Zeitschriftenartikel: „Acide tellurique“

1

Dicko, Adama Aguissa, und Et Al. „Mélioïdose cutanée : A propos d’un cas au Mali“. Revue Malienne d'Infectiologie et de Microbiologie 17, Nr. 1 (30.04.2022): 97–99. http://dx.doi.org/10.53597/remim.v17i1.2236.

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La mélioïdose est une zoonose bactérienne transmise par voie aérienne et cutanée, due à un bacille tellurique Burkholderia pseudomallei. C’est une infection sévère par ces complications viscérales. Elle est observée essentiellement en Asie du Sud-Est et au Nord de l’Australie. En Afrique et particulièrement au Mali, elle est rarement observée. Nous rapportons le cas d’un monsieur de 25 ans, malien, chauffeur mécanicien sans antécédents médico-chirurgicaux particuliers reçu en août 2021 pour des lésions papuleuses persistantes du visage survenues à la suite d’une longue panne de véhicule dans les broussailles de Kita une région du sud du Mali à pluviométrie élevée. A l’examen on notait un état général conservé, une fièvre à 38°C et un IMC à 22 Kg/m2. Au niveau cutané, on observait des lésions papulo-pustuleuses et nodulaires par endroits prédominant au visage et quelques-unes au dos. Le reste de l’examen clinique était normal. L’examen bactériologique du pus a mis en évidence la présence d’assez nombreuses colonies de Burkholderia pseudomallei qui étaient sensible à l’imipénème et intermédiaire à l’amoxicilline-acide clavulanique. Le reste du bilan était normal. Le patient a été traité par l’amoxicilline-acide clavulanique avec une disparition des lésions en 15 jours. La mélioïdose doit être toujours évoquée devant des lésions papulo-nodulaires et pustuleuses dans un contexte de séjour dans une zone humide.

2

Kiriyak, Ludmila. „The effect of thiazine dyes on polarographic determination of tellurium“. Collection of Czechoslovak Chemical Communications 56, Nr. 1 (1991): 216–22. http://dx.doi.org/10.1135/cccc19910216.

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The effect of thionine, azure I and methylene blue on the electroreduction of tellurium(IV) has been studied in the solutions of oxalic, tartaric and trihydroxyglutaric acids. It has been shown that the electrode process is complicated by adsorption of all components of the electrochemical reaction. This causes an increase of the tellurium analytical signal. The determinations is not hampered by great excesses of various elements. Optimal conditions were found according to which determinations were carried out of tellurium in binary mixtures Pb-Te, Cd-Te, Fe-Te, Bi-Te and of tellurium admixtures in bismuth of high purity, doped by tellurium.

3

Chen, Cen, und Zhen Huang. „Tellurium-Modified Nucleosides, Nucleotides, and Nucleic Acids with Potential Applications“. Molecules 27, Nr. 23 (01.12.2022): 8379. http://dx.doi.org/10.3390/molecules27238379.

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Tellurium was successfully incorporated into proteins and applied to protein structure determination through X-ray crystallography. However, studies on tellurium modification of DNA and RNA are limited. This review highlights the recent development of Te-modified nucleosides, nucleotides, and nucleic acids, and summarizes the main synthetic approaches for the preparation of 5-PhTe, 2′-MeTe, and 2′-PhTe modifications. Those modifications are compatible with solid-phase synthesis and stable during Te-oligonucleotide purification. Moreover, the ideal electronic and atomic properties of tellurium for generating clear isomorphous signals give Te-modified DNA and RNA great potential applications in 3D crystal structure determination through X-ray diffraction. STM study also shows that Te-modified DNA has strong topographic and current peaks, which immediately suggests potential applications in nucleic acid direct imaging, nanomaterials, molecular electronics, and diagnostics. Theoretical studies indicate the potential application of Te-modified nucleosides in cancer therapy.

4

Tremaroli, Valentina, Matthew L. Workentine, Aalim M. Weljie, Hans J. Vogel, Howard Ceri, Carlo Viti, Enrico Tatti et al. „Metabolomic Investigation of the Bacterial Response to a Metal Challenge“. Applied and Environmental Microbiology 75, Nr. 3 (01.12.2008): 719–28. http://dx.doi.org/10.1128/aem.01771-08.

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ABSTRACT Pseudomonas pseudoalcaligenes KF707 is naturally resistant to the toxic metalloid tellurite, but the mechanisms of resistance are not known. In this study we report the isolation of a KF707 mutant (T5) with hyperresistance to tellurite. In order to characterize the bacterial response and the pathways leading to tolerance, we utilized Phenotype MicroArray technology (Biolog) and a metabolomic technique based on nuclear magnetic resonance spectroscopy. The physiological states of KF707 wild-type and T5 cells exposed to tellurite were also compared in terms of viability and reduced thiol content. Our analyses showed an extensive change in metabolism upon the addition of tellurite to KF707 cultures as well as different responses when the wild-type and T5 strains were compared. Even in the absence of tellurite, T5 cells displayed a “poised” physiological status, primed for tellurite exposure and characterized by altered intracellular levels of glutathione, branched-chain amino acids, and betaine, along with increased resistance to other toxic metals and metabolic inhibitors. We conclude that hyperresistance to tellurite in P. pseudoalcaligenes KF707 is correlated with the induction of the oxidative stress response, resistance to membrane perturbation, and reconfiguration of cellular metabolism.

5

Srivastava, Prem C., Furn F. Knapp und George W. Kabalka. „NEW RADIOHALOGENATED ALKENYL TELLURIUM FATTY ACIDS“. Phosphorus and Sulfur and the Related Elements 38, Nr. 1-2 (Juli 1988): 49–58. http://dx.doi.org/10.1080/03086648808079700.

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6

Silva, Marcio S., und Daniel Pietrobom. „Chiral discrimination of β-telluride carboxylic acids by NMR spectroscopy“. New Journal of Chemistry 39, Nr. 11 (2015): 8240–44. http://dx.doi.org/10.1039/c5nj01877c.

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7

Kudr, Jiri, Lukas Nejdl, Sylvie Skalickova, Michal Zurek, Vedran Milosavljevic, Renata Kensova, Branislav Ruttkay-Nedecky et al. „Use of nucleic acids anchor system to reveal apoferritin modification by cadmium telluride nanoparticles“. Journal of Materials Chemistry B 3, Nr. 10 (2015): 2109–18. http://dx.doi.org/10.1039/c4tb01336k.

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8

Ramadan, Shadia E., A. A. Razak, A. M. Ragab und M. El-Meleigy. „Incorporation of tellurium into amino acids and proteins in a tellurium-tolerant fungi“. Biological Trace Element Research 20, Nr. 3 (Juni 1989): 225–32. http://dx.doi.org/10.1007/bf02917437.

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9

Kut, D., M. Kut, M. Onysko und V. Lendel. „SYNTHESIS OF THIAZOLOQUINAZOLINARYLTELLURID“. Scientific Bulletin of the Uzhhorod University. Series «Chemistry» 47, Nr. 1 (23.09.2022): 78–83. http://dx.doi.org/10.24144/2414-0260.2022.1.78-83.

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Symmetric and asymmetric chalcogenides of organic nature are a class of organometallic compounds that are widely used as intermediates in a number of organic reactions, as ligands in the chemistry of coordination compounds, they have a wide range of biological activity. Diaryl tellurides, which are important for the formation of new carbon-carbon bonds, have a special area in the chemistry of organotelluric compounds. The synthesis of new representatives of this class of tellurium-containing compounds is an urgent task. One of the main methods of obtaining of diaryl tellurides is the interaction of arylboronic acids with diarylditellurides in the presence of various metal-containing catalysts or microwave radiation. In this paper, we have considered the method of obtaining asymmetric tellurides by the reaction of reduction of sodium sulfite with salts of thiazoloquinazolinaryl dichlorotellurides without the usage of catalysts. It was found that the reaction of 2-((dichloro(4-methoxyphenyl)-4-tellanyl)methyl)-2,3-dihydro-5H-thiazolo[2,3-b]quinazolin-5-one hydrochloride with triple excess of sodium sulfite leads to the formation of 2-((4-methoxyphenyl)tellanyl)methyl)-2,3-dihydro-5H-thiazolo [2,3-b]quinazolin-5-one. It should be noted that the recovery does not break the bond Te-C. In the analysis of spectral data, the signals of the protons of the thiazole cycle and the exocyclic aryltelluric fragment undergo a strong field shift. Thus, as a result of the reduction reaction of 2-((dichloro(4-methoxyphenyl)-4-tellanyl)methyl)-2,3-dihydro-5H-thiazolo[2,3-b]quinazolin-5-one hydrochloride, a biologically promising and suitable for further functionalization telluride was received.

