Bio-Medical Materials and Engineering - Volume 24, issue 1

Authors: Yu, Chang Ho | Shin, Sun Hye | Jeong, Ho Choon | Go, Deung Young | Kwon, Tae Kyu

Article Type: Research Article

Abstract: The objectives were to assess the trunk and leg muscle activities during the trunk tilt exercise by a 3D dynamic exercise device capable of active and passive movements, to study the evaluation of Root Mean Squire (RMS), and to investigation the influence of the trunk positions on these muscle activities. Eighteen healthy volunteers were selected. None of the subjects had any history of lumber and trunk muscle problems. Rotation capability was enabled for the investigation of A (anterior), R (right), P (posterior), L (left), AR (anterior right), AL (anterior left), PR (posterior right), PL (posterior left) tilt directions. EMG signals …of trunk (rectus abdominis, external obliques, latissimus dorsi, erector spinae) muscles and leg (rectus femoris, Biceps femoris, Tibialis Anterior, gastrocnemius) muscles were taken out. Root Mean Squire (RMS) values were calculated. The results of this study indicate that different exercise patterns can be applied depending on the exercise types, which are appropriate and necessary to each user. We believe that the human body can be maintained in equilibrium through the interaction between the position and movement execution of the human body, contributing to the improvement of body balance control. Further quantitative data collection and analysis related to the development of various spinal stabilization exercise programs is required. In the near future, we will conduct a study concerning the effects of trunk tilt exercise in active and passive modes on the strength of the tilting muscles and postural balancing ability. Show more

Keywords: Trunk stabilization exercise, whole body tilt, active Tilt, passive tilt, EMG

DOI: 10.3233/BME-130805

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 245-254, 2014

Authors: Sun, Xin | Li, Ke | Ren, Hongwei | Li, Peng | Wang, Xinpei | Liu, Changchun

Article Type: Research Article

Abstract: The baPWV measurement is a non-invasive and convenient technique in an assessment of arterial stiffness. Despite its widespread application, the influence of different timing algorithms is still unclear. The present study was conducted to investigate the influence of six timing algorithms (MIN, MAX, D1, D2, MDP and INS) on the baPWV measurement and to evaluate the performance of them. Forty-five CAD patients and fifty-five healthy subjects were recruited in this study. A PVR acquisition apparatus was built up for baPWV measurement. The baPWV and other related parameters were calculated separately by the six timing algorithms. The influence and performance of …the six algorithms was analyzed. The six timing algorithms generate significantly different baPWV values (left: F=29.036, P<0.001; right: F=40.076, P<0.001). In terms of reproducibility, the MAX has significantly higher CV value (≥ 18.6%) than the other methods, while the INS has the lowest CV value (≤ 2.7%). On the performance of classification, the INS produces the highest AUC values (left: 0.854; right: 0.872). The MIN and D2 also have a passable performance (AUC > 0.8). The choice of timing algorithm affects baPWV values and the quality of measurement. The INS method is recommended for baPWV measurement. Show more

Keywords: Coronary artery disease, arterial stiffness, brachial-ankle pulse wave velocity, timing algorithm

DOI: 10.3233/BME-130806

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 255-261, 2014

Authors: Liu, Yong-jie | Cui, Shi-ming | He, Chao | Li, Jiu-kai | Wang, Qing-yuan

Article Type: Research Article

Abstract: Ti-6Al-4V implants that function as artificial joints are usually subjected to long-term cyclic loading. To study long-term fatigue behaviors of implant Ti-6Al-4V in vitro and in vivo conditions exceeding 107 cycles, constant stress amplitude fatigue experiments were carried out at ultrasonic frequency (20 kHz) with two different surface conditions (ground and polished) in ambient air and in a simulated body fluid. The initiation mechanisms of fatigue cracks were investigated with scanning electron microscopy. Improvement of fatigue strength is pronounced for polished specimens below 106 cycles in ambient air since fatigue cracks are initiated from surfaces of specimens. While …the cycles exceed 106 , surface conditions have no effect on fatigue behaviors because the defects located within the specimens become favorable sites for crack initiation. The endurance limit at 108 cycles of polished Ti-6Al-4V specimens decreases by 7% if it is cycled in simulated body fluid instead of ambient air. Fracture surfaces show that fatigue failure is initiated from surfaces in simulated body fluid. Surface improvement has a beneficial effect on fatigue behaviors of Ti-6Al-4V at high stress amplitudes. The fatigue properties of Ti-6Al-4V deteriorate and the mean endurance limits decrease significantly in simulated body fluid. Show more

Keywords: Ti-6Al-4V, high cycle fatigue, surface condition, simulated body fluid, S-N curve

DOI: 10.3233/BME-130807

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 263-269, 2014

Authors: Liu, Chengyu | Zheng, Dingchang | Zhao, Lina | Liu, Changchun

Article Type: Research Article

Abstract: It has been reported that Gaussian functions could accurately and reliably model both carotid and radial artery pressure waveforms (CAPW and RAPW). However, the physiological relevance of the characteristic features from the modeled Gaussian functions has been little investigated. This study thus aimed to determine characteristic features from the Gaussian functions and to make comparisons of them between normal subjects and heart failure patients. Fifty-six normal subjects and 51 patients with heart failure were studied with the CAPW and RAPW signals recorded simultaneously. The two signals were normalized first and then modeled by three positive Gaussian functions, with their peak …amplitude, peak time, and half-width determined. Comparisons of these features were finally made between the two groups. Results indicated that the peak amplitude of the first Gaussian curve was significantly decreased in heart failure patients compared with normal subjects (P<0.001). Significantly increased peak amplitude of the second Gaussian curves (P<0.001) and significantly shortened peak times of the second and third Gaussian curves (both P<0.001) were also presented in heart failure patients. These results were true for both CAPW and RAPW signals, indicating the clinical significance of the Gaussian modeling, which should provide essential tools for further understanding the underlying physiological mechanisms of the artery pressure waveform. Show more

Keywords: Artery pressure waveform analysis, waveform matching, Gaussian function, heart failure

DOI: 10.3233/BME-130808

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 271-277, 2014

Authors: Liang, Ding | Ivanov, Kamen | Li, Huiqi | Ning, Yunkun | Zhang, Qi | Wang, Lei | Zhao, Guoru

Article Type: Research Article

Abstract: Research on falls in elderly people has a great social significance because of the rapidly growing of the aging population. The pre-impact lead time of fall (PLT) is an important part of the human fall theory. PLT is the longest time for a person who is going to fall to take action in order to prevent the fall or to reduce bodily injuries from the fall impact. However, there is no clear definition of PLT so far. There is also no comparative study for active and passive falls. In this study, we proposed a theoretical definition of the PLT, based …on a new method of fall event division. We also compared the differences of PLT and the related angles between active and passive falls. Eight healthy adult subjects were arranged to perform three kinds of activities of daily living (sitting, walking and lying), and two kinds fall activities (active and passive) in three directions (forward, backward and lateral fall). Nine inertial sensor modules were used to measure the body segmental kinematic characteristics of each subject in our experimental activities. In this paper, a fall event was suggested to divide into three or four phases and then the critical phase could be divided into three periods (pre-impact, impact, and post-impact). Two fall models were developed for active and passive falls using acceleration data. The average value of PLT for active falls is about 514 ± 112 ms and it is smaller than the value for passive falls, which is 731 ± 104 ms. The longest PLTs were measured on the chest or waist instead of other locations, such as the thigh and shank. The PLTs of the three kinds of fall activities were slightly different, but there was a significant difference between two fall modes. The PLT showed the correlation to the body angle at the start of PLT, but it was uncorrelated at the end of PLT. The angles at the start of PLT had slight variations (<10 degrees) from the steady standing state except in passive forward falls (max 16 degrees) due to the self-control. The landing angles were significantly different in the both fall modes in all the three directions of fall, indicating the state of the trunk was uncertain when the hip contacted the ground. It can be concluded that it is feasible to prevent falls by using an early pre-impact fall alarm device; the present study provides important reference for development of pre-impact fall alarm devices. Show more

