To see the other types of publications on this topic, follow the link: Radiochemical.
Dissertations / Theses on the topic 'Radiochemical'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Radiochemical.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Jia, Di. "A radon chamber and its role in a radon survey /." [Hong Kong : University of Hong Kong], 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13385379.
Full text
2
Aoki, Toru. "APPLICATIONS OF RADIOCHEMICAL ANALYSIS IN ENVIRONMENTAL SCIENCE." Kyoto University, 1999. http://hdl.handle.net/2433/181406.
Full text
3
Tann, Julie. "ESR studies of liquid phase radiolysis using spin traps." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328546.
Full text
4
Sedaghat, Mahbod. "A study on radiochemical errors in polymer gel dosimeters." Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6252.
Full textAbstract:
À ce jour, les seul dosimètres purement tridimensionnels (3D) sont basés sur la détection d’une propriété physique résultant d’une série de réactions chimiques radio-induites dans un volume de gel ou de plastique. Les études initiales ont généré beaucoup d’enthousiasme mais ces dosimètres 3D ne sont pas parvenus à une utilisation répandue dans les départements de radio-oncologie pour l’assurance-qualité 3D et la vérification de traitements complexes de radiothérapie moderne. Le temps et la complexité de la préparation de ces dosimètres 3D ne sont pas les raisons principales qui empêchent leur déploiement clinique. Ce sont plutôt leurs performances et la reproductibilité des mesures qui doivent être améliorées. Les plus étudiés et les plus utilisés parmi les différents types de dosimètres 3D sont les dosimètres à gels de polymère. De nombreuses compositions chimiques ont été proposées et testées pour la dosimétrie à gels de polymère. L’utilisation d’un antioxydant s’est révélée une découverte majeure dans le domaine puisque l’oxygène interfère avec le mécanisme de réponse des gels. Pourtant, un nombre croissant d’erreurs inexpliquées ont été rapportées dans les écrits et ont soulevé un doute sur la reproductibilité et la justesse des doses déterminées avec ces gels. Cette thèse a été entreprise pour étudier les sources radiochimiques d’erreurs dans les dosimètres à gels de polymère. Il était admis dans les écrits que l’utilisation d’un antioxydant permettait de contoumer tous les effets non-désirés de l’oxygène. Cette thèse démontre que cela était faux. Une méthodologie a été développée pour isoler l’effet de l’oxygène dans un gel de polymère contenant ou non un antioxydant. Les résultats ont révélé que la présence conjointe d’oxygène et d’antioxydant modifie la réponse du dosimètre. Indépendamment de la composition du dosimètre et de l’antioxydant, cet effet peut induire des erreurs dosimétriques significatives dans des mesures simples et dont les origines étaient difficilement appréciables en ignorant l’effet de l'oxygène et de l’antioxydant. Nos résultats nous permettent de postuler les réactions dominantes des antioxydants étudiés et leur devenir chimique au sein d’un gel de polymère sous irradiation. Puisque l’effet de l’oxygène et de l’antioxydant était négligé, plusieurs autres facteurs physico-chimiques faisaient l’objet d’hypothèse pour expliquer les erreurs observées. Ces facteurs incluent la compression des gels et des variations de propagation et de terminaison de la polymérisation reliées à la chaleur générée pendant la polymérisation. Des études détaillées de ces effets nous permettent de refuter ces hypothèses. Nos résultats nous permettent d’analyser, de catégoriser et de proposer des explications sur l’origine des erreurs dosimétriques recensées dans les écrits. Finalement, l’effet d’un antioxydant en particulier, le chlorure de tetrakis-(hydroxyméthyle) phosphonium (THPC), a été étudié en relation avec la structure du polymère formé dans un gel de polymère basé sur l’acrylamide. Le THPC est l’antioxydant le plus utilisé dans les différents dosimètres à gels de polymère. La spectroscopie FT-Raman et la microscopie électronique ont révélé que le THPC réagit avec les monomères pendant la polymérisation. Notre interprétation suggère un rôle important du THPC dans les variations de réponse à la dose dans les gels de polymère. La conclusion générale de cette thèse est que l’élimination chimique de l'oxygène par un antioxydant facilite grandement la préparation des dosimètres mais leur performance en est grandement altérée en comparaison avec des préparations dites anoxiques. L’oxygène demeure une source majeure d’erreur dans les dosimètres à gels de polymère.
5
Scheres, Hubertus Maria Elisabeth. "Immunocytochemical and radiochemical determination of steroid receptors in breast cancer." Maastricht : Maastricht : Rijksuniversiteit Limburg ; University Library, Maastricht University [Host], 1989. http://arno.unimaas.nl/show.cgi?fid=5469.
Full text
6
Simmonds, Isaac D. "Radiochemical and Analytical Methods of Analysis of Radiological Dispersal Devices." Thesis, University of Missouri - Columbia, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13877171.
Full textAbstract:
<p> The events on September 11<sup>th</sup> 2001 and subsequent attacks in America and around the world have brought a renewed interest in the nation’s security including the concern over the use of a nuclear or a radiological dispersal device (RDD). Research utilizing NAA and ICP-MS has been done in two separate projects in order to help address some of these concerns. A research assistantship from Savannah River National Laboratory was granted in order to identify the impurities and isotope ratios of <sup> 192</sup>Ir sources (chapters 2-4). An electrochemical dissolution method of the iridium was developed and used for sample preparation for ICP-MS analysis. ICP-MS analysis was then used to identify and quantify impurities and isotope ratios in iridium from various sources. The second research project has developed a series of lanthanide phosphate based nanoparticles for use as tagging and tracking agents (chapters 5-7). The composition of the nanoparticles were varied to provide a unique signature that can be rapidly and precisely measured in the field via neutron activation analysis. The nanoparticles could be used as a real-time in the field method for tracking and identifying materials such as explosives in a post detonation scenario.</p><p>
7
Cavaliere, Alessandra. "Radiochemical synthesis of 18F-radiolabelled ProTides for Positron Emission Tomography." Thesis, Cardiff University, 2018. http://orca.cf.ac.uk/109710/.
Full textAbstract:
Positron Emission Tomography (PET) is a highly sensitive imaging technique used in cancer diagnosis, treatment planning and monitoring of therapy response. [18F] is an optimal PET label considering its half-life (110 min) and imaging resolution. One of the major challenges in [18F]-PET research is the installation of the weakly nucleophilic [18F]fluoride into a precursor molecule to access novel [18F]-tracers. Fluorinated nucleosides represent an important class of diagnostic probes for PET imaging as well as anticancer and antiviral therapeutic agents. However drug resistance still represents a major problem. The ProTide approach is a strategy to synthesize prodrugs of the nucleoside monophosphates which overcome their main resistance mechanisms. The challenge of the project is the [18F]-fluorination (hot fluorination) of ProTides which may be potential new PET imaging agents and could thus represent a model system to visualize pharmaceutical effects and bioactivation of ProTides directly in vivo. The pro-nucleotide multistep synthetic chemistry has been applied for the synthesis of ProTides. The [18F]-radiolabeling of the precursor molecules was performed in an Eckert & Ziegler automated synthetic Modular Lab placed into a shielded hot cell. The radioactive reaction mixtures were analyzed by radio HPLC, and radio TLC. Two different approaches have been followed to access two chemically distinct radiolabelled ProTides. The 3’-[18F]FLT ProTide was synthesised via a late stage [18F]fluorination of ad hoc synthesised precursor molecules (Figure 1). Figure 1: Radiochemical synthesis of 18F- FLT ProTides The 2’-[18F]FIAU ProTide was synthesised via an early stage [18F]fluorination approach (Figure 2). Figure 2: Radiochemical synthesis of 18F-FIAU ProTides These radiolabelled probes could provide evidence for the in vivo behaviour of this class of compounds by answering key questions about their metabolism and uptake directly. In addition, the project focused on the synthesis of two novel classes of non-radiolabelled fluorinated ProTides. A series of uridine based ProTides (FIAU ProTides) and a series of coumarin based FLT ProTides have been synthesised and evaluated for their antiviral activity and fluorescent properties respectively.
