Magnetotelluric Signal-Noise Identification and Separation Based on ApEn-MSE and StOMP.

Natural magnetotelluric signals are extremely weak and susceptible to various types of noise pollution. To obtain more useful magnetotelluric data for further analysis and research, effective signal-noise identification and separation is critical. To this end, we propose a novel method of magnetotelluric signal-noise identification and separation based on ApEn-MSE and Stagewise orthogonal matching pursuit (StOMP). Parameters with good irregularity metrics are introduced: Approximate entropy (ApEn) and multiscale entropy (MSE), in combination with k-means clustering, can be used to accurately identify the data segments that are disturbed by noise. Stagewise orthogonal matching pursuit (StOMP) is used for noise suppression only in data segments identified as containing strong interference. Finally, we reconstructed the signal. The results show that the proposed method can better preserve the low-frequency slow-change information of the magnetotelluric signal compared with just using StOMP, thus avoiding the loss of useful information due to over-processing, while producing a smoother and more continuous apparent resistivity curve. Moreover, the results more accurately reflect the inherent electrical structure information of the measured site itself.

[Visual evoked functional connectivity before and after smoking cessation based on functional magnetic resonance imaging].

OBJECTIVE: To explore differences in visual information processing for smoking addicts between before and after smoking cessation based on functional magnetic resonance imaging technology.
 Methods: Seventeen volunteers, with heavy dependence on nicotine, agreed to give up smoking and to complete the test. The primary visual network and secondary visual network were extracted by independent component analysis technology. The region of interest was defined as the region with significant difference between before and after smoking cessation. The functional connectivity analysis was carried out based on the selected region of interest.
 Results: After the subjects quitting smoking for 14 days, the increased functional connectivity was observed not only within secondary visual network but also between 2 interested networks; however, no functional connectivity was changed within primary visual network.
 Conclusion: The ability of visual information processing for smoking addicts could be significantly enhanced after 14 days of smoking cessation.

miR-33a functions as a tumor suppressor in melanoma by targeting HIF-1α.

BACKGROUND: Our previous findings showed that miR-33 expressed abnormally in clinical specimens of melanoma, but the exact molecular mechanism has not been elucidated. OBJECT: To determine miR-33's roles in melanoma and confirm whether HIF-1α is a direct target gene of miR-33a. METHODS: First miR-33a/b expression levels were detected in HM, WM35, WM451, A375 and SK-MEL-1. Then lentiviral vectors were constructed to intervene miR-33a expression in melanoma cells. Cell proliferation, invasion and metastasis were detected. A375 cells mice model was performed to test the tumorigenesis of melanoma in vivo. Finally the dual reporter gene assay was carried out to confirm whether HIF-1α is a direct target gene of miR-33a. RESULTS: MiR-33a/b exhibited a lower expression in WM35, WM451, A375 and SK-MEL-1 of the metastatic skin melanoma cell lines than that in HM. Then inhibition of miR-33a expression in WM35 and WM451 cell lines could promote cell proliferation, invasion and metastasis. Conversely, increased expression of miR-33a in A375 cells could inhibit cellproliferation, invasion and metastasis. In vivo tests also confirmed that overexpression of miR-33a in A375 cells significantly inhibited melanoma tumorigenesis. Finally, we confirmed that HIF-1α is a direct target gene of miR-33a. CONCLUSION: The newly identified miR-33a/HIF-1α axis might provide a new strategy for the treatment of melanoma.

miR-199a-5p regulates the expression of metastasis-associated genes in B16F10 melanoma cells.

