G Processing and characterization of CaTiO 3 perovskite ceramics
Calcium titanate (CaTiO3) ceramics with perovskite structure were produced by solid state reaction. Calcium carbonate (CaCO3) and titanium dioxide (TiO2) were mixed (in molar ratios 1/1 and 3/2), and the obtained mixtures were calcined at 1150 °C in successive thermal cycles. The obtained samples were characterized by differential thermal analysis, thermogravimetry, X-ray diffraction, measurement of particle size distribution and linear thermal shrinkage. XRD results indicated that the samples have perovskite CaTiO3 structure with small amount of secondary CaO and TiO2 phases, and their phase composition depends on the heat treatment conditions. The measured values of electrical resistivity were within the characteristic range of insulating materials and approach values corresponding to semiconducting ceramics.
Synthesis of perovskite CaTiO3 nanopowders with different morphologies by mechanical alloying without heat treatment
Mechanical alloying (MA) method is one of the methods used for large scale production of different nanopowders. In this study, calcium titanate (CaTiO3: CTO) nanoparticles have been synthesized via mechanical alloying (MA) without using heat treatment. The milled powders and CTO were characterized by XRD, SEM, and zetasizer. It is found that the CTO has a diameter of 30 - 70 nm with different morphologies. The results showed the minimum time of calcium titanate synthesis via mechanical alloying without heat treatment is 70 h that formed and the range of grain size (apparent size) using Williamson-Hall equation is 69 nm. 
 
   
 
 Key words: Mechanical alloying/activation, morphology, perovskite, CaTiO3.
Systemic juvenile rheumatoid arthritis complicated by two different renal lesions
Abstract. Systemic-onset juvenile rheumatoid arthritis (JRA) is a complex disease which affects many organ systems. Associated renal lesions are unusual, with the possible exception of amyloidosis. We describe a girl with systemic-onset JRA who developed first membranous nephropathy and then, 3.5 years later, a severe crescentic glomerulonephritis. The membranous lesion followed therapy with intravenous immune globulin, and the possibility that this intervention caused the renal disease must be considered. It appears that both of these lesions should be added to the list of possible complications of systemic-onset JRA.