ObjectiveTo understand the latest progress of enrichment technology of circulating tumor cells (CTCs), and summarize the principle, advantages and disadvantages of various enrichment technologies and their applications in primary liver cancer (PLC). MethodThe literature relevant to the enrichment methods of CTCs in the PLC was reviewed and summarized. ResultsThe clinical significances of CTCs in the early diagnosis and staging, hierarchical diagnosis and treatment, and efficacy monitoring of patients with PLC had been recognized. There were many separation and enrichment technologies for CTC, which were mainly based on the differences of physical and biochemical characteristics, as well as the combination of enrichment methods with various principles. Each enrichment method had corresponding advantages and disadvantages, and few enrichment methods for CTC was applied to PLC. ConclusionsAlthough many problems need to be solved in enrichment method of CTCs at present, it is believed that the existing problems will be solved one by one with continuous improvement of technology. And CTC detection is expected to apply in clinical, so as to provide more efficient diagnosis and treatment methods for patients with PLC.
Photoplethysmography (PPG) is a non-invasive technique to measure heart rate at a lower cost, and it has been recently widely used in smart wearable devices. However, as PPG is easily affected by noises under high-intensity movement, the measured heart rate in sports has low precision. To tackle the problem, this paper proposed a heart rate extraction algorithm based on self-adaptive heart rate separation model. The algorithm firstly preprocessed acceleration and PPG signals, from which cadence and heart rate history were extracted respectively. A self-adaptive model was made based on the connection between the extracted information and current heart rate, and to output possible domain of the heart rate accordingly. The algorithm proposed in this article removed the interference from strong noises by narrowing the domain of real heart rate. From experimental results on the PPG dataset used in 2015 IEEE Signal Processing Cup, the average absolute error on 12 training sets was 1.12 beat per minute (bpm) (Pearson correlation coefficient: 0.996; consistency error: −0.184 bpm). The average absolute error on 10 testing sets was 3.19 bpm (Pearson correlation coefficient: 0.990; consistency error: 1.327 bpm). From experimental results, the algorithm proposed in this paper can effectively extract heart rate information under noises and has the potential to be put in usage in smart wearable devices.
ObjectiveTo investigate the preparation and osteogenic properties of poly (L-lactic acid)(PLLA)/lecithin porous scaffolds with open pore structure.MethodsPLLA/lecithin porous scaffolds with different lecithin contents (0, 5%, 10%, 20%, 30%, 40%, 50%) were prepared by thermally induced phase separation (groups A, B, C, D, E, F, and G, respectively). Scanning electron microscopy (SEM) was used to observe the surface morphology of the scaffolds. Wide-angle X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to detect the crystallinity of the scaffolds. The water uptake ability of the scaffolds was measured. The cell growth and viability of bone marrow mesenchymal stem cells (BMSCs) of mouse on each scaffold was assessed by cell counting kit 8 (CCK-8) method. The osteogenic differentiation ability of BMSCs on each scaffold was evaluated by alkaline phosphatase (ALP) activity. Finally, a critical-size rat calvarial bone defect model was used to evaluate the osteogenesis of the scaffolds in vivo. Micro-CT was used to reconstruct the three-dimensional model of the defect area, and the bone volume and bone mineral density were quantitatively analyzed.ResultsSEM results showed that the lecithin could slightly reduce the pore size; when lecithin content was 50%, platelet-like structure could be observed on the scaffolds. Wide angle XRD and DSC showed that the crystallinity of scaffolds gradually decreased with the increase of lecithin content. The water uptake ability test showed that the hydrophilicity of scaffolds increased with the increase of lecithin content. CCK-8 assay showed that cell activity gradually increased with the increase of culture time. After 7 days of culture, the absorbance (A) value of groups C, D, E, and F were significantly higher than that of groups A, B, and G (P<0.05), but no significant difference was found among groups C, D, E, and F (P>0.05). After 14 days of osteogenic induction, with the increase of lecithin content, there was a significant difference in ALP activity of each group. The ALP activity in groups D, E, F, and G were significantly higher than that in groups A, B, and C (P<0.05).In vivo, the results of Micro-CT examination and bone volume and bone mineral density showed that the scaffolds with 30% lecithin had the best repairing effect.ConclusionPrepared by thermally induced phase separation, the cytocompatibility, osteogenic differentiation, and bone repair ability of the PLLA/lecithin porous scaffold is obviously better than that of pure PLLA scaffold. PLLA/lecithin porous scaffold with suitable lecithin content is a promising scaffold material for bone tissue engineering.
