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The evolution of structure and properties of natural rubber (NR) for vibration damping products during storage was studied by long-term storage method and accelerated aging method. The results showed that the hardness, modulus at 100%, modulus at 300%, storage modulus and loss modulus of NR vulcanizates increased gradually with increase of aging temperature and aging time, and the overall change trend was similar to that of crosslinking density. The change rates of tensile strength and elongation at break decreased while the loss factor decreased rapidly and tended to be stable. The ratio of dynamic stiffness and static stiffness decreased first and then increased slowly. Hot air aging had little effect on the vibration reduction performance of NR vulcanizates.

Reclaimed rubbers with different Mooney viscosity were used to replace all the aromatic oil and part of carbon black in the formula of passenger car tyre tread compounds. The effects of Mooney viscosity and carbon black replacement ratio of reclaimed rubber on curing characteristics, physical and mechanical properties, aging resistance and dynamic mechanical properties of tread vulcanizates were investigated. The results showed that when the replacement mass ratio of reclaimed rubber to carbon black was 5/1, the tread vulcanizates had better physical and mechanical properties and aging resistance. Compared with high Mooney viscosity reclaimed rubber, the tread vulcanizate with low Mooney viscosity reclaimed rubber had higher curing efficiency and better tensile properties. Both high and low Mooney viscosity reclaimed rubber could reduce the rolling resistance of tread vulcanizates, while the wear resistance was maintained.

Objective: To explore the effect of early swallowing training on postoperative outcomes of patients who had undergone oral cancer surgery plus free flap reconstruction. Subjects and Methods: In this prospective, randomized controlled trial, 121 patients who had undergone oral cancer surgery plus free flap reconstruction were randomly assigned to the control (n = 59) or intervention group (n = 62). The control group underwent routine nursing measures. The intervention group received swallowing training on the sixth postoperative day. On the 15th day and 1 month after surgery, the swallowing function (Mann Assessment of Swallowing Ability‐Oral Cancer [MASA‐OC] score), weight loss rate, time of nasogastric tube removal, and quality of life were evaluated. Results: Patients in the intervention group had higher MASA‐OC scores and better weight loss rates than those in the control group on the 15th day (MASA‐OC: p = 0.014, weight loss: p < 0.001) and 1 month (both p < 0.001) after surgery. The time of nasogastric tube removal and the quality of life was statistically significant between groups (p < 0.001). Conclusion: Early swallowing training improves the swallowing function, nutritional status, and quality of life and shortens the indwelling time of nasogastric tube of patients who have undergone oral cancer surgery plus free flap reconstruction. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate clinical features of atypical pulmonary tuberculosis (aPTB) mimicking bacterial pneumonia, determine imaging features with the highest degree of correlation, and identify predictors for acid-fast bacilli (AFB) positivity.

Objective: Determine the safety and effectiveness of a nasogastric tube removal plan designed to shorten nasogastric tube indwelling time after oral cancer surgery plus free flap reconstruction. Materials and Methods: A parallel randomized clinical trial was conducted from May 2021 to December 2021 at Peking University School of Stomatology. Volunteers (n = 128) were separated into four groups: non‐tracheostomy control and intervention groups and tracheostomy control and intervention groups. Control patients received the conventional nasogastric tube removal plan. Non‐tracheotomy intervention patients were asked to swallow 5 ml of water on the first postoperative day. If there was no coughing, they were allowed progressively increasing amounts of water for the following 2 days. The nasogastric tube was removed only after ensuring level I/II performance on the Watian water swallowing test, no "wet voice" after drinking water, no marked decrease in blood oxygen saturation after drinking, and satisfactory daily oral nutritional intake. Tracheotomy intervention patients received the same protocol plus an additional Watian water swallowing test after tracheal tube removal. Results: Nasogastric tube removal time was earlier in the intervention subgroups than in control subgroups: 5.0 ± 2.3 days versus 7.8 ± 3.9 days (p = 0.001) in non‐tracheostomy patients and 9.8 ± 1.1 days versus 16.2 ± 13.0 days (p = 0.049) in tracheostomy patients. Incidence of wound complications and daily food intake were comparable between the groups. The incidence of pneumonia was lower in the tracheostomy intervention group than in the tracheostomy control group (12.5% vs. 3.1%, p = 0.162). Pharyngeal pain score was lower in tracheotomy intervention patients than in tracheotomy control patients (p = 0.029). Postoperative hospital stay was shorter in tracheotomy intervention patients than in tracheotomy control patients (p = 0.005). Conclusions: On the basis of ensuring safety and effectiveness, patients undergone free flap reconstruction for oral cancer could be offered oral intake early after surgery, which will not increase the incidence of wound complications and pneumonia or adversely affecting the oral intake of the patients; it can also help minimize pharyngeal pain and shorten postoperative hospital stay of patients with a tracheotomy. Level of Evidence: 2 Laryngoscope, 133:1382–1387, 2023 [ABSTRACT FROM AUTHOR]