8
Curley, R. K. "Radiochemical neutron activation analysis of copper and molybdenum in human tissues." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233790.
Full text
9
Parker, Mark John. "Kinetic modelling studies of amine-epoxide cure reactions using radiochemical tracers." Thesis, University of Surrey, 1992. http://epubs.surrey.ac.uk/843849/.
Full textAbstract:
The process of curing epoxides with amines has been for many years a route to obtain many useful materials, from everyday substances such as adhesives right through to thermoset resins used in advanced composite manufacture. This work will try to highlight how a combination of chemical and numerical techniques come together to aid the further understanding, of what is an extremely complex reaction. Chapter 1(a) is a general review of epoxy resin curing chemistry, paying particular attention as to how our understanding of the process has developed over several decades, and highlights the various techniques used to study the reaction. Chapter 1(b) describes the experimental approach taken in this work, namely that of using model reactants in combination with radiochemical techniques in order to gain kinetic information about cure reactions. In Chapter 2 the development of the various kinetic models is discussed. It is first described how, and on what basis, various aspects of the cure chemistry are incorporated into the model. One then goes on to describe the numerical analysis applied to the rate equations, and how this is incorporated within the model. The results of the two major aspects of the work are divided into two distinct areas. The first (Chapter 3) deals with the modelling of those reactions using a low initial concentration of primary amine (usually < 0.6M). These systems are devoid of many of the complicating features of cure reactions, and are shown to be modelled to a high degree of accuracy. In essence they are ideal systems, and ones which the initial model (KINET31) used in this study is able to describe. Chapter 3 also describes some studies carried using aromatic diamines, and the modelling performed of these reactions. Chapter 4 on the other hand deals with those reactions which used high initial amine concentrations. By contrast the standard of modelling shown here with KINET31 was much poorer. It is then described how various physical aspects of the cure reaction are investigated in an attempt to highlight the model's inadequacy. It is eventually shown how H-bonding of species, and the formation of pre-complexes, can play a very significant role in cure reactions. When the model is adapted to take these interactions into account a significant improvement is noted (KINET31H). Finally Chapter 5 deals with another interesting aspect of cure reactions, namely that of accelerators. With the model now taking into account the formation of the most are. significant pre-complexes, the reactivities of various -OH type accelerators are investigated.
10
Rossouw, Daniel Du Toit. "Synthesis and radiochemical stability evaluation of radiopharmaceutical compounds containing radioiodinated prosthetic groups." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50113.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2004.<br>ENGLISH ABSTRACT: A study was undertaken to investigate the radiochemical stability of the βiodoethoxyl moiety,
a relatively novel prosthetic group employed in radiopharmaceutical chemistry, in which an
oxygen atom in a β-position relative to the radioiodine atom has a stabilising effect on the
aliphatic carbon-iodine bond. The investigation was started as a pilot study by synthesising
various model compounds containing a β-radioiodoethoxyl moiety, as well as two reference
compounds lacking such a moiety. The purpose was to determine the influence of various
groups in the vicinity of the β-oxygen atom on the stability of the abovementioned moiety.
Radiochemical stability tests were carried out in vitro at 37°C in human blood serum. The
results confirmed the superior stability of such a moiety compared to that of the reference
compounds and also showed that the branching of such an aliphatic unit resulted in a
considerable improvement in its stability, especially over a longer period.
The investigation was extended to the synthesis of other compounds containing a few selected
β-iodoethoxyl moieties that showed improved stability in the pilot study work. Reference
compounds containing the classical iodovinyl unit, as well as those lacking a stabilising β-
oxygen atom, were also prepared. The carrier molecules used in this part of the work was a
benzamide containing a phenolic oxygen atom which acted as the β-oxygen atom, as well as
two heterocyclic amines, benzotriazole and 2-methyl-5-nitroimidazole, in which the β-
iodoethoxyl moiety was linked to a secondary nitrogen atom. Various suitable alkylating agents
were prepared, chemically linked to the carrier molecules, the resulting intermediate
compounds converted into tosylate or triflate iodination precursors and labelled with
radioiodine by means of iodide-for-tosylate/triflate exchange. In vitro stability tests of these
compounds showed similar trends to those obtained with the model compounds. Moreover, the
stability of the stabilised β-iodoethoxyl moiety compared favourably with that of the iodovinyl
unit, especially when incorporated into a heterocyclic amine. The results of this study have shown that some of the radioiodinated compounds synthesized in this work, especially the
nitroimidazole derivatives, have the potential to be considered as novel radiopharmaceuticals.<br>AFRIKAANSE OPSOMMING: 'n Studie is onderneem om die radiochemiese stabiliteit van die β-jodium-etoksi-eenheid te
ondersoek. Dié eenheid is 'n relatief nuwe prostetiese groep wat in radiofarmaseutiese chemie
gebruik word. Die suurstofatoom wat in 'n β-posisie relatief tot die radiojodiumatoom
voorkom, oefen 'n stabiliserende invloed op die alifatiese koolstof-jodiumbinding uit. Die
ondersoek het met 'n loodsstudie begin deur verskillende modelverbindings te sintetiseer wat 'n
β-radiojodium-etoksi-eenheid bevat, asook twee verwysingsverbindings waarin so 'n eenheid
ontbreek. Die doel hiermee was om die invloed van verskillende groepe, wat in die omgewing
van die β-suurstofatoom voorkom, op die stabiliteit van die eenheid te bepaal. Radiochemiese
stabiliteitstoetse is uitgevoer deur middel van inkubering in menslike bloedserum by 37°C. Die
resultate het die groter stabiliteit van so 'n eenheid in vergelyking met dié van die
verwysingsverbindings aangetoon, en het ook uitgewys dat vertakking van so 'n alifatiese
eenheid 'n aansienlike verbetering in die stabiliteit tot gevolg gehad het, veraloor 'n langer
periode.
Die ondersoek is vervolgens uitgebrei deur verdere verbindings te sintetiseer wat beskik oor
bepaalde uitgesoekte β-jodium-etoksi-eenhede, wat verbeterde stabiliteit in die loodsstudie
getoon het. Verwysingsverbindings wat die klassieke jodiumvinieleenheid bevat het, sowel as
dié waarin 'n stabiliserende β-suurstofatoom ontbreek het, is ook berei. Die draermolekules
wat in hierdie deel van die studie gebruik is, was 'n bensamied met 'n fenoliese suurstofatoom
wat as die β-suurstofatoom gedien het, sowel as twee heterosikliese amiene, bensotriasool en 2-
metiel-5-nitroimidasool, waarin die β-jodium-etoksi-eenheid aan 'n sekondêre stikstofatoom
geheg is. Verskillende geskikte alkileermiddels is berei, aan die draermolekules geheg, die
tussenprodukte omskep in tosilate of triflate en met radiojodium gemerk deur middel van
jodium-vir-tosilaatltriflaat-uitruiling. Stabiliteitstoetse van hierdie verbindings in bloedserum
het soortgelyke tendense as dié van die aanvanklike modelverbindings getoon. Daarbenewens
het die stabiliteit van die gestabiliseerde β-jodium-etoksi-eenheid gunstig vergelyk met dié van die jodiumviniel-eenheid, veral wanneer dit deel gevorm het van 'n heterosikliese amien. Die
resultate van die studie het getoon dat sommige van die radiogejodeerde verbindings wat berei
is, veral die nitroimidasoolderivate, die potensiaal het om as nuwe radiofarmaseutiese
verbindings gebruik te kan word.
11
Millar, Alistair Mackay. "Radiochemical purity of technetium-99m radiopharmaceuticals : measurement by high performance liquid chromatography." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/20018.