MicroRNAs are regulatory factors that play important roles in tumor development, invasion and metastasis. Previously, we showed that miR-199a is abnormally expressed in clinical melanoma specimens and expression was closely associated with clinical features of metastasis. However, the exact molecular mechanisms by which miR-199a-5p influences melanoma invasion and metastasis remains unclear. In this study, we investigated gene expression changes of metastasis-associated genes in B16F10 melanoma cells following targeted silencing or overexpression of miR-199a-5p, using mouse tumor metastasis PCR arrays. Comparison of gene expression changes in miR-199a-5p-silenced versus overexpressing cells identified a set of upregulated genes (> 2-fold) including Cd44, Cdh1, Cxcr4, Etv4, Fxyd5, Rpsa, Mmp3, Myc, Rb1, Tcf20, Hprt1, Actb1 and downregulated genes (> 2-fold) including Ctsk, Itga7 and Tnfsf10. Regulation of a subset of these genes (Myc, Tnfsf10 and Cd44) following miR-199a-5p silencing or overexpression was validated by reverse transcription-polymerase chain reaction (RT-PCR) and western blot. In conclusion, our study demonstrates that miR-199a-5p regulates melanoma metastasis-related genes, and may provide a basis for the development of novel, molecularly targeted drugs.

[Particle swarm optimization fuzzy modeling and closed-loop anaesthesia control based on cerebral state index].

Due to individual differences of the depth of anaesthesia (DOA) controlled objects, the drawbacks of monitoring index, the traditional PID controller of anesthesia depth could not meet the demands of nonlinear control. However, the adjustments of the rules of DOA fuzzy control often rely on personal experience and, therefore, it could not achieve the satisfactory control effects. The present research established a fuzzy closed-loop control system which takes the cerebral state index (CSI) value as a feedback controlled variable, and it also adopts the particle swarm optimization (PSO) to optimize the fuzzy control rule and membership functions between the change of CSI and propofol infusion rate. The system sets the CSI targets at 40 and 30 through the system simulation, and it also adds some Gaussian noise to imitate clinical disturbance. Experimental results indicated that this system could reach the set CSI point accurately, rapidly and stably, with no obvious perturbation in the presence of noise. The fuzzy controller based on CSI which has been optimized by PSO has better stability and robustness in the DOA closed loop control system.

[Research progress on application of gold magnetic nanocomposite in biomedicine].

This paper provides a brief overview of the current research activities which focused on the bio-application of gold magnetic nanocomposite particles. By combining the magnetic characteristics of the iron oxide core with the unique features of nano-gold particles such as targeting by surface modification and optical properties, such composite nanoparticles have a wide range of applications in cancer hyperthermia, CT and MRI imaging, bio-separation, bio sensors, gene diagnosis, drug targeting and many other biomedical fields.

ERCC1 Cys8092Ala and XRCC1 Arg399Gln polymorphisms predict progression-free survival after curative radiotherapy for nasopharyngeal carcinoma.

BACKGROUND: Single nucleotide polymorphisms (SNPs) in DNA repair genes can alter gene expression and activity and affect response to cancer treatment and, correspondingly, survival. The present study was designed to evaluate the utility of the XRCC1 Arg399Gln and ERCC1 Cys8092Ala SNPs, measured in pretreatment biopsy samples, as predictors of response to radiotherapy in patients with non-metastatic nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: The study included 75 consecutive patients with stage II-IVA-B NPC. XRCC1 Arg399Glu and ERCC1 Cys8092Ala SNPs were identified from paraffin-embedded biopsy specimens via Sanger sequencing. Expression of p53 and pAkt protein was analyzed by immunohistochemical staining. Potential relationships between genetic polymorphisms and progression-free survival (PFS) were analyzed by using a Cox proportional hazards model, the Kaplan-Meier method, and the log-rank test. RESULTS: Multivariate analysis showed that carriers of the ERCC1 8092 Ala/Ala genotype [hazard ratio (HR) 1.882; 95% confidence interval (CI) 1.031-3.438; P = 0.039] and heavy smokers (≥20 pack-years) carrying the XRCC1 Arg/Arg genotype (HR 2.019; 95% CI 1.010-4.036; P = 0.047) had significantly lower PFS rates. Moreover, combined positive expression of p53 and pAkt led to significantly increased PFS in subgroups carrying the XRCC1 Gln allele (HR 7.057; 95% CI 2.073-24.021; P = 0.002) or the ERCC1 Cys allele (HR 2.568; 95% CI 1.056-6.248; P = 0.038). CONCLUSIONS: The ERCC1 Cys8092Ala polymorphism is an independent predictor of response to radiotherapy for NPC, and the XRCC1 Arg399Glu mutation combined with smoking status seems to predict PFS as well. Our results further suggest a possible correlation between these genetic polymorphisms and p53 protein status on survival.

