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1

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

PubMed

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

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

2012-01-01

2

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

3

Fission 99Mo/99mTc Generators--a study of their quality.  

PubMed

Quality was controlled of seven different 99Mo/99mTc generators sold in the Federal Republic of Germany, which were all loaded with fission molybdenum. Aim of the work was to test the 99mTc eluates for their radionuclidic and radiochemical purity. Furthermore, the 99Mo content of the aluminium oxide column was measured. Determination of the elution efficiency, measurement of the pH-value of the eluate as well as a test to detect soluble aluminium in the eluate were also performed. In addition to the chemical and physical examinations, application, quality of accessories and their practicability were tested at all generators. The methods of analysis chosen were, among others, gamma spectrometry and thin-layer chromatography; the measuring methods were a site-sensitive proportional counter (measurement of the distribution of radioactivity of the chromatograms) and atomic absorption spectrometry (Al content of the eluates). The quality control of the 99mTc eluates had satisfying results. The eluates showed - with one exception - high and sufficient radionuclidic purity and very good radiochemical purity. A considerable overload of the columns with 99Mo at the time of reference was not found. The elution yields with values between 85 and 122% were in good agreement with the requirements. All eluates had pH-values between 5.0 and 6.5, and an aluminium content below 1 microgram/ml. The generators had good performance and proved generally to be a reliable source of 99mTc-pertechnetate. The application was safe and, with some exceptions, fulfilled the requirements. PMID:2813084

Reich, E; Bögl, K W

1989-10-01

4

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

5

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

DOEpatents

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

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

1998-01-01

6

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

DOEpatents

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

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

1998-09-01

7

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

Microsoft Academic Search

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

T. Braun; H. Imura; N. Suzuki

1987-01-01

8

Microwave transmission and harmonic generation in granular high-Tc superconducting films: Evidence for viscous flux motion and weak links  

Microsoft Academic Search

We have studied the microwave transmission tau through thin superconducting films of Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O in the presence of a dc magnetic field H0 and an alternating magnetic field, H1cos2pif0t. The alternating field generates many harmonics due to the nonlinear response of the complex resistivity. The microwave transmission with H0 in the plane of the film depends on the orientation

M. Golosovsky; D. Davidov; E. Farber; T. Tsach; M. Schieber

1991-01-01

9

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

10

{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

11

Nanoparticulas basadas en complejos de Fe(II) con transicion de espin: sintesis, caracterizacion y aplicaciones en electronica molecular  

NASA Astrophysics Data System (ADS)

Esta tesis doctoral esta organizada en 5 capitulos y esta destinada al estudio de sistemas de Fe (II) que presentan el fenomeno de la transicion de espin a escala nanometrica. El capitulo 1 contiene una introduccion general sobre materiales moleculares multifuncionales, destacando aquellos ejemplos mas importantes. Por otro lado, se explicara el fenomeno de la transicion de espin, tratando aspectos conceptuales, los antecedentes mas importantes y la situacion actual. En el capitulo 2 se describen los diferentes procesos existentes para la obtencion de diferentes tipos de nanoparticulas. Ademas, se presenta la sintesis y caracterizacion de nanoparticulas del polimero de coordinacion unidimensional [Fe(Htrz)2(trz)]BF4, obtenidas mediante el metodo de micelas inversas. Estas nanoparticulas, con una estrecha distribucion de tamanos centrada alrededor de los 11 nm, presentan una transicion de espin muy abrupta, con un ancho ciclo de histeresis termica de unos 40K. En el capitulo 3 se describe el proceso de modificacion del tamano de las nanoparticulas descritas en el capitulo anterior, llevado a cabo variando la proporcion de surfactante/H2O en el medio. Ademas, con el objetivo de modificar las propiedades magneticas de las nanoparticulas obtenidas en el capitulo 2, se lleva a cabo la sintesis de nanoparticulas de polimeros de la misma familia del [Fe(Htrz)2(trz)]BF4. En concreto se sintetizaron 3 nuevos tipos de nanoparticulas basadas en el polimero [Fe(Htrz)1-x(NH2trz)x](ClO4)2, siendo x = 0.05, 0.15 y 0.3, en cada caso. Estas nanoparticulas siguen presentando una estrecha distribucion de tamanos y una transicion de espin muy abrupta y con un ancho ciclo de histeresis. Ademas, se observa que este ciclo se desplaza a temperaturas mas proximas a la temperatura ambiente a medida que se aumenta el porcentaje de 4-amino-1, 2, 4- triazol en la muestra. Pero al mismo tiempo se produce una disminucion de la anchura de este ciclo. Por ultimo, en este capitulo se presenta la sintesis de otro nuevo tipo de nanoparticulas, obtenidas a partir de otro polimero de la misma familia, el [FeO8ZnO2(Htrz)3](BF4). Estas nanoparticulas se sintetizaron con el objetivo de estudiar el efecto de la dilucion del metal en la muestra. Como resultado se obtuvieron nanoparticulas que tambien presentan una estrecha distribucion de tamanos pero en este caso la transicion de espin no es tan abrupta como en los casos anteriores. Aunque sigue presentando un ciclo de histeresis termica bastante ancho y a temperaturas proximas a la temperatura ambiente. En el capitulo 4 se describiran las estrategias que se han seguido para mejorar la estabilidad y afinidad sobre diferentes sustratos de las nanoparticulas sintetizadas en el capitulo 2. Tambien se hablara de los intentos realizados parar depositarlas en superficies y embeberlas en diferentes matrices organicas e inorganicas. En el capitulo 5 presentaremos la obtencion de un interruptor molecular realizado poniendo en contacto nanoparticulas individuales sintetizadas en el capitulo 2, con unos electrodos separados varios nanometros. Este dispositivo exhibe "switching" y efecto memoria a temperaturas proximas a la temperatura ambiente como consecuencia de la biestabilidad intrinseca de las nanoparticulas. Ademas demostraremos que el estado magnetico de estas nanoparticulas puede ser controlado electricamente, ya que la transicion de espin en este nanodispositivo molecular puede ser inducida simplemente aplicando un voltaje, lo que puede ser de gran interes para la electronica molecular.

Monrabal Capilla, Maria

12

Anticancer Tc9 cells  

PubMed Central

IL-9-producing cytotoxic T (Tc9) cells represent a unique CD8+ T-cell subset. These long-lived immune cells possess the capacity to acquire effector function and home to tumor tissues after adoptive transfer. IL-9 is indispensable for Tc9-mediated superior antitumor response. These findings are highly significant and crucial to achieve advances in T cell-based adoptive therapies. PMID:25054087

Lu, Yong; Wang, Qiang; Yi, Qing

2014-01-01

13

TC42/WG18 98 -______ TC130/WG3 98 -______  

E-print Network

sensitivity based characterisation................................. 12 5.2 Method B: standard ISO DSC colour-2-1......................................................................................... 28 Annexes A Standard ISO DSC colour target specifications (NormativeTC42/WG18 98 - ______ TC130/WG3 98 - ______ ISO/TC42 Photography WG18 Electronic Still Picture

Drew, Mark S.

14

Die beta-Zerfallsenergie der Technetiumisotope Tc103, Tc104 und Tc105  

Microsoft Academic Search

Molybdenum fission products from Uranium were rapidly separated using a sublimation technique. Their Technetium daughters could be separated from the Molybdenum sample by a second sublimation. The decay of Tc103, Tc104 and Tc105 was investigated using scintillation counters and coincidence methods. Tc103 decays by the emission of two beta-groups at energies of 2·0 Mev and 2·2 Mev followed by gamma-lines

P. Kienle; K. Wien; U. Zahn; B. Weckermann

1963-01-01

15

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

PubMed

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

16

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

17

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

18

Generations.  

PubMed

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

Chambers, David W

2005-01-01

19

Superatom representation of high-TC superconductivity  

NASA Astrophysics Data System (ADS)

A “super-atom” conceptual interface between chemistry and physics is proposed in order to assist in the search for higher TC superconductors. The plaquettes generating the checkerboard superstructure in the cuprates, the C60 molecules in K3C60, and the Mo6S82- clusters in Chevrel phase materials offer such candidate super-atoms. Thus, in the present study high-TC superconductivity HTSC is articulated as the entanglement of two disjoint electronic manifolds in the vicinity of a common Fermi energy. The resulting HTSC ground state couples near-degenerate protected local super-atom states to virtual magnons in an antiferromagnetic AFM embedding. The composite Cooper pairs emerge as the interaction particles for virtual magnons mediated “self-coherent entanglement” of super-atom states. A Hückel type resonating valence bond RVB formalism is employed in order to illustrate the real-space Cooper pairs as well as their delocalization and Bose Einstein condensation BEC on a ring of super-atoms. The chemical potential ?BEC for Cooper pairs joining the condensate is formulated in terms of the super-exchange interaction, and consequently the TC in terms of the Neél temperature. A rationale for the robustness of the HTSC ground state is proposed: achieving local maximum “electron correlation entropy” at the expense of non-local phase rigidity.

Panas, Itai

2012-10-01

20

La TC in medicina nucleare  

Microsoft Academic Search

\\u000a In questi ultimi anni gli strumenti di tomografia computerizzata (TC) sono apparsi sulla scena della medicina nucleare a integrare\\u000a tomografi PET (Positron Emission Tomography) e gamma-camere. Il primo prototipo di strumento ibrido, divenuto operativo nel 1998, comprendeva una componente PET e una\\u000a TC spirale montate sullo stesso supporto rotante [1]. I primi tomografi ibridi commerciali che seguirono, a partire dal

Duccio Volterrani; Oreste Sorace; Daniele Fontanelli

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

Power Systems Development Facility Gasification Test Campaign TC25  

SciTech Connect

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

Southern Company Services

2008-12-01

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

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

25

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

26

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

27

Cyclotron production of ??mTc: recycling of enriched ¹??Mo metal targets.  

PubMed

There is growing interest in the large scale cyclotron production of (99m)Tc via the (100)Mo(p,2n)(99m)Tc reaction. While the use and recycling of cyclotron-irradiated enriched molybdenum targets has been reported previously in the context of (94m)Tc production, to the best of our knowledge, previous recycling studies have been limited to the use of oxide targets. To facilitate reuse of high-power enriched (100)Mo targets, this work presents and evaluates a strategy for recycling of enriched metallic molybdenum. For the irradiated (100)Mo targets in this study, an overall metal to metal recovery of 87% is reported. Evaluation of "new" and "recycled" (100)Mo revealed no changes in the molybdenum isotopic composition (as measured via ICP-MS). For similar irradiation conditions of "new" and "recycled" (100)Mo, (i.e. target thicknesses, irradiation time, and energy), comparable levels of (94g)Tc, (95g)Tc, and (96g)Tc contaminants were observed. Comparable QC specifications (i.e. aluminum ion concentration, pH, and radiochemical purity) were also reported. We finally note that [(99m)Tc]-MDP images obtained by comparing MDP labelled with generator-based (99m)Tc vs. (99m)Tc obtained following the irradiation of recycled (100)Mo demonstrated comparable biodistribution. With the goal of producing large quantities of (99m)Tc, the proposed methodology demonstrates that efficient recycling of enriched metallic (100)Mo targets is feasible and effective. PMID:22750197

Gagnon, K; Wilson, J S; Holt, C M B; Abrams, D N; McEwan, A J B; Mitlin, D; McQuarrie, S A

2012-08-01

28

Giant electrocaloric effect around Tc.  

PubMed

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

Rose, Maimon C; Cohen, R E

2012-11-01

29

Tc-99 Ion Exchange Resin Testing  

SciTech Connect

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

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

2010-08-01

30

Power Systems Development Facility Gasification Test Campaing TC14  

SciTech Connect

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device (PCD), advanced syngas cleanup systems, and high pressure solids handling systems. This report details test campaign TC14 of the PSDF gasification process. TC14 began on February 16, 2004, and lasted until February 28, 2004, accumulating 214 hours of operation using Powder River Basin (PRB) subbituminous coal. The gasifier operating temperatures varied from 1760 to 1810 F at pressures from 188 to 212 psig during steady air blown operations and approximately 160 psig during oxygen blown operations.

Southern Company Services

2004-02-28

31

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

32

Grain boundaries in high-Tc superconductors  

Microsoft Academic Search

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

H. Hilgenkamp; J. Mannhart

2002-01-01

33

Oxidative dissolution potential of biogenic and abiogenic TcO 2 in subsurface sediments  

NASA Astrophysics Data System (ADS)

Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Tc is highly mobile in its most oxidized state [Tc(VII)O4-] and less mobile in the reduced form [Tc(IV)O 2· nH 2O]. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state; unconsolidated Pliocene-age fluvial sediment from the upper Ringold (RG) Formation at the Hanford Site and a clay-rich saprolite from the Field Research Center (FRC) background site on the Oak Ridge Site. Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Shewanella putrefaciens CN32 reduced Mn(III/IV) oxides and generated Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. After bioreduction and heat-killing, biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO 2-like phase in both sediments. The biogenic redox product Tc(IV) oxidized rapidly and completely in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular scale speciation of Tc compared to RG. X-ray microprobe, electron microprobe, X-ray absorption spectroscopy, and micro X-ray diffraction were applied to the whole sediment and isolated Tc-containing particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 ?m-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were attributed to mass-transfer-limited migration of O 2 into intra-aggregate and intraparticle domains where Tc(IV) existed; and the formation of unique, oxidation-resistant, intragrain Tc(IV)-Fe(III) molecular species.

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

2009-04-01

34

Scintillating 99Tc Selective Ion Exchange Resins  

SciTech Connect

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

Mitchell Greenhalgh; Richard D. Tillotson

2012-07-01

35

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

SciTech Connect

Both synthetically and naturally derived organic complexing agents in soil have been found in other studies to accelerate the rate of migration of specific radionuclides. In an effort to aid in the development of comprehensive plans for the disposal of low-level waste, the effect of organic complexing agents on the transport properties of /sup 99/Tc, a long-lived constituent of radioactive waste, was examined. The effect of ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and sodium citrate on the mobility of reduced Tc species was examined from two aspects: first, by techniques of desorption from soil in which reduced, sorbed Tc was exposed to solutions of organic ligands; and second, by exposure of synthetic Tc-organic complexes to soils. Only a slight desorption of reduced Tc from Hanford soil by EDTA was found to occur in 10-day desorption tests. However, when synthetic EDTA and DTPA complexes of reduced Tc were exposed to soil under similar conditions, only a slight amount of Tc was sorbed by the soil. This comparison clearly shows that at least one type of test did not reach equilibrium in the 10-day time period allowed. Although the effects of these complexants at equilibrium cannot be quantified from these data, it is obvious that they can have large effects on the mobility of reduced Tc. Desorption tests of reduced Tc from Hanford soil by citrate solutions showed definite indications of desorption only at a relatively high (0.01 M) citrate concentrations. Results with synthetic Tc(IV) and Tc(V) citrate complexes indicate the Tc(V) citrate complex to be strongly sorbed, while the Tc(IV) citrate complex was sorbed only slightly.

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

1982-02-01

36

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

37

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

38

Exp 99 Tc Vegetation Reference Material.  

National Technical Information Service (NTIS)

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

M. S. Feiner

1984-01-01

39

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

PubMed Central

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

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

2006-01-01

40

BBN TC2000 architecture and progamming models  

SciTech Connect

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

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

1990-11-01

41

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

PubMed

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

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

2014-02-01

42

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

43

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.

44

Spin fluctuations in Ni above TC  

NASA Astrophysics Data System (ADS)

Numerical computations of the temperature dependence of the cross section for the magnetic scattering of unpolarized neutrons in nickel above TC are reported. The calculations are based on semiempirical bands assuming no exchange splitting above TC . The thermal fluctuations are taken into account through the introduction of an effective temperature-dependent interaction, which is evaluated in the mode-mode coupling approximation. Cross sections are shown for constant-q scans for three different values of q and for several different temperatures from 650 to 946 K. There is some small structure in the calculated cross section due to band-structure effects, but we do not predict propagating spin waves above TC.

Rusek, P.; Callaway, J.

1988-04-01

45

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

46

Simple determination of (99)Tc in radioactive waste using Tc extraction disk and imaging plates.  

PubMed

A simple method was developed for determination of (99)Tc in low-level radioactive waste: Technetium-99 retained by a solid phase extraction disk was directly measured with imaging plates system. It was found that more than 97% of Tc were retained by the disk from a solution of pH 2 to 12, whereas depth profile of Tc in the disk, which greatly influences the counting efficiency, depended on solution pH. The present method was successfully applied to actual radioactive liquid waste samples arising from nuclear research facilities. PMID:19740672

Kameo, Y; Katayama, A; Hoshi, A; Haraga, T; Nakashima, M

2010-01-01

47

Synopsis of TC4 Missions and Meteorology  

Microsoft Academic Search

The TC4 (Tropical Composition, Clouds and Climate Coupling) Experiment conducted 26 aircraft sorties on 13 flight days from July 17 to August 8, 2007 (23 days). Quality science observations were also obtained during the transit flights to\\/from from San Jose, Costa Rica, where the mission was based. On 9 days, coordinated aircraft missions were flown with the NASA ER-2 and

D. Starr; L. Pfister; H. Selkirk; L. Nguyen

2007-01-01

48

An evolutionarily mobile antigen receptor variable region gene: Doubly rearranging NAR-TcR genes in sharks  

PubMed Central

Distinctive Ig and T cell receptor (TcR) chains define the two major lineages of vertebrate lymphocyte yet similarly recognize antigen with a single, membrane-distal variable (V) domain. Here we describe the first antigen receptor chain that employs two V domains, which are generated by separate VDJ gene rearrangement events. These molecules have specialized “supportive” TcR?V domains membrane-proximal to domains with most similarity to IgNAR V. The ancestral NAR V gene encoding this domain is hypothesized to have recombined with the TRD locus in a cartilaginous fish ancestor >200 million years ago and encodes the first V domain shown to be used in both Igs and TcRs. Furthermore, these data support the view that ?/? TcRs have for long used structural conformations recognizing free antigen. PMID:16549799

Criscitiello, Michael F.; Saltis, Mark; Flajnik, Martin F.

2006-01-01

49

Power Systems Development Facility Gasification Test Campaign TC16  

SciTech Connect

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

Southern Company Services

2004-08-24

50

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

51

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

Microsoft Academic Search

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

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

1994-01-01

52

Tc17, a Unique Subset of CD8 T Cells That Can Protect against Lethal Influenza Challenge1  

PubMed Central

We show here that IL-17-secreting CD4 T (Th)17 and CD8 T (Tc)17 effector cells are found in the lung following primary challenge with influenza A and that blocking Ab to IL-17 increases weight loss and reduces survival. Tc17 effectors can be generated in vitro using naive CD8 T cells from OT-I TCR-transgenic mice. T cell numbers expand 20-fold and a majority secretes IL-17, but little IFN-?. Many of the IL-17-secreting cells also secrete TNF and some secrete IL-2. Tc17 are negative for granzyme B, perforin message, and cytolytic activity, in contrast to Tc1 effectors. Tc17 populations express message for orphan nuclear receptor ?t and FoxP3, but are negative for T-bet and GATA-3 transcription factors. The FoxP3-positive, IL-17-secreting and IFN-?-secreting cells represent three separate populations. The IFN-?-, granzyme B-, FoxP3-positive cells and cells positive for IL-22 come mainly from memory cells and decrease in number when generated from CD44low rather than unselected CD8 T cells. Cells of this unique subset of CD8 effector T cells expand greatly after transfer to naive recipients following challenge and can protect them against lethal influenza infection. Tc17 protection is accompanied by greater neutrophil influx into the lung than in Tc1-injected mice, and the protection afforded by Tc17 effectors is less perforin but more IFN-? dependent, implying that different mechanisms are involved. PMID:19265125

Hamada, Hiromasa; de la Luz Garcia-Hernandez, Maria; Reome, Joyce B.; Misra, Sara K.; Strutt, Tara M.; McKinstry, Kai K.; Cooper, Andrea M.; Swain, Susan L.; Dutton, Richard W.

2009-01-01

53

Flavor changing top decay t-->c?~ or ?~-->tc¯ in the MSSM without R parity  

NASA Astrophysics Data System (ADS)

Widths for the new flavor-changing top quark decay t-->c?~ or for the reversed sneutrino decay ?~-->tc¯ are calculated in the minimal supersymmetric standard model without R-parity conservation. For large tan ?, e.g., tan ?~mt /mb~40, Br(t-->c?~)>10-5 or Br(?~-->tc¯)>10-6 in a relatively wide range of the supersymmetric parameter space as long as there is more than one nonzero R-parity violating coupling. In the best cases, with a typical squark mass around 100 GeV, we find that Br(t-->c?~)~10-4-10-3 or Br(?~-->tc¯)~10-5-10-4. For tan ?~O(1) the corresponding branching ratios for both top or sneutrino decays are too small to be measured at the CERN Large Hadron Collider (LHC). Therefore, the decays t-->c?~ or ?~-->tc¯ appear to be sensitive to tan ? and may be detected at the LHC. The branching ratios of the corresponding decays to an up quark instead of a charm quark, e.g., t-->u?~ or ?~-->t?, may also be similar.

Bar-Shalom, S.; Eilam, G.; Soni, A.

1999-08-01

54

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

55

The behavior of 99mTc-hexamethylpropyleneamineoxime (99mTc-HMPAO) in blood and brain.  

PubMed

99mTc-hexamethylpropyleneamineoxime (99mTc-HMPAO) is a reagent for scanning cerebral blood flow. We investigated how 99mTc-HMPAO changed in the blood and brain. The 99mTc-HMPAO, which was prepared by adding of 99mTcO4- to HMPAO and Sn(II), consisted of primary and secondary complexes, reduced hydrolyzed 99mTc, and 99mTc-pertechnetate. The percentage of the primary complex in 99mTc-HMPAO decreased with time after preparation. The primary complex converted to the secondary one very rapidly in the presence of plasma. When 99mTc-HMPAO was injected into patients, 99mTc activity was immediately partitioned in the plasma fraction, with approximately 60% in whole blood. In plasma, 99mTc was found to be associated with proteins such as albumin and globulin. 99mTc trapped in red cells was not washed out with either plasma or saline. Biodistribution studies showed that the less lipophilic compounds of 99mTc-HMPAO could not pass through the blood brain barrier (BBB), and therefore did not accumulate in the brain. The results of gel chromatography and equilibrium dialysis indicated that no specific 99mTc binding protein was present in the brain. Considering the instability of 99mTc-HMPAO in vivo, we proposed that the speed at which the primary complex converted to the less lipophilic compounds was important in allowing 99mTc-HMPAO to pass through the BBB and to be fixed in the brain. PMID:2920737

Nakamura, K; Tukatani, Y; Kubo, A; Hashimoto, S; Terayama, Y; Amano, T; Goto, F

1989-01-01

56

ISO/TC 172 'Optics And Optical Instruments'  

NASA Astrophysics Data System (ADS)

In the sixties and seventies, optical items were dealt with in several different Technical Committees of the International Standardization Organization (ISO). TC 10 'Technical drawings' got prepared to day down drawing rules for technical components, TC 22 'Road vehicles' defined terms of physiological optics because of the connection between seeing and driving motor vehicles, TC 59 'Building construction' standardized geodetic instruments, TC 94 'Personal safety - Protective clothing and equipment laid down requirements for sun glasses, and finally Working Group 12 of TC 42 'Photography' was going to work on various optical test methods and requirements for coatings.

Kittel, Hans F.

1989-04-01

57

High TC superconductors—composite wire fabrication  

Microsoft Academic Search

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

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

1987-01-01

58

Processing techniques for bulk high-Tc  

Microsoft Academic Search

Processing techniques for producing bulk high-Tc superconductors are reviewed and their merits are analyzed. Emphasis is placed on fabrication techniques for desirable geometries and processing techniques for improved properties. For commercial use ceramic superconductors are fabricated into various configurations (thin and thick films, bulk superconductors, metal-clad and metal-core composite wires, and metal-substrate composite ribbons). For many applications, the use of

Sungho Jin; Sungha

1991-01-01

59

High- Tc thin-film magnetometer  

SciTech Connect

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

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

1990-09-01

60

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

61

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

SciTech Connect

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

Harbour, J

2006-12-11

62

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

63

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

64

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

Microsoft Academic Search

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

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

1997-01-01

65

A Meteorological Overview of the TC4 Mission  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

66

High Tc superconducting materials and devices  

NASA Technical Reports Server (NTRS)

The high Tc Y1Ba2Cu3O(7-x) ceramic materials, initially developed in 1987, are now being extensively investigated for a variety of engineering applications. The superconductor applications which are presently identified as of most interest to NASA-LaRC are low-noise, low thermal conductivity grounding links; large-area linear Meissner-effect bearings; and sensitive, low-noise sensors and leads. Devices designed for these applications require the development of a number of processing and fabrication technologies. Included among the technologies most specific to the present needs are tapecasting, melt texturing, magnetic field grain alignment, superconductor/polymer composite fabrication, thin film MOD (metal-organic decomposition) processing, screen printing of thick films, and photolithography of thin films. The overall objective of the program was to establish a high Tc superconductivity laboratory capability at NASA-LaRC and demonstrate this capability by fabricating superconducting 123 material via bulk and thin film processes. Specific objectives include: order equipment and set up laboratory; prepare 1 kg batches of 123 material via oxide raw material; construct tapecaster and tapecaster 123 material; fabricate 123 grounding link; fabricate 123 composite for Meissner linear bearing; develop 123 thin film processes (nitrates, acetates); establish Tc and Jc measurement capability; and set up a commercial use of space program in superconductivity at LaRC. In general, most of the objectives of the program were met. Finally, efforts to implement a commercial use of space program in superconductivity at LaRC were completed and at least two industrial companies have indicated their interest in participating.

Haertling, Gene H.

1990-01-01

67

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

SciTech Connect

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

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

1981-12-01

68

Impurity-induced Tc reduction in high-temperature superconductors  

NASA Astrophysics Data System (ADS)

We study the effects of nonmagnetic impurities substituted for Cu atoms on the superconducting transition temperature Tc in high-temperature cuprate superconductors, using the d-p model within the fluctuation exchange approximation and the coherent potential approximation. Tc near the optimum-doped region reduces more rapidly than that for the over-doped region. We show that the rapid reduction of Tc is due mainly to the damping of the quasiparticle in our formalism.

Matsunaka, Daisuke; Kasai, Hideaki; Diño, Wilson Agerico; Nakanishi, Hiroshi

2004-11-01

69

Radioactive equilibrium: 99Mo/99mTc decay characteristics.  

PubMed

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

Chechev, Valery P; Bé, Marie-Martine

2014-05-01

70

TC-Oriented Supported Housing for Homeless MICAs  

Microsoft Academic Search

This article describes a TC-oriented aftercare program for homeless mentally ill chemical abusers (MICAs) in a supported housing facility, and presents some preliminary data on program effectiveness. The study divided the clients who had completed a residential modified TC program into two groups—those who participated in the TC-oriented supported housing program and those who did not. The data show similarities

Stanley Sacks; George De Leon; JoAnn Y. Sacks; Karen McKendrick; Barry S. Brown

2003-01-01

71

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

72

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

SciTech Connect

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

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

1996-08-01

73

Iron Oxide Waste Form for Stabilizing 99Tc  

SciTech Connect

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

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

2012-06-09

74

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

75

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

76

Graphoepitaxial high-Tc SQUIDs M. I. Faley1  

E-print Network

Graphoepitaxial high-Tc SQUIDs M. I. Faley1 , D. Meertens, U. Poppe and R. E. Dunin-Borkowski Peter of graphoepitaxially engineered high-Tc direct current superconducting quantum interferometer devices (DC SQUIDs to investigate the microstructural properties of DC SQUIDs with graphoepitaxial Josephson junctions. Both direct

Dunin-Borkowski, Rafal E.

77

Title: High-Tc DC SQUIDs for magnetoencephalography Presentation  

E-print Network

Title: High-Tc DC SQUIDs for magnetoencephalography Presentation Thursday, Oct 11, 2012, 9:00 AM Engineering & Electronics RAS, Moscow, Russian Federation. Keyword: ++16- SQUID designs and applications interference devices (SQUIDs), which rely on liquid helium. In contrast, high-Tc (HTc) DC SQUIDs are cooled

Dunin-Borkowski, Rafal E.

78

Tc17 Cells in Patients with Uterine Cervical Cancer  

PubMed Central

Background The existence of Tc17 cells was recently shown in several types of infectious and autoimmune diseases, but their distribution and functions in uterine cervical cancer (UCC) have not been fully elucidated. Methods The frequency of Tc17 cells in peripheral blood samples obtained from UCC patients, cervical intraepithelial neoplasia (CIN) patients and healthy controls was determined by flow cytometry. Besides, the prevalence of Tc17 cells and their relationships to Th17 cells and Foxp3-expressing T cells as well as microvessels in tissue samples of the patients were assessed by immunohistochemistry staining. Results Compared to controls, patients with UCC or CIN had a higher proportion of Tc17 cells in both peripheral blood and cervical tissues, but the level of Tc17 cells in UCC tissues was significantly higher than that in CIN tissues. Besides, the increased level of Tc17 in UCC patients was associated with the status of pelvic lymph node metastases and increased microvessel density. Finally, significant correlations of infiltration between Tc17 cells and Th17 cells or Foxp3-expressing T cells were observed in UCC and CIN tissues. Conclusions This study indicates that Tc17 cell infiltration in cervical cancers is associated with cancer progression accompanied by increased infiltrations of Th17 cells and regulatory T cells as well as promoted tumor vasculogenesis. PMID:24523865

Zhang, Yan; Hou, Fei; Liu, Xin; Ma, Daoxin; Zhang, Youzhong; Kong, Beihua; Cui, Baoxia

2014-01-01

79

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

80

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

SciTech Connect

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

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

1994-05-01

81

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

SciTech Connect

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

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

2008-05-15

82

Widespread occurrence of the Tc1 transposon family: Tc1-like transposons from teleost fish.  

PubMed

We characterized five transposable elements from fish: one from zebrafish (Brachydanio rerio), one from rainbow trout (Salmo gairdneri), and three from Atlantic salmon (Salmo salar). All are closely similar in structure to the Tc1 transposon of the nematode Caenorhabditis elegans. A comparison of 17 Tc1-like transposons from species representing three phyla (nematodes, arthropods, and chordates) showed that these elements make up a highly conserved transposon family. Most are close to 1.7 kb in length, have inverted terminal repeats, have conserved terminal nucleotides, and each contains a single gene encoding similar polypeptides. The phylogenetic relationships of the transposons were reconstructed from the amino acid sequences of the conceptual proteins and from DNA sequences. The elements are highly diverged and have evidently inhibited the genomes of these diverse species for a long time. To account for the data, it is not necessary to invoke recent horizontal transmission. PMID:7969029

Radice, A D; Bugaj, B; Fitch, D H; Emmons, S W

1994-09-28

83

The recovery of asteroid 2008 TC3  

NASA Astrophysics Data System (ADS)

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

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

2010-10-01

84

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

85

Photoreduction of 99Tc pertechnetate by nanometer-sized metal oxides: new strategies for formation and sequestration of low-valent technetium.  