Keywords: fall prevention, pre-impact fall detection, pre-impact lead time (PLT), inertial sensors

DOI: 10.3233/BME-130809

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 279-288, 2014

Authors: Wong, Derek F. | Chao, Lidia S. | Zeng, Xiao Dong

Article Type: Research Article

Abstract: Discretization of a continuous-valued symptom (attribute) in medical data set is a crucial preprocessing step for the medical classification task. This paper proposes a supportive attribute – assisted discretization (SAAD) model for medical diagnostic problems. The intent of this approach is to discover the best supportive symptom that correlates closely with the continuous-valued symptom being discretized and to conduct the discretization process using the significant supportive information that is provided by the best supportive symptom, because we hypothesize that a good discretization scheme should rely heavily on the interaction between a continuous-valued attribute and both its supportive attribute and the …class attribute. SAAD can consider each continuous-valued symptom differently and intelligently, which allows it to be capable of minimizing the information lost and the data uncertainty. Hence, SAAD results in higher classification accuracy. Empirical experiments using ten real-life datasets from the UCI repository were conducted to compare the classification accuracy achieved by several prestigious classifiers with SAAD and other state-of-the-art discretization approaches. The experimental results demonstrate the effectiveness and usefulness of the proposed approach in enhancing the diagnostic accuracy. Show more

Keywords: Discretization, data preprocessing, supportive attribute interdependence, bioinformatics, medical classification

DOI: 10.3233/BME-130810

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 289-295, 2014

Authors: Yu, Chang Ho | Piao, Young Jun | Kim, Kyung | Kwon, Tae Kyu

Article Type: Research Article

Abstract: A new training system that can adjust training intensity and indicate the center pressure of a subject was proposed by applying controlled electric current to the Magneto-Rheological damper. The experimental studying on the muscular activities were performed in lower extremities during maintaining and moving exercises, which were processed on an unstable platform with Magneto rheological dampers and recorded in a monitor. The electromyography (EMG) signals of the eight muscles in lower extremities were recorded and analyzed in certain time and frequency domain. Muscles researched in this paper were rectus femoris (RF), biceps femoris (BF), tensor fasciae latae (TFL), vastuslateralis (VL), …vastusmedialis (VM), gastrocnemius (Ga), tibialis anterior (TA), and soleus (So). Differences of muscular activities during four moving exercises were studied in our experimental results. The rate of the increment of the muscular activities was affected by the condition of the unstable platform with MR dampers, which suggested the difference of moving exercises could selectively train each muscle with varying intensities. Furthermore, these findings also proposed that this training system can improve the ability of postural balance. Show more

Keywords: Muscular activities, magneto-rheological damper, unstable platform

DOI: 10.3233/BME-130811

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 297-306, 2014

Authors: Zhou, Xiaoming | Zhang, Congyao | Liu, Dong C.

Article Type: Research Article

Abstract: Color flow imaging has been well applied in clinical diagnosis. For the high quality color flow images, clutter filter is important to separate the Doppler signals from blood and tissue. Traditional clutter filters, such as finite impulse response, infinite impulse response and regression filters, were applied, which are based on the hypothesis that the clutter signal is stationary or tissue moves slowly. However, in realistic clinic color flow imaging, the signals are non-stationary signals because of accelerated moving tissue. For most related papers, simulated RF signals are widely used without in vivo I/Q signal. Hence, in this paper, adaptive polynomial …regression filter, which is down mixing with instantaneous clutter frequency, was proposed based on in vivo carotid I/Q signal in realistic color flow imaging. To get the best performance, the optimal polynomial order of polynomial regression filter and the optimal polynomial order for estimation of instantaneous clutter frequency respectively were confirmed. Finally, compared with the mean blood velocity and quality of 2-D color flow image, the experiment results show that adaptive polynomial regression filter, which is down mixing with instantaneous clutter frequency, can significantly enhance the mean blood velocity and get high quality 2-D color flow image. Show more

Keywords: Color flow imaging, clutter filter, polynomial regression filter, mean clutter frequency, instantaneous clutter frequency

DOI: 10.3233/BME-130812

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 307-313, 2014

Authors: Guo, Xuemei | Zhai, Fei | Nan, Qun

Article Type: Research Article

Abstract: Renal sympathetic denervation (RSD) by the radiofrequency ablation was used to treat the resistant hypertension in clinic and has achieved curative effect. But the temperature distribution in the artery walls and the blood flow have not been investigated. Finite element method (FEM) based on Comsol Multiphysics 4.3a software was used to simulate the temperature distribution in the renal artery. The results of renal artery temperature distribution as well as blood flow effect on the temperature field were obtained, which demonstrated that the blood velocity is very crucial in the temperature distribution of blood vessel near antenna. When the speed of …blood is 0.4 m/s, the highest temperature rise of arterial wall near the antenna is 8.882°C (37°C to 45.882°C) and contralateral artery wall's highest temperature rise is about 5°C (37°C to 42°C). This temperature value can damage renal sympathetic nerves to cure the resistant hypertension. Due to the blood flow, the temperature field stretches to the direction of blood flow. The temperature rise of blood is only in a small range (37°C to 41°C) at both ends of the antenna. The simulation of RSD by the radiofrequency ablation can give doctors a better scheme to avoid the vascular injury in different blood flow rates and radiofrequency voltages. Show more

Keywords: Renal sympathetic denervation, resistant hypertension, finite element method, temperature distribution, radiofrequency ablation

DOI: 10.3233/BME-130813

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 315-321, 2014

Authors: Bernad, Elena S. | Bernad, Sandor I. | Craina, Marius L.

Article Type: Research Article

Abstract: In this study, effects of serial stenosis on coronary hemodynamics were investigated in the human right coronary artery (RCA) using blood flow analysis. A 3-D model of a serial stenosed RCA was reconstructed based on multislice computerized tomography images. Numerical analysis examined the effect of multiple serial stenoses on the hemodynamic characteristics such as flow separation, pressure drop and FFR. Pressure loss associated with flow expansion after each constriction was large. Overall pressure drop increased from 1700 Pa (12.75 mmHg) at the end diastole to 11000 Pa (82.5 mmHg) at the peak systole. In two stenoses the corresponding pressure gradients …werearound 30 mmHg and corresponded to the stenosis with FFR < 0.7 (associated to the sever stenosis). Severe stenosies caused large pressure drops across the throat. Blood flow distal to the stenosis was associated with fluctuations of the wall shear stress and vorticity. Show more

Keywords: serial stenosis, right coronary artery, hemodynamics, fractional flow reserve, pressure drop

DOI: 10.3233/BME-130814

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 323-334, 2014

Authors: Lai, Jun | Wei, Qingjie

Article Type: Research Article

Abstract: Segmenting lung fields from CT (Computed Tomography) scans is an important task for the analysis, diagnosis and treatment of pulmonary diseases. Although many segmentation methods have been presented, some new automatic segmentation methods for the lung fields are still proposed for the CT scans. This paper proposes a novel segmentation method for lung fields by using morphological closing operations and thresholding for normal lungs in CT scans. Additionally, under the guidance of anatomic information, the lung fields could be well segmented with lobar fissure, thin junction between the left/right lung fields, indentation of the blood vessels and bronchi-walls. This experiment …is performed by employing the thoracic CT scans datasets, and it is proved to be an effective method. Show more

Keywords: Segmentation, morphological operation, junction region, lung fields, lobar fissure

DOI: 10.3233/BME-130815

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 335-340, 2014

Authors: Choi, Ahnryul | Rim, Yonghoon | Mun, Jeffrey S. | Kim, Hyunggun

Article Type: Research Article

Abstract: Alterations of normal mitral valve (MV) function lead to mitral insufficiency, i.e., mitral regurgitation (MR). Mitral repair is the most popular and most efficient surgical intervention for MR treatment. An annuloplasty ring is implanted following complex reconstructive MV repairs to prevent potential reoccurrence of MR. We have developed a novel finite element (FE)-based simulation protocol to perform patient-specific virtual ring annuloplasty following the standard clinical guideline procedure. A virtual MV was created using 3D echocardiographic data in a patient with mitral annular dilation. Proper type and size of the ring were determined in consideration of the MV apparatus geometry. The …ring was positioned over the patient MV model and annuloplasty was simulated. Dynamic simulation of MV function across the complete cardiac cycle was performed. Virtual patient-specific annuloplasty simulation well demonstrated morphologic information of the MV apparatus before and after ring implantation. Dynamic simulation of MV function following ring annuloplasty demonstrated markedly reduced stress distribution across the MV leaflets and annulus as well as restored leaflet coaptation compared to pre-annuloplasty. This novel FE-based patient-specific MV repair simulation technique provides quantitative information of functional improvement following ring annuloplasty. Virtual MV repair strategy may effectively evaluate and predict interventional treatment for MV pathology. Show more

