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.
FOTOLUMINESCÊNCIA E ADSORÇÃO DE CO 2 EM NANOPARTÍCULAS DE CaTiO 3 DOPADAS COM LANTÂNIO
Ca1-xLaxTiO3 powders were prepared by the polymeric precursor method. X-ray diffraction (XRD), FT-Raman spectroscopy, transmission electron microscopy (TEM), and N2 and CO2 adsorption were used for the microstructural and surface characterization of the powders. Room temperature photoluminescence (PL) was observed in Ca1-xLaxTiO3 amorphous particles. The PL intensity of these powders was found to be dependent on the lanthanum molar concentration.
Autonomic dysreflexia in a tetraplegic patient due to a blocked urethral catheter: spinal cord injury patients with lesions above T-6 require prompt treatment of an obstructed urinary catheter to prevent life-threatening complications of autonomic dysreflexia
BackgroundThe Manchester Triage System is commonly used as the triage system in emergency departments of the UK. As per the Manchester Triage System, patients presenting with retention of urine to the accident and emergency department are categorized to yellow, which denotes that the ideal maximum time to first contact with a treating clinician will be 60 min. Cervical spinal cord injury patients, in whom urinary catheter is blocked, may develop suddenly headache, sweating, high blood pressure, cardiac dysrhythmia, convulsions, intracranial bleed, and acute neurogenic pulmonary oedema as a result of autonomic dysreflexia due to a distended bladder.Case presentationA 46-year-old male with C-6 tetraplegia developed urinary retention because of a blocked catheter. He was seen immediately on arrival in the spinal injuries unit. The blocked catheter was removed and a new catheter was about to be inserted. Then this patient said that the ceiling lights were very bright and glaring. Five milligrams of Nifedipine was given sublingually. This patient started having fits involving his head, face, neck and shoulders with loss of consciousness. A 14-French silicone Foley catheter was inserted per urethra without any delay and 300 ml of clear urine was drained. This patient recovered consciousness within 5 min. Computed tomography of the brain revealed no focal cerebral or cerebellar abnormality. There was no intra-cranial haemorrhage.ConclusionThis case illustrates that spinal cord injury patients with lesion above T-6, who develop retention of urine because of a blocked catheter, may look apparently well, but these patients can develop suddenly life-threatening autonomic dysreflexia. Therefore, spinal cord injury patients, who present to the accident and emergency department or spinal units with a blocked urinary catheter, should be seen urgently although their vital signs may be stable on arrival. Increasing the awareness of staff in emergency departments regarding autonomic dysreflexia as well as education of the patient and carers will be useful in preventing this complication in persons with spinal cord injury.