Full textAbstract:
High performance liquid chromatography (HPLC) has been reported as a means of demonstrating the multicomponent nature of <SUP>99m</SUP>Tc radiopharmaceuticals. HPLC has not, however, been widely reported as a satisfactory technique for measuring the radiochemical purity (RCP) of <SUP>99m</SUP>Tc radiopharmaceuticals. Inadequate techniques based on thin-layer and paper chromatography are in widespread use for this purpose. The aim of the work described in this thesis was therefore to carry out a scientific investigation to establish if quantitative HPLC is a technique that can be used to measure the RCP of <SUP>00m</SUP>Tc radiopharmaceuticals. An on-line radiation detector was developed and evaluated. This was constructed from a length of column outlet tubing positioned inside the well or across the face of a sodium iodide crystal scintillation detector. The different configurations of tubing and crystal were used to create different sensitivities of detection. Chromatograms were recorded with either a counter-ratemeter/printer system or a computer-based multichannel analyser. At 6,000 counts per second, the highest count-rate encountered in the course of the work, the loss due to dead-time in the multichannel analyser was satisfactorily low at 0.5%. For successful measurement of RCP, none of the radiolabelled species in a radiopharmaceutical must be retained on the HPLC column and thereby escape detection. A technique for measuring recovery from the column was therefore developed. This involved injecting the sample onto the column with a loop-valve injector, collecting the eluate and measuring the count-rate from it relative to the count-rate from an accurately pipetted sample of the radiopharmaceutical.
12
Weber, Daniel. "Comparison of autoradiographic and radiochemical estimation of DNA synthesis in gastric mucosa /." [S.l : s.n.], 1986. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Full text
13
Higginson, Matthew. "Rapid radiochemical separations of americium from actinides, mixed fission products and matrix elements." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/rapid-radiochemical-separations-of-americium-from-actinides-mixed-fission-products-and-matrix-elements(58eb5847-48d7-49dc-80d4-a53a2e4bab56).html.
Full textAbstract:
In analysis of complex nuclear forensic matrices containing lanthanides, actinides and matrix elements, rapid selective extraction of Am/Cm for quantification is challenging due to the difficult separation of Am/Cm from lanthanides. This project attempts to develop novel separation processes for Am/Cm separation utilising liquid-liquid extraction and extraction chromatography based on soft N-donor triazine extractants. Selective extractants were identified and synthesized and a liquid-liquid separation procedure was developed. Of these ligands, CyMe4-BTPhen, CyMe4-BTBP, CA-BTP and CA-BTPhen were compared for application to complex matrices. The developed process allows for purification and quantification of Am and Cm (recoveries 80–100%) and other major actinides in < 2 days without the use of multiple columns or thiocyanate, yielding a full data set. The process developed was shown to be unaffected by Ca/Fe/Al (10 mg mL-1) and thus requires little pre-treatment of samples. Due to limited availability of media for separation of americium using EC, we synthesized and tested a novel covalently-linked EC resin, utilising a triazine soft N-donor (Me4BTPhen) extractant for americium extraction. The resin was generated by conjugation of a Me4BTPhen derivative with poly(vinylbenzyl) chloride to generate PVB-Me4BTPhen. PVB-Me4BTPhen was shown to extract americium from a complex matrix simulating nuclear forensic samples, and containing lanthanides, actinides and matrix elements with high Am (III) recovery ( > 90%) and low extraction of other elements, and provides an alternative separation process for Am (III) extraction. Adsorption was also investigated as an alternative, more flexible approach to resin preparation. BTBP/BTPhen Am selective triazine ligands were adsorbed onto Amberlite XAD-7, then characterised and tested for Am/Eu selectivity, complexation kinetics and polymer loading. These polymers were tested with complex matrices in conjunction with AG1-X8 anion exchange chromatography to achieve a complete isotope separation and quantification method. From these results, the resin capacity factor (KD) as a function of HNO3 concentration was calculated, allowing potential separation methods to be designed. Selective americium extractants from the BTPhen ligand family have been identified through this work, and we also report a study of functionalisation of BTPhen ligands to help design new selective Am extractants by determining the effects on solubilities and americium extraction capabilities of variations in substituents. The data obtained show trends that could assist in future ligand design.
14
Lanfranchi, Jean-Côme. "Development of a new composite cryogenic detection concept for a radiochemical solar neutrino experiment." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=979098238.
Full text
15
Mahmoud, Ashraf M. M. "Radioimmunoassay and radiochemical procedure determination of cutaneous uptake and metabolism of sex steroid hormones." [S.l.] : [s.n.], 2005. http://www.diss.fu-berlin.de/2005/131/index.html.
Full text
16
Shabani, Amin. "Thermal and radiochemical of neat and ATH filled EPDM : establishment of structure/properties relationships." Phd thesis, Paris, ENSAM, 2013. http://pastel.archives-ouvertes.fr/pastel-00941289.
Full textAbstract:
EPDM elastomer is widely used as the insulation of low to medium voltage electrical cables used in power plants, for which the life-time prediction has been hampered by the lack of knowledge on structure/mechanical properties, and the nonexistence of pertinent criteria of structural failure. In an attempt to fill this gap, three EPDM matrices filled with 0, 33 and 100 phr of pristine and surface treated ATH were crosslinked by dicumyl peroxide at 170°C and, subsequently, aged thermally at 90,110 and 130°C, and radiochemically under 0.1, 1 and 10 kGy.h-1, in air. A multi-scale approach was employed to analyze the oxidation of EPDM at molecular scale, and to determine its consequences at macromolecular and macroscopic scales by using several complementary characterization techniques: FTIR spectrophotometry, differential calorimetry, rheometry in melt state, swelling test, uniaxial tensile testing, etc. The structure/properties relationships established in this study are capable to explain, in particular, the alteration of elastic and fracture properties of the EPDM matrices due to chain scissions, and the reinforcement of the filler/matrix interphases induced by the specific conditions of oxidation.
17
Pyle, David Mark. "Geological and radiochemical studies of young volcanoes : Santorini, Greece and Ol Doinyo Lengai, Tanzania." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357874.
Full text
18
Chua, Ching Ching. "The application of soluble supports in the radiochemical asymmetric total synthesis of tea flavanols." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/837/.
Full textAbstract:
Flavan-3-ols such as (—)-epicatechin and (+)-catechin are found in significant concentrations in red wine, green and black teas and cocoa. The radiolabelling of flavan-3-ols for feeding studies would require a short high-yielding route from the point of introduction of the label. (E)-1,3-Diarylpropenes had been key intermediates in previous syntheses of flavan-3-ols and so the modified Julia alkenation reaction between a labelled aryl aldehyde and a 2-(2'-arylethylsulfonyl)benzothiazole was proposed as the key step in the preparation of radiolabelled (E)-1,3-diarylpropene. A low molecular weight poly(ethyleneglycol)-monomethyl ether (MPEG, average MW 550) support would be used to improve the efficiency of isolating radiolabelled product after each reaction. The light MPEG support was attached to the starting aryl bromide by protecting the phenolic hydroxyl group with a new light MPEG α,α’-dioxyxylyl protecting group, introduced by reaction with light MPEG-supported benzylic bromide, to give supported aryl bromide. The aryl bromide was reacted with copper (I) cyanide to give MPEG-supported nitrile. In theory, 14C-labelled cyanide could be used in this step. Reduction and hydrolysis gave the aldehyde. Throughout the sequence MPEG solid-phase extraction (M-SPE) was used to assist purification. Several approaches to the synthesis of 2-(2'-arylethylsufonyl)benzothiazole were then investigated using a variety of model 2-arylethyl sulfones. The novel addition of phenylcopper to phenyl vinyl sulfone gave 2-phenethyl phenyl sulfone in good yield, but the reaction was less effective for sterically hindered arylcoppers and unsuccessful for the preparation of 2-(2'-arylethylsufonyl)benzothiazoles. Alkylcopper reagents were also suitable substrates for this novel coupling. Heck reaction between aryl iodide and phenyl vinyl sulfone, and reduction of the resulting alkene gave 2-arylethyl phenyl sulfone but the Heck reaction failed with benzothiazolyl analogues. Lithiated 2-(methylthio)benzothiazole reacted with aryl aldehydes to give β-hydroxy sulfides, but reduction to 2-arylethyl derivatives failed, even after oxidation of the sulfide to the sulfone or elimination to give a vinyl sulfide or sulfone. The same problem was encountered when lithiated 2-(trimethylsilylmethylthio)benzothiazole was use to make vinyl sulfides directly. However, alkylation of lithiated 2-(methylthio)benzothiazole with benzyl bromide gave 2-(2'-phenylethylsufonyl)benzothiazole in good yield. Unfortunately, the reaction could not be used to prepare phloroglucinol-derived benzothiazole. Finally, the benzothiazoles underwent modified-Julia alkenation reaction with electron-rich benzaldehydes to give (E)-1,3-diarylpropenes in high yield.
