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

Authors: Du, Dongxing | Jiang, Song | Wang, Ze | Hu, Yingying | He, Zhaoming

Article Type: Research Article

Abstract: Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two …jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER. Show more

Keywords: Left ventricular, mitral valve, edge to edge repair (ETER), vortex, atrio-ventricular pressure, wall shear stress

DOI: 10.3233/BME-130795

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 155-161, 2014

Authors: Li, Li | Hu, Wen-yong | Liu, Li-zhi | Pang, Ya-chun | Shao, Yuan-zhi

Article Type: Research Article

Abstract: Multifractal spectrum analysis of dynamic contrast enhanced (DCE) breast MR images was used to establish a new quantitative analysis method for solid tumor blood perfusion and to explore its applicability in evaluating efficacy of breast cancer chemotherapy. Five randomly selected patients suffering from newly diagnosed malignant breast nodule lesions were enrolled in this study, and four of them were treated with neoadjuvant chemotherapy. Their DCE breast MR images were collected before and after treatment. Chemotherapeutic efficacy was analyzed using international response evaluation criteria for solid tumors (RECIST). Sandbox method for statistical number density was employed to measure and calculate multifractal …spectra of DCE breast MR images with spatiotemporal characteristics. Multifractal spectral data of malignant lesions before and after chemotherapy were compared. Multifractal spectra of malignant lesions show an asymmetric bell-shape. Chemotherapy efficacy was assessed to be partial remission (PR) for three patients and their multifractal spectral width significantly increased after chemotherapy while to be stable disease (SD) for other patient and of her changed slightly. Multifractal spectral width correlates with blood-supply condition of tumor lesion before and after chemotherapy, providing a potential suitable characteristic parameter for evaluating chemotherapeutic efficacy quantitatively. Show more

Keywords: Breast cancer, magnetic resonance imaging, multifractal spectrum, image processing

DOI: 10.3233/BME-130796

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 163-171, 2014

Authors: Zhang, Hong-Yu | Zhou, Ming

Article Type: Research Article

Abstract: The stem-cement interface in total hip replacement experiences fretting wear following debonding under cyclical physiological loading. However, the influence of protein concentration on the biotribological properties of this interface has not been well taken into consideration. In the present study, a series of fretting frictional tests were performed using polished Ti6Al4V and bone cement, lubricated by bovine serum albumin solutions of different concentrations (5%, 30%, and 75%). Surface characterizations of Ti6Al4V pins were conducted by optical interferometer, scanning electron microscope, and Raman spectroscopy. The results show that the friction coefficient decreases with the increase of protein concentration, although the difference …is not significant. In addition, bovine serum albumin is adsorbed onto Ti6Al4V surface, forming a protective film to prevent the metal substrate from wear. The elemental and spectroscopic analyses of the film confirm the presence of protein molecules adsorbed on Ti6Al4V surface, with a thickness of 2.5 μm. It is indicated from this study that fretting wear at the stem-cement interface can be postponed by promotion of protein adsorption on the metal surface. Show more

Keywords: stem-cement interface, biotribology, surface characterization, protein adsorption, bovine serum albumin

DOI: 10.3233/BME-130797

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 173-179, 2014

Authors: Zhou, Zhong-yun | Chen, Yi-qing | Wang, Fei-yan | Tian, Nan | Fan, Chun-lei

Article Type: Research Article

Abstract: This study was designed to investigate the effect of curcumin on the expression of thrombospondin-4 (THBS-4) in mouse macrophages treated with oxidized low-density lipoprotein (oxLDL). The mouse macrophage cell line ANA-1 was treated with oxLDL. Cell viability was measured by MTT assay. ANA-1 cells were divided into five groups: control group, model group, 5 μM curcumin group, 15 μM curcumin group and 25 μM curcumin group. The gene and protein expression levels of THBS-4 in each group were determined by real-time quantitative polymerase chain reaction (PCR) and western blotting, respectively. MTT assay showed that curcumin concentrations up to 25 μM …and oxLDL concentrations up to 20 μg/ml had no significant cytotoxic effects on macrophages at 24 h. Real-time quantitative PCR revealed that THBS-4 mRNA expression was markedly reduced by stimulation with oxLDL, but subsequently significantly increased by treatment with curcumin. Western blotting confirmed that curcumin (5, 15, and 25 μM) significantly prevented the decrease in THBS-4 expression induced by oxLDL (20 μg/ml) in macrophages. Curcumin prevents the decrease in THBS-4 expression induced by oxLDL, which may represent one of the anti-atherosclerotic mechanisms of curcumin. Show more

