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101.
日本平面设计大师田中一光设计的戏剧海报作品中,能剧海报独树一帜。能剧海报多以日本传统的能面形象为基本元素,结合理性严谨的方格骨格,采用热情饱满的日本民族色彩,巧妙处理虚实关系,是民族与国际、传统与现代完美结合的典范。  相似文献   
102.
Objective: To investigate whether vascular endothelial growth factor (VEGF) gene plasmid carried by polytetrafluoroethylene (PTFE) vascular graft materials could transfect endothelial cells (ECs) and promote their growth. Methods: PTFE vascular graft materials carried with pCDI-hVEGF121, pCDI or pEGFP were incubated in Tris-buffer solution and the values of optical density of 260 nm at different time were plotted, then the DNA controlled release curve was made. ECs derived from human umbilical vein were seeded on the pCDI-hVEGF121/pCDI/pEGFP-PTFE materials or tissue culture plates, ECs numbers were counted and VEGF protein concentrations at different time were measured by enzyme-linked immunoadsorbent assay method. Green fluorescent protein (GFP) expression in ECs on pEGFP-PTFE materials was examined with fluorescence mi- croscopy. Results: The controlled release curve showed that the gene released from PTFE materials was rapid within 8 h, then slowed down and that the gene released continuously even after 72 h. At 24, 72 and 120 h, ECs number and proliferation rate of pCDI-hVEGFI21-PTFE materials were higher than those ofpCDI or pEGFP-PTFE materials (P〈0.05). VEGF protein concentration of pCDI-hVEGF121-PTFE materials was higher than that of pC DI or pEGFP-PTFE materials at 6, 24, 72 and 120 h (P〈0.01). GFP expression in ECs on the pEGFP-PTFE materials could be detected by fluorescence microscopy. Conclusion: PTFE graft can be used as a carrier of VEGF gene plasmid, VEGF gene carried by PTFE can transfect ECs and promote ECs growth.  相似文献   
103.
ABSTRACT

Subject ontology can help implement the structured organization of knowledge for online learners and thus plays an important role in the learning process. However, building ontologies by experts is time-consuming, and the adaptation of such ontologies to different contexts might be a problem. Crowdsourcing, which allows users to build and refine ontologies during their learning process, has exhibited potential for solving this problem. In this study, a crowdsourcing mode-based learning activity flow approach is proposed to guide the learning of online learners while promoting the generation and evolution of subject ontologies using the learners’ contributions to the learning content. This flow makes full use of the learners’ wisdom during the learning process to promote self-regulated learning as well as the generation and evolution of the ontology. Based on the proposed approach, a learning support system was developed and an experiment conducted involving a Chinese lesson on “The Liangzhou Poem”. In the experiment, student participants built 722 triples, of which 584 evolved as formal items in the subject ontology. Moreover, all learners were able to construct a well-organized knowledge graph. Students in both high- and low-scoring groups contributed valuably to the knowledge generation and evolution of the subject ontology. Furthermore, while the widths of the knowledge constructed by students in high- and low-scoring groups were similar, their depths were substantially different. During this process, the crowdsourcing-based activity flow system achieved satisfactory technique acceptance, which means that the proposed approach and system are useful for the effective generation of subject ontologies while helping learners acquire knowledge.  相似文献   
104.
运用非线性分岔理论并结合数值仿真,针对具有快慢时间尺度的细胞内钙振荡的数学模型,研究具有重要生理意义且在实验中容易调控的单参数变化时钙离子不同类型的振荡行为。基于Izhikevich提出的分类方法,在Borghans-Dupont模型中分别得到了拟周期型簇振荡等多种簇振荡模式。  相似文献   
105.
通过观察不同剂量二甲基亚砜(dimethyl sulfoxide DMSO)作用下PC12细胞形态和生长状态的变化,确定PC12细胞对DMSO的耐受剂量.按照一定浓度梯度(V/V)将DMSO加入培养液干预后的24、48和72 h于倒置相差显微镜下观察AO/EB染色前后细胞的形态特征,同时用四甲基偶氮唑蓝(MTT)显色法检测细胞的生存率和计算半数抑制浓度(50%inhibiting concentration,IC50).结果表明:DMSO浓度为14 mL/L时,24 h内90%的PC12细胞生长正常,形态完整,活力与对照组比较无差别,浓度提高到20 mL/L时,24 h时细胞生存率可下降27%,随着作用时间延长,细胞生存率进一步降低;24、48和72 h对应的IC50值分别为31.4、23.9和19.2 mL/L.因此,对PC12细胞而言,24 h内的应用终浓度应低于14 mL/L,干预时间如需延长,DMSO的应用剂量应相应降低.  相似文献   
106.
