Sample records for fluorates
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Mass spectrometric investigation of fluorated europium β-diketonates
International Nuclear Information System (INIS)
Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Suboch, V.P.; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)
1983-01-01
Ternary complexes of europium with two organic lidands - fluorated β-diketone and organic base - in the aqueous phase at electron shock are investigated; regroupings that take place in them are established. Mass-spectrometric investigation has shown that complexes with β-diketones, containing in oxygen atom in a fluorated radical, eliminate stable molecules of difluorophosgen, CoF 2 . For the complexes studied under the above conditions the Co molecule elimination is also typical which is accompanied by the formation of ions with a metal-carbon bond
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Mass spectrometric investigation of fluorated europium. beta. -diketonates. [Electrons
Energy Technology Data Exchange (ETDEWEB)
Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Suboch, V.P. (AN Belorusskoj SSR, Minsk. Inst. Fiziki; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)
Ternary complexes of europium with two organic ligands - fluorated ..beta..-diketone and organic base - in the aqueous phase at electron shock are investigated; regroupings that take place in them are established. Mass-spectrometric investigation has shown that complexes with ..beta..-diketones, containing in oxygen atom in a fluorated radical, eliminate stable molecules of difluorophosgen, CoF/sub 2/. For the complexes studied under the above conditions the Co molecule elimination is also typical which is accompanied by the formation of ions with a metal-carbon bond.
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International Nuclear Information System (INIS)
Khomenko, V.S.; Pavich, T.A.; Lozonskij, M.O.; Fialkov, Yu.A.; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)
1987-01-01
Methods of mass-spectrometry, luminescent specroscopy and thermogravimetry are used to study decomposition ways, structure and volatility of mixed europium and neodymium complexes with fluorated organic ligands and bisheterocycles. It is shown that complexes containing an oxygen atom in a fluorated ligand elimination of difluorophosgene and tetrafluoroethylene molecules takes place. The addition of a bisheterocyclic ligand to a triligand complex makes the averaged bond in the complex more covalent and increase its volatility
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S.T.M.I.: Several years of experience in nuclear plant dismantling
International Nuclear Information System (INIS)
Moreau, J.C.
1986-01-01
Since 1977, when STMI performed its first dismantling operation, the Company appreciably improved in that field through important operations: the dismantling of the calciothermy and fluoration metal Pu preparation facility, in La Hague reprocessing plant, the dismantling of the slag treatment chain, associated to calciothermy and fluoration processes, in La Hague reprocessing plant, the cleaning of EL4 cell in Marcoule. To perform these operations, STMI's operating teams, on top of decontamination and dismantling technologies, strived to improve handling and transportation technologies, and to nuclearize many equipments. In order to increase its technical efficiency, STMI signed a cooperation agreement with TECHNICATOME company. Therefore, the union between the operational know-hows of STMI and the design experience of TECHNICATOME allow the needs of any customs facing a dismantling case to be satisfied [fr
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STMI: several years of experience in nuclear plant dismantling
International Nuclear Information System (INIS)
Moreau, J.C.
1985-01-01
Since 1977, when STMI performed its first dismantling operation, the Company appreciably improved in that field through important operations: the dismantling of the calciothermy and fluoration metal Pu preparation facility, in La Hague reprocessing plant; the dismantling of the slag treatment chain, associated to calciothermy and fluoration processes, in La Hague reprocessing plant; and the cleaning of EL4 cell in Marcoule. To perform these operations, STMI's operating teams, on top of decontamination and dismantling technologies, strived to improve handling and transportation technologies, and to nuclearize many equipments. In order to increase its technical efficiency, STMI signed a cooperation agreement with FRAMATOME company. Therefore, the union between the operational know-hows of STMI and the design experience of TECHNICATOME allow the needs of any customs facing a dismantling case to be satisfied [fr
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Energy Technology Data Exchange (ETDEWEB)
Vandenbussche, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires
1964-12-15
The study of fluorination reactions of uranium and plutonium compounds with elementary fluorine, has been carried out using a thermogravimetric method. These reactions are heterogeneous ones, and of the following type: S(solid) + G{sub 1}(gas) - G{sub 2}(gas). The kinetics of these reactions correspond to a uniform attack of the entire surface of the sample. {alpha}: being the degree of completion of the reaction, k(rel): being the relative rate of penetration of the reaction interface, t: being the time, one have the relation: (1-{alpha}){sup 1/3} = 1 - k(rel)*t. The mechanism of the reaction varies according to the nature of the compound: 1) with uranium tetrafluoride and plutonium tetrafluoride, the reaction proceeds in a single step; 2) with uranium oxides, the reaction proceeds in two steps, uranium oxyfluoride being the intermediate compound; 3) with plutonium oxide, the reaction proceeds in two steps, plutonium tetrafluoride being the intermediate compound; and 4) with uranium trichloride, the mechanism is complex: chlorine trifluoride is formed. (author) [French] L'etude des reactions de fluoration par le fluor, de composes de l'uranium et du plutonium a ete faite par thermogravimetrie. Ce sont des reactions heterogenes du type: S(solide) + G{sub 1}(gaz) - G{sub 2}(gaz). La cinetique de ces reactions est celle correspondant a une attaque uniforme de toute la surface de l'echantillon. Si {alpha}: est le degre d'avancement de la reaction, k(rel): est la vitesse relative d'avancement d'un interface reactionnel, t: le temps. On a la relation: (1-{alpha}){sup 1/3} = 1-k(rel)*t. Le mecanisme de la reaction varie selon la nature du compose: 1) tetrafluorure d'uranium et tetrafluorure de plutonium, la reaction s'effectue en un seul stade; 2) Oxydes d'uranium: la reaction s'effectue en deux stades, l'oxyfluorure d'uranium est le compose intermediaire; 3) oxyde de plutonium, la reaction s'effectue en deux stades, la tetrafluorure de plutonium est le compose
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Treatment of uranium turning with the controllable oxidizing process
International Nuclear Information System (INIS)
Shen Bingyi; Zhang Yonggang; Zhen Huikuan
1989-02-01
The concept, procedure and safety measures of the controllable oxidizing for uranium turning is described. The feasibility study on technological process has been made. The process provided several advantages such as: simplicity of operation, no pollution environment, safety, high efficiency and low energy consumption. The process can yield nuclear pure uranium dioxide under making no use of a great number of chemical reagent. It may supply raw material for fluoration and provide a simply method of treatment for safe store of uranium turning
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Development and simulation of various methods for neutron activation analysis
International Nuclear Information System (INIS)
Otgooloi, B.