19
Zhang, Michael Ming-Ruo. "Measurement and interpretation of chemical and radiochemical data from PWR in-pile loop runs." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13855.
Full text
20
Knight, Andrew William. "Radiochemical analysis of protactinium speciation: applications in nuclear forensics, nuclear energy, and environmental radiochemistry." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2233.
Full textAbstract:
Protactinium (Pa) is an actinide with chemical properties that are unique among the actinide elements. While the properties of other actinides are to a large extent understood, much of the chemistry of Pa remains a mystery. This thesis aims to illuminate new understanding of Pa chemistry through behavioral analysis using analytical techniques including liquid-liquid extraction (LL); extraction chromatography (ExC); and spectroscopic studies.
Applications of radioanalytical chemistry and Pa: Through the research presented in this dissertation, we have developed a new way to separate uranium (U), thorium (Th), and Pa from complex environmental samples. The approach has been demonstrated for U-series dating of materials by alpha spectrometry. The method can be applied to geochronology, as well as to nuclear-forensic analysis of uranium-containing materials. In studies presented here, samples from a Paleolithic lake (Lake Bonneville, Utah USA) were analyzed for the radioactivity concentration of 230Th, 231Pa, 234U, 235U, and 238U by isotope dilution alpha spectrometry. Radioactivities were used to estimate of the time period of formation of the deposit from which the samples were collected. Ages were determined from the isotopics ratios; i.e., 231Pa/235U (40 ka); and 230Th/238U (39.5 ka) we found to be concordant with radiocarbon-14 dates (37 ka) obtained by collaborators at Brigham Young University. These studies inspired the development of a novel ExC resin to facilitate preparation of highly pure tracer isotope (233Pa) from a neptunium-237 (237Np) source. The material used for this development comprised 1-octanol adsorbed to a semi-porous resin material. The new approach greatly improved the yield and purity of 233Pa used for these chronometric analyses
Developing an understanding of the chemistry of Pa at trace concentrations: The new-improved analytical described above led to the hypothesis that analytical separations approaches could be used to develop a more detailed understanding of Pa chemistry. Toward this goal, experiments were conducted to understand how the extraction of Pa is impacted by solution acidity [H+], anion concentration [A-; Cl-, NO3-], and extractant concentration ([2,6-dimethyl-4-heptanol, DIBC]). A full-factorial experimental design was employed to create a model that would allow for predictions in Pa behavior, as well as describe the nature of the observations. This model generated a multivariate equation that relates the distribution coefficient ([Pa] organic phase/ [Pa] aqueous phase) to each of the parameters ([H+], [A-], and [DIBC]). Further studies expanded to other alcohols (ROH) used as extractants (1-octanol, (2,6)-dimthyl-4-heptanol, and 2-ethyl-hexanol); and the results were analyzed using the slope analysis and comparative extraction studies using the model and compared to other actinide elements (Th, U, Np, americium (Am)) by both LL and ExC systems. These experiments revealed unique chemical behavior of Pa with respect to the other actinides. For example, it was found that Pa was the only actinide element to be extracted into the organic phase under acidic conditions (HCl and HNO3). Slope analysis experiments elucidated the stoichiometric identity of Pa species, with respect to the anion and extractant. Future studies will aim to identify the oxygen stoichiometry and species by X-ray absorption techniques.
Investigations of the organic phase: In the final sections of this thesis, experiments are presented that are intended to determine if aggregation plays a key role in the extraction of Pa in systems containing 1-octanol and 2-ethyl-hexanol. This work is done in the absence of metal ions to control the dynamics of the organic phase, and are analyzed by tensiometry and Karl Fisher titrations with small angle X-ray scattering and molecular dynamic simulations. A key novel finding of these studies in that ROH molecules arrange in nanoscale aggregates that decrease the interfacial tension between the phases and extract a significant amount of water into the aggregates stabilized by a network of H-bonding. These studies lead to the hypothesis for future studies that Pa extraction is likely facilitated by solvation into the organic phase via ROH aggregates.
The sum of the findings and observations of this dissertation provide insight into the chemical nature of Pa: (1) Novel extraction methods to obtain radiochemically pure fractions show that Pa can be efficiently extracted and separated from complex matrices to aid in chronometric analysis for geochronology or nuclear forensics; (2) Statistical modeling to develop a better understanding of the main effects of solvent extraction parameters; (3) Equilibrium analysis to improve our understanding of chemistry of Pa and how it is unique to the actinides; (4) Aggregation analysis to demonstrate a solvent centric understanding of extraction studies, these results lead to future experiments to investigate how organic phase aggregation can influence solvent extraction selectivity.
21
MONTEIRO, ELISIANE de G. "Estudo comparativo entre metodologias de cromatografia planar para controle radioquímico de radiofármacos de tecnécio-99m." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10162.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:35:28Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:05:34Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
22
Furtado, Linda Michelle. "Interfacial oligonucleotide chemistry studied by an on-line biosensor, radiochemical labelling and nucleic acid microarrays." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ63600.pdf.
Full text
23
Hagstrom, Kate. "Particle dynamics and shelf-basin interactions in the western Arctic Ocean investigated using radiochemical tracers /." View online ; access limited to URI, 2006. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/fullcit/3239908.
Full text
24
Graves, S., S. Goel, F. Chen, et al. "Production and novel radiochemical separation of 194Au from Pt for use in multi-modality nanoparticles." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-166428.
Full textAbstract:
Introduction
Gold nanoparticles (AuNPs) have demonstrated their incredible versatility in applications such as in vitro and in vivo imaging, cancer therapy, and drug delivery.[1-3] These AuNPs come in many shapes including nanospheres, nanorods, nanoshells, and nanocages. Their versatility stems from the ability to construct or label a single AuNP with many functions. Many types of AuNPs are inherently flourescent, allowing for ex vivo utilization as well as small animal fluorescence imaging.[4] High atomic number and physical density allow for the possibility of using AuNPs as computed tomography (CT) contrast agents, especially in dual energy applications.[5]
Some attempts have been made to bring AuNPs into the realm of nuclear medicine, mostly involving the extrinsic labeling of chelated radio-metals. Although these strategies have brought some success, an intrinsic labeling strategy could reduce concerns of in vivo instability, and changes in pharmacokinetic behavior.[6] Intrinsic radiolabeling strategies involve synthesizing the nanoparticles in the presence of a gold radioisotope, which is thereby structurally incorporated. The isotope of choice for this technique has typically been 198Au (t½ = 2.7 d, Eγ = 411.8 keV) as it is reactor produced and commercially available. However with such a high energy gamma ray, SPECT aquisition is far from optimal.
Motivated by the shortcomings of previous intrinsic labeling techniques, we have sought to develop 194Au (t½ = 1.48 d, β+ = 1.73 %) as a potential PET isotope for labeling AuNPs. Although this nuclide has a weak positron branching ratio, it also has prominent gamma ray energies of 328 and 294 keV which are closer to the optimal SPECT energy window, allowing for the ability to image with both PET and SPECT.
Material and Methods
194Au was produced by natPt(p,x) using 16 MeV protons. Target construction consisted of a water jet cooled platinum disc.
Following irradiation, targets were etched by fresh concentrated aqua regia at 80 °C for four hours. The resulting solution was diluted by a factor of four and loaded onto a 50 mg UTEVA (Eichrom extraction resin) column equilibrated by 1 M HNO3. The column was rinsed with 10 mL 1 M HNO3, and the product was eluted using concentrated HNO3 in less than 1 mL.
Results and Conclusion
End of bombardment (EOB) yield for 194Au was measured to be 0.134 mCi/μAh by high purity germanium analysis. The half life was measured to be 38.5 ± 2.8 hours, which agrees well with the true half life of 37.92 hours. In addition to the production of 194Au, the production of 190–193Au and 196Au was observed. Most notably, the EOB yield for 193Au (t½ = 17.7 h) was 0.189 mCi/μAh.