PubMed

Technetium-99 ((99)Tc) (?(-)(max): 293.7 keV; t(1/2): 2.1 × 10(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 ((99)TcO(4)(-)) is stable. (99)TcO(4)(-) 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 (99)TcO(4)(-) and the chemical incorporation of the reduced (99)Tc into a metal oxide material. This strategy employs a single material, a polyoxometalate (POM), ?(2)-[P(2)W(17)O(61)](10-), that can be photoactivated in the presence of 2-propanol to transfer electrons to (99)TcO(4)(-) and incorporate the reduced (99)Tc covalently into the ?(2)-framework to form the (99)Tc(V)O species, (99)Tc(V)O(?(2)-P(2)W(17)O(61))(7-). This occurs via the formation of an intermediate species that slowly converts to (99)Tc(V)O(?(2)-P(2)W(17)O(61))(7-). Extended X-ray absorption fine structure and X-ray absorption near-edge spectroscopy analysis suggests that the intermediate consists of a (99)Tc(IV) ?(2)- species where the (99)Tc is likely bound to two of the four W-O oxygen atoms in the ?(2)-[P(2)W(17)O(61)](10-) defect. This intermediate then oxidizes and converts to the (99)Tc(V)O(?(2)-P(2)W(17)O(61))(7-) product. The reduction and incorporation of (99)TcO(4)(-) was accomplished in a "one pot" reaction using both sunlight and UV irradiation and monitored as a function of time using multinuclear nuclear magnetic resonance and radio thin-layer chromatography. The process was further probed by the "step-wise" generation of reduced ?(2)-P(2)W(17)O(61)(12-) through bulk electrolysis followed by the addition of (99)TcO(4)(-). The reduction and incorporation of ReO(4)(-), as a nonradioactive surrogate for (99)Tc, does not proceed through the intermediate species, and Re(V)O is incorporated quickly into the ?(2)-[P(2)W(17)O(61)](10-) defect. These observations are consistent with the periodic trends of (99)Tc and Re. Specifically, (99)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 the mechanisms of the reduction and incorporation of (99)Tc into a material. PMID:21985281

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

2011-11-23

86

Patients with hemoptysis examined by Tc99m sulfur colloid and Tc99m-labeled red blood cells: a preliminary appraisal  

Microsoft Academic Search

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

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

1984-01-01

87

An unconventional method for measuring the Tc L3-edge of technetium compounds.  

PubMed

Tc L3-edge XANES spectra have been collected on powder samples of SrTcO3 (octahedral Tc(4+)) and NH4TcO4 (tetrahedral Tc(7+)) immobilized in an epoxy resin. Features in the Tc L3-edge XANES spectra are compared with the pre-edge feature of the Tc K-edge as well as other 4d transition metal L3-edges. Evidence of crystal field splitting is obvious in the Tc L3-edge, which is sensitive to the coordination number and oxidation state of the Tc cation. The Tc L3 absorption edge energy difference between SrTcO3 (Tc(4+)) and NH4TcO4 (Tc(7+)) shows that the energy shift at the Tc L3-edge is an effective tool for studying changes in the oxidation states of technetium compounds. The Tc L3-edge spectra are compared with those obtained from Mo and Ru oxide standards with various oxidation states and coordination environments. Most importantly, fitting the Tc L3-edge to component peaks can provide direct evidence of crystal field splitting that cannot be obtained from the Tc K-edge. PMID:25343795

Blanchard, Peter E R; Reynolds, Emily; Kennedy, Brendan J; Ling, Chris D; Zhang, Zhaoming; Thorogood, Gordon; Cowie, Bruce C C; Thomsen, Lars

2014-11-01

88

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

89

A novel propulsion method for high- Tc superconducting maglev vehicle  

NASA Astrophysics Data System (ADS)

High-Tc superconducting (HTS) maglev is considered as a perfect transportation type because of its unique inherent stability. A direct current (DC) linear motor using the permanent magnet guideway (PMG) as the stator and the on-board coil as the rotor instead of the present inductive or synchronous alternate current (AC) linear motor which has an economic disadvantage due to the necessity to lay primary coil along the guideway is proposed in this paper. In order to modulate the magnetic field under the PMG, an inverse E shape ferromagnetic device (IESFD) core is designed. The possible winding method for the on-board coil is listed, and the analytical result shows that a considerable net ampere force and thus the propulsion force can be generated by this special structure. The influence of the concentrated effect of the IESFD on the maglev performance of HTS bulk is studied by a numerical program, and the results show that the levitation force with the IESFD is 90% of that without. It is also indicated that the load capability and lateral performance of the maglev vehicle combined this propulsion method can be improved thanks to the attractive effect between the IESFD and PMG. The cost of the HTS maglev vehicle will be remarkably reduced and then shorten the distance to practical application with this propulsion method.

Ma, Guangtong; Wang, Jiasu; Wang, Suyu; Liu, Minxian; Jing, Hua; Lu, Yiyun; Lin, Qunxu

2008-01-01

90

Power Systems Development Facility Gasification Test Campaign TC17  

SciTech Connect

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

Southern Company Services

2004-11-30

91

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

92

Interactions of Tc(IV) with humic substances  

SciTech Connect

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

Boggs, M. A. [Washington State University; Minton, Travis [Washington State University; Lomasney, Samuel [Washington State University; Islam, Mohammed [Washington State University; Dong, Wenming [ORNL; Gu, Baohua [ORNL; Wall, Nathalie [Washington State University

2011-01-01

93

New Generation, One-Part Cementitious-Pozzolanic (CP) Grouts  

E-print Network

New Generation, One-Part Cementitious-Pozzolanic (CP) Grouts for Ground Source Heat Loops Presented heat loops � Comparison of grouting materials � New generation cementitious-pozzolanic (CP) grouts � CP-Pozzolanic (CP) Grouts #12;New Generation CP Grouts DESIGN GOALS: � High TC (1.0­1.2). � One-bag mix ­ Batch

94

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

PubMed

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

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

2013-12-01

95

Synopsis of TC4 Missions and Meteorology  

NASA Astrophysics Data System (ADS)

The TC4 (Tropical Composition, Clouds and Climate Coupling) Experiment conducted 26 aircraft sorties on 13 flight days from July 17 to August 8, 2007 (23 days). Quality science observations were also obtained during the transit flights to/from from San Jose, Costa Rica, where the mission was based. On 9 days, coordinated aircraft missions were flown with the NASA ER-2 and DC-8, and with the NASA WB-57 on 3 occasions (and transit flights). The ER-2 served as an A-Train simulator (MODIS, CloudSat, CALIPSO, AIRS/TES, partial AMSR-E) while the WB-57 provided in-situ measurements of upper tropospheric cloud particles, aerosols and trace gases. The DC-8 provided both in-situ and remote sensing measurements, where the latter were focused on Aura validation, and also including a down-looking scanning precipitation radar (TRMM PR simulator). This paper will provide a synopsis of the science observations that were obtained, as regards the clouds and cloud systems sampled, from a meteorological perspective. A diversity of clouds were sampled and the meteorology proved more interesting than expected, at least to this author. Upper tropospheric cirrus outflows were sampled from a number of convective cloud systems including ITCZ-type systems as well as systems close to and affected by land. The low level inflows to these systems were also sampled in some cases (DC-8) and missions were flown to sample stratocumulus clouds over the Pacific Ocean exploiting the unique instrumentation on the DC-8 to add to the knowledge of these clouds which are so important to the Earth radiation budget. Measurements were made in the tropical Tropopause Transition Layer (TTL) by the WB-57. Upper tropospheric clouds and TTL properties and processes were central TC4 objectives. Excellent data were also obtained on the fate of the Saharan Air Layer and its aerosols over the Caribbean and Central America, as well as samples of plumes from volcanoes in Ecuador and Columbia and biogenic emissions over Columbia and the Pacific Ocean. Satellite observations, including those from various A-Train sensors, were used in planning the missions which were, in many cases, coordinated, at least in part, with satellite overpasses, especially Aura and other A-Train sensors (DC-8) and Terra.

Starr, D.; Pfister, L.; Selkirk, H.; Nguyen, L.

2007-12-01

96

The enhanced high Tc superconductivity by ordering dopant  

NASA Astrophysics Data System (ADS)

We discuss the high pressure improvement on superconducting transition temperature (Tc) related to ordering apical oxygen layer of a high temperature superconductor (HTS). This study became available in the high pressure synthesized Sr2CuO3+? superconductor with K2NiF4 structure showing so far rarely formed partially occupied ?apical oxygen? which also act as the dopant of the HTS. The well-defined links between Tc and modulated structures suggests that optimizing the ordering at apical oxygen layer outside CuO2 plane is a promising way to further enhance Tc.

Jin, Changqing; Liu, Q. Q.; Gao, W. B.; Yang, H.; Yang, L. X.; Yu, Y.; Yu, R. C.; Uchida, S.

2008-03-01

97

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

98

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

99

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

SciTech Connect

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

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

2006-04-05

100

Preservation of long-term memory and synaptic plasticity despite short-term impairments in the Tc1 mouse model of Down syndrome.  

PubMed

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 detailed analysis of cognitive function and synaptic plasticity in Tc1 mice. Here we show that Tc1 mice have impaired spatial working memory (WM) but spared long-term spatial reference memory (RM) in the Morris watermaze. Similarly, Tc1 mice are selectively impaired in short-term memory (STM) but have intact long-term memory (LTM) in the novel object recognition task. The pattern of impaired STM and normal LTM is paralleled by a corresponding phenotype in long-term potentiation (LTP). Freely-moving Tc1 mice exhibit reduced LTP 1 h after induction but normal maintenance over days in the dentate gyrus of the hippocampal formation. Biochemical analysis revealed a reduction in membrane surface expression of the AMPAR (alpha-amino-3-hydroxy-5-methyl-4-propionic acid receptor) subunit GluR1 in the hippocampus of Tc1 mice, suggesting a potential mechanism for the impairment in early LTP. Our observations also provide further evidence that STM and LTM for hippocampus-dependent tasks are subserved by parallel processing streams. PMID:18626093

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

2008-07-01

101

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

102

Quantum-size effects on Tc in superconducting nanofilms  

Microsoft Academic Search

An essential property of a high-quality metallic nanofilm is the quantization of the electron spectrum due to dimensional confinement in one direction. Quantum confinement has a substantial impact on the superconducting characteristics and leads to quantum-size variations of the critical temperature Tc with film thickness. We demonstrate that the Bogoliubov-de Gennes equations are able to describe the thickness-dependent Tc in

A. A. Shanenko; M. D. Croitoru; F. M. Peeters

2006-01-01

103

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

104

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

SciTech Connect

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

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

1981-09-01

105

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

PubMed

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

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

2008-03-01

106

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

PubMed

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

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

2004-01-01

107

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

108

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

109

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

PubMed Central

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

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

2014-01-01

110

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

111

Leukocyte labeling with isonitrile complexes of Tc-99m  

SciTech Connect

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

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

1985-05-01

112

Radionuclide imaging of myocardial infarction using Tc-99m TBI  

SciTech Connect

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

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

1985-05-01

113

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

114

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

115

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

116

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.

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

2014-01-01

117

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

118

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

SciTech Connect

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

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

2010-12-01

119

78 FR 7395 - Foreign-Trade Zone 129-Bellingham, WA; Notification of Proposed Production Activity; T.C. Trading...  

Federal Register 2010, 2011, 2012, 2013

...WA; Notification of Proposed Production Activity; T.C. Trading Company, Inc. (Eyeglass Assembly and...notification of proposed production activity on behalf of T.C. Trading Company, Inc. (T.C. Trading), located in Blaine,...

2013-02-01

120

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

121

RESEARCH ARTICLE 10.1002/2013TC003462  

E-print Network

by long-lived postseismic afterslip at Sefidabeh, east Iran, Tectonics, 33, doi:10.1002/2013TC003462 by long-lived postseismic afterslip at Sefidabeh, east Iran Alex Copley1 and Kirsty Reynolds1 1COMET sequence in east Iran, which shed light on the nature of the earthquake cycle and the mechanisms

122

Quantum Network Simulations of High Tc Ceramic Superconductors  

Microsoft Academic Search

Microwave absorption measurements of the high Tc ceramic superconductors reveal reproducible features in weak magnetic fields. These features are qualitatively explained by a quantum network model of these superconducting oxides. The ceramic superconductors are modeled as a set of one-dimensional wires weakly coupled at random nodes. The magnetoconductance, magnetization and susceptibility are computed from the network S-matrix.

Mark Jeffery; Charles Green; Somdev Tyagi; R. Gilmore

1988-01-01

123

Phase transformation in TC21 alloy during continuous heating  

Microsoft Academic Search

A dilatometry for investigating phase transformation in TC21 alloy was observed at constant heating rate. These experiments were conducted at a computer-controlled horizontal pushrod dilatometer to monitor the thermal expansion caused by the transformation as a function of heating time under different heating rates. Microstructures at different stages of the transformation had been observed by scanning electron microscopy. Results showed

YiHong Wang; Hongchao Kou; Hui Chang; ZhiShou Zhu; XiaoFan Su; Jinshan Li; Lian Zhou

2009-01-01

124

Development of High-Tc Superconducting Levitation compact flywheel  

Microsoft Academic Search

In this research, it proposes the development of High-Tc Superconducting Levitation compact flywheel. The permanent magnet magnetized in the thickness direction where the sectorial magnetic material plate is adsorbed creates the multipole field outside of the magnet. The levitation body achieved the stable rotation without the control by giving the driving force from the axial direction to the multipole field

I. Murakami; T. Sekiguti; S. Tomaru; Y. Ando; Y. Goto; K. Yamada

2009-01-01

125

Low temperature superfluid response of high-{Tc} superconductors  

SciTech Connect

The authors have reviewed the theoretical and experimental results of the low temperature superfluid response function {rho}{sub s}{sup {mu}} of high temperature superconductors (HTSC). In clean high-{Tc} materials the in-plane superfluid density {rho}{sub s}{sup ab} varies linearly with temperature. The slope of this linear T term is found to scale approximately with 1/{Tc} which, according to the weak coupling BCS theory for a d-wave superconductor, implies that the gap amplitude scales approximately with {Tc}. A T{sup 5} behavior of the out-of-plane superfluid density {rho}{sub s}{sup c} for clean tetragonal HTSC was predicted and observed experimentally in the single layer Hg-compound HgBa{sub 2}CuO{sub 4+{delta}}. In other tetragonal high-{Tc} compounds with relatively high anisotropy, such as Hg{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 8+{delta}}, {rho}{sub s}{sup c} varies linearly with temperature at low temperatures, but in underdoped YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}, {rho}{sub s}{sup c} varies at T{sup 2} at low temperatures; these results are consistent with the theoretical calculations.

Xiang, T. [Univ. of Cambridge (United Kingdom). Interdisciplinary Research Center in Superconductivity] [Univ. of Cambridge (United Kingdom). Interdisciplinary Research Center in Superconductivity; [Academia Sinica, Beijing (China). Inst. of Theoretical Physics; Panagopoulos, C.; Cooper, J.R. [Univ. of Cambridge (United Kingdom). Interdisciplinary Research Center in Superconductivity] [Univ. of Cambridge (United Kingdom). Interdisciplinary Research Center in Superconductivity

1998-04-20

126

Burning of high Tc bridges M. E. Gaevski,a)  

E-print Network

Burning of high Tc bridges M. E. Gaevski,a) T. H. Johansen, Yu. Galperin,a) and H. Bratsberg February 1997; accepted for publication 24 September 1997 Burning of superconducting thin film bridges that the destruction is preceded by significant penetration of magnetic field inside a weak-pinning region. In bridges

Johansen, Tom Henning

127

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

SciTech Connect

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

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

1980-01-01

128

Simultaneous ??m?Tc-MDP/¹²³I-MIBG imaging of neuroblastoma using SPECT-CT  

E-print Network

Simultaneous ??m??Tc-MDP/ ¹²³I-MIBG SPECT has the potential to replace current clinical sequential acquisitions of ??m?Tc-MDP and ¹²³-MIBG SPECT studies, and therefore has great potential to reduce imaging time, sedation ...

Pérez-Gutiérrez, José P. (José Pablo Andrés)

2011-01-01

129

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

130

Dipole Magnet from High Tc Superconductor  

NASA Astrophysics Data System (ADS)

The applicability of second-generation high-temperature superconductors (HTS) made from YBCO coated conductors in accelerator magnet technology was demonstrated by a consortium under the lead of Danfysik. A 3T demonstrator dipole magnet was designed, built and tested by the consortium. In total 2.5 km HTS tape was manufactured and tested by SuperPower. The tape was delivered in spool lengths 0varying from 93 m to 172 m and had a minimum Ic of 115 A or more. The tape was insulated with a 0.025 mm thin epoxy film before winding in total 14 saddle coils and 4 racetrack coils and subsequent impregnation with epoxy. All coils were azimuthally arranged in an ellipse configuration in order to achieve a cosine-theta-like current distribution around a circular good field with a diameter of 52 mm and a magnetic field length of 250 mm. The cold-mass consisting of the coil arrangement clamped in between a steel substrate and an aluminum collar and a surrounding laminated iron yoke, was mounted in a cryostat. The cold-mass is contact-cooled by two GM cryocoolers

Nielsen, Gunver; Zangenberg, Nikolaj; Hazelton, Drew; Hauge, Nils; Nielsen, Bjarne Roger; Møller, Søren Pape; Baurichter, Arnd

131

Synthesis, characterization and biodistribution of a new technetium-99m complex with trimethylsilylmethylisonitrile. Comparison with 99mTc-TBI and 99mTc-MIBI  

Microsoft Academic Search

An isonitrile ligand with a silicium component was synthesized and a copper salt of this ligand was then used to form a 99mTc complex. We evaluated the physicochemical characteristics of the complex and its biodistribution in rat. The chemical properties, i.e. lipophilic affinity and charge, were comparable to those of other 99mTc complexes formed with similar isonitrile compounds (99mTc-MIBI and

S. Bouquillon; Y. Coulais; M. Dartiguenave; J. A. M. Tafani; R. Guiraud

1995-01-01

132

Tumor targeting HPMA-porphyrin-(99m)Tc copolymer molecular imaging agent.  

PubMed

Porphyrins typically show preferential uptake and retention by tumor tissues via receptor-mediated endocytosis of low-density lipoproteins. To investigate the relative importance of active and passive targeting strategies, the synthesis, characterization, in vitro uptake, and in vivo biodistribution of specific targeting porphyrin HPMA [HPMA: N-(2-hydroxypropyl)methacrylamide] copolymer tracer poly(HPMA)-porphyrin-DTPA-(99m)Tc (DTPA: diethylenetriaminepentaacetic acid), nonspecific targeting HPMA copolymer tracer poly(HPMA)-DTPA-(99m)Tc, and nontargeting tracer DTPA-(99m)Tc are described in this study. The results showed that the cellular accumulation of poly(HPMA)-porphyrin-DTPA-(99m)Tc complex was found to be time-dependent. The uptake of poly(HPMA)-porphyrin-DTPA-(99m)Tc was significantly higher than that of poly(HPMA)-DTPA-(99m)Tc, indicating that uptake of the poly(HPMA)-porphyrin-DTPA-(99m)Tc was active binding. The uptake of poly(HPMA)-DTPA-(99m)Tc was significantly higher than that of DTPA-(99m)Tc, suggesting that uptake of the poly(HPMA)-DTPA-(99m)Tc was passive binding. Twenty-four hour necropsy data in the hepatocellular carcinoma tumor model showed significantly higher (p < 0.001) tumor localization for poly(HPMA)-porphyrin-DTPA-(99m)Tc (5.18 ± 0.50% ID/g [percentage injected dose per gram tissue]) compared with poly(HPMA)-DTPA-(99m)Tc (2.69 ± 0.15% ID/g) and DTPA-(99m)Tc (0.83 ± 0.03% ID/g). Moreover, higher T/B for poly(HPMA)-porphyrin-DTPA-(99m)Tc indicated reduced extravasation of the targeted polymeric conjugates in normal tissues. Thus, the poly(HPMA)-porphyrin-DTPA-(99m)Tc is a potential macromolecular tumor targeting molecular agent. PMID:25315509

Yuan, Long; Ma, Yabing; Yuan, Jianchao

2014-12-01

133

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

PubMed

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. Because of the small sample, statistically significant differences between both techniques were not ascertained. Both Tc-SC and Tc-RBC may prove to be helpful, minimally invasive imaging procedures for determining the general area of hemorrhage in patients with clinically significant hemoptysis. Although a trend suggests that Tc-RBC is a more sensitive method, further comparison is needed for corroboration. PMID:6484183

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

1984-11-01

134

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

135

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

136

Sleep spindles are generated in the absence of T-type calcium channel-mediated low-threshold burst firing of thalamocortical neurons  

PubMed Central

T-type Ca2+ channels in thalamocortical (TC) neurons have long been considered to play a critical role in the genesis of sleep spindles, one of several TC oscillations. A classical model for TC oscillations states that reciprocal interaction between synaptically connected GABAergic thalamic reticular nucleus (TRN) neurons and glutamatergic TC neurons generates oscillations through T-type channel-mediated low-threshold burst firings of neurons in the two nuclei. These oscillations are then transmitted from TC neurons to cortical neurons, contributing to the network of TC oscillations. Unexpectedly, however, we found that both WT and KO mice for CaV3.1, the gene for T-type Ca2+ channels in TC neurons, exhibit typical waxing-and-waning sleep spindle waves at a similar occurrence and with similar amplitudes and episode durations during non-rapid eye movement sleep. Single-unit recording in parallel with electroencephalography in vivo confirmed a complete lack of burst firing in the mutant TC neurons. Of particular interest, the tonic spike frequency in TC neurons was significantly increased during spindle periods compared with nonspindle periods in both genotypes. In contrast, no significant change in burst firing frequency between spindle and nonspindle periods was noted in the WT mice. Furthermore, spindle-like oscillations were readily generated within intrathalamic circuits composed solely of TRN and TC neurons in vitro in both the KO mutant and WT mice. Our findings call into question the essential role of low-threshold burst firings in TC neurons and suggest that tonic firing is important for the generation and propagation of spindle oscillations in the TC circuit. PMID:24282303

Lee, Jungryun; Song, Kiyeong; Lee, Kyoobin; Hong, Joohyeon; Lee, Hyojung; Chae, Sangmi; Cheong, Eunji; Shin, Hee-Sup

2013-01-01

137

TC-PTP is required for the maintenance of MYC-driven B-cell lymphomas  

PubMed Central

We sought to determine the contributions of protein tyrosine phosphatases (PTPs) to the pathogenesis of B-cell lymphomas. We found that T-cell PTP (TC-PTP) was overexpressed in transformed B cells. We hypothesized that TC-PTP may be a tumor-promoting gene that is regulated by MYC overexpression in B cells. Knockdown of TC-PTP in murine tumors resulted in decreased cell viability in vitro because of an arrest in the G1 phase of the cell cycle. Furthermore, cells with reduced TC-PTP expression were unable to either engraft or expand in vivo. Taken together, these data indicate that TC-PTP is required for B-cell tumor maintenance. Our data also suggested a correlation between TC-PTP expression and MYC overexpression. To investigate this further, we used malignant murine B cells that contain a doxycycline-repressible MYC transgene. We found that repression of MYC overexpression with doxycycline reduced TC-PTP expression. Moreover, enforced expression of TC-PTP showed partial rescue of the expansion of tumor cells after suppression of MYC overexpression. These results suggest that MYC overexpression induces TC-PTP overexpression, which in turn promotes tumor proliferation, implicating TC-PTP as an important effector of the MYC-driven proliferation program in B-cell lymphomas. Thus, TC-PTP may be a suitable molecular target for the treatment of B-cell lymphomas. PMID:19755676

Young, Ryan M.; Polsky, Avital

2009-01-01

138

Transposable elements belonging to the Tc1-Mariner superfamily are heavily mutated in Colletotrichum graminicola.  

PubMed

Transposable elements are ubiquitous and constitute an important source of genetic variation in addition to generating deleterious mutations. Several filamentous fungi are able to defend against transposable elements using RIP(repeat-induced point mutation)-like mechanisms, which induce mutations in duplicated sequences. The sequenced Colletotrichum graminicola genome and the availability of transposable element databases provide an efficient approach for identifying and characterizing transposable elements in this fungus, which was the subject of this study. We identified 132 full-sized Tc1-Mariner transposable elements in the sequenced C. graminicola genome, which were divided into six families. Several putative transposases that have been found in these elements have conserved DDE motifs, but all are interrupted by stop codons. An in silico analysis showed evidence for RIP-generated mutations. The TCg1 element, which was cloned from the Brazilian 2908 m isolate, has a putative transposase sequence with three characteristic conserved motifs. However, this sequence is interrupted by five stop codons. Genomic DNA from various isolates was analyzed by hybridization with an internal region of TCg1. All of the isolates featured transposable elements that were similar to TCg1, and several hybridization profiles were identified. C. graminicola has many Tc1-Mariner transposable elements that have been degenerated by characteristic RIP mutations. It is unlikely that any of the characterized elements are autonomous in the sequenced isolate. The possible existence of active copies in field isolates from Brazil was shown. The TCg1 element is present in several C. graminicola isolates and is a potentially useful molecular marker for population studies of this phytopathogen. PMID:24895425

Braga, Raíssa Mesquita; Santana, Mateus Ferreira; Veras da Costa, Rodrigo; Brommonschenkel, Sergio Herminio; de Araújo, Elza Fernandes; de Queiroz, Marisa Vieira

2014-01-01

139

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

140

Technical issues of a high-Tc superconducting bulk magnet  

NASA Astrophysics Data System (ADS)

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

Fujimoto, Hiroyuki

2000-06-01

141

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

142

Averaged effective pinning potential in YBCO single crystals near Tc  

NASA Astrophysics Data System (ADS)

The dynamics of magnetic flux trapped in low dc magnetic fields (of the order of the Earth's field) was for the first time studied experimentally in single-crystal YBCO samples with unidirectional twin boundaries in the temperature range near Tc (0.8 < T/Tc < 0.99). Strong pinning in the system of unidirectional planar defects was demonstrated, and a significant deviation from monotonous behavior was established for the averaged effective pinning potential Up(T) for the trapped flux of low density. In order to compare different methods of Jc determination, the field dependences of the magnetization loop width M(H), which are related to the effective pinning and Jc, were obtained, and resistive measurements on microbridges made from the same single crystals were carried out.

Monarkha, V. Yu.; Sivakov, A. G.; Timofeev, V. P.

2014-09-01

143

Spinless Impurities in High- Tc Cuprates: Kondo-Like Behavior  

NASA Astrophysics Data System (ADS)

We compare the effects of in-plane nonmagnetic Li+ and Zn2+ impurities on the normal state of high- Tc cuprates. 89Y NMR shows that the extra hole introduced by Li is not localized in its vicinity. The Tc depression and induced moments on near neighbor Cu sites of Zn or Li are found to be identical. These effects of spinless impurities establish the major influence of the spin perturbation with respect to the charge defect. The susceptibility of the induced moment measured by 7Li NMR displays a 1/\\(T+?\\) behavior. ? increases with doping up to about 200 K in the overdoped regime. We attribute this to a ``Kondo-like'' effect.

Bobroff, J.; Macfarlane, W. A.; Alloul, H.; Mendels, P.; Blanchard, N.; Collin, G.; Marucco, J.-F.

1999-11-01

144

Thermal desorption of 3He from T@C 60  

NASA Astrophysics Data System (ADS)

The interaction of recoil tritium (T), with an initial kinetic energy of 2.7 MeV with C 60 molecules, is studied in a 6Li( n, ?) T activated homogenized compound matrix of Li 2CO 3 and C 60. Liquid scintillation spectrometry coupled with high pressure liquid chromatography (HPLC) revealed endohedral T insertion into the fullerene cage upon extraction of the fullerene species into the organic phase. Solid state temperature programmed desorption profiles of the activated compound target showed the desorption of 3He gas (as a ?- decay product from T) from the endohedral T@C 60 at 882 °C. The deconvoluted evolved gas analysis-mass spectral (EGA-MS) data provided a 25% probability of T@C 60 formation upon nuclear activation of the compound target. The non-isothermal kinetics of the tritium desorption, studied as a function of temperature, revealed the process to be diffusion controlled.

Sahoo, Rashmi R.; Patnaik, Archita

2001-11-01

145

Decomposition of Tc-99m pyrophosphate by peroxides in pertechnetate used in preparation  

SciTech Connect

We describe an investigation of the stability of Tc-99m pyrophosphate (Tc-99m PPi). We have shown that addition of exogenous hydrogen peroxide to Tc-99m PPi can initiate the oxidation of the complex, giving rise to 95% unbound pertechnetate. The presence of endogenous hydrogen peroxide in the sodium pertechnetate used in the preparation of Tc-99m PPi has been thought to influence its stability. We have prepared it using pertechnetate solutions of different specific activities. After preparation, an alumina column was used to detect free /sup 99m/TcO/sub 4//sup -/. The Tc-99m PPi and Na/sup 99m/TcO/sub 4/ solutions were then assayed by iodometric titration for hydrogen peroxide, which was detected in the pertechnetate solutions. The higher the specific activity of the solution used for the tracer preparation, the faster was the production of free pertechnetate.

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

1981-07-01

146

Decomposition of Tc-99m pyrophosphate by peroxides in pertechnetate used in preparation  

SciTech Connect

We describe an investigation of the stability of Tc-99m pyrophosphate (Tc-99m PPi). We hve shown that addition of exogenous hydrogen peroxide to Tc-99m PPi can initiate the oxidation of the complex, giving rise to 95% unbound pertechnetate. The presence of endogenous hydrogen peroxide in the sodium pertechnetate used in the preparation of Tc-99m PPi has been thought to influence its stability. We have prepared it using pertechnetate solutions of different specific activities. After preparation, an alumina column was used to detect free /sup 99m/Tc/sub 4/-. The Tc-99m PPi and Na/sup 99m/TcO/sub 4/ solutions were then assayed by iodometric titration for hydrogen peroxide, which was detected in the pertechnetate solutions. The higher the specific activity of the solution used for the tracer preparation, the faster was the production of free pertechnetate.

