Objective To examine the segmental bone defects healing by ? TCP/rhBMP 2 composites with different degradation rate and discuss the relationship between osteogenesis and degradation of ? TCP in vivo. Methods Three kinds of ? tricalcium phosphate(? TCP) with different degradation rate (? TCP1-3) were prepared by means of different techniques. ? TCP/rhBMP 2 composites with different degradation rate(? TCP1/rhBMP 2 and ? TCP2/rhBMP 2)were obtained by combining ? TCP1, ? TCP2 with recombinant human bone morphogenetic protein 2(rhBMP 2), respectively. ? TCP1/rhBMP 2, ? TCP2/rhBMP 2, ? TCP1, ? TCP2 and ? TCP3 were used to repair 15 mm radial segmental defects in 81 Chinese rabbits. When the samples were harvested in 4, 8, 16 and 24 weeks after surgery, a series of examination were carried out, including the roentgenographical, histomorphological, biomechanical and computerized graphical analysis, energy dispersion analysis X ray (EDAX), and measurements of inorganic contents. Results Roentgenographically and histologically, all of the defects that had been treated with implants exhibited new bone formation, increasing with time. The quantity and rate of new bone formation in ? TCP1/rhBMP 2 group and ? TCP2/rhBMP 2 group were higher than those in group of ? TCP alone. The ability of new bone formation in ? TCP1/rhBMP 2 group was strongest. At 24 weeks the defects in ? TCP1/rhBMP 2 group were bridged with the appearance of marrow cavities, the inorganic contents and ratio of calcium to phosphate and biomechanical property in implants approached to those of normal bone. Although degradation occurred to some extent in ? TCP alone the degradation were faster in ? TCP/rhBMP 2 composites. At 24 weeks the degradation rate in ? TCP1/rhBMP 2 group and ? TCP2/rhBMP 2 group were 97.4%and 73.4%, respectively. The defects in blank controls were repaired only by fibrous tissue at 24 weeks. Conclusion ? TCP/rhBMP 2 composites with different degradation rate could repair segmental bone defects, and osteogenesis could accelerate the degradation of ? TCP in vivo.

The methods, present research situation, existing problems, and application foreground of multidimensional reconstruction of ultras onic heart images are discussed in the present paper. According to the procedure of multidimensional reconstruction of ultrasonic heart images, the discussions are presented in respect toimage acquisition, processing, and display. Based on the present situation and existing problems, the future development and applica tion foreground are proposed.

Several kinds of filters for medical ultrasonic images, suchas multidimensional filter, adaptive weighted filter (for example, adaptive weighted median filter), adaptive window selecting filter (for example , homogeneous region growing mean filter and adaptive speckle suppression filter ) and two-step filter, are introduced. The existing problems and the progress trend are also discussed. Some application instances for medical ultrasonic images of the filters discussed and the performance of the filters presented are based on the present authors' practice.

Contour detection is one of the most difficult problems in the multi-dimensional reconstruction of echocardiographic images. A method based on active contour model is presented in the present paper to solve this problem. First, according to the characteristic of the ultrasonic medical images, an adaptive weighted median filter is used to suppress speckle noise and an adaptive threshold value is selected to get binary image. Then, mathematical morphological treatment is utilized to get the initial contour. At last, active contour model is employed to revise the initial contour and get the accurate final contour. Experiments with real and interpolated ultrasonic images are presented. The results show the effectiveness of this method. This method has practical use in the multi-dimensional reconstruction of ultrasonic medical images.

During the preparation of functional gradient materials (FGM) with plasma immersion ion implantation-ion beam enhanced deposition (PIII-IBED), the combination strength between the coating and the substrate would be greatly affected by the implantation dose and the distribution of implanted ions in substrate. According to the requirements of FGM, an idea of multi grades energy implantation had been suggested, with which the Gauss peak could be moved toward the surface, and the concentration of implanted ions could be maximized at the surface. In this study, the distribution of carbon ions implanted into titanic alloy substrate have been simulated theoretically, and the tentative idea have been confirmed experimentally.
Alloys ; Carbon ; Coated Materials, Biocompatible ; chemical synthesis ; Computer Simulation ; Heart Valve Prosthesis ; Titanium

Studies on bioactive glass and glass-ceramic are important research high-lights in the field of biomedical materials. Due to their bioactivity, these materials can form a tight chemical bond with the living bone, when implanted. As a preeminent kind of these materials, A-W(Apatite/Wollastonite) bioactive glass ceramic has not only the excellent bioactivity and biocompatibility, but also the eminent mechanical properties, so it has been largely applied and developed in clinical practice. The development, preparation, properties, applications and the mechanism of its bond with bone are introduced in this paper. We will also put forward the prospect of the research and development of A-W bioactive glass ceramic.
Apatites ; chemistry ; Bone Substitutes ; chemistry ; Calcium Compounds ; chemistry ; Ceramics ; chemistry ; Mechanics ; Research ; Silicates ; chemistry ; Surface Properties

