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心理学研究方法中定量研究和质性研究的发展与整合*杨智辉【摘要】 心理学研究所采用的主要的两种方法是定量研究与质性研究。
这两种研究方法长期处于对立的研究范式当中。
二者在产生背景,哲学基础,基本方法等方面都各有所长。
定量研究在过去一直处于一种占绝对的统治地位,随着认识的深入和研究思路的突破,两种研究方法都有所改进和发展,势必走向一条整合之路。
【关键词】 心理学研究方法;定量研究;质性研究;综述The Trends and Combination of Quantitative and Qualitative Researches in Psychological Research Methods.Y ang Zhihui.D ep ar tment of Psy chology,S chool of H umanities and Social Sciences,Beij ing Forestry U niver sity,Beij ing100083,P.R.China1 心理学研究方法的发展过程 心理学研究方法的发展犹如心理学的发展一样有着一个悠久的过去,但只有一个短暂的历史。
在公元前4世纪,亚里士多德的《灵魂论》就已经开始从哲学层面对某些心理现象的实质和规律进行讨论。
但两千多年来哲学家们几乎都是采用基于内省、推理或个人主观经验等“思辨”类的方法来分析心理现象,直到1879年冯特创立第一个心理学实验室,采用实验的研究方法才使得心理学成为一门独立的学科。
在科学心理学创立的19世纪,自然科学取得了突飞猛进的进步。
生理学、医学、物理学、化学等自然科学取得了巨大的成就。
许多学科都以自己能成为一门自然科学或使用科学的方法为荣,而心理学就是在这样一种氛围下成长起来的。
因此,心理学自建立之日起心理学家们就致力于将其发展成为一门使用科学方法的真正的自然科学。
随着研究工具和方法的不断改进,使得之前只能用“思辨”类方法来研究的心理现象能够采用实验等方法来加以研究,这种定量研究的方法取得了诸多有价值的成就,对心理学成为一门独立的学科和走向客观与精确化的道路作出了不可磨灭的贡献。
姓名：张丽静学号：2009310338 专业：英语语言文学Quantitative and Qualitative Research:Distinctions and Compatibility IntroductionQuantitative research and qualitative research are two different types of research strategies. They represent two different paradigms of social research, in other words, they are two different general orientations to the conduct of social research. Because of their differences in their emphasis of epistemological and ontological issues, there have always been contentions over them in the social research field such as: which strategy is much more scientific? Which one should be adopted more frequently in social research process? Etc. All these contentions form the competing situation of the two paradigms. In the competition, although each of their strengths may increase or decrease in different historic period, none of them can overwhelm or replace the other. This condition can show us that both the two kinds of research strategies are indispensable in the process of social research. They exist with their own value and they have their own strengths and weaknesses. This assignment is designed to analyze the contentions over the two kinds of social research strategies, attempting to discover whether there is compatibility between them although they have a lot of distinctions. Also, through these efforts, this thesis tries to tell the readers what kind of attitude we should hold toward the two different research strategies while doing social research. This thesis starts with defining the two research strategies, followed by various distinctions between them then their overlaps in different ways. After these analyses, it will discuss the strengths and weaknesses of the two research strategies respectively, and finally point out the necessity to view them with a justified attitude and to combine them together in the social research process.Definitions of Quantitative and Qualitative ResearchAccording to Bryman, research strategy means a general orientation to the conduct of social research and quantitative and qualitative research form two distinctive clusters of research strategy. Quantitative research emphasizes quantification in the collection and analysis of data while qualitative research usually emphasizes words rather than quantification in the collection and analysis of data.In the social sciences, quantitative research refers to the systematic empirical investigation of quantitative properties and phenomena and their relationships. The objective of quantitative research is to develop and employ mathematical models、theories or hypothesis pertaining to phenomena. The process of measurement is central to quantitative research because it provides the fundamental connection between empirical observation and mathematical expression of quantitative relationships. Quantitative research is widely used in social sciences such as sociology, anthropology, and political science. Research in mathematical sciences such as physics is alsoquantitative by definition. In the social sciences, the term relates to empirical methods, originating in both philosophical and the history of statistics, which contrast with qualitative research methods.As to the definition of qualitative research, this part of this thesis will employ Cresswell‘s (1994) definition as follows:Qualitative research is an inquiry process of understanding based on distinct methodological traditions of inquiry that explore a social or human problem. The researcher builds a complex、holistic picture, analyzes words, reports detailed views of informants, and conducts the study in a natural setting.(Creswell, 1994: 210)Qualitative research is multi-method in focus, involving an interpretive, naturalistic approach to its subject matter. This means that qualitative researchers study things in their natural settings, attempting to interpret phenomena in terms of the meanings people bring to them.Qualitative research involves the studied use and collection of a variety of empirical materials such as case study, personal experience, life story interview, observational, historical, interactional, and visual texts which describe routine and problematic moments and meaning in individuals' lives.The layouts of definitions of the two types of research strategies are important here because they are prerequisite to the understanding of the following discussion about their distinctions and overlaps, and they are helpful for us to form the required attitude toward the two research strategies.The distinctionsAccording to the former discussions, quantitative research and qualitative research are two main schools of research strategies and although they are often used in tandem, they are still two different methods and they differ with each other in many ways. Martyn Hammersley pointed out in his book that the distinctions between quantitative and qualitative research have become the key issues in methodological discussions within psychology and the social sciences, and no doubt that they are of great importance in guiding people while doing social research.At the most basic level, quantitative research methods are used when something needs to be measured, while qualitative research methods are used when a question needs to be described and investigated in some depth. There is a close relationship between theory and research strategy, and as to this, quantitative research take a deductive approach to this relationship, in which the emphasis is placed on the testing and confirmation of theories. But qualitative research predominantly emphasizes an inductive approach to this relationship between theory and research, in which the emphasis is laid on the generation and emergence of theories.Any kind of research strategies in the social research process must has its own foundations in the beliefs of philosophy, and the two kinds under the discussion in this thesis are no exceptions. The philosophical foundations of both the two kinds of social research