辽宁苦菜中总黄酮含量及抗氧化性能分析

对辽宁苦菜中总黄酮的含量和抗氧化性能进行研究.采用索氏提取法,以70%乙醇溶液为提取溶剂对苦菜中的黄酮类化合物进行提取,通过光谱分析法测定其含量,并利用流动注射化学发光法测定其抗氧化性能.结果表明辽宁苦菜中总黄酮的含量为88.18 mg/g,苦菜总黄酮抗氧化的IC50为0.62 mg/mL,由此说明辽宁苦菜中总黄酮的含量较高,且具有较强的抗氧化性能.     

豚草水浸液对小麦种子萌发及幼苗生长的影响

研究不同浓度的豚草水浸液对小麦种子萌发及幼苗生长的影响.结果表明：小麦种子发芽率总体随着豚草水浸液浓度的升高而显著下降;对小麦幼苗初生根的伸长具有显著的抑制作用,但对小麦苗高的抑制作用程度稍弱;显著增强小麦幼苗茎叶的超氧化物歧化酶、过氧化物酶的活性.浓度效应明显.     

二语写作中母语思维迁移影响实例分析

母语思维产生的负迁移会阻碍学习者二语写作水平的提高,许多教育研究者主张学习者在二语写作中避免母语思维而直接运用二语思维,从而规避负迁移对写作产生的阻碍。通过实例调查和分析,发现在二语写作中母语思维负迁移影响并不显著,因此＂避免母语思维＂的要求不能一概而论,应因人而异、合理要求。     

糖类及其衍生物对马铃薯块茎形成的影响

采用可溶性单、双糖模拟高浓度蔗糖,并使用糖的吸收代谢抑制剂对氯汞基苯磺酸、根皮苷、葡萄糖胺和糖类衍生物的添加等方法探讨高浓度糖在马铃薯（Solarium tuberosum L．）块茎形成中的作用．结果表明,高浓度蔗糖诱导块茎发生,不是通过其产生的渗透胁迫因子实现,葡萄糖和蔗糖诱导结薯不是因为膜两端的浓度差引起,可能是跨膜运输或胞内代谢引起．对氯汞基苯磺酸能阻断蔗糖诱导结薯作用,但对葡萄糖诱导作用无显著影响．根皮苷能部分阻断蔗糖诱导结薯作用,可完全阻断葡萄糖诱导结薯作用．蔗糖诱导块茎形成主要通过蔗糖本身来实现．葡萄糖胺对蔗糖和葡萄糖诱导结薯作用无显著影响．2-脱氧葡萄糖、3-氧-甲基葡萄糖、L型葡萄糖不能诱导块茎形成．     

树脂法吸附提取扶桑花红色素的研究

以扶桑花为原料,用树脂法吸附提取扶桑花红色素,得到最佳提取工艺条件.实验结果表明,HPD-300树脂对扶桑花红色素的吸附效果最好,用80%乙醇作洗脱剂,可获得优质天然红色素.HPD-300树脂稳定性良好,使用8次后,其吸附能力无明显减弱.     

Meaningfulness is in the eye of the reader: eye-tracking insights of L2 learners reading e-books and their pedagogical implications

This study employed eye-tracking technology to probe the online reading behavior of 52 advanced L2 English learners. These participants read an e-book containing six types of multimedia supports for either vocabulary acquisition or comprehension. The six supports consisted of three micro-level supports that provided information about specific words (glosses, vocabulary focus, and footnotes), and three macro-level supports that provided global or background information (illustrations, infographics, and photos). The participants read the ebook under two presentation modes: (1) simultaneous mode: where digital input and supports were presented at the same time; and (2) sequential mode: where the digital content and supports were incrementally presented. Analyses showed that when reading for vocabulary acquisition, vocabulary focus and glosses were significantly fixated on, and when reading for comprehension, illustrations were more intensely fixated on. Additionally, when the digital content was incrementally presented, vocabulary focus received significantly higher total fixation duration. This suggests that reading under the sequential mode has the potency to guide L2 learners’ focal attention toward micro-level supports. In contrast, under the simultaneous presentation mode, L2 learners seemed to divide their focal attention among both micro-level and macro-level supports. Pedagogical implications are discussed based on the findings of this study.     

Cd~(2+)对龙葵根尖细胞有丝分裂的影响

采用不同浓度的氯化镉溶液处理龙葵根尖,通过常规染色体压片技术,观察其根尖分生组织细胞有丝分裂的情况及染色体的变化.结果表明,随氯化镉溶液浓度升高和处理时间的延长,其根尖生长速度和有丝分裂指数降低,并能引起染色体畸变和微核现象.说明氯化镉对龙葵根尖细胞有丝分裂有一定的抑制作用,具有一定的遗传毒性效应.     

母语在外语教学中的积极作用

在外语教学中使用母语对学习者进行帮助是提高语言学习者学习积极性的重要手段之一,使用母语能够简化对目标语言的理解,同时提升学习者的学习自信心。     

第二语言能力的内涵分析及其对外语教学的启示

文章分析了乔姆斯基的语言能力观与海姆斯的交际观,认为语言是交际的手段。理想的外语学习者的外语能力应包括正确运用语言,在目的语文化场景中实现得体交际的能力。正确理解语言能力以及外语能力的构成有助于提高我国当前外语教学设计的合理性和教学效果。     

Preservice teachers’ implementation of formative assessment in English writing class: Mentoring matters

This multiple-case study investigated the experience of three preservice teachers who attempted formative assessment (FA) strategies in their English as a second language writing class during their teaching practicum in a secondary school in Hong Kong. Based on data from 17 lesson observations and 24 interviews, the study examined the three teachers’ implementation of FA strategies during cycles of pre-, while- and post-writing stages. Also analyzed are the teachers’ reflections on and their mentors’ and students’ evaluation of their FA implementation. The study found the teachers could translate their understanding of FA principles into teaching and assessment strategies appropriately, but the school’s accountability culture worked against their innovation. School mentors’ open-mindedness and support to their FA attempts were found to be crucial. The findings are discussed centering on key issues in the relational, developmental and contextual dimensions of the teaching practicum and their impact on preservice teachers’ practice and attitude.