Keywords: Mitral valve, annuloplasty, mitral repair, patient-specific, finite element

DOI: 10.3233/BME-130816

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 341-347, 2014

Authors: Ke, Yufeng | Chen, Long | Fu, Lan | Jia, Yihong | Li, Penghai | Zhao, Xin | Qi, Hongzhi | Zhou, Peng | Zhang, Lixin | Wan, Baikun | Ming, Dong

Article Type: Research Article

Abstract: Varieties of neurophysiological measures have been utilized in visual attention studies. The linear parameters like power spectrum are the most commonly used features in the existing studies. In this paper, however, nonlinear parameters including approximate entropy, sample entropy and multiscale entropy were tested. All subjects were instructed to perform tasks with three different attention levels (i.e. attention, no attention and rest) in two experiments. Nonlinear features were extracted from the EEG signals. Then, statistical analyses and classification with support vector machine (SVM) were performed. A comparison between the classification results based on the linear feature / and the sample entropy …was performed for further analysis. The results suggest that sample entropy stands out in the dynamical parameters with the accuracies of 76.19% and 85.24% in recognition of three levels of attention for the two experiments respectively. And the further comparison shows that the sample entropy performs even better than the / power ratio. It is suggested that nonlinear dynamical parameters may be indispensable for a robust attention recognition system. Show more

Keywords: Visual attention, EEG, approximate entropy, sample entropy, multiscale entropy, support vector machine

DOI: 10.3233/BME-130817

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 349-355, 2014

Authors: Xiong, Yijun | Luo, Yu | Huang, Wentao | Zhang, Wenjia | Yang, Yong | Gao, Junfeng

Article Type: Research Article

Abstract: The classification of EEG tasks has drawn much attention in recent years. In this paper, a novel classification model based on independent component analysis (ICA) and Extreme learning machine (ELM) is proposed to detect lying. Firstly, ICA and its topography information were used to automatically identify the P300 ICs. Then, time and frequency-domain features were extracted from the reconstructed P3 waveforms. Finally, two classes of feature samples were used to train ELM, Back-propagation network (BPNN) and support vector machine (SVM) classifiers for comparison. The optimal number of P3 ICs and the values of classifier parameter were optimized by the cross-validation …procedures. Experimental results show that the presented method (ICA_ELM) achieves the highest training accuracy of 95.40% with extremely less training and testing time on detecting P3 components for the guilty and the innocent subjects. The results indicate that the proposed method can be applied in lie detection. Show more

Keywords: Independent component analysis, extreme learning machine, classification, EEG, ERP

DOI: 10.3233/BME-130818

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 357-363, 2014

Authors: Xin, Yi | Chen, Yu | Hao, Wei Tuo

Article Type: Research Article

Abstract: A novel approach of ECG baseline wander correction based on mean-median filter and empirical mode decomposition is presented in this paper. The low frequency parts of the original signals were removed by the mean median filter in a nonlinear way to obtain the baseline wander estimation, then its series of IMFs were sifted by t-test after empirical mode decomposition. The proposed method, tested by the ECG signals in MIT-BIH Arrhythmia database and European ST_T database, is more effective compared with other baseline wander removal methods.

Keywords: ECG, Baseline Wander, Mean-median Filter, Empirical Mode Decomposition

DOI: 10.3233/BME-130820

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 365-371, 2014

Authors: Zhou, Lu | Zhou, Linghong | Zhang, Shuxu | Zhen, Xin | Yu, Hui | Zhang, Guoqian | Wang, Ruihao

Article Type: Research Article

Abstract: Deformable image registration (DIR) was widely used in radiation therapy, such as in automatic contour generation, dose accumulation, tumor growth or regression analysis. To achieve higher registration accuracy and faster convergence, an improved ‘diffeomorphic demons’ registration algorithm was proposed and validated. Based on Brox et al.'s gradient constancy assumption and Malis's efficient second-order minimization (ESM) algorithm, a grey value gradient similarity term and a transformation error term were added into the demons energy function, and a formula was derived to calculate the update of transformation field. The limited Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm was used to optimize the energy function so that …the iteration number could be determined automatically. The proposed algorithm was validated using mathematically deformed images and physically deformed phantom images. Compared with the original ‘diffeomorphic demons’ algorithm, the registration method proposed achieve a higher precision and a faster convergence speed. Due to the influence of different scanning conditions in fractionated radiation, the density range of the treatment image and the planning image may be different. In such a case, the improved demons algorithm can achieve faster and more accurate radiotherapy. Show more

Keywords: Demons algorithm, deformable registration, gradient constancy assumption, efficient second-order minimization, L-BFGS algorithm

DOI: 10.3233/BME-130821

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 373-382, 2014

Authors: Tang, Dai | Kim, Daejoong

Article Type: Research Article

Abstract: The ion selective transport plays an important role in the function of cell membranes, and promotes the application of artificial permeable membranes. This phenomenon has been studied in case for different diameters and functional groups of nanopores. In this work, we focus on the effect of anions on cation selectivity, in particular the influence of various halide ions on K+ and Na+ selectivity. We adopted molecular dynamics simulations with non-charged nanopores under constant temperature and uniform concentration. The results show K+-selectivity in the solution with Cl- and Na+-selectivity in the solution with Br- and I-. This selectivity, on the contrary, …disappears in the solution with F-. We also investigate the change of the hydration shell of ions and cation-anion interactions between in the bulk region and in the nanopores, which could explain this selective phenomenon. Show more

Keywords: ion selectivity, halide ions, potassium and sodium, hydration shell of ion

DOI: 10.3233/BME-130822

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 383-390, 2014

Authors: Tanantong, Tanatorn | Nantajeewarawat, Ekawit | Thiemjarus, Surapa

Article Type: Research Article

Abstract: Five well-known arrhythmia classification algorithms were compared in this paper based on the recommendations in AAMI standard. They are C4.5, k-Nearest Neighbor, Multilayer Perceptron, PART, and Support Vector Machine, respectively, with inputs related to heartbeat intervals and ECG morphological features. They were evaluated on three independent datasets, including the MIT-BIH arrhythmia database, a collection of ECG signals acquired from healthy subjects by the wireless Body Sensor Network (BSN) nodes, and a third dataset captured also by the BSN nodes. Results showed the overall accuracy on the MIT-BIH arrhythmia database was approximately 99.04%, with high sensitivity, specificity, and selectivity. When tested …with ECG signals acquired from the human subjects, which were partially deteriorated due to several factors, e.g., motion artifacts and data transmission problems, the overall accuracy of 94.19% and that of 81.22% were obtained for static activities and dynamic activities, respectively. In addition, the effects of the signal quality from these human subjects on false alarms were investigated. When false alarms occurring in signal segments with low quality were excluded, the number of false detections reduced from 14.17% to 8.65%. When evaluated on signals generated by the patient simulator, which included several types of premature ventricular contraction without artifacts from body movements, a high classification accuracy was also observed. Show more

Keywords: Arrhythmia classification, body sensor network, ambulatory monitoring, wireless ECG, signal quality

DOI: 10.3233/BME-130823

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 391-404, 2014

Authors: Shin, Dong Ho | Kim, Dong Wook | Lim, Hyung Gyu | Jung, Eui Sung | Seong, Ki Woong | Lee, Jyung Hyun | Kim, Myoung Nam | Cho, Jin Ho