strategies are also different from each other. As to the epistemological orientation, quantitative research manifest the practice and norms of natural scientific model and of positivism in particular while qualitative research reject this in preference for an emphasis on the ways in which individuals interpret their social world. Ontologically, paralleled to the orientation mentioned above, quantitative research adopted objectivism while qualitative research prefers constructionism.At the level of the collected data‘s nature, quantitative and qualitative research involves the use of different sorts of data. On the one hand, quantitative research uses the ‗hard data‘which is numerical and reliable, and on the other hand, qualitative research adopted the ‗rich data‘ which is verbal and deep. The images of social realities in quantitative researche rs‘ eyes are external and objective, but to the qualitative researchers, they are socially constructed. During the process of researches, the quantitative research strategy is much more structured than qualitative strategy which aims at explore the actor‘s interpretations of events, and quantitative research‘s purpose is to quantify the collected data.The distinctions discussed above can not cover every aspect but they can represent the most important areas. The table blow will show the distinctions in a clear way and although it is not comprehensive enough, it can present us the main concerns of this part in a good way.——based on Hammersley(1998); Bryman(2004)Within the social sciences, quantitative research and qualitative research represent two opposing schools of thought. One holds that fields like sociology and psychology should attempt to be as rigorous and quantitative as possible, in order to yield results that can be more easily generalized, and in order to sustain the respect of the scientific community. Another holds that these fields benefit from qualitative research, as it allows for a richer study of the subject, and allows for information to be gathered and analyzed in a subjective way that would otherwise be entirely missed by a quantitative approach. Although attempts have been made in recent years to find a stronger synthesis between the two, the debate rages on, with many social scientists falling sharply on one side or the other. Then we may have the questions like this: are the two research strategies really so different from each other that there have been so sharp contentions over them? Whether there is compatibility between them? This would be the discussions in the following part.The overlapping pointsThere are distinctions between quantitative and qualitative research in terms of their collected data and the ways through which the data are analyzed in the process of social researches, also there are differences in terms of their relationship with theory, their epistemological and ontological commitments, etc. However, all these distinctions are not hard-and-fast ones which can not be transcended. It is true that there are many researches that adopt only numerical data and many others that use only verbal data, but there are also a large proportion of studies that use both. There are contrasts which can be found between numerical and verbal data—the precision and imprecision, the structuredness and unstructuredness, etc. but all of the contrasts are not as stark as we imagined. Rather, there is a range from more to less precise and from more to less structured to the data in the process of research. It‘s just a matter of degree.The epistemological and ontological commitments are associated with certain research methods. The often cited links are between a natural science epistemology (positivism in particular) and social survey research, and between an interpretivist epistemology (such as phenomenology) and qualitative interviewing. However, these connections are not deterministic. That is to say, while qualitative research strategy may reveal a predisposition towards or a reflection of an interpretivist‘s or constructionist‘s position, the case is not always like this. The connections between epistemology and ontology on the one hand, and research strategies on the other are a kind of tendencies rather than definitive connections. Hence the discussion of the overlapping points between quantitative research and qualitative becomes the central issue in this part.In the social research field, there are aspects of quantitative research that can contain elements of interpretivism; also there are aspects of qualitative research that may contain elements of positivism.The relationship between qualitative research and positivism:Historically, positivism has been the dominant approach in the philosophy of science and most quantitative researchers tend to employ positivism as their epistemological underpinning. That would be why positivism has long been identified as the epistemology of quantitative research. However, it can be argued that some of the procedures of qualitative research can also reflect the perspectives on which positivist insist. Qualitative work can be positivist, which means it can attempt to document practices that lead consistently to one set of outcomes rather than another, to identify characteristics that commonly are related to some policy problem, or to find strategic patterns that hold across different venues and with different actors. One research done by Kathryn Edin (1991) on the coping strategies of welfare recipients can show these positivist approaches in qualitative research. Bases on extended and repeated interviews with welfare recipients, she described the difficulty mothers have in supporting themselves on welfare payments, the frustration they feel, and the many methods they develop to stretch an insufficient income. Through her observation of what welfare recipients do, which is to solicit contribution from family and to work in either undocumented or underground work to meet their basic needs, she suggested that it is reasonable to assume that other recipients cope in the same way as her respondents, given similar gaps between welfare payments and costs of living in other locations across the country. Her argument‘s force, in fact, depends on the generalizability of this pattern. If what she found indeed is repeated for other welfare recipients in other locales, her argument for reform is strengthened.From the above example it can be concluded that qualitative research may not only adopt interpretivist approach in the social research field, it can also hold the positivist attitude which is usually held by quantitative researchers. The differences in interpretivist and positivist qualitative work are differences in the questions one asks of the data and the types of conclusions one wishes to draw. Both forms of qualitative work look for details about preferences, motivations, and actions that are not easily made numeric. Positivist