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31.
The development and maturation of an oligodendroglial cell is comprised of three intimately related processes that include proliferation, differentiation, and myelination. Here we review how proliferation and differentiation are controlled by distinct molecular mechanisms and discuss whether differentiation is merely a default of inhibited proliferation. We then address whether differentiation and myelination can be uncoupled in a similar manner. This task is particularly challenging because an oligodendrocyte cannot myelinate without first differentiating, and these processes are therefore not mutually exclusive. Is it solely the presence of the axon that distinguishes a differentiated oligodendrocyte from a myelinating one? Uncoupling these two processes requires identifying specific signals that regulate myelination without affecting the differentiation process. We will review current understanding of the relationship between differentiation and myelination and discuss whether these two processes can truly be uncoupled. 相似文献
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自动识别和描述图像的内容是人工智能中一个重要的研究方向,它涉及计算机视觉和自然语言处理技术。针对这一难题,提出了一种由深层神经网络模型生成自然语言句子来描述图像内容的方法。该方法提出的模型由卷积神经网络(Convolution Neural Network,CNN)和循环神经网络(Recurrent Neural Network,RNN)组成,其中,CNN用来提取输入图像的特征生成固定长度的特征向量,该特征向量初始化RNN来生成句子。在MSCOCO图像描述数据集上的实验结果表明了该模型所生成句子的语法准确性和语义准确性,且优于先前的基线模型。 相似文献
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Lin Z Bei JX Shen M Li Q Liao Z Zhang Y Lv Q Wei Q Low HQ Guo YM Cao S Yang M Hu Z Xu M Wang X Wei Y Li L Li C Li T Huang J Pan Y Jin O Wu Y Wu J Guo Z He P Hu S Wu H Song H Zhan F Liu S Gao G Liu Z Li Y Xiao C Li J Ye Z He W Liu D Shen L Huang A Wu H Tao Y Pan X Yu B Tai ES Zeng YX Ren EC Shen Y Liu J Gu J 《Nature genetics》2012,44(1):73-77
To identify susceptibility loci for ankylosing spondylitis, we performed a two-stage genome-wide association study in Han Chinese. In the discovery stage, we analyzed 1,356,350 autosomal SNPs in 1,837 individuals with ankylosing spondylitis and 4,231 controls; in the validation stage, we analyzed 30 suggestive SNPs in an additional 2,100 affected individuals and 3,496 controls. We identified two new susceptibility loci between EDIL3 and HAPLN1 at 5q14.3 (rs4552569; P = 8.77 × 10(-10)) and within ANO6 at 12q12 (rs17095830; P = 1.63 × 10(-8)). We also confirmed previously reported associations in Europeans within the major histocompatibility complex (MHC) region (top SNP, rs13202464; P < 5 × 10(-324)) and at 2p15 (rs10865331; P = 1.98 × 10(-8)). We show that rs13202464 within the MHC region mainly represents the risk effect of HLA-B*27 variants (including HLA-B*2704, HLA-B*2705 and HLA-B*2715) in Chinese. The two newly discovered loci implicate genes related to bone formation and cartilage development, suggesting their potential involvement in the etiology of ankylosing spondylitis. 相似文献
35.
Enucleated oocytes have the distinctive ability to reprogram somatic nuclei back to totipotency. Here, we investigate genome-scale DNA methylation patterns after nuclear transfer and compare them to the dynamics at fertilization. We identify specific targets for DNA demethylation after nuclear transfer, such as germline-associated promoters, as well as unique limitations that include certain repetitive element classes. 相似文献
36.
A rare penetrant mutation in CFH confers high risk of age-related macular degeneration 总被引:1,自引:0,他引:1
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Yun Liu Zeyao Zhu Idy H. T. Ho Yujian Shi Yuxin Xie Jianzhen Li Yong Zhang Matthew T. V. Chan Christopher H. K. Cheng 《Cellular and molecular life sciences : CMLS》2017,74(13):2503-2511
Zebrafish is an important model to study developmental biology and human diseases. However, an effective approach to achieve spatial and temporal gene knockout in zebrafish has not been well established. In this study, we have developed a new approach, namely bacterial artificial chromosome-rescue-based knockout (BACK), to achieve conditional gene knockout in zebrafish using the Cre/loxP system. We have successfully deleted the DiGeorge syndrome critical region gene 8 (dgcr8) in zebrafish germ line and demonstrated that the maternal-zygotic dgcr8 (MZdgcr8) embryos exhibit MZdicer-like phenotypes with morphological defects which could be rescued by miR-430, indicating that canonical microRNAs play critical role in early development. Our findings establish that Cre/loxP-mediated tissue-specific gene knockout could be achieved using this BACK strategy and that canonical microRNAs play important roles in early embryonic development in zebrafish. 相似文献
39.
Using an analogy in science and everyday life is a double-edged sword because they are accompanied by alternative ideas, in addition to scientific concepts. Schools and public education explain global warming by making a common analogy between this phenomenon and greenhouse effects (Chen in Philos Cogn Sci 105–114, 2012). Unfortunately, this analogy sometimes produces various incorrect explanatory mental models. To construct a correct understanding of global warming, it is necessary: first, to investigate the attributes of analogical reasoning; second, to understand these features by restructuring the greenhouse analogy; and third, to explore the problems and benefits of the greenhouse analogy. The characteristics of relations, rather than objects, must be mapped according to the principle of systematicity, but the public tends to preserve the attributes of the base domain, which is mapped relatively easily. In conclusion, certain facets of the prevailing greenhouse analogy cause a distorted public view of climate change. We must use the greenhouse analogy and yet simultaneously emphasize the relations and attributes highlighted and hidden in the analogy during evaluation. 相似文献
40.
Six new loci associated with blood low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglycerides in humans 总被引:2,自引:0,他引:2
Kathiresan S Melander O Guiducci C Surti A Burtt NP Rieder MJ Cooper GM Roos C Voight BF Havulinna AS Wahlstrand B Hedner T Corella D Tai ES Ordovas JM Berglund G Vartiainen E Jousilahti P Hedblad B Taskinen MR Newton-Cheh C Salomaa V Peltonen L Groop L Altshuler DM Orho-Melander M 《Nature genetics》2008,40(2):189-197