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2012 Vol. 31, No. 1
Published: 2012-02-20
 
1 Diagnosis of Congestive Heart Failure Based on BP Network with Multiple Heart Rate Variability Parameters
HOU FengZhen1, 2 HUANG XiaoLin1    NING XinBao1*
DOI: 10.3969/j.issn.0258-8021.2012.01.01
Information delivered by a single heart rate variability (HRV) index is inadequate and it is very difficult to completely classify the congestive heart failure (CHF) patients from healthy people by using a single index. Artificial neural network，inspired by biological nervous systems, is composed of simple elements operating in parallel and open up very broad vistas in the field of pattern recognition. Based on composing timedomain analysis, frequencydomain analysis and nonlinear analysis of HRV signals, several indices were extracted as the feature parameters for the diagnosis of CHF. Then BP network was trained and applied to the diagnosis of congestive heart failure. After 10000 times of training, validating and testing, the optimal recognition rate achieved 99.14% with 86.97% on average. The results suggest that the conjunctive application of linear and nonlinear methods of HRV can extract more information underlying the complex dynamic systems.
2012 Vol. 31 (1): 1-6 [Abstract] ( 274 ) HTML (1 KB)  PDF (381 KB)  ( 417 )
7 Pattern Recognition of Surface Electromyography Signal Based on Multi-Scale Maximal Lyapunov Exponent
ZOU Xiao Yang     LEI Min*
DOI: 10.3969/j.issn.0258-8021.2012.01.002
To increase the recognition accuracy of action surface electromyography (SEMG) signal, a method combining the maximal Lyapunov exponent and multiscale analysis was proposed. Considering the nonlinear and nonstationary characteristic of SEMG, a multi-scale maximal Lyapunov exponent (MSMLE) feature was introduced and applied to the pattern recognition of six types forearm action SEMG signals. First step was to decomposite original signal using HilbertHuang transform (HHT), known as multiscale decomposition. Then, MSMLE was calculated by nonlinear time series analysis method. At last, eigenvector MSMLE was input into support vector machine (SVM) for recognition. The mean recognition accuracy reached 97.5%, which was 3.9% greater than that obtained from maximal Lyapunov exponent of original signal. Results showed that the proposed method was effective and precise in the pattern recognition of action SEMG signals.
2012 Vol. 31 (1): 7-12 [Abstract] ( 332 ) HTML (1 KB)  PDF (534 KB)  ( 760 )
13 Modeling and Simulation of a Fifth-Order Lumped Parameter Cardiovascular System
LIU LingLing1*LI Lan2    QIAN Kun Xi 1
DOI: 3969/j.issn.0258-8021.2012.01.003
In order to deeply understand the mechanisim of heart failure and provide therapy and simulation tool for clinical diagnosis and treatment, a fifth-order lumped parameter cardiovascular system model according to electrical circuit theory was built in this paper. Using MATLAB, the simulation results show that the model is effective and it can simulate the hemodynamics of normal heart. The simulated CO (Cardiac Output) is 5.12 L/min. Under different level exercises including mild exercise, moderate exercise and severe exercise, of normal heart  the simulated CO gradually increase from 5.09 L/min, 8.86 L/min, 10.74 L/min to 14.7 L/min. The four categories of ClassⅠ, ClassⅡ, ClassⅢ, Class Ⅳ of heart failure can be also simulated by the method. The simulated CO decrease from 5 L/min, 4.4 L/min, 3.8 L/min to 3.2 L/min. The results of our studies agreed well with real physiological conditions and the experimental data reported in literatures. This is important for the diagnosis and treatment of heart diseases.