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

1981-07-01

147

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

148

Tc-99m pyrophosphate myocardial scanning in Chagas' disease  

SciTech Connect

Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas's disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

Goncalves da Rocha, A.F. (Hospital Beneficencia Portuguesa, Rio de Janeiro, Brazil); Meguerian, B.A.; Harbert, J.C.

1981-04-01

149

Tc-99m pyrophosphate myocardial scanning in Chagas' disease  

SciTech Connect

Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas' disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

da Rocha, A.F.; Meguerian, B.A.; Harbert, J.C.

1981-04-01

150

Numerical analysis of magnetization of a bulk high {Tc} superconductor  

SciTech Connect

Magnetization of a bulk high {Tc} superconductor (HTSC) is evaluated with the numerical simulation codes. The field-cooled magnetization of the HTSC is analyzed by using the critical state model. The pulse magnetization process is also analyzed by using the flux creep-flow model. The numerical solutions are discussed to clarify the time depending effects in the reported experimental results on the pulse magnetization.

Tsuchimoto, M.; Waki, H.; Honma, T. [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering] [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Itoh, Y.; Yanagi, Y.; Yoshikawa, M.; Oka, T. [IMRA Material R and D Co., Ltd., Kariya, Aichi (Japan)] [IMRA Material R and D Co., Ltd., Kariya, Aichi (Japan); Yamada, Y.; Mizutani, U. [Nagoya Univ. (Japan). Dept. of Crystalline Materials Science] [Nagoya Univ. (Japan). Dept. of Crystalline Materials Science

1996-05-01

151

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

152

Enhanced Tc in MgB2 by SWCNT Dilution  

NASA Astrophysics Data System (ADS)

We report for the first time a nonsubstitutional hole-doping of the MgB2 structure and an increase in Tc by SWCNT dilution. The SWCNT concentration was varied from 0.05wt% to 5wt%. We investigated the temperature dependence resistivity from 10K to 300K of sintered MgB2 powder containing dilute amount of ultra-high purity single wall carbon nanotubes. Micro-Raman spectroscopy, field emission scanning electron microscope and x-ray diffraction were used to analyze the interfacial interactions between the carbon nanotubes and the magnesium diboride grains. We obtained an increase in Tc from 41.1K to 45.8K. This is attributed charge transfer: electron transfer from the MgB2 structure to the SWCNT structure. This consequently leads to hole-doping of the MgB2 structure and the enhancement we see in Tc. This is confirmed by micro-Raman analysis of the phonon states of the SWCNT in the composites. This is explained in terms of the interplay between impurity scattering and hole-doping. This report provides experimental alternative pathway to hole-doping of MgB2 without appealing to elemental substitution.

Ma, Danhao; Jayasinha, Ruwantha; Adu, Kofi; Sumanasekera, Gamini

2013-03-01

153

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

154

Nernst signal generated by superconducting fluctuations in low-Tc disordered superconductors  

NASA Astrophysics Data System (ADS)

In amorphous superconducting thin films of Nb0.15Si0.85 [1][2] and InOx [3][4], a finite Nernst coefficient can be detected in a wide range of temperature and magnetic field. Due to the negligible contribution of normal quasi-particles, superconducting fluctuations easily dominate the Nernst response in the entire range of study. In the vicinity of the critical temperature and in the zero-field limit, the magnitude of the signal is in quantitative agreement with what is theoretically expected for the Gaussian fluctuations of the superconducting order parameter. Even at higher temperatures and finite magnetic field, the Nernst coefficient is set by the size of superconducting fluctuations. The Nernst coefficient emerges as a direct probe of the ghost critical field, the normal-state mirror of the upper critical field. Moreover, upon leaving the normal state with fluctuating Cooper pairs, we show that the temperature evolution of the Nernst coefficient is different whether the system enters a vortex solid, a vortex liquid or a phase-fluctuating superconducting regime. [1] A. Pourret et al., Nature Physics 2, 683 - 686 (2006) [2] A. Pourret et al., Phys. Rev. B. 76, 214504 (2007) [3] P. Spathis et al., Europhys. Lett. 83, 57005 (2008) [4] A. Pourret et al., New Journal of Physics 11, 055071 (2009)

Pourret, A.; Spathis, P.; Aubin, H.; Behnia, K.

2010-03-01

155

Electrical generation  

NSDL National Science Digital Library

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

Project, Iowa P.

2004-01-01

156

(99m)Tc-Galacto-RGD2: a novel 99mTc-labeled cyclic RGD peptide dimer useful for tumor imaging.  

PubMed

This study sought to evaluate [(99m)Tc(HYNIC-Galacto-RGD2)(tricine)(TPPTS)] ((99m)Tc-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, Pawe?; Chauhan, Satendra; Pennington, Michael; Liu, Shuang

2013-09-01

157

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; Sowinski, Pawel; Chauhan, Satendra; Pennington, Michael; Liu, Shuang

2013-01-01

158

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

SciTech Connect

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

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

1981-09-01

159

99mTc-labelling of leucocytes with 99mTc-DPO: a complex developed for myocardial imaging.  

PubMed

The lipophilic 99mTc-DPO complex, developed as a myocardial imaging radiopharmaceutical, was used to label leucocytes. After an incubation of 0.1 ml 99mTc-DPO (8 micrograms DMPE*2HCl) with mixed leucocytes in plasma, the labelling efficiency was over 70%. During incubation in 5 ml plasma, a loss of activity was found between 20% (1 h) and 35% (3 h) caused by elution. Disturbances of cell viability could not be found with the help of the chemiluminescence test. The in vivo recovery was determined in three dogs and was 45%-50% (0.5 h), 30%-36% (1 h), and 18%-24% (3 h). Autologous 99mTc-DPO-leucocytes were used on seven patients with suspected osteomyelitis, there were four true negative and three true positive results. The target/nontarget ratio determined by ROI in the positive cases was 1.8 to 2.5 at 3 h after injection. PMID:2547618

Endert, G; Franke, U; Kleinert, P

1989-01-01

160

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

161

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

SciTech Connect

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

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

2006-08-15

162

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

163

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

PubMed

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

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

2014-01-01

164

Justification of administered dose level in brain perfusion imaging with 99mTc-HMPAO  

NASA Astrophysics Data System (ADS)

Brain perfusion imaging by means of 99mTc-HMPAO is widely used in the diagnosis of Alzheimer's disease. The administered dose range recommended by the manufacturer and reported in bibliography is rather wide (~ 9.5 - 27 mCi), necessitating further quantitative analysis. In the framework of this study, a quantitative evaluation of the radiopharmaceutical performance for different values of administered dose was carried out, based on image quality indicators. Evaluation of image quality was based on wavelet-generated contrast, noise, and contrast-to-noise ratio indicators, denoted as CI, NI and CNR respectively. Subsequently, a generic image quality index was correlated with the administered dose, to produce an overall performance indicator (denoted as PI). Application of appropriate statistical tests (analysis of variance for normal and Kruskal-Wallis test for non-normal distributions) showed that there is a statistically significant difference in CI (p < 0.01), NI (p < 0.001) and CNR (p < 0.05), but not in PI (p > 0.05) values. Application of Tukey test for CI and NI normal distributions demonstrated that CI (10 mCi) = CI (20 mCi) < CI (15 mCi) and NI (10 mCi) > NI (20 mCi), while NI (15 mCi) could not be characterised. Finally, application of non-parametric multiple comparisons showed that CNR (20 mCi) < CNR (10 mCi), while CNR (15 mCi) could not be characterised. Consequently, brain perfusion imaging, by means of 99mTc-HMPAO utilising an administered dose of 20 mCi, results in improved image quality on the basis of the estimated indicators. Additionally, this image quality improvement is sufficient to justify the increased patient radiation burden.

Stefanoyiannis, A. P.; Gerogiannis, I.; Geronikola-Trapali, X.; Armeniakos, I.; Prentakis, A.; Soultanis, S.; Chatziioannou, S. N.

2011-09-01

165

Strong thermal fluctuations in cuprate superconductors in magnetic fields above Tc  

NASA Astrophysics Data System (ADS)

Recent measurements of fluctuation diamagnetism in high-temperature superconductors show distinct features above and below Tc, which can not be explained by simple Gaussian fluctuation theory. Self-consistent calculation of magnetization in layered high-temperature superconductors, based on the Ginzburg-Landau-Lawrence-Doniach model and including all Landau levels is presented. The results agree well with the experimental data in a wide region around Tc, including both the vortex liquid below Tc and the normal state above Tc. The Gaussian fluctuation theory significantly overestimates the diamagnetism for strong fluctuations. It is demonstrated that the intersection point of magnetization curves appears in the region where the lowest Landau level contribution dominates and magnetization just below Tc is nonmonotonic. Our calculation supports the phase disordering picture of fluctuations above Tc.

Jiang, Xujiang; Li, Dingping; Rosenstein, Baruch

2014-02-01

166

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

SciTech Connect

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

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

1984-07-01

167

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

SciTech Connect

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

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

1984-07-01

168

Magnetic correlation in itinerant magnetic materials above TC (invited)  

NASA Astrophysics Data System (ADS)

Although the properties of magnetic insulators are relatively well understood, the same cannot be said of materials in which the unpaired electrons participate in the Fermi surface. A number of conflicting theories exist which all give a more or less satisfactory account of the ground state properties of magnetic metals but give widely different descriptions of magnetic fluctuations above the ordering temperature (TC). The paramagnetic state of a material can be characterized by the spin-density spin-density correlation function (SDSDCF) which is accessible to measurement through the magnetic scattering cross section. We have made measurements of the paramagnetic scattering from the transition metals Cr, Mn, Fe, Ni, and a number of intermetallic compounds over a wide range of temperature. Polarization analysis was used to separate the magnetic part of the scattering cleanly. In all cases where atoms with open d shells are in contact we have found significant structure in the SDSDCF over a range of several interatomic distances. This has loosely been called ``short range order above TC.'' The resolution of the spectrometer for the majority of the measurements was some 12 THz FWHM, so that although the true equal time SDSDCF is not obtained, essentially all contributions with a lifetime greater than 5×10-10 s are included and in particular most of the thermal fluctuations up to kTC. The paramagnetic scattering results are coherent with inelastic neutron scattering data both above and below the transition temperature. It has been found difficult to give a consistent account of all these results using theories based on extensions of the Heisenberg model. The fluctuating band models, in which correlations in the paramagnetic phase appear naturally, seem more appropriate.

Brown, P. J.; Ziebeck, K. R. A.; Déportes, J.; Givord, D.

1984-03-01

169

Homopolar Generator.  

National Technical Information Service (NTIS)

The homopolar generators are used in very high direct current applications. A more efficient type of homopolar generator rotor is provided having at load conditions a lower internal voltage drop and lower excitation power requirements than prior art devic...

E. E. Musset

1965-01-01

170

Chart Generation  

Microsoft Academic Search

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

Martin Kay

1996-01-01

171

Transcribed Tc1-like transposons in salmonid fish  

PubMed Central

Background Mobile genetic elements comprise a substantial fraction of vertebrate genomes. These genes are considered to be deleterious, and in vertebrates they are usually inactive. High throughput sequencing of salmonid fish cDNA libraries has revealed a large number of transposons, which remain transcribed despite inactivation of translation. This article reports on the structure and potential role of these genes. Results A search of EST showed the ratio of transcribed transposons in salmonid fish (i.e., 0.5% of all unique cDNA sequences) to be 2.4–32 times greater than in other vertebrate species, and 68% of these genes belonged to the Tc1-family of DNA transposons. A phylogenetic analysis of reading frames indicate repeated transposition of distantly related genes into the fish genome over protracted intervals of evolutionary time. Several copies of two new DNA transposons were cloned. These copies showed relatively little divergence (11.4% and 1.9%). The latter gene was transcribed at a high level in rainbow trout tissues, and was present in genomes of many phylogenetically remote fish species. A comparison of synonymous and non-synonymous divergence revealed remnants of divergent evolution in the younger gene, while the older gene evolved in a neutral mode. From a 1.2 MB fragment of genomic DNA, the salmonid genome contains approximately 105 Tc1-like sequences, the major fraction of which is not transcribed. Our microarray studies showed that transcription of rainbow trout transposons is activated by external stimuli, such as toxicity, stress and bacterial antigens. The expression profiles of Tc1-like transposons gave a strong correlation (r2 = 0.63–0.88) with a group of genes implicated in defense response, signal transduction and regulation of transcription. Conclusion Salmonid genomes contain a large quantity of transcribed mobile genetic elements. Divergent or neutral evolution within genomes and lateral transmission can account for the diversity and sustained persistence of Tc1-like transposons in lower vertebrates. A small part of transposons remain transcribed and their transcription is enhanced by responses to acute conditions. PMID:16095544

Krasnov, Aleksei; Koskinen, Heikki; Afanasyev, Sergey; Molsa, Hannu

2005-01-01

172

Intrinsic Josephson effects in high-Tc superconductors  

Microsoft Academic Search

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

R. Kleiner; P. Müller

1994-01-01

173

Microstructures and critical currents in high-{Tc} superconductors  

SciTech Connect

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

Suenaga, Masaki

1998-11-01

174

Tc-99m DTPA uptake in extramedullary plasmacytoma of the retroperitoneum  

SciTech Connect

A case is presented in which uptake of Tc-99m DTPA has been demonstrated in an extramedullary plasmacytoma of the retroperitoneum. Because Ga-67 citrate does not concentrate in the same areas as Tc-99m DTPA, a radionuclide-specific uptake mechanism may be present. Extramedullary plasmacytoma should be included in the list of possible causes if extrarenal or extracentral nervous system uptake of Tc-99m DTPA occurs.

Aburano, T.; Yokoyama, K.; Michigishi, T.; Tonami, N.; Hisada, K.

1988-12-01

175

Development of (99m)Tc-N4-NIM for molecular imaging of tumor hypoxia.  

PubMed

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 (99m)Tc. The present study was aimed to develop (99m)Tc-cyclam-2-nitroimidazole ((99m)Tc-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 (99m)Tc-N4-NIM and (99m)Tc-N4 was obtained in 13762 rat mammary tumor cells and mesothelioma cells in 6-well plates. Tissue distribution of (99m)Tc-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 (99m)Tc-N4-NIM was >96% by HPLC. Cell uptake of (99m)Tc-N4-NIM was higher than (99m)Tc-N4 in both cell lines. Biodistribution of (99m)Tc-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 (99m)Tc-N4-NIM in animal models. Efficient synthesis of N4-NIM was achieved. (99m)Tc-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

176

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

SciTech Connect

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

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

1994-10-01

177

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

SciTech Connect

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

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

1988-08-01

178

Lipid raft microdomain compartmentalization of TC10 is required for insulin signaling and GLUT4 translocation.  

PubMed

Recent studies indicate that insulin stimulation of glucose transporter (GLUT)4 translocation requires at least two distinct insulin receptor-mediated signals: one leading to the activation of phosphatidylinositol 3 (PI-3) kinase and the other to the activation of the small GTP binding protein TC10. We now demonstrate that TC10 is processed through the secretory membrane trafficking system and localizes to caveolin-enriched lipid raft microdomains. Although insulin activated the wild-type TC10 protein and a TC10/H-Ras chimera that were targeted to lipid raft microdomains, it was unable to activate a TC10/K-Ras chimera that was directed to the nonlipid raft domains. Similarly, only the lipid raft-localized TC10/ H-Ras chimera inhibited GLUT4 translocation, whereas the TC10/K-Ras chimera showed no significant inhibitory activity. Furthermore, disruption of lipid raft microdomains by expression of a dominant-interfering caveolin 3 mutant (Cav3/DGV) inhibited the insulin stimulation of GLUT4 translocation and TC10 lipid raft localization and activation without affecting PI-3 kinase signaling. These data demonstrate that the insulin stimulation of GLUT4 translocation in adipocytes requires the spatial separation and distinct compartmentalization of the PI-3 kinase and TC10 signaling pathways. PMID:11502760

Watson, R T; Shigematsu, S; Chiang, S H; Mora, S; Kanzaki, M; Macara, I G; Saltiel, A R; Pessin, J E

2001-08-20

179

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

180

Plasma clearance and biodistribution of oxidatively modified 99mTc-beta-VLDL in rabbits.  

PubMed

The biodistribution and removal from plasma (measured as fractional clearance rate, FCR, per hour) of native and oxidatively modified 99mtechnetium-labeled beta-very low density lipoprotein (99mTc-beta-VLDL) were investigated in hypercholesterolemic (HC) and control (C) three-month old New Zealand rabbits. The intracellular accumulation of beta-VLDL labeled with 99mTc was studied in vitro in THP-1 cells and monocyte-derived macrophages isolated from rabbits. After intravenous injection into C rabbits, copper-oxidized beta-VLDL (99mTc-ox-beta-VLDL) was cleared from the circulation faster (0.362 +/- 0.070/h) than native beta-VLDL (99mTc-nat-beta-VLDL, 0.241 +/- 0.070/h). In contrast, the FCR of 99mTc-ox-beta-VLDL in HC rabbits was lower (0.100 +/- 0.048/h) than that of 99mTc-nat-beta-VLDL (0.163 +/- 0.043/h). The hepatic uptake of radiolabeled lipoproteins was lower in HC rabbits (0.114 +/- 0.071% injected dose/g tissue for 99mTc-nat-beta-VLDL and 0.116 +/- 0.057% injected dose/g tissue for 99mTc-ox-beta-VLDL) than in C rabbits (0.301 +/- 0.113% injected dose/g tissue for 99mTc-nat-beta-VLDL and 0.305 +/- 0.149% injected dose/g tissue for 99mTc-ox-beta-VLDL). The uptake of 99mTc-nat-beta-VLDL and 99mTc-ox-beta-VLDL by atherosclerotic aorta lesions isolated from HC rabbits (99mTc-nat-beta-VLDL: 0.033 +/- 0.012% injected dose/g tissue and 99mTc-ox-beta-VLDL: 0.039 +/- 0.017% injected dose/g tissue) was higher in comparison to that of non-atherosclerotic aortas from C rabbits (99mTc-nat-beta-VLDL: 0.023 +/- 0.010% injected dose/g tissue and 99mTc-ox-beta-VLDL: 0.019 +/- 0.010% injected dose/g tissue). However, 99mTc-nat-beta-VLDL and 99mTc-ox-beta-VLDL were taken up by atherosclerotic lesions at similar rates. In vitro studies showed that both monocyte-derived macrophages isolated from rabbits and THP-1 macrophages significantly internalized more 99mTc-ox-beta-VLDL than 99mTc-nat-beta-VLDL. These results indicate that in cholesterol-fed rabbits 99mTc-ox-beta-VLDL is slowly cleared from plasma and accumulates in atherosclerotic lesions. However, although the extent of in vitro uptake of 99mTc-ox-beta-VLDL by macrophages was high, the in vivo accumulation of this radiolabeled lipoprotein by atherosclerotic lesions did not differ from that of 99mTc-nat-beta-VLDL. PMID:9292106

Silva, E L; Meneghetti, J C; Coelho, I J; Abdalla, D S

1997-06-01

181

Differential uptake of Tc-99m DMSA and Tc-99m EC in renal tubular disorders: Report of two cases and review of the literature.  

PubMed

Tc-99m DMSA and Tc-99m EC studies are invaluable functional imaging modalities for renal structural and functional assessment. Normally, the relative renal function estimated by the two methods correlates well with each other. We here present two patients with renal tubular acidosis who showed impaired/altered DMSA uptake with normal EC renal dynamic study depicting the pitfall of DMSA imaging in tubular disorders. The two presented cases also depict distinct pattern of Tc-99m DMSA scintigraphic findings in patients with proximal and distal renal tubular acidosis, thus highlighting the factors affecting DMSA kinetics. PMID:25210282

Reddy Gorla, Arun Kumar; Agrawal, Kanhaiyalal; Sood, Ashwani; Bhattacharya, Anish; Mittal, Bhagwant Rai

2014-07-01

182

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

183

99mTc-sodium pertechnetate permeation into cerebrospinal fluid.  

PubMed

The integrity of the blood-brain barrier may be reflected by the blood and cerebrospinal fluid (CSF) if these two compartments are sampled at an appropriate interval after the administration of certain substances. After reading through the controversial literature, this study was undertaken to determine the frequency with which 99mTc-sodium pertechnetate entered the CSF to an abnormal extent, and to see whether this was related to any particular pathology. The plasma-to-CSF ratios were determined in 51 patients 4 hours following the intravenous administration of 0.5-10 mCi 99mTc-sodium pertechnetate. In 23 patients with active CNS tuberculosis, the mean value of the pertechnetate plasma-to-CSF ration was 32.12. In contradistinction, the plasma-to-CSF pertechnetate in 28 nontuberculous subjects was considerably higher (144.63). For the purpose of correlation, a 82Br partition test was also done on each subject 48 hours following the oral administration of NH82Br. The 48-hour study in each of these cases was generally in agreement with the pertechnetate studies: the plasma-to-CSF ratio mean value was 1.25 in patients with active CNS tuberculosis, while for the nontuberculous patients it was 3.32. PMID:466905

Borkar, A; DaCosta, H

1979-07-01

184

Structural investigations of recently discovered high Tc superconductors.  

PubMed

A short overview is given of the possibilities of electron microscopy in the determination of the local, atomic scale structure of high Tc superconducting materials. Examples include the detection of weak oxygen ordering, description and characterization of deformation modulations in layered superconductors, and analysis of very long period superstructures. The ordering principles for tetrahedral chains in Ga-, Co-, or Al-substituted YBCO are discussed and their complex defect structures are described. The incommensurate modulation in YBCO-based materials containing SO4-tetrahedra, centered on the Cu(1) sites of the CuO-chain plane, is attributed to the ordering of b-oriented SO4-rich chains in the Cu(1)-S-O layer; the structure is described in terms of an SO4-concentration wave. As examples of the new mercury-based superconducting family we discuss Y0.6Ca0.4Ba2Hg1-xMxCu2O6+y, which crystallizes in the space group P4/mmm with a = 0.3870(1) nm, c = 1.2537(1) nm. This cuprate belongs to the 1212 series; susceptibility measurements show a Tc (onset) of 90K, with a diamagnetic volume fraction of 27% at 4.2K to be reached. A second example is related to the compound Tl2HgBa4Cu2O10+y, in which ordering between single Hg layers and double Tl layers is observed. PMID:7711324

van Tendeloo, G; Krekels, T; Amelinckx, S; Babu, T G; Greaves, C; Hervieu, M; Michel, C; Raveau, B

1995-02-01

185

A simplified method to determine [99mTc]TRODAT-1 in human plasma.  

PubMed

[99mTc]TRODAT-1 is a useful imaging agent in evaluating changes in presynaptic dopamine transporters (DAT) for Parkinson's disease and other central nervous system (CNS) neurodegenerative diseases, for which a reduction of dopamine neurons is indicated. As part of an effort to establish a quantitative single-photon emission tomography (SPECT) procedure for imaging CNS DAT, measurement of nonmetabolized [99mTc]TRODAT-1 in human plasma was investigated. After an intravenous injection of [99mTc]TRODAT-1, there are three possible radioactive components in human plasma: hydrophilic compounds (pertechnetate, etc.), lipophilic metabolite(s), and unchanged [99mTc]TRODAT-1. Based on the differences in lipophilicity of [99mTc]TRODAT-1 and its lipophilic metabolite [99mTc]BAT, a new quantitative method for measuring [99mTc]TRODAT-1 with a simple solvent extraction method was developed. Various organic solvents or mixtures of solvents were tested, among which cyclohexane gave the best extraction yield for [99mTc]TRODAT-1 (76.06 +/- 3.32%) with a low extraction for [99mTc]BAT (2.43 +/- 0.82%). Extractions of [99mTc]TRODAT-1 and [99mTc]BAT mixtures in different predetermined ratios to simulate the actual human plasma samples with cyclohexane from phosphate buffer (5 mM, pH 8.0) were evaluated. The experimentally obtained ratios were in good agreement with the theoretical ratios. To investigate further the possibility of replacing the previously established high performance liquid chromatography (HPLC) method with the new solvent extraction method for the clinical application, both HPLC and extraction methods were used side by side to determine the unchanged [99mTc]TRODAT-1 in human plasma samples during [99mTc]TRODAT-1/SPECT imaging studies. The results from four human subjects showed that both methods consistently produced similar values for unchanged [99mTc]TRODAT-1 in the plasma samples. This improved solvent extraction method provides an easy and reliable technique to quantify unchanged [99mTc]TRODAT-1 in human plasma, thus making the clinical application of this agent readily available for quantitation of the DAT binding sites in the brain by SPECT imaging. PMID:10628563

Mu, M; Kung, M P; Plössl, K; Acton, P D; Mozley, P D; Kung, H F

1999-10-01

186

Radiation-dosimetry and chemical-toxicity considerations for /sup 99/Tc  

SciTech Connect

Technetium-99 (T/sub 1/2/ = 2.13 x 10/sup 5/ y) is produced in the fission of /sup 235/U and /sup 239/Pu. Technitium-99 has been found to contaminate some areas of the uranium re-enrichment process. ICRP-30 Part 2 gives the Annual Limit on Intake (ALI) for /sup 99/Tc as 2 x 10/sup 8/ Bq (5.4 mCi) for class D inhaled material (IC80). The ICRP states clearly that ALIs are based on radiation risk only and that chemical toxicity is not considered (IC79). No data wer found on the chemical toxicity of /sup 99/Tc, possibly because there are no stable isotopes of technetium with which to study the toxicity, although, because of its long T/sub 1/2/, /sup 99/Tc can, for all practical purposes, be considered stable. The ALI values for /sup 99/Tc are based on data obtained using high specific activity /sup 99m/Tc (T/sub 1/2/ = 6 h) and /sup 95m/Tc (T/sub 1/2/ = 61 days). Since the specific activities of /sup 99/Tc and Na/sup 99/TcO/sub 4/ are quite low (17 mCi/g and 9 mCi/g, respectively) and /sup 99/Tc is available in abundant supply, we have attempted to assess the relative radiation and chemical hazards that are associated with this radionuclide. The approach in this study was (1) to study the effect of chemical dose on the whole body retention of /sup 99/Tc sodium pertechnetate in rats and to relate these effects to the radiation dose and the ALI and (2) to compare the chemical toxicity of /sup 99/Tc sodium pertechnetate with the ALI at different chemical dose levels.

Coffey, J.L.; Hayes, R.L.; Rafter, J.J.; Watson, E.E.; Carlton, J.E.

1982-01-01

187

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

188

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

189

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

190

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

SciTech Connect

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

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

1986-09-01

191

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

192

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

193

J Cell Sci . Author manuscript TC10 controls human myofibril organization and is activated by the  

E-print Network

and is activated by the sarcomeric RhoGEF obscurin Marjorie Coisy-Quivy 1 , Olivia Touzet 1 , Annick Bourret 1 obscurin, a sarcomere-associated protein, as a specific activator of TC10. Indeed, TC10 binds directly to obscurin its predicted RhoGEF motif. Importantly, we demonstratevia that obscurin is a specific activator

Boyer, Edmond

194

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

SciTech Connect

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

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

1995-11-01

195

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

E-print Network

is not "TagParser: ISO-TC37 standard conformance" be- cause most of the specifications developed within ISO-TC37 are not ISO standards yet. Let us recall that to be called "standard", a normative ISO document must have the status designated as "In- ternational Standard" with regards to the internal ISO process

Paris-Sud XI, Université de

196

Production of (95m)Tc with the (95)Mo(p,n) reaction.  

National Technical Information Service (NTIS)

The nuclide (sup 95m)Tc(T1/2 = 61d; (gamma)-ray emitter) is an useful isotope as technetium tracer, and its production through the (sup 95)Mo(p,n) reaction has been studied. The formation cross sections of (sup 95m)Tc have been determined for proton energ...

M. Izumo, T. Sorita, H. Matsuoka, Y. Nagame, K. Hata

1990-01-01

197

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

198

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, Turkan; Dogan, Amet Semih; Ulker, Ozden; Durak, Hatice

2014-01-01

199

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

SciTech Connect

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

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

2008-03-15

200

Quark localization in QCD above $T_c$  

E-print Network

It was previously found that at high temperature the lowest part of the QCD Dirac spectrum consists of localized modes obeying Poisson statistics. Higher up in the spectrum, modes become delocalized and their statistics can be described by random matrix theory. The transition from localized to delocalized modes is analogous to the Anderson metal-insulator transition. Here we use dynamical QCD simulations with staggered quarks to study this localization phenomenon. We show that the "mobility edge", separating localized and delocalized modes, scales properly in the continuum limit and rises steeply with the temperature. Using very high statistics simulations in large volumes we find that the density of localized modes scales precisely with the spatial volume and even at $T=2.6T_{c}$ the lowest part of the spectrum extends all the way down to zero with no evidence of a spectral gap.

Matteo Giordano; Tamás G. Kovács; Ferenc Pittler

2013-11-07

201

The first five years of high- Tc superconductivity  

NASA Astrophysics Data System (ADS)

After the 1986 discovery and confirmation of superconductivity in doped La 2CuO 4, a “gold rush” occurred in the following year when the transition temperature in YBa 2Cu 3O 7-? exceeded the boiling point of liquid nitrogen. In 1988, even higher Tc's were reported in new compounds without rare-earth ions. The preparation techniques started to be improved substantially and results on scholarly conducted experiments became available. Since then, the data obtained with different techniques fitted together like pieces of a puzzle, and continue to do so. Early in 1987, high critical magnetic fields and currents were reported in epitaxial films and single crystals. This opened the way for application-oriented research and has led to first true successes in 1990/91. The following is a near verbal transcript of my presentation.

Müller, K. Alex

1991-12-01

202

Anisotropy and impurity effect in high Tc superconductors  

NASA Astrophysics Data System (ADS)

The impurity effect on both superconducting and normal state properties has been investigated to clarify the dimensionality of the one-electron state. Our previous study showed that fully oxidized Ba 2Y(Cu 1-xZn x) 3 O 7-? (BYCZO) shows essentially three-dimensional (3D) behavior. This study extends the work toward more two-dimensional materials, namely oxygen-deficient BYCZO and Bi 2Sr 2Ca(Cu 1-xCo x) 2O 8. The electronic system of the former stays in 3D, while that of the latter behaves essentially in a 2D manner, suggesting that two-dimensionality is irrelevant to high Tc superconductivity.

Matsuda, A.; Semba, K.; Watanabe, T.

1994-12-01

203

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

204

Is there a role for Tc-99m (V) DMSA scintigraphy in ischemic colitis?  