Finite element method (FEM) was used to investigate the biomechanical properties of three types of surgical fixations of U-shaped sacral fractures. Based on a previously established and validated complete lumbar-pelvic model, three models of surgical fixations of U-shaped sacral fractures were established: ① S1S2 passed through screw (S1S2), ② L4–L5 pedicle screw + screw for wing of ilium (L4L5 + IS), and ③ L4–L5 pedicle screw + S1 passed through screw + screw for wing of ilium (L4L5 + S1 + IS). A 400 N force acting vertically downward, along with torque of 7.5 N·m in different directions (anterior flexion, posterior extension, axial rotation, and axial lateral bending), was exerted on the upper surface of L4. Comparisons were made on differences in separation of the fracture gap and maximum stress in sitting and standing positions among three fixation methods. This study showed that: for values of separation of the fracture gap produced by different operation groups in different positions, L4L5 + S1 + IS was far less than L4L5 + IS and S1S2. For internal fixators, the maximum stress value produced was: L4L5 + IS > L4L5 + S1 + IS > S1S2. For the intervertebral disc, the maximum stress value produced by S1S2 is much larger than that of L4L5 + S1 + IS and L4L5 + IS. In a comprehensive consideration, L4L5 + S1 + IS could be prioritized for fixation of U-shaped sacral fractures. The objective of this research is to compare the biomechanical differences of three different internal fixation methods for U-shaped sacral fractures, for the reference of clinical operation.
Blind source separation technique based on independent component analysis (ICA) can separate blood volume pulse (BVP) from the facial video and then realize the telemetry of heart rate, blood oxygen saturation, respiratory rate and other vital signs parameters. However, the superiority of ICA in BVP extraction has not been demonstrated in the existing researches. Some researchers suggested using traditional G-channel method for BVP extraction (G-BVP) instead of ICA method (ICA-BVP). This study investigated the applicability of ICA-BVP comparatively. To solve the inherent permutation problem of ICA, a spectral kurtosis-based method was proposed for BVP identification. The experimental results based on the facial video datasets from 9 subjects shows that ICA-BVP method has apparent advantages in motion artifacts attenuation and ambient light changes elimination. The kurtosis-based method achieved a good performance in BVP identification and dynamic heart rate (HR) estimation. In practical application, the proposed ICA-BVP method could present a better stability and accuracy in vital signs parameters extraction.
【Abstract】 Objective To summary the effects of staged pelvic closure using external fixator combined withreconstruction plate for old Tile B1 pelvic fracture. Methods From August 2000 to August 2006, 14 patients (9 males and 5 females, age ranging from 21 to 65 years with old Tile B1 pelvic fracture with pubic symphysis separation were treated. The injuries were caused by the traffic accident in 10 patients, high crash in 3, and crush in 1. The duration ranged from 4 weeks to 3 months. The 14 patients were compl icated with other injuries in some degrees. The X-ray and CT showed pubic symphysis separation. In 13 patients, pubic symphysis separation distance was more than 2.5 cm, who also had fracture or dislocation in the posterior structure of pelvis. The X-ray films showed the mean pubic symphysis separation distance was (6.67 ± 2.11) cm preoperatively. The 14 patients underwent pelvic external fixation at first and staged pelvic closure gradually for the pubic symphysis separation. After 2 to 3 weeks, when the pubic symphysis separation distance was less than 1 cm, the patients underwent open reduction and internal fixation with reconstruction plate. Pubic symphysis separation distance was measuredin the preoperative and postoperative pelvic anterioposterior X-ray films. The condition of the posterior structure of pelvis was observed in CT films. The functions of patients were assessed according to Majeed grading system. Results All incisions healed by first intention. The 14 patients were followed up for 6 months to 2 years (15 months on average). The X-ray films showed the mean pubic symphysis separation distance of post-operation was (0.85 ± 0.23) cm, showing statistically significant difference when compared with that of pre-operation (P lt; 0.05). The CT films showed fracture and dislocation of the posterior structure of pelvis had bony heal ing after 6 to 12 months. According to the Majeed grading system, the results were excellent in 5 cases, good in 4 cases, fair in 4 cases and poor in 1 case; the excellent and good rate was 64.29%. Conclusion Staged pelvic closure using external fixation combined with reconstruction plate for old pelvic fracture with pubic symphysis separation can reduce the pubic symphysis separation distance significantly. Satisfactory effects can be expected in treating the patients with TileB1 fracture.
