27 research outputs found
Preparation of cobalt titanates via co-precipitation while using industrial intermediates as titanium precursors
This paper reports on the results of cobalt titanates preparation by calcination of green bodies obtained by a co-precipitation method. For the investigations were used: as titanium sources, acidic solutions of titanyl sulfate and hydrous titanium dioxide, originating from the production process of titanium dioxide by sulfate method. The composition of the obtained materials was determined using titration methods. The calcined powders were characterized by X-ray diffraction method. It has been found that the obtained products are composed of cobalt methatitanate CoTiO3 or cobalt orthotitanate Co2TiO4 occurring as single phases, and also as cobalt titanates and titanium dioxide phase mixtures. The proposed method of proceeding can be used for the preparation of series of transition metals titanates, such as nickel, iron, zinc, copper and also aluminium titanates
Investigations of the thermal transformations of precipitated mixed transition metal hydroxides
Calculation of kinetic parameters from TG curve on the base of dehydration process of hydrous titanium dioxide
Enthalpy of solution and effect of temperature on activity coefficients in MSO4−H2SO4−H2O system
Relationship of bone mineral density with disease activity and functional ability in patients with ankylosing spondylitis: a cross-sectional study
In ankylosing spondylitis, inflammatory activity probably plays a key role in the pathophysiology of bone loss. The aim of the study was to investigate the relationship of bone mineral density (BMD) at the lumbar spine and hip region with some measures of disease activity and functional ability in patients with ankylosing spondylitis. In 80 patients with established ankylosing spondylitis, disease activity and functional ability were determined by C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI). Spinal pain and patient global health were assessed using horizontal visual analog scale. BMD was measured by dual-energy X-ray absorptiometry. There was a significant negative correlation of bone density T scores with acute-phase reactants (i.e., patients with lower T scores had higher level of CRP and ESR). That relationship was reflected more reliably at proximal femur sites than at the lumbar spine. There were also significant differences in ESR, BASDAI, BASFI, spinal pain and global health between three groups of patients according to WHO classification of osteoporosis (normal, osteopenic and osteoporotic). Significantly, more patients with osteopenia at the lumbar spine had lower BASDAI index than those with normal BMD (P = 0.030). Our results indicate an association of low BMD with high disease activity in patients with AS. Femoral BMD seems to be more associated with disease activity and functional ability than lumbar spine BMD