Segmented fast linear canonical transform.

Investigation of the discrete and fast linear canonical transforms is becoming one of the hottest research topics in modern signal processing and optics. How to handle and obtain the linear canonical frequency spectrum of very large input data based on equipment with limited memory space is one of the key problems. To focus on this problem, a new kind of segmented fast linear canonical transform has been proposed in this paper. First, the large data is segmented into short data. Thereby, the proposed algorithms can calculate very large input data and simultaneously keep the ideal frequency resolution. Second, the complexity of the derived algorithms has been analyzed in detail for different kinds of signals. Their performance with regard to resolution and precision are compared with the existing fast linear canonical transforms. Finally, experimental results are presented to verify the correctness of the results obtained.

[Evidence-based quality assessment of 10-year orthodontic clinical trials in 4 major dental journals].

OBJECTIVE: To assess the quality of orthodontic clinical trials published in 4 major dental journals in the past 10 years and establish the reference standard for orthodontic clinical trials and quality control of dental journals. METHODS: All the clinical trials published in Chinese Journal of Stomatology, West China Journal of Stomatology, Journal of Practice Stomatology and Chinese Journal of Orthodontics from 1999 to 2008 were searched. The demographic information of the papers was extracted and the quality of the clinical trials according to the consolidated standards of reporting trials (CONSORT) was assessed. RESULTS: Four hundred and ninety-four clinical trials were retrieved, and 21.3% (105/494) of them were supported by grants. For the study design, only 26.1% (129/494) were prospective studies, and 3.8% (19/494) were randomized clinical trials. It was hard to evaluate precisely due to the lack of information about the details of the study designs. For the randomized clinical trials, the lack of details for randomization, allocation concealment, blinding and intention to treat compromised the quality. CONCLUSIONS: The general quality of clinical trials in orthodontics is poor. It needs to be improved both in the clinical study design and the paper writing.

[Application of straight wire appliance for pre- and post-surgical orthodontics].

OBJECTIVE: To analyze the surgical patients treated with straight wire appliance for guidelines of clinical using of the appliance. METHODS: Totally 51 patients from Joint Clinic of Orthodontic Surgery, Peking University School of Stomatology with dentofacial deformities treated with straight wire appliance were analyzed. The patients were aged from 15 years to 34 years 5 months, average 18 years 9 months. Among whom, 16 are males, while the other 35 are females. RESULTS: Eighteen patients were treated with extraction of teeth, while other 33 cases were nonextraction case. The duration of average presurgical orthodontic treatment was 13.3 months, and 10.4 months was for postsurgical orthodontic treatment, totally active treatment time was 25.5 months. CONCLUSIONS: Straight wire appliance would benefit a lot for three dimensional control of teeth when doing pre- and post-surgical orthodontic treatment. Good results could be achieved without wire bending.