RESUMO
Gas sensors based on organic molecules are attractive for their tailored molecular structures and controllable functions, but weak interfacial adhesion between sensing materials and supporting substrates has severely hampered their practical applications, particularly in harsh environments. Here, inspired by the combined anchoring-recognizing feature of natural olfactory systems, an adhesive-integrated-agent strategy to integrate the adhesive unit (poly(dimethylsiloxane)) with the sensing unit (organoplatinum(II)) into one chemistry entity, creating robust and sensitive nanobelt array gas sensors is demonstrated. Systematic theoretical and experimental studies reveal that incorporating adhesive units significantly enhances the interfacial adhesion of the array sensors and gas-bridged super-exchange electronic couplings of sensing units ensure their efficient gas-sensing performance. The high shear strength of ≈7.05 × 106 N m-2 allows these arrays to resist aggressive ultrasonication, tape peeling, or repeated bending without compromising their sensing performance. This molecular engineering strategy opens a new guideline to develop robust gas sensors.
RESUMO
OBJECTIVE: This study aims to explore the rule of changes in serum GGT activity, as well as GGT/ALT and AST/ALT ratios, in primary hepatic carcinoma (PHC) patients with different alpha-fetal protein (AFP) levels. METHODS: GGT, AST and ALT were detected in 370 PHC patients with positive HBs-Ag using a automatic biochemical analyzer, and AFP was detected using a Roche E170 modular analytics immunoassay analyzer. GGT level, as well as AST/ALT and GGT/ALT, ratios were compared among PHC patients with different AFP levels. RESULTS: As shown in Table 1, GGT levels were 109.59 ± 111.06, 151.13 ± 190.43, 135.86 ± 107.62, 151.36 ± 176.59 and 172.58 ± 188.84, respectively, in the groups of primary PHC patients with AFP levels of ⩽ 10, 10-100, 100-200, 200-400 and ⩾ 400 ng/ml; and the differences among these groups were not statistically significant (P> 0.05). AST/ALT ratios were 1.55 ± 1.02, 1.30 ± 0.81, 2.02 ± 1.89, 2.12 ± 1.11 and 1.73 ± 1.25, respectively; and the differences among these groups were not statistically significant (P> 0.05). GGT/ALT ratios were 3.43 ± 3.12, 3.57 ± 5.70, 3.57 ± 2.94, 3.89 ± 4.58 and 3.43 ± 3.61, respectively; and the differences among these groups were not statistically significant (P> 0.05). CONCLUSION: For patients with chronic hepatitis B and cirrhosis after hepatitis B, no matter how AFP level is, when liver function report reveals increased GGT, AST/ALT > 1 and GGT/ALT > 1 (that is, AST > ALT and GGT > ALT), even if AFP is negative, we should also be alert to the existence of PHC.