work, however, seeks to identify those details with propositions that then can be tested or identified in other cases, while interpretive work seeks to combine those details into systems of belief whose manifestations are specific to a case. While both in the end can comment about general principles or relationships, positivist work does so by identifying general patterns, interpretivist work does so by showing how the general pattern looks in practice.The relationship between quantitative research and interpretivism:Bryman pointed out in his book that qualitative research doesn‘t have a sole monopoly of the ability to study meaning. The qualitative method proponents essentially claim that it is only through qualitative research that the world can be studied through the eyes of people who are studied, but in fact, quantitative researchersalso frequently address meanings. An example cited by Bryman is the well-known concept of ―orientation to work‖ associated with the Affluent Worker research in the 1960s, which sought to uncover the nature and significance of the meanings that industrial workers bring with them to the workplace. Similarly, survey research by Steward et al. (1980: 112) showed that clerks should not be treated as a unitary category and that ―the meaning of clerical work will not be the same for all engaged in it‖. The widespread inclusion of questions about attitudes in social surveys suggests that quantitative researchers are interested in matters of meaning. It might be objected that survey questions do not really focus on issues of meaning because they are based on categories devised by the designers of the interview schedule or questionnaire. Also, as Marsh (1982) has pointed out, the practice in much survey research of asking respondents the reasons for their actions also implies that quantitative researchers are frequently concerned to uncover issues of meaning. For example, she cites Brown and Harris‘s (1978) research, which was based on a social survey, on the relationship between critical life events (such as loss of job, death of husband) and depression. In this research, exploring the meaning of critical life events for respondents was a notable feature of the questioning. As Marsh (1982: 115) puts it, ―it is the meaning that these events have for the subjects that gives them their causal force in provoking an onset‖. Examples such as those further point to the possibility that the gap between quantitative and qualitative research is not as wide as is sometimes supposed, and there are overlaps between the two kinds of research strategies.The strengths and weakness of the two research strategies Based on the discussions in the former parts, it can be seen that quantitative and qualitative research are just two different research strategies in the process of social research, they do have distinctions with each other and there do exist contentions over them, but they also have overlaps in many aspects, especially in their epistemological and ontological orientations. There are no such sayings as which method is the better one or which one is more scientific, they are just two different orientations in the conduct of social research, each carry with them their own strengths and weakness.Quantitative research collects data which can be analyzed mathematically, this means that its research process is objective and precise and it can eliminate prejudices. Quantitative research can produce statistical results that are accurate and powerful, meaning that it can make very fine distinctions tested groups, but sometimes it may suffer from over-specificity, producing results which are trivial or even difficult to interpret in meaningful terms. The conduct of this research strategy may often be restricted by some social conditions or ethical issues.Qualitative research takes measurements that are difficult to analyze mathematically. Statistical techniques for qualitative research are far less powerful than quantitative research, but qualitative data usually contains much more information, and is often easier to interpret and more meaningful to real-world situations thanquantitative results. The process of qualitative research is subjective, the result is less precise, but it‘s relatively easy to conduct. The strengths of qualitative research derive primarily from its inductive approach, its focus on specific situations or people, and its emphasis on words rather than numbers. Through qualitative strategies, researchers can understand meanings, and qualitative research has an inherent openness and flexibility that allows you to modify your design and focus during the research to understand new discoveries and relationships.ConclusionIn this paper, through the discussions over the two research strategies—their definitions respectively, their distinctions and their overlaps, it can be seen that each research strategy has their own merits and disadvantages. While doing social research, we shouldn‘t fall into the trap which many beginning researchers do in thinking that quantitative research is ―better‖ than qualitative research or vice versa. Neither is better than the other—they are just research methods and which one to choose during the research process should be based upon the topics of research and the purposes of doing the research. They are even compatible with each other in some research field. While doing social research, we need to view them with a justified attitude and to combine them together if necessary. To combine these two methods doesn‘t mean that researchers should subordinate their awareness that different approaches are supported by different epistemologies and ontological assumptions, which require their handling by different terminologies. Different strategies based on different methods should be combined for a higher and more different purpose than that associated with the respective and established approach. Competing theories are generally the product of different traditions, so when combined they may offer a fuller picture but not a more ―objective‖ one. Likewise, different methods draw on different (and often competing) epistemologies and while combining them researchers can add range and depth but not necessarily accuracy.ReferencesBryman, J. (2001) Social Research Methods. Oxford: Oxford University Press.Creswell, J. W (1994) Handbook of Mixed Methods Research in Social and Behavioral Research. London: Sage Publications: 209-223.Hammersley, M. (1996) ‗The relationship between qualitative and quantitative research: paradigm loyalty versus methodological eclecticism‘, in Richardson, J.T.E. (ed.) Handbook of Qualitative Research Methods for Psychology and the Social Sciences. Leics. British Psychological Society: 159-165.Fielding, N. and Schreier, M. (2001) ‗Introduction: On the Compatibility between Qualitative and Quantitative Research Methods‘, in FQS forum, V olume 2, No. 1, Art.4 – February.Johnson, R. B. and Onwuegbuzie, A. J. (2004) ‗Mixed methods research: a research paradigm whose time has come‘, Educational Researcher, 33 (7): 14-26.Walsham, G. (1995) ‗The emergence of interpretivism in IS research‘, Information Systems Research. Institute for Operations Research and the Management Sciences: 376-394.Shields, L. and Twycross, A. (2003) ‗The difference between quantitative research and qualitative research‘, Paediatric Nursing, 15: 24.Maxwell, J. A. (2005) Qualitative Research Design: An Interactive Approach. Sage Publictions: 22-28.LIANG Li-ping, (2004) ‗Quantitative Research and Qualitative Research: Difference and Adjustment of Research Methods in social Science‘, Social Sciences Journal of Colleges of Shanxi, 16: 25-28.周春燕，《质的研究还是量的研究——教育研究方法论的省思》，教育科学论坛，2006.嘎日达，《社会科学中质的研究与量的研究之争及其启示》，新视野，2006.。
