Synthesis and Characterization of a New Copolymer Consisting of Polyamide 1210 and Reactive Phosphorus-Nitrogen Flame-Retardant.

The thermal stability and reactivity of organophosphorus flame-retardants play a critical role in synthesizing copolymerized flame-retardant polyamides. Herein, this work successfully synthesizes a flame-retardant CEPPA-DDA salt (CDS) with both good thermal stability and high reactivity by reacting 2-carboxyethyl phenyl phosphonic acid (CEPPA) with 1,12-dodecanediamine (DDA). Flame-retardant polyamide 1210 (FRPA) is further prepared by copolymerizing the CDS, DDA, and sebacic acid (SEA). The test results show that the introduction of CDS can significantly improve the flame-retardant properties of FRPA. Specifically, the flame-retardant polyamide 1210 (FRPA-7) with 7 wt% CDS addition can reach V-0 grade according to UL-94 standard, accompanying limiting oxygen index value of 30.2% and tensile strength of 38.62 MPa. Compared with pure polyamide 1210, the peak heat release rate and total heat release rate of FRPA-7 reduce by 24.11% and 9.40%, respectively. This study provides a simple strategy to prepare flame-retardant polyamides with high flame retardancy and good mechanical properties, which are expected to show great potentials in future industrial applications.

Role of honey in preventing radiation-induced oral mucositis: a meta-analysis of randomized controlled trials.

BACKGROUND: Radiotherapy-induced mucositis easily arouses oral ulceration, pain and xerostomia. Intense pain, difficulty swallowing and speaking greatly affect the quality of life and the treatment process. OBJECTIVE: This study aimed to examine the effects of honey in preventing and treating radiotherapy-induced mucositis in patients with head and neck cancer using a different analytical strategy. METHODS: Articles published until July 2020 were searched across PubMed, Embase, and Cochrane Library databases. Randomized controlled trials that evaluated honey were assessed by two reviewers. The number of mucositis incidences was the primary outcome. Weight loss, pain scale and incidence of severe pain were pooled to be calculated as secondary outcomes. Statistical analyses were conducted using RevMan5.3 software. The funnel plot was used to detect publication bias. RESULTS: Overall, 11/179 records with 715 patients who received radiotherapy were included. Honey significantly reduced the incidence of grade 2 (OR: 0.43, 95%CI: 0.54-0.98, P = 0.03), grade 3 (odds ratio [OR]: 0.24, 95% confidence interval [CI]: 0.16-0.35, P < 0.001) and grade 4 mucositis (OR: 0.17, 95%CI: 0.08-0.36, P < 0.001). In grade 1 (OR: 1.54, 95%CI: 1.15-2.06, P = 0.003), and honey was not significant in preventing radiation-induced mucositis. The incidence of unbearable pain was lower in the honey group at all grades (OR: -0.20, 95%CI: -0.33 to -0.07). The effect of honey on weight loss and pain score was not statistically significant. CONCLUSION: Honey can prevent and alleviate grade 2-4 mucositis, especially in high grade mucositis. Honey also provides some relief from severe pain. But, more evidence is required to prove that honey is an effective substance for relieving pain or minimizing weight loss.

Histological characteristics following a long-term nitrate-rich diet in miniature pigs with parotid atrophy.

The aim of this study was to investigate the histological characteristics following a 2-year nitrate-rich diet in miniature pigs with parotid atrophy. Using averages collected data from three time points at 6, 12, and 24 months following the induction of parotid gland atrophy, salivary nitrate levels of the nitrate-diet parotid-atrophied group (17.3 ± 3.9 ng/µl) were close to those of the control group (19.6 ± 5.1 ng/µl). Compared to the control group, the nitrate-diet group had significantly higher nitrate levels in blood (P < 0.05) and urine (P < 0.001). Histological and electron microscopy analyses showed no abnormalities in the organs of experimental or control animals. No significant differences on apoptosis rate were found in liver and kidney tissues between the standard- and nitrate-diet groups. Therefore, dietary nitrate supplementation could restore salivary nitrate levels. High-dose nitrate loading for 2 years had no observed systemic toxicity in miniature pigs with parotid atrophy.