知识追踪旨在评估学习者的学习状态,并根据先前的答题情况预测他们未来的答题表现.然而现有的知识追踪模型大多仅关注问题或技能间的关联,忽略了学生与问题间的结构关系.为此我们提出了基于学生问题关联的异构图知识追踪模型(StudentPro...知识追踪旨在评估学习者的学习状态,并根据先前的答题情况预测他们未来的答题表现.然而现有的知识追踪模型大多仅关注问题或技能间的关联,忽略了学生与问题间的结构关系.为此我们提出了基于学生问题关联的异构图知识追踪模型(StudentProblem association based heterogeneous graph Knowledge Tracing model,SPKT).该模型在知识追踪中融合了学生的学习能力和问题的重要性,并使用图注意力网络学习学生问题间的关联,获得学生、问题的嵌入表示并进行知识状态的预测.通过在真实公开数据集上的性能对比和模型消融实验,并可视化SPKT模型的知识追踪效果,证明了SPKT在预测性能上优于现有的知识追踪模型.展开更多
During the development of mammalian heart, the left and right atria play an important role in cardiovascular circulation. The embryonic atrium is mainly formed by the differentiation of progenitor cells and the prolif...During the development of mammalian heart, the left and right atria play an important role in cardiovascular circulation. The embryonic atrium is mainly formed by the differentiation of progenitor cells and the proliferation of cardiomyocytes, while the postnatal atrium is primarily shaped by the increase in the volume of cardiomyocytes. Cell proliferation and differentiation of atrial development is the basis for its functions such as “blood reservoir” and “supplementary pump”. Deep understanding the cellular mechanism of atrial development is imperative to explore the causes of common congenital arrhythmia heart diseases such as atrial fibrillation. We used genetically engineered mouse reproduction knowledge, lineage tracing method based on CreloxP system, molecular biology and immunofluorescence technology to track the cardiomyocyte lineage of Nppa-GFP mouse line with stereo fluorescence microscope and ultra-high-speed confocal microscope. Besides the atrium of Nppa-CreER;Rosa26 tdTomato mouse was examined during embryonic (E10.5 - E18.5) and postnatal (P0, P3, P5, P7, P14, P28, P8w) stage. Immunofluorescence results revealed that Nppa-positive cells labeled TNNI3-positive cardiomyocytes and protruded into the atrial cavity at the beginning of E11.5 - E12.0 and during subsequent development to form Nppa-positive myocardial trabeculae. Thick comb-shaped myocardium was observed after birth, and we suspect that this was particularly important for the normal contractile activity and pumping function of the atrium. Additionally, non-single origin of Nppa-positive trabecular myocardiocytes were revealed through Tamoxifen-induced lineage tracing experiment. Our findings reveal proliferation dynamics and non-comprehensive fate decisions of cardiomyocytes that produce the distinct architecture of the atrium chamber.展开更多
COVID-19 has spread globally to over 200 countries with more than 40 million confirmed cases and one million deaths as of November 1,2020.The SARS-CoV-2 virus,leading to COVID-19,shows extremely high rates of infectiv...COVID-19 has spread globally to over 200 countries with more than 40 million confirmed cases and one million deaths as of November 1,2020.The SARS-CoV-2 virus,leading to COVID-19,shows extremely high rates of infectivity and replication,and can result in pneumonia,acute respiratory distress,or even mortality.SARS-CoV-2 has been found to continue to rapidly evolve,with several genomic variants emerging in different regions throughout the world.In addition,despite intensive study of the spike protein,its origin,and molecular mechanisms in mediating host invasion are still only partially resolved.Finally,the repertoire of drugs for COVID-19 treatment is still limited,with several candidates still under clinical trial and no effective therapeutic yet reported.Although vaccines based on either DNA/mRNA or protein have been deployed,their efficacy against emerging variants requires ongoing study,with multivalent vaccines supplanting the first-generation vaccines due to their low efficacy against new strains.Here,we provide a systematic review of studies on the epidemiology,immunological pathogenesis,molecular mechanisms,and structural biology,as well as approaches for drug or vaccine development for SARSCoV-2.展开更多
文摘知识追踪旨在评估学习者的学习状态,并根据先前的答题情况预测他们未来的答题表现.然而现有的知识追踪模型大多仅关注问题或技能间的关联,忽略了学生与问题间的结构关系.为此我们提出了基于学生问题关联的异构图知识追踪模型(StudentProblem association based heterogeneous graph Knowledge Tracing model,SPKT).该模型在知识追踪中融合了学生的学习能力和问题的重要性,并使用图注意力网络学习学生问题间的关联,获得学生、问题的嵌入表示并进行知识状态的预测.通过在真实公开数据集上的性能对比和模型消融实验,并可视化SPKT模型的知识追踪效果,证明了SPKT在预测性能上优于现有的知识追踪模型.
