Bio-Medical Materials and Engineering - Volume 24, issue 6

Authors: Yao, Li | Xu, Hui | Li, Andong

Article Type: Research Article

Abstract: The Kinect-based physical rehabilitation receives increasing recognition as an approach to provide convenience for the patients who need the therapy usually from the health professions. Most of the previous studies were driven from the patients' point of view. This paper proposes a system aiming to simplify the recovery instruction from therapists, increasing patients' motivation to participate in the rehabilitation exercise. Furthermore, the architecture for developing such rehabilitation system is designed by motion capture, human action recognition and standard exercises prototype with Kinect device.

Keywords: Rehabilitation, kinect, motion capture, therapist-oriented

DOI: 10.3233/BME-141077

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2611-2618, 2014

Authors: Kazembakhshi, Siamak | Luo, Yunhua

Article Type: Research Article

Abstract: Image-based finite element (FE) modeling of human bones has been increasingly applied as a useful tool in biomedical engineering. However, most existing image-based FE models assume isotropic mechanical properties for bones, although bones are typically anisotropic material. In this study, we attempted to construct anisotropic FE models from medical computed tomography (CT) scans by modifying the existing empirical relations of bone elasticity-density. The hypothesis adopted in the study is that bone anisotropy is generated by the variations of bone density and the proposed anisotropic relations should degenerate to the isotropic ones if bone density variation is taken zero. The effect …of considering bone anisotropy in FE models was investigated by numerical studies. The obtained numerical results showed that the relative error in the finite element solutions produced respectively by the isotropic and anisotropic FE models can be as large as 50%. We concluded from this preliminary study that the consideration of anisotropy in bone FE models has a significant effect on the accuracy of bone behavior predicted by the FE models. However, well-designed bone tests have to be conducted to validate the anisotropic bone elasticity-density relation proposed in this study. Show more

Keywords: bone, finite element model, computed tomography, anisotropy, elasticity modulus

DOI: 10.3233/BME-141078

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2619-2626, 2014

Authors: Zhang, Yi | Shi, Tingchun

Article Type: Research Article

Abstract: Larynx has a complex structure with joints and multiple functions. In order to study the artificial larynx and artificial auricle scaffold, a three-dimensional digital model of laryngeal joint is established in this paper using MIMICS with its biomechanical properties analyzed and calculated by using the finite element method. This model is based on the CT scanned images of 281 layers with an interlamellar spacing of 1.25 mm. The obtained data are denoised, segmented and smoothed before being loaded into MIMICS. By further optimizations, an accurate and complete 3D model can be obtained. Subsequently, a 3D FEM of the normal larynx …joint is performed which allows observations from any dimensions and angles. Compared with natural laryngeal joint, this model has good geometric similarity and mechanically similar throat voicing functions. Show more

Keywords: laryngeal joints, finite element, laryngeal reconstruction, three-dimensional reconstruction

DOI: 10.3233/BME-141079

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2627-2634, 2014

Authors: Zhang, Mingming | Zhao, Zongya | He, Ping | Wang, Jue

Article Type: Research Article

Abstract: Gap junctions are the mechanism for striatal fast-spiking interneurons (FSIs) to interconnect with each other and play an important role in determining the physiological functioning of the FSIs. To investigate the effect of gap junctions on the firing activities and synchronization of the network for different external inputs, a simple network with least connections and a Newman-Watts small-world network were constructed. Our research shows that both properties of neural networks are related to the conductance of the gap junctions, as well as the frequency and correlation of the external inputs. The effect of gap junctions on the synchronization of network …is different for inputs with different frequencies and correlations. The addition of gap junctions can promote the network synchrony in some conditions but suppress it in others, and they can inhibit the firing activities in most cases. Both the firing rate and synchronization of the network increase along with the increase of the electrical coupling strength for inputs with low frequency and high correlation. Thus, the network of coupled FSIs can act as a detector for synchronous synaptic input from cortex and thalamus. Show more

