2017, 6(2):1-10. DOI: 10.12146/j.issn.2095-3135.201702001
Abstract:Hypnosis is an effective psychological technology in respiratory motion control. In this study, functional magnetic imaging was applied to an intra-subject (n＝13) design hypnosis experiment guided by hypnotists to analyze the respiratory motion control and neural activity in hypnosis. As a result, increased brain activities were observed in visual cortex, sensorimotor cortex, posterior cingulate cortex and middle temporal gyrus, and decreased in dorsolateral prefrontal cortex, cerebellum posterior lobe and supramarginal gyrus. Moreover, compared with normal state, enhanced correlation of brain activities (normal state, r＝0.64; hypnosis state, r＝0.80) was observed within large-scale resting-state networks. Increased connectivity between sensorimotor cortex and visual cortex in hypnosis was also observed, which implies their critical roles in neural mechanisms of hypnosis for respiration control and involvement of cognitive and perceptual processing therein. This study provides new insights for hypnosis study in psychology and cognitive neuroscience.
2017, 6(2):11-21. DOI: 10.12146/j.issn.2095-3135.201702002
Abstract:Greenhouse mapping has attracted much attention recently, especially in China where greenhouse practice has been growing dramatically. Remote sensing based greenhouse extraction methods can generate the geographical locations and spatial distribution of greenhouses efficiently. Most of the existing greenhouse extraction algorithms rely on high-resolution remote sensing images or aerial images, which are often expensive to obtain and require complicated algorithms to process. To solve this problem, this paper proposes a fast algorithm for greenhouse extraction based on Landsat images that are freely available. First, an enhanced water index was introduced to characterize winter greenhouse, based on an observed natural phenomenon that water vapor inside a greenhouse is usually condensed to form a layer of dew on the inner surface of the greenhouse plastic or glass. On one hand, the dew layer makes a greenhouse has a high water index value, which makes it to be distinguished easily from bare land. On the other hand, the dew layer increases a greenhouse’s reflectivity, which makes it different from natural water bodies. In order to extract greenhouses, a simple and efficient decision tree classifier was designed. Da’ao town of Jiangmen in Guangdong Province was chosen as an example, and the experiments were based on Landsat images taken in different years. The results show that the proposed method is effective in extracting greenhouses, with the advantages of high efficiency, low cost, and strong robustness.
2017, 6(2):22-31. DOI: 10.12146/j.issn.2095-3135.201702003
Abstract:X-ray shading artifacts lead to CT number inaccuracy, image contrast loss and spatial nonuniformity, and therefore are considered as one of the fundamental limitations of cone-beam CT(CBCT). In order to solve this problem, a novel shading correction method was proposed. First, a multi-threshold segmentation algorithm was used to segment the original CT image for constructing a template image where each structure is filled with the same CT number of a specific tissue type. Then, the L0 norm smoothing algorithm was used to smooth the CBCT image for constructing an image without texture. By subtracting the template from the image without texture, the residual images from various error sources were low-pass filtered to generate the estimated shading artifacts. Finally, the estimated shading artifacts were added back to the original image for shading correction. Compared with the CT image without correction, the proposed method reduced the overall CT number error from over 115 HU to be less than 13 HU and decreased the nonuniformity from over 9% to be less than 1%. The experimental results demonstrate that the proposed shading correction method using L0 norm smoothing and image segmentation can effectively correct the shading artifacts and its feasibility in clinical application is validated.
2017, 6(2):32-40. DOI: 10.12146/j.issn.2095-3135.201702004
Abstract:To study the effect of dihydrotestosterone on the osteogenic differentiation of bone marrow mesenchymal stem cells after chemokine-like receptor 1 (CMKLR1) gene knockout, dihydrotestosterone and N,N,N-trimethyl-γ-oxo-2-naphthalenepropanaminium, monoiodide were injected in mice and induced bone marrow mesenchymal stem cells in vitro. The results showed that osteogenic differentiation rate decreased after CMKLR1 gene knockout and increased when dihydrotestosterone was injected in wild type mice bone marrow mesenchymal stem cells. However, there was no significant change in CMKLR1 knockout mice. The result indicated that the effect of dihydrotestosterone on bone cells was affected by the deletion of CMKLR1.
