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

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