1993-01-01
Simple methods for neutron activation analysis have been developed. The results on the studies of installation for determination of fluorine in fluorite ores directly on the lorry by fast neutron activation analysis have been shown. Nitrogen in organic materials was shown by N 14 and N 15 activation. The description of the new equipment 'FLUORITE' for fluorate factory have been shortly given. Pu and Be isotope in organic materials, including in wheat, was measured. 25 figs, 19 tabs. (Author, Translated by J.U)
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Spectra of fluorinated rare earth β-diketonates with added ligands
International Nuclear Information System (INIS)
Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Krasovskaya, L.I.; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)
1984-01-01
Different-ligand rare earth complexes are synthesized. Fluorated β-diketones, triethylphosphine oxide and trifluoracetic acid are used as active ligands. Mass-spectra of low and high resolution are taken at the energy of ionizing electrons of 70 eV, as well as luminescence spectra of complexes. Fragmentation ways of complexes decomposition under electron shock are studied. A series of changing the bound strength of additional ligands with europium in mixed complexes is determined. It is shown that the introduction of additional ligands can purposefully change physical and chemical properties of complexes
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Spectra of fluorinated rare earth. beta. -diketonates with added ligands
Energy Technology Data Exchange (ETDEWEB)
Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Krasovskaya, L.I. (AN Belorusskoj SSR, Minsk. Inst. Fiziki; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)
1984-01-01
Different-ligand rare earth complexes are synthesized. Fluorated ..beta..-diketones, triethylphosphine oxide and trifluoracetic acid are used as active ligands. Mass-spectra of low and high resolution are taken at the energy of ionizing electrons of 70 eV, as well as luminescence spectra of complexes. Fragmentation ways of complexes decomposition under electron shock are studied. A series of changing the bound strength of additional ligands with europium in mixed complexes is determined. It is shown that the introduction of additional ligands can purposefully change physical and chemical properties of complexes.
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General description of new equipment 'Fluorite-III' for Bor-Oendoer fluorate factory
International Nuclear Information System (INIS)
Bayar, V.; Basankhueue, O.; Ganzorig, J.; Dushan, P.; Lodoisamba, S.; Otgooloi, B.; Tsehlmehg, A.; Shagjjamba, D.
