To enhance speech recognition, as well as Mandarin tone recognition in noice, we proposed a speech coding strategy called zero-crossing of fine structure in low frequency (LFFS) for cochlear implant based on low frequency non-uniform sampling (LFFS for short). In the range of frequency perceived boundary of human ear, we used zero-crossing time of the fine structure to generate the stimulus pulse sequences based on the frequency selection rule. Acoustic simulation results showed that although on quiet background the performance of LFFS was similar to continuous interleaved sampling (CIS), on the noise background the performance of LFFS in Chinese tones, words and sentences were significantly better than CIS. In addition to this, we also got better Mandarin recognition factors distribution by using the improved index distribution model. LFFS contains more tonal information which was able to effectively improve Mandarin recognition of the cochlear implant.
ObjectiveTo study the effect of inhibitor of differentiation 1 (Id1) gene transfection on bone morphogenetic protein 2 (BMP-2) promoting the expressions of collagen type Ⅱ (COL Ⅱ) and aggrecan (ACAN) in intervertebral cartilage endplate cells (EPCs). MethodsEPCs were harvested from the New Zealand white rabbits, the 2nd generation EPCs were used for experiment. The transfection efficiency of green fluorescent protein blank lentivirus, high expression of Id1 lentivirus, RNA interference (RNAi) Id1 lentivirus transfection in the EPCs were observed by the fluorescence microscopy, real-time fluorescence quantitative PCR, and Western blot. Blank vector, single BMP-2 gene, BMP-2 and Id1 genes were transfected into EPCs, respectively. The cell morphology and the expressions of COL Ⅱ and ACAN in each group were observed. ResultsLentiviral transfection had no significant effect on the cell morphology. The EPCs were effectively transfected by the high expression Id1 lentivirus and RNAi Id1 lentivirus; the expression of Id1 mRNA was also significantly interfered. The expressions of COL Ⅱ and ACAN mRNA and synthesis of COL Ⅱ and ACAN protein were significantly higher in BMP-2 lentivirus and high expression Id1 lentivirus groups than control group (P<0.05). The expression of COL Ⅱ and ACAN protein were down regulated in the cartilage endplate cells when the expression of Id1 gene was decreased (P<0.05). ConclusionUp-regulation of Id1 gene expression can enhance the effects of BMP-2 on the synthesis of COL Ⅱ and ACAN in EPCs.
Objective To review the research background, biomechanical characteristics, and clinical application of fenestrated pedicle screw (FPS). Methods The recent literature about the study and application of FPS was reviewed, analyzed, and summarized. Results Compared with the technique of conventional pedicle screw augmentation, FPS can be augmented with polymethyl methacrylate (PMMA) through inner central pore and side holes. Hence, the augmentation process of FPS is more convenient during operation. The biomechanics of PMMA augmented FPS is strong enough for instrumentation in osteoporotic vertebra body and the way of FPS PMMA augmentation can reduce the risk of PMMA leakage. Conclusion FPS is an innovation in the technology of spinal instrumentation, which is expected to improve the clinical outcome of PMMA augmented pedicle screw in osteoporotic vertebra body fixation.