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Dittmer, Donald C., Dmitry V. Avilov, Venkata Subbarao Kandula, Matthew T. Purzycki, Zachary J. Martens, Elliot B. Hohn und Matthew W. Bacler. „Tetramic acids and derivatives by telluride-triggered Dieckmann cyclizations“. Arkivoc 2010, Nr. 6 (09.12.2009): 61–83. http://dx.doi.org/10.3998/ark.5550190.0011.608.

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11

Ho, Peter C., Hilary A. Jenkins, James F. Britten und Ignacio Vargas-Baca. „Building new discrete supramolecular assemblies through the interaction of iso-tellurazole N-oxides with Lewis acids and bases“. Faraday Discussions 203 (2017): 187–99. http://dx.doi.org/10.1039/c7fd00075h.

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The supramolecular macrocycles spontaneously assembled by iso-tellurazole N-oxides are stable towards Lewis bases as strong as N-heterocyclic carbenes (NHC) but readily react with Lewis acids such as BR₃ (R = Ph, F). The electron acceptor ability of the tellurium atom is greatly enhanced in the resulting O-bonded adducts, which consequently enables binding to a variety of Lewis bases that includes acetonitrile, 4-dimethylaminopyridine, 4,4′-bipyridine, triphenyl phosphine, a N-heterocyclic carbene and a second molecule of iso-tellurazole N-oxide.

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Biebl, Hanno, Rüdiger Pukall, Heinrich Lünsdorf, Stefan Schulz, Martin Allgaier, Brian J. Tindall und Irene Wagner-Döbler. „Description of Labrenzia alexandrii gen. nov., sp. nov., a novel alphaproteobacterium containing bacteriochlorophyll a, and a proposal for reclassification of Stappia aggregata as Labrenzia aggregata comb. nov., of Stappia marina as Labrenzia marina comb. nov. and of Stappia alba as Labrenzia alba comb. nov., and emended descriptions of the genera Pannonibacter, Stappia and Roseibium, and of the species Roseibium denhamense and Roseibium hamelinense“. International Journal of Systematic and Evolutionary Microbiology 57, Nr. 5 (01.05.2007): 1095–107. http://dx.doi.org/10.1099/ijs.0.64821-0.

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A slightly pink-coloured strain, strain DFL-11T, was isolated from single cells of the marine dinoflagellate Alexandrium lusitanicum and was found to contain the genes encoding two proteins of the photosynthetic reaction centre, pufL and pufM. 16S rRNA gene sequence analysis revealed that the novel strain belonged to the α-2 subgroup of the Proteobacteria and was most closely related to Stappia aggregata (97.7 % similarity), Stappia alba (98.0 %) and Stappia marina (98.0 %). Dark-grown cells of strain DFL-11T contained small amounts of bacteriochlorophyll a (bchl a) and a carotenoid. Cells of strain DFL-11T were rods, 0.5–0.7×0.9–3.0 μm in size and motile by means of a single, subpolarly inserted flagellum. The novel strain was strictly aerobic and utilized a wide range of organic carbon sources, including fatty acids, tricarboxylic acid cycle intermediates and sugars. Biotin and thiamine were required as growth factors. Growth was obtained at sea salt concentrations of between 1 and 10 % (w/v), at a pH between 6 and 9.2 and at a temperature of up to 33 °C (optimum, 26 °C). Nitrate was not reduced and indole was not produced from tryptophan. Strain DFL11T was resistant to potassium tellurite and transformed it to elemental tellurium. The major respiratory lipoquinone was ubiquinone 10 (Q10). The polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, an unidentified aminolipid and the glycolipid sulphoquinovosyldiacylglyceride. The fatty acids comprised 16 : 1ω7c, 16 : 0, 18 : 1ω7c, 18 : 0, 11-methyl 18 : 1ω6t, 11-methyl 20 : 1ω6t, 20 : 1ω7c, 22 : 0, 22 : 1 and the hydroxy fatty acids 3-OH 14 : 0, 3-OH 16 : 0 (ester-linked), 3-OH 18 : 0, 3-OH 20 : 1 and 3-OH 20 : 0, all of which are amide-linked. The DNA G+C value was 56 mol%. Comparative analysis of α-2 subgroup 16S rRNA gene sequences showed that the type species of the genus Stappia, Stappia stellulata, is only distantly related to S. aggregata (95.3 % sequence similarity). Based on the combination of the 16S rRNA gene sequence data, a detailed chemotaxonomic study and the biochemical and physiological properties of members of the genera Stappia, Pannonibacter and Roseibium, it is proposed that S. aggregata, S. alba, S. marina are transferred to a new genus, Labrenzia gen. nov., as Labrenzia aggregata comb. nov., Labrenzia alba comb. nov. and Labrenzia marina comb. nov. The type species of the new genus is Labrenzia alexandrii sp. nov., with strain DFL-11T (=DSM 17067T=NCIMB 14079T) as the type strain. The pufLM genes of the photosynthesis reaction centre were shown to be present in some, but not all, species of the new genus Labrenzia and they were identified for the first time in S. stellulata. In accordance with the new data collected in this study, emended descriptions are provided for the genera Pannonibacter, Roseibium and Stappia.

13

Drabowicz, Jozef, Wanda H. Midura und Dorota Krasowska. „ChemInform Abstract: Selenium and Tellurium (1,2,3)-Oxygen-Containing Acids and Derivatives“. ChemInform 43, Nr. 46 (18.10.2012): no. http://dx.doi.org/10.1002/chin.201246255.

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14

KAGAYA, YUTAKA, und HIROAKI ISAGO. „Rapid Reactions of Phthalocyanines with Tellurium Tetrachloride in Non-aqueous Solutions“. Journal of Porphyrins and Phthalocyanines 03, Nr. 06 (August 1999): 537–43. http://dx.doi.org/10.1002/(sici)1099-1409(199908/10)3:6/7<537::aid-jpp172>3.0.co;2-2.

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Rapid reactions of tetra(tert-butyl)phthalocyanine, H 2( tbpc ), and its zinc complex, [ Zn ( tbpc )], with tellurium tetrachloride ( TeCl 4) in non-aqueous solutions have been investigated. Upon mixing respective solutions containing the reactants, drastic spectral changes occurred in chloroform and toluene even at room temperature. The electronic spectra of the products indicated that the reactions involved an acid-base equilibrium where the phthalocyanines and tellurium tetrachloride acted as a Lewis base and a Lewis acid respectively. By monitoring the spectral changes based on various initial molar ratios of the reactants, the compositions of the products for each system have been determined. [ Zn ( tbpc )] formed a 1:1 ( tbpc : TeCl 4) adduct in both chloroform and toluene, showing the same spectra close to those of the known monoprotonated phthalocyanines. On the other hand, H 2( tbpc ) formed a 1:1 adduct in chloroform but a 1:3 adduct in toluene even though both products showed essentially the same spectra close to those of the known diprotonated phthalocyanines. Equilibrium constants have been calculated for the four systems. Magnetic circular dichroism (MCD) spectra of conjugated acids of phthalocyanines have been studied for the first time.

15

Belozerova, A. A., A. V. Mayorova und M. N. Bardina. „A technique for depositing iron, tungsten, molybdenum, and chrome in the determination of selenium and tellurium in alloy steel by ICP-AES method“. Industrial laboratory. Diagnostics of materials 90, Nr. 5 (22.05.2024): 5–11. http://dx.doi.org/10.26896/1028-6861-2024-90-5-5-11.

