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1.
To uncover the molecular composition and dynamics of the functional scaffold for the nucleus, three fractions of biochemically-stable nuclear protein complexes were extracted and used as immunogens to produce a variety of monoclonal antibodies. Many helix-based cytoskeletal proteins were identified as antigens, suggesting their dynamic contribution to nuclear architecture and function. Interestingly, sets of antibodies distinguished distinct subcellular localization of a single isoform of certain cytoskeletal proteins; distinct molecular forms of keratin and actinin were found in the nucleus. Their nuclear shuttling properties were verified by the apparent nuclear accumulations under inhibition of CRM1-dependent nuclear export. Nuclear keratins do not take an obvious filamentous structure, as was revealed by non-filamentous cytoplasmic keratin-specific monoclonal antibody. These results suggest the distinct roles of the helix-based cytoskeletal proteins in the nucleus.  相似文献   

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<正>在自然界中,令所有动物朝思暮想的莫过于两个字——食物,它们费尽心思地找寻它、抢夺它,甚至会为了它而大动干戈。和动物们共同生活在地球上的植物看上去安静而又文气,似乎和动物们不会发生什么冲突,可是有时候,这二位偏偏会瞄上相同的食物……  相似文献   

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In recent years, discourses around “personalized,” “stratified,” and “precision” medicine have proliferated. These concepts broadly refer to the translational potential carried by new data-intensive biomedical research modes. Each describes expectations about the future of medicine and healthcare that data-intensive innovation promises to bring forth. The definitions and uses of the concepts are, however, plural, contested and characterized by diverse ideas about the kinds of futures that are desired and desirable. In this paper, we unpack key disputes around the “personalized,” “stratified,” and “precision” terms, and map the epistemic, political and economic contexts that structure them as well as the different roles attributed to patients and citizens in competing future imaginaries. We show the ethical and value baggage embedded within the promises that are manufactured through terminological choices and argue that the context and future-oriented nature of these choices helps to understanding how data-intensive biomedical innovations are made socially meaningful.  相似文献   

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Summary It is well known that interactions among relatives facilitate the evolution of altruistic behaviours. Game theoretic models show, however, that guarded altruism (such as Tit-For-Tat) can evolve among non-relatives when individuals interact many times and cheating behaviours can be punished. Strangely, no one has yet asked whether the guarded altruism that evolves among non-relatives might also evolve among close relatives, supplanting unconditional altriusm. We present a series of one-locus sexual haploid models in which Tit-For-Tat, unconditional altruists and selfish individuals interact in groups of full siblings. Tit-For-Tat frequently (but not always) replaced unguarded altruism, in which case the strategic rules for interacting with kin vs non-kin are identical. Even when Tit-For-Tat is selected at a single locus, however, by withholding altruism for non-reciprocating relatives it may qualify as an outlaw from the standpoint of modifier genes at other loci.  相似文献   

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在举国上下热烈欢庆两个伟大胜利及第二次全国农业学大寨会议精神鼓舞下,亿万军民,群情振奋,大歌大颂华主席的英明领导,大揭大批“四人帮”的滔天罪行,形势大好,人心大快,我作为值保战线的一兵,心情更是激动。  相似文献   

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By elaborating upon the idea of “relational assimilation”, Tomas Jimenez alters the dominant lens through which social scientists, and especially sociologists, have understood the concept of assimilation and the effects of immigration. In this highly readable and thoughtful book, we are asked to conceive of this kind of assimilation as one which involves “the give-and-take of adjustment”, not just a one-way route by which “newcomers” must adapt to settings populated by “established” members of the population. According to the author, ongoing forms of immigration and its resulting diversity actually change the regional self-understandings of those who are already living in those settings.  相似文献   

