the injection site. These results also imply that discriminated blockage of (99m)Tc(CO)3-DCM20 binding to mannose receptors at the injection sites would reduce the radioactivity at the injection site. PMID:25423619

Yamaguchi, Aiko; Hanaoka, Hirofumi; Pirmettis, Ioannis; Uehara, Tomoya; Tsushima, Yoshito; Papadopoulos, Minas; Arano, Yasushi

2015-02-01

404

{sup 99}Tc bioassay by inductively coupled plasma mass spectrometry (ICP-MS)  

SciTech Connect

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 scintillation or gas flow proportional counting. In a urine matrix, the analysis of{sup 99}Tc is plagued with many difficulties using conventional radiometric methods. Difficulties originate during chemical separation due to the volatile nature of Tc{sub 2}O{sub 7} or during radiation detection due to color or chemical quenching. A separation scheme for {sup 99}Tc detection by ICP-MS is given and is proven to be a sensitive and robust analytical alternative. A comparison of methods using radiometric and mass quantitation of {sup 99}Tc has been conducted in water, artificial urine, and real urine matrices at activity levels between 700 and 2,200 dpm/L. Liquid scintillation results based on an external standard quench correction and a quench curve correction method are compared to results obtained by ICP-MS. Each method produced accurate results, however the precision of the ICP-MS results is superior to that of liquid scintillation results. Limits of detection (LOD) for ICP-MS and liquid scintillation detection are 14.67 and 203.4 dpm/L, respectively, in a real urine matrix. In order to determine the basis for the increased precision of the ICP-MS results, the detection sensitivity for each method is derived and measured. The detection sensitivity for the {sup 99}Tc isotope by ICP-MS is 2.175 x 10{sup {minus}7} {+-} 8.990 x 10{sup {minus}9} and by liquid scintillation is 7.434 x 10{sup {minus}14} {+-} 7.461 x 10{sup {minus}15}. A difference by seven orders of magnitude between the two detection systems allows ICP-MS samples to be analyzed for a period of 15 s compared to 3,600 s by liquid scintillation counting with a lower LOD.

Lewis, L.A.

1998-05-01

405

Physical phantom evaluation of simultaneous 99mTc/ 123I SPECT imaging  

NASA Astrophysics Data System (ADS)

Simultaneous dual-isotope imaging from two different energy gamma rays such as 99mTc and 123I is a promising technology in nuclear medicine. Its advantages are to abbreviate the acquisition procedure with an identical geometrical registration of the different isotope images, the same physiological condition without motion artifacts, and help patient throughput and comfort. However, the energy photopeaks of 99mTc and 123I radionuclides are very close. We had developed a new approach for accurate cross-talk and scatter corrections in simultaneous 99mTc/ 123I based on independent components analysis (ICA). Nevertheless, a large number of input energy windows are required as ICA input components, which is not useful in clinical application because commercial cameras have only 3-8 energy windows. The aim of this work was to design a new method through wavelet transformation followed by ICA with multiple energy windows (W_eICA) for cross-talk and scatter correction using a smaller number of energy windows in clinical use. There were three cylinders (A-C) with identical volume of 20 ml. Cylinder A was filled with 99mTc solution of 18.5 MBq, cylinder B with 123I solution of 18.5 MBq, and cylinder C with 99mTc solution of 55.5 MBq. The Image matrix size was 128×128 and pixel size was 3.9 mm. Three kinds of images were acquired by energy window setting. (1) For single-isotope imaging only, energy windows of 20% centered at 140 keV for 99mTc and at 159 keV for 123I were used. (2) In the asymmetric energy window method (AEW), energy window of 15% centered at 140 keV for 99mTc in conjunction with 10% asymmetric energy window in an upper bound at 159 keV for 123I was acquired. (3) Then we set six energy windows with 15 keV width ranging from 83 to 173 keV to form six images as input components of ICA. After the W_eICA method derived 99mTc/ 123I images alone, we compared the images from the W_eICA approach and the AEW method. In the results, the recovery rate of 99mTc was 1.03 and that of 123I was 1.07 from the W_eICA method. Besides, the recovery rate of 99mTc was 0.84 and that of 123I was 1.05 from the AEW approach. According to our results, the W_eICA method not only decreased the number of energy windows but also separated dual-isotope photopeaks successfully. The results have demonstrated that the W_eICA method improved the quantitative accuracy and might be an effective tool for simultaneous dual-isotope SPECT imaging.

Yang, Bang-Hung; Wang, Shyh-Jen; Lee, Jhih-Shian; Jan, Meei-Ling; Chang, Chia-Jung; Chen, Jyh-Cheng

2011-10-01

406

Challenges to high-Tc superconductivity in cuprates by exploring condensate properties  

NASA Astrophysics Data System (ADS)

In this paper, I introduce recent our results on superconductivity fluctuation measurement of high-Tc cuprate both for the hole-doped La2-xSrxCuO4 (LSCO) and the electron-doped La2-xCexCuO4 (LCCO). In hole doped LSCO, the universality class was found to change twice as a function of doping, starting from the 2D-XY, changing to the 3D XY and another 2D 'unknown' behavior. The results favors theoretical interpretations of the phase diagram of high-Tc cuprate which assume the existence of an additional hidden quantum critical point around at the optimum doping. In electron doped cuprate, the superconductivity fluctuation is 3D XY for all samples with different hole doping, which is in sharp contrast to the hole doped cuprate. Thus, the asymmetry of the phase diagram between the hole doped and the electron doped materials is another important key factor to judge the applicability of various theories on high-Tc superconductivity. Under finite magnetic fields, the scaling relation was valid only for weak fields, and for higher fields, aspects as vortices appeared. However, even at low temperatures, just above the first order phase transition, vortex picture alone cannot describe the data satisfactory. Thus, we need a unified theory for the description of a large superconductivity fluctuation under finite magnetic fields for high-Tc cuprates. Finally, I showed that our novel technique of fabricating high-Tc Josephson bridge junction using a small island of Fe was turned out to be very promising.

Maeda, A.

2008-03-01

407

High-field ?SR studies of superconducting and magnetic correlations in cuprates above T(c).  

PubMed

The advent of high transverse field muon spin rotation (TF-?SR) has led to recent ?SR investigations of the magnetic field response of cuprates above the superconducting transition temperature T(c). Here the results of such experiments on hole-doped cuprates are reviewed. Although these investigations are currently ongoing, it is clear that the effects of high field on the internal magnetic field distribution of these materials is dependent upon competition between superconductivity and magnetism. In La(2 - x)Sr(x)CuO(4) the response to the external field above T(c) is dominated by heterogeneous spin magnetism. However, the magnetism that dominates the observed inhomogeneous line broadening below x ? 0.19 is overwhelmed by the emergence of a completely different kind of magnetism in the heavily overdoped regime. The origin of the magnetism above x ? 0.19 is probably related to intrinsic disorder, but the systematic evolution of the magnetism with doping changes in the doping range beyond the superconducting 'dome'. In contrast, the width of the internal field distribution of underdoped Y Ba(2)Cu(3)O(y) above T(c) is observed to track T(c) and the density of superconducting carriers. This observation suggests that the magnetic response above T(c) is not dominated by electronic moments, but rather inhomogeneous fluctuating superconductivity. The spatially inhomogeneous response of Y Ba(2)Cu(3)O(y) to the applied field may be a means of minimizing energy, rather than being caused by intrinsic disorder. PMID:21393701

Sonier, J E

2010-05-26

408

Rapid diagnosis of occult abscesses using sup 99m Tc-labeled monoclonal antibodies  

SciTech Connect

Acute infections, such as appendicitis and occult infections in AIDS patients, can be diagnosed within two hours by gamma scintigraphy after i.v. administration of {sup 99m}Tc labeled antibodies reactive with human granulocytes. The antibody, murine IgM anti-SSEA-1, is partially reduced using Sn(II) to expose and protect reactive sulfide groups. The antibody is then purified, stannous tartrate and stabilizers are added, and the mixture is lyophilized. To label, sodium pertechnetate is added. After a 15 minute incubation the tracer drug is injected. The rate of accumulation and degree of concentration at the site of infection is presumptively determinative of the severity of the infection. Acceptance criteria and tests for the {sup 99m}Tc labeled antibody product have been established and validated. Greater than 93% of the {sup 99m}Tc is firmly bound to the protein as determined by quantitative HPLC. Radiochemical impurities, colloidal {sup 99m}Tc and free pertechnetate are together less than 4% as determined by thin layer chromatography. The immunoreactive fraction, measured by binding to solid phase antigen, and affinity measured be ELISA, are unchanged by the {sup 99m}Tc-direct labeling process. Two hour blood clearance in rats is within 90% of the value of the {sup 125}I labeled analog. The immunoreactive fraction decreases less than 10% when incubated in human plasma for 24 hours. This method has been compared to other direct labeling methods, and found to give higher radiochemical yields. 5 figs.

Coons, T.A.; Rhodes, B.A. (RhoMed, Inc., Albuquerque, NM (USA)); Thakur, M.L. (Thomas Jefferson Univ., Philadelphia, PA (USA)); Marcus, C.S. (Harbor-UCLA Medical Center, Torrance, CA (USA)); Ballou, B. (Pittsburgh Univ., PA (USA))

1991-01-01

409

Successful Labeling of \\text{99mTc-MDP Using \\text{99mTc Separated from 99Mo Produced by 100Mo(n,2n)99Mo  

NASA Astrophysics Data System (ADS)

We have for the first time succeeded in separating \\text{99mTc from a MoO3 sample irradiated with accelerator neutrons free from any radioactive impurities and in formulating \\text{99mTc-methylene diphosphonate (\\text{99mTc-MDP). 99Mo, the mother nuclide of \\text{99mTc, was produced by the 100Mo(n,2n)99Mo reaction using about 14 MeV neutrons provided by the 3H(d,n)4He reaction at the Fusion Neutronics Source of Japan Atomic Energy Agency. The \\text{99mTc was separated from 99Mo by sublimation and its radionuclide purity was confirmed to be higher than 99.99% by ?-spectroscopy. The labeling efficiency of \\text{99mTc-MDP was shown to be higher than 99% by thin-layer chromatography. These values exceed the United States Pharmacopeia requirements for a fission product, 99Mo. Consequently, a \\text{99mTc radiopharmaceutical preparation formed by using the mentioned 99Mo can be a promising substitute for the fission product 99Mo, which is currently produced using a highly enriched uranium target in aging research reactors. A longstanding problem to ensure a reliable and constant supply of 99Mo in Japan can be partially mitigated.

Nagai, Yasuki; Hatsukawa, Yuichi; Kin, Tadahiro; Hashimoto, Kazuyuki; Motoishi, Shoji; Konno, Chikara; Ochiai, Kentaro; Takakura, Kosuke; Sato, Yuichi; Kawauchi, Yukimasa; Sato, Norihito; Ohta, Akio; Yamabayashi, Hisamichi; Tanase, Masakazu; Fujisaki, Saburo; Teranaka, Tomoyuki; Takeuchi, Nobuhiro; Igarashi, Takashi

2011-08-01

410

Transport critical current measurement apparatus using liquid nitrogen cooled high-Tc superconducting magnet with variable temperature insert  

NASA Astrophysics Data System (ADS)

We have developed an apparatus to investigate transport critical current (Ic) as a function of magnetic field and temperature using only liquid nitrogen. The apparatus consists of a (Bi,Pb)2Sr2Ca2Cu3O10 (Bi-2223) superconducting magnet, an outer dewar, and a variable temperature insert (VTI). The magnet, which is operated in depressurized liquid nitrogen, generates magnetic field up to 1.26 T. The sample is also immersed in liquid nitrogen. The pressure in the VTI is controlled from 0.02 to 0.3 MPa, which corresponds to temperature ranging from 66 to 88 K. We have confirmed the long-term stable operation of the Bi-2223 magnet at 1 T. The temperature stability of the sample at high transport current was also demonstrated. The apparatus provides easy-operating Ic measurement environment for a high-Tc superconductor up to 500 A in magnetic fields up to 1 T and in temperatures ranging from 66 to 88 K.

Nishijima, G.; Kitaguchi, H.; Tshuchiya, Y.; Nishimura, T.; Kato, T.

2013-01-01

411

Comparison of 99mTc-3PRGD2 Integrin Receptor Imaging with 99mTc-MDP Bone Scan in Diagnosis of Bone Metastasis in Patients with Lung Cancer: A Multicenter Study  

PubMed Central

Purpose 99mTc-3PRGD2, a promising tracer targeting integrin receptor, may serve as a novel tumor-specific agent for single photon emission computed tomography (SPECT). A multi-center study was prospectively designed to evaluate the diagnostic accuracy of 99mTc-3PRGD2 imaging for bone metastasis in patients with lung cancer in comparison with the conventional 99mTc-MDP bone scan. Methods The patients underwent whole-body scan and chest tomography successively at both 1 h and 4 h after intravenous injection of 11.1 MBq/Kg 99mTc-3PRGD2. 99mTc-MDP whole-body bone scan was routinely performed within 1 week for comparison. Three experienced nuclear medicine physicians blindly read the 99mTc-3PRGD2 and 99mTc-MDP images. The final diagnosis was established based on the comprehensive assessment of all available data. Results A total of 44 patients (29 male, 59±10 years old) with suspected lung cancer were recruited from 4 centers. Eighty-nine bone lesions in 18 patients were diagnosed as metastases and 23 bone lesions in 9 patients were benign. In a lesion-based analysis, 99mTc-3PRGD2 imaging demonstrated a sensitivity, specificity, and accuracy of 92.1%, 91.3%, and 92.0%, respectively. The corresponding diagnostic values for 99mTc-MDP bone scan were 87.6%, 60.9%, and 82.1%, respectively in the same patients. 99mTc-MDP bone scan had better contrast in most lesions, whereas the 99mTc-3PRGD2 imaging seemed to be more effective to exclude pseudo-positive lesions and detect bone metastases without osteogenesis. Conclusion 99mTc-3PRGD2 is a novel tumor-specific agent based on SPECT technology with a promising value in diagnosis of bone metastasis in patients with lung cancer. Trial Registration ClinicalTrials.gov NCT01737112 PMID:25338281

Miao, Weibing; Zheng, Shan; Dai, Haojie; Wang, Feng; Jin, Xiaona; Zhu, Zhaohui; Jia, Bing

2014-01-01

412

Trypanosoma cruzi TcSMUG L-surface Mucins Promote Development and Infectivity in the Triatomine Vector Rhodnius prolixus  

PubMed Central

Background TcSMUG L products were recently identified as novel mucin-type glycoconjugates restricted to the surface of insect-dwelling epimastigote forms of Trypanosoma cruzi, the etiological agent of Chagas disease. The remarkable conservation of their predicted mature N-terminal region, which is exposed to the extracellular milieu, suggests that TcSMUG L products may be involved in structural and/or functional aspects of the interaction with the insect vector. Methodology and Principal Findings Here, we investigated the putative roles of TcSMUG L mucins in both in vivo development and ex vivo attachment of epimastigotes to the luminal surface of the digestive tract of Rhodnius prolixus. Our results indicate that the exogenous addition of TcSMUG L N-terminal peptide, but not control T. cruzi mucin peptides, to the infected bloodmeal inhibited the development of parasites in R. prolixus in a dose-dependent manner. Pre-incubation of insect midguts with the TcSMUG L peptide impaired the ex vivo attachment of epimastigotes to the luminal surface epithelium, likely by competing out TcSMUG L binding sites on the luminal surface of the posterior midgut, as revealed by fluorescence microscopy. Conclusion and Significance Together, these observations indicate that TcSMUG L mucins are a determinant of both adhesion of T. cruzi epimastigotes to the posterior midgut epithelial cells of the triatomine, and the infection of the insect vector, R. prolixus. PMID:24244781

Gonzalez, Marcelo S.; Souza, Marcela S.; Garcia, Eloi S.; Nogueira, Nadir F. S.; Mello, Cícero B.; Cánepa, Gaspar E.; Bertotti, Santiago; Durante, Ignacio M.; Azambuja, Patrícia; Buscaglia, Carlos A.

2013-01-01

413

The GTPase TcRjl of the human pathogen Trypanosoma cruzi is involved in the cell growth and differentiation.  

PubMed

The protozoan parasite Trypanosoma cruzi, the etiological agent of Chagas Disease, undergoes through a complex life cycle where rounds of cell division and differentiation occur initially in the gut of triatominae vectors and, after transmission, inside of infected cells in vertebrate hosts. Members of the Ras superfamily of GTPases are molecular switches which play pivotal regulatory functions in cell growth and differentiation. We have previously described a novel GTPase in T. cruzi, TcRjl, which belongs to the RJL family of Ras-related GTP binding proteins. Here we show that most of TcRjl protein is found bound to GTP nucleotides and may be locked in this stage. In addition, we show that TcRjl is located close to the kinetoplast, in a region corresponding possibly to flagellar pocket of the parasite and the expression of a dominant-negative TcRjl construct (TcRjlS37N) displays a significative growth phenotype in reduced serum medium. Remarkably, overexpression of TcRjl inhibits differentiation of epimastigotes to trypomastigote forms and promotes the accumulation of intermediate differentiation stages. Our data suggest that TcRjl might play a role in the control of the parasite growth and differentiation. PMID:22326867

dos Santos, Guilherme Rodrigo Reis Monteiro; Nepomuceno-Silva, José Luciano; de Melo, Luiz Dione Barbosa; Meyer-Fernandes, José Roberto; Salmon, Didier; Azevedo-Pereira, Ricardo Luiz; Lopes, Ulisses Gazos

2012-03-01

414

99mTc-labeling of a hydrazinonicotinamide-conjugated vitronectin receptor antagonist useful for imaging tumors.  

PubMed

This report describes the (99m)Tc labeling of a HYNIC-conjugated vitronectin receptor antagonist (SQ168 = [2-[[[5-[carboonyl]-2-pyridinyl]hydrazono]methyl]benzenesulfonic acid]-Glu(cyclo[Lys-Arg-Gly-Asp-D-Phe])-cyclo[Lys-Arg-Gly-Asp-D-Phe]). The ternary ligand complex [(99m)Tc(SQ168)(tricine)(TPPTS)] (RP593) was prepared using a non-SnCl(2)-containing formulation. The corresponding (99)Tc analogue, [(99)Tc]RP593, was also prepared and characterized by HPLC and LC-MS. A HPLC concordance experiment using RP593 and [(99)Tc]RP593 showed that the same technetium complex was prepared at both the tracer and macroscopic levels. The LC-MS data is completely consistent with the 1:1:1:1 composition for Tc:SQ168:tricine:TPPTS and provides direct evidence that the two radiometric peaks in the radio-HPLC chromatogram of RP593 are indeed due to the resolution of diastereomers. In an in vitro receptor binding assay, [(99)Tc]RP593 was shown to have comparable binding affinity for the vitronectin receptor to that of SQ168 itself. PMID:11459468

Liu, S; Edwards, D S; Ziegler, M C; Harris, A R; Hemingway, S J; Barrett, J A

2001-01-01

415

Products of pertechnetate radiolysis in highly alkaline solution: structure of TcO2 x xH2O.  

PubMed

The chemistry of technetium in certain high-level nuclear waste (HLW) tanks at the Hanford Site complicates the treatment and vitrification of HLW. A major problem is the presence, in certain tanks, of unidentified, lower-valent technetium species, which are difficult to remove from the waste by current separation processes. Radiolytic reduction of TcO4- in alkaline solutions containing selected organic compounds, approximating the conditions in HLW, was investigated to determine the classes of compounds that can be formed under these conditions. Insoluble TcO2 x xH2O is the primary radiolysis product with the majority of organic compounds investigated, including citrate, dibutyl phosphate, and aminopolycarboxylates. X-ray absorption fine structure (XAFS) measurements show that TcO2 x xH2O has a one-dimensional chain structure consisting of edge-sharing TcO6 octahedra with bridging oxide and trans water ligands. When diols, such as ethylene glycol, are present, only soluble, Tc(IV) alkoxide compounds are produced. The XAFS and UV-visible spectra of these compounds provide evidence for a binuclear structure similar to (H2EDTA)2Tc2(mu-O)2. The properties of the Tc(IV) alkoxide complexes were determined and are consistent with those observed for the soluble, lower-valent technetium complexes that complicate the treatment of HLW at the Hanford site. PMID:11918000

Lukens, Wayne W; Bucher, Jerome I; Edelstein, Norman M; Shuh, David K

2002-03-01

416

Genetic Characterization of Trypanosoma cruzi DTUs in Wild Triatoma infestans from Bolivia: Predominance of TcI  

PubMed Central

Background The current persistence of Triatoma infestans (one of the main vectors of Chagas disease) in some domestic areas could be related to re-colonization by wild populations which are increasingly reported. However, the infection rate and the genetic characterization of the Trypanosoma cruzi strains infecting these populations are very limited. Methodology/Principal Findings Of 333 wild Triatoma infestans specimens collected from north to south of a Chagas disease endemic area in Bolivia, we characterized 234 stocks of Trypanosoma cruzi using mini-exon multiplex PCR (MMPCR) and sequencing the glucose phosphate isomerase (Gpi) gene. Of the six genetic lineages (“discrete typing units”; DTU) (TcI-VI) presently recognized in T. cruzi, TcI (99.1%) was overdominant on TcIII (0.9%) in wild Andean T. infestans, which presented a 71.7% infection rate as evaluated by microscopy. In the lowlands (Bolivian Chaco), 17 “dark morph” T. infestans were analyzed. None of them were positive for parasites after microscopic examination, although one TcI stock and one TcII stock were identified using MMPCR and sequencing. Conclusions/Significance By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles. PMID:22685616

Brenière, Simone Frédérique; Aliaga, Claudia; Waleckx, Etienne; Buitrago, Rosio; Salas, Renata; Barnabé, Christian; Tibayrenc, Michel; Noireau, François

2012-01-01

417

Environmental applications of XANES: Speciation of {Tc} in cement after chemical treatment and Se after bacterial uptake  

SciTech Connect

XANES (X-ray Absorption Near Edge Spectroscopy) has been employed to evaluate the efficacy of a process designed to encapsulate and reduce {Tc}O{sub 4}{sup {minus}} in cement matrices, thereby immobilizing {Tc}. The oxidation state of Se following.bioremediation of Se by bacteria has also been determined by XANES. The XANES measurements were performed at the Stanford Synchrotron Radiation Laboratory (SSRL) and the National Synchrotron Light Source (NSLS) at the respective K edges of {Tc} (21.0 keV) and Se (12.7 keV). Comparison of the XANES spectra of Tc in untreated cement to Tc in slag treated cement and to the chemical shifts of reference materials, shows that the oxidation state of {Tc} is the same in both cements. Thus, the addition of a reducing agent to the cement formulation does not significantly reduce the {Tc}O{sub 4} The common soil bacterium, Bacillus subtilis, is known to incorporate Se on or within the cell wall when exposed to a SE(IV) solution. The Se XANES spectra of B. subtilis, as well as bacillus isolated from selenium rich soil, show that the organisms reduce selenite to the red allotrope of elemental Se.

Shuh, D.K.; Kaltsoyannis, N.; Bucher, J.J. [and others

1994-03-01

418

Automatic and simple method for ??Tc determination using a selective resin and liquid scintillation detection applied to urine samples.  