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Direct determination of the content of selenium and tellurium impurities in metallurgical materials by the method of inductively coupled plasma atomic emission spectroscopy (ICP-AES) is difficult due to spectral and non-spectral interference from macrocomponents present in the materials under study. The separation of micro-(Se, Te) and macro-components (Fe, W, Mo, Cr, Cu, Ni, Co) through preliminary precipitation is the goal of the study. The use of barium acetate and sodium fluoride as precipitants are shown to provide an effective separation of Se and Te from Fe, W, Mo, and Cr (the content in the analyzed solution is less than 0.1 wt.% of the original) and partial separation from Cu, Ni, and Co (the content in the analyzed solution from 25 to 55 wt.% of the original). Optimal conditions for the deposition of macrocomponents (Fe, W, Mo, Cr) and inhibition of the process of coprecipitation of selenium and tellurium on sediments of macrocomponents for their subsequent ICP-AES determination were determined. The optimal pH for the precipitation of macrocomponents equals 1. The optimal mass of precipitants (barium acetate and sodium fluoride) is 10 and 3 g, respectively. To inhibit the process of coprecipitation of selenium and tellurium on sediments of macrocomponents, it is proposed to use hydrofluoric acid. The optimal volume of hydrofluoric and hydrochloric acids for inhibiting the process of coprecipitation of analytes on sediments of macrocomponents was determined (3 and 6 cm3, respectively). The developed procedure for separating micro-Se, Te from macro-components was tested on standard samples of alloyed steels using the «spike» method. The technique is characterized by satisfactory accuracy and reproducibility, the limit of determination of analytes after separation of macrocomponents is 10–3 wt.%.

16

Pradenas, Gonzalo A., Waldo A. Díaz-Vásquez, José M. Pérez-Donoso und Claudio C. Vásquez. „Monounsaturated Fatty Acids Are Substrates for Aldehyde Generation in Tellurite-ExposedEscherichia coli“. BioMed Research International 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/563756.

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Reactive oxygen species (ROS) damage macromolecules and cellular components in nearly all kinds of cells and often generate toxic intracellular byproducts. In this work, aldehyde generation derived from theEscherichia colimembrane oxidation as well as membrane fatty acid profiles, protein oxidation, and bacterial resistance to oxidative stress elicitors was evaluated. Studies included wild-type cells as well as cells exhibiting a modulated monounsaturated fatty acid (MUFA) ratio. The hydroxyaldehyde 4-hydroxy 2-nonenal was found to be most likely produced byE. coli, whose levels are dependent upon exposure to oxidative stress elicitors. Aldehyde amounts and markers of oxidative damage decreased upon exposure toE. colicontaining low MUFA ratios, which was paralleled by a concomitant increase in resistance to ROS-generating compounds. MUFAs ratio, lipid peroxidation, and aldehyde generation were found to be directly related; that is, the lower the MUFAs ratio, the lower the peroxide and aldehyde generation levels. These results provide additional evidence about MUFAs being targets for membrane lipid oxidation and their relevance in aldehyde generation.

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O’Donnell, M. D., D. Furniss, V. K. Tikhomirov, D. Briggs, E. F. Smith und A. B. Seddon. „Surface properties of tellurite and fluorotellurite glasses“. Journal of Materials Research 22, Nr. 6 (Juni 2007): 1673–84. http://dx.doi.org/10.1557/jmr.2007.0223.

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The surface properties of some freshly cleaved, or polished, quaternary tellurite glasses (TeO2-ZnO-Na2O-Yb2O3and TeO2-ZnO-Na2O-GeO2) and a proposed ternary fluorotellurite core/clad optical fiber pair (TeO2-N a2O-ZnF2) were investigated by means of x-ray photoelectron spectroscopy and chemical durability. Semiquantitative chemical analysis of the x-ray photoelectron spectroscopy spectra of cleaved tungsten-tellurite and fluorotellurite glasses showed good agreement with the batched at.% values when taking into account the effects of processing (e.g., melt fluorine volatilization), and the samples seemed to exhibit negligible hydrolysis. However, spectra of polished surfaces did not yield useful data because of masking of the glass “signal” from organic contamination at the sample surface. The chemical durability of these glasses were studied; specifically, the glass resistance to the attack and the etchability of various acids (aqueous HF, H2SO4, and HCl), alkali (aqueous NaOH), and water at 15, 21, and 60 °C were obtained by simple mass loss experiments and optical microscopy. Based on the appearance of the glass surfaces after immersion in these solutions, aqueous HF was found to be the most promising etchant, however, infrared spectra showed that significant OH was introduced into the glass. Attack of the fluorotellurite glasses was found to proceed at a higher rate in water at 60 °C compared with room temperature, and at both temperatures was shown to be diffusion controlled, with an Arrhenian activation energy estimated as 57 kJ mol−1.

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Kumar, Archana, und Donald C. Dittmer. „Synthesis of Intermediates for the Lactone Moiety of Mevinic Acids via Tellurium Chemistry“. Journal of Organic Chemistry 59, Nr. 17 (August 1994): 4760–64. http://dx.doi.org/10.1021/jo00096a017.

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19

Karlsson, Erik, Jörg Neuhausen, Robert Eichler, Alexander Vögele und Andreas Türler. „Adsorption properties of iodine on fused silica surfaces when evaporated from tellurium in various atmospheres“. Journal of Radioanalytical and Nuclear Chemistry 326, Nr. 1 (28.08.2020): 711–18. http://dx.doi.org/10.1007/s10967-020-07326-y.

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Abstract The evaporation of iodine containing species from tellurium has been investigated together with their adsorption behavior on a fused silica surface. In inert gas, the formation of two species was observed with adsorption enthalpies of around − 90 to − 100 and − 110 to − 120 kJ/mol, respectively. For reducing environments, a single species identified as monatomic iodine was observed with an adsorption enthalpy around − 95 kJ/mol. In oxidizing conditions, species with low adsorption enthalpies ranging from − 65 to − 80 kJ/mol were observed. Presumably, these are iodine oxides as well as oxo-acids of iodine (HIOx). The results of the thermochromatography experiments performed here prove the usefulness of the employed production method for carrier-free iodine isotopes and enhance the understanding of the evaporation and deposition behavior of iodine under various chemical conditions.

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Darbani, Behrooz, Vratislav Stovicek, Steven Axel van der Hoek und Irina Borodina. „Engineering energetically efficient transport of dicarboxylic acids in yeast Saccharomyces cerevisiae“. Proceedings of the National Academy of Sciences 116, Nr. 39 (29.08.2019): 19415–20. http://dx.doi.org/10.1073/pnas.1900287116.

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Biobased C4-dicarboxylic acids are attractive sustainable precursors for polymers and other materials. Commercial scale production of these acids at high titers requires efficient secretion by cell factories. In this study, we characterized 7 dicarboxylic acid transporters in Xenopus oocytes and in Saccharomyces cerevisiae engineered for dicarboxylic acid production. Among the tested transporters, the Mae1(p) from Schizosaccharomyces pombe had the highest activity toward succinic, malic, and fumaric acids and resulted in 3-, 8-, and 5-fold titer increases, respectively, in S. cerevisiae, while not affecting growth, which was in contrast to the tested transporters from the tellurite-resistance/dicarboxylate transporter (TDT) family or the Na+ coupled divalent anion–sodium symporter family. Similar to SpMae1(p), its homolog in Aspergillus carbonarius, AcDct(p), increased the malate titer 12-fold without affecting the growth. Phylogenetic and protein motif analyses mapped SpMae1(p) and AcDct(p) into the voltage-dependent slow-anion channel transporter (SLAC1) clade of transporters, which also include plant Slac1(p) transporters involved in stomata closure. The conserved phenylalanine residue F329 closing the transport pore of SpMae1(p) is essential for the transporter activity. The voltage-dependent SLAC1 transporters do not use proton or Na+ motive force and are, thus, less energetically expensive than the majority of other dicarboxylic acid transporters. Such transporters present a tremendous advantage for organic acid production via fermentation allowing a higher overall product yield.

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Singh, Puspendra, Harkesh B. Singh und Ray J. Butcher. „Synthesis and characterization of selenium(I/II) and tellurium(IV) derivatives of amino acids“. Journal of Organometallic Chemistry 876 (Dezember 2018): 1–9. http://dx.doi.org/10.1016/j.jorganchem.2018.08.028.

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22

Zhang, Zhen Yu, Bo Wang und Ya Xing Song. „Chemical Mechanical Polishing of Soft-Brittle Cadmium Zinc Telluride Wafers Using a Developed Environment-Friendly Solution“. Advanced Materials Research 1017 (September 2014): 720–25. http://dx.doi.org/10.4028/www.scientific.net/amr.1017.720.

