RESUMO
We report here the analysis of vibrational properties of the sanbornite (low-BaSi2O5) and Ba5Si8O21 using theoretical and experimental approaches, as well as results of high temperature experiments up to 1100-1150 °C. The crystal parameters derived from Rietveld refinement and calculations show excellent agreement, within 4%, while the absolute mean difference between the theoretical and experimental results for the IR and Raman vibrational frequencies was <6 cm-1. The temperature-dependent Raman study renders that both sanbornite and Ba5Si8O21 display specific Ba and Si sites and their BaO and SiO bonds. In the case of the stretching modes assigned to specific Si sites, the frequency dependence on the SiO bond length exhibited very strong correlations. Both phases showed that for a change of 0.01 Å, the vibrational mode shifted 10 ± 2 cm-1. These results are promising for using Raman spectroscopy to track in situ reactions under a wide variety of conditions, especially during crystallization.
RESUMO
OBJECTIVES: The diagnostic performance of cytology in esophageal squamous cell carcinoma (ESCC) is meticulously described. METHODS: Cytological and biopsy specimens were prospectively taken during esophagogastroduodenoscopy of 123 individuals in 2013 and 2014. Cytology samples were maintained in preservative fluid until processing and biopsies were formalin-fixed and paraffin-embedded. RESULTS: Based on endoscopic biopsy results, 70 cases were positive for ESCC whilst 53 were negative for cancer. In addition, brush cytology showed high sensitivity and specificity (98.57 and 96.23%, respectively) in detecting the disease, and high accuracy (97.5%) comparable to that provided by histopathology which is the accepted gold standard. CONCLUSION: Brush cytology specimens preserved in liquid medium may be a good alternative for ESCC diagnosis.