Objective To improve the precision of the traditional segmentation of echocardiogram, by suppressing the influence from inherent speckle noises in medical ultrasonic images. Method An automatic segmentation method based on reconstructed morphology was proposed in this paper. First, the opening and closing operations by reconstruction were imposed to the ultrasonic image. Second, the top-hat operation was used to extract the bright and/or dark features and to find out the boundaries corresponding to these features, whereby implemented the automatic segmentation. Result The segmented echocardiogram had less artificial boundaries resulted from speckle noise, and could accurately be extracted the artery and ventricle. Conclusion The presented method can detect both dark and bright objects accurately, and the boundary has a fine continuity. In addition, the algorithm is also applicable to the extraction of sole bright/dark features, accordingly to reduce the complexity and time needed and to improve the accuracy.

A promising alternative to supply bone substitutes is to develop living tissue substitutes based on biodegradable materials, which is called bone tissue engineering. One of the research high-lights of bone tissue engineering is to design and manufacture scaffolds for cell attaching, migrating, and proliferating. A process which consists of a solvent casting stage, a compression molding stage and a leaching stage has been used to fabricate macroporous composites of poly(l-lactic acid)(PLLA) and β-tricalcium phosphate (β-TCP). The effects of the weight fraction of porogen-NaCl, of the weight ratio of PLLA to β-TCP and of the diameters of β-TCP on the porosities, the average pore diameters and the compressive yield strength and compressive modulus have been studied. The results showed that the porosities and the average pore diameters increased and the compressive yield strength and modulus decreased when the weight fraction went from 50% to 90%. The compressive yield strength and compressive modulus could be improved by changing the weight ratio of PLLA to β-TCP and the diameters of β-TCP in low-porosity composites (lower than 70%). But high-porosity composites (90%) were not reinforced by changing the weight ratio.

In the present paper, adhesive test, morphology observation, classified counting and deformation index calculation of the platelets on seven DLC samples made by different processes were carried out after XPS analysis, respectively. Then the effects of carbon phase components on amounts and deformation index of the platelets adhered to the samples were investigated by using the analysis of T-type correlation degree in the grey system theory. It has been shown from results that the amounts and the deformation index of the platelets adhered to the DLC samples made by plasma source ion implantation-ion beam enhanced deposition (PSII-IBED) are obviously less than those of DLC samples made by plasma CVD. The correlation degrees (negative) between the DLC carbon phase and the amounts as well as the deformation index of platelets are much more than those of the other four carbon phase components; besides, larger correlation degrees (positive) only appear between the deformation index of platelets and the C-H carbon phase or C-O carbon phase. It has been indicated that: (1) the effect of DLC carbon phase on platelets adhesion is much greater than that of the other four carbon phase components, the key to improvement in the hemocompatibility of DLC is to increase the DLC carbon phase content; (2) it is necessary to restrain the form or decrease the C-H carbon phase content and C-O carbon phase content so as to control their promotive action on deformation of the platelets adhered to the surface of DLC; (3) using PSII-IBED process to prepare DLC is helpful to improving the hemocompatibility of DLC. These conclusions are essential for designing and improving the deposition process of DLC.
Biocompatible Materials ; Carbon ; chemistry ; Diamond ; chemistry ; Humans ; Male ; Materials Testing ; Models, Biological ; Platelet Adhesiveness

In the present paper, the influence of carbon phase components of three kinds of diamond like carbon (DLC) films, viz. DLC, DLC rich in graphite and DLC rich in diamond films, on adsorption of human serum albumin (HSA), human serum fibrinogen (HFG) and immunoglobin (IgG) was quantitatively analyzed by use of T-type correlation degree in the grey system theory. Through the analysis, the rational explanation for adsorptive amounts variations of the serum proteins with phase components in the experiment is reached and some essential conclusions have been obtained: (1) The effect of graphite phase and C-H phase on HSA adsorption are greater than that of other phase components; with the increase of these two phase coumponents, the adsorptive amounts of HSA decrease; (2) The powerful influence on HFG adsorption stems from DLC phase and C-O phase; with the decrease of DLC phase or the increase of C-O phase, the adsorptive amounts of HFG increase; (3) All of the carbon phase components have only limited influence on IgG adsorption in positive or negative fashion with a little difference in degree; (4) DLC phase has both effects of enhancing adsorption for HSA and weakening adsorption for HFG and IgG, thus its influence on the hemocompatibility of DLC films is much more important than that of other phase components.
Adsorption ; Carbon ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Diamond ; chemistry ; Humans ; Materials Testing ; Membranes, Artificial ; Serum Albumin ; chemistry ; Surface Properties