Segmentation of bone surface from ultrasound using a lightweight network UBS-Net.

Objective. Ultrasound-assisted orthopaedic navigation held promise due to its non-ionizing feature, portability, low cost, and real-time performance. To facilitate the applications, it was critical to have accurate and real-time bone surface segmentation. Nevertheless, the imaging artifacts and low signal-to-noise ratios in the tomographical B-mode ultrasound (B-US) images created substantial challenges in bone surface detection. In this study, we presented an end-to-end lightweight US bone segmentation network (UBS-Net) for bone surface detection.Approach. We presented an end-to-end lightweight UBS-Net for bone surface detection, using the U-Net structure as the base framework and a level set loss function for improved sensitivity to bone surface detectability. A dual attention (DA) mechanism was introduced at the end of the encoder, which considered both position and channel information to obtain the correlation between the position and channel dimensions of the feature map, where axial attention (AA) replaced the traditional self-attention (SA) mechanism in the position attention module for better computational efficiency. The position attention and channel attention (CA) were combined with a two-class fusion module for the DA map. The decoding module finally completed the bone surface detection.Main Results. As a result, a frame rate of 21 frames per second (fps) in detection were achieved. It outperformed the state-of-the-art method with higher segmentation accuracy (Dice similarity coefficient: 88.76% versus 87.22%) when applied the retrospective ultrasound (US) data from 11 volunteers.Significance. The proposed UBS-Net for bone surface detection in ultrasound achieved outstanding accuracy and real-time performance. The new method out-performed the state-of-the-art methods. It had potential in US-guided orthopaedic surgery applications.

[Effect of piperine on metablism and distribution of nortriptyline in mice].

OBJECTIVE: To study the pharmacokinetics and brain/plasma concentration ratio of nortriptyline at multiple doses in mice which were pre-treated with physiological saline, piperine and verapamil. METHODS: A total of 216 male Kun Ming mice [(25±3) g] were equally divided into 4 groups randomly. Each group was intragastrically administered physiological saline (B), piperine (170 µg/ kg), piperine (5 mg/kg) and verapamil (5 mg/kg) for 8 days. On the 8th day, 1 h after giving the above drugs, each mice was intraperitoneally injected nortriptyline (13 mg/kg). The mice were sacrificed by picking off eyeballs at the time intervals of 5, 15, 30 min, and 1, 2, 4, 6, 8 and 12 h, and the cerebra were collected and weighted. Nortriptyline in mouse plasma and brain was determined by HPLC-MS/MS. The pharmacokinetic properties of the plasma, brain and brain/plasma were calculated. RESULTS: The AUC0-12 h of brain/plasma concentration ratio in the 170 µg/kg piperine group was significantly lower than that in the other groups (P<0.05), while the AUC0-12 h of brain/plasma concentration ratios in the 5 mg/kg piperine group and the verapamil group were not significantly different from those of untreated mice. CONCLUSION: Piperine (170 µg/kg) may induce P-glycoprotein expression in the blood-brain barrier, while piperines at 5 mg/kg has no influence on P-glycoprotein expression in the bloodbrain barrier.

[Comparison of conductivity-water content curve and visual methods for ascertaintation of the critical water content of O/W microemulsions formation].

This study is to screen 23 blank O/W type microemulsion (ME) samples, that is 15 samples from our laboratory, and 8 samples from literature; compare the conductivity-water content curve (CWCC) method and visual method in determining the critical water content during O/W type MEs' formation, to analyze the deficiency and the feasibility of visual method and to exploxe scientific meanings of CWCC method in judging the critical water content of O/W type MEs during formation. The results show that there is a significant difference between the theoretical feasible CWCC method and visual method in determining the critical water content (P<0.001), and the results judged by conductivity is higher than that by eye-based water content. Therefore, this article firmly confirmed the shortcomings of visual method and suggested that the eye-base "critical water content" may falls into continuous ME stage during O/W MEs' formation. Further more, the CWCC method has theoretical feasibility and scientific meanings in determining the critical water content of O/W type MEs during formation.