2012 Vol. 31 (1): 13-19 [Abstract] ( 337 ) HTML (1 KB)  PDF (870 KB)  ( 1125 )
20 The Spectrum of Ultrasound Echo Signal from Ocular Tissue
ZHAO ZhiHui     LIN YiCong     ZHENG Zheng*
DOI: 10.3969/j.issn.0258-8021.2012.01.004
The spectral parameters of echo signals from eyes are critical for designing the receiving filter of the ophthalmological ultrasound device. It is inappropriate to estimate the echo spectra of the eyes with the averaged acoustic attenuation coefficient derived from soft tissues, because the ocular tissues are far from uniform. This paper studies the echo spectrum from human eyes 〖WTBX〗in vivo〖WTBZ〗. A 10 MHz ultrasonic transducer is used to scan the human eye and the result shows that the center frequencies of echo signal from eyeball are almost unchanged from the lens till retina, but decline rapidly with the depth about 3~5 mm behind the fundus from retina with the average slope about -0.16 MHz/mm. When the contributions of the probe and electronic elements are eliminated, the remaining spectrum of the posterior lens capsule is relatively flat which is similar to the feature of a plane reflector with high reflectivity, while the remaining spectrum of fundus present an ascending trend with the frequency, which is close to the characteristic expected for Rayleigh scatters.
2012 Vol. 31 (1): 20-24 [Abstract] ( 235 ) HTML (1 KB)  PDF (608 KB)  ( 358 )
25 Hard Plaque Characteristics Based Media-Adventitia Border Detection in Intravascular Ultrasound Images
XING Dong1   YANG Feng1*HUANG Jing1     TU ShengXian2      DIJKSTRA Jouke2
DOI: 10.3969/j.issn.0258-8021.2012.01.005
This paper presents a new approach for the detection of media-adventitia border in intravascular ultrasound (IVUS) images, to overcome problems of hard plaque and acoustic shadow which make mediaadventitia difficult to detect. The approach started with image classification using k-means algorithm, such that the region of hard plaques was delineated from the IVUS image. In a next step, a cost matrix was created by combining image gradient, hard plaque location and image intensity. A heuristic graph-searching was then applied to find the media-adventitia border from the cost matrix. Experiment results showed that the approach improved the accuracy of media-adventitia border detection by overcoming problems caused by acoustic shadow and hard plaque inhomogeneity, and the correct rate reached 95.57%.
2012 Vol. 31 (1): 25-31 [Abstract] ( 217 ) HTML (1 KB)  PDF (1048 KB)  ( 670 )
32 A Visual Mechanism Inspired Model for Image Segmentation
DU Xin Yu   LI Yong Jie     YAO De Zhong*
DOI: 10.3969/j.issn.0258-8021.2012.01.006
In this paper, a multiscale Markov random field (MRF) model in the wavelet domain was proposed by simulating several image segmentation functions of the visual system. Human visual system (HVS) has feature detection ability, hierarchy, bidirectional connection, and self-learning mechanisms. For an input scene, our model provided its sparse representations using wavelet transforms (WT) to mimic the feature detection ability, and used pyramid framework to mimic hierarchy. In the framework of the model, there were two information flows that were used to mimic bidirectional connection, i.e., a bottom-up procedure to extract input features and a top-down procedure to provide feedback controls. In addition, the iteration in procession was the simulation of selflearning mechanisms, and the multiscale MRF was the tool for image segmentation. The quality of the framework was tested and compared to some classic image segmentation algorithms. Results showed that the proposed model obtained improved data than those obtained by classic image segmentation algorithms.
2012 Vol. 31 (1): 32-38 [Abstract] ( 316 ) HTML (1 KB)  PDF (902 KB)  ( 510 )
39 Research on Heart Sounds Signal Based on Wavelet Transform and Empirical Mode Decomposition
GUO Xing Ming*    YUAN Zhi Hui
DOI: 10.3969/j.issn.0258-8021.2012.01.007
In order to solve the problem of end effect in empirical mode decomposition (EMD), this paper proposed method of extracting the features of heart sounds signal through empirical mode decomposition after wavelet denoising. A new method of data extending based on self - adaptive waveform matching was established for EMD. With wavelet denoising, the influence of useless frequency component on the later decomposition was decreased, thus effectively reduced the decomposition layers of the EMD. The self-adaptive waveform matching extending method considered both inner characteristics of signal and variation tendency of endpoint, hence it is more reasonable compared with the conventional extending method. Decompose 40 cases of heart sounds signal with the method, the location of the first and second heart sound was identified by explicit double threshold, the detection rate of S1 was up to 97.05%, and that of S2 was 97.12%. The result indicated that the proposed method could solve the end issue effectively, the speed and accuracy of the EMD were improved.
