ABSTRACT
We report an aerosol-based approach to study the thermal stability of metal-organic frameworks (MOFs) for gas-phase synthesis of MOF-based hybrid nanostructures used for highly active catalysis. Temperature-programmed electrospray-differential mobility analysis (TP-ES-DMA) provides the characterization of temperature-dependent morphological change directly in the gas phase, and the results are shown to be highly correlated with the structural thermal stability of MOFs determined by the traditional measurements of porosity and crystallinity. The results show that MOFs underwent thermal decomposition via simultaneous disassembly and deaggregation. Trimeric Cr-based MIL-88B-NH2 exhibited a higher temperature of decomposition ( Td), 350 °C, than trimeric Fe-based MIL-88B-NH2, 250 °C. For UiO-66, a significant decrease of Td by ≈100 °C was observed by using amine-functionalized ligands in the MOF structure. Copper oxide nanocrystals were successfully encapsulated in the UiO-66 crystal (Cu xO@UiO-66) by using a gas-phase evaporation-induced self-assembly approach followed by a suitable thermal treatment below Td (i.e., determined by TP-ES-DMA). Cu xO@UiO-66 demonstrated a very high catalytic activity and stability to CO oxidation, showing at least a 3-time increase in CO conversion compared to the bare CuO nanoparticle samples. The study demonstrates a prototype methodology (1) to determine structural thermal stability of MOFs using a gas-phase electrophoretic method (TP-ES-DMA) and (2) to gas-phase synthesize CuO nanocrystals encapsulated in MOFs.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relevant factors of liver histological changes in chronic hepatitis B (CHB) patients with mildly elevated ALT and to explore the clinical values of these factors on anti-viral treatment.</p><p><b>METHODS</b>A total of 152 CHB patients with mildly elevated ALT (less than 2 x ULN) who underwent liver biopsy were included in the study. Correlations between routine laboratory markers, liver histological inflammation grade and fibrosis stage were statistically assessed by Spearman correlation analysis, one-way ANOVA, area under the curve (AUC) of the receiver operating characteristic curves (ROC) and Logistic regression statistical analysis.</p><p><b>RESULTS</b>All patients in the study showed various hepatic histological damages. Among the 152 patients 50 (32.9%) were found with inflammation grade 1 (G1), 42 (27.6%) with G2, 46 (30.3%) with G3 and 14 (9.2%) with G4. 16 patients (10.5%) were found with fibrosis stage 2 (S2), 25 (16.5%) with S3 and 41 (27.0%) with S4. Routine laboratory markers Alb, BPC and WBC were significantly correlated with hepatic histological inflammation grade and fibrosis stage. Marked liver fibrosis and moderate to severe liver damage were significantly higher in patients aged more than 40 years as compared to those less than 40 years of age (P = 0.002, P = 0.010). The regression equation P = 1/[1+e-(9.36250-1625Alb-0.0234BPC)] was established with sensitivity and specificity of 83.3% and 65.0%, respectively.</p><p><b>CONCLUSION</b>67.8% of CHB patients with mildly elevated ALT have significant injury to the liver tissue. CHB patients aged more than 40 years have a significant increase of marked liver fibrosis and moderate to severe liver damage. The regression equation is valuable to predict whether CHB patients need antiviral therapy or not.</p>
