Progress in Application of Heparin Coating in Blood Contact Medical Devices / 中国医疗器械杂志

Blood compatibility is the main restriction of blood-contacting medical devices in clinical application, especially long-term blood-contacting medical devices will stimulate the immune defense mechanism of the host, resulting in thrombosis. Heparin anticoagulant coating links heparin molecules to the surface of medical device product materials, improves the compatibility between the material surface interface and the body, and reduces the host immune defense reactions. This study reviews the structure and biological properties of heparin, the market application status of heparin-coated medical products, the insufficiency and improvement of heparin coating, which can provide a reference for the application research of blood contact medical devices.

Epidemiology of allergic rhinitis in children in grassland of Inner mongolia / 中华耳鼻咽喉头颈外科杂志

Objective@#To investigate the self-reported prevalence, clinical characteristics, complications of allergic rhinitis (AR) and the sensitization of outdoor air pollen allergens in children in the Inner mongolia grassland region.@*Methods@#A multistage, stratified and random clustered sampling with a face-to-face interview survey study in children from 0 to 17 years old was performed together with 10 common allergen skin prick tests (SPT) and measurements of the daily pollen count in 6 regions in the Inner mongolia grassland region from May to August of 2015. SAS 9.4 software was used for data analysis.@*Results@#A total of 2 443 subjects completed the study. The self-reported prevalence of AR was 26.6%. The prevalence of boys was higher than that of girls (28.8% vs 24.3%, χ2=6.157, P<0.05). Subjects from urban areas showed higher prevalence than rural areas (34.7% vs 18.8%, χ2=79.107, P<0.05). There was significant regional difference in the prevalence of AR among the six areas investigated (χ2=221.416, P<0.05). The main clinical symptoms of AR were sneezing (88.2%) and nasal congestion (78.6%). Among combined diseases, asthma accounted for 16.5% (107/650), rhinoconjunctivitis accounted for 47.9% (311/650). The peak season of AR was April and July, with the top SPT positive allergens of Artemisia species and chenopodium in this area.@*Conclusions@#The prevalence AR in children in the Inner mongolia grassland region is extremely high. Sneezing is the main clinical symptom. Rhinoconjunctivitis is the most common combined disease. High summer and autumn pollen exposure is the main cause of AR.

Finite element analysis of periodontal tissue stress distribution of labial inverted impacted maxillary central incisor / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aims to do the following: construct a three-dimensional finite element model of an labial inverted impacted maxillary central incisor and its supporting tissues, analyze stress distribution in the periodontal tissue when various tractions are exerted, and provide references for treating impacted maxillary central incisor.</p><p><b>METHODS</b>A three-dimensional finite element model oflabial inverted impacted maxillary central incisor and its periodontal tissues was established using Mimics 10.01 and Ansys 14.0 software based on original cone beam computed tomography (CBCT) data. Various traction values (20, 30, 40, 50, 60, and 70 g) were exerted on the incisal margin in the direction perpendicular to the impacted tooth. Different Von Mises stress values were determined.</p><p><b>RESULTS</b>Stress distribution on the periodontal ligament increased with traction size. When 30 g traction was exerted on the labial inverted impacted maxillary central incisor, the Von Mises stress was 24 919.0 Pa, which was within the range of the optimum force and close to its maximum value.</p><p><b>CONCLUSION</b>The optimum traction for early orthodontic treatment of labial inverted impacted maxillary central incisor is nearly 30 g.</p>