1992-01-01
A new equipment 'Fluorite-III' is described which is used to register and analyze three kinds of following informations: 1. Pulse count for determination of ore's concentration which is transferring by the factory conveyor. 2. Pulse count for determination of ore's thickness which is transferring also by the factory conveyor. 3. Information about that: Is the conveyor moving or not during our measurements. First and second kinds of information are registered by two detectors which is established on the different places from the factory conveyor. Constraction of these detectors are the same. Every one of them consists of a ''photo multiplier tube'' and a scintillator of ''sodium-iodine''. The third information is corresponding to the ''transistor and transistical logic'' level. Every counters data and the information about the conveyor should be transferred every time to the computer which is compatible with the IBM/PC for further treatment through the following devices: 1. Three State Buffer which is made from ''Generic Array Logic'' device. 2. Universal Asynchronous Receiver and Transmitter (UART) which is of type (AY 3-1015). 3. 20 milli-ampere current interface with optical isolators. Also in this way but in reverse order by these devices we can control all processes of the measurements from the computer. 1 fig
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Energy Technology Data Exchange (ETDEWEB)
Gendre, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1962-07-01
facteurs physiques sur la vitesse de fluoration du tetrafluorure de plutonium solide par le fluor. Dans un appareil a four horizontal et circulation de fluor a la pression atmospherique de 520 deg. C, avec un debit de fluor pur de 9 l.h{sup -1}, il est possible de transformer une charge de 3 g de tetrafluorure en hexafluorure avec un taux de transformation d'environ 100 pour cent et un rendement de recuperation superieur a 90 pour cent, en 4 a 5 h. La vitesse de fluoration est fonction de la temperature du debit de fluor, de la surface de la nacelle, de l'epaisseur de la couche de tetrafluorure et du temps de reaction. Elle ne depend pas de la diffusion du fluor dans le Solide mais est commandee par la reaction a l'interface gaz-solide et suit la loi cinetique (1 - T{sub T}){sup 1/3} = kt + 1. L'existence de fluorures intermediaires, en particulier Pu{sub 4} F{sub 17}, est confirmee par une cassure de la droite d'Arrhenius vers 370 deg. C, par des differences dans les vitesses de fluoration au sein de la couche de tetrafluorure et par des variations reversibles de coloration. La transformation en hexafluorure s'accompagne d'une purification vis-a-vis des elements etrangers entrant dans la composition de plutonium initial. Recuperation du plutonium des scories d'elaboration: L'etude est basee sur la transformation en hexafluorure gazeux des grains de plutonium occlus dans les scories d'elaboration, cet hexafluorure devant fournir par decomposition thermique un tetrafluorure directement recyclable au stade elaboration. - Dans les conditions envisagees, ce procede n'est pas utilisable industriellement. Apres broyage, une Reparation par milieu dense (iodure de methylene) permet de separer une scorie enrichie en plutonium (75 pour cent du Pu dans 2,6 pour cent du poids des scories) et une scorie pauvre. Par fluoration prolongee (16 h) des diverses portions recueillies, il est possible de recuperer environ 80 pour cent du plutonium. Un appareillage de traitement base sur la
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International Nuclear Information System (INIS)
Cermak, V.; Markvart, M.; Novy, P.; Vanka, M.
1989-01-01
The tests are briefly described or proportioning U 3 O 8 powder of a granulometric grain size range of 0-160 μm using a vertical screw, a horizontal dual screw and a vibration dispenser with a view to proportioning very fine U 3 O 8 powder fractions produced in the oxidation of UO 2 fuel pellets. In the tests, the evenness of proportioning was assessed by the percentage value of the proportioning rate spread measured at one-minute intervals at a proportioning rate of 1-3 kg/h. In feeding the U 3 O 3 in a flame fluorator, it is advantageous to monitor the continuity of the powder column being proportioned and to assess it radiometrically by the value of the proportioning rate spread at very short intervals (0.1 s). (author). 10 figs., 1 tab., 12 refs
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International Nuclear Information System (INIS)
Colnago, Luiz A.; Vaz, Carlos M.P.
1997-01-01
The utilization of herbicides in the agriculture has been becoming a practice more and more controlled by national and international laws, as these compounds are highly toxic and used in large amounts. Therefore, it is necessary to establish accurate, low cost, and fast analytical chemical procedures for the correct determination of commercial composition of herbicides. This work evaluated the utilization of low resolution nuclear magnetic resonance for the quantitative chemical analysis of trifluraline herbicide in commercial formulas. Results are presented
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Energy Technology Data Exchange (ETDEWEB)
Lima, Tatiana A. Fernandes de; Oliveira, Elizabeth Kerpe de; Rios, Francisco Javier [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: tafl@cdtn.br
2007-07-01
One of the preliminary stages for the choice of the appropriated local is the geological study. The granitic rocks are the best choice for construction of high level radioactive wastes repository. In the minerals associated to the rock there are small quantities of imprisoned fluids denominated fluid inclusions (FI), were heating coming from the waste radioactive decays can cause crackling of the wastes and migration of the fluids to the heat source. These studies require to be in routine a ultra heating platin (up to 1350 degree C) calibrated, coupled to the petrographic microscope (microthermometry). The tests performed viewed the calibration and placing into routine the platin, by using analytical standards such as fusion temperature covering the heating range (the substances potassium dichromate, barium nitrate, lithium fluorate copper and other two standards of Chaixmeca platin). The Leitz Heating Stage 1350 platin is presently installed and operating at Laboratory of Fluid Inclusions and Metallogenesis of the CDTN/Brazil, for using of this technique. (author)
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International Nuclear Information System (INIS)
Goryushko, A.G.; Davidenko, N.K.; Kudryavtseva, L.S.; Lozinskij, M.O.; Lugina, L.N.; Fialkov, Yu.A.
