AIM:To study the parameters of supercritical CO_2 extraction of essential oil from valeriana efficinalis by orthogonal design. METHODS: Four factors,such as extraction pressure,extraction temperature,extraction time and separation temperature were chosen by the observation of orthogonal design,each factor was assigned to three levels.Bornyl acetate content was selected as a marker in a position to determine optimal extraction. RESULTS: Pressure and temperature were the main factors in effecting the extraction of bornyl acetate,extraction time was minor factor relatively. CONCLUSION: The optimal extraction is as follow,parameters were extraction pressure:12 MPa,extraction temperature:45 ℃,extraction time:1 hour,separation temperature:35 ℃,it gave the best recoveries of essential oils and bornylacetate.

ObjectiveTo investigate the role of reducing the door-to-needle time for patients with acute ischemic stroke based on the quality improvement program of PDCA cycle.MethodsConsecutive patients with acute ischemic stroke admitted to hospital were registered prospectively from January 1, 2016 to September 30, 2016.Questionnaires and time tracking method were used to investigate the door-to-needle (DNT) and its influencing factors.PDCA cycle method was used to improve the stroke channel workflow and the changing trend of DNT was analyzed.ResultsA total of 71 patients with acute ischemic stroke were enrolled.After 3 PDCA cycles, DNT (median, interquartile range) from 100.0 min (65.5-127.0 min) reduced to58.0 min (45.5-80.0 min) (Z=11.689, P<0.001), the proportion of the patients with DNT ≤60 min increased from 19.05% to 60.00% (χ2=7.893, P=0.019).Conclusions The quality improvement program of PDCA cycle may effectively reduce the time of DNT in patients with acute ischemic stroke.