Dielectric Properties Of Lead Potassium Lithium Niobate (Pb1,85K1,15Li0,15Nb5O15) With Tetragonal Tungsten Bronze (TTB) Type Structure

A new tungsten bronze ceramic oxide, Pb2-xK1+xLixNb5O15 (PKLN) (x =0.15) was prepared by high temperature solid-state reaction route. Structural and electrical properties are investigated using X-ray diffraction and dielectric measurements. Room temperature XRD pattern confirms the formation of the compound with an orthorhombic crystal system. The dielectric permittivity and the loss tangent of the sample have been measured in a frequency range 1Hz–1MHz and a temperature range 35–550 °C. Studies of dielectric properties show that the compound exhibits an anomaly at 425°C (usually called transition temperature).The electrical parameters of the material were studied using complex impedance spectroscopy showing that the compound exhibits non-Debye of relaxation process. In the paraelectric phase, activation energy was determined and the value is Eτ = 0.68 eV. The present ceramic is promising candidate for high dielectric constant and low loss dielectric ceramic.A new tungsten bronze ceramic oxide, Pb2-xK1+xLixNb5O15 (PKLN) (x =0.15) was prepared by high temperature solid-state reaction route. Structural and electrical properties are investigated using X-ray diffraction and dielectric measurements. Room temperature XRD pattern confirms the formation of the compound with an orthorhombic crystal system. The dielectric permittivity and the loss tangent of the sample have been measured in a frequency range 1Hz–1MHz and a temperature range 35–550 °C. Studies of dielectric properties show that the compound exhibits an anomaly at 425°C (usually called transition temperature).The electrical parameters of the material were studied using complex impedance spectroscopy showing that the compound exhibits non-Debye of relaxation process. In the paraelectric phase, activation energy was determined and the value is Eτ = 0.68 eV. The present ceramic is promising candidate for high dielectric constant and low loss dielectric ceramic

Cadmium accumulation and interactions with zinc, copper, and manganese, analysed by ICP-MS in a long-term Caco-2 TC7 cell model

The influence of long-term exposure to cadmium (Cd) on essential minerals was investigated using a Caco-2 TC7 cells and a multi-analytical tool: microwave digestion and inductively coupled plasma mass spectrometry. Intracellular levels, effects on cadmium accumulation, distribution, and reference concentration ranges of the following elements were determined: Na, Mg, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo, and Cd. Results showed that Caco-2 TC7 cells incubated long-term with cadmium concentrations ranging from 0 to 10 lmol Cd/l for 5 weeks exhibited a significant increase in cadmium accumulation. Furthermore, this accumulation was more marked in cells exposed long-term to cadmium compared with controls, and that this exposure resulted in a significant accumulation of copper and zinc but not of the other elements measured. Interactions of Cd with three elements: zinc, copper, and manganese were particularly studied. Exposed to 30 lmol/l of the element, manganese showed the highest inhibition and copper the lowest on cadmium intracellular accumulation but Zn, Cu, and Mn behave differently in terms of their mutual competition with Cd. Indeed, increasing cadmium in the culture medium resulted in a gradual and significant increase in the accumulation of zinc. There was a significant decrease in manganese from 5 lmol Cd/l exposure, and no variation was observed with copper. Abbreviation: AAS – Atomic absorption spectrometry; CRM– Certified reference material; PBS – Phosphate buffered saline without calcium and magnesium; DMEM – Dubelcco’s modified Eagle’s medium

Commission de patronage

Berthelot , Frémy , Troost L., Bouty , Philippon P. Commission de patronage. In: Rapport sur l'École pratique des hautes études, 1889-1892. 1889. p. 2

Commission de patronage

Berthelot , Desains Paul, Jamin , Frémy , Wurtz , Philippon P. Commission de patronage. In: Rapport sur l'École pratique des hautes études, 1876-1877. 1876. p. 7

Commission de patronage

Berthelot , Desains Paul, Jamin , Frémy , Wurtz , Philippon P. Commission de patronage . In: Rapport sur l'École pratique des hautes études, 1879-1880. 1879. p. 9

Commission de patronage

Berthelot , Desains Paul, Jamin , Frémy , Wurtz , Philippon P. Commission de patronage. In: Rapport sur l'École pratique des hautes études, 1875-1876. 1875. p. 7

Commission de patronage

Berthelot , Desains Paul, Jamin , Frémy , Wurtz , Philippon P. Commission de patronage. In: Rapport sur l'École pratique des hautes études, 1876-1877. 1876. p. 7

Commission de patronage

Berthelot , Desains Paul, Jamin , Frémy , Wurtz , Philippon P. Commission de patronage. In: Rapport sur l'École pratique des hautes études, 1881-1882. 1881. p. 9

Commission de patronage

Berthelot , Desains Paul, Frémy , Troost L., Philippon P., Jamin . Commission de patronage. In: Rapport sur l'École pratique des hautes études, 1884-1885. 1884. p. 9