1980-01-01
Altogether five coordination compounds of europium (3) of the composition EuL 3 , wherein HL is a fluorinated beta-diketone containing in its fluorinated linear or cyclic radical a heteroatom, such as oxygen, have been obtained. The hygroscopicity of the obtained tris-beta-ketones has been tested. Their activity as lanthanide shifting agents for NMR spectroscopy purposes has been analyzed and the stability constants of their monoadducts with ethyl acetate have been determined [ru
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Energy Technology Data Exchange (ETDEWEB)
Boutot, P; Capitaine, A; Giachetto, I [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires
1962-07-01
Two solutions have been adopted: - removal of the material from its original container, treatment in a special container; - treatment of the material directly inside its original protective packing. The treatment of a fluorination oven illustrates the second process. After a thorough cleaning of the enclosure, the oven is fixed in and the contamination held in place by a varnish. The assembly is placed in a special container and covered with shaken-down concrete. The container is shut by means of a welded cover. The operations are carried out under reduced pressure. At the end of this process it is impossible to detect any residual radioactivity. (authors) [French] Deux solutions ont ete adoptees: - extraire le materiel de son enveloppe d'origine et le conditionner dans un container special; - conditionner le materiel directement a l'interieur de la protection d'origine. Le conditionnement d'un four de fluoration illustre le deuxieme procede. Apres un nettoyage complet de l'enceinte, le four en a ete rendu solidaire et la contamination a ete fixee au moyen d'un vernis. L'ensemble a ete place dans un container special et enrobe de beton vibre. Le container a ete ferme par un couvercle soude. L'ensemble des operations a ete realise sous depression. A la suite de ces operations aucune activite residuelle n'a ete decelee. (auteurs)
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Energy Technology Data Exchange (ETDEWEB)
Guillet, H
1959-02-01
A description is given of direct fluorination of pre-concentrated uranium ores in order to obtain the hexafluoride. After normal sulfuric acid treatment of the ore to eliminate silica, the uranium is precipitated by a load of lime to obtain: either impure calcium uranate of medium grade, or containing around 10% of uranium. This concentrate is dried in an inert atmosphere and then treated with a current of elementary fluorine. The uranium hexafluoride formed is condensed at the outlet of the reaction vessel and may be used either for reduction to tetrafluoride and the subsequent manufacture of uranium metal or as the initial product in a diffusion plant. (author) [French] Il s'agit d'une description de fluoration directe de preconcentres de minerais d'uranium en vue d'obtention d'hexafluorure. Apres attaque sulfurique normale du minerai, afin d' eliminer la silice, l' uranium est precipite par un toit de chaux pour obtenir: ou uranate de chaux impur de titre moyen, ou uranium de la dizaine du pourcentage. Ce concentre seche en atmosphere inerte est soumis a un courant de fluor elementaire. L'hexafluorure d'uranium forme est condense a la sortie du reacteur et peut etre utilise soit apres reduction en tetrafluorure par l'elaboration d'uranium metal, soit comme produit de base dans le cadre d'une usine de diffusion. (auteur)
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Energy Technology Data Exchange (ETDEWEB)
Guillet, H
1959-02-01
A description is given of direct fluorination of pre-concentrated uranium ores in order to obtain the hexafluoride. After normal sulfuric acid treatment of the ore to eliminate silica, the uranium is precipitated by a load of lime to obtain: either impure calcium uranate of medium grade, or containing around 10% of uranium. This concentrate is dried in an inert atmosphere and then treated with a current of elementary fluorine. The uranium hexafluoride formed is condensed at the outlet of the reaction vessel and may be used either for reduction to tetrafluoride and the subsequent manufacture of uranium metal or as the initial product in a diffusion plant. (author) [French] Il s'agit d'une description de fluoration directe de preconcentres de minerais d'uranium en vue d'obtention d'hexafluorure. Apres attaque sulfurique normale du minerai, afin d' eliminer la silice, l' uranium est precipite par un toit de chaux pour obtenir: ou uranate de chaux impur de titre moyen, ou uranium de la dizaine du pourcentage. Ce concentre seche en atmosphere inerte est soumis a un courant de fluor elementaire. L'hexafluorure d'uranium forme est condense a la sortie du reacteur et peut etre utilise soit apres reduction en tetrafluorure par l'elaboration d'uranium metal, soit comme produit de base dans le cadre d'une usine de diffusion. (auteur)
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Synthesis and characterization of fluorine compounds
International Nuclear Information System (INIS)
Martinez Carrillo, M.
1991-01-01
The ( 18 F) D-glucose, 2-deoxy fluorine ( 18 FDG) is a radio pharmaceutic that is used in nuclear medicine it is utilized mainly in the glucose metabolism. It allows recently to observe the tumors accumulation and growing. The obtention of this radio pharmaceutic can realize by a nucleophilic or electrophilic process through the use of different fluorinated agents obtained as intermediates for introducing the 18 F radionuclide in a final step of synthesis. The first methods already has been studied in the National Institute of Nuclear Research. The second one which is based this work and it was realized through the reaction of acetyl hypo fluorite (CH 3 COOF) with tri acetyl glucal (TAG) in turn they require the obtention of several fluorated compounds that they serve as intermediates for their obtention so that objective of this work was to find the adequate technique for the obtention of anhydride hydrofluoric acid (HF), KF.2 HF and elemental fluorine so as the design and construction of the systems and equipment used for carry out each one of the reactions. Moreover it was designed the system that will be used for the obtention of acetyl hypo fluoride and the synthesis of composite tetraacetilide 3,4,6 tri-D-glucopyranosil fluoride (TAG-F) for that finally by hydrolysis it was obtained the 2-deoxy fluoride-D-glucose (TAG) in inactive. In this system were realized several preliminary tests. The results are showed in the content of this work also the techniques for compounds characterization were given. (Author)
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Study of the oxidation behavior of zirconoium and its alloys
International Nuclear Information System (INIS)
Costa, I.
