分类： 生物学 >> 病毒学 分类： 计算机科学 >> 计算机科学技术其他学科 提交时间： 2020-02-21
摘要： 新发传染病爆发流行期间，亟需提出候选药物功效与机制的科学假说。疫苗或新药研发均需要一定时间，因而药物重定位（老药新用）策略有其独特价值。但是新发疾病其病原体、宿主反应的临床数据不充分，制约了候选药物假设的提出。此阶段常根据病人临床特征进行广谱抗病毒药物的尝试。本文借鉴人工智能领域常见的启发式搜索思路，提出一种新方法(aCODE)，基于前期有一定疗效提示的广谱抗病毒药，获得其宿主靶蛋白集合，在全基因组尺度上搜索与之相关性最高的基因模块组合，进而对候选化合物（如已批准上市药物、天然产物）进行模式匹配与统计检验排序。本方法可根据临床实践的进展更新输入药物，迭代输出更精准结果，输出的天然产物或中药、药食同源成分结合其它信息后可实施快速测试，形成敏捷研发测试闭环。本方法的第二版更新及其与文献证据的比对分析请参考：http://chinaxiv.org/abs/202002.00024。
分类： 心理学 >> 认知心理学 提交时间： 2020-02-21
摘要： 针对动作理解的机制，模拟论主张大脑自发模拟他人的动作，就相同的动作其理解也相同，而理论论则认为人们基于合理性原则对他人动作进行推理，相同的动作发生在不同的情境时会有不同的理解。但目前所采用动作材料的运动学特性和发生情境存在共变，其难以区分动作理解是支持模拟论还是理论论。通过两项实验，采用动画制作技术来产生有无约束情境下的追逐动作，以指示动作加工过程的脑电μ抑制为指标，对前述两种观点进行了检验。其中，在约束情境中存在障碍物，追逐者需改变运动方向以绕过障碍物，从后方逐渐趋近目标；而无约束情境中不存在障碍物，但追逐者依然保持与存在约束情景下相同的运动模式。结果发现，当追逐动作发生在存在约束的情境时，其可基于合理性原则推测清晰的动作目标，该条件下的μ抑制程度高于不存在约束情境的条件(实验一)；而当仅追逐者运动，即趋近的目标不确定时，虽然有约束和无约束情境间的物理差异与实验一相同，但条件间μ抑制的差异消失(实验二)。其上述μ抑制并非与注意相关的枕叶α活动的泛化。该结果提示，动作发生的情境信息影响人们对动作的理解，即基于推理过程理解动作，支持理论论观点。
分类： 生物学 >> 病毒学 分类： 生物学 >> 生物进化论 分类： 生物学 >> 遗传学 提交时间： 2020-02-21
摘要： Background. The outbreak of COVID-19 started in mid-December 2019 in Wuhan, Central China. Up to February 18, 2020, SARS-CoV-2 has infected more than 70,000 people in China, and another 25 countries across five continents. In this study, we used 93 complete genomes of SARS-CoV-2 from the GISAID EpiFluTM database to decode the evolution and human-to-human transmissions of SARS-CoV-2 in the recent two months. Methods. Alignment of coding-regions was conducted haplotype analyses using DnaSP. Substitution sites were analyzed in codon. Evolutionary analysis of haplotypes used NETWORK. Population size changes were estimated using both DnaSP and Arlequin. Expansion date of population size was calculated based on the expansion parameter tau (τ) using the formula t=τ/2u. Findings. Eight coding-regions have 120 substitution sites, including 79 non-synonymous and 40 synonymous substitutions. Forty-two non-synonymous substitutions changed the biochemical property of amino acids. No evident combination was found. Fifty-eight haplotypes were classified as five groups, and 31 haplotypes were found in samples from both China and other countries, respectively. The rooted network suggested H13 and H35 to be ancestral haplotypes, and H1 (and its descendent haplotypes including all samples from the Hua Nan market) was derived H3 haplotype. Population size of SARS-CoV-2 were estimated to have a recent expansion on 6 January 2020, and an early expansion on 8 December 2019. Interpretation. Genomic variations of SARS-CoV-2 are still low in comparisons with published genomes of SARS-CoV and MERS-CoV. Phyloepidemiologic analyses indicated the SARS-CoV-2 source at the Hua Nan market should be imported from other places. The crowded market boosted SARS-CoV-2 rapid circulations in the market and spread it to the whole city in early December 2019. Furthermore, phyloepidemiologic approaches have recovered specific direction of human-to-human transmissions, and the import sources of international infectious cases.
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