Comparison of Postoperative Outcomes Between Envelope and Triangular Flaps After Mandibular Third Molar Surgery: A Systematic Review and Meta-Analysis.

PURPOSE: The objective of the present systematic review was to compare the postoperative outcomes between envelope and triangular flaps after mandibular third molar surgery. MATERIALS AND METHODS: The PubMed, Embase, Web of Science, and Cochrane Library databases were systematically searched from the inception date to November 2018. Randomized and nonrandomized controlled trials were included if they had met certain inclusion and exclusion criteria. The predictor variable was the flap design, envelope or triangular. The outcome variables were operation time, pain, trismus, alveolar osteitis (AO) incidence, wound dehiscence, and swelling. The methodologic quality assessment was performed in accordance with the Cochrane Collaboration guidelines. The meta-analysis was performed using Review Manager, version 5.2. RESULTS: A total of 21 studies were included for qualitative synthesis, 18 of which were included in the meta-analysis. The use of envelope flaps required less operation time than triangular flaps (P < .00001; I2 = 9%). In the Pell and Gregory A and B subgroups, envelope flaps were associated with a significantly lower visual analog scale score at 3 (P = .05, I2 = 0%) and 7 (P = .02; I2 = 0%) postoperative days and with a greater postoperative interincisal distance at 7 postoperative days (P = .04; I2 = 0%). In contrast, envelope flaps were associated with a greater AO incidence in the subgroup of split-mouth randomized controlled trials (P = .001; I2 = 0%). CONCLUSIONS: Envelope flaps required a shorter operation time than triangular flaps and were associated with less postoperative pain and trismus when applied to impacted mandibular third molars of Pell and Gregory Class A or B. In contrast, triangular flaps were associated with a decreased incidence of AO compared with envelope flaps.

Incidence and risk factors of severe acute high-altitude illness in healthy adults first entering the northern Tibetan Plateau of over 5,000 m.

Background: Our study was designed to determine the incidence and risk factors of severe acute high-altitude illness (AHAI) in healthy adults first entering the northern Tibetan Plateau of over 5,000 m. Methods: In our prospective observational study, we enrolled 500 people who were scheduled for fast ascension to the northern Tibetan Plateau. The primary outcome variable was severe AHAI, defined as the presence of serious symptoms that could not be ameliorated by general treatment and required evacuation to lower altitudes. According to the inclusion and exclusion criteria, a cohort of 383 healthy people was included in the statistical analysis. We calculated the incidence of severe AHAI, identified the risk factors, and the differences in the most severe symptoms experienced. Results: Sixty-eight people were diagnosed with severe AHAI, and the incidence was 17.8%. Compared to individuals without severe AHAI, those with severe AHAI were more likely to be over the age of 40 years, of Han Chinese nationality, and living at an altitude of <1,500 m. They were less likely to belong to the Yi nationality, had a lower altitude of permanent residence, and exhibited decreased levels of lymphocyte count and hemoglobin concentration. Multivariable logistic regression showed that the mean altitude of permanent residence [per kilometer, adjusted odds ratio (AOR) = 0.464; 95% confidence interval (CI), 0.304-0.708; p < 0.001] and lymphocyte count (AOR = 0.606; 95% CI, 0.378-0.970; p = 0.037) were the independent risk factors. Headache and dyspnea ranked in the top two of the most severe symptoms for people with severe AHAI. Conclusion: Living at lower altitudes and having a decreased lymphocyte level were the risk factors of severe AHAI in healthy adults first entering the plateau of over 5,000 m.

Assessment of Psychological and Social Fitness in Healthy Adults Permanently Living at Very High Altitude.

