Key Laboratory for Biomedical Engineering

Hangzhou, China

Key Laboratory for Biomedical Engineering

Hangzhou, China
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Zhang C.,Key Laboratory for Biomedical Engineering | Zhang C.,Zhejiang Prov Key Laboratory Of Cardio Cerebr Vasc Detection Technology And Med Effectiveness Appraisal | Gao C.,Key Laboratory for Biomedical Engineering | Chang M.-W.,Key Laboratory for Biomedical Engineering | And 3 more authors.
Applied Physics Letters | Year: 2016

Electrospinning (ES) enables simple production of fibers for broad applications (e.g., biomedical engineering, energy storage, and electronics). However, resulting structures are predominantly random; displaying significant disordered fiber entanglement, which inevitably gives rise to structural variations and reproducibility on the micron scale. Surface and structural features on this scale are critical for biomaterials, tissue engineering, and pharmaceutical sciences. In this letter, a modified ES technique using a rotating multi-nozzle emitter is developed and utilized to fabricate continuous micron-scaled polycaprolactone (PCL) ropes, providing control on fiber intercalation (twist) and structural order. Micron-scaled ropes comprising 312 twists per millimeter are generated, and rope diameter and pitch length are regulated using polymer concentration and process parameters. Electric field simulations confirm vector and distribution mechanisms, which influence fiber orientation and deposition during the process. The modified fabrication system provides much needed control on reproducibility and fiber entanglement which is crucial for electrospun biomedical materials. © 2016 Author(s).

Wu J.,Zhejiang University | Wu J.,Zhejiang Prov Key Laboratory Of Cardio Cerebr Vasc Detection Technology And Med Effectiveness Appraisal | Wu J.,Key Laboratory for Biomedical Engineering | Xu Y.,Zhejiang University | And 7 more authors.
Computational and Mathematical Methods in Medicine | Year: 2015

Quantitative analysis of the dynamic behavior about membrane-bound secretory vesicles has proven to be important in biological research. This paper proposes a novel approach to automatically identify the elusive fusion events between VAMP2-pHluorin labeled GLUT4 storage vesicles (GSVs) and the plasma membrane. The differentiation is implemented to detect the initiation of fusion events by modified forward subtraction of consecutive frames in the TIRFM image sequence. Spatially connected pixels in difference images brighter than a specified adaptive threshold are grouped into a distinct fusion spot. The vesicles are located at the intensity-weighted centroid of their fusion spots. To reveal the true in vivo nature of a fusion event, 2D Gaussian fitting for the fusion spot is used to derive the intensity-weighted centroid and the spot size during the fusion process. The fusion event and its termination can be determined according to the change of spot size. The method is evaluated on real experiment data with ground truth annotated by expert cell biologists. The evaluation results show that it can achieve relatively high accuracy comparing favorably to the manual analysis, yet at a small fraction of time. © 2015 Jian Wu et al.

Liu P.-F.,Zhejiang University | Liu P.-F.,Key Laboratory for Biomedical Engineering | Liu J.-Q.,Zhejiang University | Liu J.-Q.,Key Laboratory for Biomedical Engineering | And 2 more authors.
Chinese Journal of Biomedical Engineering | Year: 2012

Finite element modeling (FEM) method has been utilized as a numerical tool to determine the temperature distribution and lesion size in studies of cardiac radiofrequency (RF) catheter ablation. However, most ablation models are very simple and none of the previous FEM analyses take heart chamber anatomy into account. In this paper, a novel method was proposed to perform FEM analysis based on cardiac CT data. A detailed cardiac ablation model was created based on CT heart inner surface mesh, and various electrode positions were specified by user selection. Then COMSOL scripts were called by Matlab to perform FEM analysis. Pennes heat transfer equation was adopted and 50°C was set as criteria for lesion size determination. The temperature profile and ablation lesion size were estimated. The simulation results revealed that the ablation lesion region shape was not totally symmetric due to the asymmetric heart chamber surface and varied with electrode insertion angles and penetration depths. Lesion region size had a positive correlation with angles and depths. The proposed method can achieve specified ablation result based on heart anatomy.

Wang B.,Zhejiang University | Wang B.,Key Laboratory for Biomedical Engineering | Hu W.,Zhejiang University | Liu J.,Zhejiang University | And 4 more authors.
Computational and Mathematical Methods in Medicine | Year: 2014

Gastroscopic examination is one of the most common methods for gastric disease diagnosis. In this paper, a multitarget tracking approach is proposed to assist endoscopists in identifying lesions under gastroscopy. This approach analyzes numerous preobserved gastroscopic images and constructs a gastroscopic image graph. In this way, the deformation registration between gastroscopic images is regarded as a graph search problem. During the procedure, the endoscopist marks suspicious lesions on the screen and the graph is utilized to locate and display the lesions in the appropriate frames based on the calculated registration model. Compared to traditional gastroscopic lesion surveillance methods (e.g., tattooing or probe-based optical biopsy), this approach is noninvasive and does not require additional instruments. In order to assess and quantify the performance, this approach was applied to stomach phantom data and in vivo data. The clinical experimental results demonstrated that the accuracy at angularis, antral, and stomach body was 6.3 ± 2.4 mm, 7.6 ± 3.1 mm, and 7.9 ± 1.6 mm, respectively. The mean accuracy was 7.31 mm, average targeting time was 56 ms, and the P value was 0.032, which makes it an attractive candidate for clinical practice. Furthermore, this approach provides a significant reference for endoscopic target tracking of other soft tissue organs. © 2014 Bin Wang et al.

Sun D.,Zhejiang University | Sun D.,Key Laboratory for Biomedical Engineering | Hu W.,Zhejiang University | Wu W.,Zhejiang University | And 6 more authors.
Journal of Medical Systems | Year: 2012

Endoscopists currently rely on an invasive biopsy tattooing method to identify previously biopsied sites. In order to better guide endoscopists to find the biopsy positions in follow-ups, we proposed a non-invasive image guided biopsy marking system for gastroscopy. Using an electromagnetic tracking device, the position of the gastroscope relative to the stomach was acquired and displayed in the guidance interface. The biopsy positions were recorded in computer for the use of guidance in follow-ups. The accuracy of the system was evaluated by both phantom experiments and in vivo experiments. The average target registration errors on the test animal and the volunteer are 13.4 mm and 11.2 mm respectively. Although the positioning error is slightly larger than current biopsy tattooing method, it satisfies the need for guidance. In the near future, we will validate the system by measuring how much it saves examination time. © 2011 Springer Science+Business Media, LLC.

Liu J.,Zhejiang University | Liu J.,Rochester College | Liu J.,Key Laboratory for Biomedical Engineering | Rettmann M.E.,Rochester College | And 4 more authors.
Computerized Medical Imaging and Graphics | Year: 2011

Accurate and fast fusion and display of real-time images of anatomy and associated data is critical for effective use in image guided procedures, including image guided cardiac catheter ablation. We have developed a piecewise patch-to-model matching method, a modification of the contractive projection point technique, for accurate and rapid matching between an intra-operative cardiac surface patch and a pre-operative cardiac surface model. Our method addresses the problems of fusing multi-modality images and using non-rigid deformation between a surface patch and a surface model. A projection lookup table, K-nearest neighborhood search, and a final iteration of point-to-projection are used to reliably find the surface correspondence. Experimental results demonstrate that the method is fast, accurate and robust for real-time matching of intra-operative surface patches to pre-operative 3D surface models of the left atrium. © 2011 Elsevier Ltd.

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