2012 Vol. 31 (1): 39-44 [Abstract] ( 349 ) HTML (1 KB)  PDF (903 KB)  ( 863 )
45 A Classification Method for RNA Splicing Regulatory Elements
MA Meng1,2*WANG Yang1   RU Ying3    WANG Ze Feng1*
DOI: 10.3969/j.issn.0258-8021.2012.01.008
The sequence classification methods have broad application in various bioinformatics areas such as the identification of regulatory elements of transcription and the prediction of protein structure. Here we presented a new classification method to analyze short sequences based on their sequential features, and used this method to study RNA splicing regulatory elements. This method extracted the sequential features from the known spicing regulatory elements, and developed a scoring system to evaluate how possible a given short sequence can regulate RNA splicing. This method was compared with some other methods through applying to a set of exonic splicing enhancer (ESE) and silencer (ESS) octamers. The average prediction accuracy of this sequential feature-based method for three kinds of computation validation experiments reached about 93% and the transparent predictive structure of the method helps to interpret the biological mechanism. This paper shows a new method for biology series’ data analysis and presents a new way for the study of regulatory sequences that control gene expression.
2012 Vol. 31 (1): 45-52 [Abstract] ( 366 ) HTML (1 KB)  PDF (733 KB)  ( 426 )
53 Forward Problem Simulation in Magnetic Induction Tomography -Based on Galerkin Finite Element Method
KE Li*    PANG Pei Pei    DU Qiang
DOI: 10.3969/j.issn.0258-8021.2012.01.009
Forward problem solution in magnetic induction tomography (MIT) can provide significant basis to system modeling, because MIT differential equation is nonpositivedefinite, which increases calculative complexity. The paper designed a method based on Galerkin Finite Element (GFE) that had no special requirement about differential operator. The GFE solved the non-positive-definite problem of eddy current field, the method was used to analyze accurately the magnetic field distribution, eddy current intensity and phase shift in detecting coils. The result demonstrated that magnetic flux density amplitude was mainly decided by real part and imaginary was sensitive to conductivity change, thus the imaginary of magnetic flux density could be used to reconstruct image. At the same time, the phase shift in the detecting coil was investigated. The result showed that the phase shift of detecting coil increased as it closed to object or was far away from exciting coil. To the same position of the object, the phase shift in detecting coil was linear to the conductivity. The theoretical derivation and the simulated experiment verified that the GFE method used in the paper was effective to solve the MIT forward problem, and further more it could provide the experiment reference and theoretical verification to MIT hardware system measurement and reconstruction algorithm study.
2012 Vol. 31 (1): 53-58 [Abstract] ( 327 ) HTML (1 KB)  PDF (996 KB)  ( 665 )
59 A Novel Evaluation Criterion for the Discrimination of Features and its Application in the Diagnosis of Erythemato-Squamous Disease#br#
XIE Juan Ying1, 2*LEI Jin Hu1     XIE Wei Xin2, 3
DOI: 10.3969/j.issn.0258-8021.2012.01.010
In order to overcome the disadvantages of F-score which does not take into account the influence of different measure for features on the discrimination of each feature between classes, a new criterion referred to as D-score was presented in this paper for measuring the discrimination of sample features between classes without any affection come from different unit of each feature. The D-score criterion was combined with Sequential Forward Search (SFS) strategy and Sequential Forward Floating Search (SFFS) strategy, respectively, to select features, whilst Support Vector Machines (SVM) is used as a classification tool to guide feature selection by evaluating the performance of the selected feature subset in classification, so that the two new hybrid feature selection methods were proposed combining the advantages of filters and wrappers, and were applied to dermatology dataset from UCI machine learning repository to find the key features of diagnosing erythematosquamous disease to help doctors make right decisions. Tenfold cross validation experiments have been conducted to compare the performance of D-score and our previously improved F-score in evaluating the discriminability of features between classes in diagnosing erythematosquamous disease. Experimental results showed that the D-score criterion was much more effective than the improved F-score, and obtained a preferable effect in the diagnosis of erythematosquamous disease with the improvement of 1.11％ in accuracy via SFS search strategy; and about 3.00% improvement in minimum accuracy among 10 folds and around 0.3% improvement of average accuracy using SFFS search strategy as well as the best accuracy of 100%. The common features among 10 folds selected via D-score with SFFS was a subset of that of the improved F-score combined with SFFS.