Three-dimensional photoacoustic tomography based on graphics-processing-unit-accelerated finite element method.

Compared with commonly used analytical reconstruction methods, the frequency-domain finite element method (FEM) based approach has proven to be an accurate and flexible algorithm for photoacoustic tomography. However, the FEM-based algorithm is computationally demanding, especially for three-dimensional cases. To enhance the algorithm's efficiency, in this work a parallel computational strategy is implemented in the framework of the FEM-based reconstruction algorithm using a graphic-processing-unit parallel frame named the "compute unified device architecture." A series of simulation experiments is carried out to test the accuracy and accelerating effect of the improved method. The results obtained indicate that the parallel calculation does not change the accuracy of the reconstruction algorithm, while its computational cost is significantly reduced by a factor of 38.9 with a GTX 580 graphics card using the improved method.

Research on interpolation methods in medical image processing.

Image interpolation is widely used for the field of medical image processing. In this paper, interpolation methods are divided into three groups: filter interpolation, ordinary interpolation and general partial volume interpolation. Some commonly-used filter methods for image interpolation are pioneered, but the interpolation effects need to be further improved. When analyzing and discussing ordinary interpolation, many asymmetrical kernel interpolation methods are proposed. Compared with symmetrical kernel ones, the former are have some advantages. After analyzing the partial volume and generalized partial volume estimation interpolations, the new concept and constraint conditions of the general partial volume interpolation are defined, and several new partial volume interpolation functions are derived. By performing the experiments of image scaling, rotation and self-registration, the interpolation methods mentioned in this paper are compared in the entropy, peak signal-to-noise ratio, cross entropy, normalized cross-correlation coefficient and running time. Among the filter interpolation methods, the median and B-spline filter interpolations have a relatively better interpolating performance. Among the ordinary interpolation methods, on the whole, the symmetrical cubic kernel interpolations demonstrate a strong advantage, especially the symmetrical cubic B-spline interpolation. However, we have to mention that they are very time-consuming and have lower time efficiency. As for the general partial volume interpolation methods, from the total error of image self-registration, the symmetrical interpolations provide certain superiority; but considering the processing efficiency, the asymmetrical interpolations are better.

Medical image registration using fuzzy theory.

Mutual information (MI)-based registration, which uses MI as the similarity measure, is a representative method in medical image registration. It has an excellent robustness and accuracy, but with the disadvantages of a large amount of calculation and a long processing time. In this paper, by computing the medical image moments, the centroid is acquired. By applying fuzzy c-means clustering, the coordinates of the medical image are divided into two clusters to fit a straight line, and the rotation angles of the reference and floating images are computed, respectively. Thereby, the initial values for registering the images are determined. When searching the optimal geometric transformation parameters, we put forward the two new concepts of fuzzy distance and fuzzy signal-to-noise ratio (FSNR), and we select FSNR as the similarity measure between the reference and floating images. In the experiments, the Simplex method is chosen as multi-parameter optimisation. The experimental results show that this proposed method has a simple implementation, a low computational cost, a fast registration and good registration accuracy. Moreover, it can effectively avoid trapping into the local optima. It is adapted to both mono-modality and multi-modality image registrations.

Platycodon grandiflorum induces apoptosis in SKOV3 human ovarian cancer cells through mitochondrial-dependent pathway.

Platycodon grandiflorum (Jacq.) A. DC., a Chinese food and medicine, has been used as expectorant traditionally. The present study aimed to investigate the effect of Platycodon grandiflorum extract (PGE) on SKOV3 ovarian cancer cells. 3-(4,5- dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay was used to monitor cell numbers, Annexin-V/propidium iodide (PI) staining, RT-PCR and Western blot were used to examine cell apoptosis, caspases activation. Bcl-2 and Bax expressions and mitochondrial cytochrome c release. Our result showed that PGE-induced apoptosis was associated with activation of caspase-3, -8 and -9, down-regulation of Bcl-2, up-regulation of Bax and release of mitochondrial cytochrome c to cytosol. The data indicate that PGE may have anti-tumor effect mainly via caspase-3 and caspase-9 dependent apoptotic pathway.