1985-01-01
The oxidation behavior of zirconium, zircaloy-4 and Zr-2,5% Nb alloy, as well as the influence of temperature, oxidising atmosphere, metal composition, heat treatment, surface treatment and specimen size on the oxidation of these materials in the temperature range 350 - 900 0 C and at atmospheric pressure have been studied with the aid of thermogravimetry. The results indicate that oxidation rate increases with temperature and the rate of oxidation of the zirconium alloys was appreciable beyond 600 0 C. At temperature higher than 500 0 C, the oxidation curves of the zirconium alloys revealed a rate transition, the kinetics after transition being either mixed parabolic and linear or linear. The transition produced an alteration in oxide characteristics, from being dark and adherent and protective, to white or grey and revealing at times cracks and scaling. The oxidation atmospheres were oxygen and air, and the results showed that the extent of oxidation in air was higher than that in oxygen. Among the metals, zirconium showed a low degree of oxidation, and the alloy Zr-2,5% Nb the lowest resistance to oxidation. Specimens heat treated in the α-phase showed the highest resistance to oxidation, and those heat treated in the β-phase the lowest. Surface treatments in aqueous solutions containing a high concentration of the fluoride ion, left behind fluorates on the surface and increased the oxidation rates of zirconium and zircaloy-4. Specimens with a high proportion of corners in relation to the total area, showed a high extent of oxidation giving rise to cracks in the oxide at the corners. (Author) [pt
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Energy Technology Data Exchange (ETDEWEB)
Albarghach, N. [CHU Morvan, 29 - Brest (France); Righini, C. [CHU Michallon, 38 - Grenoble (France); Thariat, J. [Centre Antoine-Lacassagne, 06 - Nice (France)
2009-10-15
The application of teeth casts with fluorinated gel is omitted in practice after six months for most of patients. The reasons can be an inadequate information on the application time of casts, mucitis pain during excessive application of fluorinated gel during irradiation creating then, apprehension of fluorinated gels. A questionnaire of observance during the consultation can be an education tool. repeated for the same patients at the next follow up consultation and compared it could allow to measure the impact of awareness measures during the follow up. (N.C.)
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Energy Technology Data Exchange (ETDEWEB)
Boutot, P; Capitaine, A; Giachetto, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1961-07-01
The furnace, 1.60 x 0. 75 x 0.80 m in dimensions, was placed inside a 2. 50 x 1.25 x 2 m glove box. The operations were as follows: - removal of the furnace from the glove box; - storage of the furnace in a special container ; - reduction to a minimum volume and elimination of the glove box. A very high {alpha} activity, oxidation of the various channeling, and waste products trapped in the box necessitated special safety measures such as fixing of the contamination, crushing, the use of appropriate vinyl envelopes. This long and tedious work was carried out with no resulting bodily or atmospheric contamination. (authors) [French] Le four de 1,60 x 0,75 x 0,80 m, etait place dans une boite a gants de 2,50 x 1,25 x 2 m. L'operation a consiste: - a extraire le four de la boite a gants; - a le stocker dans un container special; - a reduire a un volume minimum la boite a gants pour l'eliminer. Une activite {alpha} tres elevee, l'oxydation des differentes canalisations, les dechets occlus dans la boite ont exige des moyens de protection speciaux tels que l'encollage de la contamination, la mise en depression, l'emploi d'enveloppes de vinyle appropriees. Ce travail, long et fastidieux, a ete effectue sans entrainer de contamination corporelle ou atmospherique. (auteurs)
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Directory of Open Access Journals (Sweden)
Tereza Cristina Rocha Moreira de Oliveira
2010-07-01
Full Text Available Salmonellosis is a common and widespread zoonotic disease of humans and a frequent cause of foodborne disease. Treatment of severe and systemic salmonellosis is usually done with fluoroquinolones. In this review resistance mechanisms of Salmonella to quinolones are discussed. Single point mutations in the quinolone resistant determining region (QRDR of the gyrA gene may be sufficient to generate high levels of resistance to non-fluorated quinolones and also may decrease the fluoroquinolones susceptibility. Other resistance mechanisms that should be considered are mutations in parC gene, the possibility of acquiring resistance through plasmidial transference and hyper-expression of efflux pumps. Fluoroquinolones resistance is still relatively uncommon in Salmonella compared to other species belonging to the Enterobacteriaceae family. However, the more careful use of fluoroquinolones in veterinary and human medicine is essential to decrease the selective pressure which can avoid the emergence and spread of resistant clones and consequently maintain the clinical efficacy of this group of antibiotics.A salmonelose é uma zoonose de importância mundial e uma das mais freqüentes doenças de origem alimentar. As fluoroquinolonas são a principal opção para o tratamento de salmoneloses graves ou sistêmicas. Esta revisão de literatura teve como objetivo apresentar os principais mecanismos envolvidos na resistência de Salmonella spp a estes antimicrobianos. Mutações de ponto na Região Determinante de Resistência à Quinolona (QRDR do gene gyrA podem gerar altos níveis de resistência a quinolonas não-fluoradas, além de reduzir a suscetibilidade as fluoroquinolonas. Outros mecanismos de resistência que também precisam ser considerados são as mutações no gene parC, a possibilidade do envolvimento de plasmídios de resistência e o sistema de efluxo ativo. A resistência às fluoroquinolonas ainda é incomum em Salmonella spp., quando
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International Nuclear Information System (INIS)
Chatalov, V.V.; Kozlov, O.I.; Machirev, V.P.; Zvonarev, E.N.