Target dissolution was slow and incomplete after four hours of etching. Alternative dissolution strategies i.e. electrolytic dissolution may be needed moving forward. The separation of 194Au from bulk Pt via the UTEVA extraction resin was robust and efficient, with an average separation efficiency of 96 %. An extensive literature review revealed no other Au/Pt separation from solutions containing aqua regia. Future goals include synthesis of ultrasmall 194Au incorporated AuNPs using a facile thermal reduction method.PET, CT and fluorescence imaging will also be carried out in vivo to establish the multimodal capabilities of the intrinsically radio-labeled nanoplatforms.
To conclude, a novel separation technique has been developed to separate 194Au from Pt for use in intrinsically radiolabeled multi-modal AuNPs.
25
Al-Masri, Mohammad Said. "Radiochemical methods for the determination of some naturally occurring alpha emitters in environmental aqueous samples." Thesis, University of Salford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386455.
Full text
26
Garcia, Ramon. "Microwave-assisted decomposition of environmental samples, and the analysis of plutonium and radiostrontium." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/17233.
Full text
27
Jia, Di, and 賈地. "A radon chamber and its role in a radon survey." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31210818.
Full text
28
SAITO, ROBERTO T. "Determinacao de sup210 Pb e 210 Po em amostras marinhas e aerossois." reponame:Repositório Institucional do IPEN, 1996. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10480.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:40:57Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:01:22Z (GMT). No. of bitstreams: 1
04019.pdf: 3977762 bytes, checksum: 21b56916c7935f0514332dff16138d5b (MD5)<br>Dissertacao (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
29
Keinonen, Marja. "The isotopic composition of lead in man and the environment in Finland isotope ratios of lead as indicators of pollutant source /." Helsinki, Finland : University of Helsinki, Dept. of Radiochemistry, 1989. http://catalog.hathitrust.org/api/volumes/oclc/26521537.html.
Full text
30
Mosandl, Johannes. "Radiochemical and luminescence-based binding and functional assays for human histamine receptors using genetically engineered cells." kostenfrei, 2009. http://www.opus-bayern.de/uni-regensburg/volltexte/2009/1339/.
Full text
31
Jennewein, Marc. "Production, radiochemical separation and chemical coupling of radioactive arsenic isotopes to synthesize radiopharmaceuticals for molecular imaging." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975967606.
Full text
32
MARCONDES, MARCILIO A. "Influencia de aplicacoes de pesticidas na degradacao do herbicida (14)sup C-2,4-D em diferentes solos." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10845.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:44:38Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T13:57:34Z (GMT). No. of bitstreams: 1
07167.pdf: 3631679 bytes, checksum: cb7e0a99fa6e1637da6ee1088e5fb1f8 (MD5)<br>Dissertacao (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
33
Ashton, Linda. "Determination of ³⁶Cl and other long-lived radionuclides in decommissioning concrete wastes." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/14125.
Full textAbstract:
The decommissioning of nuclear power stations will lead to the production of a number of contaminated components. The materials produced will consist of process and structural wasteforms. Before this waste can be disposed it will be necessary to obtain a full inventory of those radionuclides contained in those wastes. This will be necessary to ensure that the waste is handled in a suitable manner and that full information is available so that reliable risk assessment can be carried out on the proposed disposal site. A number of radionuclides have been highlighted as significant in terms if their halflife, terrestrial mobility and predicted levels in decommissioning wastes. A selection of these radionuclides have been investigated, and methods developed for their determination in concrete. It was a requirement of this work that the methods developed were robust and that the minimum detectable amount was below that of the de minimis of O.4Bq g-1.
34
Monteiro, Elisiane de Godoy. "Estudo comparativo entre metodologias de cromatografia planar para controle radioquímico de radiofármacos de Tecnécio-99m." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-06032013-134516/.
Full textAbstract:
Os radiofármacos são substâncias que possuem radioisótopos em sua composição. Cerca de 95% dos procedimentos realizados em medicina nuclear faz o uso de radiofármacos com finalidade diagnóstica, sendo os reagentes liofilizados (RL) marcados com Tecnécio-99 meta estável (99mTc), obtido a partir de um gerador de 99Mo/99mTc, os mais utilizados. O controle de qualidade representa o conjunto de ensaios a serem realizados para certificar que o produto é adequado ao propósito. Um aspecto importante a ser avaliado nos radiofármacos de 99mTc é a pureza radioquímica (% PRq) para quantificação de pertecnetato livre (99mTcO4 -) e tecnécio coloidal (99mTcO2), principalmente por cromatografia em papel (CP), em camada delgada (CCD) e cromatografia líquida de alta eficiência (CLAE). O objetivo deste trabalho foi realizar a comparação das metodologias de controle radioquímico de RL marcados com 99mTc descritas nas farmacopéias americana (FA) e europeia (FE) com aquelas utilizadas no IPEN. O eluído de 99mTcO4 e os RL: DISIDA, DMSA, DTPA, EC, ECD, GHA, MIBI, MDP, PIRO, SAH e Sn Coloidal foram provenientes do IPEN-CNEN/SP. Foram utilizados os suportes cromatográficos TLC-celulose, TLC-SG,TLC-SG fase reversa, HPTLC-celulose e HPTLC-SG da Merck e ITLC-SG da Pall Corporation, W1MM, W3MM, W17M e W31ET da Whatman. A contagem da radioatividade foi feita em contador gama Perkin Elmer modelo Cobra D-5002. A marcação dos RL foi feita de modo a obter concentração radioativa de 55,0 MBq mL-1 (1,5 mCi mL-1). Foram determinadas as %99mTcO4 -, %99mTcO2 e % PRq até 4 horas de marcação. Dos 11 RL, apenas EC e GHA não possuem método de controle radioquímico na FA e FE. Na FA e/ou na FE, os métodos para DTPA, MDP, PIRO, SAH e Sn Coloidal utilizam ITLC-SG; no IPEN, este suporte cromatográfico é utilizado em DISIDA, EC, ECD, GHA, PIRO, MIBI e SAH. Devido à descontinuidade na fabricação de ITLC-SG (recomendado em 40, 70 e 41% das metodologias da FA, FE e IPEN, respectivamente), foi necessário buscar alternativas para sua substituição no controle radioquímico, avaliando-se suportes do tipo HPTLC (celulose e sílica gel) e Whatman (com diferenças de espessura e fluxo de corrida). Os resultados de % PRq determinada pelos métodos descritos na FA, FE, IPEN e os demais sistemas avaliados que apresentaram coeficiente de variação menor que 5% não foi considerada diferença significativa entre os métodos. Os sistemas cromatográficos avaliados neste trabalho podem ser utilizados em substituição ao suporte ITLC-SG. O HPTLC-celulose foi o suporte que apresentou tempo de análise, perfil cromatográfico e custo semelhante ao ITLC-SG, tornando-o um dos suportes mais indicados a ser utilizado como alternativa ao ITLC-SG nos 11 RL avaliados.<br>Radiopharmaceuticals are substances that have radioisotopes in their composition. About 95% of the procedures performed in nuclear medicine use radiopharmaceuticals with diagnostic pruposes, and the Lyophilized Reagents (LR) labeled with Technetium-99m (99mTc), obtained from 99Mo/99mTc generator, are the most one used. Quality Control represents the set of assays to be performed to assure that the product is adequate to its purpose. An important feature to be evaluated in 99mTc radiopharmaceuticals is the radiochemical purity (% RqP) to quantify free pertechnetate (99mTcO4 -) and technetium colloidal (99mTcO2) mainly by paper chromatography (PC), thin layer (TLC) and High Performance Liquid Chromatography (HPLC). The objective of this work was to perfom the comparison among the radiochemical control methodologies of LR labeled with 99mTc, described in the United States Pharmacopoeia (USP) and European Pharmacopoeia (EP) and those used by IPEN. 99mTcO4 - eluate and DISIDA, DMSA, DTPA, EC, ECD, GHA, MIBI, MDP, PIRO, SAH and Sn Coloidal LR were provided by IPEN-CNEN/SP. TLC-celulose, TLC-SG,TLC-SG reverse phase, HPTLC-celulose, HPTLC-SG (Merck) and ITLC-SG (Pall Corporation), W1MM, W3MM, W17M e W31ET (Whatman) chromatographic plates were used. The measurement of the radioactivity was done in a Perkin Elmer Cobra D-5002 gamma counter. LR were labeled to obtain 55,0 MBq mL-1 (1,5 mCi mL-1) of final radioactive concentration. The %99mTcO4 -, %99mTcO2 and % RqP were determined up to 4 hour labeling. From 11 LR, only EC and GHA have no radiochemical control methods in USP and EP. In USP and/or EP, DTPA, MDP, PIRO, SAH and Sn Coloidal methods use ITLC-SG; IPEN uses this chromatography plate in DISIDA, EC, ECD, GHA, PIRO, MIBI and SAH. As ITLC-SG had been out of production (recommended in 40, 70 and 41% of the USP, EP and IPEN methodologies, respectively), it was necessary to search alternatives to replace ITLC-SG plate in the radiochemical control, comparing with HPTLC (cellulose and silica gel) and Whatman plates (with thickness and flow rate differences). The % RqP results determined by the methods described in USP, EP, IPEN and the methods evaluated in this work presented coefficient of variation less than 5%, and it was not considered a significant value among the methods. Some chromatographic systems evaluated in this work can be used as replacement to the ITLC-SG plate. HPTLC-cellulose was the plate that presented time of analysis chromatography profile and cost similar to ITLC-SG, making it one of the most indicated to replace ITLC-SG, in 11 LR evaluated.
