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全方位四足步行机器人的运动学研究 总被引:6,自引:1,他引:6
本文将全方位四足步行机器人在每一瞬时视为一个多环空间机构。利用空间多环机构的理论逐环进行位置分析,导出在两类已知条件下机体运动与四条腿运动之间的关系。在此基础上,给出它们之间的速度,加速度关系式。 相似文献
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Albert Lee Stephanie L. Rayner Serene S. L. Gwee Alana De Luca Hamideh Shahheydari Vinod Sundaramoorthy Audrey Ragagnin Marco Morsch Rowan Radford Jasmin Galper Sarah Freckleton Bingyang Shi Adam K. Walker Emily K. Don Nicholas J. Cole Shu Yang Kelly L. Williams Justin J. Yerbury Ian P. Blair Julie D. Atkin Mark P. Molloy Roger S. Chung 《Cellular and molecular life sciences : CMLS》2018,75(2):335-354
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disorders that have common molecular and pathogenic characteristics, such as aberrant accumulation and ubiquitylation of TDP-43; however, the mechanisms that drive this process remain poorly understood. We have recently identified CCNF mutations in familial and sporadic ALS and FTD patients. CCNF encodes cyclin F, a component of an E3 ubiquitin–protein ligase (SCFcyclin F) complex that is responsible for ubiquitylating proteins for degradation by the ubiquitin–proteasome system. In this study, we examined the ALS/FTD-causing p.Ser621Gly (p.S621G) mutation in cyclin F and its effect upon downstream Lys48-specific ubiquitylation in transfected Neuro-2A and SH-SY5Y cells. Expression of mutant cyclin FS621G caused increased Lys48-specific ubiquitylation of proteins in neuronal cells compared to cyclin FWT. Proteomic analysis of immunoprecipitated Lys48-ubiquitylated proteins from mutant cyclin FS621G-expressing cells identified proteins that clustered within the autophagy pathway, including sequestosome-1 (p62/SQSTM1), heat shock proteins, and chaperonin complex components. Examination of autophagy markers p62, LC3, and lysosome-associated membrane protein 2 (Lamp2) in cells expressing mutant cyclin FS621G revealed defects in the autophagy pathway specifically resulting in impairment in autophagosomal–lysosome fusion. This finding highlights a potential mechanism by which cyclin F interacts with p62, the receptor responsible for transporting ubiquitylated substrates for autophagic degradation. These findings demonstrate that ALS/FTD-causing mutant cyclin FS621G disrupts Lys48-specific ubiquitylation, leading to accumulation of substrates and defects in the autophagic machinery. This study also demonstrates that a single missense mutation in cyclin F causes hyper-ubiquitylation of proteins that can indirectly impair the autophagy degradation pathway, which is implicated in ALS pathogenesis. 相似文献
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Mailman MD Feolo M Jin Y Kimura M Tryka K Bagoutdinov R Hao L Kiang A Paschall J Phan L Popova N Pretel S Ziyabari L Lee M Shao Y Wang ZY Sirotkin K Ward M Kholodov M Zbicz K Beck J Kimelman M Shevelev S Preuss D Yaschenko E Graeff A Ostell J Sherry ST 《Nature genetics》2007,39(10):1181-1186
The National Center for Biotechnology Information has created the dbGaP public repository for individual-level phenotype, exposure, genotype and sequence data and the associations between them. dbGaP assigns stable, unique identifiers to studies and subsets of information from those studies, including documents, individual phenotypic variables, tables of trait data, sets of genotype data, computed phenotype-genotype associations, and groups of study subjects who have given similar consents for use of their data. 相似文献
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扩频通信最初是作为保密通信的方法用在军事通信中,现在,扩频通信已经成为商业移动通信的核心技术。本书是一本介绍扩频通信的专著,提供了扩频系统的基础理论公式的推导,虽然侧重扩频理论,但在具体实例上,作者还是根据问题的重要性及对研究人员的兴趣加以选择讲解的。每章的最后配有练习题,可以帮助读者更好地理解问题;书后还有四章附录,介绍了阅读本书时所要掌握的数学原理。 相似文献
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Don Ihde 《Foundations of Science》2012,17(4):369-372
Postphenomenology, in a complementary role with other science studies disciplines, remains within the trajectory of those theories which reject early modern epistemology and metaphysics, including rejection of ‘subject’–‘object’ distinctions, and holds, instead, to an inter-relational, co-constitutive ontology. Here the critiques which sometimes echo vestiges of such early modern epistemology are counter-challenged. 相似文献
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Don C. Erman 《西北部美国博物学家》2011,36(1)
Peat cores along transects of seven minerotrophic peatlands (fens) in the Sagehen Creek basin were made in 1972. The areas were all shallow, sloping peatlands from 67 to 206 cm in maximum depth. Cores from one fen contained layers of charcoal and clay that suggested fire followed by fen regeneration. Profiles from Mason Fen suggested that the peat mass was moving downslope, creating splits and ridges with surface pools at right angles to the slope. Comparison of a profile made in 1958 with 1972 showed further evidence of downslope mass movement and expansion of the surface area. 相似文献
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Madhusudhan N Harrington J Stevenson KB Nymeyer S Campo CJ Wheatley PJ Deming D Blecic J Hardy RA Lust NB Anderson DR Collier-Cameron A Britt CB Bowman WC Hebb L Hellier C Maxted PF Pollacco D West RG 《Nature》2011,469(7328):64-67
The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior, as opposed to the silicate-dominated composition found on Earth; the atmosphere can also differ from those in the Solar System. The solar C/O is 0.54 (ref. 3). Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b (ref. 6) that reveals C/O?≥?1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapour and enhanced in methane, each by more than two orders of magnitude compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T?>?2,500?K) of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day-night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres. 相似文献
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