1998-01-01
Full text: The works on technology and equipment for rare earths (RE) fluorides are very scarce. Presently RE-fluorides are manufactured by various methods. Conventionally they can be divided into two main groups. The first group comprises methods based on precipitation of fluorides from soluble salts of corresponding metals by fluohydric acid (aqueous methods) with following thermal decomposition of aquatic fluorides obtained until anhydric state is reached. The second group (called dry, gaseous or non-aqueous) comprises methods based on direct fluorizating (by fluorine hydride, fluor or other fluorating agents) have several important advantages compared to the aqueous methods: the fluorides obtained are anhydrous; the operations of fluoride precipitation, washing, decantation, filtration are excluded as well as their drying and calcination. The process of calcination is, as a rule, accompanied by pyrohydrolysis. The products manufactured by precipitation are inferior to those obtained by the non-aqueous technique. The world production practice uses both groups of methods. Nevertheless, the method of gaseous hydrofluorination is preferable. In all non-aqueous processes the initial materials are oxides RE which interact with gaseous fluorine hydride. The initial materials - oxides are obtained by thermal decomposition of carbonates, hydroxides, oxalates and so on. One of the best type of apparatus for thermal decomposition processes is a horizontal ring shaped vibrating apparatus with direct heating. The RE - fluorides is synthesized by way of RE-oxide interacting with hydrogen fluoride at 200-550 deg C in single continuous operation: (RE) 2 O 3 + 6 HF → 2 (RE)F 3 + 3 H 2 0 The apparatus consists of a nickel horizontal two tube screw. Reaction time is varied from 2 to 6 hours; the productivity of reactor is defined by feed screw rotation and initial material bulk density. Hydrogen fluoride was passing the reactor opposite to the solid phase. The degree
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Energy Technology Data Exchange (ETDEWEB)
Faugeras, P; Chesne, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires
1964-07-01
Improvements made in the conventional tri-butylphosphate process are described, in particular. the concentration and the purification of plutonium by one extraction cycle using tri-butyl-phosphate with reflux; and the use of an apparatus working continuously for precipitating plutonium oxalate, for calcining the oxalate, and for fluorinating the oxide. The modifications proposed for the treatment of irradiated uranium - molybdenum alloys are described, in particular, the dissolution of the fuel, and the concentration of the fission product solutions. The solvent extraction treatment is used also for the plutonium fuels utilized for the fast breeder reactor (Rapsodie) An outline of the process is presented and discussed, as well as the first experimental results and the plans for a pilot plant having a capacity of 1 kg/day. The possible use of tn-lauryl-amine in the plutonium purification cycle is now under consideration for the processing plant at La Hague. The flowsheet for this process and its performance are presented. The possibility of vitrification is considered for the final treatment of the concentrated radioactive wastes from the Marcoule (irradiated uranium) and La Hague (irradiated uranium-molybdenum) Centers. Three possible processes are described and discussed, as well as the results obtained from the operation of the corresponding experimental units using tracers. (authors) [French] On decrit les ameliorations apportees au procede classique utilisant le phosphate tributylique, et notamment la concentration et la purification du plutonium par un cycle d'extraction au tributylphosphate avec reflux, l'utilisation d'un appareillage continu de precipitation d'oxalate de plutonium, de calcination de l'oxalate, et de fluoration de l'oxyde. On presente les modifications envisagees pour le traitement des alliages uranium-molybdene irradies, principalement en ce qui concerne la dissolution du combustible et la concentration des solutions de produits de fission
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Energy Technology Data Exchange (ETDEWEB)
Darras, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1963-02-15
, un changement important d'energie d'activation du processus d'oxydation se produit systematiquement, mais aussi a une temperature variable suivant l'atmosphere consideree. Cependant, dans le cas des alliages, la cinetique d'oxydation lineaire classique est generalement precedee de courtes periodes d'induction, a caractere parabolique. On a ensuite mis en evidence et interprete deux possibilites d'inhibition de ia corrosion du magnesium par la vapeur d'eau: soit a la suite d'une fluoration superficielle partielle, soit lorsque le gaz porteur est l'anhydride carbonique. D'autre part, les conditions extremes de l'oxydation, c'est-a-dire les phenomenes d'inflammation qui surviennent a une temperature bien determinee dans chaque atmosphere, ont fait l'objet d'une etude particuliere. Enfin, on s'est efforce de degager la portee de l'ensemble de ces resultats aux deux points de vue fondamental et pratique. (auteur)
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Kursheva, Anna; Petrova, Vera; Litvinenko, Ivan; Morgunova, Inna
2017-04-01
Information about the hydrocarbons content (including aromatic ones) in components of geologic environment allows to define common factors in distribution and correlation both nature and technogenic component, and also to reveal the sources of contamination. At that, it should be noted, that hydrocarbons are widely spread in lithosphere and create steady geochemical background, variations are caused here by specifics of initial organic matter, conditions of its accumulation and transformation. The basis of the study are the samples of sea water and deep sea sediments (more than 600 stations), collected in western sector of Arctic region (Pechora, Barents and Kara seas) during the scientific-research expeditions of FSBI "VNIIOkeangeologia" for the period 2000-2010. Total content of aromatic hydrocarbons was defined by spectrofluorometric method using analyzer «FLUORAT-Panorama-02». Certification of data was performed on representative samples based on contents and molecule structure of polycyclic aromatic hydrocarbons using GC-MS (Agilent 5973/6850 GC-MS System). Results of spectrofluorometric analysis of lipid fraction of organic matter of bottom sediments allowed to define specific parameters, which characterize various lithofacies groups of sediments. Thus, sandy residues are characterized by low level of aromatic hydrocarbons (ca. 4.3 μg/g) with prevalence of bi- and tri-aromatic compounds (λmax 270-310 nm). This correlates with low sorption capacity of coarse-grained sediments and absence of organic-mineral component, containing the breakdown products of initial organic matter. Tetra- and penta- aromatic structures prevail in clay sediments (ca. 13.0 μg/g), which are typical components of lipid fraction of organic matter of post sedimentation and early diagenetic stages of transformation. At that, changes of spectral characteristic of sediments in stratigraphic sequence completely reflect processes of diagenetic transformation of organic matter, including
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Directory of Open Access Journals (Sweden)
Rosa Fernanda IGNÁCIO
1999-01-01
Full Text Available Avaliou-se o efeito de um dentifrício contendo bicarbonato de sódio na contagem de estreptococos do grupo mutans (EM, acidogenicidade e composição da placa dental. Vinte e três voluntários escovaram os dentes 3 vezes ao dia, com formulações fluoretadas (1.500 ppm F, contendo, ou sílica (SÍLICA, ou carbonato de cálcio (CARBONATO, ou carbonato de cálcio mais bicarbonato de sódio (CARB/BICAR, num delineamento duplo cego cruzado, com 3 etapas de 30 dias. No 28º dia, 8 a 12 horas após a última escovação, foi realizada a contagem de estreptococos do grupo mutans na saliva (EMS. No 30º dia (após 2 dias, nos quais os voluntários bochecharam 3 vezes/dia uma suspensão do dentifrício em água, e 6 vezes/dia sacarose a 10%, analisou-se na placa dental, após 10 a 12 horas do último bochecho de dentifrício: a contagem de mutans (EMP; b polissacarídeos álcali solúveis (PSA; c flúor solúvel em ácido (FSA; d pH no tempo zero (T0, após 5 minutos de bochecho com sacarose (T5, calculando-se o DpH (T0-T5. Os resultados (média + erro padrão para SÍLICA, CARBONATO e CARB/BICAR foram respectivamente:1 EMS (x106 UFC/ml saliva = 11,43 + 7,62 A; 2,33 + 1,04 A; 2,07 + 1,10 A; 2 EMP (x106 UFC/mg placa = 0,099 + 0,095 A; 0,027 + 0,018 A; 0,007 + 0,003 A; 3 PSA (mg/mg placa = 6,89 + 0,62 AC; 8,46 + 0,80 AB; 6,11 + 0,59 C; 4 FSA ((mg/g placa = 36,67 + 10,10 A; 48,12 + 19,23 A; 52,21 + 15,12 A; 5 T0 = 6,72 + 0,12 A; 6,88 + 0,13 A; 6,65 + 0,11 A; 6 T5 = 5,61 + 0,13 A; 5,71 + 0,13 A; 5,70 + 0,12 A; 7 DpH = 1,12 + 0,11 A; 1,17 + 0,11 A; 0,95 + 0,10 A, sendo que médias seguidas por letras distintas diferem entre si ao nível de 5% de significância. Os resultados demonstram que, embora o dentifrício contendo bicarbonato de sódio tenha apresentado, coletivamente, uma tendência a influenciar positivamente nos diversos fatores relacionados à cárie dental, não diferiu significantemente dos dentifrícios contendo carbonato de cálcio ou sílica como abrasivo.This investigation evaluated the effect of a fluoride baking soda-containing dentifrice on mutans streptococci counting, acidogenicity and composition of dental plaque. Twenty-three volunteers brushing their teeth 3 times a day, tested 3 formulations of fluoride (1500 ppm F, containing or sodium bicarbonate (12% associated with calcium carbonate (CARB/BICAR, or calcium carbonate (CARBONATE, or silica (SILICA, in a double blind crossover trial, done in 3 phases of 30 days each. On the 28th day, 8-10 hours after the last brushing, a counting of mutans streptococci in saliva (SMS was made. On the 30th day (after 48 hours during which the subjects were instructed to rinse with a slurry of toothpaste/water 3 times a day and sucrose 10% 6 times a day, the effect was analyzed in dental plaque, 10-12 hours after the last rinse: a mutans streptococci (PMS; b polysaccharide alkali-soluble (ASP; c acid-soluble F (ASF and d pH in T0 (T0, 5 min. after cariogenic challenge (T5, calculating DpH (T0 - T5. The results (mean + SE according to the treatments with dentifrices SILICA, CARBONATE and CARB/BICAR, were respectively: 1 SMS (x 106 UFC/mL saliva = 11.43 + 7.62 A; 2,33 + 1.04 A; 2.07 + 1.10 A; 2 PMS (x 106 UFC/mg = 0.099 + 0.095 A; 0.027 + 0.018 A; 0.007 + 0.003 A; 3 ASP (mg/mg = 6.89 + 0.62 AC; 8.46 + 0.80 AB; 6.11 + 0.59 C; 4 ASF (mg/g = 36.67 + 10.10 A; 48.12 + 19.23 A; 52.21 + 15.12 A; 5 T0 = 6.72 + 0.12 A; 6.88 + 0.13 A; 6.65 + 0.11 A; 6 T5 = 5.61 + 0.13 A; 5.71 + 0.13 A; 5.70 + 0.12 A; 7 DpH = 1.12 + 0.11 A; 1.17 + 0.11 A; 0.95 + 0.10 A. Means followed by the same letter do not differ significantly (P < 0.05. The data show that although the baking soda-containing dentifrice demonstrated, collectively, a trend to influence positively the various factors of dental caries, it did not differ significantly from SILICA and CARBONATE dentifrices.
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Corrosion of copper by chlorine trifluoride; Corrosion du cuivre par le trifluorure de chlore
Energy Technology Data Exchange (ETDEWEB)
Vincent, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1966-07-01
chlore a ete effectuee, et controlee par chromatographie gazeuse, microsublimation et spectrographie infra-rouge. Les essais ont porte sur des cuivres de differentes puretes, principalement sur le cuivre a 99,999, sous forme de monocristaux. Ils ont comporte des cinetiques et la caracterisation des produits de corrosion dans differentes conditions de temperature et de pression. Les cinetiques ont montre des reactions du meme ordre de grandeur que celles obtenues avec le fluor-element. A pression atmospherique, il se forme du fluorure cuivrique et du chlorure cuivreux. La presence de ce compose permet d'ecarter definitivement l'assimilation du ClF{sub 3} a un simple agent fluorant. Aux basses pressions, un compose inconnu a ete caracterise. Il existe une tres forte presomption pour qu'il s'agisse du fluorure cuivreux instable, qui n'a pas pu etre encore isole. Un phenomene de germination a ete mis en evidence, montrant les analogies des phases initiales de fluoration avec celles de l'oxydation. Des effets importants resultant de la dissociation des fluorures de cuivre et de la solubilite du chlore dans ce metal ont ete mis en evidence. En dernier lieu, des essais ont montre l'influence considerable de la purete de la phase gazeuse et de la nature des parois sur les vitesses de corrosion qui peuvent dans certains cas etre multipliees par plusieurs puissances de dix. (auteur)
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Energy Technology Data Exchange (ETDEWEB)
Machurek, J. E.; Stein, M. H. [Division of Isotopes Development, USAEC, Washington, DC (United States)
1963-11-15
des rayonnements ionisants. Les auteurs donnent les resultats de quatorze de ces travaux; certains sont decrits succinctement dans le memoire et d'autres sont exposes en detail dans les comptes rendus. Les sujets traites sont les suivants: 1. Preparation de produits bois-matiere plastique en utilisant des rayons gamma pour induire la polymerisation. 2. Emploi du rayonnement beta des produits de fission pour l'hydrogenation de la houille et de ses derives pour produire des hydrocarbures liquides. 3. Production de semi-conducteurs dans lesquels on repartit les impuretes selon un schema spatial fixe a l'avance, a l'aide de transmutations neutroniques. 4. Polymerisation radioinduite de l'ethylene et de ses copolymeres. 5. Etude fondamentale du mecanisme et de la cinetique des reactions radioinduites. 6. La. radiochimie dans la fluoration de divers composes aromatiques. 7. Emploi de monomeres polyfonctionnels pour augmenter la radioreticulation du polyethylene, du polypropylene, du polyisobutylene et de l'acetate de cellulose. 8. Effets du gonflement, des contraintes et d e la temperature sur les proprietes physiques et chimiques des polymeres produits au moyen des rayonnements. 9. Influence des facteurs structurels sur les modifications radioinduites dans les polymeres conduisant a la copolymerisation par greffage. 10. Utilisation des rayonnements pour modifier les proprietes de matieres textiles. 11. Reactions radioinduites utilisant le krypton-85. 12. Preparation d'un ''Manuel des rayonnements''. 13. Utilisation de la liaison organometallique en dosimetrie des rayons gamma intenses. 14. Mise au point d'un dosimetre a cellule solaire. (author) [Spanish] Dentro del marco de su programa de fomento de la irradiacion industrial, la Comision de Energia Atomica de los Estados Unidos ha emprendido una amplia serie de investigaciones cuyo objetivo principal es estimular un progreso tecnologico que facilite el empleo de las radiaciones ionizantes en la produccion industrial. Los