2012 Vol. 31 (1): 59-67 [Abstract] ( 527 ) HTML (1 KB)  PDF (639 KB)  ( 353 )
68 The Study of Extraction Methods of Dental Three-Dimensional Features Based on Improved Discrete Curve Evolution
YANG Ling1,2LI Yu2      WANG ZhongKe3       RAO NiNi 1*
DOI: 10.3969/j.issn.0258-8021.2012.01.011
Extraction of tooth feature points effectively is of significance for the subsequent three-dimensional registration and reconstruction. However, the efficiency of current calculation methods is low. This work improved discrete curve evolution (DCE) algorithm and used characteristic factor of curve (CFOC) to describe the complexity of contour on each dental CT slice. With the adaptive CFOC, the feature points number in curves in different slices could be determined, thus the redundancy in the stored data was reduced, improving the extraction efficiency of feature points. The improved DCE algorithm was used for exacting the feature points from different clinical CT slices, comparing experimental results with that of the conventional DCE algorithm. The results showed that the improved method saved nearly half of time that the conventional method required for extracting feature points from each CT slice, and the feature points  number extracted by the improved method is approximately four fifths of that of the conventional method. After cubic spline interpolation with different ratios of the feature points from different slices, the slice images were reconstructed and the reconstruction results reflected the true structure of the teeth. Therefore, the calculation efficiency of the improved method is much higher than that of the conventional DCE algorithm.
2012 Vol. 31 (1): 68-74 [Abstract] ( 394 ) HTML (1 KB)  PDF (694 KB)  ( 801 )
75 Generalized Kernel Linear Discriminant Analysis for Brain Computer Interface
WANG Jin Jia* HU Bei
DOI: 10.3969/j.issn.0258-8021.2012.01.012
According to the signal processing of EEG in brain-computer interface (BCI), a generalized kernel linear discriminant analysis (GKLDA) method based on kernel method and generalized singular value decomposition (GSVD) was proposed to extract feature of EEG with two classes. First, the samples were mapped using the linear discriminant analysis in the feature space defined by a nonlinear mapping through kernel functions. Secondly, a nonlinear spatial filtering was solved through the GSVD which can solve the small sample size problem. In the experiment, the GKLDA was contrasted with kernel common spatial pattern (KCSP), kernel linear discriminant analysis (KDA) and generalized linear discriminant analysis (GDA) for three public data which are dataset of BCI Competition Ⅰ, dataset Ⅳ of BCI Competition Ⅱ and S4b in dataset ⅢIB of BCI Competition Ⅲ. The same method was used on the dataset from ourselves with the fisher linear discriminant analysis classifier. The accuracy of the propose GKLDA feature of the three data are 93%,77%,80%, and 97% on the dataset from ourselves, better than the other kernel method. Experiment results indicate that, the GKLDA method can be well a new effective feature extraction method in brain computer interface.
2012 Vol. 31 (1): 75-82 [Abstract] ( 363 ) HTML (1 KB)  PDF (1373 KB)  ( 510 )
83 Study on  Intelligent Control of Human Body Prosthetic Leg Based on Fuzzy-CMAC
YU HongLiu1*XU Zhao Hong1    LU BoRui1      ZHANG Ding  Guo2
DOI: 10.3969/j.issn.0258-8021.2012.01.013
To meet the need of parameter personalization and walking speed variance of patients, leg prostheses have parameter systems with complex features including nonlinearity and parameter uncertainty, however conventional mathematic models can not meet the demand for the actual control because the IPL knee torque is indirectly caused by the nonlinear damping at the knee joint. Hence intelligent prosthetic leg (IPL) system is required. In this work a dynamic model of selfmade hydraulic IPL with the nonlinear damper control parameters and hip torque was established, and an inverse dynamic compound controller of PD-FCMAC for tracking the knee swing was designed. A case simulation showed that an arbitrary trajectory could  be tracked in less than 5 s, which proved that the designed controller had high real-time performance  with good precision.