Surface engineering of synthetic carriers is an essential and important strategy for drug delivery in vivo. However, exogenous properties make synthetic nanosystems invaders that easily trigger the passive immune clearance mechanism, increasing the retention effect caused by the reticuloendothelial systems and bioadhesion, finally leading to low therapeutic efficacy and toxic effects. Recently, a cell membrane cloaking technique has been reported as a novel interfacing approach from the biological/immunological perspective, and has proved useful for improving the performance of synthetic nanocarriers in vivo. After cell membrane cloaking, nanoparticles not only acquire the physiochemical properties of natural cell membranes but also inherit unique biological functions due to the presence of membrane-anchored proteins, antigens, and immunological moieties. The derived biological properties and functions, such as immunosuppressive capability, long circulation time, and targeted recognition integrated in synthetic nanosystems, have enhanced their potential in biomedicine in the future. Here, we review the cell membrane-covered nanosystems, highlight their novelty, introduce relevant biomedical applications, and describe the future prospects for the use of this novel biomimetic system constructed from a combination of cell membranes and synthetic nanomaterials.  相似文献   
107.
108.
基于时序LAI的地块尺度玉米长势监测方法   总被引:1,自引:0,他引:1  
农作物长势监测可为田间管理措施调整和农作物产量预测提供及时、准确的信息。针对中国地块面积小的情况,本文采用中高分辨率的多源遥感影像Landsat-7 ETM+影像、Landsat-8 OLI影像、高分一号(GF-1)影像、HJ-1 A/B卫星影像为数据源;针对目前过多依赖NDVI等易饱和植被指数的问题,研究中选择LAI为长势监测指标,并利用PROSAIL辐射传输模型反演LAI,以保证该指标的准确性;长势实时监测采用RPLAI、LVCI、MLVCI指标,从多个角度表征长势的实时监测结果。研究结果表明:①同时相GF-1影像和Landsat-8 OLI影像具有较高的相关性,2种影像在近红外波段、绿波段、红波段的相关性决定系数R2分别为0.9320、0.7339、0.7153。②基于PROSAIL模型可以反演得到高精度的LAI,基于时序LAI的玉米生长过程监测结果表明:2015年,黑龙江农垦总局八五二农场6月下旬玉米冠层LAI快速增加,7月底、8月初LAI达到最大,并持续一段时间,进入8月下旬后,LAI开始下降。③利用RPLAI、LVCI、MLVCI指标对研究区玉米长势实时监测的结果表明,与2011—2014年相比,2015年八五二农场玉米长势一般,研究区北部长势较好,南部区域长势较差。从研究结果我们得出如下结论:①同时相的Landsat-8 OLI影像与GF-1遥感影像,经过相对辐射定标后可以结合使用于农作物长势监测中;②利用PROSAIL模型反演时序LA,可用于地块尺度的农作物长势精细监测。  相似文献   
109.
采用BONNER法提取鸡和大白鼠肝细胞染色质的组成成分进行比较分析,结果表明:两者紫外吸收光谱非常相似,在220 nm和260 nm呈现两个吸收峰。鸡肝染色质组成成分DNA∶RNA∶组蛋白∶非组蛋白的质量液度的比值为:1∶0.096∶0.963∶0.53;大白鼠肝细胞染色质组成成分DNA∶RNA∶组蛋白∶非组蛋白的质量液度的比值为:1∶0.077∶1.007∶0.55。  相似文献   
110.
Ku波段教育卫星系统是针对农村地区地理情况和经济状况开展“校校通”工程提出的一种可行性方案,我国从1999年就开始了这方面的实践,湖北省从今年开始启动“曙光行动计划”专项项目。从湖北省贫困地区应用情况来看,这个系统普遍受到了师生的好评,但是还有些问题需要注意,为了实施好这项工程,笔者提出了一些建议。  相似文献   
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