35
Lopuch, Miroslaw [Verfasser], and Armin [Akademischer Betreuer] Buschauer. "Investigations on neuropeptide Y and histamine receptors by fluorescence-based and radiochemical methods / Miroslaw Lopuch. Betreuer: Armin Buschauer." Regensburg : Universitätsbibliothek Regensburg, 2011. http://d-nb.info/1022872621/34.
Full text
36
Quinn, S. "Evaluation of a radiochemical method to estimate the rate of solute diffusion within a dual porosity Chalk aquifer." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1352527/.
Full textAbstract:
This thesis investigates a potential radiochemical method for estimating the capacity of the dual porosity Chalk aquifer to attenuate solutes. Solutes are advected by groundwater flow through fractures, but are slowed and attenuated by molecular diffusion into immobile water in the Chalk matrix. Fracture apertures are a key factor controlling rates of both advection and diffusion. The radiochemical model suggests that apertures may be estimated by comparing radon activity in groundwater with uranium-series isotope activities in the matrix. This estimate would be of great value if both radon release and solute attenuation are dominated by molecular diffusion. The thesis tests the assumptions made in the radiochemical method through a series of laboratory experiments and field observations. This has been achieved by use of • liquid-liquid extraction and luminescence spectrometry to assay Chalk core for uranium; and, • energy-discriminated liquid scintillation to determine both the radium activity of Chalk core and the radon activity in springs and pumped groundwater. The data demonstrate that • the Chalk does not possess a homogeneous distribution of radon precursors, which are dependent on both lithology and disequilibrium within the decay chain; • radon activity of pumped groundwater is highly variable and dependent on both the rate and duration of pumping; and, • spring sources demonstrate variation in radon activity which are not readily explained by the prevailing hydrogeological conditions. At a research site in Berkshire, double-porosity behaviour is shown to dominate solute transport, which can be characterised by an effective diffusion time. However, there is a clear disparity between diffusion times calculated from artificial tracer testing and estimated by the radiochemical method. This suggests that the radiochemical diffusion model is not appropriate in its current form to estimate rates of solute diffusion between fractures and the surrounding Chalk matrix.
37
GASIGLIA, HAROLDO T. "Estudos sobre a formacao do complexo do sup(153)Sm com EDTMP (acido etilenodiaminotetrametileno-fosfonico) e dos complexos do sup(153)Sm com outros fosfonatos, em temperatura ambiente." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10887.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:45:09Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:04:09Z (GMT). No. of bitstreams: 1
07013.pdf: 6587866 bytes, checksum: e1c1d18518e5c83a812cb4dc4c0cb496 (MD5)<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
38
Fiedler, Luise [Verfasser], and Guido [Akademischer Betreuer] Böning. "Diagnostic and therapeutic applications of CA XII targeting 6A10 Fab : radiochemical and biological studies / Luise Fiedler ; Betreuer: Guido Böning." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1176409794/34.
Full text
39
Furukawa, Cássia Yumi. "Avaliação de alguns fatores interferentes na estabilidade radioquímica de alguns radiofármacos marcados com 99mTc." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-09022018-083115/.
Full textAbstract:
Os radiofármacos são fármacos que possuem em sua composição um radionuclídeo e são utilizados para diagnóstico e tratamento de diversas doenças na medicina nuclear. O principal objetivo desse trabalho foi avaliar o efeito da temperatura e umidade na estabilidade de alguns reagentes liofilizados ALBUMINA-TEC, CIS-TEC, DEX-500-TEC, DEX-70-TEC, DISI-TEC, DMSA-TEC, DTPA-TEC, FITA-TEC, PUL-TEC, MIBI-TEC, MDP-TEC, PIRO-TEC, e TIN-TEC. Foi utilizada uma câmara climática para expor amostras destes produtos a uma temperatura de 40 °C e 75% de umidade relativa por 48 horas, para simular uma condição de transporte. Foram avaliadas duas situações: após um determinado tempo de armazenamento em temperatura de 2 - 8 °C, amostras de RL foram expostas por 48 horas em 40 °C e 75% UR e em seguida foram analisadas enquanto outras amostras foram colocadas por 48 horas em 40 °C e 75% UR, mantidas em temperatura de 2 - 8 °C até a validade do radiofármaco e analisadas quanto à pureza radioquímica e biodistribuição. Os radiofármacos ALBUMINA-TEC, DEX-70-TEC, DEX-500-TEC, DISI-TEC, DMSA-TEC, DTPA-TEC, PIRO-TEC, MDP-TEC, MIBI-TEC e MDP-TEC apresentaram resultados de % PRq e biodistribuição que atenderam às especificações, enquanto que CIS-TEC, PUL-TEC e TIN-TEC apresentaram alguns valores de % PRq menor que o especificado. TIN-TEC apresentou % PRq de 84% em um de três lotes, enquanto PUL-TEC apresentou % PRq de 88% em um de quatro lotes analisados; CIS-TEC é um RL que ainda precisa melhor analisado pois os resultados fora do especificado no controle radioquímico e biológico foram obtidos com um produto fora da validade especificada. Estes resultados indicaram que a pureza radioquímica pode ser afetada pela condição de estudo, o que não foi confirmado pelo controle biológico.<br>Radiopharmaceuticals are pharmaceuticals that have in their composition a radionuclide and are used for diagnosis and treatment of various diseases in nuclear medicine. The main objective of this study was to evaluate the effect of temperature and humidity on the stability of some lyophilized reagents: ALBUMINA-TEC, CIS-TEC, DEX-500-TEC, DEX-70-TEC, DISI-TEC, DMSA-TEC, DTPA-TEC, FITA-TEC, PUL-TEC, MIBI-TEC, MDP-TEC, PIRO-TEC and TIN-TEC. A climatic chamber was used for exposing some samples of these products to a temperature of 40 °C and 75% RH for 48 hours to simulate a transport condition. Two situations were evaluated: after a certain storage time at 2 - 8 °C, LR samples were exposed for 48 hours at 40 °C and 75% RH and analyzed while other samples were placed for 48 hours at 40 °C and 75% RH, kept at 2 - 8 °C until the expiration time of each radiopharmaceutical and analyzed for radiochemical purity and biodistribution. ALBUMINA-TEC, DEX-70-TEC, DEX-500-TEC, DISI-TEC, DMSA-TEC, DTPA-TEC, PIRO-TEC, MDP-TEC, MIBI-TEC and MDP-TEC presented results of % RCP and biodistribution that met the specifications while CIS-TEC PUL-TEC and TIN-TEC presented some % RCP lower than specified. TIN-TEC presented % RCP of 84% in one of three lots while PUL-TEC presented % RCP of 88% in a one of four batches analyzed; CIS-TEC is a LR that further need to be analyzed because probable the out of specification results of radiochemical and biological controls were obtained with a product outside of the validity date. These results indicated that radiochemical purity, can be affected by study condition, which has not been confirmed by biological control.