In the present investigation, we studied four methods of blind source separation/independent component analysis (BSS/ICA), AMUSE, SOBI, JADE, and FastICA. We did the feature extraction of electroencephalogram (EEG) signals of brain computer interface (BCI) for classifying spontaneous mental activities, which contained four mental tasks including imagination of left hand, right hand, foot and tongue movement. Different methods of extract physiological components were studied and achieved good performance. Then, three combined methods of SOBI and FastICA for extraction of EEG features of motor imagery were proposed. The results showed that combining of SOBI and ICA could not only reduce various artifacts and noise but also localize useful source and improve accuracy of BCI. It would improve further study of physiological mechanisms of motor imagery.
The impulsive electroencephalograph (EEG) noises in evoked potential (EP) signals is very strong, usually with a heavy tail and infinite variance characteristics like the acceleration noise impact, hypoxia and etc., as shown in other special tests. The noises can be described by α stable distribution model. In this paper, Wigner-Ville distribution (WVD) and pseudo Wigner-Ville distribution (PWVD) time-frequency distribution based on the fractional lower order moment are presented to be improved. We got fractional lower order WVD (FLO-WVD) and fractional lower order PWVD (FLO-PWVD) time-frequency distribution which could be suitable for α stable distribution process. We also proposed the fractional lower order spatial time-frequency distribution matrix (FLO-STFM) concept. Therefore, combining with time-frequency underdetermined blind source separation (TF-UBSS), we proposed a new fractional lower order spatial time-frequency underdetermined blind source separation (FLO-TF-UBSS) which can work in α stable distribution environment. We used the FLO-TF-UBSS algorithm to extract EPs. Simulations showed that the proposed method could effectively extract EPs in EEG noises, and the separated EPs and EEG signals based on FLO-TF-UBSS were almost the same as the original signal, but blind separation based on TF-UBSS had certain deviation. The correlation coefficient of the FLO-TF-UBSS algorithm was higher than the TF-UBSS algorithm when generalized signal-to-noise ratio (GSNR) changed from 10 dB to 30 dB and α varied from 1.06 to 1.94, and was approximately equal to 1. Hence, the proposed FLO-TF-UBSS method might be better than the TF-UBSS algorithm based on second order for extracting EP signal under an EEG noise environment.
One of the key problems of brain-computer interfaces (BCI) is low signal-to-noise ratio (SNR) of electroencephalogram (EEG) signals. It affects recognition performance. To remove the artifact and noise, block under-determined blind source separation method based on the small number of channels is proposed in this paper. The non-stationary EEG signals are turned into block stationary signals by piecewise. The mixing matrix is estimated by the second-order under-determined blind mixing matrix identification. Then, the beamformer based on minimum mean square error separates the original sources of signals. Eventually, the reconstructed EEG for mixed signals removes the unwanted components of source signals to achieve suppressing artifact. The experiment results on the real motor imagery BCI indicated that the block under-determined blind source separation method could reconstruct signals and remove artifact effectively. The accuracy of motor imagery task of BCI has been greatly improved.
Objective To investigate the culture method forepidermal stem cells in vitro. Methods The epidermis was separated from the dermis, and shaken for 10 min in 0.05% trypsin at 37℃ to dissociate into single cells. Epidermal stem cells were selected by rapid attachment to collagen Ⅳ for 10-15 min and cultured on collagen Ⅳ or 3T3 feeder layer. All the cells were grown in DMEM without calcium, supplemented with 10% chelexed fetalbovine serum, 10 μg/L epidermal growth factor, 0.05 mmol/L CaCl2 and 0.8 mg/L hydrocortisone. Cultures were observed for colony formation under a phase constrast microscope. The phenotypes of epidermal stem cells were detected by flow cytometry and immunocytochemistry staining. Results The cells selectedby rapid adherence to collagen Ⅳ formed large colonies at 7～8 days, expressedK19 antigen. The percentages of cells at the G0 and G1 phases of the cell cycle and the percentage of α6briCD71dim cells in the experimental groups were higher than those in the control group. It indiciated that there was a significant difference between the experimental groups and the control groups(P＜0.05). ConclusionThe humanepidermal stem cells can be selected by rapid attachment to collagen Ⅳ, and they can be expanded in culture if the appropriate conditions are maintained.