A simple assay for detection of phospholipase C (PLC) activity was developed based on a fluorescence liposome probe using the Liss Rhod PE-loaded phospholipid liposomes.The liposome probe was prepared by the coassembly of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and fluorescent lipid (Liss Rhod PE).The probe showed very low background fluorescence due to fluorescence self-quenching effect of Liss Rhod PE.As the PLC enzyme selectively digested lipid, the Rhod fluorescence was recovered from its quenched state, leading to the sensitive detection of PLC.This assay provided a limit of detection (at a signal-to-noise ratio of 3) of 2 U/L for PLC.In the presence of PLC inhibitor, the fluorescent response of the sensor for PLC decreased, indicating that the assay could also be used for screening PLC inhibitors.

Objective To evaluate the risk factors and sonographic findings of pregnancies complicated by placenta increta or placenta percreta. Methods Totally, 2219 cases were retrospectively analyzed from 20 tertiary hospitals in China from January 2011 to December 2015. The data were collected based on the original case records. All cases were divided into two groups, the placenta increta (PI) group (79.1％, 1755/2219) and the placenta percreta (PP) group (20.9％, 464/2219), according to the degree of placental implantation. The risk factors and sonographic findings of placenta increta or percreta were analyzed by uni-factor and logistic regression statistic methods. Results The risk factors associated with the degree of placental implantation were age, gravida, previous abortion or miscarriage, previous cesarean sections, and placenta previa (all P<0.05), especially, previous cesarean sections (χ2=157.961) and placenta previa (χ2=91.759). Sonographic findings could be used to predict the degree of placental invasion especially the boundaries between placenta and uterine serosa, the boundary between placenta and myometrium, the disruption of the placental-uterine wall interface and loss of the normal retroplacental hypoechoic zone(all P<0.01). Conclusions Previous cesarean sections and placenta previa are the main independent risk factors associated with the degree of placenta implantation. Ultrasound could be used to make a prenatal suggestive diagnosis of placenta accreta spectrum disorders.

Objective:To design a novel electromagnetic ejection device for endoscopic suturing to achieve continuous deployment of suture nails.Methods:An electromagnetic ejection device and its accompanying suture nail structure were designed and a prototype was fabricated based on electromagnetic ejection principles. A finite element model of the electromagnetic ejection device was constructed to study the effects of armature-coil center distance and different driving voltages on suture nail ejection speed. An experimental platform for testing electromagnetic ejection velocity was constructed, and a high-speed camera was used to detect the ejection velocity. A platform for the suture embedding experiment was built to measure the effects of different voltages on the inserting speed of suture into the gastric wall tissue. A platform for a suture extraction force experiment was built to evaluate the extraction force of sutures embedded in tissues under different driving voltages.Results:A suture nail structure and electromagnetic ejection device were designed, and a prototype was fabricated. The ejection velocity increased and then decreased with the increase of the armature-coil center distance, and the maximum ejection velocity was 15.81 m/s at the center distance of 18 mm. At this distance, the voltage was linearly related to the ejection velocity, and the experimental values of the staple basically coincided with the simulated values. When the driving voltage was in the range of 150 to 180 V, the suture nails could successfully insert in the tissues, and the 180 V voltage group had a greater insertion depth. The extraction force of the suture nails at 120, 150, 180, and 210 V voltages were (0.49 ± 0.19), (1.14 ± 0.19), (1.23 ± 0.15), and (1.85 ± 0.31) N, respectively.Conclusions:A novel electromagnetic ejection device for endoscopic suturing is proposed that is capable of continuous firing of suture nails. This device provides a new long-distance driving method for intelligent, minimally invasive surgical instruments.