40
Khandal, Dhriti. "Traitement sous rayonnement ionisant de mélanges amidon-lignine et de leurs modèles : étude et quantification des modifications induites." Thesis, Reims, 2012. http://www.theses.fr/2012REIMS021/document.
Full textAbstract:
Cette travail été réalisée dans le cadre de la Projet LignoStarch ANR CP2D pour connaître les différents phénomènes induite par rayonnement ionisants dans les mélanges de l'amidon et lignine au niveau moléculaire. L'amidon peut être utilisé seul ou en combinaison avec d'autres composés pour élaborer des articles biodégradables à partir de ressources renouvelables. La lignine et ses dérivés sont bons candidats pour limiter la sensibilité d'eau des matériaux à base d'amidon, mais ils ne sont pas compatibles avec des polysaccharides. Le traitement sous faisceau d'électrons est proposé comme une méthode efficace pour induire les liaisons covalentes entre les deux constituants (amidon et lignine). En comparaison avec les mélanges de départ, les propriétés des mélanges irradiés montrent qu'il est possible d'ajuster les propriétés mécaniques du matériau final. Afin d'améliorer la compréhension et la maîtrise de ces effets de l'irradiation, une étude de mélanges modèles de maltodextrines et de divers alcools ou acides aromatiques a été réalisée. Les résultats montrent une compétition entre les phénomènes de dégradation par scission et le greffage. Les analyses par CES, RMN, et MALDI-TOF permettent de mettre en évidence et de quantifier les greffages consécutifs à l'irradiation. L'exploitation par la méthode statistique proposée par Saito des données relatives à l'évolution des masses molaires et des fractions de gel dans des mélanges à base de pullulane permet d'accéder à des grandeurs quantifiant l'efficacité des deux réactions en compétition. Ainsi, les rendements radiochimiques de coupure de chaine G(S) et de pontage G(X) ont pu être calculés pour différentes quantités d'alcool cinnamique introduites dans les mélanges. Les évolutions observées rendent bien compte de la formation de gel qui n'est observée qu'en présence d'une quantité minimale d'alcool aromatique, lorsque la condition G(s) < 4 G(x) est satisfaite. Mots Clés : Amidon, Lignine, Maltodextrine, Maltotriose, Pullulane, Composés Modèles de la Lignine (Additif Aromatiques), Scission, Réticulation, Greffage, Faisceau d'Electrons, Rendements Radiochimiques de Scission G(s) et Réticulation G(x), Méthode Saito, Méthode Charlesby-Pinner<br>This work was part of the LignoStarch ANR CP2D Project aimed at understanding the radiation-induced processes and mechanisms in thermoplastic starch – lignin mixture at the molecular level. Starch has the advantage of being biodegradable and agriculture based renewable resource that can be converted into a thermoplastic material with or without any additive. Lignin and its derivatives are good candidates for reducing the water sensitivity of starch based materials; however being hydrophobic in nature they are not compatible with the polysaccharides. Electron Beam radiation has been proposed as an efficient method for modifying the starch lignin blends and creating covalent linkages between the two constituents for improved blend stability. Previous studies as part of the Project have shown that the mechanical properties of the irradiated blends can be positively modified by choosing an appropriate blend composition. For a better understanding of how the properties of the blend can be tailored, an understanding of the radiation-induced processes was carried out using model blends comprising maltodextrin and different aromatic compounds having structural features of lignin monomers. The blends were analyzed using SEC, NMR, and MALDI-TOF for placing in evidence the phenomenon of radiation-induced grafting to compete with chain scission in presence of the aromatic additives. The quantification of the radiochemical yields of scission G(s) and crosslinking G(x) were carried out using the blends of pullulan polysaccharide as a function of varying amounts of aromatic additive in the blend. The methods of calculation exploited here are based on the study of radiation-induced molecular mass changes before the formation of gel as proposed by Saito and the quantification of sol-gel content for formulations resulting in gel as proposed by the Charlesby-Pinner method. The condition of gel formation G(s) < 4 G(x) is found to be valid for a certain minimum quantity of aromatic additive for high applied doses.Keywords: Starch, Lignin, Maltodextrin, Pullulan, Lignin-like Monomers (Aromatic Additives), Scission, Crosslinking, Grafting, Electron Beam, Radiochemical yields of Scission G(s) and Crosslinking G(x), Saito Method, Charlesby-Pinner Method
41
Thomas, Dale D. III. "Radiochemical methods and results used to characterize concentrations of radioactive material in soil at the former McClellan Air Force Base (AFB)." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17613.
Full text
42
Davies, Sarah J. "The radiochemical evolution of the Devonian Orcadian Basin, NE Scotland and comparison with coeval clastic systems from Wales, Norway and the Clair Field." Thesis, University of Leicester, 1993. http://hdl.handle.net/2381/35012.
Full textAbstract:
This thesis examines the radiochemistry of the Devonian sediments of the Orcadian Basin, NE Scotland, the Hornelen Basin, SW Norway, together with the SW Wales. A detailed study of the radiochemistry linked to standard sedimentological and geochemical techniques has permitted the utility of portable gamma-ray spectrometry to be assessed. There are no systematic stratigraphic changes in the relative abundances of K, U, Th or in the ratios Th/K and Th/U for either lacustrine or non-lacustrine sediments of the Devonian Orcadian Basin. Spatial radioelement variations related to lithology and source chemistry are more important for characterising the basin infill. Palaeoenvironmental reconstructions, combining sedimentology and radiochemistry, are presented for stages in the evolution of the northern Orcadian Basin. Differing K abundances from the Sandwick lacustrine sequence indicate separation of two depositional areas by a buried basement ridge. The different provenance of the southern and northern marginal fans in the Hornelen Basin, Norway, is reflected by Th and K. Provenance links between the basement and the marginal breccias of the Turriff Basin could be characterised radiochemically and were distinct from the main Lower Old Red Sandstone sediments derived from the Strichen granite. Gamma-ray characteristics linking basement and sediments elsewhere in the Orcadian Basin were less conclusive, implying that the local basement was a minor contributor to the sediment budget. Uranium enrichment is associated with (i) sediments in close proximity to Caledonian granitic basement and (ii) lacustrine intervals. U enrichment is a product of both syndepositional fixation in algal sediments and limited later mobilisation, predominantly restricted to the vicinity of the basement with the greatest concentration along synsedimentary faults. U (5 ppm) and Th (8 ppm) abundances define the zone of mineralisation associated with algal sediments. Lacustrine intervals were correlated using U only for widespread lacustrine conditions; as lacustrine intervals become marginal, U concentrations decrease and correlations are speculative. Lacustrine laminites are geochemically distinguished from sandflat sediments having higher Zr, Y, Cr, Nb, V and SiO2 contents.
43
Shehata, Mohamed Mostafa Mostafa Verfasser], Syed M. [Akademischer Betreuer] [Qaim, and Heinz [Akademischer Betreuer] Coenen. "Radiochemical Studies Relevant to Cyclotron Production of the Radionuclides 71,72As, 68Ge/68Ga and 76,77,80mBr / Mohamed Mostafa Mostafa Shehata. Gutachter: Syed Qaim ; Heinz Coenen." Köln : Universitäts- und Stadtbibliothek Köln, 2011. http://d-nb.info/1038065038/34.
Full text
44
Fonollosa, García Elena. "Impacte radiològic ambiental causat per la industrialització al tram baix del riu Ebre." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/399532.