PubMed Central

AIM: To evaluate the role of pentavalent Tc-99m dimercaptosuccinic acid [Tc-99m (V) DMSA] in the diagnosis of ischemic colitis. METHODS: Fourteen patients with endoscopically and histologically confirmed ischemic colitis were included in the study. Tc-99m (V) DMSA scintigraphy was performed within 2 d after colonoscopy. Images were considered positive when an area of increased activity was observed in the region of interest and negative when no abnormal tracer uptake was detected. RESULTS: In 3 out of the 14 patients, Tc-99m (V) DMSA images showed moderate activity in the bowel. The scintigraphic results corresponded with the endoscopic findings. In the other 11 patients, no abnormal tracer uptake was detected in the abdomen. CONCLUSION: Besides the limited number of patients, Tc-99m (V) DMSA could not be considered as a useful imaging modality for the evaluation of ischemic colitis. PMID:18803355

Stathaki, Maria I; Koutroubakis, Ioannis E; Koukouraki, Sophia I; Kouroumalis, Elias A; Karkavitsas, Nikolaos S

2008-01-01

205

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

206

Clinical application of spontaneous red blood cell labeling with Tc-99m sodium pertechnetate.  

PubMed

Red blood cells (RBC) may be labeled with Tc-99m after Tc-99m sodium pertechnetate is injected in the presence of a reducing agent, such as stannous chloride. Thus, spontaneous RBC labeling with Tc-99m is expected to be seen in patients with a high plasma concentration of tin. Spontaneous RBC labeling with Tc-99m was obtained in a 73-year-old woman who was clinically diagnosed with tin intoxication and proved to have a high concentration of plasma tin. The RBC labeling rate was calculated as 96% with blood sampling. Spontaneous RBC labeling with Tc-99m is a very simple method for proving a high plasma tin concentration and is adaptable to clinical diagnosis. PMID:7805326

Kaminaga, T; Nishimura, T; Hayashida, K; Ishida, Y; Hiroki, M

1994-10-01

207

First Report of Human Trypanosoma cruzi Infection Attributed to TcBat Genotype.  

PubMed

Chagas disease is an endemic disease of the American continent caused by Trypanosoma cruzi and divided into six discrete typing units (TcI - TcVI). Nearly 10 million people harbour the infection representing a serious issue in public health. Epidemiological surveillance allowed us to detect a bat-related T. cruzi genotype (henceforth named TcBat) in a 5-year-old female living in a forest area in northwestern Colombia. Molecular tools determined a mixed infection of T. cruzi I and TcBat genotypes. This represents the first report of TcBat infection in humans; the epidemiological consequences of this finding are discussed herein. PMID:25285940

Ramírez, J D; Hernández, C; Montilla, M; Zambrano, P; Flórez, A C; Parra, E; Cucunubá, Z M

2014-11-01

208

Analysis of phonon modes strongly coupled to electrons in high Tc superconducting phases of calcium  

NASA Astrophysics Data System (ADS)

For a zigzag crystal structure of calcium in the phase V, we estimated the superconducting transition temperature Tc by the use of the Allen-Dynes formula. If we set the effective screened Coulomb repulsion constant ?* at 0.1, we obtain Tc=16.37K at 120 GPa and Tc=17.15K at 140 GPa. In order to clarify the origin of such high values of Tc, we analyzed a partial electron-phonon coupling constant at each phonon mode. As the result we found that an optical mode at the G point strongly interacts with electrons and it induces the high Tc in the phase V. The phonon mode can exist only in the particular structure like the zigzag structure.

Ishikawa, T.; Nagara, H.; Kusakabe, K.; Suzuki, N.

2009-03-01

209

Technegas: A medical application of {sup 99m}Tc for the study of buckyballs, blood clots, lung disease and AIDS  

SciTech Connect

Radionuclide studies of lung disease have been greatly enhanced by the introduction of an Australian invention; the Technegas generator. The properties of the {open_quotes}dry radio-aerosols{close_quotes} produced by this device ensure lung images superior to those from true radio-gases such as {sup 133}Xe with the additional advantage of employing {sup 99m}Tc, the most widespread radionuclide agent. A Technegas lung scan can enable identification of pulmonary mebolism (an immediately life threatening condition) emphysema and chronic obstructive lung disease. A simple modification to the generator gas mixture produces Pertechnegas an agent useful in studies of the integrity of the alveolar epithelial membrane in immunosuppressed patients such as transplants and AIDS. Although these agents are now common in Australia and Europe, little has been proven of their chemical composites. Technegas is formed by the initial evaporation of ({sup 99m}Tc) sodium pertechnetate with the subsequent sublimation of carbon from a disposable graphite crucible at {approximately}2500{degrees}C in an atmosphere of 100% argon. {sup 99m}Tc atoms are lifted off with the crystalline layers of graphite during the vaporization. Technegas then possibly consists of {sup 99m}Tc based metallo-fullerenes and fullerenes. Technegas has an effective half life in the lung very similar to the physical half life of Technetium (6 hours) regardless of clinical condition; a result which suggests that Technegas contains endohedral fullerenes. Pertechnegas is created in an atmosphere of 97% Ar 3% O{sub 2} and has an effective half life in the lung of less than 15 minutes.

Willett, G.D.; Dance, I.G.; Fisher, K.J. [Univ. of NSW, Sidney (Australia); Burch, W.M.; Dasaklis, C. [Australian National Univ., Canberra (Australia); Mackey, D.W.J. [Prince of Wales Hospital, Randwick (Australia)

1994-12-31

210

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

211

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

PubMed

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

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

2013-01-01

212

The recovery of asteroid 2008 TC[subscript 3  

SciTech Connect

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

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

2011-09-06

213

Cryogenic load calculation of high Tc current lead  

NASA Astrophysics Data System (ADS)

High temperature superconducting current leads are composed of a normal metal part, conducting the current from room temperature to an intermediate temperature (often 77 K), and a high Tc part, conducting the current down to liquid helium temperature. The cryogenic load and the corresponding power consumption of both parts are compared to the electrical power consumption of an equivalent all metal current lead. The temperature profiles and the 4.2 K heat load of the superconducting part are evaluated by a computer calculation. The calculation uses material parameters from sintered Y-123 and melt-cast processed Bi-2212 tubes, materials which already exist in usable dimensions for current leads. The 1 ?V cm -1 criterion turns out to be much too conservative and some dissipation due to flux flow in the upper part of the lead does not affect the overall performance of the current lead if the thermal runaway current ITR is not exceeded. The maximum stable current is evaluated as a function of conductor length for operation in a self-field and applied fields up to 0.2 T. Long leads result in very low 4.2 K heat loads but shorter leads result in higher stable transport currents. The use of very short high Tc conductor parts (50 mm) and the possibility of fabricating a short metallic lead for 77 K operation allows us to design very short (< 0.3 m) and high performance current leads for 4.2 K applications. This current lead can be designed to pass right through the insulating vacuum of a cryostat, presenting new opportunities for a more compact cryostat system. Stability considerations indicate that the current lead is not sensitivie to flux jumps. As currents I > ITR cannot be accepted, a safety margin must be considered in the design of the current lead.

Herrmann, P. F.; Cottevieille, C.; Duperray, G.; Leriche, A.; Verhaege, T.; Albrecht, C.; Bock, J.

214

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

215

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

216

78 FR 30269 - Foreign-Trade Zone 129-Bellingham, Washington; Authorization of Production Activity; T.C. Trading...  

Federal Register 2010, 2011, 2012, 2013

...Bellingham, Washington; Authorization of Production Activity; T.C. Trading Company, Inc. (Eyeglass Assembly and Kitting...activity to the Foreign-Trade Zones (FTZ) Board on behalf of T.C. Trading Company, Inc., within Subzone 129B, in...

2013-05-22

217

Recombinant Complement Receptor 2 Radiolabeled with [99mTc(CO)3]+ : A Potential New Radiopharmaceutical for Imaging Activated Complement  

PubMed Central

We describe the design and synthesis of a new Tc-99m labeled bioconjugate for imaging activated complement, based on Short Consensus Repeats 1 and 2 of Complement Receptor 2 (CR2), the binding domain for C3d. To avoid non specific modification of CR2 and the potential for modifying lysine residues critical to the CR2/C3d contact surface, we engineered a new protein, recombinant CR2 (rCR2), to include the C-terminal sequence VFPLECHHHHHH, a hexahistidine tag (for site-specific radiolabeling with [99mTc(CO)3(OH2)3]+). The protein was characterized by N-terminal sequencing, SDS-PAGE and size exclusion chromatography. To test the function of the recombinant CR2, binding to C3d was confirmed by enzyme-linked immunosorbent assay (ELISA). The function was further confirmed by binding of rCR2 to C3d+ red blood cells (RBC) which were generated by deposition of human or rat C3d and analyzed by fluorescence microscopy and flow cytometry. The affinity of rCR2 for C3d+, in presence of 150 mM NaCl, was measured using surface plasma resonance giving rise to a KD?500 nM. Radiolabeling of rCR2 or an inactive mutant of rCR2 (K41E CR2) or an unrelated protein of a similar size (C2A) with [99mTc(CO)3(OH2)3]+ at gave radiochemical yields >95%. Site-specifically radiolabeled rCR2 bound to C3d to C3d+ RBC. Binding of radiolabeled rCR2 to C3d was inhibited by anti-C3d and the radiolabeled inactive mutant K41E CR2 and C2A did not bind to C3d+ RBCs. We conclude that rCR2-Tc99m has excellent radiolabeling, stability and C3d binding characteristics and warrants in vivo evaluation as an activated complement imaging agent. PMID:21494666

McDonnell, James M.; Yahya, Norhakim; Thakor, David; Razavi, Reza; Smith, Richard; Sacks, Steven; Mullen, Gregory E. D.

2011-01-01

218

Thinking generations.  

PubMed

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

White, Jonathan

2013-06-01

219

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

220

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

221

1. Generation 1 1. Generation  

E-print Network

the generating mechanism itself the source, in the fluid acoustic case. This means that in contrast to structural acoustics , it is sometimes in fluid acoustics more tractable to treat the generating mechanism directly. With respect to fluid acoustic sources the situation is slightly different. In some cases these sources

Berlin,Technische Universität

222

Function Generator / Arbitrary Waveform Generator  

E-print Network

of bench-top and system features makes this function generator a versatile solution for your testing MENU 1: OUT TERM 2: POWER ON 3: ERROR 4: TEST 5: COMMA 6: REVISION F: CALibration MENU* 1: SECURED or talk over a remote interface. Function generator is in remote mode (remote interface). Function

King, Roger

223

Competitive Reduction of Pertechnetate (99TcO4?) by Dissimilatory Metal Reducing Bacteria and Biogenic Fe(II)  

SciTech Connect

The fate of pertechnetate (99Tc(VII)O4 -) during bioreduction was investigated in the presence of 2-line ferrihydrite (Fh) and various dissimilatory metal reducing bacteria (DMRB) (Geobacter, Anaeromyxobacter, Shewanella) in comparison with TcO4 - bioreduction in the absence of Fh. In the presence of Fh, Tc was present primarily as a fine-grained Tc(IV)/Fe precipitate that was distinct from the Tc(IV)O2 ·nH2O solids produced by direct biological Tc(VII) reduction. Aqueous Tc concentrations (<0.2 ?m) in the bioreduced Fh suspensions (1.7 to 3.2 × 10-9 mol L-1) were over 1 order of magnitude lower than when TcO4 - was biologically reduced in the absence of Fh (4.0 × 10-8 to 1.0 × 10-7 mol L-1). EXAFS analyses of the bioreduced Fh-Tc products were consistent with variable chain length Tc-O octahedra bonded to Fe-O octahedra associated with the surface of the residual or secondary Fe(III) oxide. In contrast, biogenic TcO2 ·nH2O had significantly more Tc-Tc second neighbors and a distinct long-range order consistent with small particle polymers of TcO2. In Fe-rich subsurface sediments, the reduction of Tc(VII) by Fe(II) may predominate over direct microbial pathways, potentially leading to lower concentrations of aqueous 99Tc(IV).

Plymale, Andrew E.; Fredrickson, Jim K.; Zachara, John M.; Dohnalkova, Alice; Heald, Steve M.; Moore, Dean A.; Kennedy, David W.; Marshall, Matthew J.; Wang, Chong M.; Resch, Charles T.; Nachimuthu, Ponnusamy

2011-02-01

224

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

SciTech Connect

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

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

1983-03-01

225

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

226

Generation Wrecked.  

ERIC Educational Resources Information Center

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

Watson, Noshua

2002-01-01

227

Spray Generation.  

National Technical Information Service (NTIS)

This is an experimental investigation of the ligaments and drops generated at the free surface of liquid wall jets and liquid axisymmetric jets flowing over sand and polystyrene (beads) roughed surfaces. Experiments were conducted with freshwater and Eule...

A. G. Salinas

1999-01-01

228

Hydrogen Generator  

NASA Technical Reports Server (NTRS)

A unit for producing hydrogen on site is used by a New Jersey Electric Company. The hydrogen is used as a coolant for the station's large generator; on-site production eliminates the need for weekly hydrogen deliveries. High purity hydrogen is generated by water electrolysis. The electrolyte is solid plastic and the control system is electronic. The technology was originally developed for the Gemini spacecraft.

1983-01-01

229

Generation Activities  

NSDL National Science Digital Library

This page presents activities related to the generation of electrical power from the Science & Engineering in the Lives of Students project. Activities include Battery & Wire Motor, Examine Transformers, Magnet & Coil, Measuring Work, Potato Halo, Two Generators, Voltmeter and a Bulb and Wire Around Compass. Each activity includes a description, list of the materials needed and science concepts covered. Several activities include videos, diagrams or links to other supporting materials.

2013-08-14

230

Vibration generators  

SciTech Connect

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

Lerwill, W.E.

1980-09-16

231

Phase transitions in high-Tc superconductors and the anisotropic three-dimensional XY model Tao Chen and S. Teitel  

E-print Network

- ture Tm well below the mean field Tc2 which marks the onset of strong diamagnetism.4,5 In between Tm by the observation that, in high-Tc materials, the onset of reversible diamagnetism occurs at a temperature well with increasing H. Ac- cording to this picture, the onset of diamagnetism at Tc2 is associated with a growth

Teitel, Stephen L.

232

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

233

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

PubMed Central

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. 99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, 99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of 99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, 99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing 99mTc-tilmanocept with other 99mTc-based agents are required before it can be routinely used in clinical settings. PMID:25028560

Tausch, Christoph; Baege, Astrid; Rageth, Christoph

2014-01-01

234

[Comparison of migration characteristic of 3H and 99Tc in loess].  

PubMed

3H and 99Tc are important nuclides in low and intermediate level radioactive wastes, and in safety assessment of near surface repository their migration characteristic usually determines the computing result. The medium of loess appears to possess the characteristic of weak adsorption ability to 3H and 99Tc when they are migrating in it, so the adsorption ability are often neglected, and 3H are used to identify groundwater velocity. But in the field test it was showed that in the aerated zone loess possesses stronger adsorption ability to 99Tc than to 3H, and in the aquifer the stronger adsorption ability to 3H than to 99Tc. In this paper the migration tests of 3H and 99Tc were simulated by NESOR program of non-equilibrium adsorption model. The results show: 99Tc distribution coefficient ranges 0.05-0.055 mL/g in the aerated zone, 3H distribution coefficient is 0.116 mL/g in the aquifer, and the parameter reflects integrated impact of loess on 3H and 99Tc, and the mechanism of them being retarded still need proving. PMID:14768564

Wang, Jinsheng; Guo, Minli; Liu, Chunli; Li, Shushen

2003-11-01

235

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

PubMed

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

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

2004-12-01

236

Assessment of the effect of Punica granatum (pomegranata) on the bioavailability of the radiopharmaceutical sodium pertechnetate (99mTc) in Wistar rats.  

PubMed

The many desirable characteristics of technetium-99m (99mTc) have stimulated the development of labeling techniques for different molecular and cellular structures. It is generally accepted that a variety of factors other than disease can alter the bioavailability of radiopharmaceuticals and one such factor is the drug therapy. The use of medicinal plants has increased in the last decades all over the world. Punica granatum (pomegranata) is used as food or as medication in folk medicine for antiviral, anthelmintic, antifungal, antibacterial and antimicrobial activity. We have studied in rats, the effect of the medicinal plant Punica granatum on the bioavailability of the radiopharmaceutical 99mTc-sodium pertechnetate (Na(99m)TcO4). The infusion of pomegranata was administered by intragastric via into Wistar rats during seven days. After that, the animals received by ocular plexus via, 0.1 ml of the Na(99m)TcO4 (3.7MBq) and the animals were rapidly sacrificed after 5, 20 and 40 min. The organs were isolated (brain, heart, thyroid, liver, lungs, kidneys, stomach, testis, intestines, pancreas, spleen, bladder, muscle and bone), the radioactivity determined in a well counter, the percentages of radioactivity (%ATI) in the organs were calculated and statistical analyses were performed by Wilcoxon test (p < 0.05). The results have shown a significant (p < 0.05) increase of the activity of the Na(99m)TcO4 in spleen, heart, stomach, liver, stout bowel, pancreas, lungs and testis at 5 min. Twenty minutes after the administration of the radiopharmaceutical, the analysis of the results reveals a significant (p < 0.05) increase of the %ATI in heart, stomach, femur, pancreas, lungs and kidneys. Forty minutes after the administration of the Na(99m)TcO4, the results show a significant (p < 0.05) increase in spleen, brain, heart, stomach, liver, stout bowel, muscle, femur, lungs, pancreas, kidneys and testis. These results can be justified by therapeutic effect of this extract and/or by generation of active metabolites capable to interfere with the biodistribution of the studied radiopharmaceutical. PMID:12899440

Amorim, L F; Catanho, M T J A; Terra, D A; Brandão, K C; Holanda, C M C X; Jales-Júnior, L H; Brito, L M L; Gomes, M L; De Melo, V G B; Bernardo-Filho, M; Cavalcanti Jales, R L

2003-06-01

237

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

238

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

239

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

240

99mTc(CO)3(NTA): A 99mTc Renal Tracer with Pharmacokinetic Properties Comparable to Those of 131I-OIH in Healthy Volunteers  

PubMed Central

Objectives Studies in rats showed that the pharmacokinetics of the tricarbonyl core radiopharmaceutical 99mTc(CO)3-nitrilotriacetic acid, 99mTc(CO)3(NTA), were essentially identical to those of 131I ortho-iodohippuran (131I-OIH), the clinical gold standard for the measurement of effective renal plasma flow. Our objective was to compare the pharmacokinetics of these two tracers in healthy volunteers. Methods 99mTc(CO)3(NTA) was prepared with commercially available NTA and a commercially available IsoLink kit (Covidien) and isolated by reversed-phased high-performance liquid chromatography. Approximately 74 MBq (2.0 mCi) of 99mTc(CO)3(NTA) were coinjected with 9.25 MBq (250 ?Ci) of 131I-OIH in nine volunteers, and simultaneous imaging of each tracer was performed for 24 min. Plasma clearances were determined from 8 blood samples obtained 3–90 min after injection using the single-injection, two-compartment model. Plasma protein binding, red cell uptake, and percentage injected dose in the urine at 30 and 180 minutes were determined. Results There was no difference in the plasma clearances of 99mTc(CO)3(NTA) and 131I-OIH, 475 ± 105 mL/min versus 472 ± 108 mL/min, respectively. The plasma protein binding and red cell uptake of 99mTc(CO)3(NTA) were 43 ± 5% and 9 ± 6%, respectively; both values were significantly lower (P < 0.001) than the plasma protein binding (75 ± 3%) and red cell uptake (17 ± 5%) of 131I-OIH. There was no significant difference in the percent injected dose recovered in the urine at 30 min and at 3 h; for comparison, the percent dose in the urine at 3 h was 91 ± 4% for 99mTc(CO)3(NTA) and 91 ± 6% for 131I-OIH (P = 0.96). Image quality with 99mTc(CO)3(NTA) was excellent, and the renogram parameters were similar to those of 131I-OIH. Conclusions Preliminary results in healthy volunteers suggest that the pharmacokinetic behavior of 99mTc(CO)3(NTA) is comparable to that of 131I-OIH. PMID:20150248

Taylor, Andrew T.; Lipowska, Malgorzata; Marzilli, Luigi G.

2010-01-01

241

KEY COMPARISON Activity measurements of the radionuclide 99mTc for the NIST, USA in the ongoing comparison BIPM.RI(II)-K4.Tc-99m  

NASA Astrophysics Data System (ADS)

In 2009, the first comparison of activity measurements of 99mTc using the Transfer Instrument of the International Reference System (SIRTI) took place at the National Institute of Standards and Technology (NIST), USA. An ampoule containing about 30 kBq of 99mTc traceable to the NIST primary standard was measured in the SIRTI for more than three half-lives. The influence of the 99Mo impurity was negligible. The comparison, identifier BIPM.RI(II)-K4.Tc-99m, is linked to the BIPM.RI(II)-K1.Tc-99m comparison, and the degrees of equivalence with the key comparison reference value and between the present NIST result and the six participants in the K1 comparison have been evaluated. Consistency between the USA and European activity measurements of 99mTc is demonstrated. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Michotte, C.; Fitzgerald, R.

2010-01-01

242

??mTc carbonyl DTPA-rituximab: preparation and preliminary bioevaluation.  

PubMed

The anti CD20 antibody Rituximab was conjugated with para isothiocyanato benzyl diethylene triamine penta acetic acid (p-NCS-Bz-DTPA) and subsequent radiolabeling with (99m)Tc was carried out via the (99m)Tc carbonyl synthon. The (99m)Tc labeled antibody conjugate exhibited >95% radiochemical purity after purification and retained good in vitro stability when studied up to 24h at room temperature. In vitro cell binding studies carried out in Raji cells expressing CD20 antigen validated the biological efficacy of the preparation. PMID:24486518

Pandey, Usha; Kameswaran, Mythili; Dev Sarma, Haladhar; Samuel, Grace

2014-04-01

243

/sup 99m/Tc-aprotinin: A new tracer for kidney morphology and function  

SciTech Connect

Aprotinin (Ap), a low molecular weight polyeptide (6500 dalton), is a protease inhibitor which is electively and stably accumulated in the kidney. In 112 adult patients, with either uni- or bilateral renal disease with different degrees of renal impairment (from normal GFR to advanced renal failure), renal scans were performed by means of Ap labelled with /sup 99m/Tc. Highly satisfactory renal scans were obtained in all patients. In 20 patients with renal failure (serum creatinine 1.8 - 8.5 mg/dl, mean 4.7) a comparison was made of the renal scans obtained with /sup 99m/Tc-Ap and with /sup 99m/Tc-DMSA. /sup 99m/Tc-Ap was slightly better than /sup 99m/Tc-DMSA, especially in patients with far advanced renal failure. Some aspects of the pharmacokinetics of /sup 99m/Tc-Ap were studied in 72 cases. In 22 of these patients plasma clearance of /sup 99m/Tc-Ap was determined by the single injection method using a two-compartment model. In patients with GFR>90 ml/min plasma cl of /sup 99m/Tc-Ap was 67.6 +- 8.4 SD ml/min. A good correlation was observed between plasma clearance of /sup 99m/Tc-Ap and GFR (r = 0.74). After i.v. injection /sup 99m/Tc-Ap was stably fixed by the kidney. Renal radioactivity remained stable between the 2nd and the 8th hour after the injection. Urinary excretion of radioactivity measured in 35 patients in the first and in the second 2-hour interval after i.v. injection of /sup 99m/Tc-Ap was negligible in all patients (2.7 +- 1.5 SD percent of the dose in the fist 2 hours; 2.8 +- 1.4 SD between the 2nd and the 4th hour). Conclusions. /sup 99m/Tc-Ap is an excellent agent for renal imaging. It also seems promising for renal function studies.

Bianchi, C.; Donadio, C.; Tramonti, G.; Lorusso, P.; Bellitto, L.; Lunghi, F.

1984-01-01

244

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

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

245

A conveniently prepared Tc-99m resin for semisolid gastric emptying studies  

SciTech Connect

A polystyrene resin, suitable for semi-solid gastric emptying studies, was rapidly (less than 20 min) and conveniently prepared using commercially available reagents. Using the outlined procedure, Chelex-100 resin bound Tc-99m with greater than 98% labeling efficiency. The resulting Tc-99m Chelex-100 resin demonstrated excellent in vitro and in vivo stability. The clinical application of Tc-99m Chelex-100 resin, mixed with oatmeal, was tested in normal subjects and in various patient groups, including diabetic autonomic neuropathy, pyloric obstruction, postoperative dumping syndrome, and morbidly obese patients before and after gastroplasty.

Wirth, N.; Swanson, D.; Shapiro, B.; Nakajo, M.; Coffey, J.L.; Eckhauser, F.; Owyang, C.

1983-06-01

246

Conveniently prepared Tc-99m resin for semisolid gastric emptying studies  

SciTech Connect

A polystyrene resin, suitable for semi-solid gastric emptying studies, was rapidly (<20 min) and coveniently prepared using commercially available reagents. Using the outlined procedure, Chelex-100 resin bound Tc-99m with greater than 98% labeling efficiency. The resulting Tc-99m Chelex-100 resin demonstrated excellent in vitro and in vivo stability. The clinical application of Tc-99m Chelex-100 resin, mixed with oatmeal, was tested in normal subjects and in various patient groups, including diabetic autonomic neuropathy, pyloric obstruction, postoperative dumping syndrome, and morbidly obese patients before and after gastroplasty.

Wirth, N. (Univ. of Michigan, Ann Arbor); Shapiro, B.; Nakajo, M.; Coffey, J.L.; Eckhauser, F.; Owyang, C.

1983-06-01

247

High pressure effects on high Tc superconductivity: the enhancement of superconducting transition temperature by ordering  

NASA Astrophysics Data System (ADS)

We discussed the high pressure improvement on superconducting transition temperature (Tc) related to the ordering at the apical oxygen layer of a high temperature superconductor (HTS). This study became available in the high pressure synthesized Sr2CuO3+? superconductor with K2NiF4 structure showing so far rarely formed partially occupied apical oxygen which also act as the dopant of the HTS. The well-defined links between Tc and modulated structures suggests that optimizing the ordering at apical oxygen layer outside CuO2 plane is a promising way to further enhance Tc.

Liu, Q. Q.; Yang, H.; Yang, L. X.; Yu, Y.; Gao, W. B.; Li, F. Y.; Yu, R. C.; Jin, C. Q.; Uchida, S.

2008-07-01

248

Foam as a Delivery Vehicle in Vadose Zone Remediation: Transport; Amendment Distribution; and Tc-99 Immobilization  

NASA Astrophysics Data System (ADS)

Foam is a promising low water content advection technology for the distribution of remedial amendments to the deep vadose zone for metals and radionuclides remediation. Foam flow in the vadose zone can be directed by manipulating the pressure field, therefore the foam delivery technology allows more even distribution of remedial amendments under vadose zone conditions than water-based delivery. With minimal water content in foam flow, foam delivery minimizes the potential for contaminant mobilization and spreading. Laboratory scale experiments were conducted to investigate the physical aspects of foam transport in sediments under vadose zone conditions, to study the (poly)phosphate amendment foam-delivery; and to evaluate technetium-99 immobilization by foam-delivered calcium polysulfide. Foam quality (percentage of gas volume in total foam volume) between 95% and 99% was tested to study its influence on foam injection pressure. It was observed that the injection pressure increased inversely as a function of foam quality. The effect of sediment permeability on foam injection pressure was evaluated in sediments with a range of permeabilities. Results suggested that when the foam injection rate was low, the injection pressure increased with sediment permeability; but when the foam injection rate was high, the injection pressure versus permeability relationship was reversed. Foam bubbles rupture at the foam-flow-front in the unsaturated sediments. The front of the gas injected with foam traveled significantly faster (~ 8 times) than the foam front observed in the sediment. The liquid carried by foam was left behind the foam front. In addition a water accumulation front developed in sediment ahead of the foam-flow-front, i.e. sediment not swept by foam flow, as native pore water was displaced by the foam front. The water content in this liquid accumulation front increased with the increasing of initial water content in the sediment. However, the water content in the sediment swept by foam flow was negligibly affected by the initial water content. Very low surfactant concentration was observed in the accumulated liquid ahead of the foam front, indicating the initial moisture in the sediment was pushed forward by foam flow. In the foam-delivery of (poly)phosphate column tests, the delivery of phosphate was retarded slightly compare to the foam front and the distribution of surfactant in the sediment. The profile of pore water electric conductivity was similar to the phosphate distribution profile. Immobilization of Tc-99 by foam-delivered calcium polysulfide (CPS) in sediments under vadose zone conditions was evaluated. Foams generated from 0.5 wt% STEOL CS-330 surfactant solution at quality of 98% was used to deliver CPS sediment in columns for reductive immobilization of Tc-99. The foaming solution contained 5 wt% of calcium polysulfide. Using the foam-delivered calcium polysulfide, 66% of the total Tc-99 in the contaminated sediment was immobilized in the sediment. No technetium remobilization was observed when up to 6 pore volume of synthetic ground water was flushed through the treated sediment column.

Zhong, L.; Szecsody, J.; Wellman, D. M.; Zhang, Z. F.; Mattigod, S.; Pierce, E. M.

