摘要：Objective: Prepare cross-linked HA gels with higher mechanical stability,lower degradation velocity and desirable biocompatibility,so as to extend the usage of HA.Method: 1.Test molecular weight of HA (MrHA) by viscosimetry;2.Prepare cross-linked HA gels by DVS,GTA,DEC;3.Discuss the cross-linking and degradation procedure;4,evaluate the biocompatibility of the best HA gels.Results: The mechanical stability and durability to degradation of HA-DVS gels are superior to those of other gels,and when HA :DVS = 40:1 (g/g),at 35℃ and in 0.2M NaOH solution,the HA-DVS gel shows the best mechanical stability,and its cytotoxicity reaches class I,hemolysis ratio is lower than 5 %.Conclusion:Our HADVS gel can be used to prepare biologic scaffolds.

摘要：Objective: Medical equipment safety in clinical use has been an increasingly concerned issue in China. This paper aims to design and implement a web-based medical equipment maintenance system to be used at clinical engineering department, orienting to the improvement of quality and efficiency of technology service so as to meet the 2010 regulations homologated with China's Ministry of Health. Methods:The system adopted three-layer structure based on B/S mode with oracle database and ASP.NET development technologies. Based on risk management and inclusion criteria for maintenance, the software system modules consist of hospital equipment inventory management, personnel information management, breakdown maintenance, preventive maintenance (PM) and analysis graphical representations. Results:An user friendly web interface was provided for easy and secure access to the system. Medical equipment management activities from log-in to acceptance test to maintenance services were implemented. Conclusion:The application of this system has achieved benefits for the risk management of medical equipment.

摘要：A portable and comfortable wireless ECG monitoring system composed of fabric electrodes and a monitoring terminal was proposed,which is essential to continuous ECG monitoring.The ECG signal acquired could be processed and stored in the monitoring terminal.The HR was got and transmitted to any devices through a Bluetooth interface.The experimental results in resting and walking showed that the ECG monitoring system could acquire the ECG signal steadily,continuously and precisely.

摘要：In order to understand the development of stem cells into specialized mature cells it is necessary to study the growth of cells in culture. For this purpose it is very useful to have an efficient computerized cell tracking system. In this paper a prototype system for tracking neural stem cells in a sequence of images is described. In order to get reliable tracking results it is important to have good and robust segmentation of the cells. To achieve this we have implemented three levels of segmentation. The primary level, applied to all frames, is based on fuzzy threshold and watershed segmentation of a fuzzy gray weighted distance transformed image.The second level, applied to difficult frames where the first algorithm seems to have failed, is based on a fast geometric active contour model based on the level set algorithm. Finally, the automatic segmentation result on the crucial first frame can be interactively inspected and corrected. Visual inspection and correction can also be applied to other frames but this is generally not needed. For the tracking all cells are classified into inactive, active, dividing and clustered cells. Different algorithms are used to deal with the different cell categories. A special backtracking step is used to automatically correct for some common errors that appear in the initial forward tracking process.

摘要：To make clear the precise hemodynamic mechanism underlying the anti-atherogenesis benefit of enhanced external couterpulsation(EECP) treatment, and to investigate the proper role of some important hemodynamic factors during the atherosclerotic progress, a comprehensive study combining long-term animal experiment and numerical solving was conducted in this paper. An experimentally induced hypercholesterolemic porcine model was developed and the chronic EECP intervention was subjected. Basic hemodynamic measurement was performed in vivo, as well as the arterial endothelial samples were extracted for physiological examination. Meanwhile, a numerical model was introduced to solve the complex hemodynamic factors such as WSS and OSI. The results show that EECP treatment resulted in significant increase of the instant levels of arterial WSS, blood pressure, and OSI. During EECP treatment, the instant OSI level of the common carotid arteries over cardiac cycles raised to a mean value of 8.58 ×10-2 ±2.13 ×10-2. Meanwhile, the chronic intervention of EECP treatment significantly reduced the atherosclerotic lesions in abdominal aortas and the endothelial cellular adherence. The present study suggests that the unique blood flow pattern induced by EECP treatment and the augmentation of WSS level in cardiac cycles may be the most important hemodynamic mechanism that contribute to its anti-atherogenesis effect. And as one of the indices that cause great concern in current hemodynamic study, OSI may not play a key role during the initiation of atherosclerosis.

摘要：Computed tomography (CT) plays an important role in the field of modern medical imaging. Reducing radiation exposure dose without significantly decreasing image's quality is always a crucial issue. Inspired by the outstanding performance of total variation (TV) technique in CT image reconstruction, a TV regularization based Bayesian-MAP (MAP-TV) is proposed to reconstruct the case of sparse view projection and limited angle range imaging. This method can suppress the streak artifacts and geometrical deformation while preserving image edges. We used ordered subset (OS) technique to accelerate the reconstruction speed. Numerical results show that MAP-TV is able to reconstruct a phantom with better visual performance and quantitative evaluation than classical FBP,MLEM and quadrate prior to MAP algorithms. The proposed algorithm can be generalized to cone-beam CT image reconstruction.

