[Effects of 275 nm and 310 nm ultraviolet irradiation on bone metabolism in ovariectomized osteoporotic rats]

OBJECTIVE

To investigate the effect of 275 nm and 310 nm ultraviolet irradiation on ovariectomized rats' bone metabolism.

METHODS

Twenty four 3-month-old female Sprague-Dawley (SD) rat were randomly divided into control group, sham operated group, 275 nm ultraviolet (UV) irradiation group and 310 nm UV irradiation group. Each group contained 6 rats. The rats in the two irradiation groups were treated with bilateral ovariectomy. The rats in sham operated group received sham operation (They were given the same back incision and a bit of par-ovarian fat were removed). Control group received no disposition. About 24 weeks after operation, all the rats received detailed bone mineral density (BMD) detection again. Detection regions include cervical vertebra, lumbar vertebra, proximal femur, mid femur and distal femur. Next, osteopenia rats in 275 nm irradiation group were UV irradiated 275 nm with fixed illumination intensity (15 μW/cm²) everyday for 16 weeks. The osteopenia rats in 310 nm irradiation group were UV irradiated 310 nm with fixed illumination intensity (15 μW/cm²) everyday for 16 weeks. The backs of the rats were shaved regularly as irradiation area (6 cm×8 cm). After 16-week irradiation, all the rats' BMD of cervical vertebra, lumbar vertebra, proximal femur, mid femur and distal femur were measured. At the end of the trial, all the rats' blood specimens were obtained and serum 25(OH)D, procollagen type Ⅰ N-peptide (PINP) and osteocalcin (OC) were measured.

RESULTS

Compared with control group [(238.78±26.74) mg/cm³], the BMD of the whole body were significantly lower in 275 nm [(193.34±13.28) mg/cm³] and 310 nm [(191.19±18.48) mg/cm³] irradiation groups (P=0.002, P=0.001). There were no significant difference between sham operated group [(227.20±14.32) mg/cm³] and control group. After 16-week ultraviolet irradiation, the BMD of the whole body were significantly increased in 275 nm [(193.34±13.28) mg/cm³ vs. (221.68±25.52) mg/cm³, P=0.005] and 310 nm groups [(191.19±18.48) mg/cm³ vs. (267.48±20.54) mg/cm³, P < 0.001] after corresponding irradiation. The BMD of the four body regions (lumbar vertebra, proximal femur, mid femur and distal femur) had significantly increased after irradiation in 275 nm irradiation group. For 310 nm irradiation group, the BMD in cervical vertebra, lumbar vertebra, proximal femur, mid femur and distal femur also had increased significantly after 310 nm ultraviolet irradiation. The concentration of serum 25(OH)D and OC was higher in 275 nm irradiation group than in control group [(46.78±5.59) μg/L vs. (21.32±6.65) μg/L, P=0.002;(2.05±0.53) U/L vs. (1.32±0.07) U/L, P=0.022]. Compared with the control, the concentration of serum 25(OH)D [(58.05±12.74) μg/L], OC [(2.04±0.53) U/L] and PINP [(176.16±24.18) U/L] was significantly higher (P < 0.001, P=0.015, P=0.005) in 310 nm irradiation group. However, there were no significantly difference between sham operated group and the control.

CONCLUSION

Both 275 nm and 310 nm ultraviolet could improve rats' vitamin D synthesis. Both 275 nm and 310 nm ultraviolet could improve osteopenia rats' bone condition. The irradiation of 310 nm might be more effective on bone condition improvement.

[An arrhythmia classification method based on deep learning parallel network model]

OBJECTIVE

We propose a parallel neural network classification method to improve the performance of classification of 4 types of arrhythmias: normal beat, supraventricular ectopic beat, ventricular ectopic beat and fused beat.

METHODS

Preprocessing was performed including denoising of ECG signal, segmentation of small-scale heartbeat and large-scale heartbeat and data enhancement. Based on deep learning theory, densely connected convolutional network was applied to improve the limitation of waveform feature extraction, and bidirectional long short-term memory network and efficient channel attention network were combined to enhance the function of time series features and important features of the waveform. The parallel network structure was adopted, and the waveform features of small- scale heartbeat and large-scale heartbeat were input to improve the accuracy of arrhythmia classification at the same time. Softmax was used to carry out the 4 classification tasks of arrhythmia by the parallel network model.

RESULTS

The proposed method was verified using MIT-BIH Arrhythmia Database and 3 groups of experiments. The experiments for comparing the classification performance of multiple parallel network models and that of each classification model under different heartbeat input methods showed that the proposed classification model had an overall accuracy, average sensitivity and average specificity of 99.36%, 96.08% and 99.41%, respectively. Convergence performance analysis of the parallel network classification model showed that the training time of the classification model was 41 s.

CONCLUSION

The parallel multi-network classification method can improve the average sensitivity, specificity and training time while maintaining a high overall accuracy, and may thus provide a new technical solution for clinical diagnosis of arrhythmia.

[Feasibility of Delaire cephalometric analysis to predict the ideal sagittal position of the maxilla and chin for surgery-first patients in orthognathic surgery]

OBJECTIVE

There is no universally accepted method for determining the ideal sagittal position of the maxilla in orthognathic surgery. The purpose of this study was to compare how well the Delaire's cephalometric analysis correlated with postoperatively findings in patients who underwent orthognathic surgery planned using other cephalometric analyses, as well as to evaluate the feasibility of the Delaire's cephalometric analysis in predicting the ideal sagittal position of the maxilla and chin.

METHODS

In the study, 35 patients with skeletal Class III malocclusion were involved and met the criteria. Treatment plans were developed using photographs, 3-D photographs, radiographs, and standard cephalometric measurements. The Delaire's cephalometric analysis data, like the phase measurements (∠C1-L1 and ∠C1-L2) of the sagittal positions of the maxillary and the chin separating the reference line (L1) of NP point and the reference line (L2) of Me point, were analyzed using Dolphin Imaging software. At the same time, the analyses on standard measurements were also performed. Four orthognathic doctors, 4 orthodontic doctors and 4 college students from non-medical majors were selected as aesthetic evaluators to assess the patients' profile aesthetic by visual analogue scale (VAS). The results through the Delaire's cephalometric analysis were statistically compared with that through standard methods.

RESULTS

The mean of ∠C1-L1 was 83.93°±2.99° and∠C1-L2 was 89.08° ±2.48° for males postoperatively, and 85.67° ±3.60° and 88.30° ±4.20° for females postoperatively. Compared with the reference values of Chinese goodlooking people, there was no significant difference of NP point, whereas there was a significant difference of Me point. The postoperative aesthetic scores were: the mean was 6.71±0.25 of upper jaws, 6.81±0.30 of chins and 6.90±0.29 of the overall for males; and 7.19±0.22, 7.26±0.34 and 7.39±0.29 for females. Compared with preoperative scores, there was a significant improvement. Furthermore, the scores of chins and the overall scores were related to the sagittal position of the chins.

CONCLUSION

Compared with standard cephalometric analysis, the Deliare's cephalometric analysis well unravel the preoperative deformity and the final esthetic sagittal positions of maxillary and chin in the present sample, and could be a useful tool for the planning of surgery-first approach in orthognathic surgery.