2009-12-01

249

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

250

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, Andre; Audenaert, Kurt; Eersels, Jos; Vermeire, Simon; De Spiegeleer, Bart; Polis, Ingeborgh

2014-01-01

251

Fast Monte Carlo based joint iterative reconstruction for simultaneous {sup 99m}Tc/{sup 123}I SPECT imaging  

SciTech Connect

Simultaneous {sup 99m}Tc/{sup 123}I SPECT allows the assessment of two physiological functions under identical conditions. The separation of these radionuclides is difficult, however, because their energies are close. Most energy-window-based scatter correction methods do not fully model either physical factors or patient-specific activity and attenuation distributions. We have developed a fast Monte Carlo (MC) simulation-based multiple-radionuclide and multiple-energy joint ordered-subset expectation-maximization (JOSEM) iterative reconstruction algorithm, MC-JOSEM. MC-JOSEM simultaneously corrects for scatter and cross talk as well as detector response within the reconstruction algorithm. We evaluated MC-JOSEM for simultaneous brain profusion ({sup 99m}Tc-HMPAO) and neurotransmission ({sup 123}I-altropane) SPECT. MC simulations of {sup 99m}Tc and {sup 123}I studies were generated separately and then combined to mimic simultaneous {sup 99m}Tc/{sup 123}I SPECT. All the details of photon transport through the brain, the collimator, and detector, including Compton and coherent scatter, septal penetration, and backscatter from components behind the crystal, were modeled. We reconstructed images from simultaneous dual-radionuclide projections in three ways. First, we reconstructed the photopeak-energy-window projections (with an asymmetric energy window for {sup 123}I) using the standard ordered-subsets expectation-maximization algorithm (NSC-OSEM). Second, we used standard OSEM to reconstruct {sup 99m}Tc photopeak-energy-window projections, while including an estimate of scatter from a Compton-scatter energy window (SC-OSEM). Third, we jointly reconstructed both {sup 99m}Tc and {sup 123}I images using projection data associated with two photopeak energy windows and an intermediate-energy window using MC-JOSEM. For 15 iterations of reconstruction, the bias and standard deviation of {sup 99m}Tc activity estimates in several brain structures were calculated for NSC-OSEM, SC-OSEM, and MC-JOSEM, using images reconstructed from primary (unscattered) photons as a reference. Similar calculations were performed for {sup 123}I images for NSC-OSEM and MC-JOSEM. For {sup 123}I images, dopamine binding potential (BP) at equilibrium and its signal-to-noise ratio (SNR) were also calculated. Our results demonstrate that MC-JOSEM performs better than NSC- and SC-OSEM for quantitation tasks. After 15 iterations of reconstruction, the relative bias of {sup 99m}Tc activity estimates in the thalamus, striata, white matter, and gray matter volumes from MC-JOSEM ranged from -2.4% to 1.2%, while the same estimates for NSC-OSEM (SC-OSEM) ranged from 20.8% to 103.6% (7.2% to 41.9%). Similarly, the relative bias of {sup 123}I activity estimates from 15 iterations of MC-JOSEM in the striata and background ranged from -1.4% to 2.9%, while the same estimates for NSC-OSEM ranged from 1.6% to 10.0%. The relative standard deviation of {sup 99m}Tc activity estimates from MC-JOSEM ranged from 1.1% to 4.8% versus 1.2% to 6.7% (1.2% to 5.9%) for NSC-OSEM (SC-OSEM). The relative standard deviation of {sup 123}I activity estimates using MC-JOSEM ranged from 1.1% to 1.9% versus 1.5% to 2.7% for NSC-OSEM. Using the {sup 123}I dopamine BP obtained from the reconstruction produced by primary photons as a reference, the result for MC-JOSEM was 50.5% closer to the reference than that of NSC-OSEM after 15 iterations. The SNR for dopamine BP was 23.6 for MC-JOSEM as compared to 18.3 for NSC-OSEM.

Ouyang Jinsong; El Fakhri, Georges; Moore, Stephen C. [Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115 (United States)

2007-08-15

252

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

253

99mTc Pyrene Derivative Complex Causes Double-Strand Breaks in dsDNA Mainly through Cluster-Mediated Indirect Effect in Aqueous Solution.  

PubMed

Radiation therapy for cancer patients works by ionizing damage to nuclear DNA, primarily by creating double-strand breaks (DSB). A major shortcoming of traditional radiation therapy is the set of side effect associated with its long-range interaction with nearby tissues. Low-energy Auger electrons have the advantage of an extremely short effective range, minimizing damage to healthy tissue. Consequently, the isotope 99mTc, an Auger electron source, is currently being studied for its beneficial potential in cancer treatment. We examined the dose effect of a pyrene derivative 99mTc complex on plasmid DNA by using gel electrophoresis in both aqueous and methanol solutions. In aqueous solutions, the average yield per decay for double-strand breaks is 0.011±0.005 at low dose range, decreasing to 0.0005±0.0003 in the presence of 1 M dimethyl sulfoxide (DMSO). The apparent yield per decay for single-strand breaks (SSB) is 0.04±0.02, decreasing to approximately a fifth with 1 M DMSO. In methanol, the average yield per decay of DSB is 0.54±0.06 and drops to undetectable levels in 2 M DMSO. The SSB yield per decay is 7.2±0.2, changing to 0.4±0.2 in the presence of 2 M DMSO. The 95% decrease in the yield of DSB in DMSO indicates that the main mechanism for DSB formation is through indirect effect, possibly by cooperative binding or clustering of intercalators. In the presence of non-radioactive ligands at a near saturation concentration, where radioactive Tc compounds do not form large clusters, the yield of SSB stays the same while the yield of DSB decreases to the value in DMSO. DSBs generated by 99mTc conjugated to intercalators are primarily caused by indirect effects through clustering. PMID:25244160

Chung, Wei-Ju; Cui, Yujia; Huang, Feng-Yun J; Tu, Tzu-Hui; Yang, Tzu-Sen; Lo, Jem-Mau; Chiang, Chi-Shiun; Hsu, Ian C

2014-01-01

254

99mTc Pyrene Derivative Complex Causes Double-Strand Breaks in dsDNA Mainly through Cluster-Mediated Indirect Effect in Aqueous Solution  

PubMed Central

Radiation therapy for cancer patients works by ionizing damage to nuclear DNA, primarily by creating double-strand breaks (DSB). A major shortcoming of traditional radiation therapy is the set of side effect associated with its long-range interaction with nearby tissues. Low-energy Auger electrons have the advantage of an extremely short effective range, minimizing damage to healthy tissue. Consequently, the isotope 99mTc, an Auger electron source, is currently being studied for its beneficial potential in cancer treatment. We examined the dose effect of a pyrene derivative 99mTc complex on plasmid DNA by using gel electrophoresis in both aqueous and methanol solutions. In aqueous solutions, the average yield per decay for double-strand breaks is 0.011±0.005 at low dose range, decreasing to 0.0005±0.0003 in the presence of 1 M dimethyl sulfoxide (DMSO). The apparent yield per decay for single-strand breaks (SSB) is 0.04±0.02, decreasing to approximately a fifth with 1 M DMSO. In methanol, the average yield per decay of DSB is 0.54±0.06 and drops to undetectable levels in 2 M DMSO. The SSB yield per decay is 7.2±0.2, changing to 0.4±0.2 in the presence of 2 M DMSO. The 95% decrease in the yield of DSB in DMSO indicates that the main mechanism for DSB formation is through indirect effect, possibly by cooperative binding or clustering of intercalators. In the presence of non-radioactive ligands at a near saturation concentration, where radioactive Tc compounds do not form large clusters, the yield of SSB stays the same while the yield of DSB decreases to the value in DMSO. DSBs generated by 99mTc conjugated to intercalators are primarily caused by indirect effects through clustering. PMID:25244160

Chung, Wei-Ju; Cui, Yujia; Huang, Feng-Yun J.; Tu, Tzu-Hui; Yang, Tzu-Sen; Lo, Jem-Mau; Chiang, Chi-Shiun; Hsu, Ian C.

2014-01-01

255

High-Tc superconducting microbolometer for terahertz applications  

NASA Astrophysics Data System (ADS)

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

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

2002-05-01

256

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

257

Dynamic resistance of a high-Tc superconducting flux pump  

NASA Astrophysics Data System (ADS)

Superconducting flux pumps enable large currents to be injected into a superconducting circuit, without the requirement for thermally conducting current leads which bridge between the cryogenic environment and room temperature. In this work, we have built and studied a mechanically rotating flux pump which employs a coated conductor high-Tc superconducting (HTS) stator. This flux pump has been used to excite an HTS double pancake coil at 77 K. Operation of the flux pump causes the current within the superconducting circuit to increase over time, before saturating at a limiting value. Interestingly, the superconducting flux pump is found to possess an effective internal resistance, Reff, which varies linearly with frequency, and is two orders of magnitude larger than the measured series resistance of the soldered contacts within the circuit. This internal resistance sets a limit for the maximum achievable output current from the flux pump, which is independent of the operating frequency. We attribute this effect to dynamic resistance within the superconducting stator wire which is caused by the interaction between the DC transport current and the imposed alternating magnetic field. We provide an analytical expression describing the output characteristics of our rotating flux pump in the high frequency limit, and demonstrate that it describes the time-dependent behavior of our experimental circuit. Dynamic resistance is highlighted as a generic issue that must be considered when optimizing the design of an HTS flux pump.

Jiang, Zhenan; Hamilton, K.; Amemiya, Naoyuki; Badcock, R. A.; Bumby, C. W.

2014-09-01

258

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

259

Advances in High-Tc Single Flux Quantum Device Technologies  

NASA Astrophysics Data System (ADS)

We have developed the fabrication process, the circuit design technology, and the cryopackaging technology for high-Tc single flux quantum (SFQ) devices with the aim of application to an analog-to-digital (A/D) converter circuit for future wireless communication and a sampler system for high-speed measurements. Reproducibility of fabricating rampedge Josephson junctions with IcRn products above 1mV at 40K and small Ic spreads on a superconducting groundplane was much improved by employing smooth multilayer structures and optimizing the junction fabrication process. The separated base-electrode layout (SBL) method that suppresses the Jc spread for interface-modified junctions in circuits was developed. This method enabled low-frequency logic operations of various elementary SFQ circuits with relatively wide bias current margins and operation of a toggle-flip-flop (T-FF) above 200GHz at 40K. Operation of a 1:2 demultiplexer, one of main elements of a hybrid-type ?-? A/D converter circuit, was also demonstrated. We developed a sampler system in which a sampler circuit with a potential bandwidth over 100GHz was cooled by a compact stirling cooler, and waveform observation experiments confirmed the actual system bandwidth well over 50GHz.

Tanabe, Keiichi; Wakana, Hironori; Tsubone, Koji; Tarutani, Yoshinobu; Adachi, Seiji; Ishimaru, Yoshihiro; Maruyama, Michitaka; Hato, Tsunehiro; Yoshida, Akira; Suzuki, Hideo

260

Identification of the ? transitions in Tc and Cs products of 252Cf fission and possible 7/2+ [413] bands in 105-109Tc isotopes  

NASA Astrophysics Data System (ADS)

Several ? transitions in 105-109Tc nuclei were identified for the first time from spontaneous fission studies with a 252Cf source and the Gammasphere. New level schemes are proposed and related to the underlying nuclear structure. Positive parity bands with a large signature splitting observed in 105,107,109Tc are evidently derived from g9/2 orbitals and are similar to analogous bands in 103Rh,103Ag, and 99Y. New ? transitions have also been identified in 139-143Cs and used to construct level schemes for these isotopes. Correlated-pair fission yields extracted from the data show an appreciable field for the zero neutron 109Tc/143Cs pair.

Hwang, J. K.; Ramayya, A. V.; Hamilton, J. H.; Peker, L. K.; Kormicki, J.; Babu, B. R.; Ginter, T. N.; Beyer, C. J.; Rasmussen, J. O.; Gilat, J.; Asztalos, S. J.; Chu, S. Y.; Gregorich, K. E.; Macchiavelli, A. O.; MacLeod, R. W.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.; Daniel, A. V.; Ma, W. C.; Varmette, P. G.; Cole, J. D.; Aryaeinejad, R.; Butler-Moore, K.; Drigert, M. W.; Stoyer, M. A.; Bernstein, L. A.; Lougheed, R. W.; Moody, K. J.; Prussin, S. G.; Griffin, H. C.; Donangelo, R.

1998-05-01

261

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

262

Generation Next  

ERIC Educational Resources Information Center

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

Hawkins, B. Denise

2010-01-01

263

Generational Myth  

ERIC Educational Resources Information Center

College students in America are not as "digital" as one might wish to pretend. And even at elite universities, many are not rich enough. All the mystical talk about a generational shift and all the claims that kids won't read books are not true. In this article, the author challenges the notion of "digital natives." The author argues that the term…

Vaidhyanathan, Siva

2008-01-01

264

Generative Grammar  

ERIC Educational Resources Information Center

Discusses and illustrates three rule sets suitable for presenting generative grammar to beginners; and appendix to the author's article with the same title in the February 1970 (No. 13) issue, pp. 39-53; see TE 200 767. (Editor/SW)

Harwood, F. W.

1970-01-01

265

Generation and characterization of nanobodies targeting PSMA for molecular imaging of prostate cancer.  

PubMed

Nanobodies show attractive characteristics for tumor targeting in cancer diagnosis and therapy. A radiolabeled nanobody binding the prostate-specific membrane antigen (PSMA) could offer a noninvasive strategy to select prostate cancer patients eligible for PSMA-targeted therapies. We here describe the generation, production and in vivo evaluation of anti-PSMA nanobodies. Nanobodies were derived from heavy-chain-only antibodies, raised in immunized dromedaries. Binding characteristics were evaluated through ELISA and flow cytometry. Selected nanobodies were radiolabeled with (99m) Tc at their hexahistidine tail, after which cell binding capacity and internalization were evaluated on PSMA(pos) LNCaP and PSMA(neg) PC3 cell lines. In vivo tumor targeting was analyzed in both LNCaP and PC3 xenografted mice through SPECT/microCT and tissue sampling. A panel of 72 generated clones scored positive on ELISA, all contributing to three nanobody groups, of which group 3 dominated with 70 clones. ELISA and FACS analysis led to the selection of two dominant nanobodies. (99m) Tc-labeled PSMA6 and PSMA30 both showed specific binding on LNCAP cells, but not on PC3 cells. (99m) Tc-PSMA30 internalized significantly more in LNCaP cells compared to (99m) Tc-PSMA6. Higher absolute tumor uptake and tumor-to-normal organ ratios were observed for (99m) Tc-PSMA30 compared with (99m) Tc-PSMA6 and a (99m) Tc-control nanobody in LNCaP but not in PC3 tumor-bearing mice. PSMA30 nanobody has improved targeting characteristics both in vitro as well as in vivo compared with PSMA6 and the control nanobody, and was therefore selected as our in-house-developed lead compound for PSMA targeting. PMID:24700748

Evazalipour, Mehdi; D'Huyvetter, Matthias; Tehrani, Bahram Soltani; Abolhassani, Mohsen; Omidfar, Kobra; Abdoli, Shahriyar; Arezumand, Roghaye; Morovvati, Hamid; Lahoutte, Tony; Muyldermans, Serge; Devoogdt, Nick

2014-01-01

266

Ibogaine labeling with 99mTc-tricarbonyl: synthesis and transport at the mouse blood-brain barrier.  

PubMed

The (99m)Tc-tricarbonyl core may be used as an ideal tool for gamma-labeling ligands in noninvasive SPECT imaging. However, most (99m)Tc-tricarbonyl-labeled agents have difficulty crossing the blood-brain barrier (BBB). We radiolabeled the neuroactive indole ibogaine with (99m)Tc-tricarbonyl and measured its transport into the mouse brain by in situ brain perfusion. We measured the interactions of [(99m)Tc(CO)(3)-ibogaine](+) and (99m)Tc-tricarbonyl with the main BBB efflux transporters P-gp and BCRP in vitro and in vivo. Ibogaine was radiolabeled (yield: over 95%). [(99m)Tc(CO)(3)-ibogaine](+) entered the brain (K(in)) poorly (0.18 microL/g/s), at about the same rate as (99m)Tc-tricarbonyl (0.16 microL/g/s) and [(99m)Tc-sestamibi](+) (0.10 microL/g/s). The CNS tracer [(99m)Tc-HMPAO](0) entered the brain approximately 70-times higher than [(99m)Tc(CO)(3)-ibogaine](+). In vitro studies revealed that neither [(99m)Tc(CO)(3)-ibogaine](+) nor (99m)Tc-tricarbonyl ion were substrates for P-gp or BCRP. But lowering the membrane dipole potential barrier with phloretin enhanced the brain transport of [(99m)Tc(OH(2))(3)(CO)(3)](+) approximately 3-fold. Thus, ibogaine directly labeled with (99m)Tc-tricarbonyl is not suitable for CNS imaging because of its poor uptake. Brain transport is not restricted by efflux transporters but is reduced by its lipophilicity and interaction with the membrane-positive dipole potential. PMID:19492342

Tournier, Nicolas; André, Pascal; Blondeel, Sandy; Rizzo-Padoin, Nathalie; du Moulinet d'Hardemarre, Amaury; Declèves, Xavier; Scherrmann, Jean-Michel; Cisternino, Salvatore

2009-12-01

267

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

PubMed

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

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

2013-06-01

268

Preparation and evaluation of (99m)Tc-DMSA lyophilized kit for renal imaging.  

PubMed

Dimercaptosuccinic acid (DMSA) has been evaluated and used with technetium 99m ((99m)Tc) in imaging of kidneys. DMSA lyophilized kits were prepared and radiolabelled with (99m)Tc. Paper and thin-layer chromatography have been employed using various eluent systems for the radiochemical analysis, percentage labeling and binding capacity of (99m)Tc-DMSA. Female albino rabbits were used for this study. Biological data obtained after intravenous injection of radiolabelled DMSA to female albino rabbits revealed 32.42% uptake and long retention time in the kidneys. On the basis of animal biodistribution data, it is suggested that DMSA when labeled with (99m)Tc is useful complex for renal imaging and can be successfully applied as a diagnostic tool in nuclear medicine. Clinical biodistribution and radiation dosimetry studies are planned in future. PMID:23625428

Jan, Syed Umer; Abbass, Hafiz Ghulam

2013-05-01

269

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

SciTech Connect

99Technetium (99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life (t1/2 = 2.13 x 105 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron [Fe(II)], either in aqueous form or in mineral form, has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) have not been investigated. In this study the reactivity of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total Fe content of these clay minerals, after Fe-oxide removal, ranged from 0.7 to 30.4% by weight, and the Fe(III)/Fe(total) ratio ranged from 44.9 to 98.5%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella Putrifaciens CN32 cells as mediators. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. The extent of Fe(III) bioreduction was the highest for chlorite (~43 wt%) and the lowest for palygorskite (~4.17 wt%). In the S-I series, NAu-2 was the most reducible (~31 %) and illite the least (~0.4 %). The extent and initial rate of bioreduction were positively correlated with the percent smectite in the S-I series (i.e., layer expandability). Fe(II) in the bioreduced clay minerals subsequently was used to reduce Tc(VII) to Tc(IV) in PIPES buffer. Similar to the trend of bioreduction, in the S-I series, reduced smectite showed the highest reactivity toward Tc(VII), and reduced illite exhibited the least. The initial rate of Tc(VII) reduction, after normalization to clay and Fe(II) concentrations, was positively correlated with the percent smectite in the S-I series. Fe(II) in chlorite and palygorskite was also reactive toward Tc(VII) reduction. These data demonstrate that crystal chemical parameters (layer expandability, Fe and Fe(II) contents, and surface area etc.) play important roles in controlling the extent and rate of bioreduction and the reactivity toward Tc(VII) reduction. Reduced Tc(IV) resides within clay mineral matrix, and this association could minimize any potential of reoxidation over long term.

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

2011-07-01

270

Identification of the non-pertechnetate species in Hanford waste tanks, Tc(I) carbonyl complexes  

SciTech Connect

Immobilization of the high-level nuclear waste stored at the Hanford Reservation has been complicated by the presence of soluble, lower-valent technetium species. Previous work by Schroeder and Blanchard has shown that these species cannot be removed by ion-exchange and are difficult to oxidize. The Tc-K edge XANES spectra of the species in Tanks SY-101 and SY-103 were reported by Blanchard, but they could not be assigned to any known technetium complex. We report that the XANES spectra are most likely those of Tc(I) carbonyl species, especially fac-Tc(CO){sub 3}(gluconate){sup 2-}. This is further supported by EXAFS and {sup 99}Tc-NMR studies in nonradioactive simulants of these tank wastes.

Lukens, Wayne W.; Shuh, David K.; Schroeder, Norman C.; Ashley, Kenneth R.

2003-10-16

271

Production and survival of /sup 99/Tc in He-shell recurrent thermal pulses  

SciTech Connect

After a brief introduction to the present state of art of nuclear beta-decay studies in astrophysics, we report our recent work on the long-standing /sup 99/Tc problem. Having combined a detailed study of the recurrent He-shell thermal-pulse, third dredge-up episodes in a 2.25 M/sub solar/ star and an s-process network calculation, we show that a substantial amount of /sup 99/Tc can be produced by the s-process and can survive to be dredged up to the stellar surface. We stress that the factual observation of /sup 99/Tc at the surface of certain stars does not necessarily preclude the /sup 22/Ne(..cap alpha..,n)/sup 25/Mg reaction from remaining as the neutron source for the s-process. The calculated surface abundances of /sup 99/Tc and elements with neighboring atomic numbers are compared with observations. 43 refs., 5 figs.

Takahashi, K.; Mathews, G.J.; Ward, R.A.; Becker, S.A.

1985-05-30

272

An ultrafiltration technique for labeling red blood cells with Tc-99m.  

PubMed

This method automates the preparation of autologous Tc-99m labeled red blood cells utilizing the Amicon on-line column eluate concentrator to separate the plasma from the red blood cells. The red blood cells were pre-tinned with stannous diphosphonate and continuously recirculated over a 0.6 mu filter until all of the plasma was removed and the red blood cells remained suspended in a solution of 0.9% sodium chloride. Once the plasma has been removed the red blood cells are incubated with Tc-99m pertechnetate. The above Tc-99m red blood cells were compared to Tc-99m red blood cells produced in a similar manner except that centrifugation was used to separate the red blood cells from the plasma. Both preparations had a tagging efficiency of 98% or greater and rat distribution studies demonstrate that both preparations are equally stable as an in vivo intravascular agent. PMID:499240

Hendershott, L R; Gatson, R C; Ordway, F S; Ahmad, M

1979-06-01

273

Quality Control Validation for Exogenous Natural Surfactant Labeled with 99mTc  

Microsoft Academic Search

Objective: Exogenous natural surfactant (ENS) labeled with 99mTc shows an elevated lung specificity allowing the acqui- sition of high-quality images for ventilation scintigraphy. Methods: The methods for 99mTc-ENS quality control (phys- ical properties, pH determination, radiochemical studies, and biologic studies) were evaluated and validated. Results: The physical properties of the nonradioactive pre- cursor and of the radiopharmaceutical were analyzed as

Gabriela P. Calmanovici; Maria J. Salgueiro; Natalia M. Leonardi; Cinthia G. Goldman Bioch; Jorge O. Nicolini; Jose R. Boccio; Ricardo A. Caro

274

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

275

Tc 1Like Transposable Elements in the Genome of Lake Trout ( Salvelinus namaycush )  

Microsoft Academic Search

.   This study reports on the DNA sequence of a Tc1-like transposable element Tsn1 from lake trout (Salvelinus namaycush). Tc1-like elements were amplified by PCR using an oligonucleotide primer based on the Tdr1 element of zebrafish. One full-length and two partial-length copies of the transposon were sequenced. In addition, partial\\u000a Tsn1 elements were recovered from PCR reactions run with primers

Kent M. Reed

1999-01-01

276

Far-infrared Fabry-Perot filters and laser resonators with high-Tc superconductor reflectors  

Microsoft Academic Search

We report on far-infrared Fabry-Perot filters and laser resonators with high-Tc superconductor reflectors. We show that a MgO plate covered with a YBa2Cu3O7-delta thin film at low temperature (T<<Tc) can be used as a partially transparent mirror of high reflectivity up to the superconducting gap frequency of about 13 Thz. We demonstrate the use of reflectors for far-infrared narrow band

J. Schützmann; P. Wiese; X. Riederer; B. Gorshunov; A. Bespalov; J. Betz; K. F. Renk

1991-01-01

277

Regional brain uptake and retention of Tc-99m-propylene amine oxime derivatives  

SciTech Connect

Tc-99m-propylene amine oxime (Tc-99m-PnAO) is a neutral lipophilic chelate that rapidly and passively enters the cerebral cortex (80% on first pass in baboon brain) and then clears exponentially leaving inadequate activity to perform conventional SPECT brain imaging. When side chains are attached to the PnAO backbone lipophilicity is increased, as well as brain retention. In this work the authors evaluated regional brain uptake and retention of Tc-99m-PnAO and several of its derivatives in rat brain using serial autoradiography (ARG). Autoradiographs of each Tc-99m chelate at 5 sec. post peak brain uptake demonstrate discrete grey to white matter differentiation. White matter tracts are well delineated and the darker areas of grey matter appearing in the midbrain and thalamus, corresponding to areas of high capillary density and high blood flow documented with C-14-iodoantipyrine, are easily distinguished. Within 5 min. of the peak uptake the regional uptake and grey/white differentiation is lost on the Tc-99m-PnAO ARG. In contrast the 5 min. ARG of the more lipophilic Tc-99m, chelate with dimethyl-PnAO (DMPnAO) shows the complete reverse of the 5 sec. ARG, with greater activity in the white matter tracts than in the grey matter. One of the derivatives, tetramethyl-PAO (TMPAO) complexed with Tc-99m is retained in the grey matter of rat brain and shows persistent grey to white localization for at least 60 min., analogous to what has been reported with I-123-IMP. These results suggest that Tc-99m-TMPAO or one of its derivatives may be appropriate for SPECT imaging of cerebral blood flow abnormalities.

Chaplin, S.B.; Oberle, P.O.; Hoffman, T.J.; Volkert, W.A.; Holmes, R.A.; Nowotnik, D.P.; Pickett, R.D.; Neirinckx, R.

1985-05-01

278

Astrocytes as a Predominant Cellular Site of 99mTc-HMPAO Retention  

Microsoft Academic Search

Technetium-99m-d,l-hexamethylpropylene amine oxime (99mTc-HMPAO) retention in the brain monitored by single photon emission computed tomography (SPECT) is currently used as a marker of cerebral blood flow. The purported mechanism by which 99mTc-HMPAO accumulates in the brain is through its intracellular conversion from a lipophilic form to more hydrophilic derivatives within the brain parenchyma. The issue of the contribution of different

Sabrina Zerarka; Luc Pellerin; Daniel Slosman; Pierre J. Magistretti

2001-01-01

279

Cholecystitis: prospective evaluation of sonography and /sup 99m/ Tc-HIDA cholescintigraphy  

SciTech Connect

Major and minor criteria are determined for sonographic diagnosis of acute and chronic cholecystitis. A prospective study of 113 cases was performed on patients with suspected acute cholecystitis who were evaluated by cholesonography and /sup 99m/Tc-HIDA cholescintigraphy. Data support the use of sonography as the intial imaging procedure for the patient with suspected acute cholecystitis. /sup 99m/Tc-HIDA is useful in those cases without stones which exhibit minor criteria for gallbladder abnormality.

Worthen, N.J.; Uszler, J.M.; Funamura, J.L.

1981-11-01

280

Measurement of glomerular filtration rate in ICU patients using 99mTc-DTPA and inulin  

Microsoft Academic Search

Measurements of glomerular filtration rate in ICU patients using 99mTc-DTPA and inulin. Improved and reliable methods for assessing glomerular filtration rate (GFR) in intensive care patients are needed in light of known deficiencies using creatinine clearance. We compared simultaneous two-hour clearances of inulin (CIn), creatinine (CCr), and 99mTc-diethylenetriaminepentaacetic acid (CDTPA) in 18 medical or surgical intensive care patients (range, 49

William W Wharton; Jill L Sondeen; Michael McBiles; Stephen E Gradwohl; Charles E Wade; David P Ciceri; Heinz G Lehmann; Richard E Stotler; Thomas R Henderson; W Roscoe Whitaker; Jill S Lindberg

1992-01-01

281

ISO/TC 211/WG 9/N 014 Number of Pages:17  

E-print Network

://www-imai.is.s.u-tokyo.ac.jp/wg9/ #12;© ISO 2004 ­ All rights reserved Document type: International Standard Document subtype Version 2.1c2 ISO TC 211/SC N Date: 2004-08-16 ISO/WD 6709 ISO TC 211/SC /WG 9 Secretariat: NSF Standard complémentaire Warning This document is not an ISO International Standard. It is distributed for review

Imai, Hiroshi

282

ISO/TC 211/WG 9/N 013 Number of Pages:20  

E-print Network

://www-imai.is.s.u-tokyo.ac.jp/wg9/ #12;© ISO 2004 ­ All rights reserved Document type: International Standard Document subtype 2.1c2 ISO TC 211/SC N Date: 2004-08-07 ISO/WD 6709 ISO TC 211/SC /WG 9 Secretariat: NSF Standard complémentaire Warning This document is not an ISO International Standard. It is distributed for review

Imai, Hiroshi

283

Leaching Tc-99 from SRP glass in simulated tuff and salt groundwaters  

SciTech Connect

Results of leach tests with Tc-99 doped SRP borosilicate waste glass are presented. The glass was prepared by melting a mixture of SRP 165 powdered frit doped with a carrier free solution of Tc-99 at 1150{sup 0}C. Dissolution of portions of the resulting glass indicated that the Tc-99 was distributed homogeneously throughout the glass. Static leach tests up to 90 days were performed at 90{sup 0}C in J-13 tuff groundwater or WIPP brine A at a SA/V of 100m{sup -1}. Normalized mass losses were calculated for Tc-99 as well as all the major elements in the glass. Results indicated that under ambient oxidizing conditions Tc-99 leached no faster than the glass-forming elements of the glass. In J-13 water, Tc-99 leached congruently with B. In WIPP brine A, it leached congruently with Si. Leach rates for Li were higher in both groundwaters, probably due to a contribution from an ion exchange mechanism. Leach tests were performed under reducing conditions in J-13 water by adding Zn/Hg amalgam to the leachate. In these tests the pH increased significantly, probably because of the reaction of the amalgam with the water. In a 21-day test, the pH increased to 13 and leach rates for the glass were very high. Even though there was signifcant dissolution of the glass, the normalized mass loss based on Tc-99 was only 0.02g/m{sup 2}. This result and the fact that reducing conditions at normal pH values do not significantly affect the dissolution of the glass, indicate that the low concentrations for Tc-99 obtained under reducing conditions are due to is solubility and not due to an increased durability of the glass. 14 refs., 2 figs., 5 tabs.

Bibler, N.E.; Jurgensen, A.R.

1987-01-01

284

Developing synergistic and complementary effects in textiles and clothing (T&C) supply for Greater China  

Microsoft Academic Search

The textiles and clothing (T&C) industries in the Greater China region (China, Hong Kong, Macau and Taiwan) began to integrate with each other based on their advantageous factor endowments in line with the structural transition of economic developments since the 1980s. This rationalization has not only resulted in the T&C industry of the territory being able to secure competitive advantage

K. F. Au; H. W. Yu

2002-01-01

285

Water-stable fac-{TcO?}? complexes - a new field of technetium chemistry.  