Article Type: Research Article

Abstract: Round window placement of a 3-coil transducer offers a new approach for coupling an implantable hearing aid to the inner ear. The transducer exhibits high performance at low-frequencies. One remarkable feature of the 3-coil transducer is that it minimizes leakage flux. Thus, the transducer, which consists of two permanent magnets and three coils, can enhance vibrational displacement. In human temporal bones, stapes vibration was observed by laser Doppler vibrometer in response to round window stimulation using the 3-coil transducer. Coupling between the 3-coil transducer and the round window was connected by a wire-rod. The stimulation created stapes velocity when the …round window stimulated. Performance evaluation was conducted by measuring stapes velocity. To verify the performance of the 3-coil transducer, stapes velocity for round window and tympanic membrane stimulation were compared, respectively. Stapes velocity by round window stimulation using the 3-coil transducer was approximately 14 dB higher than that achieved by tympanic membrane stimulation. The study shows that 3-coil transducer is suitable for implantable hearing aids. Show more

Keywords: Round window, temporal bone, stapes velocity, 3-coil transducer

DOI: 10.3233/BME-130825

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 405-411, 2014

Authors: Jang, Dong-Jin | Kim, Sung Tae | Lee, Kooyeon | Oh, Euichaul

Article Type: Research Article

Abstract: The intestinal absorption and antiasthmatic efficacy of poorly water-soluble curcumin (CUR), which has low solubility and permeability, was increased by fabricating solid dispersion granules (SDGs). The SDG containing CUR (SDG-CUR) was prepared by dispersing CUR in excess Cremophor RH40 as a solubilizer and Ryoto sugar ester L-1695 as an absorption enhancer using fluid bed granulation. We evaluated the physicochemical properties such as crystallinity and dissolution, pharmacokinetics, and antiasthmatic efficacy of SDG-CUR. Our results showed that CUR was molecularly dispersed, and the dissolution of SDG-CUR was significantly higher than that of native CUR. In addition, the blood concentration of SDG-CUR in …rats was much higher than that of native CUR. Compared to CUR, SDG-CUR showed a 9.1- and 13.1-fold increase in area under the plasma concentration-time curve (AUC) and maximum plasma concentration (Cmax ), respectively. Further, SDG-CUR effectively alleviated airway hyperresponsiveness and levels of T-helper 2 cytokines (interleukin-4, interleukin-5, and interleukin-13) in a murine model of asthma. In conclusion, our results suggest that the SDGs could be considered as a potential oral formulation to enhance the absorption and efficacy of CUR. Show more

Keywords: curcumin, absorption enhancer, fluid bed granulation, solid dispersion granule, antiasthmatic efficacy

DOI: 10.3233/BME-130826

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 413-429, 2014

Authors: Fu, Jian | Tan, Renbo

Article Type: Research Article

Abstract: X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source …micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology. Show more

Keywords: X-ray in-line phase contrast imaging, micro computed tomography, reconstruction algorithm, X-ray tube source

DOI: 10.3233/BME-130827

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 431-437, 2014

Authors: Woo, SeongTak | Jung, EuiSung | Lim, HyungGyu | Lee, Jang Woo | Seong, Ki Woong | Won, Chul Ho | Kim, Myoung Nam | Cho, Jin Ho | Lee, Jyung Hyun

Article Type: Research Article

Abstract: Input for fully implantable hearing devices (FIHDs) is provided by an implantable microphone under the skin of the temporal bone. However, the implanted microphone can be affected when the FIHDs user chews. In this paper, a dual implantable microphone was designed that can filter out the noise from mastication. For the in vivo experiment, a fabricated microphone was implanted in a rabbit. Pure-tone sounds of 1 kHz through a standard speaker were applied to the rabbit, which was given food simultaneously. To evaluate noise reduction, the measured signals were processed using a MATLAB program based adaptive filter. To verify the …proposed method, the correlation coefficients and signal to-noise ratio before and after signal processing were calculated. By comparing the results, signal-to-noise ratio and correlation coefficients are enhanced by 6.07dB and 0.529 respectively. Show more

Keywords: Implantable microphone, in vivo experiment, adaptive filter, Mastication, fully implantable hearing devices

DOI: 10.3233/BME-130828

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 439-444, 2014

Authors: Wang, Zhigang | Tai, Lik-Ren | McLean, Donald | Wright, Emma J. | Florence, Gordon J. | Brown, Stuart I. | Andre, Pascal | Cuschieri, Alfred

Article Type: Research Article

Abstract: Safe and effective manipulation of soft tissue during laparoscopic procedures can be achieved by the use of mucoadhesive polymer films. A series of novel adhesive polymer films were formulated in house based on either Carbopol or Chitosan modified systems. The mechanical properties of the polymers and their adherence to bowel were evaluated using ex-vivo pig bowel immersed in 37°C water bath and connected to an Instron tensiometer. Young's modulus was 300 kPa for the Carbopol-polymer and 5 kPa for the Chitosan-polymer. The Chitosan-polymer exhibited much larger shear adhesion than its tensile adhesion: 3.4 N vs. 1.2. Both tensile and shear …adhesions contributed to the large retraction force (2.6 N) obtained during l polymer-bowel retraction testing. Work of adhesion at the polymer/serosa interface, defined as the area under the force curve, was 64 mJ, which is appreciably larger than that reported with existing polymers. In conclusion, adhesive polymers can stick to the serosal side of the bowel with an adhesive force, which is sufficient to lift the bowel, providing a lower retraction stress than that caused by laparoscopic grasping which induces high localized pressures on the tissue. Show more

Keywords: mucoadhesive polymer, mechanical property, adhesive force, laparoscopic surgery, bowel retraction

DOI: 10.3233/BME-130829

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 445-451, 2014

Authors: Yang, Hoe S. | Yoo, Ji W. | Lee, Bo A. | Choi, Chang K. | You, Joshua H.

Article Type: Research Article

Abstract: The present study established inter-tester and intra-tester reliabilities of ultrasound imaging and diagnostically differentiated muscle imbalances in lateral abdominal muscle sizes between normal adolescents and adolescents with idiopathic scoliosis (AIS). Fifteen adolescents with AIS were age- and gender-matched with 15 normal adolescents. There was no significant difference between bilateral abdominal muscles in normal adolescents, but there was a significant difference between bilateral abdominal muscles in adolescents with AIS (P<0.05). Overall, inter-tester and intra-tester reliabilities in normal and AIS adolescents ranged from 0.801–0.984. This novel study shows that using ultrasound imaging to measure lateral abdominal muscle thickness is: (1) highly reliable …between and within the testers; and (2) capable of distinguishing between subjects with and without pathological muscle morphology due to AIS. Show more

Keywords: Muscle thickness, Ultrasound imaging, Adolescent idiopathic scoliosis, Reliability

DOI: 10.3233/BME-130830

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 453-458, 2014

Authors: Wang, Lifang | Zhou, Xiaohua | Shen, Mingxiu | Sun, Yanping | Sun, Guifang

Article Type: Research Article

Abstract: Hemodynamics plays a crucial role in the formation, progression and rupture of intracranial aneurysms. Understanding these mechanisms is important to improve current diagnosis and treatment of intracranial aneurysms. In this study we simulate and analyze the pressure gradients and the blood flow fields in growing intracranial aneurysms. Firstly, the pressure gradients are obtained according to the blood velocity waveform at the axis of the inlet to the artery, which can be acquired by transcranial Doppler technology. Then, blood flow fields are calculated by solving the linearized Navier-Stokes equations and continuity equation using the Fourier series method. Results show that the …higher the aneurysm dilatation degree is, the lower the maximum oscillatory velocity will be. Therefore, the oscillatory velocity may be used to analyze the characteristics of blood flow signals from aneurysm and to forecast the size of aneurysm. This sensitive parameter can be utilized for the detection of vessel diseases, which is promising to provide a useful reference in clinical application. Show more

Keywords: hemodynamics, aneurysms, numerical simulation, oscillatory blood flow, pressure gradients

