Collagen/bioactive glass/chitosan composite scaffolds / 中国组织工程研究

BACKGROUND:Col agen/bioactive glass composite materials possess excellent osteogenic potential and biocompatibility, but its application in bone tissue engineering is limited by mechanical property and degradation. OBJECTIVE:To construct col agen/bioactive glass/chitosan composite scaffolds with good mechanical property, anti-degradation ability and bone repair property. METHODS:Bioactive glass/col agen composite scaffolds with chitosan as dispersant were prepared by lyophylization. Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, and dynamic biomechanical testing were used to characterize the structure and properties of the composite scaffolds. RESULTS AND CONCLUSION:Results show that charge-attractions in pre-prepared bioactive glass/chitosan solution increased the homogeneity of bioactive glass dispersed in col agen gel and the compressive modulus and strength increased significantly due to the homogeneity and intermolecular interactions between chitosan and col agen. The enzymatic degradation rate and mineralization activity in the simulated body fluid were also lower because of a high degree of embedment of bioactive glass in col agen/chitosan matrix, and entanglement of col agen in chitosan at molecular level, which decreased the exposure of bioactive glass to the simulated body fluid, and col agen to enzyme solution.

Combined middle meatus and expand pre-lacrimal recess-maxillary sinus approach for endoscopic maxillary sinus surgery / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study surgical techniques and clinical applications of the intranasal endoscopic combined approach in maxillary sinus benign lesions surgery.@*METHOD@#A retrospective clinical analysis of 27 patients "whose unilateral maxillary sinus benign lesions operated by the intranasal endoscopic middle meatus with inferior meatus tears recess approach surgical treatment was studied.@*RESULT@#Benign lesions were confirmed by pathology in all patients before and after surgery as to rule out malignancy. All patients had been followed up for 12 to 24 months. Twenty-seven cases resulted in normal luminal epithelium and inferior turbinate shape after surgery. Only one case of papilloma relapsed 2 months after operation. So far, the papilloma has not recurred after the second surgery. There were no epiphora in all cases.@*CONCLUSION@#Endonasal endoscopic expand anterior tears recess approach have great and clear view. This approach made us accurately, mini-invade and completely remove the maxillary sinus benign lesions. It is a physiological and functional surgery and has great advantage in the nasal cavity disease treatment.

Investigation on Mechanical Property of the Compound Scaffold of Sol-Gel Bioactive Glass/Collegan / 医用生物力学

Objective To investigate the mechanical prosperity and degradation rate of the scaffolds by compounding collagen and the nano sol-gel derived bioactive glass were studied in this paper，and that would provide the theoretical basis for the further application of collagen based scaffold. Method The scaffold by compounding collagen and the nano sol-gel derived bioactive glass (58S) were prepared using the freeze-drying techniques with the bioactive glass as phase addition. To affect the aggregation state of the collagen fibers with adjusting the supplementation of bioactive glass, then the microstructures of the compound scaffold would be different. At last, the compound scaffolds with different mechanical properties were prepared. Results (1) As the aggregation state of the collagen fibers changed, the scaffold with the coarser collagen fibers with the diameters 400-600nm approximately is prepared. The coarser collagen fibers would play an important role in improving the mechanical property and slowing down the degradation rate of the collagen based scaffolds. (2) The interactions between bioactive glass and collagen are studied by FTIR and Raman technologies. When the quality of content of collagen in the compound scaffold is lower than 20%, the secondary structure of collagen is damaged severely. Conclusions The composite scaffold with the mass ratio of collagen to bioactive glass to 40:60 has the best performance in mechanical property and degradation, which would be helpful for further applications

Investigation on mechanical property of the compound scaffold of Sol-Gel bioactive glass/collegan / 医用生物力学