新编简明英语语言学教程第2版学习指南答案Study Guide for New Concise English Linguistics Tutorial 2nd Edition AnswersIntroductionThe New Concise English Linguistics Tutorial 2nd Edition is a comprehensive guide to the study of the English language. This study guide provides answers to the exercises and questions found in the textbook, helping students to better understand the concepts and theories discussed in each chapter.Chapter 1: Introduction to Linguistics1.1 What is Linguistics?Linguistics is the scientific study of language and its structure, including phonology, morphology, syntax, semantics, and pragmatics.1.2 What are the subfields of Linguistics?The subfields of linguistics include phonetics, phonology, morphology, syntax, semantics, and pragmatics.1.3 What is the difference between prescriptive and descriptive grammar?Prescriptive grammar is concerned with rules for what is considered "correct" language use, while descriptive grammar describes how language is actually used by speakers.Chapter 2: Phonetics and Phonology2.1 What is phonetics?Phonetics is the study of the physical properties of speech sounds, including their production, transmission, and reception.2.2 What is phonology?Phonology is the study of the sound system of a language, including the patterns and rules that govern the pronunciation of words.2.3 What is the difference between consonants and vowels?Consonants are speech sounds that are produced with some degree of obstruction in the vocal tract, while vowels are speech sounds that are produced without obstruction.Chapter 3: Morphology3.1 What is morphology?Morphology is the study of the structure of words and how words are formed from smaller units called morphemes.3.2 What are free and bound morphemes?Free morphemes can stand alone as words, while bound morphemes must be attached to other morphemes to form a complete word.3.3 What is the difference between inflectional and derivational morphemes?Inflectional morphemes modify the grammatical function of a word (e.g., tense, number), while derivational morphemes create new words or change the meaning of existing words.Chapter 4: Syntax4.1 What is syntax?Syntax is the study of the structure of sentences and how words are combined to create meaningful phrases and sentences.4.2 What is the difference between phrases and clauses?Phrases are groups of words that function as a single unit within a sentence, while clauses are larger structures that contain a subject and a predicate.4.3 What is the difference between syntax and semantics?Syntax deals with the structure of language, while semantics is concerned with the meaning of language.Chapter 5: Semantics and Pragmatics5.1 What is semantics?Semantics is the study of meaning in language, including how words and sentences convey meaning.5.2 What is pragmatics?Pragmatics is the study of how context influences the interpretation of language, including the social and cultural factors that affect communication.5.3 What are speech acts?Speech acts are actions that are performed through speech, such as making a request or giving an order.ConclusionThis study guide provides answers to the exercises and questions found in the New Concise English Linguistics Tutorial 2nd Edition, helping students to deepen their understanding of the core concepts and theories in the study of English linguistics. By using this guide, students can enhance their knowledge andskills in the field of linguistics and improve their overall comprehension of the English language.。
Unit 1outcome结果statistics统计statistical 统计的toss投die骰子dice 掷骰子intuitive直觉的analogously类似的conceptually概念的simultaneous同时的collection集合identical同一的，同样的individual个别的ensemble集，总和ensemble average集平均variable变量random variable随机变量stationary平稳的ergodic个态历经的ergodic process各态历经过程deterministic确定性的normalize使标准化的normalized规格化的，归一化的expectation期望值product乘积truncate截断，截短periodic周期的covariance协方差uncorrelated不相关的uniform均匀的overlap部分重叠separation间隔，距离spacing间隔，间距random process随机过程on the average 平均，一般来说make measurement 量度sample function 样本函数statistical average 统计平均值probability density function概率密度函数statistical characteristic统计特征autocorrelation function 自相关函数in connection with 与，，有关physical significance物理意义Fourier transform傅里叶变换power spectral density 功率谱密度be at liberty to被允许gaussian process高斯过程physical fact外界存在的事实upper-frequency频率上限fall off下降in the limit在极限情况下delta function狄拉克函数random pulse随机脉冲time invariant时不变的parseval's theorem巴塞瓦尔定理statistically independent统计独立successive pulse连续脉冲be representative of表示，代表词组sample function样本函数ensemble average集合平均physical significance物理意义a fourier transform pair傅里叶变换对deterministic waveform 确定波形in the limit 在极限情况下time invariant时不变的an upper-frequency limit频率上限parseval，s theorem帕斯瓦尔定理random pulses随机脉冲随机过程random process统计平均statistical average随机变量random variable自相关函数autocorrelation function傅里叶变换fourier transform功率谱密度power spectral density概率密度函数probability density function 高斯过程gaussian process平稳过程stationary process统计独立statistically时间平均值time average统计特征statistical character各态历经过程ergodic processUnit 2abstraction抽象encompass包括devise设计whereby凭那个，由此arbitarily任意地theorem定理infrequent 罕见的override压倒thereby由此gaussian高斯的unity单一complementary补充的derivation推导formidable困难的undertake进行，从事presumed假定的presumably推测起来likelihood可能likely可能interval间隔rounding舍入，四舍五入abrupt，急剧的，不连续reliably可靠的，安全的heuristic启发式的intuitive直觉的intuitively直觉的contemplate预期的vice versa反之亦然quantize量化reception接受extreme极端的，偏激的attenuate衰减distort失真distortion失真equalizer均衡器recoverable可恢复的enter into参加，涉及due to 由于be something of 有一点in principle 原则上provided that假如on principle按照原则probability of error 误码率be close to接近bandlimited gaussian channel限带高斯信道physical system物理系统turn out结果lower bound下界upper limit 上限root-mean-square均方根root-mean-square error 均方误差amount of information 信息量ideal lowpass filter理想低通滤波器rise time上升时间as a matter of convenience为方便起见white gaussian noise 高斯白噪声on the other hand 另一面trade off交替换位tradeoff折中signal-to-noise ratio信号噪声比be free to 随意make up for 补偿词组physical system物理系统rise time 上升时间amount of information信息量in principle原则上gaussian channel高斯信道probability density概率密度root-mean-square均方根trade off折中lower bound下界equalizer均衡器vice