文摘During the development of mammalian heart, the left and right atria play an important role in cardiovascular circulation. The embryonic atrium is mainly formed by the differentiation of progenitor cells and the proliferation of cardiomyocytes, while the postnatal atrium is primarily shaped by the increase in the volume of cardiomyocytes. Cell proliferation and differentiation of atrial development is the basis for its functions such as “blood reservoir” and “supplementary pump”. Deep understanding the cellular mechanism of atrial development is imperative to explore the causes of common congenital arrhythmia heart diseases such as atrial fibrillation. We used genetically engineered mouse reproduction knowledge, lineage tracing method based on CreloxP system, molecular biology and immunofluorescence technology to track the cardiomyocyte lineage of Nppa-GFP mouse line with stereo fluorescence microscope and ultra-high-speed confocal microscope. Besides the atrium of Nppa-CreER;Rosa26 tdTomato mouse was examined during embryonic (E10.5 - E18.5) and postnatal (P0, P3, P5, P7, P14, P28, P8w) stage. Immunofluorescence results revealed that Nppa-positive cells labeled TNNI3-positive cardiomyocytes and protruded into the atrial cavity at the beginning of E11.5 - E12.0 and during subsequent development to form Nppa-positive myocardial trabeculae. Thick comb-shaped myocardium was observed after birth, and we suspect that this was particularly important for the normal contractile activity and pumping function of the atrium. Additionally, non-single origin of Nppa-positive trabecular myocardiocytes were revealed through Tamoxifen-induced lineage tracing experiment. Our findings reveal proliferation dynamics and non-comprehensive fate decisions of cardiomyocytes that produce the distinct architecture of the atrium chamber.
基金This research was funded by Hunan Provincial Innovation Platform and Talents Program(No.2018RS3105)the Natural Science Foundation of China(No.61803151)+2 种基金the Natural Science Foundation of Hunan province(No.2018JJ3570)the Project of Scientific Research Fund of Hunan Provincial Education Department(No 19A060 and 19C0185)the project to introduce intelligence from oversea experts to the Changsha City(Grant No.2089901).
文摘COVID-19 has spread globally to over 200 countries with more than 40 million confirmed cases and one million deaths as of November 1,2020.The SARS-CoV-2 virus,leading to COVID-19,shows extremely high rates of infectivity and replication,and can result in pneumonia,acute respiratory distress,or even mortality.SARS-CoV-2 has been found to continue to rapidly evolve,with several genomic variants emerging in different regions throughout the world.In addition,despite intensive study of the spike protein,its origin,and molecular mechanisms in mediating host invasion are still only partially resolved.Finally,the repertoire of drugs for COVID-19 treatment is still limited,with several candidates still under clinical trial and no effective therapeutic yet reported.Although vaccines based on either DNA/mRNA or protein have been deployed,their efficacy against emerging variants requires ongoing study,with multivalent vaccines supplanting the first-generation vaccines due to their low efficacy against new strains.Here,we provide a systematic review of studies on the epidemiology,immunological pathogenesis,molecular mechanisms,and structural biology,as well as approaches for drug or vaccine development for SARSCoV-2.
