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91.
Norman PJ Abi-Rached L Gendzekhadze K Korbel D Gleimer M Rowley D Bruno D Carrington CV Chandanayingyong D Chang YH Crespí C Saruhan-Direskeneli G Fraser PA Hameed K Kamkamidze G Koram KA Layrisse Z Matamoros N Milà J Park MH Pitchappan RM Ramdath DD Shiau MY Stephens HA Struik S Verity DH Vaughan RW Tyan D Davis RW Riley EM Ronaghi M Parham P 《Nature genetics》2007,39(9):1092-1099
Interactions of killer cell immunoglobulin-like receptors (KIRs) with major histocompatibility complex (MHC) class I ligands diversify natural killer cell responses to infection. By analyzing sequence variation in diverse human populations, we show that the KIR3DL1/S1 locus encodes two lineages of polymorphic inhibitory KIR3DL1 allotypes that recognize Bw4 epitopes of protein">HLA-A and HLA-B and one lineage of conserved activating KIR3DS1 allotypes, also implicated in Bw4 recognition. Balancing selection has maintained these three lineages for over 3 million years. Variation was selected at D1 and D2 domain residues that contact HLA class I and at two sites on D0, the domain that enhances the binding of KIR3D to HLA class I. HLA-B variants that gained Bw4 through interallelic microconversion are also products of selection. A worldwide comparison uncovers unusual KIR3DL1/S1 evolution in modern sub-Saharan Africans. Balancing selection is weak and confined to D0, KIR3DS1 is rare and KIR3DL1 allotypes with similar binding sites predominate. Natural killer cells express the dominant KIR3DL1 at a high frequency and with high surface density, providing strong responses to cells perturbed in Bw4 expression. 相似文献
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93.
In contemplating better ways to manage, Stafford Beer says the big problem is that you are not determining absolute facts: you are establishing a set of conventions. Hence his view, that a model is neither true nor false: it is more or less useful. And while this paper suggests Beer’s Viable Systems Model (VSM) is overwhelmingly more, rather than less useful, that the VSM and its founding theories are virtually unknown at the level of everyday management begs the question, why? Over time we have learned about the usefulness of the VSM compared to other management theories, when used in the contest of the organisational strategic planning process. Thus through a sequence of diagrams based on Beer’s original drawings, we show how the VSM came to underpin a process for strategic planning in one organisation. The paper has three aims; to attach an everyday ‘common speak’ understanding to some of Beer’s work, to demonstrate how we have learned to appreciate the usefulness of the VSM and its associated diagrams and conventions and to suggest a link between the Action Research change methodology and Beer’s work. 相似文献
94.
Lester D. Stephens 《Annals of science》2013,70(3):303-321
The nineteenth-century American scientist, philosopher and teacher Joseph LeConte (1823–1901) is well-known for his writings on geology and the reconciliation of evolutionary theory and religion, but he has not been properly recognized for his contributions to the physiology and psychology of vision. This study explores and assesses his work in the latter field, showing the nature of his original investigations into human vision and the influence of his book Sight: an exposition of the principles of monocular and binocular vision, which served as the major textbook on the subject in the United States from its publication in 1881 until after the turn of the century. Grounded in neo-Lamarckian evolutionary theory, LeConte's publications on vision had a strong impact upon subsequent studies of the phenomenon of human sight. 相似文献
95.
Albers CA Paul DS Schulze H Freson K Stephens JC Smethurst PA Jolley JD Cvejic A Kostadima M Bertone P Breuning MH Debili N Deloukas P Favier R Fiedler J Hobbs CM Huang N Hurles ME Kiddle G Krapels I Nurden P Ruivenkamp CA Sambrook JG Smith K Stemple DL Strauss G Thys C van Geet C Newbury-Ecob R Ouwehand WH Ghevaert C 《Nature genetics》2012,44(4):435-9, S1-2
96.
噬菌体作为细菌病毒,在细菌性感染尤其是多重耐药菌感染的治疗方面具有抗生素无法比拟的优势。目前人工改造噬菌体的理论和技术已趋成熟,研究者通过基因工程技术解决了噬菌体特异性高、半衰期短、释放内毒素等问题,使基因工程改造噬菌体具有了较强的临床应用潜力。本文主要就基因工程改造噬菌体在扩大宿主范围、增强抗生素疗效、延缓免疫清除、避免内毒素释放等方面所具有的优势,及其在剂量确定、细菌耐受、宿主安全性等方面可能会出现的问题进行了阐述。 相似文献
97.
Anne Stephens Chris Jacobson Christine King 《Systemic Practice and Action Research》2010,23(5):371-386
This paper provides the findings of a study to locate the similarity and/or differences between two epistemologies: critical systems thinking and cultural ecofeminism. Selected texts from authors in each field were coded and compared using the Constant comparative analysis, grounded theory method. The analysis revealed a multitude of similarities across a range of concepts, including systems thinking language; challenges to positivist science, reason and instrumentalism; ethics and morality and praxis. The analysis also revealed several emergent principles for working towards a feminist systems theory of practice. 相似文献
98.
Anne Stephens 《Systemic Practice and Action Research》2014,27(4):309-323
The purpose of this article is to describe the use of systemic intervention research methodology at an Indigenous-specific Australian drug and alcohol ‘therapeutic community’ rehabilitation setting. Systemic intervention is a three step methodological framework belonging to the systems thinking discipline. Practitioners must be mindful of the boundaries of the systems with which they are working; the need to select appropriate theoretical and methodological approaches to the context of the research, and undertake interventions towards sustainable and desirable change. Three participatory methods are detailed to highlight the importance and value of reflective practice. The three methods ranged from consultative through to collegial levels of participant engagement. Systemic intervention is a useful methodology in the context of indigenous health research and could be a valued approach in other research contexts that are explicit in their intent to help close the gap on Indigenous health disadvantage. 相似文献
99.
100.
通过比较容许应力设计法(ASD)与载荷抗力系数设计法(LRFD)来分析构件稳定,以达到钢斜拉桥主要受力构件设计节省和经济的原则.用ASD理论和LRFD理论中的轴向弯曲交互方程来检验钢斜拉桥主要构件的稳定性.计算梁和塔柱交叉点的交互方程的数值,通过计算的数值统计分析二者谁更节省以及节省的幅度,从而为梁和塔柱的设计提供指导.同时,分别运用ANSYS有限元程序进行特征值屈曲分析和非线性屈曲分析,比较二者确定的屈曲载荷,为稳定设计提供相关的参考和依据. 相似文献