versa反之亦然upper limit上限通信理论communication theory香农定理Shannon，s theorem信道带宽channel bandwidth信号波形signal waveform理想低通滤波器ideal lowpass filter自相关函数autocorrelation function无噪音高斯信道noiseless gaussian channel 通信信道communication channel信息速率information rate信噪比signal-to-noise ratio信道容量channel capacity双边功率谱密度two-side power误码率probability of error那奎斯特采样速率nyquist sampling rate限带高斯信道bandlimited gaussian channel 高斯白噪声White gaussian noiseUnit 3analog模拟quantization量化volt伏特discrete离散的quantum量unipolar单级的polar极性的on-off开关的encoding编码encoder编码器decoder解码器likewise同样的amplitude振幅margin余量trinary三倍的immune免疫的hereafter今后unavailable不能避免的reconstructed重建的evaluation计算span横跨interval间隔compandor压扩器companding压扩uniformly均匀的compress压缩compressor压缩器compressor ratio压缩比quantizer均匀量化器uniform quantizer均匀量化器equivalent相等的serially连续的reshape改造distortion失真interconnect使相互连接filter滤波transition转换，转变PCM: pulse code modulation脉冲编吗调制PAM: pulse amplitude modulation脉冲振幅调制PPM: pulse phase modulation 脉宽调制pulse train脉冲序列amount to等于round off舍入step size步长quantum step size 量化步长positive pulse 正脉冲refer to as称为quantization error 量化步长peak magnitude峰值overall performance总性能crest factor振幅因数root-mean-square均方根Differential Pulse Code Modulation 差分脉冲编码调制adaptive DPCM 自适应DPCMpredictive coding预测编码correspond to相应，符合in practice 实际中in an attempt to 力图词组overall performance总性能crest factor振幅因数nonlinear operation 非线性炒作inverse operation 逆运算RMS均方根PAM脉福调制maximum magnitude最大幅值error intervals误差间隔entropy墒round off四舍五入quantum level量化水平DPCM差分脉码调制正脉冲positive pulse脉冲编码调制PCM量化步长quantum step size 峰值peak magnitude线性函数linear function脉冲序列pulse train均匀量化器uniform quantizer 预测编码predictive coding 压扩器compandor压缩比compression ratio Unit 4selectively仔细挑选formula公式formulas公式化sacrifice牺牲redundant冗余的demonstrate证明orthogonal正交的arbitrarily任意地raw未加工的raw data 原始数据denote 指示Retransmission转发sophisticated复杂的impractical不切实际的parity奇偶校验encoder编码器codeword码字modulo以。
考研心理学专业名词中英文对照表（一)感觉记忆（SM）-sensory memory短期记忆（STM）—short—term M.长期记忆(LTM）—long—term memory复诵-—rehearsal预示（激发）--priming童年失忆症——childhood amnesia视觉编码（表征）-—visual code（representation）听觉编码—acoustic code运作记忆—-working memory语意性知识-semantic knowledge记忆扫瞄程序—memory scanning procedure竭尽式扫瞄程序—exhaustive S.P。
自我终止式扫瞄-self-terminated S。
程序性知识—procedural knowledge命题（陈述）性知识——propositional（declarative）knowledge 情节(轶事）性知识—episodic K。
讯息处理深度-depth of processing精致化处理-elaboration登录特殊性-coding specificity记忆术—mnemonic位置记忆法—method of loci字钩法—peg word（线)探索（测）（激发）字—prime关键词-—key word命题思考--propositional thought心像思考——imaginal thought行动思考——motoric thought概念—-concept原型-—prototype属性——property特征——feature范例策略——exemplar strategy语言相对性（假说）-linguistic relativity th。
音素——phoneme词素——morpheme(字词的）外延与内涵意义—denotative ＆connotative meaning （句子的）表层与深层结构-surface ＆deep structure语意分析法——semantic differential全句语言—holophrastic speech过度延伸——over—extension电报式语言—telegraphic speech关键期——critical period差异减缩法——difference reduction方法目的分析——means-ends analysis倒推——working backward动机——motive自由意志——free will决定论——determinism本能-—instinct种属特有行为——species specific驱力——drive诱因-—incentive驱力减低说——drive reduction th.恒定状态（作用）—homeostasis原级与次级动机-primary & secondary M。
thesis的英文名词解释Thesis: Unveiling the Epitome of Academic InquiryIntroductionIn the realm of academia, the term "thesis" holds an esteemed position, symbolizing the culmination of scholarly rigor, in-depth research, and critical analysis. Universally acknowledged as a prerequisite for the successful completion of undergraduate, postgraduate, and doctoral degrees, the thesis represents the pinnacle of academic achievement. This article delves into the various dimensions of the thesis, shedding light on its multifaceted nature and emphasizing its significance within the academic community.1. Defining the ThesisAt its core, a thesis is an extended written discourse that serves as a comprehensive exploration of a specific research question or hypothesis. It embodies the culmination of a student's academic journey, allowing individuals to showcase their mastery of a subject matter within a particular field of study. A thesis encompasses numerous elements, such as literature review, methodology, data analysis, and conclusion; often accompanied by substantiating evidence and scholarly references.2. Research and AnalysisThe research process is the foundation upon which a thesis is built. Students engage in an extensive literature review, scouring academic databases, journals, and books to identify gaps in knowledge and contribute novel insights to the chosen field. With gathered information, researchers employ critical and analytical thinking skills to examine the existing body of knowledge and formulate research questions. These questions guide the data collection process, helping to refine and answer the central thesis question.3. Data Collection and Analysis TechniquesThe chosen methodology determines the data collection techniques employed within a thesis. Whether quantitative, qualitative, or a combination of both, researchers adopt methodologies that best suit their research aims and objectives. Surveys, interviews, experiments, observations, and content analysis are just a few examples of the strategies employed to acquire pertinent data. Thorough data analysis techniques, such as statistical analysis or thematic coding, allow for the identification of trends, patterns, and correlations, enabling researchers to draw meaningful inferences and conclusions.4. Structure and OrganizationA well-crafted thesis adheres to a logical structure and organization, facilitating the reader's comprehension and engagement. Typically, a thesis comprises the following sections: introduction, literature review, methodology, results/findings, discussion, and conclusion. Each section serves a distinct purpose, guiding the reader through a coherent and systematic exploration of the research question. Furthermore, within each section, clear and concise subheadings help delineate the flow of ideas and arguments, ensuring clarity and coherence.5. Intellectual Contribution and OriginalityOne of the primary objectives of a thesis is to provide an intellectual contribution to the chosen field of study. Students are encouraged to identify gaps in existing knowledge and devise novel approaches to solving complex problems. Originality, creativity, and critical thinking are highly valued, as students are expected to go beyond mere regurgitation of established theories and instead present fresh perspectives and innovative ideas. By doing so, students contribute to the expanding body of knowledge in their respective fields.6. Demonstrating Proficiency in Academic WritingAn important aspect of a thesis is the demonstration of proficiency in academic writing. Students are expected to uphold high standards of scholarly writing by employing appropriate language, adhering to referencing conventions, and demonstrating clarity of thought. An effective thesis showcases the ability to communicate complexconcepts and findings concisely, engaging the reader and conveying the essence of the research.ConclusionThe thesis represents a significant milestone in one's academic journey, encapsulating the challenging endeavor of conducting extensive research, analyzing data, and making original contributions to a given field of study. It embodies the culmination of years of academic training, critical thinking, and intellectual exploration. The thesis goes beyond being a mere requirement for academic degrees; rather, it stands as a testament to an individual's determination, knowledge acquisition, and passion for knowledge dissemination.。