An LC-MS/MS method for determination of forsythiaside in rat plasma and application to a pharmacokinetic study.

A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of forsythiaside in rat plasma using epicatechin as internal standard. The analytes were extracted by solid-phase extraction and chromatographied on a C(18) column eluted with a gradient mobile phase of acetonitrile and water both containing 0.2% formic acid. The detection was performed by negative ion electrospray ionization in multiple reaction monitoring mode, monitoring the transitions m/z 623-->161 and m/z 289-->109 for forsythiaside and epicatechin, respectively. The assay was linear over the concentration ranges of 2.0-50.0 and 50.0-5000.0ng/mL with limits of detection and quantification of 0.2 and 1.0ng/mL, respectively. The precision was <10.8% and the accuracy was >91.9%, and extraction recovery ranged from 81.3% to 85.0%. This method was successfully applied to a pharmacokinetic study of forsythiaside in rats after intravenous (20mg/kg) and oral (100mg/kg) administration, and the result showed that the compound was poorly absorbed with an absolute bioavailability being approximately 0.5%.

[Feature detection of tissue lesion in HIFU based on SOM].

Noninvasive detection of tissue lesion is an important aided way in the process of high intensity focused ultrasound (HIFU) treatment. A new method is proposed for noninvasive detection of tissue lesion based on self-organizing maps (SOM) network. Tissue lesion, created by HIFU exposures, inevitably leads to change in B-mode image, since some new interfaces will appear in tissue. The difference-sub-image near focus of HIFU, where the tissue lesion appears, is used. Feature of lesion in difference-sub-image is extracted using the method based on SOM network. Experimental results show that the performance of the method proposed in this paper is better than that of others, such as the methods based on average gray, energy and standard deviation of difference-sub-image.

[Dosimetric verification and clinical efficacy of intensity modulated radiotherapy in nasopharyngeal carcinoma].

OBJECTIVE: To investigate dosimetric characteristics and to evaluate the clinical efficacy of intensity modulated radiotherapy (IMRT) as compared with conventional radiotherapy in nasopharyngeal carcinoma (NPC). METHODS: Forty-seven NPC patients who accepted IMRT served as the IMRT group, and conventional radiotherapy plan was also made for each patient in this group using the treatment planning system. Dosiological evaluation of the 2 radiotherapy plans was made through dose volume histogram, 95% target volume dose (V(95)) and normal tissue complication probability. Another 47 patients who underwent conventional radiotherapy (CRT) at the same period formed the control group. The therapeutic effect as well as the acutes and late toxicities of normal tissues in the 2 groups were observed. RESULTS: V(95) of the IMRT was more than 96% (96.83%-99.99%) for each target area, obviously superior to CRT in the sub-clinical target area. The radiation dose of normal tissues such as the brainstem and the spinal cord in the IMRT was much less than that in the CRT. Consistant with this, the part and complete remission rate, the 3-year loco-regional progress free survival rate, and overall survival rate in the IMRT group were all higher than those in the CRT group. For most patients in the IMRT group, the grade of acute toxicities was much lower than that in the CRT group. Patients in the IMRT group showed no more than grade 3 xerostomia, while in the CRT group still 21% of the patients suffered grade 3 or higher xerostomia a year later. CONCLUSION: Compared with CRT, IMRT can improve the target volume dose and decrease the dose of surrounding tissues, resulting in higher control rate and fewer side effects.

[Alternating magnetic field damages the reproductive function of murine testes].