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A novel chemical mechanical polishing (CMP) solution was developed. The CMP solution developed consisted of mainly silica, hydrogen peroxide, and malic acid. CMP solution is environment-friendly, which is different from those used in conventional CMP, consisting of acids or organic solvents. Fixed abrasive waterproof paper of alumina with mesh size of 3000 was used as lapping tool, to avoid embedding of free abrasives on soft cadmium zinc telluride (CdZnTe or CZT) surfaces employed in traditional lapping processes. The diameter of silica was varied from several tens of nanometers to 100 nanometers. Surface roughness Ra, and PV achieved using fixed abrasive lapping and developed CMP solution are 0.6 nm and 6.3 nm, respectively. The polished CZT surface was cleaned by deionized water and dried using compressed air, to avoid damages induced by conventional physical wiping and ultrasonic cleaning on soft-brittle CZT wafers.

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Zalenkiene, Skirma, Judita Sukyte, Remigijus Ivanauskas und Vitalijus Janickis. „Selenopentathionic and Telluropentathionic Acids as Precursors for Formation of Semiconducting Layers on the Surface of Polyamide“. International Journal of Photoenergy 2007 (2007): 1–7. http://dx.doi.org/10.1155/2007/72497.

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The layers of copper chalcogenides, which were formed on the surface of semihydrophilic polymer—polyamide 6 (PA) using monoselenopentathionicH2SeS4O6and monotelluropentathionicH2TeS4O6acids as precursors of chalcogens, were characterized. Fourier transform infrared (FT-IR) and UV spectroscopy were used to monitor the effect of chalcogens on the changes in structure of PA corresponding to the concentration of the precursor's solution and an exposure time. The IR spectra of modified PA were completely different from that of the initial PA. Further interaction of chalcogenized PA with copper (II/I) salt solution leads to the formation ofCuxS,CuxSe,CuxTe,and mixed –CuxS–CuySeandCuxS–CuyTelayers which have different electric transport properties. The surface properties of PA after treatment are studied using AFM and XRD. The electrical resistances of layers with various composition formed over a wide concentration range 0.01–0.5mol⋅dm−3of precursor's solution were measured. Variation in the conductivity of layers of Cu–Se–S and Cu–Te–S on the surface of PA shows an evident increase with the increasing of the mass fraction of selenium or tellurium.

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Drake, John E., Layla N. Khasrou, Anil G. Mislankar und Raju Ratnani. „Synthesis, spectroscopic, and structural studies of dimethyltellurium(IV) alkylene and diphenyl dithiophosphates. Crystal structures of and“. Canadian Journal of Chemistry 72, Nr. 5 (01.05.1994): 1328–37. http://dx.doi.org/10.1139/v94-165.

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Dimethyltellurium alkylene dithiophosphates of the type [Formula: see text] where G = —CMe2CMe2—, —CHMeCHMe—, —CH2CMe2CH2—, and —CH2CEt2CH2—, have been synthesized in 80–90% yields by reaction of the corresponding sodium or ammonium salts of the appropriate dithiophosphoric acids with dimethyltellurium dichloride in toluene. Me2Te[S2P(OPh)2]2 was also prepared in a similar fashion. The compounds have been characterised by elemental analyses and 1H, 13C, 31P, and 125Te NMR, infrared and Raman spectroscopy. The crystal structures of [Formula: see text] and [Formula: see text] were determined. [Formula: see text]1, crystallizes in space group P21/c (No. 14) with the cell parameters a = 12.707(3) Å, b = 11.482(2) Å, c = 16.782(2) Å, β = 98.00(1)°, V = 2424(1) Å3, Z = 4, R = 0.0399, Rw = 0.0343. [Formula: see text]4, crystallizes in space group [Formula: see text] (No. 2) with the cell parameters a = 12.580(3) Å, b = 13.313(3) Å, c = 8.206(1) Å, α = 91.28(2)°, β = 104.94(2)°, γ = 78.52(2)°, V = 1301(1) Å3, Z = 2, R = 0.0364, Rw = 0.0295. The immediate environment about tellurium in both molecules is that of the saw-horse structure typical of tellurium(IV) compounds with the two methyl groups equatorial and one sulfur atom from each dithiophosphate group occupying the axial positions. The consideration of the second sulfur atom as part of the coordinating sphere is discussed in terms of a modification of Pauling's approach to partial bond orders. The 1H NMR spectra suggest that these dithiophosphates may be fluxional in solution and/or that there is rapid exchange of the sulfur atoms.

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He, Zhubing, Shu-Hong Yu und Jiping Zhu. „Amino Acids Controlled Growth of Shuttle-Like Scrolled Tellurium Nanotubes and Nanowires with Sharp Tips“. Chemistry of Materials 17, Nr. 11 (Mai 2005): 2785–88. http://dx.doi.org/10.1021/cm0503228.

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KUMAR, A., und D. C. DITTMER. „ChemInform Abstract: Synthesis of Intermediates for the Lactone Moiety of Mevinic Acids via Tellurium Chemistry.“ ChemInform 26, Nr. 11 (18.08.2010): no. http://dx.doi.org/10.1002/chin.199511294.

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Bassan, Jay, Lisa M. Willis, Ravi N. Vellanki, Alan Nguyen, Landon J. Edgar, Bradly G. Wouters und Mark Nitz. „TePhe, a tellurium-containing phenylalanine mimic, allows monitoring of protein synthesis in vivo with mass cytometry“. Proceedings of the National Academy of Sciences 116, Nr. 17 (10.04.2019): 8155–60. http://dx.doi.org/10.1073/pnas.1821151116.

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Protein synthesis is central to maintaining cellular homeostasis and its study is critical to understanding the function and dysfunction of eukaryotic systems. Here we report L-2-tellurienylalanine (TePhe) as a noncanonical amino acid for direct measurement of protein synthesis. TePhe is synthetically accessible, nontoxic, stable under biological conditions, and the tellurium atom allows its direct detection with mass cytometry, without postexperiment labeling. TePhe labeling is competitive with phenylalanine but not other large and aromatic amino acids, demonstrating its molecular specificity as a phenylalanine mimic; labeling is also abrogated in vitro and in vivo by the protein synthesis inhibitor cycloheximide, validating TePhe as a translation reporter. In vivo, imaging mass cytometry with TePhe visualizes translation dynamics in the mouse gut, brain, and tumor. The strong performance of TePhe as a probe for protein synthesis, coupled with the operational simplicity of its use, suggests TePhe could become a broadly applied molecule for measuring translation in vitro and in vivo.

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Langlois, P., S. Bourassa, G. G. Poirier und C. Beaulieu. „Identification of Streptomyces coelicolor Proteins That Are Differentially Expressed in the Presence of Plant Material“. Applied and Environmental Microbiology 69, Nr. 4 (April 2003): 1884–89. http://dx.doi.org/10.1128/aem.69.4.1884-1889.2003.

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ABSTRACT Streptomyces coelicolor and Lemna minor were used as a model to study the modulation of bacterial gene expression during plant-streptomycete interactions. S. coelicolor was grown in minimal medium with and without L. minor fronds. Bacterial proteomes were analyzed by two-dimensional gel electrophoresis, and a comparison of the two culture conditions resulted in identification of 31 proteins that were induced or repressed by the presence of plant material. One-half of these proteins were identified by peptide mass fingerprinting by using matrix-assisted laser desorption ionization-time of flight mass spectrometry. The induced proteins were involved in energetic metabolism (glycolysis, pentose phosphate pathway, oxidative phosphorylation), protein synthesis, degradation of amino acids, alkenes, or cellulose, tellurite resistance, and growth under general physiological or oxidative stress conditions. The repressed proteins were proteins synthesized under starvation stress conditions. These results suggest that root exudates provide additional carbon sources to the bacteria and that physiological adaptations are required for efficient bacterial growth in the presence of plants.

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Edwina, Uzunuigbe O., Ayabei Kiplagat, Nicole R. S. Sibuyi, Mervin Meyer, Abidemi Paul Kappo und Martin O. Onani. „Synthesis and cytotoxic evaluation of gum arabic surface modified cadmium telluride quantum dots“. Materials Express 10, Nr. 5 (01.05.2020): 611–19. http://dx.doi.org/10.1166/mex.2020.1675.