J.Agric.Food Chem.2009,57,7919–79237919DOI:10.1021/jf9020812 Semisynthesis and Quantitative Structure-ActivityRelationship(QSAR)Study of Novel Aromatic Esters of40-Demethyl-4-deoxypodophyllotoxin as Insecticidal AgentsH UI X U,*,†J UANJUAN W ANG,†H UIJUN S UN,§M IN L V,†X UAN T IAN,§X IAOJUN Y AO,*,§AND X ING Z HANG††Laboratory of Pharmaceutical Design and Synthesis,College of Life Sciences,Northwest A&FUniversity,22Xinong Road,Yangling712100,Shannxi Province,People’s Republic of China,and§Department of Chemistry,Lanzhou University,Gansu Province,People’s Republic of ChinaBy using podophyllotoxin as a phytoinsecticidal lead compound,15novel aromatic esters of40-demethyl-4-deoxypodophyllotoxin were semisynthesized and preliminarily tested for their insecticidalactivity against the pre-third-instar larvae of Mythimna separata Walker in vivo for the first time.Among all of the tested compounds,especially two compounds,4m and4o,containing a pyridinylgroup,for which final corrected mortality rates against M.separata at1mg/mL were62.9and59.2%,respectively,showed the most promising and pronounced insecticidal activity as comparedwith toosendanin,a commercial insecticide derived from Melia azedarach.The quantitative struc-ture-activity relationships(QSAR)of compounds4a-4o showed that the relative number ofbenzene rings and final heat of formation were very important descriptors to their insecticidalactivity.KEYWORDS:Podophyllotoxin;synthesis;insecticidal activity;structure-activity relationshipINTRODUCTIONIn the course of our screening for novel naturally occurring phytoinsecticides from the plants in northwestern China,podo-phyllotoxin(1)(Figure1)was isolated as an insecticidal compo-nent by bioassay-guided fractionation from Juniperus sabina Linnaeus(1).It is well-known that structural modification is an effective method to optimize natural bioactive compounds. Recently,to obtain more potent insecticidal podophyllotoxin analogues,compound1has been used as a lead compound for structural modification,and some derivatives exhibited more potent insecticidal activity than1against the larvae of Drosophila melanogaster Meigen,Pieris rapae Linnaeus,or Mythimna separata Walker in vivo(2-6).Obviously,the recent structural modification of1as an insecticidal agent has been mainly focused on the C-4position of1.To the best of our knowledge,however, little attention has been paid to structural modification on the C-40position of1.In continuation of our program aimed at the discovery and development of bioactive molecules(3-7),we want to investigate the effect of substituents on the C-40position of podophyllotoxin analogues to the insecticidal activity.In the meantime,You et al.reported that some alkyl and carboxylalkyl esters of40-demethyl-4-deoxypodophyllotoxin exhibited good antitumor activity(8).Therefore,in this paper15novel aromatic esters of40-demethyl-4-deoxypodophyllotoxin(4a-4o)were semisynthesized from1and tested for their insecticidal activity against pre-third-instar larvae of M.separata Walker in vivo for the first time.The quantitative structure-activity relationships (QSAR)of these compounds were also studied.MATERIALS AND METHODSSynthetic Procedures.Podophyllotoxin was purchased from Gansu Gerui Medicinal Materials Co.,Ltd.All reagents and solvents were of reagent grade or purified according to standard methods before use. Analytical thin-layer chromatography(TLC)and preparative thin-layer chromatography(PTLC)were performed with silica gel plates using silica gel60GF254(Qingdao Haiyang Chemical Co.,Ltd.).Melting points were determined on a digital melting-point apparatus and were uncorrected. Infrared spectra(IR)were recorded on a Thermo Nicolet Nexus FTIR-8700spectrometer.Proton nuclear magnetic resonance spectra(1H NMR) were recorded on a Bruker Avance DMX400MHz instrument using TMS as internal standard and CDCl3as solvent.High-resolution mass spectra (HR-MS)and electron ionization mass spectrometry(EI-MS)or electro-spray iontrap mass spectrometry(ESI-TRAP-MS)were carried out with APEX II Bruker4.7T AS and Thermo DSQ GC-MS or Bruker ESI-TRAP Esquire3000plus mass spectrometry instruments,respectively. 4-Deoxypodophyllotoxin(2).A mixture of10%palladium/carbon (12.0g)and podophyllotoxin(1,16.0g,38.6mmol)in acetic acid solution (150mL)was stirred at95°C under2atm of hydrogen for5h.After filtration to remove the catalyst and evaporation of the solvent,the residue was purified by silica gel column chromatography(diethyl ether/dichloro-methane,6:1)to give the crude product,which was further purified by recrystallization from methanol to afford9.8g(66%)of2as a white solid: mp165-167°C[lit.,166-168°C(9)];[R]20D=-116°(c1mg/mL,CHCl3); IR cm-12892,2831,1763,1587,1482,1457,1223,1120,925,768;1H NMR(400MHz,CDCl3)δ6.67(s,1H,H-5),6.52(s,1H,H-8),6.34(s,2H, H-20,60),5.93(d,J=8.0Hz,2H,OCH2O),4.60(s,1H,H-1),4.43(m,1H,*Author to whom correspondence should be addressed[(H.X.)telephoneþ86(0)29-87091952;faxþ86(0)29-87091952;e-mail orgxuhui@.(X.Y.)e-mail xjyao@]./JAFCPublished on Web08/18/2009©2009American Chemical Society7920J.Agric.Food Chem.,Vol.57,No.17,2009Xu et al.H-11),3.89(m,1H,H-11),3.79(s,3H,40-OCH3),3.75(s,6H,30,50-OCH3), 3.06(m,1H,H-4),2.71(m,3H,H-2,3,4);MS(EI),m/z(%)398.1 (Mþ,100).40-Demethyl-4-deoxypodophyllotoxin(3).2(2g,50.2mmol)was suspended in1,2-dichloroethane(25mL)and diethyl ether(2.5mL)at 0°C.A flow of dry hydrobromic acid was passed in the above solution. When the reaction was complete according to TLC analysis,water (25mL),acetone(25mL),and a little amount of BaCO3were added to the reaction mixture,which continued to stir for0.5h and extracted by EtOAc(30mLÂ4).Subsequently,the combined organic phase was washed by brine(50mLÂ2),dried over anhydrous Na2SO4,filtered, concentrated in vacuo,and purified by silica gel column chromatography (chloroform/ethyl acetate,5:1)to give1.16g(60%)of3as a khaki solid: mp246-248°C[lit.,244-249°C(10)];[R]20D=-130°(c0.4mg/mL, CHCl3);IR cm-12899,2824,1757,1608,1478,1458,1214,1105,922,769; 1H NMR(400MHz,CDCl3)δ6.66(s,1H,H-5),6.51(s,1H,H-8),6.35(s, 2H,H-20,60),5.92(m,2H,OCH2O),5.39(s,1H,40-OH),4.59(d,J=2.4Hz, 1H,H-1),4.42(m,1H,H-11),3.88(m,1H,H-11),3.78(s,6H,30,50-OCH3), 3.05(m,1H,H-4),2.71(m,3H,H-2,3,4);MS(EI),m/z(%)383.9 (Mþ,100).General Synthetic Procedure for Aromatic Esters of40-De-methyl-4-deoxypodophyllotoxin(4a-4o).A mixture of