PubMed

The development of technetium chemistry has been lagging behind that of its heavier congener rhenium, primarily because the inherent radioactivity of all Tc isotopes has limited the number of laboratories that can study the chemistry of this fascinating element. Although technetium is an artificial element, it is not rare. Significant amounts of the isotope (99)Tc are produced every day as a fission byproduct in nuclear power plants. Therefore, a fundamental understanding of the chemistry of (99)Tc is essential to avoid its release into the environment. In this article the chemistry of technetium at its highest oxidation state (+VII) is reviewed with a special focus on recent developments which make water-stable complexes of the general type [TcO(3)(tacn-R)](+) (tacn-R = 1,4,7-triazacyclononane or derivatives) accessible. Complexes containing the fac-{TcO(3)}(+) core display a unique reactivity. In analogy to [OsO(4)] and [RuO(4)], complexes containing the fac-{TcO(3)}(+) core undergo with alkenes metal-mediated, vicinal cis-dihydroxylation reactions (alkene-glycol interconversion) in water via a (3+2)-cycloaddition reaction. Therefore, water-stable fac-{(99m)TcO(3)}(+) complexes pave the way for a new labeling strategy for radiopharmaceutical applications, based on (3+2)-cycloaddition reactions. This new concept for the labeling of biomolecules with small [(99m)TcO(3)(tacn-R)](+)-type complexes by way of a (3+2)-cycloaddition with alkenes is discussed in detail. The herein reported developments in high-valent technetium chemistry create a new field of research with this artificial element. This demonstrates the potential of fundamental research to provide new impetus of innovation for the development of new methods for radiopharmaceutical applications. PMID:22054130

Braband, Henrik

2011-01-01

286

Spectroscopic evidence for a pseudogap in the normal state of underdoped high-Tc superconductors  

Microsoft Academic Search

IT is well known that BCS mean-field theory is remarkably successful in describing conventional superconductors. A central concept of BCS theory is the energy gap in the electronic excitation spectrum below the superconducting transition temperature, Tc. The gap also serves as the order parameter: quite generally, long-range phase coherence and a non-zero gap go hand-in-hand1. But in underdoped high-Tc superconductors

H. Ding; T. Yokoya; J. C. Campuzano; T. Takahashi; M. Randeria; M. R. Norman; T. Mochiku; K. Kadowaki; J. Giapintzakis

1996-01-01

287

Computed tomography and bone scintigraphy is polyostotic fibrous dysplasia. Report of a case. [Tc 99m  

SciTech Connect

A case of polyostotic fibrous dysplasia is presented in which the extent of bony lesions was defined on the results of the CT scan and bone scan with 99m Tc polyphosphate in addition to conventional radiography. These diagnostic procedures appear to be of considerable value in defining the extent of a variety of oral-maxillofacial bony lesions. This report describes the comparative findings from 99m Tc polyphosphate bone imaging and computed tomography (CT) in one patient with polyostotic fibrous dysplasia.

Higashi, T.; Iguchi, M.; Shimura, A.; Kruglik, G.D.

1980-12-01

288

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

SciTech Connect

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

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

1994-05-01

289

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

290

TC10 controls human myofibril organization and is activated by the sarcomeric RhoGEF obscurin.  

PubMed

The contractile activity of striated muscle depends on myofibrils that are highly ordered macromolecular complexes. The protein components of myofibrils are well characterized, but it remains largely unclear how signaling at the molecular level within the sarcomere and the control of assembly are coordinated. We show that the Rho GTPase TC10 appears during differentiation of human primary skeletal myoblasts and it is active in differentiated myotubes. We identify obscurin, a sarcomere-associated protein, as a specific activator of TC10. Indeed, TC10 binds directly to obscurin via its predicted RhoGEF motif. Importantly, we demonstrate that obscurin is a specific activator of TC10 but not the Rho GTPases Rac and Cdc42. Finally, we show that inhibition of TC10 activity by expression of a dominant-negative mutant or its knockdown by expression of specific shRNA block myofibril assembly. Our findings reveal a novel signaling pathway in human skeletal muscle that involves obscurin and the Rho GTPase TC10 and implicate this pathway in new sarcomere formation. PMID:19258391

Coisy-Quivy, Marjorie; Touzet, Olivia; Bourret, Annick; Hipskind, Robert A; Mercier, Jacques; Fort, Philippe; Philips, Alexandre

2009-04-01

291

Hg,Re-1223 system: Tc dependence on hydrostatic pressure and thermopower measurements  

NASA Astrophysics Data System (ADS)

Samples of Hg 1- xRe xBa 2Ca 2Cu 3O 8+ ? superconductor (Hg,Re-1223) were prepared with varying rhenium (Re) nominal content (0.15? x?0.20) in order to study the changes on the critical temperature under external hydrostatic pressure. At low pressures the ? Tc/? P depends strongly on the Re doping and the sample with x=0.18 shows the largest measured value. However, thermopower measurements reveal that there is no significant change in the numbers of carriers for the different Re content (0.15? x?0.20) meaning that ? Tc/? n is the same for all samples which, in principle, have an optimal oxygen content. Taking into account that d Tc/d P=? Tci/? P+[? Tc/? n][? n/? P] and ? Tc/? n does not depend on the Re content we can argue that the intrinsic term (? Tci/? P) determines the influence of external hydrostatic pressure on Tc.

Orlando, M. T. D.; de Mello, E. V. L.; Passos, C. A. C.; Caputo, M. R. C.; Martinez, L. G.; Zeini, B.; Yugue, E. S.; Vanoni, W.; Baggio-Saitovitch, E.

2001-11-01

292

Controlling factors of Tc dome structure in 1111-type iron arsenide superconductors  

NASA Astrophysics Data System (ADS)

We investigated the effects of phosphorus substitution on the shape of the Tc(x) dome in 1111-type SmFeAs1-yPyO1-xHx (0 < x < 0.5). Hydride ion substitution of oxide sites (O2- ? H-) exerts a chemical pressure effect, i.e., a structural reduction of the Pn-Fe-Pn angle ? (Pn = P, As) and also dopes electrons into the FePn layer to induce superconductivity. Isovalent phosphorus substitution (P3- ? As3-) can induce only a chemical pressure effect, i.e., an increase of ? for La substitution of Sm sites. As y increases from 0.0 to 0.5, the single Tc dome gradually splits into two domes, similar to those of LaFeAsO1-xHx with a Tc valley at x ? 0.16. We found that the Tc valley is located around (x, ?) ? (0.16, 113°) for both of the SmFeAs1-yPyO1-xHx and LaFeAsO1-xHx series, irrespective of changes in the Pn anion and Ln cation species. This result suggests that suppression of Tc leads to the emergence of a Tc valley when both the shape of FePn4 tetrahedra represented by ? and electron-doping level of x meet the above criterion in 1111-type iron oxypnictide superconductors.

Matsuishi, Satoru; Maruyama, Takuya; Iimura, Soshi; Hosono, Hideo

2014-03-01

293

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

SciTech Connect

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

Kato-Azuma, M.

1982-06-01

294

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

295

Scintigraphic evaluation of Tc-99m-low-density lipoprotein (LDL) distribution in patients with Gaucher disease.  

PubMed

Gaucher disease (GD) is frequently associated with reduced plasma levels of low density lipoproteins, presumably due to increased catabolism of LDL. The purpose of this study was to determine the distribution of Tc-99m LDL (Tc-LDL) in Gaucher patients, and compare the findings to bone marrow distribution. Four patients with non-neuropathic Gaucher disease (type 1) underwent baseline whole body imaging at 4 and 24 h after injection of dialyzed autologous LDL labeled with 10-20 mCi Tc-99m-pertechnetate. Three of the four patients were treated with macrophage-targeted alglucerase (Ceredase). The LDL studies were compared to concurrent bone marrow scans performed with 10 mCi Tc-99m sulfur colloid (Tc-SC). Follow-up Tc-LDL and Tc-SC scans were obtained 12-14 months later. Tc-LDL activity was abnormally increased in the spleen and long bones of the upper and lower extremities. Liver activity was also increased. Prominent blood pool activity 4 h after injection mostly cleared on the 24-hour images. The distribution of Tc-SC was congruent with Tc-LDL activity. All patients had mild-to-moderate hepatomegaly and peripheral bone marrow expansion. One patient had been previously splenectomized and the remaining three had moderate-to-severe splenomegaly. Two of the three treated patients showed regression of peripheral bone marrow activity with therapy, along with a comparable decrease in Tc-LDL uptake. Our study with Tc-LDL and Tc-SC suggests that in patients with Gaucher disease native LDL is taken up by the reticuloendothelial system (RES) of the spleen and bone marrow in addition to increased uptake by the liver. This abnormal uptake (presumably by macrophages of the RES) may account for accelerated LDL catabolism and reduced plasma levels of LDL. Serial LDL studies can be performed, allowing for longitudinal follow-up after drug or enzyme therapies. PMID:9272706

Lorberboym, M; Vallabhajosula, S; Lipszyc, H; Pastores, G

1997-07-01

296

Activity measurements of the radionuclide 99mTc for the IFIN-HH, Romania in the ongoing comparison BIPM.RI(II)-K4.Tc-99m  

NASA Astrophysics Data System (ADS)

In 2013, a comparison of activity measurements of 99mTc using the Transfer Instrument of the International Reference System (SIRTI) took place at the Institutul National de Cercetare - Dezvoltare in Fizica si Inginerie Nucleara - 'Horia Hulubei' (IFIN-HH, Romania). Ampoules containing about 21 kBq and 40 kBq of a 99mTc solution were measured in the SIRTI for, respectively, one and three half-lives. The comparison, identifier BIPM.RI(II)-K4.Tc-99m, is linked to the BIPM.RI(II)-K1.Tc-99m comparison and the degrees of equivalence with the key comparison reference value and between the present IFIN-HH result, the other K4 participants and the six participants in the K1 comparison have been evaluated. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Michotte, C.; Sahagia, M.; Ioan, M. R.; Antohe, A.; Luca, A.

2014-01-01

297

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

298

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

PubMed Central

Objective: For immunotherapy of human papillomavirus (HPV) -16-associated cervical cancers the E7 protein is considered a prime candidate. However it is a poor inducer of cytotoxic T-cell response, when being used as a singular antigen in protein vaccination. Hence, in this study we focused on the utilization of a vaccine delivery system for prevention or treatment of cervical cancer. Materials and Methods: In this experimental study, we designed and evaluated a novel fusion protein comprising HPV16 E7 antigen fused to Shiga toxin B-subunit (STxB) as both an antigen vector and an adjuvant. Then we designed two preventive and therapeutic tumor models to investigate the prevention and inhibition of TC-1 cell growth in female C57BL/6 mice, respectively. In each model, mice were immunized with the recombinant protein of E7-STxB or E7 without any adjuvant. Results: We demonstrated that prophylactic immunization of E7-STxB protected mice against TC-1 cells. Also in the therapeutic model, E7-STxB inhibited TC-1 tumor growth inlungs. The results were significant when compared with the immunization of E7 singularly. Conclusion: We concluded that immunization with the E7-STxB protein without any adjuvant could generate anti-tumor effect in mice challenged with TC-1 cells.This research verifies the clinical applications and the future prospects of developing HPV16 E7 therapeutic vaccines fused to immunoadjuvants. PMID:23862120

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

2013-01-01

299

Potential and limitations of Tc-99m sestamibi scintigraphy for the diagnosis of myocardial viability.  

PubMed

Sestamibi is a Tc labeled radiotracer particularly suitable for myocardial perfusion studies, providing similar information as thallium scintigraphy for the diagnosis of coronary artery disease. In comparison with thallium, sestamibi has the advantage of improved imaging properties due to its higher gamma emission. This is particularly relevant when SPECT imaging is considered. The myocardial uptake of sestamibi is partially passively, related to the myocardial flow, and is also related to the metabolic cellular activity, as it is proportional to the electrochemical gradient generated at cell membrane level. While the role for sestamibi in diagnosing coronary artery disease is well accepted, it is still controversial for the assessment of myocardial viability. Clinical studies reported by others and results from our own institution will be described both in the setting of a recent myocardial infarction (myocardial stunning) and of longstanding left ventricular dysfunction (hibernating myocardium). The results concordantly suggest that sestamibi underestimates myocardial viability, compared to the accepted standards of thallium (rest-redistribution or stress-reinjection protocols), 18-F FDG PET and also in the prediction of left ventricular functional recovery after revascularisation. However, the data available at present are very limited, particularly after revascularisation. Furthermore, according to new promising results, the role of sestamibi in the setting of myocardial viability has potential for improvement, if the injection at rest will be performed during nitrates. It is also foreseen that the combined use of sestamibi perfusion/wall motion scan (first pass and/or gated perfusion studies) and the development of new softwares for attenuation correction might improve the results in the setting of myocardial viability. PMID:8150411

Cornel, J H; Arnese, M; Forster, T; Postma-Tjoa, J; Reijs, A E; Fioretti, P M

1994-02-01

300

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

301

Assessment of the role in protection and pathogenesis of the Chlamydia muridarum V-type ATP synthase subunit A (AtpA) (TC0582).  

PubMed

A novel Chlamydia muridarum antigen (TC0582) was used to vaccinate BALB/c mice. Mice were also immunized with other components of the ATP synthase complex (TC0580, TC0581, and TC0584), or with the major outer membrane protein (MOMP). TC0582 was also formulated in combination with TC0580, TC0581 or MOMP. TC0582 alone, or in combination with the other antigens, elicited strong Chlamydia-specific humoral and cellular immune responses. Vaccinated animals were challenged intranasally and the course of the infection was followed for 10 days. Based on percentage change in body weight, lung weight, and number of Chlamydia inclusion forming units recovered from the lungs, mice immunized with TC0582, TC0581 or MOMP, as single antigens, showed significant protection. Mice immunized with combinations of two antigens were also protected but the level of protection was not additive. TC0582 has sequence homology with the eukaryotic ATP synthase subunit A (AtpA). Therefore, to determine if immunization with TC0582, or with Chlamydia, elicited antibodies that cross-reacted with the mouse AtpA, the two proteins were printed on a microarray. Sera from mice immunized with TC0582 and/or live Chlamydia, strongly reacted with TC0582 but did not recognize the mouse AtpA. In conclusion, TC0582 may be considered as a Chlamydia vaccine candidate. PMID:24161793

Cheng, Chunmei; Jain, Pooja; Pal, Sukumar; Tifrea, Delia; Sun, Guifeng; Teng, Andy A; Liang, Xiaowu; Felgner, Philip L; de la Maza, Luis M

2014-02-01

302

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

PubMed Central

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

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

2013-01-01

303

Expression of an endoglucanase from Tribolium castaneum (TcEG1) in Saccharomyces cerevisiae.  

PubMed

Insects are a largely unexploited resource in prospecting for novel cellulolytic enzymes to improve the production of ethanol fuel from lignocellulosic biomass. The cost of lignocellulosic ethanol production is expected to decrease by the combination of cellulose degradation (saccharification) and fermentation of the resulting glucose to ethanol in a single process, catalyzed by the yeast Saccharomyces cerevisiae transformed to express efficient cellulases. While S. cerevisiae is an established heterologous expression system, there are no available data on the functional expression of insect cellulolytic enzymes for this species. To address this knowledge gap, S. cerevisiae was transformed to express the full-length cDNA encoding an endoglucanase from the red flour beetle, Tribolium castaneum (TcEG1), and evaluated the activity of the transgenic product (rTcEG1). Expression of the TcEG1 cDNA in S. cerevisiae was under control of the strong glyceraldehyde-3 phosphate dehydrogenase promoter. Cultured transformed yeast secreted rTcEG1 protein as a functional ?-1,4-endoglucanase, which allowed transformants to survive on selective media containing cellulose as the only available carbon source. Evaluation of substrate specificity for secreted rTcEG1 demonstrated endoglucanase activity, although some activity was also detected against complex cellulose substrates. Potentially relevant to uses in biofuel production rTcEG1 activity increased with pH conditions, with the highest activity detected at pH 12. Our results demonstrate the potential for functional production of an insect cellulase in S. cerevisiae and confirm the stability of rTcEG1 activity in strong alkaline environments. PMID:24318365

Shirley, Derek; Oppert, Cris; Reynolds, Todd B; Miracle, Bethany; Oppert, Brenda; Klingeman, William E; Jurat-Fuentes, Juan Luis

2014-10-01

304

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.

305

Deposition of high Tc Nb- (Ge,Si) films at substrate temperature below 400/sup 0/C by magnetron sputtering  

SciTech Connect

Deposition of Si substituted A15 Nb-(Ge, Si) films has been attempted by using a magnetron sputtering apparatus. The dependence of crystal structure and superconducting critical temperature Tc of these films on sputtering conditions and film composition has been investigated. The authors have succeeded in depositing the single phase A15 Nb/sub 3/(Ge,Si) films which show a small lattice constant about 5.11 A and high Tc of 23.1 K on fused silica substrate. The films with Tc above 20 K are obtained in the following region: Si substitution ration about 0.12, (Ge+Si) content from 23 to 27 at .% and substrate temperature is much wider and 200 K lower than that for high Tc Nb/sub 3/Ge binary compound. Besides, in these films, Tc does not depend on film thickness significantly and the films less than 1000 A thick have Tc above 20 K.

Terada, N.; Hoshi, Y.; Naoe, M.; Yamanaka, S.

1982-11-01

306

Improving the yield of preoperative parathyroid localization: Technetium Tc 99m-sestamibi imaging after thyroid suppression  

Microsoft Academic Search

Background. Preoperative localization is essential for successful directed, minimally invasive or reoperative parathyroidectomy. Standard technetium Tc 99m-sestamibi imaging is the most sensitive modality for localization. We reviewed our experience with 99mTc-sestamibi imaging and specifically investigated the effect of thyroid suppression on repeat imaging of patients who had initially nonlocalizing scans. Methods. The records of patients who underwent 99mTc-sestamibi imaging during

Richard E Royal; Ebrahim S Delpassand; Suzanne E Shapiro; Herbert A Fritsche; Rena Vassilopoulou-Sellin; Steven I Sherman; Robert F Gagel; Douglas B Evans; Jeffrey E Lee

2002-01-01

307

An evaluation of the mediastinal lymphoscintigram for carcinoma of the esophagus studied with 99m Tc rhenium sulfur colloid  

Microsoft Academic Search

Lymphoscintigraphies of esophageal carcinoma in nine patients were studied with the aid of 99mTc-labeled rhenium sulfur colloid (99mTc-Re). 99mTc-Re was injected into the submucosal layer of the esophagus (just above the oral side of the tumor) using an esophagoendoscope, 1 or 2 days before operation. Lymphoscintigraphies at intervals of 1, 3, and 20 h after the injection were performed. After

Shoji Terui; Hoichi Kato; Toshio Hirashima; Toshifumi Iizuka; Hiyoshimaru Oyamada

1982-01-01

308

99mTc-HMPAO as a tracer of cerebral blood flow in newborn infants.  

PubMed

Studies on the kinetics of 99mTc-D,L-hexamethylpropylene amine oxime (99mTc-HMPAO) in adults have shown that it is not an ideal tracer of CBF because it underestimates high-flow areas. Knowledge of the kinetics of the tracer is important in evaluating the studies. The kinetics of 99mTc-HMPAO in infants may be different from that in adults, therefore, we examined the cerebral uptake and retention of 99mTc-HMPAO in neonates and estimated the degree of brain-to-blood back diffusion by comparing corresponding 133Xe flow images and 99mTc-HMPAO distribution images. In addition, we measured the urinary excretion of 99mTc-HMPAO. Regional CBF was measured using a mobile brain-dedicated, fast-rotating, four-head multidetector system specially designed for neonatal studies. Tracers were 99mTc-HMPAO (4 MBq/kg) and 133Xe (500 MBq/kg). Cerebral uptake and leak-out of 99mTc-HMPAO were measured by a single scintillation crystal placed over the frontoparietal part of the infant's head. The cerebral retention of 99mTc-HMPAO was analyzed in 50 infants. The mean gestational age and birth weight (95% confidence interval) were 34.4 weeks (32.2-35.7) and 2,326 g (1,954-2,995), respectively. The cerebral uptake of 99mTc-HMPAO was examined in 16 of the 50 infants, and activity during 24 h was monitored in five. In 11 infants, corresponding 133Xe studies were performed. Urinary excretion was studied in 12 infants. The maximal activity in the brain was reached 90s after i.v. injection and was 104% (98-111) of the stable level, which was reached approximately 3 min after the injection. The decay corrected leakout of the tracer during the following 24 h was 1.0% (0.4-1.5) per hour. The cerebral retention was calculated at 6.8% (6.1-7.6), highest in the group of ictal studies and lowest in premature infants with intracranial hemorrhage. The mean value of the fixation/clearance ratio alpha was estimated at 3.4 (2.8-4.4). The mean urinary excretion over 24 h was 19.5% (11.4-27.7) and was significantly related to renal function as indicated by serum urea (p = 0.02 r2 = 0.55). A four-compartment model describing the kinetics of 99mTc-HMPAO is shown to be valid in neonates. The cerebral retention of the tracer is higher in neonates because of higher extraction and lower initial back diffusion from brain to blood. In linearizing 99mTc-HMPAO distribution images, a smaller correction is necessary, and we propose a value of the correction factor of 3.4. In this way, 99mTc-HMPAO is a more reliable tracer of the distribution of CBF in neonates compared with adults. The urinary excretion is significantly reduced compared with adults, and the radiation dose to the bladder wall is reduced. The effective dose is 0.3 mSv/MBq/kg. PMID:9143227

Børch, K; Greisen, G

1997-04-01

309

Serum-Mediated Activation of Macrophages Reflects TcVac2 Vaccine Efficacy against Chagas Disease  

PubMed Central

Chagas disease is endemic in Latin America and an emerging infectious disease in the United States. No effective treatments are available. The TcG1, TcG2, and TcG4 antigens are highly conserved in clinically relevant Trypanosoma cruzi isolates and are recognized by B and T cells in infected hosts. Delivery of these antigens as a DNA prime/protein boost vaccine (TcVac2) elicited lytic antibodies and type 1 CD8+ T cells that expanded upon challenge infection and provided >90% control of parasite burden and myocarditis in chagasic mice. Here we determined if peripheral blood can be utilized to capture the TcVac2-induced protection from Chagas disease. We evaluated the serum levels of T. cruzi kinetoplast DNA (TckDNA), T. cruzi 18S ribosomal DNA (Tc18SrDNA), and murine mitochondrial DNA (mtDNA) as indicators of parasite persistence and tissue damage and monitored the effect of sera on macrophage phenotype. Circulating TckDNA/Tc18SrDNA and mtDNA were decreased by >3- to 5-fold and 2-fold, respectively, in vaccinated infected mice compared to nonvaccinated infected mice. Macrophages incubated with sera from vaccinated infected mice exhibited M2 surface markers (CD16, CD32, CD200, and CD206), moderate proliferation, a low oxidative/nitrosative burst, and a regulatory/anti-inflammatory cytokine response (interleukin-4 [IL-4] plus IL-10 > tumor necrosis factor alpha [TNF-?]). In comparison, macrophages incubated with sera from nonvaccinated infected mice exhibited M1 surface markers, vigorous proliferation, a substantial oxidative/nitrosative burst, and a proinflammatory cytokine response (TNF-? ? IL-4 plus IL-10). Cardiac infiltration of macrophages and TNF-? and oxidant levels were significantly reduced in TcVac2-immunized chagasic mice. We conclude that circulating TcDNA and mtDNA levels and macrophage phenotype mediated by serum constituents reflect in vivo levels of parasite persistence, tissue damage, and inflammatory/anti-inflammatory state and have potential utility in evaluating disease severity and efficacy of vaccines and drug therapies. PMID:24421046

Gupta, Shivali; Silva, Trevor S.; Osizugbo, Jessica E.; Tucker, Laura; Spratt, Heidi M.

2014-01-01

310

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

SciTech Connect

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

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

1985-05-01

311

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

SciTech Connect

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

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

1989-04-01

312

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

313

Collybistin activation by GTP-TC10 enhances postsynaptic gephyrin clustering and hippocampal GABAergic neurotransmission  

PubMed Central

In many brain regions, gephyrin and GABAA receptor clustering at developing inhibitory synapses depends on the guanine nucleotide exchange factor collybistin (Cb). The vast majority of Cb splice variants contain an autoinhibitory src homology 3 domain, and several synaptic proteins are known to bind to this SH3 domain and to thereby activate gephyrin clustering. However, many functional GABAergic synapses form independently of the known Cb-activating proteins, indicating that additional Cb activators must exist. Here we show that the small Rho-like GTPase TC10 stimulates Cb-dependent gephyrin clustering by binding in its active, GTP-bound state to the pleckstrin homology domain of Cb. Overexpression of a constitutively active TC10 variant in neurons causes an increase in the density of synaptic gephyrin clusters and mean miniature inhibitory postsynaptic current amplitudes, whereas a dominant negative TC10 variant has opposite effects. The enhancement of Cb-induced gephyrin clustering by GTP-TC10 does not depend on the guanine nucleotide exchange activity of Cb but involves an interaction that resembles reported interactions of other small GTPases with their effectors. Our data indicate that GTP-TC10 activates the major src homology 3 domain-containing Cb variants by relieving autoinhibition and thus define an alternative GTPase-driven signaling pathway in the genesis of inhibitory synapses. PMID:24297911

Mayer, Simone; Kumar, Rohit; Jaiswal, Mamta; Soykan, Tolga; Ahmadian, Mohammad Reza; Brose, Nils; Betz, Heinrich; Rhee, Jeong-Seop; Papadopoulos, Theofilos

2013-01-01

314

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

315

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

PubMed

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

316

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

317

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

318

Micro-XAFS study of Tc and Mn in bioreduced Hanford sediments  

NASA Astrophysics Data System (ADS)

Micro-XAFS measurements of Tc and Mn in bioreduced Hanford sediments have been obtained using an x-ray microprobe at the PNC-CAT beamline at the Advanced Photon Source. Tc in the form of pertechnetate is highly mobile and is one of the most hazardous components of the waste that has leaked from Hanford storage tanks. Manganese reducing bacteria can strongly enhance the conversion of pertechnetate to much less mobile Tc(IV) forms. To study this process, pertechnetate exposed Hanford sediments from the Ringold formation were treated with bacteria for varying periods of time. The reduction of Mn to a Mn(II) rhodochrosite-like phase can clearly tracked by XANES. XANES also shows a reduction of the pertechnetate to a TcO2-like phase. This reduced Tc is found to be associated with Mn and Fe containing mineral grains. *The PNC-CAT is supported by the U. S. DOE and the Canadian NSERC. The APS is supported by DOE contract no. W-31-109-Eng-38. PNNL is operated by Battelle Memorial Institute for the DOE.

Heald, S. M.; McKinley, J. P.; Zachara, J. M.

2002-03-01

319

Transcranial cerebellar direct current stimulation (tcDCS): motor control, cognition, learning and emotions.  

PubMed

The neurological manifestations of cerebellar diseases range from motor to cognitive or behavioral abnormalities. Experimental data in healthy subjects extend the cerebellar role to learning, emotional and mood control. The need for a non-invasive tool to influence cerebellar function in normal and pathological conditions led researchers to develop transcranial cerebellar direct current stimulation (tcDCS). tcDCS, like tDCS, depends on the principle that weak direct currents delivered at around 2mA for minutes over the cerebellum through surface electrodes induce prolonged changes in cerebellar function. tcDCS modulates several cerebellar skills in humans including motor control, learning and emotional processing. tcDCS also influences the cerebello-brain interactions induced by transcranial magnetic stimulation (TMS), walking adaptation, working memory and emotional recognition. Hence tcDCS is a simple physiological tool that can improve our physiological understanding of the human cerebellum, and should prove useful also in patients with cerebellar dysfunction or psychiatric disorders and those undergoing neurorehabilitation to enhance neuroplasticity. PMID:23664951

Ferrucci, Roberta; Priori, Alberto

2014-01-15

320

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

321

Technologies for translational imaging using generators in oncology.  

PubMed

Improvement of scintigraphic tumor imaging is extensively determined by the development of more tumor specific radiopharmaceuticals. Thus, to improve the differential diagnosis, prognosis, planning and monitoring of cancer treatment, several functional pharmaceuticals have been developed. The application of molecular targets for cancer imaging, therapy and prevention using generator-produced isotopes is the major focus of many ongoing research projects. Radionuclide imaging modalities (single photon emission computed tomography, SPECT; positron emission tomography, PET) are diagnostic cross-sectional imaging techniques that map the location and concentration of radionuclide-labeled radiotracers. Generator produced isotopes, such as 99mTc and 68Ga, are readily available and affordable. 99mTc (t1/2=6 hr; 140 keV) is used for SPECT and 68Ga (t1/2=68 min; 511 keV, 89%) is used for PET. 99mTc- and 68Ga-labeled agents using various chelators have been synthesized and their potential uses to assess tumor targets have been evaluated. Molecular targets labeled with 99mTc and 68Ga can be utilized for the prediction of therapeutic response, monitoring tumor response to treatment and aiding in the differential diagnosis of tumor versus non-tumor tissue. Molecular targets for oncological research in (1) cell apoptosis, (2) gene and nucleic acid-based approach, (3) angiogenesis (4) tumor hypoxia, and (5) metabolic imaging are discussed. Numerous imaging ligands in these categories have been developed and evaluated in animals and humans. Molecular targets were imaged and their potential to redirect optimal cancer diagnosis and therapeutics was demonstrated. PMID:18221069

Schechter, Naomi R; Yang, David J; Azhdarinia, Ali; Chanda, Mithu

2007-11-01

322

Saving the "Lost Generation"  

ERIC Educational Resources Information Center

Since the beginning of the American experience, labels have been used to describe generations. Among them are the "Puritan generation," the "greatest generation," the "baby boomer generation" and the "MTV generation." Today, people are creating a new generation--the "lost generation." The lost generation represents a large and growing population…

Beebe, Anthony E.

2007-01-01

323

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

324

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

325

Quality control of Tc-99m DTPA for measurement of glomerular filtration: concise communication  

SciTech Connect

When technetium-99m DTPA is used to measure glomerular filtration rate (GFR), the accuracy depends on the supplier of the radiopharmaceutical. The error in GFR is due to protein binding, as we have shown by direct measurement. In 19 patients, GFR measured with Tc-DTPA and corrected for protein binding agreed with that measured simultaneously using Yb-169 DTPA (correlation coefficient 0.991). Without correction, Tc-DTPA gave falsely low values in patients having good renal function, in whom unbound activity cleared rapidly while bound activity remained in the circulation. When Tc-DTPA is used to measure GFR, the in vivo protein binding should be measured and used to correct the data.

Russell, C.D. (Univ. of Alabama, Birmingham); Bischoff, P.G.; Rowell, K.L.; Kontzen, F.; Lloyd, L.K.; Tauxe, W.N.; Dubovsky, E.V.

1983-08-01

326

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

327

Characterization of a Tc1-like transposon in the Antarctic ice-fish, Chionodraco hamatus.  