DOI: 10.3233/BME-130831

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 459-466, 2014

Authors: Lin, Haoming | Wang, Tianfu | Chen, Siping

Article Type: Research Article

Abstract: This paper describes a new method for shear wave velocity estimation that is capable of extruding outliers automatically without preset threshold. The proposed method is an adaptive random sample consensus (ARANDSAC) and the metric used here is finding the certain percentage of inliers according to the closest distance criterion. To evaluate the method, the simulation and phantom experiment results were compared using linear regression with all points (LRWAP) and radon sum transform (RS) method. The assessment reveals that the relative biases of mean estimation are 20.00%, 4.67% and 5.33% for LRWAP, ARANDSAC and RS respectively for simulation, 23.53%, 4.08% and …1.08% for phantom experiment. The results suggested that the proposed ARANDSAC algorithm is accurate in shear wave speed estimation. Show more

Keywords: Shear elasticity, shear wave speed, shear wave displacement, adaptive RANDSAC, radon sum

DOI: 10.3233/BME-130832

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 467-474, 2014

Authors: Wei, Qiang | Xu, Yuan-Qing | Tian, Fang-bao | Gao, Tian-xin | Tang, Xiao-ying | Zu, Wen-Hong

Article Type: Research Article

Abstract: A size-based blood cell sorting model with a micro-fence structure is proposed in the frame of immersed boundary and lattice Boltzmann method (IB-LBM). The fluid dynamics is obtained by solving the discrete lattice Boltzmann equation, and the cells motion and deformation are handled by the immersed boundary method. A micro-fence consists of two parallel slope post rows which are adopted to separate red blood cells (RBCs) from white blood cells (WBCs), in which the cells to be separated are transported one after another by the flow into the passageway between the two post rows. Effected by the cross flow, RBCs …are schemed to get through the pores of the nether post row since they are smaller and more deformable compared with WBCs. WBCs are required to move along the nether post row till they get out the micro-fence. Simulation results indicate that for a fix width of pores, the slope angle of the post row plays an important role in cell sorting. The cells mixture can not be separated properly in a small slope angle, while obvious blockages by WBCs will take place to disturb the continuous cell sorting in a big slope angle. As an optimal result, an adaptive slope angle is found to sort RBCs form WBCs correctly and continuously. Show more

Keywords: Blood cell separation, Lattice Boltzmann method, immersed Boundary, Microfludics, Cross flow

DOI: 10.3233/BME-130833

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 475-481, 2014

Authors: Zhu, Zhiwen | Zhang, Qingxin | Xu, Jia

Article Type: Research Article

Abstract: Nonlinear dynamic characteristics of shape memory alloy (SMA) intravascular stent under radial stochastic loads were studied in this paper. Von de Pol item was improved to interpret the hysteretic phenomena of SMA, and the nonlinear dynamic model of SMA intravascular stent under radial stochastic loads was developed. The conditions of stochastic stability of the system were obtained in singular boundary theory. The steady-state probability density function of the dynamic response of the system was given, and the stochastic Hopf bifurcation characteristics of the system were analyzed. Theoretical analysis and numerical simulation show that the stability of the trivial solution varies …with bifurcation parameters, and stochastic Hopf bifurcation appears in the process, which can cause stent fracture or loss. The results of this paper are helpful to application of SMA intravascular stent in biomedical engineering fields. Show more

Keywords: Shape memory alloy (SMA), intravascular stent, radial stochastic load, stochastic stability, stochastic bifurcation

DOI: 10.3233/BME-130834

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 483-489, 2014

Authors: Zhang, Chi | Wang, Ling | Li, Xiaoyun | Li, Shuyu | Pu, Fang | Fan, Yubo | Li, Deyu

Article Type: Research Article

Abstract: Circle of Willis (CoW) plays a significant role in maintaining the blood supply for the brain. Specifically, when the stenosis occurs in the internal carotid artery (ICA), abnormal structures of CoW would decrease the compensatory capacity, leading to the local insufficiency of cerebral blood supply. The present paper built a series of lumped parameter models for CoW, and simulated the blood redistribution caused by the unilateral ICA stenosis with different severities in cerebral arteries in the normal and abnormal CoW respectively. The results showed that when unilateral ICA stenosis occurred, the collateral circulation was built through the anterior communicating artery …and the ipsilateral posterior communicating artery, maintaining the flow in cerebral arteries. The absence of the two communicating arteries would cause an obvious decrease of flow in local cerebral arteries in the anterior circulation. In conclusion, the two arteries play a significant role in maintaining the balance of cerebral blood supply in the development of ICA stenosis. Show more

Keywords: Circle of Willis, internal carotid artery, stenosis, anatomical variation, lumped parameter model

DOI: 10.3233/BME-130835

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 491-499, 2014

Authors: Wang, Tianmiao | Li, Changsheng | Hu, Lei | Tang, Peifu | Zhang, Lihai | Du, Hailong | Luan, Sheng | Wang, Lifeng | Tan, Yiming | Peng, Cheng

Article Type: Research Article

Abstract: In traditional long bone fracture reduction surgery, there are some drawbacks such as low accuracy, high radiation for surgeons and a risk of infection. To overcome these disadvantages, a removable hybrid robot system is developed, which integrates a removable series-parallel mechanism with a motor-double cylinder (MDC) driven mode. This paper describes the mechanism in detail, analyses the principle and the method of the fracture reduction, presents the surgical procedure, and verifies the reduction accuracy by experiments with bone models. The results are shown as follows. The mean deviations of the axial displacement and lateral displacement are 1.60mm and 1.26mm respectively. …The standard deviations are 0.69mm and 0.30mm. The mean deviations of the side angle and turn inward are 2.06° and 2.22° respectively. The standard deviations are 0.50° and 0.99°. This minimally invasive robot features high accuracy and zero radiation for surgeons, and is able to conduct fracture reduction for long bones. Show more

Keywords: Hybrid robot, fracture reduction, long bone, surgical robot

DOI: 10.3233/BME-130836

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 501-509, 2014

Authors: Luan, Sheng | Sun, Lei | Hu, Lei | Hao, Aimin | Li, Changsheng | Tang, Peifu | Zhang, Lihai | Du, Hailong

Article Type: Research Article

Abstract: This paper presents a compact orthopedic robot designed with modular concept. The layout of the modular configuration is adaptive to various conditions such as surgical workspace and targeting path. A biplanar algorithm is adopted for the mapping from the fluoroscopic image to the robot, while the former affine based method is satisfactory only when the projection rays are basically perpendicular to the reference coordinate planes. This paper introduces the area cross-ratio as a projective invariant to improve the registration accuracy for non-orthogonal orientations, so that the robotic system could be applied to more orthopedic procedures under various C-Arm orientation conditions. …The system configurations for femoral neck screw and sacroiliac screw fixation are presented. The accuracy of the robotic system and its efficacy for the two typical applications are validated by experiments. Show more

Keywords: Medical robotics, projective invariant, modular design

DOI: 10.3233/BME-130837

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 511-518, 2014

Authors: Liu, Hongying | Qiao, Panpan | Wu, Xueli | Wang, Li | Ao, Yilu | Jia, Ziru | Pi, Xitian

Article Type: Research Article

Abstract: Prior research indicated that occult blood screening can be used to detect early gastric cancer. Based on capsule endoscopy and occult blood detection theory, an automatic detection capsule system for gastric occult blood (GOB) was proposed. This paper designed the detecting sensor, image acquisition system and wireless transmitter module respectively based on collaurum immune theory, the image sensor and radio frequency chip. In vitro experiments were conducted to testify the system, and the detecting result image information was acquired by the image acquisition (IMAQ) system and transmitted to the outside of the body through the wireless transmitter module. The receiver …module received and displayed the information on the computer, from which doctors could diagnose whether there was occult blood (OB) or not. Therefore, this paper provides a new idea for the screening of early-stage gastric cancer with reliability and simplicity. Show more

Keywords: smart capsule system, gastric occult blood, imaging sensor, image acquisition, wireless transmission