Keywords: Curcumin, thrombospondin-4, atherosclerosis, oxidized low-density lipoprotein, angiogenesis

DOI: 10.3233/BME-130798

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 181-189, 2014

Authors: Pei, Bao-Qing | Li, Hui | Li, De-Yu | Fan, Yu-Bo | Wang, Chuan | Wu, Shu-Qin

Article Type: Research Article

Abstract: The internal hydrostatic pressure (IHP) of the intervertebral disc is the functional and physiological basis of the spine. Disc bulging is a direct effect of increased IHP and can be used to evaluate the IHP without destroying the structure of the disc. Disc tissue engineering is a developing field but more data on the properties of normal discs are required for evaluation of possible graft materials. However, very little data is available concerning bulge distribution along the normal disc surface under creep. Methods: Fifteen motion segment specimens of ovine IVD were used to analyze axial creep, and disc bulging …deformations of 5 markers on the surface were measured and analyzed. Findings: The maximum radial bulging rate was 2.78%±1.09% and the position at which the maximum radial deformation occurred was found to be below the midline of the disc during all levels of loading. The results showed that deformations occurred in the order vertical, radial, circumferential. Interpretation: Disc bulging during creep is a very important biomechanical response, affecting spinal functions. The deformation regularities of the disc surface were identified and may help supply important basic data for disc tissue engineering. Show more

Keywords: Disc bulging, surface distribution deformation, compressive creep

DOI: 10.3233/BME-130799

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 191-198, 2014

Authors: Chew, Kim Mey | Sudirman, Rubita | Seman, Norhudah | Yong, Ching Yee

Article Type: Research Article

Abstract: The study was conducted based on two objectives as framework. The first objective is to determine the point of microwave signal reflection while penetrating into the simulation models and, the second objective is to analyze the reflection pattern when the signal penetrate into the layers with different relative permittivity, εr . Thus, several microwave models were developed to make a close proximity of the in vivo human brain. The study proposed two different layers on two different characteristics models. The radii on the second layer and the corresponding antenna positions are the factors for both models. The radii for model …1 is 60 mm with an antenna position of 10 mm away, in contrast, model 2 is 10 mm larger in size with a closely adapted antenna without any gap. The layers of the models were developed with different combination of materials such as Oil, Sandy Soil, Brain, Glycerin and Water. Results show the combination of Glycerin + Brain and Brain + Sandy Soil are the best proximity of the in vivo human brain grey and white matter. The results could benefit subsequent studies for further enhancement and development of the models. Show more

Keywords: microwave signal, human-like phantom, relative permittivity, reflection coefficient, computer simulation technology

DOI: 10.3233/BME-130800

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 199-207, 2014

Authors: Su, Fangming | Li, Zhaoxi | Sun, Xiurong | Han, Nan | Wang, Lei | Luo, Xiaomin

Article Type: Research Article

Abstract: Objective: Normal pregnancy is associated with profound alterations in the maternal cardiovascular system and PPG represents a sensitive and convenient technique capable of tracking changes in the pulsatile function of arteries. The aim of this study was to investigate the effects of maternal cardiovascular alterations on the finger tip photoplethysmography (PPG) during normal gestation. Methods: Thirty five healthy pregnant women were studied at each trimester of pregnancy and again on gestational age using PPG signals, peripheral blood pressure (BP) and heart rate (HR). Results: Comparing with nonpregnant controls, several characteristic differences in PPG derived parameters and morphologies occurred …in the pregnant. PAI, RI, PTT as well as AUC1 and Y1 of bcAUC1 were different and significant difference had been found in second and third trimester, despite little change in the peripheral blood pressure. The mean heart rate increased linearly with gestational age. Conclusion: This study has confirmed that normal pregnancy is associated with profound alterations in PPG signals occurred principally as a result of maternal cardiovascular adaptation and PPG-based noninvasive assessment of cardiovascular activities is feasible throughout pregnancy. Using this technique we demonstrated a delay in wave reflection within the arterial tree and a reduction in magnitude of arterial wave reflections in normal pregnancy which is consistent with previous observations and the known cardiovascular changes of pregnancy. Show more