2012 Vol. 31 (1): 83-88 [Abstract] ( 358 ) HTML (1 KB)  PDF (941 KB)  ( 503 )
89 Numerical Simulation on Characteristics of Airflow Movement in Human Upper Respiratory Tract under Fluid-Solid Coupling
SUN Dong   LI Fu  Sheng  XU XinXi*       ZHAO XiuGu     TAN ShuLin
DOI: 10.3969/j.issn.0258-8021.2012.01.014
Research the effect of fluidsolid coupling on human upper respiratory tract can lead to deep understanding of the characteristics of the airflow in human upper respiratory tract and plays a very important role in analyzing the diffusion, transition and deposition patterns of aerosol in human upper respiratory tract. The numerical simulation of fluid-solid interaction mechanics was applied to simulate airflow movement in human upper respiratory tract model in the conditions of low intensive respiratory patterns (respiratory flow is 30 L/min), the shape variation and shear stress distribution in human upper respiratory tract was discussed, and the airflow movement in human upper respiratory tract was analyzed. Results showed that in the low intensive respiratory patterns, human upper respiratory tract moves backward, the maximum displacement of the tertiary bronchus was 4.99 mm, the anterior wall was stretched, and the posterior wall was compressed. The wall shearing stress in the mouth-throat model was larger than that in the trachea-triple bifurcation, and the maximum shearing stress was 30.34 Pa. The maximum of airflow velocity reached maximum at 7.85 m/s in the glottis. The phenomenon of airflow separation appeared near the outer wall of the pharynx and the trachea, and the high velocity zone was created near the inner wall of the trachea. The airflow split at the divider and high velocity zone was generated near the inner wall of the trachea.
2012 Vol. 31 (1): 89-95 [Abstract] ( 295 ) HTML (1 KB)  PDF (1247 KB)  ( 732 )
96 Research on Capture Efficiency of Targeting Magnetic Drug Target Delivery Based on Non-Newton Fluid Multiphase Flow
ZHANG Yong Quan      WANG Shuai2WU Qiang2      WANG ShiGang1*LIU Li1
DOI: 10.3969/j.issn.0258-8021.2012.01.015
In order to analyze the influence of magnetic parameters on capture efficiency, a two phase CassonNewton model was developed to describe magnetic drug flowage in blood based on blood and rectangular magnet properties. The motion of magnetic nanoparticles under magnetic force and fluid force in blood vessel was analyzed, theoretic formulation of blood vessel 3D capture efficiency and further propose optimization model for capture drug volume was obtained to improve drug efficacy. Blood velocity and capture efficiency of Casson-Newton model, Newton model and Casson model were simulated by Matlab and compared to reveal the variation of capture drug volume, and the effects of particle radius, magnetic material radius ratio, magnetic field strength, distance between magnet and blood vessel, vessel radius, and other parameters on capture efficiency. According to the analysis results, the Non-Newton multiphase model performed system property better, the capture efficiency of Casson-Newton model was 4% higher than the two other models, and the capture drug volume reached maximum when magnetic materials radius ratio was 0.75 .
2012 Vol. 31 (1): 96-102 [Abstract] ( 263 ) HTML (1 KB)  PDF (990 KB)  ( 731 )
103 Simulation Study on  Influence of Orientation Parameter of Total Hip Components on the Range of Motion of Hip at Different Head/Neck Ratios Using Computer-Assisted Model
LI Yong Jiang1    CAI Chun Yuan1 LIN Rui Xin1 ZHANG Li Cheng1* YANG Guo Jing1 ZHOU De Biao1 WU Li Jun2
DOI: 10.3969/j.issn.0258-8021.2012.01.016
In this study a simulation model was proposed to examine the influence of orientation parameter of total hip components on the range of hip motion and obtain optimum combination of cup and neck anteversions in total hip arthroplasty at different general head/neck ratios (GR). A threedimensional generic parametric and kinematic simulation module of total hip arthroplasty （THA） was developed. The corresponding operative anteversion (OA) of the cup was related to the operative inclination (OI) of the cup which every 5° was calculated, and described using dots and lines in a coordinate system in which OI of acetabular cup was horizontal ordinate and OA of acetabular cup was vertical ordinate. The results showed that when CCDangle was 135°, the optimum relationship between OA of acetabular (Y) and FA of normal criteria and severe criteria (X）could be estimated by the formula: Y1=0.728X1+40.916（R2=0.999 9）and Y2=-0.738 4X2+46.456(R2=0.999 9）respectively, and the minimum allowable operative inclination (OImin) of acetabular should be more than 254.27GR-3.172（R2 = 0.991 7）and 230.58GR-2.519(R2 = 0.993 5）respectively. Large GR greatly increased the range of motion of the hip and the size of cup safe-zone. The more severe of the hip motion, the smaller size of the cup safezone, but could be retrieve by increasing the GR. The minimum allowable operative inclination (OImin) of acetabular was largely reduced with an increasing GR. The OA was negative with the femoral anteversion (FA).