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Water-soluble cadmium telluride (CdTe) quantum dots (QDs) were capped with gum Arabic (GA) is a non-toxic, water-soluble glycoprotein polymer commonly used in the food and pharmaceutical industries. The GA was used to stabilise cadmium telluride quantum dots (GA-QDs) and provides functional groups for other molecules such as nucleic acids, peptides and antibodies to be attached to the QDs for biological and biomedical appli- cations. In this study, the GA was used to cap and stabilise QDs using two different methods. These QDs were characterised using Ultraviolet-visible (UV-vis) and Photoluminescence (PL) spectroscopy, X-powder ray diffraction (XRD), High-resolution transmission electron microscopy, zeta potential and particle size distribu- tions. Cytotoxicity of these QDs was also investigated using four different human cell lines; HeLa, MCF-7, PC-3 and U87 cancer cells. The QDs-MPA was capped with 3-mercaptopropionic acid, QDs-GA2 was stabilized and capped with GA at 60 °C for two hours, and QDs-GA12 was stabilized and capped with GA for twelve hours at room temperature (25 °C) with continuous stirring; These QDs were found to be highly luminescent with PL values of 675 nm, 678 nm and 677 nm respectively. The average polydispersity index (PDI) were 0.36 ± 0.02, 0.27 ± 0.02, 0.35 ± 0.01 for QDs-MPA, QDs-GA2 and QDs-GA12, respectively. The average particles size from HRTEM, XRD and hydrodynamic size showed that the QDs-GA have bigger particles sizes; (56.12 nm ± 1.14), (68.69 nm ± 2.08) and (77.85 nm ± 1.69) for QDs-MPA, QD-GA2 and QD-GA12 respectively. Cytotoxicity studies of these QDs were carried out using WST-1 cell proliferation assay on four different tumour cell line. The results showed that these cells were over 50 per cent viable and the QDs-GA capped had higher cell percentage viability.

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Amerkhanova, Sh, V. Aleksandrov, R. Shlyapov und A. Uali. „Physicochemical Particular Qualities of the Crystallization Process of Inorganic Heat-Storage Materials’ Melts“. Eurasian Chemico-Technological Journal 21, Nr. 3 (30.09.2019): 269. http://dx.doi.org/10.18321/ectj868.

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Investigations of the cluster-coagulation model for some inorganic substances and mixtures of sodium thiosulfate with salts of elements (VI) of A, B groups have been carried out. The doping of sodium thiosulfate pentahydrate with sodium selenate, tellurate, molybdate and tungstate has been carried out. The thermodynamic parameters of associate formation processes between sodium thiosulfate and salts formed from oxygen-containing acids of selenium, tellurium, molybdenum and tungsten have been calculated. The amount of heat introduced by the modifier (selenate, tellurate, molybdate and tungstate of sodium) into the total heat-accumulating effect of the mixture Na2S2O3∙5H2O – Na2XO4 (X – Se, Te, Mo or W) mixture has been calculated. The number of n-particle clusters and the diameter of clusters that are formed in the melt of the Na2S2O3∙5H2O – Na2XO4 mixture have been calculated. It is shown that special effects of systems based on mixtures consisting from sodium thiosulfate pentahydrate and salts of selenium, telluric, molybdenum, tungsten acids could be explained by more excessive tendency of these structures to the hydrate formation, associative stability and polymerization for the reason that rare elements’ ions in anionic form stabilize associates of sodium thiosulfate with water molecules that leads to growth the heat storage capacity. The scientific and practical significance of this research refers to the probability of prediction physicochemical properties of modified heat-accumulating materials based on the cluster-coagulation model.

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Wang, Min, Kai Ren und Lei Wang. „Iron-Catalyzed Ligand-Free Carbon-Selenium (or Tellurium) Coupling of Arylboronic Acids with Diselenides and Ditellurides“. Advanced Synthesis & Catalysis 351, Nr. 10 (Juli 2009): 1586–94. http://dx.doi.org/10.1002/adsc.200900095.

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Zhao, Xuan, Yu Wang, Yunli Da, Xinxia Wang, Tingting Wang, Mingquan Xu, Xiaoyun He et al. „Selective electrochemical production of hydrogen peroxide at zigzag edges of exfoliated molybdenum telluride nanoflakes“. National Science Review 7, Nr. 8 (25.04.2020): 1360–66. http://dx.doi.org/10.1093/nsr/nwaa084.

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Abstract The two-electron reduction of molecular oxygen represents an effective strategy to enable the green, mild and on-demand synthesis of hydrogen peroxide. Its practical viability, however, hinges on the development of advanced electrocatalysts, preferably composed of non-precious elements, to selectively expedite this reaction, particularly in acidic medium. Our study here introduces 2H-MoTe2 for the first time as the efficient non-precious-metal-based electrocatalyst for the electrochemical production of hydrogen peroxide in acids. We show that exfoliated 2H-MoTe2 nanoflakes have high activity (onset overpotential ∼140 mV and large mass activity of 27 A g−1 at 0.4 V versus reversible hydrogen electrode), great selectivity (H2O2 percentage up to 93%) and decent stability in 0.5 M H2SO4. Theoretical simulations evidence that the high activity and selectivity of 2H-MoTe2 arise from the proper binding energies of HOO* and O* at its zigzag edges that jointly favor the two-electron reduction instead of the four-electron reduction of molecular oxygen.

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Arivarasan, Ayyaswamy, Sasikala Ganapathy und Ramasamy Jayavel. „Fabrication of Highly Fluorescent Cadmium Based Aqueous Phase Colloidal Quantum Dots for Solar Cell Applications“. Advanced Materials Research 584 (Oktober 2012): 313–18. http://dx.doi.org/10.4028/www.scientific.net/amr.584.313.

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Highly fluorescent Cadmium based II-VI CQD’s plays a vital role in third generation photovoltaic’s design. In this paper, a novel approach for rapid synthesis of two different high quality cadmium based CQD’s in aqueous phase was presented and the optical stability and the structural properties of those materials were studied out. In this work Tellurium composed CQD’s along with cadmium were prepared by colloidal route. In the above procedure Thio Glycolic Acid (TGA) as well as Mercapto succinic acids (MSA) was used as the capping agents. All these procedures were carried out in aqueous medium at air atmosphere. The size dependent band gaps of the prepared quantum dots were determined from UV-Vis spectra and compared with the other one. The fluorescent properties of CdTe CQDs were investigated by using fluorescence spectra. The surface and structural morphologies were determined by using HRSEM and X-ray diffraction studies. The formation of CdTe quantum dots and the capping effect of the thiol group were investigated from EDAX and FTIR analysis.

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MA, KAI-GUO, JIN-YI BAI, TAN FANG und HAI-QING GUO. „EFFECT OF THE STRUCTURE OF ISOMERS OF MERCAPTOVALERIC ACID ON OPTICAL PROPERTIES OF CdTe QUANTUM DOTS“. Nano 08, Nr. 05 (18.08.2013): 1350049. http://dx.doi.org/10.1142/s1793292013500495.

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4-Mercaptovaleric acid (4MVA) and 3-mercaptovaleric acid (3MVA), two branched isomers of 5-mercaptovaleric acid (MVA), were designed and synthesized. They were used as capping agents in the aqueous synthesis of CdTe quantum dots (QDs) by a modified hydrothermal method with sodium tellurite as Te source. Compared with MVA- CdTe , either 4MVA-QDs or 3MVA-QDs exhibited higher fluorescent quantum yield (QY) and sharper absorption peak, which confirmed the superiority of using branched mercapto acids in the aqueous synthesis of QDs for improved optical properties. The fluorescence of QDs capped with 4MVA was higher than that of QDs capped with 4-mercaptobutyric acid (MBA) but lower than that of QDs capped with 3-mercaptobutyric acid (3MBA), which further confirmed the advantage of designing methyl side group rather than methylene group in the main chain for desired optical properties. However, the lower fluorescence, less sharp absorption peak and faster growth rate of 3MVA-QDs than that of 3MBA-QDs indicated adverse effect of side group on the aqueous synthesis of QDs if the size of side group is very bulky. Our results are helpful for selecting and designing appropriate capping agents for QDs with excellent properties.

