Results 31 to 40 of about 9,698 (123)
Study on structures and activities of vegetable tannins [PDF]
, 2014 摘要 植物单宁由于其复杂多样的结构和特殊丰富的生物活性，在医药、食品、农业、材料、化工、林业、环境、生态等多学科领域得到了广泛的应用，逐渐成为植物化学、药理学和食品化学等交叉学科的研究热点。方便快捷而又精准可靠的化学结构鉴定分析能有效帮助我们筛选和开发具有重大应用价值的植物单宁资源。本研究应用基质辅助激光解吸附离子化飞行时间质谱（MALDI-TOFMS）、高效液相色谱-电喷雾电离质谱（HPLC-ESI-MS）、核磁共振（NMR）、化学降解法等方法联合分析鉴定不同植物来源单宁结构 ...
柴纬明
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Rare Metals, EarlyView.ABSTRACT The growing concern over human health issues, driven by increasingly severe electromagnetic pollution from 5G communication, has made the urgent development of high‐performance electromagnetic wave (EMW) absorbing materials. Although carbide‐based materials are promising because of their conductive and polarization losses, existing single ...
Chenqiang Duan +9 more
wiley +1 more source
Enzymatic Degradation of Alginate and in Vitro Immunological Activity of Its Degraded Products [PDF]
In this study, changes in the molecular mass of alginate were investigated during its enzymatic degradation and the processing parameters for the enzymatic preparation of alginate oligosaccharides were explored.
ZHANG Qian, QI Huimin, BIAN Bin, MA Junmei, LAI Chenhuan, HUANG Caoxing, LING Zhe, YONG Qiang
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Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract The nested subset pattern (nestedness) has been widely used to explain species distributions in island and fragmented systems. Mountain sky islands serve as critical natural laboratories for understanding the evolutionary consequences of geographic isolation and climate
Caiwen Zhang +5 more
wiley +1 more source
MONTE CARLO SIMULATION ON BULK RING-OPENING COPOLYMERIZATION OF OCTAMETHYLCYCLOTETRASILOXANE WITH N-β-AMINOETHYL-γ-AMINOPROPYLMETHYLDIMETHYOXYSILANE [PDF]
, 2004 应用MonteCarlo方法模拟八甲基环四硅氧烷与N β 氨乙基 γ 氨丙基甲基二甲氧基硅烷 (D4/APAEDMS)的本体开环共聚动力学 .在兼顾模拟精度与计算经济性基础上 ,模拟过程采用自由体积理论简化处理扩散效应并与本征反应动力学耦合 .本征动力学常数通过模拟主要共聚基元反应得到 ,基于优化的动力学常数通过模拟从分子水平揭示 :(1 )D4/APAEDMS本体开环共聚存在总活性基团的“稳态”行为 ;(2 )D4/APAEDMS本体开环共聚反应过程的重均分子量与数均分子量以及分子量分布系数存在“突变”
罗正鸿 +3 more
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Conservation Biology, EarlyView.Abstract Despite the crucial role of human impacts on biodiversity loss, many assessments of this loss focus on single metrics, such as species richness, and overlook the multidimensional effects of human activities. Because of its importance to ecosystem functioning, we investigated the functional diversity of medium‐ and large‐sized mammal ...
Xueyou Li +8 more
wiley +1 more source
Conservation Biology, EarlyView.Abstract Achieving global conservation policy goals requires the ability to set and measure progress toward science‐based targets for biodiversity. The species threat abatement and restoration (STAR) metric was developed to enable actors to set science‐based targets for species.
Louise Mair +17 more
wiley +1 more source
Biogeochemical implications of mangrove plant polyphenols and their antioxidant activities [PDF]
, 2012 植物多酚由于其特殊多样的生物化学活性，逐渐成为化学生态学、生物地球化学、药理学和食品化学等交叉学科的研究热点。红树植物多酚具有多样性含量分布和结构组成是红树林与环境长期协同进化的结果。有关红树植物多酚生物地球化学及结构-活性的研究在国际上处于起步阶段。本研究联合多种分析技术，包括13C-NMR、MALDI-TOF质谱、正相/反相HPLC-ESI-MS，凝胶色谱柱法，化学降解法，比色法等，研究了植物多酚在红树林湿地生态系统的生物地球化学循环及结构与抗氧化活性关系，为揭示红树植物的营养保存机制奠定理论基础 ...
周海超
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Attainment Pairing Effects on Cognitive Conflict in Technology‐enhanced EFL Cooperative Tasks
International Journal of Applied Linguistics, EarlyView.ABSTRACT This study examines how attainment pairing (high‐high versus high‐low versus low‐low attainment) impacts English as a Foreign Language (EFL) learner engagement during technology‐enhanced cooperative writing tasks. Seventy‐eight Chinese university learners formed 39 dyads (13 pairs per group) via Tencent Meeting.
Ying Liu, Allen Thurston
wiley +1 more source
The MALDI-TOF MS of Vegetable Tannins [PDF]
, 2007 在对植物单宁重要的生态功能，显著的生理学、药理学活性，对人体、家畜健康的重大影响、巨大应用价值和新用途的开发等领域的研究中，都需要对植物单宁的化学结构进行快速、简便且准确地分析。基质辅助激光解吸附离子化飞行时间（MALDI-TOF）质谱对分析多分散的植物单宁聚合物是一种理想的工具。本文着重对1）样品在MALDI过程中的裂解对准确分析单宁结构的影响，2）样品前处理过程对准确分析植物单宁结构的影响，3）MALDI-TOF质谱与13C-NMR联合应用于未知缩合单宁的结构分析等作了深入的探讨。通过本部分的研究 ...
向平
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