2012 Vol. 31 (1): 103-109 [Abstract] ( 296 ) HTML (1 KB)  PDF (976 KB)  ( 431 )
110 Research on Hybrid Recognition Algorithms of Lung Cancer Breath Diagnosis Based on MOS and SAW Sensors
WANG Yi Shan1  WANG Di1  YU Kai1  WANG Lin1   ZHAO Cong1 ZHOU YinChang1    WANG Ping1*
DOI: 10.3969/j.issn.0258-8021.2012.01.017
The method of breath detection for lung cancer has gained growing interests in recent years. It is simple, fast, non-invasive, no need of marks and noncontact. Based on the lung cancer biomarkers obtained from the volatile organic compounds in breath samples of lung cancer patients and controls, we analyzed 27 breath samples of lung cancer patients and 27 breath samples of controls using MOS-SAW sensor coupling electronic nose technique. After preprocessing and analysis of the data, multiple methods, including PCA, LDA, PLS and ANN, were employed to establish the diagnosis models. And the discrimination results of these models were compared. It was showed that the ANN method had the best performance with the sensitivity of 92.59% and the specificity of 88.89%. So this method can be considered as a candidate one for the diagnosis of lung cancer through breath detection.
2012 Vol. 31 (1): 110-116 [Abstract] ( 394 ) HTML (1 KB)  PDF (1030 KB)  ( 610 )
117 Numerical Simulation of Porous Media on Evaporation for an Anaesthesia Vaporizer
XU Xiu Lin1*ZOU Ren Ling1   HU Xiu Fang1    YANG Shuai2
DOI: 10.3969/j.issn.0258-8021.2012.01.018
In order to improve the accuracy of anesthesia drug control and provide a theoretical basis for optimizing the structure of evaporator, the influence of physical characteristics of the porous medium evaporator core on the evaporation was investigated. Actual anesthetic evaporators were measured and a three-dimensional structure model was established with the Pro/E software. The effect of porous media on evaporation process in anesthesia vaporizer was simulated with CFD. Using FLUENT software, we analyzed the influence of physical properties of porous media on the performance of the evaporator and mixing process of the vaporized drugs with air. According to stochastic particle tracking in turbulent flow, the moving track of droplet of anesthesia drug in porous media space was traced. Then, the internal gas flow variation, the concentration distribution of drug volatilization process and mixing process with gas were obtained. Numerical simulation results showed that the porous media permeability, flow resistance during anesthesia drug volatilization and mixing process between anesthesia drug vapor and diluted gas all had influence on the accuracy and stability of the volatilization concentration for anesthesia drugs. The existence of porous medium reduced the flow rate of dilution gas. The increase of the porosity of porous media could promote drug evaporation and uniformity of the mixed gases. Due to the absorption of heat in the porous medium area, the maximum evaporation of drug was needed to determine the range of temperature compensation, ensuring the output stability and accuracy of the anesthetic drug concentration in the evaporator.
2012 Vol. 31 (1): 117-122 [Abstract] ( 259 ) HTML (1 KB)  PDF (747 KB)  ( 641 )
123 Cutting Simulation Model for Soft Tissue Surgery Based on Meshless Method
XU Shao Ping1*LI Chun Quan1,2JIANG Shun Liang1  LUO Jie3
DOI: 10.3969/j.issn.0258-8021.2012.01.019
It is very important to build a soft tissue cutting model for virtual surgery simulation system. Meshbased soft tissue cutting models take tissue cutting process as a mesh division between surgical tools and geometry mesh of soft tissue. As the soft tissue cutting process involves complex biomechanical problems, it is not easy to realize real-time interaction, which seriously affects virtual surgery simulation. In contrast, meshless soft tissue cutting models, breaking the limitations of meshbased model, have a great advantage in tactile/visual fidelity and realtime interaction. In this paper, we provide an overview of meshless soft tissue cutting models from the rendering quality and speed of force and visual feedback. Challenges in current studies are also discussed and summarized, and concerns that require further investigations are also included.