the corre-sponding acid(0.3mmol),diisopropylcarbodiimide(DIC,0.3mmol),4-dimethylaminopyridine(DMAP,0.1mmol),and3(0.25mmol)in dried dichloromethane(10mL)was stirred at0°C.When the reaction was complete according to TLC analysis,the resulting suspension was filtered, and water(25mL)was added to the solution of the above mixture,which was extracted with dichloromethane(30mLÂ4).Then the organic phase were combined,dried over anhydrous Na2SO4,concentrated in vacuo,and purified by PTLC to give the pure target products in38-93%yields.The example data of4a and4b are shown as follows,whereas data for4c-4o can be found in the Supporting Information.Data for4a:R f=0.52(petroleum ether/ethyl acetate,1:1);yield=93%; white solid,mp223-225°C;[R]20D=-79°(c0.29mg/mL,CHCl3);IR cm-12921,2849,1779,1759,1597,1482,1459,1224,1122,928,774,731; 1H NMR(400MHz,CDCl3)δ7.38(d,J=7.2Hz,2H,H-200,600),7.32(m, 2H,H-300,500),7.28(d,J=7.6Hz,1H,H-400),6.65(s,1H,H-5),6.51(s,1H, H-8),6.35(s,2H,H-20,60),5.92(dd,J=1.2Hz,J=8.0Hz,2H,OCH2O), 4.61(d,J=4.4Hz,1H,H-1),4.42(m,1H,H-11),3.88(m,3H,H-11and CH2C6H5),3.62(s,6H,30,50-OCH3),3.03(m,1H,H-4),2.69(m,3H,H-2, MS(ESI-TRAP),m/z(%)525([MþNa]þ,25).HRMS:Anal.Calcd for C29H30NO8([MþNH4]þ),520.1966;found,520.1960.Data for4b:R f=0.7(dichloromethane/acetone,50:1);yield=71%; white solid,mp256-258°C;[R]20D=-80°(c0.26mg/mL,CHCl3);IR cm-12921,2849,1761,1738,1597,1486,1454,1230,1128,928,771,706; 1H NMR(400MHz,CDCl3)δ8.19(d,J=7.6Hz,2H,H-200,600),7.59(t,J= 7.6Hz,1H,H-400),7.46(t,J=7.6Hz,2H,H-300,500),6.68(s,1H,H-5),6.59 (s,1H,H-8),6.43(s,2H,H-20,60),5.94(d,J=7.6Hz,2H,OCH2O),4.67(s, 1H,H-1),4.46(m,1H,H-11),3.89(m,1H,H-11),3.69(s,6H,30,50-OCH3), 3.07(m,1H,H-4),2.76(m,3H,H-2,3,4);MS(ESI-TRAP),m/z(%)511([MþNa]þ,39).HRMS:Anal.Calcd for C28H28NO8([MþNH4]þ), 506.1809;found,506.1802.Biological Assay.The insecticidal activity of4a-4o against the pre-third-instar larvae of M.separata Walker was assessed by leaf-dipping method as described previously(5).For each compound,30larvae (10larvae per group)were used.Acetone solutions of4a-4o and toosendanin(used as a positive control)were prepared at the concentra-tion of1mg/mL.Fresh corn leaves were dipped into the corresponding solution for3s,then taken out,and dried in a room.Leaves treated with acetone alone were used as a control group.Several treated leaves were kept in each dish,where every10larvae were raised.If the treated leaves were consumed,corresponding ones were added to the dish.After48h, untreated fresh leaves were added to all dishes until the adult emergence. The experiment was carried out at25(2°C and relative humidity(RH) 65-80%on a12h/12h(light/dark)photoperiod.The insecticidal activity of the tested compounds against the pre-third-instar larvae of M.separata was calculated by the formulacorrected mortality rateð%Þ¼ðT-CÞÂ100=ð1-CÞwhere T is the mortality rate in the treated group expressed as a percentage and C is the mortality rate in the untreated group expressed as a percentage.RESULTS AND DISCUSSIONSynthesis.As shown in Scheme1,4-deoxypodophyllotoxin(2) was first obtained in a66%yield by catalytic hydrogenolysis of1 in the presence of10%palladium/carbon(9).Then regioselective 40-demethylation of2with dry hydrobromide,followed by the mixed solvent system(water/acetone)and BaCO3,could proceed readily to give the40-demethyl-4-deoxypodophyllotoxin(3)in a 60%yield(10).Finally,15esters of40-demethyl-4-deoxypodo-phyllotoxin(4a-4o)were obtained by the reaction of3with the corresponding acids containing aromatic cycles in the presence of DIC and DMAP.The structures of the target compounds were well characterized by1H NMR,HRMS,MS,optical rotation, and IR.Biological Activity.The insecticidal activity of4a-4o against the pre-third-instar larvae of M.separata Walker in vivo was investigated by the leaf-dipping method at the concentration of 1mg/mL.Toosendanin,a commercial insecticide derived from M.azedarach,was used as a positive control.As shown in Table1, the corresponding corrected mortality rates caused by these compounds after36days were far higher than those after12 and24days.For example,the corrected mortality rate of4m against M.separata after12days was only3.5%;after24days, the corresponding mortality rate was increased to10.7%,but after36days the corresponding mortality rate was sharplyScheme1Article J.Agric.Food Chem.,Vol.57,No.17,20097921increased to62.9%,which was nearly18times the mortality rate after12days.That is,these compounds showed delayed insecti-cidal activity(5),which is different from the conventional neurotoxic insecticides,such as organophosphates,carbamates, and pyrethroids.Meanwhile,the symptoms of the tested M.separata were also characterized as the same as our previous reports(5).Additionally,the pupation of the larvae and the adult emergence of M.separata were inhibited by these compounds; therefore,the stage from the larvae to adulthood of M.separata was prolonged as compared to the control group.Moreover, many larvae of the treated groups were unable to reach adulthood and died during the stage of pupation.Among all of the testedTable1.Insecticidal Activity of Novel Aromatic Esters of40-Demethyl-4-deoxypodophyllotoxin(4a-4o)against Mythimna separata Walker inVivo7922J.Agric.Food Chem.,Vol.57,No.17,2009Xu et al. compounds,especially compounds4m and4o containing apyridinyl group,for which corrected mortality rates againstM.separata after36days were62.9and59.2%,respectively,exhi-bited the most promising and best insecticidal activity as com-pared to toosendanin(40.7%).Qualitative Structure-Activity Relationships(SAR).As shownin Table1,when the methyl group was introduced at the metaposition on the phenyl ring of4b to give4d,the insecticidalactivity of4d was more potent than the one having a p-methylgroup on the phenyl ring of4b(4d vs4c).The same results werealso found for compounds4i and4j;for example,when the nitrogroup was introduced at the meta position on the phenyl ring of4b to give4i,the insecticidal activity after36days of4i wasincreased as compared with4b(48.1%for4b and51.8%for4i).However,when the nitro group was introduced at the paraposition on the phenyl ring of4b to give4j,the insecticidalactivity after36days of4j was decreased as compared with4b(48.1%for4b and40.7%for4j).Interestingly,if two nitro groupswere stimultaneously introduced at the meta position on thephenyl ring of4b to give4k,the insecticidal activity after36daysof4k was decreased sharply as compared with4b(48.1%for4band22.2%for4k);that is,4k exhibited>2-fold less potencythan4b.Moreover,introducing one electron-withdrawing group(e.g.,nitro group)on the phenyl ring of4b will usually give moreactive compounds than the one having an electron-donatinggroup(e.g.,methyl,methoxy,and chloro)on the phenyl ring of4b(4i and4j vs4c-4g).It was noteworthy that especially whenthe pyridinyl ring was substituted for the phenyl ring of4b,thecorrected mortality rates after36days of the correspondingcompounds4m