摘要：Abstract.Extracting characteristic brain signals and simultaneous recording animals behaving could help us to understand the complex behavior of neuronal ensembles. Here,a system was established to record local field potentials (LFP) and extracellular signal or multiple-unit discharge and behavior synchronously by utilizing electrophysiology and integrated circuit technique. It comprised microelectrodes and micro-driver assembly, analog front end ( AFE), while a computer ( Pentium Ⅲ ) was used as the platform for the graphic user interface, which was developed using the LabVIEW programming language. It was designed as a part of ongoing research to develop a portable wireless neural signal recording system. We believe that this information will be useful for the research of brain-computer interface.

摘要：To investigate the relationship between surface electromyography and subjective assessment of muscle fatigue, 20 young male volunteers participated in the experiment of pistol holding and aiming. sEMG of the anterior deltoid was recorded during the entire process, while fatigue assessments (Borg scale) were collected every 30 s. We divided the signal into several parts and then octave band method was used to calculate mean energy of each part, an equation was derived based on the relationship between the mean energy of sEMG and Borg scale. The results showed that the degree of local muscle fatigue could be described by a cubic curve, and could be used to evaluate and monitor muscle fatigue.

摘要：Objective:To restore cardiac autonomic pace function by autologous transplantation and committed differentiation of bone marrow mesenchymal stem cells, and explore the technique for the treatment of sick sinus syndrome. Methods:Mesenchymal stem cells isolated from canine bone marrow were culture-expanded and differentiated in vitro by 5-azacytidine. The models of sick sinus syndrome in canines were established by ablating sinus node with radio-frequency technique. Differentiated mesenchymal stem cells labeled by BrdU were autologously transplanted into sinus node area through direct injection. The effects of autologous transplantation of mesenchymal stem cells on cardiac autonomic pace function in sick sinus syndrome models were evaluated by electrocardiography, pathologic and immunohistochemical staining technique.Results:There was distinct improvement on pace function of sick sinus syndrome animal models while differentiated mesenchymal stem cells were auto-transplanted into sinus node area. Mesenchymal stem cells transplanted in sinus node area were differentiated into similar sinus node cells and endothelial cells in vivo, and established gap junction with native cardiomyocytes. Conclusion:The committed-induced mesenchymal stem cells transplanted into sinus node area can differentiate into analogous sinus node cells and improve pace function in canine sick sinus syndrome models.

摘要： Objective: This study aims to explore the association between the density of Himalayan marmot (Marmota himalayana) and climatic factors such as temperature, precipitation, humidity, vapour pressure, sunshine percentage, wind velocity, which are closely associated with global climate change, and to provide a reference for plague prevention and control. Methods: We conducted a regression analysis to find the possible climate factors associated with the density of Himalaya marmot, and analyzed the response characters of Himalayan marmot to climate change. Results:Daily precipitation days (>=0.1 mm) and sunshine percentage were significantly associated with the density of Himalayan marmot ( p<0.01). Conclusion:Climate change was associated with the risk of plague. This phenomenon is valuable for Himalayan marmot and plague prevention. More studies are needed to understand the impact of climate change on Himalayan marmot and plague.

摘要：In this paper, we used SVM method to detect P300 signal. Before training a classification parameter for the SVM, several preprocessing operations were applied to the data including filtering, downsampling, single trial extraction, windsorizing, electrode selection et al. With the SVM algorithm, the classification accuracy could be up to above 80%. In some cases, the accuracy could reach 100%. It is suitable to use SVM for P300 EEG recognition in the P300-based brain-computer interface (BCI) system. Our further work will include the improvement to yield higher classification accuracy using fewer trials.

摘要：EEG inverse problem has great significance and importance for both clinical and research applications. It discusses EEG dipole source localization problems solved by nonlinear local optimization methods, such as Levenberg-Marquartb. This paper presents the relation between location errors and noise level on condition that the source number is known; if the source number is not known, the selected number in model may not equal to the actual one, and a computation is carried out and a corresponding discrimination criteria is proposed. Computer simulation demonstrates that Levenberg-Marquardt algorithm is better than global methods if the source number is small.