DOI: 10.3233/BME-130838

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 519-528, 2014

Authors: Deng, Xin | Xu, Jian-Xin

Article Type: Research Article

Abstract: This paper provides an undulatory locomotion model inspired by C. elegans, whose nervous system and muscular structure are well studied. C. elegans is divided into 11 muscle segments according to its anatomical structure, and represented as a multi-joint rigid link model in this work. In each muscle segment, there are four pieces of muscles located in four quadrants. The muscles change their lengths according to the outputs of nervous system. In this work, the dynamic neural networks (DNN) are adopted to represent the nervous system. The DNN are divided into the head DNN and the body DNN. The head DNN …produces the sinusoid waves to generate the forward and backward undulatory movements. The body DNN with 11 segments is responsible for passing the sinusoid wave and creating the phase lag. The 3D locomotion of this system are implemented by using the DNN to control the muscle lengths, and then using the muscle lengths to control the angles between two consecutive links on both horizontal and vertical planes. The test results show good performances of this model in both forward and backward locomotion in 3D, which could serve as a prototype of the micro-robot for clinical use. Show more

Keywords: C. elegans, dynamic neural networks, locomotion, 3D

DOI: 10.3233/BME-130839

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 529-537, 2014

Authors: Chen, Kan | Li, Bin | Tian, Lian-fang | Zhu, Wen-bo | Bao, Ying-han

Article Type: Research Article

Abstract: Pulmonary nodules are potential manifestation of lung cancer. Accurate segmentation of juxta-vascular nodules and ground glass opacity (GGO) nodules is an important and active area of research in medical image processing. At present, the classical active contour models (ACM) for segmentation of pulmonary nodules may cause the problem of boundary leakage. In order to solve the problem, a new fuzzy speed function–based active model for segmentation of pulmonary nodules is proposed in this paper. The fuzzy speed function incorporated into the ACM is calculated by the degree of membership based on intensity feature and local shape index. At the boundary …of pulmonary nodules, the fuzzy speed function approaches zero and the evolution of the contour curve will stop, so the accurate segmentation of pulmonary nodules can be obtained. Experimental results on juxta-vascular nodules and GGO nodules show that the proposed ACM can achieve accurate segmentation. Show more

Keywords: Image segmentation, boundary leakage, active contour models (ACM), fuzzy speed function, fuzzy clustering

DOI: 10.3233/BME-130840

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 539-547, 2014

Authors: Li, Jing | Ji, Zhenyu | Shi, Xuetao | You, Fusheng | Fu, Feng | Liu, Ruigang | Xia, Junying | Wang, Nan | Bai, Jing | Wang, Zhanxi | Qin, Xiansheng | Dong, Xiuzhen

Article Type: Research Article

Abstract: Skeletal muscle exhibiting complex and excellent precision has evolved for millions of years. Skeletal muscle has better performance and simpler structure compared with existing driving modes. Artificial muscle may be designed by analyzing and imitating properties and structure of skeletal muscle based on bionics, which has been focused on by bionic researchers, and a structure mode of linear electromagnetic array artificial muscle has been designed in this paper. Half sarcomere is the minimum unit of artificial muscle and electromagnetic model has been built. The structural parameters of artificial half sarcomere actuator were optimized to achieve better movement performance. Experimental results …show that artificial half sarcomere actuator possesses great motion performance such as high response speed, great acceleration, small weight and size, robustness, etc., which presents a promising application prospect of artificial half sarcomere actuator. Show more

Keywords: Artificial muscle, electromagnetic actuator, series-parallel array, multi-object optimization, finite element

DOI: 10.3233/BME-130841

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 549-555, 2014

Authors: Guo, Qiaohang | Zheng, Huang | Chen, Wenzhe | Chen, Zi

Article Type: Research Article

Abstract: Bistable structures, exemplified by the Venus flytrap and slap bracelets, can transit between different configurations upon certain external stimulation. Here we study, through three-dimensional finite element simulations, the bistable behaviors in elastic plates in the absence of terminate loads, but with pre-strains in one (or both) of the two composite layers. Both the scenarios with and without a given geometric mis-orientation angle are investigated, the results of which are consistent with recent theoretical and experimental studies. This work can open ample venues for programmable designs of plant/shell structures with large deformations, with applications in designing bio-inspired robotics for biomedical research …and morphing/deployable structures in aerospace engineering. Show more

Keywords: Bistability, elasticity theory, finite element analysis, geometric nonlinearity, biomimetic structures

DOI: 10.3233/BME-130842

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 557-562, 2014

Authors: Stasiak, Joanna | Nair, Sukumaran | Moggridge, Geoff D.

Article Type: Research Article

Abstract: The mechanical behavior of three styrenic thermoplastic block copolymer elastomers with applied surgical sutures was studied by uniaxial tensile testing. The materials exhibited oriented cylindrical microstructure. Distinct macroscopic deformation mechanisms have been observed upon stretching of samples with vertical and horizontal orientation. Deformation progressed along the axis of the suture in samples with parallel orientation (P), while it in case of normal orientation (N) the whole sample responded to the applied force. Also the analysis of the stress–strain curves showed a significant difference between samples P and N. Greater stress at break was observed for samples P, while samples N …showed the capability to tolerate higher strain. The influence of morphology on the tear-out shape has been also observed. The thread made a vertical tear out in samples P while for samples N ripping off the bottom was observed. Show more

Keywords: biomaterials, heart valves, sutures, mechanical behavior

DOI: 10.3233/BME-130843

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 563-569, 2014

Authors: Jang, Dong-Jin | Kim, Sung Tae | Oh, Euichaul | Ban, Eunmi

Article Type: Research Article

Abstract: To develop a solid dosage form of dutasteride for improving its oral bioavailability, a novel dry elixir (DE) system was fabricated. DEs incorporating dextrin and/or xanthan gum were prepared using spray-drying and evaluated by morphology, ethanol content, crystallinity, dissolution and oral bioavailability. DEs were spherical with a smooth surface and had an average particle size of 20–25 μm. The ethanol content could be easily varied by controlling the spray-drying temperature. The dissolution profiles of dutasteride from each DE proved to be much faster than that of dutasteride powder due to the amorphous state and a high amount of incorporated ethanol. …In particular, the pharmacokinetic profiles of dutasteride were significantly altered depending on the proportions of dextrin and xanthan gum. Blood concentrations of dutasteride from DE formulations were similar to those of market products and much greater than those of native dutasteride. Interestingly, the dissolution and pharmacokinetic profiles were easily controlled by changing the ratio of dextrin to xanthan gum. The data suggests that a DE using dextrin and/or xanthan gum could provide an applicable solid dosage form to improve the dissolution and bio-availability of dutasteride as well as to modulate its pharmacokinetics. Show more

Keywords: Dutasteride, dry elixir, xanthan gum, dissolution, oral bioavailability

DOI: 10.3233/BME-130844

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 571-579, 2014

Authors: Marin, E. | Offoiach, R. | Lanzutti, A. | Regis, M. | Fusi, S. | Fedrizzi, L.

Article Type: Research Article

Abstract: Titanium alloys are nowadays used for a wide range of biomedical applications thanks to their combination of high mechanical resistance, high corrosion resistance and biocompatibility. Nevertheless, the applicability of titanium alloys is sometimes limited due to their low microhardness and tribological resistance. Thus the titanium alloys cannot be successfully applied to prosthetic joint couplings. A wide range of surface treatments, in particular PVD coatings such as CrN and TiN, have been used in order to improve the tribological behaviour of titanium alloys. However, the low microhardness of the titanium substrate often results in coating failure due to cracks and delamination. …For this reason, hybrid technologies based on diffusive treatments and subsequent PVD coatings may improve the overall coating resistance. In this work, conventional PVD coatings of CrN or TiCN, deposited on Titanium Grade 5, were characterized and then combined with a standard thermal diffusive nitriding treatment in order to improve the tribological resistance of the titanium alloys and avoid coating delamination. The different treatments were studied by means of scanning electron microscopy both on the sample surface and in cross-section. In-depth composition profiles were obtained using glow discharge optical emission spectrometry (GDOES) and localized energy dispersive X-ray diffraction on linear scan-lines. The microhardness and adhesion properties of the different treatments were evaluated using Vickers microhardness tests at different load conditions. The indentations were observed by means of SEM in order to evaluate delaminated areas and the crack's shape and density. The tribological behaviour of the different treatments was tested in dry conditions and in solution, in alternate pin-on-flat configuration, with a frequency of 0.5 Hz. After testing, the surface was investigated by means of stylus profilometry and SEM both on the surface and in cross-section. The standalone PVD coatings show a limited tribological resistance due to the low hardness of the substrate, which results in fractures and delamination. The combination of a diffusive process and a subsequent PVD coating shows a stronger effect in improving the tribological resistance of the substrate. Show more

Keywords: Ti-6Al-4V, PVD, titanium hardening, nitridation, TiN

DOI: 10.3233/BME-130845

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 581-592, 2014

Authors: Noh, Dong K. | Lee, Nam G. | You, Joshua H.

