RESUMEN
We report a rapid cross-linking strategy for the fabrication of polymer hydrogels based on a thiol-disulfide cascade reaction. Specifically, thiolated polymers (e.g., poly(ethylene glycol), hyaluronic acid, sodium alginate, poly(acrylic acid), and poly(methylacrylic acid)) can be cross-linked via the trigger of Ellman's reagent, resulting in the rapid formation of hydrogels over 20-fold faster than that via the oxidation in air. The gelation kinetics of hydrogels can be tuned by varying the polymer concentration and the molar ratio of Ellman's reagent and free thiols. The obtained hydrogels can be further functionalized with functional moieties (e.g., targeting ligands) for the selective adhesion of cells. This approach is applicable to various natural and synthetic polymers for the assembly of hydrogels with a minimized gelation time, which is promising for various biological applications.
RESUMEN
Objectives: To compare the accuracy of three-dimensional transvaginal ultrasound and magnetic resonance imaging in the diagnosis of scar pregnancy. Methods: The records of 54 patients with scar pregnancy, who underwent three-dimensional transvaginal ultrasound and magnetic resonance imaging (MRI), from June 2015 to November 2021 were reviewed. Surgery / histopathology of operative findings were analyzed as gold standard to compare the diagnosis of the two examination methods. Results: The detection rate of scar pregnancy by three-dimensional transvaginal ultrasound was 94.44%, which was not significantly different from MRI (96.30%, P>0.05). The accuracy, specificity and sensitivity of transvaginal three-dimensional ultrasonography in the diagnosis of scar pregnancy were 94.44%, 66.67% and 96.08%, respectively, and were not significantly different from MRI, 96.30%, 50.00% and 98.08% (P>0.05). The detection rates of yolk sac, embryo and heart tube pulsation by three-dimensional transvaginal ultrasound were higher than those detected by MRI (P<0.05). The detection rates of intrathecal hemorrhage, scar infiltration and uterine hematocele by MRI were significantly higher compared to three-dimensional transvaginal ultrasound (P<0.05). There was no significant difference between the two methods (P>0.05). Conclusion: Both three-dimensional transvaginal ultrasound and MRI have good diagnostic efficacy in the diagnosis of scar pregnancy. Detection rates of scar pregnancy diagnostic criteria differ between the two methods, and if necessary, the two methods can be used together, to further improve the diagnostic accuracy of scar pregnancy.
RESUMEN
In this study, superparamagnetic ß-CD-MnFe2O4 with a large surface area was synthesized via a facile co-precipitation method, with ß-cyclodextrin (ß-CD) acting as a coating agent. The as-prepared ß-CD-MnFe2O4 exhibited better catalytic performance than bare MnFe2O4 in terms of activating peroxymonosulfate (PMS) to degrade 2,4-dichlorophenol (2,4-DCP) over a broad pH range of 5-11. Electron spin resonance spectroscopy (ESR) and free radical quenching experiments indicate that various active species (SO4-/OH/O2-/1O2) are generated in the ß-CD-MnFe2O4/PMS system and that pollutants trapped in the cyclodextrin cavity are quickly degraded. Various reaction parameters of the ß-CD-MnFe2O4/PMS system and the stability of ß-CD-MnFe2O4 were also investigated. The results indicate that ß-CD-MnFe2O4 is promising for use in water purification owing to its excellent magnetic separation and recovery properties and good resistance to humic acid (HA).
