Partial characterisation of enterocin KP produced by Enterococcus faecalis KP,a cheese isolate

Enterococcus faecalis KP, a bacteriocin‐producing strain, was identified using 16S rRNA gene sequence homology (99%). Enterocin KP from E. faecalis KP was sensitive to papain and ß‐mercaptoethanol, but resistant to trypsin, pepsin, lipase, catalase, α‐amylase, organic solvents, detergents, EDTA and heat treatment (90°C/30 min). It was active at a wide pH range (2.0–8.0) and produced at maximum level in de Mann Rogosa Sharpe broth at 32°C with an inoculum amount of 0.1–1.0% and an initial pH of 5.5–7.5. It was active against some Gram‐positive bacteria, including Listeria monocytogenes. It showed bactericidal activity against L. monocytogenes and its molecular weight was approximately 5.8 kDa.     

Synthesis and luminescence properties of BaTiO3:RE (RE = Gd3+, Dy3+, Tb3+, Lu3+) phosphors

Gd³⁺, Dy³⁺, Tb³⁺ and Lu³⁺ doped BaTiO₃-based phosphors were synthesized with modified solid-state technique at 1000 °C. The optimization of reaction conditions were carried out by thermogravimetry and differential thermal analysis methods (DTA/TG). The reaction products obtained in an air atmosphere were characterized by X-ray powder diffraction (XRD). Surface and elemental analyses were performed by using an SEM instrument. The excitation and emission spectra were recorded by photoluminescence spectrophotometer (PL). The thermoluminescence (TL) properties of BaTiO₃ samples doped with Gd³⁺, Dy³⁺, Tb³⁺ and Lu³⁺ were investigated.     

Synthesis, characterization and oxide ionic conductivity of β-type solid solution in bismuth oxide doped with ytterbium oxide binary system

In this study, after doping Yb₂O₃ substance to α -Bi₂O₃ substance in the range of 1% ≤ n ≤ 8% in a series of different mole ratios, heat treatment was performed by applying a cascade temperature rise in the range of 700–790 °C for 48 and 120 h and new phases were obtained in the (Bi₂O₃)_1???x (Yb₂O₃) _x system. After 48 h of heat treatment at 750 °C and 120 h of heat treatment at 790 °C, mixtures containing 1–8% mole Yb₂O₃ formed a tetragonal phase. With the help of XRD, crystal systems and lattice parameters of the solid solutions were obtained and their characterization was carried out. Thermal measurements were made by using a simultaneous DTA/TG system. The total conductivity (σ _T) in the β-Bi₂O₃ doped with Yb₂O₃ system was measured using four-probe d.c. method.     

Yellow phosphors doping with Gd3 + , Tb3 + and Lu3 + in MTiO3 (M = Mg and Sr) luminescence properties

This paper reports Gd^3?+?, Tb^3?+? and Lu^3?+? doped MTiO₃ (M = Mg and Sr)-based phosphors which were synthesized by the conventional solid-state reaction method, their crystal structures and luminescence properties were investigated. X-ray diffraction patterns (XRD) showed that phosphors sintered at 1000 °C for 2 h were the pure SrTiO₃ and MgTiO₃ phases. The optimization of reaction conditions was carried out by thermogravimetry and differential thermal analysis (DTA/TG) methods. Surface and elemental analyses were performed by using SEM instrument. The excitation and emission spectra were recorded by a photoluminescence spectrophotometer (PL). The thermoluminescence (TL) properties of MgTiO₃:RE (RE = Gd^3?+?, Tb^3?+?, Lu^3?+?) and SrTiO₃:RE (RE = Gd^3?+?, Tb^3?+?, Lu^3?+?) were investigated.