2012 Vol. 31 (1): 123-128 [Abstract] ( 401 ) HTML (1 KB)  PDF (377 KB)  ( 1123 )
129 Progress in Electrospun 3D Macroporous Nanofibrous Scaffolds for Tissue Engineering
ZHAO Shi Fang    YUAN Hui Hua     ZHANG Yan Zhong*
DOI: 10.3969/j.issn.0258-8021.2012.01.020
Electrospinning technique has received increasing attention in tissue engineering and regenerative medicine community due to its capability of making biomimetic nanofibrous scaffolds for engineering a variety of tissues. However, one of the major problems with electrospun nanofibrous scaffolds is that the densely arranged nanofibers and small pores (or interstices) in the scaffolds would inhibit proper infiltration of the cells and consequently limit tissue regeneration in vivo. To address this challenge, in recent years many concepts or strategies applicable at the electrospinning procedures have been devised to enlarge pore size of the electrospun scaffolds. This article addressed importance of porosity, pore size, and pore interconnectivity pertaining to tissue engineering scaffolds, and provided a detailed review on various approaches available for preparing 3 D macroporous nanofibrous scaffolds from electrospinning. Efficiencies, challenges, and prospects in the application of such electrospun nanofibrous scaffolds for tissue engineering were also briefly discussed.
2012 Vol. 31 (1): 129-140 [Abstract] ( 391 ) HTML (1 KB)  PDF (4136 KB)  ( 879 )
141 Electromagnetical Safety and Limited Standard of Magnetic Resonance Imaging
JI Qian Qian1    BAO JiaLi1*LI YuBo2     ZHU Chao Yang1
DOI: 10.3969/j.issn.0258-8021.2012.01.021
Magnetic Resonance Imaging (MRI), comprising of static magnetic fields, radio-frequency (RF) fields and timevarying gradient magnetic fields, is a diagnostic technique that a physical-effect is being transformed an image information for human after the immigrated electromagnetic energy imports ones. The electro magnetic fields may possibly have some risks for human health, such as nerve stimulation of gradient fields and thermal-effects of RF fields. During recently decades, FDA of USA has given a safety alert of MRI related death of patients with aneurysm clip, a public health notification of MRIcaused injuries in patients with implanted neurological stimulators and an advisory of risk of burns during MRI scans from transdermal drug patches with metallic backings. Nevertheless, MRI can be safe under a limited intensity electromagnetic fields. This review  reports the bio-effects and health risk associated with three fields and some national and international standards about the limited electromagnetic fields in MRI.
2012 Vol. 31 (1): 141-146 [Abstract] ( 377 ) HTML (1 KB)  PDF (315 KB)  ( 1349 )
147 The Construction and Analysis of the Optical System for Non-Invasive Blood Glucose Detection Based on Near Infrared Transmission Method
YANG Xing      JI Zhong*      YANG Li     PENG ChengLin
DOI: 10.3969/j.issn.0258-8021.2012.01.022
2012 Vol. 31 (1): 147-150 [Abstract] ( 245 ) HTML (1 KB)  PDF (441 KB)  ( 870 )
151 Research on  Temperature Control System for a Real-Time PCR Instrument
ZHANG Xin Lei   FENG Ji Hong*   KONG Jing Jing  YUAN Yu  Qiang
DOI: 10.3969/j.issn.0258-8021.2012.01.023
2012 Vol. 31 (1): 151-155 [Abstract] ( 335 ) HTML (1 KB)  PDF (790 KB)  ( 793 )
156 Effects of Cryoprotectants and Cooling Rates on Youngs Modulus of Porcine Articular Cartilage
LV Ya   XU Yi*   SUN Hui Jun   WANG Li Ping
DOI: 10.3969/j.issn.0258-8021.2012.01.024
2012 Vol. 31 (1): 156-160 [Abstract] ( 280 ) HTML (1 KB)  PDF (507 KB)  ( 578 )
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