The purpose of this study was to evaluate the reactions of rat subcutaneous connective tissue and bone tissue to iRoot SP, ProRoot MTA, and AH Plus. Specimens were implanted in the dorsal subcutaneous connective tissue and tibias of 36 Wistar rats. Tissue specimens were collected after rats were sacrificed at 7, 30, and 60 days after implantation. Histologic evaluations comprising inflammation severity and new bone formation were blindly made on hematoxylin and eosin-stained sections. In subcutaneous implant test, AH Plus group showed more infiltration of inflammatory cells than the other three groups at 30 days (p<0.05). In intraosseous implant test, number of inflammatory cells decreased in all groups at 7, 30, and 60 days after implantation with no statistically significant differences. Given the similar inflammatory reactions to iRoot SP and MTA, it was concluded that iRoot SP and MTA were biocompatible with the subcutaneous and intraosseous tissues of rats.

Patients’ postoperative facial swelling following third molars extraction may have both biological impacts and social impacts. The purpose of this study was to evaluate the accuracy of artificial neural networks in the prediction of the postoperative facial swelling following the impacted mandibular third molars extraction. The improved conjugate grads BP algorithm combining with adaptive BP algorithm and conjugate gradient BP algorithm together was used. In this neural networks model, the functional projective relationship was established among patient’s personal factors, anatomy factors of third molars and factors of surgical procedure to facial swelling following impacted mandibular third molars extraction. This neural networks model was trained and tested based on the data from 400 patients, in which 300 patients were made as the training samples, and another100 patients were assigned as the test samples. The improved conjugate grads BP algorithm was able to not only avoid the problem of local minimum effectively, but also improve the networks training speed greatly. 5-fold cross-validation was used to get a better sense of the predictive accuracy of the neural network and early stopping was used to improve generalization. The accuracy of this model was 98.00% for the prediction of facial swelling following impacted mandibular third molars extraction. This artificial intelligence model is approved as an accurate method for prediction of the facial swelling following impacted mandibular third molars extraction.

The sudden emergence and rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variant has raised questions about its animal reservoir. Here, we investigated receptor recognition of the omicron’s receptor-binding domain (RBD), focusing on four of its mutations (Q493R, Q498R, N501Y, and Y505H) surrounding two mutational hotspots. These mutations have variable effects on the RBD’s affinity for human angiotensin-converting enzyme 2 (ACE2), but they all enhance the RBD’s affinity for mouse ACE2. We further determined the crystal structure of omicron RBD complexed with mouse ACE2. The structure showed that all four mutations are viral adaptations to mouse ACE2: three of them (Q493R, Q498R, and Y505H) are uniquely adapted to mouse ACE2, whereas the other one (N501Y) is adapted to both human ACE2 and mouse ACE2. These data reveal that the omicron RBD was well adapted to mouse ACE2 before omicron started to infect humans, providing insight into the potential evolutionary origin of the omicron variant.