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《BMJ (Clinical research ed.)》1951,2(4739):1074-1076
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Linking human health risk to environmental factors can be a challenge for clinicians, public health departments, and environmental health researchers. While it is possible that nonhuman animal species could help identify and mitigate such linkages, the fields of animal and human health remain far apart, and the prevailing human health attitude toward disease events in animals is an “us vs. them” paradigm that considers the degree of threat that animals themselves pose to humans. An alternative would be the development of the concepts of animals as models for environmentally induced disease, as well as potential “sentinels” providing early warning of both noninfectious and infectious hazards in the environment. For such concepts to truly develop, critical knowledge gaps need to be addressed using a “shared risk” paradigm based on the comparative biology of environment–host interactions in different species.  相似文献   

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The anion–π interactions between Br, Cl, F and H anions and hexafluorobenzene (HFB), 1,2,4,5-tetracyanobenzene (TCB) and tetracyanopyrazine (TCP) have been studied by standard and counterpoise (CP) corrected methods at HF, B3LYP and MP2/6-31+ + G (d,p) levels of theory. The complexation energies were corrected for basis set superposition error (ΔE BSSE) and zero point energy (ΔE BSSE + ZPE). Also, the B3LYP results were corrected by single-point calculation at B3LYP/aug-cc-PVTZ level of theory. Although the CP-corrected method results in higher distances between anions and rings, the standard method gives lower complexation energies. TCP…X series gives higher complexation energies in both CP-corrected and standard methods. Topological analysis of the charge density ρ(r) has been performed by the means of atoms in molecules method on the wave functions obtained at MP2/6-31+ + G (d,p) level of theory. The number and the nature of critical points depend on aromatic ring and anion. Natural bond orbital analysis indicates that nX → π*CC and nX → π*CN interactions are the most important interactions for TCB (and HFB)…X and TCP…X complexes, respectively.  相似文献   

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Govindjee  Šesták  Z.  Peters  W.R. 《Photosynthetica》2002,40(1):1-11
The history of the journals Photosynthetica and Photosynthesis Research is traced from its beginning. Their development is related to the history of several publishers (Dr W. Junk Publishers, Martinus Nijhoff, Kluwer Academic Publishers). This account is based on recollections and records of the authors, Ad C. Plaizier, and René Marcelle (the first Editor-in-Chief of Photosynthesis Research).  相似文献   

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莫怀东 《生物学通报》1994,29(12):16-16
化石、“活化石”与孑遗生物莫怀东(四川省仪陇县教师进修学校637600)化石、“活化石”、孑遗生物,是生物教学中提到的3个名词术语,由于三者既有相似之处,又有不同所在,学生学了之后,往往含糊不清。笔者就多年来生物教学的一些体会,充实一些必要的内容。化...  相似文献   

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Information can be conceived as being composed of two complementary components: novelty and confirmation. Whenever either of the two is zero, information is zero. Genetic information too requires both novelty and confirmation. Evolution can be seen as the history of diversification. Selection alone reduces diversity. Recessivity appears to serve as a mechanism to protect diversity against selection. So does the geographical and behavioural “separation” of species. Both recessivity and separation can be seen as “error-friendly”, a broader concept that is supportive of diversity, learning and further evolution. The principle should also be obeyed in technological systems. Received: 4 October 1997 / Accepted in revised form: 26 August 1998  相似文献   

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生物是一门实验学科。生物教学中,适当适度增加一些实验,可以激发学生的学习兴趣,把外在的信息转化为内驱力,并实现理论和实践相结合,体现学中用、用中学。  相似文献   

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D. E. Tyler 《Human Evolution》2003,18(3-4):229-241
There are now eleven known mandibular remains from the Lower and Middle Pleistocene of Java, all but one being from the Sangiran site. All of these have been assigned toHomo erectus by most workers, while others have suggested as many as four different hominoid taxa. The author finds that the jaws cannot be a homogeneous sample. Morphologically, they are a mixture of undoubtedH. erectus, “H. meganthropus,” and possibly a pongid. If the jaws are allH. erectus then they have a sexual dimorphism exceeding that of modern gorillas. The case of“Pithecanthropus dubius” (Sangiran 5) is even less certain; even its hominid status is disputed. If it is indeedHomo it must be placed with the other“H. meganthropus” specimens. Its size and morphology are well beyond the known range anyH. erectus.  相似文献   

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