Article Type: Research Article

Abstract: This study highlights a novel spinal kinematic analysis method and the feasibility of X-ray imaging measurements to accurately assess thoracic spine motion. The advanced X-ray Nash-Moe method and analysis were used to compute the segmental range of motion in thoracic vertebra pedicles in vivo. This Nash-Moe X-ray imaging method was compared with a standardized method using the Vicon 3-dimensional motion capture system. Linear regression analysis showed an excellent and significant correlation between the two methods (R2 = 0.99, p < 0.05), suggesting that the analysis of spinal segmental range of motion using X-ray imaging measurements was accurate and comparable …to the conventional 3-dimensional motion analysis system. Clinically, this novel finding is compelling evidence demonstrating that measurements with X-ray imaging are useful to accurately decipher pathological spinal alignment and movement impairments in idiopathic scoliosis (IS). Show more

Keywords: Accuracy, X-ray imaging, spinal kinematics, idiopathic scoliosis

DOI: 10.3233/BME-130846

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 593-598, 2014

Authors: Miao, Feng-qin | An, Yan-li | Yang, Rui | Tang, Qiu-sha | Zhang, Jian-qiong

Article Type: Research Article

Abstract: This paper aimed to investigate the preparation of doxorubicin-loaded bovine serum albumin nanoparticles (DOX/BSANP) and their effect on killing liver cancer cells in vitro and in vivo. DOX/BSANP was prepared using a desolvation-chemical crosslinking method. Their morphology and particle size were observed using transmission electron microscopy (TEM). The envelopment, drug-loading rates and slow-release characteristics were determined spectrophotometrically. Their ability to kill liver cancer cells in vitro was determined using the methyl thiazolyl tetrazolium (MTT) assay and flow cytometry (FCM). The tumor-suppressing effect of the nanoparticles in experimental animals in vivo was also evaluated. Under TEM, DOX/BSANP appeared spherical and was …distributed uniformly, with a diameter of about 120 nm and hydrated particle size of 170 nm determined by dynamic light diffraction. The envelopment rate was 82% and the drug-loading rate was 11.2%. The in vitro drug-release experiment showed that about 50% of the drug in drug-loaded nanoparticles was released continuously and slowly for 7 days. The MTT assay showed that DOX/BSANP significantly inhibited cell proliferation, while FCM showed that it induced tumor cell apoptosis. The in vivo tumor suppression test showed that the therapeutic effect of drug-loaded nanoparticles was superior to that of DOX alone. Show more

Keywords: DOX, albumin nanoparticles, desolvation-chemical crosslinking, liver cancer

DOI: 10.3233/BME-130847

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 599-607, 2014

Authors: Dlugosz, Tomasz

Article Type: Research Article

Abstract: The aim of this paper is to focus attention of experimenters on several sources of error that are not taken into account in the majority of bioelectromagnetics experiments, and which may lead to complete falsification of the results of the experiments.

Keywords: Electromagnetic field measurements, exposure systems, bioelectromagnetics studies, biomedical engineering

DOI: 10.3233/BME-130848

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 609-617, 2014

Authors: Li, Jia | Zheng, Wei | Pan, Ping | Sun, Xiaojun | Zhang, Yanfei

Article Type: Research Article

Abstract: In this paper, citric acid, 1,8-octanediol and 1,2-propanediol were used as reactive monomers to synthesize poly(1,2-propanediol-co-1,8-octanediol-co-citrate) (PPOC) elastomers by melt polycondensation. The PPOC elastomers were characterized by FTIR, 1H-NMR, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), hydrophilic test and mechanical test. The results indicated that citric acid had reacted with 1,8-octanediol and 1,2-propanediol, respectively. The sol content, swelling degree and hydrophilicity of PPOC elastomers increased with the higher content of 1,2-propanediol, while the tensile strength and the thermal degradation temperature decreased. The results indicate the addition of 1,2-propanediol reduces the crosslinking density and the flexibility of PPOC elastomers.

Keywords: Poly(1,2-propanediol-co-1,8-octanediol-co-citrate), 1,2-propanediol, elastomer

DOI: 10.3233/BME-130849

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 619-624, 2014

Authors: Wang, Xian-Kang | Ye, Jin-Duo | Gu, Fu-Shun | Wang, Ai-guo | Zhang, Chun-Qiu | Tian, Qian-Qian | Li, Xue | Dong, Li-Min

Article Type: Research Article

Abstract: In this paper, the single arm external fixation of intertrochanteric fracture healing process after surgery was simulated to obtain a postoperative fracture healing and stress distribution in the external fixator. Firstly CT images of intertrochanteric fracture are reconstructed into the femur solid model. Then based, the external fixator is installed on the model, which lastly formed a finite element model of unilateral external fixation for intertrochanteric fracture. The calculated results show: during the beginning of the fracture healing, there is much higher stress in both screws and femur in the model with solid screws than that in the model with …hollow screw. The stress of the femur in the model with hollow screw is more evenly. During the middle time of Fracture healing, stress in the femoral head significantly decreases. And the stress at fracture site gradually increased with the healing occurrence. According to the results, the authors designed hollow screws to use external fixation surgery. Surgery confirmed that the use of hollow screws in fractures treatment can satisfy the strength requirements, and can effectively reduce operative time, less patient suffering. The research for external fixation can provide a reference, and promote the use of external fixation hollow screws. Show more

Keywords: single arm external fixation, the femoral intertrochanteric fracture, stress distribution, numerical simulation, surgery scheme

DOI: 10.3233/BME-130850

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 625-632, 2014

Authors: Zhao, Peng | Deng, Cuijun | Xu, Hongzhen | Tang, Xing | He, Hailong | Lin, Chao | Su, Jiansheng

Article Type: Research Article

Abstract: Photo-crosslinked chitosan-gelatin scaffolds were fabricated and applied for chondrocyte culture in vitro. Photocurable methacryloyl chitosan was synthesized and characterized by FTIR and 1H NMR, respectively. Microstructure and mechanical properties of the chitosan-gelatin scaffold treated with or without EDC as crosslinking agent were analyzed by scanning electronic microscopy (SEM), compression and viscoelastic measurement. It is demonstrated that EDC-treated chitosan-gelatin scaffold possesses better porous structure and improved mechanical properties. Photo-crosslinked chitosan-gelatin scaffold could be further integrated in sodium alginate hydrogel using calcium chloride to support proliferation of chondrocytes for over 21 days and maintain spherical phenotype, as evaluated by AlamarBlue assay and …SEM, respectively, implying that the chitosan-gelatin-hydrogel system exhibits great cyto-biocompatibility. Results of this study show that photo-crosslinked chitosan-gelatin scaffold in sodium alginate hydrogel is suited as a scaffold candidate for cartilage tissue engineering. Show more

Keywords: chitosan, gelatin, chondrocyte, hydrogel, cartilage tissue engineering

DOI: 10.3233/BME-130851

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 633-641, 2014

Authors: Wang, Min | Ning, Yingyuan | Zou, Haixiao | Chen, Si | Bai, Yi | Wang, Aihua | Xia, Haibin

Article Type: Research Article

Abstract: Ti6Al4V discs with a thickness of 2.5 mm and dimensions of 15 × 15 mm2 were fabricated. The titanium nitride (TiN) surface was formed via Nd:YAG laser-nitriding. A sandblast acid-etched (SA) surface was used as a control. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and surface roughness tests were conducted to study the surface and cross-section morphologies as well as the properties of TiN and SA surfaces. MC3T3-E1 osteoblast-like cells were cultured on the TiN and SA surfaces to evaluate the effect of TiN surface on cellular behaviors, including attachment, proliferation and differentiation. Morphological testing results revealed that …the cross-section of TiN exhibited dendritic crystallization without cracking. The proliferation and differentiation of MC3T3-E1 cells on the laser-nitriding TiN surface were significantly increased compared to those cultured on SA surface. These findings suggested that the TiN surface generated from Nd:YAG laser-nitriding were favorable for the proliferation and differentiation of MC3T3-E1 cells, which is significant for implant surface modification. Show more

Keywords: laser-nitriding, TiN surface, MC3T3-E1 cells, adhesion, differentiation

DOI: 10.3233/BME-130852

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 643-649, 2014

Authors: Wang, Haiyan | Lin, Derong | Wang, Di | Hu, Lijiang | Huang, Yudong | Liu, Li | Loy, Douglas A.