and4o were increased to62.9and59.2%,respectively.Therefore,some aromatic esters of40-demethyl-4-deoxypodophyllotoxin containing other heterocyclic rings will besynthesized and studied in our laboratory.Quantitative Structure-Activity Relationships(QSAR).Thestructures of15molecules4a-4o were drawn by using Sybyl 6.9(11).All structures were preoptimized by the molecular mechanics force field(MMþ)(12)and then optimized using the semiempirical method PM3implemented in Hyperchem and MOPAC(13).Comprehensive Descriptors for Structural and Statistical Analysis(CODESSA)is a comprehensive program for develop-ing quantitative structure-activity/property relationships(QS-AR/QSPR)by integrating all necessary mathematical and com-putational tools.The output files from MOPAC were used by the CODESSA program to calculate molecular descriptors(14).The Best Multilinear Regression method(BMLR)was used to select the significant descriptors and develop the QSAR model.Four hundred and seventy-three descriptors were calculated for each molecule.After using the BMLR method,three descriptors correlated with the final corrected mortality rate(%)were selected for the1540-demethyl-4-deoxypodophyllotoxin deriva-tives4a-4o.The BMLR model and its statistical parameters are shown in Table2.This model gave a squared correlation coefficient(R2)of0.868,a squared standard deviation(s2)of 23.543,and a cross-validated squared correlation coefficient (R2cv)of0.749.Detailed information about the predicted corrected mortality rate,the experimental corrected mortality rate,the errors,and the values of the selected descriptors are given in Table3.The three selected descriptors belonged to constitutional and quantum-chemical descriptors.They were relative number of benzene rings,final heat of formation,and RNCS relative negative charged SA(SAMNEG*RNCG)[quantum-chemical PC].According to the t test value,the relative number of benzene rings and final heat of formation were very important descriptors.A negative coefficient before the relative number of benzene rings in this model indicated that an increase of this value led to a decrease in the mortality rate of the compounds due to the reduction in the solubility of the compound.The final heat of formation was proportionally interrelated with the Gibbs free energy.The plot of the predicted corrected mortality rate of the compounds versus their experimental values is shown in Figure2. In conclusion,15novel aromatic esters of40-demethyl-4-deox-ypodophyllotoxin4a-4o were semisynthesized and tested for their insecticidal activity against pre-third-instar larvae of M.separata in vivo at the concentration of1mg/mL.Among all of the tested compounds,especially compounds4m and4o showed the most promising and best insecticidal activity as compared to toosendanin.Table2.BMLR Model and Its Statistical Parametersdescriptor X a DX b t test value c intercept 1.9193Â102 2.3448Â1018.1853 relative number of benzene rings-1.2144Â103 2.2330Â102-5.4385final heat of formation 6.4032Â10-1 1.1081Â10-1 5.7785 RNCS relative negative charged SA(SAMNEG*RNCG)[quantum-chemical PC] 1.1577Â101 2.5599Â10 4.5225 a X,regression coefficient of the descriptor.b DX,standard errors of the regression coefficient X.c t test value,t statistics of the regression coefficient X.rmation of Predicted Corrected Mortality Rate,ExperimentalCorrected Mortality Rate,Errors,and Detail Information of the SelectedDescriptorsselected descriptorsno.exptl(%)pred(%)error(%)D1a D2b D3c4a29.631.1 1.50.0476-217.089 3.10804b48.144.7-3.40.0500-208.910 4.07934c33.339.6 6.30.0476-218.458 3.91824d40.741.40.70.0476-218.454 4.07214e25.927.4 1.50.0469-247.513 4.39254f37.033.2-3.80.0500-213.294 3.32964g29.628.9-0.70.0500-215.347 3.07554h37.036.1-0.90.0580-199.103 3.63534i51.845.7-6.10.0484-217.155 4.45264j40.735.6-5.10.0484-218.012 3.62894k22.226.7 4.50.0469-220.094 2.81804l48.156.98.80.0469-197.082 4.15594m62.958.0-4.90.0339-201.476 3.13364n40.741.40.70.0411-209.582 2.89624o59.260.3 1.10.0339-201.747 3.3438a D1,relative number of benzene rings.b D2,final heat of formation.c D3,RNCSrelative negative charged SA(SAMNEG*RNCG)[quantum-chemical PC].Article J.Agric.Food Chem.,Vol.57,No.17,20097923QSAR of compounds4a-4o found that the relative number of benzene rings and final heat of formation were very important descriptors for their insecticidal activity.Supporting Information Available:1H NMR,HRMS,MS, optical rotation,melting point,and IR data for the target com-pounds.This material is available free of charge via the Internet at .LITERATURE CITED(1)Wang,J.D.;Tian,X.;Zhang,X.The isolation and identification ofpodophyllotoxin from Sabina vulgaris Ant.Acta Univ.Agric.Bor-eali-Occidentalis2000,28,25–29.(2)Miyazawa,M.;Fukuyama,M.;Yoshio,K.;Kato,T.;Ishikawa,Y.Biologically active components against Drosophila melanogaster from Podophyllum hexandrum.J.Agric.Food Chem.1999,47, 5108–5110.(3)Di,X.D.;Liu,Y.Q.;Liu,Y.Q.;Yu,X.Y.;Xiao,H.;Tian,X.;Gao,R.Synthesis and insecticidal activities of pyridine ring derivatives of podophyllotoxin.Pestic.Biochem.Physiol.2007,89,81–87.(4)Liu,Y.Q.;Yang,L.;Liu,Y.Q.;Di,X.D.;Xiao,H.;Tian,X.;Gao,R.Synthesis and insecticidal activities of novel derivatives of podophyllotoxin.Nat.Prod.Res.2007,21,967–974.(5)Xu,H.;Zhang,X.;Tian,X.;Lu,M.;Wang,Y.G.Synthesis andinsecticidal activity of novel4β-halogenated benzoylamino podo-phyllotoxins against Pieris rapae Linnaeus.Chem.Pharm.Bull.2002, 50,399–402.(6)Xu,H.;Zhang,L.;Su,B.F.;Zhang,X.;Tian,X.Natural products-based insecticidal agents1.Semisynthesis and insecticidal activity of 4β-benzenesulfonamide derivatives of podophyllotoxin against Mythimna separata Walker.Heterocycles2009,77,293–300. (7)Xu,H.;Lv,M.;Tian,X.A review on hemisynthesis,biosynthesis,biological activities,mode of action,and structure-activity relation-ship of podophyllotoxins:2003-2007.Curr.Med.Chem.2009,16, 327–349.(8)You,Y.;Kim,Y.;Nam,N.;Bang,S.;Ahn,B.Alkyl and carboxyl-alkyl esters of40-demethyl-4-deoxypodophyllotoxin:synthesis,cyto-toxic,and antitumor activity.Eur.J.Med.Chem.2004,39,189–193.(9)Gensler,W.J.;Judge,J.F.X.;Leeding,M.V.2-Carboxydeoxy-.Chem.1972,37,1062–1064.(10)Kuhn,M.;Keller-Juslen,G.;von Wartburg,A.Partialsynthese von40-demethylepipodophyllotoxin.Helv.Chim.Acta1969,52,944–947.(11)Sybyl6.9;Tripos Associates:St.Louis,MO,1999.(12)HyperChem7.0;Hypercube:Gainesville,FL,2002.(13)Stewart,J.P.P.MOPAC6.0;Quantum Chemistry Program Exchange,QCPE;Indiana University:Bloomington,IN,1989;Vol.455.(14)Katritzky,A.R.;Lobanov,V.S.;Karelson,M.CODESSA Version2.0Reference Manual;Semichem:Shawnee,KS,1995-1997.Received June19,2009.Revised manuscript received July29,2009. Accepted July30,2009.This work was supported by the program for New Century Excellent University Talents,State Education Ministry of China(NCET-06-0868),the Key Project of Chinese Ministry of Education(No.107105),and the Research Fund for the Doctoral Program of Higher Education of China(No.20070712025).。