OBJECTIVE: To explore the relationship between physical and biological effects of alternating magnetic field and study the influence of the magnetic field on the reproductive function of murine testes. METHODS: Thirty ICR mice were randomized into 5 groups: normal control, X-ray radiation, weak magnetic field (1000 Hz), 1 h strong magnetic field and 2 h strong magnetic field (2000 Hz). The mice were sacrificed at 7 days after the exposure for the analysis of testicular sperm motility, observation of histopathological changes in the testis by HE staining and evaluation of the changes by modified Johnsen grade criteria. RESULTS: The rates of sperm motility were (42.37 +/- 10.24)% in the normal control group, (39.00 +/- 12.35)% in the X-ray radiation group, (36.00 +/- 17.28)% in the weak magnetic field group, (10.72 +/- 5.67)% in the 1 h strong magnetic field group and (4.44 +/- 2.87)% in the 2 h strong magnetic field group, respectively. Johnsen's scores decreased and the testis damage increased in a dose- and time-dependent manner. CONCLUSION: Magnetic field, either strong or weak, may damage the testis function by inducing injury to seminiferous tubules and Leydig cells, thickening of the basal membrane, derangement, exfoliation, massive apoptosis and necrosis of spermatogenic cells in the lumen, situation of the epididymis, and consequently the absence of sperm.

[Removal of ocular artifact from EEG based on JADE].

The method of Joint approximate diagonalization (JADE) is used to remove the ocular artifact from Electroencephalogram (EEG). As the JADE algorithm can be used to separate sub-gaussian and super-gaussian sources, it is possible to extract the signals that are statistically independent, and to identify the spatial map that is associated with the artifactual component. Thus the method can remove artifactual component. Satisfactory results illustrate the robust and practicability of the algorithm.

[Effect of early rehabilitation training on radiation-induced trismus in nasopharyngeal carcinoma patients].

BACKGROUND & OBJECTIVE: Many nasopharyngeal carcinoma (NPC) patients could survive for a long time after radiotherapy. But the complications of radiotherapy, such as trismus, severely influence the quality of life of NPC patients. This study was to observe the effect of early rehabilitation training on radiation-induced trismus of NPC patients. METHODS: A total of 108 NPC patients received rehabilitation guidance by doctors at initial radiotherapy and subjected to early rehabilitation training regularly and intensively after radical radiotherapy between Dec. 2003 and Dec. 2004 at Xiangya Hospital of Central South University. They continued on rehabilitation training out of hospital as the same in hospital. According to the data of rehabilitation training obtained by questionnaire at 1 month after radiotherapy, the patients who completed the amount of rehabilitation training (>or=75%) were brought into rehabilitation training group, the others was brought into control group. The distance between two dens incivus medialis (DDIM) of the patients was measured at 1 month and 1 year after radiotherapy. RESULTS: The difference of rehabilitation training score was significantly higher in rehabilitation training group than in control group (9.80+/-3.02. vs.4.75+/-1.90 at 1 month after radiotherapy, P<0.05û 9.00+/-2.67 vs. 2.20+/-0.82 at 1 year after radiotherapy, P<0.05). The occurrence rates of trismus were 44.1% at 1 month and 51.5% at 1 year after radiotherapy in rehabilitation training group, and 60.0% and 85.0% in control group. The reduction of DDIM was significantly smaller in rehabilitation training group than in control group [(0.50+/-0.48) cm vs. (1.20+/-0.74) cm at 1 month after radiotherapy, P<0.05û (0.58+/-0.62) cm vs. (2.42+/-0.84) cm at 1 year after radiotherapy, P<0.01]. CONCLUSIONS: Early rehabilitation training is helpful to decrease the occurrence of trismus in NPC patients after radiotherapy and improve the quality of life of NPC patients.

[Design of a cardiac monitoring system using mobile communications].

Telemedicine is gaining more and more momentum as a new approach for patients'surveillance. In many monitoring parameters, electrocardiography is the most important, especially for monitoring patients with serious cardiovascular diseases. They need to be monitored frequently in order to detect any deterioration. In this paper,we design a electrocardiographic telemetry system using General Packet Radio Service(GPRS). This design adds to traditional Holter capability of monitoring the patients'heart anywhere, anytime.