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Pedro, Juana, Jorge Stripekis, Adrián Bonivardi und Mabel Tudino. „Thermal stabilization of tellurium in mineral acids solutions: Use of permanent modifiers for its determination in sulfur by GFAAS“. Talanta 69, Nr. 1 (15.03.2006): 199–203. http://dx.doi.org/10.1016/j.talanta.2005.09.027.

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Yang, Mengrui, und Tatsuya Fujino. „Quantitative Analysis of Free Fatty Acids in Human Serum Using Biexciton Auger Recombination in Cadmium Telluride Nanoparticles Loaded on Zeolite“. Analytical Chemistry 86, Nr. 19 (26.09.2014): 9563–69. http://dx.doi.org/10.1021/ac5018869.

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Altynnikova, E. E., V. A. Grabel'nykh, N. V. Russavskaya, L. M. Sinegovskaya, Ye N. Abdikalykov, A. M. Nalibayeva, G. K. Bishimbayeva und I. B. Rozentsveig. „The effect of the nature of the сhalcogen atom on the extraction and adsorption characteristics of chalcogen-containing oligomers based on chlorex“. Proceedings of Universities. Applied Chemistry and Biotechnology 11, Nr. 1 (06.04.2021): 6–15. http://dx.doi.org/10.21285/2227-2925-2021-11-1-6-15.

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The extraction and adsorption characteristics of chalcogen-containing oligomers derived from chlorex and elemental chalcogens in the hydrazine hydrate–base systems were studied. Sulphur- and selenium-containing oligomers synthesised in hydrazine hydrate–monoethanolamine systems are soluble in organic solvents. The as-obtained solutions are capable of extracting the following ions from water solutions: Hg2+, Cd2+, Zn2+, Pb2+, Cu2+ and Ni2+. Oligomers synthesised in the hydrazine hydrate–water–KOH system (sulphur- and selenium-containing oligomers) and a tellurium-containing oligomer obtained in the hydrazine hydrate–KOH system were used as adsorbents. It was assumed that the extraction and adsorption of metal ions by chalcogen-containing oligomers is carried out through the formation of complexes in which the chalcogen atoms act as ligands. The effect of the nature of chalcogen atoms on the possibility of forming complexes, i.e. on the extraction and adsorption properties of the oligomers used, was considered using the theory of hard and soft acids and bases (HSAB). According to this theory, the cations Hg2+ and Cd2+ belong to soft acids, while the cations Zn2+, Pb2+, Cu2+ and Ni2+ belong to acids of intermediate hardness. Chalcogen atoms are classified as soft bases. The conducted experiment showed that Hg2+ and Cd2+ ions are easily extracted and adsorbed by all the oligomers used, while the intermediate-hardness cations most easily interact with the sulphur-containing oligomers. The formation of oligomer–metal complexes was confirmed by analysing IR and 77Se NMR spectra recorded for sulphur- and selenium-containing oligomers before and after the extraction. The recorded IR spectra contained obvious changes in the nature of the absorption bands due to the stretching vibrations of the C–S and C–Se bonds. An additional signal of de-screened selenium nuclei was observed in the 77Se NMR spectrum. An insignificant change in the nature of the IR spectra in the region of stretching C–O vibrations indicated a weak participation of oxygen in the formation of complexes. It can be assumed that the role of oxygen in maintaining the high rates of extraction and adsorption is associated with an increase in the flexibility of macromolecules, which ensures a more favourable geometry for complex formation.

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Vornhagen, Jay, Christine M. Bassis, Srividya Ramakrishnan, Robert Hein, Sophia Mason, Yehudit Bergman, Nicole Sunshine et al. „A plasmid locus associated with Klebsiella clinical infections encodes a microbiome-dependent gut fitness factor“. PLOS Pathogens 17, Nr. 4 (30.04.2021): e1009537. http://dx.doi.org/10.1371/journal.ppat.1009537.

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Klebsiella pneumoniae (Kp) is an important cause of healthcare-associated infections, which increases patient morbidity, mortality, and hospitalization costs. Gut colonization by Kp is consistently associated with subsequent Kp disease, and patients are predominantly infected with their colonizing strain. Our previous comparative genomics study, between disease-causing and asymptomatically colonizing Kp isolates, identified a plasmid-encoded tellurite (TeO3-2)-resistance (ter) operon as strongly associated with infection. However, TeO3-2 is extremely rare and toxic to humans. Thus, we used a multidisciplinary approach to determine the biological link between ter and Kp infection. First, we used a genomic and bioinformatic approach to extensively characterize Kp plasmids encoding the ter locus. These plasmids displayed substantial variation in plasmid incompatibility type and gene content. Moreover, the ter operon was genetically independent of other plasmid-encoded virulence and antibiotic resistance loci, both in our original patient cohort and in a large set (n = 88) of publicly available ter operon-encoding Kp plasmids, indicating that the ter operon is likely playing a direct, but yet undescribed role in Kp disease. Next, we employed multiple mouse models of infection and colonization to show that 1) the ter operon is dispensable during bacteremia, 2) the ter operon enhances fitness in the gut, 3) this phenotype is dependent on the colony of origin of mice, and 4) antibiotic disruption of the gut microbiota eliminates the requirement for ter. Furthermore, using 16S rRNA gene sequencing, we show that the ter operon enhances Kp fitness in the gut in the presence of specific indigenous microbiota, including those predicted to produce short chain fatty acids. Finally, administration of exogenous short-chain fatty acids in our mouse model of colonization was sufficient to reduce fitness of a ter mutant. These findings indicate that the ter operon, strongly associated with human infection, encodes factors that resist stress induced by the indigenous gut microbiota during colonization. This work represents a substantial advancement in our molecular understanding of Kp pathogenesis and gut colonization, directly relevant to Kp disease in healthcare settings.

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von Eiff, Christof, Peter McNamara, Karsten Becker, Donna Bates, Xiang-He Lei, Michael Ziman, Barry R. Bochner, Georg Peters und Richard A. Proctor. „Phenotype Microarray Profiling of Staphylococcus aureus menD and hemB Mutants with the Small-Colony-Variant Phenotype“. Journal of Bacteriology 188, Nr. 2 (15.01.2006): 687–93. http://dx.doi.org/10.1128/jb.188.2.687-693.2006.

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ABSTRACT Standard biochemical tests have revealed that hemin and menadione auxotrophic Staphylococcus aureus small-colony variants (SCVs) exhibit multiple phenotypic changes. To provide a more complete analysis of the SCV phenotype, two genetically defined mutants with a stable SCV phenotype were comprehensively tested. These mutants, generated via mutations in menD or hemB that yielded menadione and hemin auxotrophs, were subjected to phenotype microarray (PM) analysis of over 1,500 phenotypes (including utilization of different carbon, nitrogen, phosphate, and sulfur sources; growth stimulation or inhibition by amino acids and other nutrients, osmolytes, and metabolic inhibitors; and susceptibility to antibiotics). Compared to parent strain COL, the hemB mutant was defective in utilization of a variety of carbon sources, including Krebs cycle intermediates and compounds that ultimately generate ATP via electron transport. The phenotype of the menD mutant was similar to that of the hemB mutant, but the defects in carbon metabolism were more pronounced than those seen with the hemB mutant. In both mutant strains, hexose phosphates and other carbohydrates that provide ATP in the absence of electron transport stimulated growth. Other phenotypes of SCV mutants, such as hypersensitivity to sodium selenite, sodium tellurite, and sodium nitrite, were also uncovered by the PM analysis. Key results of the PM analysis were confirmed in independent growth studies and by using Etest strips for susceptibility testing. PM technology is a new and efficient technology for assessing cellular phenotypes in S. aureus.

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Bachvarova-Nedelcheva, Albena, Reni Iordanova, Angelina Stoyanova, Nelly Georgieva, Veronica Nemska und Tsvetelina Foteva. „Effect of B2O3 on the Structure, Properties and Antibacterial Abilities of Sol-Gel-Derived TiO2/TeO2/B2O3 Powders“. Materials 16, Nr. 19 (25.09.2023): 6400. http://dx.doi.org/10.3390/ma16196400.