Full textAbstract:
En aquesta tesi doctoral s’han determinat els diferents radionúclids tant d’origen natural com artificial en mostres ambientals. Aquestes mostres estudiades estan sota la influencia de la industrialització de la conca del riu Ebre. Concretament en aquesta zona es troben localitzades la central nuclear d’Ascó, la industria de fosfat bicàlcic i finalment, la planta de tractament d’aigua potable. Totes aquestes indústries poden afectar radiològicament a la qualitat de l’aigua del riu Ebre.
Per altra banda, també s’han avaluat les concentracions d’activitat dels radionúclids d’origen natural en diferents tipus de mol·luscs que es cultiven a la desembocadura del riu Ebre, concretament al delta de l’Ebre. L’interès d’aquest estudi recau en la importància de fer una estimació de les dosi per ingesta d’aquests aliments a través de la dieta.<br>En esta tesis doctoral se han determinado los diferentes radionucleidos tanto de origen natural como artificial en muestras ambientales. Estas muestras estudiadas están bajo la influencia de la industrialización de la cuenca del río Ebro. Concretamente en esta zona se encuentran localizadas la central nuclear de Ascó, la industria de fosfato bicálcico y finalmente, la planta de tratamiento de agua potable. Todas estas industrias pueden afectar radiológicamente a la calidad del agua del río Ebro.
Por otra parte, también se han evaluado las concentraciones de actividad de los radionucleidos de origen natural en diferentes tipos de moluscos que se cultivan en la desembocadura del río Ebro, concretamente en el delta del Ebro. El interés de este estudio recae en la importancia de hacer una estimación de las dosis por ingesta de estos alimentos a través de la dieta.<br>In this thesis we have determined the different radionuclides of both natural and artificial origin in environmental samples. These samples studied are under the influence of industrialization of the Ebro river basin. Specifically in this area are located Asco nuclear power plant, dicalcium phosphate industry and finally the water treatment plant. All these industries may affect radiologically the water quality of the Ebro river.
On the other hand, we have also evaluated the activity concentrations of naturally occurring radionuclides in different types of molluscs cultivated in the mouth of the Ebro River, specifically in the Ebro delta. The interest of this study lies in the importance of estimate the dose intake of these foods through the diet.
45
Siddeeg, Saif Eldin Mohammed Babiker. "Geochemistry of natural radionuclides in uranium-enriched river catchments." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/geochemistry-of-natural-radionuclides-in-uraniumenriched-river-catchments(c32e80c3-413a-4513-a0a6-fd3a705abd99).html.
Full textAbstract:
Radionuclides from natural U-series in sediments from two river catchments in the UK have been studied. The aim was to gain insight into the behaviour of 238U, 234U, 230Th and 226Ra in real natural systems enriched in uranium. A radiochemical method for radium separation followed by alpha spectrometric measurement has been developed. The method allowed use of 225Ra, in equilibrium with the parent 229Th, as a yield determinant, and has been applied in 226Ra concentrations measurements in the selected areas of study.U-series progeny, 238U, 234U, 230Th and 226Ra, in totally dissolved sediments from the valley of the River Noe and the fraction leached by aqua regia, have been measured. Total sediment contents ranged from 9 ± 2 to 184 ± 8 Bq.kg-1 for uranium, 9 ± 3 to 200 ± 13 Bq.kg-1 for thorium and 18 ± 1 to 179 ± 8 Bq.kg-1 for radium. The activity concentrations in the leached fractions, compared with the total, were 46% for uranium, 54% for thorium and 56% for radium, on average. The radionuclides showed extensive disequilibrium and this suggested a complex leaching/accumulation of uranium as well as an impact of organic matter and secondary minerals.Uranium and radium have been geochemically characterised in sediments from near the South Terras abandoned uranium mine, Cornwall. Background activity concentration levels of uranium in sediments ranged from 13 ± 3 to 290 ± 14 Bq.kg-1, with radium from 42 ± 4 to 424 ± 23 Bq.kg-1. Elevated concentrations of uranium and radium were measured in two samples, S3 with 1820 ± 36 Bq.kg-1 for uranium and 940 ± 53 Bq.kg-1 for radium; and S7 with 4350 ± 53 Bq.kg-1 for uranium and 1765 ± 48 Bq.kg-1 for radium. Sequential chemical extraction for the two samples revealed that both uranium and radium were associated with organic and carbonate fractions, with 25 % of the uranium in the resistant phase of S7. 234U/238U activity ratios of the sequential extraction fractions showed different trends in the sediments, and this was linked to the impact of organic matter and/or exchange between water and sediment. Uranium-bearing minerals in association with potassium, calcium, iron, manganese and arsenic have been identified in these sediments.
46
GERALDO, BIANCA. "Utilização de métodos radioanalíticos para a determinação de isótopos de urânio, netúnio, plutônio, amerício e cúrio em rejeitos radioativos." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9942.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:33:04Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:06:06Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
47
Gauglitz, Érica. "Estudo e levantamento de parâmetros para montagem de um laboratório de produção de fontes radioativas utilizadas na verificação de equipamentos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-08082011-143953/.
Full textAbstract:
Este trabalho apresenta o levantamento de parâmetros para implementação adequada e segura de pisos, portas, janelas, bancadas, capelas entre outros, de um laboratório radioquímico. A disposição de cada item segue orientações de guias, normas nacionais da Comissão Nacional de Energia Nuclear (CNEN) e internacional da Agencia Internacional de Energia Atômica (IAEA), com objetivo de garantir a proteção radiológica do trabalhador e do ambiente. A disposição adequada dos itens do laboratório radioquímico, garante a qualidade e segurança na produção de fontes radioativas seladas de 57Co 137Cs e 133Ba com atividades 185, 9.3 e 5.4 MBq respectivamente. Estas fontes são utilizadas na verificação de medidores de atividade, equipamento que todo Centro de Medicina Nuclear deve ter disponível segundo recomendações da norma CNEN-NN-3.05 Requisitos de Radioproteção e Segurança para Serviços de Medicina Nuclear para verificação da atividade de radiofármacos que serão administrados nos pacientes para fins de diagnóstico e terapia. Um medidor de atividade fora adquirido pelo laboratório de produção de fontes, com o qual foram realizados os testes de precisão, exatidão, reprodutibilidade e linearidade, que devem apresentar resultados dentro dos limites estabelecidos na norma CNEN-NN-3.05.<br>This paper presents a survey of parameters for the proper and safe flooring, doors, windows, fume hoods and others, in a radiochemical laboratory. The layout of each item follows guidelines and national standards of the National Commission of Nuclear Energy (CNEN) and the International Atomic Energy Agency (IAEA), aiming to ensure the radiological protection of workers and environment. The adequate items arrangement in the radiochemical laboratory ensures quality and safety in the production of 57Co 137Cs and 133Ba radioactive sealed sources, with activities 185, 9.3 and 5.4 MBq, respectively. These sources are used to verify meter activity equipment and should be available throughout the Nuclear Medicine Center, following the recommendations of CNEN-NN-3.05 standard \"Requirements for Radiation Protection and Safety Services for Nuclear Medicine\", to verify the activity of radiopharmaceuticals that are administered in patients, for diagnosis and therapy.
48
Begg, Fiona H. "Anthropogenic '1'4C in the natural (aquatic) environment." Thesis, University of Glasgow, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300458.
Full text
49
MAIHARA, VERA A. "Avaliacao do conteudo de alguns elementos essenciais e toxicos em dietas de criancas e idosos pelo metodo de analise por ativacao de neutrons." reponame:Repositório Institucional do IPEN, 1996. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10445.
Full textAbstract:
Made available in DSpace on 2014-10-09T12:38:48Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T13:59:55Z (GMT). No. of bitstreams: 1
02808.pdf: 3051127 bytes, checksum: ee0b80e362c14864a245ed624e93fff2 (MD5)<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
50
MORA, TAMIRES de A. "Avaliação da concentração de atividade de Ra-226, Ra-228 e Pb-210 em sedimentos provenientes da Antártica na região da Baía do Almirantado." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26077.
Full textAbstract:
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-04-08T12:24:41Z
No. of bitstreams: 0<br>Made available in DSpace on 2016-04-08T12:24:41Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado em Tecnologia Nuclear)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP