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. M.C. Roberts 1996 Tetracycline resistance determinants: mechanisms of action, regulation of expression, genetic mobility and distribution FEMS Microbiol Rev

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177 436 438 Barbosa, T. M., Scott, K. P. and Flint, H. J. (1999): Evidence for recent intergeneric transfer of a new tetracycline resistance gene

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as wound curative, while the solid copolymers could find application in micro- and nanoencapsulation of drugs [ 8 ]. Tetracycline hydrochloride is a highly water-soluble drug, which acts as an antibiotic and anti-collagenase and has also been reported

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Solvent extraction studies using tetracycline as complexing agent

XIV. Study of the behaviour of tetracycline as an extracting agent for some fission products

Journal of Radioanalytical and Nuclear Chemistry
Authors: I. Cunha and M. Nastasi

Abstract  

The behaviour of tetracycline as an extracting agent for strontium, iodine, barium, molybdenum, technetium, zirconium, niobium, cesium, ruthenium, tellurium and uranium has been studied and the influence of the acidity of the aqueous phase upon extraction of the elements mentioned has been examined. Experiments have been made to determine whether or not the species extracted into the organic phase is the complex formed between tetracycline and the elements considered as well as to determine the time of shaking necessary so that the equilibrium between the phases is attained. As a practical application, the possibility of using the tetracycline-benzyl alcohol system for separating the fission products137Cs,140Ba,140La,141Ce,103Ru,95Zr and95Nb from each other and from uranium is presented. The same study has been made for131I,99mTc,99Mo,132Te,239Np and uranium and the steps necessary for the separation of these elements are proposed.

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Solvent extraction studies using tetracycline as a complexing agent

XII. Determination of stability constants for the complexes of uranium and tetracycline

Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Saiki and L. Tarenzi

Abstract  

Stability constants for uranium-tetracycline complexes were determined by the method of average number of ligands, the method of limiting values, the method of two parameters and the method of weighted least squares. Solvent extraction technique was used to obtain experimental data.

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Solvent extraction studies using tetracycline as a complexing agent

X. Determination of the stability constants for the complexes of thorium and tetracycline

Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Saiki and F. Lima

Abstract  

Stability constants for thorium complexes with tetracycline were determined by the methods of average number of ligands, the limiting value, the two parameters and by weighted least squares. The solvent extraction technique was used to obtain the required data for the determination of the constants.

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Abstract  

The use of the antibiotic agent tetracycline for analytical purposes in solvent extraction procedures is presented. Individual extraction curves for the lanthanides, zinc, scandium, uranium, thorium, neptunium and protactinium were obtained. Separation of those elements one from another, and of uranium from selenium, bromine, antimony, barium, tantalum and tungsten was carried out. In all cases benzyl alcohol was the diluent used to dissolve tetracycline hydrochloride. Sodium chloride was used as supporting electrolyte for the lanthanide separations and sodium perchlorate for the other elements mentioned. Stability or formation constants for the lanthanide complexes as well as for thorium complex with tetracycline were determined by using the methods of average number of ligands, the limiting value (for thorium), the two parameters and the weighted least squares. For the lanthanides, the stability constants of the complexes Ln(TC)3 go from 9.35±0.22 for lanthanum up to 10.84±0.11 for lutetium. For the Th(TC)4 complex the formation constant is equal to 24.6±0.3. Radioisotopes of the respective elements were used for the determinations. When more than one radioelement was present in an experiment, a multichannel analyser coupled to Ge(Li) or NaI(Tl) detectors was used for counting the activities. When only one radioisotope was used, counting of the radioisotopes was made with a single-channel analyser (integral mode counting) coupled to a NaI(Tl) detector. Uranium was determined by activation analysis (epithermal neutrons). Radioisotopes of the elements were obtained by irradiation in the IPEN swimming-pool reactor. The natural radioisotope2 3 4Th was used as label in the thorium experiments. In some separation procedures such as in the case of the pair uranium-neptunium, and of the pair scandium-zinc, the separation was obtained by properly adjusting the pH value of the aqueous phases, before the extraction operation. In other cases, addition of masking agents to the extraction system was required in order to perform the separation between the elements under study. In this way ethylenediaminetetraacetic acid (EDTA) was used as masking agent for scandium and the lanthanides in order to allow separation of uranium from those elements. Diethylenetriaminepentaacetic acid (DTPA) was used as masking agent for thorium in order to extract uranium into the organic phase. Separations of protactinium from thorium, and of uranium from protactinium and thorium, were accomplished by using sodium fluoride as masking agent for protactinium and DPTA as masking agent for thorium and protactinium at the same time. In the case of the separation of the lanthanides one from another it is necessary to resort to a multi-stage extraction procedure since the stability constants for those elements are too close.

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Solvent extraction studies using tetracycline as a complexing agent

XV. Separation of interferences in neutron activation analysis of lanthanides in rocks

Journal of Radioanalytical and Nuclear Chemistry
Author: M. Saiki

Abstract  

A chemical procedure has been developed for the separation of U, Th, Fe, Sc, Na, Ta and Mo, which interfere in neutron activation analysis of the lanthanide elements in rocks. This methods in based on the extraction of interferents, before irradiation of the samples, using a solution of tetracycline in benzyl alcohol. The lanthanide elements remain in the aqueous phase and are coprecipitated with calcium oxlate or ferric hydroxide for irradiation and subsequent determination by gamma-ray spectrometry. Conditions for the separation of these interferences are examined determining the extraction curves. The chemical separation procedure was applied in the analysis of lanthanides in geological materials and the results showing the accuracy and the reproducibility of the method are presented. The sensitivity for all the lanthanides was determined.

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Abstract  

Tetracycline in solution of benzyl alcohol was used as an extracting agent to separate uranium from interfering elements in the determination of uranium and of isotopic ratio235U/238U by neutron activation analysis. Separation gives a recovery of 97% for uranium and the interferences from matrices of pitchblende and monazite are eliminated.

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Abstract  

Hydrogen ion dependence and extractant dependence of the extraction of the lanthanide elements, scandium, uranium and thorium into a solution of tetracycline in benzyl alcohol have been determined. Possiblity of using the tetracycline-benzyl alcohol system for separation of the lanthanide elements present in a mixture, as well as for the separation of uranium from those elements was tested. In the first case discontinuous countercurrent technique was used. In the second case a single step solvent extraction procedure was applied.

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