2017, 6(2):41-48. DOI: 10.12146/j.issn.2095-3135.201702005
Abstract:Medical imaging is a complicated procedure and acquired images are with intrinsic characteristics. As a tool to quantify the image quality, signal-to-noise ratio (SNR) is widely accepted by physicians in clinical situations. It is defined as the quotient of the mean signal intensity in a tissue region of interest and the standard deviation of the signal intensity in a region outside the anatomy of the object imaged. However, insufficient knowledge on its consistency with respect to different observers and tissue regions is known. In this paper, the consistency is studied with 324 simulated MR images of human brain. The consistency of SNR is validated between two observers and between tissues of white matter and cerebral spinal fluid. For the same type of tissues in each modality, Wilcoxon rank sum test suggests no significant difference between two observers(P＞0.70). For the same modality and observer, SNR between tissues correlates well (Pearson correlation coefficient rp＞0.71(P＜10－5), and Spearman’s rank correlation coefficient rs＞0.97(P＜10－3). This study indicates that SNR is consistent and robust regarding to different observers and tissues in objective quality assessment of magnetic resonance images. Further research will be carried on clinical images for objective assessment.
2017, 6(2):49-58. DOI: 10.12146/j.issn.2095-3135.201702006
Abstract:Aurora kinase is a family of serine/threonine protein kinases and plays essential roles in cell proliferation. The human Aurora kinase family has three members: Aurora A, Aurora B and Aurora C. Aurora family kinase has critical roles in mitotic progression. Aberrant expression of Aurora kinase causes abnormal mitotic progression and thereby leads to genetic instability and carcinogenesis. Aurora kinase is frequently over-expressed in many types of human tumors and contributes to the tumors development. Thus, development of inhibitors targeting Aurora family kinase provides new strategies for cancer treatment. To date, a considerable number of Aurora family kinase inhibitors have been developed, among which, great antitumor effects were shown in some inhibitors and progressed into clinical studies.
2017, 6(2):59-65. DOI: 10.12146/j.issn.2095-3135.201702007
Abstract:Establishment of safe and effective gene vectors and in vivo delivery systems are crucial for gene therapy. The vectors for gene therapy comprise viral and non-viral vectors. Of which the viral vectors have been widely applied in clinical trials, due to their highly transduction efficiency; while they still encounter many potential safety concerns. In contrast, the non-viral vectors are safe and easy to prepare gene vehicles. However, the insufficient transfection efficiency limits their clinical application. Many efforts have been devoted into optimizing the delivery systems to enhance the gene transfer efficiency of non-viral vectors, a few of which are currently undergoing clinical trials. In this review, the recent advances of non-viral gene delivery systems and their clinical prospects were summarized.
2017, 6(2):66-72. DOI: 10.12146/j.issn.2095-3135.201702008
Abstract:Limited to the system architecture in conventional CT, artifacts induced by respiratory motion during routine diagnosis severely degrades the image quality. A novel micro-CT system performing well in a quasi-static way is proposed according to the principle of field emission. It employs 35 carbon nanotubes based X-ray tubes and 5 flat detectors, motion artifacts can be greatly suppressed by reducing the gantry rotation times and range under control of external sequential when compared with conventional CT system. To validate the feasibility of the proposed system, iterative reconstruction algorithm is adopted on simulation due to sparse sampling.
2017, 6(2):73-80. DOI: 10.12146/j.issn.2095-3135.201702009
Abstract:With the development of computer graphics, the models applied to agmented reality(AR) /virtual reality (VR) tend to be more complicated. Highly detailed representation without reducing frame rate either requires powerful computing devices or models with low complexity. The latter one is usually a more practical choice. Reducing the fineness of model to protect the AR/VR in real-time becomes a challenge. In this paper, a new method based on greedy assignment and Laplacian smoothing algorithm was introduced. Experimental results demonstrate that the proposed method has the least distortion under the same ratio of simplification, and can better meet the real-time requirements of AR/VR.