Keywords: photoplethysmographic signal, maternal cardiovascular adaptation, gestational age, pulse appearance, waveform morphology

DOI: 10.3233/BME-130801

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 209-219, 2014

Authors: Zhao, Yaqian | Zhao, Qinping | Hao, Aimin

Article Type: Research Article

Abstract: Multimodal medical image fusion is a method of integrating information from multiple image formats. Its aim is to provide useful and accurate information for doctors. Multi-channel pulse coupled neural network (m-PCNN) is a recently proposed fusion model. Compared with previous methods, this network can effectively manage various types of medical images. However, it has two drawbacks: lack of control to feed function and low-level automation. The improved multi-channel PCNN proposed in this paper can adjust the impact of feed function by linking strength and adaptively compute the weighting coefficients for each pixel. Experimental results demonstrated the effectiveness of the improved …m-PCNN fusion model. Show more

Keywords: Multimodal medical image fusion, pulse coupled neural network, multi-channel PCNN

DOI: 10.3233/BME-130802

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 221-228, 2014

Authors: Zheng, W. | Ma, J.Y. | Guo, F. | Li, J. | Zhou, H.M. | Xu, X.X. | Li, L. | Zheng, Y.F.

Article Type: Research Article

Abstract: The paper demonstrates a novel glucose/O2 biofuel cell (BFC) based on the electrospun collagen-SWNTs nanofibres with the glucose oxidase (GOD) as the anodic biocatalysts and the laccase as the cathodic biocatalysts. With an average diameter of about (260±95) nm, the electrospun collagen-SWNTs nanofibres exhibited smooth surfaces. The collagen-SWNTs nanofibres modified electrode showed good electron transfer behavior, because of the properties of SWNTs and the three-dimensional reticular structure of the electrospun nanofibers. The GOD and laccase, immobilized in the collagen-SWNTs nanofibres, exhibited good catalytic activity towards glucose oxidation and oxygen reduction through mediators of ferrocene monocarboxylic acid (FMCA) and 2,2'-azinobis …(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS), respectively. The maximum power density of the assembled glucose/O2 BFC based on the electrospun collagen-SWNTs nanofibres was ca. 14.3 μW/cm2 . Moreover, more than 50% of the initial value remained after continuous operation of 100 h. The results indicated the potential to apply the electrospun collagen-SWNTs nanofibres for novel BFC device. Show more

Keywords: Electrospun, collagen-SWNTs nanofibres, glucose oxidase, laccase, biofuel cell

DOI: 10.3233/BME-130803

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 229-235, 2014

Authors: Liu, Anan | Gao, Zan | Tong, Hao | Su, Yuting | Yang, Zhaoxuan

Article Type: Research Article

Abstract: Automated human larynx carcinoma (HEp-2) cell classification is critical for medical diagnosis. In this paper, we propose a sparse coding-based unsupervised transfer learning method for HEp-2 cell classification. First, the low level image feature is extracted for visual representation. Second, a sparse coding scheme with the Elastic Net penalized convex objective function is proposed for unsupervised feature learning. At last, a Support Vector Machine classifier is utilized for model learning and predicting. To our knowledge, this work is the first to transfer the human-crafted visual feature, sensitive to the variation of appearance and shape during cell movement, to the high …level representation which directly denotes the correlation of one sample and the bases in the learnt dictionary. Therefore, the proposed method can overcome the difficulty in discriminative feature formulation for different kinds of cells with irregular and changing visual patterns. Large scale comparison experiments will be conducted to show the superiority of this method. Show more

Keywords: HEp-2 cell, cell classification, transfer learning, sparse coding, elastic net

DOI: 10.3233/BME-130804

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 1, pp. 237-243, 2014