Article Type: Research Article

Abstract: Sunscreens that absorb UV light without photodegradation could reduce skin cancer. Polyvinyl silsesquioxanes are known to have greater thermal and photochemical stability than organic compounds, such as those in sunscreens. This paper evaluates the UV transparency of vinyl silsesquioxanes (VS) and its hybrids with SiO2(VSTE) and TiO2(VSTT) experimentally and computationally. Based on films of VS prepared by sol-gel polymerization, using benzoyl peroxide as an initiator, vinyltrimethoxysilane (VMS) formulated oligomer through thermal curing. Similarly, VSTE films were prepared from VMS and 5–25 wt-% tetraethoxysilane (TEOS) and VSTT films were prepared from VMS and 5–25 wt-% titanium tetrabutoxide (TTB). Experimental average transparencies …of the modified films were found to be about 9–14% between 280–320 nm, 67–73% between 320–350nm, and 86–89% between 350–400nm. Computation of the band gap was absorption edges for the hybrids in excellent agreement with experimental data. VS, VSTE and VSTT showed good absorption in UV-C and UV-B range, but absorbed virtually no UV-A. Addition of SiO2 or TiO2 does not improve UV-B absorption, but on the opposite increases transparency of thin films to UV. This increase was validated with molecular simulations. Results show computational design can predict better sunscreens and reduce the effort of creating sunscreens that are capable of absorbing more UV-B and UV-A. Show more

Keywords: Silsesquioxane, silica, titanium dioxide, hybrid films, ultraviolet region, sunscreen, computation of band gap

DOI: 10.3233/BME-130853

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 651-657, 2014

Authors: Wu, Ming-Yue | Li, Quan-Li | Chen, Lian-Zi

Article Type: Research Article

Abstract: In this study, orthophosphoric acid (H3 PO4 ) in the treatment of porous titanium (Ti) is investigated and the ability of rat bone marrow stromal cells (BMSCs) is assessed to proliferate and differentiate on these modified surfaces in vitro. To improve the cytocompatibility of Ti surfaces, pure Ti was activated commercially by simple chemical pretreatment in H3 PO4 with different densities. Next, the phosphorylated specimens were soaked in simulated body fluid (SBF) to study the effect of biomineralization. The3-[4,5-dimethylthiazol-2-y1]-2, 5-diphenytetrazolium bromide (MTT) assay and the measurement of alkaline phosphatase (ALP) activity utilized to assess proliferation and differentiation of BMSCs …on exposure to modified Ti surfaces. Scanning electron microscopic (SEM) images showed that the surfaces of the pre-treated samples were characterized by a complex structure which consisted of a mesh-like morphological matrix and an uniform surface with different morphic crystals of titanium dihydrogen orthophosphate (Ti(H2 PO4 )3 ). These crystals contained hydroxyl with phosphate residues that resulted in biomineralization of cells. Therefore, BMSCs reveales a well-dispersed morphology on these modified and functionalized Ti surfaces. The viability and ALP activity of BMSCs on these altered biomimetic surfaces are found to be greater than those of the controls. It is concluded that the treatment of Ti by acid etching in orthophosphoric acid is a suitable method to enhance the in vitro proliferation and differentiation of BMSCs. Show more

Keywords: titanium implant, phosphorylation, cytocompatibility, stem cells, biomaterials, cellular engineering

DOI: 10.3233/BME-130854

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 659-671, 2014

Authors: Lin, Chao | Song, Yanyan | Lou, Bo | Zhao, Peng

Article Type: Research Article

Abstract: A dextranated, bioreducible cationic polyamide was designed and employed for non-viral gene delivery in vitro and in vivo. Initially, a new bioreducible cationic polyamide with p-nitrophenyl ester terminal group (denoted as SSBAP) was synthesized by polycondensation reaction of an excess amount of bis-(p-nitrophenyl)-3, 3'-dithiodipropanoate and 1, 4-bis(3-aminopropyl)piperazine. The SSBAP was then chemically conjugated with 5kDa amino-terminated dextran to yield dextran-SSBPA-dextran triblock copolymer (denoted as Dex-SSBAP-Dex). This copolymer was capable of binding genes to form nanoscale polyplexes with a near-neutral surface charge. Moreover, a sufficient gene release from the polyplexes in response to an intracellular reducing environment was observed. In vitro …transfection against MCF-7 and SKOV-3 cells showed that Dex-SSBAP-Dex copolymer effectively transfected the cells with comparable efficiency to that of 25kDa branched or linear polyethylenimine as positive controls. Besides, intravenous administration of the copolymer-based polyplexes in nude mice afforded detectable gene expression largely in the lung. Importantly, the copolymer revealed low cytotoxicity in vitro, as determined by AlamarBlue assay, and caused no death of the mice. Dextranated, bioreducible cationic polyamide holds high potential as a non-viral vector for gene delivery. Show more

Keywords: Dextran, disulfide, gene delivery, transfection, in vivo

DOI: 10.3233/BME-130855

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 673-682, 2014

Authors: Qu, Z.W. | Meng, Q.G. | Xiao, X. | Li, B.L. | Zhang, F.M.

Article Type: Research Article

Abstract: A high degree of cell adhesion to a scaffold at the initial stage of cell inoculation is essential to bone tissue engineering. In realising high cell adhesion rate on a scaffold within a few hours, a chitosan/hydroxyapatite (CS/HA) scaffold with a channel/sphere pore was prepared via in situ hybridisation in combination with lyophilisation, in which the HA nanoparticles were dispersed in the CS uniformly. The size of the channel pore and the sphere pore of the CS/HA scaffold was 150 μm to 650 μm and 3 μm to 15 μm, respectively. The compression strength and porosity of the CS/HA scaffold …were 3.54±0.32 MPa and 88.4%, respectively. The nitrogen content increased by 7.5% compared with the CS/HA scaffold without Arg-Gly-Asp (RGD) modification. More than 67% of the RGD in the PBS solution diffused into the CS/HA scaffold spontaneously. The effect of the RGD peptide on bone marrow mesenchymal stem cells (MSCs) on the CS/HA scaffold was investigated through cell adhesion rate, alkaline phosphatase (ALP) activity, and mineralised calcium nodules. The cell adhesion rates of the CS/HA scaffold with different RGD concentrations (50, 100 mg/L) were 71.6% and 80.7%, respectively, after 4 hours of culture; the rates were 30.9% and 47.5% higher than that of the CS/HA group (54.7%), respectively. The expressed ALP content of the CS/HA scaffold with RGD (191±6 U/g protein) was 107.7% higher than that (92±9U/g protein) of CS/HA (p<0.01). Furthermore, a higher amount of mineralised calcium nodules with red brown appeared in the CS/HA scaffold with RGD as opposed to that in the CS/HA group. The RGD peptide in the CS/HA scaffold not only achieved high cell adhesion in a short period of time, but also enhanced cell adhesion ability and promoted the MSCs to differentiate from osteoblasts. Show more

Keywords: RGD peptides, Chitosan, Hydroxyapatite, Bone Marrow Mesenchymal Cells, Tissue engineering

DOI: 10.3233/BME-130856

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 683-693, 2014