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排序方式: 共有237条查询结果,搜索用时 15 毫秒
231.
232.
Locomotor primitives in newborn babies and their development 总被引:1,自引:0,他引:1
Dominici N Ivanenko YP Cappellini G d'Avella A Mondì V Cicchese M Fabiano A Silei T Di Paolo A Giannini C Poppele RE Lacquaniti F 《Science (New York, N.Y.)》2011,334(6058):997-999
How rudimentary movements evolve into sophisticated ones during development remains unclear. It is often assumed that the primitive patterns of neural control are suppressed during development, replaced by entirely new patterns. Here we identified the basic patterns of lumbosacral motoneuron activity from multimuscle recordings in stepping neonates, toddlers, preschoolers, and adults. Surprisingly, we found that the two basic patterns of stepping neonates are retained through development, augmented by two new patterns first revealed in toddlers. Markedly similar patterns were observed also in the rat, cat, macaque, and guineafowl, consistent with the hypothesis that, despite substantial phylogenetic distances and morphological differences, locomotion in several animal species is built starting from common primitives, perhaps related to a common ancestral neural network. 相似文献
233.
Purification of a Low Molecular Weight Fucoidan for SPECT Molecular Imaging of Myocardial Infarction
Pierre Saboural Frédéric Chaubet Francois Rouzet Faisal Al-Shoukr Rana Ben Azzouna Nadia Bouchemal Luc Picton Liliane Louedec Murielle Maire Lydia Rolland Guy Potier Dominique Le Guludec Didier Letourneur Cédric Chauvierre 《Marine drugs》2014,12(9):4851-4867
Fucoidans constitute a large family of sulfated polysaccharides with several biochemical properties. A commercial fucoidan from brown algae, containing low molecular weight polysaccharidic species constituted of l-fucose, uronic acids and sulfate groups, was simply treated here with calcium acetate solution. This treatment led to a purified fraction with a yield of 45%. The physicochemical characterizations of the purified fucoidan using colorimetric assay, MALLS, dRI, FT-IR, NMR, exhibited molecular weight distributions and chemical profiles similar for both fucoidans whereas the sulfate and l-fucose contents increased by 16% and 71%, respectively. The biodistribution study in rat of both compounds labeled with 99mTc evidenced a predominant renal elimination of the purified fucoidan, but the crude fucoidan was mainly retained in liver and spleen. In rat myocardial ischemia-reperfusion, we then demonstrated the better efficiency of the purified fucoidan. This purified sulfated polysaccharide appears promising for the development of molecular imaging in acute coronary syndrome. 相似文献
234.
Currently, increasing pollutants in the environment lead to an increase in the use of plant oil based biolubricants. These products could lead to a significant reduction in environmental pollution and thus contribute to the discovery of a replacement for petroleum-based lubricants. Plant oils are advantageous because they are rapidly biodegradable, renewable, excellent lubricants and inexpensive to produce. However, these oils show poor stability to oxidation and unfavorable properties at low temperatures. Thus, this work outlines modifications in the epoxidation, oxirane ring opening, esterification and acylation reactions used to produce oleic acid based triester derivatives. These products have improved physicochemical and tribological properties that make them good biolubricant base stock candidates. Octyl 9-(lauroyloxy)-10-(behenoxy)octadecanoate 22 has the lowest pour point (−45 °C) while octyl 9-(lauroyloxy)-10-(octyloxy)octadecanoate 16 has the highest onset temperature. Based on the results, an increase in mid chain substituent length improves the pour point and anti-wear properties but conversely lowers the onset temperature. 相似文献
235.
Silveira Diógenes Cecchin Basso Simone Meredith Scheffer Ebone Luciano Antônio Caverzan Andréia Machado Juliana Medianeira Schaeffer Afonso Henrique Folchini Jessica Aneris Lângaro Nadia Canali 《Journal of Crop Science and Biotechnology》2022,25(1):39-50
Journal of Crop Science and Biotechnology - The runout of newly cultivated areas in the world without recurring to the deforestation, demand a necessity to improve yield to sustain a growth... 相似文献
236.
The genus Aegilops L. is a very important genetic resource for the breeding of bread wheat Triticum aestivum. Therefore, an accurate and easy identification of Aegilops species is required. Traditionally, identification of Aegilops species has relied heavily on morphological characters. These characters, however, are either not variable enough among Aegilops species or too plastic to be used for identification at the species level. Molecular markers that are more stable within
species, therefore, could be the alternative strategy towards an accurate identification. Since the chloroplast DNA has a
lower level of evolution compared to the nuclear genome, an attempt was made in this study to investigate polymorphism in
the chloroplast DNA among 21 Aegilops species (including Ae. mutica that is now known as Amblyopyrum muticum) and between the latter and T. aestivum to generate markers for the diagnosis of all targeted species. Cleaved amplified polymorphic sequence (CAPS) applied on 22
coding and non-coding chloroplast regions using 80 endonucleases and sequencing of two of those regions revealed little polymorphism
between T. aestivum and the various Aegilops species examined and to a less extent was the variation among Aegilops species. Polymorphism observed among species analysed allowed the discrimination of T. aestivum and 12 Aegilops species. 相似文献
237.
Rioja Rose Angeli Palomar-Abesamis Nadia Juinio-Meñez Marie Antonette 《Aquaculture International》2022,30(2):1087-1088
Aquaculture International - 相似文献