Objective To investigate the mechanical prosperity and degradation rate of the scaffolds with compounding collagen and the nano sol-gel derived bioactive glass were studied,and provide the theoretical basis for the further application of collagen based scaffolds.Method The scaffold with compounding collagen and the nano sol-gel derived bioactive glass(58S)were prepared using the freeze-drying techniques with the bioactive glass as phase addition.By affecting the aggregation state of the collagen fibers with adjusting the supplementation of bioactive glass to change the microstructures of the compound scaffolds and finatly the compound scaffolds with different mechanical properties were prepared.Results (1)As the aggregation state of the collagen fibers changes,the scaffolds with the coarser collagen fibers is prepared with the diameters 400-600 nm approximately.The coarser collagen fibers will play an important role in improving the mechanical property and slowing down the degradation rate of the collagen based scaffolds.(2)The interactions between bioactive glass and collagen are studied by FTIR and Raman technologies.When the quality of content of collagen in the compound scaffolds is lower than 20%,the secondary structure of collagen is damaged severely.Conclusion The composite scaffolds with the mass ratio of collagen to bioactive glass 40:60 has the best performance in mechanical property and degradation,which will be helpful for further applications.

An improved morphological edge detection algorithm of medical image based on multi-structure element / 生物医学工程学杂志

An improved edge detection algorithm is proposed in this paper for the medical images with strong noises and fuzzy edges. The algorithm modified the combination of morphological operations, so that the unclear edges of the images are avoided. In this paper is also introduced the algorithm of multi-structure elements which can reserve integrated edges from different directions of the images. Furthermore, the contrast enhancement and morphological filter processing are implemented. This method can detect the edges efficiently, keep the detected edges smooth and obtain coherent image edges. Experiments demonstrate that this edge detector has a better performance of noise reduction and keeps the edges more accurate than do the traditional edge detectors; thus its practicality is enhanced.

A modified fast independent component analysis and its application to ERP extraction / 生物医学工程学杂志

Feature extraction of event-related potentials (ERP) plays an important part in both basic and clinical researches for cerebral neurophysiology. ICA is a method for separating blind signals based on signal statistic characteristics. In this paper, the fundamental principle, the discrimination condition and the practical algorithm of Independent Component Analysis are discussed. Then, a fast Independent Component Analysis algorithm (Fast ICA) is introduced. But like Fast ICA, its convergence is dependent on initial weight. We bring in a revision factor into the algorithm; thus the new algorithm could implement convergence on a largescale. In this paper, the revision factor is calculated by gradient. By modifying kernel iterate course, several iterations of Fast ICA are merged into one iteration of Modified Fast ICA, so the convergence of ICA will be accelerated. Finally, Modified ICA is applied to ERP extraction. The simulation shows that the convergence speed can be increased by using the improved algorithm.

A study of ECG combination detection algorithm based on wavelet transform and morphological method / 生物医学工程学杂志

In order to deal with the disadvantages in ECG waveform detection by wavelet harr transform at level 3, we put forward a new set of algorithm which combines wavelet transform (WT) and morphological peak and valley detection. The combination algorithm can make up the limitation in detecting ECG swing by WT and improve the accuracy of ECG waveform detection effectively.

Experimental research of intraocular retention of domestic perfluorocarbon liquid / 中华眼底病杂志

Objective To investigate the effect of long-term intraocular retention of domestic perfluorocarbon liquid (PFCL) on morphology and histology of ocular tissues. Methods A total of 18 New-Zealand rabbits were randomly divided into 3 experimental groups, whose left eyes underwent intraocular injection with 0.3, 0.6, and 1.0 ml PFCL, respectively. All of the right eyes of the rabbits were in the control group. The morphological, electrophysiological and histological changes of the ocular tissue were observed 4, 8, and 12 weeks after the injection. Results No clinically significant retinopathy but only mild morphological changes were found in group 1 and 2, while obvious morphological and histological changes were found in group 3. Mild morphological and histological changes were found in all of the rabbits 4-8 weeks after the injection while significant ones were found 8-12 weeks after the injection. The results of electroretinography indicated a statistically significant decline of amplitude of b wave in group 3. Conclusions Long-term intraocular retention of few PFCL may cause mild histological changes but not affect the clinical function. Plentiful PFCL remains in eyes may lead to toxic reaction to the ocular tissue.