Keywords: Network, fast-spiking interneurons, synchronization, firing rate, small-world

DOI: 10.3233/BME-141080

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2635-2644, 2014

Authors: Bai, Long | Cui, Yuhong | Zhang, Yixia | Zhao, Na

Article Type: Research Article

Abstract: The mechanical behavior of blood cells in the vessels has a close relationship with the physical characteristics of the blood and the cells. In this paper, a numerical simulation method was proposed to understand a single-blood cell's behavior in the vessels based on fluid-solid interaction method, which was conducted under adaptive time step and fixed time step, respectively. The main programme was C++ codes, which called FLUENT and ANSYS software, and UDF and APDL acted as a messenger to connect FLUENT and ANSYS for exchanging data. The computing results show: (1) the blood cell moved towards the bottom of the …flow chamber in the beginning due to the influence of gravity, then it began to jump up when reached a certain height rather than touching the bottom. It could move downwards again after jump up, the blood cell could keep this way of moving like dancing continuously in the vessels; (2) the blood cell was rolling and deforming all the time; the rotation had oscillatory changes and the deformation became conspicuously when the blood cell was dancing. This new simulation method and results can be widely used in the researches of cytology, blood, cells, etc. Show more

Keywords: Fluid-solid interaction, numerical simulation, jumping, rolling, deformation

DOI: 10.3233/BME-141081

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2645-2655, 2014

Authors: Li, Kun | Zhang, Song | Yang, Lin | Luo, Zhichang | Gu, Guanxiong

Article Type: Research Article

Abstract: Objective: There are many similarities between the photoplethysmography(PPG) pulse wave and the radial pulse when a body is in a stationary state, but the difference between them under conditions of movement is not yet clear. Finding these differences may help further understanding of the cardiovascular system. Methods: PPG and radial pulse wave were recorded simultaneously while subjects were conducting a bicycle exercise test that included the resting and exercise state, while the K and K' parameters were being acquired from the PPG and radial pulse, respectively. Furthermore, the pulse objective pattern is observed via the time domain waveform and XY …graph. Results: When the body's state of movement changes dramatically, there is a time difference between the pulse parameter K and the pulse amplitude, and the difference of the pulse pattern is enhanced during the exercising phase. Conclusion: Radial pulse waves are not the same as PPG during exercise in either the pulse parameter or the pulse pattern. This information can be used to further evaluate the state of arterial circulation and microcirculation. Show more

Keywords: photoplethysmography(PPG), radial pulse wave, waveform parameter, waveform pattern

DOI: 10.3233/BME-141082

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2657-2664, 2014

Authors: Zhao, Zijian

Article Type: Research Article

Abstract: Robotized endoscope holder in laparoscopic surgeries allows surgeons to control the endoscope without the assistants' intervention. In this paper, a new method is proposed for the automatic 3D-tracking of laparoscopic instruments in real-time to provide more convenient interactions between surgeons and the robotized endoscope holder. The method is based on the 3D position measurements of the insertion points of the instruments and the strip markers, combined with the depth estimation of the instruments. The results of our experiments show that our method is fast and robust in the simulated laparoscopic surgeries.

Keywords: Laparoscopic surgery, tool tracking, localization of instrument, robotized camera holder

DOI: 10.3233/BME-141083

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2665-2672, 2014

Authors: Liu, Jiquan | Wang, Bin | Hu, Weiling | Zong, Yun | Si, Jianmin | Duan, Huilong