PubMed

We report the presence of Tc1 transposon-like sequences in the Antarctic ice-fish Chionodraco hamatus, belonging to the Notothenioidei. The complete DNA sequence of these transposon-like elements is reduced in length compared to other Tc1 transposons, but it appears to share significant structural similarities with them. It contains a degenerate open reading frame, whose inferred 264 amino acid sequence shares sequence similarity with the 'aspartic acid, aspartic acid (35) glutamic acid' family of transposases, particularly those from Caenorhabditis species (sp.) and Drosophila sp. Southern blot analysis and polymerase chain reaction amplification indicate that Tc1 transposon-like sequences are present in other notothenioid species, though their amount can vary in the different lineages. PMID:12354653

Capriglione, Teresa; Odierna, Gaetano; Caputo, Vincenzo; Canapa, Adriana; Olmo, Ettore

2002-08-01

328

/sup 99//sup m/Tc-labeled macroaggregated albumin in intrahepatic arterial chemotherapy  

SciTech Connect

One hundred eighty-four /sup 99//sup m/Tc-labeled macroaggregated albumin (/sup 99//sup m/Tc-MAA) perfusion studies were carried out in 39 patients with histologically proven primary (four) and metastatic (35) hepatic neoplasms. Three different patterns of tumor perfusion were observed: (1) increased central radioactivity (33%); (2) decreased central radioactivity (33%); and (3) mixed and/or diffuse radioactivity (33%). Extrahepatic perfusion as evidenced by radioactive localization in the region of the stomach, pancreas, and small bowel was noted in 51%. Its presence was associated with a higher incidence of gastrointestinal complications (45% vs. 16%). Tumor arteriovenous shunting was demonstrated in 38%, showing localization of radiotracer activity in the lungs, and decreased as tumors decreased in size. The use of /sup 99//sup m/Tc-MAA infusion studies in intrahepatic arterial chemotherapy offers an excellent evaluation of catheter placement and tumor perfusion, in addition to helping to avoid gastrointestinal complications.

Bledin, A.G.; Kantarjian, H.M.; Kim, E.E.; Wallace, S.; Chuang, V.P.; Patt, Y.Z.; Haynie, T.P.

1982-10-01

329

/sup 99m/Tc-labeled macroaggregated albumin in intrahepatic arterial chemotherapy  

SciTech Connect

One hundred eighty-four /sup 99m/Tc-labeled macroaggregated albumin (/sup 99m/Tc-MAA) perfusion studies were carried out in 39 patients with histologically proven primary (four) and metastatic (35) hepatic neoplasms. Three different patterns of tumor perfusion were observed: (1) increased central radioactivity (33%); (2) decreased central radioactivity (33%); and (3) mixed and/or diffuse radioactivity (33%). Extrahepatic perfusion as evidenced by radioactive localization in the region of the stomach, pancreas, and small bowel was noted in 51%. Its presence was associated with a higher incidence of gastrointestinal complications (45% vs. 16%). Tumor arteriovenous shunting was demonstrated in 38%, showing localization of radiotracer activity in the lungs, and decreased as tumors decreased in size. The use of /sup 99m/Tc-MAA infusion studies in intrahepatic arterial chemotherapy offers an excellent evaluation of catheter placement and tumor perfusion, in addition to helping to avoid gastrointestinal complications.

Bledin, A.G.; Kantarjian, H.M.; Kim, E.E.; Wallace, S.; Chuang, V.P.; Patt, Y.Z.; Haynie, T.P.

1982-10-01

330

SPECT measurements with /sup 99m/Tc-HM-PAO in focal epilepsy  

SciTech Connect

The ability of SPECT measurements with (/sup 99m/Tc)-HM-PAO (Ceretec) to find the location of the epileptic focus was studied in patients under consideration for neurosurgical treatment for therapy-resistant focal epilepsy. The location of low (/sup 99m/Tc)-HM-PAO uptake regions found at interictal measurements, and of high (/sup 99m/Tc)-HM-PAO uptake regions found at ictal measurements, was compared to the findings of extensive ictal and interictal EEG examinations, and to the results of CT and MRT. While EEG revealed focal epileptic activity in all of the 14 patients, SPECT showed regional abnormalities in 13 (93%). CT and MRT showed abnormal findings in 30%.

Ryding, E.; Rosen, I.; Elmqvist, D.; Ingvar, D.H.

1988-12-01

331

99Tc and Re incorporated into metal oxide polyoxometalates: oxidation state stability elucidated by electrochemistry and theory.  

PubMed

The radioactive element technetium-99 ((99)Tc, half-life = 2.1 × 10(5) years, ?(-) of 253 keV), is a major byproduct of (235)U fission in the nuclear fuel cycle. (99)Tc is also found in radioactive waste tanks and in the environment at National Lab sites and fuel reprocessing centers. Separation and storage of the long-lived (99)Tc in an appropriate and stable waste-form is an important issue that needs to be addressed. Considering metal oxide solid-state materials as potential storage matrixes for Tc, we are examining the redox speciation of Tc on the molecular level using polyoxometalates (POMs) as models. In this study we investigate the electrochemistry of Tc complexes of the monovacant Wells-Dawson isomers, ?(1)-P(2)W(17)O(61)(10-) (?1) and ?(2)-P(2)W(17)O(61)(10-) (?2) to identify features of metal oxide materials that can stabilize the immobile Tc(IV) oxidation state accessed from the synthesized Tc(V)O species and to interrogate other possible oxidation states available to Tc within these materials. The experimental results are consistent with density functional theory (DFT) calculations. Electrochemistry of K(7-n)H(n)[Tc(V)O(?(1)-P(2)W(17)O(61))] (Tc(V)O-?1), K(7-n)H(n)[Tc(V)O(?(2)-P(2)W(17)O(61))] (Tc(V)O-?2) and their rhenium analogues as a function of pH show that the Tc-containing derivatives are always more readily reduced than their Re analogues. Both Tc and Re are reduced more readily in the lacunary ?1 site as compared to the ?2 site. The DFT calculations elucidate that the highest oxidation state attainable for Re is VII while, under the same electrochemistry conditions, the highest oxidation state for Tc is VI. The M(V)? M(IV) reduction processes for Tc(V)O-?1 are not pH dependent or only slightly pH dependent suggesting that protonation does not accompany reduction of this species unlike the M(V)O-?2 (M = (99)Tc, Re) and Re(V)O-?1 where M(V/IV) reduction process must occur hand in hand with protonation of the terminal M?O to make the ?*(M?O) orbitals accessible to the addition of electrons. This result is consistent with previous extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) data that reveal that the Tc(V) is "pulled" into the -?1 framework and that may facilitate the reduction of Tc(V)O-?1 and stabilize lower Tc oxidation states. This study highlights the inequivalency of the two sites, and their impact on the chemical properties of the Tc substituted in these positions. PMID:22839965

McGregor, Donna; Burton-Pye, Benjamin P; Mbomekalle, Israel M; Aparicio, Pablo A; Romo, Susanna; López, Xavier; Poblet, Josep M; Francesconi, Lynn C

2012-08-20

332

Radiochemical studies of 99mTc complexes of modified cysteine ligands and bifunctional chelating agents.  

PubMed

The synthesis of four novel ligands using the amino-acid cysteine and its ethyl carboxylate derivative is described. The synthetic method involves a two-step procedure, wherein the intermediate Schiff base formed by the condensation of the amino group of the cysteine substrate and salicylaldehyde is reduced to give the target ligands. The intermediates and the final products were characterized by high resolution nuclear magnetic resonance spectroscopy. Complexation studies of the ligands with 99mTc were optimized using stannous tartrate as the reducing agent under varying reaction conditions. The complexes were characterized using standard quality control techniques such as thin layer chromatography, paper electrophoresis, and paper chromatography. Lipophilicities of the complexes were estimated by solvent extraction into chloroform. Substantial changes in net charge and lipophilicity of the 99mTc complexes were observed on substituting the carboxylic acid functionality in ligands I and II with the ethyl carboxylate groups (ligands II and IV). All the ligands formed 99mTc complexes in high yield. Whereas the complexes with ligands I and II were observed to be hydrophilic in nature and not extractable into CHCl3, ligands III and IV resulted in neutral and lipophilic 99mTc complexes. The 99mTc complex with ligand II was not stable and on storage formed a hydrophilic and nonextractable species. The biodistribution of the complexes of ligands I and II showed that they cleared predominantly through the kidneys, whereas the complexes with ligands III and IV were excreted primarily through the hepatobiliary system. No significant brain uptake was observed with the 99mTc complexes with ligands III and IV despite their favorable properties of neutrality, lipophilicity, and conversion into a hydrophilic species. These ligands offer potential for use as bifunctional chelating agents. PMID:10473195

Pillai, M R; Kothari, K; Banerjee, S; Samuel, G; Suresh, M; Sarma, H D; Jurisson, S

1999-07-01

333

The Peptidomimetic CXCR4 Antagonist TC14012 Recruits ?-Arrestin to CXCR7  

PubMed Central

CXCR7 is an atypical chemokine receptor that signals through ?-arrestin in response to agonists without detectable activation of heterotrimeric G-proteins. Its cognate chemokine ligand CXCL12 also binds CXCR4, a chemokine receptor of considerable clinical interest. Here we report that TC14012, a peptidomimetic inverse agonist of CXCR4, is an agonist on CXCR7. The potency of ?-arrestin recruitment to CXCR7 by TC14012 is much higher than that of the previously reported CXCR4 antagonist AMD3100 and differs only by one log from that of the natural ligand CXCL12 (EC50 350 nm for TC14012, as compared with 30 nm for CXCL12 and 140 ?m for AMD3100). Moreover, like CXCL12, TC14012 leads to Erk 1/2 activation in U373 glioma cells that express only CXCR7, but not CXCR4. Given that with TC14012 and AMD3100 two structurally unrelated CXCR4 antagonists turn out to be agonists on CXCR7, this likely reflects differences in the activation mechanism of the arrestin pathway by both receptors. To identify the receptor domain responsible for these opposed effects, we investigated CXCR4 and CXCR7 C terminus-swapping chimeras. Using quantitative bioluminescence resonance energy transfer, we find that the CXCR7 receptor core formed by the seven-transmembrane domains and the connecting loops determines the agonistic activity of both TC14012 and AMD3100. Moreover, we find that the CXCR7 chimera bearing the CXCR4 C-terminal constitutively associates with arrestin in the absence of ligands. Our data suggest that the CXCR4 and CXCR7 cores share ligand-binding surfaces for the binding of the synthetic ligands, indicating that CXCR4 inhibitors should be tested also on CXCR7. PMID:20956518

Gravel, Stephanie; Malouf, Camille; Boulais, Philip E.; Berchiche, Yamina A.; Oishi, Shinya; Fujii, Nobutaka; Leduc, Richard; Sinnett, Daniel; Heveker, Nikolaus

2010-01-01

334

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

335

Hyperfine anomalies of 95Tc-96Tc and 106Agm- 110Agm using brute-force nuclear magnetic resonance on oriented nuclei  

NASA Astrophysics Data System (ADS)

Brute-force nuclear magnetic resonance on oriented nuclei (BF-NMRON) experiments have been performed with 12 T maximum field and at 10 mK. The resonances for 95,96TcNb, 106AgmAg, and 110AgmAg have been observed. The magnetic moment of 106Agm was determined to be 3.705(4) ?N. Comparing the resonance frequencies of BF-NMRON and those of the known NMR-ON results in Fe, the hyperfine anomalies in Fe were determined: 95?96(Tc)=-0.026(17)%, 106m?110m(Ag)=0.10(6)%. The measured hyperfine anomalies are interpreted in terms of a microscopic theory including core polarization and exchange current effects.

Ohya, S.; Sato, H.; Izumikawa, T.; Goto, J.; Muto, S.; Nishimura, K.

2001-04-01

336

Microwave-assisted synthesis of organometallic complexes of ??mTc(CO)? and Re(CO)?: its application to radiopharmaceuticals.  

PubMed

(99m)Tc-tricarbonyl [(99m)Tc(CO)(3)] complexes have been conventionally synthesized by heating [(99m)Tc(CO)(3)(H(2)O)(3)](+) and a tridentate chelating ligand under atmospheric pressure; however, this method is poor in terms of chemical yield and reproducibility. Moreover, since the half-life of (99m)Tc is very short (6 h), the development of facile and rapid methods of synthesizing (99m)Tc-labeled compounds, which could be used as radioactive tracers for single photon emission computed tomography (SPECT), is required. Thus, we initiated a study on the application of a microwave reaction to the synthesis of (99m)Tc(CO)(3)-2-picolylamine monoacetic acid (PAMA) [(99m)Tc(CO)(3)-PAMA] complexes on the basis of the fact that synthesis of metal complexes proceeds rapidly by microwave irradiation owing to an efficient exothermic phenomenon and heat conduction effect. Formation of by-products could be markedly suppressed by comparison with that in conventional methods. In the present study, rhenium (Re), an element belonging to the same group in the periodic table as technetium (Tc), and which also forms bipyramidal complexes, was first used to investigate the synthetic reaction because no stable isotopes exist for Tc. As a result, when water was used as the solvent under the irradiation of microwaves within 1 min, the Re(CO)(3)-PAMA complex could be directly synthesized from ethyl ester of PAMA (PAMAEE) and [Re(CO)(3)(H(2)O)(3)]Br in one step and with a high yield (94%). Finally, the (99m)Tc(CO)(3)-PAMA complex was successfully synthesized at a high radiochemical yield (>99%) within 1 min of reaction using (99m)Tc instead of Re under the same conditions. PMID:22223378

Kimura, Hiroyuki; Mori, Daisuke; Harada, Naoya; Ono, Masahiro; Ohmomo, Yoshiro; Kajimoto, Tetsuya; Kawashima, Hidekazu; Saji, Hideo

2012-01-01

337

Asialoglycoprotein receptor scintigraphy with 99mTc-galactosyl human serum albumin (99mTc-GSA) as an early predictor of survival in acute liver failure.  

PubMed

This study evaluated the usefulness of asialoglycoprotein receptor scintigraphy with 99mTc-galactosyl human serum albumin (99mTc-GSA scintigraphy) as an early predictor for prognosis of acute liver failure. Forty-eight patients with acute liver failure and without a past history of chronic liver disease were enrolled. Patients were divided into survival and non-survival groups by 28-day mortality. 99mTc-GSA scintigraphy to detect uptake ratio of the heart at 15 minutes to that at three minutes (HH15) and uptake ratio of the liver at 15 minutes to the liver plus the heart at 15 minutes (LHL15), and measurements of serum total bilirubin, hepatocyte growth factor and prothrombin time were performed immediately after the diagnosis of acute liver failure. Areas under the receiver operating characteristic curves were used to compare the prognostic ability of total bilirubin, hepatocyte growth factor, prothrombin time, HH15 ratio, LHL15 ratio and the model for end-stage liver disease score. Clinical characteristics of patients in the survival group (n=20) and in the non-survival group (n=28) were not significantly different. HH15 and LHL15 uptake ratios in the survival group were 0.670 and 0.875, and they were significantly lower and higher than those in the non-survival group, respectively. All patients with LHL15 <0.760 died, and the area under the receiver operating characteristic curve for LHL15 were significantly larger than the areas under the receiver operating characteristic curves of serum variables and model for end-stage liver disease score. In summary, in patients with acute liver failure without chronic liver disease, HH15 and LHL15 of 99mTc-GSA scintigraphy are more useful variables in predicting prognosis than serum variables and model for end-stage liver disease score. PMID:23808513

Tatsumi, H; Masuda, Y; Imaizumi, H; Yoshida, S; Goto, K; Yama, N; Mizuguchi, T; Hirata, K

2013-07-01

338

Failure to diagnose cardiac treatment rejection with Tc99m-PYP images  

SciTech Connect

The possibility of diagnosing transplant rejection using Tc-99m-PYP imaging was examined in 12 cardiac transplant recipients. Two patients were studied on two occasions. The presence or absence of active rejection was established by endomyocardial biopsy. The intensity and pattern of myocardial uptake of the tracer did not differ significantly in the two patients studied at the time of rejection compared to the remainder. It is concluded that a single Tc-99m-PYP study cannot be used to diagnose cardiac transplant rejection.

McKillop, J.H.; McDougall, I.R.; Goris, M.L.; Mason, J.W.; Reitz, B.A.

1981-08-01

339

(99m)Tc-methylene diphosphonate bone scintigraphy findings in posttransplant distal limb syndrome.  

PubMed

We report a case of posttransplant distal limb syndrome (PTDLS) representing a rare complication in kidney transplant recipients characterized by a pain syndrome of the distal extremities. A 68-year-old man with a history of kidney transplantation presented with symmetrical and incapacitating pain in the feet and knees and underwent whole-body Tc-methylene diphosphonate (MDP) scintigraphy for further evaluation. Planar scintigraphy demonstrated marked tracer uptake in the distal femoral and tibial epiphyses, and magnetic resonance imaging showed corresponding osteoedema. Tc-MDP scintigraphy is a valuable tool for evaluation of the etiology of musculoskeletal pain and may demonstrate typical findings in case of PTDLS. PMID:24873782

Derlin, Thorsten; Busch, Jasmin D; Bannas, Peter

2014-07-01

340

First-principles prediction of the equation of state for TcC with rocksalt structure  

NASA Astrophysics Data System (ADS)

The equation of state of TcC with rocksalt structure is investigated by means of first-principles density functional theory calculations combined with the quasi-harmonic Debye model in which the phononic effects are considered. Particular attention is paid to the predictions of the compressibility, the isothermal bulk modulus and its first pressure derivative which play a central role in the formulation of approximate equations of state for the first time. The properties of TcC with rocksalt structure are summarized in the pressure range of 0-80 GPa and the temperature up to 2500 K.

Sun, Xiao-Wei; Chu, Yan-Dong; Liu, Zi-Jiang; Song, Ting; Tian, Jun-Hong; Wei, Xiao-Ping

2014-10-01

341

Diamagnetism of YBa2Cu3O6+x crystals above Tc: Evidence for Gaussian fluctuations  

NASA Astrophysics Data System (ADS)

The magnetization of three high-quality single crystals of YBa2Cu3O6+x, from slightly overdoped to heavily underdoped, has been measured using torque magnetometry. Striking effects in the angular dependence of the torque for the two underdoped crystals, a few degrees above the superconducting transition temperature (Tc), are described well by the theory of Gaussian superconducting fluctuations using a single adjustable parameter. The data at higher temperatures (T) are consistent with a strong cutoff in the fluctuations for T?1.1Tc. Numerical estimates suggest that inelastic scattering could be responsible for this cutoff.

Kokanovi?, I.; Hills, D. J.; Sutherland, M. L.; Liang, R.; Cooper, J. R.

2013-08-01

342

Choledochal cyst with bile duct dilatation: sonography and /sup 99m/Tc IDA cholescintigraphy  

SciTech Connect

Three cases of choledochal cyst associated with intrahepatic biliary dilatation are presented. Findings on sonography included a large cystic mass in the porta hepatis separate from the gallbladder; a dilated common hepatic or common bile duct entering directly into the cyst; and smaller cystic masses of dilated central intrahepatic ducts. All three patients underwent operation with intraoperative cholangiography. Two patients had /sup 99m/Tc IDA cholescintigraphy which confirmed the diagnosis of choledochal cyst by demonstrating filling of the cyst with stasis and delayed intestinal activity. The accurate preoperative diagnosis of choledochal cyst, made by sonography combined with /sup 99m/Tc IDA cholescintigraphy, obviated invasive studies.

Han, B.K.; Babcock, D.S.; Gelfand, M.H.

1981-06-01

343

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

344

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

345

Preliminary dosimetry investigation of Tc-99m diagnostic radionuclide by NIPAM gel dosimeter  

NASA Astrophysics Data System (ADS)

The N-isopropylacrylamide (NIPAM) gel dosimeter was investigated as a suitable material for measuring absorbed doses from radionuclide sources. In this study, NIPAM gel dosimeter was used to evaluate the dose distributions of the Tc-99m radionuclide in NIPAM gel. The accumulated radioactivity range of the Tc-99m NIPAM gel is from approximately 0 MBq to 13.6 MBq (about 0.37 mCi). The NIPAM gel dosimeter with high stability and high-dose linear and non-energy dependent properties can provide various radiopharmaceutical activity intensities in the conduct of dose assessment in nuclear medicine, thereby producing the most promising dose verification tools.

Huang, You-Ruei; Chang, Yuan-Jen; Hsieh, Ling-Ling; Yu, Bi-Wei; Chu, Chien-Hau; Hsieh, Bor-Tsung

2013-06-01

346

Pulsed laser deposition of high Tc superconducting thin films: Present and future  

SciTech Connect

Pulsed laser deposition (PLD) has been widely used for deposition of high {Tc} superconducting thin films, and has been approved as one of the best physical vapor techniques to prepare the films. The most important advantage of this technique is stoichiometric deposition, namely the films could be made with the same composition of the targets. Utilized PLD, not only thin films but also multilayers and superlattices of high {Tc} superconductors have been fabricated. In this paper, the performance of the technique will be reviewed, and the future will be speculated.

Wu, X.D.; Muenchausen, R.E.; Foltyn, S.; Estler, R.C.; Dye, R.C.; Garcia, A.R.; Nogar, N.S. (Los Alamos National Lab., NM (USA)); Venkatesan, T.; Chang, C.C.; Ramesh, R.; Hwang, M.; Nazar, L.; Wilkens, B.; Schwarz, S.A.; Ravi, R.T.; Barner, J.B.; England, P.; Rogers, C.T.; Tarascon, J.M. (Bellcore, Red Bank, NJ (USA)); Inam, A.; Xi, X.X.; Li, Q. (Rutgers--the State Univ., Piscataway, NJ (USA). Dept. of Physics and

1990-01-01

347

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

348

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

349

Continuous and reversible operation of Bi2212 based THz emitters just below Tc  

NASA Astrophysics Data System (ADS)

Continuous and reversible operation of the THz-light emitters comprised of the intrinsic Josephson junction (iJJ) system of high- Tc superconductor BiSrCaCuO (Bi2212) is reported. This reversible emission is observed in samples made of lightly underdoped crystals when a part of the mesa device is so overheated by Joule heating that the temperature reaches Tm near but still below Tc, while the irreversible type of emission occurs at less overheated condition. The large temperature gradient in the mesa due to overheating under high bias currents seems to be responsible for the new observed reversible emission.

Minami, Hidetoshi; Orita, Naoki; Koike, Takashi; Yamamoto, Takashi; Kadowaki, Kazuo

350

Continuous and reversible operation of Bi2212 based THz emitters just below Tc  

NASA Astrophysics Data System (ADS)

Continuous and reversible operation of the THz-light emitters comprised of the intrinsic Josephson junction (iJJ) system of high-Tc superconductor BiSrCaCuO (Bi2212) is reported. This reversible emission is observed in samples made of lightly underdoped crystals when a part of the mesa device is so overheated by Joule heating that the temperature reaches Tm near but still below Tc, while the irreversible type of emission occurs at less overheated condition. The large temperature gradient in the mesa due to overheating under high bias currents seems to be responsible for the new observed reversible emission.

Minami, Hidetoshi; Orita, Naoki; Koike, Takashi; Yamamoto, Takashi; Kadowaki, Kazuo

2010-12-01

351

Numerical analyses of levitation force and flux creep on high [Tc] superconductor  

SciTech Connect

Large levitation force and a stable equilibrium are obtained with a permanent magnet and a bulk high [Tc] superconductor (HTSC). Evaluation of the levitation force is important for many applications, such as magnetically levitated vehicles, magnetic bearing, flywheel and linear drive. Levitation force between a permanent magnet and a high [Tc] superconductor is examined by using two numerical methods. The levitation force to vertical direction is calculated by using the critical state model. Stiffness of restoring force to horizontal direction is calculated by using a frozen-in field model. Numerical solutions agree well with experimental results. Dynamic properties of the levitation force are also analyzed by combining the two methods.

Tsuchimoto, M.; Kojima, T.; Takeuchi, H.; Honma, T. (Hokkaido Univ., Sapporo (Japan). Dept. of Electrical Engineering)

1993-11-01

352

Distinctive Features of Novel Superconducting Transitions in Underdoped and Overdoped HIGH-Tc Cuprates  

NASA Astrophysics Data System (ADS)

It is argued that the new theory that combines the precursor BCS-like non-superconducting (SC) pairing and the Cooper-pair condensation into a superfluid Bose-liquid state is more plausible than the standard SC fluctuation approach in describing the distinctive features of the underdoped and overdoped high-Tc cuprates. We show that the scenarios for high-Tc superconductivity in these materials are quite different on the character of the Cooper-pair formation and SC phase transitions.

Dzhumanov, S.; Fan, J. D.

353

Meckel's diverticulum findings on Tc-99m red blood cell scintigraphy in a bleeding leukemic patient confirmed by Tc-99m pertechnetate scintigraphy.  

PubMed

A 25-year-old Caucasian woman with a medical history of acute promyelocytic leukemia presented to the emergency department with massive gastrointestinal bleeding. A bone marrow biopsy excluded hemorrhagic leukemia. Esophagogastroduodenoscopy, colonoscopy, emergency abdominal angiography, abdominal CT scan, and wireless capsule endoscopy were performed but no source of bleeding could be detected. Tc-99m RBC scintigraphy was consistent with a small bowel bleeding focus. The persistent and focal images in the right abdomen were suggestive of Tc-99m RBC trapping in the lumen of a Meckel diverticulum (MD). In accordance with this suspicion, successive Tc-99m pertechnetate scintigraphy was performed after 3 days, consistent with the diagnostic hypothesis. Due to the persisting severe bleeding (with a drop in baseline hemoglobin from 10.4 to 7.1 g/dL), despite 8 units of blood transfusion, emergency surgery was performed. Through a minilaparotomy a segmental small bowel resection, including Meckel diverticulum, was performed. The postoperative course was uneventful. PMID:17667451

Ciccoritti, L; Valenza, V; Pierconti, F; Di Giuda, D; D'Errico, G; Antinori, A; Crucitti, A

2007-08-01

354

Cu-free 1,3-dipolar cycloaddition click reactions to form isoxazole linkers in chelating ligands for fac-[M(I)(CO)3]+ centers (M = Re, 99mTc).  

PubMed

Isoxazole ring formation was examined as a potential Cu-free alternative click reaction to Cu(I)-catalyzed alkyne/azide cycloaddition. The isoxazole reaction was explored at macroscopic and radiotracer concentrations with the fac-[M(I)(CO)3](+) (M = Re, (99m)Tc) core for use as a noncoordinating linker strategy between covalently linked molecules. Two click assembly methods (click, then chelate and chelate, then click) were examined to determine the feasibility of isoxazole ring formation with either alkyne-functionalized tridentate chelates or their respective fac-[M(I)(CO)3](+) complexes with a model nitrile oxide generator. Macroscale experiments, alkyne-functionalized chelates, or Re complexes indicate facile formation of the isoxazole ring. (99m)Tc experiments demonstrate efficient radiolabeling with click, then chelate; however, the chelate, then click approach led to faster product formation, but lower yields compared to the Re analogues. PMID:24483834

Bottorff, Shalina C; Kasten, Benjamin B; Stojakovic, Jelena; Moore, Adam L; MacGillivray, Leonard R; Benny, Paul D

2014-02-17

355

Magnetic flux motion and its influence on transport properties of the high T(c) oxide superconductors  

Microsoft Academic Search

High T(c) superconductors exhibit significant flux motion due to a thermally activated creep process. The motion of the fluxoids dissipates energy. This dissipation causes a broadening of the resistive transition below T(c) in a magnetic field as well as a logarithmic decay of the diamagnetic shielding moment in time. From the detailed structure of the broadened transition, empirical parameters are

J. Z. Sun; K. Char; M. R. Hahn; T. H. Geballe; A. Kapitulnik

1989-01-01

356

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 23, NO. 3, JUNE 2013 1600705 High-Tc DC SQUIDs for Magnetoencephalography  

E-print Network

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 23, NO. 3, JUNE 2013 1600705 High-Tc DC SQUIDs interference device (SQUID) magnetometers intended for magnetoencephalography (MEG) measurement systems. The high-Tc SQUID magnetometers also incorporate 16 mm multilayer superconducting flux transformers

Dunin-Borkowski, Rafal E.

357

Development of Tyrosine-Based Radiotracer 99mTc-N4-Tyrosine for Breast Cancer Imaging  

PubMed Central

The purpose of this study was to develop an efficient way to synthesize 99mTc-O-[3-(1,4,8,11-tetraazabicyclohexadecane)-propyl]-tyrosine (99mTc-N4-Tyrosine), a novel amino acid-based radiotracer, and evaluate its potential in breast cancer gamma imaging. Precursor N4-Tyrosine was synthesized using a 5-step procedure, and its total synthesis yield was 38%. It was successfully labeled with 99mTc with high radiochemical purity (>95%). Cellular uptake of 99mTc-N4-Tyrosine was much higher than that of 99mTc-N4 and the clinical gold standard 18F-2-deoxy-2-fluoro-glucose (18F-FDG) in rat breast tumor cells in vitro. Tissue uptake and dosimetry estimation in normal rats revealed that 99mTc-N4-Tyrosine could be safely administered to humans. Evaluation in breast tumor-bearing rats showed that although 99mTc-N4-Tyrosine appeared to be inferior to 18F-FDG in distinguishing breast tumor tissue from chemical-induced inflammatory tissue, it had high tumor-to-muscle uptake ratios and could detect breast tumors clearly by planar scintigraphic imaging. 99mTc-N4-Tyrosine could thus be a useful radiotracer for use in breast tumor diagnostic imaging. PMID:22496612

Kong, Fan-Lin; Ali, Mohammad S.; Rollo, Alex; Smith, Daniel L.; Zhang, Yinhan; Yu, Dong-Fang; Yang, David J.

2012-01-01

358

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

359

Sentinel lymph node accumulation of Lymphoseek and Tc-99m-sulfur colloid using a "2-day" protocol?  

