Methodological study on the establishment of limit values in the Standards of Drinking Water Quality / 中华预防医学杂志

The establishment of limit values for standards of drinking water quality is an important and complex process. This study systematically introduced the methodology of the establishment of standard limit values for drinking water quality and elaborated on the workflow of setting limit values of water quality indicators, principles and methods of selecting water quality indicators, derivation of safety reference values, and establishment of limit values. It also aimed to provide reference and support for the future revision of relevant standards.

Research on the standard limits for vinyl chloride and trichloroethylene in the "Standards for Drinking Water Quality（GB5749-2022）" in China / 中华预防医学杂志

The usage of vinyl chloride and trichloroethylene in China has been increasing year by year, and they have been detected in both drinking water and environmental water, making them important environmental pollutants. Based on the latest research results on the health effects of vinyl chloride and trichloroethylene, the newly issued, "Standards for Drinking Water Quality (GB5749-2022)" in China has adjusted the standard limit of vinyl chloride from 0.005 mg/L to 0.001 mg/L and the standard limit of trichloroethylene from 0.07 mg/L to 0.02 mg/L. This article analyzed and discussed the relevant technical contents for determining the above standard limits, including the levels and exposure conditions of vinyl chloride and trichloroethylene in the water environment, health effects, derivation of safety reference values, and determination of hygiene standard limits. Suggestions were also made for the implementation of this standard.

Research on the establishment of standard limits for perfluorooctanoic acid and perfluorooctane sulfonate in the "Standards for Drinking Water Quality（GB5749-2022）"in China / 中华预防医学杂志

Perfluorinated compounds, especially Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are widely detected in water environments in China. Considering the potential health risks of drinking water exposure routes, PFOA and PFOS have been added to the water quality reference index of the newly issued "Standards for Drinking Water Quality (GB5749-2022)", with limit values of 40 and 80 ng/L, respectively. This study analyzed and discussed the relevant technical contents for determining the limits of the hygiene standard, including the environmental existence level and exposure status of PFOA and PFOS, health effects, derivation of safety reference values, and determination of hygiene standard limits. It also proposed prospects for the future direction of formulating drinking water standards.

Application of tunable guide device in prominent mandibular angle osteotomy / 中华整形外科杂志

<p><b>OBJECTIVE</b>To discuss the application and therapeutic effect of tunable guide device in correction of prominent mandibular angle.</p><p><b>METHODS</b>Since 2007, 50 cases with prominent mandible angle underwent mandible angle osteotomy with the tunable guide device. The patients were followed up for 3-6 months.</p><p><b>RESULTS</b>No severe complication happened. Local seroma occurred in one case. Improved esthetic results were achieved at both frontal and oblique view.</p><p><b>CONCLUSIONS</b>The mandibular angle osteotomy with the tunable guide device makes the procedure safe and easily performed.</p>

Changes of different section area at different parts of upper-airway after Le Fort III osteotomy / 中华整形外科杂志

<p><b>OBJECTIVE</b>To observe the therapeutic effects of Le Fort III osteotomy and midface distraction osteogenesis (DO) on the upper-airway narrow.</p><p><b>METHODS</b>Since 2000, 11 cases (10 cases of Crouzon syndrome and 1 case of Apert syndrome) with severe midface deficiency were treated with Le Fort III osteotomy and midface DO. The section area of different parts of upper-airway were tested by computer assistants image measurement preoperatively and postoperatively. Some patients received sleep function monitoring.</p><p><b>RESULTS</b>The face appearance and the function of upper-airway improved significantly after Le Fort III osteotomy and Midface DO. The section area at the level of posterior nasal spine and uvula increased obviously after treatment (P < 0.05), however the section area at the level of epiglottis and separation between airway and esophagus were not obviously enlarged (P > 0.05).</p><p><b>CONCLUSIONS</b>Midface DO after Le Fort III osteotomy can effectively improve the upper-airway narrow, especially the upper part from uvula.</p>

3-dimensional position changes of periorbital structures after midface distraction osteogenesis / 中华整形外科杂志

<p><b>OBJECTIVE</b>To evaluate the 3-D position changes of periorbital structures after midface distraction osteogenesis in patients with Crouzon syndrome.</p><p><b>METHODS</b>The CT data of 8 cases who had accepted the midface distraction osteogenesis following Le Fort III osteotomy were retrospectively analyzed. The patients were averagely 11.9 years old, and the CT was performed before and one year after operation. After 3-D image reconstruction, a right-hand coordinate system based on the preoperational Frankfurt Plane was then established. The pre- and post-operative positions of the superior orbit point (SOr), inferior orbit point (IOr), median orbit point (MOr), lateral orbit point (LOr), anterior ocularis point (AO), ocularis eyeball point (PO) and the four insertion ocularis rectus were documented and compared. The positions of these marked points in normal controls were also documented and compared with those in patients.</p><p><b>RESULTS</b>After midface distraction osteogenesis, the position of AO was not changed significantly on the y-axis and z-axis, but the distance between two AO points on x-axis was reduced by 3.40 mm; IOr moved averagely 12.24 mm on y-axis and 4.25 mm on z-axis, MOr moved averagely 10.11 mm on y-axis and 2.80 mm on z-axis, LOr moved averagely 9.86 mm on y-axis and 2.31 mm on z-axis. The Inferior Rectus attachment moved averagely 3.63 mm on y-axis and 2.98 mm on z-axis. No other significant change was observed on other marked points.</p><p><b>CONCLUSIONS</b>Midface distraction osteogenesis following Le Fort III osteotomy can significantly move the medial, lateral and inferior peri-orbital bone structure anteriorly and inferiorly. The eyeballs have no markedly sagittal position changes after distraction except slight medial, downwards movements and anterior-upwards rotations.</p>

Experience of midfacial distraction osteogenesis in upper airway stenosis / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the therapeutic effects of upper airway stenosis after Le Fort III osteotomy and midfacial distraction osteogenesis (DO).</p><p><b>METHODS</b>Eleven cases (age, 5-16 yrs) with severe midface dysostosis complicated with exophthalmos, anterior crossbite and upper airway stenosis were treated by using Le Fort III osteotomy and midfacial DO from August 2000 to February 2007. The 3D reconstruction of the upper-airway from CT data was used to evaluate the upper airway volume before and after the operation. And meanwhile polysomnography was carried out to demonstrate the upper airway functional changes.</p><p><b>RESULTS</b>There was a 64.3% mean increase [mean, (9.13 +/- 6.94) ml, P < 0.05] in upper airway volume in the 11 cases after the operations. It showed that there was significant improvements in the indexes of polysomnography after the operations, such as apnea and hypopnea index, average SaO2, minimum oxygen saturation and snore index.</p><p><b>CONCLUSIONS</b>The Le Fort III osteotomy and midfacial distraction osteogenesis can efficiently relieve the symptoms of upper-airway stenosis in severe midfacial dysostosis.</p>