PubMed

(99m)Tc (6.0067 h half-life) is an artificial radionuclide largely used in diagnostic medicine. Its daughter (99)Tc is a beta emitter of great concern because of its long half-life (2.111 × 10(5) years) and presumed mobile behavior in the environment. To monitor the (99)Tc in urine from treated patients, an automatic Lab-on-valve (LOV) system for separation and preconcentration of (99)Tc was developed. TEVA resin was selected since it retains pertechnetate ion selectively from diluted nitric acid solutions. After elution, (99)Tc is detected using a liquid scintillation counting (LSC) detector. The present method has been successfully applied to urine samples with low (99)Tc content (recoveries between 94-111%). The minimum detectable activity (MDA) of the developed method is 0.1 Bq or 1 Bq L(-1) (expressed as activity concentration), when preconcentrating 100 mL of sample. The high durability of the resin, together with the low amount of resin required (32 mg), the good reproducibility (RSD 2%, n = 5) and the high extraction frequency (up to 12 h(-1)) makes of the present method an inexpensive, precise and fast useful tool for monitoring (99)Tc in urine samples. PMID:23683144

Villar, Marina; Avivar, Jessica; Ferrer, Laura; Galmés, Margalida; Vega, Fernando; Cerda, Víctor

2013-06-01

419

Anger camera image generation with microcomputers  

E-print Network

n g 8 o r h the m i c r o c o rr p u t e r s n 8 t1. e i n t e r a c e b o a r d was 2 sof. tware system. It generated images o:) the microcomputer m"nitor, controlled the movement of data, and was able tc, extract data from an image series... and Data 112 hPPENDIX F NED-IV Acquired Image and Data Page 115 Vi APPENI'&IX G /(CT I. an(. l giiiD ? I V;(cqu i r(. d I m; 6(. a go rm:& I I. un 8 Scan . 118 API'EIID IX 8 ACTI and IIED ? IV Acquired Imag(. e Abnora&aI Lur. g Scan 121 APPEIIDIX...

Williams, Karl Morgan

2012-06-07

420

Coligand Effects on Solution Stability, Biodistribution and Metabolism of 99mTc-Labeled Cyclic RGDfK Tetramer  

PubMed Central

In this study, we present the evaluation of two new ternary ligand 99mTc complexes [99mTc(HYNIC-tetramer)(tricine)(L)] (L = ISONIC and PDA) as potential radiotracers for tumor imaging. The athymic nude mice bearing the MDA-MB-435 human breast cancer xenografts were used to evaluate their biodistribution and metabolic properties. The solution stability data showed that [99mTc(HYNIC-tetramer)(tricine)(L)] (L = ISONIC and PDA) had a significant (14% and 35%, respectively) at 6 h in the absence of excess ISONIC or PDA coligand. Biodistribution data clearly showed that [99mTc(HYNIC-tetramer)(tricine)(PDA)] has much lower uptake in most organs of interest than [99mTc(HYNIC-tetramer)(tricine)(ISONIC)] during the 2 h study period. Results from metabolism studies revealed that ~50% of [99mTc(HYNIC-tetramer)(tricine)(ISONIC)] remained intact in feces samples at 120 min p.i. Only 10% of [99mTc(HYNIC-tetramer)(tricine)(PDA)] remained intact in feces samples. The extent of metabolism correlates well with the radiotracer solution stability. The results from this and our previous studies clearly demonstrated that coligands (TPPTS, ISONIC and PDA) have a significant impact on tumor uptake, excretion kinetics and metabolism of the 99mTc-labeled cyclic RGDfK tetramer. Among the three radiotracers evaluated in this tumor-bearing animal model, [99mTc(HYNIC-tetramer)(tricine)(TPPTS)] remains the best with respect to blood clearance, tumor uptake, target/background ratios. PMID:18158950

Liu, Shuang; Kim, Young-Seung; Hsieh, Wen-Yuan; Sreerama, Subramanya Gupta

2008-01-01