摘要：Reentrant impulse in the myocardium is considered to be a major factor promoting electrophysiological abnormalities or even leading to ventricular tachycardias (VTs) and ventricular fibrillations (VFs). Tip trajectory of the reentrant wave can reflect stability of the electrical propagation and area of the reentrant movement, thereby being considered as one of the most concerned parameters in studying electrical activities during VT/VF. The purpose of the present study is to propose a practical method to find out tip trajectories using a computational approach. In this study Luo-Rudy 1991 mathematical model of the ventricular cell was used. The operator splitting method was utilized to integrate the partial differential equations in the two-dimensional tissue. And spiral waves were initiated by the cut wave front technique. Through experiments we found it was difficult to find out the tips by finding intersection of the two isovoltage lines as proposed in most papers. Therefore, we suggested that tip points were detected by seeking the shortest distance of the two adjacent isovoltage contour lines. The results showed that tip trajectories of these spiral waves found in our way were very near to the tips observed, implying validation of our method in measuring tip trajectories in cardiac reentry.

摘要： Objective:To investigate the influence of different right ventricular (RV) pacing sites on QRS width, and to provide a potential reference site for permanent right ventricular pacing in patients implanted with permanent pacemakers. Pacing at the site with the shortest QRS duration may reduce the deleterious effects of RV pacing on LV function, and thus having beneficial effects on patient's outcome. Methods: All consecutive patients who were planned to have permanent pacemaker implantation for a Class I or IIa indication at our department from October 2010 to July 2012 were screened for the participation in this prospective, single center, non-randomized study. The baseline surface ECG was analyzed for QRS width and morphology, respectively. During the implantation procedure patients were transiently paced at different RV locations (right ventricular apex, right ventricular inflow tract [RVIT], mid septum, high septum and right ventricular outflow tract [RVOT]) before the lead was placed at its final position. During pacing at the different positions the surface 12-leads ECG was recorded. Based on the surface of ECG QRS duration and morphology of the different right ventricular pacing sites were analyzed and compared with baseline and to each other. Results: A total of 216 patients (39% female, mean age 69 ± 13 years, higher degree AV block 30.5%) was enrolled in the study. Paced QRS duration was significantly different between all right ventricular pacing sites compared with the baseline ECG (baseline:106 ms±21 ms;mean paced:158 ms±16 ms;p<0.001). RVA pacing showed the widest QRS (168 ms±16 ms). QRS duration with RVIT pacing was 166 ms±15 ms, and that with RVOT pacing was 165 ms ± 15 ms, respectively. QRS duration was not significantly different between these three positions. Mid-septal pacing showed the narrowest QRS (139 ms±19 ms) compared to all other pacing sites (p<0.001). Pacing at the high-septum showed a broader QRS (153 ms ± 14 ms) than that pacing at the mid- <br> septum. Compared to other right ventricular pacing sites, QRS morphology at the mid-septum was close to normal, and electrical axis was unchanged as compared to baseline. Conclusion: Pacing at different right ventricular sites showed the significant widening of QRS compared to baseline. The shortest QRS duration was seen with mid-septal pacing. Therefore, mid-septal pacing may have less deleterious effect on LV function compared to other RV pacing locations, which may be the optimal right ventricular pacing site in permanent pacemaker recipients.

摘要：.To meet the needs in the fundus examination, including outlook widening, pathology tracking, etc., this paper describes a robust feature-based method for fully-automatic mosaic of the curved human retinal images photographed by a fundus microscope. The kernel of this new algorithm is the scale-, rotation-and illumination-invariant interest point detector & feature descriptor-Scale-Invariant Feature Transform. When matched interest points according to second-nearest-neighbor strategy, the parameters of the model are estimated using the correct matches of the interest points,extracted by a new inlier identification scheme based on Sampson distance from putative sets. In order to preserve image features, bilinear warping and multi-band blending techniques are used to create panoramic retinal images. Experiments show that the proposed method works well with rejection error in 0.3 pixels, even for those cases where the retinal images without discernable vascular structure in contrast to the state-of-the-art algorithms.

摘要：Objective: Ballistocardiogram (BCG) is a kind of signal that reflects the movement of human body caused by the mechanical activity of cardiovascular system, especially during the heart contraction. Compared to other methods on assessing vascular healthy condition, the acquisition of BCG didn't need any direct contact with human body. This paper uses Hilbert-Huang transformation (HHT) to calculate the heart rate and detect the artifacts. Methods: HHT was a newly-developed method for non-linear data analysis, and ensemble empirical mode decomposition (EEMD) based HHT was a modified HHT method which used white noise to improve the analysis result. A device that could record BCG signal and ECG signal synchronously was built in our lab and 10 subjects' signals were collected and analyzed. EEMD based HHT was applied to BCG signal to calculate the heart rate. Heart rate calculated using ECG was used as a standard value to verify the result calculated from BCG. Besides, BCG was easily affected by the body movement, so we tried to use HHT to detect the artifacts in the BCG signal. Results: Our research showed that EEMD based HHT with a proper white noise level could be used to calculate the heart rate in BCG. Artifacts in the decomposition component were enhanced in the decomposition components of EEMD and became easier to detect than that in original BCG signal. Conclusion: Therefore, HHT could help to calculate the heart rate, enhance and detect artifacts caused by movements of human body in BCG signal.