[Efficacy and safety of low-dose levonorgestrel-releasing intrauterine system in Chinese women: a multicenter, single-arm, open labeled interventional trial]

Objective: To evaluate the efficacy, bleeding profile and safety of low-dose levonorgestrel-releasing intrauterine system (LNG-IUS 8) in Chinese healthy women of childbearing age. Methods: A multi-center, open-label, single-arm clinical trial conducted at 16 centres in China enrolled 773 healthy women of childbearing age (mean age 31.6 years old, range 18 to 40 years old) , who demanded contraception, from April 2006 to June 2013. All women placed LNG-IUS 8 for 3 years and then been followed up at 3, 6, 9, 12, 18, 24, 30, 36 months. The efficacy variables including pregnancy rate and expulsion rate were analyzed using life table, while observing adverse events (AE) to evaluate the safety. The bleeding profile happened during the study was assessed using 90-day reference intervals (World Health Organization criteria) . Results: Eight pregnancies occurred among 773 women, resulting in a overall Pearl index of 0.42 per 100 women years. The 3-year cumulative pregnancy rate was 0.37 per 100 women years and the 3-year cumulative expulsion rate was 1.99 per 100 women years. The number of women with bleeding/spotting reduced and the bleeding/spotting days declined over time. Totally 219 AE were reported related to LNG-IUS 8 placements. The most common AE were vaginal bleeding (8.2%, 63/773) and the ovarian cyst (6.2%, 52/773) . LNG-IUS 8 had an improving effect on dysmenorrhea that the percentage of women with dysmenorrhea as well as the days of dysmenorrhea decreased over time. The percentage of women satisfied or very satisfied with LNG-IUS 8 was 87.2% (622/713) . Conclusion: LNG-IUS 8 is highly effective and safe for Chinese healthy women of childbearing age.

Microbridge Testing of Thin Films Under Small Deformation

The present work proposes a novel microbridge testing method to simultaneously evaluate the Young's modulus, residual stress of thin films under small deformation. Theoretic analysis and finite element calculation are conducted on microbridge deformation to provide a closed formula of deflection versus load, considering both substrate deformation and residual stress in the film. Silicon nitride films fabricated by low pressure chemical vapor deposition on silicon substrates are tested to demonstrate the proposed method. The results show that the Young's modulus and residual stress for the annealed silicon nitride film are respectively 202 GPa and 334.9 MPa.

[Determination of carfentrazone-ethyl(F8426) residue in soil and wheat by wide-bore capillary gas chromatography]

An efficient method for determining F8426 of Affinity 40 DF in soil and wheat is described. F8426 was extracted from the soil and the wheat sample with acetone-water (80:20, volume ratio), and the extract was partitioned with petroleum ether. Then the upper layer was concentrated and cleaned up on a micro-column of Florisil and activated carbon mixture. Finally F8426 was separated from other interfering components through wide-bore capillary gas chromatographic column (OV-1701, 12 m x 0.53 mm i.d.), and was detected by electron capture detector (ECD). The lowest detection limit for F8426 was 0.02 ng. The lowest detectable concentrations in wheat and soil was 2 micrograms/kg and 1 microgram/kg respectively. The average recovery and coefficient of variation of this method were 89.60%-97.53% and 4.42%-8.67% respectively. This method is simple, sensitive and suitable for residue analysis of F8426.