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This paper studies the influence of B2O3 on the structure, properties and antibacterial abilities of sol-gel-derived TiO2/TeO2/B2O3 powders. Titanium(IV) butoxide, telluric(VI) acid and boric acid were used as precursors. Differences were observed in the degree of decomposition of Ti butoxide in the presence of H3BO3 and H6TeO6 acids. The phase transformations of the obtained gels in the temperature range of 200–700 °C were investigated by XRD. Composite materials containing an amorphous phase and different crystalline phases (metallic Te, α-TeO2, anatase, rutile and TiTe3O8) were prepared. Heating at 400 °C indicated a crystalline-to-amorphous-phase ratio of approximately 3:1. The scanning electron microscopy (SEM) analysis showed the preparation of plate-like TiO2 nanoparticles. The IR results showed that the short-range order of the amorphous phases that are part of the composite materials consists of TiO6, BO3, BO4 and TeO4 structural units. Free B2O3 was not detected in the investigated compositions which could be related to the better connectivity between the building units as compared to binary TiO2/B2O3 compositions. The UV-Vis spectra of the investigated gels exhibited a red shift of the cut-off due to the presence of boron and tellurium units. The binary sample achieved the maximum photodegradation efficiency (94%) toward Malachite green dye under UV irradiation, whereas the ternary sample photoactivity was very low. The compositions exhibited promising antibacterial activity against E. coli NBIMCC K12 407.

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Xu, Peipei, Baoan Chen, Jingyuan Li und Xuemei Wang. „Gambogic Acid Combined With CdTe QDs For Leukemia Cancer Cells Inhibition and Their Bio-Safety For Rat Brain“. Blood 122, Nr. 21 (15.11.2013): 5028. http://dx.doi.org/10.1182/blood.v122.21.5028.5028.

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Abstract The development of new anticancer agents typically involves long research cycles, high cost and low efficiency and so on. There has been a growing public interest in the use of complementary and alternative medicine for cancer treatment and drug discovery. The emergence of nanotechnology and nanomaterials has greatly stimulated research in drug delivery and optimization. As a good fluorescence probe and simultaneously as potential drug carrier, Cadmium-Tellurium quantum dots (CdTe QDs) can optimize the use and a new potential therapy method of some drug-active compounds. Based on these considerations, we have explored the possibility to connect cysteamine (Cys) modified CdTe QDs (Cys-CdTe) to gambogic acid (GA). These functional QDs were studied for multi-functional drug delivery to investigate the synergetic effect of these composites between GA and QDs for human leukemia caner cells K562 and their drug-resistant cell line K562/A02 in vitro. Also the neurotoxicity of different drug systems for Sprague Dawley (SD) rat brain was analyzed by in vivo real-time microdialysis. The nanocomposites of GA loaded CdTe QDs were prepared and the drug releasing of GA-CdTe nanocomposites was performed at the medium of pH 6.0 and 7.4 in vitro. The cytotoxicity of GA and the nanocomposites for K562 and K562/A02 cells was studied by MTT, cell morphology, and flow cytometry. The labeling and imaging of CdTe QDs and the nanocomposites for cancer cells was performed by laser confocal fluorescence microscopy. Different drug systems were respectively injected into SD rat by vena caudalis and cerebrospinal fluid was collected by microdialysis in vivo. The neurotoxicity of different drug systems for rat brain was investigated by the changes of amino acid content in the cerebrospinal fluid. The Cys modified CdTe QDs showed the good fluorescence characteristics, with the wide excitation spectrum and narrow emission spectrum. The CdTe QDs could label in human leukemia cancer cells not only for K562 but also K562/A02 , which had the potential application in the cell imaging. Following the electrostatic attraction, surface adsorption et al, these CdTe QDs had the good capability of drug delivery with the high drug-loading and envelopment capacity. Also these GA-CdTe nanocomposites showed the pH sensitivity for the drug release and improved the drug's un-dissolvability. The GA-CdTe nanocomposites also had the fluorescence characteristics for labeling the different kinds of leukemia cancer cells. Gambogic acid play an important role in cancer therapy and also showed the sensitivity for the multidrug resistance (MDR) of K562/A02 cells in this study. The results indicated that GA-CdTe nanocomposites could significantly enhance the drug accumulation to improve the cytotoxicity and considerably overcome the multidrug resistance. GA-CdTe nanocomposites induced the arrest of G0/G1 phase to promote the cells apoptosis. The combination between GA and CdTe QDs can optimize the new potential therapeutic method for GA with the real time labeling and tracing during the disease therapy. The neurotoxicity of GA and GA-CdTe nanocomposites for rat brain was firstly explored by using the microdialysis in vivo. The results indicated that GA had the serious neurotoxicity through the concentration changes of amino acids for the rat brain. The concentration of some excitatory amino acids was remarkably increased. For the GA-CdTe nanocomposites based on CdTe QDs, the side effect of GA was visibly cut down, and the time to cause the neurotoxicity was apparently shortened. These nanocomposites own the better biocompatibility and bio-safety for the relevant cancer treatment in vitro and in vivo. This raises the promising possibility of the application of these fluorescent nanocomposites based on CdTe QDs for the target cancer therapy. The combination of GA with Cys-CdTe QDs can optimize the use and new potential multi-mode therapy of cancers. This may shed new light to exploit the potential application of the active compounds from Traditional Chinese Medicine (TCM). Disclosures: No relevant conflicts of interest to declare.

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Delgado, Guillermo. „Preface“. Pure and Applied Chemistry 79, Nr. 2 (01.01.2007): iv. http://dx.doi.org/10.1351/pac20077902iv.

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Organic synthesis continues to grow and develop impressively in response to new research challenges at the boundaries of structural complexity, while playing a central role in the industrial activities and applications of the chemical sciences. The International Conferences on Organic Synthesis (ICOS), which have been organized biennially around the world since 1976 under IUPAC sponsorship, faithfully reflect this growth and development.The 16th event in this series (ICOS-16) was held in Mérida, México, from 11 to 15 June 2006. The scientific program included 22 plenary and invited speakers, as well as 36 experts who participated in symposia on medicinal chemistry, organocatalysis, enantioselective synthesis of β-amino acids, organolithium compounds in organic synthesis, organic selenium and tellurium compounds in organic synthesis, and applications of microwaves in organic synthesis. In addition, almost 300 posters covering all aspects of modern organic synthesis were displayed by scientists and research scholars. The strong Latin American participation in this feature of the program, followed by those of European, North American, and Asian delegates, attested to the growing contribution of this region to chemical research in organic synthesis. Overall, the scientific program offered comprehensive and fruitful coverage of organic synthesis from a variety of different perspectives.The Mexican Academy of Sciences and the Mexican Chemical Society (celebrating its 50th Anniversary) featured as cosponsors of ICOS-16 together with IUPAC. This was the second occasion that an IUPAC-sponsored conference has been held in Mexico, the first being the 6th International Symposium on Natural Products Chemistry in Mexico City, in 1969. ICOS-16 attracted almost 500 delegates from 40 countries, mainly those of Latin America, a gratifyingly high proportion of whom were younger scientists.This issue of Pure and Applied Chemistry contains a representative selection of papers based upon lectures delivered at ICOS-16. The theme of synthesis of natural products was covered by M. Brimble (New Zealand), L. C. Dias (Brazil), and C. Gennari (Italy). Different aspects on methodology and control of chemical reactivity were presented by J. Tamariz (Mexico), S. F. Martin (USA), S. Ma (China), and Ph. Renaud (Switzerland). Organic synthesis using phosphorous was covered by R. Réau (France) and C. Nájera (Spain). The broad topic of catalysis was presented by S. Kobayashi (Japan) and C. Crudden (USA). New insights on synthesis using epoxides and aziridines were disclosed by D. Hodgson (UK) and F. McDonald (USA).Organic synthesis is a fascinating field of chemistry that has often been compared with art. The control of regio-, stereo-, and site selectivity demands deep insight into chemical reactivity as well as knowledge of new and old methodology and catalysis, and the ability to combine these creatively in sustainable processes in order to achieve specific objectives. Despite remarkable progress during recent years, efficient synthesis of specific organic compounds with tailored activities and properties will continue to challenge future generations of chemists. Further progress of organic synthesis will be covered during the next conference in this series (ICOS-17), which will take place in Korea during 2008.Thanks are due to members of the ICOS-16 Committees, to all participants, and to authors contributing to this issue.Guillermo DelgadoConference Editor

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Valkovicova, Lenka, Danka Valkova, Silvia Vavrova, Olga Alekhina, Vinh Hoang, Margareta Jezna und Jan Turna. „The role of TerW protein in the tellurite resistance of uropathogenic Escherichia coli“. Biologia 66, Nr. 4 (01.01.2011). http://dx.doi.org/10.2478/s11756-011-0075-5.

