Bone morphogenetic protein 2/7 promotes repair of bone defect via induction of endochondral ossification

Purpose: To study the influence of bone morphogenetic protein 2/7 (BMP2/7) on repair of bone defect, and the mechanism involved.Methods: Bone marrow stromal cells (BMSCs) were randomly assigned to 2 groups: control and transfection groups. The cells were transfected with rBMP2/7 recombinant adenovirus. Cell growth and alkaline phosphatase (ALP) activity were determined in both groups. Rabbit model of femoral bone defect was prepared using standard methods. Male New Zealand white rabbits were randomly assigned to 3 groups, each of which had 10 rabbits: control, gelatin and BMP2/7 groups. Histopathological and xray examinations, and three-point bending flexural test were used to compare the potential of gelatin and BMP2/7 to repair bone defects.Results: Transfection of BMSCs with rBMP2/7 recombinant adenovirus significantly enhanced their growth (p < 0.05). Alkaline phosphatase (ALP) level was also markedly and time-dependently higher in transfection group than in control group (p < 0.05). Rabbits with grade 4 bone healing or above were more in BMP2/7-treated category than in control and gelatin groups. New bone hyperplasia with typical lamellar bone structure, irregular medullary cavity, as well as transition from osteoblast to osteocyte were observed in BMP2/7 group. Moreover, maximum flexural strength and repair were significantly higher in BMP2/7-transfected group than in control.Conclusion: These findings indicate that BMP2/7 promotes the repair of bone defect via induction of endochondral ossification in rabbits. Thus, this protein may be useful for the repair of bone defects in humans. Keywords: Alkaline phosphatase, Bone lesions, BMP2/7, Endochondral ossificatio

A Spectral Diffusion Prior for Hyperspectral Image Super-Resolution

Fusion-based hyperspectral image (HSI) super-resolution aims to produce a high-spatial-resolution HSI by fusing a low-spatial-resolution HSI and a high-spatial-resolution multispectral image. Such a HSI super-resolution process can be modeled as an inverse problem, where the prior knowledge is essential for obtaining the desired solution. Motivated by the success of diffusion models, we propose a novel spectral diffusion prior for fusion-based HSI super-resolution. Specifically, we first investigate the spectrum generation problem and design a spectral diffusion model to model the spectral data distribution. Then, in the framework of maximum a posteriori, we keep the transition information between every two neighboring states during the reverse generative process, and thereby embed the knowledge of trained spectral diffusion model into the fusion problem in the form of a regularization term. At last, we treat each generation step of the final optimization problem as its subproblem, and employ the Adam to solve these subproblems in a reverse sequence. Experimental results conducted on both synthetic and real datasets demonstrate the effectiveness of the proposed approach. The code of the proposed approach will be available on https://github.com/liuofficial/SDP

An experiment and simulation study of the rebound effect in electromagnetic forming process

Electromagnetic forming (EMF) has been proved to be a useful method to form the aluminium alloy sheet as it has so many advantages. As a high-speed forming process, it can suppress crack, reduce springback, and improve the formability of material at room temperature. But in the process of EMF, the rebound effect caused by high velocity impact has an important effect on the flatness of the formed part. Then a spring damper system has been added under the female stop block to eliminate this effect. The results of formed shape, thickness distribution and stress and strain state are investigated by comparing with free-forming process. On the other hand, the influence of spring stiffness and damping coefficient is analysed by using of ANSYS loose-coupled method. The results shows that it helps to improve the flatness of formed parts with a spring damper system used. Beside of the changing of formed shape, the difference of stress strain state results in difference of thickness distribution. And crack happened at the bottom is supressed, and this does favour for further processing. Furthermore, the results also shows that low spring stiffness and right damping coefficient are benefit for reducing the rebound effect

On-line detection method for outliers of dynamic instability measurement data in geological exploration control process

Considering the characteristics of the vibration data detected by the unstable regulation process in the grinding and grading control system and the shortcomings of the traditional wavelet anomaly detection method, an online anomaly detection method combining autoregressive and wavelet analysis is proposed. By introducing the improved robust AR model, this method can overcome the problem that the time and frequency of traditional anomaly detection using wavelet analysis method cannot be well balanced and ensure the rationality of normal detection of process data. Considering the characteristics of parameter change and dynamic characteristics in the process of grinding and grading, the proposed method has the ability of on-line detection and parameter updating in real time, which ensures the control parameters of time-varying process control system. In order to avoid the problem that the traditional anomaly detection method needs to set the detection threshold, introduce the HMM to analyse the wavelet coefficients and update the HMM parameters online, which can ensure that the HMM can well reflect the distribution of the abnormal value of the process data. Through the experiment and application, it is proven that the anomaly data detection method proposed in this paper is more suitable for the detection data in the process of unstable regulation