40,770 research outputs found

    Synthetic Study towards Periconiasin A

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    具有生理活性的天然产物不仅是药物学家研究的对象,而且一直以来都备受有机合成化学家的关注。数据统计,1981年初至2014年底这34年间,所有新批准的药物中有46%药物来源与天然产物有关,而抗肿瘤药物的比例更是高达57%,可见天然产物对于新药研发具有重大意义。本论文以高效的策略对具有良好生理活性的杂合天然产物PericoniasinA进行不对称全合成研究。 细胞松弛素类化合物PericoniasinA是2013年由中国医学科学院药物研究所戴均贵研究员等人从刺果番荔枝内生菌Periconiasp.F-31的次级代谢产物中分离得到的一种杂合天然产物。本文中的杂合天然产物是指由两种或更多不同的基本代...Biologically active natural products attract the attention not only pharmacologists but also from synthetic organic chemists. It was showed that 46% of all newly approved drugs between 1981 and 2014 are related to natural products. Furthermore, as high as 57% of new antitumor drugs in the same period are natural products or their derivatives. It means natural products are a significant resource fo...学位:理学硕士院系专业:化学化工学院_有机化学学号:2052013115158

    Total Synthesis of Hapalosin and Its Analogues:Construction of Three Small Hapalosin C-9 Analogues Libraries and Studies on Total Synthesis of Melleumins A and B

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    环肽类化合物是一类结构复杂多样的天然产物。自然界中存在大量的环肽类化合物,表现出多种生物活性,如杀虫、抗菌、抗肿瘤、抗病毒、和免疫抑制等。环肽类化合物作为富有实用前景的先导化合物在药物发现中受到越来越多的关注,新的活性天然产物也不断被发现。同时,环肽类天然产物的全合成也成为不对称合成的新热点。Hapalosin(1a)是1994年从蓝藻中分离提取的一类新型结构的环肽化合物,因其对肿瘤细胞的多药耐药性细胞系有很强的抑制作用,一经发现就引起了广大合成化学家和药物化学家的关注。本论文的目标在于拓展手性合成砌块(R/S)苹果酰亚胺的多用性,将其应用于环肽类天然产物hapalosin和melleumin...Cylcopeptides with complex and diversified structures are widespread in nature. Many of them exhibit various biological activities, such as, antibiotics, antitumor, antivirus, immunosuppressive effect and pesticides. As promising lead compounds in drug discovery, cylcopeptides are receiving more and more attention. And the studies on the asymmetric total synthesis of these compounds have been a ne...学位:理学博士院系专业:化学化工学院_有机化学学号:B20022501

    Study on Natural Products from Five Edible and Medicinal Macrofungi

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    天然小分子化合物种类繁多、数量巨大,不但具有化学调节、信号载体、化学防御等多种生理作用,而且是药物开发的重要资源。组合生物合成等技术可以定向合成与创造新的天然产物衍生物,但作为药物发现的工具还有待进一步发展和完善。天然产物的多样性是任何科学家无法想象的,仍然是新药研发的重要先导化合物。食药用大型真菌是产生新结构与具有活性天然小分子化合物的重要生物类群。近年来,越来越多的食药用真菌可以通过液体发酵或固体发酵方式来大量培养,而且它们发酵产物的营养价值与化学成分含量远高于天然或人工栽培的子实体或菌核。因此,研究食药用真菌发酵产生的天然小分子化合物的多样性与活性已成为天然产物化学家与真菌学家共同关注的...Large quantity of natural products with different structure types have not only been focused on the study of functional molecules for the organism in the fields of chemical defense, chemical regulation and signal transduction, but also played a vital role in the discovery of new pharmacy. Many natural product derivatives with specific structure can be produced through combinatorial chemistry and o...学位:理学博士院系专业:生命科学学院生物化学与生物技术系_微生物学学号:2012005140313

    GoGlobal Rural-Urban

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    This is a book of edited articles and design projects from five years of collaborative international design projects in developed and developing economies, including China, Thailand, Ghana and Japan. Part One contains articles on initiatives including e-commerce models for developing economies, massclusivity and craft design. Part Two is dedicated to design solutions for China’s rural-urban migration issues, which affect 55 million people a year. The project enhances knowledge about the application of design thinking to national-level issues connecting policy to implementation, extending design activity into large-scale social and economic areas. The book follows an exhibition of design outcomes in London and Beijing (2010). Hall developed his chapter (‘Go Global: Ghana’) from a conference paper given at the ‘International Association of Societies of Design Research Conference’, South Korea (2009) and further expanded as a book chapter (with Barker) entitled ‘e-Artisans: Contemporary design for the global market’ in Global Design History (2011). ‘eArtisans’ researched a proposed e-commerce model linking designer-craftsmen with a global Internet sale and distribution model for African countries. The originality lay in proposing and testing knowledge, through design collaborations, in a combination of e-commerce enterprise models; it was significant in deploying the proposed model in an experimental educational initiative. The research was based on previous experience of design, craft and enterprise projects in Thailand and China, and aligned with a creative economies report by UNESCO (2008). The context was a collaboration at the KNUST, Kumasi, Ghana, where action-based research methods resulted in a case study illustrating cultural transfer. Support and partnership were also provided by Aid To Artisans, the British Council and Africa 53. A vital aspect was the discovery of how an e-commerce model changed design concepts and creative proposals. The GoGlobal project has continued with an edited publication, Designing Social City Experiences (Jin Nam and Hall 2013)

    The Screening of Antifungal Activities of Specific Environmental Fungi and Studies on Chemical Components of 8 Fungal Strains

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    真菌感染性疾病一直危害着人类的健康。在治疗真菌感染的过程中,抗真菌药物的发展过程经历了大约三个阶段:早期以天然产物药物灰黄霉素和两性霉素为主;20世纪80年代后以唑类为代表的合成药物是研究的热点;近几年系统真菌感染在临床发病率逐年增加、耐药性病原真菌不断出现的时候,echinocandins类药物的上市和sordarins类化合物成为热点预示着天然产物重新成为抗真菌药物研究的重点。 自然界天然产物数量巨大,种类繁多,在生命过程中起着生理调节、信号传递以及化学防御等重要作用,而且有活性的天然产物又是药物开发的重要资源。真菌是能够产生新结构天然产物的重要生物类群之一。特异环境真菌,包括海洋真菌和...Fungal diseases have long endangered mankind's health. During the process of curing fungal infections, the development of antifungal agents experienced three stages. In early days natural product medicines griseofulvin and amphotericin B are the major. Since1980’s, synthetic azoles is the major class of antifungal agents in clinic. The last few years, new antifungal agents echinocandins were used ...学位:理学博士院系专业:生命科学学院生物学系_微生物学学号:2012005140313

    Greenhouse gas emissions from croplands of China

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    China possesses cropland of 1.33 million km 2. Cultivation of the cropland not only altered the biogeochemical cycles of carbon (C) and nitrogen (N) in the agroecosystems but also affected global climate. The impacts of agroecosystems on global climate attribute to emissions of three greenhouse gases, namely carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)
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