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AbstractThe ter operon, which is found on a large conjugative plasmid, pTE53, from the uropathogenic strain Escherichia coli KL53, mediates heavy metal ion resistance to tellurium compounds. Here we present the function of the terW gene, which is transcribed from its own promoter in the opposite direction to the terZABCDE loci and encodes a protein of 155 amino acids. A TerW protein containing an N-terminal His-tag was overexpressed, purified and analysed for the in vitro DNA-binding. Green fluorescent protein fusions, a fluorimetric assay, nonradioactive gel retardation and capillary electrophoresis footprinting were used to examine the interaction between the bioinformatically-predicted DNA-binding region and TerW. Here we show that TerW binds specifically to the potential promoter region of the terZABCDE genes, which are responsible for the tellurite resistance of the Escherichia coli host cells. Our results suggest that the transcriptional regulation of ter genes is operon-like.

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Blödorn, Gustavo B., Manoela Sacramento, Eduardo Martarelo Andia Sandagorda, Ariana S. Lima, Joel S. Reis, Márcio Santos Silva und Diego Alves. „Silver-Catalyzed Synthesis of Symmetrical Diaryl Tellurides from Arylboronic Acids and Tellurium“. New Journal of Chemistry, 2022. http://dx.doi.org/10.1039/d2nj04019k.

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tellurium through a simple methodology using silver catalysis. In contrast to other methodologies described in the literature, this protocol takes advantage of using Te0 for the synthesis of tellurides, skipping...

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Ho, Peter C., Jin Wang und Ignacio Vargas-Baca. „Reagents that Contain Se-H or Te-H Bonds“. Physical Sciences Reviews 4, Nr. 1 (14.09.2018). http://dx.doi.org/10.1515/psr-2017-0130.

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Abstract Species that contain bonds between hydrogen and selenium or tellurium have a characteristic high reactivity, which can be harnessed in the synthesis of valuable organic compounds. This overview includes the synthesis of dihydrides, alkali metal hydrochalcogenides, chalcogenols, chalcogenocarboxylic and chalcogenocarbamic acids, and their application in reactions of reduction, addition to unsaturated compounds, and nucleophilic substitution.

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Maltman, Chris, Steven B. Kuzyk, John A. Kyndt, George Lengyel und Vladimir Yurkov. „Shewanella metallivivens sp. nov., a deep-sea hydrothermal vent tube worm endobiont capable of dissimilatory anaerobic metalloid oxyanion reduction“. International Journal of Systematic and Evolutionary Microbiology 73, Nr. 7 (21.07.2023). http://dx.doi.org/10.1099/ijsem.0.005980.

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A polyphasic taxonomic study was carried out on a Gram-stain-negative and rod-shaped strain, ER-Te-42B-LightT, isolated from the tissue of a tube worm, Riftia pachyptila, collected near a deep-sea hydrothermal vent of the Juan de Fuca Ridge in the Pacific Ocean. This bacterium was capable of performing anaerobic respiration using tellurite, tellurate, selenite and orthovanadate as terminal electron acceptors. While facultatively anaerobic, it could aerobically resist tellurite, selenite and orthovanadate up to 2000, 7000 and 10000 µg ml−1, respectively, reducing each oxide to elemental forms. Nearly complete 16S rRNA gene sequence similarity related the strain to Shewanella , with 98.8 and 98.7 % similarity to Shewanella basaltis and Shewanella algicola , respectively. The dominant fatty acids were C16 : 0 and C16 : 1. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol and MK-7 was the predominant quinone. DNA G+C content was 42.5 mol%. Computation of average nucleotide identity and digital DNA–DNA hybridization values with the closest phylogenetic neighbours of ER-Te-42B-LightT revealed genetic divergence at the species level, which was further substantiated by differences in several physiological characteristics. Based on the obtained results, this bacterium was assigned to the genus Shewanella as a new species with the name Shewanella metallivivens sp. nov., type strain ER-Te-42B-LightT (=VKM B-3580T=DSM 113370T).

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Jung, K. W., und A. S. Nagle. „Acyclic and Cyclic Carbonic Acids and Esters, and Their Sulfur, Selenium, and Tellurium Analogues“. ChemInform 36, Nr. 38 (20.09.2005). http://dx.doi.org/10.1002/chin.200538257.

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Rossi, L. „Acyclic and Cyclic Carbamic Acids and Esters, and Their Sulfur, Selenium, Tellurium, and Phosphorus Analogues“. ChemInform 36, Nr. 38 (20.09.2005). http://dx.doi.org/10.1002/chin.200538256.

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Grimm, David, Nathan Guy, George Lengyel, Jonathan Franks und Chris Maltman. „Gordonia metallireducens sp. nov., a tellurite- and selenite-resistant bacterium isolated from the sediment of an acid mine drainage stream“. International Journal of Systematic and Evolutionary Microbiology 73, Nr. 11 (22.11.2023). http://dx.doi.org/10.1099/ijsem.0.006176.

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A polyphasic taxonomic study was carried out on strain TSed Te1T, isolated from sediment of a stream contaminated with acid drainage from a coal mine. The bacterium forms pink-pigmented colonies and has a rod–coccus growth cycle, which also includes some coryneform arrangements. This bacterium is capable of growing in the presence of up to 750 μg ml−1 tellurite and 5000 μg ml−1 selenite, reducing each to elemental form. Nearly complete 16S rRNA gene sequence analysis associated the strain with Gordonia , with 99.5 and 99.3 % similarity to Gordonia namibiensis and Gordonia rubripertincta , respectively. Computation of the average nucleotide identity and digital DNA–DNA hybridization comparisons with the closest phylogenetic neighbour of TSed Te1T revealed genetic differences at the species level, which were further substantiated by differences in several physiological characteristics. The dominant fatty acids were C16 : 0, C18 : 1, C16 : 1 and tuberculostearic acid. The DNA G+C content was 67.6 mol%. Major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside, while MK-9(H2) was the only menaquinone found. Mycolic acids of C56–C60 were present. Whole-cell hydrolysates contained meso-diaminopimelic acid along with arabinose and galactose as the major cell-wall sugars. On the basis of the results obtained in this study, the bacterium was assigned to the genus Gordonia and represents a new species with the name Gordonia metallireducens sp. nov. The type strain is TSed Te1T (=NRRL B-65678T=DSM 114093T).

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Kut, M., N. Korol, M. Onysko und V. Lendel. „IN SILICO STUDY OF PYRIMIDINARYLTELLURIDES AS POTENTIAL INHIBITORS OF PLASMODIUM FALCIPARUM“. Scientific Bulletin of the Uzhhorod University. Series «Chemistry» 49, Nr. 1 (02.10.2023). http://dx.doi.org/10.24144/2414-0260.2023.1.50-56.

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Malarial plasmodia are increasingly developing resistance to existing antimalarial drugs, posing a serious threat to successful treatment. Previous studies have demonstrated the inhibitory activity of compounds containing an exocyclic aryltellurium fragment against Plasmodium falciparum. This research focused on evaluating the inhibitory potential of fused pyrimidinaryl tellurides against falcipain-2 (FP-2), a crucial therapeutic target in the fight against malaria. Among the tested tellurides, 2-(((4-methoxyphenyl)thelanyl)methyl)-2,3-dihydro-5H-thiazolo[2,3-b]quinazolin-5-one demonstrated the most stable protein-ligand complex with the receptor 2GHU. The ligand exhibited a binding energy of -6.18 kcal/mol and an inhibition concentration of 29.74 μM. Notably, the ligand interacted with specific amino acids of the receptor, including HIS27, ASP23, TYR199, LYS184, and ALA21. Additionally, a 100 ns molecular dynamics study confirmed the stability of the falcipain-2 complex with this thiazoloquinazolinaryltellurtrichloride, further supporting the potential of compound 1. Importantly, the tested substance exhibited superior inhibitory capability against Plasmodium falciparum compared to antimalarial drugs such as mefloquine, primaquine, and chloroquine, making it a candidate for in vitro evaluation of antimalarial activity. Keywords: malaria; Plasmodium falciparum; telluride; Falcipain-2; 2GHU.

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