BACKGROUND: Environmental factors of high altitude, especially hypobaric hypoxia, may directly and persistently affect human physical and mental health. Our study was designed to assess the psychological and social fitness in healthy adults permanently living at very high altitude, i.e., an average elevation of 3650 m. METHODS: In our observational study, 320 participants were included, among which 218 (68.1%) had resided in such a setting for more than 20 years. Participants underwent 138 assessments, including the Self-Rating Anxiety Scale (SAS), Symptom Check List 90 (SCL-90) and the Evaluation Scale of Human Adaptation Capability (ESHAC). SAS (20 items) and SCL-90 (90 items) were used to assess psychological fitness, and the ESHAC (28 items) was used to assess social fitness. Pearson analysis was used to assess correlations and Logistic regression analysis was performed to determine independent influencing factors. RESULTS: The highest SAS score was 80 and the mean score was 43.26 ± 8.88, which was higher than the norm in China (p < 0.001). Sixty (18.8%) participants showed anxiety symptoms and 14 (4.4%) had moderate or severe anxiety. The average score of SCL-90 was 140.88 ± 44.77, and 96 (30.0%) participants showed SCL-90 scores ≥160. Compared with the norm, significant differences were shown in eight of the nine SCL-90 factor scores, i.e., somatization, obsessive-compulsive, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism. The average score of ESHAC was 19.92 ± 4.54, and 114 (35.6%) participants did not reach the qualifying standard. Significant correlations were observed between the SAS score, SCL-90 total and factor scores, and ESHAC scores. The Logistic regression analysis showed that being born at very high altitude was an independent influencing factor (AOR = 2.619; 95% CI, 1.629-4.211; p < 0.001) after controlling for other factors. CONCLUSION: Permanently living at very high altitude can influence the psychological and social fitness of healthy adults.

A heat-flux upper boundary for modeling temperature of soils under an embankment in permafrost region.

Building roads in permafrost region is challenged because permafrost is sensitive to temperature increase. As an embankment gains/drains heat mostly at the upper surface, accurately modeling the heat transfer in the upper surface is crucial to understand the thermal stability of the road. Popular methods treat the upper boundary as a temperature-controlled model (TCM), where temperature of the upper surface is set as a sinusoidal function. This simple function, however, fails to identify the influences of solar irradiance, heat convection, and thermal irradiance on the heat transfer on the ground surface. Here we introduce a heat-flux model (HFM) to calculate the heat fluxes at the embankment upper surface and at the adjacent ground surface. HFM-predicted temperature under an embankment is compared against the observed temperature to validate the model, and is compared to the TCM-predicted temperature. While TCM-predicted temperatures and HFM-predicted ones are similar in trend and in pattern, the HFM-predicted temperatures are far more coincident with the observed ones. The pros and cons of both HFM and TCM are discussed. Further studies are expected to use HFM to understand the heat flux components such as solar absorption, heat convection, and thermal irradiance on the temperature of permafrost under embankments.

[Optimization of preparation for matrine-loaded magnetic chitosan microspheres].

OBJECTIVE: To study the technique of preparation and optimization of magnetic chitosan microspheres. METHODS: Magnetic fluid was produced by co-precipitation method and magnetic chitosan microspheres were produced using a convenient method of ionic gelation. A global optimization algorithm was used to optimize the parameters. RESULTS: The formulated magenetic fluid and microspheres were characterized size and the size distribution. The average particle size of magnetic fluid and matrine-loaded chitosan magnetic microspheres were found to be 152.2 nm and 682.4 nm. CONCLUSION: Global optimization algorithm is an efficient method to optimize the parameters.

[Study on the preparation of matrine-containing nanocell].

OBJECTIVE: To Study the preparation and optimization of matrine-containing nanocell. METHODS: Using the film-ultrasonic method and global optimization algorithm to prepare and formulate matrine-containing nanocell. UV spectrophotometry was used to determine the entrapment efficiency of the astragalan. Laser beacon was used to determine the diameter distribution of the nanocells. Using the scanning probe microscope to observe the surface topography of the nanocell. Transmission electron microscope was used to inspect the core-shell structure of the nanocell. RESULTS: The matrine-containing nanocells appeared to be round, integrated, well separated and uniform in size with high entrapment efficiency, the average particle size of the matrine-containing nanocells was 300 nm and the astragalan entrapment efficiency was above 90%. Preparation technology had fine reproducibility. CONCLUSION: Using global optimization algorithm can prepare and optimize matrine-containing nanocell.