Article Type: Research Article

Abstract: Biopsy is a traditional endoscopic surveillance of premalignant gastric lesions, and endoscopic tattooing is used for marking the biopsy's location. However, the tattooing has several disadvantages. For example, the procedure is an invasive operation and may not be durable due to the diffusion. Moreover, it is procedurally cumbersome with an associated risk of technical failure. In this study, a computer aided endoscopic navigation system (CAEN system) was developed for a non-invasive biopsy procedure. The CAEN system consists of a new, designed six degree of freedom (6-DOF) tracking endoscope device and a computer simulated work station. During the procedure, the endoscopist …uses the tip of the tracking endoscope to touch the lesion. Then, the lesion's location is recorded in the work station, which then guides the endoscopist in retargeting the lesions in the follow-ups. The clinical experimental results demonstrate that the accuracy at the angularis is 5.2±2.8 mm, at the antral lesser curvature is 7.2±2.0 mm, at the antral greater curvature is 6.3±3.1 mm, at the antral posterior wall is 8.2±1.6 mm, and at the antral anterior wall is 7.9±1.3 mm. The mean accuracy is 7.5 mm, and the P-value is 0.023, which is likely suitable for clinical practice. Furthermore, the proposed CAEN system requires less procedural time than the tattooing. Show more

Keywords: Endoscopic biopsy marking, non-invasive procedure, 6-DOF endoscope device, hand-eye calibration, computer simulated work station

DOI: 10.3233/BME-141084

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2673-2679, 2014

Authors: Kim, Ji-Won | Kwon, Yuri | Jeon, Hyung-Min | Bang, Min-Jung | Jun, Jae-Hoon | Eom, Gwang-Moon | Lim, Do-Hyung

Article Type: Research Article

Abstract: The purpose of this study was to investigate 1) the effect of feet distance on static postural balance and 2) the location of natural feet distance and its possible role in the relationship of feet distance and postural balance. Static balance tests were performed on a force platform for 100 s with six different feet distances (0, 5, 10, 15, 20, 25 cm). Measures of postural balance included mean amplitude of horizontal ground reaction force (GRF) as well as the mean distance and velocity of the center of pressure (COP). All measures were discomposed into anterioposterior and mediolateral directions. ANOVA …and post-hoc comparison were performed for all measures with feet distance as an independent factor. Also measured was the feet distance at the natural stance preferred by each subject. All measures significantly varied with feet distance (p<0.001). Mean distance of COP showed monotonic decrease with feet distance. Mean amplitude of horizontal GRF as well as mean velocity of COP showed U-shaped pattern (decrease followed by increase) with the minimum at the feet distance of 15cm or 20 cm, near which the natural feet distance of 16.5 (SD 3.8) cm was located. COP is regarded to be an approximation of the center of mass (hence the resultant performance of postural control) in an inverted pendulum model with the horizontal GRF ignored. On the other hand, horizontal GRF is the direct cause of horizontal acceleration of a center of mass. The present result on horizontal GRF shows that the effort of postural control is minimized around the feet distance of natural standing and implies why the natural stance is preferred. Show more

Keywords: Stance width, postural stability, preferred stance, center of pressure, ground reaction force

DOI: 10.3233/BME-141085

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2681-2688, 2014

Authors: Lee, Wei-chen | Huang, Ching-Hang | Chung, Shan-Chen | Wei, Ching-chih

Article Type: Research Article

Abstract: The aim of this research was to develop an efficient and accurate method to fabricate a dental implant surgical guide. The surgical guide is adapted from the patient's vacuum-formed clear template with the use of a plate with three ceramic balls, a six-axis drilling machine and its fixture. The plate, with the ceramic balls used as radiographic markers, is glued to the template, and the patient bites this template during a CT scan. Then, the surgeon can plan the locations and orientations of the implants on the CT-based model in the dental planning software. The drilling information is exported directly …to the computer-controlled drilling machine for subsequent drilling on the template to complete the surgical guide. This method allows the surgical guide to be made without any measurements, which reduces the fabrication time, but increases the drilling accuracy. The preliminary results show that the average location error was 0.31 ± 0.17 mm and the average orientation error was 0.53 ± 0.24° , which can be considered accurate in comparison with the results reported in the literature. Show more

Keywords: Dental implant surgical guide, drilling machine, radiographic marker, fixture, vacuum-formed template

DOI: 10.3233/BME-141086

Citation: Bio-Medical Materials and Engineering, vol. 24, no. 6, pp. 2689-2695, 2014