PubMed Central

Lymphoseek is a receptor-binding radiopharmaceutical specifically designed for sentinel lymph node (SLN) mapping. We conducted a clinical trial which measured the injection site clearance and sentinel lymph node accumulation after a single intradermal injection of Lymphoseek or unfiltered [99mTc]sulfur colloid (TcSC) using a “2-day” protocol for SLN mapping of breast cancer. Eleven patients with breast cancer participated in this study. Five patients received an intradermal administration of 1.0 nmol of 99mTc-labeled Lymphoseek; SLN mapping was performed on four subjects within 19 to 27 h. Six subjects received an intradermal administration of TcSC; SLN mapping was performed on five subjects within 18 to 26 h. Lymphoseek exhibited a significantly (P<.001) faster injection site clearance than TcSC. The mean Lymphoseek clearance half-time was 2.18±1.09 h compared to 57.4±92.8 h for TcSC. The mean sentinel lymph node uptake of Lymphoseek (1.5±1.7%) and TcSC (3.5±3.1%) was statistically equivalent (P=.213). When an intradermal injection is employed, Lymphoseek demonstrated faster injection site clearance than unfiltered [99mTc]sulfur colloid and persistent SLN accumulation for at least 24 h. PMID:19647175

Wallace, Anne M.; Hoh, Carl K.; Limmer, Karl K.; Darrah, Denise D.; Schulteis, Gery; Vera, David R.

2014-01-01

360

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

361

Role of 99mTc-ECD SPECT in the Management of Children with Craniosynostosis  

PubMed Central

Purpose of the Report. There is a paucity of data on correlation of various imaging modalities with clinical findings in craniosynostosis. Moreover, no study has specifically reported the role of 99mTc-ECD SPECT in a large number of subjects with craniosynostosis. Materials and Methods. We prospectively analyzed a cohort of 85 patients with craniosynostosis from year 2007 to 2012. All patients underwent evaluation with 99mTc-ECD SPECT and the results were correlated with radiological and surgical findings. Results. 99mTc-ECD SPECT revealed regional perfusion abnormalities in the cerebral hemisphere corresponding to the fused sutures preoperatively that disappeared postoperatively in all the cases. Corresponding to this, the mean mental performance quotient (MPQ) increased significantly (P?Tc-ECD SPECT study) are beneficial, as theylead to improved MPQ after surgery. PMID:24987670

Barik, Mayadhar; Bajpai, Minu; Das, Rashmi Ranajn; Malhotra, Arun; Panda, Shasanka Shekhar; Sahoo, Manas Kumar; Dwivedi, Sadanand

2014-01-01

362

TC10 controls human myofibril organization and is activated by the sarcomeric RhoGEF obscurin.  

E-print Network

1 TC10 controls human myofibril organization and is activated by the sarcomeric RhoGEF obscurin signaling in myofibrillogenesis Keywords: Myofibrillogenesis, Rho GTPase, Obscurin inserm-00366941,version1 skeletal myoblasts and it is active in differentiated myotubes. We identify obscurin, a sarcomere

Boyer, Edmond

363

Ectopic thoracic kidney: evaluation using 99mTc dimercaptosuccinic acid SPECT-CT.  

PubMed

Ectopic thoracic kidney is a very rare congenital defect and is usually diagnosed incidentally. 99mTc-dimercaptosuccinic acid SPECT-CT images of a 7-year-old boy with left ectopic thoracic kidney are presented here. PMID:22691527

Singh, Harmandeep; Sharma, Punit; Nazar, Aftab Hasan; Das, Kalpajyoti; Naswa, Niraj; Singla, Suhas; Kumar, Rakesh

2012-07-01

364

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

365

Guidelines for the labelling of leucocytes with 99mTc-HMPAO  

PubMed Central

We describe here a protocol for labelling autologous white blood cells with 99mTc-HMPAO based on previously published consensus papers and guidelines. This protocol includes quality control and safety procedures and is in accordance with current European Union regulations and International Atomic Energy Agency recommendations. PMID:20198473

de Vries, Erik F. J.; Roca, Manel; Jamar, Francois; Israel, Ora

2010-01-01

366

Polar Kerr effect in high-Tc superconductors - The rotating-plate technique  

Microsoft Academic Search

A technique for measuring the complex polar Kerr rotation in high-Tc superconductors is discussed using a Jones matrix approach. It is concluded that this technique provides excellent discrimination against linear polarization effects, but remains sensitive to reciprocal signal due to sample inhomogeneity. While the presence of Kerr ellipticity has been demonstrated in cuprate and bismuthate samples, it cannot be definitely

K. B. Lyons; J. F. Dillon Jr.; M. McGlashan-Powell

1991-01-01

367

Polar Kerr effect in high-Tc superconductors: The rotating-plate technique  

Microsoft Academic Search

A technique recently used for measurement of the complex polar Kerr rotation in high-Tc superconductors is discussed in a tutorial manner, making use of a Jones matrix approach. The primary concern addressed is the rejection of effects caused by linear birefringence and dichroism effects in the sample and associated optical components. This rejection is accomplished by the use of a

K. B. Lyons; J. F. Dillon; M. McGlashan-Powell

1991-01-01

368

Synthesis of a 99mTc Flutamide System for Imaging Androgen Expression in  

E-print Network

Synthesis of a 99mTc Flutamide System for Imaging Androgen Expression in Prostate Cancer K. Tace bennyp@wsu.edu Introduction Approximately 230,000 men in the U.S. are diagnosed with prostate cancer (PC nuclear shuttle protein responsible for testosterone transport into the nucleus. In early stages of PC

Collins, Gary S.

369

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

370

MYELOID NEOPLASIA Perturbed hematopoiesis in the Tc1 mouse model of Down syndrome  

E-print Network

MYELOID NEOPLASIA Perturbed hematopoiesis in the Tc1 mouse model of Down syndrome Kate A. Alford,1 Kingdom Trisomy of human chromosome 21 (Hsa21) results in Down syndrome (DS), a disorder that affects many(14):2928-2937) Introduction Down syndrome (DS) results from trisomy of human chromosome 21 (Hsa21, trisomy 21) and is the most

Li, Zhe

371

Preparation, biodistribution, and scintigraphic evaluation of (99m)Tc-clindamycin: an infection imaging agent.  

PubMed

Bacterial infection is found to be the cause of death throughout the world. Nuclear medicine imaging with the help of radiopharmaceuticals has great potential for treating infections. In the present work, clindamycin, a lincosamide antibiotic, was labeled with technetium-99 m (~380 MBq). Clindamycin has been proven to be efficient for treating serious infections caused by bacteria such as Staphylococcus aureus. Quality control, characterization, biodistribution, and scintigraphy of radiolabeled clindamycin were done, and labeling efficiency was determined by ascending paper chromatography. More than 95 % labeling efficiency with technetium-99 m ((99m)Tc) was achieved at pH 6-7 while using 2.5-3 ?g SnCl2 · H2O as a reducing agent and 100 ?g of ligand at room temperature. The characterization of the compound was performed by using electrophoresis, HPLC and shake flask assay. Electrophoresis indicates the neutral behavior of (99m)Tc-clindamycin. HPLC analysis confirms the single specie of the labeled compound, while shake flask assay confirms high lipophilicity. The biodistribution studies of (99m)Tc-clindamycin were performed Sprague Dawley rats bearing bacterial infection. Scintigraphy and biodistribution studies showed a high uptake of (99m)Tc-clindamycin in the liver, heart, lung, and stomach as well as at S. aureus-infected sites in rabbits. PMID:25113549

Hina, Saira; Rajoka, Muhammad Ibrahim; Roohi, Samina; Haque, Asma; Qasim, Muhammad

2014-10-01

372

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

373

Vortex motion and time dependent magnetic responses in high Tc superconductors  

Microsoft Academic Search

High Tc superconductors are prone to thermal motion of the magnetic vortex lattice when a large macroscopic current is carried under strong magnetic fields because of their small coherence lengths and the relatively high temperatures. By measuring the magnetic relaxation process associated with such dissipation, the thermal activation energy of the vortex motion is extracted over the whole temperature range.

J. Z. Sun; C. B. Eom; B. Lairson; J. C. Bravman; T. H. Geballe; A. Kapitulnik

1989-01-01

374

Carrier-free production of 95Tc at an electron accelerator  

NASA Astrophysics Data System (ADS)

We report on the results of studies of the 95Tc isotope production conditions in a poorly investigated 96Ru(?,N) 95Tc reaction at a relatively inexpensive electron accelerator. Based on the analytical model it is demonstrated the possibility for estimating the effective and peak cross-sections and the isotope yield for a given reaction in a thick production target without preliminary determination of its excitation function. For this purpose we compared specific activities of two small samples that were activated under the same conditions using the reference reaction 68Zn(?,p) 67Cu and the one under investigation. The experiment on simultaneous photo-activation of natural zinc and ruthenium targets was performed followed by the investigation of their isotope composition. The specific activity of the radionuclide was measured and cross-sections for the 96Ru(?,N) 95g,mTc reactions were determined. The yields of desired isomers and admixtures in the natural ruthenium targets of different size were estimated. It is shown, in particular, that the operating conditions of the NSC KIPT accelerator KUT-30 can provide 95gTc yields up to 120 mCi/h.

Aizatskiy, N. I.; Dikiy, N. P.; Dovbnya, A. N.; Lyashko, Yu. V.; Nikiforov, V. I.; Shevchenko, V. A.; Tenishev, A. Eh.; Uvarov, V. L.

2011-12-01

375

Tc99m HMPAO brain perfusion imaging in young Down's syndrome patients  

Microsoft Academic Search

Down's syndrome (DS) is characterized by moderate mental retardation and a variety of abnormalities involving multiple organ systems. There is a high incidence of Alzheimer's disease (AD) type dementia beyond the age of 35. In this study, single photon emission computed tomography (SPECT) brain perfusion imaging of young Down's syndrome patients was performed to define the perfusion pattern. Tc-99m HMPAO

Nahide Gökçora; Tamer Atasever; Ne?e ?lgin Karabacak; Gülin Vural; K?v?lc?m Gücüyener

1999-01-01

376

A new calculating formula of iodometric titration for high Tc superconductors  

Microsoft Academic Search

In order to determine the effective oxidation state of Cu (p) and oxygen content (y) with the iodometric method, a new formula for calculating p and y of high Tc copper oxides is presented here. The formula of p involves a corrective term of 8CV1\\/M1, which reduces a systematic calculating error. With this approach, for YBCO, the value of p

W. M. Chen; J. F. Geng; L. Y. Li; X. Jin; C. C. Lam; L. C. Hung

1996-01-01

377

Estimation of myocardial infarct size in man using 99m Tc polyphosphate  

Microsoft Academic Search

We have critically evaluated the use of 99m Tc polyphosphate to estimate myocardial infarct size. Optimum conditions were first defined with respect to infarct edge definition, and relative activity over infarct and bone and in blood pool. The scintigrams of 53 patients with acute transmural myocardial infarction were recorded under these defined constant conditions and analysed in various ways. Visual

G J Davies; B Fakhrai; A Morgan; J R Muir

1979-01-01

378

REVUE DE PHYSIQUE APPLIQUE Properties of high-Tc superconductors at RF and microwaves  

E-print Network

-Tc superconductors (HTSC) behaviour in RF and microwave electromagnetic field accumulated to this day. The main of the ceramics with p ~ 10-4 03A9 x m. We suggest a model of the HTSC single crystal where the charge carriers be a course of HTSC single crystal residual resistance. A close agreement between experimental data and model

Boyer, Edmond

379

Effective parameters of the band dispersion in n-type high-Tc superconductors  

E-print Network

believed that it is impossible to formulate a complete theory of high-Tc supercon- ductivity (HTSC) in cuprates without under- standing the behavior not only of the hole doped HTSC (p-type cuprates: LSCO, YBCO to the linear dependence in p-type HTSC [3], (iii) the insulating gap in n-type systems is indirect [4] (the

von Oppen, Felix

380

Ulcerative colitis and a bleeding polyp detected on Tc-99m-pertechnetate abdominal scintigraphy  

SciTech Connect

Two children with rectal bleeding were diagnosed as having ulcerative colitis and a bleeding colonic polyp respectively using abdominal scanning with Tc-99m pertechnetate. Early flow studies are recommended with careful attention paid to the amount of time abnormal areas of activity are seen on the abdominal scan.

Howman-Giles, R.

1981-10-01

381

Lung clearance of inhaled /sup 99m/Tc-DTPA in the dog  

SciTech Connect

A study was made of the reproducibility of measuring an index of permeability of respiratory epithelium in dogs using aerosolized /sup 99m/Tc-DTPA (diethylenetriaminepentaacetate). The method uses a gamma camera to measure the rate of clearance of soluble radioactive aerosol deposited in the lung. A solution of /sup 99m/Tc-DTPA in normal saline was aerosolized by an ultrasonic nebulizer. Eleven anesthetized dogs breathing spontaneously inhaled the resulting droplets for 2 min. Mass median aerodynamic diameter of the droplets was 4.4 ..mu..m with a geometric standard deviation of 2.1. Clearance from the lung was monitored by quantitative gamma camera imaging for up to 2 h. For a 60-min observation period, the biological half-life for clearance of /sup 99m/Tc-DTPA from both lungs was 66 +/- 11 (SD) min. Apical regions cleared significantly slower than basal regions, probably because of a larger portion of bronchial tissue in the apical region of the dog's lung. The best reproducibility of absorption of /sup 99m/Tc-DTPA in the dog was obtained from basal regions and peripheral zones of the lung within 30 min after inhalation of the radioaerosol.

Oberdoerster, G.; Utell, M.J.; Weber, D.A.; Ivanovich, M.; Hyde, R.W.; Morrow, P.E.

1984-01-01

382

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

383

Scapular hibernoma fortuitously discovered on myocardial perfusion imaging through Tc-99m tetrofosmin.  

PubMed

A 49-year-old man was hospitalized for precordial pain. The result of a resting electrocardiograph was normal. Tc-99m tetrofosmin stress myocardial imaging was performed and uptake in the area of the left scapula was seen. The abnormality was caused by a subcutaneous tumor. Histologic examination revealed a hibernoma. PMID:11139063

Oller, J D; Gómez, J D; Kortazar, J F; García, J D; Navarro, A A; Albertino, R J; Díaz, J J; Llorente, J A; Andreu, M N; Arcas, R F; Medina, T; Vázquez, R J

2001-01-01

384

Tc-99m MDP bone scintigraphy in a case of Touraine-Solente-Gole syndrome  

PubMed Central

Pachydermoperiostosis is a form of primary hypertrophic osteoarthropathy, also known as Touraine-Solente-Gole syndrome. It is a rare disease. In this report, we present the case of a 29-year-old man with this rare disorder, having significant findings on Tc-99m methylene diphosphonate bone scan. PMID:21969783

Mudalsha, Ravina; Jacob, MJ; Jora, Charu; Pandit, AG

2011-01-01

385

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

386

Labeling of preformed liposomes with Ga-67 and Tc-99m by chelation  

SciTech Connect

We have synthesized a long-chain hydrocarbon covalently coupled to diethylene-triaminepenta-acetic acid (stearylamine-DTPA) and have incorporated this compound in liposomes during their preparation. The lipophilic hydrocarbon chain anchors the molecule in the lipid bilayer, exposing the DTPA groups on the surface for chelation. Ethanolic solutions of the lipids are evaporated to dryness under nitrogen in multidose vials; the lipids are suspended in the vial by adding a small volume of distilled water followed by sonication. The liposomes are then labeled by transcomplexation in the case of Ga-67 and by conventional stannous reduction in the case of Tc-99m, by adding the activities directly to the vial. These liposomes bind 95 +/- 5% of Ga-67 and Tc-99m activity, as determined by paper chromatograph assay, eliminating the need for a purification step. The labeled liposomes release about 5% of their Ga-67 activity, and about 30% of their Tc-99m activity after 2 hr of incubation in 50% human plasma at 37 degrees C. Activity released from liposomes labeled with Ga-67 or Tc-99m oxine is much greater under the same conditions. In normal mice the labeled liposomes show biodistributions that are comparable with that obtained with liposomes labeled by conventional techniques.

Hnatowich, D.J.; Friedman, B.; Clancy, B.; Novak, M.

1981-09-01

387

Precise and imprecise somatic excision of the transposon Tc1 in the nematode C. elegans.  

PubMed Central

Eleven chromosomal products of somatic excision of Tc1 transposable elements have been cloned and sequenced. The cloning method did not involve genetic reversion; therefore the products analyzed should be representative. Six empty religated target sites were from excision of one Tc1 element inserted near actin genes on linkage group V; five were from a second Tc1 element inserted elsewhere on the same linkage group. All six products from the first element were identical in sequence to an empty target site from a second strain, indicating excision had been precise. Two of the products from the second element were also precise, whereas the other three contained four extra nucleotides at the point of excision, indicating an imprecise excision. The four nucleotides are the same in all cases and could represent two terminal nucleotides of the transposon plus a two-nucleotide target site duplication. The difference in the ratio of precise to imprecise excision at the two insertion sites suggests a possible chromosomal position effect on the pathway of Tc1 somatic excision. Images PMID:2821484

Ruan, K S; Emmons, S W

1987-01-01

388

Cupric oxide as an induced-multiferroic with high-TC  

E-print Network

LETTERS Cupric oxide as an induced-multiferroic with high-TC T. KIMURA1 *, Y. SEKIO1 , H. NAKAMURA1 order are termed `magnetoelectric multiferroics'1­4 . In the past few years, a new class of such materials, `induced- multiferroics', has been discovered5,6 , wherein non-collinear spiral magnetic order

Chandra, Premi

389

Lung function declines in patients with pulmonary sarcoidosis and increased respiratory epithelial permeability to sup 99m Tc-DTPA  

SciTech Connect

Respiratory epithelial clearance of {sup 99m}Tc-DTPA (RC-Tc-DTPA) and pulmonary function tests (PFT) were determined at intervals of 6 or 12 months in 37 untreated, nonsmoking patients with sarcoidosis over a period of 6 to 36 months. PFT included the measurements of total lung capacity (TLC), vital capacity (VC), FEV1, and diffusing capacity for carbon monoxide. No difference was found between the respiratory clearance of {sup 113m}In-DTPA (2.25 +/- 1.00%/min) and RC-Tc-DTPA (2.29 +/- 1.11%/min) in eight patients with pulmonary sarcoidosis. Pulmonary function decreased 15% or more in at least 2 function tests during 11 follow-up periods, but it remained stable during 47 follow-up periods. In patients whose lung function deteriorated, RC-Tc-DTPA increased to 3.51 +/- 1.55%/min; in contrast, in patients whose lung function remained stable, regardless of the initial values, RC-Tc-DTPA was normal (1.00 +/- 0.50%/min; p less than 0.001). In eight patients who were treated with corticosteroids, RC-Tc-DTPA decreased from 3.48 +/- 1.31%/min to 1.56 +/- 0.64%/min (p less than 0.001), and PFT improved. We conclude that in nonsmokers with pulmonary sarcoidosis, increased RC-Tc-DTPA is not related to dissociation of 99mTc from DTPA, RC-Tc-DTPA is increased when pulmonary function decreases, and, when increased, RC-Tc-DTPA decreases with corticosteroid therapy.

Chinet, T.; Dusser, D.; Labrune, S.; Collignon, M.A.; Chretien, J.; Huchon, G.J. (Universite Rene Descartes, Paris (France))

1990-02-01

390

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

391

Second Generation ROVSecond Generation ROV Mikhail Dembicki  

E-print Network

Second Generation ROVSecond Generation ROV By: Mikhail Dembicki Margaret Boshek Hornet II #12;Second Generation ROVSecond Generation ROV By: Mikhail Dembicki Margaret Boshek 7/22/03 Hornet IIHornet.5.2 Pictures of ROV CD 2 8.6 Electronic copy of this Report CD 1 #12;Executive Summary Remotely operated

Wood, Stephen L.

392

Evolution of structural perfections in high Tc superconducting thin film  

NASA Astrophysics Data System (ADS)

In this dissertation work, I developed a forensic methodology to investigate the evolution of chemistry and superconductivity in a heteroepitaxial thin film system---YBa2Cu3O6+x (YBCO). Misfit lattice of a YBCO thin film and its substrate results in coherency strain that dictates the generation of oxygen deficiency and structural defects, which is eventually manifested in the superconductivity or normal state properties. To understand the dynamic process of such evolution, in my retrospective approach, a thicker film is stripped thinner step by step and then compared with an as-grown film of equal thickness. Through such one-to-one comparison, I succeeded in characterizing the effects of strain, partial strain-relaxation, and complete strain-relaxation on the chemistry and physics of thin film cuprate high temperature superconductors as probed by various analytical tools.

Seo, Hye-Won

393

Kinetics of reactions of Np and Pu with hydrazine derivatives: XIII. Catalysis by Tc(VII) of the reaction between Pu(IV) and 2-hydroxyethylhydrazine  

SciTech Connect

The mechanisms of the catalysts by TC(VII) of the reaction between Pu(IV) and 2-hydroxyethylhydrazine includes slow steps for the reduction of Tc(VII) to Tc(IV) by 2-hydroxyethylhydrazine and oxidation of Tc(IV) by Pu(IV). Numerical processing of the experimental data using a computer yielded the kinetic equations and the rate constants and activation energies of these reaction steps.

Koltunov, V.S.; Zhuravleva, G.I.; Shapovalov, M.P.

1994-07-01

394

Novel [(99m)Tc(III)(PS)2(Ln)] Mixed-Ligand Compounds (PS = Phosphino-thiolate; L = Dithiocarbamate) Useful in Design and Development of Tc(III)-Based Agents: Synthesis, in Vitro, and ex Vivo Biodistribution Studies.  

PubMed

A general procedure for the preparation of a new class of neutral six-coordinated mixed ligand [(99m)Tc(III)(PS)2(Ln)] compounds (PS = trisalkyl-phosphino-thiolate; Ln = dithiocarbamate) is reported as well as their in vitro stability and the ex vivo tissue distribution studies. [(99m)Tc(PS)2(Ln)] complexes were prepared in high yield in nearly physiologic conditions following a one-pot procedure. For instance, the chemical identity of [(99m)Tc(PSiso)2(L1)] (PSiso = 2-(diisopropylphosphino)ethanethiol; L1 = pyrrolidine dithiocarbamate) was determined by HPLC comparison with the corresponding (99g)Tc-complex. All complexes comprise the stable [(99m)Tc(III)(PS)2](+) moiety, where the remaining two coordination positions are saturated by a dithiocarbamate chelate, also carrying bioactive molecules (e.g., 2-methoxyphenylpiperazine). [(99m)Tc(PS)2(Ln)] complexes were inert toward ligand exchange reactions. No significant in vitro and in vivo biotransformation were observed, underlining their remarkable thermodynamic stability and kinetic inertness. These results could be conveniently utilized to devise a novel class of (99m)Tc(III)-based compounds useful in radiopharmaceutical applications. PMID:25333249

Salvarese, Nicola; Morellato, Nicolò; Rosato, Antonio; Meléndez-Alafort, Laura; Refosco, Fiorenzo; Bolzati, Cristina

2014-11-13

395

New technetium-99m generator technologies utilizing polyethylene glycol-based aqueous biphasic systems  

SciTech Connect

Two new schemes for TcO{sub 4}{sup {minus}}/MoO{sub 4}{sup 2{minus}} separations from OH{sup {minus}} and MoO{sub 4}{sup 2{minus}} media using polyethylene glycol (PEG)-based aqueous biphasic systems (ABS) have been developed. The two most important salt solutions in current {sup 99m}Tc-generator technologies, OH{sup {minus}} and MoO{sub 4}{sup 2{minus}}, also salt out PEG to form ABS. In liquid/liquid PEG- ABS, pertechnetate can be separated from molybdate with separation factors as high as 10,000. Stripping is accomplished by reduction of the TcO{sub 4}{sup {minus}} and back extraction into a salt solution. the strip solution can be the salt of an imaging agent (e.g., Na{sub 4}HEDPA) and thus may, under the appropriate conditions, be injected directly into the human body. {sup 99m}TcO{sub 4}{sup {minus}} can also be concentrated from a dilute load solution of {sup 99}MoO{sub 4}{sup 2{minus}} in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with K{sub 2}CO{sub 3} assures that all {sup 99}MoO{sub 4}{sup 2{minus}} is removed from the column and this is confirmed by a rapid drop in {sup 99}Mo activity by the fourth free column volume (fcv) of rinse. The {sup 99m}TcO{sub 4}{sup {minus}} is then eluted with water. This chromatographic separation affords 94% of the {sup 99m}TcO{sub 4}{sup {minus}} activity in 5 fcv, with the y spectrum showing less than 2 {times} 10{sup {minus}4} of the original {sup 99}Mo activity.

Rogers, R.D.; Bond, A.H.; Zhang, Jianhua [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Chemistry; Horwitz, P. [Argonne National Lab., IL (United States)

1995-12-31

396

New high T(c) multiferroics KBiFe?O? with narrow band gap and promising photovoltaic effect.  

PubMed

Intrinsic polarization of ferroelectrics (FE) helps separate photon-generated charge carriers thus enhances photovoltaic effects. However, traditional FE with transition-metal cations (M) of d? electron in MO? network typically has a band gap (E(g)) exceeding 3.0?eV. Although a smaller E(g) (2.6?eV) can be obtained in multiferroic BiFeO?, the value is still too high for optimal solar energy applications. Computational "materials genome" searches have predicted several exotic MO? FE with E(g) < 2.0?eV, all thus far unconfirmed because of synthesis difficulties. Here we report a new FE compound with MO? tetrahedral network, KBiFe?O?, which features narrow E(g) (1.6?eV), high Curie temperature (T(c) ~ 780?K) and robust magnetic and photoelectric activities. The high photovoltage (8.8?V) and photocurrent density (15??A/cm²) were obtained, which is comparable to the reported BiFeO?. This finding may open a new avenue to discovering and designing optimal FE compounds for solar energy applications. PMID:23405279

Zhang, Ganghua; Wu, Hui; Li, Guobao; Huang, Qingzhen; Yang, Chongyin; Huang, Fuqiang; Liao, Fuhui; Lin, Jianhua

2013-01-01

397

Vortex dynamics in ferromagnetic / high Tc superconducting heterostructures  

NASA Astrophysics Data System (ADS)

In this work we explore the influence of the ferromagnetic landscape generated by magnetic phase separation in manganites on the vortex pinning of HTS/FM heterostructures. We have grown Gd2/3Ca1/3MnO3 (GCMO), Y2/3Ca1/3MnO3 (YCMO) and YBCO films, as well as GCMO/YBCO and YCMO/YBCO bilayers by Pulsed Laser Deposition. GCMO is a ferrimagnetic material with Curie temperature of ˜ 80 K and a compensation temperature of 15 K, whereas YCMO is ferromagnetic with Curie temperature ˜ 80 K. In both materials the saturation magnetization is smaller than the value expected from ferrimagnetic and ferromagnetic order, suggesting phase separation with small ferromagnetic domains. The magnetic domain size as a function of temperature for the magnetic films was investigated using magnetic force microscopy (MFM). We will present a comparison of the vortex pinning and dynamics in the YBCO single layers and the GCMO/YBCO and YCMO/YBCO bilayers that allows us to identify the temperature and field regimes where magnetic pinning is effective.

Haberkorn, N.; Kim, J.; Miura, M.; Maiorov, B.; Dowden, P.; Civale, L.

2011-03-01

398

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

399

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

SciTech Connect

The reduction of Tc(VII) by ascorbic acid in HCl solution proceeds according to the equation 2TcO/sub 4//sup -/ + 3C/sub 6/H/sub 8/O/sub 6/ + 10HCl = 2TcCl/sub 5//sup -/ + 3C/sub 6/H/sub 6/O/sub 6/ + 8H/sub 2/O. The reaction is characterized by an induction period, after the conclusion of which its rate is equal to -d(Tc(VII))/dt = k(Tc(VII)) x (C/sub 6/H/sub 8/O/sub 6/) (H/sup +/)/sup 1.6/, where k = 0.898 + 0.064 liter/sup 2.6//mole/sup 2.6./min at 25/sup 0/C and ..mu.. = 2. The reaction mechanism includes a slow step of interaction of TcO/sub 3//sup +/ ions with C/sub 6/H/sub 8/O/sub 6/ molecules and ascorbate complexes of Tc(IV). The full kinetic equation describing the course of the reaction, including the induction period, is obtained.

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

1988-03-01

400

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

Breniere, Simone Frederique; Aliaga, Claudia; Waleckx, Etienne; Buitrago, Rosio; Salas, Renata; Barnabe, Christian; Tibayrenc, Michel; Noireau, Francois

2012-01-01

401

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, Cicero B.; Canepa, Gaspar E.; Bertotti, Santiago; Durante, Ignacio M.; Azambuja, Patricia; Buscaglia, Carlos A.

2013-01-01

402

Molecular Imaging of Mesothelioma with 99mTc-ECG and 68Ga-ECG  

PubMed Central

We have developed ethylenedicysteine-glucosamine (ECG) as an alternative to 18F-fluoro-2-deoxy-D-glucose (18F-FDG) for cancer imaging. ECG localizes in the nuclear components of cells via the hexosamine biosynthetic pathway. This study was to evaluate the feasibility of imaging mesothelioma with 99mTc-ECG and 68Ga-ECG. ECG was synthesized from thiazolidine-4-carboxylic acid and 1,3,4,6-tetra-O-acetyl-2-amino-D-glucopyranose, followed by reduction in sodium and liquid ammonia to yield ECG (52%). ECG was chelated with 99mTc/tin (II) and 68Ga/69Ga chloride for in vitro and in vivo studies in mesothelioma. The highest tumor uptake of 99mTc-ECG is 0.47 at 30?min post injection, and declined to 0.08 at 240?min post injection. Tumor uptake (%ID/g), tumor/lung, tumor/blood, and tumor/muscle count density ratios for 99mTc-ECG (30–240?min) were 0.47 ± 0.06 to 0.08 ± 0.01; 0.71 ± 0.07 to 0.85 ± 0.04; 0.47 ± 0.03 to 0.51 ± 0.01, and 3.49 ± 0.24 to 5.06 ± 0.25; for 68Ga-ECG (15–60?min) were 0.70 ± 0.06 to 0.92 ± 0.08; 0.64 ± 0.05 to 1.15 ± 0.08; 0.42 ± 0.03 to 0.67 ± 0.07, and 3.84 ± 0.52 to 7.00 ± 1.42; for 18F-FDG (30–180?min) were 1.86 ± 0.22 to 1.38 ± 0.35; 3.18 ± 0.44 to 2.92 ± 0.34, 4.19 ± 0.44 to 19.41 ± 2.05 and 5.75 ± 2.55 to 3.33 ± 0.65, respectively. Tumor could be clearly visualized with 99mTc-ECG and 68Ga-ECG in mesothelioma-bearing rats. 99mTc-ECG and 68Ga-ECG showed increased uptake in mesothelioma, suggesting they may be useful in diagnosing mesothelioma and also monitoring therapeutic response. PMID:22645409

Zhang, Yin-Han; Bryant, Jerry; Kong, Fan-Lin; Yu, Dong-Fang; Mendez, Richard; Edmund Kim, E.; Yang, David J.

2012-01-01